• Title/Summary/Keyword: low temperature heating

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The Effects of Low Temperature Heating and Mustard Oil on the Kimchi Fermentation (열처리 및 겨자유의 첨가가 김치 발효에 미치는 영향)

  • Hong, Wan-Soo;Yoon, Sun
    • Korean Journal of Food Science and Technology
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    • v.21 no.3
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    • pp.331-337
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    • 1989
  • In order to investigate the method for extension of shelf-life of Kimchi, the effect of low temperature heating and addition of mustard oil on pH and total acidity of Kimchi during storage at $15^{\circ}C$ were studied. Mustard oil was found to have the antimicrobial effect on the major lactic acid bacteria of Kimchi such as Lactobacillus plantarum, Lactobacillus brevis, Leuconostoc mesenteroides and Pediococcus cerevisiae, Addition of 200p.p.m. mustard oil, 0.1% mustard powder and 0.01% $H_2O_2$ to Kimchi effectively reduced the fermentation rate of Kimchi. Low temperature heating of salted cabbage and addition of 200p·p.m. mustard oil and 0.01% $H_2O_2$ to seasonings extented the time reaching optimum ripening of Kimchi about 2.5 times longer than control. Combination of low temperature heating, addition of mustard oil and $H_2O_2$ to seasonings and post low temperature heating delayed fermentation time Kimchi about 5 times longer than control after 15 days storage at $15^{\circ}C$.

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A Study on the Furnace Heating Characteristics Using Oxy-fuel Combustion (순산소 연소를 이용한 연소로 가열특성에 관한 실험적 연구)

  • Jeong, Yu-Seok;Lee, Eun-Kyung;Ko, Chang-Bok;Noh, Dong-Soon;Jang, Byung-Lok;Han, Hyung-Kee
    • 한국연소학회:학술대회논문집
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    • 2006.10a
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    • pp.229-234
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    • 2006
  • The oxy-fuel combustion heating characteristics is investigated experimentally by measuring furnace and steel temperature variations for batch type furnace simulator with a specially designed low NOx oxy-fuel burner. Economics of using oxy-fuel combustion is confirmed and, the furnace and steel temperature variations for different heating conditions are compared to deduce optimal heating control pattern for energy savings and rapid uniform heating. High $CO_2$ concentration (> 80-90%), low NOx (< 40ppm) and CO (< 10ppm) are measured in the flue gas. Temperature differences (< $30^{circ}C$) inside the furnace and steel are reduced relatively by increasing the burner jet momentum.

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Dielectric and Piezoelectric Characteristic of Low Temperature Sintering PMN-PNN-PZT Ceramics according to the Heating Rate (승온속도에 따른 저온소결 PMN-PNN-PZT 세라믹스의 유전 및 압전특성)

  • Kim, Kook-Jin;Yoo, Ju-Hyun;Hong, Jae-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.253-254
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    • 2007
  • In this study, in order to develop low temperature sintering multilayer piezoelectric actuator, PMN-PNN-PZT system ceramics were fabricated using $Li_2CO_3-Bi_2O_3$-CuO as sintering aids and their piezoelectric and dielectric characteristics were investigated as a function of heating rate. At sintering temperature of $900^{\circ}C$, with increasing heating rate, electromechanical coupling factor(kp), mechanical quality factor(Qm) and dielectric constant $({\varepsilon}_r)$ were increased.

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Evaluation of Heating and Cooling Thermal Output Characteristics of Prefabricated Steel Wall Panel System for Radiant Heating and Cooling (강판 마감형 조립식 벽패널 복사냉난방시스템의 냉난방 방열 특성 평가)

