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  Subjects -> ENGINEERING (Total: 2096 journals)
    - CHEMICAL ENGINEERING (176 journals)
    - CIVIL ENGINEERING (161 journals)
    - ELECTRICAL ENGINEERING (88 journals)
    - ENGINEERING (1157 journals)
    - ENGINEERING MECHANICS AND MATERIALS (330 journals)
    - HYDRAULIC ENGINEERING (53 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (79 journals)

ENGINEERING (1157 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Imaging Systems and Technology     Hybrid Journal   (Followers: 2)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 7)
International Journal of Information Acquisition     Hybrid Journal   (Followers: 1)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 2)
International Journal of Innovation Science     Full-text available via subscription   (Followers: 6)
International Journal of Innovative Technology and Research     Open Access  
International Journal of Integrated Engineering     Open Access   (Followers: 1)
International Journal of Intelligent Engineering Informatics     Hybrid Journal  
International Journal of Intelligent Systems and Applications in Engineering     Open Access  
International Journal of Lifecycle Performance Engineering     Hybrid Journal   (Followers: 1)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 5)
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: 3)
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: 5)
International Journal of Polymer Science     Open Access   (Followers: 16)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 5)
International Journal of Precision Engineering and Manufacturing-Green Technology     Hybrid Journal  
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 3)
International Journal of Production Economics     Hybrid Journal   (Followers: 13)
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: 7)
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: 2)
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: 4)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 6)
International Journal of Superconductivity     Open Access  
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: 7)
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: 9)
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  
Ironmaking & Steelmaking     Hybrid Journal   (Followers: 2)
Irrigation and Drainage Systems     Hybrid Journal  
ISA Transactions     Full-text available via subscription   (Followers: 1)
ISRN - International Scholarly Research Notices     Open Access   (Followers: 68)
ISRN Nanotechnology     Open Access  
ISRN Signal Processing     Open Access   (Followers: 1)
ISRN Thermodynamics     Open Access  

  First | 2 3 4 5 6 7 8 9 | Last

Journal Cover   Ionics
  [SJR: 0.497]   [H-I: 27]   Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1862-0760 - ISSN (Online) 0947-7047
   Published by Springer-Verlag Homepage  [2302 journals]
  • Electrochemical studies on novel films consisting of phosphorus-doped
           multi-walled carbon nanotubes
    • Abstract: Abstract Films consisting of phosphorus-doped multi-walled carbon nanotubes (further denoted as P-MWCNTs) were fabricated by means of chemical vapor deposition technique with decomposition of triphenylphosphine in the presence of catalyst. The P-MWCNTs films were characterized using scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. The P-MWCNTs films were electrochemically investigated with respect to their response to ferrocyanide/ferricyanide, [Fe(CN)6]3−/4− by means of cyclic voltammetry and electrochemical impedance spectroscopy techniques. The findings reveal that the phosphorus-doping of nanotubes improves their electrochemical response, but it cannot compete the nitrogen-doping of nanotubes, that enhances even more the sensitivity and detection ability of carbon nanotubes. Specifically, the limit of detection of P-MWCNTs towards [Fe(CN)6]3−/4− (LOD = 1.0 μM) lies between those obtained for pristine MWCNTs (LOD = 1.57 μM) and nitrogen-doped MWCNTs (LOD = 0.47 μM). The findings exhibit the important role which plays the doping of carbon nanotubes with elements for the improvement of their electrocatalytic properties.
      PubDate: 2015-04-01
       
  • Synthesis and electrochemical properties of P2-Na 2/3 Ni 1/3 Mn 2/3 O 2
    • Abstract: Abstract The pure phase P2-Na2/3Ni1/3Mn2/3O2 was synthesized by a solid reaction process. The optimum calcination temperature was 850 °C. The as-prepared product delivered a capacity of 158 mAh g−1 in the voltage range of 2–4.5 V, and there was a phase transition from P2 to O2 at about 4.2 V in the charge process. The P2 phase exhibited excellent intercalation behavior of Na ions. The reversible capacity is about 88.5 mAh g−1 at 0.1 C in the voltage range of 2–4 V at room temperature. At an elevated temperature of 55 °C, it could remain as an excellent capacity retention at low current rates. The P2-Na2/3Ni1/3Mn2/3O2 is a potential cathode material for sodium-ion batteries.
      PubDate: 2015-04-01
       
