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모양우,유영태,위광한 조선대학교 동력자원연구소 1994 動力資源硏究所誌 Vol.16 No.2
A new instantaneous flowmeter for water hydraulic by means of cylindrical chokes is developed. In this method the instantaneous flowrate through chokes is predicted in real time from measurement of pressure difference on both sides of cylindrical choke. The experimental study for the flowrate of pulsating flow in a pipe is carried out to measure differential pressure drop by using a strain gauge pressure transducer with data acquisition and processing system. A pulsating flow is verified by visualization method. In the present study, the flow charcteristic variables of laminar pulsating flow are investigated analytically and experimentally in a circular pipe. Characteristics parameters of ratio of inertia term and pressure term(Φ_t.1) and ratio of viscous term and pressure term (Φ_z.1) are introduced to describe the flow pattern of laminar pulsating flow.
원형관로내 층류 맥동유동의 속도와 압력 분포에 관한 연구
박길문,유영태,위광환,이충주,정지철 조선대학교 생산기술연구소 1996 生産技術硏究 Vol.18 No.2
In this study basic equations for the pulsatile laminar flow in a circular rigid pipe containing a slightly compressible fluid are derived and analytical solutions for the distributions of wave propagation factor K, cross-sectional mean velocity u_(m) and pressure P are schematically developed and confirmed experimentally. The pulsatile flow with 0 ≤ f ≤ 48Hz and 0 ≤ Re ≤ 2500 generated by summing the oscillatory flow made by ball valve into steady one. The wave form of pulsatile flow is described as a longitudinal wave and particle velocities measured experimentally are group velocities of the wave packet which are always smaller than phase velocities which are approximate to the sonic velocity C when the radial dispersion and wall friction are negligible. Therefore wave number is approximated to k = ω/c for high angular velocity region. The axial pressures and centerline velocities were measured by strain-gage type pressure transducers and Pito-static tubes, respectively. The cross-sectional mean velocities calculated from centerline velocities with the parabolic distributions of the laminar flow and confirmed by using the ultrasonic flowmeter. We knew that axial distributions of oscillatory velocity and pressure coincide with thoeretical and depend on the Reynolds number and angular velocity.
Synthesis of the Molybdenum Precursor for Slurry-Phase Hydrocracking of Heavy Oil
Choi, Byong-Min,Son, Seok-Hwan,Noh, Min-Sub,Lee, Kwang-Seok,Lee, Chul-Wee,Park, Sun-Yeong,Chung, Min-Chul American Scientific Publishers 2018 Journal of Nanoscience and Nanotechnology Vol.18 No.2
<P>In this study, Molybdenum precursors were synthesized with butanoic acid, hexanoic acid, nonanoic acid, decanoic acid, and undecanoic acid. In order to determine chemical structure of Synthesized molybdenum precursors, H-1(C-13)-NMR, EA and ICP were used pyrolysis properties were measured TGA. The molybdenum precursors was used for Hydrocracking of Vacuum R(1)esidue (VR). It was shown that molybdenum nonanoate(3) was shown the lowerst Toluene Insoluble and Gas Product about 2.1 and 5.0 percent.</P>
강바닥판 교량에 적용된 에폭시 아스팔트 포장의 응력 해석 연구
조신행,김낙석,위광환,정윤수,Jo. Shin Heang,Kim. Nakseok,Wee. Kwang Hwan,Jung. Yoon Soo 한국방재학회 2013 한국방재학회논문집 Vol.13 No.6
에폭시 아스팔트는 장경간 강바닥판 교량의 교면포장 재료로 사용하기에 매우 적합하다. 에폭시 아스팔트의 뛰어난 성능은 5.0-5.5 cm의 두께로 포장이 가능하여 교량의 고정하중을 감소시킬 수 있는 경제적이며 효율적인 교면포장 재료이다. 그러나 국내 적용사례가 부족하며 얇아진 포장 두께에 따른 응력 전달 경로의 변화로 교량 부재의 손상 및 파손에 대한 우려가 있다. 본 연구에서는 에폭시 아스팔트 포장이 적용된 강바닥판 교량의 구조해석을 수행하고 실내 실험 결과와 비교하여 적용성을 평가하고자 하였다. 연구 결과, 유한요소해석에서 포장에 발생하는 인장응력은 간접인장강도에 비해 매우 작았으며, 부착면에서의 전단응력도 접착강도에 비해 작은 것으로 나타났다. 따라서 에폭시 아스팔트 포장은 강바닥판 교량의 박층 포장으로서 충분한 안정성과 내구성능을 제공할 수 있는 것으로 나타났다. Epoxy asphalt is an excellent material for overlay of long-span bridges with orthotropic steel deck. The superior characteristics of epoxy asphalt allow epoxy asphalt overlay to be applied with a thickness of 5.0-5.5 cm, which can significantly reduce dead load and benefit the structural efficiency. With limited experience in the domestic market however, concerns still exists regarding higher risk of steel deck damage due to the thinner application of the overlay. In this study, structural analysis of an orthotropic steel deck with epoxy asphalt overlay is carried out to evaluate a field application example. Analysis results showed that deformation and tensile stress were very small, and shear stress between layers was smaller than bond strength. According to the analysis of study results, the epoxy asphalt pavement can provide sufficient stability and performance life as thin-overlay on orthotropic steel bridge deck.