Abstract: A composition for production of silica glass using a sol-gel process is described, comprising silica particles, a dispersing agent, and a solution containing a polymerizable monomer for formation of acrylic resin and a crosslink agent dissolved in distilled water. The polymerizable monomer is n-methylol acrylamide or n-methylol methacrylamide. A method for production of silica glass is described, including the step of adding silica particles and a dispersing agent to a premix solution of the polymerizable monomer for formation of acrylic resin and the crosslink agent dissolved in distilled water.

Abstract: This invention describes a method of rapidly monitoring the temperature of a medium and a method of preparing a quantum confined device that can enable such measurements. The monitoring principle uses changes in impedance of nanostructured devices, i.e. devices in which one or more materials have the domain size precision engineered to less than 500 nanometers, preferably to dimensions less than the domain sizes where quantum confinement effects become significant and modify the electrical or thermal properties of the materials. The invention can be used to monitor absolute values of and changes in temperature of gases, inorganic and organic liquids, solids, suspensions, and mixtures of one or more of the said phases. The invention can be used to monitor radiation, power, heat and mass flow, charge and momentum flow, and phase transformation.

Abstract: A sol-gel process for producing dry porous gel monoliths, e.g., silica glass monoliths, in which the successive process steps of gelling, aging and drying all occur within a mold formed of a selected porous material, e.g., graphite. The mold is inert to the gel solution and it has sufficient strength to withstand the temperatures and pressures encountered during the process. The mold and gel thereby can remain within a sealed autoclave during these process steps, and mechanical handling of the mold and the gel are minimized. This substantially enhances the process' efficiency. Alternatively, the mold can have a non-porous inner skin to enhance ease of cleaning of the mold, and of removal of the gel.

Abstract: Ceramic sintered bodies having a different thickness along a predetermined axial direction are manufactured in the following manner. At first, a ceramic formed body to be sintered having different thickness along the predetermined axial direction is accommodated in a hot press apparatus. An upper forming mold and a lower forming mold each having a forming surface corresponding to an upper surface and a lower surface of the ceramic formed body to be sintered are set. A pressure along the predetermined axial direction is applied to the ceramic formed body to be sintered via the upper forming mold and the lower forming mold while heating the ceramic formed body to be sintered to perform a hot press sintering thereof. A thickness of a ceramic sintered body is controlled in such a manner that a maximum thickness in the predetermined direction is not more than two times a minimum thickness in the predetermined direction.

Abstract: A method for quartz crucible formation wherein an at least substantially enclosed chamber surrounds a crucible mold. The atmosphere in the chamber is controlled to include a desired gas or combination of gases at a positive pressure. The positive pressure is achieved because the total outflow of gas is less than the total inflow of gas. A heat source is initiated to melt a quartz material lining the mold once the desired atmosphere is achieved, and the quartz material is fused.

Abstract: The present invention relates to an optical fiber fabrication method by which an optical fiber having an objective chromatic dispersion characteristic can be obtained readily. In an optical fiber fabrication method, a cutoff wavelength is measured in an optical fiber with a fixed length obtained by first drawing a part of an optical fiber preform. A target glass diameter for yielding an objective chromatic dispersion characteristic is then determined based on the cutoff wavelength thus measured. Then the rest of the optical fiber preform is drawn so that the glass diameter becomes the target glass diameter thus determined, thereby fabricating the optical fiber.

Abstract: A mold for molding a core for use in casting hollow parts includes, a lower mold portion and an upper mold portion defining therein a cavity corresponding to the outer surface of the core. The lower mold portion includes a cutout disposed along a parting line defined between the lower mold portion and the upper mold portion and opening onto the cavity. After introduction of a ceramic slurry mixture into the mold the upper mold portion is removable, to expose a first side of the core and a protective flash formed in the cutout. Desirably, a heat shield is positioned over the protective flash and the exposed portion of the parting line of the lower mold portion so that the lower mold portion is not exposed directly to a flame during a preliminary firing to impart sufficient strength to the ceramic core so that the ceramic core may be handled.

Abstract: A method for producing shaped articles of ceramic composites provides a high degree of dimensional tolerance to these articles. A fiber preform is disposed on a surface of a stable formed support, a surface of which is formed with a plurality of indentations, such as grooves, slots, or channels. Precursors of ceramic matrix materials are provided to the fiber preform to infiltrate from both sides of the fiber preform. The infiltration is conducted under vacuum at a temperature not much greater than a melting point of the precursors. The melt-infiltrated composite article substantially retains its dimension and shape throughout the fabrication process.

Abstract: A device and process for forming hollow glassware comprising producing solid glass blanks in a manufacturing line, storing the blanks, feeding the blanks to a manufacturing line for forming hollow glassware, preheating the blanks during the feeding step, supplying the preheated blanks to a heating stage, heating to form solid plastically deformable glass globs, transferring the glass gobs to a blow molding stage and blow molding the glass gobs supported by a bottom lifter in a blow mold.