  • Dinitrile compound containing ethylene oxide moiety with enhanced
           solubility of lithium salts as electrolyte solvent for high-voltage
           lithium-ion batteries
    • Abstract: Abstract A dinitrile compound containing ethylene oxide moiety (4,7-dioxa-1,10-decanedinitrile, NEON) is synthesized as an electrolyte solvent for high-voltage lithium-ion batteries. The introduction of ethylene oxide moiety into the conventional aprotic aliphatic dinitrile compounds improves the solubility of lithium hexafluorophosphate (LiPF6) used commercially in the lithium-ion battery industry. The electrochemical performances of the NEON-based electrolyte (0.8 M LiPF6 + 0.2 M lithium oxalyldifluoroborate in NEON:EC:DEC, v:v:v = 1:1:1) are evaluated in graphite/Li, LiCoO2/Li, and LiCoO2/graphite cells. Half-cell tests show that the electrolyte exhibits significantly improved compatibility with graphite by the addition of vinylene carbonate and lithium oxalyldifluoroborate and excellent cycling stability with a capacity retention of 97 % after 50 cycles at a cutoff voltage of 4.4 V in LiCoO2/Li cell. A comparative experiment in LiCoO2/graphite full cells shows that the electrolyte (NEON:EC:DEC, v:v:v = 1:1:1) exhibits improved cycling stability at 4.4 V compared with the electrolyte without NEON (EC:DEC, v:v = 1:1), demonstrating that NEON has a great potential as an electrolyte solvent for the high-voltage application in lithium-ion batteries.
      PubDate: 2015-04-01
       
  • A new hyperbranched star polyether electrolyte with high ionic
           conductivity
    • Abstract: Abstract Hyperbranched poly(glycidol) containing hydroxyl groups was firstly synthesized via anionic polymerization and then reacted with 2-bromoisobutyl bromide to form macroinitiator HPG-Br. Finally, a hyperbranched star polymer (HPG-PPEGMA) was successfully prepared by atom transfer radical polymerization (ATRP) of poly(ethylene glycol) methyl ether methacrylate using HPG-Br as macroinitiator. The structures and properties of the obtained polymers were characterized by 1H NMR, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The ionic conductivity of the polymer electrolytes composed of HPG-PPEGMA and lithium bis(trifluoromethanesulfonimide) (LiTFSI) was investigated via electrochemical impedance spectroscopy. The results showed that the room temperature ionic conductivity of the prepared hyperbranched star polymer electrolytes had a higher ionic conductivity. When [EO]/[Li] was 20, the ionic conductivity of the hyperbranched star polymer electrolyte was up to 1 × 10−4 Scm−1 at 30 °C. The onset decomposition temperature of the hyperbranched star polyether could reach 374 °C, indicating that the hyperbranched star polymer had a good thermal stability. The XRD results showed that the structure of the hyperbranched star polymer was beneficial to improve the ionic conductivity due to possessing a low degree of crystallinity.
      PubDate: 2015-04-01
       
  • The role of crystallization on microstructural and electrical studies of
           lithium germanium phosphate glass-ceramic electrolytes
    • Abstract: Abstract The glass-ceramic samples with the general formula: (100 − x) [0.4Li2O-0.1GeO2-0.6P2O5] + x 40-h ball-milled Al2O3 (where x = 0, 2, 4, 6, 8, 10, and 12 mol%) were synthesized by high-energy ball milling technique. X-ray diffraction (XRD) analysis revealed that the phases such as LiGe2(PO4)3, Li4P2O7, GeO2, and AlPO4 were identified from major diffraction peaks of LGPA samples. The intensity and broadening of XRD peaks of LGPA glass-ceramic samples displayed that the LGPA10 glass-ceramic possesses major crystalline phases namely sodium super ionic conductor (NASICON)-type phases of LiGe2(PO4)3 and Li4P2O7. Scanning electron micrograph (SEM) pictures further confirmed that the sample LGPA10 has the presence of particles of varied sizes (20–30 nm) and also large clusters of less than 60 nm dispersed uniformly in a continuous glass matrix. The slight difference in the Z″ and M″ peaks for the LGPA samples suggests the presence of possibly more than one mechanism.
      PubDate: 2015-04-01
       
