• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.141-148
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• 2008

This study was conducted to evaluate the effect of PAC(Powder Activated Carbon) retention time on stable operation of high concentration powered activated carbon(HCPAC-MBR) in the treatment of secondary domestic wastewater. The pilot scale HCPAC-MBR system was operated at two different SRTs, 25 days and 100 days. The main drawback of HCPAC-MBR system was the rapid increase of trans-membrane pressure. The increase rate of trans-membrane pressure was proportional to SRT value at constant flux. This result seemed to be caused by reduced amount of EPS adsorbed on the PAC in the reactor by decreasing the SRT of the PAC. The particle size of the PAC was also influenced by SRT. The PAC size was decreased as SRT was increased. The change of particle size could be one reason for the change of trans-membrane pressure. The pore volume in the cake-layer formed on the membrane surface became to be increased by reducing SRT, because the cake-layer was highly composed of the PAC. Therefore, increased pore volume might play a role to reduce the trans-membrane pressure. The removal rate of E260 and TOC was also inversely proportional to SRT value.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1300-1304
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• 2006

최근 침투형 우수유출저감시설은 물 순환 및 초기우수관리 문제, 치수 목적으로 사용이 증대되고 있으며, 시설 확대를 위한 관련 법규나 기준이 강화되고 있는 실정이다. 본 연구에서는 호우사상에 대한 침투통의 저감효과를 분석하여 우수유출저감시설로써 적용성과 치수효과를 검증하는데 그 목적이 있으며, 연구방법으로는 실제 호우사상에 대해 침투통의 현장계측을 이용하여 유출 저감율을 측정하고, 수문해석에 의해 저감효과를 분석하였다. 현장계측을 실시한 전주지역의 2005년 8월 2일 호우사상은 290.5mm를 나타냈으며, 이 강우량은 $\ulcorner$한국확률강우량도(한국건설기술연구원, 2000)$\lrcorner$에 의한 전주관측소 50년 빈도 24시간 확률강우량 287.7mm를 초과하는 값으로 분석되었다. 이 때, 총유출저감율은 약 56%로 측정되었으며, 유역특성이 비슷한 지역에서는 해당 강우량에 대해 유사한 저감효과를 나타낼 것으로 판단된다. HEC-HMS와 단위침투설계법을 이용하여 수문해석을 실시하였으며, 동일한 호우사상 자료를 적용한 결과, 총유출저감량은 20.64%, 최대 첨두유량은 6%의 저감율을 나타냈다. 향후 지속적인 모니터링과 첨두유량에 대한 연구가 보완되고 호우사상에 대한 계측자료가 추가로 확보된다면 호우사상에 대한 침투통의 치수효과를 정량화할 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2215-2219
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• 2009

For model calibration in rainfall-runoff modeling, streamflow data at a specific outlet is obviously required but is not sufficient to identify parameters of a model since numerous parameter combinations can result in very similar model performance measures (i.e. objective functions) and indistinguishable simulated hydrographs. This phenomenon has been called 'equifinality' due to inherent parameter uncertainty involved in rainfall-runoff modeling. This study aims to investigate catchment responses in time and space to various uncertain parameter sets in distributed rainfall-runoff modeling. Seven plausible (or behavioral) parameter sets, which guarantee identically-good model performances, were sampled using deterministic and stochastic optimization methods entitled SCE and SCEM, respectively. Then, we applied them to a computational tracer method linked with a distributed rainfall-runoff model in order to trace and visualize potential origins of streamflow at a catchment outlet. The results showed that all hydrograph simulations based on the plausible parameter sets were performed equally well while internal catchment responses to them showed totally different aspects; different parameter values led to different distributions with respect to the streamflow origins in space and time despite identical simulated hydrographs. Additional information provided by the computational tracer method may be utilized as a complementary constraint for filtering out non-physical parameter set(s) (or reducing parameter uncertainty) in distributed rainfall-runoff modeling.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.6
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• pp.713-722
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• 2010

