• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권1호
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• pp.7-12
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• 1999

In this paper, the analytical results on the maximum temperature rise estimation, taking account of the magnetizing current, are presented. Magnetizing current effects are considered for the maximum temperature rise estimation during quenches. By introducing the first order model of the infinite solenoids, we calculate the magnetizing and leakage inductances of the coaxial-wound-superconducting transformers. As the permeability of the transformer core increases, so does the magnetizing inductance, while the leakage inductances and the magnetizing current of the transformer go down. These varying permeability effects on maximum temperature rise estimation is applied to the superconducting transformers, of which specifications have already been published. The calculated results showed sufficient margins to the thermal damage.

• 대한기계학회논문집
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• 제14권2호
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• pp.358-366
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• 1990

As a basic study to clarify the scoring resistance in lubricated sliding contact, the temperature rise on frictional surface was analyzed by theoretical method and the effects of various factors on the temperature rise were examined. On the basic of the results obtained theoretically, the practical equations to calculate the maximum average temperature of the contact surface were proposed which are applicable to sliding contact. Then, the effects of sliding velocity and oil temperature on the seizure behavior, and the relation between seizure and temperature rise were investigated. The following conclusions are deduced : The maximum average temperature rise and the other bulk temperature. The former is affected by the size of heat supply region and the sliding velocity, the latter is affected by heat transfer coefficient. Without regard to the operating condition such as sliding velocity, oil temperature and operating time at each load-step, the maximum average temperature just before seizure is nearly constant except in the region of lower velocity. Consequently, the maximum average temperature of the contact surface in boundary lubrication is a useful criterion to predict the scoring of sliding contact.

• 한국구조물진단유지관리공학회 논문집
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• 제5권4호
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• pp.121-129
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• 2001

The semi-adiabatic temperature rise and the losses of temperature of cement paste, mortar and concrete were measured by an apparatus of semi-adiabatic temperature. Heat of hydration was measured by a conduction calorimeter and adiabatic temperature rise of concrete was measured by an adiabatic calorimeter. The derived equation which can assume the adiabatic temperature was proposed by measuring the semi-adiabatic temperature of concrete. The maximum adiabatic temperature rise of concrete obtained by the derived equation of adiabatic temperature, $T_{ad}(t)=T_{sad}(t)+T_{dis}(t)$, showed $55^{\circ}C$ approximately and it had good relation with the other one obtained by the heat of hydration of cement paste and with maximum value which was measured by the adiabatic calorimeter. The adiabatic temperature rise obtained by derived equation was a different information in comparison with the value obtained by adiabatic temperature rise equations by Hell and et. al. in early age, but it showed similar tendencies with the other one according to elapsed time. Adiabatic temperature rise of lich mix concrete with highly cement content was predicted. The adiabatic temperature rise of cement paste and mortar obtained by derived equation from us showed comparatively matching results to compared with that of obtained by adiabatic temperature equation from concrete standard specification.

• 대한치과기공학회지
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• 제35권2호
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• pp.127-136
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• 2013

Purpose: In order to find out the impact of changes in polymerization conditions of orthodontic acrylic resin on maximum load. Methods: While maintaining mixing ratio 3:1 of polymer and monomer in spray-on way in the production condition of polymerization temperature $25^{\circ}C$ or $37^{\circ}C$ for 10 minutes or 30 minutes of polymerization time by pressure $3kfg/cm^2$ or $6kfg/cm^2$ in the lab maintaining $25^{\circ}C$ of room temperature, the change in maximum load rise rate was tested by producing 5 acrylic resin specimens for orthodontics per group to meet the standards of $25mm{\times}2mm{\times}2mm$ and using INSTRON with the 3rd bar 2mm in diameter and parallel support bending device of $15{\pm}0.1mm$ as test equipment showing 30.00mm/min of crosshead speed, $50{\pm}16$ N/min of load ratio in the laboratory of $24^{\circ}C$ room temperature and as a result, the following results were obtained. Results: 1. When increasing pressure from $3kfg/cm^2$ to $6kfg/cm^2$, maximum load was lowered by -4.285%. 2. When increasing polymerization time from 10 minutes to 30 minutes, maximum load rose by 3.848%. 3. When increasing polymerization temperature from $27^{\circ}C$ to $37^{\circ}C$, maximum load rose by 5.854%. Conclusion: Considering the above test results that polymerization time and polymerization temperature when polymerizing acrylic resin for orthodontics according to changes in working conditions had an impact on the rate of rise of maximum load values but the rate of rise was lowered when increasing pressure from $3kfg/cm^2$ to $6kfg/cm^2$, we came to a conclusion that high pressure more than necessary does not affect the rate of rise of maximum load.

