• Title/Summary/Keyword: heat combination

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Temperature History of Mock-up Mass Concrete Considering Different Heat Generation Due to Mixture Adjustment (수화발열량이 다른 콘크리트조합 모의부재 매스콘크리트의 온도이력 특성)

  • Kim Jong;Jeon Chung-Keun;Shin Dong-An;Yoon Gi-Won;Oh Seon-Kyo;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.9-12
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    • 2005
  • This paper investigated the temperature history of mass concrete mock up structure considering different heat generation by varying with mixture proportion. Setting time difference between high early strength mixture (E-P) and retarding mixture (R-F30) was 14.5hours. Incorporation of $30\%$ of fly ash contributed to $10^{\circ}C$ of hydration heat reduction. In generally used C and D combination, bottom concrete shows earlier hydration, while E-J combination showed reverse tendency and thus, this method can reduce the crack occurrence. Therefore, heat generation difference method has beneficial effect on reducing crack induced by hydration heat resulting from heat generation difference between surface and center section.

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Experimental and Modelling Study of the Denaturation of Milk Protein by Heat Treatment

  • Qian, Fang;Sun, Jiayue;Cao, Di;Tuo, Yanfeng;Jiang, Shujuan;Mu, Guangqing
    • Food Science of Animal Resources
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    • v.37 no.1
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    • pp.44-51
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    • 2017
  • Heat treatment of milk aims to inhibit the growth of microbes, extend the shelf-life of products and improve the quality of the products. Heat treatment also leads to denaturation of whey protein and the formation of whey protein-casein polymer, which has negative effects on milk product. Hence the milk heat treatment conditions should be controlled in milk processing. In this study, the denaturation degree of whey protein and the combination degree of whey protein and casein when undergoing heat treatment were also determined by using the Native-PAGE and SDS-PAGE analysis. The results showed that the denaturation degree of whey protein and the combination degree of whey protein with casein extended with the increase of the heat-treated temperature and time. The effects of the heat-treated temperature and heat-treated time on the denaturation degree of whey protein and on the combination degree of whey protein and casein were well described using the quadratic regression equation. The analysis strategy used in this study reveals an intuitive and effective measure of the denaturation degree of whey protein, and the changes of milk protein under different heat treatment conditions efficiently and accurately in the dairy industry. It can be of great significance for dairy product proteins following processing treatments applied for dairy product manufacturing.

Reduction of Hydration heat of FA concrete using Coal Gasification Slag for Mixed Fine Aggregate (석탄 가스화 용융 슬래그를 혼합 잔골재로 사용한 FA 치환 콘크리트의 수화열 저감)

  • Han, Jun-Hui;Lee, Young-Jun;Choi, Il-Kyung;Kim, Jung;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.79-80
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    • 2019
  • This study was intended to examine the possibility of reducing hydration heat by FA substitution and combination of slag (CGS) from coal gasification power generation (IGCC) with mixed aggregate for concrete. The analysis results showed good results if liquidity increases as the ratio of CGS increases, air volume decreases, and compressive strength is mixed up to 25% in the residual aggregate. The results showed that the heat of hydration was reduced compared to plain due to the boron content of CGS as the CGS substitution rate increased, but it was larger due to the combination with FA substitution. It was found that the heat of hydration was reduced.

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A Study on Beat Transfer Characteristics in the Air Side of Large-scaled Heat Exchanger (확대모형 열교환기를 이용한 공기측 열전달 성능에 관한 연구)

  • Byun Ju-Suk;Lee Jinho;Hong Man-Gi;Jeon Chang-Duk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.9 s.240
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    • pp.1032-1041
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    • 2005
  • This study is performed to investigate the heat transfer characteristics of heat exchanger according to the arrangement of fins as well as fin configuration by using the four times enlarged model. Friction factor, Colburn j factor and goodness factors are compared to each other to estimate performance of each case for 4 different kinds of fins, which are plain, single side slit, double side slit and louver fin. Results show that heat transfer would be altered by fin arrangement and that friction loss is more affected by fin configurations than by the fin arrangements. In particular, heat transfer depends more on the shape of front row than that of rear row. The heat transfer rate of combined fin arrangement increases a lot more under the same pressure drop than that of conventional fin arrangement. This indicates that the heat exchanger of higher efficiency would be designed by the proper combination of fins, of different shapes.

Optimization of spent nuclear fuels per canister to improve the disposal efficiency of a deep geological repository in Korea

  • Jeong, Jongtae;Kim, Jung-Woo;Cho, Dong-Keun
    • Nuclear Engineering and Technology
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    • v.54 no.8
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    • pp.2819-2827
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    • 2022
  • The disposal area of a deep geological repository (DGR) for the disposal of spent nuclear fuels (SNFs) is estimated considering the spacing between deposition holes and between disposal tunnels, as determined by a thermal analysis using the decay heat of a reference SNF. Given the relatively large amount of decay heat of the reference SNF, the disposal area of the DGR is found to be overestimated. Therefore, we develop a computer program using MATLAB, termed ACom (Assembly Combination), to combine SNFs when stored in canisters such that the decay heat per canister is evenly distributed. The stability of ACom was checked and the overall distribution of the decay heat per canister was analyzed. Finally, ACom was applied to disposal scenarios suggested in the conceptual design of a DGR for SNFs, and it was confirmed that the decay heat per canister could be evenly distributed and that the maximum decay heat of the canister could be much lower than that of a canister estimated using a reference SNF. ACom can be used to improve the disposal efficiency by reducing the disposal area of a DGR for SNFs by ensuringg a relatively even distribution of decay heat per canister.

