• 한국지하수토양환경학회지:지하수토양환경
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• 제15권2호
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• pp.34-39
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• 2010

In this study, the remediation of diesel contaminated soil was attempted with ozone treatment and Fenton reaction. About 10% of initial diesel concentration was removed by the ozone saturated solution. The pseudo-first order decomposition constant of diesel contaminated soil in the presence of 5% of hydrogen peroxide with 1.82, 2.82, 4.82, 6.82, and 11.82% of iron contents was 0.0228, 0.0308, 0.0482, 0.0471, and 0.0592 $min^{-1}$ respectively. The decomposition constant of the diesel was 0.0064 $min^{-1}$ with the addition of ozone saturated solution only. On the addition of ozone saturated solution in the presence of 5% hydrogen peroxide and 5% iron, the decomposition constant of the diesel was 0.0850 $min^{-1}$. These results indicated that the decomposition rate was 190% faster than without the addition of ozone saturated solution. Thus, the application of both ozone and the fenton reaction is promising for the remediation of the diesel contaminated soil.

• 한국토양비료학회지
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• 제44권3호
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• pp.510-516
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• 2011

Salt-affected soils are present in Pakistan in significant quantity. This experiment was conducted to assess the effectiveness of compost for reclamation and compare its efficiency with gypsum. For this purpose, various combinations of compost and gypsum were used to evaluate their efficacy for reclamation. A saline-sodic field having $pH_s$ 8.90, $EC_e$ $5.94dS\;m^{-1}$ and SAR $34.5(mmol\;L^{-1})^{1/2}$, SP (saturation percentage) 42.29% and texture Sandy clay loam, gypsum requirement (GR) $8.75Mg\;ha^{-1}$ was selected for this study. The experiment comprised of seven treatments (control, gypsum alone, compost alone and different combinations of compost and gypsum based on soil gypsum requirements). Inorganic and organic amendments (gypsum and compost) were applied to a saline sodic soil. Rice and wheat crops were grown. Soil samples were collected from each treatment after the harvest of both crops and analyzed for chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) and fertility status (organic matter, available phosphorus and potassium contents) of soil. Results of this study revealed that compost and gypsum improved chemical properties (electrical conductivity, soil reaction and sodium adsorption ratio) of saline sodic soil to the desired levels. Similarly, all parameters of soil fertility like organic matter, available phosphorus and potassium contents were built up with the application of compost and gypsum.

• 한국토양환경학회지
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• 제3권3호
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• pp.75-86
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• 1998

쓰레기매립장에서 복토층을 통하여 대기중에 유출하는 가스를 현장에서 단시간내에 측정이 가능한 밀폐형 chamber법을 제시하였다. 또한, 최종복토층에서의 유출가스 실측치를 모델해석으로 모사하여 다음의 결과를 얻었다. 1) 시간변화에 따른 chamber내(H=10-30 cm)의 농도 변화는 30분이내로, G.C의 분석시간을 고려하여 5분단위로 분석한다. 2)메탄산화 반응의 영향으로 $CH_4$/$CO_2$비가 복토층 표면근처에서 급격히 변화한다. 3)매립지 표면의 flux가 F =$10^{-5}$mol/($m^2$.s)일 경우에는 메탄산화반응에 의해 가스조성에의 영향이 있으나, F =$10^{-6}$moll($\textrm{m}^2$.s)의 경우에는 복토층내의 메탄가스 농도가 상대적으로 적으므로 메탄산화반응에의 영향이 적다.

• 한국토양비료학회지
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• 제48권6호
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• pp.602-609
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• 2015

In order to enhance a biogas production by the hydro-thermal pre-treatment of piggery manure, the effects of hydro-thermal reaction temperature at thermal hydrolysis of piggery manure on the methane potential and anaerobic biodegradability of thermal hydrolysate were analyzed. The increase of hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$ caused the enhancement of hydrolysis efficiency, and most of organic matters were present in soluble forms. However, the methane potentials ($B_u-TCOD$) of hydrolysate were decreased from 0.239 to $0.188Nm^3kg^{-1}-TCOD_{added}$ by increasing hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$, and also the anaerobic biodegradability (DTCOD) decreased from 74.6% to 58.6% with increase of hydro-thermal reaction temperature. The increase of hydro-thermal reaction temperature from $170^{\circ}C$ to $220^{\circ}C$ resulted in the decrease of easily biodegradable organic matter content, while persistent organic matter contents increased.

• 한국CDE학회논문집
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• 제20권3호
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• pp.230-237
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• 2015

Soil deformation on the off-load ground is significantly affected by soil conditions, such as soil type, water content, and etc. Thus, the soil characteristics should be estimated for predicting vehicle movements on the off-load conditions. The plate-sinkage test, a widely-used experimental test for predicting the wheel-soil interaction, provides the soil characteristic parameters from the relationship between soil stress and plate sinkage. In this study, soil stress under the plate-sinkage situation is calculated by the DEM (Discrete Element Method) model. We developed a virtual soil bin with DEM to obtain the vertical reaction forces under the plate pressing the soil surface. Also parametric studies to investigate effects of DEM model parameters, such as, particle density, Young's modulus, dynamic friction, rolling friction, and adhesion, on the characteristic soil parameters were performed.