This paper has assessed the flow patterns and settling efficiency in the sedimentation basin using the particle tracking method of the CFD code and has reached the following conclusions: In the original design where no baffle is installed in the sedimentation basin, a large recirculating area where the flow stagnates is created in the right side of the sedimentation basin, with most of the particles moving to the left side of the sedimentation basin following the flow. This biased flow structure in the sedimentation basin reduces the residence time of particles and thereby undermines settling efficiency. The biased flow toward the left side of the sedimentation basin is alleviated by installing a baffle in the sedimentation basin, promptly reducing the fast flow of over 0.7 m/s in the inlet of the sedimentation basin to the rate below 0.2 m/s. In this paper's simulation conditions, if a one-sided baffle is to be installed in the sedimentation basin, placing it 15 meters away from the basin's inlet leads to the best settling efficiency; it has also been analyzed that installing a two-sided baffle-rather than a one-sided one-is a better option in terms of settling efficiency. The highest settling efficiency of 96.2% is achieved when the underwater length of the two-sided baffle is set at 8 meters.

• Environmental Engineering Research
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• v.20 no.3
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• pp.212-222
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• 2015

Experiments were conducted on the immobilization of eight heavy metals (HMs) (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) during 20-day rotary drum composting of water hyacinth. The Tessier sequential extraction procedure was used to investigate the fractionation of HMs. The eco-toxicity risk of HMs was assessed by risk assessment code (RAC). In the results, the bioavailability factor (BAF) for different HMs presented in the following order: Mn > Zn = Fe > Cu > Cr > Cd = Pb > Ni. The total concentration of Pb was higher than that of Zn, Cu, Mn, Cd and Cr; however, its BAF was the lowest among these HMs. These results confirmed that the eco-toxicity of HMs depends on bioavailable fractions rather than on the total concentration. The greatest reduction in bioavailability and eco-toxicity risk of HMs occurred in lime 1% and 2% as compared to control and lime 3%. The eco-toxicity risk of Fe, Ni, Pb, Cd and Cr was reduced from low risk to zero risk by rotary drum composting. These studies demonstrated the high efficiency of the rotary drum for degrading compost materials and for reducing the bioavailability and eco-toxicity risk of HMs during the composting process.

• Journal of the Korean Society of Food Culture
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• v.17 no.2
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• pp.103-110
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• 2002

Mulberry Leaf (Morus-alba) is effective on reducing blood sugar increase and cholesterol in the blood. The objective of this study is to elucidate the sensory and physicochemical attributes of Mulberry Leaf Boogag with different amounts of glutinous rice paste and ginger juice. Mulberry Leaf Boogag, steamed for 90 seconds, was made by puffing the glutinous rice paste and ginger juice. The ratio of glutinous rice paste is made of a double, quintuple, and octuple proportion of water to the weight of the glutinous rice paste. The ratio of ginger juice is at a rate of one, three and five percent. According to the sensory evaluation, hardness and crispiness increased as the glutinous rice paste did, and ginger flavor, bitterness and sourness increased as the ginger juice did. Optimal conditions(p<0.05) were set when the value of hardness was more than five, and the value of bitterness and bitingness, lower than five. The optimal condition of Mulberry Leaf Boogag was established when the ratio of water to glutinous rice paste was 5.5, and in addition, 3.75 percent of ginger juice must be in proportion.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.85-96
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• 2017

In this research, I performed rainfall monitoring by selecting the spot which can represent high altitude cool farm region in recent 3 years, and tried to understand the characteristic of outflow of non-point pollutants coming from high altitude cool farm region. As a result, it was shown that reducing rainfall runoff in highland farm area can reduce non-point pollution load and should consider priority to reduce runoff through management resources when selecting abatement method. Additionally, it is judged that reduction method related to base run-off should be selected by performing research on material motion of TN.

