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  Subjects -> ENGINEERING (Total: 2160 journals)
    - CHEMICAL ENGINEERING (186 journals)
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    - ENGINEERING (1165 journals)
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ENGINEERING (1165 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Grid and Utility Computing     Hybrid Journal  
International Journal of Heat and Fluid Flow     Hybrid Journal   (Followers: 17)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 125)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 8)
International Journal of Hypersonics     Full-text available via subscription   (Followers: 3)
International Journal of Imaging Systems and Technology     Hybrid Journal   (Followers: 2)
International Journal of Impact Engineering     Hybrid Journal   (Followers: 8)
International Journal of Information Acquisition     Hybrid Journal   (Followers: 1)
International Journal of Innovation and Applied Studies     Open Access   (Followers: 3)
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  
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: 8)
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: 3)
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  
International Journal of Nanoscience     Hybrid Journal  
International Journal of Nanotechnology     Hybrid Journal   (Followers: 4)
International Journal of Nanotechnology and Molecular Computation     Full-text available via subscription   (Followers: 3)
International Journal of Navigation and Observation     Open Access   (Followers: 11)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Hybrid Journal  
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: 10)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 3)
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   (Followers: 1)
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 5)
International Journal of Polymer Science     Open Access   (Followers: 20)
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: 3)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 7)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 9)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 3)
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: 2)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 5)
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: 8)
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   (Followers: 1)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 6)
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     Hybrid Journal  
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: 8)
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: 3)
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  
International Scholarly Research Notices     Open Access   (Followers: 236)
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)

  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  [2291 journals]
  • Dielectric and electrical properties of coconut water and distilled water
           
    • Abstract: Abstract The complex relative dielectric function ε *(ω) = ε′ − jε″ of coconut water and distilled water in the frequency range 20 Hz to 2 MHz at different temperatures (303 to 333 K) were measured using a precision LCR meter. The electrical/dielectric properties of the liquid samples were represented in terms of complex relative dielectric function ε *(ω), complex ac conductivity σ*(ω), and complex impedance Z *(ω). All of these presentations were used to explore various processes contributed in the electrical/dielectric properties of the coconut water and distilled water.
      PubDate: 2015-07-24
       
  • Improving the ionic conductivity of NASICON through aliovalent cation
           substitution of Na 3 Zr 2 Si 2 PO 12
    • Abstract: Abstract Doping the zirconium site in NASICON (Na3Zr2Si2PO12) with lower valent cations enhanced the ionic transport of the material. Both Na3.2Zr1.8M0.2Si2PO12 (M=Al3+, Fe3+, Y3+) and Na3.4Zr1.8M0.2Si2PO12 (M=Co2+, Ni2+, Zn2+) exhibited a higher bulk conductivity than undoped Na3Zr2Si2PO12 at room temperature. A decrease in the low temperature activation energy for all doped NASICON was observed, which helped contribute to the higher room temperature conductivity. The lower activation energy and enhanced conductivity of doped materials were a result of alterations in the NASICON structure. The charge imbalance created by aliovalent substitution increased the sodium in the lattice resulting in more charge carriers with better mobility. Furthermore, the conductivity was optimized by the ionic radius of the species in the zirconium site. Ultimately, NASICON doped with a +2 oxidation state cation having an ionic radius of approximately 0.73 Å (Zn and Co) attained a maximum in conductivity. Zn-doped NASICON displayed the greatest room temperature bulk conductivity of 3.75 × 10−3 S/cm, while Co-doped NASICON demonstrated the greatest total conductivity of 1.55 × 10−3 S/cm.
      PubDate: 2015-07-24
       
