Patents Assigned to Midwest Research Institute
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Patent number: 5484736Abstract: A process for producing a cadmium telluride polycrystalline film having grain sizes greater than about 20 .mu.m. The process comprises providing a substrate upon which cadmium telluride can be deposited and placing that substrate within a vacuum chamber containing a cadmium telluride effusion cell. A polycrystalline film is then deposited on the substrate through the steps of evacuating the vacuum chamber to a pressure of at least 10.sup.-6 torr.; heating the effusion cell to a temperature whereat the cell releases stoichiometric amounts of cadmium telluride usable as a molecular beam source for growth of grains on the substrate; heating the substrate to a temperature whereat a stoichiometric film of cadmium telluride can be deposited; and releasing cadmium telluride from the effusion cell for deposition as a film on the substrate.Type: GrantFiled: September 19, 1994Date of Patent: January 16, 1996Assignee: Midwest Research InstituteInventors: Falah S. Hasoon, Art J. Nelson
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Patent number: 5477676Abstract: A catalytic converter is surrounded by variable conductance insulation for maintaining the operating temperature of the catalytic converter at an optimum level, for inhibiting heat loss when raising catalytic converter temperature to light-off temperature, for storing excess heat to maintain or accelerate reaching light-off temperature, and for conducting excess heat away from the catalytic converter after reaching light-off temperature. The variable conductance insulation includes vacuum gas control and metal-to-metal thermal shunt mechanisms. Radial and axial shielding inhibits radiation and convection heat loss. Thermal storage media includes phase change material, and heat exchanger chambers and fluids carry heat to and from the catalytic converter.Type: GrantFiled: January 27, 1994Date of Patent: December 26, 1995Assignee: Midwest Research InstituteInventors: David K. Benson, Thomas F. Potter
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Patent number: 5476837Abstract: A process for preparing a superconducting film, such as a thallium-barium-calcium-copper oxide superconducting film, having substantially uniform phase development. The process comprises providing an electrodeposition bath having one or more soluble salts of one or more respective potentially superconducting metals in respective amounts adequate to yield a superconducting film upon subsequent appropriate treatment. Should all of the metals required for producing a superconducting film not be made available in the bath, such metals can be a part of the ambient during a subsequent annealing process. A soluble silver salt in an amount between about 0.1% and about 4.0% by weight of the provided other salts is also provided to the bath, and the bath is electrically energized to thereby form a plated film. The film is annealed in ambient conditions suitable to cause formation of a superconductor film.Type: GrantFiled: March 14, 1994Date of Patent: December 19, 1995Assignee: Midwest Research InstituteInventors: Raghuthan Bharacharya, Philip A. Parilla, Richard D. Blaugher
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Patent number: 5464602Abstract: A process of pyrolyzing plastic waste feed streams containing polyvinyl chloride, polyethylene terephthalate, polystyrene and polyethylene to recover polystyrene HCl and terephthalic acid comprising: heating the plastic waste feed stream to a first temperature; adding an acid or base catalyst on an oxide or carbonate support; heating the plastic waste feed stream to pyrolyze polyethylene terephthalate and polyvinyl chloride; separating terephthalic acid or HCl; heating to a second temperature to pyrolyze polystyrene; separating styrene; heating the waste feed stream to a third temperature to pyrolyze polyethylene; and separating hydrocarbons.Type: GrantFiled: January 9, 1995Date of Patent: November 7, 1995Assignee: Midwest Research InstituteInventors: Robert J. Evans, Helena L. Chum
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Patent number: 5462647Abstract: A process for the preparation of lead-zirconium-titanium (PZT) film and powder compositions. The process comprises the steps of providing an electrodeposition bath, providing soluble salts of lead, zirconium and titanium metals to this bath, electrically energizing the bath to thereby direct ions of each respective metal to a substrate electrode and cause formation of metallic particles as a recoverable film of PZT powder on the electrode, and also recovering the resultant film as a powder. Recovery of the PZT powder can be accomplished by continually energizing the bath to thereby cause powder initially deposited on the substrate-electrode to drop therefrom into the bath from which it is subsequently removed. A second recovery alternative comprises energizing the bath for a period of time sufficient to cause PZT powder deposition on the substrate-electrode only, from which it is subsequently recovered.Type: GrantFiled: September 9, 1994Date of Patent: October 31, 1995Assignee: Midwest Research InstituteInventors: Raghu N. Bhattacharya, David S. Ginley
