• Title/Summary/Keyword: grease

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STUDY ON NOISE AND ABRASION OF THE CURVE DEPENDENT WHEEL FLANGE LUBRICATOR WITH CREASE SPRAY TYPE (곡선감지형 그리스 분사식 후렌지 도유기의 소음 및 마모 특성 연구)

  • Yang Bang-Sub;Ro Yang-Hwan;Lee Ju-Ho
    • Proceedings of the KSR Conference
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    • 2003.05a
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    • pp.633-637
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    • 2003
  • In this study, Curve dependent wheel flange lubricator with grease spray type is investigated and estimated a point of view reducing wheel flange wear and noise in the curve through field test. Advantage of curve dependent wheel flange lubricators with grease spray type is found on the basis of the result of field test in comparison with flange lubricator of oil spray type and bogie without wheel flange lubricator on railroad in korea.

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STUDY ON THE CURVE DEPENDENT WHEEL FLANGE LUBRICATOR WITH CREASE SPRAY TYPE (곡선감지형 그리스 분사식 후렌지 도유기에 관한 연구)

  • 이주호;노양환;양방섭
    • Proceedings of the KSR Conference
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    • 2002.10a
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    • pp.188-192
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    • 2002
  • In this study, Curve dependent wheel flange lubricator with grease spray type is introduced and checked and estimated a point of view reducing wheel flange wear and noise in the curve. Advantage of curve dependent wheel flange lubricators with grease spray type is found on the basis of the result of field test applied to KNR No. 1 Line(reconstruction car).

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Interfacial Breakdown characteristics in XLPE/EPDM Laminate (XLPE/EPDM laminate의 절연파괴특성)

  • 남진호;서광석
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.495-497
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    • 1999
  • In order to determine what influences the interfacial breakdown in EPDM/XLPE laminates, We made the breakdown test ceil and this was pressure controllable breakdown test cell. We make the needle electrode (tip radius: about 10 micrometer) using electrochemical method. We studied the interfacial silicone oil was higher than that with silicone grease. As a function of heat treatment time in a vacuum, interfacial breakdown strength increased much in XLPE/EPDM laminates pasted with silicone grease but increased a little in that with silicone oil.

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Chemical Effects to Cement Concrete by Grease Oxidation (그리이스의 산화가 시멘트 콘크리트에 미치는 화학적 영향)

  • 정근우;조원오;김영운;임수진;이은아;김성욱
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.99-105
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    • 2000
  • Greases composed of base oil and thickener are widely used in the purpose of lubrication and anti-corrosion of machinery. However, greases are sometimes oxidized and decomposed by heat of friction, and produced organic acid. And the greases leaked out ordinary spot make the concrete structures weaken. In this study, the chemical effects of the greases with the concrete structures were investigated through oxidation reaction under pressure and oxygen, and evaluated by the analysis of TAN, Ca content, FT-IR and XRD of grease and cement powder after the oxidation reaction. As the results, TAN value decreased with the increase of the content of cement because of neutralization of organic acid produced by the oxidation of grease with calcium contained in the cement. The content of calcium linearly increased with the increase of cement due to calcium salt by neutralization of acid. Also, according to XRD results of the cement powder oxidized at 99 $^{\circ}C$, the diffraction peak due to calcium hydroxide decreased in comparison with that at room temperature because of the reaction of calcium and organic acid.

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Study on Thermal & Optical Properties of LED Street Lighting Module (LED 가로등 모듈의 열적.광학적특성 연구)

  • Oh, Seul-Yi;Jo, Ju-Ung;Gang, Seong-Hui;Lee, Seung-Min;Yang, Jong-Kyung;Lee, Ju-Seong;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.273-274
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    • 2009
  • 현재 가로등의 93.3[%]를 차지하고 있는 나트륨램프는 색상이 적황색이며, 시력에 장애와 피로감을 주어 인체에 해로우므로 고효율 램프로 교체되고 있으며 백열전구는 전력을 많이 소모하고 잦은 고장으로 빈번한 대체와 유지보수를 필요로 하므로 LED를 선택하면, 유지보수 비용과 안전성, 에너지 효율성면에서 큰 강점을 갖는다. 본 연구에서는 에너지 효율이 높은 LED 가로등 제작을 위한 모듈을 제작하여, 열적, 광학적 분석을 하였다. 동작 150분 후, LED Module의 PCB기판 6 Point에서 Thermal Grease와 Thermal Pad의 처리에 의한 열적 변화를 측정하였으며, Thermal Grease 처리는 Thermal Pad 보다 평균 3 $[^{\circ}C]$ 정도 낮은 35 $[^{\circ}C]$결과를 얻었으며, 제작된 LED Module의 광학적평가의 결과는 10 [m] 높이에서 $20\times20\;[m^2]$ 면적에 조사된 조도의 최대,최소값은 10.9~0.6 [lx]이고, 주로 10~5 [lx] 값이 조도의 면적을 차지하였으며, 곡선은 옆으로 넓게 펼쳐진 곡선을 나타내었다.

