• Title/Summary/Keyword: face pressure

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Cooling Performance Enhancement of a Rocket Engine Injector Face Plate (로켓엔진 분사면의 냉각성능 향상)

  • Cho Won Kook;Seol Woo Seok
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.3
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    • pp.92-100
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    • 2005
  • An optimal fuel manifold is suggested to improve the cooling performance of an injector face plate. The cooling performance at the center area of the injector face plate is to be augmented while the spatial injection uniformity is maintained. The comparison of the cooling performance of f candidates gives the conclusion that the dividing plate from 2-3 injector .ow to 9-10 injector. row is an optimal. The maximum face plate temperature decreases by 27$\%$ while the injection uniformity is close to that of the original design. The pressure drop in the fuel manifold of the optimal design is also same as the original design.

Literature Study for Categorizing Physical Properties of Face, Pulse, Skin and Voice Based on Health State of Sasang Constitutions (사상체질별 건강수준에 따른 맥상, 안면, 피부, 음성의 물리량 도출을 위한 문헌고찰연구)

  • Lee, Jae-Chul;Lee, Yu-Jeong;Kim, Ja-Euk;Kim, Sang-Kil;Kang, Nam-Sik;Kim, Jong-Yeol;Kim, Sang-Hyuk
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.25 no.4
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    • pp.755-758
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    • 2011
  • Sasang Constitutional Medicine (SCM) suggests the concept of health condition which is owned of different properties by each Sasang Constitution. But SCM theory has concentrate to explaining different symptoms that distinguish health condition, not much concerned with practical methods like face features, pulse diagnosis, skin surface properties and voice features. Physical properties of practical diagnosis methods from literature finding have been researched. As a result, complexion and face moisture were described to be physical properties related to health State. In scope of pulse diagnosis, depth, rate, contour, width and pressure are related. Skin surfaces' elasticity, moisture, fraction properties were also suggested as factors of health State of Sasang Constitution. We assume that this study would contribute further studies for objectifying and quantifying diagnosis methods to evaluate health state grades of Sasang Constitution.

Prediction of the Propeller Face Cavity Inception and Experimental Verification (프로펠러 압력면 캐비테이션의 초기발생 추정 및 실험 검증)

  • Ahn, Byoung-Kwon;Lee, Chang-Sup;Yu, Yong-Wan;Moon, Il-Sung
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.5
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    • pp.467-473
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    • 2007
  • Cavitation phenomena appearing on ship propellers have long been interested and recent theoretical analysises give good results comparing with model tests. In accordance with a continuous rise in heavy powered and high speed ships, hull forms have been changed and loads acting on the propeller surface have also been increased, and they result in various and particular cavitations. In some cases, cavitation appears not only on the back but also on the face of the propeller and it causes additive pressure fluctuations and erosion of the propeller and reduces propulsion efficiency of the ship. In this study, we predict the face cavity inception using unsteady propeller analysis based on the panel method and compare the results with experimental observations.

The Study on the Simple Measurement by Using the Strain Gauge at Dam Dynamic Behavior Analysis (댐 거동 분석에서의 Strain Gauge를 이용한 단일 계측에 관한 연구)

  • Lee, Seungho
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.1
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    • pp.5-11
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    • 2007
  • Internal stress variation in the face slab concrete induced by reservoir water pressure may affect on the stability of the dam so that the reclamation type of strain gauge is applied for measuring internal stress variation. In this study, internal as well as external stress variation of dam was measured by using strain gauge that was reclaimed to the ${\circ}{\circ}$ dam. In the result, it was confirmed that other measurements by relevant gauges need to be supplemented as the use of strain gauge only is insufficient to evaluate the stability analysis and global behavior of the dam.

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Predicting ground condition ahead of tunnel face utilizing electrical resistivity applicable to shield TBM (Shield TBM에 적용 가능한 전기비저항 기반 터널 굴착면 전방 예측기술)

  • Park, Jin-Ho;Lee, Kang-Hyun;Shin, Young-Jin;Kim, Jae-Young;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.6
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    • pp.599-614
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    • 2014
  • When tunnelling with TBM (Tunnel Boring Machine), accessibility to tunnel face is very limited because tunnel face is mostly occupied by a bunch of machines. Existing techniques that can predict ground condition ahead of TBM tunnel are extremely limited. In this study, the TBM Resistivity Prediction (TRP) system has been developed for predicting anomalous zone ahead of tunnel face utilizing electrical resistivity. The applicability and prediction accuracy of the developed system has been verified by performing field tests at subway tunnel construction site in which an EPB (Earth Pressure Balanced) shield TBM was used for tunnelling work. The TRP system is able to predicts the location, thickness and electrical properties of anomalous zone by performing inverse analysis using measured resistivity of the ground. To make field tests possible, an apparatus was devised to attach electrode to tunnel face through the chamber. The electrode can be advanced from the chamber to the tunnel face to fully touch the ground in front of the tunnel face. In the 1st field test, none of the anomalous zone was predicted, because the rock around the tunnel face has the same resistivity and permittivity with the rock ahead of tunnel face. In the 2nd field test, 5 m thick anomalous zone was predicted with lower permittivity than that of the rock around the tunnel face. The test results match well with the ground condition predicted, respectively, from geophysical exploration, or directly obtained either from drilling boreholes or from daily observed muck condition.

