• Title/Summary/Keyword: Total heat

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A Study on the Heat Hazard Assessment of Building Wood (건축용 목재의 열 유해성 평가에 대한 연구)

  • Woo, Tae-Young;Jin, Eui;Chung, Yeong-Jin
    • Fire Science and Engineering
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    • v.32 no.5
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    • pp.6-14
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    • 2018
  • This study was carried out with respect to the heat release rate (HRR) properties of building wood. Heat release characteristics were measured using a cone calorimeter (ISO 5660-1) with four kinds of wood. The time to ignition measured after the combustion in $25kW/m^2$ external heat flux was 35 to 55 s. Time to ignition of both lauan and red pine was marked with the most delayed value in each of 54 s, 55 s. The maximum heat release rate ($HRR_{peak}$) was $156.87{\sim}235.1kW/m^2$, and the risk of early fire was highest in spruce. Total heat release of red pine was obtained in the highest value with $114.2MJ/m^2$. The mean effective heat of combustion of Japanese cedar was 19.1 MJ/kg and the highest among the samples. Fire risk of wood by FPI was orderly increased from lauan ($0.2468s{\cdot}m^2/kW$), red pine ($0.2339s{\cdot}m^2/kW$), spruce ($0.2308s{\cdot}m^2/kW$) to Japanese cedar ($0.2231s{\cdot}m^2/kW$). Fire risk of wood by FGI get increased from lauan ($0.5088kW/m^2{\cdot}s$), red pine ($0.5111kW/m^2{\cdot}s$), Japanese cedar ($2.8522kW/m^2{\cdot}s$) to spruce ($3.0662kW/m^2{\cdot}s$). Therefore, the risk of fire on the heat release characteristics of woods were found that spruce and Japanese cedar showed the high value compared with the other specimens.

Sensitivity Analyses for Maximum Heat Removal from Debris in the Lower Head

  • Kim, Yong-Hoon;Kune Y. Suh
    • Nuclear Engineering and Technology
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    • v.32 no.4
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    • pp.395-409
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    • 2000
  • Parametric studies were performed to assess the sensitivity in determining the maximum in-vessel heat removal capability from the core material relocated into the lower plenum of the reactor pressure vessel (RPV)during a core melt accident. A fraction of the sensible heat can be removed during the molten jet delivery from the core to the lower plenum, while the remaining sensible heat and the decay heat can be transported by rather complex mechanisms of the counter-current flow limitation (CCFL) and the critical heat flux (CHF)through the irregular, hemispherical gap that may be formed between the freezing oxidic debris and the overheated metallic RPV wall. It is shown that under the pressurized condition of 10MPa with the sensible heat loss being 50% for the reactors considered in this study, i.e. TMI-2, KORI-2 like, YGN-3&4 like and KNGR like reactors, the heat removal through the gap cooling mechanism was capable of ensuring the RPV integrity as much as 30% to 40% of the total core mass was relocated to the lower plenum. The sensitivity analysis indicated that the cooling rate of debris coupled with the sensible heat loss was a significant factor The newly proposed heat removal capability map (HRCM) clearly displays the critical factors in estimating the maximum heat removal from the debris in the lower plenum. This map can be used as a first-principle engineering tool to assess the RPV thermal integrity during a core melt accident. The predictive model also provided ith a reasonable explanation for the non-failure of the test vessel in the LAVA experiments performed at the Korea Atomic Energy Research Institute (KAERI), which apparently indicated a cooling effect of water ingression through the debris-to-vessel gap and the intra-debris pores and crevices.

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Heat Transfer and Total Friction Factors in the Convergent Channels with V/⋀-shaped Ribs on Two Opposite Walls (양 벽면에 V/⋀형 리브가 있는 수축 채널의 열전달과 전 마찰계수)

  • Lee, Myung-Sung;Heo, Meo-Seong;Jeong, Ui-Jae;Park, Young-Joon;Yoo, Jung-Hyun;Im, Gun-Woo;Ahn, Soo-Whan
    • Journal of Power System Engineering
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    • v.20 no.5
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    • pp.66-71
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    • 2016
  • The measurements of heat transfer and total friction factors for turbulent flows in the convergent rectangular channels with two opposite in-line ribbed walls are reported. The study has covered three different angled ribs ($30^{\circ}$, $45^{\circ}$ and $60^{\circ}$) and Reynolds number in the range of 22,000 to 75,000. The channel, composing of ten isolated copper sections in the length of test section of 1 m, has the channel convergence ratio of $D_{ho}/D_{hi}=0.67$. The results show that the ribs pointing downstream (${\wedge}-shaped$) is somewhat greater than the ribs pointing upstream (V-shaped) in the dimensionless Nusselt number and total friction factors.

