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Horizontes LatinoAmericanos
Number of Followers: 0  Open Access journalISSN (Print) 2318-8626 Published by Fundação Joaquim Nabuco  [3 journals]
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- A Density Functional Theory Study of Adsorption Ethionamide on the Surface
of the Pristine, Si and Ga and Al-Doped Graphene
Abstract: In this research, the adsorption behavior of pristine, Si- and Ga- and Al-doped graphene is investigated toward ethionamide (EA) using Density Functional Theory (DFT) calculations. Total energies and geometry optimizations were obtained and Density of State (DOS) analysis was performed at B3lyp level of theory with the 6-31G* basis set. The adsorption energy (Ead) between EA and the pristine, Si-, Ga- and Al-doped graphene is changed in the following order: Ga-Complex-N(ring) > Al- Complex-N(ring) > Si-Complex-N(ring) > Complex-S. The Ead of the Graphene-EA complex is -2.552 kcal/mol, which is low and shows that the adsorption is physical. The % ΔEg= -59.61% for Si-doped graphene EA shows the high sensitivity of the Si-doped graphene to the adsorption of EA. The Eg for Ga-doped graphene-EA decreases significantly from 2.35 to 1.11 eV and the rate of change is %ΔEg = -52.75%, showing the high sensitivity of Ga-doped graphene to the adsorption of EA. However, the high Ead of -36.66 kcal/mol shows that the Ga-doped graphene can be used as a suitable sensing device only at higher temperatures. The % ΔEg= -58.98 % for Al-doped graphene-EA indicates the high sensitivity of the Al-doped graphene to the adsorption of EA. The Ead of -34.53 kcal/mol can be used as a suitable sensing device only at higher temperatures.
- Impact of Chitosan-Capric Acid Nanogels Incorporating Thyme Essential Oil
on Stability of Pomegranate Seed Oil-in-Water Pickering Emulsion
Abstract: The aim of this study was to obtain a stable Pomegranate Seed Oil (PSO)-in-water Pickering emulsion stabilized by chitosan (CS)-capric acid (CA) nanogels incorporating Thyme Essential Oil (TEO). Firstly, CS-CA nanogels were synthesized at different ratios of CA to CS (0.25:1, 0.5:1, and 0.75:1). Scanning electron microscopy images showed that by increasing the CA to CS ratio, the uniformity of particles was increased. In the following, CS-CA nanogels were used to stabilize PSO-in-water emulsions. The findings revealed that the most stable emulsion was obtained at pH 8, CA-to-CS ratio of 0.5:1, and an oil-to-nanogel ratio of 10:1. In addition, the interfacial structure of emulsion droplets indicated that the CS-CA nanogels contributed to the stability of emulsion through both the formation of an interface layer and a network on the surface of dispersed droplets. Finally, the oxidative stability and microstructure of the emulsions stabilized by CS-CA nanogels incorporating TEO (0.1%) were evaluated. The results showed that TEO increased the oxidative stability of the emulsion and reduced the emulsion droplet size.
- Three-Layer Magnetic Nanocomposite Containing Semiconductor Nanoparticles
as Catalyst for Dye Removal from Water Solutions under Visible Light
Abstract: In the present work, a three-layer magnetic nanocomposite containing ceria nanoparticles was synthesized as Fe3O4@SiO2@CeO2 by precipitation method and after characterization was used as a photocatalyst for the degradation of malachite green dye from industrial wastewater under visible light. The influence parameters such as pH, initial dye concentration, photocatalyst amount, and process time on the malachite green dye removal were investigated and optimized. Under optimum conditions (pH = 9, the photocatalyst amounts of 0.05 g, the reaction time of 40 min, and the initial solution concentration of 10 ppm), the results indicated that the synthesized nanostructure has a desirable performance for dye. The removal percentage remained higher than 90% after 5 times use and the photocatalyst could be quickly separated from the aqueous solution with the assistance of the external magnetic field. According to the calculation, the second pseudo-model was selected as the kinetic model of photocatalytic degradation.
- New Catalyst for Biodiesel Formation: Synthesis, Structural Elucidation
and Quantum Chemical Calculations of New Ni(II) Complexes
Abstract: New Ni(II) complexes were synthesized from the coordination of the ligands derived from benzo[1,2-c]isoxazoles with Ni(II) cation.. The structure of the new complexes was characterized by elemental analyses, mass, and IR spectra. To gain a deeper insight into the geometry of Ni(II) complexes, a quantum chemical investigation was performed. The obtained results from experimental and theoretical arguments confirmed a square-planar geometry for Ni(II) complexes. These complexes were examined as homogeneous catalysts for the transesterification of corn oil with methanol. The structure of the obtained product was confirmed by 1H NMR analysis. The catalytic results showed that the new Ni(II) complexes can be considered potential candidates for the development of a new catalytic system for biodiesel production.
- Characterization of Fresh and Regenerated Industrial Hydrocracking
Catalysts; Study Causes of Deactivation
Abstract: In this investigation, fresh and regenerated Ni-W-Alumina-Zeolite industrial hydrocracking catalysts are characterized via several analyzing methods, including XRF, XRD, BET adsorption, FT-IR, FESEM-EDS, and TGA-DTA to understand the phenomena affecting trend towards their deactivation. The XRD patterns represented the presence of main phases of Al2O3/Y-zeolite as support and NiWO4/WO3 as active compounds. For the catalysts subjected to a three-year reactor operation/regeneration cycle, the XRF analysis revealed elemental enhancement of Fe, Na, V, Pb, Sb, and S, mostly from an outsourced environment. The BET and BJH analyses represented cylindrical shape mesoporosity for the samples, while the total pore-specific surface area and volume were reduced from 287.73 m2/g and 0.46 cm3/g to 160.84 m2/g and 0.40 cm3/g for fresh and regenerated samples, respectively. The latter results indicated possibly filling the pores with impurities and/or sintering of pores. By considering FESEM images, the smooth surface of the fresh sample and indented/corroded characteristics of the regenerated one were seen. The variety of analyses portrayed the increasing trend of the poisoning factors and the structural malfunction of the catalysts towards irreversible deactivation.
- Preparation, Characterization, and Kinetics Model of MoCo/γ-Al2O3
Catalysts for Oxidative Desulfurization of Light Naphtha
Abstract: The subject of this work is to study the effect of pH, molybdenum content and some of the transition metals (such as Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel) on the catalyst properties and performance of oxidative desulfurization (ODS). To achieve this aim, the mesoporous 5%Co10%Mo/γ-Al2O3 catalyst was prepared by incipient wetness impregnation method. Then, the as-synthesized catalysts were characterized by X-Ray Diffraction (XRD), N2-adsorption/desorption, and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), Scanning Electron Microscopy (SEM) and NH3-Temperature Programmed Desorption (NH3-TPD). The catalytic activity was measured with catalytic ODS setup. The catalyst with 10wt%Mo (as an active metal) and 5wt%Co content (as a promoter) at pH=4 represented the optimum performance for oxidative desulfurization. The 5%Co10%Mo/γ-Al2O3 has the Surface Area =170.61 m2/g, Pore Volume =0.64 cm3/g, Average Pore Diameter = 15.18nm when these parameters were increased, it led to the best operation condition of sulfur removal. The SEM images showed that the application of Co and Mo metals reaches more homogenous impregnation. The NH3-TPD result introduced the strong acidic sites of 5%Co10%Mo/γ-Al2O3. The obtained results proved that the total sulfur (all kind of sulfur in the feed) of light naphtha decreased from 160ppm to 20ppm during ODS process with the optimized catalyst. In that case, the kinetics of oxidative desulfurization of the optimized catalyst (5%Co10%Mo/γ-Al2O3) was studied. Moreover, a kinetic affinity model was utilized to determine the kinetic parameters of this reaction and the modeling results showed good agreement with experimental data.
- Synthesis, Molecular Docking and Anticancer Activity of Novel
(E)-5-((1-phenyl-1H-1,2,3-triazol-4-YL)Methylene)-2-thioxothiazolidin-4-one
Analogues
Abstract: A novel series of (E)-5-((1-Phenyl-1H-1,2,3-triazol-4-yl)methylene)-2-thioxothiazolidin-4-one analogues were designed for anticancer activity and synthesized by the reaction of 1-Aryl-1H-1,2,3-triazole-4-carbaldehydes with 2-thioxothiazolidin-4-one. The synthesized compounds were analyzed by IR, 1HNMR, 13CNMR, and mass spectrometry. The compounds were screened for in vitro anticancer activity using four cancer cell lines viz. Lung (A549), Colon (HT-29), Breast (MCF-7), and Melanoma (A375), resulted from most of the compounds showed moderate to better activity against all cell lines, among them the compounds 6g and 6j were the most potent in all investigated cancer cell lines (lung, colon, breast, and melanoma. The compounds were studied in molecular docking studies, which resulted in a significant dock score shown with all the compounds. The compounds 6i and 6b have shown the highest dock scores.
- Modeling and Simulation of Partial Oxidation of Methanol to Formaldehyde
on FeO/MoO3 Catalyst in a Catalytic Fixed Bed Reactor
Abstract: A two-dimensional mathematical model was developed for a porous heterogeneous catalytic fixed bed reactor. The model took into account the effect of heat generated by adsorption of reactants on the catalyst surface and heat transfer from the fluid phase to the surroundings which have a significant effect on reactor performance, especially at reactor hotspot. The developed model predicted the partial oxidation of methanol to formaldehyde on FeO/MoO3 catalyst, a complex reaction system. Excellent agreement was achieved when the resultant simulated results were compared with experimental data in the literature. The proposed model predicted the location of the hotspot at a dimensionless distance of 0.4413 (= 0.0309 m) the same as the experiment value but with a temperature of 619 K compared with an experimental value of 622 K. The conventional heterogeneous and pseudo-homogeneous models predicted the hotspot temperature to be about 8 K and 34 K lower than the experimental value respectively.
- Optimal Synthesis of Aromatic Carbonyl Compounds by Electrooxidation of
Soda Lignins on Stainless steel and TiMMO Anodes
Abstract: Electrooxidation (EO) studies were conducted on Wheat Straw Soda Lignin (WSSL), and bagasse soda lignin (BSL) for the synthesis of aromatic carbonyl compounds (COarom). Stainless Steel (SS), and titanium mixed metal oxide (TiMMO) anodes were used for the purpose. Experiments were designed according to Box Behnken Design (BBD), and Central Composite Design (CCD). The process parameters, namely EO current density, and EO time, were optimized using Response Surface Methodology (RSM) to obtain the maximum yields of different COarom, individually as well as collectively. A maximum of 30% cumulative yield of COarom, based on the total amount of lignin, could be obtained from BSL under optimized conditions of 2.24 mA/cm2 EO current density, and 18 h EO time using SS anode. Among individual compounds, vanillin was produced with the highest yield of 20% of starting BSL with EO current density, and EO time optimized to 5.87 mA/cm2, and 18 h, respectively. In all cases, SS anode fares better than TiMMO anode.
- Synthesis of Hexafunctional Epoxide Resin and Application on Jute and
Glass Reinforced Composites
Abstract: Bisphenol-A, formaldehyde, and epichlorohydrin form hexafunctional epoxy resin. The curing behavior of resin has been evaluated by using five different hardeners viz. diethyl triamine, triethyl tetraamine, phenalkamine, polyamido amines, and polyamides. The resin was further characterized by epoxy equivalent weight, hydrolyzable chlorine content, volatile content, viscosity and rise in viscosity, weight average molecular weight, and Fourier Transform InfraRed (FT-IR). spectroscopy The hexafunctional epoxy resin was used for the preparation of jute and glass-reinforced composites. All composites were characterized by their mechanical properties, thermal properties, and chemical resistance.
- Microwave Induced Sustainable Isolation of Laccaic Acid from Lac Insect
for Nylon Dyeing
Abstract: Green technologies in isolation and extraction of natural products have always been welcomed due to awareness about environmental standards for global health. The current research was performed to use microwave energy to extract natural dyes from lac insects and their application onto nylon fabric. For isolation of natural dye from lac insect in acidic and acidified methanolic media Mw irradiation for 3, 5, and 7 min. has been given and used to dye nylon fabric. Bio-mordants from herbal-based sources such as Acacia and Turmeric were also employed to develop new shades and to improve fastness properties in comparison with metallic salts of Al (Alum) and Fe (ferrous sulfate). The evidence from this study suggests an increase in color yield (K/S) with the use of 5 min. of microwave energy when acid solubilized extract of lac insect was used to dye onto nylon fabric. It has been demonstrated also that in the case of the pre-mordanting method, 5% of Acacia and 1% of Turmeric give the best fastness properties and the highest color yields. It is concluded that Microwave energy has an excellent efficacy to isolate the colorant, whereas the addition of bio-mordants has made the process more sustainable and greener.
- The Efficiency of Physical Equilibrium and Non-Equilibrium Models for
Simulating Contaminant Transport in Laboratory-Scale
Abstract: In order to better management of contaminants in porous media, it is essential to recognize their transport behavior using appropriate models. In this research, Convection-Dispersion Equation (CDE) and Mobile-ImMobile (MIM), as physical equilibrium and non-equilibrium models, respectively, were used to simulate the bromide transport (as a conservative contaminant) through undisturbed and saturated clay loam and sandy loam soil columns (diameter of 10 and height of 40 cm). To simulate the transport, CXTFIT2.1 software, in which the CDE and the MIM models are included, was used. The values of mass transfer coefficient (ω<100) and mobile water fraction (β<1) as an indicator for determining the equilibrium and non-equilibrium indicated that bromide transport behavior within these columns was anomalous or non-Fickian transport. Hence, non-equilibrium and the MIM model are suitable and more efficient than the Fickian-based CDE. The fitted breakthrough curves (BTCs) and the larger determination coefficient (R2) and the smaller Root Mean Square Error (RMSE) values of the MIM model compared to those of the CDE confirmed the effectiveness of the MIM model in simulating bromide transport in the clay loam and sandy loam soil columns.
- Neural Network, Isotherm, and Kinetic Study for Wastewater Treatment Using
Populus alba’s Pruned Material
Abstract: Dyes are utilized in several plants and factories. Contaminated wastewaters containing dyes cause many illnesses and have many adverse effects on humans, animals, and plants. This research aims to the usage of Populus alba tree’s sawdust as a costless pruned agricultural waste material for the removal of crystal violet from simulated wastewater in batch adsorption experiments. The dye removal process by the adsorbent was performed by varying various parameters such as the weight of the adsorbent, pH of the solution, adsorption time, and the initial dye concentration. Generally, increasing the weight of the adsorbent and decreasing the initial dye concentration led to increasing removal efficiency. The optimum solution pH was found to be 6.5. Also, the optimum weight of the adsorbent and the optimum initial dye concentration were found to be 0.15 g and 10 mg/L, respectively. Moreover, the adequate adsorption time for the accomplishment of the treatment procedure was 10 min. Adsorption data were fitted well by the Langmuir adsorption isotherm model and the maximum amount of the adsorbate on the adsorbent (qmax) was calculated to be 12.25 mg/g. The kinetic study data illustrated the adaption of the adsorption rate with the pseudo-second-order kinetic model. The results of the ANN model proved the fitness of theoretical and experimental data according to the obtained correlation coefficient values. Eventually, the dye removal efficiency reached 97% in the optimum conditions of the experiments. So the sawdust of Populus alba tree’s pruned hardwood is introduced as a costless and highly capable adsorbent for the adsorption of crystal violet from contaminated wastewaters in order to perform a successful wastewater treatment beside the accomplishment of a waste management procedure.
- Modeling and Economic Analysis of MED-TVC Desalination with Allam Power
Plant Cycle in Kish Island
Abstract: In this paper, a system consisting of the Allam cycle and Multi-Effect Distillation- Thermal Vapor Compression) MED-TVC( desalination was proposed to reduce the amount of carbon dioxide in the atmosphere. It uses wasted energy for the simultaneous production of freshwater and power. Firstly, analysis of the Allam cycle delineated that the heat capacity suitable for the desalination cycle is estimated to be 100 MW, the amount of heat from the outlet of the compressor. The MED-TVC desalination system, one of the most suitable and the most economical desalination systems, is used to combine the Allam cycle and desalination in Kish Island, located in the south of Iran. The results of this research indicate that the proposed cycle has a desirable economic performance, and the results of economic analysis using the Net Present Value (NPV) method and Internal Rate of Return (IROR) show the Payback period in this plan is 4.8 years.
- Theoretical Investigation of Entropy Generation in Axisymmetric Stagnation
Point Flow of Nanofluid Impinging on the Cylinder Axes with Constant Wall
Heat Flux and Uniform Transpiration
Abstract: Dimensionless temperature, Nusselt number, and entropy generation in stagnation flow of incompressible nanofluid impinging on the infinite cylinder with uniform suction and blowing have been presented in this study. The initial stream rate of the steady free stream is k. A similar solution of Navier-Stokes and energy equations has been presented. These equations are simplified by implementing appropriate transformations introduced in this research. The governing equations are solved where the heat flux at the cylinder’s wall is constant. All these solutions are acceptable for Reynolds numbers of 0.1-1000, various dimensionless surface diffusion, and specific volume fractions of nanoparticles where a is the cylinder radius and is the kinematic viscosity of the base fluid. The results show that for all Reynolds numbers, diffusion depth of radial and axial components of velocity field and wall shear stress increases as a result of the decline in nanoparticles volume fraction and growth in surface diffusion. Moreover, an increase in nanoparticle volume fraction and surface suction raises the heat transfer coefficient and Nusselt number. Also, the greatest amount of entropy generation is calculated.
- Energy and Exergy Analysis of Internal Combustion Engine Performance of
Spark Ignition for Gasoline, Methane, and Hydrogen Fuels
Abstract: Exergy analysis is a tool to determine the share of processes involved in transferring input functionality to the system and where the useful energy loss occurs in a system or process. In this study, an exergy comparison of the performance of an internal combustion engine with spark-ignition for gasoline, hydrogen, and methane fuels is considered. For this purpose, first, multi-zone modeling of the engine based on flame advancement has been introduced. Then, the necessary conceptual bases for performing exergy analysis of the system have been established by defining the term exergy and creating the corresponding exergy balance equations and applying them to closed systems and control volumes. This study shows that the largest share of irreversibility in the engine is related to the combustion process. Also, for stoichiometric conditions, we can mention the percentage of exergy transferred by working approximately equal for all three fuels, the highest percentage of irreversibility for gasoline, and the lowest percentage of irreversibility for hydrogen. Examining the exergy analysis results in the assumed operating conditions mentioned in the paper shows that increasing engine speed increases exergy transfer with work and decreases exergy transfer with heat. Also, increasing the equivalence ratio increases the share of exergy of the mixture inside the cylinder and decreases the irreversible share of inlet exergy.
- Numerical Investigation of Mixed Convection Flow of Viscoelastic Nanofluid
with Convective Conditions over an Exponentially Stretching Surface
Abstract: Numerical analysis is performed for a 3D incompressible viscoelastic nanofluid mixed convection flow model under the implications of convective boundary conditions towards an exponentially stretching sheet. The system that comprises differential equations of partial derivatives is remodeled into the system of differential equations via similarity transformations and then solved numerically through the Runge-Kutta-Fehlberg with shooting technique. The physical parameters, which emerge from the derived system are discussed in graphical formats. The significant outcomes of the current investigation are that the velocity field grows for a higher viscoelastic parameter while it reduces the fluid temperature. An increase in the mixed convection parameter diminishes the temperature and concentration. Further, the heat transfer rate is crumbled with the incremental values of the viscoelastic parameter. The obtained results show a better agreement with those available in the literature for limiting scenarios.
- Joint Estimation for Battery Capacity and the State of Charge Based on
Variable Time Scale
Abstract: As the core energy source of electric vehicles, power batteries directly restrict the development of electric vehicles. Accurate estimation of SOC is not only the fundamental function of the electric vehicle battery management system but also helps to improve energy utilization of batteries, safeguard the application of batteries in EVs, and extend the cycling life. However, the time-varying nonlinearity, environmental sensitivity, and irreversible decay during the use of the battery make the estimation of hidden states such as SOC a challenge to the industry. This study conducted the following research on the SOC and capacity estimation of lithium-ion batteries: (1)To achieve the co-estimation of the battery’s state and parameters, an adaptive cubature Kalman filter SOC estimation method based on random weighting (ARWCKF) is proposed, at the same time, Extended Kalman Filter (EKF) is used to identify the parameter on-line. The results verify that this approach has a better performance with the error of SOC being under 3%. (2) Aiming at the limitations of the single-time-scale joint estimation algorithm, taking accumulated discharge as the conversion standard between micro and macro time scales. The filtering performance of the algorithm is effectively evaluated based on the prediction accuracy of the terminal voltage, SOC, capacity, and the convergence rate of SOC and capacity, verifying that compared to the single-time-scale approach, this approach has better robustness and accuracy.
- Improving a Process Design for the Condensate Stabilization Unit
Abstract: The condensate stabilization process is known as a common operation in gas fields with the aim of diminishing the condensate Reid Vapor Pressure (RVP). Based on feed characteristics and specified products, condensate stabilization units can be optimized by examining different process configurations. In each configuration, there exist some criteria in terms of product quality, energy-saving, and economic recovery, which shall be investigated so that the configuration’s performance is evaluated and selected. The aim of this study is to illustrate four condensate stabilization configurations and then to determine the proper column temperature and pressure, feed split ratio, and feed tray location by means of Aspen Hysys in the configurations. In the end, it is shown that the configuration with the lowest operating pressure not only had the lowest fixed capital cost but also consumed the lowest energy due to its high separation efficiency and low energy requirement.
- Chemical Modification of Proton Exchanger Sulfonated Polystyrene with
Sulfonated Graphene Oxide for Application as a New Polymer Electrolyte
Membrane in Direct Methanol Fuel Cell
Abstract: A novel composite membrane is prepared by the dispersion of Sulfonated Graphene Oxide (SGO) in sulfonated polystyrene–polyethylene (SPS-PE) for electrolyte in the direct methanol fuel cell. For sulfonated polystyrene used the method that was patented by Makowski et al. Graphene Oxide (GO) is prepared by modified Hummer's method and is further functionalized with SO3-H. SGO is then incorporated into SPS-PE matrix using the solvent cast method to form the composite membrane. The composite membranes are characterized by FT-IR, TGA, and SEM. Oxidative resistance, water uptake, ionic conductivity, and methanol permeability are measured to evaluate its performance in a direct methanol fuel cell with a cation exchanger membrane. The membranes were confirmed to retain 1–5% water vapor at 80–140 °C in the air due to the hydrophilic of highly SPS and SGO. The ionic conductivity and permeability of the membrane to methanol were found to increase with temperature increasing. The membrane SGO-SPS–PE shows the proton conductivity of 2.74 × 10-2 S/cm at 100 °C without extra humidity supply and is very promising for high temperatures with low humidity. The high proton conductivity is ascribed to the unique composition in which the heterocyclic polymer provides the proton motion by construction diffusion and the highly SGO-SPS copolymer retains water vapor to lower the activation energy for proton conduction.
- Comparative Study and Multi-Objective Optimization of Various
Configurations in Natural Gas Liquefaction Process
Abstract: PRICO process is a promising method for liquefaction of the natural gas which is sometimes used with some optional equipment. Although the PRICO process is widely used in natural gas liquefaction, the configuration leading to the most desirable performance has not been determined. The liquefaction rate and the energy consumption are two important factors to evaluate the performance of the PRICO process. In this study, the PRICO process with five different configurations was simulated and compared. By the means of the multi-objective optimization method, the liquefaction rate and the energy consumption were optimized, simultaneously, for each of the procedures. The five different simulated configurations are simple PRICO process, simple process with the third compressor, simple process with second heat exchanger, simple process with pre-cooling heat exchanger, and full-set process. The optimization results demonstrated that the three-compressor and the full-set processes achieved the maximum liquefaction rate (96.51) and the minimum energy consumption (1219.53 kW), respectively. The economic analysis has also presented and revealed that the three-compressor process had the highest net profit (730.9288 M$/25 years) among the configurations. In other words, the three-compressor process outperformed other configurations with respect to the operation and economics (maximum liquefaction rate of 96.51 and net profit of 730.9288 M$/25 years).
- Extraction of Si from Alkaline-Roasted Boron Ore Concentrate
Abstract: The process of alkali roasting boron ore concentrate was proposed for the problems existing in the process of boron ore concentrate smelting. In this research, the influencing factors included the molar ratio of alkali to boron ore concentrate, roasting temperature, and roasting time were investigated. The single experiment and orthogonal experiments show the optimal conditions for roasting under the conditions evaluated including a temperature of 550oC, roasting time of 60 min, and a molar ratio of alkali to ore of 3:1. In the roasting process, the Si extraction correlated with the shrinking core model assuming a solid product layer according to XRD and SEM. Thus, the kinetics is controlled by diffusion through the product layer. The apparent activation energy for Si extraction was 13.47kJ/mol, and the roasting rate can be expressed as:1-(2/3α)-(1-α)2/3=1.428×10-2exp(-13470/RT)t.
- Selective Emulsion Liquid Membrane Extraction of Cu(II) Mediated by a
Schiff Base Ligand
Abstract: This study concerns the application of a Schiff base ligand of type N3O2 as a carrier in a water-in-oil emulsion liquid membrane for the selective transport of copper ions. A hydrochloric acid solution formed the internal aqueous phase (receiving phase), and the membrane was composed of a Schiff base ligand called bis(1'-hydroxy-2'-acetonaphthone)-2,2'-diiminodiethylamine (L) in dichloromethane and the non-ionic surfactant Span® 80 in paraffin. By applying the optimum conditions, a quantitative uptake of copper ions (initial concentration 5 mg/L) from the aqueous feed phase (pH 5) into the receiving phase (hydrochloric acid 0.7 mol/L), after 10 min was attained. The optimal value determined for the treat ratio allows achieving a concentration factor of >6 for the copper ions in the receiving phase. The proposed emulsion liquid membrane provided an excellent selectivity towards copper ions with respect to some associated metal ions including Cd(II), Ni(II), Zn(II), Co(II), Fe(II), and Cr(III). However, such selectivity was not observed in the competition of Cd(II) and Pb(II) ions. The breakage of emulsions and recovery of the internal phase from the membrane was performed by freezing the internal solution. The expansion of the frozen internal phase volume results in the breakage of the emulsions. The applicability of the proposed procedure was appraised by employing the method for the recovery of copper from the leached solutions of the cobalt and nickel-cadmium filter cakes of a zinc production plant.
- Molecular Docking and Computational Exploration of Isolated Drugs from
Daphne Species Against COVID-19
Abstract: The SARS-CoV-2 has initiated in Wuhan city of China and then extend all around the world as a health emergency. It begins a new research area to produce potential drugs using data-driven approaches to identify potential therapies for the treatment of the virus. This is the time to develop specific antiviral drugs using molecular docking, quantum chemical approaches, and natural products. The protease inhibitors that constitute plant derivatives may become highly efficient to cure virus-prompted illnesses. A systematic study of isolated phytochemicals was executed then frontier molecular orbitals, docking score, molecular descriptors, and active sites were compared with favipiravir, dexamethasone, redeliver, and hydroxychloroquine which are being used against COVID19 nowadays. This is the first study on the phytochemicals of Daphne species to explore their anti-SARS-CoV-2 behavior by molecular docking and quantum chemical methods.
- Production and Characterization of Flavored Dairy Dessert Containing Grape
Juice Concentrate
Abstract: Grape Juice Concentrate (GJC) contains high amounts of natural sugars, vitamins, and polyphenols so it can be used as a natural sweetener and functional ingredient. The novelty of the present study was to produce flavored dairy desserts, as well as to evaluate the effect of GJC, gelatin, and cream on its physicochemical, mechanical, and sensorial properties. In this study, optimization of breakfast flavored dairy dessert formulation containing GJC was done using design expert and response surface methodology. The effects of cream (75-90 %), gelatin (0 - 0.5 %), and GJC (10-25 %) on the properties of flavored dairy desserts were evaluated. The samples were subjected to fat, acidity, pH, total solids content, sugar content, hardiness, color, antioxidant activity, and sensory attributes. At first, the modeling of responses was done using data regression analysis, and then 3D charts were drawn for each response. The results showed that the samples became firmer, and darker in color as the level of GJC increased. The antioxidant activity of the desserts was increased mostly by GJC level. The maximum hardness and radical inhibitory activity of samples were 1380 g and 73.5%, respectively. The general acceptability of the desserts was affected by Antioxidant; Dairy dessert; Grape juice concentrate; Response surface methodologyby the amount of GJC. Based on the standard range of responses and the most desirability, the optimal point was obtained. At the optimal point, the amounts of cream, GJC, and gelatin were 75.05, 20.59, and 4.36% respectively. Flavored dairy desserts could be considered to be a suitable source of vitamins, soluble fiber, antioxidants, amino acids, and a good source of natural sweets.
- Determination of Bioactive Properties, Phenolic Compounds and Mineral
Contents of Boiled Fruit Juice Types
Abstract: Antioxidant activity, total phenol, total flavonoid, and anthocyanin contents, phenolic compounds, and macro-and microelement contents of concentrated fruit pulp (boiled juices) were determined. While antioxidant activities of marmalade samples varied between 99.6% (Mahaleb) and 117.2% (Cornus), total phenolics of boiled juices changed between 103.52 (Mahaleb) mg GAE/100g and 126.63 mg GAE/100g (Cornus). In addition, while gallic acid contents of marmalade (boiled juices) extracts are determined between 0.91 (Mahaleb) and 6.27 mg/100g (Cornus), (+)-Catechin contents of marmalade samples varied between 3.29 mg/100g (Mahaleb) and 9.61 mg/100g (Cornus). K and P contents of boiled juices were found between 271.37 mg/Kg(Rosa) and 8004.00 mg/kg (Mahaleb) to 55.12 (Cornus) and 415.12 (Mahaleb) mg/kg, respectively. Fe contents of boiled juices changed between 12.97 (Rosa) and 16.92 mg/kg (Cornus). Among samples, the highest Cu (1.75 mg/kg), Mn (1.08 mg/kg), and Zn (7.62 mg/kg) contents were found in mahaleb boiled juice. According to the results, boiled juice samples are rich in bioactive compounds, phenolics, and some minerals (Ca, K, Mg, Na, and P).
- Qualitative Aspects of Probiotic Flavored Soymilk-Based Yogurt
Abstract: In this study, the effects of soymilk to cow's milk ratio (0:100, 25:75, 50:50, 75:25, 100:0), kind of commercial starter culture (ABY-1 or ABY-2 containing Bifidobacterium lactis BB-12, Lactobacillus acidophilus LA-5, and yogurt bacteria, and natural fruit concentrations (kiwi, pear, strawberry or apricot) on biochemical characteristics, viability and sensory properties of probiotic flavored soy-yogurt were investigated. These properties were analyzed during and at the end of fermentation as well as during the cold storage (21 days). The highest viability of probiotics (p<0.05) was observed when ABY-1 starter culture with soymilk to cow's milk ratio of 50:50 was applied, whilst the best sensory attributes were related to the treatment with the highest cow's milk content and ABY-1 starter culture. Considering all aspects, the treatment of ABY-1/50:50 (cow's milk: soymilk) which renders the highest viability and acceptable sensory properties was selected as an optimum. Viability was over 108 cfu/mL during the storage period (5˚C. 21 days) for all treatments of ABY-1/50:50 containing fruit concentrates. Those which had apricot and strawberry flavorings showed the best sensory acceptance.
- Expression and Purification of Brucella spp. Lumazine Synthase Decameric
Carrier in Fusion to Extracellular Domain of Influenza M2E Protein
Abstract: Brucella spp. Lumazine synthase enzyme is a decameric protein carrier that displays foreign antigens effectively in a polyvalent manner. The applied strategy using this molecule results in a higher density of antigens and enhances the immunogenicity of peptide vaccines. In the current study, Brucella lumazine synthase (BLS) was applied for fusion with influenza matrix protein 2 ectodomain (M2E) as a foreign peptide. The primary studies were based on bioinformatics tools and the fusion was expressed and purified in the following levels. Forming of the decamer was confirmed by electrophoresis and western blotting techniques. Influenza matrix protein 2 was stably expressed at the 10 amino terminals of lumazine synthase. The purified fusion was injected into mice and immune responses were evaluated with the indirect enzyme-linked immunosorbent assay (ELISA) technique. According to ELISA results yield of the purification process was 41% with the ion-exchange method and the protein was as a single band in Sodium Dodecyl Sulfate PolyAcrylamide Gel Electrophoresis (SDS-PAGE). The titer of immunized mice serum with a decameric fusion of lumazine synthase and matrix protein (M2BL) was determined to be more than 1:32000 by indirect ELISA. The level of responses against matrix protein in the decameric state of M2BL, was about 20% higher than monomer M2BL. Anti M2BL was cross-reacted effectively with influenza M2E and in comparison with samples injected with adjuvant, the level of antiM2E was similar. The results in this study confirm the role of multi-copy presentation systems and the applicability of BLS as an antigen carrier and adjuvant in designing peptide vaccines.
- Aflatoxin M1 Reduction by Probiotic Strains in Iranian Feta Cheese
Abstract: Among the fermented products, cheese has a good potential to deliver probiotic microorganisms into the gastrointestinal system due to its high protein and fat contents. The contamination of milk with aflatoxin M deserves attention concerning cheese consumption due to the harmful effects on human health. The present research studied the reduction of aflatoxin M1 (AFM1) by two well-known probiotic strains in artificially aflatoxin-contaminated Feta cheese. Changes in pH, the viability of the probiotic strains, and the level of aflatoxin in the samples were analyzed during 60-day storage. The results showed that all samples containing probiotics dramatically reduced the AFM1 levels. From both the health and economic aspects, the B. bifidum species at an inoculation level of 107 CFU/mL has proven to be the best treatment, due to the lowest cost of probiotics, highest survival rate, and 30.12% reduction of AFM1.
- The Effect of Different Light Spectra on Beta-Carotene Production by
Dunaliella salina
Abstract: This study focused on the effect of different light intensities and spectra on the beta-carotene production within Dunaliella salina cells (green eukaryote microalgae) which are purified from Urmia Lake in northwest Iran. For this purpose, four LED light spectra (white light: 360–760 nm, red light: 620–645 nm, yellow light: 587–595 nm, and blue light: 460–475 nm) were used in this experimental research. The light intensity of 200 µmol/(m2 s) was considered for each LED light spectra. The highest beta-carotene content extracted under a sequential combination of colored light (white, blue, red, and yellow respectively) was 16.93 µg of beta-carotene per mg of cell dry weight and the highest accumulated beta-carotene within the cells among single-colored light was 15.16 µg /mg when the cells were cultivated under yellow light.
- Modeling of Ultrasound-Assisted Extraction, Chemical Composition,
Antioxidant Activity, Rheological Aspects, and Biological Properties of
“Barhang-e-Kabir” Mucilage
Abstract: In this study, response surface methodology (RSM) was used to investigate the influence of independent process parameters including water to seed ratio (g/g), temperature (°C), time (min), and ultrasonic intensity (%) on the extraction yield of “Barhang-e-Kabir”. Chemical composition, monosaccharide composition (using HPAEC-PAD), molecular conformation, molecular weight properties, Surface tension, ζ-potential, particle size distribution, Fourier Transform InfraRed (FT-IR) spectroscopy, color measurement, Total Phenol Content (TPC), Total Flavonoid Content (TFC), Antioxidant Activity (AA), antimicrobial and dilute-solution and steady-state behavior were evaluated. The optimum condition to obtain maximum extraction yield (13.1 %) was extraction temperature 70 ᵒC, extraction time 40 min, water to seed ratio of 1:10, and ultrasonic power of 90 %. Plantago major gum (PMG) had 89.24% carbohydrate, 4.53% ash, 4.11% moisture, and 2.12% protein. Viscometric molecular weight and average molecular weight were found to be 1.13 ×105 g/mol and 9.9 ×105 g/mol, respectively. The intrinsic viscosity of PMG was 12.56 dL/g in deionized water at 25 ºC. Steady shear measurement demonstrated that PMG is a shear-thinning fluid with high viscosity at low concentration. TPC, TFC and AA (IC50) tests of PMG showed 89.80 ± 1.23 mg GAE/g dry sample, 123.25 ± 1.32 mg g−1dry sample, and 470.45 ± 0.35 µg/mL, respectively. Prevention of linoleic acid oxidation in the system of ß-Carotene-linoleic acid was equal to 32.45 %. The results showed that Streptococcus pyogenes and Pseudomonas aeruginosa are the most sensitive and highest resistance strain to PMG, respectively.
- Green Synthesis of Copper Nanoparticles using Centaurea cyanus Plant
Extract: A Cationic Dye Adsorption Application
Abstract: In this study, copper nanoparticles (Cu-NPs) were synthesized through a green and economic technique. The Centaurea cyanus plant extract was used as an appropriate reducing and stabilizing agent in this process. The synthesized nanoparticles were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray Powder Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM) and N2 adsorption porosimetry analysis. The analysis showed that the average size of spherical nanoparticles was around 11.9 nm, with 74.2 m2/g and 0.36 cm3/g mane surface area and pore size, respectively. Then, Cu-NPs were studied as a low-cost adsorbent to remove methylene blue (MB) dye from aqueous solutions. For this purpose, Central Composite Design (CCD) under the Response Surface Methodology (RSM) was applied to design the experiments, model the data and optimize the operating conditions. The effect of various operating parameters such as pH, MB initial concentration, adsorbent amount and contact time on the MB removal was practiced. Analysis of variance (ANOVA) showed a good agreement between the experimental data and the predicted ones obtained from the quadratic model. The optimum conditions for MB removal (63.20 %) were found at pH of 6.6, MB initial concentration of 30 mg/L, adsorbent amount of 0.15 g and time of 101.5 min. The results showed that the Langmuir isotherm with maximum adoption capacity of 21.9 mg/g and pseudo-second order kinetic models with rate constant of 0.359 (g/mg) (1/min) can properly legitimize the experimental data.
- Synthesis and Characterization of a Novel Bio-Magnetically Recoverable
Palladium Nanocomposite for the Photocatalytic applications
Abstract: A novel immobilized sparteine palladium (II) complex on the bio α-Fe2O3 nanoparticles was synthesized (Pd-Sparteine- α -Fe2O3). XPS, FT-IR, and ICP were used to determine compositional information. High thermostability and magnetic properties of it were proved by TGA and VSM, respectively. The size and morphology of this heterogeneous catalyst were investigated using SEM and TEM. Photoluminescence spectrum, BET, DRS and EDAX of this novel nanocomposite were evaluated for further investigations. The synthesized magnetic nanohybrid was successfully exploited as a new recyclable heterogeneous photocatalyst in the degradation of 2,4- dichlorophenol under visible light irradiation. It exhibited better photocatalytic efficiency of Pd-Sparteine-α-Fe2O3 was much higher than that of pure iron oxide nanoparticles. High yield and low reaction time of this catalyst were indicated that Pd-Sparteine-α -Fe2O3 could be a promising catalyst for direct photocatalyst applications.
- Quantum chemical study of Hydroxychloroquine and Chloroquine drugs used as
a treatment of COVID-19
Abstract: Two drugs have been authorized by the Algerian health Ministry to be used in Algeria to treat coronavirus disease 2019 (COVID-19) patients, once is Hydroxychloroquine (HCQ) and the other is Chloroquine (CQ). These drugs have been theoretically studied in order to know their active sites, vibrational and electronic properties using Density Functional Theory (DFT) at the B3LYP/6-31G (d.p) level. The optimized molecular structures, the vibrational spectra, the HOMO and LUMO properties, dipole moments, Molecular Electrostatic Potentials (MEP) and atomic charges are calculated. In addition, the reactivity of drug molecules has been discussed calculating some descriptors such as energy gap, hardness, local softness, electronegativity and electrophilicity.
- The Performance Enhancement of Paraffin as a PCM During the Solidification
Process: Utilization of Graphene and Metal Oxide Nanoparticles
Abstract: The substitution of fossil fuels with renewable energies is a meaningful way to mitigate global warming and air pollution. Phase change materials could store and release a high amount of energy. Solidification phenomenon is an essential factor that should be considered for choosing phase change materials (PCMs). In this work, attempts have been made to improve the thermo-physical properties of paraffin as a PCM during the solidification process. 1-3 wt.% of Al2O3, CuO, TiO2 and graphene nanoparticles were used during the solidification process. No reports had yet been made on the effect of graphene nanoparticles versus metal oxide nanoparticles on the thermal properties of nanoparticle-enhanced phase change materials (NEPCMs). The DSC, TGA, SEM, and FT-IR analysis was done to investigate the transition temperature, nanoparticles distribution, and nanocomposites morphology, respectively. It was seen that the addition of nanoparticles could effectively increase the thermal conductivities of paraffin. The maximum and minimum increases were in thermal conductivities were recorded in samples with 3wt.% of graphene and 1wt.% of TiO2. The results showed that selecting suitable nanocomposites depended on various parameters, such as the type of nanoparticles and the weight percentage of nanoparticles. The PCM nanocomposites can be used to control the thermal management of different systems. The results can be applied in thermal design and management concepts, especially in the solidification process.
- Immobilized copper complex on biodegradable cellulose: Catalytic
application for the green synthesis of 2H-indazolo[1,2-b]phthalazine
trione derivatives and synthesis of CuO nanoparticles
Abstract: An immobilized copper (II) complex on micro cellulose (Cell-DABCO-Cu) was synthesized and characterized by FT-IR, TGA and SEM. The catalytic activity of Cell-DABCO-Cu was evaluated as a recoverable and green catalyst for four-component synthesis of 2H-indazolo[1,2-b]phthalazine trione derivatives in solvent free condition. The notable advantages of this procedure include excellent yields, short experimental time, and easy preparation of the catalyst. The feature of this work is using of Cell-DABCO-Cu as a starting material to prepare single phase CuO nanoparticles (CuO NPs) via a solid-state decomposition procedure. The CuO nanoparticles with average size of 40 nm were obtained by the direct calcination of Cell-DABCO-Cu.
- Computational and Experimental Study on the Interaction of Terbium(III)
and Ytterbium(III) Complexes Containing 1,10-phenanthroline with Bovine
Serum Albumin
Abstract: In this work, the interaction of two synthesized complexes [Tb(phen)2Cl3.OH2] and [Yb(phen)2Cl3.OH2] (phen is 1,10-phenanthroline) with bovine serum albumin (BSA) were studied by UV-Vis, fluorescence, and molecular docking examinations. The experimental data indicated that these lanthanide complexes have a high binding affinity with BSA by effectively quenched the fluorescence of BSA via the static mechanism. The binding parameters, the type of interaction, the value of resonance energy transfer, and the binding distance between complexes and BSA were estimated from the analysis of fluorescence measurements and Förster theory. The thermodynamic parameters suggested that van der Waals interactions and hydrogen bonds play an important role in the binding mechanism. While the energy transfer from BSA molecules to these complexes occurs with high probability, the binding constants showed that the binding affinity ranked in the order Tb-complex > Yb-complex that has been related to the radius of Ln3+ ion. Also, the results of competitive experiments and molecular docking calculations assessed the microenvironment residues around the bound mentioned complexes and represent site 3 of BSA, located in subdomain IB, as the most probable binding site for these complexes. The computational results kept in good agreement with experimental data.
- The Simple Method of Synthesizing Calcite and Aragonite from Indonesian
Limestone
Abstract: Precipitated CaCO3 (PCC) with calcite and aragonite phases have been successfully synthesized using natural limestone. Synthesis of PCC was carried out by the simple method of carbonation using slurry Ca(OH)2 with variation of CO2 gas flow rate at room temperature and variation of temperatures at a constant CO2 gas flow rate. The raw material used is a very high purity Madura Island limestone. The PCC product were characterized by X-Ray Diffraction (XRD), Fourier Transform Infra Red (FTIR) and Scanning Electron Microscope (SEM). PCC on CO2 gas flow variation produced the same phase, a calcite with characteristic of 2θ = 29.23° (104), rhombohedral cubic morphology, and a wavenumber of 712 cm-1 as displayed from the FTIR spectra. The mixture of aragonite and calcite phase was observed in PCC products with temperature variations of 60 - 90°C. The characteristic aragonite was observed at 2θ = 26.2° with needle-like morphology. The highest fraction of aragonite was at temperature of 60°C at 71.35%.
- Continuous purification of phosphoric acid in a microchannel
Abstract: Solvent extraction is an economically efficient method widely used in the purification of wet phosphoric acid. In this study, microchannel was applied to promote mixing and purification of phosphoric acid during continuous production. For this aim, liquid-liquid extraction was conducted to purify phosphoric acid via methyl isobutyl ketone/tri-butyl phosphate mixtures. Additionally, the Box-Behnken experimental design method was used to survey the liquid-liquid extraction process. The effect of various operational parameters such as solvent concentration (45–65 %wt.), temperature (18-28˚C) and organic/aqueous phase ratio (2:1–6:1) at a constant flow rate of 70 ml/l was examined. Experimental results indicated that the microchannel at the residence time of 6.85 min could promote the extraction percentage of and sulfate removal more than 98% and 60%, respectively, compared to the batch extractor.
- Material Selection and Manufacturing of Halogen Based Headlamp for
Two-Wheeler Vehicle Technologies
Abstract: In the plastic industry, distinctive handling hardware like expulsion, infusion trim, Calendaring, and thermoforming are utilized to fabricate various products. This equipment is fundamentally the improvement of Standard Injection Molding in which Injection Molding is significant. This procedure is utilized for the assembling of the hollow section part and the part with thin wall thickness. This research aimed to develop a halogen-based Headlamp for a two-wheeler vehicle. The essential objective of an automotive headlight is to enhance safety and protection in low light and poor climate conditions. It is the first time that a halogen-based headlamp for a two-wheeler vehicle has been created for the first time in Pakistan. The product in our project consists of three major components, reflector, halogen bulb, and lens. Material selection and processing were the two major tasks in this project. The product was manufactured through injection molding, a high vacuum metallization process, and then finally assembling of parts. To determine the quality of the product, six tests were performed according to Japanese standard JIS-D5500.
- Influence of desamerization on the quality of a jam based on grapefruit
Abstract: This work consists of studying the influence of the desamerization of the albedo on the composition, the antioxidant potential and the sensorial quality of the jam, based on the grapefruit. Salt, heat and water are considered as driving elements in the operation of desamerization process. The desamerization was carried out by different concentrations of NaCl relative to the fresh weight of the fruit (0.3125%, 0.625%, 1.25% 2.5% and 5 %).The result of the various analyzes show that the desamerization does not influence the rate of sugars and pectins, decreases the titratable acidity and the protein contents and increases the ash contents. With regard to antioxidants, the results show that desamerization decreases vitamin C levels, carotenoids and phenolic compounds. Concerning the sensory analysis of the jams, the results show that the salt significantly reduces the bitterness of the jams. The hedonic analysis shows that the tasters preferred significantly the desamerized jam NaCl 5% to all the other samples.
- Fluorescence determination of acrylamide in potato chips based on P540 and
P503 fluorescent reagents
Abstract: Acrylamide is one of the potential environmental public health problems, resulting from its increased accumulation in the process of cooking foods content high level of carbohydrates that are fried or cooked at high temperatures. So, developing a precise and sensitive analytical method for detecting and determining acrylamide in foods is absolutely necessary and inevitable. Gas chromatography (GC) and liquid chromatography (LC) are two main laboratory techniques for acrylamide determination. In this study, we tried to use a cheaper, faster, accurately method for measuring acrylamide in real food samples. P540 and P503 were used as fluorescent reagent to detect the concentration of acrylamide in potato chips samples from 4 companies. Fluorescence spectroscopy was used in this work. The results obtained for the detection of acrylamide in comparison with the HPLC-MS method showed that there is an acceptable overlap between the fluorescence spectroscopy and HPLC method. The amount of acrylamide in four potato chips samples, obtained from the market in Tehran city, was determined using the proposed method. The optimum values of different parameters, were determined. Comparison between two methods, HPLC-MS and fluorescence spectroscopy were also described. The figures of merit for the proposed method were at the ideal range. The developed methods showed a high correlation coefficient (R2= 0.991). According to the results of the fluorescence emission spectroscopy and its comparison with HPLC-MS, performance and reliability of proposed method as a simple, efficient and rapid method with reduction of cost and time for determining acrylamide in potato chip samples were demonstrated.
- Deep eutectic solvents as an efficient solvent system determination the
volatile compounds with microextraction
Abstract: In the present work, the Headspace-solid phase microextraction (HS-SDME) process was established utilizing a novel version of Deep-eutectic-solvents (DESs) for extracting and preconcentrating essential oils in plant followed by GC-FID determination. DESs seem to be a cost-effective and attractive alternative for the usage of ionic solvents in biotransformation. DESs are usually developed through gentle warming and stirring of two (low-cost and bio-based) salts. DESs have several superiority over ionic liquids such as their ease of preparation, low production cost and permits large scale applications. HS-SDMEwas made in the current research in order to extract volatile compounds by the use of deep eutectic solvents (DESs) serving as extraction solvents. HS-SDME was constructed as a solvent-minimized extraction method. However, there are a rare number of studies investigating the deep eutectic solvents (DESs) applications to the HS-SDME of bioactive compounds. Deep eutectic solvents, created by mixing choline chloride (ChCl) and p-Chlorophenol at varying ratios, were utilized for extracting essential oils from Echinophora platyloba DC via HS-SDME in the present study. Afterward, headspace single-drop micro-extraction (HS–SDME) was conducted, being connected to gas chromatography. HS-SDME is a quick and simple method in comparison with heat reflux extraction. In addition, it is possible to use DESs in HS-SDME for extracting various volatile compounds.
- Adsorption of Mercury by Pterocarpus Anglolensis: Study on Adsorption
Isotherms and Kinetics
Abstract: The efficiency of Pterocarpus Anglolensis sawdust, an abundantly available waste product of the timber industry, capacity as an adsorbent for mercury was investigated. A series of batch experiments was carried out with experimental conditions of metal concentration, adsorbent concentration, pH and contact time being differed. The concentration of the metal ion was deduced using spectrophotometric means. The adsorption efficiency was found to be pH dependent with pH 4 being the optimum. 90 minutes was found to be the equilibrium time with particle size range 90-124 μm being the most efficient. Maximum adsorption of mercury was at 80.33 %. The data were best modelled using Freundlich and Dubinin-Radushkevich isotherms giving Kf value of 0.0002171. Theoretical isotherm saturation capacity obtained was 14.577 μg/g and mean free energy of 40.82 kJ/mol.
- Removal of Phenol by Expanded Bed Airlift Loop Reactor
Abstract: The exaggerated release of industrial wastes especially those containing phenol into the environment led to the contamination of both surface and groundwater supplies. In present work a synergistic and combined system technique between three operations, adsorption of phenol via (rice husk or granular activated carbon GAC as adsorbents) together with stripping by airflow and advance oxidation via hydrogen peroxide as the oxidation agent, to evaluate the possibility of using a proposed new design for internal airlift loop reactor for removing the phenol from wastewater. The experiments were set up in a cylindrical Perspex column consisted of a transparent outer column having a 15 cm inside diameter and 150 cm height that included an internal draught tube of 7.5 cm and extending vertically to 120 cm top contains a bed having a dimension (7.5 x 30 cm) filled with adsorbent materials (rice husk, granular activated carbon GAC) and a volume capacity 25 liters. The experiments were conducted under the influence of both of the following variables air flow rate(2-20) (L/min), treatment time(5-60 min), the molar ratio of hydrogen peroxide to phenol,(1:10, 1:15 and 1:20)). The results showed the success of the proposed design with obtaining a removal efficiency (83%),( 81%)when using GAC and the rice husk as adsorbent materials respectively, with minimum remediation time 60 minutes, airflow rate of 18 L/min, and molar ratio(20) hydrogen peroxide to phenol. This study demonstrated that the proposed synergistic system could be utilized for the remediation of contaminated aqueous systems.
- Simultaneous Removal of Pb2+ and Cu2+ by SBA-15/di-urea as a Nano
Adsorbent
Abstract: In this study, potential of SBA-15/di-urea nanoporous silica compound for removal of Pb2+ and Cu2+ ions was investigated. Presence of organic groups in the silica framework of SBA-15/di-urea was demonstrated by FTIR spectrum. The functionalized product showed the BET surface area 518 m2g-1 and pore diameter 6.5 nm, based on adsorption-desorption of N2 at 77 K. SEM revealed a rod-shaped morphology and TEM image showed an ordered array of 2D hexagonal mesoporous SBA-15. The ions in the samples were identified by flame atomic absorption spectrometry. The effect of adsorbent amount, contact time, metal concentration, pH and presence of other metals on removal efficiency has been studied. Simultaneous removal of Pb2+ and Cu2+ ions from 20 mL of the sample solution containing 60 μg of each ion were completely done at pH greater than 5.0 after stirring for 15 minutes. Langmuir, Freundlich and Temkin adsorption isotherms were evaluated for both adsorbents and it was determinate that the data fitted well to the Langmuir model (R2 0.98). The maximum capacity of the adsorbent was found to be 147.0 ± 0.6 mg and 77.0 ± 0.5 mg of Pb2+ and Cu2+ ions/g SBA-15/di-urea, respectively. The lowest amount of 3M nitric acid for stripping the target species from adsorbent was determined as 20 mL. The application of this methodology for real sample was tested by Industrial wastewater sample
- Removal of Ni(II) ions from wastewater by raw and modified plant wastes as
adsorbents: A review
Abstract: Adsorption may be used to process significant metal particles in contaminated wastewater by various methods. The authors looked at various adsorbents for the expulsion of Ni(II) particles from an aquatic environment by different researchers. This paper aims to gather scattered open knowledge on a large variety of potentially persuasive adsorbents for the removal of Ni(II) particles. The present work on the usage of nickel by various natural/modified adsorbents was studied profoundly, for example, natural/modified agricultural waste, agricultural activated carbon, algae, fungal and, aquatic plant biomasses. This performance was assessed for removal efficiency and the sorbent capacity of used natural/waste materials in the system processes. Isotherm and kinetic studies results were obtained from pH solution equilibrium contact time, adsorbent dose, initial metal concentration, and temperature of various adsorbents toward the Ni(II) particles to be examined. A documented analysis of reputed published papers revealed that industrial solid waste products, natural materials, and biosorbents have extraordinary Ni (II) adsorption ability from wastewater.
- Removal of methyl green dye from aqueous solutions using activated carbon
derived from cryogenic crushed waste tires
Abstract: Activated carbon obtained from cryogenic crushing of used tire prepared and characterized previously was used as an adsorbent for the removal of cationic dye “methyl green dye MG” from an aqueous solution. Batch adsorption studies were carried as a function of varying parameters of the system such as initial solution pH, adsorbent dosage, initial dye concentration, and temperature. The experimental data were fitted using Langmuir, Freundlich, Dubinin-Radushkevich, and Temkin isotherm models. The Langmuir isotherm model fitted well the obtained experimental data. The maximum adsorption capacity of methyl green dye at pH 7 was found to be 71.43 mg/g. The results of kinetics study indicated that the experimental data are fitted to Pseudo-first order model. The thermodynamic properties like ∆G, ∆H, and ∆S were estimated for the adsorption processes and indicated that this latter was exothermic, spontaneous, and favorable. The developed activated carbon might be used in a favorably manner for removing methyl green from aqueous solution.
- Statistical Analysis of the Effects of Aluminum Oxide (Al2O3)
Nanoparticle, TBAC and APG on Storage Capacity of CO2 Hydrate Formation
Abstract: In this study, the effect of various concentrations of alkyl polyglycoside (APG), aluminum oxide nanoparticles (Al2O3), and tetra-n-butyl ammonium chloride (TBAC) on the storage capacity of CO2 hydrate formation are investigated. For this aim, a laboratory system is developed. The experiments are carried out in the pressure range of 25 to 35 bar and the temperature range of 275.15 K to 279.15 K. The Experimental results showed that by increasing the system pressure at constant temperature, the storage capacity increased by 48% in average. Decreasing the system temperature at constant pressure increased the storage capacity by 23% in average. Adding APG to the system at constant temperature and pressure increases the storage capacity by 75% in average, while adding nanoparticles of aluminum oxide increases the storage capacity by 5% and TBAC 38% in average. For statistical analysis of laboratory data, Design Expert software and Response Surface test design method and Quadratic model are employed and a mathematical relationship is developed with R2 = 0.9987 to estimate CO2 storage capacity in hydrates. The optimum amount of storage capacity equal to 137.476 has been reached at 34.558 bar, 276.085 K, 2.825 Wt% of TBAC, 956.733 ppm APG, 2.436 Wt % Al2O3.
- Effect of different kinds of hydrate promoters on the kinetics of methane
hydrate formation in methane-water-oil system
Abstract: In this work, the effect of hydrate promoters on methane hydrate formation in methane-water-oil system with different initial watercuts from 20 vol% to 100 vol% were studied. For comparison, four promoters based on different promotion mechanisms, sodium dodecyl sulfate (SDS), L-leucine (L-l), tetrabutylammonium bromide (TBAB) and polysorbate 80 (Tween 80) were used. The experimental results show that four hydrate promoters did inhibit the nucleation of methane hydrate in 100 vol% watercut system, but the growth kinetic of methane hydrate was effectively improved compared with the system without hydrate promoter. The induction time decreasesd with the increase of initial watercut under the same concentration of hydrate promoter for the methane-water-oil system, and the total methane consumption used for hydrate formation gradually increased with increasing initial watercut (except Tween80). But the current results also show significant improvement in normalized gas consumption per unit water content with the increase of oil phase volume fraction due to that upon addition of oil phase the methane dissolution and mass transfer rate in the methane-water-oil system improves further, meaning that the formation rate of methane hydrate is enhanced. Because of the emulsifying property of Tween 80, the emulsion structure of the systems within Tween 80 hindered the hydrate growth process to some extent. Out of the four hydrate promoters used in this study, SDS was found to be most effective in enhancing the formation kinetic of methane hydrate as well as reducing the induction time in methane-water-oil system under similar conditions.
- On the Calculation of the Virial Coefficients and low Pressure
Joule-Thomson Effect for Refrigerant Fluids Using Two Equation of State
Models
Abstract: In this paper, we calculate virial coefficients and Joule-Thomson effect at low pressure for refrigerants fluids in order to evaluate the performance of two models of Equations of State (EOS). The studied refrigerants are R123, R124, R143a and R152a. The investigated EOSs are van der Waals type consist of van der Waals (vdW), Redlich-Kwong (RK), Soave- Redlich-Kwong (SRK) and Peng-Robinson (PR). In our work, we use Dieterici model of EOS consist of Dieterici (D) and Dieterici-Carnahan-Starling (DCS). The obtained results show that all EOSs predict the qualitative behavior of the second virial coefficient of refrigerants in wide range temperature but, cannot provide the qualitative behavior of the third virial coefficient of refrigerants in in comparing with experimental data. Quantitatively, the EOSs on the basis of vdW model present good results in wide range of temperatures. Both models of equations of state can also predict qualitative behavior of changing the low pressure J-T coefficient with respect to temperature. Our study shows that the EOSs on the basis of vdW model, especially PR, present better results than the other model in wide range of temperatures.