  • Silver-doped silver vanadate glass composite electrolyte: structure and an
           investigation of electrical properties
    • Abstract: Abstract Structural and electrical properties of the ternary ionic–electronic conducting glass system xAgI–(1 − x)[0.67Ag2O–0.33V2O5], where x = 0.4, 0.5, 0.6, 0.7, and 0.8 were studied for emphasizing the influence of silver iodide concentration on the transport properties of the based vanadate glasses. The glasses were prepared by melt quenching technique and characterized using X-ray diffraction (XRD), FTIR spectra, and differential thermal analysis (DTA). Electrical conductivity (σ), dielectric constant (ε′), dielectric loss (ε″), and impedance spectra (Z′-Z″) were studied for all samples. All glasses showed a mixed ionic–electronic conductance with a high ionic conductivity for the sample with x = 0.7. The electronic contribution to the total conductivity and the ionic (t i) and electronic transport numbers (t e) were determined for each glass sample using Wagner’s DC polarization technique. The variation in electrical properties with each of composition, temperature, and frequency was analyzed and discussed. Graphical Abstract AgI dopant (0.7 mol) created more opened vanadate network structure and enhanced both ion migration and orientation and as a result showed a high DC conductivity and ionic transfer number at room temperature.
      PubDate: 2015-04-01
       
  • Preparation, characterization, and ion exchange behavior of nanocomposite
           polyaniline zirconium(IV) selenotungstophosphate for the separation of
           toxic metal ions
    • Abstract: Abstract A conducting polymer-based advanced nanocomposite ion exchanger was synthesized by incorporating polyaniline (PANI) into the inorganic counterpart zirconium(IV) selenotungstophosphate (ZSWP). The nanocomposite exhibited an excellent ion exchange capacity of 1.20 meq g−1 in addition to high thermal stability. The polymeric–inorganic nanocomposite ion exchanger was characterized by Fourier transform infrared (FTIR), XRD, SEM, and TEM studies. The DC conductivity of PANI/ZSWP was also investigated. The nanocomposite ion exchanger was found to be highly selective for Cu2+ ions with a distribution coefficient value of 650 mL/g. The analytical applications of the material were explored by achieving selective separations of Cu2+ and Ca2+ ions from a synthetic mixture of Cu2+, Pb2+, Zn2+, Ni2+, Fe3+, Mg2+, and Al3+ and Ca2+, Pb2+, Zn2+, Ni2+, Al3+, Mg2+, and Ba2+.
      PubDate: 2015-04-01
       
  • Field enhanced Li ion conduction in nanoferroelectric modified polymer
           electrolyte systems
    • Abstract: Abstract Nanocomposite polymer electrolyte (NCPE) films based on polyethylene oxide (PEO) complexed with lithium perchlorate (LiClO4) and nanosized ferroelectric ceramic fillers such as BaTiO3, SrTiO3 have been prepared using solution cast technique. The films showed very good mechanical stability when exposed to ambient atmospheres for prolonged periods. Lithium ion transport studies revealed that the conductivity is predominantly ionic. The effect of electric field on ionic conductivity of NCPE films was investigated. One order enhancement in conductivity due to the field was observed at 323 K. NCPE films exhibited conductivity of 3.46 × 10−5 Scm−1 at 323 K. NCPE films were characterized using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) technique. The DSC and XRD studies revealed reduced crystallinity which confirmed the higher amorphous phase and hence the improved ionic conductivity.
      PubDate: 2015-04-01
       
