Patents by Inventor Kevin R. Stewart

Kevin R. Stewart 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: 20160020351
    Abstract: A method to optimize electrical energy production from a bifacial module (“BFM”) comprising a plurality of electrically interconnected bifacial photovoltaic cells is disclosed. Applicants' method includes providing a BFM, providing a reflector assembly, positioning the BFM at least about 0.15 meters above the reflector assembly, adjusting an orientation of the BFM using a Tilt Correction Factor, utilizing a minimum spacing between BFMs and further adjusting the orientation using an Azimuth Correction Factor.
    Type: Application
    Filed: July 20, 2015
    Publication date: January 21, 2016
    Inventors: Jose E. Castillo-Aguilella, Paul S. Hauser, Jerome E. Hughes, Kevin R. Stewart
  • Publication number: 20130319524
    Abstract: A solar-energy concentrator and method for collecting sunlight with the concentrator. The concentrator includes a photovoltaic (PV) module having a PV cell and layers containing holographically-defined diffraction gratings that are spatially stacked or multiplexed. Spatial stacking or multiplexing of the gratings is configured to ensure that one grating layer carries another grating layer and that a portion of incident light not diffracted on one grating interacts with and is diffracted by another grating. Light that has interacted with either of the spatially multiplexed gratings is further redirected towards a sunlight collecting surface of the PV cell with the use of TIR reflection at a dielectric boundary of the concentrator.
    Type: Application
    Filed: May 1, 2013
    Publication date: December 5, 2013
    Inventors: Eric D. Aspnes, Jose E. Castillo-Aguilella, Ryan D. Courreges, Paul S. Hauser, Kevin R. Stewart
  • Patent number: 7818566
    Abstract: An apparatus, system, and method are provided for sharing a cached security profile in a database environment. The apparatus, system, and method include a cache module for caching a security profile accessible to primary tasks and secondary tasks. An identification module is provided that distinguishes between primary tasks authorized to refresh the security profile and secondary tasks. A refresh module cooperates with the cache module and identification module to selectively refresh the security profile in response to a refresh request and expiration of the security profile such that an old version of the security profile is retained for use by secondary tasks until an execution window closes.
    Type: Grant
    Filed: August 23, 2007
    Date of Patent: October 19, 2010
    Assignee: International Business Machines Corporation
    Inventors: Michael R. Artobbello, Kevin R. Stewart, Yoshinobu Ueno, Jack C. Yuan
  • Publication number: 20080266087
    Abstract: A security system includes an optical fiber, a plurality of sensors, and a light source, detector, and a controller. The optical fiber and sensors are attached and positioned along a fence. The optical fiber passes through the sensors. The sensors include a hinged striker having a weight that swings under the influence of gravity and is movable in response to vibration of the fence to compress and bend the optical fiber and attenuate transmission of an optical signal through the optical fiber. In another embodiment, an optical fiber cable having a plurality of optical fibers may be employed to define zones and allow determination of intrusion of a particular portion of the fence. In a further embodiment, a ground sensor is disclosed.
    Type: Application
    Filed: February 8, 2006
    Publication date: October 30, 2008
    Inventors: Robert C. Tatar, Kevin R. Stewart
  • Patent number: 7296151
    Abstract: An apparatus, system, and method are provided for sharing a cached security profile in a database environment. The apparatus, system, and method include a cache module for caching a security profile accessible to primary tasks and secondary tasks. An identification module is provided that distinguishes between primary tasks authorized to refresh the security profile and secondary tasks. A refresh module cooperates with the cache module and identification module to selectively refresh the security profile in response to a refresh request and expiration of the security profile such that an old version of the security profile is retained for use by secondary tasks until an execution window closes.
    Type: Grant
    Filed: November 20, 2003
    Date of Patent: November 13, 2007
    Assignee: International Business Machines Corporation
    Inventors: Michael R. Artobello, Kevin R. Stewart, Yoshinobu Ueno, Jack C. Yuan
  • Patent number: 6288206
    Abstract: Chiral organic polymers doped with or appended by nonlinear optical dyes are disclosed. The use of chiral polymers produces a more stable noncentrosymmetric environment for the dye molecules resulting in unexpectedly long relaxation times as compared with previously used organic polymers. In addition, the NLO/chiral polymer materials exhibit high electro-optical coefficients (r33), high nonlinear optical coefficients (d33), improved long-term thermal stability, and at the same time retain the processing advantages associated with organic polymers. Thus, the present NLO/chiral polymer materials are extremely well-suited for use in second-order nonlinear optical and optoelectronics devices.