- Liquid + liquid equilibria of the ternary system water + glycerol +
1-butanol system: experimental data and modeling
Abstract: In this study, solubility and tie-line data of ternary system water + glycerol + 1-butanol were determined at 293.2, 298.2 and 303.2 K and atmospheric pressure. This thermodynamic system is relevant for the production and purification of biofuels. Phase equilibrium data have been determined by cloud-point titration method and the tie-lines were obtained by correlating the refractive index of the binodal curves as a function of mixture composition. All measured LLE data were modeled by UNIQUAC and NRTL activity coefficient equations obtaining a satisfactory accuracy with modeling errors lower than 0.4%. Binary interaction parameters of tested thermodynamic models were estimated to predict the value of tie lines using a hybrid bio-inspired swarm intelligence optimization algorithm, that is, MAKHA without and with closure equation. This hybrid method was reliable to solve the global optimization problem for the binary interaction parameter identification of this ternary system. Results of this paper provide useful information for the design and modeling of industrial units for glycerol recovery, which is a relevant industrial feedstock.
- Estimating Aqueous Nanofluids Viscosity Via GEP Modeling: Correlation
Development and Data Assessment
Abstract: This paper focuses on developing a new method that represents user-accessible correlation for estimation of water-based nanofluids viscosity. For this, an evolutionary algorithm, namely Gene Expression Programming (GEP), was adapted based on a wide selection of literature published databanks including 819 water-based nanofluids viscosity points. The developed model utilized the base fluid viscosity as well as volume fraction and size of the nanoparticles as the inputs of the model. Several statistical parameters integrated with graphical plots were employed in order to assess the accuracy of the proposed GEP-based model. Results of the evaluation demonstrate fairly enough accuracy of the developed model with statistical parameters of AARD%=11.7913, RMSE=0.3567, and SD=0.1851. Furthermore, the trend analysis indicates that the GEP calculated points satisfactorily follow the trend of the nanofluid viscosity variation as a function of different model inputs. To provide more verification, the proposed GEP model was compared with some literature theoretical and empirical correlations leading to the supremacy of the developed model here. The applied sensitivity analysis reveals that the highest impact value is assigned to the volume fraction of the nanoparticle. Moreover, the outliers detection by Williams’ technique illustrates that about 96.5% of the GEP estimates are in the applicability domain resulting in the validity of the proposed model in this study. At last, the results of this study demonstrate that the new method here outperforms other literature published correlations from the standpoint of accuracy and reliability.
- Determination of the Minimum Miscible Pressure of the Supercritical Carbon
Dioxide and the Formation Oil System by the Pendant Drop Method
Abstract: Carbon dioxide miscible displacement plays an important role in the field of miscible displacement for enhanced oil recovery. However, there is a very important relationship between the formation of miscible displacement and the minimum miscible pressure. The pendant drop method in the interfacial tension method was firstly used to predict the minimum miscible pressure of the supercritical carbon dioxide and the formation oil of the test area oilfield. Under the condition of the simulated reservoir temperature 111.5 °C, the interfacial tension of the supercritical carbon dioxide and the formation oil system was tested experimentally by using formation oil samples of the test area oilfield. The range of test pressure was from 10.06 MPa to 28.57 MPa. Beside, the relation curve of the test pressure and the interfacial tension was drawn. The results show that under the reservoir temperature, the interfacial tension between the supercritical carbon dioxide and the formation oil shows approximately linear downward trend with increasing the test pressure. The mathematical expression was obtained by the linear regression analysis. According to the extrapolation, the vanishing point of the interfacial tension was obtained. Then the minimum miscible pressure of the supercritical carbon dioxide and the formation oil system was determined. The actual test was carried out to verify the result by the pendant drop method. Finally, the minimum miscible pressure of the supercritical carbon dioxide and the formation oil system of the test area oilfield was determined to be 29.4 MPa.
- Time scale analysis for prediction of Nusselt number of nanofluids flowing
through straight tubes: An experimental study.
Abstract: In view of anomalous heat transport behavior in nanofluids, a number of possible mechanisms suggested by various authors to explain the thermal conductivity and heat transfer coefficient enhancement lacks unanimity. Hence, the aim of this research article is to explore convective heat transfer enhancement mechanisms by correlating it with observed experimental data of nanofluids. The analysis is carried out by comparing the order of magnitude of different diffusion mechanisms for different types of nanofluid systems. Four different types of nanofluids, Al2O3/EG-W (0.6, 0.9, 1.2 and 1.5 vol.%.), Al2O3/PG-W (1, 1.5, 2 and 2.5 vol.%.), CuO/PG-W (0.25, 0.5, 0.75 and 1 vol.%) and MgO/PG-W (0.3 and 0.66 vol.%) have been studied in this research. A generalized mechanism based correlation have been proposed to predict the Nusselt number for these nanofluids, for a flow through straight tube under laminar conditions. Results showed that the Brownian motion is very slow in comparison to nano convection diffusion and heat diffusion. The proposed model predicted the combined data for all the nanofluids studied well within a range of ±5%. Statistical error of proposed model were also calculated. Data of other authors was also validated using the proposed correlation, and parity plot showed that the correlation predicted the data well within a range of ±15%.
- EXPERIMENTAL INVESTIGATION AND PARAMETER ANALYSIS OF SOLAR STILL WITH THE
DIFFERENT WICK MATERIALS
Abstract: This paper aims to produce freshwater from saline water with the help of solar still. Different solar wick materials still absorb the sunlight and convert the heat energy, such as black sheer mesh fabric, light black cotton fabric, light jute fabric, black velvet fabric, and 4 mm thick sponge sheet. The wick materials sheets were wholly immersed into the saline water covering the total still basin area. The net basin horizontal active area of the solar still is 0.48 m², and the glass cover’s tilted angle was fixed at 36º. From this arrangement, it has been found that by the use of various wick materials, the productivity rate differs from each other, and among these wick materials, light black cotton is the most effective wick material for solar still productivity increment. The pH value measures the final quality of the freshwater.
- Passive thermal management of a lithium-ion battery using carbon fiber
loaded phase change material: comparison and optimization
Abstract: Phase change materials (PCMs) are currently used for many heat management applications. However, the heat transfer performance of PCMs is limited by their low thermal diffusivities. This is a critical issue for high heat flux applications, such as in thermal management of lithium-ion (Li-ion) batteries. The present work aims at the study of heat transfer enhancement in a cylindrical Li-ion battery thermal management system consisting of a PCM (paraffin) loaded with randomly distributed and radially oriented carbon fibers. The system was simulated numerically under various cooling conditions, including naturally convecting air, in the presence of pure paraffin, and in the presence of carbon fiber loaded paraffin. The results for orderly arranged carbon fibers were compared with those of random distribution. Numerical results indicated that better battery thermal management can be achieved for the radially distributed carbon fiber arrangement in the PCM. The advantage of radial over random distributions can be due to the constant, uniform, and non-agglomerating distribution of carbon fibers under which thermo-physical properties of carbon fibers are better realized in the composite medium. The presence of carbon fibers with thermal conductivity of k=50W/m K in the PCM has caused a more uniform temperature profiles in the radial direction because of the improved thermal conductivities. The results of this research can be used as a guideline for designing battery thermal management system.
- Simulation and Capacity Evaluation of Refinery Flare System and
Comparative Analysis of Carbon Capture Technologies
Abstract: In refinery flare system is the last defense line for controlling over-pressurization of process vessels. Mostly power failure is the worst contingency in the refinery, and the flare capacity is evaluated for this case. The data of pressure safety vessels (PSVs), header network, knockout drums, flare stack and flare tip is to utilize for simulating the flare system of oil refinery complex (ORC-II). Carbon dioxide (CO2) is a significant benefactor in the global warming stances a severe hazard to environment. The procedure was conveyed using 30 wt. % monoethanolamine (MEA) dissolvable and Hollow-fiber cellulose acetic membrane framework. This research consists of two sections. The initial segment the capacity evaluation of the flare framework was finished utilizing Aspen Flare System Analyzer V8.4 and rating of flare framework was conveyed in which to break down the necessary parameters like Mach number and back weight in the system and the adjustments in the flare framework were made as per API 520. In the second part chemical absorption and membrane separation innovations were looked at for post-combustion carbon catch. The research focuses on conveying relative investigation of above-expressed methods for flow rate of vent gas runs between 1 to 200 MMSCFD. The goal is to accomplish 90% recuperation of CO2 with carbon decrease from 10.66 mole % to 2 mole %. The absorption technique is simulated by ASPEN HYSYS V8.4 and program for membrane framework is created by connecting values from ASPEN HYSYS to Microsoft EXCEL. For membrane separation the operating expense is seen as lower than absorption process, yet from the results it was concluded that the absorption technique is superior to membrane technique until the problems concerning degradation of membrane and high capital expense would be settled.
- Rheological study of a Pickering emulsion stabilized by Algerian clay
particles
Abstract: A Pickering Oil/Water (O/W) emulsion was formulated based on Algerian bentonite particles with small amounts of synthetic surfactant ranging between 0.01 and 0.05 %.A rheological study was carried out on the emulsions studied after 18 months of aging using a parallel plate geometry. The rheological study, under variable shear, has shown that the viscous behavior of these emulsions is of structural type, with the presence of two Newtonian regions at low and high shear. The oscillatory test revealed that emulsions have the character like a viscoelastic gel wich is practically insensitive to frequency decreasing sweep and therefore potentially stable over time. Results showed that 7% of bentonite, and 0.015% of cationic surfactant (cetyltrimethylammonium bromide) are necessary to obtain a Pickering emulsion with an adequate rheological behavior for a cutaneous application.
- Design, synthesis, biological evaluation and docking study of novel
4-anilinoquinazolines derivatives as anticancer agents
Abstract: Epidermal Growth Factor Receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) as appropriate targets for cancer therapy have recently made noteworthy field since the introduction of vadetanib as a dual inhibitor of VEGFR and EGFR tyrosine kinases (TKIs). In this study, twelve quinazoline derivatives were designed, synthesized, and evaluated for their cytotoxicity on A431 (human carcinoma cell) as well as HU02 (Foreskin fibroblast) cell lines by MTT assay. The binding mode of the most potent compound (8a) with EGFR and VEGFR2 was studied using molecular docking. Most of the compounds showed significant inhibition on the growth of A431 cells at the concentration lower than 100 µM. The compound 8a bearing diethylamine along with 4-bromo-2-fluoroaniline exhibited the best cytotoxic activity (IC50=2.62 μM) compared to erlotinib and vandetanib as positive controls. Synthesized compounds did not indicate significant cyttoxicity against HU02 cell line Quinazoline N1 of 8a depicted the shorter hydrogen bonding distance with the residue Met-769 of EGFR (1.719 Å) and Cys-919 of VEGFR (2.809 Å) in comparison with vandetanib which was consistent with higher cytotoxicity of this compound. Higher potency of 8a may be put down to the flexibility of diethylamine and its higher lipophilicity as well as lower steric hindrance of this substituent.
- Zeolite imidazolate framework nanocrystals electrodeposited on stainless
steel fiber for determination of polycyclic aromatic hydrocarbons
Abstract: New solid phase microextraction (SPME) coating was made by electrodeposition of zeolite imidazolate framework (ZIF-67) nanocrystals with the aid of polyaniline (PANI) on steel fiber. The SPME fiber was used to extract four polycyclic aromatic hydrocarbons (PAHs) from headspace (HS) of tea infusions and determined by gas chromatography coupled with flame ionization detector (GC-FID). The coating of the SPME fiber was characterized by Fourier transformed infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Vital parameters affecting extraction performance, including desorption conditions, salt concentration, extraction time, and temperature, have been evaluated and optimized. The validated method was specific for the PAHs analysis, with the limit of detection (LOD) as low as 20.0 to 50.0 ng/L. The linear range was relevant to 70.0-180.0 ng/L with relative standard deviation (RSD) % of less than 12.8. The factor of enrichment was found to be 446.7-808.8. The synthesized coating was shown to be thermally and chemically stable. The recommended approach was successfully applied to quantify PAHs in some frequent tea infusions in the market. The fiber coating of ZIF-67 can be easily made and applied efficiently to detect PAHs pollution in the environment and food products.
- Investigation of Thermophysical Properties of IoNanofluids Containing
Multi-Walled Carbon Nanotubes and Graphene
Abstract: Thermophysical properties of base ionic liquid (C10H19F6N2P) (IL) and IoNanofluids (INF) containing different contents of (0.05, 0.1, and 0.5 wt%) multiwalled carbon nanotubes (MWCNTs) and Graphene (Gr) were measured experimentally. INF exhibited augmentation in thermal conductivity, viscosity, and heat capacity respect to the base fluid. Maximum thermal conductivity breakthrough was detected at 39%, 48% of MWCNT-IL and 0.5wt% of Gr-IL, respectively. Eventually, the experimental viscosity and thermal conductivity data were fitted with the existing theoretical models. The findings highlighted that the viscosity of MWCNTs-IL and Gr-IL was in unison with particles aggregation effect (Krieger-Dougherty model) and the both INF effective thermal conductivity are prognosticated by interfacial layer approach with sufficient accuracy.
- Experimental & Theoretical investigation of Glucose – Graphene Hybrid
for increasing the Natural Gas Storage
Abstract: Several categories are usual ways for natural gas storage: Compressed Natural Gas (CNG), Adsorbed Natural Gas (ANG), and liquefied gas methods. The ANG technologies allow the natural gases to be absorbed via porous materials at high temperatures and low pressures, around 500 psig (3.5 MPa). Via an accurate comparison, it has been exhibited those gases can be stored in a CNG tank at approximately 3,500 psig. Therefore, the ANG system appears to be prospective for any future activities. In this study, Glucose–Graphene hybrid based materials with hierarchical structures, tunable surfaces, chemical doping, and functionalization were simulated for gases with γ=1.41 such as (H2, N2, O2) and γ=1.33 for (CH4, CO2, NH3, NO2, H2S, SO2) and γ=1.67 for (He, Ne) sorption, storage, and separation. The scope of this work is to produce a new Nano-adsorbent, i.e., Hybrid -Glucose-Graphene, which can be introduced as a new candidate for that gas storage.
- Effect of nitrogen doping and acene cores elongation on charge transport
and electronic nature of organic semiconductor materials: A DFT study
Abstract: With the intention to tune the charge transport nature of preliminary 4,6-di(thiophen-2-yl)pyrimidine (DTP) structure, six novel V-shaped organic semiconductor compounds were designed by nitrogen doping and acene moieties elongation. Initially, the nitrogen atoms were doped in DTP to design 4,6-bis-thiazol-2-yl-pyrimidine (1). Moreover, by ℼ-bridge elongation strategy, 4,6-bis-benzo[b]thiazol-2-yl-pyrimidine (2), 4,6-bis(naphthothiazol-2-yl)pyrimidine (3), 4,6-bis(anthracenothiazol-2-yl)pyrimidine (4), 4,6-bis(tetracenothiazol-2-yl)pyrimidine (5), and 4,6-bis(pentacenothiazol-2-yl)pyrimidine (6) were designed by substituting various oligocenes at both ends. The ground as well as excited state structures were optimized using density functional theory (DFT) and time-dependent DFT at B3LYP/6-31G** and TD-B3LYP/6-31G** levels, correspondingly. We explored their frontier molecular orbitals, electron injection aptitude, photo-stability, ionization energies (IE), electron affinity (EA), and reorganization energies. The bridge elongation significantly elevate the EA while reduce the IE which would results to decrease the injection barrier for electron and hole transport. Furthermore, acene cores elongation expressively decrease the hole and electron reorganization energies as compared to frequently used materials pentacene and tris(8-hydroxyquinolinato)aluminum (mer-Alq3) which revealed that newly designed materials would be proficient to be used in p- and/or n-type semiconductor devices.
- Computational study of the mechanism and reactivity of -himachalene in
presence of carbenes using DFT
Abstract: The reactivity of the bicyclic sesquiterpene β-himachalene which considered one of the main constituents of the essential oil of the Atlas cedar (Cedrus atlantica) and its derivatives has been studied extensively, in order to prepare new biological products. The title compound, C17H26Br2 was synthesized from the β-himachalene with (_.^.)〖CBr〗_2 , in dichloromethane and with (_.^.)〖CH〗_2 cycloaddition reaction, in diethyl ether, respectively. Density functional theory calculations at the B3LYP/6-311+G(d,p) computational level account for the total chemo- and regioselectivity, in complete agreement with the experimental outcomes. Analysis of the conceptual density functional theory (DFT) indices accounts for the polar character of this reaction.
- NOVEL CYCLIC SCHIFF BASE AND ITS TRANSITION METAL COMPLEXES: SYNTHESIS,
SPECTRAL AND BIOLOGICAL INVESTIGATIONS
Abstract: 2, 5-hexanedione, 3,4-diacetyl, and ethylenediamine were condensed to obtain novel Schiff base ligand. Ni(II) and Co(II) complexes have been synthesized by reacting ligand with hydrated metal salts in a 1:10 ratio. Elemental analysis, IR, 1HNMR and mass spectrometry revealed unique structure, a cyclic decamer, of ligand and metal complexes. Synthesized compounds were screened for anti-microbial character against fungi viz. Aspergillus niger and Trichophyton rubrum and bacteria viz. Staphylococcus aureus and Klebsiella pneumoniae, using well plate diffusion method. Investigation of antiangiogenic activity was done by CAM assay using chicken eggs. Biological activities of ligand found enhanced after coordination with metal ions.
- Synthesis of new Organo-Inorgano-Clay materials based on metal ions, CTMAB
and Bentonite. Application for removal of Acid dye
Abstract: The present study focuses on the synthesis of pillared bentonites materials prepared by intercalating solutions of aluminum, chromium and iron and cetyltrimethylammonium bromide (CTMAB) into natural bentonite. Six solids were obtained and applied as adsorbents to remove acid yellow E-4G dye from aqueous solutions. Different characterization methods, such as chemical composition, X-ray diffraction and specific surface area, were used for that purpose. The efficiency of dye removal was studied as a function of pH, initial dye concentrations, contact time and temperature. The efficiency of dye removal by CTMA-Al intercalated bentonite was found higher than that of inorgano-bent, under similar conditions. The results obtained showed that the maximum adsorption capacity for dye by modified bentonite was reached within the pH range from 1 to 2. Indeed, the maximum adsorption capacity was estimated to be 385 mg/g at room temperature. The results of kinetics study regarding the removal of E-4G dye by modified bentonites was found to fit the pseudo-second-order model. Moreover, it turned out that the adsorption isotherm data obtained fit well the Freundlich model, which is not the case for the Langmuir and D-R models tested. Calculated thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic with bentonite intercalated by aluminum and iron (B-AlFe) and is exothermic in the case of inserted bentonite by cetyltrimethylammonium and chromium (B-C-AlCr).
- Preparation and characterization of Enset starch (ES) based films:
plasticized by glycerol and sorbitol
Abstract: Films were prepared using casting method from enset starch, as a filler material, glycerol & sorbitol as plasticizers at different concentrations (15, 25 and 35%). And glucose, fructose and sucrose were added to enhance flexibility. The films were characterized and compared the effect of plasticizer type (glycerol and sorbitol) and concentration some physicochemical properties of ES based films. The films were analyzed for moisture content, film density, and thickness, swelling capacity, tensile strength and percentage elongation. The study indicated that moisture content, film thickness, film density, swelling capacity, tensile strength and percentage elongation are dependent on the type of plasticizer and its concentration. Increasing the plasticizer concentration from 15 to 35 % increases moisture content, film thickness; decreases the film density, water swelling capacity and tensile strength of films, regardless of the plasticizer type used.
- Investigation of Thermal Decomposition Kinetics of Some RDX Based Material
Abstract: The aim of the current study is to compare thermal decomposition kinetics of three 1, 3, 5-trinitro-1, 3, 5-triazinane (RDX) based explosives, containing A4, H6, and PBXW-108 using TGA/DSC experimental techniques and analytical methods. The experimental part of the study performed non-isothermally at 1, 2, 5, 10, 15, and 20 °C min-1 heating rates. A complementary approach which is a combination of model free isoconversional methods and model fitting methods was carried out to achieve more accurate results for the kinetic parameters. Moreover, Arrhenius parameters were determined by non-isoconversional Kissinger’s method. The values of the self-accelerating decomposition temperature (TSADT)and the critical ignition temperature (Tb) were also calculated. The results indicated that PBXW-108, a plastic bonded explosive, in comparison to H6 and A4 has the highest pre-exponential factor and activation energy of decomposition. Moreover, TSADT and Tb of PBXW-108 are higher than those of A4 and H6. Therefore, PBXW-108 can be introduced as a safer alternative to traditional A4 and H6 explosives. According to the obtained results, the contracting area model (R2) is the best choice for describing both PBXW-108 and H6 decompositions, while the F1/3 model is the suitable one for A4.
- Unveiling the Full Potential of 2-aryl-1H-phenanthro [9,10-d] imidazoles
as Cytotoxic Agents vs AGS, HepG2 and MCF-7 Cell lines
Abstract: A few 2-aryl-1H-phenanthro [9,10-d] imidazoles were synthesized and assessed for their cytotoxicity against MCF-7, HepG2, and AGS cell lines using MTT assay. Cellular assessments showed that phenanthroimidazoles were extremely potent cytotoxic agents (sub-nanomolar IC50s). Maximum effect was recorded for para-N-phenyl acetamide containing derivative against AGS cells (IC50=0.07 nM). It was also revealed that phenanthroimidazole derivatives showed better cytotoxicity against MCF-7 and AGS cells when compared to HepG2 cells. Minimum cytotoxicity was reported for para-methylphenyl derivative within HepG2 cancer cells (IC50 7608.07 nM). Structure activity relationship studies indicated that incorporation of nitrogen/oxygen containing polar groups such as N-acetyl or nitro into para/meta positions of phenyl ring significantly enhanced the cytotoxicity against AGS cells. Similar trend was observed in meta-nitro derivatives vs MCF-7 cells. It was revealed that even the least potent compound exhibited cytotoxic activity in the range of low micromolar IC50. Results of this study proposed 2-aryl-1H-phenanthro [9,10-d] imidazoles as privileged structures for further in vivo studies.
- POLYCYCLIC AROMATIC HYDROCARBONS (PAHs) AND TRACE METALS IN SOME BRANDS OF
SAUSAGE ROLL IN THE NIGERIAN MARKET
Abstract: Background: Concentrations of PAHs and trace metals in five selected brands of sausage commonly available in the Nigerian market were determined in this study. The health risk assessment of both PAHs and trace metals were also evaluated. Methods: PAHs extraction of the sausage samples was carried out with Soxhlet extractor and clean-up of the extract was done using activated silica gel. The analysis of target analytes including the 16 priority PAHs was performed with Gas Chromatography equipped with Flame Ionization Detector (GC-FID) and the concentration of trace metals were determined using Atomic Absorption Spectrophotometry (AAS) after acid digestion of the sausage samples.Results: The amounts of Ʃ16 PAHs in sausage samples were in the range of 12.5-36.2 µg/g. All the samples investigated had concentration of Benzo (a) pyrene above 0.001 µg/g limit in processed cereal based food products stipulated by European Commission Regulation. In this study, the brands of sausages were majorly polluted with 4- and 5-ring PAHs. The concentrations (mg/Kg) of trace metals ranged as follows: Zn (1.01-71.0), Cu (ND-8.12) and Cr (ND-16.4). Cd was not detected in all the sample. Pb ranged from 2.34-13.0 mg/kg infringing the safe limit for cereals and cereal-based food products of 0.3 mg/kg and 0.05 mg/kg stipulated by FAO/WHO and European Commission, respectively. Conclusion: However, it is imperative to constantly monitor and control the concentrations of these pollutants in sausages since they are commonly consumed by Nigerian school children and youths.
- Mild steel corrosion inhibition in hydrochloric acid using cocoa pod
husk-Ficus exasperata: extract preparation optimization and
characterization
Abstract: This paper aimed at studying optimization of cocoa pod-Ficus exasperate (CP-FE) extract preparation as mild steel anticorrosive agent in hydrochloric acid solution using central composite design as optimization tool. Maximum inhibition efficiency of 95.42% was obtained at ethanol volume, extraction time, CP-FE mixing ratio and CP-FE mass of 500 ml, 48 hr, 5 and 100 g respectively. Coefficient of determination value of 0.9674 between experimental and predicted values suggested that the model developed was exact. Optimum predicted point for CP-FE extract preparation by CCD was 62.02 ml, 9.51 hr, 3.42 and 75.68 g for the ethanol volume, extraction time, CP-FE mixing ratio and CP-FE mass respectively. SEM images revealed acid attack on mild steel surface. Adsorption of CP-FE extracts on mild steel surface prevents acid attack. FTIR revealed presence of carboxyl (-COOH) and hydroxyl (-OH) functional groups. EDS revealed high iron composition on mild steel surface in the presence of CP-FE extracts. Loss of Fe2+ into free HCl solution was observed from the AAS result. Conclusively, mixed cocoa pod-Ficus exasperate extracts exhibited effective corrosion inhibitory attributes for mild steel in HCl solution.
- Application of axial velocity profile in order to develop residence time
distribution (RTD) for different laminar and turbulent flows
Abstract: The famous definition of RTD is based on the volumetric flow rate but is experimentally defined using the tracer concentration. These different views have erroneously limited the application of the velocity profile for RTD evaluation to the laminar flows. In this work, a more general sense of RTD is introduced and it has been emphasized that regardless of the dispersion behavior, the velocity profile is sufficient in order to obtain the corresponding RTD. A general algorithm for RTD evaluation using axial velocity profile is developed and the relations were derived for different systems. In addition, the corresponding velocity profiles to the famous RTD models were numerically evaluated. It has been shown that the final forms are consistent compared to the previous relations for laminar flows.
- Dispersive Solid Phase Extraction Combined by Dispersive Liquid- Liquid
Microextraction for Preconcentration of Brilliant Green from Fish and
Seawater Samples and its Determination by Spectrophotometry
Abstract: A highly sensitive, simple and speed technique was employed for the determination of brilliant green in fish (Sphyraena jello) and seawater samples by visible spectrophotometry after its extraction and enrichment with chitosan- zinc oxide nanoparticle coupled with dispersive liquid- liquid microextraction. Ultra-trace concentrations of brilliant green were dispersed to organic phase in DLLME method after adding of dispersive solvent and chitosan- zinc oxide nanoparticles. The experimental factors such as amount of chitosan- zinc oxide nanoparticles, concentration of Triton X- 114, type of volume of extraction and dispersive solvents, extraction time, rate and time of centrifugation, volume of sample and pH were investigated to order to enhance of the extraction efficiency. Under optimum extraction condition, volume of chloroform (as extraction solvent) and methanol (as dispersive solvent) were 100.0 µL and 550.0 µL, respectively; amount of chitosan- zinc oxide nanoparticles was 15.0 mg; time of extraction was 4.0 min; rate and time of centrifugation were 3000.0 rpm and 8.0 min, respectively, volume of sample was 8.0 mL, and pH of sample solution was 4.0. After optimizing of the microextraction conditions and instrumental factors, an enrichment factor of 169.0 was achieved. The analytical curve )absorbance vs. concentration( was linear over the range 1.0-200.0 µg/L of brilliant green. The limit of detection and relative standard deviation were 0.3 µg/L and < 6.1 %, respectively. The protocol was successfully employed to the determination of brilliant green in seawater of Chabahar Bay and fish (Sphyraena jello) samples.
- Kinetics and thermodynamics of water extraction of foxtail millet
polysaccharides
Abstract: In order to understand the mechanism of the extraction process of polysaccharides from foxtail millet by hot water, the extraction was carried out for studying the kinetics and thermodynamics of extraction process. After the appropriate stirring rate and liquid material ratio was selected through preliminary experiment, the changes of polysaccharides mass concentration in the extract liquor with extraction temperature and extraction time were measured. The experimental data were fitted by the first-order model. The kinetics and thermodynamics parameters were calculated. The results showed that the appropriate stirring rate and liquid material ratio was 150 r/min, 20.0 mL/g respectively. The greater extraction rate and higher equilibrium mass concentration could be obtained under higher extraction temperature. The extraction process accorded with the first-order dynamics model. The apparent activation energy of process was 12.03 kJ/mol under study conditions. The internal diffusion coefficient was increased with increasing temperature in the range of 7.84×10-10 - 1.29×10-9 m2/min. The half-life was decreased from 25.2 min to 3.9 min as temperature increased. The Gibbs free energies were all less than zero, the enthalpy change was 31.96 kJ/mol and the entropy change was 120.3 J/(mol·K) in process. The polysaccharides extraction process was a spontaneous, endothermic and entropy increases process.
- Oil Withdrawal Technological Advancement for Multilayer Field
Abstract: The authors discuss the technology for dual pumping technology of oil-producing wells and show its advantages and shortages. It is concluded that the simultaneous-separate oil production project proposed is economically attractive due to increment in oil production, high income terms and short pay-off period even in small and depleted reservoirs. Furthermore, the potential of the proposed project is evaluated in terms of the required facilities and incremental oil production. Dual pumping technology becomes of ever-more use today, since unified well-spacing pattern envisioned for multilayer fields development and operation ensures feasibility of multiple-zone production, and, as a consequence, ramp-up of reserves recovery and oil drainage amount as well. At the same time, practicability of multiple-zone production depends on a number of fraught factors and requires thereof appropriate inventory and current status analyses to be fulfilled with regard to reserves recovery operations. As influx performance study and fluid-bearing characteristic of reservoirs are often incomplete due to field situation, the authors, therefore, follows the task to carry out an efficiency analysis of multi-zone productions based on dual completion technologies.
- Oxygen mass transfer coefficient and power consumption in a conventional
stirred-tank bioreactor using different impeller in a non-Newtonian fluid:
An experimental approach
Abstract: In this study, we investigated the power consumption and volumetric mass transfer characteristics in an un-baffled stirred-tank bioreactor using a non-Newtonian fluid and different impellers. The impellers studied were a Rushton turbine impeller, a paddle impeller, a marine impeller, a segmented impeller and, a elephant ear impeller. Studies were performed over a wide range of agitation speeds (0–2000 rpm) and aeration (0.1–0.3 vvm). The effects of superficial gas velocity, impeller speed, power input, and liquid viscosity were studied as significant factors for KLa and power input estimation. The Rushton turbine impeller was found to be the most efficient in achieving higher KLa (0.015 min-1) even at lower agitation and aeration rates compared to other impellers. The trend of KLa was found to be similar for axial flow generating impellers. Correlations were derived for all the impellers at different superficial gas velocities (Vg) and gassed power per volume (Pg/V), and a correlation coefficient R2>0.99 was achieved in all the cases. The power drawn by the impellers was tested, and maximum power consumption was observed using the Ruston impeller (198.04W), followed by the paddle impeller (152.3W). However, under aerated conditions, the power consumption was lowered by 25–35% in all the cases. The power input ratio (Pg/Po) was found to be in the range of 0.35–0.61 for all the impellers studied. The power number (Np) was estimated and the results were found to be comparable with earlier studies. Thus, the present study gives more insight into the performance of different impellers and will be helpful in process development.
- Experimental Study and Correlation for Mass Transfer Coefficient in the
Pilot Plant Multistage Column with the Presence of Molybdenum
Abstract: In the present work, multistage extraction column performance for reactive separation of molybdenum from the leach aqueous phase by using D2EHPA and TBP in kerosene was investigated by using axial diffusion model. Initially, the values of initial pH and extractant concentration were optimized on the batch experiments. The variation of volumetric overall mass transfer coefficients based on continuous phase at various operating conditions was obtained. By considering the chemical reaction conditions, the experimental data indicate that the volumetric overall mass transfer coefficients increase with an enhancement in rotor speed and continuous and dispersed phase flow rates. According to the sensitivity analysis, the rotor speed and flow rate of dispersed phase have more influence on column performance. Also, the continuous flow rate has little effect on volumetric overall mass transfer coefficients. After the steady-state condition was established, the concentration profile for the extraction of molybdenum along the column was obtained. The experimental data were studied and compared with the previous models. A new model based on dimensionless numbers was derived from the evaluation of overall mass transfer coefficients with consideration of the reactive extraction system.
- Interfacial Behavior of Aqueous Solutions of Cetyltrimethylammonium
Bromide (CTAB), Additives and Their Mixtures: The Experimental and
Modeling Study
Abstract: In the present investigation, firstly, the surface tension measurements were conducted for aqueous solutions of cetyltrimethylammonium bromide, acetonitrile, and tetrahydrofuran by using a pendant drop apparatus at the temperature of 298.15 K and ambient pressure. Then a thermodynamic model was used and successfully reproduced the surface tension values. The percent of the average absolute deviation for surface tension was 0.667. The surface tensions of mixed aqueous solutions of (cetyltrimethylammonium+additives) were measured at various concentrations. Then, the values of critical micelle concentrations were measured based on surface tension and conductivity. The percent of the average absolute deviation of the thermodynamic model was 5.05, proving that the model successfully predicts the surface tension for aqueous mixed solutions of (cetyltrimethylammonium+additives). The presence of additives decreases the surface coverage of cetyltrimethylammonium and increases the critical micelle concentration values.
- Mixed matrix membranes using SAPO-34/ APMDES / PES for carbon
dioxide/methane separation
Abstract: Among the various CO2 reduction technologies, membrane-based technologies are the most efficient and environmentally friendly process. In this study, matrix membranes of polyester sulfone (PES) mixed with zeolite were used for CO2 separation. SAPO-34 zeolite was used as a mineral filler and 3-3-aminopropyl methyl detoxysilane (APMDES) was used to modify SAPO-34 zeolite. The mixed matrix membranes were then examined by FTIR, TGA, SEM and gas diffusion analysis. CO2 and CH4 separation experiments showed that increasing the temperature reduces the CO2 / CH4 separation factor, while increasing the feed pressure and increasing the CO2 feed composition increases the separation factor. The results of experimental design showed that the feed pressure is the most important process parameter that affects the CO2 / CH4 separation factor. The MMMs synthesized in this study demonstrate competitive CO2 / CH4 separation performance compared to PES-based membranes in pure gas penetration tests.Keywords: mix matrix membrane, SAPO-34, Polyethersulfone, CO2 separation
- Effect of laminar pulsatile fluid flow on separation of volatile organic
compounds from aqueous solution by a hollow fiber membrane-based process
Abstract: In this study, a laminar pulsatile fluid flow was used for the separation of benzene, toluene, ethylbenzene and xylene isomers (BTEX) from aqueous solutions. The polyethersulfone hollow fiber membrane has been applied to this process. The effects of BTEX concentration, feed, and extraction flow rates were examined. It was found that the application of the pulsatile fluid flow with the frequency of 0.5 Hz significantly enhanced the separation process, and the removal efficiency has increased nearly twice. Moreover, the results showed that BTEX separation under pulsatile fluid flow was affected by the feed flow rate, extraction flow rate and the BTEX concentration as well.
- The effect of magnetic field on efficiency and fouling mechanisms during
membrane clarification of pomegranate juice
Abstract: Microfiltration can be used to clarify Pomegranate juice (PJ); however, it is fouled by charged particles. Magnetic field was coupled with microfiltration to reduce the membrane fouling. Results showed that magnetic field halved the total resistance; since, it increased the permeate flux. The most efficiency of application of the magnetic field in the membrane clarification was achieved at the high intensity of the magnetic field, low level of the feed flow rate and the direction of the magnetic field from the feed to the permeate side. Evaluation of the fouling mechanisms showed that with the increase in the intensity of the magnetic field, at the beginning of the process, the intermediate and standard blockings were dominant mechanisms, but over time, the formation of the cake became more important. Scanning electron microscope (SEM) showed that the layer of the cake deposited on the membrane surface in the absence of the magnetic field, inverse mode with the magnetic field, was very dense. On the other hand, the total monomeric anthocyanin content and the antioxidant activity of PJ increased; pH and total phenolic components were constant, and the total soluble solid content, the turbidity and the acidity were reduced.
- Evaluation of Textile Wastewater Treatment Using Combined Methods: Factor
Optimization via Split Plot RSM
Abstract: The increase in the consumption of textile products as well as the use of dye compounds has increased the pollution of the effluent in these industries. Discharge of this wastewater without properly treating can cause groundwater pollution, poisoning and serious health effects. Dyed pollutants contain benzene rings and are more resistant to conventional biological treatment such as activated sludge. In this study, two combined processes in series were applied for the treatment of towel dyeing wastewater. An experimental design was used to optimize the process. In a batch reactor, the anodic oxidation process (AO) and the electro-Fenton (EF) were compared using four anodes and cathodes. The performance of AO method in dye removal and COD reduction was better than EF method. A good agreement is attained between the predicted value using experimental design and actual results. The correlation coefficient of dye removal, energy consumption, and COD was achieved 0.966, 0.997 and 0.900, respectively. The results showed that under optimum operating conditions of AO process (voltage=6.5 V, t= 6 min and pH =9.5) decreased 97% of dye index and 61% of COD amount. This condition was obtained by consuming 6.7 kWh of energy per cubic meter of wastewater (0.07 $/m3). The output of the optimal AO entered the Reverse Osmosis (RO) system, in the last step. TDS of effluent was reduced 98% in the membrane and also the COD decreased from 980 to 13 ppm under 6 bar pressure.
- Effects of Applying Brand-New Designs on the Performance of PEM Fuel Cell
and Water Flooding Phenomena
Abstract: Numerous researchers use numerical simulations to precisely recognize the processes before mass-production to provide a basic model for optimizing the fuel cell. In this study, we presented brand-new designs for cylindrical PEMFCs in the Three-Dimensional form. We used the Finite Volume Method to simulate the fuel cell processes and established a genuine correspondence between our simulation results and valid outcomes. We introduced innovative designs to increase the performance of cylindrical polymer fuel cells. Then, we examined the effects of progressive developments in cross-section design, the fuel cell structure, the output current densities, and, eventually, the flooding phenomenon. The results revealed the optimum capacity of the cylindrical fuel cell compared with an elliptical cross-section. Due to more extensive transport zones and pressure drop effects, we need to find the optimum cell capacity to pass the reactive regions.
- Experimental investigation on super high viscosity oil- water two phase
flow in a horizontal pipe
Abstract: The flow patterns and pressure gradient of a two-phase mixture of water/super high viscous oil in a horizontal pipe were experimentally investigated. The mixture containing oil with a viscosity of 67 cP and density of 0.872 g/cm3, and pure water, flows through an acrylic pipe with a length of 6m and a diameter of 20 mm. Superficial velocities of water and oil were in the range between 0.18–1.2 m/s and 0.18–.95 m/s, respectively. Six flow patterns were identified. Stratified flow became visible at low oil (<0.42 m/s) and water (<0.26 m/s) velocities and bubbly flow pattern happened at low superficial oil velocities (Uso = 0.18–0.22 m/s). The dispersion of oil in water (DO/W) occurred at high superficial water velocity (Usw =0.79 – 1.2 m/s) at low or moderate superficial oil velocities (Uso = 0.18 –0.53 m/s). Dispersion of water in oil (DW/O) appeared from superficial oil velocity of higher than 0.69 m/s. Effect of oil viscosity on flow structure was assessed by comparing the present work with the available data and this revealed that the extent of dual continuous patterns reported by other systems containing low viscosity oil is 5% higher than the results of present study. The effect of oil viscosity on pressure gradient was also investigated. The pressure gradient values obtained in this study were 80% greater than other studies at similar superficial oil and water velocities. The experimental pressure gradient was also compared with the values predicted by the Al-Wahaibi correlation and two-fluid model. The Al-Wahaibi correlation agreed reasonably with the experimental results, with an average absolute error of less than 9%, while the error of the two-fluid model was 30%. Based on the results, a clear overview of the flow patterns and pressure drop with detailed information were presented.
- Drying characteristics, specific energy consumption, qualitative
properties, total phenol compounds and antioxidant activity during hybrid
hot air-microwave- rotary drum drying of green pea
Abstract: This study is aimed to investigate the effect of a hybrid hot air-microwave- rotary drum (HMRD) dryer on the thermal properties, quality and nutritional characteristics of green pea under different operational conditions. The experiments were conducted under different air temperatures (40, 55 and 70 °C), microwave power (90, 270, 450 and 630 W), and drum rotation speeds (5, 10 and 15 rpm). The thermal properties (e.g. drying time, effective moisture diffusion coefficient, activation energy, and specific energy consumption), quality features (color, shrinkage, and rehydration ratio) and nutritional properties (antioxidant activity and total phenol content) were determined. The results indicated that by increasing the microwave power, air temperature and drum rotation speed, the drying time will decline. The highest diffusion coefficient and energy consumption were determined as 5.04×10-11 m2/s and 109.91 MJ/kg, respectively. The lowest changes in the color, shrinkage, and rehydration were calculated as 41.34, 24.08% and 1.57. The highest total phenol (14.02 mg GAE/g d.w) and antioxidant (85.86%) were obtained. Thus the newly designed dryer can be employed for drying the granular products and lead to satisfactory results.
- Improving efficiency of a square cyclone separator using a dipleg –
a CFD-based analysis
Abstract: The present study is mainly focused on proposing an effective way to improve the efficiency of a square cyclone separator. For this purpose, a dipleg is attached under the square cyclone to investigate its effect on the performance of square cyclone. A three-dimensional Computational Fluid Dynamics (CFD) simulation is done by solving the Reynolds-Averaged Navier-Stokes equations with the Reynolds stress model (RSM) turbulence model and applying the Eulerian-Lagrangian two-phase method. The turbulent dispersion of particles is predicted by the application of the Discrete Random Walk (DRW) model. The numerical results demonstrate that using dipleg although produced an increase in pressure drop but it positively enhances the separation efficiency of the square cyclone. Using dipleg significantly increases the separation efficiency of square cyclone especially at higher inlet velocity. This can be more obvious when using dipleg which is minimized the 50% cut size of square cyclone about 26.3%.
- Effect of Flour Particle Size on Chemical and Rheological Properties of
Wheat Flour Dough
Abstract: The present study evaluates the effect of wheat flour particle sizes on the chemical and rheological properties of flatbread dough. Three wheat flour samples with particle sizes smaller than 125μm, 125-150μm and 150-180μm were examined for their chemical and rheological attributes. Flour with particle size of
- Survey of consumption pattern, exposure and risk assessment of aflatoxins
in different animal livers in Iran
Abstract: Aflatoxins are a group of toxic and carcinogenic metabolites produced by fungal species that are found in a variety of foods. Due to the high consumption of liver in Iran and especially in Kermanshah province, in this study consumption patterns of liver types (Sheep, Cow, and Chicken), the aflatoxin levels of liver types (B1 and G1) and hazard indexes including estimated daily intake (EDI) and margin of exposure (MOE) were investigated. Results showed that males had the highest liver consumption (52.3%) than females with a marked tendency towards consuming sheep liver (80.7%). The results of HPLC analysis indicated that aflatoxin G1 was detected in all types of the liver. Also, the mean concentration of aflatoxin in samples taken from autumn to winter in cows, sheep and poultry liver was 1.823, 0.7605 and 0.446 μg/kg. The results of EDI shows that cow liver was 2.33 ng/kgbw/day and above the threshold and the MOE level for all three liver types showed a high risk of cancer with the chicken liver incurring the highest risk with MOE = 78.2. Therefore, it is required to adopt an effective strategy regarding community education, attention to food safety and liver consumption in Kermanshah city.
- Synthesis of Magnetic Novel Hybrid Nanocomposite (Fe3O4@SiO2/Activated
carbon( by a Green method and Evaluation of Its Antibacterial Potential
Abstract: Inorganic antibacterial nanoagents have more advantages compared to popularly organic agents due to chemical stability, thermal resistance, immunity and long-term activity. In this study, a magnetically hybrid nanocomposite was prepared from the Nigella sativa oil waste as organic matrix in a green approach. The homogeneous distribution of core-shell Fe3O4@SiO2 nanoparticles on the activated carbon surface was carried out with a simple chemical method. Characterization of the synthesized nanocomposite was performed by different analysis techniques such as scanning electron microscopy–energy dispersive spectroscopy (EDX), scanning electron microscopy (SEM), x-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) surface area analysis. The antibacterial activities of the prepared nanoparticles against gram-positive and gram-negative bacteria were investigated and the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) values compared to imipenem as standard antibiotic. The effects of temperature, time and ratio of the activated carbon to Fe3O4@SiO2 on the MIC and MBC values of the prepared nanocomposites were investigated. The obtained results reveal the substantial role of all of these parameters in the gram-positive antibacterial properties, especially for S. agalactiae bacteria. The results show that the new proposed nanocomposite could be an alternative for an effective filter against gram-positive bacteria alongside having magnetic properties.
- Investigation of Doping Effect on Structural, Optical, Antibacterial and
Toxicity Properties of Iron Doped Copper Oxide Nanostructures Prepared By
Co-Precipitation Route
Abstract: In this work, pure copper oxide and Fe-doped copper oxide nanostructures [Cu1-x FexO where 0 ≤ x ≤ 0.08 in steps of 0.02] were synthesized using co-precipitation method. Iron nitrate nano-hydrate and copper nitrate trihydrate as precursors and NaOH was used as precipitating agent. The samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS) and UV-visible spectroscopy for their structural, morphological and optical properties, respectively. The effect of iron concentration on antibacterial activity and hemolysis were also investigated for Escherichia coli and Bacillus Subtilis. The XRD pattern showed the single-phase monoclinic structure of CuO nanoparticles. The average crystallite size of pure copper oxide was found to be 39 nm whereas average crystallite size of Fe-doped CuO was found to be in the range 39-44 nm. It was observed that average crystallite size was increased with increasing iron concentration in CuO. Scanning electron microscopy analysis showed the spherical like morphology and EDS confirmed the presence of iron and copper with proper composition. UV-vis spectroscopy results showed that band gap was decreased with increasing iron concentration. Samples prepared with higher concentration of iron exhibited high E. coli and B. subtilis antibacterial activity. Low hemolytic is safer to be used in various applications such as drug delivery.
- Preparation of magnetic cellulose nanocrystal -modified diatomite for
removal of methylene blue from aqueous solutions
Abstract: The magnetic cellulose nanocrystal-modified diatomite composite (MCNCD) was synthesized and its adsorption performance for removal of methylene blue dye (MB) from aqueous solutions was investigated. The as- prepared MCNCD samples were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, thermal gravimetric analyzer and vibration sample magnetometer, respectively. The adsorption parameters such as temperature, initial concentration of MB, adsorption time, and pH, were studied. The adsorption isotherms and kinetics were established. The results showed that adsorption isotherm and kinetics fitted well to the Langmuir model and pseudo-second-order model, respectively. Furthermore, the as-prepared MCNCD samples can be reused/ recycled after regeneration, with the adsorption capacity of 46.21 mg g-1 after six cycles.
- The Study of mechanical, thermal and antibacterial properties of
PLA/graphene oxide/TiO2 hybrid nanocomposites
Abstract: This study attempts to improve the anti-bacterial, thermal and mechanical properties of Poly-lactic acid (PLA)/Graphene oxide (GO) by incorporating the TiO2 nanoparticles. For this purpose, the TiO2 nanoparticles were introduced into PLA/GO films in content of 1, 3, and 5 wt.%. The film samples were prepared by solution casting method. The mechanical properties were evaluated by tensile test to report the tensile strength, elongation and elastic modulus. The thermal properties were investigated by Differential Scanning Calorimetry (DSC) and Thermal Gravimetric Analysis (TGA) tests, and the agar disk-diffusion method was carried-out to investigate anti-bacterial properties of the film samples. The Scanning Electron Microscopy (SEM) images showed the homogenous dispersion of the nanoparticles in the PLA matrix. TGA results showed that incorporating GO and TiO2 nanoparticles considerably improve the thermal stability of PLA matrix.
- Optimization of adsorption parameters using central composite design for
the removal of organosulfur in diesel fuel by bentonite-supported
nanoparticle NiO-WO3
Abstract: Desulfurization using porous materials is based on the capability of a solid sorbent to selectively adsorb organic sulfur-containing compounds. In the present study, different sorbents were prepared by varying the NiO-WO3 loadings onto bentonite for the removal of sulfur from commercial diesel fuel containing approximately 100 ppm total sulfur (S). X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) were used for the characterization of the modified bentonite. A Plackett–Burman design (PBD) was chosen as a screening method to estimate the relative influence of the factors that could have an influence on the analytical response. The significant variables included: sorbent amount, feed volume, extraction solvent kind and its volume were optimized using central composite design (CCD). 93.5% removal of sulfur was observed with NiO-WO3/bentonite.
- Removal of Acid Red 33 from aqueous solution using nanoscale zero-valent
iron supported on activated carbon: Kinetic, isotherm, thermodynamic
studies
Abstract: In this study, zero-valent iron nanoparticles immobilized on activated carbon (nZVI-AC) was synthesized to rapid remove Acid Red 33 (AR 33) as an azo dye from aqueous medium. This novel nanocomposite were characterized by scanning electron microscopy (SEM), energy dispersive X-Ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The effect of experimental variables, including adsorbent dosage, pH, initial concentration of AR 33, and the temperature was studied to select the optimum conditions for the maximum removal efficiency. The optimal conditions were achieved at an adsorbent dosage of 0.2 g/ l, pH=3, initial dye concentration of 10 mg/ l, and a temperature of 313 K. Isotherms and kinetics studies indicated that Langmuir isotherm with regression determination (R2) of 0.9914 and pseudo-first-order model with R2=0.9922 fitted well to the experimental data. The calculated thermodynamic parameters such as ΔGº, ΔHº, and ΔSº revealed that adsorption process was spontaneous and endothermic. The reusability of the nZVI-AC was investigated and it found that this adsorbent had a potential ability to remove AR 33 dye.
- The catalysis of ferric chloride in the preparation of graphene oxide film
Abstract: Accurate analysis of the catalysis of ferric chloride in the preparation of graphene oxide film can improve the performance of the finished product. The thermal conductivity of graphene film prepared by the original method is low, so a new catalytic analysis method is proposed. Firstly, the flake double-layer graphite oxide is prepared by the improved Hummers method. Under the catalysis of FeC13, different reaction temperature and reaction time are set to get the finished products of graphene oxide under different conditions. The structure characteristics of the finished products are analyzed, and the structure of that the graphene oxide films prepared at 90 ℃ and 0.5h is determined is the best. So far, the catalysis of ferric chloride in the preparation of graphene oxide film has been analyzed. The results show that the thermal conductivity of graphene oxide film prepared by catalysis is 900W / (m · k), which is higher than that of traditional products.
- Photocatalytic oxidation of methanol selectivity in the preparation of the
application of methylformate
Abstract: In order to improve the application performance of methanol selective photochemical oxidation in the preparation of methyl formate, the catalytic performance of different oxides was analyzed. A series of TiO2 catalysts supported by gold, silver and copper were synthesized by the method of metal sol deposition. The catalytic properties of different oxides were analyzed. The most appropriate amount of methanol was selected to explore its application in the preparation of metal formate. The effects of temperature, load, space velocity and other factors on the catalytic properties were explored through experiments. By comparing the catalytic performance of different oxides, it is found that when the oxides are CH3OH, the prepared CH3OH / MoO3-SnO2 has better catalytic effect. Therefore, the catalyst with good dispersion and suitable acid-base position is more favorable for the formation of methyl formate and the conversion of methanol.
- Efficient and scalable methods for synthesis of midazolam drug with an
annulation process
Abstract: The reported methods for the synthesis of midazolam include a number of disadvantages, such as high production cost and low yields. The purpose of this investigation was to develop a more economical and technically more feasible route to synthesis of midazolam. In this research, two easy and scalable synthetic methods for the production of midazolam drug are presented. One-pot condensation of imidoyl chloride or 1,4-benzodiazepinic N-nitrosoamidines with carbanion of two isocyanide reagents is described and two important and key tricyclic ring intermediates synthesized. These imidazo-type structures can be derivatives by the alkylation of the imidazole ring with tert-butyl magnesium chloride at 0 °C in excellent yield, which have not been described for these intermediates in the literatures.
- Dinuclear copper(II) complex of containing
N,N-diisopropyl,N'-3-propylamide-ethylenediamine and dihydroxo
bridge; Solvatochromic and Thermochromic
Abstract: The synthesis and characterization of dinuclear [LCu(m-OH)2CuL](ClO4)2, complex with a tridentate N,N-diisopropyl,N'-3-propylamide-ethylenediamine hemilabile ligand (abbreviated L) is reported. The dinuclear complex was characterized by elemental analyses, molar conductance, thermal analysis and spectral studies. In the complex two copper centers are 5-coordinated and bridged through two hydroxo groups. Thermo- and solvatochromic behaviors of the complex were investigated by visible spectroscopy. Its reversible thermochromism (blue ↔ green) is due to breakage and re-coordination of Cu-O(amide) moiety in acetonitrile solution. The solvent-dependent absorption maxima, max, was studied by a stepwise multiple linear regression (SMLR) analysis to determine the best model describing the resulting positive solvatochromism. The statistical results demonstrated that among different solvent parameters, donor number (DN) is a dominant parameter responsible for the redshift in the d-d absorption band of the complexes with increasing its values.
- Analysis of Thermal Decomposition Kinetics and Calculation of Activation
Energy for Degradation of Polyaniline-Graphene Oxide
Composites-Synergistic Reinforcement on Thermal Stability
Abstract: Thermogravimetric Analysis (TGA) is one of the most commonly used techniques to study the thermal stability of a materials. Thermograms not only give an instant view of the thermal stability but it can also give insights into the degradation kinetics of the material. This study reports on the degradation kinetics of composite materials based on polyaniline and graphene oxide (PANI-GO) synthesized with varying amount of GO. Horwitz & Metzger, Coats & Redfern and Chan et al., methods were employed for calculation of activation energy for degradation, using TGA data. It was observed that their thermal stability and activation energy of degradation are affected by changing the amount of GO during polymerization, indicating PANI and GO synergistically enhance the thermal stability of PANI-GO composites. The highest activation energy value of 29.87 kJ/mol was shown by composite that contain 6 percent GO. Ultraviolet Visible (UV-Vis) spectroscopy, X-Ray Diffraction (XRD) Analysis also support variations in different properties of the composites as a result of changing GO concentration
- Applications of multi-layer perceptron artificial neural networks for
polymerization of expandable polystyrene by multi-stage dosing Initiator
Abstract: In this research, Expandable Polystyrene (EPS) polymerization with conventional and Multi-stage Initiator Dosing (MID) methods is simulated by Multi-layer Perceptron (MLP) Artificial Neural Networks (ANN). In order to optimize MID method, an efficient algorithm was employed for optimal training of neural network. An algorithm was used to train the MLP networks more rapidly and efficiently than the conventional procedures. The main objective of MID method implementation is to reduce the time of the polymerization and because of that, by having different tests (first stage polymerization at 4, 3.5, 3, 2.4 hours and different amounts of used initiator at common state 100, 80, 75, 70 percent and different number of dosings 12, 10, 8, 6) it was found that in optimal state, the first stage polymerization time can be 3 hours and amount of the used initiator can be reduced to 70% in compare to common state and number of dosings can be 6 times.The results of the simulation showed that the time of the first step of the polymerization has been reduced, and the amount of the used initiator has been optimized and the count of the dosing times reduced to half, and therefore the time of the EPS polymerization is reduced to 60% of the conventional method.
- Preparation and characterization of a novel polysulfone (PS) mixed matrix
membrane modified with a SAPO-34 nanofiller for CO2/CH4 gaseous mixture
separation
Abstract: Blended matrix polymer membranes have attracted attention today due to their high efficiency in gas separation. In this study, PS / SAPO 34 polymer membranes were synthesized and evaluated by phase separation method. ُynthesized PS/SAPO-34 mixed matrix membranes (MMMs) were characterized via FESEM, TGA and DSC analyses. Various parameters such as air gap distance, dope extrusion rate, and jet strech were examined. After that, the process of separation of CO2 and CH4 gases was investigated. The results showed that the addition of SAPO nanoparticles improved membrane performance. The highest selectivity was obtained at temperature 28 and pressure 0.5 bar. Permeation results manifested that the PS/SAPO-34 fabricated at optimum conditions has incredible worth from the prospective of industrial separations of CO2 from flue and natural gas.
- Liquid-liquid extraction of Toluene from Heptane using [EMIM][NTF2] ionic
liquid: Experimental and extensive thermodynamics study
Abstract: The performance of the ionic liquid (1-ethyl-3methylimidazolium bis(trifluoromethylsulfonyl)imide, [EMIM][NTF2]) as a green, non-aqueous and hydrophobic solvent and sulfolane as a conventional solvent for liquid-liquid extraction of toluene from its mixture with heptane was investigated. The LLE phase behavior was predicted with the help of the UNIFAC as a predictive thermodynamic model. The interfacial tension of the studied systems was measured to investigate the effect of the dissolved toluene concentration on interfacial tension. It was revealed that the average selectivity of the systems with IL (316.752) is much higher than the systems containing sulfolane (18.661) under similar experimental conditions. For low mass fractions of toluene less than 0.4, the performance of the IL is better, whereas, for high toluene mass fraction more than 0.4, sulfolane exhibits superior performance.
- Effects of Halide Anions on Water Desalination based on Crystallization
Methods: Freezing and Tetrahydrofuran Hydrate formation
Abstract: In this study, the water desalination was performed using the freezing method and Tetrahydrofuran hydrate formation in a stationary reactor. The experimental setup includes two coaxial cylinders, which ice crystals deposit outside the cool inner cylinder; thus the salt concentration increases in the residual brine. In order to evaluate the performance of these methods, the removal percentage of salt was measured by the electrical conductivity instrument. The results show that the removal efficiency decreases with an increasing salt concentration in the freezing method while the different trend is observed in the hydrate formation method. As an important result, the salt removal efficiency of the hydrate formation method was higher than the freezing process. Also, to investigate the effect of the anionic size on the salt removal efficiency, the experiments were performed with NaCl, NaBr, NaF, and NaI, which have the same cations. The results show that the performance of desalination improves by increasing anionic radius. So the dissolved mineral components are removed in the following order. The removal of salts with a higher size is further by the hydrate-based and freezing desalination.
