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  Subjects -> ENGINEERING (Total: 2003 journals)
    - CHEMICAL ENGINEERING (158 journals)
    - CIVIL ENGINEERING (153 journals)
    - ELECTRICAL ENGINEERING (86 journals)
    - ENGINEERING (1128 journals)
    - ENGINEERING MECHANICS AND MATERIALS (303 journals)
    - HYDRAULIC ENGINEERING (47 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (76 journals)

ENGINEERING (1128 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Lifecycle Performance Engineering     Hybrid Journal  
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 4)
International Journal of Manufacturing Research     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 7)
International Journal of Materials and Product Technology     Hybrid Journal   (Followers: 4)
International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 7)
International Journal of Mathematics in Operational Research     Hybrid Journal   (Followers: 1)
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 5)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 4)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Microwave Science and Technology     Open Access   (Followers: 2)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 3)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 2)
International Journal of Nanomanufacturing     Hybrid Journal   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 2)
International Journal of Navigation and Observation     Open Access   (Followers: 6)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Full-text available via subscription  
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 7)
International Journal of Optics     Open Access   (Followers: 1)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 9)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 2)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 3)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal  
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 4)
International Journal of Polymer Science     Open Access   (Followers: 16)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 2)
International Journal of Production Economics     Hybrid Journal   (Followers: 12)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 4)
International Journal of Quality Assurance in Engineering and Technology Education     Full-text available via subscription   (Followers: 2)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 1)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 6)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 8)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 2)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 1)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal  
International Journal of Social Robotics     Hybrid Journal   (Followers: 1)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 1)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 3)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 6)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Systems and Service-Oriented Engineering     Full-text available via subscription  
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal of Technoethics     Full-text available via subscription  
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 4)
International Journal of Telemedicine and Applications     Open Access   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 5)
International Journal of Thermodynamics     Open Access   (Followers: 2)
International Journal of Turbo & Jet-Engines     Full-text available via subscription  
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal   (Followers: 1)
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 5)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 4)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal  
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 4)
International Nano Letters     Open Access   (Followers: 8)
International Review of Applied Sciences and Engineering     Full-text available via subscription  
Inverse Problems in Science and Engineering     Hybrid Journal   (Followers: 2)
Ionics     Hybrid Journal  
IPTEK The Journal for Technology and Science     Open Access  
IRBM News     Full-text available via subscription  
Irrigation and Drainage Systems     Hybrid Journal  
ISA Transactions     Full-text available via subscription   (Followers: 1)
ISRN - International Scholarly Research Notices     Open Access   (Followers: 69)
ISRN Nanotechnology     Open Access  
ISRN Signal Processing     Open Access  
ISRN Thermodynamics     Open Access  
IT Professional     Full-text available via subscription   (Followers: 3)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 1)
Journal of Advanced Manufacturing Systems     Hybrid Journal   (Followers: 6)
Journal of Aerosol Science     Hybrid Journal   (Followers: 1)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 151)
Journal of Alloys and Compounds     Hybrid Journal   (Followers: 8)
Journal of Analytical and Applied Pyrolysis     Hybrid Journal   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 4)
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 1)
Journal of Applied Analysis     Full-text available via subscription  
Journal of Applied and Industrial Sciences     Open Access  
Journal of Applied Logic     Full-text available via subscription  

  First | 2 3 4 5 6 7 8 9 | Last

Journal Cover Ionics
   Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1862-0760 - ISSN (Online) 0947-7047
     Published by Springer-Verlag Homepage  [2210 journals]   [SJR: 0.522]   [H-I: 25]
  • Structural and electrochemical properties of LiFe
           1 − 3x/2 Bi x PO 4 /C synthesized by sol–gel
    • Abstract: Abstract In this study, LiFe1 − 3x/2Bi x PO4/C cathode material was synthesized by sol–gel method. From XRD patterns, it was found that the Bi-doped LiFePO4/C cathode material had the same olivine structure with LiFePO4/C. SEM studies revealed that Bi doping can effectively decrease the particle sizes. It shortened Li+ diffusion distance between LiFePO4 phase and FePO4 phase. The LiFe0.94Bi0.04PO4/C powder exhibited a specific initial discharge capacity of about 149.6 mAh g−1 at 0.1 rate as compared to 123.5 mAh g−1 of LiFePO4/C. EIS results indicated that the charge-transfer resistance of LiFePO4/C decreased greatly after Bi doping.
      PubDate: 2014-12-01
       
