Patents by Inventor Roger M. Williams

Roger M. Williams has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5698771
    Abstract: A hydrocarbon gas detection device operates by dissociating or electro-chemically oxidizing hydrocarbons adsorbed to a silicon carbide detection layer. Dissociation or oxidation are driven by a varying potential applied to the detection layer. Different hydrocarbon species undergo reaction at different applied potentials so that the device is able to discriminate among various hydrocarbon species. The device can operate at temperatures between 100.degree. C. and at least 650.degree. C., allowing hydrocarbon detection in hot exhaust gases. The dissociation reaction is detected either as a change in a capacitor or, preferably, as a change of current flow through an FET which incorporates the silicon carbide detection layers. The silicon carbide detection layer can be augmented with a pad of catalytic material which provides a signal without an applied potential. Comparisons between the catalytically produced signal and the varying potential produced signal may further help identify the hydrocarbon present.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: December 16, 1997
    Assignee: The United States of America as represented by the United States National Aeronautics and Space Administration
    Inventors: Virgil B. Shields, Margaret A. Ryan, Roger M. Williams
  • Patent number: 5441575
    Abstract: An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.
    Type: Grant
    Filed: January 11, 1993
    Date of Patent: August 15, 1995
    Assignee: The United States of America as represented by the United States National Aeronautics and Space Administration
    Inventors: Mark L. Underwood, Roger M. Williams, Margaret A. Ryan, Barbara J. Nakamura, Dennis E. O'Connor
  • Patent number: 5278636
    Abstract: A bistable switching element is made of a material whose electrical resistance reversibly decreases in response to intercalation by positive ions. Flow of positive ions between the bistable switching element and a positive ion source is controlled by means of an electrical potential applied across a thermal switching element. The material of the thermal switching element generates heat in response to electrical current flow therethrough, which in turn causes the material to undergo a thermal phase transition from a high electrical resistance state to a low electrical resistance state as the temperature increases above a predetermined value. Application of the electrical potential in one direction renders the thermal switching element conductive to pass electron current out of the ion source. This causes positive ions to flow from the source into the bistable switching element and intercalate the same to produce a non-volatile, low resistance logic state.
    Type: Grant
    Filed: January 28, 1991
    Date of Patent: January 11, 1994
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Roger M. Williams
  • Patent number: 4966823
    Abstract: A liquid catholyte for a battery based on liquid metal such as sodium anode and a solid, ceramic separator such as beta alumina (BASE) comprises a mixture of a Group I-III metal salt such as sodium tetrachloroaluminate and a minor amount of an organic carbonitrile depolarizer having at least one adjacent ethylenic bond such as 1 to 40 percent by weight of tetracyanoethylene. The tetracyanoethylene forms an adduct with the molten metal salt.
    Type: Grant
    Filed: September 7, 1989
    Date of Patent: October 30, 1990
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Ratnakumar V. Bugga, Salvador DiStefano, Roger M. Williams, Clyde P. Bankston
  • Patent number: 4871626
    Abstract: An electrode having higher power output is formed of an open mesh current collector such as expanded nickel covering an electrode film applied to a tube of beta-alumina solid electrolyte (BASE). A plurality of cross-members such as spaced, parallel loops of molybdenum metal wire surround the BASE tube. The loops are electrically connected by a bus wire. As the AMTEC cell is heated, the grid of expanded nickel expands more than the BASE tube and the surrounding loop of wire and become diffusion welded to the electrode film and to the wire loops.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: October 3, 1989
    Assignee: California Institute of Technology
    Inventor: Roger M. Williams
  • Patent number: 4835071
    Abstract: An electrode having higher power output is formed of a thin, porous film (less than 1 micrometer) applied to a beta-alumina solid electrolyte (BASE). The electrode includes an open grid, current collector such as a series of thin, parallel, grid lines applied to the thin film and a plurality of cross-members such as loop of metal wire surrounding the BASE tube. The loops are electrically connected by a bus wire. The overall impedance of the electrode considering both the contributions from the bulk BASE and the porous electrode BASE interface is low, about 0.5 OHM/cm.sup.2 and power densities of over 0.3 watt/cm.sup.2 for extended periods.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: May 30, 1989
    Assignee: California Institute of Technology
    Inventors: Roger M. Williams, Bob L. Wheeler, Barbara Jefferies-Nakamura, James L. Lamb, C. Perry Bankston, Terry Cole
  • Patent number: 4820596
    Abstract: An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.
    Type: Grant
    Filed: August 6, 1987
    Date of Patent: April 11, 1989
    Assignee: California Institute of Technology
    Inventors: Roger M. Williams, Clyde P. Bankston, Terry Cole, Satish K. Khanna, Barbara Jeffries-Nakamura, Bob L. Wheeler
  • Patent number: 4522844
    Abstract: Disclosed is a method of coating a substrate with an amorphous metal comprising the step of bombarding a solid piece of the metal with ions of an inert gas in the presence of a magnetic field to provide a vapor of the metal which is deposited on the substrate at a sufficiently low gas pressure so that there is formed on the substrate a thin, uniformly thick, essentially pinhole-free film of the metal.
    Type: Grant
    Filed: September 30, 1983
    Date of Patent: June 11, 1985
    Assignee: The United States of America as represented by the Administrator, National Aeronautics and Space Administration
    Inventors: Satish K. Khanna, Anilkumar P. Thakoor, Roger M. Williams
  • Patent number: 4414080
    Abstract: The surface (20) of a moderate band gap semiconductor (12) such as p-type molybdenum sulfide is modified to contain an adherent film (24) of charge mediating ionene polymer containing an electroactive unit such as bipyridinium. Electron transport between the electrode (12) and the mediator film (24) is favorable and photocorrosion and recombination processes are suppressed. Incorporation of particles (26) of catalyst such as platinum within the film (24) provides a reduction in overvoltage. The polymer film is readily deposited on the electrode surface and can be rendered stable by ionic or addition cross-linking. Catalyst can be predispersed in the polymer film or a salt can be impregnated into the film and reduced therein.
    Type: Grant
    Filed: May 10, 1982
    Date of Patent: November 8, 1983
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventors: Roger M. Williams, Alan Rembaum
  • Patent number: 4192973
    Abstract: This invention is concerned with a processor-overload relief facility in a time division multiplex (t.d.m.) processor-controlled exchanges. Under overload conditions rejection of new calls may be required until this condition is relieved and this proposal is to meet the relief function by peripheral hardware while retaining the ability to process emergency (999) calls during overload. An incoming signalling unit which is responsive to incoming seize, dialling and other signals, is provided with multi-bit stores on a one per channel basis; each such store interfacing with processor on a read/write basis. Normally the signalling unit responds to any incoming channel-seized condition and sets the `seize` bit (S) in the appropriate channel store which reports seizure to the processor. Dialled pulses are detected and accumulated in the store, and each complete digit is transferred to the processor for call control purposes.
    Type: Grant
    Filed: January 13, 1978
    Date of Patent: March 11, 1980
    Assignee: Plessey Handel und Investments AG
    Inventors: Roger M. Williams, Alan J. Lawrence