• 설비공학논문집
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• 제24권2호
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• pp.183-189
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• 2012

Most of the domestic residential buildings have used the traditional radiant heating system, circulating hot water through the cross-linked polyethylene(PE-X) pipe buried in the floor panel of the heating space. New type of the heating panel was recently developed using heat pipes with double wicks. Some experiments were carried out in this study to verify the thermal characteristics of this heating system at the unit heating space which surrounded by outer space whose temperature of air be maintained scheduled value with time. Through the various experiments with several parameters, such as flow rate, inlet and outlet temperatures of hot water and the heating duration and so on, we found that the floor heating system with heat pipes was able to reduce the pumping power for hot water circulation by 4~31% compared with the conventional panel heating system using PE-X pipe. These results could be used for optimal design and efficient operation of the heating system as well as improvement of thermal comfort.

• Journal of Applied Biological Chemistry
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• 제54권3호
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• pp.147-152
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• 2011

고구마 분말을 첨가한 뻥튀기 제조 시 팽화시간, 팽화온도, 수분함량과 같은 팽화조건을 달리하여 물리적 및 관능적 품질 특성을 조사하였다. 실험 결과, 색도에서 수분함량은 유의적 차이를 나타내지 않았지만 팽화온도와 팽화시간이 증가함에 따라 $L^*$값이 감소하고, $a^*$값과 $b^*$값이 증가하였다. 비체적은 팽화시간, 팽화온도, 수분함량이 증가할수록 일반 고구마 뻥튀기의 비체적도 증가하였으며, 파괴력은 낮은 수분함량, 높은 팽화온도, 오랜 팽화시간에서 높게 나타났다. 또한 외관, 색, 향, 조직감, 맛에 대한 패널들의 전체적인 기호도를 나타낸 관능평가에서는 수분함량 및 팽화온도가 높고, 오랜 팽화시간 하에 제조된 시험구가 우수하게 평가되었다.

• 한국가금학회지
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• 제17권2호
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• pp.127-133
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• 1990

가열온도와 시간, pH 및 NaCl 농도가 난백겔의 열안정성에 미치는 영향을 검토하기 위하여 가열처리 후 난백겔의 특성을 검토하였으며 그 결과는 다음과 같다. 난백을 90~$170^{\circ}C$까지 온도와 시간별 가열처리 한 결과. 110~$130^{\circ}C$ 영역에서 경도가 떨어졌으나 온도가 높아짐에 따라서 급격히 증가하였다. 응집성의 경우는 12$0^{\circ}C$까지 감소한 후 $130^{\circ}C$에서 급격히 증가하였다. 명도는 온도가 높아질수록 시간이 길어질수록 낮아졌으며 황색도는 높아졌다. 난백의 경도는 pH 7을 중심으로 산성영역에서는 고온처리가 높았으며 알카리영역에서 밝았다. 고온처리의 경우가 저온처리에 비해 산성영역에서는 보다 밝았으며 알카리 영역에서는 보다 어두웠다. 염의 첨가에 의해 난백의 경도는 저온처리 시에는 큰 변화가 없었으나 고온처리시 다소 증가하였고 응고집성은 저온처리시 서서히 증가하였으며 고온처리시 0.5%까지 급격히 증가하였다. 색택은 고온고리시 명도가 증가하였고 황색도는 감소하였으며 농도별 차이는 크지 않았다.

• 대한한의학회지
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• 제15권2호
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• pp.241-252
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• 1994

It is known that the pattern of combustion temperature can be classified into preheating, heating. retaining and cooling periods. In this experiment. the authors have studied the heating mechanism by the density of moxa material during the heating and retaining periods. The starting point. the point at which it begins to reach the maximum gradient temperature. the ending point of the heating period. and the ending point of the retaining period were measured in order to get effective stmulation by repetition of moxa-combustion. For the experiment. samples of 300mg. 400mg, and 500mg of moxa material were molded into conical molds with each 10mm in diameter and height resulting in the volume of $0.26cm^3$. The following results were obtained: The $300mg/0.26cm^3$ denstiy sample reached al1 points tested faster than the samples of $400mg/0.26cm^3$ and $500mg/0.26cm^3$ It dose not reveal any statistical differences between $400mg/0.26cm^3$ and $500mg/0.26cm^3$ in the ending point. the point at which it begins to reach the maximum gradient temperature of the heating period or the ending point of the reataining period The only difference shown was in the starting point of the heating period. According to the above results. it is concluded that the lower density moxa material reached each point of the the respective period faster than the high density moxa material.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.271-276
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• 2015

Purpose: Quick freezing is widely used in commercial food storage. Well-known freezing techniques such as individual quick freezing require a low-temperature coolant and small cuts for the heat-transfer efficiency. However, the freezing method for bulk food resembles techniques used in the 1970s. In this study, electromagnetic (EM) heating was applied to improve the quick freezing of bulk food. Methods: During freezing, the surface of food can be rapidly cooled by an outside coolant, but the inner parts of the food cool slowly owing to the latent heat from the phase change. EM waves can directly heat the inner parts of food to prevent it from freezing until the outer parts finish their phase change and are cooled rapidly. The center temperature of garlic cloves was probed with optical thermo sensors while liquid nitrogen (LN) was sprayed. Results: When EM heating was applied, the center cooling time of the garlic cloves from freezing until $-10^{\circ}C$ was 48 s, which was approximately half the value of 85 s obtained without EM heating. For the white radish cubes, the center cooling time was also improved, from 288 to 132 s. The samples frozen by LN spray with EM heating had a closer hardness to the unfrozen samples than the samples frozen by LN only. Conclusions: The EM heating during quick freezing functions to maintain the hardness of fresh food by reducing the freezing time from 0 to $-10^{\circ}C$.