  • Ball-milled Ni-Mn-Zn hydroxide for alkaline secondary battery
    • Abstract: Abstract In our previous study, Mn-substituted nickel hydroxide (Ni0.8Mn0.2(OH)2) was prepared by a simple ball milling method to reduce the cost of nickel hydroxide for alkaline secondary battery, but compared to the Ni(OH)2 electrode, the Ni0.8Mn0.2(OH)2 one showed an obvious decrease in its discharge potential. In this paper, Zn and Mn co-substituted nickel hydroxide (Ni0.8Mn0.2 − x Zn x (OH)2, x = 0–0.075) is prepared by ball milling. The results of the cyclic voltammetry (CV) tests illustrate that the co-reduction of Mn(IV) to Mn(III) and NiOOH is observed on the Ni0.8Mn0.2 − x Zn x (OH)2 electrodes, and it has a lower reduction potential than NiOOH. The co-substitution of Zn can effectively increase the co-reduction potential. The ball-milled Ni0.8Mn0.15Zn0.05(OH)2 electrode has a similar capacity (about 270 mAh g−1 at a 0.2C rate) and cycling durability to the commercial Ni(OH)2 with ball milling treatment, but the former has better high-power performance.
      PubDate: 2014-12-01
       
  • Electrochemical determination of ionization constants of
           
    • Abstract: Abstract Cyclic voltammetry of ferrocene at glassy carbon electrode in acetonitrile (ACN), ο-nitrophenyloctylether (NPOE) and ACN-NPOE mixture with 0.2 M tetrabutylammonium tetrafluoroborate (TBABF4) were investigated. Both cathodic and anodic peak current were diffusion-controlled at any NPOE fraction. However, the peak current was decreased with the increasing NPOE fraction. In addition, the peak potential difference increased not only with an increase in the NPOE fraction but also in the scan rate, while the values of half-wave potential did not vary largely with the fraction or the scan rate. This indicated that the variation of peak current and peak potential should be due to the variation of the solution resistance. In order to demonstrate this assumption, the conductance of TBABF4 in ACN, NPOE, and ACN-NPOE mixture were determined by AC impedance. All of the solution conductances were inversely linear to the viscosity of the solvent, which was increased with the fraction of NPOE. The calculated ionization constant of TBABF4 in ACN was 2.8 times of that in NPOE. TBABF4 in ACN can work as a supporting electrolyte, whereas they work partly in NPOE.
      PubDate: 2014-12-01
       
  • The influence of sodium gluconate on nickel and manganese codeposition
           from acidic chloride-sulfate baths
    • Abstract: Abstract Nickel and manganese were codeposited from acidic chloride-sulfate solution in the presence and without sodium gluconate as complexing and buffering agent. Equilibrium pH-dependent distribution of soluble species in the baths was calculated. Deposition of metals was studied by cyclic voltammetry and Hull cell tests. Deposits were obtained in potentiostatic (−1.6 to −1.7 V vs. Ag/AgCl) and galvanostatic (4–8 A/dm2) conditions. It was found that the buffering action of gluconate ions improved the quality of the deposits, and compact Ni-Mn with a grid of fine crack layers was produced. The additive inhibited the formation of nonmetallic inclusions represented by decreased oxygen content in the deposits. Layers produced at constant potentials contained 67–79 % Ni, 1–8 % Mn, and 15–30 % O. Under galvanostatic conditions, the average compositions were in the range of 18–80 % Ni, 2–48 % Mn, and 17–42 % O. Despite of the bath composition, the main cathodic reaction was hydrogen evolution resulting in very low amounts of the cathodic deposits.
      PubDate: 2014-12-01
       
  • Effect of molybdenum doping on the electrochromic properties of tungsten
           oxide thin films by RF magnetron sputtering
    • Abstract: Abstract Thin films of pure and molybdenum (Mo)-doped tungsten trioxide (WO3) were deposited on indium tin oxide (ITO)-coated glass and Corning glass substrates by RF magnetron sputtering technique. The effect of Mo doping on the structural, morphological, optical and electrochromic properties of WO3 films was studied systematically. The energy dispersive X-ray analysis (EDAX) revealed that the films consist of molybdenum concentrations from 0 to 2 at.%. X-ray diffraction (XRD) studies indicated that with the increase of Mo concentration the structural phase transformation takes place from polycrystalline to amorphous phase. The crystallite size of the films decreased from 24 to 12 nm with increase of doping concentration of Mo in WO3. Scanning electron microscope (SEM) analysis revealed that Mo dopant led to significant changes in the surface morphology of the films. The electrochemical and electrochromic performance of the pure and Mo-doped WO3 were studied. The WO3 films formed with 1.3 at.% Mo dopant concentration exhibited high optical modulation of 44.3 % and coloration efficiency of 42.5 cm2/C.
      PubDate: 2014-12-01
       
