• Title/Summary/Keyword: 시험 온도

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The verified results of arc phenomena when malfunctions occur inside 170kV GIS (170kV GIS의 내부고장 ARC 상태 시험결과)

  • Jeon, Sang-Dong;Kim, Do-Won;Lee, Bong-Hee
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.492-494
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    • 2011
  • 전력설비 증가와 더불어 GIS 사용이 확대되고 있는 상황에서 GIS 내부고장 발생시 복구 지연으로 인한 사례가 지속 발생하고 있다. 이를 예방하기 위해 170kV GIS 고장구간 판정시스템용 압력센서를 개발하고 검증을 위해 실사용 GIS 2대를 이용하여 내아크 시험을 수행한 결과이다. 시험을 통해 고장시 GIS 탱크 내부의 압력, 온도, 압력파를 측정하였고 SF6 Gas 배관과 연결된 현장조작함(LCP)내 가스주입구에 설치한 압력센서의 동작유무을 검증하였다. 시험결과 유동해석(CFD) 등 시뮬레이션 예측보다 압력 및 온도 상승이 높게 측정되었고 제품에 대한 신뢰성과 확대적용 가능성을 확인할 수 있었다.

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Monitoring of Fill Dams for Internal Defect via Centrifuge Model Tests (원심모형시험을 이용한 필댐 취약부 모니터링)

  • Choo, Yun Wook;Cho, Sung Eun;Shin, Dong Hoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.2C
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    • pp.37-47
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    • 2012
  • In this study, three centrifuge tests were performed to evaluate the feasibility of three physical quantities for detecting internal defect of earth core fill dam: pore water pressure, temperature, and electrical resistance. For this purpose, the measurement system for pore water pressure, temperature and electrical resistance on centrifuge model dams was established. Three centrifuge tests included a fill dam without internal defect and two other dams with artificial internal defect in the core. The effectiveness of seepage monitoring was examined during the centrifuge test. Test results showed the applicability of monitoring techniques to detect internal defect by monitoring pore water pressure, temperature, and electrical resistance.

Equipment for Measuring the Adiabatic Temperature Rise of Concrete by Compensating Heat Loss (열손실량 보정을 통한 콘크리트 단열온도상승량 예측 장치)

  • Jin, Eun-Woong;Kim, Chin-Yong;Kim, Jin-Keun
    • Journal of the Korea Concrete Institute
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    • v.24 no.5
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    • pp.535-542
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    • 2012
  • Adiabatic temperature rise test for predicting heat of hydration in mass concrete is especially inconvenient in the field. In order to overcome the problem, the equipment to effectively and conveniently measure semi-adiabatic temperature change was developed. The main objective of this paper is to propose a new and simple equipment for measuring semi-adiabatic temperature rise by using insulation bottles. In order to predict exact heat loss of concrete using this device, it is required to assume the specific heat loss coefficient of the device by water temperature change inside the experimental device. According to experimental and analytical results, the adiabatic temperature rise does not have significant differences in changes of temperature and humidity of air, as well as initial temperature of water. By comparing adiabatic temperature rise tests, the equipment for measuring semi-adiabatic temperature change can be used to predict the hydration heat of concrete within sufficient accuracy.

Effect of Temperature and Day-length on Antioxidants in Sesame (온도와 일장이 참깨의 항산화성분에 미치는 영향)

  • Ryu, Su-Rno;Lee, Jung-Il;Lee, Hyo-Sung
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.38 no.4
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    • pp.330-335
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    • 1993
  • Sesame cultivars were treated with temperature and daylength to determine the environmental variance of Antioxidant content The experiment was performed in phytotron with 11, 13, 15hours of daylength and 20/15, 25 120, 30/25$^{\circ}C (day / night) of temperature treatment. Varietal differences of antioxidant content were significant by the temperature and daylength treatment. Antioxidant content was incrased at higher temperature(25/2$0^{\circ}C$, 30/25$^{\circ}C) and daylength(13hours) but decreased at lower temperature (20/15$^{\circ}C), short daylength (l1hours) and long day length (15hours) condition. Sesamin content were showed 0.06% difference as maxium by the temperature treatment, while 0.03% by the daylength treatment. Sesamolin content were showed 0.03% difference as maxium by the temperature treatment, while 0.01% by the daylength treatment. The antioxidant content was influenced by the increased temperature than daylength.