  • A nanostructure-based electrochemical sensor for square wave voltammetric
           determination of N- acetylcysteine in pharmaceutical and biological
           samples
    • Abstract: Abstract In this study, a carbon paste electrode (CPE) was chemically modified with Pt/carbon nanotubes (CNTs) nanocomposite and 8,9-dihydroxy-7-methyl-12H-benzothiazolo [2,3-b] quinazolin-12-one (DMBQ). The synthesized nanocomposite was characterized with different methods such as transmission electron microscopy (TEM) and X-ray diffraction (XRD). The modified electrode was used as an electrochemical sensor for the determination of trace amounts of N-acetylcysteine (N-AC). The propose sensor showed very efficient electrocatalytic activity for the anodic oxidation of N-AC, owing to a substantial decrease in anodic overpotentials. The peak current of square wave voltammograms (SWV) of N-AC increased linearly with its concentration in the range of 0.1–600 μM. The detection limit was 0.07 μM at a signal-to-noise ratio of 3, using square wave voltammetry. The modified electrode has been successfully applied for the assay of N-AC in pharmaceutical and biological samples.
      PubDate: 2015-04-01
       
  • Morphology characterization and failure mechanism investigation of Ag-IPMC
    • Abstract: Abstract In order to prolong the service life and to identify the failure mechanism of ionic polymer metal composites (IPMC), Ag-IPMC strips were prepared and were analyzed experimentally and through simulations to investigate the actuating characteristic of IPMC. The surface morphology of active and inactive Ag-IPMC is characterized by electron microscope to analyze the change rules of surface microstructure before and after the failure of IPMC and study the influence of surface microstructure changes on movement failure. Results indicate that the clad layer of active Ag-IPMC surfaces is prepared well, and the Ag-cladded layer has a good electrical conductivity, which provides an environment of steady electric field for the ion exchange in inophragma; the Ag-cladded layer of Ag-IPMC surfaces is destroyed under the effect of current, making the structure of the clad layer to generate the structure similar to fracture and to increase the contact resistance of Ag-IPMC surfaces, leading to the failure of Ag-IPMC.
      PubDate: 2015-04-01
       
  • Investigation of polyaniline films doped with Co 2+ as the electrode
           material for electrochemical supercapacitors
    • Abstract: Abstract H+ and Co2+ ions co-doped polyaniline were synthesized by cyclic voltammetry onto the stainless steel mesh with various concentrations of cobalt chloride (CoCl2 · 6H2O) in electrolyte. The structure and morphology of polyaniline (PANI) and PANI/Co2+ films were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical properties of PANI and PANI/Co2+ films were investigated by cyclic voltammetry, galvanostatic charge–discharge test, and electrochemical impedance spectroscopy (EIS) in 0.5 mol L−1 H2SO4 electrolyte in a three-electrode system. The PANI/0.3 M Co2+ film shows a larger specific capacitance of 736 F g−1 at a current density of 3 mA/cm2 and lower resistance compared with the pure PANI film. The results indicated that the PANI/Co2+ films are promising material for supercapacitors.
      PubDate: 2015-04-01
       
  • Voltammetric studies on the interaction of epinephrine with DNA base on a
           glassy carbon electrode modified with Au nanoparticles
    • Abstract: Abstract The interaction of epinephrine (EP) with DNA, including double-strand DNA (dsDNA) and single-strand DNA (ssDNA) were investigated both in Mcllvaine buffer solution and on a glassy carbon electrode (GCE) modified with Au nanoparticles (nanoAu/GCE). In pH 7.0 Mcllvaine buffer solution, EP had a sensitive oxidation current peak at 0.162 V (vs. SCE) on the nanoAu/GCE. Factors influencing the interaction in Mcllvaine buffer solution were optimized, and some electrochemical parameters, such as number of electron transferred, the standard rate constant of the electrode reaction (K s) were compared in the presence and absence of DNA. The binding ratio (m) of EP with DNA and the equilibrium constant (β) were also calculated. EP did not interact with DNA via intercalation mode.
      PubDate: 2015-04-01
       
