• Smart Structures and Systems
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• 제19권2호
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• pp.137-149
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• 2017

Under the interference of the temperature effect, the alternation of cable force due to damages of a cable-stayed bridge could be difficult to distinguish. Considering the convenience and applicability in engineering practice, simple air or cable temperature measurements are adopted in the current study for the exclusion of temperature effect from the variation of cable force. Using the data collected from Ai-Lan Bridge located in central Taiwan, this work applies the ensemble empirical mode decomposition to process the time histories of cable force, air temperature, and cable temperature. It is evidently observed that the cable force and both types of temperature can all be categorized as the daily variation, long-term variation, and high-frequency noise in the order of decreasing weight. Moreover, the correlation analysis conducted for the decomposed variations of all these three quantities undoubtedly indicates that the daily and long-term variations with different time shifts have to be distinguished for accurately evaluating the temperature effect on the variation of cable force. Finally, consistent results in reducing the range of cable force variation after the elimination of temperature effect confirm the validity and stability of the developed method.

• 소성∙가공
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• 제18권2호
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• pp.107-111
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• 2009

Temperature variation happens in micro prism roll mold processing system during machining the prism pattern roll mold using manufacturing optical films of LCD (liquid crystal display). This temperature variation induces pitch errors of the prism patterns. The temperature variation displaces the positions of the diamond cutting tool on the roll which was coated by the copper. In order to prevent the pitch errors, the stabilizing the temperature of machining environment is needed. Therefore, the researching on the temperature variation of the ultra-precision roll mold processing system on the machining of micro prism rot 1 mold is needed. In this paper, the temperature variation of micro prism roll mold processing system is researched, the influence is analyzed, and the study for reducing the pitch errors carried out.

• Tribology and Lubricants
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• 제17권3호
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• pp.228-235
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• 2001

EHL analysis of connecting rod bearing is proposed which includes effects of temperature variation in lubrication film. Lubrication film temperature is treated as a time-dependent, two-dimensional variable which is averaged over the film thickness, while connecting rod big end temperature is assumed to be time-independent and three-dimensional. It is assumed that a portion of the heat generated by viscous dissipation in the lubrication film is absorbed by the film itself, and the remainder flows into the bearing surface. Mass-conserving cavitation algorithm is applied and the effect of variable viscosity is included to solve the Reynolds equation. Simulation results of the connecting rod bearing in internal combustion engine are presented. It is shown that the temperature variation has remarkable effects on the bearing performance. It is concluded that the EHL analysis considering effects of the temperature variation is strongly recommended to predict the connecting rod bearing performance in internal combustion engine.

• 태양에너지
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• 제12권2호
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• pp.1-8
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• 1992

본 연구는 동계 외기온 데이타의 시각별 변동특성을 파악하기 위하여 연변동 성분 및 기간변동 성분을 제거한 일변동 성분의 매 시각별 외기온 데이타에 대해서 일교차의 발생요인에 대해서 분석하였다. 또한 동계시각별 외기온의 주파수 특성에 대해서 검토하였으며 외기온 데이타의 수식화의 가능성을 제시하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.114-120
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• 2000

EHL analysis of connecting rod bearing is proposed which includes effects of temperature variation in lubrication film. Lubrication film temperature is treated as a time-dependent, two-dimensional variable which is averaged over the film thickness, while connecting rod big end temperature is assumed to be time-independent and three-dimensional. It is assumed that a portion of the heat generated by viscous dissipation in the lubrication Him is absorbed by the film itself, and the remainder flows into the bearing surface. Mass-conserving cavitation algorithm is applied and the effect of variable viscosity is included to solve the Reynolds equation. Simulation results of the connecting rod bearing of internal combustion engine are presented. It is shown that the temperature variation has remarkable effects on the bearing performance. It is concluded that the EHL analysis considering effects of the temperature variation is strongly recommended to predict the bearing performance of connecting rod big end On internal combustion engine.

• Smart Structures and Systems
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• 제15권4호
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• pp.1159-1175
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• 2015

In this study, the effect of temperature variation on the wireless impedance monitoring is analyzed for the tendon-anchorage connection of the prestressed concrete girder. Firstly, three impedance features, which are peak frequency, root mean square deviation (RMSD) index, and correlation coefficient (CC) index, are selected to estimate the effects of temperature variation and prestress-loss on impedance signatures. Secondly, wireless impedance tests are performed on the tendon-anchorage connection for which a series of temperature variation and prestress-loss events are simulated. Thirdly, the effect of temperature variation on impedance signatures measured from the tendon-anchorage connection is estimated by the three impedance features. Finally, the effect of prestress-loss on impedance signatures is also estimated by the three impedance features. The relative effects of temperature variation and prestress-loss are comparatively examined.

