• 자원환경지질
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• 제53권1호
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• pp.11-21
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• 2020

본 연구는 대수층과 저투수층이 존재하는 단일시스템에서 trichloroethylene (TCE)과 tetrachloroethylene (PCE)의 거동에 대해 1차원 확산 해석해를 사용하여 저투수층의 농도 분포, 대수층과 저투수층의 경계면에서 확산 선속, 그리고 역확산에 의한 대수층의 오염 지속성을 모델링하였다. 모델링에 사용된 해석해는 이전 연구에서 많이 사용되었던 저투수층의 두께가 무한한 조건의 해석해와 본 연구에서 제시한 저투수층의 두께가 유한한 조건을 고려한 해석해를 모두 사용하였다. 제시된 해석해의 타당성을 평가하기 위해 저투수층의 두께가 무한한 조건의 해석해와 Yang et al.(2015)이 개발한 1차원 확산 해석해의 결과를 Nash-Sutcliffe 유효계수(NSE)로 비교하였다. 저투수층의 농도 분포, 확산 선속, 그리고 대수층의 오염 지속성 등 모든 결과에서 무한한 조건의 해석해를 이용하였을 때 과소평가되는 결과를 나타내었다. 그리고 본 연구에서 제시한 해석해의 결과와 Yang et al. (2015)이 개발한 해석해의 결과는 높은 일치성(NSE = 0.99)을 보였다. 본 연구에서 제시한 해석해를 실제 오염된 부지에 효율적으로 적용하기 위해 유효확산계수, 저투수층의 두께, 그리고 확산된 시간을 이용하여 확산 거리(Z_d)라는 용어를 소개하였다. 확산 거리가 0.7 보다 작은 경우 저투수층의 두께가 무한한 조건의 해석해를 사용할 수 있으며, 확산 거리가 0.7 보다 큰 경우 저투수층의 두께가 유한한 확산 해석해를 사용하여야 모델링의 신뢰성을 높일 수 있을 것으로 사료된다.

• 자원환경지질
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• 제53권1호
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• pp.99-110
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• 2020

국외에서는 DNAPL오염부지 정화처리 과정에서 오염된 저투수성 매체를 주요 관리대상으로 고려하며, 저투수성 매체로부터 역확산하는 오염물질과 대수층 오염 지속성에 관한 연구가 활발히 진행되어 왔다. 그러나 국내 지하수 분야에서는 관련 연구가 미비한 실정이기 때문에, 본 논문은 저투수성 매체에서 오염물질의 정확산 및 역확산 현상을 소개하고 대표적인 연구사례를 통해 그 중요성을 제안하고자 한다. 본 논문에서는 저투수성 매체의 경계조건에 따른 6개의 정확산 및 역확산 시나리오와 각각의 시나리오에 사용된 해석해를 제시하였다. FI (forward diffusion into infinite domain)와 BI (back diffusion from infinite domain) 시나리오는 저투수성 매체의 깊이를 무한하게 가정한 경우, 정확산과 역확산 시나리오를 나타내며 과거 대다수의 저투수성 매체와 관련된 연구에서 사용되었다. 최근 연구에서는 저투수성 매체의 깊이를 유한하게 고려하고 있으며, 본 연구에서 사용한 유한 경계에서 정확산 시나리오는 FFN(forward diffusion into finite domain with no flux boundary), 역확산 시나리오는 BFN (back diffusion from finite domain with no flux boundary)이다. 또한 저투수성 매체 하부 경계를 통한 오염물질의 이동이 가능할 때 정확산 시나리오는 FFF (forward diffusion into finite domain with flux boundary), 역확산 시나리오는 BFF (back diffusion from finite domain with flux boundary)에 해당한다. 본 논문에서 제시한 시나리오와 해석해를 사용한 모델링은 저투수성 매체의 깊이 또는 오염 노출 기간 등의 현장 특성에 맞는 오염처리 공법을 선정하는데 기여할 수 있다. 또한 모델링 결과는 대수층의 정화 이후에도 역확산으로 발생하는 오염의 지속기간, 오염 정도 등의 정보를 제공함으로써 보다 효율적인 오염 정화처리에 기여할 것으로 사료된다.