- MHD Convection of an Al2O3–Cu/Water Hybrid Nanofluid in an Inclined
Porous Cavity with Internal Heat Generation/Absorption
Abstract: In Present communication, the transference of the hybrid nanofluids due to the natural propulsive like shrinkage and relaxation of the flexible walls and the motion has serious applications in several embryonic technologies. Stimulated by the multi-disciplinary development and study in this trend, a mathematical model is suggested to explore the numerical simulation of the hybrid nanofluid flow inside a slant porous cavity to determine the impact of volume fraction, Rayleigh number, heat generation and heat source length and location on magneto-free convective with entropy analysis. The governing nonlinear problem is converted into non-dimensional partial equations via suitably adjusted transformations. Successive Under-Relaxation (SUR) technique has been incorporated to find the solutions of the non-linear problem. Variation in entropy generation and heat transfer characteristic and thermal performance criteria has been noted for various fluid parameters. The results are plotted graphically. The outcomes indicate that the thermal performance reduces more in the case of high volume fraction in comparison with low concentration. The addition of nanoparticles for several Rayleigh numbers causes the thermal performance to be declined.
- Investigation of effects of heater tube angle on the pool boiling heat
transfer coefficient
Abstract: In this experimental study, the effects of slope changes on the heat transfer coefficient in the pool boiling in deionized water have been investigated. The experiments were carried out in the average surface roughness of 0.21 µm on a copper cylinder by changing in the surface slope including 0°, 5°, 10°, 15°, 20°, 25°, and 30°. The range of heat flux was from 21 to 77 kW.m-2 in the atmospheric conditions. The results indicated that by increasing the heater slope, the departure frequency and bubble departure diameter on the heater surface were increased which lead to an increase in the mixing, turbulence, and the heat transfer coefficient. Finally, the slope of 15° has reached the highest heat transfer coefficient with an increase of 20.09% compared to other slopes. Besides the optimized model was mostly overlapped with the experimental results in which Stephan Abdelsalam model with an average error of 13.9% and McNelly model by an average error of 24% had the minimum and maximum amount of error among the other models, respectively.
- Inverse Estimation of Time-Dependent Heat Flux in Stagnation Region of
Annular Jet on a Cylinder Using Levenberg–Marquardt Method
Abstract: All solving methods available in literature are formulated for direct solution of stagnation point flow and its heat transfer impinging on the surfaces with known boundary conditions. In this paper for the first time, a numerical code based on Levenberg–Marquardt method is presented for solving the inverse heat transfer problem of an annular jet on a cylinder and estimating the time-dependent heat flux using temperature distribution at a specific point. For this purpose, the numerical solution of the dimensionless temperature and the convective heat transfer in a radial incompressible flow on a cylinder rod is carried out as a direct problem. Using similarity variable and appropriate transformations, momentum and energy equations are converted into Semi-similar equations. The heat flux is then estimated by applying the Levenberg–Marquardt approach. This technique is an iterative approach based on minimizing the least-square summation of the error values, the error being the difference between the estimated and measured temperatures. Results of the inverse analysis indicate that the Levenberg–Marquardt algorithm is an efficient and acceptably stable technique for estimating heat flux. This method also exhibits considerable stability for noisy input data. The maximum value of the sensitivity coefficient is related to the estimation of exponential heat flux and its value is 0.1619 also the minimum value of the sensitivity coefficient is 5.6210-6 which is related to the triangular heat flux. The results show that the parameter estimation error in calculating the triangular and trapezoidal heat flux is greater than the exponential and sinus–cosines heat flux because the maximum value of RMS error is obtained for these two cases, which are 0.481 and 0.489, respectively the reason for the increase in the errors in estimating these functions is the existence of points where the first derivative of the function does not exist.
- Exergoenvironmental and Exergoeconomic Modelling and Assessment in the
Complex Energy Systems
Abstract: Traditionally energy systems were analyzed technically, but current environmental issues and considerations have put new constraints on the planning and managing energy systems. Such an exergoeconomic and exergoenvironmental analysis were born. This analysis is aimed to describe the necessity and application of a new concept in environmental liability accounting based on physical quantities to overcome the weaknesses of the developed allocation methods and the internalization of external environmental damages. The proposed method is modified in environmental analysis to consider the effect of non-energy flows on a macro surface energy system. As a case study, this method is tuned for a complex energy system. It has been shown that environmental responsibilities, calculated based on exergy destruction in the order, represent the role of the units in the overall emission and contribution to integrated environmental management. The comparison shows that responsibilities are higher than emission reductions for service units, and the difference between duties and permits may not reflect the costs of internal damage. The exergoeconomic and exergoenvironmental analysis is used to model the concept of the economic-environmental footprint of the system in a quantitative process, and this is the most crucial advantage of this method. In this paper, this method is implemented on a solar thermal power plant combined with the steam cycle system as a case study.
- Modeling of Direct Contact Condensation in the Water-Saturated Zone of the
Soil Exposed to Steam Injection
Abstract: In this paper, the phenomenon of direct-contact condensation in porous media has been investigated based on the computational fluid dynamic technique, CFD, for hydraulic and thermal phenomena assessment. This phenomenon occurs in soil remediation by steam injection. The main contribution of this research is developing a new combined model for considering steam condensation in the saturated porous media systems using the direct contact condensation model, DCC, and Navier-Stockes equations rather than solely using Darcy’s law-based model. For the first time, a two-resistance DCC model for porous media application has been included, predicting propagation of steam front and condensation. The corresponding source and sink terms due to the calculated condensation rate are added to each phase continuity equations and enthalpy equation of the liquid phase by user-defined functions, UDFs. Pressure drop due to flowing fluids in the porous structure was considered by lumped approach model using viscous and inertial loss terms added to momentum equations of the model. Heat loss from the sandbox is considering as a sink term based on the calculated overall heat transfer coefficient and local temperature differences. The model results meet acceptable predictions for steam saturation content and temperature distributions over time and the predictions are qualitatively similar to the experimental and simulation results of the previous literature. The quantitative values of the sandbox covered thermal areas, extracted from propagated saturated temperature fronts over processing time, are compared for both DCC simulation results and available experimental measurements. After elapsing 12 and 18 minutes from the beginning of the process, the simulation values of covered thermal areas are 0.049 m2 and 0.082 m2. The corresponding experimental values are 0.059 m2 and 0.098 m2, respectively. Evaluated absolute values of the relative change percent of covered thermal areas are 16.3% and 16.9% over processing times of 12 and 18 minutes.
- Evaluation of Thin-layer Models for Kinetic Analysis in Unbleached Kraft
Pulpboard Drying
Abstract: The drying characteristics of unbleached Kraft pulpboard has been studied in a convective drying equipment under different hot air temperature and velocity. In this work, the drying experiments were conducted in the range of 80-100℃ and 1.87-2.48m/s, respectively. The drying characteristics results indicated that high air temperature and velocity is beneficial to increase drying rate and decrease drying time. Ten thin-layer drying models were evaluated to describe the drying kinetic of unbleached Kraft pulpboard for its suitability. Based on the statistical analysis, the Yun model could predict the pulpboard drying kinetic better than others in terms of fitting performance. Through calculation and fitting, the effective moisture diffusivity varied from 2.07710-10 to 3.63110-10m2/s over the investigated temperature range, and the average activation energy for moisture diffusion was 22.818kJ/mol.
- Effect of partial replacement of sodium chloride by potassium chloride on
rheological, sensory, qualitative and microbial properties of baguettes
Abstract: ABSTRACT: The aim of the current study was to investigate effects of partial replacement of sodium chloride by potassium chloride on rheological, sensory, qualitative and microbial characteristics of baguettes. Replacement of sodium chloride by potassium chloride in null flour at 0% potassium chloride (control group, 100% sodium chloride), Treatment 1 (75% sodium chloride and 25% potassium chloride), Treatment 2 (50% sodium chloride and 50% potassium chloride), Treatment 3 (75% sodium chloride and 25% potassium chloride) and Treatment 4 (100% potassium chloride) was studied in baguettes. Results of the microbial count of flour showed that Treatment 2 included the highest yeast number of Saccharomyces cerevisiae. Investigation of rheological characteristics of dough using farinograph and extensograph devices showed significant differences in experimental treatments (p ≤ 0.05) that Treatment 2 showed better conditions than other experimental treatments. Assessment of the sensory characteristics of baguette demonstrated efficacy of Treatment 2 in treatments and significant differences were observed in porosity, texture and taste of breads (p ≤ 0.05). Therefore, it seems possible to produce breads with less levels of sodium chloride and partly substitute them with potassium chloride with no significant effects on the quality of breads. In conclusion, replacement level of 50% potassium chloride by 50% sodium chloride is suggested to produce baguettes with good quality.
- Analysis of Flocculation Activity of Microparticle Solution of Salty
Protein from Whey of Oviparous Animals
Abstract: Because the traditional method does not consider the release rate of salty whey protein particles after adding flocculants, the error in the peak test of the flocculation activity of the ovarian animal whey protein particle solution is relatively high, which leads to the unreliable analysis of the flocculation activity. Therefore, a method is proposed. A new method for analyzing the flocculation activity of egg-shaped animal whey protein particle solution. According to the basic characteristics of whey protein, the basic structure of the flocculation model was reset to improve the purification effect of the whey protein particle solution in eggs. By calculating the loading rate and analyzing the effect of the flocculating carrier on the stability and release of individual particles, the release rate of salty whey protein particles after adding flocculants can be obtained. Combining the activity distribution with the propagation algebra, the flocculation activity analysis result is obtained. Experimental results show that this method can effectively reduce the error rate of the peak activity test, improve the reliability of the analysis of the flocculation activity of the ovarian animal whey protein particle solution, and has better stability and analysis effect than the traditional method.
- Investigating the influence of operating conditions on the combined steam
and carbon dioxide reforming of methane performance in the presence of
Ni/ZrO2 catalyst
Abstract: In the present study, Ni/ZrO2 catalyst was synthesized via co-precipitation approach and its catalytic activity was evaluated in combined steam and carbon dioxide reforming of methane (CSCRM) reaction at a temperature range of 773 K–1273 K, CO2:H2O ratio of 0.5-3 and (CO2 + H2O)/CH4 ratio of 0.5-3. The results demonstrated that the higher (CO2+H2O)/CH4 ratio and temperature were required for CH4 conversion about 100%. The effect of CO2/H2O ratio was little on the CO and H2 yield. A (CO2+H2O)/CH4 ratio of 1.5 associated with CO2/H2O ratio of 0.5 at the minimum temperature of 1073 K were the required reaction conditions for the synthesis gas (syngas) formation with H2/CO ratio about 2. The temperature, type and amount of the oxidizing agent greatly affected on the amount of coke deposition. The least temperature of 1073 K and (CO2+H2O)/CH4 ratio higher than 1.5 irrespective of CO2:H2O ratio was obtained as a proper operation conditions to avoid coke formation. Moreover, CO2 revealed a higher portion than H2O in coke formation in CSCRM reaction.
- Hydrophobic Silica nanoparticle & Anionic/ Cationic surfactants interplays
tailored interfacial properties for the wettability alteration and EOR
applications
Abstract: In this study, the effect of anionic and cationic surfactant solutions alone and in combination with silica AEROSIL® R 816 nanomaterial on the wettability alteration of carbonate rock reservoir has been investigated. The nanofluid properties including stability, surfactant critical micelle concentration (CMC), Interfacial tension (IFT), and surfactant adsorption were studied that in each case, the synergistic effect of nanoparticles as adjacent particles along with surfactant molecules in the solution with respect to electrostatic and capillary forces has been discussed. The results show that nanoparticles generally reduce ST, CMC, surfactant adsorption on the rock, and surfactant molecules significantly increase the stability of nanoparticles. Also, contact angle test results indicated an increase in the effect of the wettability alteration of stones in the surfactant solution by the nanoparticles from the lipophilic to the hydrophilic, and the nanopowder solution itself had the most ability to change the wettability. Finally, the results from the observations as mentioned above were confirmed by performing imbibition test based on drop experiments.
- Upgrading Atmospheric Residue by Simultaneous Employment of Ionic Liquid,
Ultrasonic and Thermal Cracking
Abstract: In this study the effect of simultaneous employment of ultrasonic wave radiation, chemical substance of ionic liquid and operating conditions of thermal cracking is investigated experimentally on upgrading the atmospheric residue (AR) of a crude oil atmospheric distillation tower. Five main factors of this process that are investigated are ionic liquid concentration, ultrasonic wave power, ultrasonic radiation time, temperature and pressure. According to Box-Behnken Design, 46 experiments are conducted. Then, the proper experimental condition of this process is determined and hence, based on Multilevel Categoric Design the efficiency of seven different kinds of ionic liquids is compared. According to this design, 14 experiments are conducted. The results of 46 experiments conclude that this process is able to upgrade AR and even the simultaneous employment of ionic liquid, ultrasonic and thermal cracking cause a synergistic effect on AR upgrading. Also, the results of 14 experiments indicate that 1-Propyl boronic acid-3-decylimidazolium bromide is a desirable ionic liquid for this process.
- Evaluation, Preparation and Characterization of Chitosan/ZnO Nanocomposite
and Antibacterial activity against pathogenic microbial strains
Abstract: : Objective (s): Background: Nanotechnology is used as a tool to develop advanced therapies and control the fight against infections. The aim of this study was to evaluate of the physicochemical properties such as morphological analysis of the chitosan nanocomposite on oxide composite through a simple method and to investigate the anti-bacteria properties of them.Materials and Methods: The study method in in this study was experimental and the chitosan-zinc oxide nanocomposite was chemically precipitated after preparation of the Chitosan/ZnO nanocomposite physicochemical properties and antibacterial activity against pathogenic microbial strains was investigated. The nanocomposite was evaluated using SEM, FTIR techniques, XRD X-ray diffraction and DLS particle size distribution. The antimicrobial effect of this nanocomposite was evaluated on the bacteria Staphylococcus aureus and Micrococcus luteus. In this study, the antimicrobial effect of Chitosan/ZnO nanocomposite ZnO nanoparticles loaded in chitosan was investigated by MIC method on microorganisms (Candida albicans, Microscotus luteus and Staphylococcus aureus).Results: The results showed that the concentration of zinc oxide nanoparticles affected the antimicrobial activity of chitosan nanocomposite. In this study, the antimicrobial behaviour of the Chitosan/ZnO nanocomposite zinc oxide was determined against pathogenic microbial strains of bacteria including Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, Micrococcus luteus, Bacillus subtilis, Staphylococcus aureus, and Klebsiella pneumoniaagainst E .Coli was investigated and the results show that zinc oxide has an antimicrobial effect against Escherichia coli and also the use of two types of dispersants (peg / pvp) on antimicrobial activity of zinc with MIC .(Minimum inhibitory concentration) approach. The ZnO nanoparticlesoxide has no effect and onlyin the Chitosan/ZnO nanocomposite increases the stability of the suspensions. Conclusion: Based on the results, the synthesized compounds have an antimicrobial effect and the antimicrobial effect has increased with increasing polymer (chitosan) concentration. The antimicrobial effect has been seen on gram-positive and gram-negative bacteria.
- Characterization of Phosphorus and GGBF slags as low-cost adsorbents for
Cu(II) removal
Abstract: Cu(II) is one of the pollutants that is exist in the produced wastewater by many industries. According to the World Health Organization (WHO), its concentration should be less than 2 mg/L. In this study, Phosphorus slag (PS) and ground granulated blast-furnace slag (GGBFS) as industrial wastes with the properties of abundant and low cost are used to remove Cu(II). The effects of shaker rotation rate, initial concentration of Cu(II), and amount of adsorbent on the adsorption process are investigated. The adsorption capacity was maximized at a shaking rate of 150 rpm, initial concentration of 50 mg/L, 0.2 g GGBFS per 0.03 liter, and 0.5 g PS per 0.03 liter. At various temperatures, the values of thermodynamic parameters were calculated by measuring the equilibrium data. The results showed that the adsorption process was exothermic using both GGBFS and PS adsorbents. The experimental data of Cu(II) adsorption by GGBFS and PS was fitted well by Langmuir and Freundlich isotherm models, respectively. The maximum adsorption capacity were obtained 156.30 and 151.52 mg/g for GGBFS and PS, respectively. Also, the kinetic modeling indicated that the adsorption process is achieved to the equilibrium state using both adsorbents at less than 5 min.
- Synthesis of Disaccharide based Xanthates for the Removal of Some Heavy
Metals from Aqueous Solutions
Abstract: Two samples of lactose xanthates (LX1 and LX2) have been synthesized by the reaction of lactose (La), and carbon disulphides (CS2) in basic medium using NaOH/KOH. The synthesized products were extracted with diethyl ether and dried in air resulting in the formation of yellow coloured liquid products. The formation of synthesized xanthates has been confirmed by FT-IR (IR) spectroscopy and elemental analysis. The synthesized xanthates were utilised for the removal of heavy metal (CuII and NiII) ions and turbidity from wastewater. It was found that, LX1, LX2 and pure lactose (La) removes 94.9%, 95.4%, 93.8%, &95.4%, 73.3%, 70.98% of CuII and NiII respectively. These results show improved metals and turbidity removal with LX1, LX2 in comparison to many other coagulants reported in literature.
- Evaluation of living Azolla filiculoides performance for the removal of
total nitrogen, phosphorus, sodium, potassium, COD, BOD, and TDS from
dairy waste: Full factorial design
Abstract: In this study, the potential of living Azolla filiculoides was investigated to treat dairy wastewater. The full factorial design was performed to evaluate the effect of contact time, pH, and temperature on the removal of total nitrogen, phosphorus, sodium, potassium, chemical oxygen demand (COD), biological oxygen demand (BOD), and total dissolved solids (TDS). At the contact time of 6 h, the removal efficiencies of 74.67% and 28.78% have been observed for sodium and TDS, respectively. Also, the removal efficiency of 59.20% has been obtained for phosphorus at the contact time of 18 h. The results indicated that Azolla filiculoides can be used successfully as an effective adsorbent for sodium and phosphorus removal.
- Reductive remediation of Cr(VI)-contaminated soils in the presence of
zero-valent metals and bimetals
Abstract: The time-dependent efficiency of zero-valent metals (ZVMs) including Al0 and Zn0 and their bimetals (Fe/Al and Fe/Zn, 0.1 g shell metal g-1 core metal) to reduce Cr(VI) in three contaminated soils (calcareous, non-calcareous near neutral and slightly acidic) was studied. The Cr(VI)-contaminated soils (100 and 500 mg kg-1) were amended with the reductants (0, 5 and 10 g kg-1) and the concentration of exchangeable Cr(VI) was determined after 0.5, 4, 24, 48 and 168 hours. It was found that the average reducing capacity of the bimetallic particles (11.4 mg Cr g-1) was much higher than the ZVMs (3.3 mg Cr g-1). The ZVMs showed a rapid passivation within only a few minutes, while the bimetallic particles preserved their reactivity even up to one hour. In addition, the efficiency of ZVMs in the slightly acid soil was much higher than two other soils. There was a good performance of Fe/Al in the calcareous soil with a higher hazard potential than two other soils. The Cr(VI) reduction capacity of the bimetallic particles in non-calcareous near neutral soil was two times more than in calcareous soil. The pseudo-first order Cr(VI) reduction rate constants for the bimetals (0.248 h-1) was on average higher than those of the ZVMs (0.074 h-1).
- Decolourization of Disperse Blue 3 Dye by Electro coagulation process
using Al and Fe electrodes –Application of the Artificial Neural
Network Model
Abstract: Contamination in wastewater is a major issue in the present world, the Disperse blue 3 dye (DB3) removal was studied by an electro coagulation process using Al and Fe electrodes. The experiments were performed with synthetic solutions in batch mode. The effect of the operating parameters like the electrolysis time, current density, initial pH, conductivity, inter-electrode distance and initial dye concentration, has been investigated. The results show high discoloration efficiency, reaching 98 and 96% with Al and Fe electrodes respectively. At the optimum condition of the EC process were electrolysis times of 70 and 30 min, current densities of 139 and 93 mA/cm², initial pH 5, conductivity of 5.67 mS/cm and inter-electrode distance of 1.5 cm. The Artificial Neural Network (ANN) technique was used to model the experimental data of the current density. The feed-forward neural network model was optimized by using the Levenberg-Marquardt algorithms. A comparison between the predicted and experimental data gave high correlation coefficients (0.99977 and 1) with the minimum MSE value (1.55.10-7 and 1.31.10-5) respectively for Al and Fe electrodes.
- ZnO/bone-char hybrid composite: Catalyst preparation, characterization and
its application
Abstract: This study was aimed at the development of the ZnO/bone-char (ZnO/BC) hybrid composite and it was characterized for its suitability for the treatment of dye-containing wastewater. The Zn/BC composites were prepared using four different methods such as sol-gel, precipitation, hydrothermal and wet-impregnation methods. Various analysing techniques such as X-ray diffraction (XRD), Fourier Transform Infra-red (FT-IR), Brunauer-Emmett-Teller (BET) surface area and Scanning Electron Microscopy (SEM) were performed to characterize the prepared photocatalysts. The photocatalytic activity of the ZnO/BC composite prepared from the sol-gel method was evaluated by the decolorization of brilliant green dye in aqueous solution. The results of SEM analysis confirm the agglomeration of nano-ZnO particles and particles are evenly distributed on the surface of the bone char. Moreover, the influence of different experimental parameters like solution pH, H2O2 concentration and photocatalyst dosage was studied to optimize the process efficiency. This study also shows that the chicken bone waste can be used as a photocatalyst carrier for the synthesis of photocatalytic composites. It does not only provide a better way to treat dye-containing wastewater, but also offers an ideal solution to use chicken bone waste. From the kinetic analysis, it has been observed that the photocatalytic decolorization of BG dye with ZnO/BC photocatalyst follows pseudo-first-order kinetics.
- Biochar produced from co-pyrolysis of olive pomace & crude oil as an
adsorbent for Cr (VI) removal from aqueous solutions
Abstract: This study investigated aqueous solution treatment to remove Cr (VI) using biochar-based adsorbent. Olive pomace and crude oil were used to synthesize the biochar adsorbent via co-pyrolysis for the first time. The biochar properties were examined with Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyses before and after adsorption. The adsorption experiments were carried out in batch process under different experimental conditions. The optimum adsorption efficiency was experimentally found to be at pH of 1.5, contact time of 15 min, Cr (VI) initial concentration of 20 mg L-1, adsorbent dose of 0.4 g, and 303 K. Langmuir and Freundlich isotherms were used to evaluate the adsorption performance of biochar, and the Langmuir isotherm model was well fitted to experimental data with a maximum adsorption capacity of 9 mg g-1. Kinetic experimental data was best described using a pseudo second order kinetic model. The thermodynamic parameters of adsorption process were examined in detail, and the process was exothermic and spontaneous in nature. It is concluded that the biochar can be successfully used as an adsorbent for the treatment of Cr (VI) contaminated water. Additionally, evaluation of olive pomace provided not only a decrease in waste accumulation in olive production industry, but also synthesis of inexpensive and environmental friendly adsorbent.
- Engineered Algal Biochar for the Sequestration of Cu2+ from Aqueous
Solution
Abstract: The provision of safe drinking water in low-income countries is problematic due to high levels of pollution and high cost of water treatment. While existing water treatment methods are efficient in removing most contaminants, they are expensive. Adsorption methods may be a cheaper and efficient alternative, given that feedstock for the fabrication of adsorbents are readily available, and they are easy to produce. The objective of this study was to synthesize and evaluate the performance of algae-derived adsorbents in removing Cu2+ form wastewater using batch experiments and fixed-bed columns. Algal biomass was pyrolyzed under limited oxygen to produce biochar (BC), which was separately activated using: (1) ferric chloride to form a Fe2O3-BC composite, and (2) KMnO4 and H2SO4 through a modified Hummer’s method to form HBC. Batch experimental data fitted well in both pseudo-first order (r2=0.965) and pseudo-second order (r2=0.946) kinetic models, and there was no significant difference (p=0.349). The Yoon-Nelson (r2=0.879) and Thomas (r2=0.891) models adequately described the experimental data, while the Adams-Bohart model had low fit (r2=0.673) in column studies. The results showed that the biosorbents were effective in removing Cu2+ from wastewater, with HBC having a higher affinity than Fe2O3-BC and BC. FTIR measurements after adsorption suggest that carbonyl groups played a key role in binding Cu2+ ions. Overall, valorizing algal biomass potentially helps towards solving the problem of algal blooms, while providing material for treating water. Further research should investigate the economic feasibility and up-scaling of the technology to field-scale.
- Derivatization of curcumin and the effect of resultant derivatives on
BRC-9 breast cancer cells
Abstract: The Medicinal herbs have been taken into consideration for cancer treatment because of the high prevalence of cancer and severe consequences of chemotherapy. Turmeric, the common name of the Curcuma longa plant, is one of these herbs as Indian spices being applicable for food spices as well as treatment of various diseases. Medicinal and biological effects of turmeric are actually associated with the main component of its rhizome, i.e. curcumin. The Curcumin has antioxidant, antibacterial, anticancer, antifungal, and antiviral properties. In this research, curcumin derivatives were synthesized via condensation reaction of some aromatic amines (aniline, 2-nitroaniline, 4-ethyl aniline) with curcumin. The effects of molar ratio of amine: curcumin on the type of products were also examined. The structure of products were characterized by FT-IR, 1HNMR, and 13CNMR spectroscopy. The anticancer activities of compounds were investigated by the MTT assay (4,5-dimethylthiazol-2-yl) - 2,5 - diphenyltetrazoliu bromide test). It was evaluated with different dosages of curcumin derivatives at different times against BRC-9 breast cancer cells which exhibited the most potent anticancer activity.
- A simple method for the preparation of 2,4,6-trichloroborazine and
evaluation of 1H-NMR spectra
Abstract: ABSTRACT: The compound 2,4,6-trichloroborazine (TCB) is known as a valuable precursor to prepare boron nitride and various derivatives of borazine. Difficulties in the preparation of TCB via conventional methods on the one hand, and its importance for the material science, on the other hand, were our motivation to modify the Brown’s method for TCB synthesis. So far, all reports on the synthesis procedure of TCB are based on the use of gaseous BCl3 with NH4Cl powder at 110-130 °C in chlorobenzene requiring complicated low-temperature equipment such as a cold finger condenser, and dry ice-acetone reflux condenser to retain BCl3 gas in the reaction flask. According to our study, using BCl3 solution in n-hexane was more convenient than using gaseous BCl3. The reaction of BCl3 solution with NH4Cl was carried out without loss of BCl3. Furthermore, the reduction in the reflux temperature from 130 °C in some previous studies to 86 °C in our study, was a valuable advantage, leading to the release of the coordinated BCl3 from the adduct complex [CH3CN·BCl3] gradually and the prevention of thermal decomposition of TCB, unwanted polymerization reactions and the formation of undesirable products, resulting in the increased reaction yield. TCB was fully characterized by ATR-FTIR, 11B-, 14N- and 1H-NMR spectroscopic methods. 1H-NMR spectra of TCB were performed for the first time at various temperatures to elucidate the quadrupolar effect of nitrogen, which led to evaluate the splitting of the proton resonance of the 14N-H bond by coupling with the 14N quadrupole nucleus. The broad peak observed at room temperature was clearly split into a triplet at 100 °C due to the long TqN and fast molecular motion of TCB molecules. The 14N-NMR spectrum was also shown for the first time as a broad signal at δ = –271.3 ppm (h1/2 = 186 Hz).
- Mechanical and thermal performances of rubber/graphite-derivatives: facile
synthesis, characterization and formulation
Abstract: A larger scale production of graphene oxide (GO), reduced graphene oxide (rGO) and reduced GO decorated with SiO2 (rGO@SiO2) as graphite-derivatives are reported. The pristine graphite (Gt), synthesized rGO and rGO@SiO2 were dispersed in dioctyl phthalate (DOP) assisted using sonication technique. styrene butadiene rubber (SBR)-based elastomer was first formulated and the homogenized samples are loaded into the SBR polymer matrix using a Bunbury-type kneader. Common industrial-grade materials were used to synthesize additives and compound formulations, and loading the additives into the polymer was mechanically performed. From an economic point of view, it means this product could be easily commercialized. Fourier-transform infrared spectroscopy (FTIR) spectrum index bands of prepared GO and rGO@SiO2 were appeared at about 1725 and 1064 cm-1, respectively. X-ray diffraction (XRD) was used to study the crystal structure of the synthesized materials. Surface morphology of the synthesized materials and separation of pristine graphite compressed layers were verified with Transmission Electron Microscopy (TEM) images. Mechanical testes of the compounded products were showed good tensile stress, virtually two folds greater than blank rubber. Thermogravimetric analyses investigation showed that a clear improvement of thermal stability of composites increased with adding the synthesized carbon-based additives. The prepared rGO/SBR and rGO@SiO2/SBR composites exhibited higher oxidative-induction time (13.84 and 9.39 min, respectively) compared with blank SBR compound.
- Synthesis, DFT Calculations to investigate the Structure Electronic,
Absorption Electronic Spectra, Antimicrobial Activity Application, and
Non-Linear Optical Analysis of Pyridinyl and Pyrimidinyl Phosphonates
Schemes
Abstract: In this paper, the structure optimized and calculations electronic properties for the studied of two compounds which are 2 is Diethyl {5-[(2-hydroxy-5-methyl phenyl) carbonyl]-2-thioxo-1,2,3,4-tetrahydropyrimidin-4-yl} - phosphonate (2), compound 4 is Diethyl {6-amino-1-(4-chlorophenyl)-5-cyano-3-[(2-hydroxy-5-methyl phenyl)carbonyl]-1,2-dihydropyridin-2-yl]}phosphonate (4) have been performed by using to DFT the method at the B3LYP/6-311++G (d, p) theory level. UV-Vis spectra, in both methanol and dioxane solvents, have been employed for two compounds 2 and 4 by density functional time-dependent theory (TD-DFT) calculations at the same level of calculation. The method of Coulomb-attenuating (CAM-B3LYP) and Corrected Linear Response Polarizable Continuum Model (CLR) PCM studied for theoretically obtaining the absorption electronic spectra in the gas phase, methanol, and dioxane, respectively; indicate a good agreement with the observed spectra and FT-IR, vibrational spectra were calculated. The GIAO method calculated the 1H and 13C NMR chemical shifts theoretically values which reflect better coincidence with the experimental chemical shifts. The dihedral angles result of calculations show that two compounds 2 and 4 are non-planar. The stability of the two compounds 2 and 4, the hyper conjugative interactions, the delocalization of the atomic charges were analyzed with the Natural Orbital Bond analysis (NBO). The relocation of electronic density and the electronic structures were discussed. Studied functional density local descriptors, (MEP) Molecular Electrostatic Potential, molecular border orbitals, and absorption spectral. Analysis of the global descriptors revealed that compound 4 is the most reactive with an energy difference between the border orbital of ΔEgap = 3.605 eV. Furthermore, this compound 4 is the less stable, the softest, and has the greatest electronic exchange capacity of the other compound 2 studied. Studied by DFT calculations (SAR) structure-activity relationship and contacted with practical antimicrobial results for compounds 2 and 4.
- Optimization of the phenolic and antioxidants extraction from Ganoderma
Lucidum using ultrasound method
Abstract: The current study aimed to optimize the extraction conditions from Ganoderma (G) Lucidum mushroom by ultrasound in order to increase the extracted phenolics and antioxidant compounds. The impact of solvent type (water, methanol, and 50:50% combined solution of both), time (5, 10, 15 min ), and ultrasound intensity (100, 200, and 300 w ) on the extraction yield of phenolics and antioxidant compounds from G. lucidum mushroom were investigated. The response surface method(RSM) was used to optimize the extraction conditions.In the single optimization condition, the maximum total phenolics (36.6989 mg/ g) extraction yield from G. lucidum was achieved in 15 min extraction time, 300 w ultrasound power, and use of methanol solvent. The lowest IC 50 (0.8983 mg/ml ) was observed in the extraction time of 10 min, the ultrasound power of 300 w, and the use of methanol solvent. Multiple optimizations of extraction conditions from G. lucidum to achieve the highest total phenol (36.6989 mg/ g) and the lowest IC 50 (0.9413 mg/ ml) were predicted in 300 w ultrasound power, 15 min, and use methanol solvent. No significant difference was observed between the predicted and experimental results.
- Optimization the conditions of process of production of pectin extracted
from the waste of potato peel
Abstract: The objective of this study is to investigate the effect of three variables including temperature (35, 65 and 95°C), time (40, 120 and 200) and pH (1, 2 and 3) on the yield, galacturonic acid percentage and degree of pectin esterification extracted from the potato peels and optimization of the condition of extraction. Response surface method is used to optimize the conditions of extraction. Physicochemical properties of extracted pectin under optimum conditions were compared with commercial citrus and apple pectins by pectin flow behavior tests at different concentrations, FT-IR spectrum and pectin molecular weight. The results showed that the highest extraction yield was 14.87% at 95°C, 120 min time and pH 1. The highest percentage of extracted galacturonic acid pectin in potato peel was 36.37% at 95°C in 120 min and pH 1. The highest degree of esterification of extracted pectin from potato peel was 41.820% at 65°C in 40 min time and pH 3.00. Simultaneous optimization of extracting pectin with the aim of achieving maximum yield was galacturonic acid with 100% desirability at 95°C, 200 min time and pH 1 that in this condition, the yield was 15.23% and galacturonic acid was 38.0712%. The highest stability of extracted pectin emulsion from potato peel was observed at 4°C on the first day. Also, the FT-IR results showed that the strong absorption between 3200-3500 cm-1 in the extracted pectin sample was related to the intracellular and extracellular vibration of the hydrogen bond in the galacturonic acid polymer. The molecular weight of extracted pectin from potato peel under optimum conditions was 53.46 kDa after 30 days of storage at 4 and 23°C with emulsion stability 85.1 and 63.1, respectively. The results of this research showed that extracted pectin from potato peel can be introduced as a source of pectin to the market.
- Bromide Transport through Soil Columns in the Presence of Pumice
Abstract: Solute transport parameters, similar to soil physical and chemical properties, can be affected by the presence of organic and mineral soil conditioners. In this study, the effect of different levels (0, 3, and 6 weight percent) of the inexpensive and easily accessible pumice conditioner on the parameters of bromide transport in sandy loam soil columns (diameter and height of 10 cm) was investigated. The transport parameters were estimated based on the breakthrough curves (BTCs) by the inverse modelling of the convection-dispersion equation (CDE) and the mobile-immobile model (MIM) using the CXTFIT software. The BTCs showed that bromide transport in the sandy loam soil columns, regardless of the presence of pumice, was mainly equilibrium, and the CDE was more efficient than the MIM, which is based on non-Fickian and non-equilibrium transport. The peak of the BTCs (maximum relative concentration) was lower in the treatments containing pumice and belonged to more pore volume than the controlled treatment did. This indicates a lack of preferential flow and thus, a reduction in the amount of bromide consumed in the treatments containing pumice. The increase of pumice content did not have a significant effect on the parameters of mobile water fraction (β) and mass transfer coefficient (ω) in the MIM, confirming the equilibrium transport of bromide. A 3% increase in the pumice content in the soil caused an increase and a decrease of 47% in dispersivity (λ) and Peclet number (Pe), respectively. In general, it can be concluded that the use of pumice in field conditions can prevent water loss and nutrients and reduce groundwater contamination by reducing the preferential paths.
- Corrosion Inhibition Properties of Sulfonated Polyaniline-Poly(Vinyl
Alcohol) Composite on Mild Steel
Abstract: In this work, we demonstrate water based corrosion inhibition properties of engineered sulfonated polyaniline molecules on poly(vinyl alcohol), PANI-PVA, for mild steel. The corrosion-inhibition performances were evaluated using potentiodynamic polarization in salty corrosive 3 % NaCl solution. The anti-corrosion coating based on these composite materials display barrier properties against corrosion causing agents and show corrosion protection efficiency of 84.39 %, compared with uncoated. The material showed lower value of corrosion current (Icorr) that is 2.56 μA cm-2 and positive shift in corrosion potential (Ecorr), -0.426 V, in comparison with uncoated steel. Open circuit potential (OCP) Studies and electrochemical impedance (EIS) were also carried out to check the corrosion protection ability of the material. OCP studies, Nyquist plot and Bode plots showed that the synthesized PANI-PVA possess corrosion protection ability on mild steel against the corrosive species.
- Eco-Friendly Innovation for Electrical Conductivity Reduction of Persian
Gulf Sea water Using Highly Efficient Recyclable Sorbent
Abstract: The use of sea water containing of Reverse Osmosis effluent is very serious for the daily living of the coastal residents especially for farmers. In this study, one-year field test was carried for electrical conductivity reduction of Persian Gulf sea water in Iran, during 2017 and 2018. The test was conducted in two filters each with diameter 2.5 cm (or 0.025 m) and 18.5 cm (or 0.185 m). In the filters, crumb mineral mussel was used as one of main components from filter materials. The minor components of filter materials were comprised of coarse-grained gravel, fine-grained activated carbon, and fine-grained sand. The well water as low-saline water for background of sea water treatment and sea water as super-saline water were treated. The test was performed as pilot, batch, and column design with three replicates. The volume of daily treated sea water and efficiency of reduction electrical conductivity and salinity were determined. Volume of treated sea water by each of the filters was at least 10 times diameter each of those. Maximum reduction efficiency of electrical conductivity and salinity in filter with 2.5 cm (or 0.025 m) diameter was 97.09% (from 85.2 to 2.48 mS/cm or from 8.52 to 0.248 S/m) and it was 98.2% (from 61 to 1.1), respectively. Maximum reduction efficiency of the parameters in filter with 18.5 cm (or 0.185 m) diameter was 97.5% (from 84.8 to 2.12 mS/cm or from 8.48 to 0.212 S/m) and it was 97.69% (from 60.7 to 1.4), respectively. Electrical conductivity in outlet water from filters was less than 3 mS/cm (or 0.3 S/m), below the permissible limit recommended by World Health Organization and also Iranian Department of Environment for agriculture and irrigation usage. Based on these results a non-continuous method seems promising in the biological growing phase in filters.
- Estimation of pressure drop of single-phase flow in horizontal long pipes
using artificial neural network
Abstract: Large- pressure drop and drag along the pipe route is one of the problems with fluid transfer lines. For many years, various methods have been employed to reduce the drag in fluid transmission lines. One of the best ways for this purpose is reducing friction coefficients by utilizing drag lowering materials. Experimentally by adding minimal amounts of this material at the ppm scale to the lines and reducing the drag of the flow, fluid can be pumped without the need to change the size of the pipe. In this study, the effect of carboxymethylcellulose biopolymer on the water flow reduction in a 12.7- and 25.4-mm galvanized pipe was investigated. In order to have a comprehensive analysis of process conditions, experiments were carried out with three different levels of concentrations, flow rate and temperature. Also, as a new innovation in this investigation, the outputs of the experimental data were evaluated and analyzed using the Taguchi method and neural network system, and optimized through a genetic algorithm. In this study, the highest rate of drag reduction will be achieved at 39 ° C and at a concentration of 991.6 ppm and flow rate of 1441.1L/h was 59.83% at 12.7-mm diameter.
- Optimization of Chalcogenide CdTe, CZTS and CZTSe Solar Cells
PerformancesUsing Cd1-xZnxS Buffer Layer
Abstract: Cadmium zinc sulfide (Cd1-xZnxS) as a wide-band gap material with x=0.7 was used inthe present work as an alternative buffer material to CdS to improve the efficiency ofZnO/Cd1-xZnxS/CdTe, ZnO/Cd1-xZnxS/CZTS and ZnO/Cd1-xZnxS/CZTSe thin film solar cells. The photovoltaic parameters such as efficiency, open circuit voltage (Voc), short circuit current density (Jsc) and the fill factor (FF) have been computed using one-dimensional simulation programs such as Solar Cell Capacitance Simulator (SCAPS v3.3) and Analysis of Microelectronic and Photonic Structures (AMPS-1D). An improvement in conversion efficiency isnoticed compared to the structure with the CdS buffer layer. It is found that the efficiencies of Cd1-xZnxS/CZTSe and Cd1-xZnxS/CdTeareincreased from 12.61% to 15.35% and from 17.53% to 18.83%, respectively. The simulations were performed for 1 µmthick absorber layers.It is also found that the efficiency rises from 12.53% to 13.23% with Cd1-xZnxS/CZTS structure for CZTS thickness of 2.5 µm. Moreover, the quantum efficiency (QE) characteristics display the maximum value of more than 80% in the visible rangeand the structures presented a slight improvement in the short wavelength. The present study shows that the suggested structures with aCd1-xZnxS buffer layer may improve the efficiency and reduce the amount of Cd, which is a toxic element.
- The Modelling of the Urea Fertilizer Dissolution Process in
Finite/Infinite Volumes of Water
Abstract: This research aims to provide a model to investigate the impact of some parameters such as impeller speed, temperature, and solid concentration on mass transfer coefficient and the dissolution rate of urea fertilizer in the water. To study the effect of solid concentration two models are presented for finite and infinite volume fluids using mass balance. Then the urea-water mass transfer coefficient was calculated at various impeller speeds and temperatures by measuring the time to complete dissolution. To investigate the effect of impeller speed and turbulency on the mass transfer coefficient, the impeller speed and Reynolds number were set in a range of 10-50 [rpm] and 300-3000, respectively. The Schmidt number also was used to study the effect of temperature on mass transfer coefficient in the range of 5-25[°C]. The results show that in both finite and infinite fluid volumes, at a constant impeller speed with decreasing Schmidt number, and at a constant temperature with increasing Reynolds number, the mass transfer coefficient, and mass transfer rate increase. Furthermore, four models are presented for mass transfer coefficient in finite and infinite volume, that show the mass transfer coefficient and release rate in finite volume were lower than that of infinite volume at a constant impeller speed and temperature.
- The non-dimensional analysis of heat transfer and fluid flow in wavy mini
channel heat exchangers
Abstract: In this research, the heat transfer behavior of a wavy mini channel heat exchanger was studied. Using the experimental data of heat transfer, the convective heat transfer coefficients were estimated. Among numerous trails, Nusselt number (Nu) best correlation is a linear function of Reynolds number (Re) independent of Prandtl number (Pr), and the similar correlations for hot and cold sides were obtained. The coefficient range is 0.01 to 0.03 for different fluids. The previous experimental works verify this conclusion. Also, in the case of non-Newtonian fluids and nanofluids, the definition of Re is related to its rheological behavior. However, if the velocity profile is specified, it can be used to derive the relation between the Fanning friction factor (Cf) and Re. Here, a suitable velocity profile for wavy configuration is used and the experimental values of Re are estimated by the experimental pressure drop data. It is shown that the application of the derived relation between Cf and Re is preferred compared to the assumption of a circular pipe that is convenient for fluid mechanics studies. In addition, it is proved that if experiments with different fluids or relative waviness are done at similar flowrates, the U versus the Re plot can be used to compare heat exchanger performance.
- Comparative Study of Thermal Waste Recovery Systems Deployed in Three
Different Chemical Units
Abstract: Waste thermal energy is enough amount of energy that is rejected to the atmosphere in the form of flue gases, streams of air, and liquid rejected from industries. It arises from the equipment, less efficient processes, and limitations due to the laws of thermodynamics on operations. It is obvious that it is not possible to regenerate all waste energy but most of the time some waste heat can be used to achieve useful purposes. Waste heat recovery is the most important key to carry out most of the research areas. The major areas of research and it is necessary to make the process more energy-efficient in chemical industries. To save energy Heat Exchanger Network’s synthesis (HEN) is essential. They are designed to reach energy targets. HEN design is the thermal integration between cold and hot utilities by pinch analysis at minimum temperature difference. HENs are important for utility saving because it helps in recovering heat from hot streams to others which reduces the utility consumption and requirement. The heat exchangers design with simplified models for different industries using pinch technology by which most thermal recovery is obtained and then some HEN network is required for a particular targeted area. In this research improvements in energy recovery systems and HENs, synthesis helps in capital savings and pollutant emission can also be reduced.
- An Inclusive and Effective End-of-Life Vehicle Recycling System in India:
Balancing Economy and Ecology from Grave to Cradle
Abstract: End-of-Life Vehicles (ELVs) in India are often recycled by car breaking yards operating in the informal sector. In the absence of well-established, state-of-the-art ELV mechanisms, their work – ensures crucial recycling of ELVs. Multiple qualitative analysis methods, such as desk study, literature review, and field visits, are utilized. Our study shows the following: car breaking yards frequently work in an inefficient manner causing environmental hazards and health risks; the replacement policy adopted during vehicle servicing by Original Equipment Manufacturers and Authorized Dealers results in inefficient material use; Informal actors such as Private workshop owners and Reconditioning shops enable significant savings in material and costs, partly by substituting capital and energy with labour. We propose an inclusive 3R (reuse, recondition, and recycle) framework, which integrates various informal actors involved in ELV recycling. This sustainability-oriented framework ensures that the components and materials circulate in a closed loop.
- Graphitic carbon nitride nanosheet as an excellent compound for the
adsorption of calcium and magnesium ions: theoretical and experimental
studies
Abstract: In this work, the removal of calcium (Ca2+) and magnesium (Mg2+) ions were studied using graphitic carbon nitride (g-C3N4) nanosheet as an adsorbent from aqueous solutions. In experimental studies, the effects of various adsorption parameters were investigated by batch method culture including pH, initial Ca2+ and Mg2+ concentrations, temperature, time, and adsorbent mass. The best results were obtained at pH=8.50, 0.05 g of g-C3N4, 90 min, 10 ppm of ion concentration, 23.80 mg g-1 of maximum adsorption capacity for Ca2+, and pH=9, 0.05 g of g-C3N4, 60 min, 15 ppm of ion concentration, 40.00 mg g-1 maximum adsorption capacity for Mg2+ ion. The adsorption of calcium and magnesium ions obeyed the Langmuir model on adsorbent. In theoretical study, g-C3N4 nanosheet as an interesting material was studied by first-principle calculation using the Quantum Espresso package. The Ca2+ and Mg2+ ions were located at different positions on g-C3N4 nanosheet to obtain the stable configuration. The Eads, HOMO, LUMO, Eg, band structure, DOS and PDOS plots were investigated at stable configuration of g-C3N4 nanosheet. The adsorption energy (Eads) was calculated -15.55 and -26.24 eV for Ca2+ and Mg2+ ions, respectively. Further, the results indicated that Mg2+can be located at the center of the porous g-C3N4 nanosheet, which the adsorption of Mg2+ on surface of g-C3N4 nanosheet was stronger than that of Ca2+ ion. Theoretical and experimental data confirmed each other’s findings. The adsorption of Ca2+ and Mg2+ ions was shown to be simple, high-yield, eco-friendly, and economical performance from aqueous solutions using g-C3N4 nanosheet
- An Electrochemical Sensor Based on Multi-Walled Carbon Nanotubes
Functionalized With 2-Picolinyl Hydrazide for Electrochemical Detection of
Pb(II) Ions
Abstract: An new electrochemical sensor was constructed with the nanometer coaxial cable, which was prepared based on Multi-walled carbon nanotubes (MWCNTs) and pyridine. the analysis of trace Pb(II) with differential pulse anodic stripping voltammetry (DPASV) was studied. The MWCNTs–TPI–2–Ph was characterized by SEM, TEM and electrochemical method. Various parameters such as deposition time, pH values, deposition potential, interference experiment, stability and reproducibility were invesitgated. DPASV was used for evaluating the detection of trace Pb(II) based on the accumulation process. Under the optimal conditions, the MWCNTs–TPI–2–Ph/GCE showed excellent stripping response of Pb(II) in the ranges of 1 to 100 μmol L-1, the peak currents linearly increased with the concentration of Pb(II). The detection limit was calculated to be 0.03 μM (S/N=3). Detection mechanism toward Pb(II) based on MWCNTs–TPI–2–Ph/GCE was proposed. Therefore, it was important to design an electrochemical sensor based on new metal ions capture reagent.
- Polyacrylonitrile/Ag nanoparticles nanofibers as an efficient adsorbent
for natural gas condensate desulfurization
Abstract: In this work, the optimization of the synthesis of PAN/Ag nanofiber composites via electrospinning was investigated via Taguchi experimental design approach. The adsorption capacity of sulfur compounds from natural gas condensate was considered as an objective function. The PAN/Ag nanofiber with 11 wt% PAN, 45 wt% AgNO3, 15 kV applied voltage, and 15 cm for distance of needle to a collector showed the highest adsorption capacity. The SEM, EDX, TEM, XRD, and FT-IR techniques were employed to elucidate the optimized PAN/Ag nanofiber structure. The results showed the successful synthesis of PAN/Ag nanofibers with diameters in 100-300 nm range and well distribution of Ag nanoparticles in the polymeric matrix. In addition, optimization of the adsorption capacity of PAN/Ag nanofiber in desulfurization of natural gas condensate in batch mode was performed via central composite design. Four factors including adsorbent weight, sulfur concentration in the natural gas condensate, the volume of sample, and the adsorption time were considered as effective factors each in three levels. The ANOVA analysis showed the more important factors on adsorbent performance are the concentration of sulfur in gas condensate and the weight of the adsorbent. The interaction terms between time and concentration and between volume and concentration are also important in response. Moreover, the response surface analysis of interaction terms showed the adsorptive nature of desulfurization.
- Tuning structural and optical properties of copper oxide nanomaterials by
thermal heating and its effect on photocatalytic degradation of Congo Red
dye
Abstract: In this study, Copper oxide (CuO) nanoparticles (NPs) were prepared using the chemical co-precipitation method and treated at different calcination temperatures. The synthesized CuO NPs have been calcinated at 300 °C, 500 °C, and 700 °C. The X-ray Diffraction (XRD) results exhibited a decrease in the width of the principle diffraction peak with the temperature rise. Crystallite size was determined by Scherrer’s formula, whereas, Williamson-Hall method presented drastic variation in size indicating the creation of lattice strain with the rise in calcination temperature. Scanning Electron Microscopy (SEM) images showed an increase in grain size and vary from 170 nm – 430 nm. X-ray Energy Dispersive Spectroscopy (EDS) results indicate the formation of CuO NPs and relative Cu contents increased (52.9 to 72.5 Atomic percentage) with temperature. Optical properties are also affected by the calcination temperature and a reduction in bandgap is observed with the increase in temperature. Fourier Transform Infra-red spectroscopy (FTIR) spectra of different samples showed identical bonding behavior and no apparent change in bonding was observed. Photo-degradation of Congo Red dye was performed with CuO NPs treated at different temperatures and NPs treated at 500 °C, have shown maximum degradation efficiency in 75 min under visible light.
- Potential improvement in photo reduction of towards Cr(VI) species from
aqueous solutions onto an heterogeneous Na-Clay/Fe2O3 catalyst
Abstract: Clays in the soils are a natural barrier against pollution. A representative sample of clay (illite) from Algeria is collected and analysed by XRD. The results show that this sample is an illite containing calcite and quartz as impurities. We also analysed the clay by SEM, EDS and BET, and modified it by chemical treatment with NaCl in order to increase its specific surface area with insertion of Na+ cations into the inter-foliar space. The study of Cr(VI) ions adsorption onto Na-Clay was performed. The influence of Cr(VI) initial concentration, pH of solution, temperature and solid/liquid ratio were studied. Among the tested models, the equilibrium data well fitted by the Langmuir isotherm. The maximum Cr(VI) adsorption rate was 44% at 25°C with limited capacity adsorption of 10 mg/g. The adsorption kinetic is best described by the pseudo second order model. The Cr(VI) ions reduction onto Na-Clay/Fe2O3 and the effect of the same parameters were also performed. The maximum of reduction (98%) was reached at pH = 2, T = 25°C, [Cr(VI)] = 50 mg/L and S/L = 1 mg/mL. It was found that the reaction follows first pseudo order rationalized well by the Langmuir-Hinshelwood (LH) model. The evaluation of the thermodynamic parameters (ΔG°, ΔH° and ΔS°) revealed that chromium (VI) adsorption and reduction were endothermic and exothermic respectively.
- Numerical Implementation of Electrokinetics for Removal of Heavy Metals
from Granite Waste
Abstract: The goal of the study is to incorporate the electrokinetic models and estimate the remediation time for maximum removal of heavy metals (HMs) from polluted soils. Most of the conventional electrokinetic technologies have not considered the electrokinetic models in the removal of HMs from polluted soils. We addressed this problem and incorporated the electrokinetics and applied for experimental Electrokinetic Soil Remediation (EKSR) process particularly, to extract the numerical data between removal performance of HMs versus remediation time with help of the MATLAB program. In the experimental study, chelating chemical agents (citric acid and ethylenediaminetetraacetic acid (EDTA)) were used in EKSR process under constant voltage gradient (2V/cm) for the removal of Chromium (Cr), Cobalt (Co), Nickel (Ni), Copper (Cu), Zinc (Zn) and Manganese (Mn) ions from granite dump soil. We experimentally investigated that the removal performance of HMs in chelating agents enhanced EKSR were about 6 to7 times more than when unenhanced in 20 days of treatment. Furthermore, we estimated the remediation time about 52 to 54 days for complete removal of HMs using electrokinetic models. The study may be useful for the researcher’s particularly, in the soil decontamination studies to overcome the uncertainty in the process optimization and scale-up the process to the pilot plant and field level.
- Adsorption of Textile Dyes on Willow tree Pollen: Determination of
Equilibrium, Kinetic and Thermodynamic
Abstract: In this study, the characterization and adsorption properties of Brilliant Cresyl Blue (BCB- ALD) and Acid Blue-25 (AB-25) dyes were investigated using willow tree pollen, a low-cost natural adsorbent. All adsorption tests were performed in consideration to contact time, adsorbent concentration, adsorbent dosage and temperature functions. Equilibrium isotherms were explained in terms of the Langmuir, Freundlich, Temkin, and Dubinin Radushkevich (D-R) linear adsorption equations. It was found that adsorption complied with the Langmuir equation. Moreover, pseudo first order, pseudo second order, and intraparticle diffusion models were used to determine kinetic data. Experimental data showed a match with pseudo second order kinetic model. Thermodynamic parameters such as enthalpy, Gibbs free energy, and entropy were examined for willow tree pollen samples. The data obtained leads us to the conclusion that adsorption is a spontaneous process. On the other hand, positive enthalpy indicates that adsorption is endothermic. Positive entropy values are a result of changes on the adsorbent surface. Characteristic results and dimensionless separation factors (RL) indicate that pollen can be used as an alternative to commercial adsorbents to remove BCB- ALD and AB-25 from aqueous solution and wastewater.
- Response surface modeling of the Removal of Methyl Orange Dye from Aqueous
Solution using Magnesium Oxide Nanoparticles Immobilized on Chitosan
Abstract: In this work, the chitosan-based magnesium oxide nanoparticles (CS-MgONP) composite was used as an adsorbent for the removal of organic dye methyl orange (MO). The adsorbent characterization was carried out using X-ray diffraction (XRD), Field emission scanning electron scanning microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy. The faster equilibrium, i.e. at an agitation time of 30 min, indicated the faster adsorption capability of the prepared adsorbent CS-MgONP. The central composite design (CCD) of response surface methodology (RSM) was used to evaluate the impact of process parameters in the range of pH (6-10), CS-MgONP dosage (0.1-0.5g/L), MO concentration (10-30mg/L), and temperature (283-323K) at an optimal agitation period of 30 min. Under optimum conditions of pH=7.93, CS-MgONP dosage=0.4g/L, initial MO concentration=15mg/L and temperature=313 K, 96.42% removal of MO was achieved with a desirability of 0.805. The adsorption of MO onto CS-MgONP was best fitted with the Langmuir adsorption isotherm, with an uptake capacity of 237.5 mg/g and followed the pseudo-second order kinetics. The thermodynamic studies showed positive enthalpy and negative Gibbs free energy that confirmed the spontaneous and endothermic process. Due to the fast equilibrium agitation period, i.e.30 min and high adsorption capacity, the adsorbent CS-MgONP proved to be an excellent choice for dye removal.
- Reducing Nitrate from Water Using Lanthanum-modified Adsorbent:
Optimization, Thermodynamics, Kinetics, and Isotherms
Abstract: Lanthanum-modified commercial activated carbon (LMAC) adsorbent was synthesized, characterized, and then applied for reducing nitrate from aqueous solutions under various conditions. The extent of nitrate removal depended on four factors: temperature, the aqueous solution pH, initial nitrate concentration, and contact time. The Taguchi approach was used as the method of design for the experiments. Under optimal conditions ( T= 300°C, pH=3, C0=10 ppm, and t= 210 min), the removal percentages and capacity of nitrate adsorption were found to be 71.31%, and 1.43 for activated carbon (AC) and 93.31% and 1.87 for LMAC, respectively. Thermodynamic parameters, including the enthalpy, Gibbs free energy, and entropy, indicated the spontaneous and exothermic nature of the adsorption process. Various isotherms and first and second-order kinetic models were applied to investigate the adsorption process. The pseudo-second-order kinetic model and Langmuir isotherm could well describe the adsorption process.
- Isolation of Jatropha curcas Oil Based Linoleic Acid By Using Argentation
Column Chromatography
Abstract: Argentation column chromatography is a method used for separating similar molecules such as fatty acids which have a slightly different in stereochemistry. In this study, silver nitrate-impregnated silica gel was used as the adsorbent to isolate and purify Jatropha curcas oil fatty acids mixtures. The effects of silica gel, silver nitrate, adsorbent quantity and fatty acid quantity on the purity and recovery percentage as well as ratio of linoleic acid to oleic acid were investigated. The results showed that at optimal condition of purification, the purity of linoleic acid increased from 38.4% to 78.7%. In the isolation process, linoleic acid adsorbed most strongly on the AgNO3/SiO2 adsorbent followed by oleic acid due to greater number of double bond and high ability to form polar charge-transfer complexes.
- Synthesis, Characterization and DFT Calculation of some New Pyrimidine
Derivatives and Theoretical Studies on the Corrosion Inhibition
Performance
Abstract: In this study, 5-benzoyl-6-phenyl-4- (4- (trifluoromethoxy) phenyl) - 1,2,3,4-tetrahydroxypyrimidine (1); 5-benzoyl-6-phenyl-4- (4- (trifluoromethoxy) phenyl) -1,2,3,4-tetrahydrothioxypyrimidine (2) and 5-benzoyl-6-phenyl-4- (3,5-dimethoxy) phenyl) -1,2,3,4- tetrahydrothioxypyrimidine (3) compounds were prepared via Biginelli condensation reaction used Metal-organic framework (MIL-101) as active catalyst. It was established to be an active heterogeneous catalyst for three component Biginelli condensation reaction with good yields (75-80 %). Moreover, the catalyst could easily be recovered and recycled without any significant loss of its catalytic activity. Also the compounds 5-benzoyl-6-phenyl-3-acetyl-4-(4-hydroxyphenyl)-1,2,3,4-tetrahydrothioxypyrimidine (4) and 5-benzoyl-6-phenyl-3-acetyl-4-(4-trifluoromethoxy)phenyl)-1,2,3,4-tetrahydrothioxypyrimidine (5) were obtained acetylation reaction. The structures were characterized on the basis of 1H-NMR, 13C-NMR, FT-IR, and elemental analysis. And also molecular characterizations of compound 4 were analyzed by X-ray crystal analysis. In addition, the corrosion inhibition activity of synthesized compounds was examined with theoretical calculation using DFT method at the level of B3LYP / 6-31G (d, p).