  • Perborate as novel fuel for enhanced performance of membraneless fuel
           cells
    • Abstract: Abstract This paper presents the development of membraneless sodium perborate fuel cell using acid/alkaline electrolyte. In the acid/alkaline electrolyte, perborate works both as an oxidant as well as reductant. Sodium perborate affords hydrogen peroxide in aqueous medium. The cell converts the energy released by H2O2 decomposition with H+ and OH− ions into electricity and produces water and oxygen. Such a novel design eliminates the need of a membrane, in which acid and alkaline electrolytes contact with each other. At room temperature, the laminar flow-based microfluidic membraneless fuel cell can reach a maximum power density of 34 mW/cm2 with the molar ratio of [Perborate]/[NaOH] = 1 as fuel and [Perborate]/[H2SO4] = 2 as oxidant. The paper reports for the first time the use of sodium perborate as the oxidant and reductant. The developed fuel cell emits no CO2, features no proton exchange membrane, inexpensive catalysts, and simple planar structure, which enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.
      PubDate: 2014-12-01
       
  • Synthesis and characteristics of KTa 0.5 Nb 0.5 O 3 thin films
    • Abstract: Abstract KTa0.5Nb0.5O3 thin films were synthesized via a metal-organic solution. Characteristics were measured, such as X-ray diffraction pattern, surface morphology and roughness, and electric properties. The synthesized films have a (100) preferential growth orientation on Si (100) substrate. The homogeneous microstructure and smooth surface benefit to the good electric properties of the thin films. The current density-voltage characteristic shows an unexpected feature of the transition from linear to nonlinear, which can be explained by the space-charge-limited mode. Dielectric constant and loss of the thin films decrease with the increase of frequency. The decrease of dielectric loss is related to the decrease of net polarization in material. The decrease of dielectric constant can be explained by Debye formula. The phase transition temperature T c is about 102 °C for KTa0.5Nb0.5O3 materials.
      PubDate: 2014-12-01
       
  • Conduction mechanism of lithium bis(oxalato)borate–cellulose acetate
           polymer gel electrolytes
    • Abstract: Abstract Polymer gel electrolytes (PGE) belonging to salt–solvent–polymer hybrid systems are prepared using a mixture of lithium bis(oxalato)borate (LiBOB), γ-butyrolactone (γ-BL), and cellulose acetate (CA). The increase in ionic conductivity of PGE is due to the dissociation of ion aggregates, as confirmed by Fourier transform infrared analysis. The highest conductivity attained by the PGE is 7.05 mS cm−1 at 2.4 wt.% CA. The plots of conductivity–temperature show a classical Arrhenius relationship. The electrical properties of the sample with the highest conductivity are analyzed using electrical permittivity and electric modulus formalism studies. Meanwhile, the frequency-dependent conductivity of the polymer gel electrolyte adheres to Jonscher’s power law. Conduction mechanism study also shows that the 2.4 wt.% CA PGE is in agreement with the small polaron hopping model.
      PubDate: 2014-12-01
       
  • Binary composite ionic liquids [bmim][BF 4 ] and [bmim][Ac] for
           electrochemical reduction of nitrobenzene
    • Abstract: Abstract The binary composite ionic liquid mixtures composed of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) and 1-butyl-3-methylimidazolium acetate ([bmim][Ac]) were studied and used in electroreduction of nitrobenzene for the first time. 1H NMR and Fourier transform infrared (FTIR) spectroscopy were carried out to acquire a deep understanding of the interaction of binary ionic liquids, and UV/Vis spectroscopy was used to study the interaction between the mixture of ionic liquids and nitrobenzene. It was found that chemical shifts of all protons were changed and significant changes in the anion IR bands were induced, and the UV maximum absorption wavelength and absorbance of nitrobenzene in binary ionic liquids were different from those in the neat ionic liquid. The electrochemical reduction behavior of nitrobenzene in binary composite ionic liquids on platinum electrode was studied by cyclic voltammetry, in situ Fourier transform infrared spectroscopy, and constant potential electrolysis. Results indicated that the reduction of nitrobenzene in binary composite ionic liquids demonstrated higher current densities with a more positive potential, and the product (azobenzene) showed higher yield and selectivity in the composite ionic liquids than in the neat ionic liquids; the concentrations of water in the binary mixtures of ionic liquids had great effect on the electrochemical behavior of nitrobenzene. In the end, the mechanism of reduction of nitrobenzene in binary mixtures of ionic liquids was discussed.
      PubDate: 2014-12-01
       
