Abstract: An oxidation resistant, non-consumable anode, for use in the electrolytic reduction of alumina to aluminum, has a composition comprising copper, nickel and iron. The anode is part of an electrolytic reduction cell comprising a vessel having an interior lined with metal which has the same composition as the anode. The electrolyte is preferably composed of a eutectic of AlF.sub.3 and either (a) NaF or (b) primarily NaF with some of the NaF replaced by an equivalent molar amount of KF or KF and LiF.

Abstract: Finely divided particles of alumina are electrolytically reduced to aluminum in an electrolytic reduction vessel having a plurality of vertically disposed, non-consumable anodes and a plurality of vertically disposed, dimensionally stable cathodes in closely spaced, alternating arrangement with the anodes. A horizontally disposed, gas bubble generator is located at the vessel bottom, underlying the cathodes and the spaces between each pair of adjacent electrodes. The vessel contains a molten electrolyte bath composed of (1) NaF+Alf.sub.3 eutectic, (2) KF+AlF.sub.3 eutectic and (3) LiF. The alumina particles are maintained in suspension in the molten electrolyte bath by rising gas bubbles generated at the anodes and at the gas bubble generator during the reduction process.

Abstract: A cell for the electrolytic reduction of alumina to aluminum comprises an electrolyte bath composed of halide salts having a density greater than aluminum but less than alumina. A non-consumable anode is located at the bottom of the bath, and a dimensionally stable cathode coated with titanium diboride is spaced above the anode and totally immersed in the bath. Particles of alumina are introduced into the bath where the alumina dissolves and forms ions of aluminum and oxygen. The oxygen ions are converted at the anode to gaseous oxygen which bubbles upwardly through the bath, agitating the bath. As a result, the bath is substantially saturated with dissolved alumina in the region of the anode, and the build-up of a layer of undissolved alumina on the anode is prevented. The aluminum ions are converted to metallic aluminum at the cathodes, and molten aluminum accumulates as a pool atop the bath above the cathodes.

Abstract: Ion exchange resins can be prepared by co-polymerizing a major amount (>88 mol %) of non-ionic acrylic monomer, such as methyl methacrylate, with a minor amount (3 to 12 mol %) of an ionogenous monomer such as methacrylamidopropyltrimethylammonium chloride or 2-acrylamido-2-methyl propane sulfonic acid. The resultant anion-conductive or cation conductive membranes exhibit low swelling in water and high ion-transference numbers. The membranes may be applied as coatings on neural prosthesis electrodes.

Abstract: A shaft rotatably mounted within a housing. The shaft extends through a pair of annular seal elements one of which is mounted on the shaft for rotation therewith. The other seal element is associated with the housing and is stationary relative to the shaft. The seal elements have respective mating surfaces which rub together during rotation of the shaft. One seal element is composed of relatively hard material, and the other seal element is composed of relatively soft material so that the mating surface of the latter is conformed to the mating surface of the former when the two mating surfaces are initially rubbed together. There is a minute gap between the mating surfaces, and this gap contains a film of liquid which acts as a lubricant. Both seal elements are composed of a material which will not support an electrochemical reaction, e.g., an electrically insulating material, to prevent electrokinetic corrosion of the mating surfaces when the film therebetween is an electrolytic liquid.

Abstract: A prosthesis electrode for electrically stimulating body tissue. The electrode has a metal tip covered by a non-metallic coating composed of a compound of the metal in the tip. Covering the non-metallic coating is an ion-conducting membrane which prevents the metal tip and the non-metallic coating from contacting the body tissue. The membrane comprises a specific ion-conducting inner membrane layer which prevents transference to the body tissue of ions in the coating which enter into undesirable reactions with the body tissue. On the outside of the inner membrane is a non-specific ion-conducting outer membrane layer which is non-toxic to body tissue and which prevents changes in salt concentration in the body tissue adjacent the electrode during a biphasic pulse of the electrode.