Patents by Inventor Joseph S. Chang

Joseph S. Chang 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).

  • Publication number: 20240141130
    Abstract: A tandem polyolefin depolymerization-metathesis process and system for converting polymer waste to smaller hydrocarbons, specifically liquid and gaseous products, which subsequently can be modified and used as feeds or co-feeds for making circular products such as circular ethylene and polyethylene. Specifically, the disclosed processes include a tandem depolymerization process step followed by a metathesis process to provide a effluent that can be separated, further processed with a subsequent depolymerization step, or both. The effluents can be supplied to downstream processing units such as a steam cracker or AROMAX® unit thereby providing an efficient method for converting polymer waste into useful circular products. Therefore, these processes and systems can expand the number of usable plastic waste streams and improve the economics of plastic waste recycling.
    Type: Application
    Filed: November 1, 2022
    Publication date: May 2, 2024
    Applicant: Chevron Phillips Chemical Company LP
    Inventors: Cori A. Demmelmaier-Chang, Mark L. Hlavinka, Orson Sydora, Sikander Hakim, Jeffery Gee, Joseph Bergmeister, Gabriela Alvez, Steven S. Lim
  • Patent number: 5631965
    Abstract: An active in the ear hearing protector having an ear piece (13) and a casing (12) attachable to the ear piece, the ear piece being positionable in the ear canal of a user so as to peripherally acoustically seal the ear canal and such that the attached casing (12) is positioned externally of the ear canal. The casing (12) incorporates a microphone (14) for receiving external acoustic sound signal and a signal processing circuit (15) for receiving electrical signal from the microphone and correspondingly causing a loudspeaker (16) in the casing to generate sound signal for direction down a tube (34) extending through the ear piece to be transmitted to the ear canal. The electrical circuit (15) is arranged to limit the electrical signal delivered to drive the loudspeaker whereby to limit the sound pressure of sound signal delivered from the loudspeaker to the ear canal via the tube (34).
    Type: Grant
    Filed: February 15, 1995
    Date of Patent: May 20, 1997
    Inventors: Joseph S. Chang, Yit C. Tong
  • Patent number: 5182521
    Abstract: A time-multiplexed switched capacitor circuit in which certain capacitors are shared during local time periods of a global time period to allow the total capacitance of the circuit to be reduced. Corresponding savings in chip area in an integrated circuit implementation and component savings in a discrete implementation may be achieved. The invention is particularly applicable to a multiplexed circuit comprising an array of capacitors including first and second common capacitors and first and second pluralities of capacitors. The capacitors may be switched into and out of the multiplexed circuit during different local time periods. The first common capacitor may be switched into the circuit when any one of the first plurality of capacitors is involved in the operation of the multiplexed circuit thus reducing the size of that one capacitor of the first plurality of capacitors.
    Type: Grant
    Filed: October 23, 1991
    Date of Patent: January 26, 1993
    Assignee: The University of Melbourne
    Inventors: Joseph S. Chang, Yit C. Tong