- D-Optimal Design Optimization for Esterification of Palm Fatty Acids
Distillate with Polyhydric Alcohols for Biolubricants Production
Abstract: Plant-based biolubricant is crucial to be developed and adopted for many industries. This is due to the presence toxicity risk, climate change, energy security as well green-environmental approach issues. The utilization of palm oil processing industries by-product, palm fatty acid distillate (PFAD-based biolubricants is one way of green environment approach. A synthesis of polyol esters based on PFAD for biolubricants was carried out. The esterification of PFAD with high degree polyhydric alcohols trimethylolpropane (TMP), di-trimethylopropane (di-TMP), pentaerythritol (PE) and di-pentaerythritol (Di-PE) in the presence of sulphuric acid (H2SO4) catalyst have been performed. The optimization of the esterification reaction process was evaluated using D-optimal design based on three reaction parameters; H2SO4 concentration (%) for the catalyst, esterification time (h) and esterification temperature (°C). The chemical structure of the synthesized polyol esters was characterized and confirmed by using FTIR and NMR (1H and 13C) spectroscopies. The results showed that PFAD-based polyesters of PFAD-TMP ester successfully produced in high yields of 93% compared to others. The synthesized PFAD-based polyesters showed good lubrication properties with high viscosity indices in the range of 141-187, pour points (-5 to 5 ºC), flash points (230-360 ºC), and oxidative stability temperature (188-301 °C), respectively. The ester functional group presence in their chemicals structure of PFAD-based polyesters showed positive impact on the lubrication properties. The study indicated that the PFAD-based polyesters are plausible to be used as industrial biolubricants application.
- Green Synthesis and Characterization of Zinc Pyridine-2,6-Dicarboxylate
Complex and Preparation of Nano-ZnO by Thermal Decomposition
Abstract: A complex [Zn(Hpda)2]•2H2O of pyridine-2,6-dicarboxylic acid (H2pda) was synthesized by a green chemistry approach, namely, room-temperature solid state reaction. The complex was characterized by elemental analyses, powder X-ray diffraction (PXRD), single crystal X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), and thermogravimetry and differential scanning calorimetry (TG-DSC). The PXRD result confirmed that the unpurified powder complex was single phase. The crystal structure of the complex belonged to monoclinic system with space group P21/c, and the Zn(II) ion was hexacoordinated by four O atoms and two N atoms. The thermal decomposition of the complex was investigated and the nano-ZnO particles were prepared by pyrolysis of the unpurified powder complex as the precursor. The ZnO particle obtained by pyrolysis at 500 °C was characterized by PXRD and scanning electron microscope (SEM), and its average diameter was about 40 nm.
- Rapid simultaneous spectrophotometric determination of food dyes in soft
drink using continuous wavelet transform and multivariate calibration
methods
Abstract: In this study, the spectrophotometric technique along with chemometrics methods have been developed for the simultaneous determination of sunset yellow (SY) and tartrazine (TZ) in mixtures and soft drink without any prior separation or purification. The first method is the continuous wavelet transform (CWT), in which various wavelet families were investigated. Eventually, the Gaussian wavelet family of second-order with a scaling factor of 5 for SY and the Daubechies wavelet families of the second-order with a scaling factor of 64 for TZ were selected. Both dyes showed good linearity, with the coefficient of determination (R2) of 0.996 and 0.9981 for SY and TZ, respectively. The limit of detection (LOD) and limit of quantification (LOQ) values were 0.1794, 0.0003 ðœ‡gmL−1 and 0.6066, 0.0983 ðœ‡gmL−1 for SY and TZ, respectively. On the other hand, multivariate calibration methods, including partial least squares (PLS) and principal component regression (PCR) were studied. The PLS recovery range was obtained from 100.06% to 103.06% and 100.86 to 103.49 for SY and TZ, respectively. Also, the mean recovery (%) of the PCR method were 101.41 and 102.90 for SY and TZ, respectively. In addition, values of RMSE related to the PLS and PCR were achieved 0.2578, 0.3023 and 0.2635, 0.5602 for SY and TZ, respectively. High-performance liquid chromatography (HPLC) as a reference method was applied for the soft drink, and the results were compared with the proposed methods using a one-way analysis of variance (ANOVA). There was no significant difference between them.
- A Comparative Study of Labetalol via Electrochemical and Computational
Methods
Abstract: Normodyne is the brand name of Labetalol. It has medicinal importance and well known antihypertensive drug and given to the patient in the severe hypertension condition. It is two-fold alpha and beta adrenergic antagonism and has dissimilar physiological effects in acute condition of high blood pressure. Various techniques were used to elaborate the qualitative behavior of this drug. In present work, Cyclic Voltammetry (CV) is used to determine the qualitative characteristics of Labetalol. The Glassy Carbon Electrode (GCE) is used as a working and Calomel as a reference electrode with supporting electrolyte (0.1M NaOH) at 30±1oC. In case of GCE, single anodic peak is observed which indicate that this drug showed irreversible process with transfer of one electron in the selected medium. In addition, different electrochemical parameters are also calculated including, peak current (Ip), peak potential (Ep), half peak potential (Ep/2), differential peak potential ΔEp = (Epa – Ep/2), transfer coefficient (α), diffusion coefficient (D), formal potential (Eo), heterogeneous rate constant (Ko), and Gibbs free energy (∆G). Furthermore, adsorption process is also studied. For comparative study, computational methods are employed for finding HOMO-LUMO energies and vibrational frequencies of Labetalol molecule. Both methods, electrochemical and computational are in good agreement and validate irreversible oxidation of Labetalol. This study has not been reported before and it is useful for pharmaceutical industry.
- Measurement and modeling of mean activity coefficients in ternary
electrolyte system (Nicl2/Triton X-100/H2O) at T=298.15 ± 0.1 K
Abstract: In this work, the results relating to the thermodynamic properties for the ternary electrolyte system of (NiCl2 + Triton X-100 + water) using the potentiometric method were reported at T = 298.15 K. The electromotive force measurements were carried out on the galvanic cell without liquid junction of the type: Ni2+-ISE NiCl2 (m), Triton X-100 (%wt.), H2O (100-%wt.) AgCl Ag over total ionic strengths from 0.0010 to 6.0000 mol.kg-1 for different percentage mass fraction of Triton X-100 (%wt. = 0.0, 1.0, 2.5, 5.0, 7.5 and 10.0). The mean activity coefficients of NiCl2 were determined by using potentiometric data. Then, the mean activity coefficients of NiCl2 were correlated with Pitzer ion interaction model and TCPC model. The Pitzer ion-interaction parameters (βo, β1 and C^∅) and the adjustable parameters (b and S) of TCPC model were determined by correlating of data for the series under investigated system. The Pitzer ion interaction parameters were used to calculating of thermodynamic properties such as the osmotic coefficients and the excess Gibbs energy of solution. The result showed that the Pitzer ion interaction model could be used to investigation of the system, successfully.
- Evaluation of the residence time distribution (RTD) for flow in ducts with
velocity profile of two independent variables
Abstract: The correct information on RTD can help in system design and evaluation. The RTD corresponding to the velocity profile is known only for certain cases, where the velocity profile depends on one coordinate only. In this research, a general procedure for derivation of RTD corresponding to a known velocity profile is introduced. The RTD of laminar flows in different ducts as elliptic, equilateral triangular, moon-shaped and rectangular ducts are derived. Also, it is shown that the final RTD for laminar flow in any duct, can be estimated using relation E(θ) = K θmin/θn that is similar to laminar flow in the pipe, with their own dimensionless minimum time, , where is defined as the required time for traveling the duct with the maximum velocity in unit of the space-time. The values of K and n is calculated to meet the condition of . Besides, the values of for different cross-sections are studied. The results show that the RTD of elliptic ducts is precisely similar to the pipe flow. In the case of other shape ducts, the proposed model shows a suitable estimate of the numerical values. The previously published experimental data and precise analytical solutions agree with the proposed model with an acceptable consistency, except for very little time say θmin < θ < 0.7.
- A numerical study for the effects of narrow channel dimensions on pressure
drop and mass transfer performance of a mixer device
Abstract: The numerical study in this paper investigates the effect of inlet and outlet areas of micromixer channels on fluid flow behavior and mass transfer performance. The ratio of outlet to junction area is varied from 0.6−2 while the ratio of inlet to junction area is from 0.6−1.4. The flow patterns obtained for various mixers indicate that vortices or recirculation zones are created as the two fluids turn and enter into the outlet channel. The formation of recirculation regions results in enhanced mixing rates. The micromixers are evaluated in terms of mixing quality, pressure drop and mixing effectiveness parameters. The mixing quality increases up to 10 times when the outlet area ratio increases from 0.6 to 2. The rise in pressure drop due to the increased outlet area is about 50%. The inlet area also influences the mixing rate and pressure drop. The mixing quality first increases and then decreases with an increase in area. The pressure drop, whereas, continuously decreases when the inlet area ratio increases from 0.6 to 1.4. Suitable dimensions of micromixer are suggested based on mixing effectiveness. A mixer device with an outlet/junction area ratio of 1.2 and an inlet/junction area ratio 0.8−1 is found to provide better performance.
- Identification of Coating Thickness in Cement Rotary Kiln
Abstract: The cement industry is one of the major industries in every country. This industry is the driving force behind the development of a nation. The heart of this industry is the rotary kiln. One of the significant concerns about a rotary kiln is forming a cover of molten materials on the kiln's inner wall called coating. The low thickness of this coating cause burns to the wall refractory bricks and heavy damage to the kiln, while its high thickness reduces the production volume and quality of products. Currently, the kilns are checked by experienced technicians for empirical coating estimation. This paper aims to identify the thickness of the coating for the automatic control purpose of the kiln. The identification problem of coating thickness is based on thermal resistances in different layers of the kiln and heat transfer equations between these layers. For this purpose, the linear and nonlinear identification methods such as Ordinary Least Squares (OLS), Recursive Least Squares (RLS), global search method, and genetic algorithm are used. The coating can be identified in the proposed identification approach by having the kiln's ambient and internal solid temperature profiles. The raw data for the identification process has been extracted by Finite Element Analysis (FEA) for a given solid temperature profile along with the kiln and different kiln coating thicknesses. The modeling and simulations carried out in this paper show that the identification methods were able to determine the amount of coating with acceptable errors depending on the method.
- Effect of small molecule compounds on the pyrolysis behavior of coal
Abstract: The effect of small molecule compounds on the pyrolysis behavior of coal are discussed by comparing TG and DTG curves of Yanzhou coal and its tetrahydrofuran (THF) extracted residual in this paper. Based on the thermal gravimetric analysis of Yanzhou coal and its THF extracted residual, it is revealed that part of chemical bonds are weakened after the small molecular compound are extracted in coal, which promotes the pyrolysis of its THF extracted residual. The optimum reaction temperature is 490 oC for the high temperature fast liquefaction of the THF extracted residual. The maximum temperature of weight-loss rate for Yanzhou Coal and its THF extracted residual is 439 oC and 437 oC, respectively. The liquefaction reaction temperature of them is 389-490 oC and 380-525 oC,respectively. The results we studied could can give some help to the further perfection of the theory of the pyrolysis behavior of coal, and its application. And it is further helpful to study the mechanism of the theory of the pyrolysis behavior of coal.
- Treatment of Direct Red 23 in recirculating semi-pilot system by O3/UV
process: Operational parameters effect and central composite design
modeling
Abstract: The treatment of C.I. Direct Red 23 (DR23) solution has been investigated by the ozonation under UV irradiation (O3/UV) in a recirculating semi-pilot mode. Decolorization efficiency (DE%) of DR23 was compared using the O3 and O3/UV processes, which was74.9% and 92.7% after 30-min treatment of the dye (100 mg/dm3), respectively. Then, the effect of experimental parameters on the O3/UV process including initial dye concentration, ozone mass flow rate and initial pH was studied. The obtained results revealed that the decolorization efficiency increased by enhancement of ozone amount and decreasing of the DR23 concentration; the decolorization process was performed efficiently at the basic condition (pH= 10) due to the production of extra hydroxyl radicals. The pseudo-first order kinetic was observed for the dye decolorization. Electrical energy per order decreases using the O3/UV process at the desired pH 10 indicating adequate synergistic effect of the photolysis and ozonation. Eventually, central composite design (CCD) approach was properly applied for prediction of the DE% with appropriate performance (R2 = 98.52%) and optimization of the process.
- Roughcast analysis as a new method of environmental research
Abstract: The aim of this study is to show purpose of roughcast analysis as a new useful tool for research of the condition of the environment. Samples of roughcast were collected from buildings in 6 different cities of Europe (Cracow, Lublin, Warsaw, Lviv, Monchegorsk and Murmansk) and their compositions were examined with scanning electron microscope, ICP-OAS and ASA methods. Also, binocular magnifier was used. The samples were investigated for heavy metals presence. The result shows that despite the deposition of particles is bigger on horizontal surface, the vertical layer of roughcast accumulate significant amounts of impurities and heavy metals. The composition and content of metals differ accordingly to automotive traffic nowadays and in the past, existence of road hubs, industrial districts and historical manufactures. Samples from Cracow show high content of non-ferrous metals and nickel, whereas content of copper was significantly higher in Monchegorsk. In Lublin and Lviv, their agricultural past contributed to significantly lower heavy metal content Determination of heavy metals contents in roughcast can be used to evaluate anthropogenic impact in the cities through the years and to help to protect cities’ population from negative consequences of living in urban areas.
- The Effect of formetanate hydrochloride on the glycated human hemoglobin
Abstract: ABSTRACTGlycation refers to the nonenzymatic glycosylation of the free amino groups of proteins and sugars. Advanced glycation end products (AGEs) is the final stage in glycation process. AGEs cause many complications in diabetic’s patients. Formetanate hydrochloride is a highly effective pesticide widely used in agriculture. Hence, all human beings, both healthy and diabetics affected patients, can be exposed to this toxin. Therefore, the purpose the present research is to study, the effect of Formetanate hydrochloride upon the glycated human hemoglobin (GHb). To form glycated hemoglobin, Hb was incubated with glucose for 35 days under physiological conditions (dark, 37Ċ and pH 7.4). The effect of the toxin on GHb was investigated via docking studies, flurometry, and UV-Vis and circular dichroism spectroscopy. Incubating Hb with glucose could degrade the structure the protein. Samples contained GHb and formetanate hydrochloride showed remarkable changes in structure; Heme-group degradation and an increase in β-sheet structures was also observed. The results of docking studies were consistent with these results. As diabetes is rapidly expanding in today's world and formetanate hydrochloride is widely used in agriculture, the impact of this toxin on these patients will be very important. According to the results obtained, this toxin can have more destructive effect on the glycated Hb in these patients.
- Studying the effect of pH, different concentrations of glutamic acid and
salt on non-protein nitrogen compounds, survival and overall acceptance of
low-fat probiotic cheese
Abstract: Today, the demand for low-fat dairy products such as cheese has increased. Reducing fat in cheese reduces the sensory properties of cheese. The use of probiotic bacteria, fat alternatives and changes in production methods can improve the sensory properties of low-fat cheeses. The aim of this research is to investigate the effect of three independent variables including pH (4.7, 4.9 and 5.1), glutamic acid (1, 2, 3 mgg-1) and salt (2, 2.5 and 3%) on the amount of non-protein nitrogen compounds to total nitrogen, survival and overall acceptance of low-fat probiotic cheese during for 30 days’ storage. According to the results, the amount of non-protein nitrogen compounds to total nitrogen is increased during the ripening period in all samples, but this increase in the sample containing 2 mgg-1 glutamic acid, 2% salt and at pH 4.7 is significantly higher than other tested samples. The results are shown that with increasing the amount of glutamic acid and decreasing the amount of salt, the sensory properties and survival of probiotic bacteria is significantly increased. Probiotic bacteria are survived in all tested samples up to 30 days, but this survival is significantly more than other samples in the treatment containing 3 mgg-1 glutamic acid, 2% salt and at pH 4.9. The highest general acceptance score is belonged to the treatment containing 3 mgg-1 glutamic acid, 2% salt and pH 4.9, which was selected as the best treatment in terms of sensory and nutritional characteristics.
- Developed and rapid extraction of melamine in infant formulae by combined
electromembrane with nanographene oxide reinforced hollow fiber
Abstract: Melamine is a high nitrogen compound used as an adulteration to high protein foods such as infant formulae. There are many different methods for extraction and analysis of melamine which are time-consuming, complex, and need large volumes of organic solvents.A validated method for extraction and cleanup of melamine (MEL) in infant formulae, water, and powdered coffee creamer was developed using a Nanographene oxide (NGO) assisted with electromembrane extraction (NGO/EME) followed by HPLC-UV detection. Supported liquid membrane (SLM) with NGO was used as the adsorbent interface in this study. Synthesized NGO was characterized by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). Effective parameters such as voltage magnitude, SLM solvent, pH of acceptor and donor phases, extraction time, and stirring rate were optimized. The method provided the LOD and LOQ 0.03, and 0.1µg/kg in infant formula, respectively. The accuracy was in the satisfaction recovery rate between 106-109% with RSD 4.83-5.31 for infant formulae as well as the other tested matrices. The developed method based on NGO/EME extraction presents a reliable and rapid analysis for melamine in infant formula.
- Novel adsorbent nanoscale zero-valent iron supported on graphene for the
removal of diazo Direct Red 81 from aqueous solution: Isotherm, kinetics,
and thermodynamic studies
Abstract: In this study, nanoscale zero-valent iron-graphene (nZVI-G) composite was synthesized and applied for the removal of diazo Direct Red 81 from aqueous solution. The prepared nanocomposite was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), and Fourier-transform infrared spectroscopy (FTIR). The particle size was in the range of 20 to 35 nm. The effect of influential experimental variables on dye removal such as contact time, pH, adsorbent dosage, initial dye concentration, and the temperature was investigated. In optimum conditions, including contact time of 10 min, pH = 3, the adsorbent dosage of 0.05 g, and initial dye concentration=10 mg/l, dye removal was achieved 92%. Different adsorption isotherm models (Langmuir and Freundlich) were used and adsorption followed Langmuir isotherm well (R2= 0.9773). The maximum Langmuir adsorption capacity of nZVI-G was obtained 29.07 mg g-1. The pseudo-first-order kinetic model with R2=0.9838 fitted well to the experimental data. The thermodynamic parameters (∆G,∆H,∆S) were calculated and the results revealed that the adsorption of dye was spontaneous and exothermic. The nZVI-G composite was found to be a low-cost potential candidate with high adsorption capability to be applied as an adsorbent for the removal of Direct Red 81 from the aqueous media. Reduction degradation reaction which rapidly produces radicals has a major effect on reaction time. This nanoadsorbent has the ability to adsorb, reduction and degradation of pollutants, so the dye was removed efficiently.
- The evaluation of the anti-Histone deacetylase, antibacterial, antioxidant
and cytotoxic activities of synthetic N,N´-ethylenebis(α
methylsalicylideneiminate) Schiff base derivatives
Abstract: Recently, Schiff base complexes as synthetic antioxidants are widely used instead of natural antioxidants because they are effective and cheaper. In this study, a series of α,ά-Me2-salen, (N,N´-ethylenebis(α methylsalicylideneiminate)) Schiff base derivatives have been investigated toward their anti-histone deacetylase (HDAC), anticancer, antibacterial and antioxidant activities. For anti HDAC studies, AUTODOCK 4.1 and Molecular Dynamics (MD) simulation have been conducted against these combinations. Cytotoxic test, ferric reducing ability of plasma (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) ABTS assays and Agar diffusion method have been applied to investigate anticancer, antioxidant and antibacterial activities, respectively. Based on the results, the best docking was obtained for α,ά-Me2-salen against HDAC. Also, MD calculation results demonstrated that the α,ά-Me2-salen is more effective compound for HDAC inhibiting than SAHA as a known enzyme inhibitor. However, α,ά-Me2-salen and its derivatives didn't display antibacterial activity against any of the microorganisms. Cytotoxic activity analysis toward MCF 7 cell line were apparent that α,ά-Me2-salen and its Ni (II), Co (II), and Cu (II) derivatives manifested high cytotoxic activity with IC50 5, 2, 2 and 3 µg ml−1, respectively. The antioxidant results were revealed excellent radical scavenging activities of all these compounds against DPPH, ABTS and FRAP radicals. The antioxidant activity by DPPH, showed Mn(II) complex (IC50 = 0.13 ± 0.50 mg/ml) was the most active. While, α,ά-Me2-salen (IC50 =0.05±0.003 mg/ml) and its Ni(II) derivative (IC50 =0.049 mg/ml) exhibited the highest ABTS scavenging activity. According to results, all compounds show acceptable anticancer and antioxidant activity and can be used as drug candidates after further investigations.
- Using chemometrics methods for determination of aripiprazole and
quetiapine as antipsychotic drugs in pharmaceutical mixture and biological
fluid by spectrophotometry method based on continuous wavelet transform
and multivariate calibration
Abstract: In this study, two multivariate calibration methods, including partial least squares (PLS) and principal component regression (PCR), as well as continuous wavelet transform (CWT) along with spectrophotometry technique were developed for the simultaneous analysis of Aripiprazole (ARI) and Quetiapine (QTP) in the pharmaceutical formulation and biological fluid. The linear range of ARI and QTP were 1-3 and 2-10 μg mL-1, respectively for the proposed methods. The root mean square error (RMSE) of ARI and QTP related to the test set was obtained 0.014, 0.0758 and 0.194, 0.882 for PLS and PCR methods, respectively. Also, the mean recovery of ARI and QTP was 99.95, 100.04% and 97.38, 98.83% for PLS and PCR models, respectively. Among various families of wavelets in CWT technique, the Coiflet (Coif3) and Symlet (Sym2) families were selected to determine the value of ARI and QTP, respectively. In this method, limit of detection (LOD) and limit of quantification (LOQ) values were found 0.0033, 0.0200 and 0.2764, 0.3486 μg mL-1 for ARI and QTP, respectively. Mean recovery values of ARI and QTP in synthetic mixtures for CWT approach were 96.98%, 98.94%, respectively. One-way analysis of variance (ANOVA) test was applied to compare the results of both mentioned chemometrics models and high-performance liquid chromatography (HPLC) as a reference method. No significant difference was observed between these methods.
- Combined microwave-peanut hull based activated carbon process in the
removal of oxytetracycline (OXT) from aqueous solution
Abstract: Carbon materials are gaining importance in catalytic processes. In this respect, the authors studied the most important characteristics of these materials when employed as catalysts for the removal of pollutants from wastewaters.X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FT-IR) were used to characterized Charcoal Activated (CA) derived from chemical activation of peanut hulls. The key physical characteristics of the solids used in heterogeneous catalysis are the pore volume, the pore distribution, iodine number, oxygen surface groups, and the specific surface area.The combined microwave radiation-CA catalytic activity was assessed through the degradation of Oxytetracycline (OXT) under different irradiation times, initial concentrations, and acidity of the OXT solution. Furthermore, the effect of additional amounts of derived CA on the degradation was assessed.A higher removal rate of OXT contaminant by a combined MW-CA process was a synergic effect and achieved at a low concentration of OXT and pH 3 (which is the pH range of OXT solution). Furthermore, an additional amount of CA increased removal efficiency. These favorable properties make carbon a viable alternative for use as a catalyst with no residual intermediates or secondary pollution.
- Adsorption of Molybdenum from Wastewater by Surface Altered Agricultural
Solid Waste
Abstract: The palm fruit husk, an agricultural solid waste does not adsorb Mo(VI). The intent of this endeavor was to estimate the adsorption capacity of the SAPFH towards Mo (VI) in wastewater. Hence the surface was altered using a surface activating group, cetyl trimethyl ammonium bromide (CTAB). The husk of the palm fruit, whose surface was modified, was subjected to evaluate the extent of extracting molybdenum that is present in aqueous solution. The maximal removal of molybdenum occurs at pH 2.0. The adsorbent dose necessary for the maximum adsorption of MoO42- was lesser for wastewater than for pure aqueous solutions. MoO42- took longer time to attain equilibrium at high concentrations. The stability results were suited with Langmuir, Freundlich and Dubinin-Raduskevich adsorption isotherms models. Dynamic investigation revealed that the uptake obeyed pseudo second order kinetic effigy. The adsorption of adsorbates did not change significantly with increase in temperature. Desorption of Mo (VI) showed that it is possible to retrieve Mo (VI) from the spent adsorbent. The influence of accompanying negative ions such as chloride, phosphate, sulphate and chromate on the Mo (VI) uptake was explored and the anions compete with Mo(VI) ions.
- NaY zeolite and TiO2 impregnated NaY zeolite for the adsorption and
photocatalytic degradation of Methylene blue under Sunlight
Abstract: NaY zeolite was impregnated by TiO2 to prepare novel catalyst for the adsorption and photocatalytic degradation of methylene blue (MB). The samples were characterized by XRD, SEM, EDS and FTIR techniques. The percentage adsorption of MB on NaY reaches 88% and adsorption capacity of 6.55 mg/g under optimized parameters ([MB] = 10 mg/L, pH = 6, S/L = 2 mg/L and T = 25°C). The MB adsorption process follows Langmuir isotherm. The thermodynamic parameters were investigated and showed an endothermic and physical process. The MB adsorption also follows a pseudo second-order kinetic. The photo-degradation of the MB dye was successfully carried out on the TiO2/NaY catalyst under sunlight. The MB photo-degradation also follows a Langmuir-Hinshelwood first-order kinetic.
- Effects of Mg, Ca and K addition on Pt-Sn/γ-Al2O3 for propane
dehydrogenation
Abstract: : In the present study, the applicability of a bimetallic Pt-Sn/Al2O3 in propane dehydrogenation with different promoters, namely, Ca, Mg, incorporation of Mg-K and Ca-K was studied. The catalysts were prepared by the sequential impregnation of γ-alumina support and characterized by TPD, SEM, XRD and UV analysis. The propane conversion and propylene selectivity were evaluated under the representative industrial conditions. The results showed that the Pt-Sn-Mg-K/γ-Al2O3 catalyst had a better performance in terms of propane conversion and propylene selectivity and yield, due to the partially neutralize and synergistic effect of Mg and K (probably by increasing the platinum dispersion and preventing side reaction and coke formation). TPD results also showed the effects of all these promoters (Ca, Mg , Ca-K and Mg-K) on reduction of acidic sites of catalyst, which are favorable sites for cracking reaction and coke formation. In the meantime, Ca is more effective on reducing strong acidic sites, but also Mg is more effective on reducing weak and medium strength acid sites. Therefore, alkaline-earth metals and also using them with potassium could reduce side reaction products and lead to more selective reaction to propylene, and improve catalyst performance compared to industrial catalyst.
- Morpho-structural characterization and electrophoretic deposition of
xonotlite obtained by a hydrothermal method
Abstract: In this research, xonotlite was synthesized by a hydrothermal method in the Si-Ca-Na-H2O system. Detailed structural characterization by using XRD technique revealed that obtained material contains a small quantity of wollastonite (up to 3 %) as impurity. Calcination of the obtained sample at 900 ˚C has resulted in complete transformation of xonotlite to wollastonite which was detected as only crystal phase. Crystallite size and lattice strain of all crystal phases were calculated using Scherrer and Williamson-Hall method. SEM observation of xonotlite morphology revealed tiny needle-like crystals joined together forming dendritic or globular aggregates. Optimal conditions for electrophoretic deposition of xonotlite on 304 type stainless steel have been achieved by appropriate selection of electric field strengths, dispersing medium and dispersants. Stable suspension of material was obtained using isopropanol containing 1 % water as dispersing medium and Ca-nitrate as charging additive. Native layers of xonotlite have a very smooth morphology, while after calcination, the appearance of small cracks in the coating can be observed but the adhesion strength of the coatings to the substrate is improved.
- Synthesis of KBiO3/Nano-Ag3PO4 Composite Photocatalyst and its Application
for Degradation of Organic Pollutant under visible light
Abstract: In this work, a novel composite photocatalyst, KBiO3/nano-Ag3PO4 (K/Ag catalyst), was synthesized, and efficiently degraded methylene blue (MB) under visible light. The various properties of photocatalyst were measured by modern analytical techniques, such as XRD, FT-IR, SEM, XPS, and UV-Vis. We also utilized Density functional theory calculation (DFT) to investigate the photocatalytic degradation mechanism in this reaction process. The multiple characterization findings demonstrated that K/Ag composite catalyst was successfully synthesized using Ag3PO4 and KBiO3, and it displayed excellent absorption for visible light. The photocatalytic results confirmed that K/Ag catalyst greatly promoted the degradation of MB under visible light. The first-order reaction kinetics model could satisfactorily describe the apparent photocatalytic degradation process in this system. In addition, adding electron capture agents to the photocatalytic system highly decreased the degradation efficiencies of target pollutant. Moreover, K/Ag composite catalyst exhibited perfect photocatalyst stability after recycling three times. Through calculating the band structure, Density of States (DOS) and work function, KBiO3 and Ag3PO4 could be considered as n type and p type semiconductor material, respectively. When the composite catalyst was exposed to light, the light-excited electrons would be appeared in both the conduction bands. Furthermore, the transfer trend of electrons and holes made photogenerated electrons concentrate on the conduction band of n type KBiO3, and photogenerated holes concentrate on the valence band of p type Ag3PO4, and thereby greatly improve the photocatalytic efficiency.
- Preparation of expandable polystyrene by multi-stage initiator dosing/
styrene-butadiene-styrene blends with application of artificial neural
networks
Abstract: Expandable Polystyrene (EPS) is one of the most used polymers. Preparation of this polymer by conventional method has some problems which causes the synthesis process to be difficult and quality of the prepared EPS to decrease. In this study, Styrene-Butadiene-Styrene (SBS) has been added to improve some properties of prepared polymer and Multi-stage Initiator Dosing (MID) method has been used to reduce the time of the polymerization which increases the polymer’s production capacity. SBS has been added to EPS in shares of 2%wt, 4%wt and 6%wt. Polydispersity index (PDI) test and the amount of the tension in yield point of the polymer has been checked. The amount of absorbed pentane on the polymer studied. The amount of residual monomer on the polymer has been investigated. All of the studies happened in different conditions like: different percentages of initiator, different number of dosings and different time periods of first stage of the polymerization. Experimental data has been simulated by Multi-Layer Perceptron (MLP) and Radial Basis Function (RBF) methods of Artificial Neural Networks (ANN). The performance of simulation for RBF method was better than MLP method due to having strong scientific foundation and also the ability of filtering noises. The experimental data show that the increase in SBS causes improvement in properties like: elongation at break, better pentane absorption and PDI amount has improved, which show better distribution of molecular weight and decrease in residual monomer in products.
- Surface Fluorinated Microsized-TiO2 for Formulation of Self-Cleaning
Cement
Abstract: The use of nanosized-Titanium dioxide (n-TiO2) for the formulation of self-cleaning cement has the associated drawbacks of nano-toxicity, higher cost and agglomeration in the cementitious material. These drawbacks can be avoided by the replacement of n-TiO2 with microsized-TiO2 (m-TiO2). However, m-TiO2 is less photocatalytically active as compared to n-TiO2 . Therefore, in the present work, surface fluorination of m-TiO2 has been studied to enhance its photocatlytic activity for the formulation of self-cleaning white cement. The commercially available m-TiO2 (average size 40 μm) was surface fluorinated using aqueous solutions of different molar concentrations of NaF (sodium fluoride) such as 10, 50, and 100 mmol dm-3. The surface fluorinated m-TiO2 was analyzed using diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and X-ray diffraction (XRD) analysis to observe the improvement in the physiochemical properties and photocatalytic characteristics. Further, the surface fluorinated m-TiO2 along with calcined dolomite was utilized for the formulation of self-cleaning white cement. The hence prepared self-cleaning cement was cast into cement slabs, which were then characterized by diffuse reflectance spectroscopy (DRS) and energy dispersive spectroscopy (EDS). The self-cleaning ability and photocatalytic activity of the as prepared cement slabs were evaluated through Rhodamine B (RhB) degradation test. It has been found that the use m-TiO2, which was surface fluorinated using 10 mmol dm-3 solution of NaF, remarkably enhanced the photocatalytic performance of the self-cleaning cement.
- Removal of Methyl Orange from aqueous solution using Zeolitic Imidazolate
Framework-11: Adsorption Isotherms, Kinetics and Error analysis.
Abstract: Dyes, which are increasingly harmful to human health and ecology, are an environmental concern and their removal from wastewater is extremely required. It is also important for researchers to find relevant techniques to process these types of pollutants. This study examines the use of the synthesized imidazolate zeolite frameworks-11 (ZIF-11) by stirring method for the methyl orange (MO) dye removal from aqueous solution. The scanning electron microscopy, thermogravimetry, X-ray diffraction, and Fourier transform infrared spectroscopy, were used for the analysis of ZIF-11 particles, which exhibited highly porous, irregular and heterogeneous shapes and variable size. The MO removal was assessed by batch adsorption with ZIF-11 particles as adsorbent, whose efficiency was achieved at pH=8, stirring speed of 600 rpm, for a contact time of 40min and a dosage of 800mg/L of MO solution. The thermodynamic and kinetic analysis of the MO adsorption process was achieved successfully with the pseudo-second order kinetic model as well as Langmuir and Temkin isotherms, indicating the feasibility and spontaneity of the uniform distribution of MO molecules on the active sites of ZIF-11 particles. The calculated maximum adsorption capacity of MO on ZIF-11 particles was 178.57 mg/g, which is indicative of the potential adsorptive properties of the synthesised ZIF-11 for MO dyes.
- Prediction of Optimum Process Parameters for Karanja Biodiesel Production
using Support Vector Machine, Genetic Algorithm and Particle Swarm
Optimization
Abstract: The growing energy demand and depletion of the conventional energy resources presented a need for alternative reliable source of energy that can readily replace the conventional fuels like diesel and petrol. In the current work, biodiesel is synthesized from Karanja oil by using transesterification. The yield is obtained at varying KOH concentrations (1 wt %, 1.5 wt %, 2 wt %), varying molar ratios of methanol:oil (3:1, 4.5:1, 6:1) and varying times (15 min, 30 min, 45 min, 60 min). The optimal conditions from experiment are obtained as temperature of 50° C, reaction time of 45 minutes, methanol-oil ratio of 4.5:1 and catalyst concentration of 1.5 %. The viscosity of biodiesel is found to be between 0.036 - 0.038 stokes. Optimum conditions obtained were compared with the statistics available in literature. The produced biodiesel from Karanja oil conform to the ASTM D6751 standards. The produced biodiesel is characterized using Fourier Transform Infra Red (FTIR) Analysis and Gas Chromatography Mass Spectrometry (GC-MS). Further Artificial Intelligence techniques namely Support Vector Machine, Genetic Algorithm and Particle Swarm Optimization have been used for predicting the optimum conditions of the biodiesel production. The predicted yield with Support Vector Machine is compared with yield obtained from experiments. The SVM accurately predicted the experimental results with the R2 = 0.999. PSO and GA can effectively be used as a tool for predicting the optimum parameters for biodiesel production.
- Solubility Prediction of Etodolac, Lamotrigine, Diazepam and Clonazepamin
in Cosolvent Mixtures Using UNIQUAC Model
Abstract: Etodolac, Lamotrigine, diazepam, and clonazepamine are four important drugs in the pharmaceutical industry that optimizing the solvent concentration in the least amount can reduce the cost and toxicity of these drugs. Due to the lack of thermodynamic modeling based on the activity coefficient equation in previous studies for solubility of Etodolac, Lamotrigine, diazepam, and clonazepamine in aqueous solution, in this study, based on thermodynamic equations and UNIQUAC model, their solubility is optimized with the presence of water and ethanol. Based on the objective function defined, the error rate of the model optimization value was acceptable for each system. The results of this study can be used to better understand the intermolecular reaction of Etodolac, Lamotrigine diazepam, and clonazepamine in the presence of ethanol and water solvents. Also, the importance of the optimization results of this study in order to design a computer program to predict the solubility of these drugs is significant.
- Thermodynamic Modeling the Solubility of CO2 in the Binary and
Three-Component Aqua System of Methyldiethanolamine (MDEA) Using the
N-Wilson-NRF
Abstract: Catching acidic gases, for example, CO2 and H2S from gaseous petrol by alkanolamines are regular in gas cleansing frameworks. In this study, for the first time we use an additional Gibbs argillic model (N_Wilson_NRF) for thermodynamic demonstration of CO2 dissolvability in the double part CO2+MDEA and three part MDEA+H2O+CO2 frameworks. The supposition an altogether atomic framework with no occurrence compound responses and immersed gas stage from the CO2 gas were explored for the point of having a convenient modelling. To decide the dissolvability of CO2 the action coefficient strategy (γ_φ Approach) and the N-Wilson-NRF model were utilized. The result was 1.38 from experimental emerge attain in the two-component water- CO2 modelling. For the three-parts, water-CO2-MDEA framework with the measure of 6.912, the improvement was created.
- Exergy, Economical and Environmental analysis of a natural gas Direct
Chemical Looping Carbon capture and Formic acid-based hydrogen storage
system
Abstract: Chemical looping combustion is one of the novel technologies in energy, which can co-generate hydrogen and power with an efficient carbon capture process to control the system’s emission. This system’s carbon capture process is one of the main processes to achieve the United nations’ environmental goals and other climate change control agencies. This paper aims to study Designing a Natural Gas Direct Chemical Looping Carbon capture and Formic acid Hydrogen storage system for a combined cycle power plant and analyze it with energy, exergy, and environmental factors. The model was implemented on a 500 MW combined cycle power plant unit in Iran, and the results show that if the model is implemented on the plant, overall energy efficiency can be increased by 33%. Furthermore, according to the references, the carbon emissions decreased more than 93%, which is an achievable target using the Chemical looping combustion.
- Heatlines Analysis of Natural Convection in an Enclosure Divided by
Sinusoidal Porous Layer and Filled by Cu-Water Nanofluid with Magnetic
Field Effect
Abstract: A numerical study is executed to analyze the steady state heatlines visualization, fluid flow and heat transfer inside a square enclosure with a present of magnetic field. The enclosure is divided into three layers, right and left layers filled with (Cu-Water) nanofluid while the center layer is sinusoidal porous filled with the same nanofluid. Constant hot and cold temperature is applied to right and left walls, respectively, top and bottom walls are adiabatic. Galerkin finite element approach based on weak formulation is applied to solve the governing equations. The parameters studied are number of undulation (N=1, 2 and 3), Rayleigh number (103≤Ra≤106), Darcy number (10-5≤Da≤10-1), Hartmann number (0≤Ha≤100) and volume fraction (0≤φ≤0.06). Three cases were provided depending on the number of undulation of porous medium layer. The results obtained that the absolute value of the maximum stream function decreases with the increase of Hartmann number and decrease of Darcy number for all the three cases of the wavy porous layer. Heatlines and isothermalines increase as the Darcy number is increased. The average Nusselt number growths by increasing the Rayleigh number and decreasing the Hartmann number. The enhancement of heat transfer occurred for case (2) as the Darcy number increased at a constant Ra=105, Ha=40. Also, It can be concluded that there was an excellent agreement between this study and those of Hamida and Charrada, by approximately maximum absolute error of 2.062%.
- Energy, Exergy and economic analyses of a combined heat and power
generation systems with a gas turbine and a horizontal axis wind turbine
Abstract: Using the Combined Heat and Power (CHP) systems are known as one of the most effective ways to raise the power coefficient and reduce fuel consumption and operational costs. In this study, a CHP system with the prime movers of a gas turbine and a horizontal axis wind turbine under the strategy of providing electric charge has been investigated based on the first and second laws of thermodynamics. This study aims to evaluate the effect of a wind turbine on the CHP system. The results show that the proposed CHP system has significant advantages compared to the CHP system working without the wind turbine. The best operating condition for the wind turbine is at the wind speed of 12 m/s, the pitch angle of 5ο and the tip speed ratio of 3. Moreover, the effects of the wind speed and tip speed ratio on the exergy efficiency of the total system become considerable when the gas turbine works at the high-pressure ratios (more than 10) and the combustion chamber temperature below 1250οc. Also, it is shown this integrated system can reduce operational costs and fuel consumption by 55 % and 60%, respectively. Finally, regarding the interest rate, the payback period will be equal to 5.4 years.
- Energy, exergy, and exergoeconomic (3E) analysis of gas liquefaction and
gas associated liquids recovery co-process based on the mixed fluid
cascade refrigeration systems
Abstract: In this paper, energy, exergy, and exergoeconomic analysis is performed on the recent trend of joint production of liquefied natural gas and natural gas liquids based on Mixed fluid cascade most important refrigeration systems. The proposed process is first simulated and exergticly analyzed, and finally, an economic model is used to analyze the exergoeconomic performance. The results include the cost of exergy destruction, exergoeconomic factors, and exergy efficiency. The exergy analysis results show that the proposed process’s exergy efficiency is about 53.84%, and the destruction rate is 42618 kW with LNG and NGL production rates of 69.00 kg/s and 27.42 kg/s, respectively. Also, results show that the maximum exergoeconomic factor, which is 69.53%, is related to the second compressor in the liquefaction cycle. The lowest exergoeconomic factor, which is 0.67%, is related to the fourth heat exchanger in the liquefaction cycle. In this process, the distillation tower has the highest relative cost variation (100.81), and the first air cooler in the liquefaction cycle has the smallest relative cost difference (1.08). One of the most costly economic factors is the cost of exergy destruction rates. The second heat exchanger has the exergy destruction cost (768.93 $/GJ), and the first air cooler in the liquefaction cycle has the lowest exergy destruction cost (19.38 $/GJ).
- Computational Fluid Dynamics Modelling and Analysis of Heat Transfer in
Multichannel Dimple Plate Heat Exchanger
Abstract: In the present study, Computational Fluid Dynamics is used for the heat transfer studies in the dimple, and flat plate heat exchangers. By employing water as a working medium (fluid), the same and different flow analyses were numerically studied. SOLID WORKS 2018 software was used for the study. The study primarily investigated the effect of the flow rate of hot fluid on the overall heat transfer coefficient. The study also analyzed the influence of hot fluid’s Reynolds number on cold fluid’s Nusselt number. It was observed that an increase in the mass flow rate of the hot fluid from 0.016 to 0.067 kgs-1 resulted in an increase in the heat transfer coefficient from 65 to 298 Wm-2K-1 for dimple plate heat exchanger (DPHE). Meanwhile, an increase in the Reynolds number of the hot fluid (from 200 to 1000), induced an increase in the Nusselt number of the cold fluid from 1.9 to 8.7 for DPHE. A correlation was developed to calculate the Nusselt number for the same flow analysis of the flat plate heat exchanger (FPHE). The study also compared the performance of the DPHE with that of the FPHE. The results of the same flow analysis indicated that the DPHE exhibited a Nusselt number value 39% greater than the FPHE at the highest mass flow rate of 0.067 kgs-1, while in different flow analysis, the DPHE demonstrated a Nusselt number value 41% greater than the FPHE at the highest mass flow rate of 0.067 kgs-1.
- An experimental investigation on drag reduction by a combination of
polymer, Laurel soap and palm fiber through circulated Newtonian liquid
Abstract: Flowability and reduced pressure are some of the economic values in pipeline transportation. In this study, we investigated the functionality of self-made drag coefficients composed of a combination of large molecular weight polymer, Laurel soap, and date palm fiber which were induced into a circulated piping system under turbulent water flow. The proposed combination formulas are proved to be a new cost-effective drag reduction approach. The efficiency of using a mixture of polymer, palm fiber, and soap on the drag reduction was thoroughly evaluated via investigating several case studies. Using pure polyelectrolyte showed that at the highest polymer concentration (50 ppm), the percentage of drag reduction reaches 50% in 10.3 mm pipe diameter and 70% drag reduction in 13.5 mm pipe diameter at a flow of low Reynolds number counted 17166.7. Upon applying a mixture of polyelectrolyte composed of (50 ppm) and fiber in the range (30-60 ppm), a drag reduction of 63% in 10.3 mm pipe diameter and 76% in 13.5 mm pipe diameter were achieved, respectively. Upon examining a mixture composed of polyelectrolyte (50 ppm) and soap in a range (50-150 ppm), the results showed that the highest drag reduction was achieved at a low concentration of soap and a bulk flow at a low Reynolds number. The aforementioned performance results were exemplified attaining drag reductions of 70% in 10.3 mm pipe diameter and 96% in 13.5 mm pipe diameter, respectively. This is accomplished through optimizing the applied mixture formulas. The estimated drag reductions were shown higher when applying the polymer mixture compared to that of pure polymer. However, a slight decrease in the attained drag reductions when using polymer-soap was observed and attributed to the hindrance from the palm fiber, which ultimately reduces the chance for all soap particles to reach the stagnant wall layer
- Prediction of product distribution in the delayed coking of Iranian vacuum
residue
Abstract: The delayed Coker process as an upgrading process has main impact on the productivity of the Refinery Complexes. To determine the impact of different operating conditions on the product yield distribution of the delayed coking process, several experiments were designed and conducted in a prefabricated pilot plant. The experiments were conducted on different Iranian vacuum residues at temperatures ranging from 420°C to 480°C and at atmospheric pressure. Reaction times were within the range of 5-120 minutes. A four lumps kinetic model has been developed based on the experimental results. The lumps—which included Volatile products, coke, feed, and an intermediate phase between coke and feed—were defined to precisely monitor the yield distribution of products throughout the reaction time. The feedstocks utilized were three different vacuum residues and their blends. The mixtures were produced by using different mixing ratios of the three vacuum residues. The Statistical analysis shows that this model has R-squared, RMSE, SSE, and MRE equal to 0.99, 0.022, 0.08, and 3.537%, respectively. This shows that the developed model is sufficiently accurate. The experimental and modeling results in this research reveal that by increasing the temperature, the yield of coke and gas is abated. However, the yield of the distillate is escalated. This investigation illustrates that the production of an intermediate reaction has the highest amount of activation energy in comparison with the other reactions. Also, the results indicate that the production reaction rate of coke has the highest amount in comparison with other reactions.
- Investigation of antibacterial and cytotoxicity effect of green
synthesized TiO2 nanocomposites, an experimental and theoretical study
Abstract: Protecting the hair, skin, or products of itself are utilized by sunscreen filter which was frequently blocked hazardous UV-Vis radiation. . Considering its photoprotective impact on the skin facing the radiation of ultraviolet and visible, TiO2 is a common and cost-efficient photocatalytic structures utilized in sunscreens. In this research, the continual process was done to optimize the green synthesized of TiO2 nanoparticles and nanocomposites through a new, easy, cost-efficient and quick approach to make nanostructures utilizing a sonochemistry method. SiO2, Al2O3, ZnO and MnO were utilized to compose with green synthesized TiO2 nanoparticles for this purpose. The samples were recognized by XRD, FT-IR, DLS and SEM. Also, the cytotoxicity and antibacterial activity were assessed. DFT computation was performed to identify the connected energy and band gap energy of nanocomposites by B3LYP/Lan2DZ quantum approach. TiO2/Al2O3 showed a lower size and the lowest agglomeration than synthesized TiO2 and other nanocomposites. Furthermore, all samples indicated strong antibacterial activity against investigated bacteria due to cell death caused by membrane permeability increase and bacterial wall integrity disruption. Nanostructures has cytotoxicity with low level on A172 cells. The only exception is TiO2/ZnO which indicated a potent index of cytotoxicity on the cancerous cell lines as demonstrated by low IC50 value of 50 ppm. Relative energy and band gap of nanocomposites indicated that TiO2/Al2O3 has the best stability in chemical and biochemical medium among other nanocomposites. These green synthesized TiO2/Al2O3 nanostructures may have promising application in nanoformulation to combat bacterial infections in the future.
- Bio-based Surface Modification of Wool Fibers by Chitosan-graphene Quantum
Dots Nanocomposites
Abstract: Wool proteins have various chemical active groups which could create chemical reactions and bonds with functional groups existent in different substances. Hence, to have special features and competencies, one could perform surface modification of wool fibers using various chemical composites. This paper aims mainly to achieve surface modification of wool fibers by chitosan-nitrogen doped graphene quantum dots (Ch-NGQDs) as bio-based nanocomposites, and to investigate its consequent effects on the various properties of wool fibers such as color fastness, colorimetric parameters and antibacterial activities. To do this, first, Ch-NGQDs nanocomposites were synthesized including certain weight percentages. Then, wool fibers were modified by prepared nanocomposites. In order to characterize and confirm the synthesis of NGQDs and Ch-NGQDs nanocomposites, FT-IR, XRD, HR-TEM, UV-visible and photoluminescence spectrometry were applied. Subsequently, surface modification of wool fibers by Ch-NGQDs nanocomposites was studied using FESEM spectrometry, analysis of fastness properties, colorimetric parameters and Mueller-Hinton broth antibacterial test. Findings showed that surface modification of wool fibers by Ch-NGQDs nanocomposites led to partial improvement in their color fastness and colorimetric parameters. Additionally, surface modification of wool fibers resulted in elimination of Staphylococcus aureus bacteria.
- Synthesis of rare earth (Dy and Pr) metal impreganated asparagine
functionalized CoFe2O4 nanocomposite: Two novel, efficient and
magnetically-recoverable catalysts for the reduction of 4-nitrophenol
Abstract: In recent times biomolecules engineered magnetically isolable nanoparticles have garnered significant attention in nanocatalysis arena due to their outstanding features. Doping of rare earth metals over them brings further novelty in their properties. In this current work we describe the successful synthesis of rare earth lanthanide (M = Pr, Dy) impregnated asparagine adorned CoFe2O4 as two novel magnetically isolable nanocomposite catalyst following post-functionalization approach. The as synthesized materials were characterized using physicochemical techniques like FT-IR, SEM, EDX, elemental mapping and ICP-OES analyses. Subsequently, catalytic efficiency of the materials were investigated in the reduction of 4-Nitrophenol (4-NP), a well-known carcinogenic contaminants of water. Progress of the reaction and its kinetics were monitored over UV-Vis spectroscopy. Among the two variant, Dy anchored catalyst was found to be more efficient than the Pr which led the reaction to completion in just 8 min. Kinetically also Dy catalyst exhibited higher rate constants. This is the first report of Pr and Dy anchored heterogeneous catalyst in the reduction of 4-NP. The current methodology is advantageous in terms of cleanliness, simple procedure, excellent yields in short reaction time, easy magnetic retrieval and reusability of catalysts following several runs without significant change in catalytic activity.
- MODIFICATION OF NATURAL ZEOLITE FOR ANTICORROSIVE PAINT PREPARATION
Abstract: Metal surface coating occupies an important place in industry. The most important external factor on metal surfaces is corrosion. Corrosion is a natural process that occurs because of chemical reaction between the metal surfaces and the medium. It causes degradation of metals. There are three methods that used for the prevent corrosion. These methods are cathodic protection, anodic protection, and barrier coatings. In this study, it was aimed to develop environmentally friendly corrosion resistant paint for the barrier coatings, by using zeolite material which has natural characteristic of corrosion resistant. In other words, it was aimed to gain the anticorrosive effect to the production of corrosion resistant paint by adding modified natural zeolite in paint. Micro scale zeolite was modified by using lanthanum (III) nitrate, zinc acetate and magnesium chloride solutions. The best results were obtained with a zeolite size of 0.8869 μm and using a 60% zeolite / solution volume ratio. It can be said from the results of the experiments that; thin zeolite film applications are very successful for corrosion resistance paint production. Modified natural zeolite coatings show very good ability to protect surfaces from corrosion. Results of these procedures are positive and promising. The best result is obtained by zeolite with size reduction and 60% zeolite/solution by volume ratio. The amount of zinc phosphate was greatly reduced. High and low content of zinc phosphates have almost the same anticorrosive effect with zeolite modified paint formulations. As a result, cation-exchanged zeolites can be considered as a safe and efficient alternative to traditional hazardous pigments in protecting steel surfaces.
- Synthesis, Characterization and Antimicrobial Activity of Some New
Tetrazole Derivatives from Hydrazones
Abstract: In this investigation, a combination of Z1-Z5 hydrazone compounds is obtained from the reaction between 4-methylbenzohydrazide and aryl-aldehydes. Subsequent unique synthetic approach to the preparation of di-substituted tetrazoles T6-T10 was achieved through a 1,3- dipolar cycloaddition of sodium azide and prepared hydrazone compounds in ethyl alcohol. Results have been verified by Fourier-transform infrared spectroscopy (FTIR), 1H and 13C-nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry. The activity of anti-microbial screening has shown that (Z1–Z6 and T10) presented antifungal activity. The other tested Z2 compound was found to exhibit good antibacterial activity, while the other tested compounds revealed low antibacterial activity.
- Dibutyltin(IV) complex of 2-[(E)-(4-hydroxy-3-{(E)-[(quinolin-2-yl)imino]
methyl} phenyl) diazenyl]benzoic acid: Synthesis, spectroscopy and in
vitro antifungal activity
Abstract: ABSTRACT: Dibutyltin(IV) complex of 2-[(E)-(4-hydroxy-3-{(E)-[(quinolin-2-yl)imino] methyl} phenyl) diazenyl]benzoic acid was synthesized by refluxing 2-[(E)-(4-hydroxy-3-{(E)-[(quinolin-2- yl) imino] methyl} phenyl) diazenyl]benzoic acid with dibutyltin(IV) oxide in hot toluene. The complex was characterized by elemental analysis in combination with UV-visible, IR, 1H, 13C, 119Sn NMR spectroscopy and Mass spectrometry technique. The carboxylate ligand acts as chelating bidentate mode of coordination with the tin atom in the complex. The complex exhibited cyclic dimeric structure in the solution state where the tin centers adopt 6- coordinate octahedral geometry. The in vitro antifungal property of the ligand and the complex was observed and compared with reference drug, Amphotericin-B.
- Regeneration study on active components supplement of waste V2O5-WO3/TiO2
SCR catalyst
Abstract: The waste selective catalytic reduction (SCR) catalysts were regenerated by active components supplement on the basis of alkali/acid washing treatment. Through orthogonal design, the regenerated SCR catalyst restored the denitration activity of 98.36% at optimal regeneration parameters of 6% WO3 loaded after 1.2% V2O5 loaded and then calcined at 500 oC. The catalysts were characterized by XRD and H2-TPR techniques. The XRD patterns and the FT-IR spectrogram showed that the supplemented V2O5 and WO3 were dispersed uniformly in amorphous state on the surface of TiO2 support which remained as anatase phase. The H2-TPR characterization reported that V2O5 significantly affected on the low-temperature activity while WO3 mainly affected the high-temperature activity, the loading sequence of V2O5 before WO3 not only enhanced the interaction between V2O5 and TiO2 but also facilitated the enrichment of WO3 on TiO2 surface.
- Methane dehydroaromatization over Mo and W catalysts supported on ZSM-5
Abstract: Methane aromatization reaction to produce benzene using tungsten and molybdenum catalysts supported on ZSM-5 was investigated at 800 ºC. Catalysts were prepared by impregnation of tungsten and molybdenum salts on ZSM-5 zeolite with various metal loadings in the range of 2-10 wt. %. In order to obtain the catalytic structures before and after the reaction, catalysts were characterized by XRD and FTIR analysis. It was indicated from reactor tests that increase of metal loading on the catalyst surface leads to increase methane conversion (1.1% and 3.2% for 2W/ZSM-5 and 6 W/ZSM-5, and 2.4% and 4.8% for 2W/ZSM-5 and 6 W/ZSM-5, respectively, at time of stream equals 120 min). It was also concluded that Mo catalysts show higher activity and stability than W (methane conversion of 3.2 and 9 % using 10Mo/ ZSM-5 and 10 W/ZSM-5 catalysts respectively, at time of stream equals 100 min), and increase of Mo loading leads to enhancement of catalytic activity and methane conversion, which indicate initial activation of methane is occurred on metal sites of catalysts. This activation leads to occur the later reactions and production of final benzene. These conditions confirm the two-factor mechanism which include two stages: i) hemolysis break of C-H bond and CH3 radical formation and then ethylene formation, and ii) cyclization of ethylene species in the presence of acidic sites within the zeolite channels. Investigations on mesoporous HMS support showed no aromatic production, which show increase of support channel diameter leads to reduce the possibility of ring formation.
- Alternative Approach of Gold Extraction using Modified Borax
Abstract: The extraction of gold in many part of the world is left in the hands of artisanal local miners who do this with the use of mercury which is considered to be a very hazardous chemical to human and the biophysical environment. This research investigated the use of borax as a replacement for mercury in extraction of gold from its ore. The sample used for the study was collected from Chanchaga mining site in Niger State. Calcination of the sulphide ore was done at a temperature of 600 oC in order to oxidize the sulphur content of the ore. The Borax in its modified form was used as a metal flux in the extraction process and this was optimized through Box-Behnken experimental design method using Design Expert 7.0 software. The effect of temperature, mole ratio of heavy mineral concentrate to borax, and time were studied at 800 – 1000 oC, 0.8 – 3.5 and 15-30 min respectively. Sieve, X-Ray Fluorescence (XRF), and carat analysis of the samples were carried out. The percentage yield of gold extract was 70.2 % at 900 oC, 30 min and 0.8 mole ratio of heavy mineral concentrate to modified borax. The sieve analysis shows that visible gold liberation was achieved between 0.3 and 0.15 mm, the X-Ray Fluorescence showed 88.7 % extract gold purity with 22 carat. This method can be a replacement for the current toxic method of gold extraction using mercury.
- Some chemical properties and biological activity of an endemic plant
Tripleurospermum callosum as a case study
Abstract: T. callosum an endemic plant, used in this study, efficiently inhibited enzymes, with IC50 values of 28.87 mg/mL, 15.75 mg/mL, 36.47 mg/mL, and 60.0 mg/mL, for AChE, BChE, α-Gly, and GST respectively. The antioxidant activities of the water and methanol extracts of the T. callosum were investigated using four in vitro techniques. The antioxidant activity of water extract against ABTS radical was very strong as in the case of standards. Quinic acid 16.675 (mg/g) was detected as the most intensive phenolic compound in T. callosum by using the advanced LC-MS/MS technique. The computational screening of the studied ligands revealed the docking energies in the range of -3.414 to -8.394 kcal/mol for four enzymes. Among the six phenolics, two phenolics (apigenin, and luteolin) showed the binding energies of < -8 kcal/mol with AChE. In conclusion, the biological activities of the plant might be due to its rich chemical composition.
