• Title/Summary/Keyword: Air transport

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Measurement of In-plane Gas Permeability of Gas Diffusion Layers in Proton Exchange Membrane Fuel Cells under Compressive Strain (고분자 전해질 연료전지 가스확산층의 압축상태 평면 기체투과율 측정)

  • Oh, Changjun;Lee, Yongtaek
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.9
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    • pp.367-372
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    • 2016
  • Gas diffusion layer (GDL) of PEMFCs plays a role that it diffuses the reactant gases to the catalyst layer on the membrane and discharge water from the catalyst layer to the channel. Physical parameters related to the mass transport of GDL are mostly from the uncompressed GDLs while actual GDLs in the assembled stacks are compressed. In this study, the relation of compression and strain of GDLs with various Polytetrafluoroethylene (PTFE) loading is measured experimentally and In-plane gas permeability is measured at the condition that the GDLs are in compressive strain. The gas permeability decreased with the loading of PTFE and the presentation of gas permeability under compressive stain is expected to improve the accuracy of modeling work of mass transport in the GDL.

A Study on Risk Factors by Analyzing Human Factors during Air Refueling Missions for Fighter Pilots (전투기 조종사의 공중급유 임무 시 인적요인 분석을 통한 위험요인 연구)

  • Koo, BonEan
    • Korean journal of aerospace and environmental medicine
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    • v.30 no.3
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    • pp.113-129
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    • 2020
  • With the operation of the KC-330 MRTT (Multi Role Tanker Transport), which had been fielded in 2019, the ROKAF (Republic of Korea Air Force) has given fighter pilots a new mission of air refueling. As a result, fighter pilots are more likely to be exposed to risks they have never faced before, and it is necessary to look at the risk factors associated with human factors in air refueling missions. Therefore, in this study, an analysis using the HFACS (Human Factors Analysis and Classification System) model was performed for fighter pilots with air refueling qualifications. This study tried to prevent hazard in advance by discriminating the risk factors according to the human factors related to the fighter pilot during the air refueling mission.

A Study on the Management for Reducing empty truck movements (사업용 화물자동차의 공차운행 감소에 관한 연구)

  • 전만술;김연희
    • Proceedings of the Safety Management and Science Conference
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    • 2002.05a
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    • pp.285-294
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    • 2002
  • This study is focused on the operation of truck with conscious for environmental logistics system to reduce empty truck movements, and to control running empty truck. With the logistics function, road transport represents the biggest environmental threat. Using nonrenewable natural resources, contributing to air and noise pollution, trucks are environmentally unfriendly. Any steps to reduce transport activity will help minimize negative impact. In particular, noxious emissions must be reduced, but in the long term more environmentally friendly vehicles are required.

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The Present State of an Air Pollutants Inflow into Gyeongju and Effects on Stone Cultural Properties (경주권역으로의 대기오염물질 유입현황과 석조문화재에 미치는 영향)

  • Jung, Jong-Hyeon;Shon, Byung-Hyun;Kim, Hyun-Gyu;Choi, Won-Joon;Nam, Chul-Hyun
    • Journal of Environmental Health Sciences
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    • v.31 no.5 s.86
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    • pp.349-359
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    • 2005
  • In this study, we focused on the geographical and the meterological conditions, the atmospheric examination, the soil contents and compositions in order to establish cultural properties conservation plan in Gyeongju and its surroundings. Also, the transport route with environmental contaminants in Ulsan and Pohang was examined. The results could be summarized as follows ; Air pollutant and environmental contaminant was transported by two types of winds. One is induced by local winds, the other is induced by synoptic winds. Air contaminant transported from coastal regions to inland regions were associated with wind velocity. Gyeongju had good atmospheric conditions, i.e. $SO_2\;0.009{\sim}0.011ppm,\;CO\;0.6{\sim}0.8ppm,\;NO_2\;0.015{\sim}0.020ppm,\;O_3\;0.017{\sim}0.032ppm,\;PM_{10}\;46{\sim}62{\mu}g/m^3\;and\;Pb\;0.034{\sim}0.060{\mu}g/m^3$, which was below environmental air qualify standards and was little lower than those of Pohang and Ulsan. However, Ulsan and Pohang city are located on south-east coast and have many industrial facilities. Hence, air pollution problems become serious issues in Ulsan, Pohang, Busan, Daegu and other cities due to the emission of air pollutants from the various industrial facilities, incinerator and power plants, etc. The soil of Gyeongju had heavy metals conditions, i.e. $Cd\;0.01{\sim}0.08mg/kg,\;Cu\;N.D{\sim}2.39mg/kg,\;As\;N.D{\sim}0.07mg/kg,\;Hg\;N.D{\sim}0.15mg/kg,\;Pb\;0.49{\sim}1.39mg/kg,\;Cr^{+6}\;0.02{\sim}0.42mg/kg,\;Fe\;0.74{\sim}1.55mg/kg,\;Mn\;0.11{\sim}0.49mg/kg\;and\;Zn\;1.11{\sim}3.56mg/kg$. However, pH value of soil had range of $4.12{\sim}7.45$. The results showed that high pH concentration of soil could occur due to air pollution diffusion and environmental contaminant transport at Ulsan and Pohang city.

A Commentary on Air Pollution Monitoring Programs in Korea

  • Ghim, Young-Sung;Kim, Jin-Young;Shim, Shang-Gyoo;Moon, Kill-Choo
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.E1
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    • pp.21-28
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    • 2002
  • Air quality issues in Korea rapidly changed at the beginning of the 1990s from primary to secondary pollutants starting in Seoul, the capital of Korea. The present frame of national air pollution monitoring networks was established between the end of the 1980s and the beginning of the 1990s. Background monitoring was initiated in the middle of the 1990s in response to increasing public concern about the long-range transport of air pollutants. Apart from the national monitoring, both routine and intensive measurements of fine particles have been made for research purposes since the middle of the 1990s at several background sites. However, air pollution monitoring in urban areas for other purposes was relatively scarce as national monitoring has been concentrated in these areas. Although ozone pollution has become a significant issue in major metropolitan areas every summer, only a little information on ozone precursors is available. During the past few years, the number of national monitoring stations has greatly increased. The government has a plan to gradually expand monitoring items as well as stations. It is anticipated that highly detailed information on both photochemical reactants and products will be available within the next several years. More emphasis will be placed on toxic substances based on risk assessment in monitoring for both research and policy making.