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  Subjects -> ENGINEERING (Total: 2153 journals)
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ENGINEERING (1172 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 232)
International Journal of Heavy Vehicle Systems     Hybrid Journal   (Followers: 6)
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: 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: 8)
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: 10)
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: 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: 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   (Followers: 1)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 5)
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  
International Scholarly Research Notices     Open Access   (Followers: 222)
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)

  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]
  • Synthesis and characterization of spinel LiMn 2 O 4 nanoparticles prepared
           by high-energy milling and hydrothermal method
    • Abstract: Abstract Spinel LiMn2O4 has been known to be a technologically important, environmental-friendly, and low-cost cathode material used in Li-based rechargeable batteries, and it is also widely available. Nanoparticle spinel LiMn2O4 has been synthesized by the top-down, high-energy milling, and hydrothermal methods. SEM images, X-ray diffraction patterns, and neutron high-resolution powder diffraction patterns have confirmed the nanocrystalline nature of the spinel LiMn2O4 samples. Raman and Fourier transform infrared (FTIR) measurements show typical absorption and vibration spectra typical for the spinel LiMn2O4 showing the formation of various metallic bonds in the sample. The strongest Raman and FTIR signals come from the higher frequency region, with weaker signals appearing in the lower frequency range.
      PubDate: 2015-05-02
       
  • Investigation on the electro-osmotic drag coefficient of Nafion/SiO 2
           composite membranes with different SiO 2 contents
    • Abstract: Electro-osmotic drag of the proton exchange membrane is significant in an operating proton exchange membrane fuel cell because it directly affects water management and fuel cell system. In this paper, a method using a hydrogen pump cell to measure the electro-osmotic drag (EOD) coefficient of Nafion212/SiO2 composite membranes with different SiO2 contents is described. It is found that the EOD coefficient of Nafion212/SiO2 composite membranes decreases with the increase of SiO2 content in the composite membranes and increases with the increase of cell temperature but remains essentially constant for various levels of applied currents. An empirical equation of the EOD coefficient of Nafion212/SiO2 composite membranes as a function of SiO2 content and temperature is proposed through numerical fitting while the temperature ranges from 323 to 363 K and SiO2 content in the composite membranes ranges from 0 to 19.8 %. These works will provide relative parameters for the numerical study on the proton exchange membrane fuel cell based on Nafion212/SiO2 composite membranes. Highlights • We measure EOD of Nafion212/SiO2 composite membranes by using the hydrogen pump cell method under a similar condition to operating proton exchange membrane fuel cell (PEMFC). • The EOD coefficient of Nafion212/SiO2 composite membranes decreases with the increase of SiO2 content within Nafion212/SiO2 composite membranes. • The EOD coefficient of Nafion212/SiO2 composite membranes increases with the increase of the cell temperature. • We obtain empirical equation of the EOD coefficient of Nafion212/SiO2 composite membranes as a function of SiO2 content and temperature through numerical fitting while the temperature ranges from 323 to 363 K and SiO2 content in the composite membranes ranges from 0 to 19.8 %.
      PubDate: 2015-05-02
       
  • Improved rate performance of LiNi 0.5 Mn 1.5 O 4 cathode for lithium ion
           battery by carbon coating
    • Abstract: Abstract Carbon-coated LiNi0.5Mn1.5O4 cathode was prepared using phenolic resin as a carbon precursor. The morphology and structure of the prepared samples were characterized by powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and thermogravimetry, and its performance as cathode of lithium ion battery was investigated by electrochemical impedance spectroscopy and charge-discharge test. The results showed that the carbon coating with phenolic resin as precursor could obviously promote the discharge capacity of LiNi0.5Mn1.5O4 cathode, especially at high rate. At 20 C rate, the discharge capacity is 41 mAh∙g-1 for uncoated LiNi0.5Mn1.5O4, while 108 mAh∙g-1 for carbon-coated LiNi0.5Mn1.5O4. The coated sample also exhibited excellent cyclic performance, remaining 95 % of its initial discharge capacity (131 mAh∙g-1) at 1 C rate after 100 cycles. The interfacial resistance of LiNi0.5Mn1.5O4 with carbon coating was reduced from 90 to 31 Ω.
      PubDate: 2015-05-01
       