Effect of heat stress on growth performance and blood profiles in finishing pigs

  • Kim, Byeonghyeon;Kim, Hye Ran;Kim, Ki Hyun;Kim, Minji;Baek, Youl-Chang;Lee, Sung Dae;Jeong, Jin Young
    • Korean Journal of Agricultural Science
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    • v.47 no.3
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    • pp.683-691
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    • 2020
  • A biomarker is needed to monitor and manage the health of pigs from heat stress (HS). Therefore, we investigated the effects of HS on growth performance, nutrient digestibility, and blood profiles in finishing pigs. A total of 12 finishing pigs (n = 12) were raised in thermal neutral (TN; 25℃) conditions for a 3-d adaptation period. After the adaption, 6 pigs were exposed to HS at 33℃ (HS33) for 5 d. The pigs were fed the same diet based on corn and soybean meal. Chromic oxide was added to all the diets at a level of 2 g·kg-1 as an indigestible marker for the determination of the apparent total track digestibility (ATTD) of nutrients and amino acids. Blood samples were collected after the adaptation and heat treatment to verify the blood profiles. The HS33 pigs had a lower (p < 0.01) average daily feed intake (ADFI) and higher (p < 0.05) rectal temperature compared to the TN pigs. However, there was no difference in the ATTD of nutrients and amino acids. The HS33 pigs had reduced (p < 0.05) levels of serum glucose, non-esterified fatty acids (NEFA), total protein, albumin, and calcium compared to the TN pigs. However, the level of total bilirubin was increased (p < 0.05) in the HS pigs. In conclusion, HS reduced the feed intake and had an adverse effect on health. Altered blood profiles as a result of a negative energy balance are expected to be biomarkers of HS in finishing pigs.

The Measurement of Seasonal Evapotranspiration above Corn Canopy Based on the Bowen ratio-Energy Balance Method (보우엔비(比)-에너지수지방법(收支方法)에 의한 옥수수군락(群落) 증발산(蒸發散)의 계절별(季節別) 관측(觀測))

  • Lee, Yang-Soo;Im, Jeong-Nam;Kang, Young-Hee
    • Korean Journal of Soil Science and Fertilizer
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    • v.21 no.1
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    • pp.15-19
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    • 1988
  • Heat energy distribution forming net radiation above corn canopy was determined by means of the Bowen ratio-energy balance method. Total-global solar radiation above crop canopy during the growing season was $1,559MJm^{-2}$ and total latent heat flux density was $960MJm^{-2}$. The data showed that 61.6% of the global solar radiation was used for a heat source of evapotranspiration (ETa) above corn canopy. Mean daily ETa ranged from 2.7 to 5.6mm. Total ETa, total drymatter, and water use efficiency were 394mm, $2,214gm^{-2}$, and $5.6gm^{-2}mm^{-1}$, respectivively.

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HEAT PIPE TYPE EXHAUST HEAT RECOVERY SYSTEM FOR HOT AIR HEATER

  • Kang, G.C.;Kim, Y.J.;Ryou, Y.S.;Rhee, K.J.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2000.11c
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    • pp.654-661
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    • 2000
  • Area of greenhouse increases rapidly up to 45,265ha by the year of 1998 in Korea. Hot air heater with light oil combustion is the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat of the oil combusted in the furnace. In order to recapture the heat of this exhaust gas and to recycle for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The exhaust heat recovery system was made for space heating in the greenhouse. The system consisted of a heat exchanger made of heat pipes, ${\emptyset}15.88{\times}600mm$ located in the rectangular box of $600{\times}550{\times}330mm$, a blower and air ducts. The rectangular box was divided by two compartments where hot chamber exposed to exhaust gas in which heat pipes could pick up the heat of exhaust gas, and by evaporation of the heat transfer medium in the pipes it carries the heat to the cold compartment, then the blower moves the heat to greenhouse. The number of heat pipe was 60, calculated considering the heat exchange amount between flue gas and heat transfer capacity of heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/hr depending on the inlet air temperature of 12 to $-12^{circ}C$ respectively when air flow rate $1,100\textrm{m}^3/hr$. The exhaust gas temperature left the heat exchanger dropped to $100^{circ}C$ from $270^{circ}C$ by the heat exchange between the air and the flue gas, the temperature difference was collected by the air and the warm air temperature was about $60^{circ}C$ at the air flow rate of $1,100\textrm{m}^3/hr$. This heat pipe type exhaust heat recovery system can reduce fuel cost by 10% annually according to the economic analysis.

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Spectral Weighted-Sum-of-Gray-Gases Modeling of Narrow Band for Prediction of Radiative Heat Transfer Induced from Liquid Engine Plume (액체 엔진 플룸 복사 열전달 예측을 위한 파장별 회체가스 중합법의 좁은밴드 적용)

  • Ko, Ju-Yong;kim, In-Sun
    • Aerospace Engineering and Technology
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    • v.8 no.1
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    • pp.17-25
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    • 2009
  • The precise calculation of gas absorption coefficient in the radiative transfer equation is very important to the prediction of radiative heat transfer induced from liquid engine plume in view of base insulation design. For this purpose, the WNB model for gas absorption coefficient is described with the selection of important parameters and then the calculated results are compared with those of SNB model for validation. Total emissivity, narrow band averaged intensity and total intensity are calculated and compared to the results of SNB model. As results, the total emissivity and the total intensity are well matched within 3.1% and roughly 5 % error, respectively. Moreover, the gas modeling database is constructed with estimation of the combustion gas composition of $CO_2$ and $H_2O$ for liquid engine plume.

