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Microwave sintering of nanophase ceramics without concomitant grain growth (open access)

Microwave sintering of nanophase ceramics without concomitant grain growth

A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO[sub 2] as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.
Date: April 15, 1991
Creator: Eastman, J.A.; Sickafus, K.E. & Katz, J.D.
System: The UNT Digital Library
Synthesis of actinide nitrides, phosphides, sulfides and oxides (open access)

Synthesis of actinide nitrides, phosphides, sulfides and oxides

This invention is comprised of a process of preparing an actinide compound of the formula An{sub x}Z{sub y} wherein An is an actinide metal atom selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, x is selected from the group consisting of one, two or three, Z is a main group element atom selected from the group consisting of nitrogen, phosphorus, oxygen and sulfur and y is selected from the group consisting of one, two, three or four, by admixing an actinide organometallic precursor wherein said actinide is selected from the group consisting of thorium, uranium, plutonium, neptunium, and americium, a suitable solvent and a protic Lewis base selected from the group consisting of ammonia, phosphine, hydrogen sulfide and water, at temperatures and for time sufficient to form an intermediate actinide complex, heating said intermediate actinide complex at temperatures and for time sufficient to form the actinide compound, and a process of depositing a thin film of such an actinide compound, e.g., uranium mononitride, by subliming an actinide organometallic precursor, e.g., a uranium amide precursor, in the presence of an effective amount of a protic Lewis base, e.g., ammonia, within a reactor at temperatures and for time …
Date: April 2, 1991
Creator: Van Der Sluys, W. G.; Burns, C. J. & Smith, D. C.
System: The UNT Digital Library
Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams (open access)

Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams

Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.
Date: April 10, 1991
Creator: Hawryluk, A. M. & Ceglio, N. M.
System: The UNT Digital Library
Improved monolithic tandem solar cell (open access)

Improved monolithic tandem solar cell

A single-crystal, monolithic, tandem, photovoltaic solar cell is described which includes (a) an InP substrate having upper and lower surfaces, (b) a first photoactive subcell on the upper surf ace of the InP substrate, (c) a second photoactive subcell on the first subcell; and (d) an optically transparent prismatic cover layer over the second subcell. The first photoactive subcell is GaInAsP of defined composition. The second subcell is InP. The two subcells are lattice matched.
Date: April 23, 1991
Creator: Wanlass, M. W.
System: The UNT Digital Library
Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells (open access)

Chloromethyl chlorosulfate as a voltage delay inhibitor in lithium cells

Chloromethyl chlorosulfate (CMCS) is used as a passive film growth inhibitor in electrochemical cells to minimize voltage delay and low-voltage discharge. Film growth on lithium anodes is significantly diminished when CMCS is added to SOCl{sub 2} and SO{sub 2}Cl{sub 2} electrolytes of lithium batteries. The CMCS also has the effect of extending the shelf-life of Li/SOCl{sub 2} and Li/SO{sub 2}Cl{sub 2} batteries.
Date: April 5, 1991
Creator: Delnick, F. M.
System: The UNT Digital Library
Basic fluid system trainer (open access)

Basic fluid system trainer

This invention, a trainer mounted and housed within a mobile console, is used to teach and reinforce fluid principles to students. The system trainer has two centrifugal pumps, each driven by a corresponding two-speed electric motor. The motors are controlled by motor controllers for operating the pumps to circulate the fluid stored within a supply tank through a closed system. The pumps may be connected in series or in parallel. A number of valves are also included within the system to effect different flow paths for the fluid. In addition, temperature and pressure sensing instruments are installed throughout the closed system for measuring the characteristics of the fluid, as it passes through the different valves and pumps. These measurements are indicated on a front panel mounted to the console, as a teaching aid, to allow the students to observe the characteristics of the system.
Date: April 30, 1991
Creator: Semans, J. P.; Johnson, P. G.; LeBoeuf, R. F. Jr.; Kromka, J. A.; Goron, R. H. & Hay, G. D.
System: The UNT Digital Library
Laser cutting with chemical reaction assist (open access)

Laser cutting with chemical reaction assist

This invention is comprised of a method for cutting with a laser beam where an oxygen-hydrocarbon reaction is used to provide auxiliary energy to a metal workpiece to supplement the energy supplied by the laser. Oxygen is supplied to the laser focus point on the workpiece by a nozzle through which the laser beam also passes. A liquid hydrocarbon is supplied by coating the workpiece along the cutting path with the hydrocarbon prior to laser irradiation or by spraying a stream of hydrocarbon through a nozzle aimed at a point on the cutting path which is just ahead of the focus point during irradiation.
Date: April 8, 1991
Creator: Gettemy, D. J.
System: The UNT Digital Library
Microwave Sintering of Nanophase Ceramics Without Concomitant Grain Growth (open access)

Microwave Sintering of Nanophase Ceramics Without Concomitant Grain Growth

A method of sintering nanocrystalline material is disclosed wherein the nanocrystalline material is microwaved to heat the material to a temperature less than about 70% of the melting point of the nanocrystalline material expressed in degrees K. This method produces sintered nanocrystalline material having a density greater than about 95% of theoretical and an average grain size not more than about 3 times the average grain size of the nanocrystalline material before sintering. Rutile TiO{sub 2} as well as various other ceramics have been prepared. Grain growth of as little as 1.67 times has resulted with densities of about 90% of theoretical.
Date: April 15, 1991
Creator: Eastman, Jeffrey A.; Sickafus, Kurt E. & Katz, Joel D.
System: The UNT Digital Library
Cooler and particulate separator for an off-gas stack (open access)