• 한국태양에너지학회 논문집
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• 제27권4호
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• pp.67-75
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• 2007

This study intends to the adequacy inspection of the room temperature variation rate that is available in the building heat performance evaluation index, so we performed the sensitivity analysis about the room temperature variation rate and the energy consumption in the room. For these purpose, we supposed the models which are composed of the various window area, insulation thickness and ventilation rate. Then we analyzed the simulation using the ESP-r and Seoul weather data. In this research, the pattern of the increasing & decreasing rate of annual load according to the change of the various design factors is similar to the pattern of increasing & decreasing rate of not the K-values but the room temperature variation rate. Also we derive the optimum value of the various design factors and the room temperature variation rate in this analysis model. Further study is to be required the development of convenient tool to use in the real design.

• 한국산학기술학회논문지
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• 제10권11호
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• pp.3110-3114
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• 2009

회전자 온도 변화는 유도 전동기 제어기 설계에 있어서 중요한 쟁점이다. 문헌에서, 수많은 연구들이 회전자 온도 변화를 고려하지 않는다면, 그에 기인한 심각한 성능 저하를 언급해왔다. 하지만, 이러한 연구들은 추종 성능 관점에서 주로 Field-oriented 제어기에 초점을 두고 있으며, 단위 전류당 최대 토크 제어기와 같이 최적 제어의 경우에서의 성능에 미치는 회전자 온도 변화의 영향에 대한 연구는 전무하다. 본 연구는 회전자 온도가 시간에 따라 변화함에 따라, 단위 전류당 최대 토크 제어기의 성능에 어떻게 영향을 미치는지를 조사한다. 이를 위해, 두 가지 방법으로 단위 전류당 최대 토크 제어기의 목적이 성취되는 지를 점검한다. 즉, 요구되는 토크를 발생시키면서 동시에 최소 가능한 고정자 전류를 필요로 하는 것이다. 실험실 실험결과는 추종 성능과 단위 전류당 최대 토크 조건이 회전자 온도가 변화함에 따라 심각한 영향을 받으며, 결과적으로 단위 전류당 최대 토크 제어기의 성능저하를 초래함을 보여준다.

• 한국패류학회지
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• 제25권2호
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• pp.93-96
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• 2009

Unexpected mass mortality has been one of the drawbacks in front of the stable production of Japanese scallop (Patinopecten yessoensis) on the Gangwon coasts of the East Sea. The preliminary data from our routine observation revealed that the mortality appeared to be related to variation of water temperature in the farming site and the degree of the mortality was dependent on scallop strain. The present study performed to verify the preliminary findings exhibited that the mortality was closely related to daily temperature variation rather than monthly variation. Daily temperature variation was particularly damageable to the scallop during the temperature elevation period. Scallops from hatchery seeds (Chinese strain) were more tolerant against the temperature variation over those from wild seeds. The hatchery scallop gain of the temperature tolerance was probably due to their larval experience to higher temperature in the hatchery as well as their maternal genetic acclimation to upper temperature extreme of the Chinese environment which was recently found.

• Smart Structures and Systems
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• 제25권2호
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• pp.135-153
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• 2020

There has been a sustained interest towards the non-contact structural displacement measurement by means of videogrammetric technique. On the way forward, one of the major concerns is the spurious image drift induced by temperature variation. This study therefore carries out an investigation into the temperature effect of videogrammetric technique, focusing on the exploration of the mechanism behind the temperature effect and the elimination of the temperature-caused measurement error. 2D videogrammetric measurement tests under monotonic or cyclic temperature variation are first performed. Features of measurement error and the casual relationship between temperature variation and measurement error are then studied. The variation of the temperature of digital camera is identified as the main cause of measurement error. An excellent linear relationship between them is revealed. After that, camera parameters are extracted from the mapping between world coordinates and pixels coordinates of the calibration targets. The coordinates of principle point and focal lengths show variations well correlated with temperature variation. The measurement error is thought to be an outcome mainly attributed to the variation of the coordinates of principle point. An approach for eliminating temperature-caused measurement error is finally proposed. Correlation models between camera parameters and temperature are formulated. Thereby, camera parameters under different temperature conditions can be predicted and the camera projective matrix can be updated accordingly. By reconstructing the world coordinates with the updated camera projective matrix, the temperature-caused measurement error is eliminated. A satisfactory performance has been achieved by the proposed approach in eliminating the temperature-caused measurement error.