• 제목/요약/키워드: Hot-Cold

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Crack Properties of Concrete depending on Changes in Surface-Covered Curing Materials in Hot Weather (서중환경에서 표면피복 양생재 변화에 따른 콘크리트의 균열특성)

  • Lee, Je-Hyun;Kim, Tae-Woo;Baek, Cheol;Lee, Sang-Un;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.11a
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    • pp.175-176
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    • 2017
  • Many problems in various aspects such as generation of plastic/dry contraction cracks and cold joints can be caused unless proper quality control measures are established in hot weather circumstances. Therefore, this study aimed to compare the crack patterns of concrete by applying a change in 3 surface curing methods such as a mono aluminum-deposited bubble sheet developed to reduce the temperature and cracks through reflection of heat in summer and a PE film and a surface exposure used generally to an actually constructed apartment slab. The study result confirmed that the best concrete crack reduction effect can be obtained with a mono aluminum-deposited bubble sheet.

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Effects of Taste and Quality of Drugs on the Plasma Corticosterone Level in Mice exposed to Heat and Cold Stress (한약(韓藥)의 기미(氣味)가 한열자극(寒熱刺戟)을 받은 생쥐의 혈중(血中) corticosterone에 미치는 효과(效果))

  • Nam Yeo-Jeong;Lee Tae-Hee
    • Herbal Formula Science
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    • v.10 no.1
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    • pp.157-167
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    • 2002
  • This study was performed to investigate what effect the taste and quality of drugs would have on the cold and heat mechanisms of human body. We administered Hwangryeunhaedok-tang composed of bitter-tasted, cold-qualified drugs and Gungangbuza-tang composed of spice-tasted. hot-qualified drugs, respectively to the mice 1 hr before exposure to heat stress or cold stress. Plasma corticosterone level of mice was measured. The results were as follows: 1. The elevated corticosterone level in the mice exposed to heat stress was significantly decreased after administration of Gungangbuza-tang but there was no decrease after administration of Hwangryeunhaedok-tang. 2. The elevated corticosterone level in the mice exposed to cold stress was significantly decreased after administration of Hwangryeunhaedok-tang but there was mild decrease after administration of Gungangbuza-tang. 3. When the doses, 3g/kg and 1g/kg were administerd to mice exposed to heat stress. both dose showed significant decrease of corticosterone level and the dose. 3g/kg was more effective. However, in the mice exposed to cold stress, the dose, 3g/kg showed mild decrease and 1g/kg showed significant decrease. These data suggested that HW decreased the plasma corticosterone level in the mice exposed to cold stress and GB also decreased the plasma corticosterone level in the mice exposed to heat stress. In conclusion, our study revealed that the taste and quality of drugs controled the cold and heat mechanism of human body.

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Differences of Cold-heat Patterns between Healthy and Disease Group (건강군과 질환군의 한열지표 차이에 관한 고찰)

  • Kim Ji-Eun;Lee Seung-Gi;Ryu Hwa-Seung;Park Kyung-Mo
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.20 no.1
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    • pp.224-228
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    • 2006
  • The pattern identification of exterior-interior syndrome and cold-heat syndrome is one of the diagnostic methods using most frequently in Oriental medicine. There was no systematic studies analyzing the characteristics of the 'exterior-interior and cold-heat' between healthy and disease group. In this study, cold-heat pattern, blood pressure, pulse rate, height and weight are recorded from 100 healthy subjects and 196 disease subjects with age ranging from 30 to 59 years. To analyze the differences between healthy and disease group, we used the descriptive statistics. And linear regression function, linear support vector machine and bayesian classifier were used for distinguishing healthy group from disease group. The score of both exterior-heat and interior-cold in healthy group is higher than the score in disease group. This means that if one belongs to the disease group, his(or her) exterior gets cold and his interior gets hot. And also, these result have no relevance to age. But, the attempt to classify healthy group from disease group with a exterior-interior and cold-heat and other vital signs did not have good performance. It mean that even though they have a different trend each other, only these kinds of information couldn't classify healthy group and disease group.

A Study on the Performance of 100 W Thermoelectric Power Generation Module for Solar Hot Water System (태양열 온수 시스템에 적용 가능한 100 W급 열전발전 모듈 성능에 관한 연구)

  • Seo, Ho-Young;Lee, Kyung-Won;Yoon, Jeong-Hun;Lee, Soon-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.39 no.1
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    • pp.21-32
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    • 2019
  • Solar hot water system produces hot water using solar energy. If it is not used effectively, overheating occurs during the summer. Therefore, a lot of research is being done to solve this. This study develops thermoelectric power module applicable to solar hot water system. A thermoelectric material can directly convert thermal energy into electrical energy without additional power generation devices. If there is a temperature difference between high and low temperature, it generate power by Seebeck effect. The thermoelectric module generates electricity using temperature differences through the heat exchange of hot and cold water. The water used for cooling is heated and stored as hot water as it passes through the module. It can prevent overheating of Solar hot water system while producing power. The thermoelectric module consists of one absorption and two radiation part. There path is designed in the form of a water jacket. As a result, a temperature of the absorption part was $134.2^{\circ}C$ and the radiation part was $48.6^{\circ}C$. The temperature difference between the absorption and radiation was $85.6^{\circ}C$. Also, The Thermoelectric module produced about 122 W of irradiation at $708W/m^2$. At this time, power generation efficiency was 2.62% and hot water conversion efficiency was 62.46%.

DEVELOPMENT ON ENHANCED LEAKED FUEL RECIRCULATION DEVICE OF LPLi ENGINE TO SATISFY SULEV STANDARD

  • Myung, C.L.;Kwak, H.;Park, S.
    • International Journal of Automotive Technology
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    • v.7 no.4
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    • pp.407-413
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    • 2006
  • The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.

