• Title, Summary, Keyword: Thermal deterioration

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A Study on the Debonding Phenomena of Clad Steel(1) -Deterioration of Interfacial Strength in Clad Steel by Thermal Treatment- (CLAD강의 DEBONDING 현상에 대한 연구(1) -열처리에 의한 clad강 계면의 강도 약화-)

  • 윤중근;김희진
    • Journal of Welding and Joining
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    • v.5 no.3
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    • pp.28-37
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    • 1987
  • To clarify the debonding phenomena of clad steel, the effect of thermal treatment (temperature, holding time) on the interfacial strength of clad steel was preliminarily investigated. From this study, it was confirmed that the interfacial strength of clad steel was deteriorated by thermal treatment and the amount of strength deteriorated, depending on the condition of thermal treatment, could be evaluated by the following equation. ${\sigma}_{ HT}/{\sigma}_{i}/=A_{0}-A\;exp(-Q/RT)log(t/t_{0})$ This equation implies that temperature has a far strong effect on strength deterioration than tiem. The deterioration of interfacial strength of clad steel after thermal treatment may be derived from the thermal stress caused by the difference in thermal expansion coefficient between component materials and microstructural change along the interface.

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Development of Fuzzy Inference-based Deterioration Diagnosis System Using Infrared Thermal Imaging Camera (적외선 열화상 카메라를 이용한 퍼지추론 기반 열화진단 시스템 개발)

  • Choi, Woo-Yong;Kim, Jong-Bum;Oh, Sung-Kwun;Kim, Young-Il
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.64 no.6
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    • pp.912-921
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    • 2015
  • In this paper, we introduce fuzzy inference-based real-time deterioration diagnosis system with the aid of infrared thermal imaging camera. In the proposed system, the infrared thermal imaging camera monitors diagnostic field in real time and then checks state of deterioration at the same time. Temperature and variation of temperature obtained from the infrared thermal imaging camera variation are used as input variables. In addition to perform more efficient diagnosis, fuzzy inference algorithm is applied to the proposed system, and fuzzy rule is defined by If-then form and is expressed as lookup-table. While triangular membership function is used to estimate fuzzy set of input variables, that of output variable has singleton membership function. At last, state of deterioration in the present is determined based on output obtained through defuzzification. Experimental data acquired from deterioration generator and electric machinery are used in order to evaluate performance of the proposed system. And simulator is realized in order to confirm real-time state of diagnostic field

Study on Long-term Deterioration Properties of Porcelain Insulators with Aluminous System (알루미나계 자기애자의 장기 피로특성에 관한 연구)

  • Han, Se-Won;Cho, Han-Goo;Lee, Dong-Il;Cho, In-Hyuk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.562-563
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    • 2005
  • In case of aged porcelain, the failure in basic performance tests happened in cool-heat tests. Based on this characteristic, we studied the method predicting failure phenomena through more severe accelerated cool-heat ageing and accelerating thermal mechanical performance tests. Test results indicated that the thermal stress by temperature gradient was more severe parameter than thermal stress by quenching cycles within a category of standard or accelerating methods. And there is no the deterioration of statistic strength, but the deterioration of strength according to accelerating tests is serious.

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Effects of Selected Stabilizers on the Color Deterioration of Crude Pigment Extract from Schizandra fruit (Schizandra Fructus) (여러 가지 안정화 물질이 오미자 색소 추출물의 가열 변색에 미치는 영향)

  • Kim, Hyun-Jung;Cho, Sung-Bin;Chun, Hyang-Sook
    • Journal of the Korean Society of Food Culture
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    • v.18 no.5
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    • pp.475-482
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    • 2003
  • The effects of selected stabilizers and sugars on color deterioration of anthocyanin in Schizandra fructus were examined at $100^{\circ}C$ for $120{\sim}180$ min. Among four test sugars, it was found that fructose accelerated the thermal color deterioration while maltose retarded the color deterioration by 40%. Maltodextrin and ${\gamma}$-cyclodextrin showed the highest stabilizing effect on the thermal color deterioration of crude pigment extract from Schizandra fructus(CPES) containing 2 mg% of anthocyanin. Addition of maltodextrin or ${\gamma}$-cyclodextin at 5% retarded thermal color deterioration of CPES. In gel system, 5% of maltodextrin also retarded the color deterioration by $15{\sim}20%$ during storage at $25^{\circ}C\;and\;35^{\circ}C$.

