Abstract: The training effect in superconducting coils is eliminated by winding the coil with a composite material that includes both a superconductor and a normal material and then applying stresses to the wound coil in the direction that electromagnetic stresses will be applied to the coil during normal use and in a magnitude greater than the calculated magnitude of the greatest electromagnetic stresses to be applied to the coil.

Abstract: A hydrostatic extrusion method and apparatus for the extrusion of tubes is disclosed wherein the simplified structure of the nose or tip portion of the billet and the cooperating surfaces of the die defining the die cavity and those of the mandrel facilitate an improved initial sealing among the associated surfaces of the die, billet and mandrel. Such an initial sealing is effected between such interfaces of the members and billet at a point which is located substantially rearwardly from the position at which the actual extrusion to the final tubular configuration occurs between the bearing portion of the die and the cooperating sizing portion of the mandrel. Such structure and method permits the extrusion of tubes having walls of asymmetric or non-circular configurations in cross section, even those of complex configurations.

Abstract: Method and apparatus for driving an interference-fit fastener by electromagnetically generating a stress wave, conditioning the stress wave, and passing the stress wave through the fastener, the stress wave is reflected from the remote free end of the fastener to impart a high velocity to the fastener relative to the surface of its receiving aperture to overcome the frictional forces existing there between and draw the interference fastener into the receiving aperture.

Abstract: This invention provides a method of securing the tube ends of a plurality of explosively expandable metal tubes to a tube plate in which the tubes are inserted utilizing explosive cartridges equipped with a heat sensitive means. The heat sensitive means is in operative proximity to the explosive charges. There are also provided heating means capable of effectively heating the heat sensitive means. Expansion of the tubes located at multiple positions is effected by successively exploding the charges by the application of heat energy to the heat sensitive means.