• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2001.05a
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• pp.45-52
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• 2001

The study on the heat exchanger with catalytic combustion was performed as the development of the catalytic combustion applications. This study tried to achieve the both goals-the mixture preheating and the heat transfer to working fluid simultaneously by using the steady state catalytic combustion. The combustion characteristics were investigated with the quantitative, qualitative experimental variants of the mixture. In addition, the temperature distribution of catalytic layer was investigated to investigate the correlation between the combustion characteristics and the heat balance of the catalytic layer. As a result, the steady state reaction within the appropriate range of temperature is the critical factor in catalytic applications. To get this, the sensible control of both the mixture flow and the heat balance of catalytic layer were required.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.505-513
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• 2016

The qualitative distribution of a fractured aquifer was characterized by electrical resistivity surveying as a part of basic groundwater investigation in Jangseong. The results were then used to choose sites for observation wells. The locations and distributions of permeable discontinuities were studied by analyses of temperature logs, a borehole image-processing system (BIPS), and hydraulic pressure testing using a double packer. The pressure test showed that the size of the discontinuities correlated with the Lugeon value and the results of the temperature log. The results show that temperature measurement is an effective method to identify permeable discontinuities, with the temperature difference correlating with the size of the aperture of the discontinuity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.425-430
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• 2019

Zinc coatings are widely used because of their environmental friendliness and high performance. In general, the coating temperature is a major factor in determining the coating layer thickness and coating quality. In the case of a zinc coating, a uniform and appropriate coating temperature is required. In this study, a thermal flow simulation of the air flow was performed to analyze the temperature distribution of a zinc spray coating room in a natural convection state. Using SolidWorks, modeling was performed for two spray coating rooms, a preheating room, and a drying room, and a thermal flow coupled analysis was performed using ANSYS-FLUENT. As a result of the analysis, the temperature distribution characteristics in the spray coating rooms were determined. It was found that the present temperature was below the target temperature of $25^{\circ}C$. Simulations were conducted for two different boundary conditions (one with a heater added and another with the open part closed). The simulation results show that the method of closing the open part is better than adding the heater.

• Korean Journal of Food Science and Technology
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• v.8 no.1
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• pp.42-46
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• 1976

In order to compare the quality of starches, isolated from the various barley and naked barley species, the gelatinization-temperature and alkali number were determined for 11 species of barley and 13 species of naked barley. The results are as follows; 1. Gelatinizations start at $51-59^{\circ}C$ and complete at $58-64^{\circ}C$ in range. Average gelatinization temperature of the starches from naked barley showed $3^{\circ}C$ lower than those from barley while small differences were observed between species for both barleys. 2. Alkali number varies between 8.0 to 9.5. No significant changes of alkali number were observed between both barleys (8.8 for naked barley and 8.7 for barley in average).

• Journal of Korean Association for Spatial Structures
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• v.7 no.6
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• pp.91-101
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• 2007

The purpose of this study is to provide fundamental cooling design data for the large public enclosures as gymnasium. This study executed indoor thermal environment verification of the existing gymnasium by measuring temperature distribution with and without cooling the space in summer. Colling loads from human body was not considered. We examined various indoor thermal environment factors of the large enclosed space in this study which include vertical and horizontal temperature distribution, supply and return air flow feature, thermal comfort environment feature, amount of ventilation and etc.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2003.07a
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• pp.213-219
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• 2003

