Patents by Inventor Daniel D. Lawson

Daniel D. Lawson 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: 5002894
    Abstract: The lignin content of wood, paper pulp or other material containing lignin (such as filter paper soaked in black liquor) is more readily determined by flash pyrolysis of the sample at approximately 550.degree. C. in a reducing atmosphere of hydrogen or in an inert atmosphere of helium followed by a rapid analysis of the product gas by a mass spectrometer. The heated pyrolysis unit as fabricated comprises a small platinum cup welded to an electrically-heated stainless steel ribbon with control means for programmed short duration (1.5 sec, approximately) heating and means for continuous flow of hydrogen or helium. The pyrolysis products enter an electron-ionization mode mass spectrometer for spectral evaluation. Lignin content is obtained from certain ratios of integrated ion currents of many mass spectral lines, the ratios being linearly related to the Kappa number of Klason lignin.
    Type: Grant
    Filed: June 6, 1988
    Date of Patent: March 26, 1991
    Inventors: Parthasarathy Shakkottai, Eug Y. Kwack, Daniel D. Lawson
  • Patent number: 4915816
    Abstract: The polymer hygrometer with lithium doped Nafion was developed to meet the need for a reliable sensor for determining the relative humidity in harsh environments of pulp and paper mills. The sensor can operate in atmospheres that have organic vapors and dust, is unaffected by sulphur dioxide, acidic vapors and strong oxidizing agents. Exceptional stability is shown by the sensor which has withstood twelve months of continuous operation in a paper mill drier duct at temperatures near 65.degree. C. and air flow velocity of 10 m/s with no degradation or calibration change. Materials used in construction of the sensor such as glass, silver filled epoxy, Teflon, platinum wire, and Nafion contribute to ruggedness and immunity to harsh environments.
    Type: Grant
    Filed: September 6, 1988
    Date of Patent: April 10, 1990
    Inventors: Parthasarathy Shakkottai, Daniel D. Lawson, Shakkottai P. Venkateshan
  • Patent number: 4753654
    Abstract: An intraocular lens capable of absorbing ultraviolet radiation and, additionally, a method for forming the lens is provided. The intraocular lens comprises a polymer matrix that is biocompatible with body tissue and fluids and comprises polymethylmethacrylate and a chromophoric compound. The intraocular lens preferably has about the same capability for absorbing ultraviolet radiation as does the natural crystalline lens of the eye. In one embodiment, the intraocular lens is formed by co-polymerizing a polymerizable derivate of 2,4-dihydroxybenzophenone and methyl methacrylate monomer to form an ultraviolet light absorbing co-polymer additive. The co-polymer additive is mixed with methyl methacrylate monomer for forming a prepolymer solution that is then cured. The intraocular lens is formed from the solid cured co-polymer.
    Type: Grant
    Filed: December 31, 1986
    Date of Patent: June 28, 1988
    Assignee: Optical Radiation Corporation
    Inventors: Thomas Posin, Daniel D. Lawson
  • Patent number: 4636212
    Abstract: An intraocular lens capable of absorbing ultraviolet radiation and, additionally, a method for forming the lens is provided. The intraocular lens comprises a polymer matrix that is biocompatible with body tissue and fluids and comprises polymethylmethacrylate and a chromophoric compound. The intraocular lens preferably has about the same capability for absorbing ultraviolet radiation as does the natural crystalline lens of the eye. In one embodiment, the intraocular lens is formed by co-polymerizing a polymerizable derivate of 2,4-dihydroxybenzophenone and methyl methacrylate monomer to form an ultraviolet light absorbing co-polymer additive. The co-polymer additive is mixed with methyl methacrylate monomer for forming a prepolymer solution that is then cured. The intraocular lens is formed from the solid cured co-polymer.
    Type: Grant
    Filed: March 18, 1985
    Date of Patent: January 13, 1987
    Assignee: Optical Radiation Corporation
    Inventors: Thomas Posin, Daniel D. Lawson
  • Patent number: 4440733
    Abstract: Mixing of carbon in the form of high sulfur coal with sulfuric acid reduces the temperature of sulfuric acid decomposition from 830.degree. C. to between 300.degree. C. and 400.degree. C. The low temperature sulfuric acid decomposition is particularly useful in thermal chemical cycles for splitting water to produce hydrogen. Carbon dioxide is produced as a commercially desirable byproduct. Lowering of the temperature for the sulfuric acid decomposition or oxygen release step simplifies equipment requirements, lowers thermal energy input and reduces corrosion problems presented by sulfuric acid at conventional cracking temperatures. Use of high sulfur coal as the source of carbon for the sulfuric acid decomposition provides an environmentally safe and energy efficient utilization of this normally polluting fuel.
