• Title/Summary/Keyword: Quasi-dimensional

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REFLECTIONS OF COMPLETELY REGULAR AND ZERO-DIMENSIONAL QUASI-ORDERED SPACES

  • Shin, Seon-Ho
    • The Pure and Applied Mathematics
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    • v.10 no.1
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    • pp.25-35
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    • 2003
  • We study equivalent definitions and some categorical properties of completely regular quasi-ordered spaces and zero-dimensional quasi-ordered spaces. Using the o-completely regular (resp. o-zero-dimensional) filters on a completely regular (resp. zero-dimensional) quasi-ordered space, we show that the category COMPOS (resp. ZCOMPOS) of compact (resp. compact zero-dimensional) partially ordered spaces is reflective in the category CRQOS (resp. ZQOS) of completely regular (resp. zero-dimensional) quasi-ordered spaces and continuous isotones.

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3-Dimensional Trans-Sasakian Manifolds with Gradient Generalized Quasi-Yamabe and Quasi-Yamabe Metrics

  • Siddiqi, Mohammed Danish;Chaubey, Sudhakar Kumar;Ramandi, Ghodratallah Fasihi
    • Kyungpook Mathematical Journal
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    • v.61 no.3
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    • pp.645-660
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    • 2021
  • This paper examines the behavior of a 3-dimensional trans-Sasakian manifold equipped with a gradient generalized quasi-Yamabe soliton. In particular, It is shown that α-Sasakian, β-Kenmotsu and cosymplectic manifolds satisfy the gradient generalized quasi-Yamabe soliton equation. Furthermore, in the particular case when the potential vector field ζ of the quasi-Yamabe soliton is of gradient type ζ = grad(ψ), we derive a Poisson's equation from the quasi-Yamabe soliton equation. Also, we study harmonic aspects of quasi-Yamabe solitons on 3-dimensional trans-Sasakian manifolds sharing a harmonic potential function ψ. Finally, we observe that 3-dimensional compact trans-Sasakian manifold admits the gradient generalized almost quasi-Yamabe soliton with Hodge-de Rham potential ψ. This research ends with few examples of quasi-Yamabe solitons on 3-dimensional trans-Sasakian manifolds.

CLASSIFICATION OF THREE-DIMENSIONAL CONFORMALLY FLAT QUASI-PARA-SASAKIAN MANIFOLDS

  • Erken, Irem Kupeli
    • Honam Mathematical Journal
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    • v.41 no.3
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    • pp.489-503
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    • 2019
  • The aim of this paper is to study three-dimensional conformally flat quasi-para-Sasakian manifolds. First, the necessary and sufficient conditions are provided for three-dimensional quasipara-Sasakian manifolds to be conformally flat. Next, a characterization of three-dimensional conformally flat quasi-para-Sasakian manifold is given. Finally, a method for constructing examples of three-dimensional conformally flat quasi-para-Sasakian manifolds is presented.

The Derivation of Generalized Quasi-Three Dimensional Displacement Field Equations for the Analysis of Composite Laminates (복합재료 적층판의 해석을 위한 일반화 준 3차원 변위식의 도출)

  • 김택현
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.4
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    • pp.21-27
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    • 1998
  • In the case of existing in free-edge delaminations of composite laminates which are symmetry with respect to mid-plane in laminates also, in the case of asymmetry and anti-symmetry, the generalized quasi-three dimensional displacement field equations developed from quasi-three dimensional displacement field equations can be applied to solve above cases. We introduce three paramenters in this paper, which have not been used in quasi-three dimensional displacement field equations until now. To the laminate subjected to the axial extension strain $\varepsilon$0(C1) in $\chi$-direction, the bending deformation $\chi$$\chi$(C$_2$) around у-direction, the bending deformation w$\chi$(C$_4$) around z-direction and the twisting deformation $\chi$$\chi$y(C$_3$) around $\chi$-direction .The generalized quasi-three dimensional displacement field equations are able to be analyzed efectively.