본 연구에서는 새로운 개념의 건조방법을 연구하여 곡물건조의 변화를 도모하고자 원적외선ㆍ열풍 복합열을 이용한 곡물건조기를 개발하게 되었다. 그 결과를 요약하면 다음과 같다. 가. 방사체길이가 1,680mm일 때 보다 1,470mm일 때가 방사체 표면온도가 높게 나타났고, 안정적인 것으로 나타났다. 열풍온도를 5$0^{\circ}C$로 설정했을 때 방사체의 표면온도분포는 280-29$0^{\circ}C$을 유지하였고, 6$0^{\circ}C$일 때는 30$0^{\circ}C$ 부근에서 유지되는 것을 확인할 수 있었다. 두 조건 모두에서 온도편차는 크게 나타나지 않았으므로 균일 건조가 이루어지는 것을 의미하며, 곡물의 품질저하에 영향을 미치지 않는 것으로 판단된다. 나. 열풍온도 5$0^{\circ}C$, 조사거리 125mm, 방사체 길이 1,470mm에서 방사체 길이방향으로 위치에 따라서 온도편차를 측정했을 때 버너를 기점으로 해서 근거리에서부터 원거리까지 균등 분할하여 5점의 온도를 측정하여 그 변화곡선을 분석한 결과 위치 3에서 온도가 높았고, 계속해서 위치 4, 5, 2, 1순으로 나타났다. 버너의 근거리에서보다 원거리에서 온도가 높게 나타난 것은 원적외선방사체를 통과하는 열풍이 빠져나가도록 되어있는 열풍유동관이 버너 원거리에 위치하고 있어 버너에 불꽃이 점화되면서 열풍이 방사체 끝쪽으로 유동되기 때문이다. 다. 건조실 수직면 길이방향의 온도는 열풍공기가 열풍실에서 유입되는 하단부이 온도가 높게 나타났고, 버너쪽과 송풍기쪽의 온도차는 나타나지 않아 온도분포의 좌우 대칭이 잘 되어 균일 건조가 되는 것으로 판단된다 이러한 현상은 건조실의 수평면에 대해서도 같은 현상이 나타났다. 라. 바닥면에서 상부로 올라갈수록 낮은 온도분포를 나타내고 있는 것은 상부에는 외부공기가 유입되면서 온도가 떨어지는 반면 하부에는 외부공기 유입이 적기 때문으로 사료된다. 또한 열풍실의 길이방향 위치별 온도 분포에서도 같은 현상으로 나타났고, 버너쪽과 송풍기쪽의 온도편차는 나타나지 않아 균일 건조를 기대할 수 있다. 마. 열풍온도를 45$^{\circ}C$로 설정하고 조사거리와 방사체 길이를 각각 119, 1,470mm로 하여 벼의 건조성능시험을 열풍건조기(대비구)와 비교시험 결과 시험구에서 건감률, 건조소요에너지가 각각 0.58%(w.b.), 470kcal/kg - water로 대비구보다 각각 건감율은 23% 높았고, 건조소요에너지는 2%의 절감되었다. 바. 건조기에서 발생되는 소음은 버너쪽 근처에서는 대비구 94.12㏈의 87%에 불과하였으나, 거리가 멀어질수록 차이는 크지 않았다. 이것은 버너에서 멀어질수록 외부적인 요인이 소음에 영향을 미쳤기 때문인 것으로 생각된다. 사. 시작기와 대비구간의 경제성에서 시작기의 구입가격이 20% 비싸기 때문에 시간당 고정비가 높았으나, 건조성능이 우수하여 건조비용이 69,350원/톤으로 대비구보다 14% 절감되는 것으로 나타났다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.5
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• pp.477-485
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• 2012

Fluid flow and heat transfer in horizontal ducts are strongly coupled with large changes in thermodynamic and transport properties near the critical region as well as the gravity force. Numerical analysis has been carried out to investigate convective heat transfer in horizontal rectangular ducts for water near the thermodynamic critical point. Convective heat transfer characteristics, including velocity, temperature, and the properties as well as local heat transfer coefficients along the ducts are compared with the effect of proximity on the critical point. When there is flow acceleration because of a density decrease, convective heat transfer characteristics in the ducts show transition behavior between liquid-like and gas-like phases. There is a large variation in the local heat transfer coefficient distributions at the top, side, and bottom surfaces, and close to the pseudocritical temperature, a peak in the heat transfer coefficient distribution resulting from improved turbulent transport is observed. The Nusselt number distribution depends on pressure and duct aspect ratio, while the Nusselt number peak rapidly increases as the pressure approaches the critical pressure. The predicted Nusselt number is also compared with other heat transfer correlations.