    Type: Grant
    Filed: November 6, 1980
    Date of Patent: April 3, 1984
    Assignee: California Institute of Technology
    Inventors: Daniel D. Lawson, Christopher England
  • Patent number: 4420544
    Abstract: A methanol/air-oxygen fuel cell including an electrode formed by open-ended ion-exchange hollow fibers having a layer of catalyst deposited on the inner surface thereof and a first current collector in contact with the catalyst layer. A second current collector external of said fibers is provided which is immersed along with the hollow fiber electrode in an aqueous electrolyte body. Upon passage of air or oxygen through the hollow fiber electrode and introduction of methanol into the aqueous electrolyte, a steady current output is obtained. Two embodiments of the fuel cell are disclosed. In the first embodiment the second metal electrode is displaced away from the hollow fiber in the electrolyte body while in the second embodiment a spiral-wrap electrode is provided about the outer surface of the hollow fiber electrode.
    Type: Grant
    Filed: October 2, 1981
    Date of Patent: December 13, 1983
    Assignee: California Institute of Technology
    Inventors: Daniel D. Lawson, John D. Ingham
  • Patent number: 4388171
    Abstract: The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.
    Type: Grant
    Filed: October 30, 1981
    Date of Patent: June 14, 1983
    Inventors: James M. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Beggs, William H. Corcoran, William S. Fong, Puvin Pichaichanarong, Paul C. F. Chan, Daniel D. Lawson
  • Patent number: 4334888
    Abstract: A method for enhancing solubilizing mass transport of reactive agents into and out of carbonaceous materials, such as coal. Solubility parameters of mass transfer and solvent media are matched to individual peaks in the solubility parameter spectrum of coals to enhance swelling and/or dissolution.Methanol containing reactive agent carriers are found particularly effective for removing organic sulfur from coals by chlorinolysis.
    Type: Grant
    Filed: April 3, 1981
    Date of Patent: June 15, 1982
    Assignee: California Institute of Technology
    Inventors: William H. Corcoran, Nicholas P. Vasilakos, Daniel D. Lawson
  • Patent number: 4314984
    Abstract: The direct fluid contact heat exchange with H.sub.2 SO.sub.4 at about 330.degree. C. prior to high temperature decomposition at about 830.degree. C. in the oxygen release step of several thermochemical cycles for splitting water into hydrogen and oxygen provides higher heat transfer rates, savings in energy and permits use of cast vessels rather than expensive forged alloy indirect heat exchangers. Among several candidate perfluorocarbon liquids tested, only perfluoropropylene oxide polymers having a degree of polymerization from about 10 to 60 were chemically stable, had low miscibility and vapor pressure when tested with sulfuric acid at temperatures from 300.degree. C. to 400.degree. C.
    Type: Grant
    Filed: April 30, 1980
    Date of Patent: February 9, 1982
    Inventors: Robert A. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Frosch, Daniel D. Lawson, Gene R. Petersen
  • Patent number: 4100331
    Abstract: A gaseous fuel cell is described which includes a pair of electrodes formed by open-ended, ion-exchange hollow fibers, each having a layer of metal catalyst deposited on the inner surface thereof and large surface area current collectors such as braided metal mesh in contact with the metal catalyst layer. A fuel cell results when the electrodes are immersed in electrolyte and electrically connected. As hydrogen and oxygen flow through the bore of the fibers oxidation and reduction reactions develop an electrical potential. Since the hollow fiber configuration provides large electrode area per unit volume and intimate contact between fuel and oxidizer at the interface, and due to the low internal resistance of the electrolyte, high power densities can be obtained.
    Type: Grant
    Filed: February 3, 1977
    Date of Patent: July 11, 1978
    Inventors: James C. Administrator of the National Aeronautics and Space Administration, with respect to an invention of Fletcher, John D. Ingham, Daniel D. Lawson
  • Patent number: 4083765
    Abstract: An improved flow-through electrolytic hygrometer is provided which utilizes a long lasting oxidation-resistant, hollow fiber formed of a persulfonic acid substituted polytetrafluoroethylene having closely spaced noble metal electrodes in contact with the inner and outer surfaces of the fiber. The fiber is disposed within a chamber such that the moisture-bearing gas passes in contact with at least one surface of the fiber. The electrodes are connected in series to a DC voltage supply and an ammeter. As the gas passes through the chamber, moisture absorbed into the wall of the fiber is electrolyzed to hydrogen and oxygen by the closely spaced electrodes. The amount of electricity required for electrolysis is proportional to the absorbed moisture and is observed on the ammeter.
    Type: Grant
    Filed: December 21, 1976
    Date of Patent: April 11, 1978
    Assignee: The United States of America as represented by the Administrator of the National Aeronautics and Space Administration
    Inventor: Daniel D. Lawson