for Journals by Title or ISSN for Articles by Keywords help
 Subjects -> ENGINEERING (Total: 2281 journals)     - CHEMICAL ENGINEERING (192 journals)    - CIVIL ENGINEERING (186 journals)    - ELECTRICAL ENGINEERING (102 journals)    - ENGINEERING (1203 journals)    - ENGINEERING MECHANICS AND MATERIALS (385 journals)    - HYDRAULIC ENGINEERING (55 journals)    - INDUSTRIAL ENGINEERING (68 journals)    - MECHANICAL ENGINEERING (90 journals) ENGINEERING (1203 journals)                  1 2 3 4 5 6 7 | Last
 Arabian Journal for Science and Engineering   [SJR: 0.345]   [H-I: 20]   [5 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1319-8025    Published by Springer-Verlag  [2353 journals]
• Carbonization of Silicon Nanoparticles via Ablation Induced by Femtosecond
Laser Pulses in Hexane
• Authors: Xi Yu; Shusaku Terakawa; Shunsuke Hayashi; Toru Asaka; Fumihiro Itoigawa; Shingo Ono; Jun Takayanagi
Pages: 4221 - 4226
Abstract: Abstract Silicon carbide (SiC) has been widely used in various technological applications, including power devices, light-receiving devices, and light-emitting devices. Several methods for fabricating SiC particles with nanometer dimensions have been reported, including carbo-thermal reduction of silica, chemical vapor deposition, laser pyrolysis, and microwave irradiation. To develop a new and simple method for fabricating SiC nanoparticles, we investigated the possibility of using femtosecond-laser ablation. In this paper, we report the formation of SiC nanoparticles by femtosecond-laser ablation on silicon immersed in hexane. By using a high-peak-power laser that can achieve extremely high temperatures and pressures on the silicon surface, SiC nanoparticles were successfully fabricated via ablation in hexane. In our experiments, femtosecond pulses from a Yb-fiber laser were used to irradiate to silicon single crystal. The laser was focused onto a spot on the silicon surface. After ablation, we evaluated the particles on the target substrate and particles in the irradiated hexane. Scanning electron microscopy revealed that the particles range in size from 100 to 400 nm. X-ray diffraction analysis indicated that the nanoparticles might be SiC. The characteristic X-ray photoelectron spectroscopy peaks of nanoparticles were Si-2p (100.1 eV) and C-1s (282.9 eV), which are identical to the characteristic peaks of SiC (John et al. in Handbook of X-ray photoelectron spectroscopy, Physical Electronics, Eden Prairie, 1995; Hijikata et al. in Appl Surf Sci 184:161–166, 2001; Shen et al. in Chem Phys Lett 375:177–184, 2003). We also used transmission electron microscopy and electron energy-loss spectroscopy to evaluate particles from the irradiated hexane. Such a simple method of fabricating SiC nanoparticles by femtosecond-laser ablation may open new possibilities in the development of growth techniques for SiC.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2619-7
Issue No: Vol. 42, No. 10 (2017)

• Computational Studies of Substituted Phenylboronic Acids in Common
Electrolyte Solvents
• Authors: Isaiah D. I. Ramaite; Teunis van Ree
Pages: 4227 - 4238
Abstract: Abstract Boronic acids and boronates are known as redox shuttles and film-forming additives. For example, 3,5-bis(trifluoromethyl)phenylboronic acid is reduced at a higher potential than that of PC-solvated $$\hbox {Li}^{+}$$ ion because of its lower LUMO energy level. Theoretical (molecular modelling) studies of the HOMO and LUMO energies of several phenylboronic acids and -boronates showed that the LUMO energies of all boronates were significantly lower than the LUMO energies of the commonly used carbonate electrolytes, both in vacuo and in solution, making them good candidates as electrolyte additives. The preferred conformation in vacuo and in solution of the boronate ester groups was ‘in–out’, with dihedral angles between the aromatic ring and boronate group varying between $$29.5{^{\circ }}$$ and $$33.6{^{\circ }}$$ . In contrast, the preferred conformations of the phenylboronic acids were found to be always coplanar and ‘out–out’, with dihedral angles close to $$0{^{\circ }}$$ . We speculated that back-bonding and intermolecular hydrogen bonding played a role. In this study, therefore, we investigated the role of intermolecular hydrogen bonding and solvation in this phenomenon, using HF and DFT methods.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2612-1
Issue No: Vol. 42, No. 10 (2017)

