Patents by Inventor Chilengi P. Madhusudhan

Chilengi P. Madhusudhan 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).

  • Ambient ether vapor testing apparatus and method
    Patent number: 5168746
    Abstract: A portion of the ambient air, including the selected vapor such as the ether vapor fraction, is first cryogenically liquefied for concentration in a collecting vessel (12). Thereafter, the concentrated liquefied fraction is boiled off and passed through gas chromatography column (34) to separate the fractions in the vapor stream. The selected vapor fraction is eluted at the temperature, and its concentration is detected by thermal conductivity detector (42) so that the concentration of the selected vapor in the environment is signaled.
    Type: Grant
    Filed: June 3, 1991
    Date of Patent: December 8, 1992
    Assignee: Hughes Aircraft Company
    Inventors: Chilengi P. Madhusudhan, Joaquin M. Otero
  • Methods for removing stringers appearing in copper-containing multi-layer printed wiring boards
    Patent number: 5049234
    Abstract: Copper-containing multilayer substrates are etched, and stringers formed in the plated through-holes in these substrates are simultaneously removed by treatment with an aqueous composition including about 37% by weight hydrofluoric acid and about 16% by weight nitric acid. The same aqueous composition can be used to remove stringers formed during treatment of such substrates with other etchants.
    Type: Grant
    Filed: February 8, 1988
    Date of Patent: September 17, 1991
    Assignee: Hughes Aircraft Company
    Inventor: Chilengi P. Madhusudhan
  • Low temperature thermoelectrochemical system and method
    Patent number: 4738904
    Abstract: A thermoelectrochemical system in which a continuous electrical current is generated from a heat input below about 250.degree. C. A hydrogen ion reacting cathode is immersed in a chosen Bronsted acid and a hydrogen ion reacting anode is immersed in a chosen Bronsted base. Reactants consumed at the electrodes during the electrochemical reaction are directly regenerated thermally below about 250.degree. C. and recycled to the electrodes to provide continuous operation of the system.
    Type: Grant
    Filed: October 14, 1986
    Date of Patent: April 19, 1988
    Assignee: Hughes Aircraft Company
    Inventors: Frank A. Ludwig, Carl W. Townsend, Chilengi P. Madhusudhan