• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.233-236
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• 2006

This study presents a technique to quantitatively measure the corrosion level of a reinforcing bar using the infrared thermography system. The temperature-distribution of the concrete surface is monitored and the temperature change of the reinforcing bar is analysed in terms of corrosion level and concrete cover depth. The experimental results indicate that temperature increase of the reinforcing bar is significant when the corrosion level is high, which implies that the quantity of heat is strongly dependent on corrosion level. Also, as the concrete cover depth of the specimen and the atmosphere temperature increase, the temperature variation becomes small.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.185-192
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• 2022

A compacted bentonite buffer is a major component of engineered barrier systems, which are designed for the disposal of high-level radioactive waste. In most countries, the target temperature required to maintain safe functioning is below 100℃. If the target temperature of the compacted bentonite buffer can be increased above 100℃, the disposal area can be dramatically reduced. To increase the target temperature of the buffer, it is necessary to investigate its properties at temperatures above 100℃. Although some studies have investigated thermal-hydraulic properties above 100℃, few have evaluated the water suction of compacted bentonite. This study addresses that knowledge gap by evaluating the water suction variation for compacted Korean bentonite in the 25-150℃ range, with initial saturations of 0 and 0.22 under constant saturation conditions. We found that water suction decreased by 5-20% for a temperature increase of 100-150℃.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.5
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• pp.715-724
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• 2022

In many electric vehicles, large-capacity pouch-type lithium-ion battery packs are mainly used to increase the mileage on a single charge. The lithium ion battery should be operated within the temperature range of 25℃ to 40℃ because the battery performance can be rapidly deteriorated due to an increase in internal temperature. Battery thermal management system (BTMS) can give the suitable temperature conditions to battery by water cooling method. In this research, the heat transfer characteristics (the battery temperature distributions and the water flow characteristics) were analyzed by CFD method to investigate the thermal performance of the cooling plate with 4-pass water flow structure. Moreover, the effect of the presence of fins between the battery cell was identified. The fins made smooth temperature distributions between the battery cells due to the heat spreading and lower the average battery cells temperature.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.5
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• pp.833-838
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• 2008

Generally Lighting system consists of lamp and luminaire. When a fluorescent lamp is installed in luminaire, power and light output is changed by ambient temperature. Particularly electrodeless lamp depends on the changes that are mercury pressure with amalgam temperature and magnetic properties with ferrite temperature. It has finally influence on optical efficiency. In this study, the temperature change of ferrite and cold spot, vessel are measured at transitional state and then same characteristics are measured with increase of ambient temperature. At transitional state, luminous flux is related to temperature change of cold spot that compare with behavior of mercury pressure and light output. At increase of ambient temperature, we analyzed change that efficiency and electrical, optical characteristics of elecrodeless lamp are related to ferrite core and cold spot temperature. Additionally, spectrum, color temperature and coordination are measured to check that is relation with ambient temperature.

• Journal of the Korean Institute of Gas
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• v.14 no.3
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• pp.21-25
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• 2010

An objective of this study is to develop a polyurethane foam(PUF) maintaining its mechanical strength at room temperature as well as at extremely low temperature. The effect of temperature on the physical properties of PUF with the increase in polyol functionality was investigated. At room and cryogenic temperature, compressive strengths of the PUFs increased up to 70% and 30% with an increase in polyol functionality, respectively. At room temperature tensile strength of PUFs tends to increase as functionality of polyol increases, however, the strength at $-190^{\circ}C$ shows different tendency. Compressive strength of PUF is higher in cryogenic temperature than in room temperature. However, as the number of polyol functionality become more than 4, tensile strength of PUF is lower in cryogenic temperature than in room temperature.

• Polymer(Korea)
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• v.26 no.6
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• pp.812-820
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• 2002

The positive temperature coefficient (PTC) characteristics of polymer composites were investigated with the nano-sized carbon black particles using solution tasting and melt compounding methods. The polymeric PTC composites should the electrical threshold at 35 wt% for the melt compounding method and 40 wt% for the solution casting method. The ethylene vinylacetate copolymer (EVA) composite showed a gradual increase of resistance as a function of temperature and showed a maximum at the polymer molting point. The resistance of the high-density polythylene (HDPE) composite remains unchanged with temperature but started to Increase sharply near the melting point of HDPE and showed a maximum resistance at the melting point of HDPE. The dispersion of nano-sized carbon black particles was investigated by scanning electron microscopy (SEM) and low resistance after electrical threshold, and both methods exhibited a well dispersed morphology. When the electric current was applied to the PTC composites, the resistance started increasing at the curie temperature and further increased until the trip temperature was roached. Then the resistance remained stable over the trip temperature. The secondary increase started at T$\sub$m/ of matrix polymer and kept increasing up to the trip temperature.

