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A quench is the transition from a superconducting state to a normal conducting state. Elucidating the mechanism of quenching caused by mechanical disturbances (training quench) requires a detailed understanding of the stress state in the coil during excitation. In this study, we developed a large-scale analysis method that can precisely analyze where strain energy is concentrated and loss energy is generated due to thermal stress and electromagnetic force in superconducting coils by considering the detailed structure of superconducting wires and the wire alignment disorder caused by constraints during winding. The results showed that strain energy in the resin is concentrated in the region of overlap between the strain energy distribution caused by the macroscopic deformation of the coil and the geometrically inhomogeneous region, including the wire transfer zone. Furthermore, comparative verification using acoustic emission measurements to determine damage locations suggests that quench is also concentrated at the transfer zone in the actual coil, thus demonstrating the validity of the analysis. A sub-model of the area around the transfer zone, which was found in the large-scale analysis, was created, and crack propagation analysis was conducted using the phase-field method. Crack propagation in the resin and increased deformation of the wire due to weakening of the supporting rigidity of the wire caused by the crack propagation were observed.

The Centrifuge Rotor (CR) is an artificial gravity generator, which is aiming at launch in 2006 as a portion of the life science experimental facility of the International Space Station (ISS). The CR rotates habitats located radially around the axis and generates centrifugal force, imposing artificial gravity of arbitrary magnitude up to 22.0 m/s2 (about 2.2 g) on the specimens housed in the habitats. The imbalance is caused by the asymmetry of two habitats opposite each other, which brings about change in the mass of the habitats as well as the quasi-static change of the CG of plants and fluids and the dynamic rodent motions in the habitats. The active mass Auto-Balancing System (ABS) is provided for automatic canceling of the above-mentioned imbalance of the rotor. This paper presents the concept and the test results of the ABS.

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