• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.4
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• pp.98-105
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• 1997

Compacted clay materials are often used to form barriers for waste disposal by means of landfill. The performance of clay barrier depends on its permeability characteristics under the site environments. The study discusses permeability characteristics of 4 types of permeants through a compacted clayey soil. Permeabilities are measured using the modified rigid-wall permeater and with water, PEG, Ethanol, and TCE, ranging 80 to 3.4 of dielectric constants. Results of the study are as follows : 1) Absolute permeabilities of Ethanol and TCE that their dielectric constants are lower than that of water are $K=1.0{\times} 10^{-12} cm^2$, and $5.8{\times} 10^{-12} cm^2$, respectively, that is, 1.67, and 9.67 times of permeability of water, respectively. Absolute permeability and dielectric constant of water are $K=6{\times} 10^{-13} cm^2$, and 80, respectively. 2) Changes in absolute permeability of Ethanol and TCE converge to a constant after 3.5 pore volume of permeant flows through the clay sample. This can be explained that diffuse double layer of clay is no longer reacted with permeants and contracted their pores. However there is no change in absolute permeability when water is used as a per-meant. 3) It is found that absolute permeability in reversely proportional to the value of dielectric constant of the permeants. Change in absolute permeability of the permeants with 40 or over of dielectric constant is not significant. However change in absolute permeability of the permeant with 30 or lower dielectric constant is abruptly increased. 4) A lower absolute permeability of PEG is found because of its high viscosity.

• Economic and Environmental Geology
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• v.46 no.4
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• pp.279-289
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• 2013

The most critical factor in developing coalbed methane(CBM) reservoir is absolute permeability. Both productivity and economics of the CBM depend on the absolute permeability. The methods to estimate it are core analysis and well test. However, absolute permeability determined by core analysis cannot be a good representative of CBM reservoir. Therefore, it is generally estimated by well test. In this study, well test methods applicable of CBM reservoir were classified with their characteristics. Merits and demerits of each well tests were also analyzed. Based on those parameters, design considerations and procedures of well test were derived. After each well tests was performed, the procedure of well test interpretations to estimate reservoir properties such as absolute permeability and skin factor was presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.677-682
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• 2000

Porous concrete is defined as d type of concrete for which the fine aggregate component the matrix is entirely omitted. Although it had been used as a building material in Europe for over 60 years, low strength and high void ratio limited its application in the past. In recent years, however high void ratio of concrete has been recognized again and can be used as an environmental conscious material, for example, parking lots, draining light-traffic-volume pavements and as sea water purifying material. The result of an experiment on the void ratio of fiber reinforced porous concrete and its influence on the compressive strength and permeability relationship of concrete are reported in this paper. One-sized coarse aggregate of 5-10mm, and three absolute content of fiber(steel fiber, polyprophylen fiber) were used. The result of measured void ratio, permeability coefficient and compressive strength show a small variation. Void ratio, permeability coefficient and compressive strength of fiber reinforced porous concrete depend on contents of fiber and absolute volume ratios of paste to aggregate.

• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.6
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• pp.80-87
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• 1997

A series of tests was performed to determine a threshold concentration of water-soluble organic permeant(ethanol) for permeability to be increased in clay and to estimate long-term permeability behaviors, effects of overburden pressure and compaction conditions on permeability in clay. Results of study are as follows ; 1. A threshold concentration of water-soluble organic permeant(ethanol) in clay was about 7O~8O% and its dielectric constant was 40, and dielectric constant seems to be closely related with absolute permeability. 2. Permeability of long-term tests was more or less larger than that of short-term tests. 3. Overburden pressures applied for a long time elapsed have little effects on the restriction of permeability increase. 4. Since water content has no effects of compaction capability when it is compacted with OMC or wet side of OMC, its permeability is to be estimated as same level of dry side of OMC. 5. Clays matured in the humid chamber are increased in permeability 2 times larger than unmatured ones. Thixotropy, therefore, should be considered in the design procedures because field conditions of construction would be quite similar to this..

• Journal of Korea Soil Environment Society
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• v.5 no.3
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• pp.35-54
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• 2001

It is difficult to accurately predict each flow rate of landfill gas and leachate extracted from many of wells, which have been completed into a waste landfill containing gas and water. However it may be approximately predicted if we can define only relative fluid permeability of gas and leachate flowing through landfill porous media. Therefore numerical simulation using multi-phase flow equations makes use of ei s input data of the relative permeability which is measured and calculated in laboratory environment like in-situ, and consequently we can quantitatively obtain each flow rate of gas and leachate from collection wells. These series of technologies can provide with the important informations to determine the success or failure of landfill gas energy and landfill stabilization. This paper analyses the characteristics of landfill gas collection by six classes of case studies for none described landfill.

