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Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system (open access)

Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength {lambda}{sub IF} approximately equal to the bandgap wavelength {lambda}{sub g} of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5{lambda}{sub IF} to {lambda}{sub IF} and reflect from {lambda}{sub IF} to about 2{lambda}{sub IF}; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5{lambda}{sub IF}.
Date: December 31, 1996
Creator: Brown, Edward J.; Baldasaro, Paul F. & Dziendziel, Randolph J.
System: The UNT Digital Library
A thermophotovoltaic energy conversion device (open access)

A thermophotovoltaic energy conversion device

A thermophotovoltaic device and a method for making the thermophotovoltaic device are disclosed. The device includes an n-type semiconductor material substrate having top and bottom surfaces, a tunnel junction formed on the top surface of the substrate, a region of active layers formed on top of the tunnel junction and a back surface reflector (BSR). The tunnel junction includes a layer of heavily doped n-type semiconductor material that is formed on the top surface of the substrate and a layer of heavily doped p-type semiconductor material formed on the n-type layer. An optional pseudomorphic layer can be formed between the n-type and p-type layers. A region of active layers is formed on top of the tunnel junction. This region includes a base layer of p-type semiconductor material and an emitter layer of n-type semiconductor material. An optional front surface window layer can be formed on top of the emitter layer. An optional interference filter can be formed on top of the emitter layer or the front surface window layer when it is used.
Date: December 31, 1996
Creator: Charache, G. W.; Baldasaro, P. F. & Egley, J. L.
System: The UNT Digital Library
A tube-in-tube thermophotovoltaic generator (open access)

A tube-in-tube thermophotovoltaic generator

A thermophotovoltaic device includes at least one thermal radiator tube, a cooling tube concentrically disposed within each thermal radiator tube and an array of thermophotovoltaic cells disposed on the exterior surface of the cooling tube. A shell having a first end and a second end surrounds the thermal radiator tube. Inner and outer tubesheets, each having an aperture corresponding to each cooling tube, are located at each end of the shell. The thermal radiator tube extends within the shell between the inner tubesheets. The cooling tube extends within the shell through the corresponding apertures of the two inner tubesheets to the corresponding apertures of the two outer tubesheets. A plurality of the thermal radiator tubes can be arranged in a staggered or an in-line configuration within the shell.
Date: December 31, 1996
Creator: Ashcroft, J.; Campbell, B. & Depoy, D.
System: The UNT Digital Library
Combustor oscillation attenuation via the control of fuel-supply line dynamics (open access)

Combustor oscillation attenuation via the control of fuel-supply line dynamics

Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.
Date: December 1, 1996
Creator: Richards, George A. & Gemmen, Randall S.
System: The UNT Digital Library
Electronuclear ion fusion in an ion cyclotron resonance reactor (open access)

Electronuclear ion fusion in an ion cyclotron resonance reactor

A method and apparatus for generating nuclear fusion by ion cyclotron resonance in an ion trap reactor. The reactor includes a cylindrical housing having an axial axis, an internal surface, and first and second ends. First and second end plates that are charged are respectively located at the first and second ends of the cylindrical housing. A gas layer is adsorbed on the internal surface of the cylindrical housing. Ions are desorbed from the gas layer, forming a plasma layer adjacent to the cylindrical housing that includes first ions that have a same charge sign as the first and second end plates. A uniform magnetic field is oriented along the axial axis of the cylindrical housing. Second ions, that are unlike the first ions, but have the same charge sign, are injected into the cylindrical housing along the axial axis of the cylindrical housing. A radio frequency field resonantly accelerates the injected second ions at the cyclotron resonance frequency of the second ions. The second ions circulate in increasing helical orbits and react with the first ions, at the optimum energy for nuclear fusion. The amplitude of the radio frequency field is adjusted to accelerate the second ions at a …
Date: December 1, 1996
Creator: Cowgill, Donald F.
System: The UNT Digital Library
Hydrocracking and hydroisomerization of long-chain alkanes and polyolefins over metal-promoted anion-modified transition metal oxides (open access)

Hydrocracking and hydroisomerization of long-chain alkanes and polyolefins over metal-promoted anion-modified transition metal oxides

A method is described for cracking a feedstock by contacting the feedstock with a metal-promoted anion-modified metal oxide catalyst in the presence of hydrogen gas. The metal oxide of the catalyst is one or more of ZrO{sub 2}, HfO{sub 2}, TiO{sub 2} and SnO{sub 2}, and the feedstock is principally chains of at least 20 carbon atoms. The metal-promoted anion-modified metal oxide catalyst contains one or more of Pt, Ni, Pd, Rh, Ir, Ru, (Mn and Fe) or mixtures of them present between about 0.2% to about 15% by weight of the catalyst. The metal-promoted anion-modified metal oxide catalyst contains one or more of SO{sub 4}, WO{sub 3}, or mixtures of them present between about 0.5% to about 20% by weight of the catalyst.
Date: December 1996
Creator: Venkatesh, Koppampatti R.; Hu, Jianli; Tierney, John W. & Wender, Irving
System: The UNT Digital Library
Light gas gun with reduced timing jitter (open access)

