• 한국안전학회지
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• 제7권4호
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• pp.13-21
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• 1992

The purpose of this reserch is to suggest grinding temperature for high effect grinding and to clarify the sufficient grinding heat by experiment and theory(developed finite element program). Main results to be obtained are as follows : 1) The grinding temperature distribution by F. E. M is comparatively in good apreement with the experimental results. 2) The up cut grinding method of grinding methods is decreased burning effect. 3) Regardless of the table speed on the temperature distribution in grinding surface layer, cooling effect is about 6-8times when developed nozzle is used.

• Smart Structures and Systems
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• 제17권6호
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• pp.881-901
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• 2016

In this study, a method to compensate the effect of temperature variation on impedance responses which are used for prestress-loss monitoring in prestressed concrete (PSC) girders is presented. Firstly, an impedance-based technique using a mountable lead-zirconate-titanate (PZT) interface is presented for prestress-loss monitoring in the local tendon-anchorage member. Secondly, a cross-correlation-based algorithm to compensate the effect of temperature variation in the impedance signatures is outlined. Thirdly, lab-scale experiments are performed on a PSC girder instrumented with a mountable PZT interface at the tendon-anchorage. A series of temperature variation and prestress-loss events are simulated for the lab-scale PSC girder. Finally, the feasibility of the proposed method is experimentally verified for prestress-loss monitoring in the PSC girder under temperature-varying conditions and prestress-loss events.

• 한국도로학회논문집
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• 제17권4호
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• pp.33-40
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• 2015

PURPOSES: Evaluation of the wind speed effect on the temperature drop of an asphalt mixture during construction, by using the transient heat transfer theory and dominant convective heat transfer coefficient model. METHODS: Finite difference method (FDM) is used to solve the transient heat transfer difference equation numerically for various wind speeds and initial temperature conditions. The Blasius convective heat transfer coefficient model is adapted to account for the effect of wind speed in the temperature predictions of the asphalt mixture, and the Beaufort number is used to select a reasonable wind speed for the analysis. As a function of time and depth, the temperature of the pavement structure is predicted and analyzed for the given initial conditions. RESULTS : The effect of wind speed on the temperature drop of asphalt mixture is found to be significant. It seems that wind speed is another parameter to be accounted for in the construction specifications for obtaining a better quality of the asphalt mixture. CONCLUSIONS: It is concluded that wind speed has a significant effect on the temperature drop of the asphalt layer. Although additional field observations have to be made to reflect the effect of wind speed on the construction specifications, it appears that wind speed is a dominant variable to be considered, in addition to the atmospheric temperature.

• 한국산업융합학회 논문집
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• 제14권4호
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• pp.143-149
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• 2011

The experiment has been investigated the room temperature change under adjusting 4-way valve which was installed for cooling and heating switch. Beside, the temperature of heat pump was controlled automatically for autonomously adjusting temperature and maintaining a constant room temperature. As results, Inlet & outlet temperature differences of compressor are $95^{\circ}C$ in cooling condition and $57^{\circ}C$ in heating condition. Therefore, Compression efficiency of cooling effect is higher than heating effect. In addition, Heat exchange effect of Cooling system condition is higher than heating system. This results can be used for studying about automatic temperature control of cooling and heating system with heat pump and 4way valve.

• 자원ㆍ환경경제연구
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• 제25권2호
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• pp.141-178
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• 2016

본 논문은 실시간으로 측정되는 자동원격검침(AMR) 전력수요량을 사용하여 산업별 전력수요의 기온효과에 대한 특성과 패턴을 분석하였다. AMR 전력사용량의 시계열적 특징으로부터 장기 추세효과와 중기 기온효과 그리고 단기 특수일 효과로 구성되는 공적분 모형을 구축하고, 기온효과를 연속적인 기온반응함수를 통하여 분석하기 위하여 기온반응함수를 푸리에 플렉서블 폼(Fourier Flexible Form; FFF) 비선형 함수로 추정하였다. 추정 결과 도출된 기온반응함수와 기온효과를 통하여 기온효과가 뚜렷하게 나타나는 서비스업군과 기온효과가 미약하게 나타나는 제조업군으로 구분하였다. 그리고 기온효과가 뚜렷하게 나타나는 서비스업군을 기온반응함수의 추정치에 근거하여 여름피크 산업과 겨울피크 산업으로 구분하였다. 이러한 실증분석 결과는 산업별, 계절별 전력수요관리정책 수립에 정책적 기초를 제공한다. 또한 실시간으로 측정되는 AMR 전력수요량 분석이라는 점에서 시차의 발생없이 신속하게 전력수요관리에 반영될 수 있다는 의미가 있다.