  • High-performance porous spherical cathode materials based on CaCO 3
           -template synthesis of LiNi 1/3 Co 1/3 Mn 1/3 O 2 for lithium-ion
           batteries
    • Abstract: Abstract The porous spherical LiNi1/3Co1/3Mn1/3O2 has been synthesized using CaCO3-template and a conventional solid-state reaction. The physical and electrochemical properties of the materials are examined by many characterizations including XRD, SEM, EDS, BET, CV, EIS, and galvanostatic charge–discharge cycling. The results indicate that the as-synthesized materials prepared by this new method own a well-ordered layered α-NaFeO2 structure (space group: R-3m (166)). And massively porous channels could be observed in the spherical LiNi1/3Co1/3Mn1/3O2. Compared with the firm-surface spherical LiNi1/3Co1/3Mn1/3O2, the porous spherical material exhibits larger specific surface area and superior electrochemical performances. It delivers a higher initial capacity of 164.0 mAh g−1 at 0.1 C (1 C = 180 mA g−1) between 2.7 and 4.3 V, and 93.5 mAh g−1 is still respectively reached at 20 C. After 100 charge–discharge cycles at 1 C in the range of 2.7–4.3 V, the capacity retention is 95.1 %, indicating excellent cycling stability.
      PubDate: 2015-07-22
       
  • Fabrication and electrochemical behavior of a lithium-sulfur cell with a
           TiO 2 -sulfur-carbon aerogel-based cathode
    • Abstract: Abstract The electrochemical properties of a TiO2-sulfur-carbon aerogel cathode, which was based on a sulfur-carbon aerogel (S-CA) composite and amorphous TiO2, were investigated. The results of cyclic voltammetry measurements indicated that the TiO2-S-CA cathode was highly stable. Further, the results of galvanostatic charge/discharge measurements demonstrated that the capacity retention of a Li–S cell based on this cathode at the end of 100 cycles was 71 % of the initial capacity; in contrast, that of cell based on a S-CA cathode was only 43.9 %. On the basis of these result, various factors for improving the cycling life of cells based on this TiO2-S-CA cathode are discussed. Furthermore, the cell with the TiO2-S-CA cathode exhibited robustness and a high degree of reversibility at different discharge rates. Finally, electrochemical impedance spectroscopy was performed at different discharge states in order to study the effects of the microstructure of the composite cathode on its electrochemical performance.
      PubDate: 2015-07-21
       
  • Highly selective detection of trace Cu 2+ based on
           polyethyleneimine-reduced graphene oxide nanocomposite modified glassy
           carbon electrode
    • Abstract: Abstract Polyethyleneimine-reduced graphene oxide (PEI-RGO) nanocomposites were synthesized via the nucleophilic substitution reactions between the active amine groups in PEI and the surface-exposed epoxy groups in graphene oxide. The nanocomposites combining with nafion were used as the sensing material for the analysis of trace amount of Cu2+ in solution using differential pulse anodic stripping voltammetry (DPASV) and showed specific electrochemical properties. Various experimental parameters that exert influence on deposition and stripping of metal ions, such as pH values, deposition potential, and deposition time, were optimized. Under the optimized parameters, the stripping peaks response increased linearly with increasing concentration of Cu2+ in the ranges of 1 to 70 μmol/L, which was the general feature of the DPASV method for the application of trace metal ion sensing. The limit of detection (S/N = 3) was estimated to be 0.3 μmol/L for Cu2+ and the sensitivity was down to 0.5274 μA/(μmol/L). More importantly, selective detection toward trace Cu2+ was achieved in the presence of other coexisting interfering metal ions.
      PubDate: 2015-07-21
       
  • Performance enforcement of gel polymer electrolyte for lithium ion battery
           with co-doping silicon dioxide and zirconium dioxide nanoparticles
    • Abstract: Abstract In this work, we report a new method to enforce the comprehensive performances of gel polymer electrolyte (GPE) for lithium ion battery. Poly(methyl methacrylate-acrylonitrile-vinyl acetate) [P(MMA-AN-VAc)] is synthesized as polymer matrix. The physical and electrochemical performances of the matrix and the corresponding GPEs, doped with nano-SiO2 and nano-ZrO2 particles individually or simultaneously, are investigated by scanning electron microscopy, thermogravimetry, electrochemical impedance spectroscopy, and charge/discharge test. It is found that the membrane co-doped with 5 wt.% nano-SiO2 + 5 wt.% nano-ZrO2 and the corresponding GPE combine the advantages of those doped individually with 10 wt.% nano-SiO2 or 10 wt.% nano-ZrO2. Accordingly, the comprehensive performances of the membrane and the corresponding GPE, in terms of thermal stability, ionic conductivity, and electrochemical stability on the anode and cathode of lithium ion battery, is enforced by co-doping 5 wt.% nano-SiO2 and 5 wt.% nano-ZrO2.
      PubDate: 2015-07-21
       