• 한국산학기술학회논문지
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• 제22권6호
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• pp.267-274
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• 2021

말뚝의 허용횡방향지지력을 결정하는 방법으로는 지반반력법과 극한횡방향지지력에 근거한 방법이 많이 쓰이고 있는데 설계시 지반반력법에 근거한 방법만을 적용하는 경우가 있다. 본 연구에서는 지반조건과 말뚝머리 구속조건 그리고 말뚝길이에 따른 말뚝의 허용지지력을 이들 두 가지 방법을 적용하여 구하고 상호 비교함으로써 해석에서 고려한 조건들이 말뚝의 허용횡방향지지력 결정법에 미치는 영향을 알아보고자 하였다. 연구결과에 따르면 말뚝머리 구속조건 및 말뚝길이에 상관없이 연약 점성토 지반에 설치된 말뚝의 경우 지반반력법에 의한 허용횡방향지지력이 설계를 지배함을 알 수 있었고 점성토의 비배수강도가 커짐에 따라 극한횡방향지지력을 통한 허용횡방향지지력이 설계를 지배함을 알 수 있다. 사질토 지반에 설치된 말뚝의 경우 느슨한 사질토지반에 설치된 말뚝머리 자유인 짧은말뚝의 경우를 제외하고 모든 경우에 있어 극한횡방향지지력을 통한 허용횡방향지지력이 설계를 지배함을 알 수 있다. 횡방향말뚝의 설게시 허용 횡방향변위량에 근거한 설계만으로 충분하다는 견해도 있지만 본 연구결과에 따르면 극한횡방향지지력에 근거한 허용횡방향지지력의 계산 또한 필요함을 알 수 있었다. 수평지반반력계수는 허용횡방향변위량 이내에서는 말뚝폭에 큰 영향을 받지 않음을 알 수 있었으며 실제 많이 쓰이는 말뚝폭의 범위인 20~90cm 인 경우 말뚝폭의 영향을 무시해도 될 것으로 생각된다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 창립총회 및 춘계학술발표회
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• pp.52-55
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• 2000

The effects of environmental conditions, initial dissolved oxygen concentrations, pH, and the presence of electron carrier vitamin B$_{12}$ , on the reduction rate of TNT by Fe$^{0}$ was Quantitatively analyzed using a batch reactor. In all experiments, TNT reduction was best described with a first order reaction and the reduction rate decreased with the increase in the initial DO concentration. However, the specific reaction rate did not decrease linearly with the increase in the initial DO concentration. In the presence of HEPES buffer 0.2 and 2.0 mM(pH 5.7$\pm$0.2), the specific reaction rate increased more than 5.8 times, which showed reduction rate is rather significantly influenced by the pH of the solution. To test the possibility of reaction rate enhancement, well-known electron carrier(or mediator), vitamin B$_{12}$ has augmented besides Fe$^{0}$ . In the presence of 8.0 $\mu\textrm{g}$/L of vitamin B$_{12}$ , the specific reaction rate increased as much as 14.6 times. The results indicate that the addition of trace amount of vitamin B$_{12}$ can be a promising rate controlling option for the removal of organics using a Fe$^{0}$ filled permeable reactive barrier.

• 한국지하수토양환경학회지:지하수토양환경
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• 제25권4호
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• pp.58-66
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• 2020

Since the typical horn-type ultrasonic equipment induces a reaction at the probe tip, the sonochemical reaction has a limitation that it occurs only in a specific area. As one of the ways to overcome this limitation, an ultrasonic device with multi-stepped horn equipped with several oscillators has been developed. The objective of this study was to investigate the sonochemical effects induced by acoustic cavitation system in 20 kHz multi-stepped ultrasonic horn using calorimetry, KI dosimetry and the luminol test. The sonochemical effects of multi-stepped ultrasonic horn were compared with that of the typical horn-type 20 kHz ultrasonic device. The effect of immersion depth and power on the sonochemical reaction was investigated in the ultrasonic system with multi-stepped ultrasonic horn. Higher calorimetric energy was obtained at higher immersion depth and power conditions. Sonochemical effects increased significantly when using the high immersion depth and input power. However, as the input power increased, the cavitation reaction zone concentrated around the ultrasonic horn. Additionally, the experiments to examine the effect of liquid temperature was conducted. The smaller sonochemical reaction was obtained for the higher liquid temperature. The effect on temperature seems to be closely related to liquid conditions such as viscosity and vapor pressure of water.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.124-127
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• 2003

Laboratory scale experiments on in-situ ozonation were carried out to delineate the effects of liquid phases, such as soil water and nonaqeous phase liquid (NAPL) on the transport of gaseous ozone in unsaturated soil. Soil water enhanced the transport of ozone due to water film effect, which prevent direct reaction between soil particles and gaseous ozone, and increased water content reduced the breakthrough time of ozone because of increased average linear velocity of ozone and decreased air-water interface area. Diesel fuel as NAPL also played a similar role with water film, so the breakthrough time of ozone in diesel-contaminated soil was significantly reduced compared with uncontaminated soil. However, ozone breakthrough time was retarded with increased diesel concentration, because of high reactivity of diesel fuel with ozone. In multiphase liquid system of unsaturated soil, the ozone transport was mainly Influenced by nonwetting fluid, diesel fuel in this study.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권2호
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• pp.70-77
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• 2003

유해유기물질의 미생물 분해시 일어나는 총괄반응을 이론적으로 예측하는 방법을 기술하였다. 열역학적 이론을 바탕으로 하는 반쪽반응 방법을 사용하,였고, 최근에 도입된 이론들인 중간체 생성 반응, oxygenation반응, 그룹이론에 의한 표준 자유생성에너지 예측기법 등을 적용하였다. 대표적인 유해유기물질인 phenanthrene과 함께 glucose, hexadecane의 미생물 분해 반응식을 실제로 계산하였다. 예측된 총괄반응식을 이용하여 미생물 수율, 산소 요구량, 질소 요구량, 무기화율 등의 정보를 얻을 수 있었으며, 이는 오염된 지하수/토양의 생물복원 공법 설계 및 자연정화평가 등에 유용하게 적용될 수 있을 것으로 기대한다.