Calculation of 3-Dimensional Flow Through an Impeller of Centrifugal Compressor (원심압축기 회전차 내부의 3차원 유동해석)

  • ;;Kang, S. H.;Jeon, S. G.
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.10
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    • pp.2617-2629
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    • 1995
  • The flow through a centrifugal compressor rotor was calculated using the quasi-3-dimensional and fully 3-dimensional Navier-Stokes solution methods. The calculated results, obtained during the development of the computer codes for both methods are discussed. In the inviscid quasi 3-dimensional analysis, stream function formulation was used for the blade to blade (B-B) plane calculations, and the streamline curvature method was used for the meridional (H-S) plane calculations. In the viscous 3-dimensional flow analysis, a control volume method based on a general rotating curvilinear coordinate system was used to solve the time-averaged Navier-Stokes equations, and a standard k-.epsilon. model was used to obtain eddy viscosity. The quasi-3-dimensional analysis reasonably predicts the pressure distributions and requires much less computation time in the region where viscous effects are not strong; however, it fails to predict velocity field and loss mechanism through the impeller passage. The viscous 3-dimensional flow analysis shows reasonable pressure distributions and typical jet-wake flow field through the impeller passage. Secondary flow and total pressure distributions on cross-sectional planes explain the loss mechanisms through the impeller.

Effective Boundary Conditions for FEM Analysis of Composite Laminates (복합재료 적층판의 유한요소 해석을 위한 효율적 경계조건)

  • 김택현
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.3
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    • pp.92-98
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    • 1998
  • This paper presents three boundary techniques which are useful for FEM analysis of composite laminates: 1) a rotational symmetric boundary technique . 2) a quasi three-dimensional boundary technique and 3) a contact boundary technique. The use of the rotational symmetric boundary technique is possible for a smaller FEM model. With the use of the quasi three-dimensional boundary tecnique. quasi three dimensional analysis of composite laminates can be performed on the conventional 3-D FEM program These techniques can readily be adopted to FEM programs.

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Design Sensitivity in Quasi-One-Dimensional Silicon-Based Photonic Crystalline Waveguides

  • Kinoshita, Takeshi;Shimizu, Akira;Iida, Yukio;Omura, Yasuhisa
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.3 no.1
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    • pp.55-61
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    • 2003
  • This paper describes how the optical properties of a quasi-one-dimensional photonic crystalline waveguide having a periodic air cavity are influenced by various structural parameters; the electromagnetic fields are simulated using the finite-difference time-domain method. The simulations considered four design parameters: cavity size, defect size, lattice constant, and number of cavity. The parameter sensitivity of the photonic bandgap property of the waveguide having air cavities is examined. A couple of significant design guidelines are obtained. We show that the quasi-one-dimensional photonic crystalline waveguide has significant unrealized potential.

Reduced Quasi-Dimensional Combustion Model of the Direct Injection Diesel Engine for Performance and Emissions Predictions

  • Jung, Dohoy;Assanis, Dennis N.
    • Journal of Mechanical Science and Technology
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    • v.18 no.5
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    • pp.865-876
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    • 2004
  • A new concept of reduced quasi-dimensional combustion model for a direct injection diesel engine is developed based on the previously developed quasi-dimensional multi-zone model to improve the computational efficiency. In the reduced model, spray penetration and air entrainment are calculated for a number of zones within the spray while three zones with aggregated spray zone concept are used for the calculation of spray combustion and emission formation processes. It is also assumed that liquid phase fuel appears only near the nozzle exit during the breakup period and that spray vaporization is immediate in order to reduce the computational time. Validation of the reduced model with experimental data demonstrated that the new model can predict engine performance and NO and soot emissions reasonably well compared to the original model. With the new concept of reduced model, computational efficiency is significantly improved as much as 200 times compared to the original model.