  • Chromium substitution effect on structural and electrochemical behavior of
           Li-Cr-Ni-O oxides
    • Abstract: Abstract The chromium-substituted LiCr x Ni1−x O2 oxides were prepared from lithium hydroxide monohydrate (LiOH·H2O), NiO, and Cr2O3. The structure of Li1.5Cr0.5NiO3 phase has been investigated by means of X-ray single crystal and powder diffraction (space group P-3m1, a = 2.9256(1), c = 7.1539(2) Å). The relations between Li1.5Cr0.5NiO3 structure, rhombohedral LiNiO2, and NiO are described by a group-subgroup scheme on the basis of Bärnighausen formalism. Electronic structures were calculated applying the TB-LMTO-ASA 4.7 program. The maximum of electron localization function (ELF) was obtained around the oxygen atoms. Features of the crystal structure of the trigonal Li1.5Cr0.5NiO3 phase cause lower electrode capacity compared to rhombohedral LiNiO2.
      PubDate: 2015-07-16
       
  • A novel LiSnVO 4 anode material for lithium-ion batteries
    • Abstract: Abstract In this work, a new material LiSnVO4 has been prepared via sol-gel method utilizing ammonium metavanadate, acetates of tin and lithium as starting materials, and nitric acid and oxalic acid as complexing agents. The amount of starting materials used has been chosen so that the mole ratio of Li/Sn/V is 1:1:1. The sol-gel precursor has been sintered at 700 °C for 6 h. Based on thermogravimetry analysis (TGA) analysis, the formation mechanism suggested the product to be LiSnVO4. Energy-dispersive X-ray analysis (EDX) reveals the ~1:1 ratio of Sn:V. EDX results agree reasonably with the formation mechanism from TGA analysis that the Sn:V ratio is 1:1. Results from X-ray photoelectron spectroscopy (XPS) indicate that the oxidation states of Li, Sn, and V are +1, +2, and +5, respectively. Since there is no ICDD data available to match the XRD diffractogram of the material obtained, CMPR and powder diffraction data interpretation and indexing program (POWD) softwares have been used to predict the crystal structure system to be tetragonal (similar to that of SnO2). A fabricated LiSnVO4//Li cell can deliver a large initial irreversible discharge capacity of 1270 mAh g−1 and reversible capacity of 305.4 mAh g−1 at the end of second cycle, which drops to 211 mAh g−1 at the end of 53rd cycle. The capacity retention is 69 % with respect to the second discharge capacity.
      PubDate: 2015-07-15
       
  • Phosphoric acid functional UV-cured proton conducting polymer membranes
           for fuel cells
    • Abstract: Abstract This paper reports the preparation and characterization of 10-methacryloyloxydecyl-dihydrogenphosphate (MDP)-based UV-curable proton-conducting polymer membranes (UVcPMs). Poly(ethylene glycol diacrylate) (PEGDA), as cross-linking agent, and N-vinyl-2-pyrrolidone (NVP), as reactive diluent, were used to arrange the mechanical and physical properties of the resulting membrane. The membrane formulation polymerized under UV irradiation and membranes were characterized by using Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA) and electrochemical impedans spectroscopy (EIS). The water uptakes, the volume swelling ratio and ion exchange capacity (IEC) measurement of the membranes were performed. The IEC values increase with an increase in MDP monomer content. Proton conductivities were measured as a function of the weight fraction of MDP content of the membrane. The conductivities are of the order of 10−4–10−3 Scm−1. The morphology of the membranes was also investigated by Atomic Force Microscopy (AFM). MDP-based UV-cured polymers are first reported as polyelectrolyte membranes.
      PubDate: 2015-07-15
       
