Abstract: A stress-strain test for conductors. A test assembly receives first and second conductive layers and a dielectric layer adjacent each of the conductive layers. The layers are generally ring-shaped and concentric when received by the test assembly and the dielectric layer separates the conductive layers from each other. A magnetic field source provides a magnetic field to the test assembly and a variable current source provides current to the second conductive layer. A circuit measures a change in capacitance between the conductive layers when the current in the second conductive layer is varied whereby the stress and strain characteristics of the second conductive layer are determined as a function of the capacitance change.

Abstract: A process for the production of a YBa.sub.2 Cu.sub.3 O.sub.7-x or YBa.sub.2 Cu.sub.3 O.sub.7-x -AgO superconductor includes: providing the appropriate powder or mix of powders, pressing the powder to form the desired specimen, sintering the specimen to achieve fusion of the powder, heat treating the sintered specimen, and subjecting the specimen to an oxygenation process. The material exhibits bifurcation in its critical current density versus temperature curve.

Abstract: A device having superconductive and resistive states including an element comprising a high temperature superconductive material having a first (high) state with a first (high) critical current density and having a second (low) state with a second (low) critical current density, wherein the second (low) critical current density is less than the first (high) critical current density. A transient pulse generator applies a transient pulse to the element. The transient pulse changes the state of the element between the first (high) and second (low) states, the element being superconductive in the first (high) state, and the element being resistive in the second (low) state. A YBa.sub.2 Cu.sub.3 O.sub.7-x or YBa.sub.2 Cu.sub.3 O.sub.7-x -Ag compound exhibiting bifurcation of its critical current density versus temperature curve. A process for the production of a YBa.sub.2 Cu.sub.3 O.sub.7-x or YBa.sub.2 Cu.sub.3 O.sub.