  • Study of Study of electrical properties of gallium-doped lithium titanium
           aluminum phosphate compounds
    • Abstract: Abstract Effect of doping gallium is studied, and thereby, its consequence on the electrical properties of lithium-based Li1.3Al0.3 − x Ga x Ti1.7(PO4)3 (LAGTP) system (where x = 0.01, 0.03, 0.05, and 0.07) is reported. X-ray diffraction (XRD) data is used to interpret the micro-structural properties. Electrical properties of Li+ ion are studied using impedance spectroscopy in the microwave frequency range of 32 MHz to 1 Hz. The effect on Li+ conductivity was studied in a temperature range 303 to 423 K. It was found that the gallium doping enhanced the conductivity of Li+ ions. The maximum Li+ conductivity of ∼4 × 10−3 S/cm was observed for gallium-doped samples at 413 K. The factors affecting the Li+ conductivity are discussed using the results from XRD patterns and impedance spectroscopy.
      PubDate: 2015-05-01
       
  • Fabrication and characterization of non-enzymatic glucose sensor based on
           bimetallic hollow Ag/Pt nanoparticles prepared by galvanic replacement
           reaction
    • Abstract: Abstract A non-enzymatic glucose sensor was successfully fabricated by immobilization of bimetallic hollow Ag/Pt nanoparticles (BH-Ag/Pt NPs) using the galvanic replacement reaction onto the surface of the pretreated pure Au electrode. The morphology and composition of the BH-Ag/Pt NPs were investigated by high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD), which proved the formation of bimetallic hollow Ag/Pt nanoparticles. The electroactive surface area and interface property of the Au electrode modified by BH-Ag/Pt NPs were measured by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The associated calculated values were 0.210 cm2 and 11.30 Ω cm2, which were distinctly higher than those of the pure Au electrode. The electrocatalytic properties of the modified electrode toward glucose oxidation were evaluated by CV and differential pulse voltammetry (DPV). The results showed that the modified electrode had a high electrocatalytic activity toward glucose oxidation, a linear response to the glucose concentrations ranging from 1 to 12 mM covering the physiological level of 3–8 mM with a current sensitivity of 7 μA mM−1 and a low detection limit of 0.013 mM. Moreover, the modified electrode also showed ideal reproducibility, long-term stability, and high selectivity. It also showed good glucometer test values for real samples. Therefore, both of the facile preparation method and the excellent properties of the Au electrode modified by BH-Ag/Pt NPs could potentially be implemented to develop novel non-enzymatic glucose sensors.
      PubDate: 2015-05-01
       
  • Synthesis of PtNFs/PANI/NG with enhanced electrocatalytic activity towards
           methanol oxidation
    • Abstract: A novel Pt nanoflowers/polyaniline/nitrogen-doped graphene (PtNFs/PANI/NG) electrocatalyst was prepared by dispersing Pt nanoflowers (PtNFs) onto a polyaniline (PANI) grafted N-doped graphene (NG) matrix through a two-step electrochemical process. Firstly, NG was prepared by a hydrothermal reaction of graphene oxide (GO) with urea, and then electrochemical polymerization of aniline at NG was carried out. Secondly, PtNFs was dispersed onto the film of PANI/NG by electrochemical reduction of H2PtCl6. The as-prepared composites were characterized by SEM, XRD, and Raman spectra. Compared with PtNFs/PANI/G, PtNFs/PANI, and PtNFs/NG catalysts, the novel PtNFs/PANI/NG catalyst exhibits more advantages such as high catalytic activity, excellent poisoning tolerance, and stability characteristic towards methanol electro-oxidation, which is attributed to not only the good dispersion of PtNFs on PANI/NG but also the strong interactions between metal particles and conducting polymer matrixes. The results suggest that the PtNFs/PANI/NG catalyst can be a promising alternative for catalyst in direct methanol fuel cells (DMFCs). Graphical abstract A novel Pt nanoflowers/polyaniline/nitrogen-doped graphene (PtNFs/PANI/NG) composite was developed via electrochemical approach, in which NG cannot only exhibit excellent catalytic activity towards the oxygen reduction reaction and electric conductivity but also effectively improve the stability of PANI. The combination of NG and PANI can improve redox activity of ternary complex film and the successful deposition of Pt on the PANI/NG electrode to form a unique three-dimensional structure of PtNFs. Compared with pure Pt, the incorporation of Pt to the substrate matrices leads to a decrease in the amount of Pt used and an improvement of catalytic activity towards the oxidation of methanol.
      PubDate: 2015-05-01
       