  • Synthesis and characterization of polyvinyl alcohol/cationic polyurethane
           binder blend as solid polymer electrolyte
    • Abstract: Abstract In the present study, we have fabricated the blends of polyvinyl alcohol (PVA) and cross linked chain extended cationic polyurethane binder (PUB). X-ray diffraction (XRD) reveals that the crystallinity decreases with PUB loading. The hydrogen bonding of PVA and PUB are confirmed by shifting of C=O (1750–1700 cm−1) and N-H resign (1400–1380 cm−1) of Fourier transform infrared spectroscopy (FTIR) spectra. The optical properties of the blend system such as direct and indirect band gap were evaluated by UV absorption spectra. The band gap decreases with the loading of PUB. The miscibility of PUB and PVA blend has been confirmed by differential scanning calorimetry (DSC). It shows a decrease in glass transition (T g) and decomposition temperature (T d), and increase in melting temperature (T m) with PUB loading. The plane morphology of blend was confirmed by scanning electron microscopy (SEM) with better homogeneity (for 50 % PUB loading). The frequency-dependent AC conductivity seems to follow Jonscher power law in which power factor (s) varies in the range 0.74 < s < 0.89. The DC electrical conductivity was calculated from Cole-Cole plot across broadband frequency (50 Hz–10 MHz) and high temperature range (40–120 °C). The temperature-dependent DC conductivity of PVA/PUB blends obey Vogel-Tamman-Fulcher (VTF) equation which demonstrates the electrical conduction in polymer blends was thermally activated.
      PubDate: 2015-07-10
       
  • Voltammetric determination of catechin using single-walled carbon
           nanotubes/poly(hydroxymethylated-3,4-ethylenedioxythiophene) composite
           modified electrode
    • Abstract: Abstract A simple, sensitive, and reliable carboxylic group functionalized single-walled carbon nanotubes (f-SWCNTs)/poly(hydroxymethylated-3,4-ethylenedioxythiophene) (PEDOTM) modified glassy carbon electrode (GCE) was successfully developed for the electrochemical determination of catechin (CAT). In view of the merits of extraordinary conductivity of PEDOTM and excellent electrocatalytic property of f-SWCNTs, the f-SWCNTs/PEDOTM/GCE modified electrode exhibited a strong electrocatalytic activity for the oxidation of CAT. Under optimized conditions, the proposed modified electrode showed a wide linear response for CAT in the concentration range between 0.039 and 40.84 μM, with a low detection limit of 0.013 μM. Furthermore, the modified electrode also exhibited a good reproducibility and long-term stability, as well as high selectivity, which also was a good candidate for the electrochemical detection and analysis of CAT in commercial green tea.
      PubDate: 2015-07-09
       
  • Influence of tin ions on AC conductivity and dielectric features of Li 2
           O–PbO–P 2 O 5 glass system
    • Abstract: Abstract Li2O–PbO–P2O5 glasses mixed with different concentrations of SnO2 (ranging from 0 to 7.0 mol%) were prepared. AC conductivity (σ ac) and dielectric dispersion have been studied. The results were analyzed on the basis of space charge and orientation polarization models. σ ac exhibited the maximal effect, whereas the activation energy for the conductivity demonstrated minimum at 3.0 mol% of SnO2. In the low-temperature region, σ ac is nearly temperature-independent and is varied linearly with frequency. Such behavior is explained based on quantum mechanical tunneling (QMT) model. These results additionally confirm that there is both ionic and electronic originated conductivity in these glasses. The quantitative analysis of these results with the aid of data on optical absorption and IR spectral studies indicated that the network of the glass mixed with 3.0 mol% of SnO2 possessed higher degree of disorder and exhibited maximum conductivity.
      PubDate: 2015-07-07
       
  • Electrochemical determination of levodopa in the presence of ascorbic acid
           by polyglycine/ZnO nanoparticles/multi-walled carbon nanotubes-modified
           carbon paste electrode
    • Abstract: Abstract This work report on electrodeposition of polyglycine microparticles onto zinc oxide (ZnO) nanoparticles/multi-walled carbon nanotube-modified carbon paste electrode surface in order to construction new levodopa (l-dopa) electrochemical sensor. The prepared electrode used for sensitive and selective determination of l-dopa in the presence of ascorbic acid. The electrochemical response of l-dopa on this modified electrode was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The effect of various experimental parameters including pH and scan rate on the voltammetric response of l-dopa was investigated. The results show that the process of oxidation of this compound is adsorption controlled. At the optimum conditions, the concentration of l-dopa was determined by differential pulse voltammetry, and a dynamic linear range of 5.0–500.0 μmol L−1 and detection limit of 0.08 μmol L−1 were obtained. The results of pharmaceutical and human urine samples’ voltammetric analysis showed that using the proposed method, a precise and sensitive electrochemical determination of l-dopa is feasible.
      PubDate: 2015-07-05
       