  • Nanosized rare earth cobaltite LaCoO 3 synthesized by urea combustion
           method
    • Abstract: Abstract The structural, magnetic, and electrical properties of nano- and bulk samples of LaCoO3, prepared by a urea combustion method, are investigated in this paper. The structures of phases, calcined at different temperatures, were refined in two different space groups rhombohedral R-3c and monoclinic I2/a, and a good agreement was obtained between the observed and calculated XRD patterns. Magnetic measurements reveal that the magnetic susceptibility increases with reduction in particle size. It is observed that there are two types of mechanisms which govern the conduction in different temperature ranges of these samples, and no single law of conduction fits the entire range of temperature. In high temperature range (200–300 K), Arrhenius law fits well, while in the low temperature region (100–200 K), the conduction is governed by Efros-Shklovskii’s (ES) hopping.
      PubDate: 2015-04-01
       
  • Facile and surfactant-free synthesis of SnO 2 -graphene hybrids as high
           performance anode for lithium-ion batteries
    • Abstract: Abstract A facile microwave-assisted ethylene glycol method is developed to synthesize the SnO2 nanoparticles dispersed on or encapsulated in reduced graphene oxide (SnO2-rGO) hybrids. The morphology, structure, and composition of SnO2-rGO are investigated by scanning electron microscopy, transmission electron microscope, thermo-gravimetric analyzer, X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy. The electrochemical performance of SnO2-rGO as anode materials for lithium-ion batteries was tested by cyclic voltammetry, galvanostatic charge–discharge cycling, and rate capability test. It is found that the SnO2 nanoparticles with a uniform distribution have p-type doping effect with rGO nanosheets. The as-prepared SnO2-rGO hybrids exhibit remarkable lithium storage capacity and cycling stability, and the possible mechanism involved is also discussed. Their capacity is 1222 mAhg−1 in the first cycle and maintains at 700 mAhg−1 after 100 cycles. This good performance can be mainly attributed to the unique nanostructure, good structure stability, more space for volume expansion of SnO2, and mass transfer of Li+ during cycling.
      PubDate: 2015-04-01
       
  • Synthesis, surface characterization and electrochemical properties of
           PVC-based cerium(IV) sulphate ion exchange composite membrane
    • Abstract: Abstract The characterization of polyvinyl chloride (PVC)-based cerium(IV) sulphate (CS) composite membrane was carried out by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The composite membrane with 0.175 g PVC and 0.375 g CS proves good chemical, mechanical and thermal stabilities as well as ion exchange capacity. The Teorell, Meyer and Sievers (TMS) method was used to determine the electrochemical parameters such as transport number, mobility ratio and surface charge density of the membrane. The mobility ratio of various univalent electrolytes depends on the electrolyte concentration and follows the decreasing order LiCl > NaCl > KCl. This membrane may be used for treatment of food industry wastewater as well as desalination of sea and brackish waters.
      PubDate: 2015-04-01
       
  • Hydrothermal synthesis and electrochemical performance of Mn-doped V 6 O
           13 as cathode material for lithium-ion battery
    • Abstract: Abstract MnxV6−xO13 (x = 0.01, 0.02, 0.03, 0.04) were successfully synthesized via a simple hydrothermal method followed by heat-treatment. Both crystal domain size, electronic conductivity and the lithium diffusion coefficient of the MnxV6−xO13 samples were influenced by the doping amount of Mn2+. When x = 0.02, the product was nano-sized particles and exhibited the best electrochemical performance. The enhanced electrochemical performance originated from its higher total conductivity and higher lithium diffusion coefficient.
      PubDate: 2015-04-01
       
  • High sensitive determination of theophylline based on manganese oxide
           nanoparticles/multiwalled carbon nanotube nanocomposite modified electrode
           
