• Title/Summary/Keyword: Quasi-deals

Search Result 57, Processing Time 0.024 seconds

QUASI-CONFORMAL CURVATURE TENSOR ON N (k)-QUASI EINSTEIN MANIFOLDS

  • Hazra, Dipankar;Sarkar, Avijit
    • Korean Journal of Mathematics
    • /
    • v.29 no.4
    • /
    • pp.801-810
    • /
    • 2021
  • This paper deals with the study of N (k)-quasi Einstein manifolds that satisfies the certain curvature conditions 𝒞*·𝒞* = 0, 𝓢·𝒞* = 0 and ${\mathcal{R}}{\cdot}{\mathcal{C}}_*=f{\tilde{Q}}(g,\;{\mathcal{C}}_*)$, where 𝒞*, 𝓢 and 𝓡 denotes the quasi-conformal curvature tensor, Ricci tensor and the curvature tensor respectively. Finally, we construct an example of N (k)-quasi Einstein manifold.

QUASI AND BI IDEALS IN LEFT ALMOST RINGS

  • Hussain, Fawad;Khan, Walayat;Khan, Muhammad Sajjad Ali;Abdullah, Saleem
    • Honam Mathematical Journal
    • /
    • v.41 no.3
    • /
    • pp.449-461
    • /
    • 2019
  • The aim of this paper is to extend the concept of quasi and bi-ideals from left almost semigroups to left almost rings which are the generalization of one sided ideals. Further, we discuss quasi and bi-ideals in regular left almost rings and intra regular left almost rings. We then explore many interesting and elegant properties of quasi and bi-ideals.

A Single-Phase Quasi Z-Source Dynamic Voltage Restorer(DVR) (단상 Quasi Z-소스 동적전압보상기(DVR))

  • Lee, Ki-Taeg;Jung, Young-Gook;Lim, Young-Cheol
    • The Transactions of the Korean Institute of Power Electronics
    • /
    • v.15 no.4
    • /
    • pp.327-334
    • /
    • 2010
  • This paper deals with a single-phase dynamic voltage restorer(DVR) with a quasi Z-source topology. The proposed system based on a single-phase quasi Z-source PWM ac-ac converter which have features such as the input voltage and output voltage are sharing ground, and input current operates in continuous current mode(CCM). For the detection of voltage sag-swell, peak voltage detection method is applied. Also, the circuit principles of the proposed system are described. During the 60% severe voltage sag and 30% voltage swell, the proposed system controls the adding or missing voltage and maintains the rated voltage of sinusoidal waveform at the terminals of the critical loads. Finally, PSIM simulation and experimental results are presented to verify the proposed concept and theoretical analysis.

QUASI-LIKELIHOOD REGRESSION FOR VARYING COEFFICIENT MODELS WITH LONGITUDINAL DATA

  • Kim, Choong-Rak;Jeong, Mee-Seon;Kim, Woo-Chul;Park, Byeong-U.
    • Journal of the Korean Statistical Society
    • /
    • v.33 no.4
    • /
    • pp.367-379
    • /
    • 2004
  • This article deals with the nonparametric analysis of longitudinal data when there exist possible correlations among repeated measurements for a given subject. We consider a quasi-likelihood regression model where a transformation of the regression function through a link function is linear in time-varying coefficients. We investigate the local polynomial approach to estimate the time-varying coefficients, and derive the asymptotic distribution of the estimators in this quasi-likelihood context. A real data set is analyzed as an illustrative example.

A NOTE ON (𝑘, 𝜇)'-ALMOST KENMOTSU MANIFOLDS

  • Yadav, Sunil Kumar;Mandal, Yadab Chandra;Hui, Shyamal Kumar
    • Honam Mathematical Journal
    • /
    • v.43 no.4
    • /
    • pp.571-586
    • /
    • 2021
  • The present paper deals with the study of generalized quasi-conformal curvature tensor inside the setting of (𝑘, 𝜇)'-almost Kenmotsu manifold with respect to 𝜂-Ricci soliton. Certain consequences of these curvature tensor on such manifold are likewise displayed. Finally, we illustrate some examples based on this study.

Quasi-3D analysis of Axial Flux Permanent Magnet Rotating Machines using Space Harmonic Methods (공간고조파법을 이용한 축 자속 영구자석 회전기기의 준(準)-3D 특성 해석)

  • Choi, Jang-Young
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.60 no.5
    • /
    • pp.942-948
    • /
    • 2011
  • This paper deals with characteristic analysis of axial flux permanent magnet (AFPM) machines with axially magnetized PM rotor using quasi-3-D analysis modeling. On the basis of magnetic vector potential and a two-dimensional (2-D) polar-coordinate system, the magnetic field solutions due to various PM rotors are obtained. In particular, 3-D problem, that is, the reduction of magnetic fields near outer and inner radius of the PM is solved by introducing a special function for radial position. And then, the analytical solutions for back-emf and torque are also derived from magnetic field solutions. The predictions are shown in good agreement with those obtained from 3-D finite element analyses (FEA). Finally, it can be judged that analytical solutions for electromagnetic quantities presented in this paper are very useful for the AFPM machines in terms of following items : initial design, sensitivity analysis with design parameters, and estimation of control parameters.