  • Improved electrochemical performance of Li 1.2 Ni 0.2 Mn 0.6 O 2 cathode
           material with fast ionic conductor Li 3 VO 4 coating
    • Abstract: Abstract Layered lithium-enriched nickel manganese oxides Li1.2Ni0.2Mn0.6O2 have been synthesized and coated by fast ionic conductor Li3VO4 with varying amounts (1, 3, and 5 wt%) in this paper. The effect of Li3VO4 on the physical and electrochemical properties of Li1.2Ni0.2Mn0.6O2 has been discussed through the characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), discharge, cyclic performance, rate capability, and electrochemical impedance spectroscopy (EIS). The discharge capacity and coulomb efficiency of Li1.2Ni0.2Mn0.6O2 in the first cycle have been improved after Li3VO4 coating. And, the 3 wt% Li3VO4-coated Li1.2Ni0.2Mn0.6O2 shows the best discharge capacity (246.8 mAh g−1), capacity retention (97.3 % for 50 cycles), and rate capability (90.4 mAh g−1 at 10 C). Electrochemical impedance spectroscopy (EIS) results show that the R ct of Li1.2Ni0.2Mn0.6O2 electrode decreases after Li3VO4 coating, which is due to high lithium ion diffusion coefficient of Li3VO4, is responsible for superior rate capability.
      PubDate: 2015-07-04
       
  • Application of multi-walled carbon nanotubes modified with boron oxide
           nanoparticles in electrochemistry
    • Abstract: Abstract Multi-walled carbon nanotubes modified with boron oxide nanoparticles (B-MWCNTs) were synthesized onto oxidized silicon substrate upon decay of ethyl alcohol and boric acid in presence of catalyst by means of chemical vapor deposition technique. The B-MWCNTs were characterized using scanning electron microscopy and transmission electron microscopy in combination with electron energy loss spectroscopy. The B-MWCNTs were electrochemically studied using ferrocyanide/ferricyanide, [Fe(CN)6]3−/4− redox system in potassium chloride solution. Furthermore, the response of B-MWCNTs towards oxidation of acetaminophen (AC) to N-acetyl-p-quinoneimine (NAPQI) was also studied in phosphate buffer solution (pH 7.0). The effect of boron oxide nanoparticles on electrochemical response of B-MWCNTs was probed. Therefore, B-MWCNTs were treated with hydrochloric acid for elimination of boron oxide nanoparticles and their electrochemical response towards [Fe(CN)6]3−/4− and AC/NAPQI redox systems was studied. The results demonstrate the strong influence of boron oxide nanoparticles on electrochemical response of B-MWCNTs.
      PubDate: 2015-07-04
       
  • Electrochemical kinetic properties of AB 5 -type hydrogen storage alloys
           with chemically deposited polypyrrole
    • Abstract: Abstract La0.65Ce0.25Pr0.02Nd0.08Ni3.85Mn0.39Co0.73Al0.31 AB5-type alloy was modified via the method of a simple chemical oxidative polymerization of pyrrole (Py) directly occurring on the surface of alloy particles. Field emission scanning electron microscopy and Fourier transform infrared spectroscopy revealed spongy polypyrrole (PPy) films uniformly and continuously deposited on the surface of the alloy particles. The PPy films possessed superior electrochemical redox reversibility, thus facilitating hydrogen protons transferring from electrolyte to electrode interface. Moreover, the PPy films exhibited prominent anti-corrosion properties and reduced the pulverization of the alloy particles. The PPy-coated alloy received remarkable enhancement in rate capability and cyclability compared to those of the bare alloy. Due to the PPy films, the high-rate dischargeability at a discharge current density of 1500 mA g−1 (HRD1500) significantly increased from 18 to 31.6 %, and the capacity retention rate after 200 cycles (S 200) increased from 84.2 to 89.8 %. Meanwhile, the PPy coatings decreased the charge transfer resistance and increased the hydrogen diffusion rate of the alloys, which well conformed with the HRD results.
      PubDate: 2015-07-04
       
