Kentaro Takase

A study on the relaxation of levitation property in an HTSC magnetic bearing

Abstract For realization of the flywheel system using high T c superconductors (HTSCs), AC loss is one of the serious problems to be solved. An un-uniformity of magnetization of permanent magnets rotating at high speed generates AC field around HTSC. This causes AC losses. In this study we assumed that AC field generated by a rotating permanent magnet is equivalent to AC field generated by coil current. Based on this model the experiments were done. These results were compared with those of numerical simulation. Furthermore, to suppress AC loss, a pre-loading method was suggested.

Numerical simulation of fluxoid dynamics in low tc and high tc superconductors

In this study a numerical method was developed to simulate behavior of fluxoids developing two models of a 2-dimensional and a pancake fluxoid based on the FD (Fluxoid Dynamics) method, a combination of two concepts: the molecular dynamics method and the Ginzburg-Landau equation. The macroscopic electromagnetic phenomena, such as critical current density, were predicted by this method, and the results were compared with the well-known empirical ones.

Non-destructive sizing method for ball bearing flaking

This paper proposes a new non-destructive method for evaluating the size of the flaking in ball bearing with an electromagnetic sensor. This method focuses on the variation of the magnitude of the characteristic frequency of a defect on the outer race. Through the presence of local maximums and minimums, the length of the flaking is evaluated while the bearing is in operation. The applicability and accuracy of this method is confirmed through several accelerated aging tests. It is shown that the growth of the length of the flaking in ball bearings is linear.

Numerical Simulation of Fluxoid Behaviors in Bi2212 Single Crystal

The numerical method was developed to simulate behavior of the fluxoids in Bi-2212 single crystal. This method is based on a combination of two concepts: the Molecular Dynamics (MD) and Ginzburg-Landau (GL) theory. Several macroscopic electromagnetic phenomena were predicted by this method, and the results agreed well with the well-known empirical ones.

Simulation of Magnetization of Bi2212 Single Crystal by the Fluxoid Dynamics Method

In this study the Fluxoid Dynamics (FD) method was developed to simulate the mesoscopic behavior of the fluxoids in a Bi2212 single crystal. This method is based on a combination of two concepts; the Molecular Dynamics (MD) and the Ginzburg-Landau (G-L) theory. The aim of this study is to predict the macroscopic electromagnetic phenomena by simulating the mesoscopic behavior of many fluxoids.

Fluxoid dynamics methods for electromagnetic phenomena of superconductors

In this study the numerical method was developed to simulate behavior of the fluxoids in NbTi and Bi‐2212. The method was named the Fluxoid Dynamics (FD) method, and is based on a combination of two concepts : the Molecular Dynamics (MD) and Ginzburg‐Landau (G‐L) theory. Several macroscopic electromagnetic phenomena were predicted by these methods, and the results were compared with the well‐known empirical ones.