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  Subjects -> ENGINEERING (Total: 2167 journals)
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ENGINEERING (1176 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: 15)
International Journal of Heat and Mass Transfer     Hybrid Journal   (Followers: 128)
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     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  
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: 2)
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: 2)
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: 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: 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     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: 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: 221)
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  [2302 journals]
  • Modeling of surface tension for ionic liquids using group method of data
           handling
    • Abstract: The group method of data handling (GMDH) was utilized to estimate the surface tension of 59 ionic liquids. In this regard, an extensive experimental data was selected from literature over the range 268.3 to 532.4 K. The GMDH model can predict the surface tension of ionic liquids by a grand polynomial correlation function of molar density, reduced boiling temperature, reduced temperature and pressure, acentric factor, and critical compressibility factor. The values of the GMDH model showed a very good regression with the experimental data. The average absolute relative deviation (AARD%) of the GMDH model for all ionic liquids was 4.59 % which indicated a good precision in comparison with those obtained from the generalized dimensionless equation, Mousazadeh–Faramarzi equation, and Parachor equation with AARDs% of 10.31, 13.02, and 11.89, respectively.
      PubDate: 2015-06-01
       
  • CN x -modified montmorillonite as support to immobilize Pd and its
           enhanced electrocatalytic activity for formic acid oxidation
    • Abstract: Nature clay, i.e., montmorillonite (MMT), can be used as support materials of anode electrocatalyst in the direct formic acid fuel cell. The nitrogen-containing composite support (MMT-CN x ) was prepared via carbonizing MMT which was covered by polyaniline. Pd/MMT-CN x and Pd/C catalysts were prepared as formic acid oxidation catalysts using an improved liquid reduction method. The composite, structure, surface properties, and electrical conductivity of the supports and catalysts were studied by energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical impedance spectroscopy (EIS). The results showed that well-dispersed Pd nanoparticles with a narrow size distribution of 3.5–5.5 nm could be easily prepared on the MMT-CN x . Larger electrochemical specific area (ECSA) was obtained for Pd/MMT-CN x than Pd/C according to CO-stripping voltammetry. Cyclic voltammetry (CV) and chronoamperometry (CA) measurements showed better catalytic activity and stability of the Pd/MMT-CN x catalyst than the conventional Pd/C catalyst for formic acid electrooxidation. Larger ECSA and doped nitrogen in the support of the Pd/MMT-CN x catalyst may be the main reason of higher activity and better stability for formic acid oxidation compared with the Pd/C catalyst. The results offered potential application of composite support (MMT-CN x ) for the catalyst of the direct formic acid fuel cell.
      PubDate: 2015-06-01
       
  • Carbon coating of Li 4 Ti 5 O 12 -TiO 2 anode by using cetyl trimethyl
           ammonium bromide as dispersant and phenolic resin as carbon precursor
    • Abstract: A new carbon coating method for improving the performance of anode material of lithium ion battery is proposed in this paper. In this method, cetyl trimethyl ammonium bromide (CTAB) is used as dispersant and phenolic resin formed in situ on Li4Ti5O12-TiO2 is used as carbon precursor; thus, uniform coated sample with low carbon content is achieved. Three samples with different carbon contents are prepared, and their carbon content, morphology, structure, and electrochemical performance are investigated by thermogravimetry, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, and charge-discharge test. It is found that the sample with a carbon content of as low as 2.5 wt.% exhibits superior electrochemical performance. It delivers an initial capacity of 162.4 mAh g−1 with capacity retention of 95 % after 200 cycles at 1 C rate. When cycled at a higher rate of 5 C, the sample delivers a capacity of 148 mAh g−1 with no apparent capacity decaying after 90 cycles. The superior performance of the developed anode can be attributed to the uniform carbon coating.
      PubDate: 2015-06-01
       
  • Synthesis and electrochemical investigation of tin dioxide-based elastic
           hollow microspheres for lithium storage
    • Abstract: Elastic hollow SnO2 microspheres are synthesized through a facile templating method. The obtained hollow microspheres have a size of 1–3 μm, which are assembled by lots of nanoparticles of ∼20 nm. The electrochemical performance of the spheres as anode materials for lithium–ion batteries is evaluated. Benefited from the intrinsic structure advantages, the hollow tin dioxide exhibits good electrochemical lithium storage performance with high specific capacity and excellent rate capability. The good electrochemical performance should be reasonably ascribed to the mesoporous and hollow structures, which guarantee vast lithium storage sites, fast lithium–ion insertion/deinsertion, and sufficient void space to buffer the volume expansion. Most importantly, our results provide a new route to prepare hollow SnO2 microspheres and can be applied generally to a wide range of materials.
      PubDate: 2015-06-01
       
