• 한국측량학회지
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• 제36권1호
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• pp.25-32
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• 2018

Namdae-cheon in Gangwon-do Province, Korea, is a valuable well-preserved lagoon. The estuary of Namdae-cheon Stream is closed because of the surrounding natural sand shoal. Thus, during the dry season, river water cannot easily flow to the ocean and therefore stagnates. River water congestion causes environmental deterioration of estuaries, often by eutrophication. In this study, we examined wall disintegration in the estuary area and used it to determine appropriate measures for the conservation of estuary water quality in the future. A total of 24 sites were selected, with 13 sites on the west side and 11 sites on the east side of the estuary study area. Samples were collected and analyzed for particle size and moisture content both vertically and horizontally. Sedimentary deposition rate was measured, and subsidence analysis was performed. Particle size, water content, sedimentary deposition, and subsidence analyses indicated that flow shifted to the west during the study period. In conjunction with other variables that may affect changes in flow, these parameters can be used in future research to predict shoal breaches and associated changes in water flow direction.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.1438-1441
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• 2008

Throughout the history, the people of Iran have battled the dryness by innovations to preserve every drop of water that lands from the rare clouds, or from a stream flowing out of distant springs. Water is precious and held with highest respect, whether stored for drinking at an Ab-Anbar, or for washing and farming at the Houz in the middle of their oasis homes and orchards, or sourced at a Qanat spring or Jooy under ground. How it is that drinking water as cold as a mountain fall is found in desert of Iran? Ab-Anbar is an ancient means of water preservation and cooling through anunderground building structure. These underground structures have been present in Khorasan and other desert provinces of Iran as public or private water storage facilities, widely used before the installation of public plumbing systems in the late 1950s. Although many of these structures are still functional, most have been protected by government for restoration or viewing by the public as historical heritage. Khorasan natural dry climate and the massive surrounding deserts have been a breeding ground for many designs of Ab-Anbars. Today the existing number of such facilities stands in the province of Khorasan. Usually these structures were built in populated areas, also there are some forms of such structures on old trade routes and roadways leading to and from populated towns. This paper considers the history of Ab-Anbars in Khorasan as well as other relevant aspects such as types, components, construction methods and materials, filling and withdrawal systems.

• 한국환경과학회지
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• 제26권3호
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• pp.401-410
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• 2017

This study analyzed the changes in the concentrations of organic matters in constructed treatment wetlands, coming from discharge water from a sewage treatment plant and non-point pollutant sources during rainfall events. At the beginning of a rainfall event, a massive amount of particulate organic matter flowed in, and was removed from the sedimentation basin (S1, S2); dissolved organic matter was removed after passing through stepwise treatment processes in the wetland. During dry period in the wetland, the removal efficiency rate for COD and TOC was -21 and -7%, respectively; during the rainfall event, the removal efficiency rate for COD and TOC were 47 and 43%, respectively. The highly-concentrated organic matters that flowd in at the beginning of the rainfall event was stabilized by various structures in the wetland before water discharge. Cyanobacteria blooms annually at the confluence of the So-ok stream and Daecheong Lake. Therefore, it is expected that the wetland will contribute significantly to reducing cyanobacteria and improving water quality in the area.

• 생태와환경
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• 제40권4호
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• pp.537-545
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• 2007

The heavy metal removal capacity of filamentous green alga Cladophora sp. cultured together with wet-mixed solidified soil (loess) was tested. A Cladophora sp. was cultured for 5d, with added Chu No. 10 medium, in stream water contaminated by high concentration of heavy metals from a closed mine effluent. Heavy metal ion concentrations of the medium and in algal tissue were measured every day during the experiment. Dissolved metals (Al, Cd, Cu, Fe, Mn, Zn) in medium were rapidly removed (over 90% elimination) within 1-2d when alga and loess were added. Dissolved heavy metals dropped by only 10% when algae were cultured without loess. The Cladophora sp. accumulated much more heavy metals when cultured with loess than when the alga was cultured alone. Cladophora sp. exhibited a maximum uptake capacity for Al ($17,000{\mu}g^{-1}$ algal dry weight). The metal bioremoval capacities of the algae were in the order Al, Fe, Cu, Mn, Zn and Cd. The heavy metal removal capacity of Cladophora sp. showed significant increases when wet-mixed solidified soil was added to culture media.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.151-154
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• 2003

With estmating drinking water demands of Ulsan city, the amount would be increased from 523,000ton/day in 2006 to 635,000 ton/day in 2016. Also, the dependence of Nakdong River on the Ulsan city as a source of drinking water will be very high up to 54.4％ of total drinking water demands. Small-scale drinking water dam is no economical because of excessive construction cost and long construction period. However, development of riverbed and ground water of existing rivers is more economical than that of small-scale drinking water dam. In this study, to utilized Dongchun River as a drinking water resource, Modflow model was used to predict the amount of riverbed and ground water of Dongchun River basin. As a result, available amount of riverbed water was assumed in 6,000 ton/day by worst case (when perfect dry stream) and in case of ground water, it was assumed in 17,800 ton/day.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.407-410
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• 2006

Studies were performed on evaluating the applicability of activated carbon bugs on dye tracer tests as tracer detectors by using its adsorption isotherm of the grained activated carbon. We preliminary conducted several standard adsorption and extraction tests and obtained the relationship between standard dye solution and detected concentrations from activated carbon samples in dry and wet conditions. the slopes of the regression line were 0.71 for wet condition and 0.74 for dried one. Field dye tracer tests were performed in a karst area, where several faults occur along a stream and pass the test area. We sampled water samples and activated carbon samples at three points in Hwangji Pond, where groundwater outflows from the karst conduit. According to the results of breakthrough curve analysis, the regional flow along the conduit, which is assumed to cause a karst conduit, was estimated as 0.18 m/day. The relationship between the concentrations of water sample and extracted activated carbon bugs shows the similar slopes with those from standard solution tests. This suggests that activated carbon could be useful as a dye tracer detector because the extraced concentration can be quantified.