  • Effect of nano SiO 2 on properties of structural, thermal and ionic
           conductivity of 85.32[NaNO 3 ]–14.68[Sr(NO 3 ) 2 ] mixed system
    • Abstract: Abstract In the present study, different mole percent of SiO2 (~10–20 nm) was dispersed into 85.32[NaNO3]–14.68[Sr(NO3)2] mixed system. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and differential scanning calorimetry (DSC) characterizations were carried out on present dispersed system. Alternate current (AC) and direct current (DC) conductivities, dielectric constant, loss, and impedance measurements have been studied in the frequency range from 1 Hz to 10 MHz and in the temperature range from 297 to 553 K. The XRD, FTIR, SEM, and DSC studies of SiO2 dispersed systems reveal the formation of amorphous phase. The frequency dependent ac conductivity follows Jonscher’s universal power law. Dimensionless frequency exponent (n) and dispersion parameter (A) are determined. The enhancement in dc conductivity is observed with the m/o of SiO2 in these electrolyte systems and attains maximum at 20.55 m/o, where from the enhancement starts falling with further increase in m/o, and this enhancement in conductivity is explained using the formation of amorphous phase of ionic salt.
      PubDate: 2015-05-01
       
  • Effect of oxygen activity on semiconducting properties of TiO 2 (rutile)
    • Abstract: Abstract Intensive research aims to reduce the band gap of TiO2-based semiconductors by the incorporation of a range of cations and anions in order to enhance their performance in solar energy conversion. In this work, we show that the band gap, as well as the related semiconducting properties, may be modified by impositions of variable oxygen activity in the oxide lattice instead of doping with extrinsic ions. It is shown that the band gap may be decreased when TiO2 is annealed in strongly reducing conditions [p(O2) ∼10−12 Pa]. The reported data indicate that oxygen activity in the oxide lattice, including TiO2, is the key quantity which must be taken into account in considering compatibility and reproducibility of a range of properties, such as band gap and charge transport.
      PubDate: 2015-05-01
       
  • Synthesis and catalytic performance of Co 3 O 4 particles with octahedral
           crystal shape
    • Abstract: Abstract With sodium hexametaphosphate ((NaPO3)6) as the inorganic structure-directing agent, the precursor of Co3O4 was obtained by the method of simple liquid precipitation. Then Co3O4 μm particles with octahedral crystal shape were gotten by calcinating the precursor. The physicochemical features of the octahedral Co3O4 particles were characterized by X-ray diffraction (XRD), Fourier transmission infrared spectra (FT–IR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). The catalytic activity of the Co3O4 particles for the decomposition of ammonium perchlorate (AP) was examined. The results showed that the obtained Co3O4 were mainly octahedral structure with different size. The prepared product has a good catalytic performance in thermal decomposition of AP. The results showed that addition of 10 wt% Co3O4 particles decreased the decomposition temperature by 51 °C and increased the heat of decomposition from 605 to 887 J/g.
      PubDate: 2015-05-01
       