• Journal of the Korea Concrete Institute
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• v.19 no.2
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• pp.189-197
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• 2007

Concrete tunnel lining must be designed to having the fireproof performance because the lining are sometimes exposed to very high temperature due to traffic accident. Such fire temperature may cause explosion of concrete, or collapse of tunnel structure. The purpose of this study is to obtain the fundamental fireproof behavior of fire resistance-engineered cementitious composites(FR-ECC) under fire temperature in order to use the fire protection material in tunnel lining system. The present study conducted the experiment to simulate fire temperature by employing 2 types of FR-ECC and investigated experimentally the explosion and cracks in heated surface of these FR-ECC. Employed temperature curve were hydro carbon(HC, ECl) criterion, which are severe in various criterion of fire temperature. The numerical analysis is carried out the nonlinear transient heat flow analysis and verified against the experimental data. The complex features of behavior in fire conditions, such as thermal expansion, plasticity, cracking or crushing, and material properties changing with temperature are considered. By the use of analytical model, the concrete tunnel subjected to fire loads were analyzed and discussed. With comparison of current concrete materials and FR-ECC, the experimental and analytical results of FR-ECC shows the better fire resistance performance than the other.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.194-201
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• 2005

도시에서의 빛의 연출은 도시의 축을 부각시키고, 가로의 아이덴티티를 연출함으로서 도시의 인지도를 향상시킬 수 있다. 또한 야간의 경관은 인공조명을 이용한 빛의 연출로 주간과는 다른 빛환경 경관을 연출할 수 있다. 이에 본 연구는 도시 가로 중에서 상업가로와 주거가로를 대상으로 주 야간의 빛환경 특성을 분석하여, 가로의 용도에 따른 주야간의 빛환경 차이를 고찰하였다. 이를 위하여 두 가로의 일정길이에 대하여 수평면조도, 스칼라 조도, 휘도 및 색온도를 측정하였으며 측정결과를 용도별, 주 야별로 비교하여 분석하였다. 측정한 결과를 정리하면 다음과 같다. (1)수평면조도의 측정 결과, 주간의 주거가로에 비하여 상업가로가 28.8[%] 높게 나타났으며 야간의 경우 87.2[%] 높게 나타났다. (2) 스칼라조도의 측정결과, 스칼라조도의 특성상 전반적으로 균일한 분포를 보이며, 수평면 조도와 마찬가지로 주간에 비하여 야간에 84[%] 높은 값이 측정되었다. (3) 휘도의 측정 결과, 주간 배경에 대한 대상의 휘도비는 상업과 주거가로가 1:2이하로 나타나 조화로운 가로경관을 연출하며, 야간배경에 대한 대상의 휘도비는 상업가로는 1:17로 활기 있는 경관을 연출하고 주거가로는 1:5로 가로경관 이미지에 적당한 강조효과가 나타났다. (4) 색온도의 측정 결과, 주간의 배경은 맑은 하늘의 색온도를 나타냈으며 대상은 상쾌하고 활동적인 이미지의 색온도를 나타내었다. 또한 야간의 경우 상업가로와 주거가로 모두 나트륨 등의 영향을 받아 전반적으로 따뜻한 느낌의 색온도가 연출되었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.363-366
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• 2005

A micro flow sensor on silicon substrate allows the fabrication of small components where many different functions can be integrated so that the functionality of the sensors can be increased. Further more, due to the small size of the elements the sensors can be quite fast. A thermal mass flow sensor measures the asymmetry of temperature profile around the heater which is modulated by the fluid flow. In normal, a mass flow sensor is composed of a central heater and a pair of temperature sensing elements around the heater. A new 2-D wide range micro flow sensor structure with three pairs of temperature sensors and a central heater was proposed and numerically simulated by the Finite difference formulation to confirm the feasibility of the flow sensor structure.