  • Lim, Jae-Han;Koo, Bo-Kyoung;Kim, Sung-Im;Song, Seung-Yeong
    • Journal of the Korean Solar Energy Society
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    • v.33 no.2
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    • pp.70-77
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    • 2013
  • Recently the radiant panel heating and cooling system has been regarded as an alternative of low temperature heating and high temperature cooling by applying the renewable energy sources to the heating and cooling of buildings. Especially this system can be used as HVAC system alternatives in super high-rise buildings for energy saving and thermal comfort. Also it can be possible to reduce the plenum space because the minimum ventilation air will be supplied into the space. This study focused on the evaluation the basic characteristics of thermal output in prefabricated steel wall panel system for radiant heating and cooling. In order to evaluate the thermal output according to both various supply water temperatures and supply water flow rates, three-dimensional dynamic heat transfer analysis was performed. As results, for the heating mode, thermal output increased by 26% with the supply temperature increasing by $5^{\circ}C$. The surface temperature of panels range within $1{\sim}3^{\circ}C$. For the cooling mode, thermal output decreased by 18.2% with the supply temperature increasing by $2^{\circ}C$. The surface temperature of panels range within $0.5{\sim}1^{\circ}C$ and it was shown the even temperature distribution.

A study on coil temperature bariation in 75% hydrogen batch annealing furnace (75% 수소 BATCH 소둔시에서의 코일 온도변화에 관한 연구)

  • Jeon, Eon-Chan;Kim, Soon-Kyung
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.2
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    • pp.173-181
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    • 1994
  • A Cold spot temperature control system for the batch annealing furnace has been estabilished in order to reduce energy consumption to improve productivity and stabilize the propertics of products. Therefore we confirmed a relation between annealing cycle time and atmospheric gas, variation of coil cold spot temperature with time during heating and actual temperature measurements at mid-width of each coil during heating and actual temperature measurements at mid-width of each coil during soaking. The results of the tempaeature variation effect on the batch annealing are as follows. 1) Heating time is reduced to one half with increasing atmospheric gas flow rate and changing of atmospheric gas component from HNx to Ax gas, and annealing cycle time is reduced to 2.7 times. 2) In case of short time healing, the slowest heating part is the center of B coil, in case of long time heating, the low temperature point moves from the center of coil to inside coil. And the temperature in this part is higher than other parts when cooling. When finished heating, the cold spot is located 1/3 of coil inside in case of HNx atmospheric gas. But center of coil in case of Ax atmospheric gas. 3) The outside of top coil is the highest temperature point when heating, which becomes the lowest temperature point when cooling. So, this point becomes high temperature zone at heating and low temperature zone at cooling, It has relation according to atmospheric gas component and flow rate. 4) Soaking time at batch annealing cycle determination is made a decision by the input coil width, and soaking time for quality homogenization of 1214mm width coil must be 2.5 hours longer than that of 914mm width coil for the same ciol weight. 5) Annealing cycle time with Ax atmospheric gas is extended 1 hour in of slow cooling during 5 hours in order to avoid rapid cooling.

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Experimental Study on Properties of Temperature History Using Heating Sheet and Insulation Form at Low Temperature (발열시트 및 단열재를 사용한 거푸집 내부 콘크리트의 저온환경하 온도이력 특성에 관한 실험적 연구)

  • Choi, Si-Hyun;Lee, Han-Seung;Choi, Hyun-Kuk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.21 no.4
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    • pp.132-139
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    • 2017
  • In this study, in order to prevent the frost damage of the concrete, the characteristics of the form using heating sheet utilizing the chemical reaction of quicklime and the insulation were evaluated through experiments at low temperature. In the case of form at $-10^{\circ}C$, the form with attached heating sheet showed a temperature history of more than $10^{\circ}C$ higher than that of wood form at the early of concreting due to heat of the quicklime in the heating sheet. In the case of the insulated form, the concrete was kept at a high temperature by preserving the hydration heat. When the heating sheet and the isopink(extruded polystyrene) were attached together on the form, the effect was the same as that of the vacuum insulation. The compressive strength of the form with vacuum insulation and form with isopink, heating sheet as measured about 5 MPa at age 3. The experimental in Mongolia, as with the pervious results, the form with the heating sheet and the insulation showed the highest temperature history over $25^{\circ}C$ for 48 hours. Therefore, it was confirmed that the heating sheet and insulation are attached to the form, which helps the concrete strength development at low temperature by heat generation and the insulation effect.