- Modeling and Numerical Solution of the Fate of Multicomponent Substrate in
Porous Media
Abstract: A mathematical model was proposed to appropriately describe the fate of multicomponent substrates in porous media especially soil. The model utilised appropriate biodegradation kinetic expressions that better describe the consumption or degradation rate of the substrate. The Equation, with the second and third type boundary conditions in non-dimensionalised form was solved using the Finite Volume method and simulated in the Matlab environment. An experiment, using a 5 cm (inside diameter) x 60 cm (height) glass column packed with severally autoclaved soil spiked with 2 % substrate (a mixture of hexadecane, heneicosane, 1-methylnaphthalene, 2- methylnaphthalene and 1, 3-dimethylnapthalene) and a consortium of organisms (Providential rettgeri, Streptococcus salivarius, Trichoderma harzianum, Aspergillus flavipes, and Candida famata) was set up to validate the model. The result showed that the model describes the fate of each component within the multicomponent substrate. It also indicates that both Peclet and Thiele numbers affect the biodegradation of the substrate. It was observed that small Peclet number should be allowed for effective biodegradation of the substrate. The model was validated with data obtained for an experiment where a mixture of hydrocarbons was degraded with a mixed culture of microorganisms. The results of the experiment were well described by the model indicating that the model can be used to predict compositions of components of a mixture during biodegradation.
- Solvent Extraction of Copper Ions from Wastewater using Reverse Micelles:
Experimental and Optimization
Abstract: In this study, the optimum conditions for different process parameters were determined for solvent extraction of copper ions from wastewater using reverse micelles. The process parameters viz. copper ion concentration, sodium bis-2-ethyl hexyl sulphosuccinate (AOT) concentration, solution pH, organic to aqueous phase volume ratio, and NaCl concentration were taken into consideration in response surface methodology, ranging from 30-150 mg/l, 0.04-0.2 [M], 3-11, 0.2-1.0, 0-4 g/100 ml respectively and their effect on percentage removal of copper ions were studied. A regression model was developed by conducting response surface methodology for the analysis of percentage removal of copper ions from wastewater. As many as fifty four experiments were procured from the design of experiments for the percentage removal of copper ions. The developed model was employed to optimize the process parameters being considered to maximize the response. The optimum conditions were found to be 30 mg/l copper ion concentration, 0.20 [M] AOT concentration, 3.12 pH, 0.57 organic to aqueous phase volume ratio, and 0.134 g/100 ml NaCl concentration. The obtained model was validated with experimental data and found to be best fitted within the tolerance limit. The effect of cross-interaction among the process parameters on the percentage removal of copper ions were also investigated. In this study, the copper ion concentration was analyzed by Atomic absorption spectroscopy (AAS).
- Kinetics, equilibrium, and thermodynamic studies on Fe3+ removal from
aqueous solutions by chemically modified brown algae
Abstract: Sargassum Vulgare was used as an effective biosorbent for the removal of Fe3+ from aqueous solutions. Results for batch operation are presented for biosorption onto algal biomass, raw and modified with HNO3, HCl, NaCl and CaCl2. NaCl was selected as the best modifier of algae surface for the improvement of the sorption capacity. Optimum biosorption conditions were determined as a function of contact time, biomass dosage, initial metal concentration, and temperature. The Langmuir isotherm yield high regression values for a maximum monolayer sorption capacity of the modified biomass of 30.52 mg g-1 at optimum conditions (pH = 2, dose = 5 g L-1, t = 120 min, and T= 298 K). This represents an increase of more than 50 % with respect to the raw algae. The kinetics of sorption followed the pseudo-first-order rate equations, and is fast enough to prove the technique feasible. The thermodynamic parameters showed that the adsorption of Fe3+ using algal biomass was feasible, spontaneous, and exothermic. Modified algae could be regenerated once using 0.001M EDTA solution, a recovery of 90% of Fe3+ was obtained. Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to characterize the surface of modified algae.
- Adsorption of Methylene blue (MB) dye Using NiO-SiO2NPs Synthesized from
Aqueous Solutions: Optimization, kinetic and equilibrium studies
Abstract: The applicability of the synthesized NiO-SiO2NPs as a novel adsorbent for eliminating Methylene Blue (MB) dye from aqueous media was investigated. Various techniques including BET, FT-IR, XRD, SEM and EDS were used to characterize this novel adsorbent. The investigation showed the applicability of NiO-SiO2NPs as an available, suitable and low-cost adsorbent for proper removing of MB dye from aqueous media. The effect of pH, adsorbent dosage (dose), initial MB dye concentration (C0) contact time (tc) and temperature (T) on the removal percentage (Ad%) of MB dye onto NiO-SiO2NPs was studied and the optimum value of each factor was determined (pH=7, dose=0.1g, C0=30 mg/L, tc=15 min and T=298.0 K). The experimental equilibrium data was fitted to the conventional isotherm models and accordingly Langmuir isotherm has good applicability for the explanation of experimental data with maximum adsorption capacity of the MB dye for SiO2 and NiO-SiO2NPs were roughly 117.0 and 140.0 mg/g respectively. Kinetics experiments were performed to investigate the adsorption kinetics, the pseudo-second-order kinetics coincided quite with the kinetic results. The thermodynamic behavior of the adsorption process was studied by considering the effect of temperature on the adsorption capacity, where the results showed that the process is spontaneous (∆G, Ad 0<0) at used temperature range and exothermic (∆H, Ad 0<0) with ∆S, Ad 0<0. Based on the magnitude of ∆H, Ad 0<0, it was concluded that the studied adsorption process is a physisorption one.
- Applying Neural Network Model for Adsorption Methyl Paraben (MP) dye Using
Ricinus Communis-capeed Fe3O4 NPs Synthesized from Aqueous Solution.
Abstract: ABSTRACT: The applicability of the synthesized Ricinus Communis-capeed Fe3O4NPs as a novel adsorbent for eliminating Methyl Paraben (MP) from aqueous media was investigated. Various techniques including Brunauer Emmett Teller theory (BET), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray (EDX) were used to characterize this novel adsorbent. The maximum adsorption efficiency of (MP) dye onto Ricinus Communis-capeed Fe3O4 NPs was 98.6% at optimum pH value of 7.0, adsorbent dosage of 0.01 g, (MP) dye concentration of 15 mg/L, and contact time of 12 min were considered as the ideal values for (MP) dye. The adsorption data fitted well with the Langmuir isotherm model with correlation coefficient (R2 > 0.97), whereas the adsorption kinetics followed the pseudo-second-order kinetics. The use of artificial neural network model in predicting data with Levenberg–Marquardt algorithm, purlin or a linear transfer function at output layer, and training was helpful. ANN model as a tool (mean square error) MSEANN = 0.0034, MSEFL = 0.023 and MSEANFIS = 0.0020 for removal of the (MP) dye onto Ricinus Communis-capeed Fe3O4 NPs synthesis. Thermodynamic parameters of free energy (ΔG0), enthalpy (ΔH0) and entropy (ΔS0) of adsorption were determined using isotherms. ∆H0=59.58 kJ/mol, ∆G0= -2.8324 kJ/mol and ∆S0=221.15 kJ/mol. K. The value of (ΔGo, ΔHo and ΔSo) confirmed the sorption process was endothermic reflects the affinity of Ricinus Communis-capeed Fe3O4NPs for removing (MP) dye onto Ricinus Communis-capeed Fe3O4NPs process requires heat. The maximum monolayer capacity (qmax) was observed to be 195.0 mg/g for (MP) dye at desired conditions.
- Optimization and Removal Efficiency of Basic Textile Dyestuffs with Using
Perfluorosulfonic Acid-Based Polymer
Abstract: The removal of basic dyestuffs (Basic Red 46 and Basic Blue 41) from synthetic dye solutions was examined via using perfluorosulfonic acid-based polymer for the first time in the present study. The effects of four different variables, such as pHs (3.0, 5.0, 7.0, 9.0 and 11.0), temperature (25 °C, 35 °C, 45 °C, 55 °C and 65 °C), initial dyestuffs concentration (20, 40, 60, 80 and 100 mg L-1) and treatment time (20, 40, 60, 80 and 100 min.) on the removal performance were investigated. The optimum conditions were determined for R46 as pH: 6.5; temperature: 54.1 °C; concentration: 97.4 mg L-1; time: 60.8 min. and for B41 as pH: 7.5; temperature: 54.6 °C; concentration: 67.1 mg L-1; time: 69.5 min. by using Response Surface Methodology. Removal performance values for R46 and B41 were determined respectively 99.9% and 99.5% at the optimum conditions. Also, perfluorosulfonic acid-based polymer was able to regenerate up to 20 cycles without significant performance change for the dyestuff removal process.
- Reduction in Noise Pollution of a Gas Power Plant under Construction Using
Synthesis of Copper and Nickel Alloy Foam in a Simulated Setting
Abstract: Noise pollution is one of the challenges of installing equipment and developing industries. The control of noise generated by small power plants is a necessity for its use development. Designing the synthesis of copper and nickel alloy foam and using this foam to reduce noise pollution in the exhaust is one of the effective methods to control and reduce noise pollution from power plants. The purpose of this study was to synthesize copper and nickel alloy foam and compare the effect of results of spl changes in software ANSYS for three ductless, ideal wall and multilayer wall modes at different frequencies. In this regard, the adjunct duct is modeled as 3D by software ANSYS, and the output sound intensity of the duct in the acoustic setting is analyzed in several different modes. The results show that three different modes in the exhaust output indicate that the multilayer wall at most frequencies reduces the sound pressure level relative to the ductless or ideal wall modes.
- Optimization production conditions on the amount of nitrogen compounds in
Iranian fish sauce (Mahyaveh)
Abstract: Mahyaveh is a traditional Iranian fish sauce produced by fermentation and hydrolysis. Fish sauce is considered a rich source of protein and contains essential amino acids. The type of fish, salt concentration and fermentation time are affective on the nitrogen properties of Iranian fish sauce and its quality. Therefore, the aim of this research is to study the type of fish, salt concentration and fermentation time on the nitrogen properties and increase the bioactive compounds of Iranian fish sauce (Mahyaveh). The results are shown that the increase of time (30 to 120 days), and salt concentration (35 to 15%) has a significant effect (P≤0.05) on the increase of nitrogen properties, fermentation time (30 to 120 days) and salt concentration (15 to 35%), but decrease on trimethylamine. Multiple optimization to achieve the maximum nitrogen properties and minimum trimethylamine in the Mahyaveh with 95.56% desirability is obtained at 120 days of fermentation, salt concentration of 18.73% with use of sardine. By optimizing the conditions of producing, Mahyaveh can be produced with the nutritional value and higher quality.
- IMPROVISATION OF COMBUSTION BEHAVIOUR OF JOJOBA OIL DIESEL BLEND FUELLED
DI DIESEL ENGINE BY ENGINE MODIFICATIONS SUCH AS MOP AND TBC
Abstract: To reduce the importance of fossil fuels, the identification of biofuels plays a vital role. The plant oil chosen for this study is novel plant oil named Jojoba oil (the botanical name is Simmondsia Chinensis). To utilise this type of oil in higher proportion with diesel, engine modifications were carried. The engine modifications include optimising salient operating parameters with Thermal Barrier Coating (TBC). Taguchi and Gray relational methods were used for finding the optimised values of salient operating parameters like injection pressure, compression ratio, injection timing and intake air temperature as 275 bar, 19.5 CR, 27.5 bTDC and 65˚C, respectively [1]. This has helped to combust the higher blends of jojoba oil, namely 60J, 70J and 80J, without adverse performance and emission characteristics. The fundamental aim of coating Aluminium oxide, Molybdenum and Titanium oxide (40%, 30% and 30%) on the inner surface of the piston crown and the cylinder head is to retain heat and thereby achieve higher thermal efficiency. Combustion, performance and emission analysis were done and found that 60% by volume of jojoba oil can be applied in a TBC engine which offers 11.5% higher BTE, 74.3% lower CO, 31.2% lower HC, 8.6% higher NOx and 25.9% lower smoke than 70% and 80% by volume of jojoba oil.
- STUDY OF HEAT EXCHANGER NETWORK CLEANING SCHEDULE DESIGN WITH HEURISTIC
SCENARIO ANALYSIS
Abstract: The crude oil refinery heat exchanger network (HEN) cleaning schedule is critical to maximize the energy recovery and simultaneously maintain the HEN performance. In reality, the HEN configuration consists of multiple heat exchanger units with different sizes, fouling rates, and initial efficiencies. The plant availability and the HEN efficiency may decrease to a certain level after a period of operation due to fouling and heat exchangers taken offline for cleaning. Therefore, cleaning and bypass procedure is deemed necessary. In this study, the heat exchanger performance represented by the overall heat transfer coefficient is evaluated based on a proposed heuristics algorithm for seeking the optimum cleaning schedule while incorporating rigorous cleaning rules. Four heuristic values for HEN cleaning schedule scenarios are proposed to evaluate the overall performance of the HEN. The additional heat duty on the process heater due to cleaning operation and the total annual cost are considered in a crude oil refinery HEN that consists of 11 heat exchanger units. The cleaning frequency of the heat exchanger is found to have a significant effect on HEN performance. The results from the scenario analysis suggest that there is a proper cleaning schedule for optimum operation of a crude oil refinery HEN. It is also indicated that the design of the cleaning schedule depends on fouling resistance and the capacity of related heat exchangers.
- Numerical study of natural convection of nanofluids in an inclined flat
bottom flask using finite-volume approach.
Abstract: In this work, we study numerically the natural convection of nanofluids (NF) in an inclined flat bottom flask; it is one of laboratory flasks used in organic chemistry synthesis. The main reason of this study is to enhance the thermal properties of the reaction medium inside the flat bottom flask and to ameliorate the rate of chemical reactions using nanofluids. The flat bottom wall is maintained at a constant high temperature Th. While the top, left and right walls of the cavity are maintained at a low temperature TL. The NF comprises Cu and Al2O3 nanoparticles (NP) suspended in pure water. The governing equations are solved numerically using the finite-volume approach and formulated using the Boussinesq approximation. In this simulation we examined the effects of the NP volume fraction (φ) from 0% to 5%, the Rayleigh number from 103 to 106, the various inclination angles of enclosure (γ=0°,5°,10°, 15°) and the NF type (Cu and Al2O3) on the flow streamlines, isotherm distribution and Nusselt number. The obtained results show that the addition of Cu and Al2O3 NP increases the mean Nusselt number which enhances the heat transfer in the flat bottom flask and causes significant changes in the flow pattern. In addition, the mean Nusselt number is increase with increasing the Rayleigh number and the volume fraction and the best results have obtained from the Cu nanofluide. Also, as the inclination angle increases the mean Nusselt number decreases and the highest value of Nusselt number was obtained for a vertical enclosure (γ=0°). The obtained streamlines are mostly symmetric and their values are generally increase by increasing the Rayleigh number and volume fractions of NPs. Besides, the obtained isotherms are generally follow the geometry of the flat bottom flask.
- Mass Transfer, Energy-Exergy Analysis, and Mathematical Modeling of Chili
Pepper during Drying
Abstract: There are no literature data on the effects of air velocity and relative humidity on moisture diffusivity, mass transfer coefficient, and energy-exergy analysis of chili pepper during cabinet-tray hot-air drying. This study tends to address this gap by presenting comprehensive drying kinetic, energy, and exergy analyses of a cabinet-tray hot-air drying for red chili pepper. Drying was conducted at varying levels of air temperature (40-70 oC), air velocity (0.5-2.0 m/s), and relative humidity (60-75%). The effect of drying conditions on drying time, drying coefficient, lag factor, drying efficiency, moisture ratio, effective moisture diffusivity, mass transfer coefficient, total energy consumption (TEC), specific energy consumption (SEC), energy utilization ratio (EUR), heat loss, energy efficiency, exergy loss, exergy efficiency, exergetic improvement potential (EIP), and exergy sustainability index (ESI)) was evaluated. Five different mass transfer models (Dincer-Dost, Bi-Di, Bi-S, Bi-G, and Bi-Re) were applied to determine the mass transfer parameters. A new drying mathematical model was developed for the prediction of drying kinetic, energy, and exergy parameters. Effective moisture diffusivity values of 1.58×10–8 - 5.10×10–8 m2/s and mass transfer coefficient values of 0.053×10–6 - 8.79×10–6 m/s over the drying conditions range were respectively obtained. The TEC, SEC, and EUR achieved over the range of drying conditions in the course of drying were in the range of 43.56-77.36 MJ, 49.0-87.02 MJ/kg, and 0.035-0.325, respectively. Heat loss and exergy loss varied from 0.16 to 2.39 MJ and from 0.026 to 0.622 kW, respectively. Drying, energy, and exergetic efficiency values obtained varied in the range of 2.80-8.25%, 2.69-7.91%, and 73-94.5%, respectively. EIP and the ESI values varied from 0.0068-0.114 kW and 3.70-18.18, respectively. The developed multivariate linear regression model provided an innovative model to predict drying kinetic, energy, and exergy parameters.
- Energy and Exergy analysis and selection of the appropriate operating
fluid for a combined power and hydrogen production system using a
Geothermal fueled ORC and a PEM electrolyzer
Abstract: This research aims to introduce an efficient power cycle that simultaneously produces power and hydrogen by PEM electrolyzer. This cycle is driven by geothermal energy. Comprehensive thermodynamic modeling (energy and exergy) has been performed to compare four different operating fluids' performance on the proposed system. EES software was used for modeling. A parametric study has also been applied to investigate the effect of important parameters on the system's energy and exergy performance. As a brief novelty statement, the unique model can be mentioned in which both power and chemicals can be produced, and hydrogen output can be used as a storage system that transforms energy into an energy carrier. The results showed that R245fa operating fluid with 3.5% and %67.6 of energy and exergy efficiency had the highest performance. The operating fluids R114, R600, and R236fa are also in the next ranks of performance characteristics. As the geothermal fluid temperature increases, the production of power and hydrogen increases, but the energy and exergy efficiency decrease. Also, it can be noted that the hydrogen unit significantly increases the exergy efficiency of the plant. As an example, in the R245fa case, it increases from 36% to 67.6%.
- Numerical study on bilateral stagger Cantor fractal baffles micromixer
Abstract: Changing the structure of microchannel or setting obstacles in microchannel has become an effective way to improve the mixing performance of passive micromixer. Here, we design a three-dimensional micromixer with fractal obstacles based on Cantor fractal principle. The effect of fractal obstacle level, micromixer height, spacing between fractal obstacles and different Re (Reynold number) on the mixing efficiency are studied. Some valuable conclusions are obtained. The micromixer with quadratic fractal obstacles has better mixing efficiency than the micromixer with primary fractal obstacles. With the increase of the micromixer height, the effective folding area of the fluid can be increased. When the spacing between the fractal barriers is 0µm, the mixing efficiency of the micromixer is better. The mixing efficiency of all micromixers can reach more than 90% at Re is less 0.1 or more than 40. When Re is 70 and 100, the fluid convection in the micromixer is very strong. Finally, a best micromixer CSM600(Cantor structure micromixer with height 600µm) is obtained. The mixing effect is superior to other micromixers under any conditions.
- Comparison and study of physicochemical, nitrogen, microbial, antioxidant,
bioactive, and sensory properties of Mahyaveh prepared in optimal
conditions with traditional Mahyaveh
Abstract: Mahyaveh is the name of a traditional Iranian fish sauce made from the fermentation of small and low-consumption fish, anchovies, and sardines, and contains essential amino acids, vitamins, salts, metal ions, and desirable fatty acids such as Docosahexaenoic acid and Eicosapentaenoic acid. Production conditions and fermentation time can be effective in improving nutritional value and improving its health capabilities. The general purpose of this study was to compare and evaluate the physicochemical, nitrogen, microbial, antioxidant, bioactive, and sensory peptides of Mahyaveh prepared in optimal conditions with traditional Mahyaveh. The results showed that the amount of fat, dry matter, ash, fiber, and carbohydrates of Mahyaveh prepared under optimal conditions was significantly (p≤0.05) higher than traditional Mahyaveh. The amount of moisture and protein of traditional Mahyaveh was significantly (p≤0.05) higher than Mahyaveh prepared in optimal conditions. The amount of total nitrogen, formalin nitrogen, amino nitrogen, proteolysis of essential amino acids, total phenol, and sensory evaluation score in Mahyaveh prepared under optimal conditions was significantly (p≤0.05) higher than the traditional Mahyaveh sample. The amount of trimethylamine, volatile nitrogen, IC50, and microbial load of Mahyaveh prepared under optimal conditions was significantly (p≤0.05) lower than traditional Mahyaveh. The results of this study showed that by optimizing the production conditions of Mahyaveh, fish sauces with higher nutritional value, greater safety, and more desirable sensory properties can be produced than traditional Mahyaveh.
- Empirical Study of Thermochemical for Heavy Oil Problems in Production
Wells
Abstract: Well "X" is an oil well located in South Sumatra, Indonesia, which started production (on stream) in June 2017 and is still producing today. The fluid contained has the characteristics of heavy oil with a value of 24.6ºAPI and a high pour point (HPPO) of 48ºC originating from the Talang Akar Formation reservoir. This well was closed after two months of production, the calculation result of the Colloidal Instability Index (CII) of 1.022 indicates that this value indicates instability of asphaltene in crude oil and can cause asphaltene deposits to form. One of the methodologies in overcoming this asphaltene problem is using thermochemical stimulation. This well has undergone two chemical injections using thermo-A1 (xylene, C8H10 12.5%) + thermo-B1 (toluene, C7H8 2.5%). increased, namely thermo-A1 (xylene, C8H10 15%) + thermo-B1 (toluene, C7H8 5%) resulted that the well only lasted 9 days with a rate of 75 BOPD which decreased oil production by 16% per day until shut-in on 18 January 2018 indication of deposition of large quantities of oil in the production tubing. Based on data from the EMR (Electric Memory Recorder) at a depth of 400 m from the surface, the resulting oil temperature is below the pour point, which is 48ºC. On July 22, 2018, thermal stimulation with thermochemical was carried out to overcome the problem of asphaltenes. This thermochemical stimulation can melt the asphaltene deposits that settle in the production tubing and can raise the temperature above the pouring point of the oil. The thermochemical stimulation has succeeded in making the well produce again with a Qoi of 325 BOPD and raising the wellhead temperature from 30ºC/86ºF to 50ºC/122ºF. The results of the economic analysis of this thermochemical stimulation activity indicated that this activity benefited USD 947,811.
- Effect of parameters on fiber diameters and the morphology of hybrid
electrospun cellulose acetate/chitosan/poly (ethylene oxide) nanofibers
Abstract: Electropsun nanofibers (ENFs) were fabricated from the mixture of cellulose acetate (CA), chitosan (CHI), and poly (ethylene oxide) using an acetic acid solution. The impact of CA/CHI ratio (0.5, 1, 1.5 wt %), CHI/PEO ratio (1, 1.5, 2 wt%), sodium dodecyl sulfate (SDS) (0, 1.5, 3% w/w) and ammonium oxalate (3%, w/w) on the diameter, tensile strength, elongation and porosity of the ENFs were optimized using response surface methodology-central composite rotatable design (RSM-CCRD). The results revealed that ENFs were formed of non-woven fibers with a maximum diameter of 113 nm. Second-order polynomial models with high R2 values (0.996–0.99) were developed using Cubic analysis. The optimum condition was identified to be at the compounded level of CA/CHI 1.5 wt%, CHI/PEO 1 wt%, and SDS 3% (w/v). At the best point, diameter, surface tension, elongation, and porosity of the fabricated ENFs were 96.07 nm, 0.054 N/mm2, 13.09 mm and 52.29 respectively.
- Sonochemically synthesized mesoporous pyrophanite- MnTiO3/TiO2
Abstract: Malachite green (MG) dye belongs to the triphenylmethane class, extensively employed in textile industries and its presence in aqueous environment exhibits a noxious impact on living beings. Thus, it’s being immensely important to remove the dye/residues from the environment matrix. Herein, the sonochemical synthesized adsorbent material -pyrophanite-MnTiO3/TiO2 nanoparticles (NPs) was utilized to expel the commercial Malachite green (MG) dye from the solution. The adsorption efficacy data indicates the maximum removal of MG (90.2%) is obtained for the NPs calcinated at 1000 °C (MT1). The adsorption material (MT1) is characterized by using different techniques including XRD, FE-SEM, EDX, FTIR, BJH, and BET. The XRD analysis indicates the formation of divergent phases viz. rutile TiO2 and MnTiO3. The FE-SEM depicts the formation of a nano-rod-like structure. The average size and percentage of void space of MT1 NPs are evaluated by using IMAGE J software. The hysteric loops from BET and BJH plots revealed the existence of type H3 hysteresis, confirming the mesoporous structure for MT1 NPs. The surface area, pore-volume, and pore size are found to be 61.245 m2/g, 0.139 cm3/g, and 2.0178 nm respectively. The pH, dye concentration, and temperature of the solution are optimized for the maximum removal of MG using MT1 NPs. Further, the adsorption isotherms, kinetics studies, and intra-particle studies indicative of the existence of monolayered second-order diffusion onto the surface of MT1 NPs. The adsorption process is endothermic, thermodynamically driven, and accompanied by an increase in entropy.
- Novel nanobiosensor design to detect cholic acid using multiwalled carbon
nanotube/TiO2 nanoparticle for 3α-Hydroxysteroid dehydrogenase
immobilization
Abstract: Determination of cholic acid concentration is a useful method to monitor liver diseases. We propose a rapid and simple method for measuring cholic acid. The development of a cholic acid electrochemical biosensor is described that is based on the modification of glassy carbon electrode surface using a mixture of carboxylated multiwalled carbon nanotube and titanium dioxide nanoparticles in chitosan solution and immobilization of 3α-hydroxysteroid dehydrogenase. The modification process of the sensing surface was characterized by Fourier transform infrared spectroscopy, Energy Diverse X-ray Spectrometry, Field Emission Scanning Electron Microscopy, and voltammetry techniques. A good correlation was demonstrated between cholic acid concentration and the peak currents in the presence of nicotinamide adenine dinucleotide. Using carboxylated multiwalled carbon nanotube and titanium dioxide nanoparticles for electrode modification showed more effective area than unmodified electrode at optimum pH of 6. Two linear ranges were obtained at 7.1 - 42.7, and 70.9-476.2 nM of cholic acid. Also, the detection limit was 6 nM and the sensitivities of the two ranges were obtained 956.9 and 28.7 µA/µM.
- Study of the Effect of Poly(ethylene glycol) on the Nifedipine
Microencapsulation and Release
Abstract: Nifedipine is a dihydropyridine derivate calcium channel blocker, suitable as first-line therapy for patients with hypertension. When blood pressure is high, nifedipine will prevent calcium to pass into cardiac and vascular smooth muscle cells. Nonetheless, nifedipine has a low elimination half-life that makes nifedipine needs to be consumed repeatedly to enhance its bioavailability, and thus, gives rise to nifedipine concentration in blood. Hence, a controlled drug delivery system is needed wherein the drug could be delivered at the desired time. One of the options in drug delivery is drug microencapsulation using a polymer as a coating material. In this study, nifedipine was coated with poly(D-L lactic acid) (PDLLA)/poly(ethylene glycol) (PEG) polyblend also polycaprolactone (PCL)/PEG polyblend using solvent evaporation technique. The effect of the mass composition of the polyblend and molecular weight of PEG on the encapsulation efficiency and drug release was investigated. Microcapsules with the variation of PDLLA/PEG and PCL/PEG composition and PEG molecular weight had encapsulation efficiency of about 90%-92%. Microcapsules with PDLLA/PEG600 (9/1) exhibited the highest drug release of 43.2% with an encapsulation efficiency of 91.96% whereas microcapsules with PCL/PEG400 (7/3) had the highest drug release of 44% with an encapsulation efficiency of 90.64%.
- Preparation, in-vitro evaluation, and delivery of colchicine via
polyacrylamide hydrogel
Abstract: Hydrogels have excellent biocompatibility and are widely used in biomedical applications. However, it is still a challenge to build a hydrogel with outstanding mechanical properties and multiple functions. In this study, a polyacrylamide (PAM) hydrogel with a uniform network structure was achieved through an ultraviolet (UV)-responsive organic crosslinking agent, and a higher mechanical strength PAM-Ag+ hydrogel was designed through the introduction of silver ion by metal coordination interaction. Various contents of N'N-bis(acryloyl)cysteamine (BACA) as cross-linker, acrylamide (AM) as monomer, and Irgacure 2959 as initiator were investigated to have an optimal combination of high strength. Thus, the PAM-Ag+ hydrogel exhibited excellent adhesive behavior that could be fixed to the human forearm and any part of the skin, such as the finger and elbow joint. In addition, the properties and biocompatibility evaluations of the tough hydrogel in medical wound dressing were investigated. Meanwhile, these results showed that PAM-Ag+ hydrogels possess high stretchable (2600%) and mechanical robust (2.55 MPa) properties. Excitingly, the release of colchicine (Col) more than 95% in 48 h demonstrated the hydrogel highly potential in medical dressing and drug release applications in virtue of the excellent moisture retention, permeability, water tightness, swelling ratio, and biocompatibility.
- Synthesis, characterization, crystal structure and density functional
investigation of dialkyl(phenyl((4-(phenyl diazenyl)phenyl) amino)methyl)
phosphonate
Abstract: The reaction of 4-phenylazo-phenylamine and benzaldehydes with dimethyl phosphite resulted to three new α-azoaminophosphonates in excellent yields. Molecular identification of synthesized compounds were probed using NMR, FT-IR and elemental analysis techniques. The single crystal X-ray diffraction studies were used to determine the molecular structure of dimethyl [(4-methoxyphenyl ((4-phenyl diazenyl) phenyl) amino) methyl] phosphonate. The synthesized molecule was crystallized in the monoclinic space group P21/c with a=11.213(2), b=19.205(4), c=11.429(2) Å, β = 116.95(3), V= 2193.8(8) Å3. Density functional theory calculation with B3LYP/6-311++G (2d, 2p) basis set have been used to determine geometry parameters and harmonic vibrational frequencies. The optimized geometrical parameters calculated by density functional theory show satisfactory agreement with experimental values.
- SYNTHESIS OF THIOPHENE BASED FLAVONE SCHIFF BASE DERIVATIVES AND A
COMPARISON OF BIOLOGICAL ACTIVITIES WITH FURANFLAVONE ANALOGS
Abstract: In this investigation, a series of thiophene-based flavone Schiff base derivatives were synthesized starting from phloroglucinol. Initially, the acetophenone derivative of phloroglucinol, 2-hydroxy-4,6-di-O-methyl phloroglucinol (3) was prepared by acetylation followed by selective O-methylation. Later, the compound 3 was condensed with thiophenealdehyde to obtain respective thiophene chalcone and was cyclized with I2/DMSO to get corresponding thiophene-based flavones intermediate. In the final stage, the titled Schiff base derivatives were obtained by formylation at the 8th position of the flavone skeleton followed by condensation with various amines. All the synthesized compounds were tested for their antibacterial and anticancer activities. Among the tested compounds, compound 8h (3-Cl, 4-NO2) showed good to excellent antibacterial activity on four microorganisms. Further, the compounds were compared with corresponding Schiff’s base analogs of furan-flavone Schiff's bases.
- Synthesis, characterization, X-ray diffraction analysis of a tridentate
Schiff base ligand and its complexes with Co(II), Fe(II), Pd(II) and
Ru(II): Bioactivity studies
Abstract: This study reports the synthesis of Co(II), Fe(II), Pd(II) and Ru(II) complexes with Schiff base obtained by the condensation of 2-amino-methyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxylate with salicylaldehyde. The characterization of the ligand and its complexes was arranged and studied by FT-IR, UV-Vis., 1H and 13C NMR, microanalyses (C, H, N, S), X-ray diffraction (XRD) analysis, magnetic susceptibility, mass spectra and thermogravimetry analysis (TGA) and further was screened for antimicrobial, antioxidant and antiradical activities. Antioxidant activity of the ligand and its metal complexes was examined by using different methods including the total antioxidant activity method, total reduction method and DPPH. The antimicrobial activities of Schiff base and metal complexes were investigated on bacterial and fungal strains. DNA cleavage experiments of metal complexes with supercoiled pBR322 DNA were detected by gel electrophoresis in the being of H2O2.
- The high performance of diethylhydroxylamine in comparison with hydrazine
for the removal of dissolved oxygen from boilers of power plant
Abstract: In boilers and hot water heating systems, hydrazine is used as one of the powerful reducing agents for eliminating oxygen. Due to the toxicity and carcinogenicity of this material, a suitable replacement named diethylhydroxylamine (DEHA) can be used. DEHA has low acute toxicity and animal tests do not show mutagenic activity. In this study, hydrazine and DEHA as deoxygenation materials were used in boilers of Tarasht power plant in Iran (Tehran). In different months (May to November), deoxygenation was examined by these two substances. The oxygen removal value of DEHA was equal to hydrazine and sometimes far better than it. The rate of deoxygenation reaction of DEHA was 40 ppb in most months of the year, but the number of peaks in hydrazine was greater (2 peaks with 50 ppb and 1 peak with 60 ppb). Hydrazine analysis is time-consuming, as well as pollutes the environment. On the other hand, DEHA of tests were completed sooner. Also, DEHA as an economical material with low toxicity can be a good alternative to hydrazine in boilers. This material can prevent boiler corrosion by oxygen removal.
- Quinolinyl triazole derivatives-Dominant Inhibitors for mild steel in
hydrochloric acid
Abstract: −Quinolinyl triazole derivatives 4-(4-chlorophenyl)-5-{[(5-chloroquinolin-8-yl)oxy]methyl}-2,4-dihydro-3H-1,2,4-triazole-3-thione (4-4CPCQMT), 4-(3-chlorophenyl)-5-{[(5-chloroquinolin-8-yl)oxy]methyl}-2,4-dihydro-3H-1,2,4-triazole-3-thione (4-3CPCQMT) and 4-(4-fluorophenyl)-5-{[(5-chloroquinolin-8-yl)oxy]methyl}-2,4-dihydro-3H-1,2,4-triazole-3-thione (4-4FPCQMT) are of great importance in pharmaceutical chemistry such as antifungal, antituberculosis, anticonvulsant, anticancer activities, etc. The present work highlights the synthesis of the quinolinyl triazole derivatives ((4-4CPCQMT, 4-3CPCQMTand 4-4FPCQMT). The substituents present and the compounds 4-4CPCQMT, 4-3CPCQMTand 4-4FPCQMT were confirmed by FTIR and NMR spectroscopy. These compounds having many reactive sites were used as inhibitors for mild steel in 1.0 M hydrochloric acid medium at 303 to 323K. An inhibition study was done by electrochemical measurement. The prevention efficiency is in the order 4-4FPCQMT>4-4CPCQMT>4-3CPCQMT. The surface morphology of the mild steel surface was done using SEM, AFM and, EDX.
- Optimization of Kerosene Aromatization over Ni/HY Catalysts using Response
Surface Methodology
Abstract: In this paper, several Ni/Y catalysts were prepared to perform kerosene aromatization. The Na+ cation of Y zeolite was exchanged with NH4+, and then Ni/HY catalysts were synthesized through the precipitation-deposition method. Properties of the samples were characterized by XRD, EDX, and BET. In addition, the Response Surface Method in combination with a three-factor Central Composite Design was employed to optimize the conditions of the reaction over Ni/HY catalysts. The three independent variables were: Ni content of the catalysts, reaction time, and temperature. Analysis of aromatic yield as the response was performed to survey the importance of these independent variables. Results of numerical optimization revealed that maximum operation conditions were 5%Ni-loading at a temperature 450ºC and a reaction time of 120min, in which aromatic yield was 55.74%. This was in agreement with the predicted aromatic content (52.62%) in this condition. Acceptable value for correlation coefficient (R2= 0.989), root mean square error (RMSE = 0.77), and standard error of prediction (SEP = 1.82) was obtained. These low values confirmed the adequacy and statistical significance of the model to predict an adequate response.
- Recent Advances in Bioplastics: Synthesis and Emerging Perspective
Abstract: Recently, the demands for biodegradable and renewable materials for several eco-sustain applications have increased tremendously. This rise in demand is connected to the growing environmental concerns over the extensive use of synthetic and non-biodegradable plastic packaging and the dumping of plastics waste in landfills. Biodegradable bioplastics are polymers that are mineralized into carbon dioxide, methane, water, inorganic compounds, or biomass by specific microorganisms by enzymatic action. As a result, they could be a viable and environmentally friendly alternative to petrochemical plastics. Bioplastic delivers precisely as per demand exhibiting several advantages: lower carbon footprint, energy efficiency, non-hazardous, stable, cost-efficient and eco-friendly. Herein, a major focus is given on the discussion of the bioplastics production from various sources, their type and the role of additives to strengthen their chemical and physical properties. This review article goal to provide information about the bioplastic synthesis concerning the recycling of bioplastics, thermoplastic biocomposites and their blends with a special focus on mechanical recycling of bio-based materials. Additionally, the utilization of these bioplastics in various industries such as the food packaging industry, the automotive industry has been enlightened.
- Effect of culture media and feeding composition on production increasing
of Hyaluronic acid in batch and fed-batch cultures of Streptococcus
zooepidemicus
Abstract: Hyaluronic acid as a high value-added biological product is one of the most widely used biopolymers used in industry and medicine. This study aimed to increase the hyaluronic acid production by carefully examining the effect of glucose concentration in batch and Fed-Batch cultures and the effect of controlling the residual glucose concentration in Fed-Batch culture on hyaluronic acid production. The effect of two different sources of hydrolyzed casein nitrogen and tryptone soy broth on HA production was compared. The effect of glucose concentrations on HA production was investigated in batch and fed-batch cultures. Also, the effect of glucose concentrations on HA production was investigated in batch and fed-batch cultures. Under the optimal conditions, including casein hydrolyzed 20 g.L-1 and initial glucose concentration of 30 g.L-11 liter in batch culture, 4.4 g.L-1HA was obtained. Also, the constant feeding with 30 g.L-1 of glucose increased HA production to 5.8 g.L-1. This is one of the highest values of HA production ever reported. Weakening the glycolytic cycle and slowing down the growth rate of biomass influence increasing hyaluronic acid production. Also, control glucose concentration as the energy and carbon source of cells, by fed-batch culture, the cellular pathway can be directed to produce more hyaluronic acid and achieve greater yield.
- A Taguchi Optimization Study about The Dissolution of Colemanite in
Ammonium Bisulfate (NH4HSO4) Solution
Abstract: In this study, the optimum conditions of the dissolution of colemanite (2CaO.3B2O3.5H2O) ore in ammonium bisulfate (NH4HSO4) solution were examined by using Taguchi fractional design methods, and an alternative reactant for boric acid extraction process from colemanite ore was specified. The studied parameters and optimum conditions for the dissolution process were in the following; reaction temperature: 50˚C, solid/liquid ratio: 0.1 g/mL, particle size: -80 mesh, mixing speed: 600 rpm and reaction time: 25 minutes. Particle size, mixing speed and reaction time had the most significant effect on dissolution, when compared to the others. Accordingly, the dissolution efficiency of colemanite was found to be 99.54% under optimum conditions, and using NH4HSO4 as a solvent enabled the selective separation of boron from the colemanite ore. The ammonium sulphate formed as a by-product was converted into NH4HSO4 by the addition of appropriate stoichiometric amount of sulfuric acid and fed back into the dissolution vessel.
- Treatment of Sugar Industry Wastewater with by Homogeneous and
Heterogeneous Fenton Oxidation using the SnO2 Supported Iron Catalysts:
Determine of Optimum Conditions
Abstract: Since the wastewater of the sugar industry contains a high level of organic pollutants, the discharge of these water to the environment causes significant environmental problems. Therefore, it is very important to treat sugar industry wastewater for a clean and sustainable environment. In this study, color and COD removal efficiencies from sugar industry wastewater were compared by applying homogeneous Fenton and heterogeneous Fenton processes. The parameters effecting the oxidation process such as iron ion concentration, catalyst amount, hydrogen peroxide concentration, pH, temperature and reaction time were examined and optimum experimental conditions were determined. Synthesized Fe(III)/SnO2 was used as catalyst in the heterogeneous Fenton process. It was aimed to eliminate the iron-containing sludge formation, which was the disadvantage of the homogeneous Fenton process, by the heterogeneous Fenton process. Under the optimum conditions, in the homogeneous Fenton process 81% color and 70% COD removal efficieny and in the heterogeneous Fenton process 94% color and 80% COD removal efficiecy were achieved. These results showed that the heterogeneous Fenton method is more suitable for sugar industry wastewater treatment.
- Experimental Study of Methane Hydrate Formation in the Presence and
Absence of Tetra n-butylammonium Chloride and Sodium Dodecyl Sulfate
Abstract: The kinetics of methane hydrate formation in the presence of tetra n-butylammonium chloride (TBAC) and sodium dodecyl sulfate (SDS) is investigated in this research. The hydrate formation reactions are carried out in the isothermal condition of 278.15 K in a 169 cm3 stirred batch reactor. The amount of gas uptake and the storage capacity of methane hydrate formation are calculated. Results indicate that utilization of TBAC with a concentration of (3 and 5) wt% and SDS with a concentration of 400 ppm increases the amount of gas consumption and the storage capacity of methane hydrate formation. Utilization of TBAC along with SDS decreases the amount of gas consumption and storage capacity, compared to aqueous the solution of SDS. Investigation of the impact of pressure on the gas hydrate formation indicates that by increasing the initial pressure of the cell form 6 MPa to 8 MPa, the amount of gas consumption and the storage capacity of methane hydrate formation increases, considerably.
- Review of CO2 capture using absorption and adsorption technologies
Abstract: In this work, we tried to explore the review of CO2 capture using absorption and adsorption technologies. For this purpose, also, besides to literature reviewing investigate the effect of some operational parameters such as temperature, pressure, amine concentration, solution flow rate, and the adsorbent loading on the CO2 removal efficiency and CO2 capture capacity. The results demonstrated that the flow rate of liquid and concentration of amine has a positive effect on the removal efficiency and the CO2 flow rate has a negative effect. The results in the adsorption part indicated the pressure had a positive effect on the equilibrium adsorption capacity and the adsorbent loading and temperature had a negative effect. Moreover, the absorption of CO2 into three ZrO2, TiO2, and ZnO nanofluid at Pz and DEA solution was investigated. The results represented that the loading of nanoparticles and speed of stirrer have an optimum value for CO2 removal efficiency. The optimum value was 0.05 wt%, 0.05 wt%, and 0.1 wt%, for ZrO2, TiO2, and ZnO nanoparticles, respectively. Furthermore, the CO2 removal efficiency increased first with an increase of the stirring speed up to 200 rpm, and then begins to decrease as the stirrer speed increases above 200 rpm.
- Radiation induced degradation of Congo red dye over unsupported and
activated carbon supported strontium oxide nanoparticles
Abstract: The textile industry produces a significant amount of liquid effluent pollutants due to the vast amounts of water used in fabric processing. This has resulted in significant water pollution worldwide. The reduction of these dye compounds from industrial wastewater has been achieved using chemical, physical, and biological methods. However, these approaches are time-consuming, costly, and pose disposal problems. Currently, photocatalytic degradation by nanoparticles is attracting significant attention. In this regard, Activated carbon supported and unsupported SrO nanoparticles were synthesized by the wet chemical co-precipitation method. The nanoparticles were characterized by XRD, SEM, EDX, and FT-IR. The Strontium oxide (SrO) and Activated carbon-supported Strontium oxide (Ac/SrO) nanoparticles (NPs) were used as photocatalysts for the photodegradation of Congo red dye in an aqueous medium under UV irradiation. The unsupported SrO and AC/SrO NPs degraded about 93.3% and 97.6% of dye, respectively, within 100 minutes of irradiation time. The maximum degradation of the dye was achieved at pH 4, 0.06 g of catalyst dose, 15 ppm dye concentration, and a temperature of 45℃. The data were best fitted with pseudo-first-order kinetics. The activity of the recovered catalyst was also examined.
- Experimental Analysis of Polymer Coated Aggregate in Comparison To
Ordinary Road Material
Abstract: Worldwide the broad usage of plastic has resulted in the massive production of plastic pollution, which is incinerated, put in landfills and oceans. The technique of coating road aggregate with plastic has a good potential to deal with this global issue. The unique physical, mechanical and thermal properties polymer offers effective binding, less moisture retention, less susceptibility to void formation. This research will ultimately reflect plastic waste management and road enhancement. The main purpose of this experimental study is to predict and highlight the effect of varying plastic composition coating on aggregate and select the best performing sample. For this study, samples of polymer-coated aggregates of different ratios are created, further tested for their enhancement in properties. To create polymer-coated aggregate, we have used recycled aggregates, Grade 70 bitumen, and polyethylene bags from waste. To coat the aggregates used "dry-mix process."The effectiveness of the coating with varying plastic compositions was measured using seven different tests. It was hypothesized that incorporating plastic would enhance the properties of aggregate and increase the durability and workability of road materials. The tests results supported the hypothesis. Standard ranges were used to perform a comparative study between polymer-coated aggregate and conventional aggregate. Nearly all test's plastic composition >8% and less than 15% have shown good results, but the optimum value for all tests is achieved by sample with 12% plastic coating. Although this study supports that plastic incorporation is a better idea to enhance the longevity of roads, more research is required to explore the underlying mechanism of plastic coating and its long-term outcomes.
- Effect of nitrogen deposition on Soil CO2 emission during freezing-thawing
incubation period
Abstract: Due to the traditional analysis method on the influence of soil nitrogen deposition on soil emissions during the freezing and thawing period, the initial impact of nitrogen deposition on soil emissions during the freezing and thawing incubation period was not analyzed, resulting in insufficient accuracy of the later analysis results. A new method was proposed to analyze the effect of nitrogen deposition on Soil emission during freeze-thaw cultivation.On this basis, the contents of soil temperature, moisture, inorganic nitrogen and soluble carbon were determined. Three freeze-thaw models of nitrogen deposition levels were established. The influence of nitrogen deposition on Soil emission and the effect of nitrogen deposition on emission in alpine wetland were studied by multivariate variance analysis. The effect of nitrogen deposition on emission of alpine wetland was studied. The results showed that different soil temperature and moisture content had great influence on the seasonal variation of soil flux, which was generally consistent with the single peak of soil temperature, but highly consistent with the variation of soil moisture content in different growth periods. Nitrogen treatment changed the DOC content of soil organic matter. DOC content in mineral layer and organic layer increased significantly in low and medium nitrogen treatments. The emission of soil in freezing period is lower than that in normal temperature period, and that in multiple freezing period is less than that in one freezing period. The emission rate of soil under freeze-thaw condition is the smallest, and the emission rate of soil after thaw is the largest. Appropriate nitrogen deposition can promote soil emission, while high nitrogen deposition can inhibit emission.
- A 2E Analysis and Optimization of a Hybrid Solar
Humidification-Dehumidification Water Desalination System and Solar Water
Heater
Abstract: This study presents an energy-exergy analysis of a Humidification-Dehumidification (HD) solar water desalination system. The extensive application of the HD system lies in its low energy consumption and ability to exploit solar energy to supply all the heat energy demands. The unsteady governing equations were solved until the system reached a steady state. The simulations were done with the Euler approach to solving the system of energy balance equations numerically. This study's main goal was to investigate the effect of different configurations of the hybrid system and various operating conditions on the performance of the solar HD water desalination system. The optimum configuration was selected based on thermodynamic and exergy analyses. The effects of important parameters such as inlet water and air mass flow rate in the humidifier and dehumidifier water temperature and mass flow rate on the system's operation were studied. This paper also explored the feasibility of the extra heat as a domestic water heater under various conditions. Based on exergy analysis, it is shown that the solar desalination system with air-water preheater with the power of 1057.9 W had the most exergy destruction in comparison with the two other systems (i.e., water preheater system and air preheater system with the respective exergy destructions of 901.3 W and 75.3 W). Comparing the values of freshwater production, exergy destruction, and exergy efficiency, the solar system with a water preheater was selected as the optimum one.
- Response Surface Methodology and Artificial Neural Networks (ANNs) (RSM)
Pectin extraction from banana peel: a modeling and optimization approach
Abstract: In the present study, the extraction of pectin from banana peel (Musa sp.) was optimized using artificial neural network and response surface methodology on the yield and degree of esterification obtained using microwave-assisted extraction methods. The individual, quadratic and interactive effect of process variables (temperature, time, liquid – solid ratio and pH) on the extracted pectin yield and DE of the extract were studied. The results showed that properly trained artificial neural network model was found to be more accurate in prediction as compared to response surface model method. The optimum conditions were found to be temperature of 60oC, extraction time of 102 min, liquid – solid ratio of 40 % (v/w) and pH of 2.7 and within the desirable range of the order of 0.853. The yield of pectin and degree of esterification under these optimum conditions were 14.34% and 63.58, respectively. Temperature, time, liquid – solid ratio and pH revealed a significant (p < 0.05) effect on the pectin yield and degree of esterification. Based on the value of methoxyl content and degree of esterification the extracted pectin was categorized as high methoxyl pectin. Generally, the findings of the study show that banana peel can be explored as a promising alternative for the commercial production of pectin.
- 2E analysis of a renewable hydrogen plant based on bio-steam
reforming(BSR) system
Abstract: In this paper, a biogas water vapor reforming system for hydrogen production is presented. The biogas mixture contains a large percentage of methane and carbon dioxide and small amounts of other gases. A thermodynamic modeling (energy and exergy) is performed on the proposed system and a study on the effect of various system parameters such as temperature and molar ratio of carbon dioxide to methane in the biogas mixture on hydrogen production, energy, and exergy efficiency of the whole system has been done in this paper. The results show that the increase in steam reforming reactors in a constant molar ratio of carbon dioxide to methane in the biogas mixture increases hydrogen production and the energy and exergy efficiency of the system. However, increasing the molar ratio of carbon dioxide to methane in the biogas mixture at high temperatures reduces hydrogen production per mole of methane, and as a result, the energy and exergy efficiency of the whole system are reduced. Also, the highest energy and exergy efficiency of the whole system in the conditions where the amount of hydrogen production is maximum is 52% and 42%, respectively.
- Simulation and exergy and exergoeconomic analysis of an associated gas GTL
recovery plant (Case study: 4 and 5 phases of South Pars)
Abstract: In the last one hundred years, the increase in the use of fossil fuels in various industries, including refineries, petrochemicals, industrial complexes, etc., to achieve more production, has led to an increase in various pollutants in the world and environmental concerns, various economic costs, and health costs. Imposed on human beings. One of the most important sources of environmental pollution is industrial fluoride gases. According to global statistics, Iran is known as the third country to burn these gases. Reducing the emissions of these gases is one of the great goals of the international community. It seems necessary to study various methods such as converting gas to liquid to recover Flare gas. This research has simulated a gas-to-liquid conversion unit using the Flare gas output data of the south pars natural gas processing plant in Aspen Hysys V11 software. This unit is then evaluated and optimized by the exergy analysis method. The simulation output shows that when Flare gas is used to liquid the unit’s raw material, 1549 barrels of gas to liquid products per day will be obtained from this unit. Investigation of this case shows that one of the appropriate solutions to recover Flare gas can be to create a gas to the liquid conversion unit with energy and exergy efficiency of 65% and 69%.
- Modeling and thermodynamic analysis of Municipal Solid Waste Dryer: A
parametric study
Abstract: Due to the landfill leachate and the lack of drainage beds for collecting and directing leachate, especially in developing countries, the need to study municipal solid waste (MSW) dryers is of particular importance. According to the technical literature, so far no comprehensive study has been performed on MSW dryers considering with the actual components of the waste and the moisture content above 40%. Here a comprehensive study for wet MSW dryers consists of three different parts is performed. In the first part, a semi-theoretical mathematical model is developed to calculate the drying rate (internal) of wet MSW. For this purpose, with the laboratory results in the technical literature and Statistica software, a suitable mathematical model for drying MSW is validated and determined. Then, the external drying rate is determined according to the type of dryer selected and after its validation; it is compared with the internal drying rate. In the second and third parts, after validation of EES developed code, energy and exergy analysis are reviewed and finally parametric study is performed to investigate the effects of different parameters on energy and exergy efficiencies of unsorted wet MSW drying process. The results show that the best model for drying the unsorted MSW is the logarithmic model with a corresponding R^2 of 0.999. The internal and external evaporation rates are 0.157 and 0.165 kg/s and it is seen these two rates are well matched together and differ by only 5%. The energy efficiency and exergy efficiency of the dryer are 13.92% and 2.91%, respectively. According to the parametric study, the inlet air temperature and the temperature of inlet MSW have the greatest effect on energy efficiency, respectively. Inlet air conditions such as absolute humidity of inlet air and atmosphere pressure have the greatest effect on the exergy efficiency of MSW drying.
- Magnetically responsive nanocomposite hydrogels for controlled release of
ciprofloxacin
Abstract: In spite of the huge work concerning the applicability of polymeric hydrogels in the field of drug release, it is still promising and interesting area for more improvements and trials for preparing new designed drug delivery systems. In this study, acrylamide and hydroxyl ethyl methacrylate (HEMA) copolymer hydrogels were prepared by the aid of gamma radiation and the P(AAM/HEMA) nanocomposite hydrogels were obtained by in situ absorption and reduction method of iron salts and silver nitrates (AgNO3) to form P(AAM/HEMA)-Fe3O4 and P(AAM/HEMA)-Ag nanocomposites. The prepared hydrogels and the formed nanoparticles were studied by various techniques; FTIR, TEM, SEM and the gel content and swelling behavior were evaluated. FTIR confirmed the high interaction, which resulted in successful formation of the AAm/HEMA copolymer hydrogel. TEM provides a good evaluation for the size of the formed Fe3O4 and Ag NPs to be 12 and 8.5 nm respectively. The prepared hydrogels and nanocomposites hydrogels were examined as drug delivery systems for Ciprofloxacin HCl as model drug. The results showed that PAM/HEMA-Fe3O4 nanocomposite gave the suitable load and release behavior towards Ciprofloxacin HCl.
- COMPARATIVE STUDY ON STRUCTURING AND PHOTOCATALYTIC ACTIVITY OF
NANOTITANIA EMBOSSED WITH ORGANIC EXTRACTS
Abstract: Several extensive research studies have explored the advantages of green templates in the synthesis of structure and morphology-controlled photocatalytic nano materials. This paper compares the potential aspect of zingiber rhizome extract (ZE) and tapioca starch extract (TS) in modifying the surface and optical properties of titania nano particles (TNP) synthesized by sol-gel technique. The synthesized nano catalysts were characterized using various physico-chemical techniques. While zingiber extract promote effectively favored the formation of dual anatase and rutile phases, tapioca extract ended with single anatase phase titania, were examined for the degradation of Congo red in the presence of sunlight. The photo mineralization and recyclability of catalysts have been evaluated through Total Organic Content analysis. The easy recovery and reusability of bio synthesized nano catalysts with good control over the grain size, enable them to be an implicit novel green templates in the successful synthesis of photoactive mesoporous nano titania.
- Applying Differentiated Retinal Cell for Age-related Macular Degeneration
Treatment
Abstract: Age-related macular degeneration (AMD) is one of the retinal degenerative diseases associated with some degree of dysfunction and loss of retinal pigmented epithelium (RPE) cells and leads to permanent sight loss. Available treatments only slow down its progression. Applying scaffold to help RPE cells for proliferation and making layer has been proposed as a promising approach to treat this group of diseases. In this study, a fuzzy system was used to optimize the situation of making a scaffold. For better adhesion and proliferation of cells, the polycaprolactone scaffold's surface was modified by alkaline hydrolysis and plasma. Some analyses, such as water uptake and biodegradation rate, were done. Then, differentiated human embryonic stem cells (hESCs) were cultured on several groups of scaffolds. Finally, the viability, proliferation, and morphology of differentiated hESC-RPE cells on all groups of the scaffolds were investigated. The nanofibers' diameter was minimized by optimizing voltage and solution concentration with a fuzzy model for the first time, which obtained 110.5 nm, 18.9 kV, and 0.065 g/mL (w/v), respectively. Immersion time of scaffold in alkaline solution and solution concentration during surface modification were achieved 4.3 M and 104 minutes, respectively, by response surface methodology. Results of the MTT assay showed that the hydrolyzed group had a high proliferation of cells. Scanning electron microscopy observation of cell morphology after 60 days confirmed this result. In conclusion, our results demonstrate that the hydrolyzed scaffold is a suitable bed for cell proliferation, a good option for AMD treatment.
- Comparison of Two Purification Methods for Beta Toxin of Clostridium
perfringens Type B
Abstract: Clostridium perfringens is an anaerobic bacterium that among its strains, only types B and C can produce beta-toxin. Beta-toxin plays an important role in many human and animal diseases and has detrimental effects on the intestine. The present study aimed to compare two purification methods for the extraction of beta-toxin from C. perfringens type B. As the first method, beta-toxin was purified using ammonium sulfate precipitation, column chromatography (Sephadex G-25), and ion-exchange chromatography (DEAE Sephadex), while the second method employed affinity chromatography. Hemolysis activity and protein content were measured in each step of purifications. The purity of beta-toxin was monitored in each step using SDS-PAGE. According to the results, a comparison of these two methods indicated that the yield of the first method was 82.8%, and the yield of the second method was 90.1%. The specific activity values for the first and second methods were calculated to be 2368.1 U/mg and 164.5 U/mg, respectively. Our results show that affinity chromatography could be used to purify beta-toxin from clostridium perfringens type B with high purity and specific activity (4370 HU/mg).
- Simulated body fluids prepared with natural buffers and system for active
pH regulation
Abstract: The current study focuses on creating an initial highly alkaline simulated body fluid whose pH can be decreased to a physiological range by adding CO2 (protein-free simulated body fluid) or a combination of CO2 and human proteins (protein-containing simulated body fluid). The effects of dissolved human proteins, Ca2+ ions, and immersed plasma-sprayed hydroxyapatite coatings on the pH and chemical instability of prepared simulated body fluids were investigated. The physiological concentration of dissolved human proteins decreased the pH instability in prepared simulated body fluids by 60% and the physiological concentration of dissolved Ca2+ ions by 15%. The effect of immersing the hydroxyapatite coatings was negligible. In terms of chemical instability, the dissolution of Ca2+ ions caused the blurring of protein-free simulated body fluids after 0.6-1.0 h. In protein-containing simulated body fluids, this phenomenon was undetectable due to their opacity. The effects of human protein presence on the carbonated-apatite-forming ability on the surfaces of immersed hydroxyapatite coatings in the prepared simulated body fluids were also assessed. The experiments validated the bioactivity of plasma-sprayed hydroxyapatite coatings in the prepared simulated body fluids, regardless of protein presence. On the other hand, under the different experimental conditions (unregulated or regulated pH), the human protein presence had an inhibitory (unregulated pH) or indifferent/promoting (regulated pH) influence on the carbonated-apatite-forming ability. The results of the present study are discussed, as well as the strengths and shortcomings of the prepared simulated body fluids, and are compared to those of previous relevant investigations.