  • Ionothermal synthesis and enhanced electrochemical performance of
           nanostructure Cr-doped LiMn 2 O 4 for lithium-ion batteries
    • Abstract: LiCr x Mn2−x O4 (x = 0, 0.02, 0.05, 0.12) materials were effectively synthesized by imidazolium-based ionic liquid as reaction medium at ambient pressure. The morphologies of Cr-doped LiMn2O4 via calcination were characterized by scanning electron microscopy (SEM). SEM reveals that the LiCr0.12Mn1.88O4 sample has regular nanostructure and a uniform particle size of 50–100 nm. Among the four samples prepared in ionic liquid, the charge/discharge tests indicate that LiCr0.12Mn1.88O4 presents the best performance of rate capacity and cycle stability. A typical LiCr0.12Mn1.88O4 delivers the initial discharge capacity of 129.6 mAh g−1 and behaves a quite slow capacity fading with 96.8 % of initial capacity remained after 200 cycles at 0.5 C in the voltage range of 3.4–4.3 V. The improved electrochemical performance can be attributed to Cr doping and recyclable ionothermal method. Furthermore, this ionothermal synthesis is believed to provide a new reaction route for lithium-ion battery materials with mild reaction conditions.
      PubDate: 2015-06-01
       
  • Radioactive tracer application to study the thermodynamics of ion exchange
           reactions using Tulsion A-23 and Indion-454
    • Abstract: In the present investigation, short-lived radioisotopes were applied to study the thermodynamics of ion-isotopic exchange reactions using Tulsion A-23 (nuclear grade) and Indion-454 (non-nuclear grade) anion exchange resins. It was observed during the bromide ion-isotopic exchange reaction using Tulsion A-23 resins that the enthalpy and energy of activation values calculated were 6,831.1 and 9,412.6 J mol−1, respectively, which were less than the respective values of 7,277.9 and 9,859.4 J mol−1 obtained for the same reaction using Indion-454 resins. The identical trend was observed for the two resins during the iodide ion-isotopic exchange reaction. The thermodynamic data suggest that Tulsion A-23 resins were more efficient than Indion-454. This was further confirmed from the fact that under identical experimental conditions higher amount of ions were exchanged using Tulsion A-23 resins as compared to those using Indion-454 resins. The overall results reveal superior performance of Tulsion A-23 over Indion-454 resins under identical experimental conditions.
      PubDate: 2015-06-01
       
  • Sensing behavior of mixed potential NO 2 sensors equipped with LaMO 3
           (M = Fe or Cr) sensing electrodes
    • Abstract: In this paper, yttria-stabilized zirconia (YSZ) electrochemical sensors equipped with a perovskite-type oxide (either LaFeO3 or LaCrO3) sensing electrode (SE) were fabricated and examined in terms of their NO2 sensing properties at high temperatures. A linear correlation was obtained for these devices between the electromotive force (EMF), and the logarithm of the NO2 concentration from 30 to 500 ppm in the temperature range 500–600 °C. The LaFeO3 device proved more sensitive for all temperatures. The variation of the EMF as a function of the O2 concentration at a given NO2 concentration revealed that LaFeO3 has a better catalytic activity to O2 than LaCrO3, leading to larger EMFs.
      PubDate: 2015-06-01
       
  • PtSn nanoparticles supported on iron nanoparticles wrapped inside
           nitrogen-doped carbon for ethanol oxidation
    • Abstract: Iron nanoparticles wrapped in N-doped carbon (INC) were synthesized by a two-step method which includes a hydrothermal and a thermal treatment. The PtSn nanoparticles were then deposited on the resulting carbon material using an ethylene glycol reduction method. Scanning electron microscopy images indicated INC had an interconnected, porous framework with continuous macropores in the micrometer range. Transmission electronic microscopy and X-ray diffraction results proved that the iron nanoparticles were completely wrapped in the N-doped carbon. Cyclic voltammograms for ethanol oxidation showed that the mass activity on PtSn/INC electrode reaches 424.5 mA mg−1 Pt, 1.64 times as large as that for PtSn/C (259.0 mA mg−1 Pt). PtSn/INC also exhibited better durability in ethanol oxidation reaction than PtSn/C. These results indicated that INC is a potential high-performance catalyst support material for fuel cell catalysts.
      PubDate: 2015-06-01
       
