• Title/Summary/Keyword: Governing Body

검색결과 235건 처리시간 0.022초

전기 엎셋팅 가공시의 온도분포에 관한 연구 (A Study on the Temperature Distribution of Materials Due to Electric Upsetting Forming)

  • 왕지석;박태인
    • Journal of Advanced Marine Engineering and Technology
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    • 제18권3호
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    • pp.1-9
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    • 1994
  • The transient temperature distribution of materials during upsetting forming is very important for quality of upsetted workpiece and understanding the thermal characteristics of upsetting is essential for optimum control of the forming. In this paper it is shown that the governing equation of heat transfer for axi-symetric body can be derived from minimizing a functional, and from this theory, formulation of analysis by the finite element method is presented. It is also shown that the thermal contact resistance between two bodies can be represented by equivalent coefficient of heat conductivity. Some examples of calsulated transient temperature distributions by the computer program diveloped from the theory presented in this paper are given in graphic forms. It is proven that the results calculations are very plausible.

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비대선 모형에 대한 점성유동의 수치해석연구 (A Study on the Numerical Analysis of the Viscous Flow for a Full Ship Model)

  • 박명규;강국진
    • 한국항해학회지
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    • 제19권2호
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    • pp.13-22
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    • 1995
  • This paper presents the numerical analysis results of the viscous flow for a full ship model. The mass and momentum conservation equations are used for governing equations, and the flow field is discretized by the Finite-Volume Method for the numerical calculation. An algebraic grid and elliptic grid generation techniques are adopted for generation of the body-fitted coordinates system, which is suitable to ship's hull forms. Time-marching procedure is used to solve the three-dimensional unsteady problem, where the convection terms are approximated by the QUICK scheme and the 2nd-order central differencing scheme is used for other spatial derivatives. A Sub-Grid Scale turbulence model is used to approximate the turbulence, and the wall function is used at the body surface. Pressure and velocity fields are calculated by the simultaneous iteration method. Numerical calculations were accomplished for the Crude Oil Tanker(DWT 95,000tons, Cb=0.805) model. Calculation results are compared to the experimental results and show good agreements.

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체심입방격자 단결정의 소성스핀에 관한 연구 (A Study on the Plastic Spin of Body Centered Crystal)

  • 남용윤;김사수
    • 한국해양공학회지
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    • 제10권2호
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    • pp.53-60
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    • 1996
  • Many studies on the plastic spin have been done, but it is still an opened subject. It is essential for the modelling of plastic spin to understand its origin and governing parameters. For the task, it is helpful to know the hehavior of sigle crystal. This study gives the interpretations for the plastic spin of a B.C.C(body centered cubic crystal) by numerical simulation. It is discussed that the different levels of shear stresses induced on each slip pair in crystallographic slip systems and the nonlinear relationship between shear stress and slip velocity are the fundamental mechanisms of plastic spins. Finally some comments are provided on the plastic spin of polycrystal.

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다공성 핵연료 소결체의 유효열전도율의 수치적 해석 (A numerical analysis of effective thermal conductivity of a porous nuclear fuel)

  • 주영철;박권현
    • 대한기계학회논문집
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    • 제11권3호
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    • pp.368-375
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    • 1987
  • 본 연구에서는 이러한 기하형태의 불규칙성을 쉽게 고려할 수 있는 윤곽좌표계 (body fitted coordinate systems)를 이용하여 다공성 물질의 유효열전도율을 결정하 는 방법을 제시하였다.기공의 형상을 원형으로 가정하고 기공율과 기공 내부기체와 고체의 열전도율비 등의 변수가 유효열전도율과 이들 변수의 상관관계식을 제안하였으 며, 또한 핵연료 소결체와 같은 실제적인 다공성 물질의 유효열전도율을 해석하는데 좀 더 타당한 타원형 형상의 기공 가정방법을 제시하였다.