Abstract: Disclosed is a method for producing an SiC preform of a high volume fraction used for the manufacture of a metal matrix composite. The method involves the steps of mixing SiC particles of different particle sizes each selected from a range of 0.2 to 48 &mgr;m with an organic binder, an inorganic binder, an aggregating agent, and distilled water, thereby producing a mixture, and stirring the mixture in accordance with a ball milling process, thereby producing a slurry containing the SiC particles, pouring the slurry containing the SiC particles into a mold having upper and lower molds respectively provided with absorbent bodies, and squeezing the slurry in the mold, thereby reducing a residual moisture content of the slurry, completely drying the slurry reduced in residual moisture content, thereby producing an SiC preform, and calcinating the SiC preform. The preform is impregnated with a metal matrix while maintaining a high reinforcement volume fraction of 70 vol % or more.

Abstract: A method for manufacturing a discharge tube, including heating a quartz tube by irradiation and closing it shut, is presented, in which variation of the heating temperature of the quartz tube can be reduced. Laser light is irradiated on a portion of the quartz tube, and in the step of sealing the portion of the quartz tube onto which laser light has been irradiated, the laser light is scanned while oscillating back and forth. The intensity of the laser light is controlled such that the intensity of the laser light when the size of a displacement of the laser light is maximal is smaller than the intensity of the laser light when the size of the displacement of the laser light is minimal.

Abstract: A health support device having a lamination of a semiconductor film on a surface of a partially-reduced sintered material of titanium oxide. The semiconductor film is preferably a p-type semiconductor film of silicon or germanium. The partially-reduced sintered material is preferably represented by TiO2−x, where 0<×<0.5. The thickness of the semiconductor film is preferably from 1 nm to 500 nm. In production, a mixture of a titanium oxide powder and a binder is press-molded, and the molded material is sintered at a temperature of from 500° C. to 1100° C. in a vacuum, inert or reducing atmosphere. A p-type semiconductor film is formed on a surface of the resulting partially-reduced sintered material of titanium oxide.

Abstract: This invention relates to production of high purity fused silica glass doped with titania using titanium chelates. Useful chelates include titanium acetylacetonate, and titanium ethyl acetoacetate among others.

Abstract: A method for welding a dummy tube to a quartz glass tube for use as an optical fiber preform, comprising chamfering the inner edge portion of the dummy tube and/or the quartz glass tube for use as the optical fiber preform before welding the quartz glass tube for use as the optical fiber preform with the dummy tube, and then melt welding them together.

Abstract: A method of manufacturing a dielectric ceramic composition comprising at least a main component of BaTiO3, a second subcomponent as represented by (Ba, Ca)xSiO2+x (where, x=0.8 to 1.2), and other subcomponents. The main component and at least part of the subcomponents except the second subcomponent are mixed to prepare a pre-calcination powder and the pre-calcination powder is calcined to prepare a calcined powder. The second subcomponent is at least mixed in the calcined powder to obtain a dielectric ceramic composition having a ratio of each subcomponent to the main component of BaTiO3 of a predetermined molar ratio.

Abstract: The present invention relates to a process for preparing silica-alumina carriers preferably under the form of extrudates. Further, the present invention also provides hydrogenation catalysts prepared thereof. These catalysts are used in an improved process for the reduction of the aromatic hydrocarbons content present in hydrocarbon streams.

Abstract: Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.

Abstract: The invention relates to a device for drawing optical fibers from a preform, comprising: a furnace comprising a tube for heating one end of said preform to the drawing temperature thereof, which tube comprises: i) a central tube, ii) an upper extension tube connected to the lower part of said central tube so as to obtain a gas tight seal against an ambient atmosphere exterior said furnace, wherein the upper extension tube comprises an inlet for an inert gas in the top region of the upper extension tube, as a result of which the preform and the fiber to be drawn therefrom are surrounded by an inert gas, iii) a lower extension tube connected to said upper extension tube in such a manner that a gas tight seal against an ambient atmosphere exterior said furnace is obtained, iv) a tube outlet connected to said lower extension tube, means for drawing the fiber, means for supporting the preform in the furnace.

Abstract: A continuous process for the manufacture of a ceramic sintered compact wherein the process comprises the steps of: forming a green compact from a powder mixture comprising a first component comprising compounds which contain elements of silicon, aluminum, oxygen and nitrogen; and the powder mixture further comprising a second component comprising a compound of at least one element selected from the group consisting of yttrium, scandium, cerium, lanthanum and the metals of the lanthanide series, and the second component comprising between 0.1 and 10 weight percent of the powder mixture; heat treating the green compact wherein the heat treatment comprises continuously passing the green compact through at least one heating zone so as to produce a sintered compact.

Abstract: A method of making spherical bodies from powder, which comprises (1) preparing an adjusted powder so as to have at least one powder characteristic selected from the group consisting of an average particle size, a powder particle size distribution and a BET specific surface area, (2) preparing nuclei having a particle size larger than that of the adjusted powder, (3) rotating the nuclei, and (4) adding the adjusted powder and a solvent to the rotating nuclei so that particles of the adjusted powder accumulate on the nuclei to form granular bodies. Also disclosed is a spherical body having a core or nucleus formed in the spherical body, an adjusted powder composition for forming a spherical body, and a method for manufacturing spherical sintered bodies of silicon nitride.