• 한국축산식품학회지
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• 제34권1호
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• pp.20-25
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• 2014

This study evaluated the effects of frankfurter fat content on Listeria monocytogenes resistance to heat stress and gastric fluid, and the Caco-2 cell invasion efficiency of the pathogen. A 10-strain mixture of L. monocytogenes was inoculated on frankfurters formulated with 10%, 20%, and 30% fat content (10%: F10, 20%: F20, 30%: F30) and stored at $10^{\circ}C$ for 30 d. The samples were analyzed for L. monocytogenes resistance to heat stress and a simulated gastric fluid challenge. The total bacteria and L. monocytogenes survival rates were measured on tryptic soy agar plus 0.6% yeast extract and Palcam agar, respectively. L. monocytogenes colonies inoculated on F10, F20, and F30 samples were used for a Caco-2 cell invasion assay. In general, no obvious differences were observed between the survival rates of total bacteria and L. monocytogenes grown on different fat contents under heat stress and gastric fluid challenge. However, L. monocytogenes obtained from the F30 samples had a significantly higher Caco-2 cell invasion efficiency than those in the F10 and F20 samples (p<0.05). These results indicate that although high fat content in food may not be related to L. monocytogenes resistance to heat stress and gastric fluid, it may increase the Caco-2 cell invasion efficiency of the pathogen.

• 열처리공학회지
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• 제16권5호
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• pp.260-266
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• 2003

In order to study the interfacial reaction between Nb thin sheet and Fe-C-(Si) alloy with different Chemical compositions, they were cast-bonded. The growth of carbide layer formed at the interface after isothermal heat treatment at 1173K, 1223K, 1273K and 1323K for various times was investigated. The carbide formed at the interface was NbC and the thickness of NbC layer was increased linearly in proportional to the heat treating time. Therefore, It was found that the growth of NbC layer was controlled by the interfacial reaction. The growth rate constant of NbC layer was slightly increased with increase of carbon content when the silicon content is similar in the cast irons. However, as silicon content increases with no great difference in carbon content, the growth of NbC layer was greatly retarded. The calculated activation energy for the growth of NbC layer was varied in the range of 447.4~549.3 kJ/moI with the compositions of cast irons.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.228-228
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• 2017

Rice production and quality could be changed by temperature condition. Extremely high temperature event have been occurred more frequently for global warming. To increase rice quality against to global warming, breeding of heat tolerance rice cultivar is needed. Ilmi which is the one of Korean leading rice cultivar shows heat stress resistant character during ripening stage. Yield and quality (brown and milled rice) of Ilmi did not show significant different under high temperature condition compared to control condition. However, the main physiological characters for heat resistance of Ilmi have been not investigated yet. Therefore we try to investigate the heat tolerance characters of Ilmi. Two rice cultivars, Ilmi and Ilpum-which is heat susceptible rice cultivar, were cultivated under natural condition in wagnor pot until heading was appeared. After checking heading date, each material was cultivated under different temperature condition, heat($32/22^{\circ}C$) and control($26/16^{\circ}C$) condition. Anti-oxidant enzyme activity was checked during ripening stage in each material. Catalase and ascorbic peroxidase activity of leaf under heat stress condition were higher in Ilmi than Ilpum especially early ripening stage. Analyzing of stress resistance using $H_2O_2$, the flag leaf of Ilmi showed more green color than Ilpum with higher chlorophyll content than those of Ilpum. We also checked the amount of $H_2O_2$ content in young leaf of each material by treating high temperature. $H_2O_2$ content in each material was increased according to treatment time. However $H_2O_2$ content of young leaf in Ilmi was less than those in Ilpum. Also catalase and ascorbic peroxidase activity in leaf increased much faster in Ilmi than Ilpum. With those data, we confirmed that heat stress resistance of Ilmi is due to the higher anti-oxidant activity against to stress condition. We will investigate the heat tolerance characters of Ilmi more in further study to enhance the breeding effect of heat stress tolerance rice.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.21-30
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• 1998

A theoretical model was developed to evaluate the effects of soil and airflow characteristics on the soil-air heat exchanger performances. The model, which includes three-dimensional transient energy and mass equilibrium-equation, was solved by using a computer program that uses Finite Difference Methods and Gauss-Seidel iteration computation. Energy gains, heat exchange efficiencies, and outlet air temperature are presented including the effects of soil moisture content, soil conductivity, soil thermal diffusivity, and soil initial temperature. Also, data related to the effects of airflow rate and inlet air temperature on the thermal performance of the system are presented. The results indicated that energy gains depend on soil conductivity, soil thermal diffusivity, and soil initial temperature. Heat exchange efficiencies relied on air mass flow rate and soil moisture content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.409-414
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• 2001

The hydration of cement paste occurs when the cement is mixed with water. During the hydration, hydration heat causes the thermal stress depending on the size of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study, conduction calorimeter and concrete insulation hydration heat meter were used to investigate the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment.