Hygro-thermal wave propagation in functionally graded double-layered nanotubes systems

  • She, Gui-Lin;Ren, Yi-Ru;Yuan, Fuh-Gwo
    • Steel and Composite Structures
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    • 제31권6호
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    • pp.641-653
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    • 2019
  • In this paper, wave propagation is studied and analyzed in double-layered nanotubes systems via the nonlocal strain gradient theory. To the author's knowledge, the present paper is the first to investigate the wave propagation characteristics of double-layered porous nanotubes systems. It is generally considered that the material properties of nanotubes are related to the porosity and hygro-thermal effects. The governing equations of the double-layered nanotubes systems are derived by using the Hamilton principle. The dispersion relations and displacement fields of wave propagation in the double nanotubes systems which experience three different types of motion are obtained and discussed. The results show that the phase velocities of the double nanotubes systems depend on porosity, humidity change, temperature change, material composition, non-local parameter, strain gradient parameter, interlayer spring, and wave number.

복식에 표현된 그로테스크 이미지의 형성 요인에 관한 연구 (A Study on the Formation Factors of Grotesque Image expressed in Fashion)

  • 남미현
    • 한국의상디자인학회지
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    • 제4권3호
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    • pp.43-54
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    • 2002
  • Some factors had influence upon the grotesque image formation expressed in fashion: for instance, thanatos, religions, fin de siecle (end of the century), the aesthetics of ugliness, subculture group's resistance and technology development, etc. Those factors have formed a grotesque while exchanging influence each other, and have following features: First, the thanatos, which is destructive and aggressive instinct of the inner world of human being, creates frightening object and motif to form the images of grotesque. Second, from religious point of view, the church made the Devil a tool for maintenance of power: They manipulated physical body and give a damage to it to sublimate it in holy existence, so that they could feel catharsis. Third, there was fin de siecle (end of the century) to let people have negative life attitude, such as uneasiness on following century, eschatology, skepticism and nihilism, etc. Fourth, the ugliness having unpleasantness and disharmony occupies governing position when our society becomes corrupted and uneasy, and the aesthetics of ugliness discloses the inconsistency of ideal and beautiful life in the grotesque images. Fifth, subculture groups, i.e., the lower classes, homosexual and the youth's group, etc, form the grotesque images by political and ideological resistance, complaints and specific identity, etc concerning governing culture keeping traditional ethics consciousness. Sixth, recent technology development has destroyed a boundary between human being and machinery, and bio-technology development has created transplant operation, plastic operation and other human body transformation operations, and genome research, etc has raised human being's identity.

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Computed tomographic features of the temporomandibular joint in 10 Jeju horses

  • Lee, Seyoung;Lee, Eun-Bee;Park, Kyung-Won;Jeong, Hyohoon;Shin, Kwang-Yun;Kweon, Young-Park;Seo, Jong-pil
    • Journal of Veterinary Science
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    • 제23권3호
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    • pp.44.1-44.10
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    • 2022
  • Background: The equine temporomandibular joint (TMJ) has a complex anatomical structure that makes diagnosis of TMJ disorders difficult. Computed tomography (CT) is now available in equine medicine; hence, TMJ evaluation has become more convenient. Objectives: The objectives of this study were to describe the CT features of the TMJ in Jeju horses and to compare these features with those of Thoroughbreds. Methods: In this report, the TMJs of 10 Jeju horses (mean age: 4.5 ± 1.9 yr; mean body weight: 282.6 ± 40.3 kg) and 6 Thoroughbreds (mean age: 7.3 ± 1.6 yr; mean body weight: 479.7 ± 44.0 kg) were examined using CT. After CT scanning, the Hounsfield units (HU) and height to width ratio (H:W) of the mandibular condyle were measured. Results: The mean H:W in Jeju horses was significantly lower than that in Thoroughbreds. The mean HU in Jeju horses was lower than that in Thoroughbreds; however, the difference was not significant. The most frequent CT finding was an irregular medial margin of the mandibular condyle in both breeds. Conclusions: In this study, the shape of the mandibular condyle in Jeju horses was flatter than that in Thoroughbreds. This report could be useful in evaluating the TMJ in Jeju horses. Moreover, CT could be a pragmatic choice for the examination of the TMJ in horses.

