• Title/Summary/Keyword: Governing the Body

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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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    • v.31 no.6
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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.

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

  • 주영철;박권현
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.3
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    • pp.368-375
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    • 1987
  • Effective thermal conductivity of the porous nuclear fuel has been investigated numerically. Difficulties associated with irregular shape of pore have been overcome by using the Body Fitted Coordinate Systems. A computer code has been developed to solve the governing equation with appropriate boundary conditions by transforming from the Cartesian coordinates to the nonorthogonal curvilinear coordinates. The effects of the porosity have been investigated. For a convenient use of the result, a correlation equation was suggested under the assumption of circular pore. The computation results by the assumption of randomly oriented elliptic pore has been agreed more closely to existing experimental result than that by the assumption of circular pore.

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

  • 왕지석;박태인
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.3
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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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A Study on the Plastic Spin of Body Centered Crystal (체심입방격자 단결정의 소성스핀에 관한 연구)

  • 남용윤;김사수
    • Journal of Ocean Engineering and Technology
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    • v.10 no.2
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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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A Study on Turbulent Flow Fields around Ships (선체주위 난류유동장의 해석에 관한 연구)

  • Lee S. H.;Park J. J.
    • Journal of computational fluids engineering
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    • v.1 no.1
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    • pp.64-70
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    • 1996
  • Three dimensional turbulent flow fields around ships are simulated by a numerical method. Reynolds Averaged Navier-Stokes equations are used where Reynolds stresses are approximated by Baldwin-Lomax and Sub-Grid Scale(SGS) turbulence models. Body-fitted coordinate system is introduced to conform three dimensional ship geometries. The governing equations are discretized by a finite volume method. Temporal derivatives are approximated by the forward differencing and the convection terms are approximated by the QUICK or Kawamura scheme. The 2nd-order centered differencing is used for other spatial derivatives. Pressure and velocity fields are simultaneously iterated by the Highly Simplified Marker-And-Cell method. To verify the numerical method and turbulence models, flow fields around ships are simulated and compared to the experiments.

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

  • 남미현
    • Journal of the Korea Fashion and Costume Design Association
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    • v.4 no.3
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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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    • v.23 no.3
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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.

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

  • Kyung-Sam Moon;Tai-Hyun Ha
    • Journal of Digital Convergence
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    • v.22 no.1
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    • pp.1-14
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    • 2024
  • In order to improve the effectiveness of carbon neutrality in Jeju Special Self-Governing Province, this study identifies the current state of social environmental education through literature research, excluding school environmental education being implemented in elementary, middle, and high schools in the province, and identifies shortcomings or problems. The purpose is to establish a plan to systematically and integratedly operate social environmental education, and the derived plan can be used as a guide to change environmental awareness and induce eco-friendly behavior to improve the effectiveness of carbon neutrality. As a result of the study, Jeju Special Self-Governing Province established a consultative body with environmental education institutions, organizations and expert groups operating dispersed throughout the province through the substantial operation and support of the environmental education center currently being entrusted, to identify the current status and develop content necessary for establishing environmental education policies, establishing a platform to enable information sharing, role division, regular communication, empathy, and policy feedback, and on-site environmental education centered on the field to stimulate emotions and personalize environmental problems so that environmental problems can be properly recognized. Emphasizing the necessity.

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

  • Kim, Min Gun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.3
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    • pp.259-267
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    • 2014
  • Fatigue tests were performed in various simulated body environments reflecting various factors (such as body fluids, artificial saliva) relevant within a living body. First, the fatigue limit under a simulated body environment (artificial saliva) was evaluated and the governing factors of implant fatigue strength were looked into by observing the fracture mode. The fatigue life of an implant decreased in the artificial saliva environment compared with that in the ringer environment. Furthermore, in the artificial saliva environment, the implant fracture mode was fatigue failure of fixture as opposed to the abutment screw mode in the ringer environment. In the fatigue test, corrosion products were observed on the implant in the simulated body environment. A larger amount of corrosion products were generated on the artificial saliva specimen than on the ringer specimen. It is thought that the stronger corrosion activity on the artificial saliva specimen as compared with that on the ringer specimen led to an overall decrease of fatigue life of the former specimen. In the case of the implant with a nitrided abutment screw eliminated hardened layer (TixN), a several times increase in fatigue life is achieved in comparison with tungsten carbide-coated implants.

Three-dimensional stresses analysis in rotating thin laminated composite cylindrical shells

  • Ahmadi, Isa;Najafi, Mahsa
    • Steel and Composite Structures
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    • v.22 no.5
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    • pp.1193-1214
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    • 2016
  • In this paper, the 3D stress state and inter-laminar stresses in a rotating thin laminated cylinder shell are studied. The thickness of the cylinder is supposed to be thin and it is made of laminated composite material and can have general layer stacking. The governing equations of the cylindrical shell are obtained by employing the Layerwise theory (LWT). The effect of rotation is considered as rotational body force which is induced due to the rotation of the cylinder about its axis. The Layerwise theory (LWT), is used to discrete the partial differential equations of the problem to ordinary ones, in terms of the displacements of the mathematical layers. By applying the Free boundary conditions the solution of the governing equations is completed and the stress state, the inter-laminar stresses, and the edge effect in the rotating cylindrical shells are investigated in the numerical results. To verify the results, LWT solution is compared with the results of the FEM solution and good agreements are achieved. The inter-laminar normal and shear stresses in rotating cylinder are studied and effects of layer stacking and angular velocity is investigated in the numerical results.