  • Electrochemical and structural study of neodymium nickelate thick film
           deposited by spin coating on an oxyapatite electrolyte
    • Abstract: Abstract The electrochemical characteristics of an Nd2NiO4 cathode, synthesized using the citric acid-nitrate combustion method and symmetrically deposited by spin coating on both surfaces of an La9.33Si5.3Al0.7O25.65 (LSAO) electrolyte, were studied using AC impedance spectroscopy. It was found that, varying the temperature (600 to 850 °C) and the oxygen partial pressure (0.2–10−7 atm), the impedance characteristics of the electrode could be determined by three different processes. Said processes were ionic conduction in the electrode bulk, interfacial charge transfer, and gas-phase diffusion, all of which are based on the temperature and oxygen partial pressure dependence on the polarization resistance, which is associated with each individual processes as well as on the corresponding capacitance values.
      PubDate: 2014-12-01
       
  • Preparation and characterization of polyaniline+TiO 2 composite films
    • Abstract: Abstract In this work, we have prepared electrochemically and studied a composite materials based on an organic conducting polymer, polyaniline (PANI), in which inorganic semiconductor titanium dioxide (TiO2) particles were incorporated with different concentrations. The polyaniline/titanium dioxide composite material which had been deposited by cyclic voltammetry on substrates of indium tin oxide was then characterized. The cyclic voltammogram showed one redox couple characteristic of the oxidation and reduction states of the produced composite material. The impedance spectroscopy study showed that the resistance of the film increases with the TiO2 cocntent incorporated in the polymer. The incorporation of TiO2 in PANI covering the surfaces was confirmed by the scanning electron microscopy and the energy dispersive X-ray analysis. The morphological analysis of the film surfaces showed that the TiO2 nanoparticle increased the roughness. These observations allow to consider a new approach to improve the physicochemical properties of the interface between the organic and inorganic material. The I–V characteristics of PANI+TiO2 heterostructure diode showed the nonlinear nature of the I–V curve of PANI+TiO2 heterostructure device.
      PubDate: 2014-12-01
       
  • Increasing the crystallite and conductivity of polypyrrole with dopant
           used
    • Abstract: Abstract The chemical polymerization method is very convenient for obtaining a plurality of the polymer. Chemical synthesizes of polypyrrole (PPy) were performed in acetonitrile solutions containing different dopants: dodecylbenzene sulphonic acid (DBSA), tetrafluoroborate (BF4 −), perchlorate (ClO4 −) and oxalate (C2O4 2−). These polymers were characterized by using scanning electron microscopy (SEM), ultraviolet–visible (UV–Vis) spectrophotometer, Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD) techniques and dry conducting measurement. It was observed that the interactions between the polymers and dopant materials are completely different from each other. As a result of this interaction, the conductivities and crystal structures of PPy are also different from each other. Results in this work showed that the dopants used affected both electrical conductivities and crystal structures of PPy.
      PubDate: 2014-12-01
       
  • Spectroscopic studies on ion dynamics of PVP–NH 4 SCN polymer
           electrolytes
    • Abstract: Abstract Proton-conducting polymer electrolyte comprising of poly(N-vinyl pyrrolidone) (PVP) and ammonium thiocyanate (NH4SCN) are prepared by solvent casting method with different polymer–salt concentrations. The changes in the Raman spectra with increasing NH4SCN concentration state that the free ion concentration is maximum for 20 mol% NH4SCN concentrated system. At higher salt concentrations (25 mol%), the effective number of charge carriers decreases due to the formation of ion aggregates as confirmed by the Raman analysis. Solid-state NMR and MAS NMR studies are performed to obtain the information about the ionic structure, mobility of the charge carriers, and also to gain insight into the polymer–salt interactions in the polymer electrolytes. The results of ionic transference number show that the charge transport in these polymer electrolytes is mainly due to ions.
      PubDate: 2014-12-01
       