• Stepwise Synthesis of Graphene Oxide-Wrapped Magnetic Composite and Its
Application for the Removal of Pb(II)
• Authors: Zhongliang Hu; Shilin Qin; Zhi Huang; Yirong Zhu; Liujiang Xi; Zhaohui Li
Pages: 4239 - 4247
Abstract: Abstract Graphene oxide-wrapped magnetic composite (GO-W-MC) with core–shell structure was prepared stepwise and characterized by scanning electron microscopy, powder X-ray diffraction, Fourier transform infrared spectrometry, and vibrating sample magnetometer analysis. The preparation procedure included the following steps: synthesis of $$\hbox {Fe}_{3}\hbox {O}_{4}$$ nanoparticles by a solvothermal method, surface coating of $$\hbox {SiO}_{2}$$ and – $$\hbox {NH}_{2}$$ groups, and encapsulation of GO sheets via covalent bonding. The key factors affecting the morphology and the structure of GO-W-MC have been analyzed in detail, and the related formation processes have been revealed. It was found that the concentration of the amination agent and the pH value of the GO solution have pronounced effects on the morphology and the structure of GO-W-MC. The GO-W-MC prepared at the optimized process conditions possesses a stable structure in which GO sheets are firmly grafted on the surface of the magnetic particles via covalent bonding and exhibits high magnetization (55 emu/g). The effects of pH on the adsorption and the adsorption isotherm were also studied. The results indicated that the adsorption capacity of GO-W-MC increases with the pH until a value of 7.0, and the GO-W-MC has a high adsorption capacity ( $${q}_{\mathrm{m}} = 225.6\,\hbox {mg/g}$$ ) toward Pb(II) in aqueous solution, maintaining 80% adsorption capacity even after five adsorption–desorption cycles. This study could be of theoretical guidance for the synthesis of magnetic GO-based composites, with regard to optimization of process parameters, modification of structure, and performance enhancement.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2613-0
Issue No: Vol. 42, No. 10 (2017)

• Synthesis and Evaluation of Isoflavones as Potential Anti-inflammatory
Inhibitors
• Authors: Isaiah D. I. Ramaite; Musa D. Maluleke; Simon S. Mnyakeni-Moleele
Pages: 4263 - 4271
Abstract: Abstract A series of isoflavones was synthesized in high yields from 3-iodochromones via the Suzuki–Miyaura reaction. Selected isoflavones were then evaluated for potential anti-inflammatory and/or HIV reverse transcriptase inhibitory properties. Only 3-(4 $$'$$ -methoxyphenyl)-4H-chromen-4-one 4b, 3-(4 $$'$$ -chlorophenyl)-4H-chromen-4-one 4c and 3-(4 $$'$$ -bromophenyl)-4H-chromen-4-one 4d showed dose-dependent attenuation of LPS-induced nitrate production indicating potential anti-inflammatory activity. NO production was 1.21, 1.43 and 1.43  $$\upmu \hbox {M}$$ , respectively, even at the highest concentration of 50  $$\upmu \hbox {M}$$ tested. However, relative to the positive control these activities are weak. None of the screened compounds was found to exhibit significant reverse transcriptase inhibition at the highest concentration of 50  $$\upmu \hbox {M}$$ tested.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2614-z
Issue No: Vol. 42, No. 10 (2017)

