• Membrane and Water Treatment
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• 제10권1호
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• pp.83-89
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• 2019

The most common way of reducing non-point source pollutants from agricultural areas is the installation of reservoirs. However, this method is only effective for surface runoff of settleable pollutants. This study was conducted to estimate the effect of interflow, baseflow, and surface runoff on pollutant runoff in a small agricultural catchment. Runoff of organic matters, SS, and T-P were directly proportional to the rainfall variation, while ammonia and nitrate were inversely proportional to the amount of rainfall. The interflow and baseflow was only 46% of the total stream flow, but the nitrate load reached 78%. The interflow as a nutrient transport pathway should be considered for managing a stream water quality. It requires careful attention and appropriate control methodology such as vegetation to consider the influence by interflow. The reservoir as a dry extended detention pond (DEDP) has function of nutrient captor.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제10권S_2호
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• pp.65-71
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• 2001

The chemical behavior and properties related to the redox state of environmental pollutants were investigated using electrochemical methods. Measurements were taken of variations in the redox potential and cyclic polarization current. The results established the influence of various factors, including concentration, temperature, salt, and pH, on the redox potential and current. These factors were determined to effect the result of the redox reaction. Optimum conditions were also established for each case. It was clearly established that the electrode reaction was from a reversible to an irreversible process, plus it was also mixing reaction current controlled.

• 한국분무공학회지
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• 제1권3호
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• pp.60-66
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• 1996

Finely atomized fuel droplet and good mixed mixture plays very important in improving combustion efficiency in an spark ignition engine. And combustion efficiency has influence directly on the engine power, fuel consumption rate and pollutant emission. In this study, perforated throttle valve which has relatively low value of PR has been developed and studied for the purpose of improving those aims. As a result of this study, it has been verified that the perforated throttle valve makes droplet more finely, and also proved that has a function of contributing to form good mixed mixture, especially in mixture preparation system of carburetor or SPI type spark ignition engine.

• Journal of Advanced Marine Engineering and Technology
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• 제33권4호
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• pp.484-496
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• 2009

The strengthened regulations for atmospheric emissions from ships like MARPOL Annex VI have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. This paper attempts to investigate the configuration of SOFC/GT hybrid power system for LNG tanker taking into account the safety and to analyze the influence of design parameters on the system performance. The simulation results provide the basic data for the design and efficiency improvement of SOFC/GT hybrid system and indicate the guidelines for the safe system operation.

• 대한기계학회논문집
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• 제19권10호
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• pp.2690-2698
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• 1995

Fuel atomization and mixture formation in an gasoline engine has influence on the engine performance and pollutant emission. The throttle valve installed in an intake system plays a greater role in control of mixture quantity in accordance with engine drive condition. In this study, the characteristics of secondary atomization developed at the downstream of the valves were observed using an image processing method. Two major kinds of valves, solid and perforated ones, are chosen in order to compare the valve performance with the experimental parameters of air flow rate, valve opening angle, and valve shapes. For the perforated valve, we can obtain the relatively small sized droplets, and nearly uniformed and dense distributed sprays with low loss coefficient than for the solid valve.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.233-243
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• 2009

The strengthened regulations for atmospheric emissions from ships like MARPOL Annex VI have caused a necessity of new, alternative power system in ships for the low pollutant emissions and the high energy efficiency. This paper attempts to investigate the configuration of SOFC system for LNG tanker taking into account the safety and to analyze the influence of design parameters on the system performance. The simulation results provide the basic data for the design and efficiency improvement of SOFC system and indicate the guidelines for the safe system operation.