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A Case Report of Soyangin Adult Atopic Dermatitis Patient Treatment with Soyangin Formulae (소양인(少陽人) 처방을 활용한 성인형 아토피피부염 치험 1례(例))

  • Han, Su-Jin;Song, Jeong-Mo
    • Journal of Sasang Constitution and Immune Medicine
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    • v.21 no.3
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    • pp.178-185
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    • 2009
  • 1. Objectives: The purpose of this case study is to evaluate the effects of Sasang constitutional therapy and treatment of an adult atopic dermatitis patient, who was diagnosed Soyangin, Interior febrile disease induced from the stomach affected by heat(少陽人 胃受熱裏熱病). 2. Methods: The adult Atopic Dermatitis patient was diagnosed Soyangin, Interior febrile disease induced from the stomach affected by heat(少陽人 胃受熱裏熱病) which was based on his Nature & Emotion(性情), physical characteristics, symptoms. He was medicated with Prescriptions of Soyangin. 3. Results and Conclusions: The clinical evaluation was made by SCORAD index, Total eosinophil count and Total IgE. After treatment, his SCORAD results significantly decreased from 88.4 to 21.9, Total eosinophil count decreased from 1320 to 120 and Total IgE also decreased from 1406.6 to 897.3. And the patient's subjective symptom and gerneral condition considerably improved after treatment. This case study describe the effectiveness on adult Atopic Aermatitis symptom by using Prescriptions of Soyangin.

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Physical Properties and Flame Retardency of Polyhydroxyamides (PHAs) Having Pendant Groups in the Main Chain (주사슬에 곁사슬기를 갖는 폴리히드록시아미드의 물성 및 난연특성)

  • Yoon, Doo-Soo;Choi, Jae-Kon;Jo, Byung-Wook
    • Polymer(Korea)
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    • v.30 no.6
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    • pp.478-485
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    • 2006
  • Physical properties and flammability of polyhydroxyamides (PHAs) haying poly (ethylene-glycol) methyl ether (MPEG) and/or dimethylphenoxy pendants were studied by using DSC, TGA, FTIR, pyrolysis combustion flow calorimeter (PCFC), and X-ray diffractometer. The degradation temperatures of the polymers were recorded in the ranges of $276{\sim}396^{\circ}C$ in air. PCFC results showed that the heat release (HR) capacity and total heat release (total HR) values of the PHAs were increased with in-creasing molecular weight of MPEG. In case of M-PHA 2 annealed at $290^{\circ}C$, the values of HR capacity were siginificantly decreased from 253 to 42 J/gK, and 60% weight loss temperatures increased from 408 to $856^{\circ}C$ with an annealing temperature. The activation energy for the decomposition reaction of the PHAs showed in the range of $129.3{\sim}235.1kJ/mol$, which increased with increasing conversion. Tensile modulus of PHAs were decreased as increasing chain of MPEG, and showed an increase more than initial modulus after converted to PBOs.

Effects of Heat Treatments on the Antioxidant Activities of Fruits and Vegetables (과채류의 항산화 활성에 미치는 열처리 효과)

  • Kim, Hyun-Young;Woo, Koan-Sik;Hwang, In-Guk;Lee, Youn-Ri;Jeong, Heon-Sang
    • Korean Journal of Food Science and Technology
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    • v.40 no.2
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    • pp.166-170
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    • 2008
  • The effects of heat treatments on the antioxidant activities of selected fruits and vegetables were investigated by heating at various temperatures (110, 120, 130, 140, and 150$^{\circ}C$) for 2 hr. The examined fruits and vegetables included tomatoes (Lycopersicon esculentum), oriental melon (Cucumis melon var. makuwa), apples (Malus pumila Miller var. domestica Schneider), melon (Cucumis melon), watermelon (Citrullus vulgaris), and banana (Musa sapientum). The total polyphenol and total flavonoid contents of the juices from heated samples were quantified spectrophotometrically, and their antioxidant activities were determined using DPPH and ABTS radicals. As the heating temperature increased, antioxidant activity also increased. The highest total polyphenol content (2.80 mg/g) occurred in the oriental melon with heating at 150$^{\circ}C$, and this value was 7 times higher than that of the untreated oriental melon (0.40 mg/g). The highest total flavonoid content (148.80 ${\mu}$g/g) occurred in the melon heat treated at 150$^{\circ}C$, and this value was 37 times higher than that of the untreated melon (4.54 ${\mu}$g/g). DPPH radical-scavenging activity was the highest in the watermelon treated at 150$^{\circ}C$ (84.37%, 0.50 mg/g), and this value was 40 times higher than that of the untreated watermelon. Finally, the highest ascorbic acid (AA) equivalent antioxidant capacity (AEAC) value (239.50 mg AA eq/g) was obtained in the watermelon heat treated at 150$^{\circ}C$ for 2 hr (control = 18.35 mg AA eq/g).