• 제목/요약/키워드: TEST BED

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모달시험기법을 이용한 침목플로팅궤도의 고유진동수 분석 (Natural Frequency Analysis of Sleeper Floating Track System using Modal Test Technique)

  • 최정열
    • 문화기술의 융합
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    • 제10권3호
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    • pp.833-838
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    • 2024
  • 도시철도 침목플로팅궤도(STEDEF)는 침목상자와 침목방진패드를 이용하여 침목과 콘크리트 도상을 구조적으로 분리하여 콘크리트 도상에 전달되는 진동을 감소시키는 구조이다. 최근에는 20년 이상 공용중인 침목플로팅궤도의 침목방진패드 열화가 발생하고 있다. 이에 침목방진패드에 대한 성능을 평가하기 위해 침목방진패드 발췌 후 정적 스프링강성 시험을 수행하고 있다. 해당 평가기법은 사용 중인 침목방진패드를 반드시 교체한 후 평가를 수행한다. 그러나 궤도 고유진동수는 침목방진패드 스프링강성 및 콘크리트 도상의 융기와 침하에 따라 변화할 수 있다. 본 연구에서는 궤도 고유진동수를 평가하기 위해 모달시험기법을 사용하였다. 이를 위해 실험실 규모에서 침목상자 소재, 침목방진패드 스프링강성 및 콘크리트 도상 융기 및 침하에 따른 궤도 고유진동수를 모달시험을 이용하여 측정하였다. 침목플로팅궤도 고유진동수는 침목방진패드 스프링강성 변화에 따라 직접적인 영향을 받는 것으로 분석되었다. 또한 콘크리트 도상의 융기 및 침하에 따른 고유진동수 변화도 큰 것으로 나타났다. 따라서 본 연구에서 제시한 모달시험기법을 이용하여 침목방진패드의 열화 및 뜬 침목 평가 등에 활용할 수 있을 것으로 판단된다.

심폐소생술 제공자의 발판 높이와 자세가 기본심폐소생술의 정확도에 미치는 영향 (The Impact on the accuracy of the basic CPR according to position and foot-board height of the basic CPR provider)

  • 최은숙;조근자
    • 한국응급구조학회지
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    • 제12권3호
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    • pp.27-41
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    • 2008
  • Purpose : The purpose of this study was to supply basic data for the impact on the accuracy of basic CPR according to position and foot-board height of basic CPR provider. Methods : Study design was within - group design. Subjects were 25 EMT-P Students in K city. Interventions was basic CPR performed on a resuscitation manikin placed on a hospital bed, kneeling on the bed adjacent to the manikin. Data was analyzed using descriptive statistics and Friedman test. Results : In case of the basic CPR performed on a resuscitation manikin placed on a hospital bed, ventilation accuracy was the highest in less than 160 cm height, foot-board height : $34.2{\pm}1.48cm$, 91.4% and in 161-165 cm height, foot-board height : $26.0{\pm}2.14cm$, 88.4% and in 171-175 cm height, foot-board height : $23.0{\pm}1.41cm$, 91.3% and in the above 176 cm, kneeling on the bed, 95%. Chest compression accuracy was the highest in less than 160 cm height, foot-board height : $30.2{\pm}1.48cm$, 95.6% and in 161-165 cm height, kneeling on the bed, 97.6% and in 171-175 cm height, kneeling on the bed, 98.5% and in the above 176 cm, kneeling on the bed, 98.7% and foot-board height : $20.5{\pm}1.91cm$, 98.7%. Chest compression error was due to too weak : 2.0-35.4 times. There were ststistically significant differences in 191-195 cm group according to chest compression mean depths($x^2=10.824$, p = .013) and chest compression error (p = .040). Conclusion : In contrast to current guidelines, the position and foot-board height of basic CPR provider are very important to the accuracy of the basic CPR. Furthermore, we recommend that a using real time audiovisual feedaback system significantly improve the quality of chest compression and ventilation during resuscitation.

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가압 유동층 반응기에서 SEWGS 공정을 위한 WGS 촉매의 반응특성 (Reaction Characteristics of WGS Catalyst for SEWGS Process in a Pressurized Fluidized Bed Reactor)

  • 김하나;이동호;이승용;황택성;류호정
    • 한국수소및신에너지학회논문집
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    • 제23권4호
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    • pp.337-345
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    • 2012
  • To check effects of operating variables on reaction characteristics of WGS catalyst for SEWGS process, water gas shift reaction tests were carried out in a pressurized fluidized bed reactor using commercial WGS catalyst and sand(as a substitute for $CO_2$ absorbent) as bed materials. Simulated syngas(mixed with $N_2$) was used as a reactant gas. Operating temperature was $210^{\circ}C$ and operating pressure was 20 bar. WGS catalyst content, steam/CO ratio, gas velocity, and syngas concentration were considered as experimental variables. CO conversion increased as the catalyst content and steam/CO ratio increased. CO conversion at fluidized bed condition was higher than that of fixed bed condition. However, CO conversion were maintained almost same value within the fluidized bed condition. CO conversion decreased as the syngas concentration increased. The optimum operation condition was confirmed and long time water gas shift reaction test up to 24 hours at the optimum operating conditions was carried out.