Abstract: A high pressure sodium lamp brightness was increased 8.9%, its relative voltage stability was improved by a factor of 4, and its relative maintenance was improved by a factor of 3 over a 24,000 hour lifetest. These improvements were accomplished by the application of a fine grained alumina protctive coating on the surface of the polycrystalline alumina arc tube. The process for applying the protective coating comprises the deposition of Al(NO.sub.3).sub.3 from solution on the surface of the arc tube followed by the thermal decomposition of the Al(NO.sub.3).sub.3 to form an alumina coating on the surface of the alumina arc tube.

Abstract: A process for making a homogeneous metal oxide varistor powder is described. The ingredients desired in a varistor which are water and acid soluble and dissolved in water and acid respectfully to make a solution. The remaining ingredients which are water and acid insoluble are then suspended in the solution to make a homogeneous slurry. The slurry is dried, calcined, reslurried, dried, pressed and sintered. The sintered body has electrical leads attached then encapsulated in an epoxy resin to make an encapsulated varistor package.

Abstract: A process for making an encapsulated metal oxide varistor package comprises pressing the varistor powder mixture into a disc, sintering the pressed disc, followed by slow cooling to room temperature.The sintered disc is acid etched and a fritted-silver electrode applied on each side of the disc or in the alternative an aluminum coating is arc sprayed on each side of the disk followed by an arc sprayed copper coating on top of the aluminum coating. The fritted-silver electrode coating is heated to 660.degree. C. and slow cooled to room temperature. Sn-coated copper leads are soldered on the electroded disc of either electrode process and the assembly is encapsulated in resilient epoxy resin to form the encapsulated metal oxide varistor package.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.

Abstract: An arc limiting refractory resistive element is fabricated from aluminum oxide, carbon black and a sintering aid. The fabricating process includes compacting a mixture of the materials, sintering the compact in an inert atmosphere, then oxidizing the outer region of the sintered compact to form a non-conductive sheath around the electrically conductive material.

Abstract: A multi-stage process for reducing the content of sulfur-containing gases--notably hydrogen sulfide, sulfur dioxide, carbonyl sulfide and carbon disulfide--in waste gas streams is provided. In the first stage, the gas stream is passed through a reaction zone at a temperature between about 150.degree. and 350.degree. C. in the presence of a pretreated novel catalyst of the formulaxLn.sub.2 O.sub.3.yT.sub.2 O.sub.3in which Ln is yttrium or a rare earth element and T is cobalt, iron or nickel, and each of x and y is independently a number from 0 to 3, said catalyst being substantially non-crystalline and having a surface area of from about 10 m.sup.2 /g to about 40 m.sup.2 /g. The preferred catalyst is one in which Ln is lanthanum, T is cobalt, and x and y range from 1 to 3, including non-integers. The first stage yields a product stream having a reduced content of sulfur-containing gases, including specifically, substantial reduction of carbonyl sulfide and virtual elimination of carbon disulfide.

Abstract: A catalytic process for the reduction to elemental sulfur of the sulfur dioxide contained in gas streams using a reducing gas such as hydrogen, or preferably carbon monoxide, in a reactor charged with a material represented by the general formula M.sup.II M.sub.2.sup. III O.sub.4 crystallized in the spinel structure wherein M.sup.II is a divalent metal and M.sup.III is a trivalent metal from the first transition period of the Periodic Table of the Elements, or derivatives of the materials of the above formula resulting from pretreatment with hydrogen or, preferably carbon monoxide, and/or exposure to the sulfur dioxide-containing gas stream.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, in a reactor charged with a material represented by the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd.In a further aspect of this invention, a gas stream containing hydrogen sulfide or carbonyl sulfide and sulfur dioxide is passed through a reaction chamber charged with Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd, to catalytically produce at a sufficiently elevated temperature elemental sulfur with concomitant reduction of the concentrations of the undesired hydrogen sulfide or carbonyl sulfide and sulfur dioxide.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, and a catalyst of the formula Ln.sub.2 O.sub.3 . Co.sub.2 O.sub.3, where Ln is either Y or Gd.

Abstract: This application describes a process for the catalytic reduction of sulfur dioxide in gas streams containing sulfur dioxide to elemental sulfur using a reducing gas such as hydrogen or, preferably, carbon monoxide, and a catalyst of the formula xLa.sub.2 O.sub.3 . yCo.sub.2 O.sub.3, where x and y are varied independently from 1-3 (including non-integers). Novel catalyst compositions where x .noteq. y are also claimed.