• Semiconductor Property and Corrosion Behavior of Passive Film Formed on
Steel with Zinc Coating in 5% NaCl Solution
• Authors: Yi Xiao; Jianfeng Gu; Junxi Zhang
Pages: 4273 - 4280
Abstract: Abstract The initial stage of corrosion behavior and the semiconductor property of a passive film formed on steel with zinc coating were investigated in 5 wt.% NaCl solution using scanning electrochemical microscopy (SECM), electrochemical impedance spectroscopy (EIS), potential-capacitance measurement and the Mott–Schottky analysis method. The SECM test results reveal that the Faradic currents on the tip of the ultramicro electrode decreased with the extension of immersion time, suggesting that the coating was slowly degrading, and the water and ions gradually permeated into the coating. The tip current remained stable without obvious bursting and swelling, which revealed that no blister occurred inside the coating. EIS results also support the above conclusion, especially for long-term immersion. The potential-capacitance and Mott–Schottky analysis show that the water and ions gradually entered into the coating during the immersion process, while at the same time the coating showed the characteristics of n-type semiconductor. As the time elapsed, the capacitance value decreased and the thickness of the space charge layer declined. The decrease in the slope of the Mott–Schottky curves suggested the simultaneous increase of the carrier density, and the coating was degrading. SEM observation also exhibits an obvious coating degradation after immersion compared with the previous coating without immersion in solution.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2640-x
Issue No: Vol. 42, No. 10 (2017)

• $$\hbox {Mn}_{3}\hbox {O}_{4}$$ Mn 3 O 4 Nanosheet and GNS– $$\hbox {Mn}_{3}\hbox {O}_{4}$$ Mn 3 O 4 Composite as High-Performance Anode
Materials for Lithium-Ion Batteries
• Authors: Weiwei Sun; Zhiqiang Yu; Li-Ping Lv; Yi Xu; Hao Liu; Guoxiu Wang; Yong Wang
Pages: 4281 - 4289
Abstract: Abstract Nanostructured transitional metal oxides have received more and more attention as the electrode materials for lithium-ion batteries to achieve high specific capacity and good safety performance. In this paper, a graphene nanosheet-supported $$\hbox {Mn}_{3}\hbox {O}_{4}$$ nanoparticles ( $$\hbox {Mn}_{3}\hbox {O}_{4}$$ –GNS) composite, as well as $$\hbox {Mn}_{3}\hbox {O}_{4}$$ nanosheet, were synthesized via a facile hydrothermal method. The $$\hbox {Mn}_{3}\hbox {O}_{4}$$ –GNS composite exhibits good electrochemical performances with high reversible specific capacity (an initial charge capacity of 969 mAh $$\hbox {g}^{-1}$$ at 93.6 mA  $$\hbox {g}^{-1}$$ ), good cycling stability (a retained capacity of 646 mAh $$\hbox {g}^{-1}$$ after 60 cycles) and rate capability when used as the anode material for LIBs. The enhanced electrochemical performance could be attributed to the nanoscaled particles of $$\hbox {Mn}_{3}\hbox {O}_{4}$$ , the buffer and confine effects of graphene nanosheets (GNSs) and the distinctive synergistic effect between two components of GNS and metal oxides.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2611-2
Issue No: Vol. 42, No. 10 (2017)

• K-Doped Li-Rich Molybdenum-Based Oxide with Improved Electrochemical
Properties for Lithium-Ion Batteries
• Authors: Shishun Yu; Can Peng; Zhaohui Li; Lingjun Zhang; Qizhen Xiao; Gangtie Lei; Yanhuai Ding
Pages: 4291 - 4298
Abstract: Abstract Li-rich molybdenum-based oxide ( $$\hbox {Li}_{2}\hbox {MoO}_{3})$$ , which owns a layered structure similar to that of $$\hbox {Li}_{2}\hbox {MnO}_{3}$$ , has caused much attention as a kind of high-energy-density cathode material for Li-ion batteries. Although $$\hbox {Mo}^{4+}$$ in the [ $$\hbox {Li}\hbox {Mo}_{2}$$ ] slabs could be oxidized to $$\hbox {Mo}^{5+}/\hbox {Mo}^{6+ }$$ easily, the $$\hbox {Li}_{2}\hbox {MoO}_{3 }$$ might still suffer from a phase transformation from layered to disordered at a deeply charged state more than 4.4 V (vs. $$\hbox {Li}^{+}/\hbox {Li}$$ ) in the first cycle, resulting in fast capacity degradation. To resolve these issues, $$\hbox {K}^{+}$$ ion is chosen to dope into the $$\hbox {Li}_{2}\hbox {MoO}_{3}$$ crystal using a K-doped precursor $$\hbox {K}_{0.1}\hbox {MoO}_{3}$$ that prepared by a hydrothermal method. The as-prepared $$\hbox {Li}_{1.9}\hbox {K}_{0.1}\hbox {MoO}_{3}$$ sample showed nanobelt morphology and possessed a layered structure. Befitting from the chemical pre-insertion of $$\hbox {K}^{+}$$ , this doped sample exhibited a stable cycling life and an improved rate capability when operated over the potential range of 1.5–4.4 V (vs. $$\hbox {Li}^{+}/\hbox {Li}$$ ). The results suggest that chemical pre-insertion of $$\hbox {K}^{+}$$ is an effective approach to improve the electrochemical properties of the $$\hbox {Li}_{2}\hbox {MoO}_{3 }$$ cathode material.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2719-4
Issue No: Vol. 42, No. 10 (2017)