• Journal of Acupuncture Research
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• v.30 no.1
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• pp.71-80
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• 2013

Objectives : This study aimed to investigate the difference of abdominal skin temperature responses following moxibustion comparing stimulation method. Methods : Moxibustion was applied on the acupuncture points of $CV_4$, $CV_6$, $CV_{12}$. Thirty healthy men were randomly divided into two groups, one receiving a single moxibustion stimulation in three locations '$CV_4{\cdot}CV_6{\cdot}CV_{12}$'(n=15) and the other receiving triple moxibustion stimulations in one location '$CV_{12}$'(n=15) for 30 min. To obtain the skin temperature on abdominal region, a thermograph was used. Three arbitrary frames(the upper abdominal, lower abdominal, whole abdominal regions) were made to analyse skin temperature. Thermographic images were obtained at before and after the procedure of indirect moxibustion and 5, 10, 15, 20, 25, 30 min afterwards. Results : An increase in skin temperature on the three abdominal regions was observed following both one point and three points moxibustion administrations. Significant increase in skin temperature of the whole abdominal region was observed at 30 min after the procedure of three points moxibustion compared with one point moxibustion stimulation. A tendency of skin temperature changes over time was observed. Conclusions : In this study, skin temperature of lower abdominal region does not increase after triple moxibustion stimulations on $CV_{12}$. Administration of single moxibustion on $CV_4$, $CV_6$, $CV_{12}$ makes greater changes in skin temperature on the whole abdominal region than triple moxibustion on $CV_{12}$.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.523-538
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• 2011

This study analyzes the changes in the surface area of each forest cover, based on temperature data analysis and satellite imagery as the basic methods for the impact assessment of climate change on regional units. Furthermore, future changes in the forest cover are predicted using the double exponential smoothing method. The results of the study have shown an overall increase in annual mean temperature in the studied region since 1990, and an especially increased rate in winter and autumn compared to other seasons. The multi-temporal analysis of the changes in the forest cover using satellite images showed a large decrease of coniferous forests, and a continual increase in deciduous forests and mixed forests. Such changes are attributed to the increase in annual mean temperature of the studied regions. The analysis of changes in the surface area of each forest cover using the statistical data displayed similar tendencies as that of the forest cover categorizing results from the satellite images. Accordingly, rapid changes in forest cover following the increase of temperature in the studied regions could be expected. The results of the study of the forest cover surface using the double exponential smoothing method predict a continual decrease in coniferous forests until 2050. On the contrary, deciduous forests and mixed forests are predicted to show continually increasing tendencies. Deciduous forests have been predicted to increase the most in the future. With these results, the data on forest cover can be usefully applied as the main index for climate change. Further qualitative results are expected to be deduced from these data in the future, compared to the analyses of the relationship between tree species of forest and climate factors.

• Tunnel and Underground Space
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• v.2 no.2
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• pp.224-236
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• 1992

It is very important to determine the thermo-mechanical characteristics of the rock mass surrounding the repository of radioctive waste and the LPG storage cavern. In this study, Hwasoon-Shist. Dado-Tuff adn Chunan-Tonalite were the selected rock types. Temperature dependence of the mechanical properteis such as uniaxial compressive strength, tensile strength, Young's modulus was investigated by measuring the behaviour of these properties due to the variation of temperature. Also, the characteristics of strength and deformation of these rocks were examined through high-temperature triaxial compression tests with varing temperatures and confining pressures. Important results obtained are as follows: In high temperature tests, the uniaxial compressive strength and Yong's modulus of Tonalite showed a sligth increase at a temperature up to 300$^{\circ}C$ and a sharp decrease beyond 300$^{\circ}C$, and the tensile strength showed a linear decrease with increasing heating-temperature. In high-temperature triaxial compression test, both the failure stress and Young's modulus of Tonalite increased with the increase of confining pressure at constant heating-temperature, and the failure stress decreased at 100$^{\circ}C$ but increased at 200$^{\circ}C$ under a constant confining pressure. In low temperature tests, the uniaxial compressive and tensile strengths and Young's modulus of these rocks increased as the cooling-temperature is reduced. Also, the uniaxial compressive and tensile strengths of wet rock specimens are less than those of dry rock specimens.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.167-168
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• 2017

With the recent increase in demand for construction there has been an increase in the use of the raw material cement when mixing concrete; managing quality of cement powder, therefore, is most important. Therefore this study sought at first to develop a rapid appraisal using the Hydrometer method researched previously, for it was thought that when suspending cement in a solution and applying the Hydrometer method to it the temperature changes in the solution would have a great effect on the density value of the Hydrometer method; yet there has been no report of such influence factors. Therefore after analyzing the influence factors that the type of suspending solution and changes in temperature could have on rapid appraisal of fineness, using the Hydrometer method, this study was able to determine that using water at 20℃ was the most appropriate, and with every temperature increase of 10℃ the value of fineness should also be increased above or below 7% as well.