• Title/Summary/Keyword: Air Assist

Search Result 78, Processing Time 0.026 seconds

A Review on Fit Test for Respirators and the Regulations (호흡기보호구의 Fit Test 방법과 규정에 관한 고찰)

  • Han, Don-Hee;Willeke, Klaus;Colton, Craig E.
    • Journal of Korean Society of Occupational and Environmental Hygiene
    • /
    • v.6 no.1
    • /
    • pp.38-54
    • /
    • 1996
  • Respirator fit testing is required before entering specific work environmentals to ensure that the respirator worn satisfies a minimum of fit and that the user knows when the respirator fits properly. The fit of a respirator can be determined by qualitative (QLFT) or quantitative fit test (QNFT). The QNFT, having been universally accepted more than the QLFT, provide an objective and numerical basis by measuring a fit factor (FF). Until a few years age, only one QNFT technigue was available and accepted by U.S. Occupational Safety and Health Administration (OSHA) regulations. In the 1980's and 1990's, several new and fundamentally different QNFT methods were developed. Two of the newer methods are commercially availale and are accepted by OSHA as suitable alternatives. In this articles, the principle of operation of each ONFT technique is explained and each technique's major advantages and disadvantages are pointed out. Emphasis is given to negative-pressure air-purifying respirators, as they are in most frequent use today. The requirements and recommendations for fit testing positive-pressure respirators are discussed as well. Finally, the presently available QNFT standards and regulations are summarized to assist the user in making fit testing decisions.

  • PDF

The Main Contents, Comment and Future Task for the Space Laws in Korea

  • Kim, Doo-Hwan
    • 한국항공우주법학회:학술대회논문집
    • /
    • 2008.05a
    • /
    • pp.273-294
    • /
    • 2008
  • Korea now has a rapidly expanding space programme with exploration aspirations. The government is giving priority to the aerospace industry and, to put it on a better footing, enacted an Aerospace Industry Development Promotion Act in 1987, a Space Development Promotion Act in 2005 and a New Space Compensation for Damage Act in 2007. I would like to describe briefly the legislative history, main contents and comment for these three space acts including especially launch licensing, registration of space objects, use of satellite information, astronaut rescue, liability for compensation, third party liability insurance and establishment of committee and plans to assist the Korean space effort. Furthermore author proposed to legislate a draft for the establishment of a new Korean National Space Development Agency (KNSDA: tentative title) to create a similar body to Japan Aerospace Exploration Agency (JAXA), British National Space Centre (BNSC) of UK, French Centre National d'Etudes Spatiales (CNES), German Aerospace Center (DLR), Swedish Space Corporation, China Aerospace Science and Industry Corporation, Indian Space Research Organization (ISRO) as well as the Korean Space Agency (KSA: Tentative title) to create a similar body to Canadian Space Agency, European Space Agency, Russian Space Agency, Italian Space Agency, Israel Space Agency, Indian Department of Space, National Aeronautics and Space Administration (NASA) of USA, China National Space Administration in order to develope efficiently space industry. A call is made for Asian countries to unite and further their space development through a regional space agency.

  • PDF

Characteristics of the Muscular Activities on the Feedback Control of Elbow Orthosis Using Pneumatic Rubber Artificial Muscle (공압 고무 인공근육을 장착한 주관절 보조기 피드백 제어 시 근력 특성)

  • Hong, Kyung-Ju;Kim, Kyung;Kwon, Tae-Kyu;Kim, Dong-Wook;Kim, Nam-Gyun
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.4
    • /
    • pp.725-728
    • /
    • 2008
  • An elbow orthosis with a pneumatic rubber actuator has been developed to assist and enhance upper limbs movements and has been examined for the effectiveness. The effectiveness of the elbow orthosis was examined by comparing muscular activities during alternate dumbbell curl motion wearing and not wearing the orthosis. The subjects participated in the experiment were younger adults in their twenties. The subjects were instructed to perform dumbbell curl motion in a sitting position wearing and not wearing orthosis in turn and a dynamometer was used to measure elbow joint torque outputs in an isokinetic mode. Orthosis was controlled using contractile muscle force that is measured from force sensor through cDAQ-9172 board. The air pressure of the pneumatic actuator was 0.3MPa the most suitable air pressure. For the analysis of muscular activities, Electromyography of the subjects was measured during alternate dumbbell curl motion. The experiment results showed that the muscular activities wearing the elbow orthosis were reduced. With this, we confirmed the effectiveness of the developed elbow orthosis.

