• Journal of Conservation Science
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• v.8 no.1 s.11
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• pp.51-57
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• 1999

Although the mummies of Lee, Myeong-Jung and his wife whose family name is Moon, were buried in similar sites in 1560's, the degree of decay of the dead bodies and antiquities between two people were quite different. This study was focused on the cause of those differences in the view of engineering concept. Granular soil around the study site shows good drainage and such characteristic could be a factor of excellent conservation of dead body. From the physical characteristics of the material containing lime that is considered to be a barrier from water and air, it was observed that the material around dead body of the wife was more compact and denser than that of the husband. This may suggest that the former is better than the latter in keeping away from the water and air. To understand those differences of physical characteristics between two materials containing lime, minerals had to be identified from the two materials. It was revealed that material containing lime around dead body of the wife contains gypsum and more calcite, which could be the reason for better barrier Preventing from water and air than that around the husband.

• Corrosion Science and Technology
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• v.18 no.6
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• pp.277-284
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• 2019

External corrosion control of buried pipe can be achieved by the combination of barrier coating and cathodic protection. Coating damage and deterioration can be induced by many reasons; damage during handling and laying, enhanced failure at low temperatures, failure during commissioning and operation, disbanding due to inadequate surface cleaning, rock penetration during installation and service etc. This work focused on the effect of survey conditions on the reliability of coating flaw detection of buried pipes. The effects of applied voltage and anode location on the detection reliability of coating flaw of buried pipe in soil with the resistivity of ca. 25.8 kΩ·cm were discussed. Higher applied voltage increased the detection reliability, regardless of buried depth, but deeper burial depth reduced the reliability. The location of the anode has influenced on the detection reliability. This behaviour may be induced by the variation of current distribution by the applied voltage and buried depth. From the relationship between the applied voltage and reliability, the needed detection potential to get a desire detection reliability can be calculated to get 100% detection reliability using the derived equation.

• Journal of the Korean Society of Groundwater Environment
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• v.3 no.2
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• pp.95-100
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• 1996

Schlumberger electrical soundings and Coincident loop time-domain electromagnetic soundings were made on the Nanji-do landfill to investigate the nature of fills and the subsurface structure. The measured data were transformed into apparent resistivity values and then inverted in terms of 1-D resistivity models. At 6 points, both measurements were carried out to check the validity of the interpreted subsurface electrical structures. Interpreted layered models from each method show a good agreement. Obtained models show that a conductive zone exist below the shallow resistive zone. Conductive zone, which is considered to be influenced by decomposition of organic waste materials and infiltration of precipitation, is terminated by resistive zone which is considered as basement. Considering the fact that conductive zone extends to the basement and there exist no barrier layers such as clay layers, contaminant plumes are likely to flow into the groundwater directly.

• 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.

• Journal of the Mineralogical Society of Korea
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• v.29 no.2
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• pp.35-45
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• 2016

Clays, which are abundant in nature and eco-friendly, have been utilized throughout human history due to their characteristic physicochemical properties. Recently, a variety of clays such as montmorillonite, kaolinite, sepiolite and layered double hydroxide with or without chemical modification have been extensively studied for potential application in industries. Clays that possess a large specific surface area, high aspect ratio, nanometer sized layer thickness and controllable surface charge could be utilized as polymer fillers after appropriate chemical modifications. These modified clays can improve mechanical and gas barrier properties of polymer materials but also provide sustained antibacterial activity to polymer films. Furthermore, engineered clays can be utilized as scavengers for chemical or biological pollutants in water or soil, because they have desirable adsorption properties and chemical specificity. In this review, we are going to introduce recent researches on engineered clays for potential applications in future industries such as food packaging and environmental remediation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.12 no.2
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• pp.87-90
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• 2006

Thermal and gas adsorption properties were measured for Korean earthenware (onggi) as a step to elucidate its role as food preserving container. Thermal conductivity and diffusivity decreased with increase in porosity while heat capacity depended on the raw soil component rather than porosity. Thermal barrier of the earthenware was generally similar to that of glass. The onggi material could sorb or adsorb a limited amount of water vapor, $CO_2$ and ethylene gases (0.0005 g/g, $17{\mu}g/g$, $2.6{\mu}g/g$, respectively). Thermal and gas adsorption properties of onggi seem to provide unique application area for use as food container and packaging.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.14 no.2
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• pp.189-200
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• 2016