Light gas gun with reduced timing jitter

A gas gun having a prepressurized projectile held in place with a glass rod in compression is described. The glass rod is destroyed with an explosive at a precise time which allows a restraining pin to be moved by pneumatic means and free the projectile.
Date: December 1, 1996
Creator: Laabs, Gary W.; Funk, David J. & Asay, Blaine W.
System: The UNT Digital Library
Method for the photocatalytic conversion of methane (open access)

Method for the photocatalytic conversion of methane

The invention relates to a method for converting methane and water to methanol and hydrogen using visible light and a catalyst.
Date: December 1996
Creator: Noceti, R. P.; Taylor, C. E. & D'Este, J. R.
System: The UNT Digital Library
Multilayered nuclear fuel element (open access)

Multilayered nuclear fuel element

A nuclear fuel element is described which is suitable for high temperature applications comprised of a kernel of fissile material overlaid with concentric layers of impervious graphite, vitreous carbon, pyrolytic carbon and metal carbide. The kernel of fissile material is surrounded by a layer of impervious graphite. The layer of impervious graphite is then surrounded by a layer of vitreous carbon. Finally, an outer shell which includes alternating layers of pyrolytic carbon and metal carbide surrounds the layer of vitreous carbon.
Date: December 1, 1996
Creator: Schweitzer, Donald G. & Sastre, Cesar
System: The UNT Digital Library
Porous desulfurization sorbent pellets containing a reactive metal oxide and an inert zirconium compound (open access)

Porous desulfurization sorbent pellets containing a reactive metal oxide and an inert zirconium compound

Sorbent pellets for removing hydrogen sulfide from coal gas are prepared by combining a reactive oxide, in particular zinc oxide, with a zirconium compound such as an oxide, silicate, or aluminate of zirconium, and an inorganic binder and pelletizing and calcining the mixture. Alternately, the zinc oxide may be replaced by copper oxide or a combination of copper, molybdenum, and manganese oxides. The pellet components may be mixed in dry form, moistened to produce a paste, and converted to pellets by forming an aqueous slurry of the components and spray drying the slurry, or the reactive oxide may be formed on existing zirconium-containing catalyst-carrier pellets by infusing a solution of a salt of the active metal onto the existing pellets and firing at a high temperature to produce the oxide. Pellets made according to this invention show a high reactivity with hydrogen sulfide and durability such as to be useful over repeated cycles of sorption and regeneration.
Date: December 1, 1996
Creator: Gardner, Todd H. & Gasper-Galvin, Lee D.
System: The UNT Digital Library
Binder Enhanced Refuse Derived Fuel (open access)

Binder Enhanced Refuse Derived Fuel

Patent relating to refuse derived fuels and more particularly to binder enhanced refuse derived fuel pellets and utilization of such pellets in solid-fuel fired furnaces.
Date: April 12, 1995
Creator: Daugherty, Kenneth E.; Venables, Barney J. & Ohlsson, Oscar O.
System: The UNT Digital Library
Gas-driven microturbine (open access)

Gas-driven microturbine

This paper describes an invention which relates to microtechnology and the fabrication process for developing microelectrical systems. It describes a means for fabricating a gas-driven microturbine capable of providing autonomous propulsion in which the rapidly moving gases are directed through a micromachined turbine to power devices by direct linkage or turbo-electric generators components in a domain ranging from tenths of micrometers to thousands of micrometers.
Date: June 27, 1996
Creator: Sniegowski, J. J.; Rodgers, M. S.; McWhorter, P. J.; Aeschliman, D. P. & Miller, W. M.
System: The UNT Digital Library
Superconducting thermoelectric generator (open access)

Superconducting thermoelectric generator

An apparatus and method for producing electricity from heat. The present invention is a thermoelectric generator that uses materials with substantially no electrical resistance, often called superconductors, to efficiently convert heat into electrical energy without resistive losses. Preferably, an array of superconducting elements is encased within a second material with a high thermal conductivity. The second material is preferably a semiconductor. Alternatively, the superconducting material can be doped on a base semiconducting material, or the superconducting material and the semiconducting material can exist as alternating, interleaved layers of waferlike materials. A temperature gradient imposed across the boundary of the two materials establishes an electrical potential related to the magnitude of the temperature gradient. The superconducting material carries the resulting electrical current at zero resistivity, thereby eliminating resistive losses. The elimination of resistive losses significantly increases the conversion efficiency of the thermoelectric device.
Date: January 1, 1996
Creator: Metzger, John D. & El-Genk, Mohammed S.
System: The UNT Digital Library