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  Subjects -> SCIENCES: COMPREHENSIVE WORKS (Total: 374 journals)
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Iranian Journal of Science and Technology, Transactions A : Science
Number of Followers: 0  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1028-6276 - ISSN (Online) 2364-1819
Published by Springer-Verlag Homepage  [2468 journals]
  • Wakefield Generation and Enhancement of Electron Energy to the Multi-GeV
           in a Magnetized Plasma

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      Abstract: The nonlinear interaction of an intense chirped laser pulse with transversely magnetized plasma is studied theoretically. The work described in this investigation is dealing with the characteristics of the wakefield generation by different chirping functions. Numerical results reveal that the amplitude and wavelength of the generated wakefield are highly influenced by the chirping constant and types of chirping function. Moreover, for the linear chirping function the positive chirping constant and for the nonlinear chirping functions the negative chirping constants excite larger wake amplitudes. In addition, it was found that by choosing a proper chirping constant for each chirping functions, one could obtain highly GeV electron energy gain. The maximum energy is obtained for the electron injected in the wakefield induced by the Exp and Linear chirped pulse. The maximum electron energy is about 2.5 GeV for the wake excited by the negative Exp chirp function. Further results revealed that the energy of the electron is significantly enhanced using an external transverse magnetic field.
      PubDate: 2023-06-01
       
  • Removal of Aqueous Pb2+ on Partially esterified Cellulose Obtained by
           Almond Shell Dissolution Using Deep Eutectic Solvent

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      Abstract: Microcrystalline cellulose (MCC) was isolated from the almond shell after its pretreatment with an acidic deep eutectic solvent (DES) of choline chloride/oxalic acid under microwave irradiation. The Fourier transform infrared spectroscopy analysis showed that the spectrum of the isolated (MCC) includes an additional peak at 1747.0 cm−1 which refers to the (C=O) esters and carboxylic peak. This indicates that the MCC surface has undergone simultaneous partial esterification during the isolation process. Owing to its favorable structural and morphological properties, the isolated MCC was successfully employed for the adsorption of aqueous Pb2+ ions with (50 mg/g) efficiency using a 3.0 g/L adsorbent dose at pH (6.5) and 20 °C. The adsorption was spontaneous near the ambient temperature, pH dependent, and exothermic. The Coulomb forces are the foremost adsorption driving force. The reusing of the spent DES and adsorbent for four successive rounds, affirmed their applicability on industrial scales.
      PubDate: 2023-06-01
       
  • On Refinements of Numerical Radius Inequalities

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      Abstract: In this paper, several numerical radius inequalities are developed for bounded linear operators defined on a Complex Hilbert space \(\mathcal {H}\) which refine some existing numerical radius inequalities.
      PubDate: 2023-06-01
       
  • On Mixed Steps-Collocation Schemes for Nonlinear Fractional Delay
           Differential Equations

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      Abstract: This research deals with the numerical solution of fractional differential equations with delay using the method of steps and shifted Legendre (Chebyshev) collocation method. This article presents a new formula for the fractional derivatives (in the Caputo sense) of shifted Legendre polynomials. With the help of this tool and previous work of the authors, efficient numerical schemes for solving nonlinear continuous fractional delay differential equations are proposed. The proposed schemes transform the nonlinear fractional delay differential equations to a non-delay one by employing the method of steps. Then, the approximate solution is expanded in terms of Legendre (Chebyshev) basis functions. Furthermore, the convergence analysis of the proposed schemes is provided. Several practical model examples are considered to illustrate the efficiency and accuracy of the proposed schemes.
      PubDate: 2023-06-01
       
  • $$^{3}\hbox{He} - \alpha $$ Radiative Capture Reaction by EFT

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      Abstract: We have investigated the \(^3\hbox{He} (\alpha ,\gamma ) ^7\hbox{Be}\) radiative capture reaction using the pionless Effective Field Theory (EFT). The amplitude, cross-section, and S-factor for the \(E_1\) and \(E_2\) transitions to the \(^{7}\hbox{Be}\) ground state have been computed using the Faddeev equation approach up to Next-to Leading Order in the astrophysical energy range. Our aim has been the study of Coulomb interaction effects and the contribution of EFT higher-order calculations in optimizing the results. The computed S-factor for the reaction agrees with experimental data and previous theoretical calculations.
      PubDate: 2023-06-01
       
  • Evaluation of Sodium Azide as a Chemical Mutagen in Developing
           Cold-Tolerant Quinoa (Chenopodium quinoa Willd.) Lines

