• 제목/요약/키워드: Technology Asymmetry

검색결과 270건 처리시간 0.071초

개도율에 따른 가스파이프라인용 볼 밸브 후류유동의 수치평가 (Numerical Evaluation of Flow Nature at the Downstream of a Ball Valve Used for Gas Pipelines with Valve Opening Rates)

  • 김철규;이상문;장춘만
    • 한국수소및신에너지학회논문집
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    • 제29권4호
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    • pp.370-377
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    • 2018
  • Ball valve has been widely used in the field of high-pressure gas pipeline as an important component because of its low flow resistance and good leakage performance. The present paper focuses on the flow nature at the downstream of the ball valve used for gas pipelines according to valve opening rates. Steady 3-D RANS equations, SC/Tetra, have been introduced to analyze the flow characteristics inside the ball valve. Numerical boundary conditions at the inlet and outlet of the valve system are imposed by mass flow-rate and pressure, respectively. Velocity distributions obtained by numerical simulation are compared with respect to the valve opening rates of 30, 50, and 70%. Cavity distributions, asymmetry flow velocity and the flow stabilization point at each opening rate are also compared. When the valve opening rates are 30 and 50%, the flow stabilization requires the sufficient length of 10D or more due to the influence of the recirculation flow at the downstream of the valve.

Effects of modelling on the earthquake response of asymmetrical multistory buildings

  • Thambiratnam, David P.
    • Structural Engineering and Mechanics
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    • 제2권2호
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    • pp.211-225
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    • 1994
  • Responses of asymmetrical multistorey buildings to earthquakes are obtained by quasi-static code approach and real time dynamic analysis, using two different structural models. In the first model, all vertical members are assumed to be restrained at the slab levels and hence their end rotations, about horizontal axes, are taken as zero. In the second model this restriction is removed and the rotation is assumed to be proportional to the lateral stiffness of the member. A simple microcomputer based procedure is used in the analyses, by both models. Numerical examples are presented where results obtained from both the models are given. Effects of modelling on the response of three buildings, each with a different type and degree of asymmetry, are studied. Results for deflections and shear forces are presented and the effects of the type of model on the response are discussed.

TRIP강의 비대칭 거동과 스프링백 (Asymmetric Behavior and Springback of Transformation-Induced Plasticity (TRIP) Steels)

  • 전성욱;정재봉;이현석;김병민;김지훈
    • 소성∙가공
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    • 제26권6호
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    • pp.333-340
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    • 2017
  • The cyclic hardening behavior of transformation-induced plasticity (TRIP) steels shows tension-compression asymmetry known to be attributed to transformation of retained austenite into martensite during deformation. In this work, YoshidaUemori hardening model was used to represent the asymmetric hardening behavior of TRIP1180 steel. Yoshida-Uemori hardening model parameters were obtained from three sets of data: tension-compression, compression-tension, and a combination of the two. Material models were validated for U-bending and springback.

마그네슘 합금 구성식을 이용한 스프링백 예측 (Prediction of Springback by Using Constitutive Equations of Mg Alloy Sheets)

  • 이명규;정관수;김성준;김헌영
    • 소성∙가공
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    • 제17권2호
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    • pp.97-101
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    • 2008
  • Unique constitutive behavior of magnesium alloys as one of hexagonal close packed(hcp) metals has been implemented into the commercial finite element program ABAQUS. The constitutive equations can represent asymmetry in tension-compression yield stresses and flow curves. For the verification purpose, the springback of AZ31B magnesium alloy sheet was measured using the unconstrained cylindrical bending test proposed in Numisheet'2002 benchmark committee. Besides the developed constitutive models, the isotropic models based on tensile and compressive properties were also considered for comparison purpose. The predicted results by the finite element analysis and corresponding experiments showed enhanced prediction capability in springback analysis.

Managing Information Asymmetry Risks Using Deal Syndication and Domain Specialization: An Indian Context

  • Joshi, Kshitija
    • Asian Journal of Innovation and Policy
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    • 제7권1호
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    • pp.150-177
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    • 2018
  • We review two specific risk management strategies of venture capitalists (VCs): deal syndication and domain specialization with respect to their explicit role in adjudging and managing the overall magnitude of information asymmetry risks. These are analyzed for three distinct categories of VC firms as classified by their funding stage focus (early vs. late), ownership type (foreign vs. domestic) and the human capital composition of the core VC team (entrepreneurial vs. investor). The analysis is based on both secondary data and primary data for active 72 VC firms in India. Syndication is moderately important for entrepreneurial VC firms, but not at all important for early-stage focused and foreign VC firms. This finding is distinctly different from what has been conventionally observed in the literature. Among the various arenas of domain specialization, high-technology focus is important for all segments of VC firms. In the context of investment-stage focus, foreign VC firms exhibit growth-stage specialization, while entrepreneurial VC firms concentrate on earlier investment stages.