• Membrane and Water Treatment
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• v.8 no.3
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• pp.259-277
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• 2017

Adsorption is a widely used technique for the removal of dyes from wastewaters by variety of adsorbents. In this work, the main focus is on the potential assessment of anion exchange membrane for the removal of different dyes using batch system and investigation of experimental data by applying various kinetic and thermodynamic models. The removal of anionic dyes i.e., Eosin-B, Eriochrome Black-T and Congo Red by anion exchange membrane BII from aqueous solution was carried out and effect of various parameters such as contact time, membrane dosage, temperature and ionic strength on the percentage removal of anionic dyes was studied. The experimental data was assessed by kinetic models namely pseudo-first-order, pseudo-second-order, Elovich liquid film diffusion, Bangham and the modified Freundlich models equation have been used to analyze the experimental data. These results indicate that the adsorption of these anionic dyes on BII follows pseudo-second-order kinetics with maximum values of regression coefficient (0.992-0.998) for all the systems. The adsorption of dyes was more suitable to be controlled by a liquid film diffusion mechanism. The adsorptive removal of dye Eosin-B and Eriochrome Black-T were decreased with temperature and thermodynamic parameters such as free energy (${\Delta}G^o$), enthalpy (${\Delta}H^o$) and entropy (${\Delta}S^o$) for adsorption of dyes on membrane BII were calculated at 298 K, 308 K and 318 K. The values of enthalpy and entropy were negative for EB and EBT representing that the adsorption of these dyes on BII is physiosorptive and exothermic in nature. Whereas the positive values of enthalpy and entropy for CR adsorption on BII, indicating that its adsorption is endothermic and spontaneous in nature. It is evident from this study that anion exchange membrane has shown good potential for the removal of dyes from aqueous solution and it can be used as adsorbent for dues removal on commercial levels.

• Journal of Electrochemical Science and Technology
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• v.11 no.3
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• pp.282-290
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• 2020

In this article, we report the effect of blended cathode materials on the performance of all-solid-state lithium-ion batteries (ASLBs) with oxide-based organic/inorganic hybrid electrolytes. LiFePO₄ material is good candidates as cathode material in PEO-based solid electrolytes because of their low operating potential of 3.4 V; however, LiFePO₄ suffers from low electric conductivity and low Li ion diffusion rate across the LiFePO₄/FePO₄ interface. Particularly, monoclinic Li₃V₂(PO₄)₃ (LVP) is a well-known high-power-density cathode material due to its rapid ionic diffusion properties. Therefore, the structure, cycling stability, and rate performance of the blended LiFePO₄/Li₃V₂(PO₄)₃ cathode material in ASLBs with oxidebased inorganic/organic-hybrid electrolytes are investigated by using powder X-ray diffraction analysis, field-emission scanning electron microscopy, Brunauer-Emmett-Teller sorption experiments, electrochemical impedance spectroscopy, and galvanostatic measurements.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.3377-3382
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• 2007

In proton exchange membrane fuel cell, the heat is generated at the catalyst layer as result of exothermic electrochemical reaction. This heat increases temperature of gas diffusion layer and membrane whose conductivity is very sensitive to humidity, function of temperature. So it is very important to analysis heat transfer through fuel cell to maintain temperature at specified range. In this paper numerical simulation was done including reversible, irreversible, ionic resistance, water formation loss to source term of energy equation. Results show that irreversible and water formation loss contributes mainly to energy source term and as current density increases, all of energy source terms become increased and Nusselt number is increased as results of more heat generation. Particularly irreversible loss is found to be predominant among the all energy source and water formation at cathode channel influences the temperature distribution of fuel cell greatly.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2583-2588
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• 2013

A new type of solid and gel-state ionics based on siloxane pyridinium iodides was synthesized and used as electrolytes in dye-sensitized solar cells. The resulting electrolytes were characterized by $^1H$ NMR spectroscopy, TGA and diffusion coefficient. The synthesized siloxane pyridinium iodide electrolytes have characteristics of different chain length of siloxane moieties. The ion conductivities were given 2.7-3.2 S/cm. Among the three SiDPIs based electrolytes, DSSC employing the SiDPI2 gives an open circuit voltage of 0.704 V, a short-circuit current of 15.85 $mA/cm^2$ and conversion efficiency of 6.8% under light intensity of 100 $mW/cm^2$. In addition, the performance of the DSSCs showed relatively reasonable compared with the propylpyridinium iodide (PPI) electrolyte.