  • Electrochemical and catalytic investigations of epinephrine, acetaminophen
           and folic acid at the surface of titanium dioxide nanoparticle-modified
           carbon paste electrode
    • Abstract: Abstract In the present paper, the use of a carbon paste electrode modified with 1-(4-(1, 3-dithiolan-2-yl)-6, 7-dihydroxy-2-methyl-6, 7-dihydrobenzofuran-3-yl)ethanone (DDE) and TiO2 nanoparticles prepared by a simple and rapid method was described. The modified electrode showed excellent properties for electrocatalytic oxidization of epinephrine (EP), acetaminophen (AC) and folic acid (FA). The apparent charge transfer rate constant, k s = 1.14 s−1, and transfer coefficient, α = 0.54, for electron transfer between the modifier and carbon paste electrode were calculated. It has been found that under optimum condition (pH = 7.0) in cyclic voltammetry, the oxidation of EP occurs at a potential about 280 mV less positive than that of an unmodified carbon paste electrode. The values of transfer coefficients (α = 0.46), catalytic rate constant (k = 1.2 × 104 M−1 s−1) and diffusion coefficient (D = 2.70 × 10−5 cm2 s−1) were calculated for EP. Differential pulse voltammetry (DPV) exhibited two linear dynamic ranges of 0.5 to 50.0 μM and 50.0 to 1,000 μM for EP. This modified electrode is quite effective not only for the detection of EP, AC and FA but also for the simultaneous determination of these species in a mixture. The limit of detection for EP, AC and FA is 0.10, 1.80 and 2.36 μM, respectively.
      PubDate: 2014-12-01
       
  • Enhancement in electrochemical properties of ionic liquid-based
           nanocomposite polymer electrolytes by 100 MeV Si 9+ swift heavy ion
           irradiation
    • Abstract: Abstract Swift heavy ion (SHI) irradiation has been used as a tool to enhance the electrochemical properties of ionic liquid-based nanocomposite polymer electrolytes dispersed with dedoped polyaniline (PAni) nanorods; 100 MeV Si9+ ions with four different fluences of 5 × 1010, 1 × 1011, 5 × 1011, and 1 × 1012 ions cm−2 have been used as SHI. XRD results depict that with increasing ion fluence, crystallinity decreases due to chain scission up to fluence of 5 × 1011 ions cm−2, and at higher fluence, crystallinity increases due to cross-linking of polymer chains. Ionic conductivity, electrochemical stability, and dielectric properties are enhanced with increasing ion fluence attaining maximum value at the fluence of 5 × 1011 ions cm−2 and subsequently decrease. Optimum ionic conductivity of 1.5 × 10−2 S cm−1 and electrochemical stability up to 6.3 V have been obtained at the fluence of 5 × 1011 ions cm−2. Ac conductivity studies show that ion conduction takes place through hopping of ions from one coordination site to the other. On SHI irradiation, amorphicity of the polymer matrix increases resulting in increased segmental motion which facilitates ion hopping leading to an increase in ionic conductivity. Thermogravimetric analysis (TGA) measurements show that SHI-irradiated nanocomposite polymer electrolytes are thermally stable up to 240–260 °C.
      PubDate: 2014-12-01
       
  • A review of research on hematite as anode material for lithium-ion
           batteries
    • Abstract: Abstract Hematite (α-Fe2O3) nanomaterials have been investigated intensively as a promising anode material for Li-ion batteries due to their advantages such as high theoretical capacity, low cost, environmental friendliness, high resistance to corrosion, etc. However, their practical application is hampered by poor capacity retention, low Coulombic efficiency, and poor high-rate capacity. To overcome these drawbacks, many effective works have been proposed. This review focuses first on the present status of α-Fe2O3 nanomaterials in the field of Li-ion batteries including their features, synthesized methods, modification, application and then on their near future development.
      PubDate: 2014-12-01
       