Epidural Space Identification Device Using Air-filled Catheter (공기도관을 사용하는 경막외강 자동탐지기구)

  • 강재환;김현식;김경아;김상태;배진호;임승운;차은종
    • Journal of Biomedical Engineering Research
    • /
    • v.24 no.1
    • /
    • pp.9-13
    • /
    • 2003
  • An assist device was developed to identify the epidural space by continously monitoring the air-filled catheter pressure. The pressure signal appropriately amplified and filtered enabled to alarm the needle introduction into the epidural space by thresholding detection. Ten LEDs provided a visual change of catheter pressure before alarming for user convenience. Clinical trials were performed in 30 patients with 83% success rate at the first trial. When failed, the second trial was enough for successful anesthesia. The air volume introduced during each anesthesia was less than 1ml, causing side effects. Air filling of the catheter could also minimize infection possibility. Therefore, the present device guarantees safe anesthesia with user convenience.

An Off-line Maximum Torque Control Strategy of Wound Rotor Synchronous Machine with Nonlinear Parameters

  • Wang, Qi;Lee, Heon-Hyeong;Park, Hong-Joo;Kim, Sung-Il;Lee, Geun-Ho
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.3
    • /
    • pp.609-617
    • /
    • 2016
  • Belt-driven Starter Generator (BSG) differs from other mild hybrid systems as the crankshaft of vehicle are not run off. Motor permits a low-cost method of adding mild hybrid capabilities such as start-stop, power assist, and mild levels of regenerative braking. Wound rotor synchronous motor (WRSM) could be adopted in BSG system for HEV e-Assisted application instead of the interior permanent magnet synchronous motor (IPMSM). In practice, adequate torque is indispensable for starter assist system, and energy conversion should be taken into account for the HEV or EV as well. Particularly, flux weakening control is possible to realize by adjusting both direct axis components of current and field current in WRSM. Accordingly, this paper present an off-line current acquisition algorithm that can reasonably combine the stator and field current to acquire the maximum torque, meanwhile the energy conversion is taken into consideration by losses. Besides, on account of inductance influence by non-uniform air gap around rotor, nonlinear inductances and armature flux linkage against current variation are proposed to guarantee the results closer to reality. A computer-aided method for proposed algorithm are present and results are given in form of the Look-up table (LUT). The experiment shows the validity of algorithm.

The characters of lichens attached to the stonework cultural assets and removing methods of them (석조문화재에 부착하는 지의류의 특성과 그 제거방법)

  • Moon Kwang-Hee
    • 한국문화재보존과학회:학술대회논문집
    • /
    • 2005.11a
    • /
    • pp.100-103
    • /
    • 2005
  • Lichens play an important role in breaking down rocks physically and chemically. Physical weathering occurs mechanically through hyphae and rhizines growing into the rocks. Lichen substances such as oxalic acid, acidic polysaccharides and depsides may assist altering rocks chemically. These actions partly contribute to soil formation but prove harmful for the substratum. Some people do not like to keep lichens on stained glassof churches or on gravestones mainly because of its unglamorous appearance. A biocide, 'Koretrel', is very effective in removing lichens and blue-green algae from the surface of concrete. After spraying 'Koretrel' in the open air, lichens (Caloplaca sp., Endocarpon petrolepideum, Physciella melanchra, Phaeophyscia hispidula, etc.) growing on buildings died within three months and peeled off fromthe substratum. One year after treatment, concrete surfaces were almost lichen free for three or four years. The biocide makesuse of a kind of lichen substance and harmless both for substances and environment. Our recent experiments show that it is also useful for water grasses growing on the surface of an aqueduct of a hydroelectric power station.