    • Abstract: Abstract In this study, the preparation of a glassy carbon electrode (GCE) modified with multiwall carbon nanotubes MnO2 nanoparticles (MWNT MnO2) was developed for electrocatalytic detection of theophylline (TP). Electrochemical behavior of the modified electrode was evaluated by cyclic voltammetry (CV) technique. The modified electrode exhibited good promotion to the electrochemical reaction of TP and greatly enhanced the peak currents by combining the advantages of MWNT and MnO2 nanoparticles. The differential pulse voltammetric (DPV) results indicated that there was a good linear relationship between the anodic peak current and TP concentration in the range from 1.0 × 10−7 to 2.0 × 10−5 M in pH 6.0 phosphate buffer (PB) solution with the detection limit of 1.0 × 10−8 M (S/N = 3) and sensitivity of 4678.2 μA mM−1. Furthermore, the applicability of the sensor for TP analysis in pharmaceutical sample and green tea has been successfully demonstrated.
      PubDate: 2015-04-01
       
  • Low-temperature sintering effects on NASICON-structured LiSn 2 P 3 O 12
           solid electrolytes prepared via citric acid-assisted sol-gel method
    • Abstract: Abstract LiSn2P3O12 with sodium (Na) super ionic conductor (NASICON)-type rhombohedral structure was successfully obtained at low sintering temperature, 600 °C via citric acid-assisted sol-gel method. However, when the sintering temperature increased to 650 °C, triclinic structure coexisted with the rhombohedral structure as confirmed by X-ray diffraction analysis. Conductivity–temperature dependence of all samples were studied using impedance spectroscopy in the temperature range 30 to 500 °C, and bulk, grain boundary and total conductivity increased as the temperature increased. The highest bulk conductivity found was 3.64 × 10−5 S/cm at 500 °C for LiSn2P3O12 sample sintered at 650 °C, and the lowest bulk activation energy at low temperature was 0.008 eV, showing that sintering temperature affect the conductivity value. The voltage stability window for LiSn2P3O12 sample sintered at 600 °C at ambient temperature was up to 4.4 V. These results indicated the suitability of the LiSn2P3O12 to be exploiting further for potential applications as solid electrolytes in electrochemical devices.
      PubDate: 2015-04-01
       
  • Electrooxidation of hydrazine in alkaline medium at carbon paste electrode
           decorated with poly( P -phenylendiamine/ZnO) nanocomposite
    • Abstract: Abstract In this study, poly(P-phenylenediamine/ZnO) (PpPD/ZnO) nanocomposite (NC) under ultrasonic conditions was synthesized and characterized. The presence of zinc oxide nanoparticles changed the morphology of PpPD considerably as confirmed by SEM observations. Hydrazine electrooxidation at novel modified carbon paste electrodes (CPE) with supported NC was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA) techniques. Obtained results showed that the NC increases the surface catalytic activity of CPE toward hydrazine electrooxidation. The electrocatalytic current density increased linearly with hydrazine concentration, and the detection limit and sensitivity are determined to be 24 μM and 0.172 mA cm−2 mM−1, respectively. As revealed by the EIS measurements, the increased conductivity and decreased R ct are owing to the presence of ZnO NPs in the PpPD matrix. The CA results indicated that hydrazine electrooxidation results in higher steady-state current density on CPE/PpDP/ZnO electrode system compared to the CPE/PpDP and CPE electrodes.
      PubDate: 2015-04-01
       
  • AC conductivity and mechanism of conduction study of lithium barium
           pyrophosphate Li 2 BaP 2 O 7 using impedance spectroscopy
    • Abstract: Abstract The Li2BaP2O7 compound has been obtained by the conventional solid-state reaction and characterized by X-ray powder diffraction. The title material crystallizes in the monoclinic system with C2/c space group. Electrical properties of the compound have been studied using complex impedance spectroscopy in the frequency range 200 Hz–5 MHz and temperature range 589–724 K. Temperature dependence of the DC conductivity and modulus was found to obey the Arrhenius law. The obtained values of activation energy are different which confirms that transport in the titled compound is not due to a simple hopping mechanism. AC conductivity measured follows the power-law dependence σ AC ∼ ω s typical for charge transport. Therefore, the experimental results are analyzed with various theoretical models. Temperature dependence of the power law exponent s strongly suggests that tunneling of large polarons is the dominant transport process.
      PubDate: 2015-04-01
       
 
 
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