Abstract: A device for the determination of residual stress in a material sample consisting of a sensor coil, adjacent the material sample, whose resistance varies according to the amount of stress within the material sample, a mechanical push-pull machine for imparting a gradually increasing compressional and tensional force on the material sample, and an impedance gain/phase analyzer and PC for sending an input signal to and receiving an input signal from the sensor coil. The PC will measure and record the change in resistance of the sensor coil and the corresponding amount of strain of the sample. The PC will then determine from the measurements of change of resistance and corresponding strain of the sample the point at which the resistance of the sensor coil is at a minimum and the corresponding value and type of strain of the sample at that minimum resistance point thereby enabling a calculation of the residual stress in the sample.

Abstract: A superconducting bearing for a rotating member having a magnet at each extremity of the rotating member; having a bearing made of a material exhibiting Type II superconducting properties, the bearing is formed as a recess in the superconducting material in the form of a cylindrical, closed-end orifice. The bearing exerts levitation forces on the magnets at each extremity of the rotating member. Several methods for controlling the levitation forces exerted by the bearing on the magnets at each extremity of the rotating member are shown. One method is to construct the bearing from two different types of superconducting materials. Another method is to provide heating elements in the bearing. A further method is to provide an electromagnetic coil above the bearing. The bearing could also be segmented or have material removed to control the levitation forces.