Quasi-Static Tests on SRC Composite Columns (SRC 합성교각의 준정적 실험)

  • Shim, Chang-Su;Chung, Young-Soo;Jung, In-Keun;Min, Jin;Han, Jung-Hun
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2005.11a
    • /
    • pp.299-302
    • /
    • 2005
  • This study deals with the quasi-static tests on steel reinforced concrete composite columns with single embedded steel or multiple members. For the design of bridge piers, the composite section needs to have low steel ratio for cost savings because the dimension of the pier section is usually large. There is lack of design guidelines for these composite columns with low steel ratio, but the design provisions for the normal reinforced concrete column can be used for the design because of the low steel ratio. It is necessary to provide the design provisions in terms of the strength limit state and seismic performance by the detail requirements on the longitudinal steel and the transverse steel. The test parameters in this study were determined considering the current design provisions on RC columns. Through the quasi-static tests, the seismic performance of the composite columns were discussed.

  • PDF

Numerical analysis of interference galloping of two identical circular cylinders

  • Blazik-Borowa, E.;Flaga, A.
    • Wind and Structures
    • /
    • v.1 no.3
    • /
    • pp.243-253
    • /
    • 1998
  • The paper deals with numerical analysis of interference galloping of two elastically supported circular cylinders of equal diameters. The basis of the analysis is quasi-steady model of this phenomenon. The model assumes that both cylinders participate in process of interference galloping and they have two degrees of freedom. The movement of the cylinders is written as a set of four nonlinear differential equations. On the basis of numerical solutions of this equations the authors evaluate the correctness of this quasi-steady model. Then they estimate the dependence of a critical reduced velocity on the Scruton number, turbulence intensity and arrangements of the cylinders.

Modeling of unilateral effect in brittle materials by a mesoscopic scale approach

  • Pituba, Jose J.C.;Neto, Eduardo A. Souza
    • Computers and Concrete
    • /
    • v.15 no.5
    • /
    • pp.735-758
    • /
    • 2015
  • This work deals with unilateral effect of quasi-brittle materials, such as concrete. For this propose, a two-dimensional meso-scale model is presented. The material is considered as a three-phase material consisting of interface zone, matrix and inclusions - each constituent modeled by an appropriate constitutive model. The Representative Volume Element (RVE) consists of inclusions idealized as circular shapes randomly placed into the specimen. The interface zone is modeled by means of cohesive contact finite elements developed here in order to capture the effects of phase debonding and interface crack closure/opening. As an initial approximation, the inclusion is modeled as linear elastic as well as the matrix. Our main goal here is to show a computational homogenization-based approach as an alternative to complex macroscopic constitutive models for the mechanical behavior of the quasi-brittle materials using a finite element procedure within a purely kinematical multi-scale framework. A set of numerical examples, involving the microcracking processes, is provided. It illustrates the performance of the proposed model. In summary, the proposed homogenization-based model is found to be a suitable tool for the identification of macroscopic mechanical behavior of quasi-brittle materials dealing with unilateral effect.

On the dispersion of waves propagating in "plate+fluid layer" systems

  • Akbarov, Surkay D.;Negin, Masoud
    • Coupled systems mechanics
    • /
    • v.10 no.2
    • /
    • pp.123-142
    • /
    • 2021
  • The paper deals with the study of the dispersion of quasi-Lamb waves in a hydro-elastic system consisting of an elastic plate, barotropic compressible inviscid fluid, and rigid wall. The motion of the plate is described using the exact equations of elastodynamics, however, the flow of the fluid using the linearized equations and relations of the Navier-Stokes equations. The corresponding dispersion equation is obtained and this equation is solved numerically, as a result of which the corresponding dispersion curves are constructed. The main attention is focused on the effect of the presence of the fluid and the effect of the fluid layer thickness (i.e., the fluid depth) on the dispersion curves. The influence of the problem parameters on the dispersion curves related to the quasi-Scholte wave is also considered. As a result of the analyses of the numerical results, concrete conclusions are made about the influence of the fluid depth, the rigid wall restriction on the fluid motion, and the material properties of the constituents on the dispersion curves. During the analyses, the zeroth and the first four modes of the propagating waves are considered.