Abstract: An improved dental composition comprises a uniform admixture in specified proportions of two powdered alloys of specified structure and composition, which when amalgamated with mercury produces a corrosion-resistant dental amalgam having enhanced mechanical properties and handling characteristics.

Abstract: Dental compositions comprising an admixture of two powdered alloys which when amalgamated with mercury produce corrosion-resistant dental amalgams.

Abstract: A novel dental composition comprises an admixture of two forms of a powdered alloy in specified proportions, i.e., a major proportion in the form of relatively smooth spheroidal particles, e.g., spheres, and a minor proportion in the form of relatively rough, irregularly shaped particles, e.g., flakes. The resulting dental composition requires less mercury for amalgamation and exhibits enhanced physical properties and handling characteristics.

Abstract: An improved dental composition comprises an admixture in specified proportions of two powdered alloys of specified composition, one in the form of spheres, the other in the form of irregularly-shaped particles such as flakes. When the admixture is amalgamated with mercury, a corrosion-resistant dental amalgam having enhanced mechanical properties and handling characteristics is produced.

Abstract: There is disclosed a process for isomerizing alkylated benzenes having from 3-10 carbon atoms and methyl or ethyl alkyl substituents. The reaction is conducted in the presence of molecular hydrogen and a catalyst having a platinum group metal, especially platinum, and rhenium promoters on a porous, solid oxide, acidic support. The support can be a mixture of a low acidic material such as alumina, and a higher acidic material such as silica-alumina or crystalline aluminosilicate. The catalyst promoters are preferably supported on the low acidity base component.

Abstract: Prior to the bonding of precious metal ribbon to flat base metal strips useful for the fabricating of electrical contacts, grooves are skived into the surface of the metal strip to receive the precious metal ribbon. The apparatus disclosed is capable of skiving grooves of a predetermined depth in a flat metal strip, thereby avoiding the wastage of precious metal ribbon which occurs when such grooves are cut too shallowly or too deeply. In a preferred embodiments, an indexing wheel follows the surface of the metal strip and cutters adjusted to maintain a fixed spaced relation to the indexing wheel skive grooves of predetermined constant depth.In another embodiment, a method of installing precious metal ribbon within grooves skived into metal strips is disclosed which comprises controlling the depth of such grooves by use of the principles and apparatus of the invention.

Abstract: A reduced charge montmorillonite pigment useful as a colorformer in record material, especially pressure-sensitive carbonless copying record systems. The pigment is produced by replacing exchangeable cations of a selected dioctahedral montmorillonite crude clay (exemplified by certain bentonite clays) with a predetermined amount of lithium ions, mildly heating the lithium-exchanged montmorillonite to collapse irreversibly the montmorillonite structure, and grinding the heat-treated material to pigment-size particles, the grinding preferably being carried out in a fluid energy mill. When the pigment particles are coated on paper, the coated sheets produce stabilized intense images when printed with a solution of crystal violet lactone (CVL) dye precursor and thus may be used in record material with CVL without employing secondary slow acting dyes such as benzoyl leuco methylene blue. The sheets are also useful with other colorless or substantially colorless dye precursors.

Abstract: Catalysts suitable for promoting selected oxidation and reduction reactions; especially for eliminating or substantially reducing pollutants in waste gas streams such as automobile exhaust, or nitric acid plant tail gas, are described, as are processes for their preparation and use. The catalysts contain platinum group metal, rare earth metal and alumina components which may be supported on relatively catalytically inert carriers, for instance, honeycombs. The catalysts can be prepared, for example, by pre-calcining a mixture of alumina and rare earth metal oxide, e.g., ceria, at a temperature of at least about 750.degree. C. to obtain a catalytically-active material; coating a relatively inert support, if such is used, with an aqueous slurry of the calcined material; calcining the composite, adding platinum group metal thereto and drying.

Abstract: Carbonaceous fuel is thermally combusted with an amount of air substantially less than that needed for complete combustion to carbon dioxide and water of all the combustible components in the fuel to produce a gaseous first effluent containing a substantial proportion of carbon monoxide but little or no nitrogen oxides. The first effluent is mixed with additional air and at least a portion of the resulting mixture is passed into the presence of a solid oxidation catalyst for combustion at a temperature above the instantaneous auto-ignition temperature of the mixture but below nitrogen-oxide-forming temperatures. Heat is withdrawn from the initial thermal combustion stage and from the gases downstream of the catalyst for the purpose for which the furnace is being operated.