• Journal of Welding and Joining
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• 제21권3호
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• pp.68-77
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• 2003

It is important to understand the characteristics of material strength and fracture under the dynamic loading like as earthquakes to assure the integrity of welded structures. The characteristics of dynamic strength and fracture in structural steels and their welded joints should be evaluated based on the effects of the strain rate and the service temperature. It is difficult to predict or measure temperature rise history with the corresponding stress-strain behavior. In particular, material behaviors beyond the uniform elongation can not be precisely evaluated, though the behavior at large strain region after the maximum loading point is much important for the evaluation of fracture. In this paper, the coupling phenomena of temperature and stress-strain fields under the dynamic loading was simulated by using the finite element method. The modified rate-temperature parameter was defined by accounting for the effect of temperature rise under the dynamic deformation, and it was applied to the fully-coupled analysis between heat conduction and thermal elastic-plastic behavior. Temperature rise and stress-strain behavior including complicated phenomena were studies after the maximum loading point in structural steels and their undermatched joints and compared with the measured values.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2009년도 정보통신설비 학술대회
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• pp.391-394
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• 2009

In this paper, achieved rise temperature distribution about degradation phenomenon of 2 MVA distribution mold transformer using finite element method (FEM). Usually, life of transformer is depended on temperature distribution of specification region than thermal special quality of transformer interior. Specially, life of transformer by decline of dielectric strength decreases rapidly in case rise by strangeness transformer interior hot spot temperature value permits. Because calculating high-voltage winding and low-voltage winding of mold transformer and Joule's loss of core for improvement these life, forecasted heat source, and high-voltage winding and low-voltage winding of mold transformer and rise temperature distribution of core for supply of electric power and temperature distribution of highest point on the basis of the result Also, calculated temperature rise limit of mold transformer and permission maximum temperature using analysis by electron miracle heat source alculate and forecasted rise temperature distribution by heat source of thermal analysis with calculated result.

• 콘크리트학회논문집
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• 제27권3호
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• pp.265-272
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• 2015

본 연구에서는 매스콘크리트의 높은 수화열을 제어하기 위하여 결정핵 (C-S-H)와 지연제(포도당)를 동시 사용하여 최대 수화온도를 낮추면서, 응결지연효과를 상쇄시키는 방법이 제시되었다. 이를 위하여 시멘트 페이스트의 수화온도를 측정하고, C-S-H와 포도당의 동시 사용이 시멘트 모르타르의 응결시간 및 압축강도에 미치는 영향을 조사하였다. 실험결과에 따르면. 칼슘실리케이트 수화물과 포도당을 동시 사용할 경우 최대 수화온도를 저감하면서도 최대수화온도에 도달하는 시간을 줄일 수 있음을 확인하였다. 또한 C-S-H와 포도당의 동시 사용은 시멘트 모르타르의 28일 압축강도에는 큰 영향을 미치지 않는 것으로 나타나, 이러한 방법이 매스콘크리트의 수화열 조절에 효과적인 대안이 될 수 있음을 알 수 있었다.

• 전기학회논문지P
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• 제64권4호
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• pp.256-260
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• 2015

In this paper, achieved rise temperature distribution about degradation phenomenon of 24 MVA distribution cast resin transformer using CFD(Computational Fluid Dynamics). Usually, life of transformer is depended on temperature distribution of specification region than thermal special quality of transformer interior. Specially, life of transformer by decline of dielectric strength decreases rapidly in case rise by strangeness transformer interior hot spot temperature value permits. Because calculating high-voltage(HV) winding and low-voltage(LV) winding of cast resin transformer and Joule's loss of core for improvement these life, forecasted heat source, and HV winding and LV winding of cast transformer rise temperature distribution of core for supply of electric power and temperature distribution of highest point on the basis of the results. Also, calculated temperature rise limit of cast resin transformer and permission maximum temperature using analysis by electromagnetic heat source. Calculated and forecasted rise temperature distribution by heat source of thermal analysis with calculated result.

• Journal of Electrical Engineering and Technology
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• 제8권2호
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• pp.339-344
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• 2013

This research deals with design of the maximum thrust density with considering winding temperature rise of single-sided PMLSM. The temperature rise of winding which caused to machine characteristics such as copper loss, iron loss and efficiency was analyzed by FEM. The maximum allowable current density was calculated within the allowable temperature. The effects of loss and efficiency according to temperature characteristic were confirmed.

• Journal of Power Electronics
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• 제13권6호
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• pp.1080-1089
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• 2013

In this paper, the superposition principle of a heat sink temperature rise is verified based on the mathematical model of a plate-fin heat sink with two mounted heat sources. According to this, the distributed coupling thermal impedance matrix for a heat sink with multiple devices is present, and the equations for calculating the device transient junction temperatures are given. Then methods to extract the heat sink thermal impedance matrix and to measure the Epoxy Molding Compound (EMC) surface temperature of the power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) instead of the junction temperature or device case temperature are proposed. The new thermal impedance model for the power converters in Switched Reluctance Motor (SRM) drivers is implemented in MATLAB/Simulink. The obtained simulation results are validated with experimental results. Compared with the Finite Element Method (FEM) thermal model and the traditional thermal impedance model, the proposed thermal model can provide a high simulation speed with a high accuracy. Finally, the temperature rise distributions of a power converter with two control strategies, the maximum junction temperature rise, the transient temperature rise characteristics, and the thermal coupling effect are discussed.