Daido University

About: Daido University is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Ultimate tensile strength & Proton exchange membrane fuel cell. The organization has 209 authors who have published 423 publications receiving 3223 citations.

Proposal of fundamental items for social survey on noise problems

Abstract: Seiichiro Namba , Sonoko Kuwano1;, Jiro Kaku2;, Kazuhiro Kuno3;, Minoru Sasaki4;, Hideki Tachibana5;, Akihiro Tamura , Yoshiaki Mishina7;, Takashi Yano8; and Ichiro Yamada9; Professor Emeritus of Osaka University Kobayasi Institute of Physical Research Aichi Institute of Technology Professor Emeritus of Kyushu Institute of Design Yokohama National University Chiba Institute of Technology Daido University Kumamoto University Airport Environment Improvement Foundation

de Sitter thermodynamics in the canonical ensemble

Abstract: The existing thermodynamics of the cosmological horizon in de-Sitter spacetime is established in the micro-canonical ensemble, while thermodynamics of black hole horizons are established in the canonical ensemble. Generally in the ordinary thermodynamics and statistical mechanics, both of the micro-canonical and canonical ensembles yield the same equation of state for any thermodynamic system. This implies the existence of a formulation of de-Sitter thermodynamics based on the canonical ensemble. This paper reproduces the de-Sitter thermodynamics in the canonical ensemble. The procedure is as follows: We put a spherical wall at the center of de-Sitter spacetime, whose mass is negligible and perfectly reflects the Hawking radiation coming from the cosmological horizon. Then the region enclosed by the wall and horizon settles down to a thermal equilibrium state, for which the Euclidean action is evaluated and the partition function is obtained. The integration constant (subtraction term) of Euclidean action is determined to reproduce the equation of state (e.g. entropy-area law) verified already in the micro-canonical ensemble. Our de-Sitter canonical ensemble is well-defined to preserve the "thermodynamic consistency", which means that the state variables satisfy not only the four laws of thermodynamics but also the appropriate differential relations with thermodynamic functions; e.g. partial derivatives of the free energy give the entropy, pressure, and so on. The special role of cosmological constant in de-Sitter thermodynamics is also revealed.

High Strength/High Strain Tolerance DI-BSCCO Tapes by Means of Pre-Tensioned Lamination Technique

Abstract: Excellent high tolerance on the yield stress and critical current of BSCCO-Bi2223 tapes was realized by the pretensioned lamination technique. The yield stress at room temperature and the stress to 95% Ic retention exceeded 430 and 510 MPa, respectively. In order to make clear the potential of this technique, the influence of thickness of lamination sheet and degree of pretension was investigated in detail. The observed yield stress at which the macroscopic yielding starts due to the fracture of BSCCO filaments has been successfully evaluated by calculation as a function of stainless steel sheet thickness and pretension, which is useful as engineering data. The relaxation stress at which the local strain starts to relax due to filament fracture was expressed as a unique function of the thermal residual strain exerted on BSCCO filaments together with the residual strain induced by the pretension treatment. The force free stress at which the local stress exerted BSCCO filaments becomes zero was proportional in magnitude to the residual strain exerted on BSCCO filaments. The stress to 95% Ic retention was elucidated to give a good indication, at which the critical current decreases abruptly due to the fracture of BSCCO filaments.