Development of High-Frequency Induction Heating Method Using Adhesive Waterproofing Sheet Laminated with Aluminum Sheet (알루미늄 박판 점착 복합 방수시트를 이용한 고주파 유도가열 방수공법 개발 평가 연구)

  • Kim, Yun Ho;Kim, Dong Bum;Park, Jin-Sang;Oh, Sang Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2011.05a
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    • pp.111-114
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    • 2011
  • Waterprooping Method with sheet need to study technology and multilateral verification considering the arctic conditions as low temperature and humidity, which is the result only considered of material aspects without environmental condition in construction But there are no measures up until now. To solve this problem by using high frequency induction heating method developed waterproof sheets, cold (5 ℃ or less) can be applied in a more stable environment, water-resistant materials and construction methods were studied for development. The results of the test showed that high frequency induction heating method is effective for usability in low temperature condition and securement of proper quality than existing Waterprooping Method with sheet need.

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Design and Simulation of Heating Rubber Roller for Laminating Process

  • Hur, Shin;Woo, Chang Su
    • Elastomers and Composites
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    • v.51 no.4
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    • pp.280-285
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    • 2016
  • The purpose of this study is to get optimum design and operation conditions of the heating rubber roller for laminating process. The cause of performance degradation of heating rubber roller is delamination of rubber on metal tube, rubber aging due to high temperature. We measured the material properties of thermal expansion, thermal conductivity, specific heat and density and analyzed thermal distributions of rubber layer using finite element method. As a result of heat/flow analysis, the density distribution of heating coil must shorten the stabilization time by reducing the temperature deviation on the length direction at the temperature rising section after increasing the density of the area contacting with the laminate film at the center part which is an opposite of the current composition while enabling to maintain the temperature of heater to be consistent while maintaining the temperature deviation to be low when heat loss is created. Finally, we determined optimum heating method of heating rubber roller.

Drying and Low Temperature Storage System of Agricultural Products using the Air to Air Heat Pump (II) - Performance of Low Temperature Storage for Apples - (히트펌프를 이용한 농산물 건조 및 저온저장 시스템 (II) - 사과의 저온저장 성능 -)

  • Kang, Y.K.;Han, C.S.;Keum, D.H.
    • Journal of Biosystems Engineering
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    • v.32 no.2 s.121
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    • pp.102-108
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    • 2007
  • Heat pump systems are recognized to be heating and cooing systems. In this study, to check the practical application possibility of heat pump systems as low temperature storage systems and get basic data, apples of a long term storage items were stored and performance of low temperature storage and quality changes of apples were evaluated. Cooling coefficient of performance of the system was from 1.1 to 1.3. Although ambient air temperature varied widely from $-13^{\circ}C$ to $29.6^{\circ}C$ during low temperature storage period from January to June, the average temperature of low temperature storage chamber was $1.1^{\circ}C$ at setting temperature of $1.5^{\circ}C$. Sucrose of apples stored by the heat pump decreased from initial sucrose of 15.4% (Brix number) to final sucrose of 14.3%. Weight loss ratio of apples was 9.7% and internal and external view of apples after low temperature storage were very satisfactory with the naked eye.

A Study on Application of Radiant Floor Heating in Large Space (대공간의 바닥 복사 난방 적용에 관한 연구)

  • Ahn, Min-Hee;Choi, Chang-Ho
    • Journal of the Korean Solar Energy Society
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    • v.27 no.3
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    • pp.79-85
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    • 2007
  • This paper addresses the indoor air quality when radiant floor heating is applied in large space. Radiant heat exchange between surfaces depends on the orientation and the temperature of the surfaces. Also, the temperature and the radiant characteristic of the wall and the roof that face the floor have great influence on the indoor air environment due to the largeness of the wall and the roof in large spaces. In this study, we simulate a test-cell(25X20X10) using a ies YE And using a CFD(microflo in VE), an indoor air environment was investigated to establish the optimum temperature of floor. At the first time of the heating, high floor temperature is demanded. At the middle of the heating, however, the temperature of the residential space was formed appropriately, although the temperature of the floor was set low.