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Structural Design of a Movable Bearing Shoe for Large Bridge Using Three Dimensional Finite Element Method (3차원 유한요소법을 이용한 장대교량용 가동받침 설계)

  • Cho, Jong-Rae;Lee, Boo-Youn
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.7
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    • pp.51-57
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    • 1999
  • Recently, long large bridges are built for mass transportation. Movable bearing shoes are important components of the bridges because they support movement of translation and rotation of bridge. In design stage of the long large bridges, detailed analyses using the finite element method are performed to guarantee safety and reliability. For that purpose, three-dimensional modeling is carried out by I-DEAS software and finite element analysis by ANSYS software. Results of the analyses are reviewed and important design factors for movable bearing shoes are discussed.

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A Study on the Creation of Slope Instability Map Using Geographic Information Systems. (GIS를 이용한 사면위험도 작성기법 연구)

  • 유명환
    • Economic and Environmental Geology
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    • v.33 no.2
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    • pp.129-138
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    • 2000
  • The various types of geohazards like landslides resulted from civil construction (i.e. highway construction) must of analysed considering all the possible influential factor systematically. Thus, by using GIS, slope stability can be evaluated, and it can be used as a data for further detailed investigation. So the aim of this study is to present a data for decision making in selecting suitable point for remediation. For analysing slope instability, through appropriate definition and classification, landslide mechanism must be understood. In building GIS model, the selection of appropriate factors and their rating system should be made. For this, the characteristics and the mechanism of landslide have to be understood. And suitable coverage should be chosen for the model considering the slope conditions. In this study, field investigation in lst and 2nd Section, Chung-ang highway was carried out. From the field data, GIS model on slope instability was created. 5 coverages were used for it. From the result of this study, 12 unstable sections were found out and more detailed investigation is needed there.

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Numerical Modeling for Vaporization, Auto-Ignition and Combustion Processes of Dimethyl Ether (DME) Fuel Sprays (DME 연료의 증발, 점화 및 분무연소특성 해석)

  • Yu, Yong-Wook;Lee, Jeong-Won;Kim, Yong-Mo
    • Journal of the Korean Society of Combustion
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    • v.12 no.3
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    • pp.33-39
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    • 2007
  • The present study is mainly motivated to investigate the vaporization, auto-ignition and combustion processes in high-pressure engine conditions. In order to realistically simulate the dimethyl ether (DME) spray dynamics and vaporization characteristics in high-pressure and high-temperature environment, the high-pressure vaporization model is utilized. The interaction between chemistry and turbulence is treated by employing the Representative Interaction Flamelet (RIF) model. The detailed chemistry of 336 elementary steps and 78 chemical species is used for the DME/air reaction. Numerical results indicate that the RIF approach, together with the high-pressure vaporization model, successfully predicts the essential feature of ignition and spray combustion processes.

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Improvement of Detailed Fault Point Decision Using EMTP Analysis of Search Coil Method for HVDC Cables (Search Coil법의 EMTP 분석을 통한 HVDC 케이블 상세 고장지점 판정 정확도 개선)

  • Jung, Chae-Kyun;Park, Jin-Woo;Yang, Byeong-Mo;Kang, Ji-Won;Lee, Jong-Beom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.9
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    • pp.1656-1662
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    • 2011
  • In a previous paper, the EMTP modeling technique using search coil test is established through various transient analysis including system grounding condition and grounding resistance for HVDC submarine cables. It was also proved by comparison with real test results. Based on this EMTP modeling technique, in this paper, it will be applied for modeling of ${\pm}180kV$ real HVDC submarine system(Jeju~Haenam). This paper variously analyses the effects of fault resistance including the resistance between core and sheath, the resistance between sheath and amore and the resistance between amore and sea water through EMTP modeling of search coil method. The results can contribute to the accuracy of detailed fault point prediction of search coil test for HVDC submarine cables.

Application Method Analysis at Voltage Drop Calculations on Low Voltage Feeder by IEC Standard (국제 표준에 따른 저압간선 전압강하 계산시 적용 방법 고찰)

  • Kim, Gi-Hyun;Lee, Ju-Chul;Choi, Young-Kyu;Kim, Han-Soo;Lee, Young-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.6
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    • pp.53-58
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    • 2012
  • A conductor has been produced according to IEC standard and low voltage electrical facility has been installed according to IEC 60364. But because of many related and varied standards, it is difficult to apply to design and inspect for electrical equipment. We researched the necessity of design guide which is detailed and systematization from survey. For detailed design guide, we suggest application method and review items at calculations for voltage drop calculations on low voltage feeder by IEC 60364, BS 7671 standard and Consumer's Electrical Installation Guide.