• Structural Features of Silica Coating Obtained from Sol Cooled to the
Temperature of Liquid Nitrogen
• Authors: I. A. Pronin; I. A. Averin; N. D. Yakushova; A. A. Karmanov; V. A. Moshnikov; M.-H. Ham; B. K. Cho; G. Korotcenkov
Pages: 4299 - 4305
Abstract: Abstract A new approach to controlling the structure of silica films formed by the sol–gel method is proposed. The models of formation of the silica coatings, obtained from the sol, cooled to the liquid nitrogen temperature, have been developed. It was found that as a result of this process, one can obtain aggregates consisting of spindle-shaped nanoparticles with sizes of the order of tens of nanometers, formed during the preparation of sol. The proposed model predicts aggregate sizes that depend on the synthesis conditions. The results obtained can be useful for the preparation of films with controlled degree of nanocrystallite’s agglomeration.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2804-8
Issue No: Vol. 42, No. 10 (2017)

• Poly(Vinyl Chloride) Doped by 2-(4-Isobutylphenyl)Propanoate Metal
Complexes: Enhanced Resistance to UV Irradiation
• Authors: Rafah Mohammed; Gamal A. El-Hiti; Ahmed Ahmed; Emad Yousif
Pages: 4307 - 4315
Abstract: Abstract The photostabilization of poly(vinyl chloride) (PVC) films in the presence of 2-(4-isobutylphenyl)propanoate metal complexes (0.5 wt%) was investigated at room temperature under ultraviolet radiation ( $$\lambda = 320 \hbox { nm}$$ ) for 300 h. The changes in various functional groups indices, viscosity average molecular weight and quantum yield of the chain scission of PVC films were monitored upon irradiation. The metal complexes used showed decreases in PVC films photodegradation. The quantum yield for the chain scission was measured exhibiting a range of $$2.054 \times 10^{-6}$$ and $$1.005 \times 10^{-7}$$ . The photostabilization of poly(vinyl chloride) in the presence of metal complexes was in the order $$\hbox {ZnL}_{2} (\hbox {H}_{2}\hbox {O})_{2}< \hbox {CdL}_{2} (\hbox {H}_{2}\hbox {O})_{2}<\hbox {CuL}_{2}< \hbox {SnL}_{2} (\hbox {H}_{2}\hbox {O})_{2}<\hbox {NiL}_{2} (\hbox {H}_{2}\hbox {O})_{2}$$ . The metal complexes can act as hydrogen chloride scavengers, UV absorbers, peroxide decomposers and also as radical scavengers to enhance PVC photostability.
PubDate: 2017-10-01
DOI: 10.1007/s13369-016-2323-z
Issue No: Vol. 42, No. 10 (2017)

