• Nuclear Engineering and Technology
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• 제52권11호
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• pp.2620-2629
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• 2020

As an early stage in the development of a water calorimeter, this study established a computer simulation methodology for analyzing the thermal behavior of a water calorimeter based on radiation transport and energy deposition. As a result, this study developed a method wherein the energy deposition distribution, which is obtained by applying Monte Carlo methods in water calorimeters, is directly used as a heat source for the thermal analysis model. Based on the proposed method, heat transfer in a water vessel and the effect of thermistor self-heating were analyzed. Through an analysis of the water velocities with and without a water vessel, it was found that a water vessel can serve as a convection barrier. Furthermore, it was confirmed that when considering thermistor self-heating, the water temperature change at the thermistor location is 0.219 mK higher compared to that when the thermistor was not considered. Therefore, thermistor self-heating must be considered to analyze the thermal behavior of a water calorimeter more accurately.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.47-48
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• 2017

The substrate behavior response testing outlined in KS F 2622 evaluates the leakage cause of waterproofing membrane systems when subjected to the concrete joint load behaviors by removing the waterproofing layer after testing, relying mostly on visual observation and subjective analysis. A non-destructive leakage cause and failure type analysis method is proposed currently in this study by the means of detecting leakage paths using thermal emission imaging systems. Test specimens are placed in varying temperature conditions after the concrete joint movement testing and are scanned using the thermal emission camera to determine the location and dimension of the adhesion failure/leakage path beneath the waterproofing membranes.

• 폴리머
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• 제29권5호
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• pp.508-517
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• 2005

가전제품용 플라스틱 재료의 열화 거동과 신뢰성을 고찰하기 위해 열분해에 따른 동역학적 매개변수를 결정하기 위하여 동역학적 열중량 분석기법을 사용하였고, 촉진 열화시험을 수행하였다. 또한, 플라스틱 재료의 내후성을 고찰하고자 제논 아크 광원을 사용하여 촉진 열화시험을 하였고, 가속 열화시험후 시료의 색차를 컬러 아이 3010 색차분석기를 이용하여 측정하였다. 재료는 중량감소율이 증가함에 따라 열분해 활성화 에너지도 증가하는 경향을 보였다. 플라스틱 재료의 열분해에 관한 기술은 Kim-Park법이 가장 효과적인 분석법으로 나타났다. 플라스틱 재료는 빠른 열화를 진행시키는 자외선에 아주 민감하게 반응하였다.

• 한국의류산업학회지
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• 제20권6호
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• pp.744-751
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• 2018

This study aimed to provide the information on the thermal sensation and the amount of clothing worn of junior high school students in winter classroom the relation with their climate adaptability. Total usable questionnaires were obtained from 467 male and female students. The questionnaire included general characteristics, physical characteristics, self awareness of body shape, climate adaptability and subjective thermal sensation in winter classroom. The data were analyzed using SPSS Statistics 18.0 for frequency analysis, factor analysis, chi-square analysis, t-test and correlation analysis. The results were as follows. The average body type based on BMI was normal($20.1kg/m^2$ ). Females perceived their body type as thinner than males. They wore more (8.67 garment items compared to 8.14 for males). Only about 25% of students voted the thermal sensation to neutral(47% cool~very cold, 28% warm~very hot). Females were more sensitive to the cold, perceived less healthy, and wore more garments in the cold. Students felt colder in winter classroom when their cold adaptability was lower and they actively adjusted thermal insulation against the cold. It is recommended to suggest the guidelines for the proper indoor temperature and for the wear behavior in classroom in the perspectives of increasing the learning efficiency and improving the students' climate adaptability.

• 동력기계공학회지
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• 제18권3호
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• pp.87-92
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• 2014

This study is aimed at investigating the thermal behavior of immersion-cooled high power LED lighting engines. 3D CFD models have been generated for the numerical analysis. Five cases in terms of the configuration of LED chips have been explored for various passive cooling conditions of the lighting engine, i.e., the natural air convection with a lens, the natural air convection without a lens, the deionized water-immersion cooling condition with a lens. The numerical study reveals that the deionized water-immersion cooled lighting engine has nearly twice better thermal performance than the natural air convection cooled lighting engine containing a lens. The investigation has also demonstrated that the four chips configuration has the better thermal performance than the single chip configuration.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.585-590
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• 2004

An analytical method is proposed for the analysis of the reinforced concrete flexural beam subjected to high temperature. The analysis procedure for the material properties, in this study, is subdivided into two types; thermal properties for temperature distribution analysis and mechanical properties for structural analysis. Using F.D.M. and segmentation method, the program was made to predict the thermal behavior of RC beams during heating. In previous studies, the structural behavior of fire damaged RC beams was investigated though experiments. Comparing the result by program to the one by experiment, the comparison indicated that the proposed segmentation method for the thermal respose analysis present fairly a good agreement with experiment.

