• 방사성폐기물학회지
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• 제14권4호
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• pp.411-422
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• 2016

최근 국내 원전의 경수로 사용후핵연료 습식 저장시설의 포화시점이 다가옴에 따라 운반 및 저장용기를 이용한 건식저장시스템 개발이 활발하게 수행되고 있다. 일반적으로 사용후핵연료 운반 및 저장용기 설계를 위한 차폐해석 시 장전 가능 연료 중 가장 보수적인 연료를 설계기준연료로 선정하여 해석을 수행한다. 그러나 실제 금속 운반용기에 장전되는 사용후핵연료는 해석평가에 적용된 설계기준연료에 한정되지 않고 다양하기 때문에 초기농축도, 연소도, 최소냉각기간의 특성을 고려한 차폐평가를 통하여 장전가능 여부가 결정된다. 이에 본 연구에서는 금속 겸용용기에 장전 가능한 연료를 대상으로 국내 운반기준을 만족하는 최소냉각기간의 결정을 위한 차폐해석 방법을 기술하였다. 특히 발생량이 많은 초기농축도 3.0~4.5wt%의 사용후핵연료는 차폐해석 구간을 세분화하여 평가하여 연구결과의 활용에 효율성을 높이고자 하였다. 차폐평가를 통해 2008년까지 국내 원전에서 발생한 장전대상연료 중 약 81%의 사용후 핵연료를 금속겸용용기로 운반할 수 있는것으로 평가되었다. 본 연구결과를 통해 금속 겸용용기의 운반조건에 장전 가능한 연료의 특성을 제시함으로써 운반 시 운영절차의 개발을 위한 기술적 근거 수립에 도움이 되고자 한다.

• 한국수산과학회지
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• 제37권2호
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• pp.137-147
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• 2004

Sea surface cooling (SSC) with the passage of typhoons is examined in the East Sea using the Japan Meteorological Agency buoy data $(37^{\circ}45'N,\;134^{\circ}23'E)$ during 1983-2000 and a three-dimensional primitive equation model (the Princeton Ocean Model). Forty typhoons in this period induced the SST decrease ranging from about $-0.5^{\circ}C\;to\;-4.3^{\circ}C.$ Intense SSC $(<-2^{\circ}C)$ occurs with typhoons that passed mainly through the left-hand side of the buoy station. The model is implemented to examine a physical process of SSC with a typical-track typhoon in the northwestern Pacific $(24^{\circ}N\;to\;52^{\circ}N).$ The model well reproduces prominent features in the observation and addresses how it happens; SSC is induced mainly by momentum mixing effect stirred with the typhoon rather than upwelling.

• 설비공학논문집
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• 제11권4호
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• pp.440-447
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• 1999

The frosting characteristics on the vertical parallel plates with three cooling plates were experimentally investigated. The experimental parameters were the cooling plate temperature, the air humidity, the air temperature, the air Reynolds number, and the location. The frosting conditions were limited to air temperatures from 10 to $15^{\circ}C$ , air Reynolds numbers from 1600 to 2270, air humidity ratios from 0.00275 to 0.0037kgw/kga and cooling plate temperatures from -10 to $-20^{\circ}C$. Frost growth and density toward the front of the plate were more thick and dense than toward the rear. Frost growth increased with decreasing plate temperature and increasing humidity. In the conditions of the laminar flow, dew point below $0^{\circ}C$and non-cyclic frosting period, frost thickness increased with increasing air temperature. The reason of increasing frost thickness with increasing air temperature was sublimation-ablimation process. The average growth thickness along the locations showed little dependence on the Reynolds numbers.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1424-1428
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• 2009

The performance of a heat pump using river water as a heat source was compared with that of a conventional air-conditioner for cooling and a boiler system for heating. The heat pump system using river water considered the 1-stage cycle for cooling and the 2-stage cycle for heating. The COPs of the river water source heat pump were $0.5{\sim}1.1$ higher than those of the conventional system in the cooling season. The LCC of the river water source heat pump system was lower 13.5% and 32.4% than that of the conventional system I and II. In addition, when the initial cost ratios of the river water source heat pump system to the conventional system I and II were less than 1.2 and 1.4, respectively, an acceptable payback was found to be less than 5 years.

• Ocean and Polar Research
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• 제24권2호
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• pp.135-146
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• 2002

The upper ocean in the western equatorial Pacific warm pool during TOGA-COARE IMET IOP was simulated using a one-dimensional turbulence closure ocean mixed-layer model, which considered recent observations, such as the remarkable enhancement of turbulent kinetic energy near the ocean surface. The shoaling/deepening of the mixed layer and warming/cooling subsurface water in the model were in reasonable agreement with the observations. There was a significant improvement in simulating the cooling trend of the sea surface temperature under a westerly wind burst with heavy rainfall over previous simulations using bulk mixed-layer models. By contrast the simulated sea surface salinity (SSS) departed significantly from the observed SSS, especially during a westerly burst and the subsequent restratification period, which might be due to 3-D control processes, such as downwelling/upwelling or advection.

• 설비공학논문집
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• 제24권4호
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• pp.289-296
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• 2012

The aim of this study is to investigate the performance of a heating and cooling system with aquifer thermal energy storage(ATES heat pump system) known as one of the underground thermal energy storage application systems. The ATES system was composed of heat pump unit and ATES, which was installed in a factory building located in Anseoung. The system represented very high heating and cooling performance, and showed nearly constant COP at each heating and cooling season due to the stability of EWT. The economic analysis about an ATES system and a conventional system was also executed. The conventional system adopted an air-conditioner in the summer season and a LNG boiler in the winter season. The payback period of the ATES system was estimated by 6.62 years.