  • Improved copper corrosion resistance of epoxy-functionalized hybrid
           sol–gel monolayers by thiosemicarbazide
    • Abstract: Abstract To improve the copper corrosion resistance of epoxy-functionalized hybrid sol–gel monolayers (Hy) consisting of 3-glycidoxypropyltrimethoxysilane (GPTMS-functional monomer) and tetraethoxysilane (TEOS-reticulating agent), the copper surface was modified by a well-defined inhibitor viz., thiosemicarbazide (TSC). At first, the copper surface was activated by TSC monolayers through Cu–S bonds which end up with free tail amino groups. Secondly, Hy monolayers were immobilized on the TSC-modified copper surface via epoxy-amine reaction. The interaction of TSC with copper and Hy was investigated by Fourier transform infrared spectroscopy, which revealed the cleavage of epoxy ring due to the cross-linking reaction with free amino groups of TSC monolayers. The surface morphology of these monolayers was investigated by scanning electron microscopy and atomic force microscopy. The effectiveness of TSC and Hy monolayers on corrosion protection of copper was scrutinized by electrochemical methods viz., potentiodynamic polarization studies and electrochemical impedance spectroscopy techniques. These studies revealed the enhancement of copper corrosion resistance of epoxy-functionalized Hy monolayers by the TSC activation.
      PubDate: 2015-05-01
       
  • Highly enhanced electrochemical responses of rutin by nanostructured Fe 2
           O 3 /RGO composites
    • Abstract: Abstract Fe2O3/reduced graphene oxide (RGO) nanocomposites were prepared by a hydrothermal reduction using Fe(OH)3 and graphene oxide (GO) precursors, which were assembled electrostatically by mixing a negatively charged GO aqueous suspension with a positively charged Fe(OH)3 solution at room temperature. The resulting composites were characterized using XRD, SEM, FTIR, and TGA, and then were used to modify the glassy carbon electrode (GCE). The electrochemical behavior of rutin on different types of electrode was compared, and the Fe2O3/RGO composite enhanced electrochemical catalysis effect on rutin, and suitable for rutin detection with high sensitivity and short response time. After 90 s, under open circuit potential, the linear range was increased from 1.5 × 10−8 to 1.8 × 10−5 M, and the detection limit was reduced to 9.8 × 10−9 M. This method of analysis has high recovery ratio of rutin up to 99.5 %.
      PubDate: 2015-05-01
       
  • First-principle study on lithium intercalated antimonides Ag 3 Sb and Mg 3
           Sb 2
    • Abstract: Abstract First-principle calculations based on density functional theory have been performed to investigate the negative electrode behaviors, structural changes, and electronic and bonding properties of lithium intercalated antimonides Ag3Sb and Mg3Sb2. Initial intercalation of lithium to orthorhombic Ag3Sb led to form cubic Li2AgSb. Lithium insertion to hexagonal Mg3Sb2 results in cubic LiMgSb. Further insertion of lithium with the intercalated compounds Li2AgSb and LiMgSb results in to the formation of alkali antimonide Li3Sb. The structural transformation of both antimonides Ag3Sb and Mg3Sb2 followed by the insertion of Li+ ends with the formation of Li3Sb with cubic phase. The computed band structures along high symmetry directions of the Brillouin zone, and total and partial density of states clearly illustrate that the intercalation of lithium with Ag3Sb and Mg3Sb2 changes their metallic nature into semiconductor. From the charge density calculations, it is observed that the covalent bond nature in the parent phases Ag3Sb and Mg3Sb2 changed into ionic bond in the Li+ intercalated phases Li2AgSb, LiMgSb, and Li3Sb.
      PubDate: 2015-05-01
       
  • Kinetics, isotherm and thermodynamic investigations for the adsorption of
           Co(II) ion onto crystal violet modified amberlite IR-120 resin
    • Abstract: Abstract The adsorption characteristics of crystal violet (CY)-modified amberlite IRA-120 resin for the removal of Co(II) ion from aqueous medium at different experimental conditions were established by means of batch method. The adsorption uptake was increased with the increase in contact time and temperature. The adsorption process was controlled by pseudo-first-order kinetic model. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models. The Freundlich adsorption model fitted the experimental data reasonably well compared to the Langmuir model. A well-known thermodynamic equation was used to assess the ΔG 0 (standard free energy change), ∆H 0 (enthalpy change), and ∆S 0 (entropy change). The thermodynamic data was indicative of the spontaneous nature of the endothermic sorption process of Co(II) ion onto CY-modified amberlite IRA-120 resin.
      PubDate: 2015-05-01
       
