• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.469-472
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• 2005

With all ensuring the fire resistance structure as a method of setting the required cover thickness to fire, the RC is significantly affected from the standpoint of its structural stability that the compressive strength and elastic modulus is reduced by fire. Normally, the degradation of concrete member exposed to fire is largely dependent on the fire scale and fire condition. There is therefore a need to precisely predict the deterioration and fire damage of the exposed member. Thus, this work estimated the temperature distribution inside a member taking into consideration of the thermal properties by means of finite element method(FEM). The estimation results in a little higher prediction value than the experimental value in surface layer and is almost coincident with the experiment as the heating depth increase. From this work it can be known that the simulation application of FEM using the thermal properties of concrete member in high temperature gives rise to the confident prediction in the prediction of temperature distribution.

• 대한건축학회논문집:구조계
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• 제34권7호
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• pp.35-42
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• 2018

Semi-transparent Photovoltaics (STPV) works as an exterior material replacing windows as well as functioning as a electricity generator. As a result, it also affects the building's heating, cooling and lighting loads. In this study, we used the concept of Net Electricity Benefit(NEB) to conduct a parametric analysis of building energy impact of STPV. The NEB of STPV is from $-1kWh/m^2$ to $6kWh/m^2$. Since NEB represents the amount of energy increase or decrease when STPV is applied compared to the standard window, a value of 0 or less means that the demand for building energy can be increased rather than applying a general window having high thermal performance and high visible light transmittance value. Therefore, it is necessary to perform a comprehensive performance evaluation considering both the performance evaluation based on the existing power generation performance and the influence on the building energy.

• 한국건축시공학회지
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• 제22권5호
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• pp.425-430
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• 2022

초고층 건축물용 매트기초에 사용되는 콘크리트는 시공성 및 품질확보를 위하여 일체타설로 진행되는 경우가 많다. 하지만 일체타설의 경우 수화반응 과정에서 온도균열이 발행할 우려가 높으며 혼화재 치환을 통해 고성능 고내구성 콘크리트 최적배합을 도출할 필요가 있다. 본 연구에서는 저자의 기존연구에서 도출한 최적 고성능 저발열 콘크리트 배합으로 제작된 시험체를 대상으로 염해 및 탄산화, 내황산염에 대한 실험을 실시하고 염소이온 확산계수와 탄산화계수, 황산염에 대한 시멘트 매트릭스의 저항을 정량적으로 평가하였다. 혼화재의 혼입에 의한 잠재수경성 및 포졸란 반응에 의한 높은 저항성을 확인할 수 있었다.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 추계학술논문발표회 논문집
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• pp.484-489
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• 2008

We carried out a one-way heating experiment on the PC panel manufactured by changing the filling depths(20,30,40,50mm) of concrete regarding the fire strength in order to measure the inner concrete pressure which is a direct cause of concrete spalling. This fire experiment was conducted under the fire strength conditions of ISO 834 Standard, Modified Hydrocarbon and the maximum value of Pore Pressure was measured. As a result of analyzing the time it took to reach maximum pressure, it showed that the time rising to the maximum pressure of high strength concrete of 40MPa is slower than that of a 24MPa tunnel lining. In case of ISO fire conditions, spalling damage might take place in heating period of $20{\sim}40$ minutes in the range of $100{\sim}200^{\circ}C$ temperature. In case of MHC fire conditions, the area damaged by fire can appear after a lapse of $25{\sim}50$ minutes in the range of $150{\sim}250^{\circ}C$ temperature.

• 산업기술연구
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• 제36권
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• pp.77-81
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• 2016

Superparamagnetic $Fe_3O_4$ nanoparticles with particle size from 10 to 20 nm were synthesized by coprecipitation method. Subsequently, the $Fe_3O_4$ nanoparticles were used to fabricate $Fe_3O_4/SiO_2$ core-shell nanoparticles by sol-gel method. The $Fe_3O_4/SiO_2$ nanoparticles synthesized by sol-gel method exhibit the high uniformities of particle size and shape. We also investigated the heating characteristics of $Fe_3O_4$ and $Fe_3O_4/SiO_2$ nanoparticles for biomedical applications. The $Fe_3O_4$ nanoparticles show the faster temperature increase and the higher specific loss power(SLP) value than the $Fe_3O_4/SiO_2$ nanoparticles.