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Temperature and Leakage Current Characteristics with Structure of Polymeric Surge Arresters (폴리머 피뢰기의 구조에 따른 온도와 누설전류 특성)

  • Cho, Han-Goo;Lee, Un-Yong;Kim, Ha-Na
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.513-514
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    • 2006
  • This paper presents the temperature characteristics with the structure of 18 kV surge arresters for distribution system. Three types of polymer arrester were fabricated and a ceramic arrester was also prepared to investigate. Below $100^{\circ}C$, three types of polymeric arresters exhibited almost the same leakage current value, but above $100^{\circ}C$, the polymeric arresters whose module was injected into polymeric housing with the grease exhibited the highest leakage current. In contrary, the arresters being manufactured by directly injecting silicone rubber onto arrester module exhibited the lowest leakage current. The rapid rising of leakage current of the polymeric arresters with the grease at $120^{\circ}C$ was because of the deterioration of the insulation characteristics of the grease between the FRP module and the silicone housing. All polymeric arresters exhibited the same surface temperature characteristics but the ceramic arresters was slower than the polymer arrester in heat emission despite the lowest leakage current. It was thought that the air layer between ZnO varistor blocks and the ceramic housing prevented the heat emission.

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A study on the heat dissipation characteristic of thermal interface materials with Graphene, Cu and Ag nano powders (Graphene, Cu와 Ag 나노 파우더를 이용한 열전도재의 방열 특성에 관한 연구)

  • Park, Sang-Hyeok;Im, Sung-Hoon;Kim, Hyun-Ji;Noh, Jung-Pil;Huh, Sun-Chul
    • Journal of the Korean Society of Industry Convergence
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    • v.22 no.6
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    • pp.767-773
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    • 2019
  • The thermal diffusion performance of the electronic device is a factor for evaluating the stability of the electronic device. Therefore, many of research have been conducted to improve the thermal characteristics of thermal interface materials, which are materials for thermal diffusion of electronic products. In this study, nano thermal grease was prepared by blending graphene, silver and copper nano powders into a thermal grease, a type of thermal interface materials, and the heat transfer rate was measured and compared for the purpose of investigating the improved thermal properties. As a result, the thermal properties were good in the order of graphene, silver and copper, which is thought to be due to the different thermal properties of the nano powder itself.

Screw Transformation Mechanism of Screw-Propelled Robot for Efficient Void Detection in Grease Pipe (스크류 추진형 검측 로봇의 효율적인 검측을 위한 스크류 구조 변화 메커니즘)

  • Kim, Dongseon;Kim, Hojoong;Kim, Jinhyun
    • The Journal of Korea Robotics Society
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    • v.17 no.2
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    • pp.172-177
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    • 2022
  • In general, detection robots using ultrasonic sensors are equipped with sensors to protrude outward or to contact objects. However, in the case of a screw-propelled robot that detects the inside of a reactor tendon duct, if the ultrasonic sensor protrudes to the outside, resistance due to grease is generated, and thus the propulsion efficiency is reduced. In order to increase the propulsion efficiency, the screw must be sharp, and the sharper the screw, the more difficult it is to apply a high-performance ultrasonic sensor, and the detection efficiency decreases. This paper proposes a screw shape-changing mechanism that can improve both propulsion efficiency and detection efficiency. This mechanism includes an overlapped helical ring (OHR) structure and a magnetic clutch system (MCS), and thus the shape of a screw may be changed to a compact size. As a result, the Screw-propelled robot with this mechanism can reduce the overall length by about 150 mm and change the shape of the screw faster and more accurately than a robot with a linear actuator.