• Title/Summary/Keyword: 손상공기

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트럭 ㆍ버스용 타이어의 블리딩 C.B.U.

  • Lee, Gwang-Jae
    • The tire
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    • s.132
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    • pp.23-39
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    • 1987
  • 타이어는 여러가자의 중요한 기능을 갖추고 있으나 공기압이 부족하거나 또는 공기가 누출된 상태에서 사용하여 타이어가 손상된 경우에는 자동차의 조종성, 안정성에 중대한 영향이 미친다는 것은 명백한 사실이다. 이러한 타이어 손상의 일례로서 트럭ㆍ버스용 타이어의 블리딩(bleeding) C.B.U.가 있다. 본고는 이와같은 손상에 대하여 실제 사용조건에서 재현 테스트를 실시하여 그 발생요인을 해석한 일본 자동차 타이어 협회의 자료에서 발췌한 것이다.

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High-Temperature Design of Sodium-to-Air Heat Exchanger in Sodium Test Loop (소듐 시험루프 내 소듐대 공기 열교환기의 고온 설계)

  • Lee, Hyeong-Yeon;Eoh, Jae-Hyuk;Lee, Yong-Bum
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.5
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    • pp.665-671
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    • 2013
  • In a Korean Generation IV prototype sodium-cooled fast reactor (SFR), various types of high-temperature heat exchangers such as IHX (intermediate heat exchanger), DHX (decay heat exchanger), AHX (air heat exchanger), FHX (finned-tube sodium-to-air heat exchanger), and SG (steam generator) are to be designed and installed. In this study, the high-temperature design and integrity evaluation of the sodium-to-air heat exchanger AHX in the STELLA-1 (sodium integral effect test loop for safety simulation and assessment) test loop already installed at KAERI (Korea Atomic Energy Research Institute) and FHX in the SEFLA (sodium thermal-hydraulic experiment loop for finned-tube sodium-to-air heat exchanger) test loop to be installed at KAERI have been performed. Evaluations of creep-fatigue damage based on full 3D finite element analyses were conducted for the two heat exchangers according to the high-temperature design codes, and the integrity of the high-temperature design of the two heat exchangers was confirmed.

Air-liquid Flow Characteristics of Riser of Air-lift Pump (공기양수펌프 Riser 내의 기액유동특성)

  • Lee, Cheol-Hee;Cho, Dae-Hwan;Choi, Ju-Yeol;Park, Chan-Soo
    • Proceedings of KOSOMES biannual meeting
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    • 2006.11a
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    • pp.239-244
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    • 2006
  • As an effective means to convey crushed materials from seabed to onboard ship, air-lift pump provides a reliable mechanism due to its simple configuration and easy-to-operate principle. The present study is focused on fundamental investigation of related performance through analysis program based on the gas-liquid two-phase flow in circular pipes. It is summarized as important result that an optimum air mass flow rate exists for the maximum lifted liquid mass flow rate in terms of a given submergence rates.

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A Study on the Condensation Prevention of Bulk Carrier (화물선의 결로 방지에 대한 연구)

  • Oh, Sae-Gin;Kim, Won-Ouk;Kim, Seung-Hwan;Lee, Seung-Geun;Kim, Jong-Su
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.17 no.4
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    • pp.429-434
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    • 2011
  • Bulk cargo loaded into ship can be damaged by various kinds reasons. This paper aims to analyze about cargo damage of coil carrier ship due to condensation. Condensation is the formation of liquid drops of water from water vapor. Condensation consists of small drops of water which form when warm water vapour or steam touches a cold surface such as a window. In general, condensation have occurred by temperature difference at large building and ship's tank. It is phenomenon that can occur often to oceangoing vessel moving temperature difference places in similar time. This paper proposes a new method using dehumidification device and fan heater to prevent bulk cargo damage of coil carrier ship from condensation.

Two Cases of Pneumatic Tourniquet Paralysis: Points for Prevention (공기주입 구혈대로 인한 상지마비 2예: 예방을 위한 수칙)

  • Kim, Hyonsurk;Kim, Young Ho
    • Archives of Hand and Microsurgery
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    • v.23 no.4
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    • pp.313-318
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    • 2018
  • Although nerve injury is the most common complication of pneumatic tourniquets, it is said to be rare, with few case reports. We describe two cases of paralysis after upper extremity surgery to highlight this risk. Ulnar, median and radial neuropathies were diagnosed after surgery was performed on a man for left hand reconstruction, presumably due to a prolonged total inflation time of 14 hours despite conventional break times. A woman who received surgery for a crushed hand presented with radial neuropathy, the most probable cause being malfunction and automatic inflation of the tourniquet. These cases illustrate the diversity of tourniquet paralysis, with symptomatic progress not necessarily following electromyography results. The considerable discomfort to patients warrants careful use of tourniquets for neuropathy prevention.

Experimental Study of Freezing and Thawing Characteristics of Concrete Influenced by Air Content and Water Cement Ratio. (공기량 및 물-시멘트비에 따른 콘크리트의 동결융해 특성에 관한 실험적 연구)

  • 오병환;한승환;이용호
    • Proceedings of the Korea Concrete Institute Conference
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    • 1993.10a
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    • pp.91-96
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    • 1993
  • 본 연구의 목적은 콘크리트의 열화손상을 주는 요인 중 특히 수분의 공급이 충분한 동결융해작용에 대한 영향인자에 대한 실험적 연구이다. 콘크리트의 열화에 영향을 주는 여러 영향인자 중에서 주로 공기량 및 물-시멘트비를 다루었다.

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Technology of Minimized Damage during Loading of a Thin Wafer (박판 웨이퍼의 적재 시 손상 최소화 기술)

  • Lee, Jong Hang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.1
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    • pp.321-326
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    • 2021
  • This paper presents a technique to minimize damaged wafers during loading. A thin wafer used in solar cells and semiconductors can be damaged easily. This makes it difficult to separate the wafer due to surface tension between the loaded wafers. A technique for minimizing damaged wafers is to supply compressed air to the wafer and simultaneously apply a small horizontal movement mechanism. The main experimental factors used in this study were the supply speed of wafers, the nozzle pressure of the compressed air, and the suction time of a vacuum head. A higher supply speed of the wafer under the same nozzle pressure and lower nozzle pressure under the same supply speed resulted in a higher failure rate. Furthermore, the damage rate, according to the wafer supply speed, was unaffected by the suction time to grip a wafer. The optimal experiment conditions within the experimental range of this study are the wafer supply speed of 600 ea/hr, nozzle air pressure of 0.55 MPa, and suction time of 0.9 sec at the vacuum head. In addition, the technology improved by the repeatability performance tests can minimize the damaged wafer rate.

Boron-Containing Solid Fuel Combustion and Cycle Analysis (보론을 포함한 고체 연료 연소와 사이클 해석)

  • Lee, Tae Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.1
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    • pp.18-24
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    • 2015
  • An experimental investigation was conducted to figure out the effects of the inlet air temperature on the combustion efficiency using the fuel grains which were highly loaded with boron carbide. The results showed that the normalized combustion efficiency increased with the inlet air temperature, apparently the result of enhanced combustion of the boron particles. Even though the combustion efficiency is increased, the overall efficiency through the semi-empirical method, is decreased with the increasing inlet air temperature. Brayton cycle analysis has been performed using the heat input parameter and combustor Mach number, those two parameters are important role for the performance and similar trends are shown at the experimental results.