• 자원환경지질
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• 제43권4호
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• pp.359-369
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• 2010

본 연구는 서반부지역(북서부 소지역, 서부 소지역, 남서부 소지역)에 광역상수도용 수원지 개발을 위하여 굴착된 지하수공을 중심으로 대수층 체계를 분류하고, 수리지질 특성을 규명하였다. 북서부 소지역의 대수층 체계는 상부 투수층-상부 저투수층-하부 투수층-하부 저투수층으로 구성되고, 서부 소지역과 남서부 소지역의 대수층 체계는 상부 저투수층-투수층-하부 저투수층으로 구성된다. 투수량계수와 비양수량은 북서부 소지역, 서부 소지역, 남서부 소지역의 순으로 낮아진다. 비양수량과 응회암의 산출 고도는 비교적 높은 반비례 관계(상관계수 -0.848)를 보이며, 이는 응회암이 대수층의 밑바닥 역할을 하기 때문으로 판단된다. 3개 소지역에 대해서 2004년 수마트라 지진에 의한 지하수위 변동 분석결과, 북서부 소지역에서 평균 23.74 cm로 가장 크며, 서부 소지역에서는 평균 9.48 cm이고, 남서부 소지역 에서는 지하수위 변동이 나타나지 않았다. 그리고 지진에 의한 지하수위 변화는 투수량계수 및 비양수량과 정비례관계를 가지는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 가을 학술발표회 논문집
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• pp.545-552
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• 2002

The purpose of this paper is to investigate permeability characteristic of soil-bentonite landfill liner and development of desirable liner system. In this study, permeability tests for soil-bentonite, reactive soil-bentonite and apply bentomat and reactive mat are carried out under the low and high water pressure. According to test result, additional amount of bentonite decreases the coefficient of permeability up to the bentonite mixture ratio of 15%. Therefore, the permeability test for landfill liner's indicated that the use of general water would be in more safe side because the liner system show low permeability duet decrease effect of porous by suspended soild(SS). The permeability of leachate for Zeolite mixture ratio 0, 5, 10% with bentonite mixture ratio 15% showed negligible variation in the permeability with general water. Therefore, Zeolite could be used as a successful that is available purification material for the treatment of leachate, without changing the of landfill liners. Also odious smell could be removed by adding smell amount of Zeolite to the leachate. It was revealed that the bentomat and reactive mat installed in soil-bentonite layer effectively improved the permeability as well as purification of the leachate.

• Preventive Nutrition and Food Science
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• 제21권2호
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• pp.85-89
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• 2016

Omega-3 rich fish oils are extremely labile, thus requiring control of oxidation and off flavor development. A recently proposed emulsification method, layer-by-layer (LbL) deposition, was found to be a plausible method to enhance the characteristics of bioactive ingredients, especially lipids. The present work was designed to test the possibility of enhancing the uptake and utilization of omega-3 fatty acids present in fish oil. The bioavailability of nano-emulsified fish oil was monitored in terms of intestinal absorption as well as skin permeability by using the everted intestinal sac model and Franz cell model. The skin permeability and intestinal absorption characteristics was significantly improved by LbL emulsification with lecithin/chitosan/low methoxypectin. Multilayer encapsulation along with nano-emulsification can be a useful method to deliver biologically active lipids and related components, such as fish oil. The protective effect of this tool from lipid oxidation still needs to be verified.

• 한국농공학회논문집
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• 제48권6호
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• pp.79-85
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• 2006

A simulation was done to analyze the seepage problems due to seawater intrusion through the embedded rock layers on heterogeneous layers of sea-dike. Numerical analysis with SAMTLE(developed by author) was done by taking various relative permeability $ratio(R_r/R_e)$. These results showed, when the sed-dike is newly designed, operated, and maintained considering the safety of sea-dike in seepage problems, these embankment materials are prudently chosen. The permeability of the soil materials, within the range of salinity management in freshwater, is comparatively high, however, the permeability of rock materials for bottom rock layer is low. Therefore, when the relative permeability $ratio(R_r/R_e)$ is bellow 10 it is safety in seepage problems of sea-dike.