• 환경위생공학
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• 제15권4호
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• pp.123-133
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• 2000

The kinetic analysis was carried out for commercial rubbers such as NR, IR, BR, SBR 1500, and SBR 1700. Kinetic analysis for the commercial rubbers was performed using the thermogravimetric method, with which the activation energies of NR obtained by Kissinger, Friedman, and Ozawa's method were 195.0, 198.3 and 186.3kJ/mol, whereas that of SBR 1500 were 246.4, 247.5 and 254.8kJ/mol, respectively. It was shown that the yield of pyrolytic oil was generally increased with final temperature increasing, yet slightly decreased or increased over $700^{\circ}C$. Considering the effect of heating rate, it was found that the yield of pyrolytic oil was not consistent for each sample. The number average molecular weight of SBR 1500 was in the range of 740~2486. The calorific value of SBR 1500 was 39~40kJ/g, which were made comparative study of the conventional fuel such as kerosene, diesel, light fuel, and heavy fuel. Therefore it was essential that the selection of the suitable kinetic model and the mathematical solution because of the difference in parameters obtained from each method. It was proposed that the range of $600~700^{\circ}C$ in final temperature and high heating rate due to short run time. It was suggested that the pyrolytic oil be available to use to the fuel.

• 한국농촌건축학회논문집
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• 제16권1호
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• pp.17-26
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• 2014

This study examined the trend of floor space characteristics, size characteristics and modeling characteristics so as to evaluate the satisfactory level of subjects living in Hanok. By doing so, the type of Hanok was classified into 5 groups. The satisfactory level was evaluated after the subjects resided in Hanok based on each type of housing. In the satisfactory level investigation, which was conducted after the residence, the overall satisfactory level on Hanok showed to be high. In the evaluation on the residence scale, positive results were generally achieved regarding 'full size of residence', 'number of rooms compared to residence size', 'size of living room', etc. The indoor environment of residence evaluation mainly showed positive results regarding 'ventilation', but most subjects were unsatisfied in regard to 'heating', 'noise', 'lighting', etc. In the behavioral factor evaluation of residents, positive results were gained regarding 'health', but comparatively negative results showed based on items of 'construction expense', 'burden of maintenance expense', 'investment value', etc. After analyzing the influential factors on the overall satisfactory level, results showed that 'dust inflow' of the physical site environment evaluation, 'size of living room' of the residence size evaluation, 'heating' of the residence indoor environment evaluation, and 'burden of maintenance expense' in the behavioral factor evaluation significantly influences the overall satisfactory level.

• Journal of the Korean Wood Science and Technology
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• 제37권5호
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• pp.440-450
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• 2009

In case of wood flooring, the high emissivity would be one of the most important properties especially as the cover material of underfloor heating system. The FIR (Far Infrared) materials such as wood emit FIR energy by heating, which has been used as the medical therapy such as dry sauna. This research investigated the emissivity and the emission power of wood composites by comparing the amount of the three heat transfer modes transferred by infrared radiation which came from the increased temperature of the bottom board of the plywood box by the heater. The results showed the value of radiation mode was the highest mode for the plywood box, and the convection mode was the main mode for the aluminum box. The rate of convection was 81.8% in the aluminum box and 48.2% in the plywood box, respectively. In case of the rate of radiation, the aluminum box showed only 15.4% and the plywood box showed 51%. The emissivity and the emission power of birch plywood showed the same values as those of wood. The amount of energy required for the temperature rising of water within vial in the aluminum box and in the plywood box were 3.32 kJ and 6.70 kJ respectively, which showed that the vial temperature of the plywood box was two times higher than that of the aluminum box.

• KIEAE Journal
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• 제12권6호
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• pp.85-92
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• 2012

The Korean government has introduced building regulations with improved energy conservation measures, including higher insulation levels for building envelope. However, there are many existing buildings that tend to consume more energy for heating and cooling than new buildings, as they were built under the former regulations with relatively higher U-values of walls and glazing. In order to improve energy efficiency in existing buildings, green remodelling of building envelope and building services are required. For existing buildings, building services improvements have been achieved through energy service company(ESCO), but much attention has not been paid to building envelope improvements with various reasons, such as uncertainty of energy saving effect design issues and costs. The aim of this study is to evaluate the impact of building envelope improvements in a typical commercial building on its heating and cooling energy loads. The results show that the improvement of glazing with lower U-values has the highest energy saving effects, followed by wall, roof and floor, under the condition of same level of insulation improvements. However, high insulated glazing increased LCC because of higher initial investment costs.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 G
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• pp.3319-3321
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• 1999

Pt-RTD and Micro Heater was fabricated by using MgO as medium layer in order to improve adhesion of Pt thin-films to $SiO_2$ layer, MgO layer improved adhesion of Pt thin-films to $SiO_2$ layer without any chemical reactions to Pt thin-films under high annealing temperatures, In the analysis of properties of Pt-RTD, TCR value had 3927 $ppm/^{\circ}C$ and liner in the temperature range of $25-400^{\circ}C$. The temperature of Pt micro-heater had up to $400^{\circ}C$ with 1.5watts of the heating power. In investigating output characteristics of flow sensors output voltages increased as gas flow rate and its conductivity increased due to increase of heat-loss from sensor to external. Output voltage was 82 mV at $N_2$ flow rate of 2000sccm, heating power of 1.2W.