A Study on the Improvement of Indoor Thermal and Air Environment Made by Ceiling Cassette Type Cooling and Heating Unit in Classrooms (천장 카세트형 냉·난방기에 의해 형성되는 학교 교실의 실내 열환경 및 공기환경의 개선에 대한 연구)

  • Chang, Hyun-Jae;Lee, Ha-Young
    • Journal of the Korean Solar Energy Society
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    • v.32 no.6
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    • pp.141-148
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    • 2012
  • Ceiling cassette type air conditioner has been a main stream as a heating/cooling system recently in school, Korea. In this study, indoor thermal environments made by ceiling cassette type air conditioner were investigated by CFD simulation. Concentrations of $CO_2$ were investigated by a field measurement. Indoor thermal environment with the velocity inlet angle of $45^{\circ}$ from the ceiling in heating season was very ununiform so that thermal area was divided into two parts those the one is window side which is cold, and the other is corridor side which is hot. In cooling season under the same condition, there are areas too hot or too cold. If the velocity inlet angle is set in $30^{\circ}$ from the ceiling, indoor thermal environments was improved greatly in cooling season and heating season, too. Also, from the field measurement of $CO_2$ concentrations, it was suggested to install ventilators with proper air volume considered the number of class students.

Evaluation of Aisle Partition System's Thermal Performance in Large Data Centers for Superior Cooling Efficiency (데이터센터의 공조효율 향상을 위한 공조파티션시스템 성능평가에 관한 연구)

  • Cho, Jin-Kyun;Jeong, Cha-Su;Kim, Byung-Seon
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.22 no.4
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    • pp.205-212
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    • 2010
  • In a typical data center, large numbers of IT sever racks are arranged multiple rows. IT environments, in which extensive electronic hardware is air-cooled, cooling system inefficiencies result when heated exhaust air from equipment prematurely mixes with chilled coolant air before it is used for cooling. Mixing of chilled air before its use with heated exhaust air results in significant cooling inefficiencies in many systems. Over temperatures may not only harm expensive electronic equipment but also interrupt critical and revenue generating services. Cool shield is a cost effective aisle partition system to contain the air in cold aisles and hot aisles of an IT server room. This paper focuses on the use of performance metrics for analyzing aisle partition system in data centers.

Case Studies for Optimizing Heat Exchanger Networks in Steam-assisted Gravity Drainage Oil Sands Plant (SAGD 법을 이용한 오일샌드 플랜트 열교환기망 최적화를 위한 사례연구)

  • Cho, Eunbi;Jeong, Moon;Kang, Choonhyoung
    • The KSFM Journal of Fluid Machinery
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    • v.19 no.3
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    • pp.19-24
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    • 2016
  • Oil sands are a mixture of sand, clay, and a high-viscosity petroleum called bitumen. Steam-Assisted Gravity Drainage (SAGD) is the most viable and environmentally safe recovery technology for extracting bitumen. It extracts the viscosity-lowered bitumen by high pressure, high temperature steam injected into the bitumen reservoir. The steam is produced at the Central Processing Facility (CPF). Typically, more than 90% of the energy consumed in producing bitumen are used to generate the steam. Fuels are employed in the process, which cause economic and environmental problems. This paper explores the retrofit of heat exchanger network to reduce the usage of hot and cold utilities. The hot and cold utilities are reduced respectively 6% and 37.3% which in turn resulted in 5.3% saving of total annual cost by improving the existing heat exchanger network of the CPF.

A Study on Assessing Disaster Response Capacity for Coastal Residents (연안거주민에 대한 재해대응능력 평가 연구)

  • Kang, Tae-Soon;Lee, Seung-Rok;Lee, Jong-Sup;Kim, Jongkyu
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.5
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    • pp.979-990
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    • 2014
  • Recently the frequency of coastal disasters caused by global warming is increasing and the damage is becoming greater. Therefore, the Korean government is establishing various policies and measures to minimize damage. For disaster prevention, this study will evaluate the disaster response capacity of each local resident(Eup/Myeun/Dong) in coastal areas through the survey. The purpose of this study is to quantitatively understand the disaster response capacity and analyze spatial autocorrelation between hot spots(vulnerable area) and cold spots. Thus this study was conducted a survey of 311 towns(Eup/Myeun/Dong) about the disaster response capacity of coastal residents. As a result, Namhae has the highest average score(4.9). On the contrary, Hampyeong has the lowest(1.6). Coastal residents in Namhae seem to have better understanding of first aid and preventive maintenance. But coastal residents in Hampyeong seem to not have these characteristics. Afterwards, this study builds a database of disaster response capacity, and analyzes it using the spatial autocorrelation method. Finally, the area of hot spots and cold spots for disaster response capacity was quantitatively detected.

A Mushroom-Rice(Ganoderma lucidum) development which uses the brown rice (현미를 이용한 영지버섯쌀 생산)

  • 정인창;곽희진
    • Journal of Applied Tourism Food and Beverage Management and Research
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    • v.14 no.1
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    • pp.47-58
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    • 2003
  • Brown rice was used as material for solid-substrate cultivation of Ganoderma lucidum. The hydration time with cold water appeared to be 10 hours for brown rice, but the final water content was much less than optimum water content(65%). Hot water reduced the hydration time of brown rice, and the water content reached to 65% within 40 mins. From this result, hot water was better than cold water for the hydration of brown rice. We attempted to develop a practically applicable process by combining the soaking and sterilization. The water content of 65% appeared to be the best for the growth of the fungi and production of glucosamine related to the amount of mycelium. The content of free sugar increased far more in brown rice fermented with mycelium than in brown rice which was not fermented. Addition was most suitable 20% when add mushroom-rice to brown rice.

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