  • PDF

A Study on the Improvements of Idle Performance for a SI Engine with a Syngas Assist (합성가스를 이용한 SI엔진의 아이들 성능 개선에 관한 연구)

  • Kim, Chang-Gi;Song, Chun-Sub;Cho, Young-Seok;Kang, Kern-Young
    • Journal of the Korean Society of Combustion
    • /
    • v.11 no.4
    • /
    • pp.14-21
    • /
    • 2006
  • In this study, syngas which is reformed from fossil fuel and has hydrogen as a major component, was added to a gasoline engine to improve combustion stability and exhaust emissions of idle state. Syngas fraction of the total supplied fuel varied to 0 %, 25 %, 50 % with various ignition timing and excess air ratio. Combustion stability, exhaust emissions, fuel consumption and exhaust gas temperature were measured to investigate the effects of syngas addition on idle performance. Results showed that syngas has ability to widely extend lean operation limit and ignition retard range with dramatical reduction of engine out emissions. It is supposed that the usage of syngas in the internal combustion engine is an effective solution to meet the future strict emission regulations.

  • PDF

A Study on Conflict Detection and Resolution for Aircraft Separation Assurance in a Free Flight Environment (자유비행 환경에서의 항공기 분리보장을 위한 충돌 탐지 및 해결 방법에 대한 고찰)

  • Kim, Chang-Hwan;Kang, Ja-Young
    • Journal of the Korean Society for Aviation and Aeronautics
    • /
    • v.18 no.3
    • /
    • pp.27-33
    • /
    • 2010
  • The goal for the CD&R system is to predict that a conflict is going to occur in the future, communicate the detected conflict to a human operator, and, in some cases, assist in the resolution of the conflict situation. To provide insight into different methods of conflict detection and resolution, a literature review of previous research models and current developmental and operational systems was performed. This paper focuses only on the specific attributes of each model, not on the depth to which a model has been analyzed, validated, or accepted. Thus, care should be taken to remember that a model that seems to be simple according to our categorization scheme may be significantly more viable than an apparently sophisticated model.

A Study of UWB Placement Optimization Based on Genetic Algorithm

  • Jung, Doyeon;Kim, Euiho
    • Journal of Positioning, Navigation, and Timing
    • /
    • v.11 no.2
    • /
    • pp.99-107
    • /
    • 2022
  • Urban Air Mobility (UAM) such as a drone taxi is one of the future transportations that have recently been attracting attention. Along with the construction of an urban terminal, an accurate landing system for UAM is also essential. However, in urban environments, reliable Global Navigation Satellite Systems (GNSS) signals cannot be received due to obstacles such as high-rise buildings which causes multipath and non-line of sight signal. Thus, the positioning result in urban environments from the GNSS signal is unreliable. Consequently, we propose the Ultra-Wideband (UWB) network to assist the soft landing of UAM on a vertiport. Since the positioning performance of UWB network depends on the layout of UWB anchors, it is necessary to optimize the layout of UWB anchors. In this paper, we propose a two-steps genetic algorithm that consists of binary genetic algorithm involved multi objectives fitness function and integer genetic algorithm involved robust solution searching fitness function in order to optimize taking into account Fresnel hole effects.

Design of Roll-over Protection Structure for an Orchard Sprayer (과수용 방제기 전도 방지 구조물의 설계)

  • Kang, Tae-Gyoung;Lee, Chai-Sik;Jun, Hyeon-Jong;Choi, Duck-Kyu;Park, Suk-Ho;Kim, Hyeok-Ju;Kang, Tae-Hwan
    • Journal of Biosystems Engineering
    • /
    • v.36 no.6
    • /
    • pp.407-415
    • /
    • 2011
  • Damage to agricultural production caused by insects and diseases affects farming yields. The orchard sprayer is mainly used in the country to protect the fruit in a large area, with less effort and at minimum cost. The excellent performance of the air blast spray increases the fruit protection. Chemical application in orchards has been accomplished by the orchard sprayers with air assist nozzles and a axial fan in Korea. However, the orchard sprayers without ROPS resulted in severe injury or death when operators drive the sprayers improperly on hilly orchard or farming road. This study was to develop a ROPS for the orchard sprayers improving farmer's safety. In this study, the accident case was used in analysing the design and building TOP structure of the orchard sprayer. The maximum impact, body torsion frame structures including the driver's protection are also analysed for adherence to safety regulations. The ROPS safety regulations according to the strength test results were established.