• Journal of the Korean earth science society
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• v.43 no.2
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• pp.312-323
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• 2022

This study began with the hypothesis of whether "solar radiation" and "terrestrial radiation" can be replaced by "visible radiation" and "infrared radiation", respectively. To this end, we investigated the perceptions of high school students who completed the Earth Science I course through a questionnaire to reveal how they perceived each concept. We also analyzed the descriptions and illustrations of textbooks that may have affected their perceptions. All of the students who participated in the questionnaire recognized solar radiation as radiation emitted only in the visible light region. About 35% of the students recognized convection, conduction, and latent heat as energy transfer by radiation in the Earth's heat budget. By analyzing six types of Earth Science I textbooks in the 2015 revised curriculum, we observed that two types introduced the terms "shortwave radiation" and "longwave radiation" but had no explanation for them, while the other two described solar radiation as "radiation mainly in the visible light region" or "radiation in short wavelengths". Regarding solar and terrestrial radiation in the last two types, there was no explanation for the wavelength regions, or ambiguous terms such as "short wavelength" and "long wavelength" were used. In addition, the two textbooks contained some errors in the illustration of the energy budget. Considering that textbooks described solar and terrestrial radiation without defining the exact terms for shortwave and longwave radiation, learners are likely to recognize solar and terrestrial radiation as visible and infrared radiation, respectively. This finding implies that vague statements or errors in textbooks can cause or reproduce students' misconceptions. The discussion in this study is expected to be used as a helpful reference material for teaching and learning processes regarding the Earth's radiation equilibrium and heat budget, and thereby contribute to proposing reasonable description plans for future textbook writing.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.295-305
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• 1993

Thermal performance of test cell of model hot water Ondol house was simulated by equivalence heat resistence and heat capacity method. In this method wall was replaced by two equivalence and one heat capacity. This method enables to simulate the variation of temperature of each element of model house. The effect of pipe diameter, pitch of pipe and with or without consideration of inter-radiation between wall surfaces on the energy consumption rate were investgated. Results show that radiations between the ground surface of room and wall surfaces contribute to the heating of room air by reducing the convection heat loss through the wall surfaces.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.44-44
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• 2023

지표면 위 에너지 수지, 즉 순 복사에너지가 어떤 비율로 지열, 현열, 잠열로 분할되는지를 이해하는 것은 매우 중요한 문제이지만, 에너지 분할과 주변 환경 변수 사이의 인과관계를 역학적으로 설명하는 것은 난제로 남아있다. 이 연구에서는 지표면 에너지 분할에서 어떠한 조건에서라도 보편적으로 발견되는 특성을 찾아서 다양한 식생 조건에서 관측된 복사에너지 및 열 플럭스 관측소의 자료를 토대로 각 에너지 항의 시간 변동성을 분석했다. 시계열 분석을 위해 공분산 기법을 통해 관측한 현열 및 잠열 자료를 제공하는 Fluxnet 자료를 사용했으며, International Geosphere-Biosphere Programme (IGBP) 구분법에 따라 낙엽수림, 상록수림, 농지 및 사바나에 위치한 관측소의 자료를 비교 분석했다. 모든 관측소에서 에너지 수지에서 현열과 잠열의 합이 전체 순 복사에너지에서 차지하는 비중은 시간에 따라 큰 변화를 보이지 않는다는 특성을 발견했다. 하지만, 현열 또는 잠열이 차지하는 비중은 큰 계절성을 보여주고 있었다. 이를 종합하면 현열과 잠열이 상호보완적으로 발생한다는 것을 의미한다. 한편 시간에 따른 두 열 플럭스의 움직임은 해당 관측소 근처에서 서식하는 식생 특성과 깊게 관련됐음을 확인했다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.1
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• pp.341-348
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• 1991

An efficient tool to deal with a multi-dimensional radiative heat transfer is in strong demand to analyze various thermal problems combined either with other modes of heat transfer or with combustion phenomena. The current study examined the discrete ordinates method (DOM) for a coupled radiative and conductive heat transfer in rectangular enclosures in which either nonscattering or scattering medium is present. The results were compared with the other benchmarked approximate solution. The efficiency and accuracy of the DOM were thus validated.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1294-1299
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• 2004

Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step, $2^{nd}$ order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results for diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam, however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam, shock capturing schemes such as TVD scheme are need to be developed.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.3_4
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• pp.414-421
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• 2004

To reduce farmer's stress from solar radiation and ultraviolet radiation(UV), the sunshade hat with a large brim and special structure for ventilation was developed and tested with manikin heads outdoors at previous study(Kim and Choi, 2002). To evaluate the protection efficiency of the sunshade hat, human trial test was performed at outdoors. The results were as follows; Skin temperatures(7 sites), heart rate, temperature inside the hats, temperature and relative humidity inside clothing on the back in wearing developed sunshade hat were significantly lower than those in wearing the controlled hat. In subjective sensation, subjects answered to feel significantly hotter, more humid and more uncomfortable in wearing the controlled hat. But relative humidity inside the hats was significantly higher in wearing developed hat. In rectal temperature, there were no significant differences between two hats.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.04a
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• pp.160-164
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• 2011

국내 건축법에서는 화재의 확산을 방지하기 위해 방화구획을 설치하여 인명피해와 재산피해를 최소화 하고 있다. 따라서 방화구획 개구부의 방화문, 방화셔터 등 각종 배관 관통부 시스템의 화재저항 성능이 중요하다. 이에 본 연구에서는 방화구획 중 넓은 면적에 사용되는 방화셔터를 각 종류별 내화성능실험을 통하여 방화셔터의 방화성능 확인과 더불어 실험시 방화셔터에서 발생하는 복사열의 측정을 통하여 화재가 확대될 수 있는 위험성을 예측하였다.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1570-1575
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• 2004

In order to evaluate the performance of fire-fighting agents used to protect structures from heat and fire damages, the thermal characteristics of fire-protection foams are experimentally investigated. The current research focuses on the destruction of a fire-fighting foam subjected to heat radiation. A simple repeatable test for fire-protection foams subjected to fire radiation is developed. This test involves foam generation equipment, a fire source for heat generation, repeatable test procedures, and data acquisition techniques. Results of the experimental procedure indicated that each thermocouple within the foam responded in a similar manner and gradually to a temperature of $15^{\circ}C{\sim}20^{\circ}C$. At this point, each trace generally rises to a temperature of approximately $90^{\circ}C$. The temperature gradient in the foam as time passes increases with increased foam expansion ratio. In addition, it is determined that the temperature gradient along the foam for depth decreases with increased foam expansion ratio.

• Journal of the Korean Home Economics Association
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• v.40 no.10
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• pp.77-85
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• 2002

This study was conducted to evaluate the efficiency of various fabrics in protecting from solar radiation and ultraviolet radiation(UV). Six kinds of fabrics were selected and examined in singles or doubles. It was studied how the materials and the thickness of air layer between the fabric and the floor affected the protection efficiency of fabrics from sunlight. The results were as followes; 1) Protection from solar radiation: In the case of over 2 cm air layer, doubled fabric composed of aluminum coating-nylon and white or black polyester/cotton(T/C) was the most protective(p<0.001). In the case of 0 cm air layer, the case without fabric and white T/C were more effective(p<0.001). And the thicker the air layer the more effective the protection. 2) Protection from UV : Doubled fabric composed of aluminum coating-nylon and black T/C was the most protective(p<0.001) and the thinner the air layer the more effective the protection(p<0.001).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.201-207
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• 2006

Transient radiative heat transfer is analyzed in a one-dimensional slab using finite volume method (FVM). In this study, the step, $2^{nd}$ order upwind, and QUICK schemes are used for incident diffuse radiation and collimated beam, respectively. The results fer diffuse radiation show that all schemes applied in this study give good agreements with available published results. In case of collimated beam however, the results show deviations from the analytical solutions. To successfully describe the propagations of collimated beam shock capturing schemes such as TVD scheme are need to be developed.