• Steel and Composite Structures
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• 제25권3호
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• pp.315-326
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• 2017

In this work, thermoelastic dynamic behavior of functionally graded carbon nanotube reinforced composite (FG-CNTRC) cylinders subjected to mechanical pressure loads, uniform temperature environment or thermal gradient loads is investigated by a mesh-free method. The material properties and thermal stress wave propagation of the nanocomposite cylinders are derived after solving of the transient thermal equation and obtaining of the time history of temperature field of the cylinders. The nanocomposite cylinders are made of a polymer matrix and wavy single-walled carbon nanotubes (SWCNTs). The volume fraction of carbon nanotubes (CNTs) are assumed variable along the radial direction of the axisymmetric cylinder. Also, material properties of the polymer and CNT are assumed temperature-dependent and mechanical properties of the nanocomposite are estimated by a micro mechanical model in volume fraction form. In the mesh-free analysis, moving least squares shape functions are used to approximate temperature and displacement fields in the weak form of motion equation and transient thermal equation, respectively. Also, transformation method is used to impose their essential boundary conditions. Effects of waviness, volume fraction and distribution pattern of CNT, temperature of environment and direction of thermal gradient loads are investigated on the thermoelastic dynamic behavior of FG-CNTRC cylinders.

• Journal of the Korean Wood Science and Technology
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• 제34권5호
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• pp.59-66
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• 2006

The thermal properties of wood flour, Hwangto, and maleated polyethylene (MAPE) reinforced HDPE composites were investigated in this study. The thermal behavior of reinforced wood polymer composites was characterized by means of thermogravimetric (TGA) and differential scanning calorimetric (DSC) analyses. Hwangto and MAPE were used as an inorganic filler and a coupling agent, respectively. According to TGA analysis, the increase of wood flour level increased the thermal degradation of composites in the early stage, but decreased in the late stage. On the other hand, Hwangto reinforced composites showed the higher thermal stability than virgin HDPE, from the determination of differential peak temperature ($DT_p$). Decomposition temperature of wood flour and/or Hwangto reinforced composites increased with increase of heating rate. From DSC analysis, melting temperature of reinforced composites little bit increased with the addition of wood flour or Hwangto. As the loading of wood flour or Hwangto to HDPE increased, overall enthalpy decreased. It showed that wood flour and Hwangto absorbed more heat energy for melting the reinforced composites. Hwangto reinforced composites required more heat energy than wood flour reinforced composites and virgin HDPE. Coupling agent gave no significant effect on the thermal properties of composites. Thermal analyses indicate that composites with Hwangto are more thermally stable than those without Hwangto.

• 한국공작기계학회논문집
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• 제10권4호
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• pp.104-110
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• 2001

The objective of this study is structural analysis of continuous casting mold. A two-dimensional finite element model was developed to compute the temperature distribution, thermal stress and thermal strain behavior for continuous casting mold. Structural analysis was made using thermal analysis result, utilizing transient analysis of ANSYS. This structural analysis results, many variables such as casting speed, cooling condition film coefficient, convection and load condition are considered.

• 한국재료학회지
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• 제19권12호
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• pp.686-691
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• 2009

The effects of thermal properties on the crystallization behavior of $CaMgSi_2O_6$ glass-ceramics were investigated as a function of sintering temperature from 800$^{\circ}C$ to 900$^{\circ}C$. The crystallization behavior of the specimens depended on the sintering temperature, which could be evaluated from the differential thermal analysis, X-ray diffraction and Fourier transform infrared spectroscopy. With increasing sintering temperature, the thermal conductivity of the sintered specimens increased, while the coefficient of thermal expansion (CTE) of the sintered specimens decreased. These results could be attributed to the increase of crystallization, confirmed from the estimation by density measurements. Also, the thermal diffusivity and specific heat capacity of the sintered specimens were discussed with relation to the sintering temperature. Typically, a thermal conductivity of 3.084 $W/m^{\circ}C$, CTE of 8.049 $ppm/^{\circ}C$, thermal diffusivity of 1.389 $mm^2/s$ and specific heat capacity of 0.752 $J/g^{\circ}C$ were obtained for $CaMgSi_2O_6$ specimens sintered at 900$^{\circ}C$ for 5 h.