• Asian-Australasian Journal of Animal Sciences
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• 제7권3호
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• pp.357-362
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• 1994

Five adult sheep were exposed to intermittent cold for 12 h (18:00-06:00) at an air temperature of $5{\pm}1^{\circ}C$ followed by 12 h (06:00-18:00) at $25{\pm}2^{\circ}C$ over a period of 8 days continuously. Carotid artery blood (Tc), mean skin (Ts) and mean body (Tb = 0.86 Tc + 0.14 Ts) temperatures, heat production rate (HP), respiratory evaporative heat loss, respiration rate (RR) and volume were measured before and after exposure. Tc during the 12 h cold period of intermittent cold exposure was similar to that during the corresponding period in the warm environment, while Tc in the $25^{\circ}C$ of intermittent cold was higher (p < 0.05) than that in the corresponding period in the warm environment. Ts during the cold period markedly decreased (p < 0.001) by about $9^{\circ}C$ when compared with that in the corresponding time period in the warm environment, while Ts during the $25^{\circ}C$ period of intermittent cold recovered to a similar level to that in the warm environment. Tb was lower (p < 0.001) during the cold period of intermittent cold, whereas a slight increase in Tb during the $25^{\circ}C$ period of intermittent cold was significant (p < 0.05) when compared with the value during the similar period in the warm environment. HP was greatly increased (p < 0.001) by cold exposure, followed by an immediate decrease during the first one hour of the 12 h warm period, reaching a similar level to that in the warm environment. A lower (p < 0.05) RR was observed during both the cold and $25^{\circ}C$ period of intermittent cold than during the corresponding periods in the warm environment. The results of the present investigation clearly show that the body temperature of sheep increased during a 12 h warm period following 12 h of exposure to cold. These results suggest that during a warm period of an intermittent cold exposure cycle, heat could be shored in the animal body.

• 설비공학논문집
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• 제29권5호
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• pp.259-268
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• 2017

This paper proposes a hydrogen-based social economy derived from fuel cells capable of replacing fossil fuels and resolving global warming, It thus provides an entry for developing economically feasible social configurations to make use of bio-hydrogen production systems. Bio-hydrogen production works from the principle that microorganisms decompose water in the process of converting CO to $CO_2$, thereby producing hydrogen. This study parts from an analysis of an existing 157-ton class NA1 bio-hydrogen reactor that identifies the state of feedstock and reactor conditions. Based on this analysis, we designed a 1-ton class bio-hydrogen reactor process simulator. We carried out thermal analyses of biological heat reactions, sensible heat, and heat radiation in order to calculate the thermal load of each system element. The reactor temperature changes were determined by modeling the feed mixing tank capacity, heat exchange, and heat storage tank. An analysis was carried out to confirm the condition of the feed mixing tank, heat exchanger, heat storage tank capacity as well as the operating conditions of the system so as to maintain the target reactor temperature.

• 설비공학논문집
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• 제21권6호
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• pp.355-366
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• 2009

In the present study, fuel cell driven ground source heat pump system is applied to a large community building and performance of the heat pump system is computationally analyzed. Conduction heat transfer between brine pipe and ground is analyzed by TEACH code to predict the performance of heat pump system. Predicted COP of the heat pump system and the energy cost were compared with variation of the location of the objective building the water saturation rate of soil and the driven powers of heat pump system. Significant reduction of energy cost can be accomplished by employing the fuel cell driven heat pump system in comparison with the late-night electricity driven system. It is due to the low electricity production cost of fuel cell system and the application of recovered waste heat generated during electricity production process to the heating of large community building.

• Current Research on Agriculture and Life Sciences
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• 제31권1호
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• pp.25-29
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• 2013

As a specialty oil, furan fatty acids have gained special attentions since they are known to play important roles in biological systems including human. Although several studies reported chemical synthesis of furan fatty acids, their synthesis consisted of complicated chemical multistep with chemical catalysts. Recently, a simple one-step heat treatment method was developed to produce a novel furan fatty acid, 7,10-epoxy-octadeca-7,9-dienoic acid (7,10-EODA) from a dihydroxyl fatty acid 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). In this report we studied about optimization of environmental conditions for the maximum production of 7,10-EODA from DOD by heat treatment. Production of 7,10-EODA was maximized at over $85^{\circ}C$ for at least over 48 hour in hexane. Solvent volume for maximum production should be over 300 mL per 10 mg DOD.

