• 한국농공학회논문집
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• 제62권2호
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• pp.111-120
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• 2020

This study assessed the reliability of the agricultural water supply based on future climate change scenarios, and suggested plans to improve the reliability in order to promote the adaptability of irrigation water in agricultural reservoirs to climate change. The assessment of agricultural water supply reliability was performed on reservoirs which had a lower water quantity than their design basis and which had recently been subject to drought. In other words, from the irrigation districts of main intake works among the reservoirs managed by the Korea Rural Community Corporation, 1~2 districts in each province-that is, a total of 13 districts -that were recently designated as a district for securing agricultural water (drought prevention district) were selected. Climate change scenarios were applied to the selected districts to analyze their future water supply reliability compared to the current level. All districts selected showed a drought frequency of 4 years or shorter, which demonstrated the need to establish climate change response plans. As plans for responding to climate change, a plan that utilizes supplemental intake works to reduce the area of the irrigation districts of main intake works, and another one that increases the capacity of main intake works were adopted to reanalyze their water supply reliability. When the area of the irrigation districts of main intake works was reduced by about 30~40%, the drought frequency dropped to more than 10 years, securing the reliability of water supply. To secure the reliability by increasing the capacity of main intake works, it was calculated that about 19,000~2,400,000 tons need to be added to each reservoir. In addition, climate change response plans were suggested to improve the reliability of the water supply in each district based on the results of economic analysis.

• 상하수도학회지
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• 제30권5호
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• pp.491-500
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• 2016

Pressure monitoring is expected to be expanded in a water distribution system according to accelerated development of smart water network management technologies caused by appearances of affordable digital infrastructures like computing, storage and bandwidth. However, the placement of pressure sensors has been determined by engineer's technical decisions since there is no well-defined criteria for deciding a suitable location of pressure sensor. This study presents a placement method of pressure sensors based on the consideration of allowable error in calibrating water network analysis modeling. The proposed method is to find a minimum set of pressure sensors for achieving a reliable management of water transmissions main and increasing the efficiency of their real-time operation. In the case study in Y area's transmission main, the proposed method shows equally distributed pressure sensors in terms of hydraulics. It is expected that the proposed method can be used to manage transmission mains stably and construct a robust real-time network analysis system as a minimal criteria.

• 한국농공학회논문집
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• 제63권3호
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• pp.1-12
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• 2021

Optimal water management is to efficiently and equally supply an appropriate amount of water by using irrigation facilities. Therefore, it is necessary to evaluate water supply capacity through distribution simulation between the designed distribution rate and re-distributed rate according to the changed farming conditions. In this study, we recalculated the agricultural water supply amount of Geumcheon main canal, which beneficiary area was reduced due to the development of Gwangju-Jeonnam innovation city, and we constructed a canal network using the SWMM model to simulate the change in supply rate of each main canal according to the re-distributed rate. Even though the supply amount of the Geumcheon main canal was reduced from 1.20 m³/s to 0.90 m³/s, it showed a similar supply rate to the current, and the reduced quantity could be supplied to the rest of the main canal. As a result, the arrival time at the ends of all main canal, except for the Geumcheon main canal, decreased from 1 to 3 hours, and the supply rate increased from 4 to 17.0% at the main canal located at the end of the beneficiary area of Naju reservoir.

• 한국유체기계학회 논문집
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• 제12권5호
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• pp.7-12
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• 2009

A nuclear fuel test loop(after below, FTL) is installed in the IRI of an irradiation hole in HANARO for testing the neutron irradiation characteristics and thermo hydraulic characteristics of a fuel loaded in a light water power reactor or a heavy water power reactor. There is an in-pile section(IPS) and an out-pile section(OPS) in this test loop. When HANARO is operated normally, the fuel loaded into the IPS has a nuclear reaction heat generated by a neutron irradiation. To remove the generated heat and to maintain the operation conditions of the test fuel, a main cooling water system(MCWS) is installed in the OPS of the FTL. The MCWS is composed of a main cooler, a pressurizer, two circulation pumps, a main heater, an interconnection pipe line and instruments. The interconnection pipeline is a closed loop which is connected to an inlet and an outlet of the IPS respectively. The MCWS is under a cold function test during a start-up period. This paper describes the system flow network analysis results of the flow control of a main cooling water system in the HANARO fuel test loop. It was confirmed through the results that the flow was met the system design requirements.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.45-50
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• 2005

Agricultural water is the main portion of water resources in Korea. And water loss of agricultural water is estimated 6% of all water resources. But studies and data for water loss aren't sufficient. We classified the agricultural water losses and measured the water losses in 6 experimental site. Measurements says that water losses ratio in main canal is 13.8%, water losses for distributing irrigation water is 31.1%. So, the total water losses is about 45%. But the water losses for distributing irrigation water is imperative factor for irrigation, So, it is not right that the water losses for distributing irrigation water is classified water losses and it is necessary to reclassify the agricultural water losses.