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      Abstract: Quinoa (Chenopodium quinoa Willd.) is an allotetraploid grain crop belonging to the Amaranthaceae family. With a nutritionally well-balanced nature and rich oil, protein, vitamin, carbohydrate, and amino acid content, it has various health benefits. Hybridization programs to induce genetic variation are difficult processes in quinoa plants; however, the introduction of variations through mutation to obtain promising genotypes is much easier. In this research, quinoa cultivar Atlas seeds were exposed to different doses and application durations of sodium azide (NaN3) were cultivated in pots. The present findings revealed distinctive differences in all studied traits between native and mutant plants. NaN3 mutagenesis caused genetic variations that were categorized based on studied traits and RAPD data, which led to two distinct groups during M2. It was noted that 2 mM + 3 h NaN3 treatments had the greatest effects on genetic variations and germination parameters. Present findings were also confirmed by molecular analysis. This research will provide new insights into molecular breeding programs to be conducted to improve present quinoa genotypes and produce better genotypes.
      PubDate: 2023-06-01
       
  • Gymnosperm Foliage from the Lower Jurassic of Jirande Area, Western Alborz
           Mountain, North Iran

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      Abstract: This paper describes five gymnospermous macro-remains, including bennettitalean (Otozamites furoni), coniferalean (Pityophyllum longifolium and Stachyotaxus septentrionalis), ginkgoalean (Sphenobaiera gyron), and czekanowskialean (Phoenicopsis speciosa) leaves, from the Jirandeh area in the western Alborz, Iran. Materials were collected from a Lower Jurassic coal-bearing horizon within the Shemshak Group in the Jirande locality. The morphological characters of encountered gymnospermous remains, together with their palaeogeographical distribution and stratigraphical occurrences, are discussed herein. The species Sphenobaiera gyron is recorded here for the first time from Asia. Pityophyllum longifolium and Stachyotaxus septentrionalis are described for the first time in Iran. This is also the first report of Phoenicopsis speciosa from the western Alborz region. The upland environment under a subtropical to warm-temperate climate is suggested for the Lower Jurassic deposits in the Jirande area based on the occurrence of the encountered gymnospermous taxa.
      PubDate: 2023-06-01
       
  • Regularization of the Final Value Problem for the Time-Fractional
           Diffusion Equation

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      Abstract: We consider the backward problem of reconstructing the initial condition of a nonhomogeneous time-fractional diffusion equation from final measurements. The proposed method relies on the eigenfunction expansion of the forward solution and the Tikhonov regularization to control the instability of the underlying inverse problem. We establish stability results and we provide convergence rates under a priori and a posteriori parameter choice rules. The resulting algorithm is robust and computationally inexpensive. Two examples are included to illustrate the effectiveness and accuracy of the proposed method.
      PubDate: 2023-06-01
       
  • Determining Dry and Saturated Strength of Rocks by Using the Schmidt
           Hammer

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      Abstract: The main purpose of this research is to determine the dry and saturated strength of different sedimentary rocks including travertine, conglomerate, sandstone and limestone by using the Schmidt hammer test. To determine the strength of the studied rocks, comprehensive geotechnical tests including Brazilian tensile strength (BTS), block punch strength (BPS), point load strength (PLS) and uniaxial compressive strength (UCS) were performed in dry and saturated conditions on prepared standard specimens. Results show under BTS, BPS, PLS and UCS tests, the strength of the studied rocks after saturating is averagely reduced by 24.95, 31.80, 34.36 and 18.97%, respectively. Therefore, under saturated conditions, the strength of the studied samples reduced 27.52% averagely. The correlation between Schmidt rebound hardness and geotechnical properties in dry and saturated conditions was performed by simple regression analysis and experimental equations were obtained with a correlation coefficient from 0.65 to 0.93. For evaluating the performance of predictive models, some statistical parameters including RMSE, VAF, MAPE and PI were calculated and the 45° line and 95% confidence limit curves were also extracted for evaluating the validity of the concluded empirical equations. The results of this research demonstrate that the Schmidt hammer test is a reliable method for estimating the strength of rocks in dry and saturated conditions.
      PubDate: 2023-06-01
       
  • A Pragmatic Approach on Uncertainty Through Extropy as a Function of
           Extreme k-Records

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      Abstract: The whole study has been centred on extropy treated as function of k-records to carry out analysis on uncertainty in the distribution of a random variable. The study presents some interesting properties of extropy while considering k-records instead of the parent random variable. The extropy orderings with respect to k-records arising from the random variables have been discussed in detail in this work. The study also proposes an estimator for extropy based on k-records and presents an analysis on the performance of the proposed estimator. The preference for k-records over parent random variable and classical record values has been discussed through some examples and an illustration based on a real-life data set as well.
      PubDate: 2023-05-12
       
