• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.65-70
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• 2008

The numerical simulation on the internal flow characteristics of the adaptor in a two-fluid nozzle has been performed to investigate the effects of carrier air supplying parameters using a commercial code. The four adaptor models with the different positions in the carrier air supplying port were considered at the fixed conditions of urea-water solution and carrier air supplying. As the results from the numerical analysis, the internal pressure of the adaptor was varied with the port position for carrier air supplying, and it shows lower pressure value than the atmospheric pressure. Consequently, the flowrate of urea-water solution issuing from the feeding injector with the adaptor varied up to 30% with the port positions for the carrier air supplying. When the carrier air is supplied from the side from the feeding injector axis and the upper part from the feeding injector tip, the flowrate of urea-water solution issuing from the feeding injector with the adaptor show higher value than other carrier air supplying conditions.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2003년도 학술발표논문집
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• pp.243-246
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• 2003

The connection channel for Saemangeum district is to link the lakes between Keumkang Lake and Saemangeum Lake and to dilute the polluted water flowing from Mankyung river, to accelerate desalinization in Saemangeum lake, and to satisfy the future demand of water around Saemangeum district. Therefore, this study is to investigate the surplus water in Keumgang Lake after supplying the current agricutural, life, and industrial water and to check the possibility to divert the surplus water to Saemangeum Lake

• 한국농공학회지
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• 제42권2호
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• pp.55-62
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• 2000

In order to make the reasonable irrigation plan in the unripended tidal reclaimed paddy fields, the estimation of irrigation water requirements by soil textures and water management methods for the normal growth of crops is very important . This study was carried out to determine leaching requirements before cultivating crops. For the purpose of this study, the physical and chemical properties of soil samples used in the desalinization experiments were analyzed, and change of salinity by supplying water and leaching water were investigated in the experimental field with lysimeters. As a result considering the soil textures, desalinization effects of good drainage soils(S1) were better than those of poor drainage soils (S2). In the changes of salinity of the soils with supplying water by water management methods, among the good grainage soils with culvert treatment(S1CW), salinity of S1CW3 with 1, 120mm and S1W4 with 1, 440mm supplying water were 2.6dS/m and 1.1dS/m respectively, and salinity of S1NW4 with 1.680mm among those non-culvert treatment (S1NW) was 3.0dS/m, less than critical salanity value 3.0dS/m. On the other hand, of the poor drainage soils with cultvert treatment , salinity of S2CW3 was ranged 9.4-6.0dS/m with supplied water, and that of non-culverted treatment S2NW as 12.3-8.4dS/m.

• 한국조경학회지
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• 제31권6호
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• pp.64-72
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• 2004

This study analyses influences on partial work rates under whole work rates on landscape constructions in Ulsan Grand Park. The schedule management is one of the factors that are very important to the process management of landscape construction. The time process of the whole construction is supposed to be affected by several kinds of work that organize the whole construction. First, this study divides the construction of Ulsan Grand Park into 10 kinds of works: earth work, rain and sanitary sewage water work, water-supplying work, planting work, paving work, water proofing work, fountain work, instituting work and temporary work. Then the time-process curves of all kinds of work are statistically compared to that of the whole construction. The trial methods of statistics are lineal regression, non-lineal regression, and principal analysis. In the result of the non-lineal regression, the rain and sanitary sewage water work, the water-supplying work and the earth work strongly affected the whole construction. The principal analysis results show that the whole construction is affected strongly by the water-supplying work, the rain and sanitary sewage water work and the earth work. However the lineal regression is shown to be senseless because of its high collinearity.

• 한국유체기계학회 논문집
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• 제11권5호
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• pp.50-56
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• 2008

Metal cutting operations involve generation of heat due to friction between the tool and the pieces. This heat needs to be carried away otherwise it creates white spots. To reduce this abnormal heat cutting fluid is used. Cutting fluid also has an important role in the lubrication of the cutting edges of machine tools and the pieces they are shaping, and in sluicing away the resulting swarf. As a cutting fluid, water is a great conductor of heat but is not stable at high temperatures, so to improve stability an emulsion type mixed fluid with water and oil is often used. It is pumped over the cutting site of cutting machines as a state of atomized water droplet coated with oil by using jet. In this paper, to develop cutting fluid supplying nozzle to obtain ultra thin oil film for coating water droplet, a numerical analysis of three dimensional mixed fluid Jet through multi-stage nozzle was carried out by using a finite volume method. Jet flow characteristics such as nozzle exit velocity, development of mixing region, re-entrance and jet intensity were analyzed. Detailed mixing process of fluids such as air, water and oil in the nozzle were also investigated. It is easy to understand complex flow pattern in multi-stage nozzle. Important flow Information for advance design of cutting fluid supplying nozzle was drawn.