• 한국물환경학회지
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• 제24권5호
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• pp.598-602
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• 2008

The Daecheong Reservoir is the largest multi-purpose reservoir in the Keum River basin. This water supply is subject to some of the most serious taste and odor (T&O) problems in the region. The intensity of T&O events increased due to eutrophication during the 1990s. In this study, the temporal occurrence of T&O in raw water from the main Daecheong Reservoir and its regulating reservoir was compared using both an instrumental method (CLSA+GC/MS) and threshold odor number (TON) test from April to December 2006. In addition, biofilms on the submerged macrophytes and rocks were analyzed for two typical T&O causing compounds, Geosmin and 2-MIB. The maximum concentration of Geosmin in the main reservoir was almost two times higher than that in the regulating reservoir. Interestingly, 2-MIB was only detected in water samples from the main reservoir. In the case of T&O causing compounds present in the biofilm on the submerged macrophytes and rocks, the regulating reservoir had lower concentrations compared to those of the main reservoir. It was found that both Geosmin and 2-MIB were detected from the biofilms much earlier than from the water samples. This result suggests that the occurrence of T&O compounds in the biofilms could be used as an early warning indicator of an imminent T&O outbreak in the water body.

• 대한한방내과학회지
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• 제27권1호
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• pp.55-71
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• 2006

Objectives : To find out more pharmacologically efficient way of extraction of herbal dicoction, Gamichungsangbohatang (GMCSBHT). Methods : Several main components of GMCSBHT was compared and analysed between hot water extract of GMCSBHT and Alcohol(70% ethanol) extract of GMCSBHT via HPLC method. Results : Hot water extract of GMCSBHT showed relatively more component content than ethanol extract of GMCSBHT. Also weighted mean of main components of hot water extraction of GMCSBHT was higher than that of alcohol extract of GMCSBHT. But from chromatographic pattern analysis of matching ratio and similarity ratio showed that these two forms of extracts might have different chemical composition, and 3D PDA plot of alcohol extract of GMCSBHT showed high peaks near UV $190{\sim}220nm$ which was invisible in hot water extract of GMCSBHT. Conclusion : Alcohol extract of GMCSBHT may have some special components which do not exist in hot water extract of GMCSBHT.

• 한국물환경학회지
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• 제23권3호
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• pp.356-366
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• 2007

In this paper a methodology is developed to prioritize replacement of water distribution pipes according to the economical efficiency of replacement and assess the long-term effects of water main replacement policies on water distribution systems. The methodology is implemented with MATLAB to develop a computer algorithm which is used to apply the methodology to a case study water distribution system. A pipe break prediction model is used to estimate future costs of pipe repair and replacement, and the economically optimal replacement time of a pipe is estimated by obtaining the time at which the present worth of the total costs of repair and replacement is minimum. The equation for estimating the present worth of the total cost is modified to reflect the fact that a pipe can be replaced in between of failure events. The results of the analyses show that about 9.5% of the pipes in the case study system is required to be replaced within the planning horizon. Analyses of the yearly pipe replacement requirements for the case study system are provided along with the compositions of the replacement. The effects of water main replacement policies, for which yearly replacement length scenario and yearly replacement budget scenario are used, during a planning horizon are simulated in terms of the predicted number of pipe failures and the saved repair costs.

• 에너지공학
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• 제23권4호
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• pp.263-271
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• 2014

터빈 사이클의 성능 상태량을 결정하기 위한 보정 열 성능 분석은 발전소의 향상된 경제성 운전을 위해 요구된다. 본 연구에서는 유용하고 정확한 성능 분석을 위해서 산업 표준인 ASME PTC를 기분으로 하여 성능 데이터를 사용하여 주급수 유량의 영역별 판정 알고리듬을 개발하고 각 영역별 추정 알고리즘을 개발하였다. 추정 알고리즘은 측정 상태량의 상관관계를 기반으로 형상 분류를 제시하고, 이를 기반으로 서포트 벡터 머신 모델링을 이용하여 추정 모델을 구성하였으며, 서포트 벡터 머신 모델링의 우수성을 검증하기 위하여 신경 회로망 모델, 커널 회귀 모델과 비교하였다. 주급수 유량의 형상 분류 및 추정 모델은 터빈 사이클에서 정확한 보정 열 성능 분석을 제공함으로써 향상된 성능 분석에 기여할 것이다.

• 대한화학회지
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• 제13권4호
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• pp.401-407
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• 1969

The results of water analysis for 10 stations in the main Naktong and 11 stations in the tributaries from March to December 1968 are as follows: The water quality of the Naktong River Basin is generally the frist class of water, especially the tributaries, Hwang river, Nam river, Milyang river, Naesongchun, Hoechun, Wichun and Panbyunchun were dissolved in less than 100 mg/l as the amount of the total ion of the main component. In comparison with river discharge, the amount of the total ion of the main component is decreased in June and July, because of the river discharge is increased in those periods. According to the measurement of the conductivity and the hardness, the better water quality is distinguished by the following order: lower part of river (Namji), middle part of river (Waegwan), upper part of river (Yean). The conductivity of Kumho river, Tongchon is higher than the middle part of the main river and Nam river, Chongam is smaller than lower part of the main rivller. The variation of the amount of the total ion of main component in the basin is mainly effected by $HCO_3^-, SO_4^{-2}, Cl^-, Ca^{+2}$. The relationship between $[K^+]\;and\;[C^l-]\;and\;[Na^+]\;and\;[Cl^-]\;are\;[K^+]=0.04\;[Cl^-]+1.7\;mg/l,\;[Na^+]=0.06\;[Cl^-]$ mg/l .The main river was much contaminated by Kumho river and C.O.D. at Gang-chung, Kumho river in June was recorder over the standard about 7 times.