The Republic of Tajikistan has ten former uranium mining sites. The total volume of all tailings is approximately 55 million tonnes, and the covered area is more than 200 hectares. The safe management of legacy uranium mining and tailing sites has become an issue of concern. Depending on the performance requirements and site-specific conditions (location in an arid, semiarid or humid region), a cover system for uranium tailings sites could be constructed using several material layers using both natural and man-made materials. The purpose of this study is to find a feasible cost-effective cover system design for the Degmay uranium tailings site which could provide a long period (100 years) of protection. The HELP computer code was used in the evaluation of potential Degmay cover system designs. As a result of this study, a cover system with 70 cm thick percolation layer, 30 cm thick drainage layer, geomembrane liner and 60 cm thick barrier soil layer is recommended because it minimizes cover thickness and would be the most cost-effective design.

• Tunnel and Underground Space
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• v.29 no.1
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• pp.38-51
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• 2019

Barcelona Basic Model (BBM) can describe not only swelling owing to decrease in effective stress, but also wetting-induced swelling due to decrease in suction. And the BBM can also consider increase in cohesion and apparent preconsolidation stress with suction, and decrease in the apparent preconsolidation stress with temperature. Therefore, the BBM is widely used all over the world to predict and to analyze coupled thermo-hydro-mechanical behavior of bentonite which is considered as buffer materials at the engineered barrier system in the high-level radioactive waste disposal system. However, the BBM is not well known in Korea, so this paper introduce the BBM to Korean rock engineers and geotechnical engineers. In this study, Modified Cam Clay (MCC) model is introduced before all, because the BBM was first developed as an extension of the MCC model to unsaturated soil conditions. Then, the thermo-elasto-plastic version of the BBM is described in detail.

• Journal of the Korean Geotechnical Society
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• v.40 no.2
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• pp.55-64
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• 2024

While shield tunneling has demonstrated stability in international cases, the new Austrian tunneling method (NATM) encounters challenges in urban environments with shallow cover, weathered ground, and high groundwater levels. This paper introduces two typical collapse scenarios observed in urban areas, specifically within weathered bedrock and uncemented sandy soil layers. The collapses are analyzed using six stability evaluation methods, and the results are synthesized to assess the excavation face stability through a hexagonal diagram. The study finds a consistent agreement between the analysis results of the two collapsed tunnel sites and the evaluation outcomes. The employment of the stability evaluation diagram, a comprehensive method that considers the ground characteristics of the target tunnel, proves crucial for ensuring barrier stability during the tunnel design stage. This method is essential for a holistic evaluation, especially when addressing challenging ground conditions in urban settings.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.22-37
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• 2006

The applicability of biobarrier or in situ microbial filter technology for the remediation of groundwater contaminated with chlorinated solvent was investigated through batch microcosm study. The efficiency and rates of reductive dechlorination of tetrachloroethylene (PCE) are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (or worm casting) and peat as a biobarrier medium. The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{12}$ on the reductive dechlorination was investigated. In the absence of biobarrier medium (adsorbent), addition of electron donors stimulated the dechlorination rate of PCE compared to the control experiment (i.e., no electron donor added). Among the treatments, addition of lactate or lactate/benzoate as hydrogen donor exhibited the highest dechlorination rate ($k_1=0.0260{\sim}0.0266\;day^{-1}$). In case of using vermicompost as a biobarrier medium, amendment of lactate/benzoate exhibited the highest dechlorination rate following with a pseudo-first-order degradation rate constant of $k_1=0.0849\;day^{-1}$. In contrast, when Pahokee peat was used as a biobarrier medium, either butyrate or lactate addition exhibited the highest dechlorination rate with $k_1$ values of 0.1092 and $0.1067\;day^{-1}$, respectively. The results of this study showed the potential applicability of in situ biobarrier technology using vermicompost or peat as a barrier material for the remediation of groundwater contaminated with chlorinated solvent.