  • Vanadium(V) catalysis of perborate oxidation of substituted 5-oxo acids: a
           kinetic and mechanistic study
    • Abstract: Abstract Vanadium (V) catalyzes perborate oxidation of substituted 5-oxo acid in acidic solution, being 1.6 order with respect to the oxidant, first order in the catalyst, inhibited by H+ and displays Michaelis–Menten kinetics on the reductant. In aqueous acetic acid solution, perborate generates hydrogen peroxide and the kinetic results reveal formation of oxodiperoxovanadium(V)-oxo acid complex. At high acidity, the ionic strength of the medium has little influence on the oxidation rates. But at low acidity, the rate increases with increasing ionic strength. The rate of oxidation increases with decreasing dielectric constant of the medium. Electron-releasing substituents in the aromatic ring accelerate the reaction rate and electron-withdrawing substituents retard the reaction. The order of reactivity among the studied 5-oxo acid is p-methoxy >> p-methyl > p-phenyl > -H > p-chloro > p-bromo > m-nitro. Activation parameters have been evaluated using Arrhenius and Eyring’s plots. A mechanism consistent with the observed kinetic data has been proposed and discussed. A suitable rate law has been derived based on the mechanism.
      PubDate: 2014-12-01
       
  • Effect of synthetic methods on electrochemical performances of VOPO 4
           ·2H 2 O supercapacitor
    • Abstract: Abstract In this paper, we studied the VOPO4·2H2O as an electrode material for supercapacitors. A systematic comparison of VOPO4·2H2O prepared by reflux and hydrothermal methods was carried out through detailed analyses that included power X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Their electrochemical performances were also investigated by using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). Meanwhile, we proposed a possible charge storage mechanism on the VOPO4·2H2O electrode surface. The material synthesized by reflux method had better performance in the capacitance than that by hydrothermal method, and its specific capacitance was up to 202 F/g at 2 mV/s. A total of 67.4 % of capacitance was maintained for the VOPO4·2H2O synthesized by reflux method when current density changed from 0.2 to 2 A/g, much higher than those obtained from the hydrothermal-synthesized VOPO4·2H2O supercapacitor of 42.5 %. The energy density of VOPO4·2H2O supercapacitor synthesized by reflux method was 18.7 Wh/kg at 290 W/kg and maintained 6.2 Wh/kg at 1,421 W/kg, much higher than the hydrothermal-synthesized VOPO4·2H2O supercapacitor. Our work confirms that VOPO4·2H2O is a potential electrode material for supercapacitors.
      PubDate: 2014-11-25
       
  • Floss-like Ni–Co binary hydroxides assembled by whisker-like
           nanowires for high-performance supercapacitor
    • Abstract: Abstract Floss-like Ni–Co binary hydroxides (FL-NCOH), assembled by whisker-like nanowires, are synthesized via a facile hydrothermal process with sodium dodecyl benzene sulfonate (SDBS) as the soft template. The forming process of FL-NCOH is clarified by tuning the hydrothermal reaction time. The result indicates that floccule-like nickel–cobalt hydroxide nanoclusters gradually become longer and slenderer nanowires to form FL-NCOH with the increase of reaction time. The dissolution–recrystallization of hydroxide plays an important role in the morphology control of nickel–cobalt hydroxide. The high specific surface area (106.5 m2 g−1) and the suitable 3D structure endow the as-prepared FL-NCOH material high specific capacitance (up to 918.9 F g−1 at the current density of 0.2 A g−1), good high-rate performance (594.2 F g−1 even at 10.0 A g−1), and long cycle life (98.7 % capacitance retention after 3000 charge–discharge cycles at 2.0 A g−1). Graphical Abstract ᅟ
      PubDate: 2014-11-25
       
  • Nanostructured photoelectrochemical solar cells with polyaniline nanobelts
           acting as hole conductors
    • Abstract: Abstract Nanostructured photoelectrochemical solar cells have been prepared by combining a Sb2S3-sensitized photoactive electrode, polyaniline nanobelts, and a Ag counter electrode to form a layered structure. Here, Sb2S3 acts as an absorbing semiconductor, and polyaniline acts as both a hole conductor and light absorber (a hole-conducting dye). Via the optimization that eventually determines the chemical bath deposition duration to be 3 h, the cell shows a high photovoltaic performance with 7.05 mA/cm2-short-circuit current density, 0.695 V-open-circuit voltage, 0.457 fill factor, and 2.24 % power conversion efficiency. The prepared devices are stable under room light in ambient conditions (even without encapsulation).
      PubDate: 2014-11-25
       
 
 
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