A Study on Chemical Characteristic of Electrically and Thermally Treated MPPF Capacitor Elements (MPPF 커패시터의 전기적, 열적 열화시 소체의 화학적특성에 관한 연구)

  • Koo, Kyo-Sun;Song, Hyun-Seok;Lee, Dong-Zoon;Kwak, Hee-Ro;Shong, Kil-Mok
    • Proceedings of the KIEE Conference
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    • pp.227-230
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    • 2001
  • This paper divides the factors of an accident into two parts, that are electrical deterioration and thermal deterioration, to analyze a characteristic of the factor of an accident which can break out in the capacitor of metal vaporized polypropylene film. For the purpose of creating capacitor which is caused by electric deterioration, we applied DC overvoltage, induced self-healing and breakdown from element. We applied gradual heat to get an element which is cause by thermal deterioration. The chemical structure of the shape and surface is analyzed by thermogravimetric analyzer (TGA), Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectrometer(FT-IR). As a result, the peak of methylene group came out, in case of electrical deterioration, as observing the self-healing point. However, the peak is disappeared in the heat treated element by 500[$^{\circ}C$], and the peak of carbonyl group which has C=O came out in case of thermal deterioration.

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Use of Nisin as an Aid in Reduction of Thermal Process of Bottled Sikhae (Rice Beverage)

  • Yoo, Jin-Young;Kwon, Dong-Jin;Park, Jong-Hyun;Koo, Young-Jo
    • Journal of Microbiology and Biotechnology
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    • v.4 no.2
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    • pp.141-145
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    • 1994
  • Conventional commercial thermal process for preparing Sikhae (Rice beverage) in a hermetically sealed container was evaluated to solve the nutritional deterioration and organoleptic inferiority problem caused by severe heat treatment. A milder thermal process with an aid of Nisin, a GRAS-grade, selectively germicidal compound, was introduced to destroy the putrefactive microorganisms. In this experiment, hot-filling method with Nisin, and thermal processing (at 110$^{\circ}C$ for 15 minutes with Nisin, at 121$^{\circ}C$ for 25 minutes without Nisin) were compared. The quality of Sikhae could be enhanced and over 90% of the thermal process could be conserved by this process in terms of sterilizing value without quality deterioration when processing the bottled Sikhae at 110$^{\circ}$ for 15 minutes $\{(F^{10}{_{121})_{process}=1.54\}$.

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Implementation of Prediction Program for Deterioration Judgment on Substation Power Systems in Urban Railway (도시철도 전력설비의 노후화 판단을 위한 예측 프로그램 구현)

  • Jung, Ho-Sung;Park, Young;Kang, Hyun-Il
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.6
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    • pp.881-885
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    • 2013
  • In this paper, we present a deterioration judgment model of urban rail power equipment using driving history, the frequency and number of failures. In addition, we have developed a deterioration judgment program based on the derived failure rate. A deterioration judgment model of power equipments on metro system was designed to establish how much environmental factors, such as thermal cycling, humidity, overvoltage and partial discharge. The deterioration rate of the transformers followed the Arrhenius log life versus reciprocal Kelvin temperature (hotspot temperature) relation. The deterioration judgment program is linked to the online condition monitoring system of urban railway system. The deterioration judgment program is based on the user interface it is possible to apply immediately to the urban rail power equipment.

A Composite Camera Calibration Technique for Thermal Deterioration Diagnosis of Power Distribution Line (배전 선로의 열화 진단을 위한 복합 카메라 보정기법)

  • Jung, Ha-Hyoung;Park, Jin-ha;Lyou, Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.6
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    • pp.463-469
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    • 2016
  • This paper presents a composite camera calibration method to determine thermal degradation of power distribution equipment by combining an infrared (IR) camera and a color camera. A calibration jig was first constructed to match the properties of the two cameras. Our calibration and visualization techniques allow for the display of two images, one from the color camera and the other from the IR camera with different field of views (FOVs), on the screen at the same time. To confirm its validity, several case studies have been developed to analyze thermal deterioration limits of indoor and outdoor power distribution facilities.

Shrinkage rate and Structure analysis of IV according to Thermal deterioration (열열화 온도에 따른 IV의 수축률 및 조직분석)

  • Choi, Chung-Seog;Kim, Hyung-Rae;Song, Kil-Mok;Kim, Hyang-Kon;Kim, Dong-Ook;Kim, Dong-Woo
    • Proceedings of the KIEE Conference
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    • pp.1416-1418
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    • 2002
  • In order to examine the thermal properties of the wire materials, we analyzed the shrinkage, the expansion and the form transformation, the surface structure according to the thermal deterioration temperature through the testing method for a heating shrinkage of Korean Industrial Standard(KS C 3004). For IV(600V grade polyvinyl chloride insulated wires), we measured the shrinkage and the expansion rate, analyzed the surface structure using SEM(Scanning Electron Microscope). In the result of this experiment, the shrinkage rate of IV 2.0mm covering was high in comparison with other wires. As the deterioration temperature rises gradually, the covering is molten and harden.

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