  • Fungal Bioremediation of the Plasticizer Hazardous Compound
           di-2-Ethylhexyl Phthalate (DEHP) in Urine and Blood Bags

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      Abstract: The hazardous compound di-2-ethylhexyl phthalate (DEHP) is widely used as polyvinyl chloride plasticizer. The present research studied the fungal biodegradation of DEHP contained in blood and urine bags. Soil-plate method was used for fungal isolation from heavily plastic polluted soil using Martin’s and Sabouraud’s agar media, where DEHP was the sole carbon source. Isolated fungal species were identified morphologically according to Moubasher (Soil Fungi in Qatar and Arab Countries University of Qatar, Qatar The Center for Scientific and Research, 1993) as Aspergillus nidulans, Aspergillus niger and Rhizopus nigricans. DEHP concentrations were determined in 1 g of soil, urine bags and blood bags to be 0.92, 2.5 and 2.6 g/l, respectively. Samples of both bags (as a sole carbon source) were artificially inoculated with the isolated fungi and incubated for 20 days. As the time increased, the growth increased where Rhizopus nigricans obtained the highest dry weight in urine bags after 20 days of incubation, while A. nidulans had the highest dry weight in blood bags. Also, a sharp declining of initial pH (6.8) reached 4.7 in urine bags with A. niger growth, while reached 2.5 after A. nidulans growth in blood bags. DEHP% decreased as time increased indicating a continuous DEHP utilization by the three fungal species. Aspergillus niger was the most DEHP degrading fungal species in both bags. Scanning electron microscope examination showed an uniform plastic network in both bags before fungal treatment. While, a microporous network was observed on the plastic surfaces in both bags after fungal treatment due to DEHP utilization. The most DEHP metabolizing fungal species were further identified molecularly using internal transcribed spacer primers to be Aspergillus niger and Aspergillus nidulans with accession numbers MZ832174 and MT919276, respectively.
      PubDate: 2023-05-10
       
  • Effect of Micro-Topography and Edaphic Factors on the Asafoetida Volatile
           Oil Components

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      Abstract: Asafoetida volatile oil components (AVOCs) are directly affected by microenvironmental changes. Here, this research aimed to investigate the AVOCs through gradients of micro-topography and edaphic factors in an arid area in central Iran (northern hemisphere) during two consecutive years. Soil and topography data were sampled simultaneously with oleo-gum-resin sampling using 20 plots placed in the area. Data were submitted to a PCA analysis. The AVOCs were significantly affected by both micro-topography and soil properties (P < 0.01). The components of carbonothioic dihydrazide and 1,3,6-0ctatriene, 3,7-dimethyl showed the most negative and positive relationship with the micro-elevation from 0 to 60 cm (R2 = 0.39, 0.44, respectively). Some components showed severe changes depending on the geographical direction, where the highest (42.2%) and lowest (25.1%) values of carbonothioic dihydrazide were obtained under the geographical direction of south and north, respectively. Also, nitrogen, phosphorus, organic matter and silt with R2 = 0.72, 0.52, 0.84 and 0.63, respectively, were positively correlated with some AVOCs, i.e., thiopropionamide and naphthalene, 1,2,3,5,6,8a-hexahy….
      PubDate: 2023-05-10
       
  • Determination of the Effective Blasting Region by Using Fragmentation
           Analysis: A Field Study

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      Abstract: Fragmentation, the most common method for assessing blast efficiency, provides significant benefits to post-blast operations. The most important parameter affecting fragmentation in blasting is geological formation characteristics. This study aimed to investigate the blasting efficiency on different geological units in the blasting area using WipFrag fragmentation analyses and to suggest ways to increase of blasting efficiency. With this aim, 30 blasts were observed in the Caldag raw material field of Adana Cement Turkish Inc., which has very heterogeneous geological features. The study field was examined by dividing it into 3 geological units as “limestone,” “clayey limestone,” and “clayey limestone + marl.” During the observations, scaled images were taken in each blasting area for in situ block size distribution before blasting and muckpile size distribution after blasting. In situ block size distribution and muckpile size distribution were evaluated using WipFrag software, and the fragmentation index of each blast was determined. One-way analysis of variance (ANOVA) was performed to determine the differences in the fragmentation index in the field. As a result of ANOVA analysis, there were differences between the geological units in terms of fragmentation index, and of the unit with the highest blasting efficiency was the “Clayey limestone + marl” unit.
      PubDate: 2023-05-06
       