• Solution-Processed ZnO-Based Low-Cost $$\hbox {CH}_{3} \hbox {NH}_{3} \hbox {PbI}_{3}$$ CH 3 NH 3 PbI 3 Solar Cells by Ambient Air, Hole
Transport Layer-Free Synthesis
• Authors: Muhammad Imran Ahmed; Zakir Hussain; Amir Khalid; Amir Habib
Pages: 4317 - 4325
Abstract: Abstract Organo-metallic lead halide-based solar cells have emerged as the main contenders for meeting the alternate energy needs of present times. Major costs associated with this technology are the requirement of controlled processing conditions and high cost of hole transport materials. Cost of this technology can be reduced by developing low-cost ambient air synthesis protocol for hole transport layer-free device architecture. We report here on methyl ammonium lead iodide-based solar cell employing zinc oxide as electron transport layer prepared under ambient conditions of high humidity of 50% without hole transport layer. Stabilized power conversion efficiency of 3.03% is achieved. This approach affords the possibility of simplified device geometry and cost effectiveness paving way for rapid commercialization.
PubDate: 2017-10-01
DOI: 10.1007/s13369-016-2339-4
Issue No: Vol. 42, No. 10 (2017)

• Assessing the Anticorrosion and Antifouling Performances of a Sol–Gel
Coating Mixed with Corrosion Inhibitors and Immobilised Bacterial
Endospores
• Authors: Rami Suleiman; Jeanette Gittens; Mazen Khaled; Thomas J. Smith; Robert Akid; Bassam El Ali; Amjad Khalil
Pages: 4327 - 4338
Abstract: Abstract The encapsulation of corrosion inhibitors in sol–gel coatings is a practical method for protecting mild steel against corrosion. Another recent approach involves the localization of a biologically active reagent close to the metal substrate. In this study, we have utilized the above two approaches in developing bacteria and inhibitor-doped sol–gel protective antifouling coatings on mild steel substrates. Molywhite $$^\mathrm{TM}$$ and Heucophos ZAPP $$^\mathrm{TM}$$ have been selected to be mixed with Paenibacillus polymyxa endospores within a base sol–gel coating composed of TEOS and METEOS and then applied on mild steel panels. The corrosion inhibition efficiency of the coatings was evaluated using electrochemical impedance spectroscopy and scanning electron microscopy techniques. After immersion in open seawater or marine estuarine water for 10 weeks, coatings containing endospores of P. polymyxa bacterial strain alone gave superior corrosion and antifouling protection than coatings containing corrosion inhibitors alone or corrosion inhibitors with endospores.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2419-0
Issue No: Vol. 42, No. 10 (2017)

• A Novel Intumescent Flame Retardant: Synthesis and Its Application for
Linear Low-Density Polyethylene
• Authors: Ghada Makhlouf; Mohamed Hassan; Mohamed Nour; Yasser Abdelmonem; Aksam Abdelkhalik
Pages: 4339 - 4349
Abstract: Abstract A novel intumescent flame retardant, melamine salt of pentaerythritol phosphate montmorillonite (MPPM), was synthesized and characterized by $$^{1}$$ H NMR, FTIR, and XRD. Its effect on the thermal stability and flammability properties of linear low-density polyethylene (LLDPE) was investigated. The thermogravimetric analysis data exhibited that MPPM enhanced the char formation and the thermal stability of LLDPE at high temperatures. The cone calorimeter results showed that addition of MPPM to LLDPE reduced greatly the peak of heat release rate, total heat release, mean mass loss rate, and fire growth rate index in all LLDPE composites. Moreover, MPPM increased the fire performance index of LLDPE and led to achieve V-0 rating in UL-94V test. The morphology, FTIR, and EDXS analysis for char residue after cone colorimeter test showed the formation of thermally stable char containing Al, Si, – $$\hbox {CH}_{2}$$ –, P–O, P–O–C, C–N, and C=N. This meant that MPPM was efficient in reducing the fire hazardous of LLDPE.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2443-0
Issue No: Vol. 42, No. 10 (2017)

