Abstract: An optical glass article having a desired surface figure and demonstrating maximum theoretical light transmission can be prepared by forming a base anhydrous glass of defined compositional ranges, hydrating the glass, partially dehydrating the glass at a temperature above the softening point and, using an inert gas, at a pressure above the vapor pressure of water contained therein, and then molding a preformed blank of the glass against a die having a desired optical quality surface figure, the molding being under conditions sufficient to transfer the surface figure of the die to the glass. The base glass comprises, in mole percent, about 70 to 82% SiO.sub.2, 10 to 17% Na.sub.2 O and/or K.sub.2 O, and 5 to 15% of an oxide or oxides selected from ZnO and PbO. The water content of the partially dehydrated glass ranges from about 3 to 8 wt. percent and the molded glass has a substantially uniform refractive index throughout its bulk.

Abstract: A silver-halide photochromic glass of alkali-boroaluminosilicate base composition, having a brown coloration in the faded and darkened state, is provided by treating a potentially photochromic glass of specified composition according to a defined two-phase heat treatment to develop photochromic properties therein.

Abstract: Method and apparatus for staining biological specimens by forming a film of staining reagents on the surface of the specimen containing slide. Heating means raises the temperature of the staining reagents on the slide. The temperature of the reagent film is determined, and a feedback signal to the heating means accurately maintains the temperature of the film within a predetermined range.

Abstract: The instant invention is concerned with a unique method for crystallizing glass bodies into glass-ceramic articles. More particularly, this invention is drawn to a method whereby glass-ceramic articles can be formed without cooling the precursor glass below the transformation range thereof. Thus, the glass melt is cooled and formed into a vitreous body. This vitreous body is cooled to a temperature no lower than about 25.degree.-250.degree. C. above the transformation range where nucleation is developed therewithin. Essentially immediately thereafter, the nucleated body is exposed to a temperature between about 100.degree.-500.degree. C. higher than that of the nucleation step to cause the growth of crystals on the nuclei. The process significantly expedites the production of glass-ceramic articles and substantially reduces energy consumption from the forming stage to the finished product.

Abstract: An improved method of modifying a honeycombed body having a multiplicity of open-ended cells extending therethrough between opposite face ends of the body to produce therein a multiplicity of flow paths for at least two and possibly three separate fluids. For accommodating two fluids, selected columns of cells within the honeycombed body are provided with openings near at least one face end for first fluid flow through one or two longitudinal, opposed boundary surfaces and through inner cell walls parallel to the cell axes while the open-ends of such columns on a face end perpendicular to the selected cell axes are sealed against fluid flow. Second fluid flow is through the unselected columns of cells parallel to and either in the direction of or counter to the first fluid flow. Specifically, the invention provides an improved method for sealing the selected columns of cells on face ends of the body.

Abstract: A plurality of individual pre-shaped cores or pins are initially positioned in a prearranged orientation upon an outlet surface of a die body by means of a plate of photosensitive glass or glass-ceramic material which has been etched to form a mask with the desired pattern or arrangement of openings for orienting said cores or pins upon said die surface for subsequent securement thereto such as by welding.

Abstract: Fused oxide type glasses produced by flame hydrolysis are described. These glasses are composed of P.sub.2 O.sub.5 and, optionally, SiO.sub.2. P.sub.2 O.sub.5 is present in an amount of at least 2% by weight.

Abstract: A heat exchange element, particularly suitable for use as a recuperator for external combustion engines, or a body for use as an afterburner or in filtration and osmosis, may be produced as a monolithic, ceramic, honeycombed body having a plurality of flow paths therethrough for two or three fluids wherein multiple flow paths of separate fluids are separated by walls which may be less than 10 mils thick.In a preferred method, a honeycombed ceramic body is provided with a plurality of open-ended cells extending from one face end to another face end and arranged in vertical columns of cells separated by vertical fluid barrier wall surfaces. Selected columns of open-ended cells are closed on both face ends of the body and entrance to and exit from the selected cells is provided by removing portions of cell walls near face ends of the body between fluid barrier wall surfaces.

Abstract: A honeycomb structure is formed with a plurality of interconnected partitions which are unidirectionally discontinuous in a plane transverse to the longitudinal axis of the structure and which form a plurality of diamond-shaped cellular open portions extending longitudinally through the structure, to thereby provide a honeycomb structure with a relatively low bulk modulus and substantially isotropic moduli in transverse planes perpendicular to the longitudinal axis of the honeycomb structure, thus providing improved thermal shock resistance.

Abstract: This invention relates to the production of glass-ceramic articles in the Li.sub.2 O--MgO--Al.sub.2 O.sub.3 --SiO.sub.2 system nucleated with TiO.sub.2, and, optionally, ZrO.sub.2 which, containing beta-spodumene solid solution as the predominant crystal phase, exhibit average coefficients of thermal expansion over the range of 25.degree.-1000.degree. C. of less than about 15 .times. 10.sup.-.sup.7 /.degree. C. and total elongations after 2000 hours at 950.degree. C. of less than about 1000 PPM. The compositions are especially useful in the manufacture of honeycomb structures which are to be subjected to extreme changes in temperature, such as are experienced in regenerative heat exchangers for use in turbine engines.

Abstract: A method of densifying a fumed metal oxide is disclosed wherein the metal oxide is converted to a flowable sol and then dried to form a fragmented solid which is calcined. The calcined oxide may be wet milled to provide a slip for casting articles such as fused silica crucibles used in melting silicon.

