• 제목/요약/키워드: heat variations

검색결과 672건 처리시간 0.028초

위성자료를 이용한 한반도 주변 해상 대기표층의 열속 (Heat Fluxes in the Marine Atmospheric Surface Layer around the Korean Peninsula based on Satellite Data)

  • 홍기만;권병혁;김영섭
    • 수산해양교육연구
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    • 제17권2호
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    • pp.209-217
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    • 2005
  • The energy balance of the surface layer of the water (the Yellow Sea, the East China Sea and the East Sea) was examined using satellite data. Variations of the net heat flux were similar to those of the latent heat flux which was more intensive than the sensible heat flux. The sensible heat flux was affected the difference between the sea surface temperature and the air temperature and was less important over the Yellow Sea. The maximum of the latent heat flux occurred in autumn when the air is drier and the wind is stronger. The shortwave radiation flux decreased with the latitude and depended on the cloudiness as the longwave radiation flux does. Annual variations of heat fluxes show that the latent heat flux was more intensive over the East China Sea than the East Sea and the Yellow Sea, while the spatial differences of the other heat fluxes were weak.

열교환기 용량변화에 따른 하천수열원 열펌프의 성능 변화 (Performance Variations of River Water Source Heat Pump System According to Heat Exchanger Capacity Variations)

  • 박성룡;백영진;김희환;이영수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.1530-1535
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    • 2003
  • The utilization of unused energy is important because it can afford to offer a chance to increase energy efficiency of a heat pump system. One of the promising unused energy sources is river water. It can be used as a heat source in both heating and cooling effectively with its superior features as a secondary working fluids. In this study, the performance of a 5HP heat pump system using river water as a heat source is investigated by both experiment and simulation. According to system simulation results, performance improvement of condenser seems more effective than that of evaporator for better $COP_H$. The serial connection is also preferred among several methods to improve plate type heat exchanger performance. The experimental results show that the hot water of $50{\sim}60^{\circ}C$ can be acquired from water heat source of $5{\sim}9^{\circ}C$ with $COP_H$ of $2.7{\sim}3.5$.

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척추관협착증에 있어서 침과 뜸 자극에 의한 체열 변화의 정량적 해석에 관한 연구 (A Study on the Quantity Analysis to the Heat Variation for the Stenosis of the Lumber by the Acupuncture-Moxa Cautery Stimulations)

  • 조봉관
    • 대한한의진단학회지
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    • 제17권3호
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    • pp.253-262
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    • 2013
  • Objectives This study is on the quantifying method for the acupuncture-moxa cautery heat response index, which are based on the some definitions. Methods The magnitude of the acupuncture-moxa cautery is defined by the pain-feeling of the acupuncture-moxa cautery stimulation: the stimulation magnitude of the acupuncture is 1, that of the direct moxa-cautery is 2, and that of the indirect moxa-cautery is 0.5. The heat variation of the acupuncture-moxa cautery stimulation is defined by the heat variations of the characteristic points pre/post-stimulations in the stenosis of the lumber. The acupuncture-moxa cautery heat response index is defined by the ratio of between the magnitude of the heat variation and the natural logarithmic magnitude of the stimulation. Results With the respect of the acupuncture-moxa cautery heat response index, I experimented and estimated 4 types of stimulations in the stenosis of the lumber: the single acupuncture stimulation with 40%, the single direct moxa-cautery stimulation with 52%, the combinational acupuncture-moxa cautery stimulations with 27%, and the combinational acupuncture-indirect electronic moxa-cautery stimulations with 53%. Conclusions According to the acupuncture-moxa cautery heat response index. the combinational acupuncture-moxa cautery stimulations especially need to be changed to the combinational acupuncture-indirect electronic moxa-cautery stimulations.

TEMPORAL VARIATIONS OF URBAN HEAT ISLAND USING LAND SURFACE TEMPERATURE DERIVED FROM MTSAT-1R

  • Hong, Ki-Ok;Suh, Myoung-Seok;Kang, Jeon-Ho;Kwak, Chong-Heum;Kim, Chan-Soo
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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    • pp.290-293
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    • 2007
  • The land surface temperature (LST) derived from the meteorological satellite can be used to investigate the urban heat island (UHI) and its temporal variations. In this study, we developed LST retrieval algorithm from MTSAT-1R by means of a statistical regression analysis from radiative transfer simulations using MODTRAN 4 for a wide range of atmospheric, satellite viewing angle (SVA) and lapse rate conditions. 535 sets of thermodynamic initial guess retrieval (TIGR) were used for the radiative transfer simulations. Sensitivity and intercomparison results showed that the algorithm, developed in this study, estimated the LST with a similar bias and root mean square errors to that of other algorithms. The magnitude, spatial extent, and seasonal and diurnal variations of the UBI of Korean peninsula were well demonstrated by the LST derived from MTSAT-1R data. In general, the temporal variations of UHI clearly depend on the weather conditions and geographic environment of urban.

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東海海面 熱交換에 影響을 미치는 大氣 및 海洋的 要因 (Atmospheric and Oceanic Factors Affecting the Air-Sea Thermal Interactions in the East Sea (Japan Sea))

  • 강용규
    • 한국해양학회지
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    • 제19권2호
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    • pp.163-171
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    • 1984
  • 대기 및 해양적 요인들이 동해의 해면을 통한 열교환에 미치는 영향을 구명 하기 위하여, 해양의 열수지에 근거한 해석적인 모델을 만들고, 이 모델을 통하여 동해상 해면 열교환의 각 성분과 대기 온도의 연변화를 해석적으로 재현 (simulation) 하였다. 모델에 의한 이론적인 결과에 의하면, 동해에서 난류에 의한 열수송이 클수록 열복사, 잠열 및 현열의 방출이 증가한다. 그리고 표면수온이 증 가 함에 따라 잠열은 증가하지만, 역복사와 현열은 감소한다. 동해에서 연평균 수온이 1$^{\circ}C$ 증가하면 해상 기온의 연평균이 1.2$^{\circ}C$ 증가하는 효과를 가져오며, 해양의 저열량의 크기는 해면을 통한 열교환의 연변화에 지대한 영향을 미친다.

