• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.26-27
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• 1995

Most of synthetic polymeric membranes used in ultrafiltration, reverse osmosis and microfiltration processes are prepared by phase inversion(or phase separation) technique. In this technique, a homogeneous polymer solution is cast into thin film or hollow fiber shape and then immersed into a nonsolvent coagulant bath. The exchange of solvent and nonsolvent across the interface between casting solution and coagu!ant can make the casting solution phase-separate and form a membrane with a symmetric or asymmetric structure. Because of importance of this technique in membrane field, many investigations have been dedicated to elucidate the mechanism of membrane formation by phase inversion technique.[1-10] These investigation have suggested that the structure formation and permeation properties of phase inversion membrane depend on the variables such as the nature and content of casting solution and coagulant, temperature of casting solution and coagulant, and the diffusional exchange rate of solvent and nonsolvent etc. which can be related to the thermodynamic and kinetic properties of the casting system. The variables such as the nature and content of casting solution can also be the important factor affecting the structure formation and permeation property of the phase inversion membrane.

• Steel and Composite Structures
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• v.41 no.6
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• pp.873-886
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• 2021

In this paper, an analytical solution for thermodynamic response of functionally graded (FG) sandwich plates resting on variable elastic foundation is performed by using a quasi 3D shear deformation plate theory. The displacement field used in the present study contains undetermined integral terms and involves only four unknown functions with including stretching effect. The FG sandwich plate is considered to be subject to a time harmonic sinusoidal temperature field across its thickness with any combined boundary conditions. Equations of motion are derived from Hamilton's principle. The numerical results are compared with the existing results of quasi-3D shear deformation theories and an excellent agreement is observed. Several numerical examples for fundamental frequency, deflection, stress and variable elastic foundation parameter's analysis of FG sandwich plates are presented and discussed considering different material gradients, layer thickness ratios, thickness-to-length ratios and boundary conditions. The results of the present study reveal that the nature of the elastic foundation, the boundary conditions and the thermodynamic loading affect the response of the FG plate especially in the case of a thick plate.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.546-551
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• 2004

An applying Thermodynamic method for the purpose of measuring hydraulic efficiency of pump-motor system, based on IEC60041 code, is not easy to adopt at field test. Even though there were splendid development in measuring technic in discharge measuring through the hydraulic machina lots of unsolved problems concerned in flow-rate are still remain in measuring hydraulic efficiency in hydraulic machine. The key point in measuring hydraulic efficiency is to measure exact flow-rate. So, Thermodynamic methode provides a good solution. This methode measures hydraulic efficiency by detecting the difference of temperature and pressure between the hydraulic process of machine, without measuring flow-rate of pump or turbine. By measuring temperature in mk level and absolute pressure in pascal, we can get a difference of thermodynamic specific energy in Moliere chart before and after of hydraulic process, md that difference is equal to hydraulic loses. Following the standard in proceeding Thermodynamic methode, I hope these trial and records make others be familiar to the thermal methode and make it easer to beginner for trial.

• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.89-96
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• 2017

This study proposed adsorption of Pb(II) ions from aqueous solution using activated carbon prepared from areca catechu shell (ACS AC) using Timphan Method. The effects of independent variables on adsorption kinetic and isotherm have been investigated by conducting experiments in batch mode at neutral pH. The structural characterization of adsorbent was done by FT-IR and SEM analysis. The Pb(II) adsorption was correlated very well with the pseudo second-order kinetic (PSOKM) and Langmuir isotherm models (LIM). Increasing NaOH mass for activation and adsorption temperature increased weakly all the parameters of adsorption kinetic and isotherm. The Pb(II) ions adsorption capacity of the ACS AC at 27 and $45^{\circ}C$ was 50.51 and 55.25 mg/g, respectively. Thermodynamic parameters were determined, and the results confirmed the Pb(II) ions adsorption should be endothermic and spontaneous process, and both physical and chemical adsorption should be taken place.