  • Photocatalytic Degradation of Acidic and Basic Dye by ZnS and Tin-Doped
           ZnS Nanocatalysts

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      Abstract: Zinc sulphide (ZnS) nanomaterials were hydrothermally prepared and doped with 2% Tin (Sn). UV–Visible, X-ray Diffraction (XRD), Energy-Dispersive X-ray (EDX), Scanning Electron Microscopy (SEM), Fourier transform Infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA) were used to characterize the produced NPs. With successful doping, the band gap of ZnS nanomaterials decreased from 3.50 to 3.10 eV. Cubic crystal structure of ZnS and Sn-ZnS nanomaterials was shown by XRD with the average particle size of 16.30 and 18.62 nm, respectively. ZnS nanomaterials were found to have spherical shape, and no change in shape was noticed with Sn-doping. Using TGA analysis, 22.8% and 21.5% weight loss was observed in Zinc sulphide and Tin-doped ZnS nanocatalyst, respectively, at heating range of 40–600 °C revealing their stability to temperature. The synthesized nanoparticles were also used for the photodegradation of Coomassie Brilliant Blue G-250 (CBB G-250) and Basic Blue-3 (BB-3) dyes in aqueous solution. For photodegradation reaction using bare ZnS and Sn-doped ZnS nanomaterials, activation energies of 8.6 kJ/mol and 32.1 kJ/mol were calculated for ZnS and Sn-ZnS NPs, respectively. First-order reaction kinetics was followed by the photodegradation of both the dyes using these NPs. About 84% and 93% degradation was observed for CBB G-250 dye using bare and Sn-doped ZnS NPs at 240 min time interval while using the same nanoparticles for the degradation of BB-3 dye the degradation reached 83% and 95% at 360 min time, respectively. Low concentration (10 ppm) of dyes, maximum dosage (0.03 g) of the catalysts and increasing temperature up to 70 °C favoured the photocatalytic degradation. Per cent degradation of both the dyes was found higher at low pH(3.5). Both bare Zinc sulphide and Sn-doped Zinc sulphide nanomaterials could be recycled for the given dyes detoxification as shown by the recyclability of the used catalysts, but the performance of Sn-ZnS was higher as compared to pure ZnS. Results of antibacterial studies revealed that the synthesized NPs were more active against E. coli in all concentration as compared to others.
      PubDate: 2023-05-03
       
  • Decay Modes and Half-Life of 265–282Ds Isotopes

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      Abstract: The decay modes and half-lives of superheavy 265–282Ds isotopes have been investigated by using Relativistic Mean Field (RMF) model with density-dependent point-coupling and density-dependent meson-exchange functional. The potential energy surfaces as a funtion of deformation parameters ( \(\beta ,\gamma\) ) for the considered Ds nuclei have been obtained by using a triaxially deformed RMF model calculations for the investigation of their ground-state shapes and binding energies. The computed ground-state binding energy values of given Ds isotopes have been used for calculations of Q values of the alpha ( \(\alpha\) ), beta-plus/electron capture ( \(\beta ^{+}\) /EC), beta-minus ( \(\beta ^{-}\) ) and spontaneous fission (SF) decay modes. The dominant decay modes and half-lives of 265–282Ds isotopes have been predicted by using the computed Q-values and some empirical formulas. The results of the present study demonstrate that the 265–282Ds isotopes are well deformed, with prolate configuration in their ground-states. Our estimations for decay modes and half-lives are consistent with available experimental data.
      PubDate: 2023-04-27
       
  • Rock Strength and In Situ Stress Analysis for Wellbore Instability,¬†Fault
           Stress Regime Prediction, 3D Structural and Geomechanical Modelling in
           H-field¬†Offshore of Rio Del Rey Basin, Southwest Region, Cameroon

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      Abstract: The study involved the determination of strength parameters and in situ stresses in two wells pseudo-named H005 and H008 in a hydrocarbon field located offshore of Rio Del Rey basin. The work was aimed at revealing the stability of formation rocks and fault stress regimes associated with the study wells. The parameters determined employed only empirical correlations and tools since core samples were not available for laboratory experiments. The unconfined compressive strength for the two wells was relatively low varying from 1500 to 3300 psi in well H005 and from 1000 to 4000 psi in well H008. The friction angle varies from 21.0° to 23.0° in well H005 and from 21.0° to 27.0° in well H008. The results of the in situ stress analysis in well H005 indicate a reverse fault stress regime where maximum horizontal stress (SH) is greater than the minimum horizontal stress (Sh), which is in turn greater than the vertical stress (SV) in the shallow part of the well (1028.5–1249 m), while a normal fault stress regime where the vertical stress is greater than the two horizontal stresses was interpreted at a depth from 1250 to 1390 m. Unlike well H005, the entire depth of well H008 under interpretation revealed a normal fault stress regime. The outcome of the 3D geomechanical model closely agrees with the 1D model. It was concluded that the formation rocks are weak, and the wells are dominated by normal fault stress regimes.
      PubDate: 2023-04-24
       