    Type: Grant
    Filed: November 2, 1999
    Date of Patent: September 11, 2001
    Assignee: Molecular OptoElectronics Corporation
    Inventors: Kevin R. Stewart, Janet L. Gordon, Kwok Pong Chan, David G. Gascoyne, Feng Pan
  • Patent number: 6174987
    Abstract: Linear polycarbonate polymers are disclosed which contain spirobiindanol derivatives regularly alternating in the polymeric chain with derivatives of dihydroxyaromatic compounds, such as biphenols and bisphenols. These clear spirobiindane-dihydroxyaromatic polycarbonates exhibit high glass transition temperatures and exhibit good mechanical and optical properties. In addition, the alternating polycarbonates are thermally stable and remain ductile even at temperatures greater than 150° C. The polycarbonates are therefore useful in high temperature processing and optical applications. The disclosed polycarbonates exhibit indices of refraction that differ sufficiently from those of randomly distributed SBI/BPA polycarbonates to make them useful in the manufacture of optical waveguides.
    Type: Grant
    Filed: August 29, 1997
    Date of Patent: January 16, 2001
    Assignee: Molecular OptoElectronics Corporation
    Inventors: Janet L. Gordon, Kevin R. Stewart
  • Patent number: 5883218
    Abstract: Optically active polycarbonate, polyester, and polyurethane polymers prepared from monomers containing optically pure spirobiindane moieties are disclosed. The chiral spirobiindane polymers are of high molecular weight and exhibit high optical rotations. In addition, the optically active polymers are useful in the fabrication of optoelectronics devices and as polarizing coatings or filters or as polarized lenses.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: March 16, 1999
    Assignee: Molecular OptoElectronics Corporation
    Inventors: Janet L. Gordon, Kevin R. Stewart, Kwok Pong Chan
  • Patent number: 5856422
    Abstract: Optically active poly(aryl)ether polymers prepared from monomers containing optically pure spirobiindane and/or indane moieties are disclosed. The chiral poly(aryl)ether polymers are of high molecular weight and exhibit high optical rotations. In addition, the polyethers are thermally stable at high temperatures and exhibit excellent hydrolytic resistance making them useful in high temperature processing applications, in the fabrication of optoelectronics devices, and as polarizing coatings and filters.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: January 5, 1999
    Assignee: Molecular OptoElectronics Corporation
    Inventors: Kwok Pong Chan, Kevin R. Stewart, Janet L. Gordon
  • Patent number: 5777063
    Abstract: Optically active polycarbonate, polyester, and polyurethane polymers prepared from monomers containing optically pure indane moieties are disclosed. The chiral indane polymers are of high molecular weight and exhibit high optical rotations. In addition, the optically active polymers are useful in the fabrication of optoelectronics devices and as polarizing coatings or filters or as polarized lenses.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: July 7, 1998
    Assignee: Molecular OptoElectronics Corporation
    Inventors: Janet L. Gordon, Kevin R. Stewart, Kwok Pong Chan
  • Patent number: 5543960
    Abstract: Apparatus for the generation of high energy terahertz radiation is presented and comprises laser means effective to produce subpicosecond optical pulses and a mosaic comprising a plurality of planar electro-optic crystals fastened together edge to edge in the form of a grid. The electro-optic crystals are in optical communication with the subpicosecond optical pulses, and behave as a single large electro-optic crystal, producing high energy terahertz radiation by way of optical rectification.
    Type: Grant
    Filed: May 11, 1995
    Date of Patent: August 6, 1996
    Assignee: The Regents of the University of California
    Inventors: Timothy J. Carrig, Antoinette J. Taylor, Kevin R. Stewart
  • Patent number: 5360911
    Abstract: A novel process is disclosed for producing stilbazolium salts. Said novel process employs a heterocyclic amine catalyst, such as pyrrolidine, an alkylated pyridine salt and a substituted benzaldehyde which unexpectedly results in increased reaction rates and product yields.