• Journal of the Korean Wood Science and Technology
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• 제23권4호
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• pp.67-73
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• 1995

This study was undertaken to investigate the effect of heat treatment on the dynamic viscoelasticity of three species of Phyllostachys bambusoides, Phyllostachys nigra var. henonis and Phyllostachys pubescens, grown in southern Korea. The bamboo was treated for 3~24 hours at $60{\sim}180^{\circ}C$, and then was treated in a climatic chamber for 3~48 hours at $40^{\circ}C$ and 95% relative humidity. The results obtained are summarized as follows : 1. Dynamic Young's modulus decreased with increasing temperature and duration of the heat treatment. 2. Internal friction decreased with increasing treatment duration. 3. Moisture absorption decreased with increasing temperature and duration of the heat treatment. 4. Dynamic viscoelasticity decreased, whereas internal friction slowly increased, with increasing moisture content.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.341-346
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• 2002

This study is intended to check the possibility to estimate water content by heat-drying method with variation of W/C and slump. According to the results, in case of electric range method, when water content is less than 165kg/m$^3$ in mixture, it is estimated more and in more than 165kg/m$^3$, it is estimated less. It shows that water content in gas burner method is estimated less by about 2kg/m$^3$. Also, estimated water content shows difference by less than 12kg/m$^3$ in electric range method and by less than 12kg/m$^3$ in gas burner method. Therefore, it is thinked that if tested without error from preparing a sample to calculating amount of water, water content will be estimated exactly in the construction field.

• 한국식품영양학회지
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• 제33권2호
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• pp.117-130
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• 2020

The purpose of this study was to compare differences in the main food components of quinoa (Chenopodium quinoa Willd.) cultivated in Hongcheon after steaming, boiling, and roasting. Among the general components, crude protein, fat, and ash content were the highest in raw quinoa. Dry matter and carbohydrate content was the highest in steamed quinoa, while total dietary fiber content was highest in roasted quinoa. Total amino acid contents were the highest in boiled quinoa and lowest in steamed quinoa. Fatty acid content was highest in raw quinoa and lowest in boiled quinoa. The mineral (calcium, potassium, and phosphorus) and vitamin content was most enriched in raw quinoa, while iron, magnesium, zinc, and manganese were highest in boiled quinoa. For free sugars, the fructose and sucrose levels were highest in raw quinoa, while glucose level was highest in roasted quinoa. The water-soluble vitamin and free sugar contents were lowest in boiled quinoa. In summary, nutritional levels of vitamins vulnerable to heat and unsaturated fatty acids decreased after cooking with heat, while those of amino acids and saturated fatty acids increased after cooking with heat, although there were variables based on different cooking methods.

• 한국세라믹학회지
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• 제25권5호
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• pp.502-508
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• 1988

The $\alpha$ to $\beta$ phase transformation of $\alpha$-Si3N4 whisker and related microstructural changes have been investigated. When only $\alpha$-Si3N4 whisker was heat treated in the range 1650~175$0^{\circ}C$, the $\alpha$ to $\beta$ phase transformation occured. In this case, it eas suggested that the oxygen content in $\alpha$-Si3N4 whisker affected the transformation behavior. Although $\alpha$-Si3N4 whisker with Si was heat treated under the same condition, however, the variation of $\beta$- fraction had a similar tendency with heat treating time. Therfore, it was considered that the oxygen content in $\alpha$-Si3N4 whisker affected the transformation behavior dominently rather than the content of added Si. The added $\beta$ phase did not affect the transformation behaviro of $\alpha$-Si3N4 whisker.

• Nuclear Engineering and Technology
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• 제31권3호
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• pp.294-302
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• 1999

The influence of source term release parameters on offsite health effects was examined for the YGN 3&4 nuclear power plants. The release parameters considered in this study are release height, heat content, and release time. The effects of core inventory change as a function of fuel burnup was also examined. The health effects by the change of release parameters are early fatalities, cancer fatalities, and early fatality distance. The results showed that early fatalities and early fatality distance decrease as release height increases, although it does not have significant influence on cancer fatalities. The values of both early and late health effects decrease as heat content increases. As release time increases, health consequence shows maximum value in 2 hours of release time and then decreases rapidly. As fuel burnup increases, early fatalities decrease rapidly, while cancer fatalities increase rapidly. Both cases show little variation afterward. Early fatality distance is almost same in all fuel turnup history. The information obtained through this research is very useful in developing strategies for reducing offsite consequences when combined with the influence of weather conditions on offsite risks.