Cooler and particulate separator for an off-gas stack

This report describes an off-gas stack for a melter, furnace or reaction vessel comprising an air conduit leading to two sets of holes, one set injecting air into the off-gas stack near the melter plenum and the second set injecting air downstream of the first set. The first set injects air at a compound angle, having both downward and tangential components, to create a reverse vortex flow, counter to the direction of flow of gas through the stack and also along the periphery of the stack interior surface. Air from the first set of holes prevents recirculation zones from forming and the attendant accumulation of particulate deposits on the wall of the stack and will also return to the plenum any particulate swept up in the gas entering the stack. The second set of holes injects air in the same direction as the gas in the stack to compensate for the pressure drop and to prevent the concentration of condensate in the stack. A set of sprayers, receiving water from a second conduit, is located downstream of the second set of holes and sprays water into the gas to further cool it.
Date: April 8, 1991
Creator: Wright, G. T.
System: The UNT Digital Library
Three-Axis Particle Impact Probe (open access)

Three-Axis Particle Impact Probe

Three-axis particle impact probes detect particle impact vectors along x-, y-, and z-axes by means of a head mounted on the outer end of a shaft that is flexibly mounted in silicone rubber at the top of a housing so as to enable motion imparted to the head upon impact to be transmitted to a grounded electrode secured to the shaft within the housing. Excitable electrodes are mounted in the housing in a fixed position, spaced apart from the ground electrode and forming, with the ground electrode, capacitor pairs. Movement of the ground electrode results in changes in capacitance, and these differences in capacitance are used for measurement or derivation of momentum vectors along each of the three axes. In one embodiment, the ground electrode is mounted at the base of the shaft and is secured to a silicone rubber layer at the top of the housing, providing for cantilevered movement. In another embodiment, the shaft is mounted at its mid point in a flexible bushing so that it undergoes pivotal movement around that point.
Date: April 2, 1991
Creator: Fasching, G. E.; Smith, Nelson S., Jr. & Utt, C. E.
System: The UNT Digital Library
Material containment enclosure (open access)

Material containment enclosure

An isolation enclosure and a group of isolation enclosures was designed which is useful when a relatively large containment area is required. The enclosure is in the form of a ring having a section removed so that a technician may enter the center area of the ring. in a preferred embodiment, an access zone is located in the transparent wall of the enclosure and extends around the inner perimeter of the ring so that a technician can insert his hands into the enclosure to reach any point within. The inventive enclosures provide more containment area per unit area of floor space than conventional material isolation enclosures.
Date: April 1, 1991
Creator: Carlson, D. O.
System: The UNT Digital Library
Electrochemical cell (open access)

Electrochemical cell

This invention is comprised of an electrochemical cell has a layer-type or sandwich configuration with a Teflon center section that houses working, reference and counter electrodes and defines a relatively narrow electrolyte cavity. The center section is surrounded on both sides with thin Teflon membranes. The membranes are pressed in place by a pair of Teflon inner frames which are in turn supported by a pair of outer metal frames. The pair of inner and outer frames are provided with corresponding, appropriately shaped slits that are in plane generally transverse to the plane of the working electrode and permit X-ray beams to enter and exit the cell through the Teflon membranes that cover the slits so that the interface between the working electrode and the electrolyte within the cell may be analyzed by transmission geometry. In one embodiment, the center section consists of two parts, one on top of the other. Alternatively, the center section of the electrochemical cell may consist of two intersliding pieces or may be made of a single piece of Teflon sheet material. The electrolyte cavity is shaped so that the electrochemical cell can be rotated 900 in either direction while maintaining the working-and counter electrodes …
Date: April 23, 1991
Creator: Nagy, Z.; Yonco, R. M.; You, Hoydoo & Melendres, C. A.
System: The UNT Digital Library
Manufacture of silicon carbide using solar energy (open access)

Manufacture of silicon carbide using solar energy

This invention is comprised of a method is described for producing silicon carbide particles using solar energy. The method is efficient and avoids the need for use of electrical energy to heat the reactants. Finely divided silica and carbon are admixed and placed in a solar-heated reaction chamber for a time sufficient to cause a reaction between the ingredients to form silicon carbide of very small particle size. No grinding of silicon carbide is required to obtain small particles. The method may be carried out as a batch process or as a continuous process.
Date: April 8, 1991
Creator: Glatzmaier, G. C.
System: The UNT Digital Library
Reversibly immobilized biological materials in monolayer films on electrodes (open access)

Reversibly immobilized biological materials in monolayer films on electrodes

A method is provided for reversibly binding charged biological particles in a fluid medium to an electrode surface. The method comprises treating (e.g., derivatizing) the electrode surface with an electrochemically active material; connecting the electrode to an electrical potential; and exposing the fluid medium to the electrode surface in a manner such that the charged particles become adsorbed on the electrode surface.
Date: April 8, 1991
Creator: Weaver, P. F. & Frank, A. J.
System: The UNT Digital Library