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Inherent and Interfacial Evaluation of Fibers/Epoxy Composites by Micromechanical Tests at Cryogenic Temperature (극저온에서의 미세역학시험법을 이용한 섬유/수지 복합재료의 계면 특성 평가)

  • Kwon, Dong-Jun;Wang, Zuo-Jia;Gu, Ga-Young;Um, Moon-Gwang;Park, Joung-Man
    • Composites Research
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    • v.24 no.4
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    • pp.11-16
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    • 2011
  • Retention of interfacial shear strength (IFSS) of polymer composites at cryogenic temperature application is very important. In this work, single carbon tiber reinforced epoxy compositc was used to evaluate IFSS and apparent modulus under room and cryogenic temperatures. The property change of carbon and selected epoxy for particularly cryogenic temperature application were tested in tension and compression. Tensile strength and elongation of carbon fiber decreased at cryogenic temperature, whereas tensile modulus was almost same. On the other hand, epoxy matrix showed the increased tensile strength but decreased elongation. It can be due to maximum thermal contraction existing free volume in cryogenic temperature. IFSS increased up to $-10^{\circ}C$ and then decreased steadily. However, IFSS at cryogenic temperature was still similar to that at room temperature. This result is very useful to cryogenic application since selected epoxy toughness and interfacial adhesion can keep at such low temperature.

Evaluation of Physical Properties and Long-term Stability of Expansion Materials for Emergency Repair by Temperature (긴급복구용 팽창재료의 온도에 따른 물리적 특성 및 장기 안전성 평가)

  • Park, Jeongjun;Kim, Kisung;Kang, Hyounhoi;Kim, Ju-Ho;Hong, Gigwon
    • Journal of the Society of Disaster Information
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    • v.14 no.1
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    • pp.79-88
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    • 2018
  • In this study, the changes of the expansion and strength according to the temperature of the emergency repairing expansion material were examined by cup foaming test and uniaxial compressive strength test, and the accelerated compression creep test was carried out to confirm the long term stability. Ramp & Hold test and accelerated compressive creep test were performed to evaluate the creep performance. The short - term creep test was used to determine the initial creep strain of the expanding material. The isothermal method using time - To evaluate the long - term compressive creep performance.

Development Test of Pyro-Valve for Cryogenic Gaseous Helium in Pressurization System of Launch Vehicle (발사체 가압시스템용 극저온 헬륨가스 파이로밸브 개발시험)

  • Chung, Yong-Gahp;Han, Sang-Yeop;Cho, In-Hyun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.293-297
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    • 2009
  • Valves, which are used to supply or block the flow of cryogenic pressurant in the pressurization system of liquid-propellant propulsion system in a launch vehicle, are pneumo-actuated valve, solenoid valve, pyro-valve, etc. Both pneumo-actuated valve and solenoid valve have more complex structure and are heavier than pyro-valve. For this study, a couple of pyro-valves, which are applicable to cryogenic and high-pressure fluid (cryogenic gaseous helium), have a simple structure, and are comparably light, are designed, manufactured, and tested (proof-pressure/leakage tests, performance test, vibration test, helium supply tests).