  • Floss-like Ni–Co binary hydroxides assembled by whisker-like
           nanowires for high-performance supercapacitor
    • Abstract: Floss-like Ni–Co binary hydroxides (FL-NCOH), assembled by whisker-like nanowires, are synthesized via a facile hydrothermal process with sodium dodecyl benzene sulfonate (SDBS) as the soft template. The forming process of FL-NCOH is clarified by tuning the hydrothermal reaction time. The result indicates that floccule-like nickel–cobalt hydroxide nanoclusters gradually become longer and slenderer nanowires to form FL-NCOH with the increase of reaction time. The dissolution–recrystallization of hydroxide plays an important role in the morphology control of nickel–cobalt hydroxide. The high specific surface area (106.5 m2 g−1) and the suitable 3D structure endow the as-prepared FL-NCOH material high specific capacitance (up to 918.9 F g−1 at the current density of 0.2 A g−1), good high-rate performance (594.2 F g−1 even at 10.0 A g−1), and long cycle life (98.7 % capacitance retention after 3000 charge–discharge cycles at 2.0 A g−1). Graphical ᅟ
      PubDate: 2015-06-01
       
  • Carbon nanotube electrochemical sensor based on and benzofuran derivative
           as a mediator for the determination of levodopa, acetaminophen, and
           tryptophan
    • Abstract: In this research, a (7,8-dihydroxy-3,3,6-trimethyl-3,4-dihydrodibenzo[b,d]furan-1(2H)-one] (DTDF) multi-walled carbon nanotube modified carbon paste electrode was constructed and used as an excellent electrocatalyst in the oxidation of levodopa (LD) in the presence of acetaminophen (AC) and tryptophan (TRP). In the first part of the work, we synthesized DTDF by electrochemically oxidizing the catechol derivative in the presence of dimedone as a nucleophile in an aqueous solution. A modified carbon paste electrode based on this electrosynthesised compound (DTDF) and carbon nanotubes (CNTs) was prepared. Cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. Next, the mediated oxidation of LD at the modified electrode was described. At the optimum pH of 7.0, the oxidation of LD occurs at a potential about 330 mV less positive than that of an unmodified carbon paste electrode. Based on differential pulse voltammetry (DPV), the oxidation of LD exhibited a dynamic range between 1.0 and 1000.0 μM and a detection limit of 0.46 μM. DPV was used for simultaneous determination of LD, AC, and TRP at the modified electrode and quantitation of LD, AC, and TRP in some real samples by the standard addition method.
      PubDate: 2015-06-01
       
  • A cellulose acetate based nanocomposite for photocatalytic degradation of
           methylene blue dye under solar light
    • Abstract: In this work, cellulose acetate–tin (IV) phosphate nanocomposite (CA/TPNC) ion exchanger has been explored for its photocatalytic degradation of methylene blue dye from aqueous solution. The CA/TPNC was characterized using Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and X-ray diffraction (XRD). The ion exchange capacity of nanocomposite ion exchanger was observed to be high (1.48 meq g−1) for Na+ ion as compared to their inorganic counterpart (0.56 meq g−1). The CA/TPNC material was the photocatalytic degradation of methylene blue dye onto CA/TPNC was investigated for 140 min of solar irradiation at 662-nm wavelength. The 80 % the dye was removed onto CA/TPNC after 60 min of irradiation. The rate of photodegradation of MB dye onto CA/TPNC followed the pseudo-first-order kinetic model.
      PubDate: 2015-06-01
       
  • Nanostructured photoelectrochemical solar cells with polyaniline nanobelts
           acting as hole conductors
    • Abstract: Nanostructured photoelectrochemical solar cells have been prepared by combining a Sb2S3-sensitized photoactive electrode, polyaniline nanobelts, and a Ag counter electrode to form a layered structure. Here, Sb2S3 acts as an absorbing semiconductor, and polyaniline acts as both a hole conductor and light absorber (a hole-conducting dye). Via the optimization that eventually determines the chemical bath deposition duration to be 3 h, the cell shows a high photovoltaic performance with 7.05 mA/cm2-short-circuit current density, 0.695 V-open-circuit voltage, 0.457 fill factor, and 2.24 % power conversion efficiency. The prepared devices are stable under room light in ambient conditions (even without encapsulation).
      PubDate: 2015-06-01
       
