• 한국식품과학회지
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• 제37권3호
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• pp.438-442
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• 2005

전분의 가열, 호화과정에서 ohmic heater를 이용하여 가열속도를 변화시키면서 가열속도가 전분현탁액의 팽윤특성 및 물성에 미치는 영향을 고찰하였다. 3% 옥수수 전분현탁액을 가열속도를 변화시키면서 $90^{\circ}C$까지 가열한 후 냉각시키고 현미경 관찰과 입도분포를 측정한 결과 생옥수수 전분입자의 평균 직경은 $13.7{\mu}m$이었으며 $0.6^{\circ}C/min$의 가열속도로 가열했을 경우 $30.97{\mu}m$, $16.4^{\circ}C/min$로 가열한 경우는 $37.88\;{\mu}m$로 평균직경이 급속히 증가하였으나 $16.4^{\circ}C/min$ 이상의 가열속도에서는 완만히 증가하여 $45.5^{\circ}C/min$일 때는 $41.56\;{\mu}m$로 증가하였다. 즉, 가열속도는 전분입자의 팽윤에 영향을 주며, 가열속도의 증가는 전분입자의 팽윤을 촉진하는 것으로 나타났다. $7.5^{\circ}C/min$ 이하의 낯은 속도로 가열한 3% 옥수수 전분현탁액은 Newtonian fluid에 가까운 유동곡선 특성을 보였다. 그러나 가열속도 $16.4^{\circ}C/min$ 이상에서는 전분현탁액이 pseudoplastic fluid의 거동을 나타내었으며, yield stress가 현저히 증가되었다. 또한 겉보기 점도는 가열속도가 증가함에 따라 선형적으로 증가하였다. 15%의 옥수수전분현탁액을 각각 다른 가열속도로 $90^{\circ}C$까지 가열한 후, 전분겔을 조제하여 가열속도에 따른 전분겔의 견고성(hardness)을 측정한 결과, 완만 가열하여 제조한 전분겔의 견고성은 높은 값을 나타내었으며, 가열속도가 증가함에 따라 차츰 감소하다가 가열속도 $9.4-23.2^{\circ}C/min$의 범위에서는 거의 일정한 값을 나타내었다. 그러나 이후에는 가열속도가 증가함에 따라 전분겔의 견고성이 다시 증가하였다.

• 한국연초학회지
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• 제3권2호
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• pp.89-93
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• 1981

Some or the parameters affecting the thermal analysis of different types of ground tobacco have been discussed. The sample, Korean flue- cured and burley and Greek orient tobacco leaves were run in air at heating rate of $10^{\circ}$ and 20^{\circ}C$ per minute. The thermograms obtained were divided into four temperature zones. The effect of different heating rates on thermal degradation has been discussed At the lower heating rate the maxima of DTA curves in zone 3 and 4 were 25-$40^{\circ}C$ lower than that of the higher heating rate.

• 설비공학논문집
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• 제26권12호
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• pp.572-578
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• 2014

Heating energy was measured in an apartment housing unit with a district heating system, varying the kind of hot water distributors. Ondol coils passing through a living room raised the temperature of the room where the heating was turned off. Including this characteristic of Ondol heating into the modeling, we performed simulations and showed a verification by comparison with the results of measurements. As a result, a main flow control method, which changes hot water flow rate supplied to a housing unit according to the thermal load, can reduce the supplied flow rate and lower the return temperature, compared with a constant flow method. That can result in decreased heat loss in utility-pipe conduits even though the heating energy supplied is almost the same. An outdoor reset control that raises the temperature of the supplied hot water if the outdoor temperature falls has the effect of a quicker response in heating than the reduced flow rate and return temperature.

• 한국군사과학기술학회지
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• 제8권2호
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• pp.77-87
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• 2005

The thermomechanical characteristics were evaluated for 17-4PH stainless steel widely used in supersonic airframe subjected to both aerodynamic loading and heating. The thermomechanical tests were conducted under both elevated temperature and rapid heating condition from $1^{\circ}C/sec\;to\;28^{\circ}C/sec$. The thermomechanical behaviors under rapid heating were compared with those of elevated temperature after 1/2 hour exposure in terms of yield stress to investigate the influence of heating rates. A heating rate-yield temperature parameter was suggested for rapid heating based on time-temperature parameters, and master yield stress curve was obtained by using these parameters. The experimental results and methodology from this study can be used as basic engineering data when designing supersonic vehicle structures subjected to aerodynamic loading and severe heating environment.