• 한국조리학회지
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• 제14권3호
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• pp.210-222
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• 2008

This study showed that the brown stock, which is the base of demi-glace sauce, extracted by using a high pressure heating extractor is more advantageous than that extracted by the traditional extraction method for the mass production. We compared the former with the latter in terms of minerals and free amino acids. The results of this study are summarized as follows. When mineral contents were compared, the brown stock extracted by high.pressure heating extraction showed the tendency of increase in mineral contents in proportion to heating temperature and heating time, but, from extraction temperature of 140$^{\circ}C$, the contents of K, Mg, Na and P decreased with the increase of extraction time. In addition, mineral contents in the brown stock extracted by high-pressure heating extraction were generally lower than those in brown stock extracted by the traditional extraction method. This result was produced probably because materials were added repeatedly in the traditional method. Amino acids contents in brown stock according to the extraction methods were also examined. They increased with the increase in the number of extractions in the brown stock extracted by the traditional method, and those in the brown stock extracted using a high pressure heating extractor increased with the increase in heating temperature and extraction time. The results of this study are expected to be useful as a practical material for the mass production of brown stock products.

• 공업화학
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• 제22권2호
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• pp.214-218
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• 2011

마이크로파 가열 방법과 기존의 가열 방법을 이용하여 석탄회로부터 제올라이트 A를 합성하였다. 반응시간, sodium aluminate의 양, 반응 온도 등이 제올라이트 A의 결정화에 미치는 영향에 대해 연구하였다. $80{\sim}100^{\circ}C$의 범위에서 제올라이트 A의 합성에 필요한 반응 시간은 3~6 h이었으며, 6 h 이상이 되면 결정화도가 오히려 감소하였다. 제올라이트 A의 합성에 필요한 sodium aluminate의 양은 $90^{\circ}C$ 이상에서는 합성용액의 $SiO_2/Al_2O_3$의 비가 0.44~1.05에서 최적이었으며, $80^{\circ}C$에서는 더 많은 양이 필요하였다. 마이크로파 가열 방법은 기존의 가열 방법에 비해 초기 결정화 속도는 약간 증가하였으나, 충분히 결정화되는데 필요한 반응시간은 서로 비슷하였다. 따라서 마이크로파 가열에 의한 석탄회로부터 제올라이트 A의 합성에 미치는 영향은 크지 않다는 것을 알 수 있었다.

• 설비공학논문집
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• 제27권6호
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• pp.283-292
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• 2015

A model of apartment heating load in a district heating system could be useful in the management and utilization of energy resources, since it could predict energy usage and so could assist in the efficient use of energy resources. The heating load in a district heating system varies in a highly nonlinear manner and is subject to many different factors, such as heating area, number of people living in that complex, and ambient temperature. Thus there are few published papers with accurate models of heating load, especially in domestic literature. This work is concerned with the modeling of apartment heating load in a district heating system in winter, using the reduced least square support vector machine (LS-SVM), and with the purpose of using the model to predict heating energy usage in domestic city area. We collected 23,856 pieces of data on heating energy usage over a 12-week period in winter, from 12 heat exchangers in five apartments. Half of the collected data were used to construct the heating load model, and the other half were used to test the model's accuracy. The model was able to predict the heating energy usage pattern rather accurately. It could also estimate the usage of heating energy within of mean absolute percentage error. This implies that the model prediction accuracy needs to be improved further, but it still could be considered as an acceptable model if we consider the nonlinearity and uncertainty of apartment heating energy usage in a district heating system.

• 대한기계학회논문집B
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• 제33권10호
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• pp.820-826
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• 2009

The anisotropic phonon conductions with varying Joule heating rate of the silicon film in Silicon-on-Insulator devices are examined using the electron-phonon interaction model. It is found that the phonon heat transfer rate at each boundary of Si-layer has a strong dependence on the heating power rate. And the phonon flow decreases when the temperature gradient has a sharp change within extremely short length scales such as phonon mean free path. Thus the heat generated in the hot spot region is removed primarily by heat conduction through Si-layer at the higher Joule heating level and the phonon nonlocality is mainly attributed to lower group velocity phonons as remarkably dissimilar to the case of electrons in laser heated plasmas. To validate these observations the modified phonon nonlocal model considering complete phonon dispersion relations is introduced as a correct form of the conventional theory. We also reveal that the relation between the phonon heat deposition time from the hot spot region and the relaxation time in Si-layer can be used to estimate the intrinsic thermal resistance in the parallel heat flow direction as Joule heating level varies.

• 한국식품저장유통학회지
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• 제11권1호
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• pp.130-133
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• 2004

고품질 참외 농축액을 제조하기 위해 농축공정에서 중요한 변수로 작용하는 가열온도 및 가열시간을 달리하면서 제조한 농축물에 대한 관능적 평가를 실시한 결과, 가열 후 맛이 최대평점을 나타낸 조건은 가열온도가 96.63$^{\circ}C$ 및 가열시간이 14.31 min일 때 였으며, 전반적인 기호도가 가장 높은 조건은 가열온도가 97.18$^{\circ}C$ 및 가열시간이 14.55 min일 때였다. 가열온도 및 가열시간을 달리하면서 실험한 결과 참외 농축액 제조를 위해서는 가열온도 98$^{\circ}C$로, 가열시간 13 min으로 처리하는 것이 적당하였다.