Patents by Inventor Tjaart Andries Du Plessis

Tjaart Andries Du Plessis 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: 7762019
    Abstract: This invention relates to a plant protective cover of a translucent polymeric material including at least one transmission spectrum modifier for minimizing the transmission in the ultraviolet range up to 350 nm; and for adjusting the transmission in the visible light range between 350 nm and 750 nm in accordance with photosynthetic and photomorphogenic requirements of plants to be cultivated underneath the plant protective cover, to enhance the growth conditions of such plants. The cover further includes a transmission spectrum modifier for minimizing the transmission in the infrared range above 750 nm. The transmission in the visible light range between 350 nm and 750 nm is adjusted by decreasing the transmitted green and yellow wavelengths and by changing the ratio of blue to red wavelengths transmitted towards a 2:3 ratio. The cover optimises growing conditions for plants cultivated underneath the cover thus providing relatively enhanced plant growth and performance.
    Type: Grant
    Filed: March 4, 2004
    Date of Patent: July 27, 2010
    Assignee: North-West University
    Inventors: Leon Van Rensburg, Tjaart Andries Du Plessis, Horst Seute
  • Patent number: 7094472
    Abstract: The invention relates to ethylene polymers that are modified by ionizing radiation, prior to article formation, at a temperature less than the crystalline melt temperature and preferably under ambient atmosphere, as well as articles made from said polymers. The irradiated ethylene polymers exhibit enhanced melt strength, tensile strength, impact resistance, tear strength, adhesion to polar substances and thermal stability, decreased elongation, and lower melt flow index, but are easily processed and converted into and onto articles by conventional technologies including injection molding, extrusion, film and bottle blowing and powder coating.
    Type: Grant
    Filed: October 17, 2003
    Date of Patent: August 22, 2006
    Assignees: Ion Beam Applications, S.A., Gammatron Pty LTD
    Inventors: Tjaart Andries Du Plessis, Song Cheng, Horst Seute
  • Patent number: 6841644
    Abstract: Disclosed are modified naturally occurring biocompatible biopolymers of plant and animal origin made by subjecting same to ionizing radiation in the presence of a mediating gas, typically acetylene to enable one to selectively enhance and modify one or more of the physiochemical properties of the starting materials which have a wide range of uses in medicine, food technology and other industrial applications. Notwithstanding the modifications, the biocompatibility of the biopolymer remains unchanged and no new or additional functional groups are introduced into the starting biopolymer.
    Type: Grant
    Filed: March 28, 2003
    Date of Patent: January 11, 2005
    Assignee: Phillips Hydrocolloids Research Limited
    Inventors: Glyn Owen Phillips, Tjaart Andries Du Plessis, Saphwan Al-Assaf, Peter Anthony Williams
  • Publication number: 20040132854
    Abstract: The invention relates to ethylene polymers that are modified by ionizing radiation, prior to article formation, at a temperature less than the crystalline melt temperature and preferably under ambient atmosphere, as well as articles made from said polymers. The irradiated ethylene polymers exhibit enhanced melt strength, tensile strength, impact resistance, tear strength, adhesion to polar substances and thermal stability, decreased elongation, and lower melt flow index, but are easily processed and converted into and onto articles by conventional technologies including injection molding, extrusion, film and bottle blowing and powder coating.
    Type: Application
    Filed: October 17, 2003
    Publication date: July 8, 2004
    Inventors: Tjaart Andries Du Plessis, Song Cheng, Horst Seute
  • Publication number: 20040059097
    Abstract: Disclosed are modified naturally occurring biocompatible biopolymers of plant and animal origin made by subjecting same to ionizing radiation in the presence of a mediating gas, typically acetylene to enable one to selectively enhance and modify one or more of the physiochemical properties of the starting materials which have a wide range of uses in medicine, food technology and other industrial applications. Notwithstanding the modifications, the biocompatibility of the biopolymer remains unchanged and no new or additional functional groups are introduced into the starting biopolymer.
    Type: Application
    Filed: March 28, 2003
    Publication date: March 25, 2004
    Inventors: Glyn Owen Phillips, Tjaart Andries Du Plessis, Saphwan Al-Assaf, Peter Anthony Williams
  • Patent number: 6610810
    Abstract: Disclosed is a method for modifying naturally occuring biocompatible biopolymers of plant and animal origin by subjecting same to ionizing radiation in the presence of a mediating gas, typically acetylene to enable one to selectively enhance and modify one or more of the physiochemical propserties of the starting materials which have a wide range of uses in medicine, food technology and other industrial applications. Notwithstanding the modifications, the biocompatibility of the biopolymer remains unchanged and no new or additional functional groups are introduced into the starting biopolymer.
    Type: Grant
    Filed: March 13, 2001
    Date of Patent: August 26, 2003
    Inventors: Glyn Owen Phillips, Tjaart Andries Du Plessis, Saphwan Al-Assaf, Peter Anthony Williams