  • Ionothermal synthesis for Mg-doped LiMn 1.5 Ni 0.5 O 4 spinel with
           structural stability and high-rate performance
    • Abstract: Abstract The Mg-doped materials are synthesized by a novel ionothermal method using a kind of imidazolium-based ionic liquids as both reaction medium and structure-directing agent and successively followed by a calcination process. The tests show that the Mg-doped materials present uniform particles about 150 nm which are smaller than that of LiNi0.5Mn1.5O4. The result can be mostly due to MgCl2, which restrains the growth of the particles at high temperature. The electrochemical testing results demonstrate LiNi0.49Mg0.01Mn1.5O4 material has the capacity retention of higher than 96.9 % after 100 cycles, and high capacity of 105.3 mAh g−1 at 10 C rate, in comparison with the capacity retention of 91.2 % and capacity of 82.4 mAh g−1 for the pristine one. The excellent rate performance and cycling stability can be attributed to the small and uniform nanostructure, which can make the lithium-ion diffusion and electron transfer more easily across the LiNi0.49Mg0.01Mn1.5O4/electrolyte interfaces.
      PubDate: 2015-05-01
       
  • Free-binder lithium ion battery based on a hybrid multiwalled carbon
           nanotube-graphitic platelet architecture
    • Abstract: Abstract We have developed a novel material with a hybrid multiwalled carbon nanotube–graphitic platelet architecture for lithium ion battery (LIB) anode that requires no additional aggregate and support materials such as polymeric binders and current collectors of copper or aluminum foils. The absence of these inhomogeneous additives signifies a weight increase of the anode active materials, which contributes to charge-discharge capacities and gives rise to increasing energy densities. The as-prepared materials were characterized by scanning electronic microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), and electrochemical measurements. Results reveal that these hybrid architecture materials with multiwalled carbon nanotubes (MWCNTs) and layered and honeycombed graphitic platelets not only show excellent performance as LIB electrode material but also lower the manufacturing costs.
      PubDate: 2015-05-01
       
  • Photoelectrochemical properties of FTO/p-NiO electrode induced by UV light
           irradiation
    • Abstract: Abstract Photoelectrochemical properties of p-nickel oxide (NiO) thin film deposited on fluorine-doped tin oxide (FTO) electrode, by combination of co-precipitation in aqueous media along with the dip-coating process, were investigated by cyclic voltammetry and chronoamperometry techniques in sodium sulfate (Na2SO4) electrolyte solution. The electrochemical characterization measurements have shown that the FTO/p-NiO electrode presents sensitivity to UV light, as observed by the increased photo-induced current, exposed to a more negative potential. The photoelectrochemical parameters obtained were photocurrent response time (∆t 1), photocurrent decay time (∆t 0), and photocurrent density stability (j ph, j light on − j light off). Besides, this electrode shows excellent performance for methylene blue degradation under UV light irradiation condition, with estimated k obs value of 170 × 10−4 min−1, which is nine times higher than the dark condition and about three times higher than NiO powder catalyst. Results presented here allow concluding that the p-NiO thin film stands as an important electrode material with technological potential to be used directly in environmental preservation.
      PubDate: 2015-05-01
       
