• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.33-38
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• 2004

Molecular modeling of gas permeation through zeolite membranes with/without intercrystalline region was carried out. Molecular dynamics (MD) and Monte Carlo (MC) simulations were performed to estimate the diffusion coefficient and adsorption parameters respectively, and our proposed combined method of molecular simulation techniques with a permeation theory (CMP) was used to estimate gas permeability. The calculated permeability of gases (Ar, He, Ne, $N_2$, $0_2$, $CH_4$) at 301 K for the single crystal membrane model was about one order of magnitude larger than the experiential values, although the dependence on the molecular weight of the permeating species agreed with experiments. On the other hand, the estimated permeability using the diffusivity and adsorption parameters of the intercrystalline region model was in good agreement with the experiments. The consistency between experiments and the estimated values means the importance of considering the intercrystalline region and the validity of CMP method to predict the performance of zeolite membranes.

• Magazine of the Korean Society of Agricultural Engineers
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• v.35 no.3
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• pp.130-139
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• 1993

In order to evaluate the long-term permeability performace of the geotextiles, for five different combination of geotextiles and soils the long-term column test method The results obtained are as follows; 1.The gradient range of the initial stage of the long-term permeability curves varied with respect to the soil types, while that of the final stage varied according to the interaction of the soil/geotextile system. 2.The time required for a given soil/geotextile system to reach a interactive stable stage was measured ahout 100 hours for the standard sand and 150 to 600 hours for the silty content soils, respectively. 3.There were no differences between the plain woven geotextile and the non-geotextile in the long-term permeability performance. 4.As the silt content increased, the long-term performance of the geotextiles decreased, and the limiting silt content was about 15%. 5.The thickness and area density of the geotextiles did not influence on the variation of the seepage quantities. 6.The ayerage slope and the transition time of the long-time flow curve were calculated. 7.In order to evaluate the mechanism of soil/geotextile system more perfectly, the gradient ratio test or the hydraulic conductivity test is required.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.414-418
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• 2008

The effects of paper properties such as density, air permeability, water vapor transmission rate on the thermal performance of plate-type enthalpy exchanger were experimentally investigated. Three enthalpy exchanger samples having different properties were made, and were tested according to the standard test procedure (KS B 6879). Effective efficiencies were defined, which accounted for the air leakage between supply and exhaust streams. Results showed that paper density affected the sensible heat transfer of the samples. Sensible heat transfer increased with density of the paper. It was also shown that water vapor transmission rate alone was not a proper indicator for the efficiency of latent heat transfer. Air permeability should also be considered for adequate evaluation of the latent heat transfer. Best performance was obtained for the sample having highest paper density and moderate water vapor transmission ratio.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.325-328
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• 2004

According to demand the increase of the rate of strength development for rapid constructions and repairs, many efforts have progressed to improve on performance of concrete. The use of regulated set cement helps make it possible to increase the rate of strength development. However it has some problems as like increasing its permeability and accelerate its long-term deterioration caused by internal and external factors. The purpose of this study is to improve the performance of regulated set cement, which mixed with the mineral admixtures. In this paper, setting time, compressive/flexural strength and chloride permeability of mortar according to the substitute ratio of SF, FA and BS in the range of $5\~20\%$ were conducted. Based on the test results, 5% substitute of silica fume for binder was showed good performance.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.1012-1018
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• 2006

In this study, the insulation performance of thermal insulation materials such as glass wool, polyetylene and flexible lastomeric foam according to water vapor permeance was estimated by using experimental correlation equation. The results showed the conductivity increment of flexible lastomeric foam which has very low-permeability (${\le}0.15[ng/{\cdot}s{\cdot}Pa]\;or\;{\mu}{\ge}1,000$) is about 50% lower than that of glass wool with the lapse of ten years. The conclusion is that moisture inevitably accumulated in permeable Insulations reduces insulation performance and also accelerates surface condensation in the case of cold water system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.6
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• pp.391-396
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• 2016

Wicks play an important role in determining the thermal performance of heat pipes. Foam-type wicks are known to have good potential for enhancing the capillary performance of conventional types of wicks, and this is because of their high porosity and permeability. In this study, we develop an analytic expression for predicting the permeability of a foam-type wick based on extensive numerical work. The proposed correlation is based on the modified Kozeny-Carman's equation, where the Kozeny-Carman coefficient is given as an exponential function of porosity. The proposed correlations are shown to predict the previous experimental results well for an extensive parametric range. The permeability of the foam-type wick is shown to be significantly higher than that of conventional wicks because of their high porosity.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.111-120
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• 2009

