• 한국해양공학회지
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• 제27권5호
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• pp.77-81
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• 2013

The effects of the welding parameters, contact tip-to-workpiece distance (CTWD), current, and voltage on the diffusible hydrogen content in weld metal deposited by self-shielded flux cored arc welding were investigated and rationalized by comparing the amount of heat generated in the extension length of the wire. This showed that as CTWD increased from 15mm to 25mm, the amount of heat generated was increased from 71.1J to 174.8J, and the hydrogen content was decreased from 11.3mL/100g to 5.9mL/100 g. Even if little difference was observed in the amount of heat generated, the hydrogen content was increased with an increase in voltage because of the longer arc length. A regression analysis showed that the regression coefficient of voltage in self-shielded flux cored arc welding is greater than that in $CO_2$ arc welding. This implies that voltage control is more important in self-shielded flux cored arc welding than in $CO_2$ arc welding.

• 한국초등과학교육학회지:초등과학교육
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• 제21권1호
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• pp.81-100
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• 2002

This study identified concepts of heat and temperature. The study was conducted by 200 pre-service elementary school teachers at J-university. The questionnaire consisted of 11 multiple choice questions regarding equilibrium of heat, amount of heat, conduction, and radiation. The questions were designed to provide reasons based on answers. The results showed a misconception about the direction of heat transfer. A large percentage of individuals surveyed believed temperature was a measure of heat and also thought heat to be an element. They were not able to distinguish between conceptions of heat and conceptions of temperature.

• 설비공학논문집
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• 제16권3호
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• pp.273-279
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• 2004

A lab-scale fluidized bed heat exchanger for waste gas heat recovery is devised and tested. Compared to our previous works on fluidized bed type system with a single riser, the present heat exchanger system is featured by its multiple (four) risers to handle increased amount of exhaust gas. Particles are introduced to the main hot gas stream alongside the pipe circumference near riser inlets. The heat exchanger performance and pressure drop are evaluated through experiments for the present gas-to-water heat exchanger system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.87.2-87.2
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• 2010

The steady and dynamic process model for an internal reforming molten carbonate fuel cell power plant is discussed in this paper. The dominant thermal and chemical dynamic processes are modeled for the stack module and balance-of-plant, including cathode gas preparation, heat recovery, heat loss (Each heat loss amount for the stack and MBOP is obtained from real plant data) and fuel processing. Based on dynamic model and control demand, PID controllers are designed in the whole system. By applying these controllers we can obtain temperature balance of stack and control system depending on changing steam to carbon ratio, air feed amount, and transient condition.

• 연구논문집
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• 통권25호
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• pp.155-161
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• 1995

During casting of A390 billet by Hot Top process, bosses were formed on the surface of cast bar. The formation of boss is assumed due to a large amount of latent heat released during the formation of primary Si in A390 alloy. The low melting point elements around primary Si are locally remelted to liquid and interdendrite offers a path by which the liquid can pass through to the surface. Addition of Sr decreases the amount of latent heat by preventing the formation of primary Si near the surface and thus suppresses the formation of boss on the surface of cast bar. Therefore, the formation of boss could be reduced remarkably when the casting condition was selected to extract the latent heat outward easily.

• 동력기계공학회지
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• 제4권1호
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• pp.74-80
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• 2000

This present study was investigated effect of Ni contents on the high temperature strength characteristic in 9Cr ferritic heat-resistant steel added 1.7%W in place of Mo in order to restraint laves phase formation. Precipitation amount of carbide, number of particle per unit area and particle size of carbide were decreased with increase of Ni content. In the steels, carbides of $M_{23}C_6$ type was mainly precipitated, but laves phases could not precipitated. Tensile and yield strength, creep strength and creep rupture time was decreased, but elongation were increased due to decreasing of particle number per unite area and carbide amount precipitated with increase of Ni content.