제주특별자치도의 탄소중립 실효성 제고를 위한 사회환경교육 활성화 방안 (Plan to revitalize social and environmental education to improve the effectiveness of carbon neutrality in Jeju Special Self-Governing Province)

  • 문경삼;하태현
    • 디지털융복합연구
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    • 제22권1호
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    • pp.1-14
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    • 2024
  • 본 연구는 제주특별자치도의 탄소중립 실효성 제고를 위헤 도내 초·중·고에서 실시하고 있는 학교 환경교육은 제외하고, 사회 환경교육의 실태를 문헌연구를 통해 파악하여 부족한 점 또는 문제점을 도출하고, 사회 환경교육을 체계적이고 통합적으로 운영하는 방안을 구축하는 데 목적이 있으며, 도출된 방안은 탄소중립 실효성 제고를 위해 환경에 대한 인식 전환과 친환경적 행동 유도의 지침서로 활용할 수 있을 것이다. 연구 결과 제주특별자치도는 현재 위탁 중인 환경교육센터의 내실 있는 운영과 지원을 통해 도내에 분산 운영되고 있는 환경교육 기관·단체 및 전문가 그룹과 협의체를 구축하여 환경교육 정책수립에 필요한 현황 파악, 콘텐츠 개발, 정보공유, 역할 분담과 정기적 소통·공감 및 정책 피드백이 이루어 질 수 있도록 플랫폼을 구축하고 환경문제를 올바르게 인식할 수 있도록 감성을 자극하고 환경문제를 자기화하는 현장을 중심으로 한 현장 환경교육의 필요성을 강조하고 있다.

생체유사환경 하의 치과용 임플란트의 피로강도 평가 및 수명 향상법 (Fatigue Strength of Dental Implant in Simulated Body Environments and Suggestion for Enhancing Fatigue Life)

  • 김민건
    • 대한기계학회논문집A
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    • 제38권3호
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    • pp.259-267
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    • 2014
  • 치과용 임플란트를 대상으로 하여 건전환경 및 생체 내의 인자들을 유사하게 반영한 생체유사환경 하에서 피로시험을 수행하였다. 생체유사환경으로는 링거액 환경과 인공타액환경을 각각 사용하였다. 우선 건전환경과 생체유사환경 하에서의 피로수명 및 피로한도를 평가하였다. 또한 피로수명을 향상시킬 수 있는 한 가지 방법을 제안하였다. 인공타액 하에서의 피로수명이 링거환경보다 대체적으로 감소하였다. 시편에 대한 부식작용은 인공타액이 링거액보다 훨씬 크다. 이러한 부식의 차이가 두 경우의 피로수명의 차이로 나타난 것으로 판단된다. 질화처리된 지대주 나사의 질화경화층을 제거하고, 질소확산층을 최표면으로 하는 지대주 나사를 사용한 임플란트의 피로수명은 텅스텐카바이드를 코딩한 기존 제품에 비해 최대 8배의 피로수명 향상효과가 확인되었다.

H-S 유동의 점성효과를 고려한 원심압축기 회전차내부의 준3차원 유동해석 (Quasi-3-Dimensional Analysis of Compressible Flow within a Blade Row Including Viscous Effect in H-S Flow)

  • 오종식;조강래
    • 대한기계학회논문집
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    • 제18권12호
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    • pp.3287-3296
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    • 1994
  • For the numerical computation of three-dimensional compressible flow field within a blade row in a centrifugal compressor, a quasi 3-dimensional solver which combines a reversible B-B flow and an irreversible H-S flow using finite element methods was developed. In a reversible B-B flow, the governing coordinates are modified in order to be applied to any type of turbomachinery, and two kinds of stream functions are introduced in order to make the Kutta condition exactly satisfied. In an irreversible H-S flow, the changes of entropy in the irreversible governing equations are determined not by empirical source but by the theoretical treatment of dissipation forces. The dissipation forces are obtained from the distribution of shear stresses in the flow passage which are given from the wall shear stresses using the exponential functions. A more accurate quasi-3-dimensional solver is established where the effect of body forces is involved in the non-axisymmetric H-S flow. Some numerical results obtained from authors' previous studies for axial flow machines assure that the present method is able to predict well as long as the flow is subsonic and not under strong viscous effect.