• 한국세라믹학회지
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• 제27권8호
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• pp.1020-1026
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• 1990

The effect of heating rate on the microstructural evolution during sintering of PZT ceramics has been investigated. In case of PZT powder compacts containing excess of PbO, fast heating caused incomplete rearrangement of solid grains in a liquid, resulting in lower density and inhomogeneous pore shape ; on contrary, slow heating resulted in better densification. In contrast, in case of compacts without excess PbO, the densification was enhanced by fast heating due to suppression of the grain growth.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.135-139
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• 2008

Development of surface heating technology using hot jet impingement onto mold inner surface for improvement of pattern transcription. This study is focused on how to control the parameters related to hot jet impingement. The mass flow rate, the jet temperature and the duration of the impingement are major parameters. The nozzle design and other geometric configurations also affect the heat transfer to the surface. In terms of heat transfer analysis, the most important number is the heat transfer coefficient, which is influenced by the mass flow rate, nozzle design, distance between the nozzle tip and the surface. In summary, several parametric studies using the developed model are conducted to investigate the effects of mass flow rate, jet temperature and Heating Time in Surface heating technology using hot jet impingement onto mold.

• 한국태양에너지학회 논문집
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• 제33권6호
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• pp.54-61
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• 2013

This is study on the glazing performance of the apartment house to predict energy saving rate when the early design stage by calculating heating load. there are various factors of the window type in apartment building to save energy such as window's U-value, SC or SHGC, window wall ration, frame factor, sunshade coefficient and so on. In this study, we analyzed the heating load focused on the U-value, SC and window wall ration using variable heating degree days method for a small and middle size units $59m^2$, $84m^2$, respectively. Each cases were calculated heating load of the real models compared to standard model to predict energy saving rate. From those cases it was drew the conclusion that were window's U-value, SC and window wall ration for the small and middle size units to expect 10% energy saving rate at least.

• Journal of Welding and Joining
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• 제5권1호
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• pp.73-80
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• 1987

During PWHT, it is well known that residual stress in weld HAZ is one of the reasons for PWHT embitterment. In case of static loading, it was experimentally found that fracture toughness of weld HAZ was dependant upon PWHT conditions. However, the effects of PWHT on fatigue behavior are not clearly verified. Therefore, in this paper, the effects of heating rate PWHT conditions and residual stress simulated in weld HAZ of Cr-Mo steel on fatigue crack propagation behavior were evaluated by fatigue Testing and SEM observation. The obtained results are summarized as follows; 1. Applied stress($10 Kgf/mm^2$) in weld HAZ during PWHT tneded to decrease fatigue strength and to increase fatigue crack growth rate. 2. Applied stress and slow heating rate of 60.deg. C/hr during PWHT contributed to precipitin of impurity elements as well as carbide, which promoted the fatigue crack growth. 3. Fatigue crack growth rate decreased at the heating rate of 220.deg. C/hr in contrast with 600.deg. C/hr and 60.deg. C/hr.

• 설비공학논문집
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• 제9권2호
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• pp.180-188
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• 1997

The theoretical analysis and experiment with simulator were performed to obtain the temperature distributions in radiant heating panel and heat supply from hot water to heating space for the purpose of the development of comfortable living space from a point of view of the improvement of air quality and the enhancement of system efficiency. The relations of various parameters, such as pipe pitch, room temperature as well as flow rate and temperature of hot water and so on, with the rate of heat supplied, mean temperature and maximum temperature difference at panel surface were discussed. The effects of these parameters were also verified on the thermal performance of heating panel using the relations which could be used for the optimal design and operation of the radiant heating panel.

• 임산에너지
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• 제22권1호
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• pp.37-43
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• 2003

천연셀룰로오스의 탄화과정에서 탄화수율에 영향을 미치는 인자는 탄화온도, 승온속도 및 탄화로 내의 분위기를 들 수 있다. 일반적으로 탄화수율을 높이기 위해서는 탄화목표온도를 낮추고, 승온속도를 느리게 하면 탄화로의 분위기를 불활성가스의 조건에서 탄화수율이 높아진다고 보고되어 있다. 본 연구에서는 탄화조건 중에서 가장 유동성을 가지고 있는 승온속도를 조절하고, 탈수촉매제로서 황산을 첨가함으로서 탄화수율의 향상과 탄화과정에서 천연셀룰로오스를 재료로 하여 탄화특성에 대하여 조사하였다. 그 결과 황산무처리시료에 대하여는 승온속도가 증가함에 따라 수율이 상당히 감소하였지만 황산처리 시료는 승온속도가 증가하여도 수율 감소 폭이 크지 않았다. 본 연구의 결과에서 탄화과정에 있어서 승온속도의 조절과 적당한 탈수제의 첨가는 탄화재료의 수율 향상과 탄화시간 단축에 유용한 기초자료가 될 것으로 생각된다.