• 한국식품영양과학회지
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• 제21권1호
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• pp.49-53
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• 1992

십자화과 채소를 습열처리한 thiocyanate ion의 방출량은 열처리시간이 증가함에 따라 점차 증가하여 30분 열처리시 최대치를 나타내었으나, 건열처리시는 유의적인 변화가 없었다. 또한, 내생의 효소 myrosinase에 의한 자가분해시는 방치시간이 경과함에 따라 점차 증가하여 3시간 후에 최대치를 나타내었는데, 이는 습열처리시의 최대 방출량보다 많은 양을 나타내었으며, 시료별 방출량은 양배추, 배추, 무, 케일 및 겨자의 순으로 높게 나타났다. 열처리에 따른 indoleacetonitrile의 생성량은 시간이 경과함에 따라 증가함을 나타내었으며, 시료별 생성량은 양배추 및 무 순으로 높게 나타났다.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2003년도 International Symposium on Clean Environment
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• pp.165-170
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• 2003

A significant surface net heat loss appears around the Kuroshio and the Tsushima Warm Current regions. The area where the surface heat loss occurs should require heat to be supplied by the current to maintain the long-term annual heat balance. Oceanic heat advection in these regions plays an important role in the heat budget. The spatial distribution of the heat supply by the Tsushima Warm Current near the surface was examined by calculating the horizontal heat supply in the surface layer of the East/Japan Sea, directly from historical sea surface temperature and current data. We have also found a simple estimation of the effective vertical scale of heat supply by the current to compensate net heat loss using the heat supplied by the current in the surface 10m layer. The heat supplied by the current for the annual heat balance was large in the Korea/Tsushima Strait and along the Japanese Coast, and was small in the northwestern part of the East/Japan Sea. The amount of heat supplied by the current was large in the northwestern part and small in the southeastern part of the East/Japan Sea. These features suggest that the heat supplied by the Tsushima Warm Current is restricted to near the surface around the northeastern part and extends to a deeper layer around the southeastern part of the East/Japan Sea.

• Journal of Advanced Marine Engineering and Technology
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• 제28권4호
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• pp.618-623
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• 2004

This paper has dealt with the heat storage characteristics of gel type micro size latent heat storage material slurry. The heat release operation to the gel type micro size latent heat storage material slurry was carried out using hot air bubbles by direct contact heat exchange. This experiment was carried out using phase change material of n-paraffin so the heat release amount is higher than cold water system. The parameters of this experiment were concentration of latent heat phase change material, height of heat release bath and inlet velocity of hot air. The main results obtained are as follows : (1) The effect of concentration of latent heat phase change material dispersed with water is very affective to the direct contact heat exchange between hot air and gel type micro size latent heat storage material slurry. (2) It is clarified that the most effective concentration of latent heat phase change material dispersed with water exists around 20mass% at this type of direct heat exchange model experiment.

• 한국건축시공학회지
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• 제13권3호
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• pp.218-226
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• 2013

건설재료 중 시멘트 및 철강은 대표적으로 탄산가스를 발생시키는 재료산업이다. 건설 산업에서의 탄소 배출량 감소를 위해서는 이러한 재료의 사용을 감소시키는 것이 가장 효과적이라고 할 수 있다. 본 연구에서는 시멘트의 사용량을 감소시킨 저발열형 혼합시멘트의 개발을 목적으로 하고 있다. 시멘트 혼합 비율을 10 %로 낮춘 저탄소 배출형 저발열 혼합시멘트의 수화 특성 및 콘크리트의 온도상승 특성을 검토하였다. 시험 결과, 혼화재의 반응 활성화를 위해서는 CaO 및 $SO_3$의 공급원 필요하며, 석고 및 생석회를 적정 배합비율 적용할 경우 초기에는 강도 발현이 다소 지연되지만 장기재령에서는 기존의 저발열 혼합시멘트와 유사한 성능을 확보 가능한 것으로 나타났다. 특히 저탄소 저발열 혼합시멘트의 경우 콘크리트의 수화열도 기존 저발열 혼합시멘트에 비해 감소시킬 수 있는 것으로 나타났다.