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Infrared Thermographic Monitoring for Failure Characterization in Railway Axle Materials (철도차량 차축 재료의 파괴특성 적외선열화상 모니터링)

  • Kim, Jeong-Guk
    • Journal of the Korean Society for Nondestructive Testing
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    • v.30 no.2
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    • pp.116-120
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    • 2010
  • The wheelset, an assembly of wheel and axle, is one of important parts in railway bogie, directly related with the running safety of railway rolling stock. In this investigation, the tensile failure behavior of railway axle materials was investigated. The tensile coupons were prepared from the actual rolling stock parts, which were operated over 20 years. The tensile testing was performed according to the KS guideline. During tensile testing, an infrared camera was employed to monitor temperature changes in specimen as well as demonstrate temperature contour in terms of infrared thermographic images. The thermographic images of tensile specimens showed comparable results with mechanical behavior of tensile materials. In this paper, the failure mode and behavior of railway axle materials were provided with the aid of infrared thermography technique.

Development of Decompressed Dryer for Mushroom (버섯의 감압건조기 개발)

  • 김영민;김유호;조영길;최희석;조광환
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2003.07a
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    • pp.267-272
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    • 2003
  • 본 연구에서는 버섯의 건조시간을 줄여 건조 후 버섯의 품질을 향상시키기 위하여 버섯의 감압건조기를 개발하였으며 연구 결과는 다음과 같다. 가. 버섯의 감압건조기의 시작기를 제작하였고, 시작기의 구조는 건조실, 감압블로워, 흡ㆍ배기구 솔레노이드 밸브, 제습장치, 송풍기, 전기히터로 구성되어 있으며, 건조실의 내부 압력이 표준대기압-900hPa, 열풍온도는 상온에서 5$0^{\circ}C$까지 조절할 수 있도록 제작하였다. 나. 시작기를 이용하여 표고버섯을 대상으로 건조특성시험을 실시한 결과, 열풍온도 5$0^{\circ}C$, 건조실 내부압력 900-940hPa에서 건조시간은 11.5h으로 대기압과 비교하여 6.5h 단축되는 것으로 나타났다. 또한, 건조 전ㆍ후의 색차, 수축률, 복원률의 품위가 우수한 것으로 나타났으며 F-test 유의성 검증 결과, 5%의 유의수준에서 갓주름의 색차, 갓직경의 수축률, 복원률에서 유의차가 있는 것으로 나타났다. 다. 열풍온도 5$0^{\circ}C$, 건조실 내부압력 900-940hPa로 표고버섯과 아가리쿠스에 대하여 건조성능시험을 실시한 결과, 표고버섯의 경우 건조시간은 13h으로 열풍식 농산물 건조기와 비교하여 건조시간이 4.5h 단축되는 것으로 나타났으며, 아가리쿠스의 경우 건조시간이 17.5h로 나타났다. 라. 성능시험 결과, 시작기가 열풍식 농산물건조기와 비교하여 건감률, 색택, 수축률, 복원률 등의 품위가 전반적으로 우수한 것으로 나타났다. 마. 시작기의 건조비용을 분석한 결과, 건조시간은 단축되었지만 시설투자비가 높아 건조비용이 표고버섯의 경우 2,461원/kg으로 열풍식 농산물건조기 보다 13% 높은 것으로 나타났지만, 추후 고품질 건조버섯 생산을 위한 기초자료로 활용이 가능할 것으로 판단된다.라갈수록 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.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all

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Preliminary Thermal Analysis for LEO Satellite Optical Payload's Thermal Vacuum Test (저궤도위성 광학탑재체의 지상 열진공 시험을 위한 예비 열해석)

  • Lee, Jongl-Yul;Huh, Hwan-Il;Kim, Sang-Ho;Chang, Su-Young;Lee, Deog-Gyu;Lee, Seung-Hoon;Choi, Hae-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.39 no.5
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    • pp.466-473
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    • 2011
  • The purpose of satellite thermal control design is to maintain all the elements of a spacecraft system within their temperature limits for all mission phases. The thermal analysis model for Low Earth Orbit satellite payload level simulation is established by considering thermal vacuum test environment condition, thermal vacuum chamber configuration, and satellite's payload inner thermal environment. The established thermal analysis model is used to determine thermal vacuum test conditions and test case requirements.