• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.507-510
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• 2003

The development of a basin-wide runoff analysis model is to analysis monthly and daily hydrologic runoff components including surface runoff, subsurface runoff, return flow, etc. at key operation station in the targeted basin. A short-term water demand forecasting technology will be developed taking into account the patterns of municipal, industrial and agricultural water uses. For the development and utilization of runoff analysis model, relevant basin information including historical precipitation and river water stage data, geophysical basin characteristics, and water intake and consumptions needs to be collected and stored into the hydrologic database of Integrated Real-time Water Information System. The well-known SSARR model was selected for the basis of continuous daily runoff model for forecasting short and long-term natural flows.

• 한국환경과학회지
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• 제7권2호
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• pp.171-176
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• 1998

This study was conducted to evaluate water quality utilizing principal component analysis in the Nakdong River Estuary. From the results of analysis, water quality in the Nakdong River Estuary could be explained up to 65.3 Percente by three factors which were Included In river loadlnwastes from the Nakdong River and rainfalls : 39.1%1, sediment resuspension(13.7BS) and metabolism(12.5%). In the eastern part of estuary In flowing the Nakdong River, river loading factor score(factor 1 Pas higher than that In western part. Sediment resuspension factor score(factor 2) was high in shallow water, while metabolism factor score(factor 3) was high in deeper water. For seasonal variations of factors score, factor 1 was h19h- 1y related to rainfall season.

• KEPCO Journal on Electric Power and Energy
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• 제7권1호
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• pp.125-128
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• 2021

This paper presents the root cause failure analysis of the circulating water pump in the 560 MW thermal power plant. A fractured austenitic stainless-steel shaft operated for 24 years was examined. Fracture morphology was investigated by micro and macro-fractographic analysis. The metallurgical analyses including chemical analysis, metallography and hardness testing were performed. The analysis reveals that the pump shaft was fractured due to the reverse bending load with combination of rotating bending load. Corrective actions for plant operator was recommended based on the analysis.

• 대한환경공학회지
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• 제33권11호
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• pp.797-803
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• 2011

본 연구에서는 물 사용관련 주요 지표인 1인1일 급수량을 이용하여 수요관리 추진 결과 분석 및 절감량을 산정하고, 수요관리를 통하여 발생하는 절감량을 물 수급전망에 연계할 수 있는 시스템을 개발하였다. 1인1일 급수량 분석결과 상수도 여건이 열악한 지자체는 상수도 보급 개선이 선행되어야 하며, 장래용수수요량 추정시에도 이를 고려하여야 할 것으로 판단된다. 금강권역을 대상으로 수요관리 절감량을 산정하고 K-WEAP (Korea-Water Evaluation And Planning System)을 이용하여 물수지분석을 수행한 결과 하천유량 변화 및 지하수와 저수지저수량 증가를 확인하였으며, 이는 다른 용도로 활용 가능하다고 판단된다.

• 대한의생명과학회지
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• 제9권3호
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• pp.139-144
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• 2003

Since water borne infection causes acute diseases and results in spread of diseases by secondary infection, the prevention is very important. Therefore, it is necessary to have a method that is rapid and effective to monitor pathogenic bacteria in drinking water. In this study, we employed a systematic method, Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) analysis, to develop an effective monitoring system for possible bacterial contaminants in drinking water. For this purpose, PCR primers were derived from 992 bp region of the 16s rRNA gene that is highly conserved through the different species of prokaryotes. To test whether the PCR primers designed are indeed useful for detecting all the possible microbial contaminants in the water, the primers were used to amplify 16s rRNA regions of different microbial water-borne pathogens such as E. coli, Salmonella, Yersinia, Listeria, and Staphylococcus. As expected, all of tested microorganisms amplified expected size of PCR products indicating designed PCR primers for 16s rRNA indeed can be useful to amplify all different microbial water-borne pathogens in the water. Furthermore, to test whether these 16s rRNA based PCR primers can detect bacterial populations present in the water, water samples taken from diverse sources, such as river, tap, and sewage, were used for amplification. PCR products were for then subjected for cloning into a T-vector to generate a library containing 16s rRNA sequences from various bacteria. With cloned PCR products, RFLP analysis was done using PCR products digested with restriction enzyme such as Hae III to obtain species-specific RFLP profiles. After PCR-RFLP, the bacterial clones which showed the same RFLP profiles were regarded as the same ones, and the clones which showed distinctive RFLP profiles were subsequently subjected for sequence analysis for species identification. By this PCR-RFLP analysis, we were able to reveal diverse populations of bacteria living in water. In brief, in unsterilized natural river water, over 60 different species of bacteria were found. On the other hand, no PCR products were detected in drinking tap-water. The results from this study clearly indicate that the PCR-RFLP-sequence analysis can be a useful method for monitoring diverse, perhaps pathogenic bacteria contaminated in water in a rapid fashion.