• Environmental Analysis Health and Toxicology
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• v.6 no.1_2
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• pp.7-23
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• 1991

The present study was undertaken to examine the effect of butylhydroxyanisole (BHA) on the lead poisoning in Wister female rats. All experimental rats except normal group were fed with diets formulated by adding BHA in a range of 0.1% to 3.2% and aqueous solution of 1% lead acetate ad libitum through the experimental period. The results obtained are summarized as follows: 1) Lead sedimentation in kidney tissue was decreased with increasing experimental period and BHA level of lead plus BHA-treated groups in comparison with that of lead-treated control group. 2) The weights of lung, spleen and left/right (L/R) kidney were significantly decreased in comparison with those of lead-treated control group after 2 weeks of experimental period, but no difference was shown with those of normal group. 3) The weights of lung, spleen and L/R kidney were increased in lead-treated control group as compared with normal group after 2 weeks of experimental period, but no difference was shown with increasing experimental period. 4) Water intake was remarkably decreased in lead-treated control group as compared with normal group, but water intake by increasing BHA level of lead plus BHA-treated groups showed no significant difference from that of normal group. 5) These results suggest that BHA is effective for reducing the toxic effect of lead in rats.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.43-48
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• 2009

In this study, through case studies, solar energy systems were coordinated with architectural plan elements and the others in apartment complex, and the energy performance was evaluated quantitatively through computer simulation PVSYST and RETScreen. As a results, in plan process of the application of solar energy systems in apartment complex, solar energy system should be considered as not only energy reducing technical element but also part of architectural plan element. And it must be considered with architectural plan elements, composition methods, energy storage methods, technical elements from the early basic plan stage. Photovoltaic system was installed on the wall facing the south and rooftop. The energy ratio of electric load was shown to be 5.5%. The result showed 7.2% when adding it to shading device additionally, and 6.4% in case of putting extra translucent module on windows. Active solar collecting system was applied on roof with the angle of 45. Maximum number of solar collector was 10 in a row, and the total solar collecting area was $915.00m^2$. The energy ratio of domestic water heating load by active solar hot water system is shown to be 11.4%.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.345-351
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• 2008

미래의 기후변화 영향평가에 있어 전지구모형(General Circulation Model)은 가장 중요한 자료 중 하나이다. 즉, 온실가스 방출(emission) 시나리오에 기초한 전지구모형의 모의결과를 이용하면 미래 수자원에 대한 정보를 얻을 수 있다. 하지만 미래 수자원은 방출 시나리오, 상세화(downscaling) 기법, 강우-유출모형, 전지구모형의 종류에 따라 크게 달라질 수 있어 매우 큰 불확실성(uncertainty)을 포함하고 있다. 이러한 불확실성을 줄이는 방법 중 하나로 전지구모형의 모의능력에 따라 가중치(weight)를 부여하고 결합(combining)하는 multi-model 앙상블(ensemble) 기법이 선진국을 중심으로 활발히 연구되고 있다. 본 연구에서는 우선 기후변화 영향평가를 위하여 국내에서 사용가능한 전지구모형을 조사하고 그 중CCSM3, CSRIO, ECHAM4, GFDL, MIRCO를 선택하였다. 한강 충주댐 유역에 대하여 과거($1980{\sim}1999$년)와 미래($2030{\sim}2049$년) 기간에 대하여 전지구모형의 기후정보를 간단한 선형보간법을 이용하여 상세화하였다. 다음으로 multi-model 앙상블 기법을 조사하였다. 본 연구에서는 Giorgi et al.(2002)이 제안한 Reliability Ensemble Average(REA) 기법을 적용하여 선형보간법으로 상세화한 전지구모형의 모의결과에 가중치를 주어 불확실성을 줄이는 연구를 수행하였다. 특히 REA를 구성하는 식 중 모형의 편차(bias) 뿐만 아니라 분산(variance)까지 고려함으로서 이를 개선하는 Modified-REA를 제안하였다. 제안한 방안을 이용하여 결합한 전지구모형의 모의결과가 기존 REA의 결과보다 기후정보의 불확실성을 더 줄일 수 있는 것으로 나타났다.