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저열 포틀랜드 시멘트를 사용한 고유동콘크리트의 사용재료 및 배합 변동에 따른 특성 평가 (The Effect on the Properties of High Flowing Concrete Using Low Heat Portland Cement by Material and Mixing Variations)

  • 하재담;김태홍;유재상;이종열;권영호
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.303-308
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    • 2001
  • Recently, concrete structures have become larger and higher and are demanding high performance concrete with lower heat to prevent thermal cracking, far greater workability, high strength and durability, Application of low heat portland(Type IV) cement for the high performance concrete is the best solution to satisfied those requirements. Here are explained the effect on the properties of high flowing concrete using low heat portland cement by material and mixing variations. Variables for sensitivity test were selected items like finess modulus of aggregates, particle size of limestone powder, unit water, superplasticizer, viscosity agent and concrete temperature. The results of this study were be applied to slurry wall of #215 and #216 of underground LNG tank in Inchon.

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개방형 지열히트펌프 시스템의 성능평가 (Performance Evaluation of Open-Loop Ground Water Heat Pump system)

  • 김태원
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 추계학술대회
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    • pp.9-14
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    • 2006
  • Open loop or ground water heat pump systems are the oldest of ground-source systems. Standing column wells can be used as highly efficient ground heat exchanger in geo-thermal heat pump systems, where hydrological and geological conditions are suitable. These systems require some careful considerations for well design, ground water flow, heat exchanger selection etc This paper describes 9round water temperature variations, performances in heat ins and cool ing mode and the results of ground water analysis.

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Sea Level Variations at Kerguelen Island in the South Indian Ocean by the Satellite Data(ARGOS) and Meteorological Data(METEO)

  • Yoon, Hong-Joo
    • 대한원격탐사학회지
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    • 제16권2호
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    • pp.117-133
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    • 2000
  • We studied the sea level variations at Kerguelen island in the South Indian Ocean with ARGOS data and meteorological data during about 1 year(May 1993~April 1994) through using filter, spectral analysis, coherency and phase, and found characteristics for the two oceanic signal levels(detided oceanic signal level, h$_{detided}$ and seasonal oceanic level, h$_{corr.ib}$). The forms of atmospheric pressure variations are good agreed to between ARGOS data and meteorological data in the observed periods. This Kerguelen area shows the inflow of an air temperature(gain of a radiant heat) into the sea water and the stagnation of high atmospheric pressure bands in summer, and the outflow of a sea water temperature(loss of sensible and latent heat) toward the atmosphere and the stagnation of low atmospheric pressure bands in winter. The seasonal difference of sea level between summer and winter is about 1.6cm. Both the detided oceanic signal level(h$_{detided}$) variation and the inverted barometer level(h$_{ib}$) variation have a strong correlation for T>1day period bands. The characteristics of h$_{detided}$ variation are not decided by the influence of any meteorological distributions (atmospheric pressure), but the influence of other factors(bottom water temperature) for T>2days periods bands. h$_{corr.ib}$ plays a very important role of sea level variation in the observed periods (especially T>about 180days period bands).

압축비가 기관의 방열에 미치는 영향 (Effect of compression ratio on the heat dissipation of engine)

  • 이창식
    • 오토저널
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    • 제5권1호
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    • pp.89-93
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    • 1983
  • This paper describes on experimental investigation into the heat dissipation of Diesel engine, placing emphasis on the variations of compression ratio and cooling water temperature. The engine used for this test was a vertical single-cylinder four-cycle type, having a direct injection. Engine performance and heat transfer rates was tested under the compression ratio 14.3 and 17.4. In this study, the results showed that output and transfer rates of engine decrease in accordance with the decrease of compression ratio. The effect of cooling water temperature and injection delay of fuel on the heat dissipation brings about the decrease of heat transfer rates from cylinder to cooling water.

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우유의 열처리가 우유품질과 영양가에 미치는 영향: IV. 우유의 열처리가 우유단백질의 이화학적 성질과 영양에 미치는 영향 (Effects of Heat Treatment on the Nutritional Quality of Milk. IV. Effects of Heat Treatment on the Physical and Nutritional Properties of Milk Protein)

  • 정종욱;정지윤;민태선;오세종
    • Journal of Dairy Science and Biotechnology
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    • 제35권4호
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    • pp.270-285
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    • 2017
  • Among milk proteins, caseins are not subjected to chemical changes during heat treatment of milk; however, whey proteins are partially denatured following heat treatment. The degree of whey protein denaturation by heat treatment is decreased in the order of high temperature short time (HTST) > low temperature long time (LTLT) > direct-ultra-high temperature (UHT) > indirect-UHT. As a result of heat treatment, several changes, including variations in milk nitrogen, interactions between beta-lactoglobulin and k-casein, variations in calcium sulfate and casein micelle size, and delay of milk coagulation by chymosin action, were observed. Lysine, an important essential amino acid found in milk, was partially inactivated during heat treatment. Therefore, the available amount of lysine decreased slightly (1~4% decrease) after heat treatment, However, the influence of heat treatment on the nutritional value of milk was negligible. Nutritional value and nitrogen balance did not differ significantly between UHT and LTLT in milk. In conclusion, our results showed that heat treatment of milk did not alter protein quality. Whey proteins denatured to a limited extent during the heat treatment process, and the nutritional value and protein quality were unaffected by heat treatment.