• 한국농공학회논문집
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• 제57권3호
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• pp.121-127
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• 2015

The objective of this study is to suggest the water quality criteria of total nitrogen in order to efficiently manage the nutrient pollution in the stream. For this, correlations between water quality parameters were examined using the water quality data collected from the water quality monitoring network in the four rivers between 2003 and 2012. T-N showed positive correlations with T-P (0.636), COD (0.577), BOD (0.574), TOC (0.440), and SS (0.367). The statistical analysis including percentile analysis for the T-N and T-P concentrations was utilized to develop the water quality criteria of T-N. The feasibility of the suggested water quality criteria was evaluated by calculating the achievement rate to water quality target at the representative points in mid-watershed, then the draft water quality standard of T-N was suggested. The suggested water quality standard of T-N in the stream may be used to efficiently control the nutrient pollution in the public water body.

• Fisheries and Aquatic Sciences
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• 제3권2호
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• pp.143-150
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• 2000

Assuming that summer surface waters in the South Sea (northern East China Sea) are formed mostly by a mixing of three source water (Changjiang Discharge Water; Kuroshio Water and Yellow Sea Surface Water) we apply optimum multiparameter (OMP) analysis to calculate the mixing ratio of each source water to a given surface water. Since OMP requires more parameters than the number of water types (three in this study), we utilize two radium isotopes of dissolved $^{226}Ra\;and\;^{228}Ra$ along with temperature and salinity. Parameter values of each source water are deduced from in situ and historical data. Results with three source of waters on the surface waters are quite promising with less than $1\%$ of unanswered portions. Results not only reproduce the measured temperature and salinity faithfully but also discern the water masses of similar T and S according to their source water mixing. Extending OMP analysis to a whole water column obviously requires more parameters because more source waters are involved in the water mass formation. Original OMP routine utilized dissolved oxygen and nutrients. However, they seem to be perturbed too much by biological activities in the case of shallow waters. We discussed the use of other potential parameters. Also the benefit of parameter substitution is briefly introduced for the future OMP application on shallow waters.

• 상하수도학회지
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• 제18권5호
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• pp.628-637
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• 2004

In many drinking water treatment plants, chlorination process is one of the main techniques used for the disinfection of water. This disinfecting treatment leads to the formation of disinfection by-products (DBPs) such as haloacetonitriles (HANs), trihalomethanes (THMs), haloacetic acids (HAAs). In this study, headspace-solid phase microextraction (HS- SPME) technique was applied for the analysis of HANs in drinking water. The effects of experimental parameters such as selection of SPME fiber, the addition of salts, magnetic stirring, extraction temperature, extraction time and desorption time on the analysis were investigated. Analytical parameters such as linearity, repeatability and detection limits were also evaluated. The $50/30{\mu}m$-divinylbenzene/carboxen/polydimethylsiloxane fiber, extraction time of 30 minutes, extraction temperature of $20^{\circ}C$ and desorption time of 1 minute at $260^{\circ}C$ were the optimal experimental conditions for the analysis of HANs. The correlation coefficients ($r^2$) for HANs was 0.9979~0.9991, respectively. The relative standard deviations (%RSD) for HANs was 2.3~7.6%, respectively. Detection limits (LDs) for HANs was $0.01{\sim}0.5{\mu}g/L$, respectively.

• 한국터널지하공간학회 논문집
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• 제6권1호
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• pp.41-50
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• 2004

본 논문에서는 기존댐 인접지에 터널구조물을 건설하기 위한 발파시, 폭괴하중으로 인한 지반진통이 댐 제체와 간극수암에 마치는 영향을 고찰하였다. 댐의 안정성 검토는 발파시 발생하는 코어부의 최대입자속도 (Peak Particle Velocity)를 계산하여 수행하였다. 간극수와 지반진동간의 상호 연계해석을 위하여 댐 제체에 대한 정상상태 흐름해석을 수행하여 간극수압 분포를 파악하고, 유발된 과잉간극수암 및 유효응력분포로 발파하중이 인접지반에 미치는 영향을 분석하였다. 또한 발파와 같은 급속하중 재하 후 과잉간극수압의 증가 및 소산현상 해석을 위하여 Finn & Byrne Model을 적용하여 하중재하 전후의 유효응력 변화양상을 검토하였다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제5권2호
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• pp.261-272
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• 2005

In evaluation of electronic reliability on the PCB(Printed Circuit Board), electrochemical migration is one of main test objects. The phenomenon of electrochemical migration occurs In the environment of the high humidity and the high temperature under bias through a continuous aqueous electrolyte. In this paper, the generating mechanism of electrochemical migration is investigated by using water droll acceleration test under various waters. The waters used in the water drop test are city water, distilled water and ionic water. It found that the generated velocity of electrochemical migration depended on the temperature of water and the electrolyte quantity which included in the various waters.