Abstract: The present invention relates to a method of producing a borosilicate glass exhibiting a low coefficient of thermal expansion, viz., less than about 20 .times. 10.sup..sup.-7 /.degree. C. over the range of room temperature to 300.degree. C., an ability to withstand repeated thermal cycling between room temperature and temperatures up to 1300.degree. C. and higher without devitrification, and the ability to flow, when present in particulate form, at temperatures between about 1000.degree.-1250.degree. C. The method contemplates impregnating a porous, essentially alkali metal-free, high silica material with a solution or a molten mass of a B.sub.2 O.sub.3 -containing compound, the B.sub.2 O.sub.3 -containing compound also being essentially free from alkali metals. The impregnated glass is thereafter dried to eliminate any solvent. High emissivity can be imparted by incorporating minor amounts of such materials as CoO, NiO, MoO.sub.3, Fe.sub.2 O.sub.3, and V.sub.2 O.sub.5 as dopants during the impregnation step.

Abstract: A microbial growth medium for distinguishing Neisseria gonorrhoeae from Neisseria meningitidis. The medium comprises a gonococci and meningococci specific medium having incorporated therein a quantity of 8-anilino-1-naphthalene-sulfonic acid (ANS) or a salt thereof, at a concentration sufficient to permit the growth of the meningococci and inhibit the growth of the gonococci.

Abstract: A guide roller assembly rapidly adjustable to accommodate, at different times, lengths of different widths of tape, ribbon or similar material so as to maintain the centers of the widths of such lengths in alignment with a centerline extending about the periphery of the roller of said assembly midway between the ends thereof and during longitudinal movement of each said length over part of the periphery of the roller.

Abstract: This invention relates to the production of a composite article consisting of an opal glass body exhibiting a dense, milky-white appearance coated with an adherent enamel demonstrating high gloss and exceptional chemical durability. More specifically, the opal glasses of the present invention have compositions within the Na.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 -F system and demonstrate a softening point in excess of 760.degree. C., a strain point in excess of 490.degree. C., and a coefficient of thermal expansion (0.degree.-300.degree. C.) of about 66-75 .times. 10.sup..sup.-7 /.degree. C. The enamels of the instant invention have flux compositions within the Li.sub.2 O-B.sub.2 O.sub.3 -TiO.sub.2 -ZrO.sub.2 -PbO-SiO.sub.2 system, will fire to a high gloss in less than about 10 minutes at temperatures below about 720.degree. C., will exhibit coefficients of thermal expansion (25.degree.-300.degree. C.

Abstract: A method of forming a thin film capacitor having a tantalum oxide dielectric is described. A dielectric substrate having a non-tantalum electrically conductive film electrode formed thereon is disposed within an oxygen-nitrogen-inert gas containing vacuum environment. A film of tantalum oxide is applied over the conductive film by r-f sputtering of a tantalum oxide target within said vacuum environment while the dielectric substrate and conductive film are being cooled. The composite may then be removed from the oxygen-nitrogen-inert gas vacuum environment and a second electrically conductive film electrode applied over the so-formed tantalum oxide film.

Abstract: An optical waveguide cable is disclosed wherein a bundle of waveguide fibers is formed from a plurality of individual fibers coated with a release agent. The fiber bundle is encapsulated within an encapsulating material in which at least two strength members are embedded. The strength members are disposed parallel to the bundle in a plane substantially through the longitudinal axis of the bundle, at least one of the strength members being disposed in the plane on one side of the bundle while the remaining strength members are disposed in the plane on the other side of the bundle. Each of the waveguide fibers may be coated with a protective layer of a synthetic resinous material applied over the release agent before the bundle is formed.

Abstract: Mature zirconia ceramic compositions stabilized in the monoclinic and tetragonal structure with 0.1-5% ZnO and as little as 0.5% of a primary stabilizer selected from MgO, Y.sub.2 O.sub.3 or combinations thereof. Compacted ceramic compositions are fired and matured at temperatures below the volatilization point of ZnO and in the range of 2750.degree.-2950.degree. F.Zirconia is conventionally batched with magnesia, yttria or mixtures thereof, with or without other known stabilizers including ceria and calcia, together with up to about 5% ZnO and then compacted and sintered at a temperature which retains at least 0.1% ZnO in the fired body. Conventional cooling is prescribed. Subsequent thermal cycling of the fired body between 400.degree. and 2500.degree. F. reveals a stable body with no degradation in strength. Magnesia stabilized compositions show no signs of early destabilization on thermal cycling and may even show increasing room temperature strength as cycling progresses.

Abstract: Fused abrasive grain consists essentially of: (1) crystalline phases of corundum and zirconia, with an average crystallite size smaller than 300 microns and at least in part being an eutectic matrix and (2) analytically by weight, about 44 to 91% (preferably 44 to 80%) Al.sub.2 O.sub.3, about 5 to 50% (preferably 17.6 to 50%) ZrO.sub.2 to 0.1 to 12% (preferably 0.2 to 5%) R.sub.2 O.sub.3 wherein R is at least one metal selected from vanadium, chromium, manganese and cobalt, the percentage of R.sub.2 O.sub.3 is based on all R metal content calculated as R.sub.2 O.sub.3, and the balance, if any, being incidental impurities not exceeding 2%. The R metal content is present as oxide in solid solution within the corundum, as random particles of aluminate phase and/or as small particles of the R metal scattered throughout the grain, depending upon the relative oxidizing-reducing ambient conditions during melting.

Abstract: In a process for producing aluminous keatite ceramics by the hydrogen-for-lithium ion-exchange treatment of non-porous glass-ceramics, the efficiency of the lithium extraction step is substantially improved if beta-spodumene glass-ceramics having an Al.sub.2 O.sub.3 :modifying oxide ratio not exceeding about 1:1 are selected as starting materials.