• Journal of Pharmaceutical Investigation
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• v.33 no.1
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• pp.29-36
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• 2003

Clenbuterol, a selective ${\beta}_2-adrenergic$ receptor stimulant, has been introduced as a potent bronchodilator for patients with bronchial asthma, chronic obstructive bronchial disease, chronic bronchitis and pulmonary emphysema. The percutaneous permeation of clenbuterol was investigated in hairless mouse skin after application of 50/50 buffer(pH 10)/propylene glycol solvent mixture. The enhancing effects of various penetration enhancers such as terpenes, non-ionic surfactants, pyrrolidones, fatty acids and some other enhancers on the permeation of clenbuterol were evaluated using Franz diffusion cell. Among terpenes studied, 1,8-cineole was the most effective enhancer, which increased the permeability of clenbuterol approximately 39.33-fold compared with the control without penetration enhancer, followed by menthone with enhancement ratio of 23.57. Nonionic surfactants did not have significant enhancing effects. N-Lauryl-2-pyrrolidone increased the permeability of clenbuterol approximately 4.51-fold compared with the control. Lauric acid increased the permeability of clenbuterol approximately 35.57-fold with decreasing the lag time from 2.64 to 0.52 hr. Oleic acid, linoleic acid, linolenic acid and capric acid showed enhancement ratio of 22.62, 19.60, 17.45 and 16.51, respectively. $Labrafil^{\circledR}$ enhanced the permeability of clenbuterol 9.24-fold compared with that without enhancer.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.146-150
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• 1998

The total conductivity and oxygen permeation in (Ce1-xZrxO2)0.9(CaO)0.1 solid solutions were measure das a function of temperature and oxygen partial pressure. Empirically, σ at given x and T was expressed essentially by σ=σo2+σeo Po2-1/4, where σo2 and σeo are constant. Applying a standard defect model in which major defects are Cace", Cece' and Vo in ideal solution, we can assign σo2 as the oxide ion conductivity decreases while the electronic conductivity increases with the increase in Zr content. Using the oxide ion and electronic conductivities thus determined, the oxygen permeation flux was calculated for respective Po2 and T conditions at which the measurements were made. The calculated values were found to agree with the observed ones.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.125-128
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• 2007

The influence of Co substitution in B-site at perovskite PSCF($Pr_{0.3}Sr_{0.7}CO_{x}Fe_{(1-x)}O_{3}$) was investigated in this study. The PSCF series exhibits excellent MIEC(mixed ionic electronic conductor) properties. ASR(area specific resistance) of PSCF3737 was 0.137 ${\Omega}{\cdot}cm^{2}$ at $700^{\circ}C$. The activation energy of PSCF3737 was also lower than other compositions of PSCF. ASR of PSCF3737 was analysed as two parts at different part of frequency region. Responses at middle frequency part (${\sim}10^2$ Hz) were concerned with oxygen reduction reaction and those at low frequency part (${\sim}10^{-1}$ Hz) were related with oxygen diffusion.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.58-59
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• 2006

Less than a decade ago, most alternate membrane materials for fuel cells relied upon a post-sulfonation process to generate ionic groups capable of transporting protons from the anode to the cathode. These random post sulfonations showed some promise, but in general they produced materials that were not sufficiently stable or protonically conductive at ion exchange capacities where aqueous swelling could be restricted. Our group began to synthesize disulfonated monomers that could be used to incorporate into random copolymer proton exchange membranes. The expected limitation was that the aromatic polymers might not be stable enough to withstand fuel cell conditions. However, this was mostly based upon an accelerated test known was the Fenton's Reagent Test, which did not seem to this author as being a reliable predictor of performance. A much better approach has been to evaluate the open circuit voltage (OCV) for alternate membranes, as well as the benchmark perfluorosulfonic acid systems. When this is done, the aromatic ionomers of this study, primarily based upon disulfonated polyarylene ether sulfones, show up quite well. Real time 3000 hours DMFC results have also been generated. Obtaining conductive materials at low humidities is another major issue where alternate membranes have not been particularly successful. In order to address this problem, multiblock copolymers with relatively high water diffusion coefficients have been designed, which show promise for conductivity at lowered humidity.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.119-129
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• 1992

The rates of mass transfer with the alkaline hydrolysis of ethyl acetate and n-butyl acetate were measured by using a modified Lewis cell. The rates of mass transfer with chemical reaction were independent of the speed of agitation, and the reaction enhancement factors were independent of the ionic strength. The second order reaction rate constants of ethyl acetate and n-butyl acetate could be obtained from an approximate solution of a diffusion equation by film theory, and their values were $0.041m^3/kg\;mol{\cdot}s$ and $0.338m^3/kgmol{\cdot}s$, respectively.

• Journal of Technologic Dentistry
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• v.33 no.4
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• pp.339-347
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• 2011

Purpose: This study was investigated the bonding strength of two kinds of Ni-Cr alloy with respect to the condition of surface treatment. Methods: The surface treatment was performed on the two kinds of Ni-Cr alloy (B alloy and R alloy) specimens, which were sandblasted with $50{\mu}m$, $110{\mu}m$, and $250{\mu}m$ aluminium oxide and were treated with opaque application (paste and wash opaque). The roughness on the surfaces of the specimens was observed. The metal-ceramic interfaces were analyzed with EPMA in order to ionic diffusion, and the shear test was performed. Results: The BA250 specimen, which has higher surface roughness, showed the highest bonding strength in B specimens. In R specimens, the bonding strength of RA110 specimen was the highest. Conclusion: B specimen formed a mechanical bond between metal-ceramic interfaces; however, in the case of R specimen, a chemical bond was formed between that interfaces. There was no significant statistical difference between the bonding strengths of two types of specimens (p>0.05).