Abstract: A method and apparatus for operating a gas turbine system are disclosed utilizing an adiabatic combustion process, employing combustion of a pre-mixed carbonaceous fuel-air admixture in a combustion zone. The combustion and the combustion zone are maintained at an approximately constant temperature by selective control of the fuel-to-air ratio over a period of turbine operation during which the fuel demand or the combustion air temperature varies. Such combustion is conducted in the presence of an oxidation catalyst and the combustion zone including the catalyst is maintained at an approximately constant temperature. In a mode of operation which is preferred when conditions permit, such temperature is substantially above the instantaneous auto-ignition temperature of the fuel-air admixture but below a temperature that would result in any substantial formation of oxides of nitrogen.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina, a rare earth metal oxide, and a mixture of metallic oxides of selected IIA and IVA metals and selected VIB metals. The slips or carrier compositions are calcined at a temperature of at least 500.degree.C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 /g after calcination at a temperature of 1200.degree.C. for two hours.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina, selected VIB metal oxides, and a metallic oxide or oxide mixture wherein the metal or metals are selected IIA, IVA, and IIA-IVA mixtures, selected IIA and IVB mixtures and selected IVA and IVB mixtures. The slips or carrier compositions are calcined at a temperature of at least 500.degree.C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 g after calcination at a temperature of 1200.degree.C. for two hours.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina, a rare earth metal oxide, and a metallic oxide wherein the metal is IVB, selected VIB metals, and mixtures thereof. The slips or carrier compositions are calcined at a temperature of at least 850.degree.C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 /g after calcination at a temperature of 1200.degree.C. for two hours.

Abstract: An insolubilized mineral-supported enzyme composite having outstanding catalytic activity and mechanical stability comprises an enzyme covalently attached to silanized porous, attrition-resistant granules of heat-activated attapulgite clay.

Abstract: Thick film resistive elements are prepared from an intimate admixture comprising silica, lead oxide and ruthenium dioxide or iridium dioxide which is heated to a temperature sufficient to provide a lead-containing glass having dispersed therein lead ruthenate or lead iridate. The lead-containing glass is comminuted and a resistor paste is formed which can be subsequently coated and fired on to a desired substrate to form the thick film resistive component. The method of this invention may facilitate the production of thick film resistors exhibiting a low temperature coefficient of resistivity, relative freedom from noise and drift, and high moisture resistance.

Abstract: A catalytic gas treatment apparatus in which a unitary catalytic element, having gas flow paths therethrough, is positioned within a surrounding casing. At least one, and preferably two, end flanges are provided and are positioned in a direction inwardly with respect to the casing and are adjacent the catalytic element end faces. Expansible and/or resilient retention members are positioned between the end flanges and the catalytic element end faces to expand as differences in thermal expansion rates result in differences in the distance between the end flanges and the catalytic element end faces. Consequently, untreated gas cannot pass between the catalytic element outer surface and the casing inner surface, and damage of the catalytic element end faces by the end flanges is lessened during vibration of the apparatus while operating at a high temperature.

Abstract: Catalysts having good high temperature stability which are particularly useful for selected high temperature reactions are disclosed as are methods for their preparation and use. The catalytically-active materials include platinum group metal deposited on a catalytic slip or composite which contains a mixture of alumina and a mixture of IVB and selected VIB metal oxides. The slips or carrier compositions are calcined at a temperature of at least 850.degree.C. before deposition of platinum group metal and characterized by having a surface area of at least 20 m.sup.2 /g after calcination at a temperature of 1200.degree.C. for two hours.

Abstract: Pollution control apparatus is provided for use in scrubbing a gas, which is normally vented to the atmosphere, with a liquid, which apparatus embodies in one unit a section to remove solid particulates and entrained liquid from the gas, as well as a packed tower scrubbing section for removing noxious gaseous components from the gas. The apparatus is comprised of an outer shell; and an inner shell disposed within and spaced from the outer shell, the inner shell defining an inner contact zone and the space between the inner shell and the outer shell defining an outer contact zone; liquid feed means for introducing liquid into the inner contact zone; gas feed means for introducing a gas into contact with the liquid in the inner contact zone and for introducing the gas into the outer contact zone; outlet means for liquid; and outlet means for processed gas. The inner contact zone preferably includes a packing material.

Abstract: Disclosed is a method for subjecting a finely divided solid to a series of processing steps on a single horizontal vacuum belt filter wherein the processing includes a liquid-solid mass transfer function, such as ion-exchange, carried out by percolation, and this step is followed by at least one step, such as washing, in which rapid passage of a large volume of liquid through the solid takes place. The method is used to ion-exchange zeolitic microspheres in the production of a fluid cracking catalyst.

Abstract: A thermocouple structure useful for high temperature applications comprises a pair of thermocouple wires joined at one end to form a thermocouple, the wires being enclosed within a metallic sheath which is open at one end. The thermocouple and the wires within the sheath are surrounded and insulated by crushed compacted magnesium oxide. The end of the sheath from which the thermocouple wires extend is filled with ceramic cement to seal the crushed magnesium oxide and the wires therein. The thermocouple structure is prepared by inserting stripped thermocouple wires into a cylindrical two-hole perforated magnesium oxide preform and the resulting assembly placed within a metal sheath. The resulting assembly is then swaged or reduced in diameter to crush and compact the magnesium oxide therein. The resulting swaged assembly is opened, if desired, to expose the ends of the wires which are then welded to form a thermocouple.