  • Preparation and lithium storage properties of active
           carbon–CNT/sulfur composite
    • Abstract: Abstract Activated carbon was prepared with active carbon and carbon nanotubes (CNTs) as carriers of sulfur lithium–sulfur battery anode. The preparation was performed by sealing and heating molten lithium–sulfur batteries with different ratios of CNT, which was the positive active material. X-ray diffraction (XRD) pattern showed that composite material had more amorphous structure; the sample of C/CNT ratio of 3:1 exhibited the strongest amorphous, indicating that elemental sulfur was scattered into the pores of the carbon materials. Scanning electron microscopy showed that CNT was evenly dispersed into the activated carbon/sulfur composite materials in the anode material, forming a 3D conductive structure. The discharge specific capacity of the composite test exhibited that a small amount of CNT improved the discharge specific capacity of the anode material to active material for the preparation of activated carbon. The discharge specific capacity of CNT with 2:2 ratio was up to 1371.1 mAh/g. After the first 50 cycles, the discharge specific capacity could be stabilized at 687.3 mAh/g.
      PubDate: 2015-05-01
       
  • Differential pulse voltammetric determination of methyldopa using MWCNTs
           modified glassy carbon decorated with NiFe 2 O 4 nanoparticles
    • Abstract: Abstract A nanosensor was introduced for a sensitive determination of methyldopa using multiwall carbon nanotubes (MWCNTs) decorated with ferrite nickel nanoparticles (NiFe2O4) on a glassy carbon electrode. The electrochemical activity of the modified electrode for the determination of methyldopa was investigated using differential pulse voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy. The results showed that the modified electrode exhibits synergistic activity to the oxidation of methyldopa. The influence of several parameters that affect the response of the modified electrode was studied. A wide linear dynamic range of 0.5 to 900 μmol L−1 methyldopa with a detection limit of 0.08 μmol L−1 was achieved using differential pulse voltammetry. The interference of foreign substances on the selectivity of the electrochemical sensor was evaluated. Finally, the proposed method was successfully applied for the determination of methyldopa in real samples such as human urine, tablet, and plasma with satisfactory results.
      PubDate: 2015-05-01
       
  • Derivative of iota-carrageenan as solid polymer electrolyte
    • Abstract: Abstract A new type of solid polymer electrolyte based on iota (ɩ)-carrageenan derivative has been investigated. ɩ-Carrageenan was reacted with monochloroacetic acid to produce carboxymethyl ɩ-carrageenan. The produced powders were characterized by 1H nuclear magnetic resonance and attenuated total reflection Fourier transform infrared spectroscopy to confirm the substitution of targeted functional in ɩ-carrageenan. The polymer electrolytes films were prepared by solution casting technique. Thermal gravimetric analysis result shows that the modified powder and film were stable up to 300 °C. X-ray diffraction analysis shows that the chemical modification of ɩ-carrageenan increases the amorphous phase of polymer electrolyte film. Meanwhile, the scanning electron microscope observation reveals that the carboxymethyl ɩ-carrageenan film becomes smoother than ɩ-carrageenan film which supports the ionic conductivity enhancement. The ionic conductivity of ɩ-carrageenan film increases from 2.19 × 10−8 to 4.87 × 10−6 S cm−1 after chemical modification of ɩ-carrageenan to carboxymethyl ɩ-carrageenan.
      PubDate: 2015-05-01
       
  • Synthesis and characterization of a novel ferrocenyl-terminated
           percec-type dendron and application for redox batteries
    • Abstract: Abstract A novel ferrocenyl-terminated percec-type dendron 3,4,5-tris (11-ferrocenylundecyloxy) benzoic acid (Fc3CO2H) was synthesized for the first time through nucleophilic substitution reaction between 11-bromoundecyl ferrocene and methyl 3,4,5-trihydroxybenzoate, followed by a hydrolysis process. The structural characteristics of the resultant dendron Fc3CO2H were confirmed through NMR, Fourier transform infrared (FT-IR), and elemental analysis. Furthermore, its stacking structures and physical properties were detected by X-ray diffraction (XRD), thermogravimetry (TG) analysis, differential scanning calorimetry (DSC), and polarized optical microscope (POM). Both cyclic voltammograms (CV) and galvanostatic charge/discharge measurements indicate the as-synthesized dendron has high electrochemical stability and redox reversibility, which makes it a promising candidate for redox batteries.
      PubDate: 2015-04-01
       
 
 
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