• 열처리공학회지
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• 제20권5호
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• pp.273-285
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• 2007

• Asian-Australasian Journal of Animal Sciences
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• 제6권2호
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• pp.271-274
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• 1993

Four Holstein heifers were used in the present study to investigate the effect of standing and lying behaviors on heat production and physiological responses under low (L), medium (M) and high (H) levels of TDN intake. Rectal temperature (RT), respiration rate (RR), heart rate (HR), heat production (HP) and animals behavior (standing time, ST) were measured continuously for 5h (11:00-16:00) periods. There was a tendency for increased RT with TDN intake, and no difference in RT was observed between standing and lying. The RR, HR and HP during standing were significantly higher (p<0.05) than during lying. The difference between standing and lying HP were 4.41, 4.68 and $5.37kJ/kg^{0.75}$ h for L, M and H of TDN intake, respectively. These values showed that standing HP was 18.6-20.9% higher than lying HP. A multiple regression analysis of HP ($kJ/kg^{0.75}$ h) on TDN intake ($g/kg^{0.75}$ d) and ST (min/h) was HP = 7.75 + 0.28 TDN intake + 0.12 ST (R = 0.84). This analysis showed that the total HP not only depend on feed intake levels, but also depends on animal behavior. It was suggested that the change in HP due to the change in feed intake and animal behavior would influence the level of heat loss which was indicated by the changes in the RR and HR.

• 한국축산시설환경학회지
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• 제20권4호
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• pp.147-154
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• 2014

Heat stress is a significant burden to animal production in most areas of the world. Improving our knowledge of physiological and metabolic mechanisms of acclimation may contribute to the development of procedures that may help to maintain health and production efficiency under hot temperature. The effect of Ulmus pumila (UP) extract in inducing Heat Shock Proteins (HSPs) expression in heat-stressed RAW264.7 macrophage cells was investigated. Cell viability assay showed a dose dependent increase in cells after treatment with UP for 24 hours. RT-PCR and western blot analysis showed that increasing concentrations of UP induce the expression of Heat Shock Factor 1 (HSF1) and dose dependently upregulated the expression of Heat shock protein 70 (Hsp70) and Hsp90. LPS-induced nitric oxide was dose-dependently reduced while phagocytic activity greatly recovered with UP treatment. These data demonstrated that UP can be a potential candidate in the development of cytoprotective agent against heat stress.

• 대한기계학회논문집A
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• 제32권12호
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• pp.1140-1145
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• 2008

In conventional cutting system of Heat-Shrink-Tube, workers operate cutting system after considering about length and quantity of heat-shrink-tube. So, not only work time and production cost is increased but also material is wasted because the data that workers have to consider is so much. In this paper, an effective cutting system of heat-shrink-tube was developed to reduce production cost, work time and waste of material. The cutting system consists of a supervisory computer installed inside a control room, a on-site computer installed on the work area, and a PLC system. In the developed system, a supervisory computer send work order to the on-site computer using LAN and the on-site computer operates the cutting system of the heatshrink-tube after it makes an array production order. Also, the on-site computer reports information to the supervisory computer when an accident happened.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.197-208
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• 2023

The objective of this study was to investigate the effects of a traditional dry period (60 d) versus a no dry period (0 d) on the milk production, physiological response, and metabolic status of dairy cows exposed to heat stress during the transition period. Holstein dairy cows (n = 15) with similar expected calving dates were randomly assigned to two different dry period lengths: (1) no dry period (n = 7) and (2) a traditional dry period of 60 days (n = 8). All cows were studied from 8 weeks before expected calving to 10 weeks after calving and experienced heat stress during the transition period. The results showed that cows with no dry period decreased their milk yield in subsequent lactation, but compensated for the loss of milk yield accounted for by additional milk yield before calving. The energy balance at postpartum was improved in cows with no dry period compared to cows with a traditional dry period. There were no significant differences in the physiological response and blood metabolites at postpartum between the dry period lengths of dairy cows exposed to heat stress during the transition period. Taken together, our results showed that omitting the dry period improved the milk production and metabolic status of dairy cows exposed to heat stress during the transition period.

• Nuclear Engineering and Technology
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• 제47권4호
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• pp.424-433
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• 2015

The operating characteristics of hydrogen iodide (HI) decomposition for hydrogen production were investigated using the commercial computational fluid dynamics code, and various factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare device performance with that expected for device development. Hydrogen production increased with an increase of the surface-to-volume (STV) ratio. With an increase of hydrogen production, the reaction heat increased. The internal pressure and velocity of the HI decomposer were estimated through pressure drop and reducing velocity from the preheating zone. The mass of $H_2O$ was independent of the STV ratio, whereas that of HI decreased with increasing STV ratio.