This paper presents a fundamental findings of the functional and structural performance of the porous asphalt concrete coated with MMA resin. To evaluate the structural performance, cantabro, wheel tracking, moisture sensitivity and indirect tensile fatigue tests are performed. The tests results show that the cantabro loss is reduced three times and fatigue resistance is significantly increased after the specimens are coated with MMA resin. However there are little changes in the rutting and moisture damage resistances before and after the coating. Air voids, permeability and BPT(British Pendulum Test) tests are conducted to study the functional performance. It is observed form the tests that the air voids and permeability are slightly decreased after the coating. However, the changes in the air voids and permeability are negligible. The skid resistance of the coated specimens is lower than reference specimens. However, the skid resistance is maintained beyond the level of the reference specimens when silica sands are chipped on top of the coated surface.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.673-676
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• 2009

Non-point pollutants, which mainly originate from high traffic roads and rural areas, contaminate the environment by flowing into various rivers and lakes and thus are of interest as an environmental issue. Accordingly, efforts have been made to design and maintain efficient filter systems for the control of the non-point pollutants. Meanwhile, clay-type materials are widely used for the absorption of chemicals included in pollutants and the absorption performances of various clays have been reported in the literature. Thus, the present study proposes a non-destructive monitoring method for the performance of a clay-type filter using electrical resistivity measurement. A series of experimental tests is performed on celite-based particulate filters with infiltrating non-point source pollutants having the same characteristics as pollutants on high traffic roads. Each test measures permeability, resistivity of the filter materials and resistivity of the filtrated water. As the particulate filter materials filtrate pollutants and absorb heavy chemicals (e.g., $Cr^{6+}$, lead, nickel, among others), ionic concentration increases resulting as the electrical resistivity decrease. When the filter systems approach the end of their lifetime, the electrical resistivity of the filter material converges to a very low value due to lowered filter absorption efficiency. Hence, the electrical resistivity of the filtrated water also converges to a low value due to high concentrations of heavy metals. The permeability converges to a very low value because of significantly reduced porosity due to clogging and absorption of pollutants on the filter material. The experimental results show that electrical resistivity monitoring of filter materials is a promising approach to estimation of filter performance and its life expectancy.

• Journal of the Society of Disaster Information
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• v.18 no.1
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• pp.1-9
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• 2022

Purpose: In this study, we used hydrophilic waterstop used in geosynthetics vertical barrier system to evaluate the performance of impermeability under sealing conditions. Method: ASTM D5887 and ASTM D6766 were applied to determine the capability of the connection during the geosynthetics vertical barrier system. Hydrophilic waterstop was saturated in each solution and the weight, thickness, and volume changes were analyzed over elapsed time. Hydrophilic waterstop was installed at the geosynthetics vertical barrier system connection to evaluate the permeability characteristics. Results: As the expansion reaction time of hydrophilic waterstop increased relatively under saline conditions, the decrease in permeability also showed a smaller decrease in fresh water. Furthermore, the method of engagement of the geosynthetics vertical barrier system showed somewhat better performance of the impermeability due to the large pressure resistance caused by the roll joint type than interlock type. Conclusion: In urban pollutants, which can estimate the outflow of pollutants such as oil storage facilities and industrial complexes, proactive response technologies that can prevent the contaminant diffusion can significantly reduce the damage.

• Journal of Korea Society of Industrial Information Systems
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• v.28 no.6
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• pp.107-113
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• 2023

In the field of ammunition, storage performance is recognized as important, and the moisture-proof performance of packaging containers is very important. In the ammunition field, paper cans with a multi-layered structure are mainly used as packaging containers. It is made by layering materials that play various roles. These packaging containers are mainly evaluated for moisture-proof performance according to the Korean Industrial Standard KS T 1314. The moisture permeability is determined through linear regression analysis of the change in weight of the moisture absorbent added inside. In this study, the effect of the amount of desiccant added on the moisture permeability test results of packaging containers was confirmed. It is considered appropriate that the amount of desiccant used in testing ammunition packaging containers be approximately 70% or more of the internal volume.