- Investigation of Physicochemical Properties of Grape Juice and Apple juice
Containing Anthocyanin Pigment Extracted from Roselle (Hibiscus
sabdariffa) Petals
Abstract: Colors are used in foods to make them more appealing. Roselle petals contain functional compounds such as anthocyanins and polyphenols in addition to natural pigments. The objective of this study was to investigate the physicochemical properties of grape and apple juice-based drinks containing anthocyanin extracted from roselle petals. To do this, the extracted pigments were added to apple juice and grape juice at concentrations of 5 and 10% w/w. pH, acidity, total phenolic content, anthocyanin, degradation index, hydroxymethyl furfural (HMF) as well as the sensory parameters of the drink samples stored at 4 and 25 ℃ for 30 days were measured. The results showed that pH and acidity increased with time. Anthocyanin and total phenolic content decreased and degradation index and HMF content increased over time. Apple juice drink containing 10% anthocyanin stored at 4 ℃ had the highest polyphenolic and anthocyanin content. The results of the sensory evaluation revealed that the apple juice treatment containing 10% anthocyanin stored at 4 ℃ was the superior treatment due to its highest bioactive compounds and sensory score.
- Spectral and Electrochemical Sensing Studies of Novel Tetradentate Schiff
bases, having Enhanced Antifungal activity, containing Ferrocene and
Aromatic moieties attached Imines
Abstract: Multi metal ion sensing unsymmetrical Schiff bases containing ferrocene group attached imine at one side and aromatic moiety connected azomethine on the other side have been synthesized. Titration studies coupled with UV-Visible spectrophotometer exposes the binding aptitude of new receptors. Development of MLCT band near 457 nm for the coordination of Cu2+ ions with new ligands is also noticed. Electrochemical studies of receptor solutions with added metal ions expose quasi reversible process by giving superfluous ΔEP values (146-161 mV, than the expected 59 mV). Concentration of metal ions required for effective sensing is calculated from the percentage amount of ΔIpa extracted from the Ipa data. Results obtained in computational molecular docking studies and in- vitro analysis invite more focused research by pharmacist to develop new formulations for antifungal medicines.
- Optimization process for the synthesis of polyol-oleates from Malaysian
unsaturated palm fatty acid distillate
Abstract: Palm fatty acid distillate (PFAD) is cheap and valuable by product of edible oil processing industries. Palm fatty acid distillates are generally used in the soap industry, animal feed industry, and as raw materials for oleochemical industries, in the manufacture of candles, cosmetics and toiletries. Other applications include their use as food emulsifiers, an aid in rubber processing, in flavours and fragrance industries well as in pharmaceutical products. Vitamin E has been extracted commercially from PFAD for encapsulation. This study was carried out to determine the optimization conditions for the esterification of Malaysian PFAD with high degree polyhydric alcohols (TMP, Di-TMP, PE, and Di-PE) in the presence of sulphuric acid as catalyst based on four reaction parameters; reaction temperature (°C), reaction time (h), effect of different alcohols, and molar ratios. The results show that, high conversion of 89% USFA-TMP ester was observed at 150°C, the optimal time for the esterification is at 6 h to obtain 91% tri-ester yield, TMP ester produced the highest yield percentage (91%) and the optimum molar ratios were 3.5:1 (USFA: TMP), 4.5:1 (USFA-Di-TMP and USFA: PE) and 6.5:1 (USFA: Di-PE).
- Removal of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II)
from water solutions using activated carbon based on cherry kernel shell
powder
Abstract: In this work, a method for preparing activated carbon based on cherry kernel shell (AC-CKS) was investigated using two consecutive steps: chemical activation with H2SO4 agent and thermal activation in air. For the first time, AC-CKS product is used for the removal of numerous metal ions such Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II), and Pb(II) from water solutions. The AC-CKS was characterized using EA, FTIR, SEM, EDX, and XRF techniques. The AC-CKS obtained by heating at 600 °C showed product with higher iodine number and invariably micro-size pores compared to those obtained by heating at 55°C and 400°C. Adsorption capacity of AC-CKS600 was tested in removal of previously mentioned metal ions. The essential parameters affecting the removal of metal ions were studied. The results showed maximum adsorption of 99.0% for Cr(III), 91.7% for Fe(III), 62.0% for Cu(II), 59.3% for Pb(II), 42.0% for Zn(II), 28.0% for Ni(II), and 26.9% for Mn(II). The adsorption data of most metal ions fitted well with Langmuir model. The maximum adsorption capacity followed the sequence: Cr(10.75 mg/g)>Fe(10.15 mg/g)>Cu(7.58 mg/g)>Pb(7.36 mg/g)>Zn(6.08 mg/g)>Ni(2.83 mg/g)>Mn(2.29 mg/g). The adsorption kinetics was tested for the pseudo-first order and pseudo-second order. The rate constants of adsorption for all studied metal ions were calculated. Good correlation coefficients (R2>0.9972) were obtained for the pseudo-second order kinetic model showing that all metal ions uptake processes followed the pseudo-second order rate expression. Desorption studies showed the quantitative recovery of metal ions in the range from 89.4% for Pb(II) to 94% for Cr(III). According to the adsorption model applied in this work, AC-CKS600 product could be recommended for the removal of Cr(III), Fe(III), Cu(II), Pb(II), and Zn(II) from aqueous solutions.
- Removal of Oxytetracycline Using Polymer Coated Magnetıc Nanopartıcular
Activated Carbon: Synthesıs, Characterisation and adsorption isotherms
and kinetics studies
Abstract: In the presented study, the removal of oxytetracycline (OTC) from aqueous solution by adsorption was investigated onto active carbon (AC), magnetic activated carbon (MagAC), styrene-butadiene styrene magnetic activated carbon (SBS/MagAC) and poly charbon magnetic activated carbon (PC/MagAC). The process optimization was carried by investigating the effects of pH, temperature, solid-liquid ratio, adsorbent type and initial concentrations. The data showed that adsorption reached equilibrium in as little as one hour. less adsorption at low pH values and more at approximately 5.0 values. However, all the materials performed well at room temperature when the situation is examined in terms of kinetics. It was also observed that AC, MagAC and PC/MagAC are more effective than SBS/MagAC and the initial concentration decreased from 100 ppm to 20 ppm with adsorbents. In addition, at lower concentrations, when 25ppm and 50 ppm were used , it was obsedved to 2.5 ppm and 5.0ppm values. The kinetic results presented that pseudo-second-order model (r2 ⩾ 0.99) was more effective than that of pseudo-first-order model (r2 < 0.90). Also, Intra-particle kinetic model in adsorption process exhibited two different stages with diffusion of inter-particle and external diffusion. Adsorption isotherms for all adsorbents were fitted to Langmuire models more effectively than Freundlich models (r2 ⩾ 0.99). Thermodynamics parameters were also calculated. It is seen that OTC can be removed more easily from the aqueous medium by using magnetic and polymeric material.
- Removal Studies of S2- Based on SBA-15- Pb(II) Composite
Abstract: SBA-15 nano mesoporous molecular sieve was successfully synthesized by hydrothermal method and after its adsorption of Pb2+ the prepared material was used to adsorb S2- from aqueous solution. The surface and pore structure of SBA-15, the (SBA-15)-Pb(II) and the composite material of S2- adsorbed by the (SBA-15)-Pb(II) were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and low temperature nitrogen adsorption-desorption isotherm. The effects of solution acidity, S2- concentration, contact time and temperature on the adsorption of S2- by the (SBA-15)-Pb(II) were investigated. The optimized adsorption conditions were obtained. The adsorption rate for S2- by the (SBA-15)-Pb(II) reached 96.33 %. The change of Gibbs free energy in the adsorption process, , can judge that the adsorption process is spontaneous. The enthalpy change in the adsorption process is less than zero, showing that the adsorption process is exothermic reaction. The negative value of entropy change indicates that the adsorption process is a process of entropy reduction. The adsorption of S2- by the (SBA-15)-Pb(II) belongs to the pseudo-second-order kinetics. Freundlich isothermal adsorption equation can better describe the adsorption process. A novel method has been developed to adsorb S2- from wastewater.
- Photocatalytic Degradation of Penicillin v Using Bi2O3/Ag/TiO2 Thin Film
in a Spinning Disc Photoreactor under Blue LED Illumination
Abstract: In this study, a novel spinning disc photoreactor (SDPR) was designed for the treatment of penicillin v (PV) as objective contaminants under blue light-emitting diodes (LEDs) irradiation. To this end, visible light-activated Bi2O3/Ag/TiO2 catalyst thin film was deposited onto the surface of a ceramic disc support through a facile sol-gel spin coating technique. The synthesized film fully characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS) and diffuse reflectance spectroscopy (DRS)techniques. A central composite design (CCD) was exploited to optimize the operative variables including illumination time, rotational speed, initial PV concentration and solution flow rate. The PV photodegradation efficiency of 97.67% was achieved at optimal operational conditions involving 80 minutes of illumination time, rotational speed of 180 rpm, initial PV concentration of 30 mg/L and solution flow rate of 0.8 L/min. Furthermore, Langmuir-Hinshelwood (L–H) kinetic model well fitted the empirical data. Findings indicated that the developed SDPR can be a prominent alternative technology for the CPX degradation process from wastewater.
- Reduction of Dust Output from Prilling Tower of Khorasan Petrochemical
Company
Abstract: Urea (NH2CONH2) is very important for the agriculture industry as a nitrogen-rich fertilizer. Urea synthesizes from ammonia (NH3) and carbon dioxide (CO2) at 170 - 180˚C and 143 kg / cm3. This study aims to reduce the amount of urea dust from the flue gas emitted from the Urea Prilling Tower of Khorasan Petrochemical Company. Since the conversion process of molten urea to urea seeds produces a lot of dust, a large amount of environmental pollution caused by this industry can be prevented by examining various factors in dust production in this plant. Thus, the project was divided and implemented into six general phases (Six Sigma project) include problem definition and study phase, measurement and estimation of time and cost required, preliminary analysis, design, and implementation (DMAIC methodology). After implementing the plan, a significant reduction in urea emissions was observed, about 38%. Therefore, the results show that Six Sigma is a useful tool that can accurately predict the removal of urea dust from flue gases.
- Acoustofluidic separation of microparticles: a numerical study
Abstract: In this paper, two-dimensional simulations are performed to separate polystyrene (PS) and polymethyl methacrylate (PMMA) particles suspended in water using an acoustic field. The acoustic waves are generated by two aluminum interdigitated transducers (IDTs) over a piezoelectric substrate. The effect of input power, inlet flow rate, acoustic frequency, and distance between IDTs and channel on separation efficiency is evaluated by considering channel thickness. It is observed that the separation efficiency is enhanced by increasing acoustic frequency and input power. Also, as the inlet flow rate and distance between IDTs and channel decrease, the separation efficiency increases. The optimum values for input power, flow rate, frequency, and distance are 1.4 W, 0.2 ml/min, 5 MHz, and 75 µm, respectively, and a maximum separation of 88% is achieved.
- Sodium hydroxide solution pretreatment effect on anaerobic digestion
process under mesophilic conditions
Abstract: Biogas, latent energy inside organic components, is a by-product of anaerobic digestion process. Biogas validity depend on methane composition value. Some organic compounds are not easily accessible to active microorganisms in anaerobic digestion process due to their nature and structure. These compounds are made available to microorganisms by pretreatment and methane composition is increased. In this study, alkaline pretreatment of solid organic wastes by sodium hydroxide solution was studied through the anaerobic digestion laboratory apparatus. A mixed feed of organic solid waste, previous stage digested matter and bovine excrement were considered. Three tests were designed. First test, feed was without pretreatment. Solid organic wastes of the second and third tests were immersed in 0.5 M and 0.1 M sodium hydroxide solution for 24 hours in the laboratory, respectively. The set up was subjected to -0.75 barg vacuum and mesophilic temperature conditions. The mechanical stirrer in digester homogenized substrate medium. The digestion period lasted 40 days. The percentage composition of dry matter, organic matter, humidity, ash, carbon and nitrogen of the feed and digested were measured. Produced biogas analyzed by gas chromatography. According to the results, produced biogas and methane volume respectively at 3rd test compare to 1st test increased 15.52% and 21.31% and 3rd test compare to 2nd test 19.52% and 2.3 times. Vice versa, produced biogas and methane volume respectively at 2nd test compare to 1st test decreased 3.32% and 63.7%. Sodium hydroxide solution destroys hard tissue of cellulose lignin and hydrolyzes organic polymers. However, in high concentrations acetogenic and methanogenic microorganisms are inhibited by produced volatile fatty acids and saponification.
- Diffusion coefficient of ethylene in NMP using pressure decay method:
Experimental and modelling study
Abstract: The pressure decay of ethylene due to diffusion into the stagnant liquid of N-methyl-2-pyrrolidone (NMP) is evaluated at temperatures of 278.15, 298.15, and 328.15 K, and at three initial pressures of about 0.6, 0.8, and 1.1 MPa. Then, an available graphical method named initial model is implemented to calculate the diffusion coefficient. Some corrections on the initial model are applied as follows: 1) in the infinite series of the solution to the Fick’s second law, more terms are considered. 2) the equilibrium pressure is considered as a tuning parameter to eliminate the requirement for an inaccurate experimental measurement. The proposed model is proven to be more reliable and valid for a whole range of pressure decay data including the early times. Due to the large differences between the results of the initial and the proposed models, the Wilke-Chang relation is considered as a basis for comparison. This comparative study shows that results of Wilke-Chang relation is more compatible with the proposed model.
- Origin and Risk Assessment, and Evaluation of Heavy Metal Pollution in the
Soil of Tehran, Iran
Abstract: In this research, the concentrations of several heavy metals such as chromium (Cr), arsenic (As), nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), and cadmium (Cd) were measured using enrichment factor (EF), chemical separation, pollution index (Ipoll), ecological risk index (RI), and health risk assessments. The results of the soil EF showed that Cr, As, Ni, Zn, and Cu are at a minimum limit of pollution while Pb is at a moderate limit of pollution, and Cd has a significant level of pollution in the soil. The results of the chemical separation of anthropogenic and lithogenous phases demonstrated that the studied elements were of low pollution, except Cd. Based on Ipoll results, all metals were in the non-pollution zone except for Cd.The ER results of the metals in the soil of all metals were low except for Cd. According to USEPA guidelines, the risk of cancer from As, Ni, and Cr metals is high; the risk of Pb is medium; and the risk of Cd is low. The total risk of 9.68E-03 is unacceptable in the risk range because inhalation, ingestion, and skin contact with heavy metals increase cancer risk. During their average life expectancy of 70 years, 3,739 people develop various types of cancer. All metals’ hazard quotient (HQ) is lower than the safe level one in the non-cancer risk assessment. Even so, the total hazard index (HI) of 1.52E + 00 is more than 1, indicating that people are exposed to a variety of non-cancerous diseases due to breathing, swallowing, or skin contact with these metals. Eventually, Monte Carlo simulation uncertainty results support the results of cancer and non-cancer risk analysis. Overall, it is concluded that proper management strategies are required to control the concentration of these pollutants in Tehran’s soil to maintain the health of Tehran’s citizens.
- Optimization of Extraction of Flavonoid, Total Phenolic, Antioxidant, and
Antimicrobial Compounds from Ganoderma Lucidum by Maceration Method
Abstract: Plants are a rich source of phenolic and flavonoid compounds which are among the most important natural antioxidants. The aim of this study was to optimize the extraction of flavonoid, total phenolic, antioxidant and antimicrobial compounds from Ganoderma (G) Lucidum by the maceration method. To do so, independent variables including temperature, extraction time, and type of solvent along with Box-Behnken Response Surface Methodology (RSM) were used. The results of single optimization of the independent variables showed the highest flavonoid content (15.19 mg/g) with 100% desirability at extraction time of 48 h, the temperature of 60 °C by using ethanol solvent. The highest total phenolic content (16.96 mg/g) with 99.96% desirability was observed at extraction time of 26 h, temperature of 60 °C by using ethanol solvent. The highest amount of antioxidant compounds (3.03 mg/g) or the lowest IC50 value (mg/ml) with 100% desirability was found at extraction time of 48 h, temperature of 60 °C by using ethanol solvent. The results of simultaneous optimization of the extraction conditions by maceration method showed the highest flavonoid content (15.20 mg/g), total phenolic content (16.01 mg/g), and the lowest IC50 (3.03 mg/ml) with 98.157% desirability at extraction time of 48 h, the temperature of 60 °C using ethanol solvent. The highest mean Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of G. lucidum extract obtained by the maceration method were 2500 and 5000 μg/mL, respectively against Clostridium perfringens and Escherichia E. coli. The predicted optimized treatment had superior antimicrobial activity against Staphylococcus aureus with a non-growth halo (Zone of inhibition) diameter of 10.60 mm as compared to C. perfringens and E. coli. The results revealed that the G. lucidum extract obtained by the maceration method could be introduced as an antioxidant and antimicrobial source in marketable food products.
- Numerical Simulation of Low-Pressure Drop Static Mixers for Mixing
Enhancement
Abstract: Static mixers (SM), also generally known as inline mixers, form a newly developing industry trend. They have no moving parts, hence have lower energy consumption, lower installation cost, and very low maintenance cost, and are thus an attractive alternative to the conventional agitators. Modifications were made in the design to reduce pressure drop and increase the mixing intensity across the mixer and increase the application of inline mixers in the industries. Three hybrid geometries (different combinations of Kenics and LPD) of static mixers were constructed and simulated using computational fluid dynamics (CFD) tools. Kenics is an excellent radial mixing device, and low-pressure drop (LPD) an excellent axial mixing device. The key design parameter to modify LPD was the slope angle of elliptical plates which affects the mixer performance. Different slope angles from 90º to 120º were simulated. Kenics was modified for different aspect ratios, and the edge of Kenics was curved. Pressure drop, thermal, and Discrete Phase Model (DPM) analysis were performed on these three different classifications of hybrid geometries. The most promising geometry to emerge based on the low-pressure drop and good mixing efficiency both was the curved edge Kenics. Keen-sighted these results, further analysis was performed on curved edge Kenics after the modification of blend radius. It was concluded that for a lower Reynold number, the curved edge with a higher blend radius dominates all other mixers. Result validation was done by comparing the trends and sensitivity of process variables with the established results and standards.
- Experimental and Numerical investigation of implementing a novel vortex
generator: A Perforated Delta Wing Vortex Generator (PDWVG) on the
performance of Solar Air Collector
Abstract: Experiments were carried out for the numerical investigation of heat transfer enhancement in a solar air collector using different types of baffles and vortex generators. In this study, the vortex generator was implemented to increase the efficiency of the solar air collector. The variations in Nusselt number, pressure drop, friction coefficient, thermal and exergy efficiency in four collectors with different baffles arrangement (type A, B, C, D) were investigated. Type A was chosen as the optimum collector for implementing the vortex generator on the absorber surface. In the solar air collector the effects of using a novel vortex generator - the Perforated Delta Wing Vortex Generator (PDWVG), in comparison with a flat one - the Flat Delta Wing Vortex Generator (FDWVG), were considered. In order to determine the maximum efficiency of the solar air collector, four different pitch ratios of vortex generators were studied. The Nusselt number and pressure drop increased with Reynolds number but the friction coefficient decreased with Reynolds; the experimental and numerical results revealed that the thermal and exergy efficiency decreased from a specific range. The comparison of PDWVG and FDWVG showed that presence of holes on the novel vortex generator, led to reduced pressure drop and increased the heat transfer between the air flow and the absorber surface. Increasing the number of vortex generator rows had a slight effect on increasing the studied parameters. The results showed that collector type A with ep=0.55 of PDWVG improves the energy and exergy efficiency 4.43% and 5.29% respectively.
- SPH modeling and investigation of the shear and blender mixers for mixing
cement paste
Abstract: Mixing and homogenization of cement paste are some of the most used phenomena in construction and building industries. In most cases, a homogeneous mixture of cement paste is required and this is supplied by rotary mixers. In the present study, the rotary cement paste mixers in two-dimensional (2D) conditions are investigated by an Incompressible Smoothed Particle Hydrodynamics method (ISPH). The method is validated and then is used to model the cement paste mixer. The cement paste is considered as a Bingham fluid. Two types of mixers are examined; shear mixer and blender. An appropriate mixing index that was previously applied to the discrete element method was successfully implemented for the ISPH method, and the performance of these two types of mixers is analyzed with this mixing index. The results show that the Reynolds number has a key role in the mixing in the shear mixers. In the low Reynolds numbers, an unmixed region is formed, which decreases with increasing Reynolds number. In blender mixers, the mixing rate is expected to increase with the multiplicity of vortices formed. But the coordinated motion of the vortices with the blades causes a fluid mass to move. Also, the resistance of the fluid to the moving components of the mixer is calculated and the difference in the performance of the two mixers in terms of energy consumption and mixing speed is compared and discussed.
- Investigation of Thermal Conductivity and Convective Heat Transfer
Coefficient of Water-based ZnO Nanofluids
Abstract: Nanofluids are stable suspensions of nanoparticles in a conventional fluid. They have shown superior potential in heat transfer enhancement. In this research, ZnO/water nanofluids were prepared at various concentrations from 0.2 to 1.5vol%, and their thermal conductivity was measured. The results showed that the thermal conductivity of ZnO/water nanofluids depends on particle concentration and increases non-linearly with the volume fraction of nanoparticles. The effects of particles size and temperature on the thermal conductivity were also investigated at 1.5vol%. The results indicated that thermal conductivity enhanced with decreasing particles size and increasing with temperature. For nanofluids containing 10-15 nm and 45-50 nm particle sizes, the enhancements were 26.3 and 22.8% at 40oC, respectively. In this research, the convective heat transfer coefficient of ZnO/water nanofluids with the above particle sizes was also measured under laminar flow in a horizontal tube heat exchanger. It was observed that both nanofluids showed higher heat transfer coefficients compared to the base fluid at a constant concentration (1.5 vol%). For nanofluids with 10-15 nm and 45-50 nm particle sizes, the average heat transfer coefficient enhancement was 18.1 and 14.9% at Re=1115, respectively.
- Optimizing the overall heat transfer coefficient of a spiral plate heat
exchanger using gams
Abstract: Spiral plate heat exchangers should be efficient devices because they are widely employed in the petrochemical and food industries; furthermore, their operation has a direct impact on electricity consumption in such sectors. For those reasons, this article aims to improve the efficiency of heat exchangers by means of optimization techniques. Using as objective function the maximization of the overall heat transfer coefficient of a spiral plate heat exchanger. The mathematical formulation includes several variables in the problem: width, length, spacing between the plates, and plate thickness. And as a set of constraints the heat duty and the pressure drop, along with technical considerations associated with this type of systems. The General Algebraic Modelling System (GAMS) was purposed as a solution method and compared with the Particle Swarm Optimization (PSO) algorithm, a Genetic Algorithm (GA), the original design proposed by Minton and the Tuned Wind-Driven Optimizer (TWDO). Results show that the purposed method obtains the highest value of objective function being 1.5% better than the best of the used comparison methods with a computing time of 1e-4s, finding a solution with high quality at a low computational cost.
- Multiple Objective Optimization of Industrial Naphtha Cracking Process by
Box-Behnken Response Surface Methodology
Abstract: Naphtha in presence of steam is cracked to produce ethylene, propylene, and 1,3-butadiene which are important feedstocks in the petrochemical industry. It is important to optimize industrial process conditions to maximize the yield of 16 desired products individually as well as a combination of those based on the market demand. The parameters influencing the naphtha cracking product yield are feed composition, coil-outlet temperature (COT), coil-inlet pressure, residence time/feed flow rate, and steam to hydrocarbon feed ratio (SHFR). In this research, Box-Behnken response surface design has been used to evaluate the effects and interactions among three factors such as COT, SHFR, feed flow rate on product yields by carrying out 15 experimental test runs. The SHFR, COT, flow rates were varied in the range from 0.38−0.5, 810−824 °C, 14.8−17.2 tons per hour (tph), respectively. Models for three different naphtha feeds having different heavier hydrocarbon content (C8+) have been developed. Another model has been developed considering 27 experimental test runs with C8+ composition (3.74 wt.%, 6.81 wt.%, and 9.88 wt.% ) as the fourth factor. These model results have been validated with Industrial process data on ethylene and propylene yields for ten case studies. The model predicted yields match excellently well with that of industrial reactor yield. Response optimizer has been developed to optimize process conditions to maximize yields of ethylene, propylene separately, and also combined yield of ethylene+propylene+1,3-butadiene. It has been found that the higher COT has a favorable impact on Ethylene and 1,3-Butadiene yield. The Increased C8+ content results in a lower yield of Ethylene, Propylene, and 1,3-Butadiene. Increased SHFR and feed flow rate reduces the Ethylene yield. The optimized condition has been reported. The optimum was found at COT of 824°C, SHFR of 0.4919 kg-steam/kg-naphtha, the flow of 14.8 tph, and C8+ content in a feed of 3.74 wt.%.
- Model-Based Scheduling of Smart Injection and Production Wells for
Waterflooding in Multi-Layer Reservoirs
Abstract: Smart wells are unique tools for management of oil reservoirs under waterflooding to increase the oil flow rate and reduce the associated wastewater production costs. The costs associated with smart completion are considerable. Consequently, the decision for designing and controlling such completion elements can have considerable impacts on project profitability.This work presents an efficient production scheduling for a multi-layer reservoir during water-flooding by regulating water movement in the layers to control associated wastewater using smart elements. The central focus in this research is to give a production schedule using smart well completions. To achieve this, several segments of the production and injection wells are controlled independently with the schedules provided by a model-based optimization technique. To perform optimization, three methods are used to regulate waterfront and velocity in different layers; the first approach is used to regulate production well according to the saturation distribution in the reservoir without considering NPV. The second approach is sequential optimization of well controls including flow rates and bottom-hole pressures, to find an optimized NPV. The third approach is to optimize flow rates and bottom-hole pressures for different segments in the production and injection wells, simultaneously, to achieve a maximized NPV using a genetic optimization algorithm. To evaluate these approaches, 2D and 3D reservoir models are used as case studies. The study shows a considerable increase in NPV with respect to conventional wells in a fair comparison ground. In 2D model, 9.89%, 11.75% and 11.78% additional recoveries are achieved compared to a conventional production well using the first, second and third optimization approaches, respectively. For 3D model, 5.87%, 5.99% and 6.20% were additional recoveries with reference to the equivalent conventional production wells, for the first, second and third approaches, respectively. This additional recovery is due to lower produced associated water and bypassed oil.
- Evaluating the amount of exposure to benzene by urinary trans-trans
muconic acid levels assessment for workers in contact with volatile
organic compounds (VOCs)
Abstract: Benzene is one of the major constituents of the volatile organic pollutants family and one of the major pollutants in air pollution, which contains the most extensive chemical compound used in both natural processes and synthetic processes. The main way to contact benzene in the industry is through the respiratory tract. Exposure to benzene can cause many of the most dangerous adverse health effects, especially leukemia. The purpose of this study was to use high performance liquid chromatography analysis technique to determine the exposure level of benzene dyeing plant workers and the bioassay of trans-trans muconic acid in urine. This is a case-control study. 65 painting factory workers (in two groups exposed to benzene and not exposed to masks and without respiratory masks) participated in this study. Samples were collected at the beginning and end of the shift. High performance liquid chromatography (HPLC) was used to determine the concentration of trans-trans muconic acid in urine samples. The results showed that the mean concentration of trans-trans muconic acid as a metabolite of benzene in the urine of exposed workers (mean ± standard deviation) was 2.7025± 3.18126 (ppm) and the mean concentration of trans-trans muconic acid in workers with mask (mean ± standard deviation) is 1.4079±2.73664 (ppm). Statistical analysis of the results between the two groups showed that the exposure to benzene concentration between workers with and without respiratory masks was (p=0.246) and was P> 0.05. Consequently, there was no significant difference between the two groups. The present study shows that the average concentration of transmuconic acid in workers' urine indicates exposure to higher concentrations than standard benzene, so it can be said that these people are at risk for occupational diseases, occupational cancers and other side effects. are. From exposure to these pollutants.
- Investigation of flutamide@ethyleneimine as drug carrier by nanocone and
nanotube theoritically
Abstract: Flutamide is used together with a luteinizing hormone-releasing hormone agonist, a type of hormonal injection such as leuprolide, goserelin or triptorelin to treat certain types of prostate cancer. Flutamide is in a class of medications called nonsteroidal antiandrogens. Ethyleneimine is used in polymerization products; as a monomer for polyethyleneimine; as a comonomer for polymers and in paper and textile chemicals, adhesives, and binders .In this study applied ethyleneimine to modified the Flutamide as anti-cancer drug. Therefore, investigation of the adsorption behavior and electronic properties of carbon nanotubes and nanocones against flutamide @ ethyleneimine was carried out by calculation of the density functional theory. The N atom of flutamide @ ethyleneimine helps its adsorption on the nanotubes and nanocones, showing adsorption energies of around - 30.1 and - 20.5 kcal/mol, correspondingly. Chemical activities of the nano complexes were specified through electronics parameters such as electronegativity, electro affinity, softness and hardness. All calculated data obtained good behavior of flutamide @ ethyleneimine with nanotubes and nanocones adsorption as carrier.
- Immobilization of pectinase enzyme on hydrophilic silica aerogel and its
magnetic nanocomposite
Abstract: In this work, Aspergillus niger pectinase was immobilized on hydrophilic silica aerogel and its magnetic nanocomposite by adsorption method, and the performance of these supports in pectinase immobilization was compared. Physical and chemical properties of supports and the immobilized pectinase were characterized by Brunauer–Emmett–Teller (BET) analysis, field emission scanning electron microscope (FESEM), Fourier transforms infrared spectroscopy (FT-IR), and vibrating sample magnetometer (VSM). The results showed that the pectinase was successfully immobilized onto both supports. The kinetics of the immobilized pectinase followed Michaelis–Menten model. The maximum reaction rate (Vmax) and affinity of immobilized pectinase to the substrate (Km) in pure silica aerogel were higher than magnetic silica aerogel. The maximum monolayer adsorption capacity of the pure silica aerogel (qmax=129.17 mg g-1) was higher than magnetic silica aerogel (qmax=53.42 mg g-1) based on Langmuir isotherm. The thermal stability of the immobilized pectinase was improved toward free pectinase. The reusability tests of immobilized pectinase showed that magnetic silica aerogel had better operational stability than pure silica aerogel because of higher mechanical resistance and retained 57% of its initial activity after 10 repetitive cycles.
- Ni /Fe3O4@nanocellulose and Ni/nanocellulose green nanocomposites:
Inorganic- organic hybrid catalysts for the reduction of organic
pollutants
Abstract: In this work, Ni NPs have been in-situ synthesized using hydrazine as a reducing agent and immobilized on nanofibrillated cellulose (Ni/NFC) and magnetic nanofibrillated cellulose (Ni/Fe3O4@NFC) as green supports. The structure and morphology of the Ni/Fe3O4@NFC nanocomposite clarified high purity single-phase spherical-shaped Ni nanoparticles of about 30 nm distributed on the surface of nanocellulose as compared to the larger size of star shape particle in Ni/NFC. The catalytic activity of both nanocomposites was investigated for the reduction of 4-nitrophenol (4-NP), methyl orange (MO), and methylene blue (MB). The results demonstrated high catalytic efficiency towards the removal of water pollutants in a short reaction time. The reduction rate constants (k) of freeze-dried Ni/Fe3O4@NFC catalyst were 30 ×10-3 1/s, 17.3×10-3 1/s, and 6.9 ×10-3 1/s, for 4-NP, MO, and MB respectively, which were higher than those of synthesized Ni/NFC and other reported Ni-based catalysts. Moreover, the catalyst could be easily magnetically recoverable and reusable in other cycles.
- Graphene quantum dots modified with metformin/Co(II) as efficient
oxidation catalyst
Abstract: While one of the valuable approaches to obtain a heterogeneous catalyst is the supporting them on a high surface area supports, strategy mainly suffers from the low number of chelating agents on most of the supports to grip the metal cations catalysts. Therefore, loading multidentate compounds susceptible to bind with metal cations is a potent strategy to improve the catalyst stability on the support. In this report, metformin as a multi-dentate ligand was bonded onto graphene quantum dots as a high aspect ratio compound to afford a new support susceptible for chelating Co(II). Deposition of Co(II) on graphene quantum dots modified with metformin gave a new sustainable heterogeneous catalyst that was highly active in the oxidation of alkyl arenes. The reactions were performed in solvent-free conditions at 80 ºC with high conversions up to 96%. The organometallic compound is applicable as a recoverable heterogeneous catalyst with recyclability up to 6 times. The modification of graphene quantum dot with metformin also can be gains more attentions of medicinal researchers.
- Hg(II) complexes constructed from indazole ligands as new heterogeneous
catalyst for the Biginelli/Transesterification reaction: Synthesis and
quantum-chemical investigations
Abstract: The present work deals with the synthesis, spectral characterization, DFT calculations and catalytic activity of the new Hg(II) complexes derived from indazole ligands. The o-amino-ketones were obtained from the reduction of 6H-isoxazolo[4,3-e]indazoles as new heterocyclic ligands. Coordination of the ligands to Hg(II) cation led to the formation of new Hg(II) complexes. The IR, mass, and NMR spectra as well as the elemental analyses confirmed the structures of the new complexes. Furthermore, the DFT calculations at the B3LYP/6-311+G(d,p) level were used to gain further insight into the geometry of Hg(II) complexes. The catalytic activity of Hg(II) complexes as heterogeneous catalysts were studied for the synthesis of biologically active 3,4-dihydropyrimidin-2(1H)-one C5 ester (DHPMs), using classical Biginelli reaction followed by transesterification transformation. The results showed that the current procedure gave the products good to excellent yields at reduced reaction time, which might be owing to the increased reactivity of the reactants on surface area of Hg(II) complexes.
- Experimental and Theoretical Studies of New Schiff Base as a Corrosion
Inhibitor in Acidic Media and Study Antioxidant Activity
Abstract: In the present, the synthetic of 1,1'-((1E,1'E)-((4,5-dimethyl-1,2-phenylene)bis(azanylylidene))bis(methanylylidene))bis (naphthalen-2-ol)was investigated. The product was synthesized through the reaction of 2-hydroxy-1-naphtha-aldehyde with, 4,5-Dimetyl-1,2-penylenediamine for 4h. The achieved yield was 90.09%. The prepared compound was identified by C.H.N, UV-Vis, FTIR 1H–NMR, mass spectroscopy and was studied also theoretically using Gaussian 09 software based on the DFT method at B3LYP/6-31G (d,p). Quantum chemical calculations were performed to provide further insight into the inhibition efficiencies that conducted experimentally. The weight loss method was used to evaluate the efficiency of the prepared compound as a corrosion inhibitor in an acid medium. It was found that the inhibition efficiency was increased with the concentration increase of synthesized Schiff base. Furthermore, the effect of temperature variation on the corrosion rate was studied. It was found that the adsorption process of the inhibitor on the surface of the brass is obeyed to the Langmuir isotherm of adsorption. The value of the free energy change also indicated that the prepared compound adsorbed the surface of the metal by means of physical and chemical interferences. The antioxidant activity of the phenolic Schiff base was investigated on the basis of the radical scavenging effect of 1,1-diphenyl-2-picryl-hydrazyl (DPPH)-free radical activity was also studied. The ligand (S1) exhibited excellent activity.
- REDUCING THE AMOUNT OF BORON IN THE WASTEWATER OF A BORON PROCESSING PLANT
BY CHEMICAL PRECIPITATION
Abstract: The effect of pH and the amount of Ca(OH)2 on the precipitation of boron from Eti Maden Kırka Boron Operations’ wastewater that contained 2752 ppm boron was investigated. It was observed that control of pH was the most important parameter and stepwise addition of Ca(OH)2 after adjustment of pH improved the precipitation. Best result was obtained in two stage addition of Ca(OH)2 with initial control of pH and additional use of aluminum sulphate in the second stage that helped both in the reduction of pH and coagulation. Under these conditions, it was possible to lower the boron content in the wastewater to 250 ppm.
- Adsorption of Hg2+ onto Novel Mesocellular Foams Silica Functionalized
with Disodium Ethylenediaminetetraacetate: Thermodynamics, Isotherm, and
Kinetics Studies
Abstract: Mercury is one of the most important heavy metal elements of environmental pollution, and it is very important for its control. Mesocellular Foams (MCF) silica was prepared by hydrothermal method, and the prepared material was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), 77 K low temperature nitrogen gas adsorption-desorption. Herein, the authors aimed to improve the adsorptive performance of MCF against mercury ion through a functionalization using disodium ethylenediaminetetraacetate (EDTA-Na2). Our novel material, was then used in the batch adsorption of Hg2+, where the maximum conditions were reached after 35-minutes contact time at pH 3 with adsorbent weight of 0.1 g. The maximum adsorption amount of Hg2+ in aqueous phase was 139.64 mg Hg2+ / g (modified MCF). The maximum desorption ratio of Hg2+ was 75.23% achieved by using 0.1 mol/L hydrochloric acid solution. Process for the adsorption of Hg2+ conforms to the quasi-second-order adsorption kinetics and Langmuir adsorption isotherm. The results of the low-temperature N2 adsorption-desorption curve at 77 K showed that Hg2 + had entered the MCF pore channels. This novel material is effective in removing Hg2+ from water medium via batch adsorption.
- Prebiotic Synthesis of Sugar and Molecular Dynamic Simulation of
2,3-Dihydroxypropanal Adsorption on Montmorillonite
Abstract: This study initially investigated sugar production through Formose reaction (FR) using methanol as solvent and an aerosil (fumed silica) as catalyst. The products observed in the reaction medium were 2,3-dihydroxypropanal (glyceraldehyde) and 1,2-ethanediol (ethylene glycol). The results showed that if the target of the reaction is to produce glyceraldehyde (GA) and ethylene glycol (EG), the aerosil is a better option as catalyst in the FR. Finally, molecular dynamic (MD) simulation of 2,3-dihydroxypropanal adsorption was investigated on montmorillonite (MMT) as a mineral adsorbent. MD simulation indicated that the adsorption of GA molecule at the MMT-water interface occurred due to the oxygen of carbonyl group. The radial distribution function (RDF) of the solvent around the main atoms of GA and the root-mean-square deviation (RMSD) were calculated from the MD simulation results using Gaussian and LAMMPS software. The RDF results showed a weak hydrogen bond between oxygen atoms of the hydroxyl group and solvent molecules. Moreover, the solvent molecules had no significant influence on the behavior of tetrahedral carbons of GA, indicating that the oxygen atom of the carbonyl group had a higher ability to form a hydrogen bond with water compared to the other atoms. The RMSD of carbonyl oxygen, carbonyl carbon, hydroxyl oxygen, and tetrahedral carbon increased during a simulation time of 20 ns, respectively. Evaluation of mean distance of calcium atom at the surface of MMT and different atoms of GA showed that the GA molecule was chemically adsorbed on the surface of MMT by oxygen of carbonyl. The mean distances of C-tetrahedral, C-carbonyl, O-hydroxyl, and O-carbonyl in the GA structure from the surface of MMT (distance from calcium ions) were estimated to be 3.8, 3.2, 3.0, and 2.6 Å, respectively.
- Extraction and Physicochemical Characterization of Chitosan from
Litopenaeus vannamei Shells
Abstract: The chitosan was extracted from whiteleg shrimp shell (Litopenaeus vannamei (by the deacetylation of chitin, which is carried out using 45% NaOH at 110 ºC for 6 h. The prepared chitosan was characterized by using the Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDXS), and Thermogravimetric analysis (TGA). The physicochemical property of this extracted polysaccharide, including the degree of deacetylation, apparent viscosity, molecular weight, water binding capacity (WBC), and fat binding capacity (FBC) from whiteleg shrimp shell was evaluated. The current study contrasted the characteristics of chitosan with commercial type. Accordingly, to obtain the degree of deacetylation, the titration method and elemental analysis were considered, while the viscometric methods were used to achieve the molecular weight. The SPSS software was used for the analysis of the obtained data. Based on the comparison between the studied chitosan and commercial one, some behaviors were observed, including increased deacetylation and viscosity, decreased molecular weight, and higher water and fat binding capacities. The degree of deacetylation was determined as 86% for the titration method and 83% for elemental analysis. WBC and FBC of chitosan from shrimp were reported as 673.58 and 491.32, showing that all chitosan properties experienced a good improvement compared with the commercial type.
- Simultaneous Extraction and Stripping of Methylene Blue: A Liquid-Liquid
Extraction and Bulk Liquid Membrane Approach
Abstract: In this study, the Liquid-Liquid Extraction (LLE) method was used to demonstrate the extraction of Methylene Blue (MB) from aqueous solutions using 4.48×10-1 mol/L Phenyl Propiolic acid benzene. The operating parameters like the changes brought by varying pH (liquefied solution pH), diluents, concentration of extractant, and stripping reagents were evaluated with fixed reaction conditions. A maximum recovery of MB was obtained at pH 7±0.1. Similarly, the maximum stripping efficiency of MB was achieved by the use of 1 N H2SO4. The optimized parameter obtained for the recovery of MB from the LLE process was implemented in the bulk liquid membrane (BLM) technique. The separation and procurement of MB were performed in a single step is called the pertraction process. The role of pH in the aqueous donor phase, the effect of phenyl propiolic acid concentration in the membrane phase, and the effect of stripping reagents concentration were evaluated in detail to understand the transport mechanism of MB from the aqueous phase to interface and interface to stripping solution.
- Evaluation of the Physicochemical Properties and Aflatoxin Levels of
Industrial and Non-industrial Sesame Oil
Abstract: ABSTRACT The present study aimed to evaluate the physicochemical properties and level of aflatoxins (AFB1, AFB2, AFG1 and AFG2) in the sesame oils (cold press) consumed in Iran. In total, 30 sesame oil samples were collected from factories (n=20; industrial) and traditional mills (n=10; non-industrial). No significant differences were observed between the industrial and non-industrial sesame oil samples in terms of the physicochemical properties and AF contamination and therefore, it is not possible to prefer consumption one of oils (industrial or non-industrial) to another. According to the physicochemical examination, the mean of peroxide value was 2.93±1.59 and 1.95±1.24 meq/kg, the acid value was 0.86±0.82 and 1.12±0.58 mg KOH/g, the refractive index was 1.4,706±0.0002 and 1.4,705±0.0001 at 28°C, and the conjugated diene value was 12.13±3.25 and 10.02±1.43 μmol/g in the industrial and non-industrial sesame oil, respectively. In addition, the fatty acid profile of the industrial and non-industrial sesame oil indicated high levels of unsaturated fatty acids (84.5% and 83.49%, respectively), with the main fatty acids determined to be oleic acid and linoleic acid. The fatty acid profile of the sesame oil samples indicated no adulteration with other vegetable oils. The mean contamination with AFB1, AFB2 and AFG1 in the non-industrial sesame oil was estimated at 0.06±0.26, 0.02±0.67, and 0.15±0.18 µg/kg, while the mean contamination with AFB1, AFB2, and AFG1 was 0.04±0.84, 0.03±0.61, and 0.17±0.16 µg/kg in the industrial sesame oil. Moreover, the AFB1 and AFs levels in all the sesame oil samples were significantly lower than the Iranian legislation limits (5 and 15 µg/kg, respectively) and the European Union (2 and 4 µg/kg, respectively). Risk assessment based on the margin of exposure revealed the risk of AFB1 and AFG1 exposure through industrial and non-industrial sesame oil consumption and AFB2 exposure through industrial sesame oil consumption
- Experimental investigation and modeling the heat transfer coefficient in
the pool boiling: Bubble Dynamic and artificial intelligence
Abstract: In this work, the heat transfer coefficient in the pool boiling process was investigated for different alcoholic solutions. To exact evaluation, the bubble dynamic including bubble departure diameter, bubble departure frequency and active nucleation sites’ density were studied. The results showed that with increasing isopropanol concentration (20 V.% - 80V.%), bubble departure frequency and active nucleation sites increased while bubble departure diameter decreased. The bubble dynamic cannot be effective in any amount and must be optimized to reach an optimum heat transfer coefficient. Isopropanol concentration of 20 V.% was reported as an optimum state and lower decrease versus deionized water (11.892%). This result confirmed that the bubble departure diameter played a significant role in promoting the heat transfer coefficient. Finally, to predict the experimental data, a genetic algorithm (GA) based correlation (power-law function) was developed. The optimization procedure revealed that the GA model had a good agreement with the experimental data (R2=0.968, AAD= 0.0288). In addition, this approach was compared with conventional models (Palen, Stephan, Unal, Fujita and Inoue). The GA and the Stephan models presented the best and worst performance, respectively.
- A Hybrid Mathematical Programming Model for Densities of Alkanol +
Alkanediol Mixtures Using Bacterial Foraging Optimization Algorithm
Abstract: In this work, the densities of pure and binary mixtures of 1-pentanol or 1-decanol with 1,2-ethanediol or 1,2-propanediol or 1,3-butanediol or 2,3-butanediol were measured at atmospheric pressure and temperatures between 288.15K and 313.15K. For the considered system, two types of models were applied: black box and phenomenological. The black box model is represented by Artificial Neural Networks (ANNs) optimized with an improved version of Bacterial Foraging Optimization (iBFO). The phenomenological models are represented by Spencer-Danner and Li equations. In addition, in order to better fit the Spencer-Danner and Li equations to the obtained experimental data, the free parameters of these models were included into an iBFO algorithm. The average absolute error of the best ANN obtained was 2.82%, while for the new forms of the Spencer-Danner and Li equations had an improvement from 26.31% and 26.51% respectively to 3.51% and 4.01% respectively. These results indicate the flexibility and efficiency of iBFO, which is able to provide good solutions for a variety of cases
- Investigation of operating parameters’ effects on bubble
characteristics in a co-current downflow bubble column
Abstract: Bubble columns are frequently employed as multiphase reactors and gas-liquid contactors. In the bubble column, gas is dispersed into the liquid phase. The dispersion of gas into a liquid is the function of bubble size and its distribution. It also includes the complex process of coalescence and break up of bubbles. The present research work intends to examine the effect of operating parameters, including temperature on bubble characteristics in the ejector-induced downflow bubble column (i. d. 0.05 m X 1.6 m height) via Computational Fluid Dynamics (CFD) and experimental methods.Bubbles inside the column are analysed and mean bubble diameters are obtained using a photographic technique. The effect of superficial gas velocity (4.25×10−3-9.68×10−3 m/s) and liquid velocity (8.5×10−2-14.11×10−2 m/s) on an average sauter diameter is studied. The gas holdup variation with temperature (60-80 oC) is also examined. The temperature distribution at different axial locations (0.48-1.35 m) from the top of the column is observed using the CFD model. An empirical model for predicting the temperature, i.e., Tr (T/Tset), is proposed as a function of the Prandtl number, Weber number, Reynolds number, and Froude number.
- Separation of Zirconium and Hafnium from Chloride Solution using Strongly
Basic Anion Resins
Abstract: The ion exchange process was employed to separate zirconium from hafnium in solution. To this end, four effective parameters, involving resin type, HCl concentration, Time, and initial zirconium concentration, were selected as the main variables. The sorption of zirconium and hafnium in the presence of six commercial macroporous anion exchangers of Dowex and Amberlite series and different HCl concentrations of 8-12 M was investigated. Furthermore, the distribution ratio, as a function of time in the range of 0.5-3 h, and initial zirconium concentration of 500-3000 ppm, were studied. The highest separation factor of 10.29 was obtained under equilibrium conditions in the presence of Amberlit CG-400II ion exchange resin (IER) at a concentration of 9.5 M hydrochloric acid. Equilibrium isotherms of the system under optimized conditions were analyzed by Langmuir, Freundlich adsorption models. The experimental data are well-described by the Langmuir equation for both zirconium and hafnium.
- Feature extraction of contaminated oil signal based on HHT
Abstract: The movement state of contaminated oil in the pipeline is of great significance to the safe operation of oil-using equipment. And the dynamic motion characteristics of the oil can be characterized by signals. However, the pressure signal of the oil is time-varying and complex; hence it is a typically non-stationary nonlinear signal. Therefore, the traditional linear analysis method used for the analysis of the oil signal is not suitable. For this reason, the Hilbert-Huang Transform (HHT) method is used to process and analyze the differential pressure signals of oils with different degrees of pollution, to obtain the characteristic frequencies of oil pressure signals, to explore the intrinsic connection of the characteristic frequencies and oils with different degrees of pollution, and to reveal the dynamic movement characteristics of oil in the pipeline. The results show that the characteristic frequencies corresponding to the five groups of oil samples with a pollution degree of 17/12,18/12,19/13,19/13,20/16 (ISO4406 standard) are 20.29 Hz, 10.22 Hz, 6.94 Hz, 17.01 Hz, and 6.81 Hz, respectively; Each Intrinsic Mode Function (IMF) component of the oil signal has obvious frequency modulation characteristics; As the pollution degree increases, the oil frequency of the IMF2-4 component mainly shifts toward the middle of the interval, and the oil frequency of the IMF5-7 component mainly shifts toward the direction of 5.00 Hz, 3.00 Hz, and 1.60 Hz respectively.
- Textural Properties of Emulsion-Filled Gel Formulated with Oleogels as Oil
Fraction Using a Response Surface Methodology
Abstract: Looking for the development of new food ingredients, the Box-Behnken design was employed to determine the effect of two different oleogels, elaborated with a celluloses mixture or with candelilla wax, as oil fraction, on the textural properties of emulsion-filled gels with egg white as emulsify/gelling agent, at different ionic strength condition. Compression test parameters were determined on both samples (force, work, and modulus) to analyze the effect of the variables on texture. Emulsion-filled gels with candelilla wax oleogel resulted firmer and more difficult to compress, as compared to celluloses oleogel, with a less hard and softer texture. The increase in protein concentration resulted in a stiffer texture, but when the oil fraction (oleogel proportion) increases, the emulsion-filled gel texture turned more squishable. No major effect was observed by the employed ionic strength conditions. The model predictions for textural parameters in both samples were closely correlated to the experimental results obtained. The use of different ingredients that can be employed as oil fraction with different textures that can be manipulated, distinct oleogel formulations -as the type of organogelator agent, type of edible oil- allows designing textural and thermal properties of emulsion-filled gels, with great potential as fat replacers in processed foods.
- Investigating the Effect of Temperature, Molar Ratio of Ethylene Glycol to
Oil, and Catalyst Amount on Production Yield Bio Lube from Neem Seed Oil
Abstract: Excessive use of petroleum-based lubricants and their hazardous disposal has increased environmental pollution; hence the need for eco-friendly lubricants has been increased to meet the requirement of industry and automotive. Due to the oil crisis, the world’s attention has been diverted to producing bio-lubricants from non-edible sources. This study discusses the effect of various parameters on transesterification reaction to produce bio lubricant from Neem oil. The dried neem seeds were crushed, and the oil was extracted using the Soxhlet extraction method using n-hexane. The bio lube was produced by a double transesterification process using CaO as a catalyst. The effect of temperature, molar ratio, and catalyst wt% on yield bio lubricant was observed. The temperature varied from 110 to 140 °C, molar ratios varied from 2:1 to 8:1, and the catalyst wt% was 0.8 to 1.6%, keeping the reaction time and other conditions constant. During the experimentation, it was observed that the yield was low at 110°C, but as the temperature increases, yield also increases, but no significant change in yield was observed beyond 130°C. The maximum yield observed at 130°C, and 140°C was 93.7% and 94.37%, respectively. Similarly, as the molar ratio increases, the yield of bio lube also increases, and the maximum conversion was 94.3% achieved at molar ratio 8:1, but molar ratio 6:1 may be considered as optimum because there is no substantial increase in conversion after 8:1. Moreover,the profile was observed by varying the amount of catalyst and it is evident from the results , as the amount of catalyst increases as the conversion increases from 66% to 95%; however, at a catalyst ratio of 1.6 wt %, a yield was decreased slightly to 94.2. It has been observed that the temperature has a significant impact on the yield of Biolube.
- Bio-scrubber performance equipped with Airlift parallel bioreactors
(APB’s) for BTX bio-degradation by wastewater sludge
Abstract: A new approach in this work was biodegradation of benzene, toluene and xylene (BTX) using airlift parallel bioreactors (APB’s) connected to the Plexiglas bio-scrubber (PBS) modulated with polyurethane foam (MPF) as modified sort in the use of mineral pumice as a porous filler Lava rock media. The aeration bioreactors were set up with a microbial consortium of refinery sludge effluent sewer (SES) treatment and nutrient solution. The performance of PBS for BTX removing by APB’s filled with activated sludge effluent sewer (ASES) in the range of inlet BTX concentrations from 180.7 to 881.8 ppmv in different air pollutions flow rate was tried for two rates: 2.5 & 3.5 lit/min at 30 days mean residence time distribution (MRTD) for each treatment. The results showed that at inlet pollutant concentrations of [B] = 180.7 ppmv, [T] = 327.4 ppmv & [X] = 297.5 ppmv, the removal efficiency in flow rate 2.5 lit/min was 90.7, 88 and 83.6(%) for benzene, toluene and xylene, respectively. The amount of removal in flow rate 2.5 lit/min was better than removal efficiency in 3.5 lit/min due to lower pollution concentration.
- Effect of SiO2 nanoparticles on thermal properties of polyaniline/
palmitic acid composite as an energy storage system
Abstract: Phase change materials (PCMs) can be used as thermal energy storage systems in the form of latent heat. These materials are commonly enclosed in a suitable container, in order to prevent leakage of the molten PCM into the surrounding environment. In this study, palmitic acid and polyaniline were used as PCM and polymeric shell, respectively, to prepare a form stable composite. SiO2 nanoparticle was added to the composite to improve thermal characteristics of the composite. The structure and morphology of the prepared form stable nanocomposite were investigated by Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and X-ray diffract meter (XRD) tests. It was found that the synthesized nanocomposite was fabricated in the form of relatively smooth and compact spherical particles with a size of about 500 nm. Thermal properties of the prepared nanocomposite containing different concentrations of SiO2 nanoparticles were determined using differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA) tests. It was found that the melting temperature and thermal conductivity of the polyaniline/palmitic acid composite increased by about 16% and 62%, respectively, when combined with 2 wt.% SiO2 nanoparticles. The obtained results revealed that the polyaniline/palmitic acid/2 wt.% SiO2 nanocomposite can be considered as a suitable option for thermal energy storage applications.
- Effect of membrane clarification on the physicochemical properties of
fruit juices: a review
Abstract: Fruit juices are important drinks, which are a rich source of water, vitamins, minerals and other nutrients. Juice processing can affect its physicochemical properties and, therefore, change its nutrient value. One of the most important processes in juices is their clarification and concentration. Today, membrane processes such as microfiltration, ultrafiltration, nanofiltration, electrodialysis, membrane distillation and osmotic distillation are used as a new method for concentration and clarifying juices. The application of membrane processing has a significant effect on the physicochemical properties of juices such as pH, total solids, color, acidity, vitamins and minerals, phenolic compounds and antioxidant activity. In this review, the effect of several membrane separation methods (microfiltration, ultrafiltration, nanofiltration, electrodialysis) on physicochemical properties of fruit juices will be evaluated. Some membrane processes increase the pH of the juice and some do not change this parameter. The membrane clarification process reduces the total soluble solid (TSS), turbidity, polyphenols and antioxidant activity of fruit juices with different values. In addition, this process can completely remove the suspended solids from fruit juices. Most researchers have suggested that membrane clarification enhances the color value of juices. The effect of membrane processes on the amount of organic acids and minerals depends on the type of juice, the type of membrane process and the type of acid and mineral.
- Adsorption of Nickel (II) from Aqueous Solution using Leucaena
leucocephala Shells
Abstract: Water pollution, as a result of industrial development, has detrimental effects on aquatic organisms and human beings. In this research, Leucaena leucocephala biomass was modified using Fenton’s reagent and sodium hydroxide and the performances of the native, Fenton-treated and NaOH-activated adsorbents for removal of Ni(II) from aqueous solution were evaluated under various experimental conditions such as initial pH, contact time, initial concentration of Ni(II), adsorbent dosage, and temperature. The adsorbents were characterized using Fourier transform infrared spectroscopy and pH of point of zero charge. Kinetic and equilibrium adsorption data were well described by Elovich and Liu models, respectively. The maximum adsorption capacities are 50.66, 56.72 and 75.17 mg/g for the native, Fenton-treated and NaOH-activated L. leucocephala adsorbents, respectively. Desorption of Ni(II) from the surface of the adsorbents was done effectively with 0.03 mol/L of hydrochloric acid. Thermodynamic calculations show that the adsorption process was spontaneous, feasible and favourable because the values of ΔGo were negative. Adsorption of Ni(II) onto the adsorbents was exothermic (ΔHo values were negative) and there was also a decrease in the randomness of the liquid-solid interface (ΔGo values were negative). In overall, the three adsorbents can be used for treatment of water that is contaminated with Ni(II).
- Synthesis and characterization of modified resins and their selective
sorption towards rhenium from binary (Re & Mo) solutions
Abstract: Three amine-functionalized resins were prepared by suspension polymerization of vinyl-benzyl chloride, divinylbenzene, and subsequent amination process. The effect of chain length and cyclic amine on the performance of resins was investigated in a multicomponent system (Re & Mo). N-pentylamine, propylamine, and pyrrolidine were used in the investigation. Different analyses such as scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-optical emission spectrometry (ICP-OES), Kiejdahl’s and Volhard’s methods were used to characterize the synthesized resins. The synthesized resins then were assayed in a batch mode using binary solutions of Re(VII) and Mo to evaluate their efficiency to the selective sorption of rhenium ions. Among all investigated resins, the resin with cyclic amine groups revealed better separation properties in acidic solution (pH=1) with the highest sorption capacity up to 46.4 mg Re/g and a distribution coefficient of 870 that is more attributed to a steric barrier created against the polymeric molybdenum ions that are larger than objective ions in the studied system.
- Voltammetric simultaneous determination of ascorbic acid and acetaminophen
based on graphite screen printed electrode modified with a La3+-doped ZnO
nanoflowers
Abstract: In this work, an easy method was employed to successfully develop La3+-doped ZnO nanoflowers and guar-gum (GG) modified screen printed electrode (La3+/ZnO/GG/SPE), and La3+/ZnO/GG/SPE was applied for the electrochemically detection of ascorbic acid (AA). The electrochemical methods, such as cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical performances toward ascorbic acid on the La3+/ZnO/GG/SPE. Good linearship was observed for ascorbic acid in the ranges of 1.0–700.0 µM, with the detection limits of 0.03 µM. Moreover, this sensor proved favorable to simultaneously determine ascorbic acid and acetaminophen. Finally, the modified electrode has fairly good performance during the employment of real sample analysis to determine the content of ascorbic acid. These results indicate that the La3+-doped ZnO nanoflowers are supposed to be a promising material in the electrochemical determination of ascorbic acid and acetaminophen in real samples.