• Synthesis and Characterization of Zinc Fluoroborate from Zinc Fluoride and
Boron by Mechanochemical Reaction
• Authors: Duygu Y. Aydın; Metin Gürü; Dilek Ipek; Dursun Özyürek
Pages: 4409 - 4416
Abstract: Abstract This paper deals with characterization and synthesis of zinc fluoroborate from zinc fluoride and boron by mechanochemical reaction. Zinc fluoroborate is widely used in high technological areas such as textile, chemical reaction, plating solution, and glass. In this study, zinc fluoroborate has been synthesized via high-energy ball milling method. The effect of reactant mol ratio (B/ $$\hbox {ZnF}_{2})$$ and ball milling period was investigated on the product yield. After completion of the reaction, the product in the reaction mixture (including excess reactant and side products) was purified by the extraction with water. The samples were characterized by FT-IR and $$\hbox {BF}_{4}^{-}$$ ion-selective electrode. SEM and EDX analyses were took place. Decomposition of sample was characterized by TG-DTA. The sample was sintered at 300– $$500\,{^{\circ }}\hbox {C}$$ to compare the data with TG-DTA. The results showed that decomposition of B–F bond started at $$300\,{^{\circ }}\hbox {C}$$ . As a result of these experiments, maximum yield was obtained at 0.8 molar ratio and 3000 min. of mechanochemical reaction duration with the use of ball milling. Eighty-three percentage pure zinc fluoroborate was produced by adding the purification step.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2559-2
Issue No: Vol. 42, No. 10 (2017)

• Enhancement of Defluoride Performance of the Spherical $$\hbox {FeOOH}/{\upgamma }\hbox {-Al}_{2}\hbox {O}_{3}$$ FeOOH / γ -Al 2 O 3
• Authors: Zhou Wang; Xiangqian Shen; Maoxiang Jing
Pages: 4417 - 4425
Abstract: Abstract Excess fluoride in drinking water hazarded people health, so we have undertaken to develop a nanoscale $$\hbox {FeOOH}/{\upgamma }\hbox {-Al}_{2}\hbox {O}_{3}$$ absorbent to remove fluoride in drinking water. The as-prepared nanoscale $$\hbox {FeOOH}/{\upgamma }\hbox {-Al}_{2}\hbox {O}_{3}$$ absorbent was characterized by transmission electron microscopy, surface area analyzer, and X-ray diffraction. Herein, we explored the effect of pH of solution, concentration of initial fluoride, contact time, and temperature on defluoride efficiency. The results showed the composite owned to further adherence to defluoride, compared to spherical and mesoporous alumina granules. The experiment data were fit with different models and assessed by regression coefficient $$(R^{2})$$ ; the pseudo-second-order model was used to explain the adsorption process. The adsorption mechanism can be explained by a proton shifting mechanism.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2520-4
Issue No: Vol. 42, No. 10 (2017)

• Synthesis of $$\hbox {Fe}_{3}$$ Fe 3 Al Intermetallic Compound by
Mechanical Alloying
• Authors: Deepankar Panda; Pallabi Bhuyan; Lailesh Kumar; Syed Nasimul Alam
Pages: 4427 - 4437
Abstract: Abstract In the present work, nanostructured $$\hbox {Fe}_{3}\hbox {Al}$$ intermetallic compound has been synthesized by mechanical alloying (MA) of $$\hbox {Fe}_{75}\hbox {Al}_{25}$$ powder milled for 40 h followed by heat treatment at $$1100\,{^{\circ}}\hbox {C}$$ for 2 h in Ar atmosphere. The structural evolution of the $$\hbox {Fe}_{75}\hbox {Al}_{25}$$ powder during MA and subsequent isothermal annealing was analyzed using X-ray diffraction (XRD). After 40 h of milling, a disordered Fe(Al) solid solution is formed. On annealing, the Fe(Al) solid solution undergoes an ordering transformation resulting in the formation of ordered $$\hbox {D0}_{3}$$ - $$\hbox {Fe}_{3}\hbox {Al}$$ . The presence of the (111) superlattice peak in the XRD plot of the annealed powder is a direct evidence of the ordered arrangements in the alloy. A shallow exothermic peak below $$600\,{^{\circ}}\hbox {C}$$ in the DSC plot of the 40-h milled powder also confirms the formation of ordered $$\hbox {D0}_{3}$$ - $$\hbox {Fe}_{3}\hbox {Al}$$ . The EDX analysis of the $$\hbox {Fe}_{75}\hbox {Al}_{25}$$ powder milled for various periods of time confirmed the gradual increase in Al diffusion in the Fe particles. The diffusion process of Al in Fe was analyzed using the elemental maps of Fe and Al in the $$\hbox {Fe}_{75}\hbox {Al}_{25}$$ powder milled for various periods of time. HRTEM images confirmed that the $$\hbox {Fe}_{3}\hbox {Al}$$ synthesized by MA is <15 nm in size.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2526-y
Issue No: Vol. 42, No. 10 (2017)