• Solar Energy
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• v.9 no.3
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• pp.73-80
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• 1989

This paper presents as assessment based on steady-state thermodynamic analysis and computer modeling of a double effect generation absorption heating cycle for solar air-conditioning to find operating temperature ranges. The influences of component temperatures on the heating coefficients of performance and mass flow ratio have been investigated to obtain optimum operating conditions for the proposed air conditioning system. And the single and double effect absorption cycles are compared with each other over the same range of temperatures.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1029-1035
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• 2014

The protolytic dissociation process of hydrochloric acid (HCl) and hydrofluoric acid (HF) is studied using the B3LYP and MP2 methods with the 6-311+G(d,p) basis set in the gas phase and in aqueous solution. To study the phenomena in detail, discrete and discrete/continuum models were applied by placing water molecules in various positions around the acid. The dissociation process was studied using the thermodynamic cycle involving the structures optimized both in the gas phase and in aqueous solution and was analyzed with two key energy factors, relaxation free energy (${\Delta}G_{Rex(g)}$) and solvation free energy (${\Delta}G_s$). Based on the results, we could understand the dissociation mechanism and wish to propose the best way to study acid dissociation process using the CPCM methodology in aqueous solution.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.99-100
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• 1993

Calorimetric (D.S.C) studies were carried out on the nylon 4,6 single crystals grown from 1,4-butanediol solution at various crystallisation temperatures, based on the assessment of the lamellar thickness by small angle x-ray scattering. Samples were annealed mainly ot get rid of residual solvents inside the crystals. The effect of annealing on the crystal perfection is inferred from the measured thermal properties of the crystals. Accordig to the scanning rates less than 80 K/min., D. S C. melting peaks indicate that changes in the internal morphology of nylon 4,6 crystals preapred at different crystallisation temeratures yield a thermodynamic melting temperature. Tm, of 319 $^{\circ}C$, for the infinitely extended crystal thickness (1/ι). The obtained heat of fusion value for the inginite crystal thickness, Ho, was 270 J/g from the plot of measured feat of fusion ($\Delta$Hm) vs. reciprocal crystal thickness (1/ι). based on these values, the fold surface energy, $\delta$e. of 65.4 erg/$\textrm{cm}^2$ was obtained from Hoffman-Waeeks equation. The thermodynamic melting temperature and heat of fusion of the infinite crystal thickness for the solution grow nylon 4,6 single crystals are found to be higher than of the reported corresponding solution grown nylon 6,6 single crystals. pbtained crystallinity from D. S. C measurements ranges from 40 to 50 %, which is close to the reported yalue for the nylon 6,6 single ctystals but lower than we expected.

• Journal of the Korean Chemical Society
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• v.15 no.3
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• pp.133-145
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• 1971

A method of theoretical calculation of the thermodynamic properties for liquid-vapor interface of binary solution is developed according to the transient state theory of significant liquid structure. The surface tensions, the adsorbed amounts at the liquid-vapor interface and the activity coefficients of the components for the solutions of $C_6H_{12}-C_6H_6$ $CCI_4-C_6H_6$, $CHCl_3-C_6H_6$, $CHCl_3-CCl_4$, $CCl_4-CS_2$ are calculated through the full ranges of the compositions.

• Resources Recycling
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• v.27 no.2
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• pp.63-67
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• 2018

Gibbs free energy is a measure of relative stability among substances. Since the nature of the ions in aqueous solution is diverse, their thermodynamic data at extensive experimental conditions is scarce. In this work, the calculation procedure was introduced to obtain the absolute and conventional standard molar enthalpies and entropies of hydration of ions from the standard enthalpies and entropies of formation of hydrated ions. The application of correspondence principle to estimate thermodynamic data at high temperature was explained.

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1526-1530
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• 2009

Solvent extraction reaction of Zn(II) by Alamine336 from strong HCl solution up to 10 M was identified by analyzing the data reported in the literature. The equilibrium constant of this reaction was estimated by considering the complex formation between zinc and chloride ion. The necessary thermodynamic parameters, such as equilibrium constant for the formation of complexes and the interaction parameters, were evaluated from the thermodynamic data reported in the literature. The following solvent extraction reaction and the equilibrium constant was obtained by considering the activity coefficients of solutes present in the aqueous phase with Bromley equation. $Zn^{2+}\;2Cl^{-}\;+\;R_3NHCl_{org}\;=\;ZnCl_3R_3NH_{org},\;K_{ex}\;=\;6.33\;{\times}\;10^2$ There was a good agreement between measured and calculated distribution coefficients of Zn(II).