• 지적과 국토정보
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• 제51권2호
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• pp.141-150
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• 2021

미세먼지는 사람의 건강에 많은 영향을 미치는 물질로서 이와 관련하여 다양한 연구가 이루어지고 있다. 미세먼지의 인체 영향으로 인해 서울시 모니터링 네트워크에서 측정된 과거 데이터를 활용하여 미세먼지를 예측하려는 다양한 연구가 진행되고 있다. 본 연구는 2019년 5월 서울시의 미세먼지를 중점으로 진행하였으며, 학습에 사용한 변수는 SO₂, CO, NO₂, O₃와 같은 대기오염물질 데이터를 활용하였다. 예측모델은 Adaboost에 기반하여 구축하였고, 훈련모델은 PM₁₀과 PM_2.5로 구분하였다. 에러 메트릭스를 통한 예측모델의 정확도 평가 결과로 Adaboost가 시도되었다. 대기오염물질은 초미세먼지와 더 높은 상관성을 보이는 것으로 나타났지만, 보다 효과적인 분포등급을 제시하기 위해서는 많은 양의 데이터를 학습하고, PM₁₀과 PM_2.5의 공간분포 등급을 효과적으로 예측하기 위해서 교통량 등의 추가적인 변수를 활용할 필요성이 있다고 판단된다.

• 한국분무공학회지
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• 제13권4호
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• pp.200-205
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• 2008

Spray formation mechanism was controlled by a cavitation inside an injection nozzle. Nozzle geometry affects spray characteristics and formation behavior, which could determine engine performance and pollutant formation. A study was carried out on the influence of aspect ratio on cavitation inside a nozzle. The cavitation model available in Star-CD code was used to obtain cavitation behavior inside nozzle, which was compared with previous experimental results. In this paper, a CFD approach combining multiphase Volume-of-Fluid(VOF) and k-model was applied. The numerical results are similar with the experimental results.

• 한국환경과학회지
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• 제12권9호
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• pp.987-996
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• 2003

In this study, we analyzed the relationship between the time-variation trend of air pollution concentration index and the meteorological conditions with CO(carbon monoxide) concentration and meteorological observation data in high-CO episode days. CO is a representative automobile air pollutant. The results are as follows; 1. Most of the high-CO episode days within 30 classes appeared in winter season. 2. Most of them appeared under the surface weather conditions with east-west high-pressure system. The surface winds in this high-pressure area were very light. 3. The high-CO episode days were due to unusual accumulation within urban atmosphere in the morning. 4. The Atmospheric stabilities were more stable, and then the wind-ventilation conditions were worse than yearly mean atmospheric condition in Daegu.

• 한국지리정보학회지
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• 제11권1호
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• pp.45-57
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• 2008

본 연구는 환경지리정보시스템을 활용한 활용하여 수질오염방지시설의 입지 결정요인을 분석하여 적정입지를 선정하는 방안을 제시하고자 한다. 이를 위해 수질오염총량제가 가장 먼저 실시된 낙동강 권역을 대상으로 환경지리정보시스템을 구축한 후 1) 수질오염방지시설의 처리용량에 영향을 미치는 오염원, 2) 수질오염방지시설의 입지와 오염원 배출량간의 관계를 분석하여 향후 어떤 오염방지시설을 어디에 입지시킬 것인가에 대한 정책대안을 제시하였다. 분석결과, 1) 수질오염방지시설의 처리용량 결정에 가장 큰 영향을 주는 오염원은 산업폐수발생량으로 판명되었으며, 2) 수질오염방지시설의 입지에 가장 큰 영향을 미치는 오염원은 산업체의 수로 나타났다. 이에 반해 인구수는 환경시설입지를 제한하는 효과가 있는 것으로 판명되었다. 또한, 경상북도 낙동강 중 상류 유역의 경우 주 오염원인 축산오염원에 대한 대처가 가장 미흡한 것으로 나타나 앞으로 축산오염원의 처리가 가장 시급한 것으로 판단된다. 본 연구는 장차 수질오염방지시설의 입지를 선정하는데 활용될 수 있을 것이며, 각 지역의 오염 특성에 따라 수질오염방지시설을 입지를 결정하는데 크게 기여할 수 있을 것으로 기대된다.