Systematic Review and Meta-Analysis of Efficacy and Safety of Fire Needling and Warm Needling on Acute Gout

  • Ji Hye Hwang;Aejin Song;Ho-Sueb Song
    • Journal of Pharmacopuncture
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    • v.25 no.4
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    • pp.301-316
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    • 2022
  • Objectives: This study aimed to evaluate the efficacy and safety of heat stimuli (e.g., fire needling, warm needling) in acupuncture for acute gout. Methods: Four international online databases (PubMed, Cochrane, Embase, and Chinese National Knowledge Infrastructure) were searched to identify randomized, controlled trials (RCTs) that used fire needling and warm needling for acute gout. The methodological quality of the RCTs was evaluated using the Cochrane risk-of-bias (RoB) tool. Thirteen RCTs (840 patients) were included and analyzed. Three evaluation tools (total effective rate, uric acid level, and pain score) were mainly used. Comparisons were made between Western medicine (WM) and i) fire needling or warm needling treatment alone, ii) fire needling and bloodletting combination treatment, iii) combination of fire needling, bloodletting, and herbal medicine, iv) warm needling (concurrently). Heat stimuli in acupuncture alone or in combination treatment were more effective in terms of the total efficacy rates, uric acid levels, and pain scores than WM alone. Results: In all the evaluation tools, the treatment effects in the fire needling alone or warm needling alone treatment group and the fire needling and bloodletting combination intervention group were significantly better than those in the WM control group. The warm needling and WM combination intervention groups also experienced significantly better treatment effects in terms of total efficacy rates and uric acid levels. Only the pain scores in the fire needling, bloodletting, and herbal medicine combination groups demonstrated significant improvement. Only four studies mentioned adverse reactions: one reported loss of appetite; three studies reported none. According to the Cochrane RoB tool, most studies showed either high or uncertain RoB. Conclusion: Heat stimuli during acupuncture could be effective for acute gout. However, as the included studies were regionally biased, more high-quality studies are needed to confirm the level of evidence.

A study on an experimental basis a special character of insulating oil the use of a transformers (변압기용 절연유의 특성에 관한 실험적 연구)

  • Kim, Sung-Dae;Park, Il-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.11
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    • pp.5188-5193
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    • 2011
  • This research is for temperature control of insulating oil inside the transformer. After I designed and manufactured various systems using Peltier element, which was thermal element, and Heat pipe, which was a cooling system, without electric power. The optimum system could be made by applying them to the temperature control for the insulating oil. I could verify that the combination type of Heat pipe 100 W+ Peltier 100W has a more outstanding capacity than pure Heat pipe 300 W within 60 degrees Celsius through experiments. Through this, I verify that the method of a proper design is prominent, and make an attempt at contribution to power saving effect and more effective control of Distributing board by using this combination type.

Effects of regenerator and cooler on the cooling performance of a vuilleumier cycle heat pump (재생기 및 냉각기가 VM열펌프의 냉방성능에 미치는 영향)

  • Lee, G.T.;Kang, B.H.;Yoo, H.;Lee, J.H.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.9 no.3
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    • pp.333-342
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    • 1997
  • An experimental study has been carried out to investigate the effects of the combination of the different wire mesh number in a regenerator and the tube number in a cooler on the cooling performance of a Vuilleumier cycle heat pump. Effects of operating conditions, such as charging pressure, operating speed, and heat input, on the cooling performance are also studied. The experimental results obtained indicate that the cooling performance could be improved with the proper combination of different wire meshes in a regenerator. More tubes in a cooler are desirable for better cooling performance. It is also found that the cooling capacity is enhanced, whereas COP is reduced with an increase in the heater tube temperature and the revolution speed. Both the cooling capacity and COP are incereased with a higher charging pressure.

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A Study on the Resetting of Incremental Heat Rate Curve of Combined Cycle Unit by Combination (복합발전기 조합별 증분비 곡선 재설정에 관한 연구)

  • Hong, Sang-Beom;Choi, Jun-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.68 no.1
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    • pp.8-12
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    • 2019
  • Combined Cycle Unit(CC) generates the primary power from the Gas Turbine(GT) and supplies the remaining heat of the GT to the Steam Turbine(ST) to generate the secondary power from the ST. It plays a major role in terms of energy efficiency and Load Frequency Control(LFC). Incremental Heat Rate(IHR) curves of economic dispatch(ED) of CC is applied differently by GT/ST combination. But It is practically difficult because of performance test by all combinations. This paper suggests a reasonable method for estimating IHR curves for partial combinations(1:1~(N-1):1) using IHR curves when operating with GT alone(1:0) and with all(N:1) combinations of CC.

Experimental Study on Cooling Performance of Multi-Heat Pump by Indoor-Unit Combination (실내기 조합에 따른 3실형 열펌프의 냉방성능 실험연구)

  • Kwon, Young-Chul;Chun, Chong-Keun;Park, Youn-Chang;Ko, Kok-Won;Seo, Dong-Nam
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.6
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    • pp.1487-1493
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    • 2008
  • In order to investigate the cooling capacity of multi-heat pump applying an inverter compressor, the experiment on the cooling performance characteristics of heat pump with 3 indoor units was performed under the cooling standard and cooling low-temperature conditions. The system data were measured by the psychrometric calorimeter. The operation characteristics and the behavior of the cooling cycle of the heat pump with 3 indoor units were understood from the cooling capacity, COP, and P-h diagram by indoor-unit combination. The operating load and performance of the multi-heat pump depends on the indoor-unit combination. The cooling capacity and COP of the low temperature condition were larger than those of the standard one. Also the cycle was analyzed by using P-h diagram.