• 원예과학기술지
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• 제32권6호
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• pp.753-761
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• 2014

Growth and flowering of Cymbidium 'Red Fire' and 'Yokihi' plants were examined in a greenhouse with cooling systems in summer, and with night interruption (NI) lighting in winter as a forcing culture system. The greenhouse was divided into two sections with separate cooling controls during the summer season. One section was cooled by a mist system (mist), while the other section was cooled by a shade screen (shade). During the winter, the greenhouse was redivided into three sections within each cooling system. Plants were grown with NI either at a low light intensity of $3-7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(LNI) or a high l ight intensity of $120{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$(HNI) u sing h igh-pressure sodium l amps during the 22:00-02:00 HR. The control plants were grown under 9 h short-day condition. NI for 16 weeks and cooling for 9 weeks were employed twice during the 2 years of the experimental period. The air temperature was approximately $2^{\circ}C$ lower in the mist than in the shade and the relative humidity was 80 ${\pm}5%$ in the mist compared to $55{\pm}5%$ in the shade. The daily light integral in the mist section was 48% higher than in the shade section. The time from initial planting to flowering pseudobulb emergence decreased with both LNI and HNI for both cultivars, regardless of the cooling treatments. Under NI conditions, however, between 60% and 1 00% of plants of both cultivars flowered in the mist, whereas no or 20% of 'Red Fire' or 'Yokihi' plants, respectively, flowered in the shade treatment over 2 years. Plants grown under the mist had bigger pseudobulbs than those grown in the shade under both NI treatments. These results show that commercial use of NI in winter and a mist cooling system in summer would decrease crop production time to 2 years and increase profits in Cymbidium forcing culture.

• Asian-Australasian Journal of Animal Sciences
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• 제28권7호
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• pp.966-975
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• 2015

Heat production in ruminants follows a diurnal pattern over the course of a day peaking 3 hours following afternoon feeding and then gradually declining to its lowest point prior to morning feeding. In order to clarify the cooling period most effective in reducing decreases in feed intake and milk production, experiments were carried out based on the diurnal rhythm of heat production and heat dissipation. In experiment 1, the effects of hot environment on milk production were investigated. The animals were kept first in a thermoneutral environment ($20.0^{\circ}C$, 80.0%) for 12 days, they were then transitioned to a hot environment ($32^{\circ}C$, 80.0%) for 13 days before being returned to second thermoneutral environment for a further 12 days. In experiment 2, the effectiveness of daytime cooling or nighttime cooling for improving milk production in hot environment was compared. While ten lactating Japanese Saanen goats (aged 2 years, weighing 41.0 kg) during early lactation were used in experiment 1, ten lactating goats (aged 2 years, weighing 47.5 kg) during mid-lactation were used in experiment 2. The animals were fed 300 g of concentrated feed and excessive amounts of crushed alfalfa hay cubes twice daily. Water was given ad libitum. The animals were milked twice daily. When exposed to a hot environment, milk yield and composition decreased significantly (p<0.05). Milk yield in the hot environment did not change with daytime cooling, but tended to increase with nighttime cooling. Compared to the daytime cooling, milk components percentages in the nighttime cooling were not significantly different but the milk components yields in the nighttime cooling were significantly higher (p<0.05). The results indicate that nighttime cooling is more effective than daytime cooling in the reduction of milk production declines in lactating goats exposed to a hot environment.

• 한국주거학회논문집
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• 제14권3호
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• pp.1-8
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• 2003

It is not sufficient to control the indoor thermal environment using only one or two parameters by itself as human response for the control of indoor thermal environment. So a proper environmental thermal index is required for the control of indoor thermal environment effectively. In this study, the physical environment was measured and analysed and the skin temperature of the subjects and their response were investigated to evaluate the optimum thermal comfort range for cooling season in an apartment house. As a result, the optimal temperature was 26.1$^{\circ}C$ and the temperature ranges which more than 80% responded as satisfactory were 24.1~28.$0^{\circ}C$, respectively. As the OT had most significant interrelation with the PMV, it is desirable to use the OT in evaluating the thermal environment during cooling. Also, the comfort range was concluded between OT 25.5~27.3$^{\circ}C$ by appointing the PMV of -0.5~0.5 as the optimum comfort condition. In addition, the Human responses were compared with calculated PMV, OT and MRT and the relationships are suggested in order to utilize to control indoor thermal environment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2637-2641
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• 2008

The ever increasing demand for power and the shortages encountered during summer calls for the implementation of strategies for power saving in industry. Inlet fogging of gas turbine engines is quite popular due to the ease of installation and the relatively low initial cost compared to other inlet cooling methods. In the present investigation, a detailed analysis is carried out on the basis of coincident wet bulb and dry bulb temperature data of a compressed air plant from April to October, 2007 to determine the evaporative cooling potential for the period. The power gain that can be obtained by employing inlet fogging of the air compressors is analyzed based on the real climatic data at several sites in Korea. An experimental set-up was constructed and tests were carried out with the standard impaction pin nozzle. The experimental results were found to match with the theoretical calculations.