  • A novel electrochemical method for ofloxacin determination based on
           interaction of ofloxacin with cupric ion
    • Abstract: Abstract An indirect electrochemical sensing strategy for the determination of ofloxacin (OFL) was developed using cupric ion (Cu2+) as an electrochemical probe. The method was based on the complexation of OFL with Cu2+, which was investigated by UV-visible spectrophotometry and differential pulse voltammetry (DPV). When OFL was added into the electrolyte solution containing Cu2+, the electro-reduction peak current of Cu2+ on glassy carbon electrode (GCE) was decreased. Some influencing factors in terms of pH, quiet time, and reaction time were systematically studied. Under optimal conditions, the Cu2+ reduction peak current difference (ΔI p) before and after adding OFL was found to be linear to the concentration of OFL in the range from 1.0 × 10−7 to 1.0 × 10−4 M. The detection limit (3S/N) was 8.2 × 10−8 M. Moreover, the proposed sensor displayed high selectivity and good reproducibility, which was successfully applied to the detection of OFL in pharmaceutical tablet and chicken fodder.
      PubDate: 2015-07-02
       
  • Novel sodium bismuth sulfide nanostructures: a promising anode materials
           for sodium-ion batteries with high capacity
    • Abstract: Abstract A simple and versatile method for preparation of hierarchical sodium bismuth sulfide (NaBiS2) nanostructures is developed via a simple solvothermal route. They were firstly tested as anode materials for sodium-ion battery. NaBiS2 is found to be characteristic of high capacity and low potential versus Na/Na+, which would be a promising anode material for sodium-ion battery. The NaBiS2 nanoparticles electrode delivers a second discharge capacity of 692.4 mA h g−1 at a current density of 10 mA g−1. A possible electrochemical reaction mechanism was proposed.
      PubDate: 2015-07-01
       
  • Preparation and performance of a composite polyimide/poly(vinylidene
           fluoride- co -hexafluoropropylene)/nano-Al 2 O 3 polymer electrolyte for
           lithium-sulfur cell
    • Abstract: Abstract A novel gel polymer electrolyte (GPE) based on an electrospun polymer membrane of polyimide (PI) activating with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and further coating with nano-Al2O3 was prepared, and its performance for lithium-sulfur (Li-S) cell was investigated. It is found that the Li-S cell using the new GPE enabled achieving a stable discharge capacity of 820 mAh g−1 after more than 100 cycles. This new GPE system with activating with PVDF-HFP and further coating with nano-Al2O3 was capable of upholding the electrolyte solution and can suppress the dissolution of the intermediate products generated during the discharge process and thus improves the performance of Li-S cell.
      PubDate: 2015-07-01
       
  • Thermal and Electrical properties of Ce 0.8−x Gd x Sm 0.2 O
           2−δ materials for SOFC applications
    • Abstract: Abstract Gadolinium and samarium co-doped ceria electrolyte materials Ce0.8−x Gd x Sm0.2O2−δ (x = 0, 0.02, 0.04, 0.06) were prepared by using sol–gel method. The prepared materials were characterized by X-ray diffraction and scanning electron microscopy. The phase identification and the cell parameters were determined by X-ray powder diffraction. Thermal expansion of prepared materials was measured using dilatometric method in the temperature range 30–1000 °C. The thermal expansion increases linearly increasing temperature. The electrical conductivity was measured using impedance spectroscopy. Among the prepared compositions, Ce0.74Gd0.06Sm0.2O2−δ showed higher electrical conductivity and lower activation energy at 450 °C. Which makes suitable as an electrolyte and it may be a promising candidate for as an electrolyte in IT-SOFCs.
      PubDate: 2015-07-01
       
 
 
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