• 물과 미래
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• 제16권2호
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• pp.111-122
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• 1983

오늘날 인구증가와 공업화, 도시화 및 수질오염등에 따라 용수수요가 급격히 증가하게 되었다. 본 연구에서는 목표연도인 2001년까지 5개권역에 대한 용수 수요량과 가용수자원량을 비교분석하여 적용확보 방안을 제시하였다. 본 연구를 통하여 얻어진 결과는 아래와 같다. 1) 월별 용수증가추세에 대응하여 지표수와 지하수로 공급함을 원칙으로 하되, 부족량에 대해서는 댐 공급량으로써 보충키로 한다. 또한 소요공급량은 공급에 앞서 완전 확보토록 하여야 한다. 2) 각 권역에서 월별 계절별 최대물부족량은 6월과 하계에 발생한다. 3) 물부족량이 댐 공급량을 초과하게 될 시기는 III권역에서 1984∼1990년 및 1994∼2001년이다. 4) III권역의 물부족량을 확보하기 위하여 영산강 유역의 마산 금호만하구언 완공년도를 2001년에서 1991년으로 앞당겨야 할 것이며, 섬진강 유역에서는 주암댐의 완공년도를 1991년에서 1986년으로 앞당기고 1986년까지는 유역변경에 의하여 섬진강 유역에서 물을 공급 받으면서 지하수 및 소규모 저수지 개발을 행하여야 할 것이다.

• 한국환경복원기술학회지
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• 제16권5호
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• pp.1-17
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• 2013

We researched the fauna restoration of 5 urban streams in Ulsan established as ecological streams by improving water quality and river environment. The fauna inhabitation were compared according to the conditions of geometrical feature such as river width, low-water channel width, ect and water quality, water volumn, inland and forceland. The Mugeo cheon has clearly shown the fauna restoration effects resulting from supplying sustainable maintenance water and wastewater treatments. In the Yaksa cheon, on the other hand, the restoration effects were low due to the inflow of wastewater and sledges in some part of stream ever though the improvement of water quality. The Yeocheon cheon was found to have disadvantage on the ecological inhabitations due to supplying the maintenance water with highly concentrated salinity. The fauna restoration effect of the Meongjeong cheon was low due to the inflow of wastewater to the down stream. Therefore by supplying the maintenance water and improving the connection to the Taehwa river at the estuary, better restoration effects could be observed. In the Cheokgwa cheon, which is almost a natural river, the ecological integrity of the fauna population has been maintained quite well. It was concluded that the project to transform urban streams into ecological streams should focus on not only keeping water volume and quality but also maintaining favorable conditions for the migration and settlement of animal species close to the natural state.

• 비파괴검사학회지
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• 제23권1호
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• pp.1-6
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• 2003

배관 내의 스케일은 통수비를 감소시키므로 배관을 적절히 관리하기 위해서는 스케일량에 대한 정량적인 평가가 필수적이다. 상수도 급수관내의 스케일량을 평가하기 위해서 유도초음파를 사용하였다. 가변각 ??지를 사용하여 유도 초음파의 여러 모드를 발생시키고, 노후 배관을 따라서 전파하는 특성을 분석하였다. 실험적으로 관내의 스케일이 증가함에 따라서 $f{\times}d=1.5MHz\;mm$인 경우에 F(M,2) 모드들의 진폭이 크게 감소하는 것을 알 수 있었다. 본 연구의 결과로 상수도 급수관의 스케일량 평가에 적합한 유도 초음파는 F(M,2) 모드들임을 알 수 있었다.

• 한국환경과학회지
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• 제29권11호
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• pp.1099-1108
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• 2020

In this study, the capacity of supplying agricultural water to 13 districts was analyzed by calculating the necessary water supply for the arable land of Gunwi-gun and examining the capacity of supplying water to reservoirs, streams, pumping stations, collection sites, and groundwater wells in Gunwi-gun. As a result, among the 13 districts the second district was found to be short of water by 1.2×10⁶ tons/year. In general, local governments establish drought measures by selecting drought disaster risk zones. While selecting drought-risk areas, some water-poor areas that do not have water sources should be selected, even if the entire area has a sufficient water supply. The water-supply evaluation at the regional level was insufficient for locating areas without water sources, but most areas with water sources, such as streams, reservoirs, and pumping stations, were found to have no shortage of water. To locate water shortage areas without water sources, GIS analysis conducted a field survey of areas with a distance of 4 or less than that of water sources analyzed by GIS analysis. Sixty-nine sites in 13 districts were selected for the on-site survey and six areas of water shortage were identified in areas other than the second district.

• 한국습지학회지
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• 제15권3호
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• pp.317-328
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• 2013

울산시의 대표적인 5개 도시하천인 무거천, 약사천 여천천, 명정천 및 척과천 등 5개 하천을 대상으로 유지용수 공급방법과 그에 따른 생태복원 정도를 조사하여 비교 검토하였다. 유지용수의 지속적인 공급으로 하천의 수질을 획기적으로 개선시킬 수 있었고 생태계가 점진적으로 복원되는 것을 확인할 수 있었다. 하지만 염도가 높거나 수질이 좋지 못한 유지 용수는 비록 많은 양을 공급하더라도 생태계 복원에 도움이 되지 못하거나 오히려 악영향을 미칠 수 있는 것으로 확인되었다. 하폭이 좁은 도시하천을 생태하천으로 조성하거나 유지하기 위해서는 산책로 조성 등 시설물 설치는 최소화해야 하고, 적절한 유지용수 확보와 본류 하천과의 연결성이 가장 중요한 것으로 판단되었다.