• Computers and Concrete
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• v.13 no.1
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• pp.17-30
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• 2014

This research presents the effect of various ground pozzolanic materials in blended cement concrete on the strength and chloride penetration resistance. An experimental investigation dealing with concrete incorporating ground fly ash (GFA), ground bottom ash (GBA) and ground rice husk ash (GRHA). The concretes were mixed by replacing each pozzolan to Ordinary Portland cement at levels of 0%, 10%, 20% and 40% by weight of binder. Three different water to cement ratios (0.35, 0.48 and 0.62) were used and type F superplasticizer was added to keep the required slump. Compressive strength and chloride permeability were determined at the ages of 28, 60, and 90 days. Furthermore, using this experimental database, linear and nonlinear multiple regression techniques were developed to construct a mathematical model of chloride permeability in concretes. Experimental results indicated that the incorporation of GFA, GBA and GRHA as a partial cement replacement significantly improved compressive strength and chloride penetration resistance. The chloride penetration of blended concrete continuously decreases with an increase in pozzolan content up to 40% of cement replacement and yields the highest reduction in the chloride permeability. Compressive strength of concretes incorporating with these pozzolans was obviously higher than those of the control concretes at all ages. In addition, the nonlinear technique gives a higher degree of accuracy than the linear regression based on statistical parameters and provides fairly reasonable absolute fraction of variance ($R^2$) of 0.974 and 0.960 for the charge passed and chloride penetration depth, respectively.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.272-274
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• 2002

The contribution of light in high-energy film dosimetry was examined using six commercially available solid water substitute phantoms. As six commercially available phantoms; RMI-451, Mix-DP, WE211, WE211-Black, PMMA and PMMA Black were evaluated in this study. It is difficult to evaluate the contribution of Cerenkov radiation and the optical permeability to the relative and/or absolute dosimetry using unpacked film in these phantoms. Therefore the contribution of Cerenkov radiation was estimated by the comparison between film densities in the shielded side (shutting off the light) and unshielded sides on a phantom. The effect of optical permeability was measured under ambient light by the time scale method. The results suggest that the use of black colored phantoms may improve the accuracy of dose measurement in film dosimetry.

• Journal of the Korean Geotechnical Society
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• v.25 no.1
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• pp.65-76
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• 2009

The unsaturated characteristics of Korean weathered granite soils have been studied to investigate the influence of saturated permeability, rainfall intensity and soil-water characteristic curve (SWCC) on the slope stability. The upper, average and lower SWCCs were estimated from the publication and experimental results using the statistical concept. The roughly estimated SWCC can be used for the soils without experimental results by relating SWCC with the particle size distribution curve. An appropriate ratio between the saturated permeability and the rainfall intensity ($k_s$/i) was also suggested for practical use in designing the slopes by investigating the time-dependent variation of slope instability during the rainfall. The slope stability was deteriorated from the initiation of rainfall and recovered again after the factor of safety reached the critical value. The FS of the slope decreased at first and then increased after reaching the critical value during the rainfall. As a result, the slope instability was not related with an absolute rainfall intensity but with the ratio between the saturated permeability and the rainfall intensity. In case of the upper SWCC, the critical condition occurred when the ratio between the saturated permeability and the rainfall intensity was in the range of $1.0{\sim}2.0$.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.11 no.1
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• pp.95-105
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• 2007

A mathematical modeling for the drying process of hygroscopic porous media, such as wood, has been developed in the past decades. The governing equations for wood drying consist of three conservation equations with respect to the three state variables, moisture content, temperature and air density. They are involving simultaneous, highly coupled heat and mass transfer phenomena. In recent, the equations were extended to account for material heterogeneity through the density of the wood and via the density variation of the material process, capillary pressure, absolute permeability, bound water diffusivity and effective thermal conductivity. In this paper, we investigate the drying behavior for the three primary variables of the drying process in terms of control volume finite element method to the heterogeneous transport model on one-dimensional grid.

• Bulletin of the Korean Chemical Society
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• v.4 no.3
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• pp.128-132
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• 1983

The self-diffusion experiment of water was performed across two series of tactic poly(2-hydroxyethyl methacrylate), P(HEMA) membranes prepared by crosslinking with various amount of hexamethylene diisocyanate (HMDIC). The tagging material was tritium hydroxide (THO) and the efflux of THO was counted on a Liquid Scintillation Counter. The transport data of THO show that the permeability decreases as the amount of HMDIC increased from 2.5 to 10 mole % and the self-diffusions coefficient shows a parallel trend with it. The diffusivity data was discussed in terms of the change of water structural orderliness within membranes. Using the relation between viscosities and diffusivities derived from Eyring's absolute rate theory, the corresponding viscosities of water within two series of tactic P(HEMA) membranes were obtained. From this, it is seen that the viscosity of water within tactic P(HEMA) membranes may have the same values with those of supercooling water whose temperature ranges from -28 to -$36^{\circ}C.$.