Performance Evaluation of Gas Cleaning Industrial Filters using a Bi-Modal Test Aerosol for Dust Loading Studies

  • Lee, Jae-Keun;Kim, Seong-Chan;Benjamin Y.H. Liu
    • Journal of Energy Engineering
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    • v.5 no.2
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    • pp.131-137
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    • 1996
  • Typical size distribution of emission particulates is bi-modal in shape with particles in the fine mode (< 2.0 $\mu\textrm{m}$) and the coarse mode. An experimental study of pressure drop across the industrial gas cleaning filters has been conducted using particle mixture of fine alumina and coarse Arizona dusts with a rotating aerosol disperser to generate the bi-modal test aerosol. Pressure drop increased linearly with increasing mass loading. The pressure drop was found to be strongly dependent upon the mass ratio of fine to coarse particles. The smaller the mass ratio of fine to coarse particles and the higher face velocity are, the faster pressure drop rises. The fine particles and the greater inertia of the particle moving fast would cause a denser cake formation on the filter surface, resulting in a greater specific resistance to the gas flow.

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Numerical Analysis on the Die Pad/Epoxy Molding Compound(EMC) Interface Delamination in Plastic Packages under Thermal and Vapor Pressure Loadings

  • Jin Yu
    • Journal of the Microelectronics and Packaging Society
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    • v.5 no.2
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    • pp.37-48
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    • 1998
  • The popcorn cracking phenomena in plastic IC packages during reflow soldering are investigated by considering the heat transfer and moisture diffusion through the epoxy molding compound(EMC) along with the mechanics of interface delamination. Heat transfer and moisture diffusion through EMC under die pad are analyzed by finite difference method (FDM)during the pre-conditioning and subsequent reflow soldiering pro-cess and the amounts of moisture mass and vapor pressure at delaminated die pad/ EMC interface are calculated as a function of the reflow soldering time. The energy release rate stress intensity factor and phase angle were obtained under various loading conditions which are thermal crack face vapor pressure and mixed loadings. It was shown that thermal loading was the main driving force for the crack propagation for small crack lengths but vapor pressure loading played more significant role as crack grew.

Particle Laden Flows Around Orifice Plates for Pressure Control in Pulverized Coal Pipe Lines (분체 이송관내 압력 조절을 위한 오리피스 주위에서의 입자 유동 및 마모 해석)

  • Cho, Hyung-Hee;Lee, Jae-Keun;Park, Ho-Dong;Seo, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.11
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    • pp.1499-1508
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    • 1998
  • A numerical study is performed to investigate pressure drops, particle trajectories and erosion around orifice plates in pulverized coal pipe lines. Particle impaction rates change significantly with orifice shapes and Stokes numbers. At Reynolds number of $5{\times}10^5$, the pulverized coal flows well with streamlines and do not collide at the orifice plates at small sizes (${\sim}20{\mu}m$). However, the large particles (over $70{\mu}m$) impact on the front face of the orifice and erode the orifice surface. The pressure loss coefficients around the erode orifice are largely different from the designed original orifice.

Experimental study on the longitudinal load transfer of a shallow tunnel depending on the deformation tunnel face (II) (얕은 터널의 굴진면 변형에 따른 종방향 하중전이 특성에 대한 실험적 연구(II))

  • Kim, Yang Woon;Lee, Sang Duk
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.5
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    • pp.499-509
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    • 2016
  • In recent years, the use of underground spaces becomes more frequent and the demands for urban tunnels are rapidly increasing. The urban tunnels constructed in the ground with a shallow and soft cover might be deformed in various forms on the face, which would lead, the tunnels to behavior 3-dimensionally, which may have a great impact on the longitudinal load transfer. The tunnel face might deform in various forms depending on the construction method, overburden and the heterogeneity of the ground. And accordingly, the type and size of the distribution of the load transferred to the ground adjacent to the tunnel face as well as the form of the loosened ground may appear in various ways depending on the deformation form of the tunnel face. Therefore, in this study was conducted model tests by idealizing the deformation behavior of the tunnel face, that were constant deformation, the maximum deformation on the top and the maximum deformation on the bottom. And the test results were analyzed focusing on the deformation of the face and the longitudinal load transfer at the ground above the tunnel. As results, it turned out that the size and the distribution type of the load, which was transferred to the tunnel as well as the earth pressure on the face were affected by the deformation type of the face. The largest load was transferred to the tunnel when the deformation was in a constant form. Less load was transferred when the maximum deformation on the bottom, and the least load was transferred when the maximum deformation on the top. In addition, it turned out that, if the cover became more shallow, a longitudinal load transfer in the tunnel would limited to the region close to the face; however, if the cover became higher than a certain value, the area of the load transfer would become wider.

Competitive Pressure and Business Performance in East Java Batik Industry

  • SOEWARNO, Noorlailie;TJAHJADI, Bambang;PERMATANADIA, Devitania
    • The Journal of Asian Finance, Economics and Business
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    • v.7 no.12
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    • pp.329-336
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    • 2020
  • This study aims to assess the impact of competitive pressure and innovation capability on business performance in small- and medium-sized enterprises (SMEs) in the batik industry in East Java, Indonesia. Furthermore, this study explores the impact of competitive pressure on business performance through innovation capability as a mediating variable. This research was quantitative using primary data with questionnaire as a method of sampling collection. The measurement of the variables was captured using Likert scale. The respondents were small- and medium-sized enterprises (SMEs) in the batik industry in East Java Province, Indonesia. The sample totaled 254 subjects. The data analysis was done using SEM-PLS. The results of the study show that: 1) there was a positive direct impact of competitive pressure on business performance; 2) competition pressure positively influences innovation capability; 3) innovation capability positively influences business performance; and 4) innovation capability has a partial mediating role in the effect of competitive pressures on business performance. The findings of this study suggest that managers in SME's batik industry should increase their effort to cope with the high competitive pressure to increase the innovation capability, so that they can have an advantage to face successfully competitors, leading to higher business performance.