- Investigation of Manganese Ions Removal from Waters Using Sewage Sludge
Ash
Abstract: : In this study, the removal of Mn2+ ions from waters by the adsorption method using ash obtained from a treatment plant sludge burning unit, which is treatment plant waste and mostly disposed of in landfill, was investigated. By determining the most suitable conditions for adsorption, adsorption kinetics, isotherms and thermodynamic values were determined. In the experiments, 63.9% removal efficiency was achieved using 10 g L-1 adsorbent concentration for 10 mg L-1 Mn+2 under optimum conditions. As a result of the research, it was determined that the adsorption proceeds according to the pseudo second degree reaction and abides by the Langmuir isotherm. The thermodynamic constants of ΔH°= -4.866 kj mol-1 and ΔS°= 21.44 j mol-1 were determined. As a result of this, the reaction was exothermic, spontaneous and random, and adsorption was physical adsorption. As a result of the study, sewage sludge ash can be used in the treatment of water containing low concentrations of Mn2+.
- Synthesis and biological activity of a new Pt(II) complex involving
4-bromo-2,6-bis-hydroxymethyl-phenol and nicotinamide
Abstract: In the present study, a Pt(II) complex including 4-Bromo-2,6-bis-hydroxymethyl-phenol (BBHMP) and nicotinamide (NA) was synthesized and structurally analysed by using spectral and thermal analysis methods. BBHMP and its Pt(II) complex in the presence of BBHMP and NA were investigated for their antimicrobial, cytotoxicity, gene expression and antioxidant properties. The antimicrobial activity results showed that the platinum complex displayed significant effect against Staphylococcus aureus and Candida albicans. The cytotoxicity of BBHMP and platinum complex were determined against human prostate adenocarcinoma (DU145) and breast (MCF7) cancer cell lines by applying the MTT assay. Cytotoxicity results suggested that the Pt(II) complex exhibited moderate cytotoxicity against growth of these cancer cell lines when compared with the reference drug cisplatin and is more effective than free BBHMP and NA. Gene expression results proved that the Pt(II) complex is a special bioactive chemical constituent and potential anticancer agent. The results obtained showed that the complex was highly inhibitory effects on gene expression. In addition, Pt(II) complex also displayed effective antioxidant activity.
- Evaluation of Microbial and Sensory Properties of Jug Cheese Packed in the
Biodegradable Film of Polyvinyl Alcohol and Pinto Bean Starch-Containing
Garlic, Ginger, and Cinnamon Essential Oils
Abstract: Introduction: Biodegradability and antimicrobial activity of food packaging materials are the most important parameters of modern food packaging industries. Therefore, the present study aimed to use a biodegradable film of polyvinyl alcohol and pinto bean starch-containing cinnamon, garlic, and ginger essential oils to increase the shelf life and reduce the microbial load of the jug cheese and compare with conventional packaging. Methods: For this purpose, jug cheese in the biodegradability film of polyvinyl alcohol/pinto bean starch (20/80%) containing different concentrations (3.125, 6.25, and 12.5%) of cinnamon, garlic, and ginger essential was packaged and their microbial and sensory properties were evaluated during 60 days of storage at 4 ° C and compared with the control sample.Results: The results showed that the use of biodegradable film containing essential oil significantly reduced the microbial load in jug cheese samples. Total count of microorganisms, amount of staphylococcus aureus, coliform, mold, and yeast in samples of jug cheese packed in a biodegradable film containing 6.25 and 12.5% cinnamon essential oil and 12.5% ginger essential oil after 60 days of storage was within the acceptable national standard. The highest general acceptance score among the acceptable samples of national standard belonged to the sample of jug cheese packed in a biodegradable film containing 6.25% of cinnamon essential oil.Conclusion: The use of biodegradable films based on pinto bean starch and polyvinyl alcohol along with cinnamon and ginger essential oils are solutions that can reduce the microbial load and increase the safety of food products during storage and prevent environmental damages.
- Study of Pd complexes adsorption on the γ-AlOOH / γ-Al2O3
layer in activation step for preparation of palladium composite membrane
Abstract: The Pd composite membranes were fabricated by an improved electroless plating procedure. The wetness-impregnation technique was applied for ceramic substrate activation. The adsorption Pd complex on the γ-AlOOH or γ-Al2O3 layer was studied in this work. The obtained results showed that the Pd complexes on the γ-AlOOH layer adsorbed more than the γ-Al2O3 layer. Additionally, the effect of Pd precursor concentration on the substrate loading was investigated. The rate of palladium deposition increases at high Pd concentrations. The resulting membrane was characterized by XRD and SEM-EDX analysis. Furthermore, permeation fluxes of the as-synthesized membrane were evaluated for various gases at different H2 Pressure differences. The membrane permeance was determined to 6.8×10−7 molm−2.s−1.Pa at 798 K and 1 bar under pure hydrogen. The hydrogen permeance and selectivity of hydrogen relative to other gases (CH4, CO2, CO, and N2) were evaluated at 773 K. All gases exhibited dilution and inhibiting (especially CO) effects on hydrogen permeation. The prepared membrane does not seem damaged as the permeability recovered after treating with pure hydrogen.
- Economic priority map for horizontal geothermal heat pump installation
using R600a as a natural refrigerant
Abstract: Growing attention in the geothermal heat pump system (GHP) highlights the necessity of using the technology in an optimized way. Since geographic and meteorological conditions have substantial effects on the efficiency of GHP, a technical and economic feasibility study on a regional scale was performed on residential buildings using R600a as a natural refrigerant. The investigation consists of numerical modeling and enhancement of horizontal geothermal heat pump systems (HGHP) by a meta-heuristic algorithm, spatial cooling/heating design load calculation, and regional data exploration to attain a priority map based on economic factors of 96 geographical points in Iran as a case study. The modeling and optimization approach validation was investigated by comparing the computed results with those published in references. Particle swarm optimization (PSO) was used as an optimization tool due to its simplicity and accuracy. The effects of geographical factors, including heating & cooling load, cooling to heating load ratio, and different soil types on the objective function, total yearly cost (TYC), were investigated to have a better picture in a general exploration study. Finally, Iran's HGHP priority map was accurately presented in this study to help policymakers with decisions concerning technology subsidization.
- Polyelectrolyte multilayers on magnetic silica as a new sorbent for the
separation of trace silver in the leaching solutions of antibacterial
products and determination by flame atomic absorption spectrometry
Abstract: A novel, magnetic silica sorbent with polyelectrolyte multilayers (PEMs) on its surface was prepared, and was used for magnetic solid phase extraction (MSPE) of trace Ag+ via flame atomic absorption spectrometry (FAAS). The experimental parameters for the MSPE procedure, such as the pH, type and concentration of eluent, ultrasonic time and effects of co-existing ions were systematic investigated. The detection limit of the developed method was 0.17 ng mL-1 for Ag+ with an enrichment factor of 35. This method was also successfully applied to the determination of trace Ag+ in the leaching solution of different antibacterial products with satisfactory results.
- Effect of clay modifier on the structure and transport properties in
Polyurethane/Clay Nanocomposites as barrier materials
Abstract: In this study, nanocomposites of thermoplastic Polyurethane (TPU) clay are synthesized and used as a gas barrier property. The NCO terminated TPU prepolymer was prepared by solution polymerization method using a 1:2 ratio of Polyethylene glycol (PEG2000) and Tolylene 2,4-diisocyanate (TPI). Organo modified montmorillonite clay, Cloisite 25A(C25A) were used as ample compatibilization with PEG/TPI matrix. The prepared nanocomposite was characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA). The main functional group peaks of the nanocomposite materials are observed in FT-IR spectroscopy. The nanocomposites exhibited better thermal stabilities than pristine Polyurethane which are investigated by thermogravimetric analysis (TGA). Thermal stability in the sample with 5 wt.% of TPU/C25A-5 material has improved up to 70ºC. The XRD results have confirmed the penetration of clay into TPU matrix, with the disappearance of the characteristic peak (2θ = 4.81º) corresponding to the d-spacing of the organoclay. SEM analysis confirmed the dispersion of nanoclay in TPU matrix.The mechanical properties of nanocomposites such as the tensile strength and Young's modulus of TPU/Cl25A nanocomposites were increased with increasing clay percentage. Gas permeability test was studied using a Membrane separation testing unit. Significant improvements in barrier properties were observed. A remarkable decrease was seen in polyurethane incorporated with 5 Wt.% organo clay when tested with oxygen and nitrogen gas.
- Optimization of an Industrial Aerobic Bioreactor using Combined CFD,
Scale-Down, and Experimental Techniques
Abstract: The dissolution of oxygen into the fermentation medium and the appropriate mass transfer conditions are of crucial importance in designing large-scale aerobic bioreactors. The investigation of mass transfer rates and flow structures in a large-scale process by only using experimental methods is hardly feasible, more likely because of the huge running costs. Also, those investigations by only using simulation approaches would not be accurate. Thus, this study is devoted to the application of a facile hybrid simulation/scale-down/experimental approach to optimize the structure and operation of a 400-L bioreactor used for the diphtheria bacteria culture. Assisted by the computational fluid dynamics (CFD) simulation, the effects of engineering parameters such as the type, agitation rate, and location of the impeller, viscosity as well as the air flow rate and inlet place on the hydrodynamics of large-scale bioreactor were studied. Using the concaved blade disc (CBDT) impeller located in the 30-cm distance with an agitation rate of 550 rpm as well as the air inlet place at the bottom with a flow rate of 20 L/min, a superior improvement in air distribution, bubbles size, and kLa value (0.64 s-1) was observed. To verify the simulation results, 15-L bench-scale bioreactors were developed by using a scale-down (equivalent volumetric power (P/V)) strategy. The CFD simulation results implied that the bench-scale and large-scale bioreactors have comparable hydrodynamic environment. Additionally, the kLa values obtained experimentally were very close to the ones got by the simulation. These results make the CFD-assisted optimized 400-L bioreactor a potential candidate for this bioprocess.
- AHP-Based Amine Selection in Sour Gas Treating Process: Simulation and
Optimization
Abstract: The acid gases (H2S and CO2) are unpleasant groups in the natural gas (sour gas) stream, which must be reduced. The presence of acid gases will have operational problems such as corrosion in the processing facilities and, environmental issues like air pollution and greenhouse effects. Therefore, the reduction of acid gases from sour gas is essential via a reliable process. The most common method for natural gas sweetening is the utilization of the amine solution. In the current work, the analytic hierarchy process (AHP) is employed to consider the advantages and disadvantages of each amine solution. The four process criteria and seven alternatives were intended based on the AHP procedure. Then, the natural gas sweetening process was simulated, and finally, operation conditions were optimized. MDEA as an alternative and cost as process criteria were introduced with 21% and 53% as the highest priority, respectively. The reduction of acid gas contents and reboiler duty were chosen as objective functions. The optimization results indicated that the best feed gas temperature and MDEA concentration is 30 ºC and 39 wt.%, respectively. The amount of H2S and CO2 as one of the optimization objectives of gas sweetening achieved 2.4 and 88 ppm in the optimal condition. Accordingly, the MDEA solution consumption was reduced by 5%, and reboiler duty decreased approximately 0.04% compared to the conventional process.
- Exergy and stabilization design of a fusion power plant and its waste heat
recovery to produce hydrogen
Abstract: As climate change becomes a more severe problem each day, the need to respond to it firmly grows in importance. For decades many scientists believed fusion, or, as it is called in the engineering society, the artificial sun, was the future of unlimited clean and cheap energy sources. Since 2007 when the international nuclear fusion research and engineering megaproject started as a mega cooperation project between several industrial countries, this ambition seemed to be at hand more than at any other time. This mega project was a turning point for the fusion sub-projects to emerge in many countries and regions. But as fusion projects grow in number, similar to all other energy systems, a need to analyze the using second law of thermodynamics comes to a great matter of importance. This paper aims to study the European demonstration fusion power reactor pulse integrated power plant and its waste heat recovery potential to produce hydrogen, considering the primary heat transfer systems, the intermediate Heat Transfer System, including the Energy Storage System’s first option to ensure power continuity. This study shows that the fusion power plant is among the most efficient stand-alone energy systems with an overall efficiency of (85.07 and 89.1% in energy storage and auxiliary heater arrangements, respectively). Using waste heat assessments to produce hydrogen resulted in even more efficient plants and an increase of the plant’s overall efficiency to more than 94.15 and 92.05% in energy storage and auxiliary heater arrangements, respectively, close to the Carnot efficiency of a similar ideal plant, and means that the irreversibility is in its minimum state.
- The effects of main formulation and process parameters on characteristics
of frankincense essential oil microemulsions
Abstract: The frankincense essential oil was successfully incorporated into nano-sized microemulsions systems through low energy self-emulsification technique. The effects of main formulation parameters, namely, surfactant, co-surfactant, essential oil and water concentrations, as well as the mixing rate and temperature on mean particle size, polydispersity (PDI), turbidity and antioxidant activities of colloidal frankincense essential oil nanoparticles was investigated. The results shown that all studied independent parameters affect the most characteristics of frankincense essential oil microemulsions, significantly. The antibacterial activities of essential oils were also considerably increased as incorporated into nano-sized microemulsions. It was resulted that the most desired frankincense essential oil microemulsions, with desired characteristics (less particle size, size distribution, turbidity and greater antioxidant activity) could be obtained using high concentrations of surfactant (0.7 g), medium concentrations of co-surfactant, essential oil and water (0.2 g, 0.1 g and 9.2 mL, respectively), and medium levels of mixing rate and temperature (500 rpm and 40 °C). Thus, by tuning the formulation or process parameters the most desired nano-sized essential oils can be prepared as natural preserver or health promoting agents for various food and beverage applications.
- Antimony (III) Removal from Electrolyte of Sarcheshmeh Copper Complex
Refinery using CEC370 and Purolite S957 Resins
Abstract: The major goal of electric copper refinement is to manufacture high purity cathode copper and minimize development expenditures. Elements (Bi, As, and Sb) have an adverse impact on the consistency of the ultimate cathode. Antimony is the key element in the moving sludge formation during the electrolysis phase. With increasing the electrolysis time, the antimony content in the electrolyte and the cathode-based antimony toxicity rise. In this research, CEC370 and Purolite S957 resins were used to isolate antimony (III) from the electrolyte. To evaluate the kinetics of the mechanism in static (discrete) conditions, pseudo-first and second-order, interparticle diffusion, and Elovich models were used. The results demonstrate that the pseudo-second-order model, with the greatest correlation coefficient (for CEC370 resin R2=0.991 and for Purolite S957 resin R2=0.997), can better estimate the kinetics of adsorption processes for both CEC370 and Purolite S957 resins. Furthermore, the results of the control phase of the ion exchange mechanism through the intraparticle diffusion models revealed that the phase of antimony (III) ions arrival at the adsorbent film occurred at the highest rank. This may be triggered mostly by the agitation of the solution. The slope of the rate diagram (interparticle diffusion models) of CEC370 resin suggests is smaller adsorption rate compared to Purolite S957 resin. The saturation phase of Purolite S957 resin was achieved upon moving around 16 liters of electrolyte over the resin, and the saturation phase of CEC370 resin was achieved after moving about 10 liters of electrolyte over the resin in the ongoing process of antimony (III) elimination from the electrolyte (comprising 286 ppm antimony).
- PIXE Elemental Analysis of White Soil Clarifier in Traditional Grape Syrup
Production
Abstract: The white soil is used as clarifier, in the traditional preparation process of the grape syrup, to reduce the acidity and deposit the suspended colloidal substances. Besides increasing the nutrients to grape syrup, the substances in white soil may also have side effects on the final product. In grape syrup production, heating the grape juice and soil mixture to the boiling point makes more soil absorption. Determining the chemical composition and the concentration of the used white soil is vital for producing a healthy product. In this study, white soil samples were collected from 10 areas commonly known as white soil excavation sources in Malayer city, Hamadan, Iran. The dry white soil samples were then prepared to be analyzed by the Proton Induced X-ray Emission (PIXE) technique. Ca had the highest and Mg had the lowest value of concentration among the detected elements of Mg, Al, Si, S, K, Ca, Ti, Mn, and Fe in the collected samples. From the statistical analysis, it was revealed that the Ca content of the soil is significantly incomplete correlated with other detected elements. In addition, Ca, Si, and Al had a significant difference (p < 0.001) with other identified elements. The higher amount of Mn and Fe makes the darker color of the syrup while the higher content of Ca increases the transparency of the syrup color. The grape syrup made from the soil containing the highest level of Ca was tasty, more transparent, and light brown in color.
- Synthesis and Application of Polyacrylamide/Cellulose Gel/Fuller’s
Earth Composite for Removal of Methylene Blue from Water
Abstract: In this study, eco-friendly composite material polyacrylamide/cellulose hydrogel reinforced with fuller’s earth (PAAm/CG/FE), has been synthesized and used for the effective adsorption of the methylene blue (MB) dye. The synthesis of PAA/CG/FE composite followed free radical polymerization method. Chemical compositions and morphology of the synthesized composite has been characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Thermal stability has been determined by TGA analysis. Batch adsorption experiments have been carried out by varying different parameters viz. contact time, pH of solution, and temperature in order to determine the maximum dye adsorption capacity of the composite. Introducing cellulose and fuller’s earth into the polyacrylamide eventually enhanced the structural stability, thermal stability, and MB adsorption capacity. Based on the experimental data, adsorption kinetics has been found to be well correlated with the pseudo-second order kinetic model. It has been found that, the equilibrium adsorption isotherm data perfectly followed the Langmuir isotherm model and maximum adsorption capacities were found to be 48.30 and 56.17 mg/g for PAAm and PAAm/CG/FE composite, respectively. Furthermore, prepared composite exhibits good reusability, and it is economic, eco-friendly and nontoxic material.
- Phase Diagrams for Liquid-Liquid Equilibrium of Neopentyl Glycol + Sodium
Formate + Water
Abstract: Phase diagrams for the ternary (neopentyl glycol + sodium formate + water) system were measured. Phase equilibrium data were obtained at different temperatures of 333.15, 343.15 and 353.15 K. The effect of temperature on the liquid–liquid phase equilibrium was studied and the length, slope of the tie-line at different temperatures for the conjugate phase were investigated. It was found that the tie-line length decreases and the two-phase area is slightly reduced by increasing temperature. The three fitting parameters of the Merchuk and Pirdashti equations were obtained with the temperature dependence expressed in the linear form, respectively. Compared with the Pirdashti equation, the binodal curves were described satisfactorily with the Merchuk equation, further, the plait points at various temperatures were estimated by extrapolation. The Othmer-Tobias and Hand models were used for the correlation of the phase equilibrium behavior. The correlation coefficients of the models were obtained for the corresponding temperatures. The results showed that it was well fitted with the Othmer-Tobias model by contrast with the Hand model.
- Rheological Studies on Interactions between CTAB and PEG in Aqueous
Solution Using RSM
Abstract: : In this work, study of rheological behaviour of aqueous solution of cationic surfactant, cetyltrimethylammonium bromide (CTAB) and nonionic polymer, polyethylene glycol (PEG 3000) has been carried out. Response surface methodology of design of experiment technique was adopted to identify the effect of different variables and their interactions on viscosity. A preliminary experimental investigation was carried out to evaluate the rheological behavior of aqueous PEG, aqueous CTAB and also of the binary solution of them. It is found that they all show Newtonian behavior for a shear rate of up to 1000 s-1 for the studied concentrations. For the shear rate above 1000 s-1 aqueous PEG solution shows shear thickening behavior. Combinations of levels of variables i.e. [surfactant], [polymer] and temperature were determined using face centered central composite design (FCD) of response surface methodology. Through regression a quadratic model was generated and found to be very accurate in describing the relation between response and parameters with R2 =0.987, predicted R2 =0.9412and adjusted R2 =0.9776. Effect of interaction between surfactant and polymer on dynamic viscosity is identified with the help of contour and response surface plots. A sudden increase in viscosity is observed at low CTAB concentrations which were the result of weak interactions between CTAB and PEG and the effect of these interactions is found to be more pronounced at high temperature.
- Effect of Membrane Support Thickness on Supported Liquid Membrane
Extraction of Levulinic Acid
Abstract: One of the most appealing compounds in biomass products is levulinic acid (LA). At the same time, separating LA from biomass products is a significant issue in LA production. Supported liquid membrane (SLM) is a revolutionary technique for separating LA from biomass. This study studied the effect of different casting thicknesses of hybrid polyethersulfone graphene membrane from 300 µm to 450 µm on the membrane characteristic and extraction yield of LA via the SLM process. The liquid membrane impregnated into the membrane support was made of 0.3 M trioctylamine and 2-ethyl-1-hexanol. The morphology, surface contact angles, porosity, tensile strength, and performance of the support membrane were evaluated. The membrane cast at 400 µm extracted the most LA (86%) from the 10 g/L LA feed phase. It had an average porosity of 57.77%, surface contact angle at the top layer of 81.21°, surface contact angle at the bottom layer of 98.02°, and tensile strength of 8.41 N. The membrane casting thickness impacts the character of the membrane support and the overall performance of SLM. A suitable membrane structure is required to overcome the instability of the liquid membrane and increase the lifetime operation of SLM.
- Experimental and Kinetic Modeling Studies on Extraction of Essential Oil
from Vietnamese Calamondin (Citrus microcarpa) by Hydro-distillation
Process
Abstract: Current research refers to the modeling of data from the extraction of essential oils from plant materials via the hydrodistillation method, which is applicable from laboratory scale to production scale. Experimental data from the process were obtained by studying the kinetics of the distillation of calamondin peel essential oil. Kinetic models are based on the extraction mechanism of the essential oil, which involves the amount of essential oil released from the plant cell. On the principle of extracting essential oils, the mechanism of washing and diffusing is the basis for constructing the kinetic model and its assumption is developed in order to give an appropriate model. The descriptive kinetics of the hydro-distillation process is based on two assumptions: instantaneous washing followed by non-stationary diffusion and first-order kinetics (diffusion without washing). These two models were compared to select the optimal model for the extraction process. The results showed that the calamondin peel essential oil extraction process was described by a non-stationary model with an extraction rate constant (k) of 0.038 min-1. The extraction of hydro-distillation essential oil from calamondin peels obtained the highest essential oil content (4.2%) under extraction conditions such as water-material ratio of 3:1 mL/g, the heating power of 204 W, and extraction time 60 min. Furthermore, the chemical composition of volatiles present in calamondin peels oil was evaluated for the sample by using GC-MS. Limonene (88.637%), Germacrene D (4.451%), β-Edudesmol (1.034%) were the major constituents in the essential oils.
- Synthesis of green Ferric nanoparticles from celery leaves for the dye
decolorization by Fenton oxidation
Abstract: The creation of defiant chemical contaminants in the water is a major worry in water treatment processes. Such contaminants can never be readily eliminated with traditional treatment methods. As a result, combining adsorption with advanced oxidation processes is a critical method for removing harmful pollutants. This study aimed to investigate the efficacy of an environmentally friendly, low-cost catalyst that could be used as a heterogeneous Fenton oxidation catalyst. Ferric nanoparticles were synthesised from celery leaf extract (C-FeNPs). The Field Emission Scanning Electron Microscope (FESEM/EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction spectroscopy (XRD) were used to describe the prepared catalyst. Adsorption isotherms of the chosen dye removal method were calculated and the tests were fitted with the Langmuir and Freundlich. The UV-vis spectrometer was used to determine the residual concentration of Orange Gelb (OG) dye in water. Under ideal parameters such as pH, temperature, concentration of OG and C-FeNPs dosage, the highest OG dye decolorization effectiveness of 99% was achieved. According to morphological analysis, nanoparticles with a diameter of 44–55 nm were shown to be responsible for the high catalytic activity. Adsorption data (R2 = 0.9436) is more consistent with the Langmuir model. Furthermore, the adsorption process was accompanied by an oxidation process more efficient.
- Optimize the extraction conditions of pectin extracted from Saveh
pomegranate peels
Abstract: ABSTRACT: In recent years, numerous studies have been done on the beneficial use of food waste. Pomegranate is widely used in food industries, and the skin of this fruit containing the valuable substance, pectin, is discarded as waste. The general aim of this study was to investigate the effect of temperature (35, 65 and 95 ºC), time (40, 120 and 200 min) and pH (1, 2, 3) on the galacturonic acid percentage, degree of esterification (DE) and yield rate of pectin extracted from pomegranate peels and optimize extraction conditions. Therefore, 15 treatments were designed using the response surface methodology (RSM) Box-Behnken and the obtained results were analyzed and optimized by using the response surface method at a confidence level of 95% in Minitab 16 software. The results of analysis of variance (ANOVA) showed that linear effect of temperature, time and pH had significantly (p ≤0.05) affected on the amount of pectin extracted from pomegranate peels. Results showed that hard extraction conditions (lower pH, higher temperature and greater time) have increased the extraction yield and the amount of galacturonic acid of pectin, while these conditions have reduced degree of esterification of pectin. According to the results, the yield of pectin extracted from pomegranate peels, the percentage of galacturonic acid, and degree of esterification varied from 6.96% to 8.65%, 60.31% to 84.64%, and 52.30% to 65.21%, respectively. The multiple optimum extraction conditions to achieve maximum yield of pectin extraction (8.65%) and galacturonic acid (83.49%) with 97.60% desirability were obtained at 94.39 °C, time= 200 min, and pH = 1.24. The results of this study proved that pectin can be extracted from Saveh pomegranate peel with desirable quality properties and used it in food formulations.
- Finite-time Sliding Mode Control for Continuous Stirred Tank Reactor Based
on Disturbance Observer
Abstract: This paper aims to investigate the robust control problem of continuous stirred tank reactors (CSTR). A CSTR is one of the most essential equipment in chemical processes, whose effects of highly nonlinear dynamic and external disturbances make it very difficult to be controlled. Firstly, a novel finite-time sliding mode control is introduced that eliminates disturbance effects and ensures finite-time tracking. Secondly, to better compensate disturbances and to improve controller performance, a finite-time disturbance observer is developed. Finally, an adaptive robust control method is introduced based on the proposed sliding mode control and the disturbance observer. Stability analysis is performed to investigate the finite-time tracking of the closed-loop system under the proposed controllers. Besides, to enhance the performance of the proposed controllers, the design parameters are tuned by the genetic optimization algorithm. Simulation results are produced to confirm the efficiency of the proposed methods in terms of tracking errors and convergence rates. The proposed finite-time sliding mode control and the adaptive finite-time sliding mode control with the settling times of 1.73s and 1.71s as well as IAE of 0.509 and 0.4843, respectively, showed more desirable performance than other controllers.
- Separation of hydrogen sulfide from butane gas mixture by zeolite 13X
Abstract: The Zeolitic adsorbent is successfully synthesized by natural Iranian kaolin to the separation of hydrogen sulfide from a gas mixture. In this work, zeolite 13X from modified natural Iranian kaolin at 65 ˚C for 72 h at various concentrations of caustic soda solution was synthesized using metakaolinization process at 900˚C for 2h. By Taguchi’s experimental design, the best duration and temperature of crystallization were 72 h and 65˚C. Prepared zeolite 13X was characterized using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and N2 adsorption-desorption methods. In addition, the adsorption capacity of zeolite 13X for 310 ppm of hydrogen sulfide mixed with hydrocarbon gas-like butane was investigated using a volumetric method by two different detectors and different temperatures. After the adsorption process, the amount of H2S in output gas was about 108 ppm and this confirms approximately more than 65% adsorption at 25bar and 298K. The results are is in good agreement with experimental results.
- Methylene blue adsorption from aqueous solution using Zn2(BDC)2(DABCO)
metal organic framework and its polyurethane nanocomposite
Abstract: In this work, Zn2(BDC)2(DABCO) metal organic framework (MOF) was prepared by Zn = zinc acetate dehydrates, BDC = 1,4-benzenedicarboxylate, and DABCO = 1,4-diazabicyclo [2.2.2] octane. The MOF and its polyurethane (PU) nanocomposite were used to remove methylene blue (MB) as a harmful and toxic dye from aqueous solution. Polyurethane polymer has been modified with zinc-based metal organic framework by the press method to develop an efficient adsorbent for the first time. Samples were characterized by Fourier transform infrared spectroscopy (FTIR) to evaluate functional groups, X-ray diffraction (XRD) analysis of crystal structure, field emission scanning electron microscope (FESEM) to determine morphology and size, BET analysis for measurement of surface area, and Ultraviolet–visible (UV–Vis) spectroscopy to study MB adsorption. Methylene blue adsorption was reported by changing the amount of adsorbent, MB concentration, pH and temperature of the solution over time. According to the results, increasing the amount and percentage of adsorbent, pH and temperature of the solution increased the percentage of adsorption efficiency. Also, the MOF and its nanocomposite can be a good choice for adsorption of methylene blue as cationic dye due to its high level and low material consumption. The results show that Zn2(BDC)2(DABCO) MOF and its PU nanocomposite can have good potential for the development of various adsorbents.
- Designed a Spectrophotometric Method for the Determination of Tartrazine
Residual in Different Drink and Foodstuffs by Using Mandarin leaves-capped
gold Nanoparticles.
Abstract: Tartrazine color is a synthetic organic food dye that can be found in common food products such as bakery products, dairy products, candies, and beverages, the presence and content of tartrazine color must be controlled in food products due to their potential harmfulness to human beings. Although the liquid chromatographic, other methods for tartrazine color has advantages such as excellent accuracy and reproducibility, it has limitations such as long-time measure, high equipment cost. In this study, for determination tartrazine color in solution we used a prepared from Mandarin Leaves-capped AuNPs sensor and kinetic spectrophotometric method. The calibration curve was linear in the range of (0.02 to 12.0 µg/L). The standard deviation of (3.0%), and detection limit of the method (0.02 µg/L in time 7 min, 385 nm) were obtained for sensor level response Mandarin Leaves-capped AuNPs with (95%) confidence evaluated. The observed outcomes confirmed the very low detection limit for measuring the tartrazine color in food samples. The artificial neural network model was used as a tool very low for determining mean square error (MSE = 0.515) for tartrazine color by Mandarin Leaves-capped AuNPs sensor. The chemical Mandarin Leaves-capped AuNPs sensor made it possible as an excellent sensor with reproducibility.
- Effect of flow field (Stirring) on the heat-induced fibrillogenesis of
β-Lactoglobulin in the presence of Glucose at neutral pH
Abstract: Effect of stirring on the amyloid fibrillogenesis of β-Lactoglobulin (βLG) at pH 7 was studied in the presence of glucose (Glu). Fibrillogenesis was carried out by heating the 0.30 mM βLG solution at pH 7 with and without glucose (37.5 mM) for 24 hrs at ≥80◦C under stirring (250 and 474 rpm) conditions. For control samples, βLG solutions with and without glucose were incubated under unstirred condition. The flow-induced birefringence method was used to characterize the fibrillogenesis, revealed the coil-stretch transition pointing out the existence of worm-like flexible fibrils in all samples. Atomic force microscopy (AFM) was used as a morphology that clearly showed the flexible fibrils in all samples and also revealed that the fibril lengths shortened on increasing stirring rate. This shortening in lengths might be possible due to weak hydrophobic interaction at pH 7 resulting fragmentation of fibrils over stirring. Glucose inhibited the fibrillogenesis of βLG even on stirring.
- Degradation and mineralization of metformin by electro-oxidation on Ti/DSA
(Ta2O5-Ir2O5) anode and combined electro-oxidation and electro-coagulation
on stainless steel (SS) anode
Abstract: We conducted electro-oxidation, and combined electro-oxidation and electro-coagulation batch experiments on synthetic wastewater containing an anti-diabetic drug metformin hydrochloride (MET-HCl). Degradation and mineralization were studies on Ti/DSA (Ta2O5-Ir2O5) and stainless steel (SS) anodes. Electrochemical behaviour was observed by cyclic voltammetry techniques. Effect of applied current density was evaluated at 50 ppm concentration of supporting electrolyte sodium sulphate (Na2SO4). Electro-oxidation on Ti/DSA anode resulted in maximum degradation of 94.88% at corresponding specific charge (Q) of 2.1 Ah/litre, current density of 0.93 mA/cm2 and Na2SO4 concentration of 100 ppm. Similarly, maximum mineralization obtained was 70.64% at corresponding specific charge (Q) of 2.1 Ah/litre, current density of 0.93 mA/cm2 and Na2SO4 concentration of 50 ppm. Energy consumption was 2081.56 kWh/kgTOC. Further, under identical conditions, combined electro-oxidation and electro-coagulation on SS anode resulted in maximum degradation of 99.48% at corresponding specific charge (Q) of 2.1 Ah/litre, current density of 0.93 mA/cm2 and Na2SO4 concentration of 100 ppm. Similarly, maximum mineralization obtained was 99.04% at corresponding specific charge (Q) of 2.1 Ah/litre, current density of 0.93 mA/cm2 and Na2SO4 concentration75 ppm. Energy consumption was 870.98 kWh/kgTOC.
- Assessment of Sodium Silicofluoride as a Fluoride Source in Drinking Water
System
Abstract: In this work, solubility of sodium silicofluoride (SSF) as fluoride source dosed was analyzed and the fluoride dosage was evaluated from a dedicated water treatment plant (WTP) to ensure its single distribution system contains sufficient fluoride level as recommended by the national drinking water standard. The solubility of SSF from different suppliers namely SSF1, SSF2, and SSF3 were studied at different range concentration using the gang jar test. Fluoride levels in the drinking water system were evaluated by taking the water sample from 7 sampling points, where fluoride dosages were grouped at three different ranges of fluoride concentration at the dosing tank; (i) low (4.6 g/L), (ii) medium (7.1 g/L), (iii) high (11.8 g/L). Results show that at a high range of fluoride dosage, 10.4% of insoluble substance was recovered from dilution of SSF3, much lower amount than SSF1 and SSF2 indicating SS3 as the best quality fluoridating agent for the system. Spectroscopic analysis shows that a high concentration of fluoride is required to obtain the concentration at allowable limit. Dosing tank having medium range of fluoride concentration shows a mean of fluoride level of 0.60 mg/L at the sampling points along the distribution system. Therefore, the dosage of SSF for fluoridation at WTP is recommended at medium range fluoride concentration in order to obtain desired concentration at the distribution system.
- THE RECOVERY OF MICROPLASTICS FROM ROCK OYSTERS USING DIGESTION METHOD
Abstract: The widespread deposition of microplastics (<5.0 mm) in the marine environment have appeared to be pervasive across the globe. It has led to major attention of many researchers to study this problem. Despite the amount of work conducted to understand these infamous microplastics, there is still no standard procedure for microplastics extraction from marine organism samples. This study investigated three types of digestion treatments; (1) KOH, (2) KOH/H2O2, and (3) KOH/NaClO, followed by density separation using 50% KI to extract the spiked microplastics from the rock oyster. Each treatment was tested to study the digestion effectiveness of the organic soft tissue materials while preserving the microplastic particles. Aside from recovering the spiked microplastics, other small contaminants have been detected in each treatment. All the spiked microplastics and the contaminants obtained were analysed using microscope and FTIR for characterisation. From this study, it was observed that each treatment resulted in high microplastics recovery. Among the three treatments, using 10% KOH alone provided the highest digestion rate, but it required more time to digest the oyster soft tissue. The contaminants detected in the oyster suggested the possibility of microplastics accumulation in non-digestion organs through adherence.
- Evaluation of the Combustion and Emission Parameters of Waste Transformer
Oil and Its Diesel Blends
Abstract: The production of fuel from waste transformer oil (WTO) is an excellent way to produce alternative fuels. The aim of research in this paper is obtaining fuel by mixing WTO with diesel fuel in different mass ratios that can be used as an alternative fuel for low power heat generators as well as for internal combustion engines. Waste oils are serious problem for environment due to their disposal, and are considered as useful energy sources for their high calorific value. Taking these facts into account, researches were conducted to evaluate the combustion and emission parameters in a boiler furnace of 40 kW using waste transformer oil (WTO) and its four diesel blends by varying WTO mass fractions from 20% to 50%. The results were analysed and compared with diesel fuel. An increase of NO, CO, CO2 emissions was observed for WTO and its diesel blends and compared to diesel. The flue gas temperature in the kiln is high for the WTO, which indicates the efficiency of the input energy. During the flue gas purification in a gas washing bottle, concentrates of sulfate, sulfide, nitrate and nitrite were recorded.
- SYNTHESIS AND STUDY OF MODIFIED ALKYLPHENOLATE ADDITIVES FOR MOTOR OILS
Abstract: The article presents the results of research on the synthesis of new medium alkaline AKI-31, AKI-57 and high alkaline additives AKI-124 and AKI-134.Additives AKI-31 and AKI-57 are calcium salts of condensation products of dodecylphenol, formaldehyde and aminoacetic (AKI-31) or p-aminobenzoic (AKI-57) acid.Highlyalkaline additives AKI-124 and AKİ-134 are carbonated calcium salts of condensation products of dodecylphenol, formaldehyde and aminoacetic acid (AKI-124) or p-aminobenzoic acid (AKI-134).The high performance properties of the additives have been confirmed by standard research methods. Studies have shown that the additives have high antioxidant, anticorrosive and detergent properties.Highly alkaline additives AKI-124 and AKI-134 were studied by thermal analysis methods. It is shown that the additives are highly resistant to temperature effects.By using highlyalkaline additives, M-10G2 motor oils have been developed, which in terms of basic performance indicators correspond to GOST 8581-92 and are on a par with the foreign analogue of Shell.
- Synthesis of green zinc oxide nanoparticles mediated by Syzygium cumini
induced developmental deformation in embryo toxicity of (Daniorerio)
zebrafish
Abstract: This study investigated the synthesis of Zinc oxide (ZnO) nanoparticles using Syzygium cumini fruit (Indian blackberry) seed extract. The seeds extract of Syzygium cumini fruit have properties of anti-diabetic, anti-inflammatory, anti-bacterial, and traditionally it has long been used in Indian folklore medicine. Zebrafish embryos and larvae were treated with 5 different concentrations (0, 25, 50, 75, 100, 150 µg/ml) of Zinc oxide (ZnO) nanoparticles from 4 hours post fertilization (hpf). The results showed that exposure of 50-150 µg/ml zinc oxide nanoparticles (ZnO NPs) induced developmental toxicity in these embryos, causing mortality, hatching delay, and malformation. Exposure of 50-150 µg/mL Zinc oxide (ZnO) nanoparticles to zebrafish embryo caused coagulated unhatched phenotype, spinal curvature, axis bent, tail malformation, yolk sac and pericardial edema, at 72-96 hpf. These results will assist in elucidating the mechanisms of the developmental toxicity of green synthesized Zinc oxide nanoparticles during embryonic development of zebrafish.
- Biosorption of Cr(VI) ions onto walnut flowers: application of isotherm
models
Abstract: Biosorption of Cr(VI) ions onto walnut flowers (WF) is studied in a batch system in relation with the physical parameters. The efficiency approaches 100% with 5 g WF L-1 at pH~1.5 for a Cr(VI) concentration of 100 mg L-1 in less than 1 h. The experimental data are analyzed using two-parameter models (Langmuir, Freundlich and Temkin), and three-parameter models (Redlich–Peterson, Sips and Toth). In order to determine the best isotherm, two error analysis methods are used to evaluate the correlation coefficient and chi-square test. The error analysis demonstrates that the three-parameter models better describes the Cr(VI) biosorption data. The Sips equation provides the best fitting. The possible interaction between the Cr(VI) and biosorbent surface was evaluated by FTIR analyses. Overall, the proposed biosorbent material was successfully used for the removal of a Cr(VI) from contaminated solutions.
- An increase in the copper recovery of the Sarcheshmeh copper complex
through reagent modifications
Abstract: In the flotation of sulfide minerals, particularly in the separation between pyrite and chalcopyrite, adjustment of the pH and reagents dosages is very important. Process auditing at the Sarcheshmeh copper complex showed that the pH in the rougher cells was greater than 12, while according to the initial design, the pH in the rougher cells should be 11.5. Also, it was found that the collectors and frothers dosages were 21.6 and 25.1 g/t, respectively, which is much lower than the initial design. Also, plant audit showed that, this operation method was used because of an idea about higher froth stability and easier operation in the higher pH values. In addition, it was observed that by suddenly changing the reagents and pH regime to the initial design, operation stability and therefore the copper recovery were also reduced quickly. Hence, in this study pH was decreased and reagents dosages were increased step by step. The results showed that after adjustment of the pH in the range of 11.5-11.7 and increasing the collectors and frothers dosages to 29 and 31 g/t, respectively, the copper recovery was increased about 2%, and the operation stability was not reduced.
- Isolation, structure elucidation, and standardization of Suberosin and
glycyrrhizin from and Ferulago trifida L. and Glycyrrhiza glabra L.
Abstract: Introduction: Natural products are often used as starting points for drug discovery, followed by synthetic modifications to reduce side effects and increase bioavailability. Approximately, fifty percent of the approved drugs at the U.S. Food and Drug Administration (FDA) are inspired by natural products. Glycyrrhizin is a well-known anti-inflammatory component that has been shown to prolong the coagulation time of thrombin and fibrinogen and to increase the duration of plasma recalcification in vitro. It is considered to be the first plant-based thrombin inhibitor. Suberosin, also known as 7-methoxy-6-prenylcoumarin, belongs to the class of coumarin compounds.Objective: The purpose of this article is to purify, identify, and standardize of glycyrrhizin and suberosin, from Glycyrrhiza glabra L. and Ferulago trifida L.Method: First, two plants were pulverized and then extracted using a percolator. The extracts were then divided into different fractions by column chromatography and mixed with a thin layer chromatography. Finally, we obtained pure compounds after using column chromatography and thin-layer chromatography. 1H-NMR, 13C-NMR have used to purified compounds and also the HPLC method was used to standardize these compounds.Result: Glycyrrhizin and Suberosin were extracted from Glycyrrhiza glabra L. and Ferulago trifida L respectively and 1H-NMR 13C-NMR techniques approved the structure of these two compounds, also, standardization of these compounds were correctly done by HPLC.
- Synthesis of aureobasidin B analogs and their antifungal activity against
Candida albicans
Abstract: Aureobasidins (Abs) are a class of cyclodepsipeptides with interesting antifungal properties but they are difficult to synthesize. This study aimed to synthesize analogs of aureobasidin B (AbB) by a combination of solid- and solution-phase synthesis and to investigate their antifungal properties. The linear peptides were synthesized on 2-chlorotrityl chloride resin with Fmoc strategy and a range of coupling reagents including HATU/HOAt, HBTU/HOBt, and BTC/sym-collidine. Cyclisation step was undertaken in solution phase. Four cyclic nonapeptides (NP1-NP4) and ten cyclic heptapeptides (HP1-HP2, HP4-HP11) were successfully synthesized and characterized. The analogs NP1, NP4, HP1, and HP2 demonstrated moderate antifungal activity against Candida albicans.
- In-situ synthesis of KO2 nanocrystals on porous fiberglass matrix as an
air regenerative product
Abstract: The in-situ synthesis of KO2 nanocrystals on porous fiberglass matrix is a promising route for the development of air regenerative products as chemical lungs. The preparation process was studied experimentally with Taguchi experimental design L18 orthogonal array (35) to examine the effect of five physicochemical variables at three levels. Maximum active oxygen content (Oact wt.%) as the objective of optimization was determined by hot air at a temperature of 120 °C, flow rate 325 L.min-1, time of 10 min with 10 cm distance from the matrix, and alkaline solution 1.5%. The analysis of variance (ANOVA) with Fisher’s test revealed that the hot air temperature has the most significant effect on the response. The XRD pattern and TGA decomposition curves of the optimal sample confirmed the form of KO2 nanocrystals as a major phase on the matrix. The morphology and elemental analysis of the product determined by FESEM and EDX analysis have been evenly distributed both in pores and on the surface of the matrix in the form of spherical or quasispherical grains (10-40 nm in diameter). The BET specific surface area of KO2 nanocomposite was measured about at 1.252 m2g-1 and they have a mesoporous solid structure. The best CO2 adsorption kinetic model was the Elovich model which fits the experimental kinetic data. The thermodynamic parameters represent the spontaneous and exothermic processes.
- New Proton-Exchange Membrane (PEM) based on the Modification of Sulfonated
Polystyrene with MIL-53(Al)-NH2 for Direct-Methanol Fuel Cell
Abstract: In this study, modified sulfonated polystyrene (SPS) was used as base for membrane fabrication in direct methanol fuel cells (DMFCs). The sulfonated polystyrene (SPS) was prepared using ethylsulfate and polystyrene with sulphate attached to para-position of some phenyl groups in polystyrene backbone and conducted by polyethylene (PE) and different amounts of MIL-53(Al)-NH2 as metal-organic material, to obtain SPS-PE-MIL-53 as a novel proton-exchange membranes. The membranes were characterized using FT-IR spectroscopy, SEM, and TGA analysis. The proton conductivity, water uptake, oxidative resistance, ionic conductivity, and the methanol permeability of the membranes were examined to assess its performance in a direct methanol fuel cell. The modified membrane containing 1% wt SPS, 1% wt PE and 0.25% wt MIL-53 showed relatively better performance than the other prepared membranes with the selectivity factor of 7.17 × 104 S.s/cm3 and a maximum peak power density of 17.04 mW/cm2 with a maximum current density of 115.38 mA/cm2.
- Pore Space Characterization of Carbonated Binary Micro-Computed Tomography
Images, Case Study
Abstract: Pore space characterization helps better understanding of porous media. The pore geometry and topological properties in carbonated rocks are important for a better understanding of the complex hydrologic and elastic properties. Detailed model of the pore space constructed directly from three-dimensional images can bring reliable results because the porous media complexity would be considered. In this study, by considering different methods a deep understanding from some carbonated pore spaces are obtained. Four series of 2D micro-computed tomography binary images for carbonated rock have been collected; and each of them was considered as a 3D binary image. Using novel skeletonization and pore-throat segmentation algorithms, some network properties have been evaluated and compared for the four cases. Those considered properties were pore and grain size distribution, throat length frequency and coordination number frequency.Moreover, the geometric measures in 2D and 3D have been considered using Minkowski functionals. The area, the perimeter, and the 2D Euler number of 2D binary images and the volume, the surface area, the mean breadth which is also known as the integral of the mean curvature, and the 3D Euler Number of the 3D binary images are also considered.
- Mathematical modeling and simulation of fluidized bed gasifier:
Application to Indian coal
Abstract: An Eulerian–Eulerian based two-dimensional mathematical modeling approach for bubbling fluidized bed gasifier using FLUENT has been proposed to transfer energy, momentum, and mass between two phases namely solid and gas together with the application of the kinetic theory of solid particle flow. The modeling equation involves eight homogeneous and five heterogeneous reactions kinetics. The eddy dissipation model of FLUENT has been used to incorporate homogeneous reactions kinetics and a user-defined code has been developed that describes the kinetics of heterogeneous reactions. The simulation result shows that the exit syngas composition is in line with the experimental one and having a maximum error of around 4.05% for CO and 2.68% for hydrogen. The temperature data obtained from the modeling of the gasifier validated the experimental data within ± 1.79% of error. The syngas composition obtained from the model of bubbling fluidized bed gasifier is in good agreement within a maximum error of less than pm5% with the experimental data obtained from the pilot plant. Moreover, the maximum value 55.69 mol%. of hydrogen concentration is obtained for steam/coal ratio of 1.3.
- Using Bentonite Clay as Coagulant Aid for Removing Low to Medium Turbidity
Levels
Abstract: Alum is a widely used coagulant around the world, but the use of it is associated with some problems, as it increases the aluminum residuals, which have been linked to Alzheimer's disease. Coagulant aids may help with reducing the needed dose of alum.In this paper, many sets of experiments were done to determine the effect of using bentonite clay as a coagulation aid. The experiments were performed under different conditions and on different seasonal circumstances, where many alum and bentonite clay doses were used at low to medium initial turbidity levels. It was found that the addition of a small dose of bentonite clay; 5 mg/L improves the coagulation efficiency between 5 to 7.5 % for Alum dose 10 mg/L and between 10.6 to 14% for the alum dose 15 mg/L. The coagulation process was also studied by changing both the temperature and the pH value; the best performance of bentonite was when pH is 5 and 6, and when the temperature changed between 10 to 25, the improvement of the removal percentage was about 30 % for the low turbidity and about 9% or the high ones. Finally, the effect of changing the settling time and the mixing speed was also studied. In this regard, it was observed that the best settling time was 90min and the best stirring speed was 200 rpm
- Comparative catalytic behavior of prepared cobalt or iron salt of
manganese substituted polyoxometalate supported on silica in oxidation of
benzyl alcohol
Abstract: Cobalt and iron salt of mono manganese substituted keggin polyoxometalate have been prepared and supported on silica as heterogeneous catalysts. The prepared compounds were completely characterized by conventional techniques such as FTIR, ICP-OES, XRD, FESEM, and BET. The results indicated that the primary Keggin structure remain intact in the obtained samples and the prepared particles were in the nanoscale. and The surface area of silica support decreased after loading of the cobalt and the iron salt of manganese substituted Keggin polyoxometalate on it. Application of the prepared compounds for demonstration the effect of transition metals such as cobalt (or iron) combined with mono manganese substituted polyoxometalate was investigated in solvent free oxidation of benzyl alcohol, as a model reaction, using H2O2. The results proved that selectivity of the silica supported cobalt salt of mono manganese substituted keggin polyoxometalate catalyst to benzaldehyde was more than of the other samples. The catalyst can be reused for several runs without losing significant activity.
- Optimization of tomato slices drying in a continuous infrared-assisted
Refractance Window TM dryer using response surface methodology
Abstract: The present work was aimed to investigate energy consumption and quality of tomato slices dried in an infrared-assisted refractance windowTM (IRARW) dryer. The response surface methodology was used to optimize the experimental factors, including water temperature, infrared (IR) power, and belt speed based on specific energy consumption, IR fraction, contents of ascorbic acid, total phenolic, and total lycopene and color indices (L*, a*, b*, and H°). All factors, except the belt speed in the range of 0.278 - 0.37 mm/s, had significant effects on the performance parameters. The maximum measured value of specific energy consumption, IR fraction, contents of ascorbic acid, total phenolic, and total lycopene were 1.76 kWh/kg, 60.4%, 302.2 mg/100g, 708.07 mg GAE/100g, and 38.61 mg/100g, respectively. Rising the IR power led to an increase in a* and a decrease in L* values of the color indices. The optimum drying condition was determined to be at the temperature of 70 °C and the IR power of 500 W.
- Synthesis and Application of Hydrogels for Oil-Water Separation
Abstract: A cotton-based hydrogel nanocomposite was effectively arranged through free radical graft co-polymerization of a combination of acrylic acid (AA), acrylonitrile (AN), and sodium acrylate (NaA) onto the texture pursued by the addition of Ag nanoparticles. Ammonium persulfate (APS) and potassium persulfate (KPS) were utilized as initiators within sight of a crosslinker methylene bisacrylamide (MBA). These samples are characterized by Fourier transform infrared (FTIR), x-ray diffraction (XRD) to affirm the hydrogel nanocomposite structure. At first, the influencing factors onto graft polymerization were efficiently enhanced to accomplish a hydrogel with a swelling limit as high as expected under the circumstances. The came about nanocomposite shows overly hydrophilic and super hydrophobic properties. In this manner, the grafted texture, specifically from oil/water, blends separated water with high separation productivity. The impacts of channel type, level of covered hydrogel on cotton, nearness of Ag nanoparticles, extricated oil type, and temperature effect were studied on the hydrogel. Nanocomposite on the partition effectiveness of channels was additionally examined. The as-prepared materials were super hydrophilic and superoleophobic in air and submerged in water. Diesel oil and vegetable oil were used selectively at 10% and 20% volume in water. The separation efficiencies for each were observed on different samples, with and without Ag nanoparticles. The materials can isolate the scope of various oil/water blends with >97% separation efficiency. Effect of poly AN-CO-NaA and poly AN-co-AA ratios the samples show the same nature, their weight increases with time. The rates were different owing to the monomer ratios. Hence the more the hydrophilic groups present, the greater the absorption rate, which shows the characteristics of this poly AN-co-AA grafted hydrogel. Sodium acrylate at different proportions in poly AN-co-NaA was tested, it can be deduced that hydrophilicity increased with greater proportions of the sodium acrylate.
- PROPANE OXIDATIVE DEHYDROGENATION ON BiP1-XVXO4 SUPPORTED SILICA CATALYSTS
Abstract: The molecularly dispersed BiP1-xVxO4/SiO2 supported oxides, with x varying from 0 to 1, were prepared by impregnation of Bismuth, Phosphorus and Vanadium on silica. Their structures have been characterized by different techniques: X-ray diffraction, Raman spectroscopy, Temperature-programmed reduction of catalysts in H2 (H2-TPR) and methanol oxidation reaction. This very sensitive technique provided us with relevant information on the nature of the active sites (acid-base and redox) on the surface of the catalysts. The results of the characterization show the structural evolution of the vanadium species of the isolated crystallites from V2O5 for x =0.3 and x =0.5, to BiVO4, with disappearance of BiPO4, with the increase of the vanadium content from x=0.5 to x = 1. The oxidation of methanol showed the basic properties of the BiPO4/SiO2 catalyst, by the formation of carbon dioxide as the major product of the reaction. The substitution of phosphorus with vanadium promotes the formation of formaldehyde, confirming the presence of redox sites on these substituted catalysts. These catalysts were examined in the oxidative dehydrogenation (ODH) of propane. For x ≥ 0.5, the dispersed BiVO4 exhibited significant activity in propane ODH than the BiPO4 and V2O5 crystallites, with good selectivity to propylene and acrolein, consistent with their high reducibility confirmed by H2-TPR, and the presence of redox sites shown by the oxidation of methanol. The catalyst with x = 0 was less selective for propylene due to the favorable combustion of propylene during its formation. Such an understanding of the intrinsic catalytic properties of the BiP1-xVxO4/SiO2 oxides and in particular the BiPO4 and BiVO4 crystallites provides new information on the structural requirements of the propane ODH reaction, beneficial for the design of more efficient Bi-P-V-O based catalysts for propylene and acrolein production.
- Adsorption behavior of rifampicin from aqueous solution onto locally
available mud: Equilibrium, kinetics, and thermodynamic study
Abstract: Several methods have been implemented to eliminate antibiotics from wastewaters. Serious issues are associated with the disposal of antibiotics into the aqua resources, resulting in the contamination of these systems. The utilization of natural adsorbents, like clays and naturally derived adsorbents, have been tried to solve this problem. Red mud was examined as an adsorbent for multiple pollutants in this regard. This work reports the utilization of the Iraqi red mud as a priceless and effective adsorbent for eliminating Rifampicin antibiotic from its aqueous solution after being activated with 10 % HCl to enhance its surface area. BET surface area, Field Emission Scanning Electron Microscope, Fourier Infra-Red spectroscopy, Energy Dispersive X-ray, and X-ray Diffraction of both the raw mud and its activated sample were determined. The BET surface area of the Iraqi red mud raised from 30.99 m2/g to 60.96 m2/g because of the acid treatment. The influence of the adsorption operative factors, including the solution pH, Rifampicin initial concentration, adsorbent dosage, temperature, and contact time, on Rifampicin elimination by the activated red mud, was inspected. The typical adsorption capacity of Rifampicin by the activated red mud was 217.93 mg/g utilizing 0.20 g of the activated red mud at 328 K for 180 minutes contact time in an acidic medium (pH = 4.0). The Langmuir model best described the adsorption behavior of Rifampicin over the activated red mud due to its higher correlation coefficient value (R2 = 0.9928) than that of the Freundlich model (R2 = 0.9117). Rifampicin adsorption by the activated red mud followed the pseudo-second-order kinetic model. Thermodynamic analysis revealed that the adsorption of Rifampicin favored high temperatures, suggesting that the adsorption is endothermic in nature and spontaneous. Finally, the activated red mud is an eco-friendly and reusable adsorbent to remove antibiotic pollutants.
- Sensitivity analysis of coal and bagasse co-firing in an Integrated
Gasification Combined Cycle Power Plant
Abstract: Integrated Gasification Combined Cycle power plants generate electricity by utilizing the syngas obtained from the carbonaceous materials via gasification. These systems commonly use coal fuel; however, biomass fuels like bagasse could be a more environmentally friendly option. This study was aimed at analyzing the effects of varying operating parameters (such as temperature, pressure, O2/fuel, and water/fuel ratios), and fuel feedstocks (i.e., coal, bagasse, and coal-bagasse co-firing) on the syngas composition. Based on the data obtained from a commercial power plant, an equilibrium model was developed and validated using the Aspen Plus® software. Sensitivity analysis was carried out by varying the considered operating parameters and selected fuel feedstocks. The results of this study have manifested that low temperatures, low O2/fuel ratio, and high water/fuel ratio produce syngas with a comparatively higher H2/CO ratio. Highest H2/CO ratios of 1.16, 0.99, and 0.84, were obtained for bagasse, co-firing, and coal, respectively at operating parameters of 1200°C temperature, 0.5 O2/fuel, and 0.6 water/fuel ratios. Furthermore, bagasse and co-firing of coal-bagasse feedstocks could provide a better quality of as compared to that of coal feedstock. The results of this study would also help to operate the Integrated Gasification Combined Cycle plants at optimum performance by utilizing different fuels and by appropriately adjusting the operating parameters.
- Preparation, optimization and characterization of biochar using zero
liquid discharge (ZLD) sludge of a wastepaper based paper mill.
Abstract: This paper reports the preparation of biochar from sludge generated in a wastepaper-based paper mill operating on the ZLD principles. Biochar has been prepared from sludge, hereafter referred to as ZLD sludge, in a laboratory muffle furnace using the slow pyrolysis method. The effect of pyrolysis temperature and pyrolysis time on biochar yield, surface area and pore volume of biochar has been studied by applying response surface methodology. The pyrolysis temperature and pyrolysis time were maintained in the range 450-750oC and 100-200 min. respectively, under the central composite design. It was found that temperature and time significantly impacted the biochar’s yield, surface area, and pore volume of biochar showing strong linear, quadratic, and interaction effects. ANOVA of the empirical models developed in this study was found to be efficient with high R2 predicted, (R2adjusted – R2predicted) < 0.2, adequate precision ˃ 4, and non-significant lack of fit value. The optimum and were determined to be 539.65°C and 176.67 min correspondingly having desirability value 0.651. The optimized values of biochar’s yield, surface area, and pore volume for ZLD sludge biochar were found to be 63.95%, 40.23 m2/g, and 0.048 cm3/g respectively. The physicochemical (proximate and CHNS) and instrumental (XRD, TGA, DSC, FTIR, and SEM) analysis along with their comparison with other biochar reported in literature confirmed the use of this biochar as an adsorbent in wastewater treatment.
- Mineralogical and Physicochemical Characterization of Enugu Iva-Pottery
Silica- Rich Deposit for Ceramics Applications.