  • Synthesis of Li 3 V 2 (PO 4 ) 3 /C with enhanced rate performance by a
           two-step technique
    • Abstract: The nano-particles, Li3V2(PO4)3 embedded in carbon matrix, are synthesized by a novel two-step procedure based on a sol–gel method. In the two-step process, the carbon-encapsulated trivalent vanadium phosphorus precursors are obtained without adding lithium compound in the first step. Because of carbon matrix, small particle size of Li3V2(PO4)3/C composite is obtained in the second step, which involves lithiation and heating to 800 °C in argon. The electronic conductivity of Li3V2(PO4)3/C composite is 2.88 × 10−3 S cm−1, increased by five orders of magnitude compared with the pristine Li3V2(PO4)3 (2.3 × 10−8 S cm−1). The prepared Li3V2(PO4)3/C shows high discharge capacity 132 mAh g−1 (3.0–4.3 V), which is up to 99.2 % of the theoretical value, and good high-rate specific discharge capacity, which is greater than 100 mAh g−1 at a rate of 10 C. Even after cycling at 15 C, the charge–discharge performance of the prepared Li3V2(PO4)3/C cathode hardly deteriorates at 1 C indicating that the structure of Li3V2(PO4)3 is not destroyed irreversibly at high rate. The improved electrochemical properties of the Li3V2(PO4)3/C cathode electrodes are also verified by electrochemical impedance spectroscopy.
      PubDate: 2015-06-01
       
  • Electrochemical evaluation and simultaneous determination of binary
           mixture of antihypertensives hydrochlorothiazide and enalapril in combined
           dosage forms using carbon nanotubes paste electrode
    • Abstract: The simultaneous voltammetric determination of binary mixture containing hydrochlorothiazide (HCTZ) and enalapril (ENP) using a multi-walled carbon nanotubes paste (MWCNTsP) electrode is reported for the first time in the literature. Compared with the glassy carbon electrode or carbon paste electrode, MWCNTsP electrode showed excellent responses for the oxidation of HCTZ and especially for ENP. Square-wave voltammetry was used to simultaneous determination of HCTZ and ENP in their binary mixture in BR buffer solution (pH 5.0), which linear calibration curves were obtained in the range of 4.9 × 10−7–4.5 × 10−5 mol L−1 and 5.0 × 10−6–8.3 × 10−5 mol L−1, respectively. The detection limits were found to be 1.4 × 10−8 mol L−1 and 4.1 × 10−8 mol L−1 for the determination of HCTZ and ENP, respectively. The feasibility of the developed method for real sample analysis was investigated and the accuracy checked from analysis by HPLC.
      PubDate: 2015-06-01
       
  • SO 2 gas sensor based on Ag-Ag 2 SO 4 -BaSO 4 sensing electrode
    • Abstract: A sulfur dioxide (SO2) gas sensor based on a novel structural sensing electrode was fabricated. The sensor consists of yttria-stabilized zirconia as the oxygen ion conductor, silver sulfate-based salts as the auxiliary phase, a silver/platinum mixed paste as the sensing electrode/catalyst, and a platinum paste as the reference electrode. Ball milling was employed to decrease the particle size of the silver sulfate-barium sulfate (Ag2SO4-BaSO4) auxiliary phase. After the Ag2SO4-BaSO4 mixture ball-milling for 20 h, the as-obtained sensor showed the highest sensitivity to SO2 gas. Furthermore, in order to optimize the sensing electrode, particles of metallic silver were mixed with silver sulfate-based salts, and the as-designed sensing electrode displayed an improved sensitivity to SO2 gas at a low temperature (400 °C).
      PubDate: 2015-06-01
       
  • Spectroscopic and computational analysis of the molecular interactions in
           the ionic liquid [Emim] + [FAP] −
    • Abstract: A weakly coordinating room-temperature ionic liquid, 1-ethyl-3-methyl imidazolium tris(pentafluoroethyl)- trifluorophosphate ([Emim]+[FAP]−), is investigated by DFT method at B3LYP/6-31+G(d, p) level. Four locally stable conformers of the ion pair were located. Atoms-in-molecules (AIM) and electron density analysis indicated the existence of hydrogen bonds. Further investigation through Natural Bond Orbital (NBO) analysis provided insight into the origin for weaker ion pair interactions. Harmonic vibrations of the ion pair were calculated and compared with the experimental Raman and infrared spectra. Assignments and frequency shifts are discussed in light of the inter-ionic interactions.
      PubDate: 2015-06-01
       
