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Nozawa S.,Josai Junior College | Kohyama Y.,Advanced Simulation Technology of Mechanics Co.
Monthly Notices of the Royal Astronomical Society | Year: 2014

We study the Sunyaev-Zeldovich effect for clusters of galaxies. The Boltzmann equations for the cosmic microwave background photon distribution function are studied in three Lorentz frames.We extend the previous work and derive analytic expressions for the integrated photon redistribution functions over the photon frequency. We also derive analytic expressions in the power series expansion approximation. By combining two formulas, we offer a simple and accurate tool to analyse observation data. These formulas are applicable to the non-thermal electron distributions as well as the standard thermal distribution. The Boltzmann equation is reduced to a single integral form of the electron velocity. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Nozawa S.,Josai Junior College | Kohyama Y.,Advanced Simulation Technology of Mechanics Co.
Astroparticle Physics | Year: 2015

We study the Sunyaev-Zeldovich effect for clusters of galaxies. We explore the relativistic corrections to the Kompaneets equation in terms of two different expansion approximation schemes, namely, the Fokker-Planck expansion approximation and delta function expansion approximation. We show that two expansion approximation formalisms are equivalent under the Thomson approximation, which is extremely good approximation for the CMB photon energies. This will clarify the situation for existing theoretical methods to analyse observation data. © 2014 Elsevier B.V. All rights reserved.

Sun Z.,RIKEN | Sun Z.,Advanced Simulation Technology of Mechanics Co. | Teodosiu C.,RIKEN | Teodosiu C.,Advanced Simulation Technology of Mechanics Co. | And 4 more authors.
Nihon Kikai Gakkai Ronbunshu, A Hen/Transactions of the Japan Society of Mechanical Engineers, Part A | Year: 2011

To make effective use of the VCAD-based software for the generation of degenerated hexahedral element models (V-DualGrid) and structural analysis of elastoplastic materials(V-Struct) in complicated engineering applications, a class of complex elements which are constructed by using the low-order convex elements(called child elements) such as 4-node tetrahedra and 5-node pyramids generated by the division of concave elements in V-DualGrid is developed and implemented to V-Struct. The basic idea employed in the formulation of the complex elements is to use an extended B-bar method to enforce the near-incompressibility constraint to the level of the complex elements in order to effectively avoid the so-called volumetric locking occurred in their child elements, and eventually to enable the successful use of the child elements in elastoplastic analysis. Two analyses for benchmark test and an analysis using a FE model generated actually by V-DualGrid are given to show the good performance of the new complex elements. © 2011 The Japan Society of Mechanical Engineers.

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