• Effect of Different Al/Ni Ratios on Structural and Acidity Properties of
Pillared Montmorillonite
• Authors: Baoru Li; Xu Wu; Zheng Li; Xia An; Xianmei Xie
Pages: 4439 - 4444
Abstract: Abstract Different Al/Ni ratios of pillared montmorillonite [Al/Ni (20, 15, 10, 6, 4, 2)-PILCs] were prepared by introducing the Al/Ni cationic polymers into montmorillonite under certain conditions. The structural properties of Al/Ni-PILCs were determined by a combination of X-ray diffraction (XRD), $$\hbox {N}_{2 }$$ adsorption–desorption, $$\hbox {NH}_{3}$$ temperature programmed desorption ( $$\hbox {NH}_{3}$$ -TPD) and scanning electron microscope (SEM). Structural characterizations showed the BET surface area and the interlayer spacing of Al/Ni-PILCs decreased regularly along with the nickel content. The weak acid sites of Al/Ni-PILCs increased compared with the Na-montmorillonite, and the strong acid sites decreased. The introduction of $$\hbox {Ni}^{2+}$$ can adjust the acidity–basicity of the Al/Ni-PILC to some extent. In the reactions of the low-concentration ethanol dehydration, Al-PILC exhibited the highest catalytic activity with 93% ethanol conversion and 99% ethylene selectivity at $$500 {^{\circ }}\hbox {C}$$ .
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2558-3
Issue No: Vol. 42, No. 10 (2017)

• Differential Electrolytic Potentiometry: a Detector in the Flow Injection
Analysis of Cyanide Using Silver Electrodes Modified with Carbon Nanotubes

• Authors: Mousa Yaser Amayreh; Abdalla Mahmud Abulkibash
Pages: 4445 - 4451
Abstract: Abstract Differential electrolytic potentiometry (DEP) using silver electrodes coated with carbon nanotubes was applied as a detector in a flow injection analysis of cyanide. The direct current differential electrolytic potentiometry (dc-DEP) and the mark-space bias differential electrolytic potentiometry (m.s.b. DEP) both were applied as indicating systems. The parameters that give the best signal were investigated and optimized. A current density of $$17 \, \upmu \hbox {A cm}^{-2}$$ and a percentage bias of 2.8% were found to be optimum in case of dc-DEP and m.s.b. DEP, respectively. The optimum flow rate of both the analyte and the supporting electrolyte was found to be of $$85 \, \upmu \hbox {L s}^{-1}$$ using a coil length of 45 cm. In case of dc-DEP, a linear range of 1–65 ppm of KCN with a detection limit of 0.5 ppm and a relative standard deviation of 2.1% was observed. In case of m.s.b. DEP, a linear range of 1–65 ppm of KCN with a detection limit of 0.35 ppm and a relative standard deviation of 1.5% was observed. The proposed DEP-FIA methods are computer controlled, fast, sensitive, inexpensive and require low consumption of reagents.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2570-7
Issue No: Vol. 42, No. 10 (2017)