  • Investigation of the structural properties of poly(ethylene oxide)
           copolymer as gel polymer electrolyte and durability test in dye-sensitized
           solar cells
    • Abstract: We investigated the structural and thermal properties of a gel polymer electrolyte prepared with poly(ethylene oxide-co-2-(2-methoxyethoxy)ethyl glycidyl ether) (P(EO/EM) matrix, γ-butyrolactone (GBL), and LiI/I2. Nuclear magnetic resonance spectroscopy measurements were carried out in different temperatures for the aforementioned electrolyte composition in order to understand the interaction between the components of the gel. Within the studied temperature range, the overall Li ion mobility depends on the contribution of the Li ion mobility in GBL molecules and in the polymer matrix. Small angle X-ray scattering (SAXS) measurements of the gel electrolyte indicated an order periodicity of 7–8 nm, which provides evidence for an effective miscibility of GBL and P(EO/EM), since no structural changes were observed by SAXS data (the systems are stable within the studied temperature range). Indeed, this result corroborates Nuclear Magnetic Resonance Spectroscopy (NMR) data, since at room temperature, it is not possible to distinguish magnetic interactions between P(EO-EM) and GBL molecules, indicating the existence of a single phase. Thermogravimetric analysis shows that the gel electrolyte meets thermal stability requirements for application in photoelectrochemical devices. The performance of dye-sensitized solar cells (DSSC) based on this polymer electrolyte with different GBL concentrations was monitored for 30 days. Device with electrolyte containing 30 wt.% of GBL gave the most promising durability results in this study; the performance of this device decreased by less than 10 % in the course of 30 days.
      PubDate: 2015-06-01
       
  • Effect of Ti-doping on the electrochemical performance of lithium
           vanadium(III) phosphate
    • Abstract: Carbon-coated and titanium-substituted lithium vanadium phosphate composites have been successfully prepared through a sol-gel method followed by solid-state reaction under argon. Li3V1.9Ti0.1(PO4)3-C (LVT10PC) and Li3V1.85Ti0.15(PO4)3-C (LVT15PC) were investigated using X-ray powder diffraction, thermal analysis, transmission electron microscopy, cyclic voltammetry, and galvanostatic tests. Different models for the solid solution mechanism in this system are discussed. Electrochemical tests, at a charge-discharge rate of 0.2 C, in the range 2.8–4.4 V show that LVT10PC delivers the highest discharge capacity of 121 mA h g−1 and declines to 115.7 mA h g−1 up to the 60th cycle, corresponding to a 4.4 % loss. At low levels, titanium substitution is found to increase initial discharge capacity compared to the carbon-coated unsubstituted system (LVPC). Further substitution is found to have detrimental effects on initial discharge capacity and cycling behaviour.
      PubDate: 2015-06-01
       
  • Electrochemical determination of tryptophan at room-temperature ionic
           liquid-titanium carbide nanoparticle gel modified electrode
    • Abstract: The novel gel composite, based on the ground of ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate, BMIMPF6) and titanium carbide (TiC) nanoparticles, was used to modify glassy carbon electrode and applied to the electrochemical determination of tryptophan (trp). The physical and electrochemical characterizations of the BMIMPF6-TiC gel modified electrode were studied in detail by scanning electron microscopy, energy dispersive X-ray spectroscopy, cyclic voltammetry, and differential pulse voltammetry methods. Due to the large specific surface area and strong adsorption property of TiC nanoparticles, as well as the good ionic conductivity and strong electrocatalytic property of BMIMPF6, the oxidation peak current of trp at BMIMPF6-TiC gel modified electrode showed good linear relation with its concentrations ranging from 0.50 to 30 μmol/L and 30 to 500 μmol/L, respectively. The detection limit was 0.053 μmol/L. More importantly, the BMIMPF6-TiC gel modified electrode had good anti-interference ability and can be successfully applied in the electrochemical determination of trp in real food samples.
      PubDate: 2015-06-01
       
  • 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
       
 
 
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