• 한국포장학회지
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• 제5권1호
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• pp.37-46
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• 1999

Water vapor permeability of films is commonly calculated from the water vapor transmission rate of the film measured using a permeability cup method which is essentially a gravimetric method. This method was originally developed for petroleum based plastic films with low water vapor permeability. In the case of hydrophilic bio-polymer films, the resistance caused by a stagnant air layer, which is developed between the underside of the film mounted on the cup and the surface of the desiccant saturated salt solution or distilled water, can be significant and, if neglected, ran lead to underestimation of water vapor transmission rates. Therefore, it is necessary to correct water vapor transmission rate data to accurately estimate the water vapor permeability of bio-polymer films.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.805-812
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• 2009

Permeation water resulting in the reclaimed land of waste can possibly cause the second pollution, such as the underground water and environmental pollution. Accordingly, Liner layer has been installed in the reclaimed land of waste to block and purify permeation water and prevent this second pollution. The material used as Liner layer is the one for water resistance and that of less than permeability coefficient $1{\times}10^{-7}cm/sec$ is widely used. As it is very difficult to secure in bulk this natural clay with low permeability around the field, the suitable way to secure low permeable material is that we use blend with good watertighness by mixing it with natural soil which is spread in the site. While this mixed soil which can resist water is commonly used in the site, bentonite mixed soil which is widely used as Liner layer in the reclaimed land of waste is recognized in Liner and durability. In this study, the engineering characteristics of soil-bentonite mixed liner are investigated using the laboratory hydraulic conductivity and uni-axial strength tests. The soil used for the liner is the clay soil located near the site. Mixing ratio of the bentonite which satisfies the requirement of hydraulic conductivity is determined and the optimum mixing ratio of bentonite is recommended for the landfill. After the mixed liner is constructed using the optimum mixing ratio of bentonite, the block samples of the constructed liner are obtained and the strength tests were performed. The hydraulic and strength properties of the liner for construction of the waste landfill were both satisfactory.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권3호
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• pp.42-49
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• 2017

TOUGH2 was used to simulate the migration of $CO_2$ injected into a sandy aquifer. A series of numerical simulations was performed to investigate the effects of a low-permeability layer (LPL) embedded in the aquifer on the injection rate and the pressure distribution of $CO_2$. The results show that the size and location of the LPL greatly affected the spread of $CO_2$. The pressure difference between two points in the aquifer, one each below and above the LPL, increased as the size of the LPL increased, showing a critical value at 200 m, above which the size effect was diminished. The location of the LPL with respect to the injection well also affected the migration of $CO_2$. When the injection well was at the center of the LPL, the injection rate of $CO_2$ decreased by 5.0% compared to the case with no LPL. However, when the injection well was at the edge of the LPL, the injection rate was decreased by only 1.6%. The vertical distance between the injection point and the LPL also affected the injection rate. The closer the LPL was to the injection point, the lower the injection rate was, by up to 8.3%. Conclusively, in planning geologic storage of $CO_2$, the optimal location of the injection well should be determined considering the distribution of the LPL in the aquifer.

• Carbon letters
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• 제1권3_4호
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• pp.133-137
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• 2001

Mesoporous activated carbon fiber (ACF) was prepared from phenolic resin containing a small amount (0.1 wt %) of organic nickel complex through carbonization and steam activation. Microporous ACF as reference sample was also prepared from phenolic resin without agent. In both cases of the mesoporous ACFs and the microporous ACFs, the electric double layer capacitance of the nonaqueous electrolyte (0.5 M $TEABF_4$/PC or 1.0 M $LiClO_4$/PC) was not proportional to the BET specific surface area. This is owing to the low permeability of nonaqueous electrolyte or the low mobility of ion in narrow micropores. However, the mesoporous ACF showed higher double layer capacitance than the microporous (normal) ACF. This result suggests that the presence of many mesopores promotes the formation of effective double layer or the transfer of ion in the micropore.