• 대한설비공학회지:설비저널
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• 제3권3호
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• pp.199-208
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• 1974

The effectiveness with which evaporative cooling can be used in Korea was analysed by making use of weather data of 15cities in a past decade. In ASHRAE comfort chart for a still air atmospheric condition was divided into two dimensional array, 14 zones by effective temperature and 10 zones by relative humidity, and all hours of weather condition in those zones were. computed from every 4 hours weather data in a past decade. From this computation obtained were for 15 cities : 1. average annual total hours above $23^{\circ}C$ ET 2. effective temperatures with $5\%$ excess factor, and 3. ratios of all hours in wet (above $25.6^{\circ}C$ WBT), intermediate $(22^{\circ}C\;to\;25.6^{\circ}C\;WBT)$, and dry $(below\;22^{\circ}C\;WBT)$ area to total hours in whole area on comfort chart beyond $23^{\circ}C$ ET to effective temperature of $5\%$ excess factor. It was shown from this computational result that in Korea evaporative cooling was not effective for building and residential comfort air conditioning but could be useful for comfort air conditioning in industry and industrial air conditioning, depending upon the air stream velocity and the type of application.

• 한국환경과학회지
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• 제26권10호
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• pp.1135-1146
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• 2017

At riverbank filtration sites, groundwater levels of alluvial aquifers near rivers are sensitive to variation in river discharge and pumping quantities. In this study, the groundwater level fluctuation, pumping quantity, and streamflow rate at the site of a riverbank filtration plant, which produces drinking water, in the lower Nakdong River basin, South Korea were interrelated. The relationship between drawdown ratio and river discharge was very strong with a correlation coefficient of 0.96, showing a greater drawdown ratio in the wet season than in the dry season. Autocorrelation and cross-correlation were carried out to characterize groundwater level fluctuation. Autoregressive model analysis of groundwater water level fluctuation led to efficient estimation and prediction of pumping for riverbank filtration in relation to river discharge rates, using simple inputs of river discharge and pumping data, without the need for numerical models that require data regarding several aquifer properties and hydrologic parameters.

• 대한기계학회논문집
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• 제13권3호
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• pp.490-499
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• 1989

본 연구에서의 CO$_{2}$ 프로세스는 1차 루프인 원자로에서 유도되는 나트륨 과 2차 루프인 CO$_{2}$ 가스터빈 사이클로 구성하였고, CO$_{2}$ 임계점 부근에서 압축을 행하였다. 또한 최적의 사이클을 결정하기 위해 h-s 선도와 이에 대한 열역 학적, 칼로리로 유도하였다. 그리고 최적화를 위해 출력을 각각 300,600, 1000MWe로 선택하였고, 터빈 입구압은 150-350bar의 범위로 선택하였으며 이들로부터 열효율에 영향을 주는 각 설계변수의 특성을 연구 분석하였다.

• 대한환경공학회지
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• 제31권11호
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• pp.1025-1032
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• 2009

본 연구에서는 세탁소에서 배출되는 휘발성유기화합물을 흡착처리하는 공정의 개발 가능성을 검토하였다. 휘발성 유기화합물을 흡착하는 재료로는 핏치계 활성탄소섬유를 선택하였고, 흡착제의 재생방법으로는 전기변동법을 사용하였다. 용제는 트리클로로에틸렌과 톨루엔을 대상으로 하였으며 활성탄소섬유와 용제의 종류에 따른 파과곡선과 흡착량을 비교 검토하였다. 흡착량을 증대시키기 위하여 다양한 방법으로 활성탄소섬유를 전처리하였다. 또한 흡착이 완료된 활성탄소섬유의 재생에 필요한 온도와 허용전압을 측정하였다. 그 결과 트리클로로에틸렌의 흡착에는 미세 기공이 잘 발달된 활성탄소섬유가 우수한 성능을 나타낸 반면 톨루엔의 경우에는 비표면적이 큰 흡착제가 우수한 성능을 보였다. 활성탄소섬유는 흡착제 무게의 41~54%에 해당하는 트리클로로에틸렌을 흡착하였으며 유입되는 휘발성유기화합물의 농도가 높아지면 완전흡착시간은 급격히 짧아지고 흡착량은 서서히 감소하여 낮은 농도의 휘발성유기화합물을 처리하는 것이 보다 유리한 것으로 나타났다. 활성탄소섬유 표면의 산소작용기를 조절한 결과, 진공열처리를 한 활성탄소섬유의 톨루엔 흡착성능이 가장 우수한 것으로 나타나, 톨루엔의 흡착은 빈자리 탄소(vacant carbon site)가 흡착점이라고 판단된다. 흡착된 용제는 $150^{\circ}C$에서 대부분 탈착되었다.