On modeling of fire resistance tests on concrete and reinforced-concrete structures

  • Ibrahimbegovic, Adnan;Boulkertous, Amor;Davenne, Luc;Muhasilovic, Medzid;Pokrklic, Ahmed
    • Computers and Concrete
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    • v.7 no.4
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    • pp.285-301
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    • 2010
  • In this work we first review the statistical data on large fires in urban areas, presenting a detailed list of causes of fires, the type of damage to concrete and reinforced concrete structures. We also present the modern experimental approach for studying the fire-resistance of different structural components, along with the role of numerical modeling to provide more detailed information on quantifying the temperature and heat flux fields. In the last part of this work we provide the refined models for assessment of fire-induced damage in structures built of concrete and/or reinforced-concrete. We show that the refined models of this kind are needed to provide a more thorough explanation of damage and to complete the damage assessment and post-fire evaluations.

Theoretical Interpretation of the UV Obervations of Elliptical Galaxies from NASA Space Mission

  • Lee, Young-Wook-
    • Bulletin of the Korean Space Science Society
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    • 1993.04a
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    • pp.15-15
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    • 1993
  • During the past two decades, ultraviolet(UV) observations of elliptical galaxies and spiral bulges from the OAO-2 and HE satellites have established that the upturn in the specturm below 2000A is a common feature of these early-type system Because of its important implications for the formation of galaxies, astuonemical literature is replete with nurmerous discussions about the origin of the UV flux yet the situation remains controversal. New light on the problem is shed by the recent observations Some the Astro-1 space shuttle mission which suggest that the metal-poor horizontal-branch(HB) stars merit more detailed consideration for the origin of the UV flux It is shown here that such stars in these systems can indeedexplain the UV flux It is suggested that ttle obserred correlation between the UVupturn and total mass is due to the Possibility that the more massive galaxies tend to form earlier than the less massive galaxies as a result of mere efficient star formation in denser environments. It remains a task of mere detailed population synthesis nudels, now in progress, to put these results on a firmer quantitative basis.

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An investigation of the wind statistics and extreme gust events at a rural site

  • Sterling, M.;Baker, C.J.;Richards, P.J.;Hoxey, R.P.;Quinn, A.D.
    • Wind and Structures
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    • v.9 no.3
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    • pp.193-215
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    • 2006
  • This paper presents an analysis of wind velocity measurements obtained from four ultrasonic anemometers arranged in a vertical formation. The anemometers were located in a rural environment with a view to providing detailed information on the flow statistics of the lower part of the atmospheric boundary layer, particularly for the extreme wind events that are important in loading calculations. The data is analysed using both conventional analysis and conditional sampling. The latter is combined with wavelet analysis in order to provide a detailed analysis of the energy/frequency relationship of the extreme events. The work presented in this paper suggests that on average the extreme events occur as a result of the superposition of two independent mechanisms - large scale events that scale on the atmospheric boundary layer thickness and small scale events a few tens of metres in size.

Flame Behaviors of Counterflow Nonpremixed Flame Perturbed by a Vortex (와동에 의해 교란된 대향류 비예혼합화염의 화염거동)

  • Oh, Chang-Bo;Lee, Chang-Eon
    • 한국연소학회:학술대회논문집
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    • 2004.06a
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    • pp.57-63
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    • 2004
  • A two-dimensional direct numerical simulation was performed to investigate the flame behaviors of $CH_4/N_2$-Air counterflow nonpremixed flame interacting with a single vortex. The detailed transport properties and a modified 16-step augmented reduced mechanism based on Miller and Bowman's detailed reaction mechanism are adopted in this calculation. The results showed that an initially flat stagnation plane, on which an axial velocity was zero, was deformed into a complex-shaped plane, and an initial stagnation point was moved far away from a vortex head when the counterflow field was perturbed by the vortex. It was noted that the movement of stagnation point could alter the species transport mechanism to the flame surface. It was also identified that the altered species transport mechanism affected the distributions of the mixture fraction and the scalar dissipation rate.

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A Study on the Systems Engineering Detailed Schedule for LRT Project (경량전철사업의 시스템엔지니어링활동을 위한 상세일정계획 작성방법 연구)

  • Han, Seok Youn;Kim, Joo Uk;Choi, Yo Chul;Kang, Do Hoon
    • Journal of the Korean Society of Systems Engineering
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    • v.8 no.2
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    • pp.11-17
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    • 2012
  • Suppliers in light rail transit project makes a systems engineering management plan(SEMP) as a top level plan which has a SEMS and SEDS as an control and monitoring means. In this paper, we analyze the international standards and some related documents, and present the directions to make the SEMS and SEDS which have WBS, accomplishments, schedule, events, person in charge. And then customize the project management tool and make SEMS and SEDS of LRT project as an example. The research results can be applied in LRT project after tailoring based on the project.