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Patent number: 5456205Abstract: A system for monitoring the growth of crystalline films on stationary or rotating substrates includes a combination of some or all of the elements including a photodiode sensor for detecting the intensity of incoming light and converting it to a measurable current, a lens for focusing the RHEED pattern emanating from the phosphor screen onto the photodiode, an interference filter for filtering out light other than that which emanates from the phosphor screen, a current amplifier for amplifying and converting the current produced by the photodiode into a voltage, a computer for receiving the amplified photodiode current for RHEED data analysis, and a graphite impregnated triax cable for improving the signal to noise ratio obtained while sampling a stationary or rotating substrate. A rotating stage for supporting the substrate with diametrically positioned electron beam apertures and an optically encoded shaft can also be used to accommodate rotation of the substrate during measurement.Type: GrantFiled: June 1, 1993Date of Patent: October 10, 1995Assignee: Midwest Research InstituteInventor: Peter Sheldon
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Patent number: 5453530Abstract: Compounds are described which are S-(.omega.-hydroxyalkyl) esters of thioacrylic and thiomethacrylic acids. The compounds have the formula: ##STR1## wherein: R is hydrogen or methyl; andn is 1, 2 or 3.These compounds can be used as conditioners to enhance the wettability of dentinal surfaces, can be employed as chemical tracers to characterize the wetting of dentinal surfaces, and can be copolymerized in situ to form potential dentinal bonding systems. The compounds can also be homopolymerized and copolymerized to form other useful products.Type: GrantFiled: March 11, 1994Date of Patent: September 26, 1995Assignees: The Curators of the University of Missouri, Midwest Research InstituteInventors: Thomas J. Byerley, Cecil C. Chappelow, J. David Eick
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Patent number: 5452396Abstract: An optical furnace for annealing a process wafer comprising a source of optical energy, a quartz muffle having a door to hold the wafer for processing, and a quartz diffuser plate to diffuse the light impinging on the quartz muffle; a feedback system with a light sensor located in the door or wall of the muffle is also provided for controlling the source of optical energy. The quartz for the diffuser plate is surface etched (to give the quartz diffusive qualities) in the furnace during a high intensity burn-in process.Type: GrantFiled: February 7, 1994Date of Patent: September 19, 1995Assignee: Midwest Research InstituteInventor: Bhushan L. Sopori
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Patent number: 5441897Abstract: A process for producing a slightly Cu-poor thin film of Cu(In,Ga)(Se,S).sub.2 comprises depositing a first layer of (In,Ga).sub.x (Se,S).sub.y followed by depositing just enough Cu+(Se,S) or Cu.sub.x (Se,S) to produce the desired slightly Cu-poor material. In a variation, most, but not all, (about 90 to 99%) of the (In,Ga).sub.x (Se,S).sub.y is deposited first, followed by deposition of all the Cu+(Se,S) or Cu.sub.x (Se,S) to go near stoichiometric, possibly or even preferably slightly Cu-rich, and then in turn followed by deposition of the remainder (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y to end with a slightly Cu-poor composition. In yet another variation, a small portion (about 1 to 10%) of the (In,Ga).sub.x (Se,S).sub.y is first deposited as a seed layer, followed by deposition of all of the Cu+(Se,S) or Cu.sub.x (Se,S) to make a very Cu-rich mixture, and then followed deposition of the remainder of the (In,Ga).sub.x (Se,S).sub.y to go slightly Cu-poor in the final Cu(In,Ga)(Se,S).sub.Type: GrantFiled: February 16, 1994Date of Patent: August 15, 1995Assignee: Midwest Research InstituteInventors: Rommel Noufi, Andrew M. Gabor, John R. Tuttle, Andrew L. Tennant, Miguel A. Contreras, David S. Albin, Jeffrey J. Carapella
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Patent number: 5436204Abstract: A process for fabricating slightly Cu-poor thin-films of Cu(In,Ga)Se.sub.2 on a substrate for semiconductor device applications includes the steps of forming initially a slightly Cu-rich, phase separated, mixture of Cu(In,Ga)Se.sub.2 :Cu.sub.x Se on the substrate in solid form followed by exposure of the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture to an overpressure of Se vapor and (In,Ga) vapor for deposition on the Cu(In,Ga)Se.sub.2 :Cu.sub.x Se solid mixture while simultaneously increasing the temperature of the solid mixture toward a recrystallization temperature (about 550.degree. C.) at which Cu(In,Ga)Se.sub.2 is solid and Cu.sub.x Se is liquid. The (In,Ga) flux is terminated while the Se overpressure flux and the recrystallization temperature are maintained to recrystallize the Cu.sub.x Se with the (In, Ga) that was deposited during the temperature transition and with the Se vapor to form the thin-film of slightly Cu-poor Cu.sub.x (In,Ga).sub.y Se.sub.z.Type: GrantFiled: August 22, 1994Date of Patent: July 25, 1995Assignee: Midwest Research InstituteInventors: David S. Albin, Jeffrey J. Carapella, John R. Tuttle, Miguel A. Contreras, Andrew M. Gabor, Rommel Noufi, Andrew L. Tennant
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Patent number: 5433056Abstract: A compact vacuum insulation panel comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning "on" and "off" the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity.Type: GrantFiled: February 14, 1994Date of Patent: July 18, 1995Assignee: Midwest Research InstituteInventors: David K. Benson, Thomas F. Potter
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Patent number: 5432276Abstract: A method is provided for preparing high purity levoglucosan from lignocellulosic pyrolysis oils derived from wood or waste newsprint. The method includes reducing wood or newsprint to fine particle sizes, treating the particles with a hot mineral acid for a predetermined period of time, and filtering off and drying resulting solid wood or newsprint material; pyrolyzing the dried solid wood or newsprint material at temperatures between about 350.degree. and 375.degree. C. to produce pyrolysis oils; treating the oils to liquid-liquid extraction with methyl isobutyl ketone to remove heavy tar materials from the oils, and to provide an aqueous fraction mixture of the oils containing primarily levoglucosan; treating the aqueous fraction mixtures with a basic metal salt in an amount sufficient to elevate pH values to a range of about 12 to about 12.Type: GrantFiled: September 2, 1993Date of Patent: July 11, 1995Assignee: Midwest Research InstituteInventor: Luc Moens
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Patent number: 5432075Abstract: A purified low molecular weight .beta.-D-glucosidase is produced from Acidothermus cellulolyticus ATCC 43068. The enzyme is water soluble, possesses activity against pNP-.beta.-D-glucopyranoside, has a high of degree of stability toward heat, exhibits optimal temperature activity at about 65.degree. C. at a pH range of from about 2 to about 7, has an inactivation temperature of about 80.degree. C. at a pH range of from about 2 to about 7 and has a molecular weight of about 50.5-54.5 kD as determineded by SDS-PAGE.Type: GrantFiled: July 15, 1994Date of Patent: July 11, 1995Assignee: Midwest Research InstituteInventors: Michael E. Himmel, Melvin P. Tucker, William S. Adney, Rafael A. Nieves
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Patent number: 5429985Abstract: A method is provided to produce a low-resistivity ohmic contact having high optical reflectivity on one side of a semiconductor device. The contact is formed by coating the semiconductor substrate with a thin metal film on the back reflecting side and then optically processing the wafer by illuminating it with electromagnetic radiation of a predetermined wavelength and energy level through the front side of the wafer for a predetermined period of time. This method produces a thin epitaxial alloy layer between the semiconductor substrate and the metal layer when a crystalline substrate is used. The alloy layer provides both a low-resistivity ohmic contact and high optical reflectance.Type: GrantFiled: January 18, 1994Date of Patent: July 4, 1995Assignee: Midwest Research InstituteInventor: Bhushan L. Sopori
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Patent number: 5426569Abstract: A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth's surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO.sub.2 and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO.sub.2 and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO.sub.2 and moisture.Type: GrantFiled: March 7, 1994Date of Patent: June 20, 1995Assignee: Midwest Research InstituteInventor: Bhushan L. Sopori
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Patent number: 5426061Abstract: A process for impurity gettering in a semiconductor substrate or device such as a silicon substrate or device. The process comprises hydrogenating the substrate or device at the back side thereof with sufficient intensity and for a time period sufficient to produce a damaged back side. Thereafter, the substrate or device is illuminated with electromagnetic radiation at an intensity and for a time period sufficient to cause the impurities to diffuse to the back side and alloy with a metal there present to form a contact and capture the impurities. The impurity gettering process also can function to simultaneously passivate defects within the substrate or device, with the defects likewise diffusing to the back side for simultaneous passivation. Simultaneously, substantially all hydrogen-induced damage on the back side of the substrate or device is likewise annihilated.Type: GrantFiled: September 6, 1994Date of Patent: June 20, 1995Assignee: Midwest Research InstituteInventor: Bhushan L. Sopori
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Patent number: 5424417Abstract: The invention relates to the prehydrolysis of lignocellulose by passing an acidic or alkaline solution through solid lignocellulosic particles with removal of soluble components as they are formed. The technique permits a less severe combination of pH, temperature and time than conventional prehydrolysis. Furthermore, greater extraction of both hemicellulose and lignin occurs simultaneously in the same reactor and under the same conditions.Type: GrantFiled: September 24, 1993Date of Patent: June 13, 1995Assignee: Midwest Research InstituteInventors: Robert W. Torget, Kiran L. Kadam, Teh-An Hsu, George P. Philippidis, Charles E. Wyman
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Patent number: 5417548Abstract: A thick airfoil for the root region of the blade of a wind turbine. The airfoil has a thickness in a range from 24%-26% and a Reynolds number in a range from 1,000,000 to 1,800,000. The airfoil has a maximum lift coefficient of 1.4-1.6 that has minimum sensitivity to roughness effects.Type: GrantFiled: January 14, 1994Date of Patent: May 23, 1995Assignee: Midwest Research InstituteInventors: James L. Tangler, Dan M. Somers
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Patent number: 5417052Abstract: A hybrid combined cycle power plant including a solar central receiver for receiving solar radiation and converting it to thermal energy. The power plant includes a molten salt heat transfer medium for transferring the thermal energy to an air heater. The air heater uses the thermal energy to preheat the air from the compressor of the gas cycle. The exhaust gases from the gas cycle are directed to a steam turbine for additional energy production.Type: GrantFiled: November 5, 1993Date of Patent: May 23, 1995Assignee: Midwest Research InstituteInventors: Desikan Bharathan, Mark S. Bohn, Thomas A. Williams
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Patent number: 5417952Abstract: A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.Type: GrantFiled: May 27, 1994Date of Patent: May 23, 1995Assignee: Midwest Research InstituteInventors: Rasit Koc, Gregory C. Glatzmaier