36 Matching Results

Search Results

Low Loss Composition of BA{sub X}SR{sub Y}CA{sub 1-X-Y}TIO{sub 3}:BA{sub 0.12-0.25}SR{sub 0.35-0.47}CA{sub 0.32-0.53}TIO{sub 3}

Description: A dielectric thin-film material for microwave applications, including use as a capacitor, the thin-film comprising a composition of barium strontium calcium and titanium of perovskite type (Ba{sub x}Sr{sub y}Ca{sub 1-x-y})TiO{sub 3}. Also provided is a method for making a dielectric thin film of that formula over a wide compositional range through a single deposition process.
Date: October 19, 1999
Creator: Xiang, Xiao-Dong; Chang, Hauyee & Takeuchi, Ichiro
Partner: UNT Libraries Government Documents Department

A method to remove Ammonia using a Proton-Conducting Ceramic Membrane

Description: An apparatus and method for decomposing NH{sub 3}. A fluid containing NH{sub 3} is passed in contact with a tubular membrane that is a homogeneous mixture of a ceramic and a first metal, with the ceramic being selected from one or more of a cerate having the formula of M' Ce{sub 1-x} M''O{sub 3-{delta}}, zirconates having the formula M'Zr{sub 1-x} M''3-{delta}, stannates having the formula M'Sn{sub 1-x}M''O{sub 3}-{delta}, where M' is a group IIA metal, M'' is a dopant metal of one or more of Ca, Y, Yb, In, Nd, Gd or mixtures thereof and {delta} is a variable depending on the concentration of dopant and is in the range of from 0.001 to 0.5, the first metal is a group VIII or group IB element selected from the group consisting of Pt, Ag, Pd, Fe, Co, Cr, Mn, V, Ni, Au, Cu, Rh, Ru and mixtures thereof. The tubular membrane has a catalytic metal on the side thereof in contact with the fluid containing NH{sub 3} which is effective to cause NH{sub 3} to decompose to N{sub 2} and H{sub 2}. When the H{sub 2} contacts the membrane, H{sup +} ions are formed which pass through the membrane driving the NH{sub 3} decomposition toward completion.
Date: September 22, 1999
Creator: Balachandran, Uthamalingam & Bose, Arun C.
Partner: UNT Libraries Government Documents Department

Abrasion Resistant Coating and Method of making the same

Description: An abrasion resistant coating is created by adding a ductile phase to a brittle matrix phase during spray coating where an Al-Cu-Fe quasicrystalline phase (brittle matrix) and an FeAl intermetallic (ductile phase) are combined. This composite coating produces a coating mostly of quasicrystal phase and an inter-splat layer of the FeAl phase to help reduce porosity and cracking within the coating. Coatings are prepared by plasma spraying unblended and blended quasicrystal and intermetallic powders. The blended powders contain 1, 5, 10 and 20 volume percent of the intermetallic powders. The unblended powders are either 100 volume percent quasicrystalline or 100 volume percent intermetallic; these unblended powders were studied for comparison to the others. Sufficient ductile phase should be added to the brittle matrix to transform abrasive wear mode from brittle fracture to plastic deformation, while at the same time the hardness of the composite should not be reduced below that of the original brittle phase material.
Date: June 25, 1999
Creator: Sordelet, Daniel J. & Besser, Matthew F.
Partner: UNT Libraries Government Documents Department

Uniform bulk Material Processing using Multimode Microwave Radiation

Description: An apparatus for generating uniform heating in material contained in a cylindrical vessel is described. TE{sub 10}-mode microwave radiation is coupled into a cylindrical microwave transition such that microwave radiation having TE{sub 11}-, TE{sub 01}- and TM{sub 01}-cylindrical modes is excited therein. By adjusting the intensities of these modes, substantially uniform heating of materials contained in a cylindrical drum which is coupled to the microwave transition through a rotatable choke can be achieved. The use of a poor microwave absorbing insulating cylindrical insert, such as aluminum oxide, for separating the material in the container from the container walls and for providing a volume through which air is circulated is expected to maintain the container walls at room temperature. The use of layer of highly microwave absorbing material, such as SiC, inside of the insulating insert and facing the material to be heated is calculated to improve the heating pattern of the present apparatus.
Date: June 18, 1999
Creator: Varma, Ravi & Vaughan, Worth E.
Partner: UNT Libraries Government Documents Department

Method of Dehalogenation using Diamonds

Description: A method for preparing olefins and halogenated olefins is provided comprising contacting halogenated compounds with diamonds for a sufficient time and at a sufficient temperature to convert the halogenated compounds to olefins and halogenated olefins via elimination reactions.
Date: February 26, 1999
Creator: Farcasiu, Malvina; Kaufman, Phillip B.; Ladner, Edward P. & Anderson, Richard R.
Partner: UNT Libraries Government Documents Department

Novel Solvent for the Simultaneous recovery of Radioactive Nuclides from Liquid Radioactive Wastes

Description: The present invention relates to solvents, and methods, for selectively extracting and recovering radionuclides, especially cesium and strontium, rare earths and actinides from liquid radioactive wastes. More specifically, the invention relates to extracting agent solvent compositions comprising complex organoboron compounds, substituted polyethylene glycols, and neutral organophosphorus compounds in a diluent. The preferred solvent comprises a chlorinated cobalt dicarbollide, diphenyl-dibutylmethylenecarbamoylphosphine oxide, PEG-400, and a diluent of phenylpolyfluoroalkyl sulfone. The invention also provides a method of using the invention extracting agents to recover cesium, strontium, rare earths and actinides from liquid radioactive waste.
Date: October 7, 1999
Creator: Romanovskiy, Valeriy Nicholiavich; Smirnov, Lgor V.; Babain, Vasiliy A.; Todd, Terry A. & Brewer, Ken N.
Partner: UNT Libraries Government Documents Department

Pressure Gradient Passivation of Carbonaceous Material Normally Susceptible to Spontaneous Combustion

Description: This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.
Date: July 15, 1999
Creator: Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A. & Utz, Bruce R.
Partner: UNT Libraries Government Documents Department

Ceramic Composition for Immobilization of Actinides

Description: Disclosed is a ceramic composition for the immobilization of actinides, particularly uranium and plutonium. The ceramic is a titanate material comprising pyrochlore, brannerite and rutile.
Date: June 22, 1999
Creator: Ebbinghaus, Bartley B.; Van Konynenburg, Richard A.; Vance, Eric R.; Stewart, Martin W.; Jostsons, Adam; Allender, Jeffrey S. et al.
Partner: UNT Libraries Government Documents Department

Ultrasonic Sensor and Method of use

Description: An ultrasonic sensor system and method of use for measuring transit time through a liquid sample, comprising at least one ultrasonic transducer coupled to a precision time interval counter. The timing circuit captures changes in transit time, representing small changes in the velocity of sound transmitted, over necessarily small time intervals (nanoseconds) and uses the transit time changes to identify the presence of non-conforming constituents in the sample.
Date: July 22, 1999
Creator: Condreva, Kenneth J.
Partner: UNT Libraries Government Documents Department

Method of Forming Diamonds from Carbonaceous Material

Description: A method for producing diamonds is provided comprising exposing carbonaceous material to ion irradiation at ambient temperature and pressure.
Date: November 30, 1999
Creator: Daulton, Tyrone; Lewis, Roy; Rehn, Lynn & Kirk, Marquis
Partner: UNT Libraries Government Documents Department

Low Temperature Sorbents for removal of Sulfur Compounds from fluid feed Streams

Description: A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200 C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.
Date: September 30, 1999
Creator: Siriwardane, Ranjan
Partner: UNT Libraries Government Documents Department

Gas-Driven Microturbine

Description: The present invention is directed to a means of fabricating a gas-driven microturbine that is capable of providing autonomous propulsion in which the rapidly moving gases are directed through a micromachined turbine to power mechanical, electrical, or electromechanical devices by direct mechanical linkage of turbo-electric generator components in a domain ranging from tenths of micrometers to thousands of micrometers. By optimally selecting monopropellants or bipropellants to be the fuel set, a more efficient gas-driven microturbine can be realized from the increased mass flow rate of the gas stream due to the higher combustion reaction energies of these fuel sets. Additionally, compressed gas can be utilized to provide a high-flow gas stream for the gas-driven microturbine. The present invention is adaptable to many defense and non-defense applications, including the provision of mechanical power for miniature devices such as fans, geared mechanisms, mechanical linkages, actuators, bio-medical procedures, manufacturing, industrial, aviation, computers, safety systems, and electrical generators.
Date: July 14, 1999
Creator: Sniegowski, Jeffrey J.; Rodgers, Murray S.; McWhorter, Paul J.; Aeschliman, Daniel P. & Miller, William M.
Partner: UNT Libraries Government Documents Department

Fluidtight Seal for a Container

Description: A fluidtight seal for a container is formed by abutting a metal ring with a step machined in a convexo-concave container closure device and inserting this assembly into an open end of the container. Under compressive force, the closure device deforms causing the metal ring to pivot about the step on the closure device and interact with symmetrically tapered inner walls of the container to form a fluidtight seal between the container and the closure device. The compressive force is then withdrawn without affecting the fluidtight characteristic of the seal. A destructive force against the container closure device is necessary to destroy the fluidtight seal.
Date: March 31, 1999
Creator: Morrison, Edward F.
Partner: UNT Libraries Government Documents Department

Near-Electrode Imager

Description: An apparatus, near-electrode imager, for employing nuclear magnetic resonance imaging to provide in situ measurements of electrochemical properties of a sample as a function of distance from a working electrode. The near-electrode imager use the radio frequency field gradient within a cylindrical toroid cavity resonator to provide high-resolution nuclear magnetic resonance spectral information on electrolyte materials.
Date: May 1, 1999
Creator: Rathke, Jerome W.; Klingler, Robert J.; Woelk, Klaus & Gerald, Rex E.,II
Partner: UNT Libraries Government Documents Department

Process for Making a Ceramic Composition for Immobilization of Actinides

Description: Disclosed is a process for making a ceramic composition for the immobilization of actinides, particularly uranium and plutonium. The ceramic is a titanate material comprising pyrochlore, brannerite and rutile. The process comprises oxidizing the actinides, milling the oxides to a powder, blending them with ceramic precursors, cold pressing the blend and sintering the pressed material.
Date: June 22, 1999
Creator: Ebbinghaus, Bartley B.; Van Konynenburg, Richard A.; Vance, Eric R.; Stewart, Martin W.; Walls, Philip A.; Brummond, William Allen et al.
Partner: UNT Libraries Government Documents Department

Method for Producing Chemically Bonded Phosphate Ceramics and for Stabilizing Contaminants Encapsulated therein Utilizing Reducing Agents

Description: Known phosphate ceramic formulations are improved and the ability to produce iron-based phosphate ceramic systems is enabled by the addition of an oxidizing or reducing step during the acid-base reactions that form the phosphate ceramic products. The additives allow control of the rate of the acid-base reactions and concomitant heat generation. In an alternate embodiment, waste containing metal anions is stabilized in phosphate ceramic products by the addition of a reducing agent to the phosphate ceramic mixture. The reduced metal ions are more stable and/or reactive with the phosphate ions, resulting in the formation of insoluble metal species within the phosphate ceramic matrix, such that the resulting chemically bonded phosphate ceramic product has greater leach resistance.
Date: May 5, 1999
Creator: Singh, Dileep; Wagh, Arun S. & Jeong, Seung-Young
Partner: UNT Libraries Government Documents Department

Bi-Stable Optical Actuator

Description: The present invention is a bi-stable optical actuator device that is depowered in both stable positions. A bearing is used to transfer motion and smoothly transition from one state to another. The optical actuator device may be maintained in a stable position either by gravity or a restraining device.
Date: October 15, 1999
Creator: Holdener, Fred R. & Boyd, Robert D.
Partner: UNT Libraries Government Documents Department

A Monolithic Interconnected module with a tunnel Junction for Enhanced Electrical and Optical Performance

Description: An improved thermophotovoltaic (TPV) n/p/n device is provided. Monolithic Interconnected Modules (MIMs), semiconductor devices converting infrared radiation to electricity, have been developed with improved electrical and optical performance. The structure is an n-type emitter on a p-type base with an n-type lateral conduction layer. The incorporation of a tunnel junction and the reduction in the amount of p-type material used results in negligible parasitic absorption, decreased series resistance, increased voltage and increased active area. The novel use of a tunnel junction results in the potential for a TPV device with efficiency greater than 24%.
Date: June 30, 1999
Creator: Murray, Christopher Sean & Wilt, David Morgan
Partner: UNT Libraries Government Documents Department

Method for Non-Intrusively Identifying a Contained Material Utilizing Uncollided Nuclear Transmission Measurements

Description: An improved nuclear diagnostic method identifies a contained target material by measuring on-axis, mono-energetic uncollided particle radiation transmitted through a target material for two penetrating radiation beam energies, and applying specially developed algorithms to estimate a ratio of macroscopic neutron cross-sections for the uncollided particle radiation at the two energies, where the penetrating radiation is a neutron beam, or a ratio of linear attenuation coefficients for the uncollided particle radiation at the two energies, where the penetrating radiation is a gamma-ray beam. Alternatively, the measurements are used to derive a minimization formula based on the macroscopic neutron cross-sections for the uncollided particle radiation at the two neutron beam energies, or the linear attenuation coefficients for the uncollided particle radiation at the two gamma-ray beam energies. A candidate target material database, including known macroscopic neutron cross-sections or linear attenuation coefficients for target materials at the selected neutron or gamma-ray beam energies, is used to approximate the estimated ratio or to solve the minimization formula, such that the identity of the contained target material is discovered.
Date: February 26, 1999
Creator: Morrison, John L.; Stephens, Alan G. & S., Grover Blaine
Partner: UNT Libraries Government Documents Department

Oxidation-resistant interfacial coatings for fiber-reinforced ceramic composites

Description: A ceramic-matrix composite having a multilayered interfacial coating adapted to protect the reinforcing fibers from long-term oxidation, while allowing these to bridge the wake of advancing cracks in the matrix, is provided by selectively mismatching materials within adjacent layers of the interfacial coating, the materials having different coefficients of thermal expansion so that a low toughness interface region is created to promote crack deflection either within an interior layer of the mismatched interfacial coating or between adjacent layers of the mismatched interfacial coating.
Date: April 22, 1999
Creator: Lara-Curzio, Edgar; More, Karren L. & Lee, Woo Y.
Partner: UNT Libraries Government Documents Department

X-Ray Imaging Crystal Spectrometer for Extended X-Ray Sources

Description: Spherically or toroidally curved, double focusing crystals are used in a spectrometer for X-ray diagnostics of an extended X-ray source such as a hot plasma produced in a tokamak fusion experiment to provide spatially and temporally resolved data on plasma parameters such as ion temperature, toroidal and poloidal rotation, electron temperature, impurity ion charge-state distributions, and impurity transport. The imaging properties of these spherically or toroidally curved crystals provide both spectrally and spatially resolved X-ray data from the plasma using only one small spherically or toroidally curved crystal, thus eliminating the requirement for a large array of crystal spectrometers and the need to cross-calibrate the various crystals.
Date: May 1, 1999
Creator: Bitter, Manfred L.; Fraekel, Benjamin; Gorman, James L.; Hill, Kenneth W.; Roquemore, Lane A.; Stodiek, Wolfgang et al.
Partner: UNT Libraries Government Documents Department

New Carbon Activation Process for Increased Surface Accessibility in Electrochemical Capacitors

Description: A process for making carbon film or powder suitable for double capacitor electrodes having a capacitance of up to about 300 F/cm{sup 3} is disclosed. This is accomplished by treating in aqueous nitric acid for a period of about 5 to 15 minutes thin carbon films obtained by carbonizing carbon-containing polymeric material having a high degree of molecular directionality, such as polyimide film, then heating the treated carbon film in a non-oxidizing atmosphere at a non-graphitizing temperature of at least 350 C for about 20 minutes, and repeating alternately the nitric acid step and the heating step from 7 to 10 times. Capacitors made with this carbon may find uses ranging from electronic devices to electric vehicle applications.
Date: March 16, 1999
Creator: Doughty, Daniel H. & Eisenmann, Erhard T.
Partner: UNT Libraries Government Documents Department

Vacuum Enhanced Cutaneous Biopsy Instrument

Description: A syringe-like disposable cutaneous biopsy instrument equipped with a tubular blade at its lower end, and designed so that a vacuum is created during use, said vacuum serving to retain undeformed a plug of tissue cut from a patient's skin.
Date: June 25, 1999
Creator: Collins, Joseph
Partner: UNT Libraries Government Documents Department

Thermionic Converter Temperature Controller

Description: A method and apparatus for controlling the temperature of a thermionic reactor over a wide range of operating power, including a thermionic reactor having a plurality of integral cesium reservoirs, a honeycomb material disposed about the reactor which has a plurality of separated cavities, a solid sheath disposed about the honeycomb material and having an opening therein communicating with the honeycomb material and cavities thereof, and a shell disposed about the sheath for creating a coolant annulus therewith so that the coolant in the annulus may fill the cavities and permit nucleate boiling during the operation of the reactor.
Date: August 23, 1999
Creator: Shaner,B. J.; Wolf, Joseph H. & Johnson, Robert G. R.
Partner: UNT Libraries Government Documents Department