Abstract: The exploration of indigenous raw materials that are pure and simple to process for ceramics is a scalable option for locally made ceramics products. This study involves the characterization of unexplored silica-rich sand deposits at Iva-pottery, Enugu North local government area in Enugu state Nigeria for their ceramic industrial potentials. The physicochemical properties of Iva-pottery silica-rich sand were determined. The crystalline phase components and elemental compositions of the oxide were investigated with an x-ray diffractometer and x-ray fluorescence spectrophotometer respectively. The silica was used in ceramics composition as a filler and glaze formulation as glass former. The results obtained showed mainly siliceous crystalline phase with minor amorphous phase and contains 74.55% SiO2, 13.02% Al2O3 and 0.55% Fe. The grain size in the raw form is in the range of 0.18 mm to 0.075 mm (100mesh to + 200 mesh range) without involving ceramic raw materials processing equipment such as ball mill as well as high percentage alumina (13.02) contents as compared to conventional silica with alumina 0.02% to 0.5% range. The high alumina which forms mullite at sintering temperature brings about a low thermal coefficient and hence, suitable chemical stability and resistance to thermal shock. These rare qualities make the Iva-pottery silica-rich sand an emergent material suitable for glaze formulation and filler in ceramic bodies. Thus, it is recommended that the Iva-pottery silica-rich sand deposits in their raw form can be exploited for the formulation of varied glaze temperature ranges and also for the refractory industry. Iva-pottery silica-rich deposits in their raw form, do not meet the requirements of high tech- ceramics applications.
- Gas-liquid flow and coalescence characteristics of bubbles in expansion
microchannel
Abstract: The flow behavior of bubbles in the expansion of the microchannel is studied. Four stable flow patterns are observed: double-layer-bubble coalescence (DLBC), hamburger-double-layer-bubble coalescence (HDLBC), hamburger flow coalescence (HFC), and non-coalescence hamburger flow (NCHF). With the increase of gas velocity, the flow pattern changes gradually from DLBC to HDLBC, HFC and UHFC. The experimental results show that the liquid film drainage time increases with the bubble length. The location of bubble coalescence is away from the inlet with the increase of bubble length and bubble velocity but move towards the inlet with the increase of liquid slug length. A prediction equation of bubble coalescence position is proposed, which has a good prediction effect.
- Average shear rate estimation in conventional stirred-tank bioreactor
using non-Newtonian fluid: An experimental approach
Abstract: An experimental approach for the estimation average shear rate (γav) in stirred tank bioreactor has been proposed for the turbulent flow regime. Based on the proposed methodology, correlation for the estimation of estimation of γav was obtained as a function of agitation speed (N), superficial gas velocity (Vs) and the rheological properties of the non-Newtonian fluids. The γav estimated by the present method was found to be within the range of values calculated by correlations available in the literature. The γav increased with increase of agitation and sparging in all the conditions tested. The correlation derived in the present work helps in estimation of estimation of γav as a function of bioreactor geometry along with physical conditions (N and Vs) and rheological properties (n and K) of non-Newtonian fluid in commercially available stirred tank bioreactor.
- Investigation of diesel engine distinctiveness fuelled by Aegle marmelos
pyrolysis oil-CuO nanoparticles-diesel modified opus with the aid of
Infra-Red thermal images-A novel study
Abstract: Nano particles based catalysts are additives that can be used in green fuels to improve the characteristics of an engine. In the present study, non-edible Aegle marmelos (AM) de-oiled seed cake biomass is used for the production of pyrolysis oil. The copper oxide (CuO) nano particles are prepared via Sol-Gel process and categorized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FTIR). The CuO nano particles are mixed with pyrolysis oil-diesel opus at a fraction of 30 and 50 ppm. Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) tool is employed to attain the optimum engine process parameters. The correlation between cylinder head temperature and exhaust emission was concluded by using an innovative approach of thermography image processing. The outcomes of experimental, TOPSIS and image processing revealed that modified fuel opus emitted a lesser amount of carbon monoxide, oxides of nitrogen, and unburned hydrocarbon compared with diesel but augmented CO2 (Carbon dioxide) emission. It is found that higher CO2 emission is apparent for the dynamic combustion process. This study confirms that AM bio-oil opus is an affordable alternate fuel for diesel engines for a clean and green environment.
- Kinetic and Thermodynamic Study of Methyl Orange dye Adsorption on Zinc
Carbonyldiphthalate, an Organometallic-based Material Prepared with a
Montmorillonite Clay
Abstract: ABSTRACT: Our work is related to the use of adsorption as an effective physical method for the water treatment contaminated with toxic dyes generated by various industries. We focused on adsorption/removal of Methyl Orange (MO) dye from aqueous solution using a new hybrid organometallic-based material constructed via In-Situ polymerization of Zinc-building units connected by coordination bonds to 4,4'-Carbonyldiphthalic acid (H4CDPA) as flexible multidentate organic ligand under solvothermal conditions with an amount of Maghnite-H+, an acid-exchanged montmorillonite clay to obtain Zn-CDP/Mag-H+ extremely stable thermally with an onset temperature of degradation upper to 460°C as shown by Thermogravimetric Analysis (TGA). The structure of this material is confirmed by Fourier Transform Infrared spectroscopy (FT-IR) and X-Ray Diffraction (XRD). The effect of different parameters such as adsorbent mass, initial dye concentration, contact time and pH solution on the adsorption capacity of this material is investigated using UV-visible spectroscopy. The kinetic study shows that the adsorption process of MO is very fast and well described by the pseudo-second-order model. The adsorption isotherms of the adsorbent/adsorbate systems are in agreement with the Langmuir equation showing an adsorption capacity of 147.05 mg/g for this material. The thermodynamic parameters calculated at various temperature indicate that MO adsorption on Zn-CDP/Mag-H+ is an endothermic reaction (∆H° > 0) and spontaneous (∆G° < 0) process.
- Preparation of Bio-Sensor with Nanofibers of glucose
oxidase/chitosan/graphene oxide for Detection of Glucose
Abstract: In this paper, a glassy carbon electrode (GCE) was modified with glucose oxidase (GOx)/chitosan (CS)/graphene oxide (GO) nanofibers for the detection of glucose via the electrospinning method. To do this, GOx was trapped among the two CS/GO nanofibers layers. Concerning electrochemical properties and producing conditions, the optimum amounts for GOx and GO in the deposited layer were 20 mg/mL and 20 % w/w, respectively. An investigation on the effects of pH, time of oxygen dissolving in the test solution, and scan rate on electrochemical behavior revealed that the peak current increased with increasing the oxygen dissolving time up to 20 min and scan rate values. However, the redox processes showed more symmetric anodic and cathodic structures at slow scan rates. Also, the highest current was obtained at a pH of 7.4. The result showed that the electrochemical process of GOx occurs through a two-proton and two-electron transformation. Additionally, the sensor exhibited excellent reproducibility and stability properties. It was concluded that the use of nanofibrous structure and the immobilization of the glucose oxidase among the two CS/GO nanofibers layers enhanced the electrochemical properties significantly due to penetration of water-soluble glucose molecules in the porous nanofiber layers, which helped efficiently catalyze the oxidation of glucose and facile direct electron transfer for GOx. The resultant modified electrodes exhibited a high sensitivity of 1006.86 μA/mMcm2 and a low detection limit of 0.02 mM with a wide linear range of 0.05–20 mM.
- Chitosan Nanoparticle - Montmorillonite - Titanium dioxide Nanocomposites:
Synthesis, Characterization and Antimicrobial Activity
Abstract: In recent years, a strong interest has emerged in hybrid composites and their potential uses, especially in Chitosan Nanoparticle – Montmorillonite - titanium dioxide - (CSNP – MMT - TiO2) composites, which have interesting technological properties and applications. Using the Precipitation Method, Chitosan Nanoparticle with TiO2 Nanocomposite (CSNP – MMT - TiO2 Nanocomposite) was created. Analysis using scanning electron microscopy (SEM) revealed that the modified TiO2 Nanocomposite was successfully dispersed into the Chitosan matrix, and that the roughness of the Chitosan Nanoparticle - MMT- TiO2 Nanocomposites were significantly reduced. Moreover, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses indicated that the Chitosan interacted with TiO2 Nanocomposite and possessed good compatibility, while a Thermogravimetric analysis (TGA) of the thermal properties showed that the Chitosan-MMT-TiO2 Nanocomposites with 0.05% TiO2 Nanocomposite concentration had the best thermal stability. The Chitosan- MMT-TiO2 Nanocomposite exhibited an inhibitory effect on the growth of gram-positive and gram-negative microorganisms.
- Exergy, Exergoeconomic and Exergoenvironmental Analysis in Natural Gas
Liquid Recovery Process
Abstract: In this work, the real case study of the energy quality of the natural gas liquid recovery plant 800 is evaluated through exergy, exergy economy and exergy environmental methods. The corresponding simulation is carried out using Aspen HYSYS V10 software and Matlab. Evaluate energy consumption, environmental impact, and economics of inefficient equipment through sensitivity analysis. The results of the exergy analysis show that the compressor (K103) and the heat exchanger (E101) with the highest exergy destruction are 510 and 629 kw respectively. Improving the performance of these equipment can reduce exergy destruction and increase exergy efficiency. Furthermore, the results indicate that the main improvement priority belongs to the compressor (K103). According to the results of the exergoeconomic evaluation, the maximum value of the exergoeconomic factors belongs to the heat exchanger (E103). It should be replaced by a cheaper one. Furthermore, E100 and K102 have potential for economic improvement, due to their high exergy destruction and relative cost difference. Furthermore, their low values of exergoeconomic factors show dominance in the exergy-related cost part. Improving the performance of these devices will significantly reduce the overall cost rate by up to 40%. The results show that the main improvement priority based on the exergoeconomic concept belongs to the compressor (K102). The highest value of the exergoenvironmental factor belongs to the heat exchanger (E-103) by 99%. This shows its high LCA environmental impact. Optimizing the operation and maintenance parameters of the equipment will reduce the overall impact rate by up to 97%. Environmental results show that E101 and P100 have potential for improvement. Improving the performance of these devices will significantly reduce the overall environmental impact by up to 40%. Furthermore, the main priority for improvements based on the exergoenvironmental concept belongs to the heat exchanger (E101).
- Effect of fin-shaped electrodes on flow mixing and pressure drop in an
electroosmotic micromixer
Abstract: Production of a homogeneous solution is of great interest for lab-on-a-chip (LOC) applications. Since the fluid flow in microchannels is laminar, the LOC devices have low mixing efficiency in passive mixers. The present study proposes a novel electroosmotic micromixer in which the electrodes have a fin-shaped structure in the mixing chamber. In other words, the combined effect of obstacle and electro-osmosis is evaluated. The effect of various parameters such as electrode angle, electrode height, inlet velocity, alternating current, and frequency on mixing index and pressure drop is investigated. Vortices are formed around the electrodes due to the applied electric field and their fin-shaped structure. It is revealed that the mixing index is an increasing function of applied voltage. The results demonstrate that there is an optimal value for the parameters, including frequency, electrode height, inlet velocity, and electrode angle. An increase in the mixing efficiency is accompanied by an enhancement in the pressure drop. It is revealed that the maximum efficiency is achieved when the electrode height is 5 μm and electrode angle is 60°. The coefficient of performance of the proposed micromixer is more than that of the reference mixer when electrode height is 2.5 μm and electrode angle is 90°.
- Nanocellulose Preparation from Sugarcane Bagasse and Its Application for
Paper Sizing
Abstract: The goal of this study was to fully utilize sugarcane bagasse, an abundant residue from the Vietnamese sugar industry that is also known as a potential source of lignocellulose. The biomass material was used as a raw material to produce cellulose pulp followed by a hydrogen peroxide bleaching process. On the one hand, the unbleached cellulose pulp was used to make paper sheets with basis weights of around 100 g/m2. The bleached cellulose, on the other hand, was chemically and mechanically transformed into nanocellulose via a limited hydrolysis procedure. The obtained nanocellulose possessed high crystallinity of 80.11% and was used for paper sizing to improve mechanical and barrier properties of the paper. The ability of sugarcane bagasse nanocellulose-coated paper sheets to produce biodegradable containers for food and beverage applications was investigated.
- Preparation and characterization of cellulose acetate microencapsulated
n-octadecane for thermal regulation applications
Abstract: In this research, a systematic study was carried out to prepare microcapsules with cellulose acetate as a shell polymer and n-octadecane as a core material with phase separation technique. This study aimed to investigate and clarify conditions for optimal morphology and behavior of these microcapsules for phase change materials (PCMs). Optimal core-shell weight ratio, polymer molecular weight and emulsification method were investigated. Using cellulose acetate with higher molecular weight (52,000 g/mol) and core-to-shell weight ratio of 2:1, microcapsules with a high encapsulation efficiency of 86.7%, melting and crystallization enthalpies of 132.33 (J/g) and 91.24 (J/g) were obtained. It was also observed that optimal method for preparation of primary emulsion phase was via magnetic stirring in comparison with ultra-sonication (40.9%). Average particle size distribution of microcapsules was 20.48 μm, with average shell thickness of 0.777 μm. The method used in this study was simple, fast and low cost effective. With an easy to scale-up feature, not requiring high temperatures or phase change starters, this novel microencapsulated PCMs are ideal for industrial use.
- Effect of fruit thickness on microwave drying characteristics of Myrtus
communis L.
Abstract: Myrtus communis L. (Myrtle) is an evergreen shrub and its fruit is used in traditional medicine in hypoglycemic, oral, and stomach diseases therapy. To the best of our knowledge there is no report on microwave drying of it. Therefore, this study is aimed to evaluate the effect of microwave power and fruit thickness on drying kinetics, effective moisture diffusivity, activation energy, specific energy consumption, and quality characteristics of Myrtus communis L.. Thus, four thickness (5, 7, 9, and 11 mm in diameter) of the fruit were dried at microwave power levels of 450, 600, and 750 W. The kinetics study revealed that the Midilli et al. model exhibited the best microwave drying behavior of the samples. Moreover, increasing microwave power and decreasing fruit thickness resulted in a substantial (P<0.05) reduction in drying time and an increase in drying rate. Fruit thickness also showed a significant effect (P<0.05) on effective moisture diffusivity and specific energy consumption, which ranged from 0.453×10-7 to 8.91×10-7 (m2/s) and 6.98 to 18.13 (MJ/kg water), respectively. In addition, the less fruit thickness, the more moisture diffusivity and the less activation energy. The calculated activation energies were in the range of 11.46 to 21.76 (W/g). Moreover, as the thickness of the fruit was reduced and the microwave power was increased, the shrinkage ratio of the samples was reduced and their rehydration abilities were enhanced. Finally, it was determined that a microwave power of 750 W and a fruit thickness of 5 mm made better results in terms of quantity and quality parameters.
- Response surface optimization of cupcake formula fortified with date seed
powder
Abstract: Recently the demand for dietary fiber-enriched foods has increased due to consumers' interest in nutritional and health benefits of functional foods. Date seed powder (DSP) is rich in dietary fiber and other nutrients such as minerals, antioxidants, unsaturated fatty acids, amino acids, and tocopherols. It is applicable as a cheap and valuable source to produce functional foods. In this study, DSP was added to the cupcake formulation at 5 levels (0.0, 2.5, 5.0, 7.5, and 10.0%), and the effect of this substitution on the physical, chemical, microbial and sensory properties of the final product were investigated during 28 days of storage at 4 °C. Based on the results, adding DSP to the cake formula significantly increased the amount of fat and fiber of the cake. Substituting wheat flour with DSP increased total phenolic compounds and moisture content of enriched cakes compared to the control. Furthermore, the peroxide, para-anisidine, and stiffness of fortified cakes were more than the control at all storage times. Adding DSP to the cake reduced the specific volume, L* and b* of crust and crumb. The highest overall acceptance of fortified cakes with DSP was with 2.5% DSP. According to the response surface models, the optimal quality of cakes was observed at the DSP ratio of 3.6 % and 0 days after preparation. Results were demonstrated that DSP could be used as dietary fiber supplement for cake enrichment.
- Eco-friendly Synthesis of benzyl
4-(((4-bromophenyl)sulfonamido)methyl)cyclohexane-1-carboxylate; Physical
and Biological Evaluation
Abstract: Primary objective of medicinal chemistry is the discovery of new compounds, beneficial to human and other living beings. As with passage of time, drug resistance is increasing with good pace, so synthesis of new drugs is of much importance. Keeping in view the importance of new drugs, our research group is engaged in designing and synthesizing new molecules with useful applications in the field of medicinal chemistry. This project is continuation of our previous work and here we synthesized new ester of sulfonamide. The structure was confirmed with XRD technique and in order to compare its different parameters (experiment), density function theory (DFT) studies were conducted using B3LYP. The structure was optimized and a very close similarity between theoretical and experimental studies has been observed. The biological application in a sense of antibacterial and enzyme inhibition (AChE and BChE) was also studied. Six bacterial strains were used and the synthesized ester has comparable results to standard drugs. The docking results are in a good agreement with the experimental outcomes of the enzyme inhibition.
- Modeling of a Batch Catalytic Reactive Distillation Process using
Multi-scale Approach of Pore Diffusion and Non-equilibrium Rate Based
Model
Abstract: Reactive distillation is carried out to produce methyl acetate from acetic acid and methanol using Indion180 as a solid ion-exchange resin catalyst in a simple distillation apparatus. Unlike the reboiler-column combination, a simple distillation apparatus is used to conduct reactive distillation where the vapors are condensed and collected as the catalytic reaction is proceeding in the reboiler flask. The aim is to quantitatively measure the distillate’s purity in terms of the methyl acetate’s mole fraction in it. The composition of instantaneous distillate, cumulative distillate and that of the reactant mixture in reboiler are measured continuously. The temperature in the reboiler as well as the electrical energy supplied to it is also measured as function of time. A non-equilibrium evaporation rate based model is proposed to predict the kinetics of the distillate and reboiler composition as well as the temperature. The reaction rate of the solid catalyzed esterification process is modeled as per pore diffusion model for heterogeneous part as well as homogeneous reaction. No previous studies are available with this concept of reaction kinetics in combination with evaporation rate for reactive distillation. The experiment is conducted in simple distillation mode with nearly a constant heat input rate and developed a mathematical model for the obtained distillate composition. The overall model of reactive distillation is validated with the help of a very few adjustable parameters found by minimizing the error between experimental data and model prediction.
- Catalytic activity of synthesized NiMo catalysts on walnut shell activated
carbon for heavy naphtha hydrotreating
Abstract: Hydrotreating of heavy naphtha using highly active NiMo catalysts on walnut shell activated carbon (NiMo-WAC) nanocatalysts is a new technology for clean fuel production. In this research, pyrolysis of the walnut shell as a scalable, low-cost, and high-yield method was used to synthesize chemically activated carbon in the presence of ZnCl2, as activating agent. To enhance the catalytic conversion, walnut shell active carbon was functionalized with HCL, HNO3 and H2SO4 to prepare NiMo-WAC1, NiMo-WAC2 and NiMo-WAC3 respectively. These nanocatalysts were synthesized through incipient wetness impregnation method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, inductively coupled plasma-atomic emission spectroscopy (ICP), field emission scanning electron microscope (FESEM), Brunauer–Emmett–Teller (BET) surface area, temperature-programmed desorption (TPD) and temperature-programmed reduction (TPR) techniques. CHNS (Eager 300 for EA1112) was used to study elemental analysis of the walnut shell feedstock used for active carbon synthesis. Different operating parameters including temperature, pressure, LHSV and H2/feed (heavy naphtha) ratio for hydrodesulfurization (HDS) reaction were explored through evaluating NiMo-WAC nanocatalysts catalytic activity. HDS of heavy naphtha with 2491 ppm of sulfur in the operation condition of temperature: 290 °C, pressure: 30 bar, H2/oil: 100 NL L-1 and LHSV: 3.3 h-1 showed considerably higher activity of NiMo-WAC2 nanocatalyst, less than 10 ppm in the product, than NiMo-γAl2O3 as a commercial and reference catalyst, maximum 104 ppm in the product, and this is economically valuable.
- Cogeneration system of power, cooling, and hydrogen from geothermal
Energy: An Exergy approach
Abstract: Production systems have experienced rapid growth over the past few years. Based on geothermal energy, the present study explores a unique cogeneration system that includes a proton membrane electrolyzer, Rankine cycle, and water-ammonia absorption chiller. The model under study is designed to generate power and hydrogen, as well as cooling, and it is analyzed from an energy and exergy standpoint. For the desuperheater and the absorber, the maximum rate of exergy destruction of the Rankin cycle is 34% and 36%, respectively. Furthermore, a parametric analysis of the system was conducted, and the cogeneration system was optimized from three perspectives: turbine production power, energy efficiency, and exergy. On the basis of turbine inlet and outlet pressure, turbine power, energy efficiency, and system efficiency are optimized. Moreover, the optimization calculations made from the perspective of turbine production power show that production power values are 101 kW, hydrogen production is 4.24 liters per second, system energy efficiency is 82.3%, and the amount of heat absorbed in the evaporator is 57.6 kW.
- An energy storage system utilization for performance enhancement of wind
catcher cooling
Abstract: High peaks of electrical energy usage during hot days of summer, has become an issue for the power supply systems causing regional power outages. Cooling demand is the main reason of such energy load, which is majorly supplied by the electricity. It is possible to use the night cold air for the day time cooling. The energy storage is necessary for usage of this night cold energy. The night ambient temperature is usually not cold enough to provide the required low temperature heat transfer fluid flow and also the day time cooling demand is usually high. A novel system where a storage unit is connected to a wind catcher has investigated in this study. The results showed that this new system, covers the above mentioned problems. According to the final results, 12.8 kWh of cold energy was stored in the energy storage unit, presenting 64 % of the energy storage efficiency and 6h 3m of the charging required time during the night. It was also revealed that, the energy storage unit thermal performance, is highly relevant to the inlet temperature, where 5 ̊ C decrease of the inlet temperature, increased the stored energy by 17% and decreased the charging required time by 1h 33m.
- Optimization of extraction conditions by ultrasound-assist on the ratio of
flavonoids, anthocyanins content and antioxidant and antimicrobial
activity of Punica granatum Var. Pleniflora (Persian Golnar) extract
Abstract: The aim of this study was to investigate the effect of type of solvent (1: ethanol and 2: water), time (3, 6, 9 min), and power (100, 200, 300 W) of ultrasound-assist on the extraction rate of flavonoids, anthocyanins, Ic50 as well as antimicrobial effect of the extract of Punica granatum. Var. Pleniflora (PGP). In order to designs of treatments, analysis, and optimization of dependent variable the full factorial design used. The result of multiple optimization of independent variables revealed that the highest amount of flavonoids in (PGP) extract (9.0502 mg/ml) and amount of anthocyanin (5.3669 Μmol/g) and the lowest Ic50 value or the highest rate of free radical scavenging in (PGP) (8.0452 mg/ml) with 88.97% desirability at were observed at 300 w for 9 min by using methanol as solvent. The highest mean values of minimum inhibitory concentration (MIC) and Minimum Bactericidal Concentration (MBC) of (PGP) extract obtained by ultrasound pretreatment were 625 and 3750 μg/ml respectively against Clostridium perfringens. The optimized predicted treatment by ultrasound pretreatment had greater antimicrobial effect on Staphylococcus aureus with the largest diameter of growth inhibition zone (14 mm) compared to E. coli and C. perfringens. The results showed that the extract obtained from (PGP) could be introduced as an antioxidant source in marketable foods.
- Determination of diphenylamine residue in fruit samples using dispersive
liquid–liquid microextraction coupled with ion mobility spectrometry
Abstract: In this study, a simple, fast and inexpensive method is introduced to extract and determine remaining diphenylamine (DPA) in fruit samples by the combination of dispersive liquid-liquid microextraction (DLLME) and ion mobility spectrometry (IMS). The main parameters such as the type and volume of extraction solvent, volume of dispersive solvent, salt addition, centrifugation time and sample pH that affected the extraction efficiency were evaluated by performing single-factor variable experiments. Chlorobenzene was selected as extraction solvent, which dispersed into samples by methanol as the dispersive solvent. In the optimized experimental conditions, the suggested technique showed good linearity in the range of 25-550 µg/ Lwith the correlation coefficient (R2) 0.997. The detection limits were obtained based on S/N of 3 as 7.5 µg L-1in the standard solution and 17µg/ kg in apple and pear samples. The repeatability and reproducibility of the method expressed as intraday (n=5) and interday (n=3) relative standard deviations were 6.0 and 7.5%, respectively at a concentration level of 150 µg/ L DPA, and the enrichment factor was 36.0. Analysis of fruit samples for measurement of DPA showed that the introduced method has great potential to extract and determine the DPA in real samples.
- Green sonochemical synthesis of technical fenitrothion using protic ionic
liquid
Abstract: In this manuscript, a new environmental-friendly method for the synthesis of technical Fenitrothion offered. Apart from using ionic liquid as the innocuous and recoverable solvent, this methodology offers sonochemical-assisted synthesis. Technical Fenitrothion has obtained from the reaction of 3-methyl-4-nitrophenol as a critical intermediate in this green method. According to this methodology, m-cresol is nitrated by ferric nitrate as the nitrating agent in the presence of triethyl ammonium nitrate ionic liquid as a recoverable protic solvent under ultrasonic irradiation, in short reaction time and high yield. Ionic liquid caused more para selectivity of nitration by steric hindrance through hydrogen bond formation with phenolic oxygen, which inhibited ortho substitution of the aromatic ring, and 4-isomer obtained as the major product. The developed process provided task-specific ionic liquid preparation from by-products and the possibility of recycling the ionic liquid for five consecutive runs, which has the benefit of eliminating waste products generated out of this procedure following green chemistry principles.
- Removal of Zinc (II) ions by Wheat Bran and Coffee Waste as Low Cost
Biosorbents
Abstract: In this paper wheat bran and coffee waste without any chemical treatment are used as low cost biosorbents for removal of zinc ions from aqueous solution. Parameters such as: contact time, adsorbent dose, initial concentration, and pH were studied. To describe adsorption equilibrium, Langmuir and Freundlich isotherms were used. Experimental results confirm that the adsorption of zinc ions on coffee waste fits well with the Langmuir isotherm while Freundlich isotherm is a better fit for wheat bran. Our result shows that, from the Langmuir model, maximum capacity of adsorbed zinc ions was higher for wheat bran (qmax= 9.01 mg/g) than coffee waste (qmax= 6.41 mg/g). The thermodynamic parameters, enthalpy (ΔHo), entropy (ΔSo) and Gibbs free energy (ΔGo), provide that the adsorption process is exothermic, spontaneous, favorable for two biosorbents used. The structure of both biosorbents was analyzed by FTIR spectra and pH of the point zero charge (pHPZC).
- Vapor-Liquid Equilibrium of Binary Systems Containing Cyano-based Ionic
Liquids and CO2: SAFT-γ GC EoS Modeling
Abstract: The unusual thermodynamic behavior of ionic liquid (IL)+CO2 mixtures has challenged their theoretical modeling. In this paper, a SAFT-γ equation-based group contribution method (SAFT-γ GC EoS) is used to predict the vapor-liquid equilibrium (VLE) of these mixtures. The binary systems containing CO2 and 1-butyl-3-methyl-imidazolium-thiocyanate ([bmim][SCN]), 1-ethyl-3-methylimidazolium dicyanamide ([emim][DCA]), 1-butyl-3-methylimidazolium dicyanamide ([bmim][DCA]), 1-hexyl-3-methylimidazolium dicyanamide ([hmim][DCA]), 1-ethyl-3-methylimidazolium tricyanomethanide ([emim][TCM]), 1-butyl-3-methylimidazolium tricyanomethanide ([bmim][TCM]) or 1-hexyl-3-methylimidazolium tetracyanoborate ([hmim][TCB]) are divided into the functional groups of CO2, cyano-based anion, CH2, CH3 and imidazolium-based cationic head. Some new SAFT-γ parameters are optimized at temperatures from 283.15 to 373.15 K and at pressures up to about 20 MPa. The observation of average error of 1.86% between experimental and estimated bubble pressures indicates the desirable performance of SAFT-γ GC EoS to predict the VLE of CO2+imidazolium-, cyano-based ionic liquid mixtures.
- Polyethylene glycol-graphene oxide modified with mesalazine; Synthesis,
characterization, and in-vitro drug releasing investigations
Abstract: ABSTRACT: Regarding the importance of targeted delivery of pharmacies, a novel drug delivery system was designed by mesalazine (Mes) anchoring on graphene oxide (GO) modified with polyethylene glycol (PEG) to obtain 2.6 mmol Mes on 1 g of GO-PEG. The new compound was produced through esterification reactions of GO with PEG and subsequent esterification with Mes. The nanodrug was characterized with common analyses methods including Raman, FT-IR, UV-Vis, Energy Dispersive X-ray, X-ray Diffraction, and Transmission Electron Microscopy. The in vitro Mes releasing from the composite was evaluated at two pHs of 3.5 and 7.4 for simulation of the gastric and intestine conditions. It was found that the compound is more stable in acidic media and slowly releases Mes at pH = 4. The reason for this phenomenon is considered as the ester bonds are produced in acidic media and is not been hydrolyzed in these conditions. The initial results for in vitro experiments indicated that the new drug would be a promising candidate for use in vivo.
- Introducing a new serpentine configuration of gas channels to enhance the
performance and reduce the water flooding in the PEMFC
Abstract: Proton-exchange membrane fuel cells consume hydrogen and air and have high efficiency and power density. The present study three-dimensionally investigates the performance of PEMFCs with different geometries under different operating conditions. The computational fluid dynamics approach was adopted to solve the governing equations. In CFD, the finite volume method is employed to discretize and solve equations. A serpentine gas injection channel and a parallel gas injection channel of the same size were examined. The proposed approach was validated by simulating the base model at 0.6 V and three reference current densities. The present work primarily sought to improve the performance of PEMFCs. Also, the concentration diagram indicated that the water concentration rose on the cathodic side, implying reasonable water transfer management was reasonable. Moreover, the oxygen concentration declined on the cathodic side. The serpentine model was found to have a higher current density and output power than the parallel model. Liquid water production was lower in the serpentine model than in the parallel model. This prevented immersion and fuel cell interruption. Water accumulation in the middle of the PEMFC with the parallel channel hindered uniform temperature and current density distributions. The parallel model underwent a lower pressure drop than the serpentine model. Therefore, lower power was required to pump the gases through the parallel channel. A rise in the reference current density reduced liquid water production and overpotential and improved the current density distribution and temperature distribution in both serpentine and parallel models.
- Design of a Solar Thermochemical Plant for Hydrogen Production
Abstract: This plant was developed that uses a sulfur-ammonia thermochemical water-splitting process for H2 production. Hydrogen is beneficial as a fuel in different industries and automobiles. Aspen plus was used for the simulation of hydrogen plant modeling. This process consists of electrolytic oxidation of ammonium sulfite and the thermal breakdown of potassium pyro sulfate and SO3 in the oxygen production half cycle. The reactions are carried out by solar thermal energy. The inlet stream is water, and the product streams are H2 and O2 gas. This research focuses on scrutinizing the economic strength in hydrogen production by electrolysis. During the research, it is clear that this type of study has great potential to reduce carbon emissions. That there is concluded economic potential for the electrolytic system. The model is for the full-scale operation that will produce approximately 1.3 lac kg H2 / day. It is equal to 370MW. Design specifications were placed in strategic areas of this model to aid in its conversions. Model convergence is complex because of various material, and energy recycle loops within the plant. The overall electricity needed to start the process is intramural from squandering heat. The thermal energy storage system will operate continuously without any shutdown. Three substitutes for hydrogen production from solar thermal energy have been inspected from both an efficiency and economic point of view. This observation shows that the possible alternative using solar energy with the help of thermochemical water splitting to manufacture H2 is the best one. The other methods consider the direct conversion of solar energy into electrical energy by Si cells and H2O analysis. The usage of solar energy to power a vapor cycle leads to the production of electrical energy.
- SYNTHESIS OF QCS-GLUTAMATE: A NEW SOURCE TO REMOVE HG(II) IONS FROM
WASTEWATER
Abstract: Here we report efficient biomass-based Hg (II) bioadsorbent. Quercus coccifera shell (QCS) was recycled and modified with glutamic acid by esterification as QCS-glutamate. After the FTIR, SEM and BET characterizations, related optimizations like the amount of adsorbent, initial concentration, temperature, and initial pH were studied to reach optimal adsorption efficiency. Then the adsorption and kinetic studies of the produced QCS-glutamate showed that Hg (II) was successfully adsorbed on QCS-glutamate with high adsorption maxima (qmax) and followed the Lagergren pseudo-second order reaction and Langmuir adsorption isotherm model (R2≥0.99). The maximum adsorption capacities (qmax) of QCS and QCS-glutamate were found as 35.71 and 70.42 mg/g, respectively while standard enthalpy (DHo) standard free energy (DGo) and standard entropy (DSo) were found as 34.31 kJ/mol, 87.58 kJ/mol and -178.74 j/mol K respectively. This finding suggests that a novel bioadsorbent QCS-glutamate is a cost-effective and promising bioadsorbent for the removal of Hg (II) ions from wastewaters.
- Autotuning of Decentralized and Centralized PID Control systems for
Non-Square Systems
Abstract: This paper presents a systematic procedure to obtain the decentralized and centralized PID controller settings for a non-square stable Multi-Input and Multi-Output (MIMO) system using simultaneous relay autotuning method with the incorporation of higher-order harmonics. In general, the assumption of filtering the higher-order harmonics will be acceptable when the system has the characteristics of a low-pass filter. However, higher-order harmonics have an impact on the controller parameter evaluation and it needs attention. Therefore, this research addresses the control of non-square stable MIMO systems in their original non-square form instead of squaring them by adding or deleting variables, and also the significance of higher-order harmonics in non-square stable MIMO systems is considered. To enhance the controller performance, higher-order harmonics are taken into consideration by observing the initial dynamics of the relay response. The decentralized and centralized control systems performances are explored by simulation on two different 3 inputs and 2 outputs models with different levels of interactions. For these models, simulation studies were carried out for both servo and regulatory operations. The performance of the centralized control system is improved for systems with interaction (relative gain is more than 1) by 18-41% for servo operation and 14-31% for regulatory operation. Also, the performance is improved for decentralized controllers for systems with a relative gain of less than one. The time integral analysis comparison between centralized and decentralized control schemes with the incorporation of higher-order harmonics using the simultaneous relay autotuning method is implemented. The effectiveness and performance of the proposed scheme are also analyzed even in the presence of robustness and the effect of measurement noise.
- Thermodynamic analysis of the effect of temperature on VOCs emission from
building materials
Abstract: This paper attempts to interpret the physical mechanism of temperature affecting the emission of VOCs from building materials from the viewpoint of thermodynamics. VOCs adsorbed onto building materials are assumed to form a condensed thermodynamic system. The kinetic energy of VOCs molecules takes values from zero to infinite. It is assumed that only VOCs molecules with the kinetic energy greater than the critical value can escape from building materials. Based on the Maxwell velocity distribution function, the correlation between the initial concentration of VOCs within building materials and temperature is derived. By use of Laplace transform technique and the theorem of initial value, the correlation between the initial emission factor and temperature is further presented on the basis of diffusion mechanism. The present thermodynamic model was validated through experimental data in literatures. Good agreement between the present thermodynamic model and experimental data is obtained. The present thermodynamic model can also explain the effect of temperature on the emission of other gases from materials.
- Synergy during pyrolysis of lignite and oil plant cake blends
Abstract: Although today’s fossil fuel reserves have been still considered as long term energy supply, biomass has received worldwide attention as a cheap and renewable energy source due to known global environmental impact of fossil fuel usage. Then co-processing of fossil fuels and biomasses to produce substitute liquid fuels is one option to appraise fossil fuel reserves for the economy.In this work, pyrolysis of Soma lignite and an oil plant cake, and their blends of varied proportions in the form of pellets were studied to elucidate main differences between the behaviour of these materials and their blends during fast thermal decomposition carried to convert them valuable products. A special vertical heating chamber, which enabled very fast heating, was used in the experiments conducted at 500-700oC temperature range. The results showed that these two materials mutually interacted when cake ratios of the pellets were below 50%. For blends with 75% cake, some interaction was observed only at 700oC. It is concluded that the interaction between two materials during pyrolysis is effected by outflow rates of volatiles into the sweeping gas.
- Influence of Fabrication Parameters on Thermo-Mechanical Characteristics
of Zea Natural Fiber Reinforced Polymer Composites
Abstract: Researchers have made remarkable achievements in natural fiber reinforced polymer composite materials based on their superior properties over other materials for usage in engineering fields from the last four decades. Agricultural-based residues are primarily available in various countries; Nowadays, these residues are used to reinforce fiber material for preparing composites. Zea is one of the agricultural residues-based fibers. The present effort investigates the thermal property, hardness, water absorption property, and dynamic behaviour of the composite material in the form of plates comprising polyester matrix reinforced with zea fibers. These properties are characterized from the composite plate possessing superior mechanical strength. The reinforcements are randomly oriented in the polyester matrix which are manufactured by compression moulding technique. The experimental results showed that the composite plate exhibited superior mechanical and thermal properties.
- Molecular Dynamics Simulation of Mixed Surfactants Adsorption on Graphene
Nano-sheets: Effects of Temperature, Electrolyte, and Alcohol
Abstract: An effective method for the preparation of stable dispersions of graphene is the direct exfoliation of graphene from graphite flakes in the aqueous solution of surfactants. Physical adsorption of surfactants on graphene surfaces is an important step in dispersing and stabilizing exfoliated graphene sheets in the aqueous medium. Dispersion of graphene with a mixture of surfactants is an effective way to obtain stable graphene sheets. The effect of synergism on a mixture of surfactants can reduce the total concentration of surfactants required for a particular application. The present study employed molecular dynamics simulation to investigate the adsorption of mixed cationic-rich and anionic-rich surfactants onto armchair graphene. We investigated the effects of temperature, electrolyte, and alcohol in the aqueous solution of surfactants on the adsorption process to understand the adsorption and self-assembly mechanism of surfactant mixtures on graphene surface and also to better optimize the graphene dispersion process. The simulation results suggested the improve stability of these systems through adding an electrolyte to the aqueous solution of the surfactants. The screening effect of electrolyte ions on the electrostatic repulsion between groups of charged heads of surfactants has led to a denser accumulation of surfactants on graphene and more favorable interactions between them. Increasing temperature, however, reduced the systems stability by desorbing the mixed surfactants from the graphene surface. Comparing the surfactant molecules and graphene in terms of energy levels of Lennard-Jones interactions with and without alcohol also showed increased interactions in the absence of alcohol, which helps improve the system stability.
- Synergistic effect between oleic imidazoline and 2-mercaptobenzimidazole
for increasing the corrosion inhibition performance in carbon steel
samples
Abstract: ABSTRACT: In this work, the corrosion rate and inhibition efficiency of oleic imidazoline and 2-mercaptobenzimidazole in 1 M HCl were studied on carbon steel samples. The corrosion efficiency of oleic imidazoline and 2-mercaptobenzimidazole at a concentration of 75 ppm was 85.8 and 82.9%, respectively. In addition, a mixture of these reagents at a ratio of 1:1 showed enhanced corrosion inhibition. The optimal concentration of the proposed mixture of reagents was 75 ppm. In this case, the inhibition efficiency was 97.8% (by weight loss method). The synergistic inhibition effect between the components of the proposed mixture was obtained 15.9%. Meanwhile, by increasing the temperature from 298.15 to 373.15 K, the corrosion inhibition of the reagents was not considerably decreased, which was associated with their complete adsorption on the surface of the carbon steel samples. The adsorption of inhibitors followed the Langmuir isotherm. The values of free energy of adsorption in the presence of the corrosion inhibitors ranged from -31.6 to -32.62 KJ/mol, which indicated both physisorption, and chemisorption features. Moreover, the results of electrochemical impedance spectroscopy and potentiodynamic polarization tests confirmed that the mixture of reagents at the ratio of 1:1 has a significantly higher inhibitory ability compared to each of the reagents alone. The used reagents behaved as a mixed-type inhibitor and affected both cathodic and anodic reactions.
- Optimization of a Bleaching Process for the Conversion of Sugar Beet Pulp
to α-cellulose with High Whiteness Index and Purity
Abstract: A large amount of sugar beet pulps are produced annually as waste which causes environmental pollution. However, the composition of sugar beet pulp indicates the possibility of producing several value-added products. In this study, high-quality α-cellulose was extracted from sugar beet pulp. The purity and optical properties of α-cellulose have a significant effect on its application in various industries, such as the production of napkins or a variety of papers. The bleaching step has a significant effect on the quality of cellulose. So bleaching conditions include the concentration of NaClO (4.5-1% w⁄w), temperature (25-60 °C), and time (15-45 minutes) were optimized based on response surface methodology. According to the results, good optical properties, low Kappa number, and high cellulose content (yield) could be achieved when the operating parameters were controlled. Severe bleaching conditions such as higher NaClO concentration or longer bleaching time caused cellulose oxidation and reduced efficiency. Optimal bleaching conditions for SBP were determined as 3.28% NaClO (w⁄w) at 25 °C for 45 minutes. These conditions were led to the production of α-cellulose with a 69.38% of whiteness index, a Kappa number of 1.02, and a yield of 23.16%. The structure of the samples was investigated by SEM and FTIR analysis. Therefore, the pulping and bleaching process has led to value-added products with industrial applications from sugar beet pulp.
- Lipophilicity and Biological Activity Study Of Several Caspofungin
Antifungal Drugs Using QSAR and Monte Carlo Methods
Abstract: QSAR investigations of Caspofungin derivatives were conducted using multiple linear regression (MLR), artificial neural network (ANN) and Monte Carlo Methods. The obtained results were compared and GA-ANN and ICA-MLR combinations showed the best performance according to its correlation coefficient (R2) and mean sum square errors (RMSE). The most important physicochemical and structural descriptors were presented and discussed. Monte Carlo method revealed that presence of double bond with branching, six-member cycle, absence of halogens, presence of sp2 carbon connected to branching, presence of Nitrogen and Oxygen atoms, absence of Sulphur and Phosphorus are the most important molecular features. The best Caspofungin derivative was exposed to reaction with Cu, Zn, Fe using B3lyp/6-311g/lanl2dz to investigate the stability of the formed complexes, from which the Zn complex was perceived to be the most stable one. It was concluded that QSAR study and Monte Carlo method can lead to a more comprehensive understanding of the relation between physico-chemical, structural or theoretical molecular descriptors of drugs to their biological activities and Lipophilicity.
- Investigation of chemical properties of eroded particles at four heights
with surface soil
Abstract: The chemical analysis of dust particles is essential to assess the potential impacts of dust on climate, environment, soil and health. The objective of this study is to compare the different chemical compositions of dust particles that they are collected at different heights above the soil surface and the eroded soils of the around Lake Urmia. To trap the dust particles, the BSNE samplers were used. 14 poles were installed inside 3 ha. area and 4 samplers were installed on each pole at 0.15, 0.5, 1 and 2 m heights above the soil surface. Chemical properties such as %T.N.V, %OC, ECe, pH, and SAR of collected particles was determined. The results of variance analysis and mean comparison illustrated that there was no significant difference between the eroded soil and the particles sampled from 15 cm height among all the investigated chemical parameters. It proves that the source of the moving particles at > 0.15 m is different from the eroded soil. By elevating height above the soil surface increased, the %T.N.V, ECe, and pH decreased but the SAR and %OC increased. There was a strong negative and significant correlation between the monthly rainfall and the ECe, %T.N.V, and SAR, except the %OC. The correlation between the speed of the strongest wind and the ECe, %OC, and SAR was positive and remarkable (P≤0.01). The pH was the only parameter that it was independent from all meteorological parameters in this research. Furthermore, the SAR was the most sensitive factor to the meteorological parameters.
- Retrofit design of CO2 compression and purification process using
intensification with cryogenic air separation unit
Abstract: The CO2 compression and purification unit (CPU) is an auto refrigeration system that works based on the Joule-Thomson effect, which requires high energy for compression and refrigeration. Therefore, optimization of this system has been an attractive research field in recent years. However, this system applied for capturing CO2 from oxy-fuel combustion (OFC) flue gases. The OFC refers to fuel combustion with approximate pure oxygen which in practice is usually produced from cryogenic air separation unit (ASU). In this study, CO2CPU system was redesigned based on oxygen stream effluent from cryogenic ASU. The results obtained by analyzing a sample of combustion gas showed that only the oxygen gas stream produced in the ASU unit, which is being prepared to enter the combustion chamber, is sufficient to condensate and refrigerate the CO2CPU system. The performance of the proposed design was compared with three recently proposed schemes for a given feed. The results showed that the proposed system can perform at lower operating pressure and needs significantly smaller heat-transfer area. In addition, integration of CPU and ASU decreased the number of compressors, and reduced the heat exchange area of cold-boxes by at least 79% and the compressor energy consumption by at least 29%. It also allowed the delivery of the final CO2 product in the subcooled liquid phase. Therefore, instead of the expensive compressor, the pump can be used to increase the pressure to transfer CO2. Furthermore, optimization and sensitivity analysis performed on this system using the response surface methodology (RSM), indicated that the inlet pressure and the temperature of the second separator had the most significant effect on this system.
- Clarification of apple juice with a scraped-surface membrane unit: the
effect of system parameters on process efficiency
Abstract: Apple juice can be clarified by ultrafiltration; however, fouling is a limiting factor against industrialization of the process. A scraped-surface membrane unit was designed and constructed to reduce fouling during membrane clarification of apple juice using polyether sulfone membrane with a pore size of 4 kDa. The effects of blade rotation speed (0, 600, 1400 and 2200 rpm), transmembrane pressure (0.5, 1 and 1.5 bar), feed flow rate (10, 15 and 20 mL/s) and distance between the blade and the membrane surface (2 and 5 mm) were evaluated on the permeate flux. The results revealed that increasing the blade rotation speed up to 600 rpm would increase the permeate flux, but further elevation of rotation did not affect the permeate flux. The optimized operating condition was obtained at low transmembrane pressure, feed flow rate, and short distance between the blade edge and the membrane surface. The study of the physicochemical properties of apple juice during clarification indicated that the designed system could reduce the turbidity of the juice by more than 99%. Other properties also changed to almost the same extent as in non-rotating systems.
- Comparing antibacterial properties of Ziziphora clinopodioides essential
oil in free and encapsulated states in minced beef contaminated with
Salmonella typhimurium
Abstract: : Salmonella, is among the most common foodborne pathogens that affect millions of people annually, sometimes with severe and fatal outcomes. In recent years, significant efforts have been made to develop natural antibacterial compounds, such as essential oils. Based on GC/MS analysis, Pulegone (33.10 %), Carvacrol (10.60 %), Piperitenone (9.33 %), Eucalyptol (8.01 %), γ-Terpineol (5.46 %) and L-Menthone (4.79 %) were the major components of phytochemicals of Ziziphora clinopodioides essential oil (ZEO). Encapsulation of ZEO using maltodextrin and gum arabic as wall in ratio of 1:1 with ZEO concentrations of 30 % (w/w) and 2.5 % (w/w) was done by spray drying method. The research results showed that, if the concentration of essential oil increased, the antimicrobial properties increased. The microbial population in the encapsulated ZEO treatment was lower than in the free ZEO treatment. The lowest inhibitory effect of ZEO was related to the concentration of 0.25 % (w/w) in the free state. The highest inhibitory effect of ZEO was related to the concentration of 1% (w/w) in the encapsulated state. The bacterial inhibitory property at the concentration of 0.5 % ZEO (w/w) in the free state was approximately equal to the concentration of 0.25 % ZEO (w/w) in the encapsulated state. The inhibitory properties of bacteria at concentration of 1 % (w/w) in the free state was better than the concentrations of 0.25 and 0.5 % (w/w) in the encapsulated state. Based on the results, formulation of ZEO in minced beef can prolong its shelf life and control microbial changes during storage at 4 oC. ZEO is insoluble in water, but a water-soluble microcapsule can be produced using this method. ZEO can be used as a natural and effective preservative for reducing pathogenic bacteria and increasing the shelf life of food.
- Optimization of Bitter Almond Oil (BAO) Extraction Conditions Using
Natural Enzymes and Ultrasound Waves
Abstract: The non-edible oils are typically applied for multiple uses especially biofuel production. But, finding new methods that can maximize the extraction of vegetable oils is urgently needed. In this work, natural enzymes present in kiwi fruit and ginger along with ultrasound waves method were used to extract bitter almond oil (BAO). Important factors affecting extraction were optimized using response surface methodology (Box-Behnken design). Under optimum conditions, the maximum extracted oil with an average of 62.1 wt.% oil/seed was extracted from the bitter almond kernel, which was only 0.87% less than the predicted value by the equation. The optimum conditions were: pH=4.74, Kiwi-Ginger juice to almond of 11.3 ml/g (22.6 ml ethanol), incubation temperature of 52 °C, ultrasonic power of 257 watts and ultrasonic time of 38 min. The results confirmed the validity of the model. The applied technique in this investigation is economically cost-effective and highly efficient which can be widely used in the edible oil industry due to the absence of toxic and hazardous substances.
- The Applicability of the Pseudolattice Approach for the Surface Tension of
Ionic Liquid Solutions
Abstract: Recently, the pseudolattice theory has been used to derive a simple linear correlation for prediction the surface tension of pure ionic liquids and their mixtures. That linear equation includes the parameters of coulomb interactions, and the short-range interaction between the ions. In this work, a new correlation was derived for the solutions of ionic liquids in molecular solvents. The obtained correlation, predicts that the difference between the experimental surface tension and an approximated surface tension without including ion-solvent interaction, (∆γ) is a function of -5/3 order of molar volume. ∆γ can be calculated by using the thermophysical experimental data. The linearity of the plots of ∆γ versus V-5/3 for mixtures of ionic liquids and solvents (alcohols and water) confirms the applicability of the pseudolattice theory for these systems. The slope of the obtained lines, Bmix, is a measure of ion-solvent interaction and is independent on the temperature and mole fraction. Finally, an empirical linear relationship between Bmix and pure ionic liquid properties was extracted for each solvent. The equation of the last linear correlation, is valuable for approximating B_mix and consequently, the surface tension of solutions at a varied range of temperatures and mole fraction.
- Modeling of the CO2 Separation Process from Acid Gas Feed into the Sulfur
Recovery Unit of Asaluyeh Phase 1 using Membrane
Abstract: In the sweetening process, acidic and sour gases, including CO2, are separated and transferred to the sulfur recycling unit. CO2 is one of the impurities in natural gas. In addition to its harmful effects on the environment, pipelines and refinery equipment, it also has many benefits in the field of oil, gas and petrochemicals. For this reason, the ability to Separation rate CO2 emissions by high-efficiency tools that are also economically viable is important. In this study, modeling this process before operation can be an important step in reducing the high cost of separation. In this research, the CO2 separation process using membranes has been modeled by MATLAB software, Then, the effect of CO2 separation on sulfur recovery rate was performed using sulfur recovery unit simulation by Promax software. As a result, the highest amount of sulfur recovery in the membrane process in Poly Ether Urethane Urea membrane at the level of 100000 m2 with a selectivity of 1.65 in which the amount of S2, S3, S4, S5, S6, S7 and S8 are 0.1897, 0.0191, 0.01615, 4.668, 291.3737, 121.5916 and 1821.651 kmol/h, respectively. In poly ether urethane urea membrane with selectivity of 1.65, the optimal point Obtained at a pressure of 35 kpa and a flow rate of 72.613 mol/s. The optimum point in the dimethyl silicon rubber membrane is achieved at a permeability pressure of 25 kpa and a flow rate of 98.4847 mol/s.
- Application of magnesium oxide nanoparticles for sunset yellow removal in
Abstract: In this research, the ability of magnesium oxide (MgO) nanoparticles adsorbent was studied for the removal of sunset yellow (SY) dye in an aqueous solution. Different techniques, including Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) was employed to identify the adsorbed dye. Adsorption experiments were carried out in a batch mode with varying pHs, MgO concentrations, initial dye concentrations, contact times, and temperatures. To study SY adsorption's efficiency on the surface of MgO nanoparticles, pseudo-first-order and second-order and intra-particle diffusion kinetic models were investigated. The pseudo-second-order kinetic model demonstrated a better fitting than other kinetic models (correlation coefficient: R2=0.99). The Freundlich model with an R2=0.93 value proved to fit with equilibrium data. In addition, thermodynamic parameters consisting of enthalpy, entropy, and activation energy were calculated too. It was noticed that the adsorption of SY on MgO was exothermic and spontaneous at low temperatures. The suggested adsorbent can be utilized for removing SY with an efficiency of more than 85%.
- Design of Industrial Water-based Polymerization Agitated Vessel by CFD
Simulation
Abstract: The agitated vessels are frequently used equipment in industries, especially in polymer processes. In the present work, the CFD simulation technique was used to study the effect of impeller shapes in the industrial scale water-based polymers agitated vessels to increase mixing efficiency. The VOF multiphase approach and RNG k-ε turbulent model were used to study the hydrodynamic behavior of fluids in the vessel. The simulations were done in four designs, including designs A, B, C and D. Designs A and B had three curved impellers with two 59° blades for each one and one straight impeller at the vessel bottom. Results showed that in designs A and B the gas phase entered the liquid (polymer) phase and caused foaming liquid. In design C, a geometrical modification was done by removing the top curved impeller, adding a blade for curved impellers and reducing of curved blade angle from 59° to 26°. Results showed that wide rotational zones were achieved (about 75% of liquid phase), and the liquid foaming problem was solved in design C. The modification of the bottom impeller in design D showed that the rotational zones cover about 95% of the entire liquid phase, which is the best performance compared to other designs. Also, the performance of design D was evaluated at the viscosity values, including 7 kg / m.s, 4 kg / m.s and 1 kg / m.s and mixing quality was validated at these values.
- Bacterial cellulose production enhancement in repeated static batch
culture of Acetobacter xylinum in bench-Scale
Abstract: Bacterial cellulose (BC) is commonly produced by a static batch culture, which is a time-consuming and low-yield process. Therefore, in this study, a new repeated static batch culture was developed with optimal conditions to reduce production time, increase production value and thus reduce BC production costs. First, by examining the volume to the surface ratio (depth) of the culture medium at 5 different levels and then the effect of cultivation time on production efficiency of BC, at the desired depth of 1.6 cm, 5.6 g/L of BC per week was obtained. Then, for more production enhancement of BC, a new repeated static batch culture was developed at the obtained optimal conditions in the previous step. Then, by investigating the effect of the number of feed addition cycles in the repeated-batch culture, the maximum BC production of 13.06 g/L was obtained at the optimum cycle number 4 (7 days per cycle) with aeration. The highest amount of produced BC at the end of the 5th cycle was 41.15 g in a culture volume of 3.5 L at 6 cm depth. Aeration at the rate of 0.1vvm increased BC production in all cycles and decreased overall production time. The highest BC concentration was 13.27 g/L at the end of the third cycle, and the maximum production was 44.2 g at the end of the 4th cycle. A comparison of shear stress and Young's modulus of BC sheets produced in different cycles of the repeated-batch static culture with and without aeration showed that increasing the number of cycles as opposed to aeration makes a significant difference in the mechanical properties of the produced BC sheets.
- Solvent-free nitration of toluene in presence of Nb2O5/SiO2 catalyst
Abstract: A series of Nb2O5/SiO2 catalysts with varying Nb2O5 loadings (5–25 wt%) were prepared by sol–gel technique. The catalytic activity of the materials was evaluated by nitration of toluene. Nb2O5/SiO2 catalyst shows good catalytic activity, selectivity and reusability for the nitration of Toluene. Under the optimal conditions, 86% of toluene conversion with 100% of selectivity to mono-nitrotoluene was achieved. Experiments were designed by Minitab software and the effect of reaction conditions on the amount of Meta isomer was analyzed. The optimal reaction condition for the lowest amount of Meta isomer also achieved by this software. The reusability of catalyst also has been studied in this work at the same operating condition and the catalyst was stable for four runs without the loss of its catalytic activity.
- Performance Assessment of Fuels TMEDA-DMAZ and Tonka250 with Liquid
Oxidizer AK27
Abstract: ABSTRACTTonka250 is a liquid fuel containing equal percentages of triethylamine and xylidine which has attracted the attention of space industries due to its favorable performance characteristics. Tonka250 has a low ignition delay (ID) time in presence of AK27 as a liquid oxidizer (about 24 ms) and can be used as a starter fuel in the engines working with a non-hypergolic combination of fuels and oxidizers. In recent years, due to the carcinogenic effect of Tonka250, novel fuels have been introduced for replacing it with high performance properties and non-carcinogenic effect. A combination of tetramethyl ethylene diamine (TMEDA) and dimethyl aminoethyl azide (DMAZ) can be a candidate for this purpose. According to the results obtained from the current research, the equal weight percentage of TMEDA and DMAZ has an ID time of 14 ms in reaction with AK27. The ID time was measured through cup test method with a fuel droplet into the liquid oxidizer. Density and density specific impulse of fuel TMEDA-DMAZ are close to those for Tonka250 while the values of specific impulse for fuel TMEDA-DMAZ is about 6 seconds more favorable than Tonka250 at the chamber and exit pressures 6.8 MPa and 0.1 MPa, respectively. Therefore, it seems that fuel TMEDA-DMAZ is a good candidate of replacement for Tonka250.
- Optimized Bioconversion of Soybean Meal Waste to Valued Biosurfactant by
Pseudomonas aeruginosa (PTCC 1074)
Abstract: Recently, microbial surface-active molecules called biosurfactants, have gained significant attention due to their structural diversity, biodegradability, low toxicity and several environmental and industrial applications. However, despite their advantages, they are not widely used because of high production costs, which can be overcome by bioconversion of agro-industrial wastes as low-cost substrates. The current study was aimed to overcome the challenges of biosurfactant production by bioconversion of soybean meal, as low-cost renewable substrate, and to optimize the significant parameters. Rhamnolipid biosurfactant was produced by Pseudomonas aeruginosa (PTCC 1074) using soybean meal under solid state fermentation and response surface methodology (RSM) by central composite design (CCD) was employed to optimize the significant parameters. The experimental value of biosurfactant production and Emulsification Index were 17.05 (g/Kg dry substrate) and 54 % respectively under the optimal conditions (temperature 33 ºC, Initial substrate moisture 80% and carbon-to-nitrogen ratio (C/N ratio) 54). Regression analysis with RSM resulted in quadratic models and the coefficient of determination (R2), adjusted R2, and predicted R2 were respectively calculated as 0.9767, 0.9557, and 0.9088, indicating that the model fitted the experimental data well. Increase of temperature from 25 to 34°C led to an increase of rhamnolipid production, which implies the significant influence of temperature. The results demonstrated that the production o