• Simultaneous Determination of Enrofloxacin and Tylosin in Chicken Samples
by Derivative Spectrophotometry
• Authors: Chnar M. Rasheed; Nabil A. Fakhre; Mohamed Ibrahim
Pages: 4453 - 4463
Abstract: Abstract A novel, simple, rapid, widely applicable, and reliable derivative spectrophotometric technique for the simultaneous determination of enrofloxacin and tylosin has been developed. Enrofloxacin and tylosin belong to the category of fluoroquinolone and macrolide antibiotics, which are widely used in veterinary medicine for poultry. Residues of antibiotics in the edible tissues of food-producing animals arise due to several reasons, such as not adhering to the withdrawal period before consumption, overdosing, and use of long-lasting drugs. First-order derivative spectrophotometry was used for simultaneous determination of enrofloxacin and tylosin in the concentration range of 0.3–31.0 and 0.5–77.5  $$\upmu \hbox {g}\, \hbox {mL}^{-1}$$ , respectively. Measurements were performed at 290.69 and 347.02 nm using the zero-crossing technique and at 281.62 nm with the peak-to-baseline technique for enrofloxacin. Zero-crossing wavelengths with amplitude at 272.55, 298.33, and 322.2 nm, and the peak-to-baseline wavelength at 274 nm were used for measurements to determine tylosin. The method was applied for the determination of these antibiotics in different chicken muscle, liver, and kidney samples. The recovery percentages were in the range of 93.01–103.67%.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2745-2
Issue No: Vol. 42, No. 10 (2017)

• Removal and Extraction of Para-Nitrophenol from Aqueous Samples Using
Graphene Magnetic Nanocomposite
• Authors: Jasmin Shah; Muhammad Rasul Jan; Muhammad Zeeshan; Mehwish Iqbal
Pages: 4465 - 4472
Abstract: Abstract Graphene magnetic nanocomposite was synthesized and characterized for surface morphology, functional groups and thermal stability using scanning electron microscopy, Fourier transformed infrared spectrometry and thermogravimetric analysis. The composite was investigated for the extraction and removal of p-nitrophenol from aqueous samples. Different experimental factors such as pH, composite dose, time, temperature and concentration of p-nitrophenol were studied for the removal. At pH 4, p-nitrophenol removal efficiency was high and then decreased with increase in pH up to 10. The removal of p-nitrophenol was high with 60 min time and the % sorption remained constant up to 90 min. Experimental data of kinetic models were explained best by the pseudo-second-order kinetic model with sorption capacity and correlation coefficient values of 45.87 mg/g and 0.9998, respectively. The isotherm data followed Langmuir isotherm with correlation coefficient of 0.9903 and sorption capacity $$(\hbox {Q}_{{{\circ }}})$$ of 500 mg/g. The sorption of p-nitrophenol was found exothermic in nature and physisorption process involved in the sorption of p-nitrophenol on graphene magnetic nanocomposite. Electron donor–acceptor and hydrogen-bonding interactions were the mechanism involved in sorption. The results revealed that graphene magnetic nanocomposite has faster rate of removal of p-nitrophenol and can be used as a sorbent.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2713-x
Issue No: Vol. 42, No. 10 (2017)

• Enhancement of Fire Retardancy Using Surface-Modified Silica Spheres with
Aluminum Hydroxide
• Authors: Ha-Sung Kong; Byoung-Ju Kim; Kwang-Sun Kang
Pages: 4473 - 4477
Abstract: Abstract Large surface area and fire-inert property of sub-micrometer silica spheres were employed to improve the fire retardant performance by attaching large number of Si–O–Al(OH) $$_{2}$$ groups. Various amounts of AlCl $$_{3}$$ were attached to the surface of silica spheres and the residual –AlCl $$_{2}$$ was hydrolyzed by adding excess amount of KOH. Although the FESEM image of pure silica spheres showed smooth surface, the surface-modified silica spheres exhibited nanoparticles on the surface of silica spheres. The characteristic absorption peaks of Al–OH and Si–O–Al were detected by FTIR spectra. Silica spheres attached with Si–O–Al(OH) $$_{2}$$ were uniformly distributed on the surface of cellulose acetate films. The performance of the fire retardant was greatly enhanced by increasing the amount of aluminum hydroxide.
PubDate: 2017-10-01
DOI: 10.1007/s13369-017-2721-x
Issue No: Vol. 42, No. 10 (2017)

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs