Patents by Inventor Robert G. Mendenhall

Robert G. Mendenhall 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: 7182925
    Abstract: A method for the dissolution and purification of tantalum ore and synthetic concentrates is described. The method preferably uses ammonium bifluoride as the fluoride source in place of the hydrofluoric acid used in the conventional methods. Other fluoride compounds such as NaF, KF, and CaF2 may be used alone or in combination with ammonium bifluoride. The tantalum concentrate and fluoride source are combined with sulfuric acid to form a solution containing tantalum values and impurities. The tantalum values are then separated from the impurities by solvent extraction.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: February 27, 2007
    Assignee: Osram Sylvania Inc.
    Inventors: Raj P. Singh Gaur, Robert G. Mendenhall
  • Patent number: 7060648
    Abstract: A tungsten-containing fuel cell catalyst having high electrochemical activity and its method of making are described. The tungsten-containing catalyst may be formed in situ in a fuel cell after the fuel cell is assembled.
    Type: Grant
    Filed: July 31, 2003
    Date of Patent: June 13, 2006
    Assignee: Osram Sylvania Inc.
    Inventors: Joel B. Christian, Robert G. Mendenhall
  • Publication number: 20040213716
    Abstract: A method for the dissolution and purification of tantalum ore and synthetic concentrates is described. The method preferably uses ammonium bifluoride as the fluoride source in place of the hydrofluoric acid used in the conventional methods. Other fluoride compounds such as NaF, KF, and CaF2 may be used alone or in combination with ammonium bifluoride. The tantalum concentrate and fluoride source are combined with sulfuric acid to form a solution containing tantalum values and impurities. The tantalum values are then separated from the impurities by solvent extraction.
    Type: Application
    Filed: April 22, 2004
    Publication date: October 28, 2004
    Applicant: OSRAM SYLVANIA INC.
    Inventors: Raj P. Singh Gaur, Robert G. Mendenhall
  • Patent number: 6737035
    Abstract: A high-surface-area heterogenite (HCoO2) material is described for use in making submicron cobalt metal powders. The HCoO2 material has a surface area of at least about 90 M2/g and is preferably produced by dehydrating a cobalt hydroxide precipitate at 110° C.
    Type: Grant
    Filed: August 31, 2000
    Date of Patent: May 18, 2004
    Assignee: Osram Sylvania Inc.
    Inventors: Raj P. Singh, Robert G. Mendenhall
  • Patent number: 6696184
    Abstract: A supported tungsten carbide material is provided. The material has a unique structure as defined by its x-ray diffraction pattern and consists of extremely small crystallites on the order of about 15 to about 30 angstroms in size. The tungsten carbide material is supported on a high-surface-area support to allow for a greater number of active sites for catalysis. The support consists preferably of a high-surface-area carbon.
    Type: Grant
    Filed: September 29, 2000
    Date of Patent: February 24, 2004
    Assignee: Osram Sylvania Inc.
    Inventors: Joel B. Christian, Tuan A. Dang, Robert G. Mendenhall
  • Publication number: 20040023795
    Abstract: A tungsten-containing fuel cell catalyst having high electrochemical activity and its method of making are described. The tungsten-containing catalyst may be formed in situ in a fuel cell after the fuel cell is assembled.
    Type: Application
    Filed: July 31, 2003
    Publication date: February 5, 2004
    Inventors: Joel B. Christian, Robert G. Mendenhall
  • Patent number: 6660184
    Abstract: A phosphor paste composition for plasma display panels (PDP) is provided which comprises a phosphor dispersed in an organic paste comprising a solvent, a binder, at least one dispersant comprising stearic acid, and a plasticizer. The paste compositions are very stable and have desirable screen-printing properties. In addition, the phosphor contained in the paste retains a high percentage of its initial brightness following binder burn-out.
    Type: Grant
    Filed: December 13, 2001
    Date of Patent: December 9, 2003
    Assignee: Osram Sylvania Inc.
    Inventors: Raj P. Singh, Robert G. Mendenhall, Diane C. Seymour
  • Patent number: 6656870
    Abstract: A tungsten-containing fuel cell catalyst having high electrochemical activity and its method of making are described. The tungsten-containing catalyst may be formed in situ in a fuel cell after the fuel cell is assembled.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: December 2, 2003
    Assignee: Osram Sylvania Inc.
    Inventors: Joel B. Christian, Robert G. Mendenhall
  • Patent number: 6596051
    Abstract: A high-surface-area heterogenite (HCoO2) material is described for use in making submicron cobalt metal powders. The HCoO2 material has a surface area of at least about 90 m2/g and is preferably produced by dehydrating a cobalt hydroxide precipitate at 110° C.
    Type: Grant
    Filed: September 27, 2001
    Date of Patent: July 22, 2003
    Assignee: Osram Sylvania Inc.
    Inventors: Raj P. Singh, Robert G. Mendenhall
  • Publication number: 20030111642
    Abstract: A phosphor paste composition for plasma display panels (PDP) is provided which comprises a phosphor dispersed in an organic paste comprising a solvent, a binder, at least one dispersant comprising stearic acid, and a plasticizer. The paste compositions are very stable and have desirable screen-printing properties. In addition, the phosphor contained in the paste retains a high percentage of its initial brightness following binder burn-out.
    Type: Application
    Filed: December 13, 2001
    Publication date: June 19, 2003
    Inventors: Raj P. Singh, Robert G. Mendenhall, Diane C. Seymour
  • Publication number: 20030077460
    Abstract: A supported tungsten carbide material is provided. The material has a unique structure as defined by its x-ray diffraction pattern and consists of extremely small crystallites on the order of about 15 to about 30 angstroms in size. The tungsten carbide material is supported on a high-surface-area support to allow for a greater number of active sites for catalysis. The support consists preferably of a high-surface-area carbon.
    Type: Application
    Filed: September 28, 2001
    Publication date: April 24, 2003
    Inventors: Joel B. Christian, Tuan A. Dang, Robert G. Mendenhall
  • Patent number: 6551569
    Abstract: A supported tungsten carbide material is provided. The material has a unique structure as defined by its x-ray diffraction pattern and consists of extremely small crystallites on the order of about 15 to about 30 angstroms in size. The tungsten carbide material is supported on a high-surface-area support to allow for a greater number of active sites for catalysis. The support consists preferably of a high-surface-area carbon.
    Type: Grant
    Filed: September 28, 2001
    Date of Patent: April 22, 2003
    Assignee: Osram Sylvania Inc.
    Inventors: Joel B. Christian, Tuan A. Dang, Robert G. Mendenhall
  • Publication number: 20020111267
    Abstract: A tungsten-containing fuel cell catalyst having high electrochemical activity and its method of making are described. The tungsten-containing catalyst may be formed in situ in a fuel cell after the fuel cell is assembled.
    Type: Application
    Filed: September 27, 2001
    Publication date: August 15, 2002
    Applicant: OSRAM SYLVANIA Inc.
    Inventors: Joel B. Christian, Robert G. Mendenhall
  • Publication number: 20020043132
    Abstract: A high-surface-area heterogenite (HCoO2) material is described for use in making submicron cobalt metal powders. The HCoO2 material has a surface area of at least about 90 m2/g and is preferably produced by dehydrating a cobalt hydroxide precipitate at 110° C.
    Type: Application
    Filed: September 27, 2001
    Publication date: April 18, 2002
    Inventors: Raj P. Singh, Robert G. Mendenhall
  • Patent number: 5244156
    Abstract: In a process for reducing the dust content of cobalt metal powder, the starting cobalt powder containing dust is milled for a sufficient period of time to increase the bulk density and decrease the dust content while substantially maintaining the original Fisher Sub Sieve Size.
    Type: Grant
    Filed: November 20, 1990
    Date of Patent: September 14, 1993
    Assignee: GTE Products Corporation
    Inventors: Robert G. Mendenhall, Michael J. Miller
  • Patent number: 5185133
    Abstract: A method is disclosed for producing fine size molybdenum trioxide powder which involves heating ammonium dimolybdate in ambient atmosphere at a temperature of from about 455.degree. C. to about 465.degree. C. for a time of from about 5 hours to about 6 hours to produce a first molybdenum trioxide which is granulated to about -10 mesh and then heated in a furnace in which there are three heating zones. The first molybdenum trioxide is heated in the first heating zone at a temperature of from about 550.degree. C. to about 590.degree. C., in the second heating zone at a temperature of from about 580.degree. C. to about 610.degree. C. and thereafter in the third heating zone at a temperature of from about 580.degree. C. to about 625.degree. C., with the feed rate of material in the three zones being from about 1.5 to about 3.0 kg/hr to produce a yellow molybdenum trioxide. The yellow molybdenum trioxide is then cooled and granulated to about -40 mesh.
    Type: Grant
    Filed: August 23, 1988
    Date of Patent: February 9, 1993
    Assignee: GTE Products Corporation
    Inventors: Judy L. Scheftic, Robert G. Mendenhall, Michael J. Chereslowsky
  • Patent number: 5045121
    Abstract: A method is disclosed for removing carbon from the surface of a cemented tungsten carbide article which comprises contacting a cemented tungsten carbide article with an aqueous solution of hydrogen peroxide having a concentration of at least about 5% by volume hydrogen perioxide for a sufficient length of time to remove the major portion of the carbon from the surfaces of the article.
    Type: Grant
    Filed: February 4, 1991
    Date of Patent: September 3, 1991
    Assignee: GTE Products Corporation
    Inventors: Timothy J. Hoffman, Robert G. Mendenhall, Michael J. Cheresnowsky