• Structural Engineering and Mechanics
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• 제65권4호
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• pp.389-400
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• 2018

An exact solution for the title problem was obtained in closed-form fashion considering general boundary conditions. The expressions of moment, shear and shear coefficient (or shear factor) of cross section under the effect of arbitrary temperature distribution were first derived. In view of these relationships, the differential equations of Timoshenko beam under the effect of temperature were obtained and solved. Second, the characteristic equations of Timoshenko beam carrying several spring-mass systems under the effect of temperature were derived based on the continuity and force equilibrium conditions at attaching points. Then, the correctness of proposed method was demonstrated by a Timoshenko laboratory beam and several finite element models. Finally, the influence law of different temperature distribution modes and parameters of spring-mass system on the modal characteristics of Timoshenko beam had been studied, respectively.

• Applied Microscopy
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• 제47권3호
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• pp.121-125
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• 2017

This study deals the prediction of temperature effect on low-frequency dispersion of alternating current (AC) conductivity spectra of composite materials based on copolymer reinforced with carbon black (CB) particles. A sample of ethylene butylacrylate loaded with 13% of CB particles were prepared and investigated using the impedance spectroscopy representation in the frequency range from 40 Hz to 0.1 MHz and temperature range from $20^{\circ}C$ to $125^{\circ}C$. The dielectric constant, ${\varepsilon}^{\prime}$, and dielectric losses, ${\varepsilon}^{{\prime}{\prime}}$, were found to decrease with increasing frequency. The frequency dependence of the AC conductivity follows the universal power law with a large deviation in the high frequency region, the positive temperature coefficient in resistivity effect has been observed below the melting temperature which makes this composite potentially remarkable for industrial applications.

• 한국조경학회지
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• 제27권1호
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• pp.19-28
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• 1999

This survey is to investigate the effect of plants and waterscape facilities on the thermal indoor environment and to provide basic data for proper plant cultivation to enhance indoor landscape. The survey of the measure of comfort on the indoor environment for the residents of Taegu shows that the measure of comfort on the thermal-environment, which consist of temperature and humidity, has more negative responses than the measure on lighting . are . sound environment, which consists of air freshness, lighting condition and sound environment. The experiments on the effect of the amount of leaves and the distance of plants on the indoor thermal-environment are made. The experimental results illustrate that, as the capacity of a plant becomes greater and the distance from the plant shorter, the falling effect of temperature and the rising effect of humidity on the top of the plant are taken higher than on the side of the plant. When the same amount of leaves is set up, the distance range of the rising effect of humidity becomes wider than that of the falling effect of temperature. The investigation of the effect of waterscape facilities on the indoor thermal-environment shows that temperature and humidity of the space with installed waterscape facilities are lower and higher than without facilities, respectively.

• Structural Engineering and Mechanics
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• 제68권4호
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• pp.459-473
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• 2018

Temperature fields and temperature deformations induced by time-varying solar radiation, shadow, and heat exchange are of great importance for the ride safety and quality of the maglev system. Accurate evaluations of their effects on the dynamic performances are necessary to avoid unexpected loss of service performance. This paper presents a numerical approach to determine temperature effects on the maglev train/guideway interaction system. Heat flux density and heat transfer coefficient of different components of a 25 m simply supported concrete guideway on Shanghai High-speed Maglev Commercial Operation Line is calculated, and an appropriate section mesh is used to consider the time-varying shadow on guideway surfaces. Based on the heat-stress coupled technology, temperature distributions and deformation fields of the guideway are then computed via Finite Element method. Combining guideway irregularities and thermal deformations as the external excitations, a numerical maglev train/guideway interaction model is proposed to analyze the temperature effect. The responses comparison including and excluding temperature effect indicates that the temperature deformation plays an important role in amplifying the response of a running maglev, and the parameter analysis results suggest that climatic and environmental factors significantly affect the temperature effects on the coupled maglev system.

• 한국농공학회논문집
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• 제55권4호
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• pp.65-72
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• 2013

The physical, mechanical, water purification and temperature properties of fiber reinforced porous hwang-toh green roof concrete have been evaluated in this study. The effect of the depending on replacement ratio of blast furnace slag to cement was investigated such that the replacement ratio is varied to 0 % and 30 %. Also, the replacement ratios of hwang-toh were 0, 20 and 30 %. The polyvinyl alcohol fiber was used for the reinforcing fiber. A series of pH test, unit weight, void ratio, compressive strength, after purification and variation of temperature test have been performed to evaluate the performance, water purification effect and temperature properties of the fiber reinforced porous hwang-toh green roof concrete. The test results indicate that the physical and mechanical properties of fiber reinforced porous hwang-toh green roof concrete is affected by the replacement ratio of the blast furnace slag and hwang-toh contents. Results of purifying water showed that the water purification effect of porous hwang-toh green roof concrete is about 40 %. Also, the temperature properties test results indicate the green roof blocks using fiber reinforced porous hwang-toh green roof concrete have insulation and temperature reduction effect.