  • Topologically Multiple Recurrence and Disjoint Topological Transitivity on
           Orlicz Spaces

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      Abstract: In this paper, we characterize topologically multiple recurrence for a single operator and sequences of operators on the Orlicz spaces of locally compact groups. These sequences of operators can be regarded as cosine operator functions. The sufficient conditions for sequences of operators to be disjoint topologically transitive and disjoint topologically mixing are given as well.
      PubDate: 2023-04-21
       
  • Magnetic Studies of Nanocomposites of La-Substituted Bismuth Ferrite and
           Zn-Substituted Lithium Ferrite

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      Abstract: La-substituted BiFeO3 and Zn-substituted Li0.5Fe2.5O4 (LZFO) were synthesized by sol-gel and auto-combustion techniques, respectively. Nanocomposites of these two phases were prepared using the conventional ceramic method. They were pressed into pellets at an applied pressure of 100 kg wt/cm2 and sintered at 600 °C. The presence of the two phases in the synthesized nanocomposites was confirmed from selected area electron diffraction spectra using transmission electron microscope in conjunction with X-ray diffraction spectra. The morphology and magnetic properties of the sintered nanocomposites were investigated. The morphology of the sintered nanocomposites was analyzed using scanning electron microscope, and the particle sizes varied from 316 to 106 nm with increasing LZFO content. Transmission electron microscopy images give the grain size data of the sintered nanocomposites. Magnetic properties of the sintered nanocomposites were studied as a function of LZFO content using a M–H hysteresis curve. The possible mechanisms for the obtained results are discussed.
      PubDate: 2023-04-20
       
  • A New Numerical Approach for Solving the Fractional Nonlinear
           Multi-pantograph Delay Differential Equations

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      Abstract: The numerical solution of the fractional nonlinear multi-pantograph delay differential equations is investigated by a new class of polynomials. These polynomials are equipped with an unknown auxiliary parameter a, which is obtained by using the collocation and least-squares methods. In this paper, the numerical solution of the fractional nonlinear multi-pantograph delay differential equation is displayed in the truncated series form. The existence and uniqueness of the solution and the error analysis are also investigated in this article. In four examples, the numerical results of the present method have been compared with other methods. For the first time, a-polynomials are used in this article to numerically solve the fractional nonlinear multi-pantograph delay differential equations, and accurate approximations have been displayed.
      PubDate: 2023-04-20
       
  • Heterologous Expression, Purification and Structural Characterization of
           Ribonuclease E from Mycobacterium smegmatis

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      Abstract: Rapid adaptations to various environmental changes are key to the survival of bacterial cells, which is mediated at the level of transcription initiation and RNA degradation/processing. Ribonuclease E (RNase E), an essential endoribonuclease gene in Mycobacterium species, is a key mediator in most reactions of RNA metabolism such as messenger RNA (mRNA), ribosomal RNA (rRNA) and transfer RNA (tRNA) processing and their degradation qualifying it as an important drug target. Here, we first report the cloning of full-length Mycobacterium smegmatis mc2155 (M. smegmatis) RNase E [MSMEG_4626] and its expression with isopropyl β-D-1-thiogalactopyranoside (IPTG) in Escherichia coli (E. coli) as a glutathione S-transferase (GST) fusion protein. The best expression of the recombinant protein was optimized with respect to different parameters, such as E. coli strains, temperature, IPTG concentrations and time points of induction. Despite the use of protease inhibitors, we observed low-molecular-weight degradation products along with full-length fusion proteins. Maximum expression of soluble and least degraded full-length RNase E was obtained at 32 °C/0.1-mM IPTG, further purified by affinity chromatography using glutathione agarose beads and confirmed by immunoblotting technique using anti-GST antibody. In silico characterization using multiple sequence alignment, homology modeling and docking studies revealed four amino acid residues, Asp613, Phe657, Ile662 and Glu688, in the catalytic domain of RNase E that are completely conserved in both E. coli and Mycobacterium species, also involved in RNA binding and might act as candidate drug targets to combat antibiotic-resistant mycobacterial diseases. Additionally, recombinant GST-RNase E protein can unravel the mechanism of RNA degradation/processing through protein–protein interaction studies.
      PubDate: 2023-04-20
       
 
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