    Type: Grant
    Filed: June 17, 1993
    Date of Patent: November 1, 1994
    Assignee: General Electric Company
    Inventors: Eugene P. Boden, Peter D. Phelps, Kevin R. Stewart
  • Patent number: 5332827
    Abstract: Deuterated organic salts useful in nonlinear optical applications are disclosed herein. More particularly, optoelectronic devices and systems are prepared from said deuterated organic salts and the preferred salt is perdeuterated 4'-dimethylamino-4-methylstilbazolium p-toluenesulfonate.
    Type: Grant
    Filed: August 23, 1993
    Date of Patent: July 26, 1994
    Assignee: General Electric Company
    Inventors: Kevin R. Stewart, Eugene P. Boden, Christopher P. Yakymyshyn
  • Patent number: 5323482
    Abstract: Deuterated organic salts useful in nonlinear optical applications are disclosed herein. More particularly, optoelectronic devices and systems are prepared from said deuterated organic salts and the preferred salt is perdeuterated 4'-dimethylamino-4-methylstilbazolium p-toluenesulfonate.
    Type: Grant
    Filed: May 27, 1993
    Date of Patent: June 21, 1994
    Assignee: General Electric Company
    Inventors: Kevin R. Stewart, Eugene P. Boden, Christopher P. Yakymyshyn
  • Patent number: 5292888
    Abstract: Stilbazolium salts that retain high second harmonic generation properties as well as high melting points are disclosed herein. More particularly, novel 4'-dimethylamino-N-methylstilbazolium cyclopentanesulfonate and homologs thereof which are expected to be useful in optoelectric devices and systems are disclosed.
    Type: Grant
    Filed: June 28, 1993
    Date of Patent: March 8, 1994
    Assignee: General Electric Company
    Inventor: Kevin R. Stewart
  • Patent number: 5194984
    Abstract: 4'-Dimethylamino-4-methylstilbazolium methanesulfonate is prepared by the reaction of methyl methanesulfonate with 4-picoline followed by condensation with p-dimethylaminobenzaldehyde. Its hydrated form has second harmonic generation optical properties, but this is not true of the anhydrous form. Thus, the hydrated form is useful in the production of optical waveguides, spatial light modulators and the like.
    Type: Grant
    Filed: June 10, 1991
    Date of Patent: March 16, 1993
    Assignee: General Electric Company
    Inventors: Eugene P. Boden, Peter D. Phelps, Christopher P. Yakymyshyn, Kevin R. Stewart
  • Patent number: 5094553
    Abstract: Optical waveguides comprise as core and cladding materials a chemical compound in two different crystalline forms with different indices of refraction. Preferably, the non-linear form is anhydrous and the linear form is a hydrate thereof, whereupon the core material can be prepared by selective heating of the cladding material as by a laser beam. A preferred compound is 4'-dimethylamino-4-methylstilbazolium p-toluenesulfonate.
    Type: Grant
    Filed: November 28, 1990
    Date of Patent: March 10, 1992
    Assignee: General Electric Company
    Inventors: Christopher P. Yakymyshyn, Eugene P. Boden, Peter D. Phelps, Kevin R. Stewart
  • Patent number: 5087692
    Abstract: Cyclic polycarbonate oligomers are converted to linear polycarbonates by the catalytic action of a monobasic metal salicylate. The polymerization reaction takes place only at relatively high temperatures, typically above about 220.degree. C., and rapidly only at temperatures above about 250.degree. C., and is therefore particularly useful in such operations as resin transfer molding. The catalyst may be coated on a fibrous reinforcing material used for composite formation.
    Type: Grant
    Filed: June 7, 1990
    Date of Patent: February 11, 1992
    Assignee: General Electric Company
    Inventors: Kevin R. Stewart, Andrew J. Salem
  • Patent number: 4927911
    Abstract: Cyclic polycarbonate oligomers are converted to linear polycarbonates by the catalytic action of a zwitterionic compound containing positively charged nitrogen and negatively charged oxygen. The polymerization reaction is slow, and therefore particularly useful in such operations as resin transfer molding.
    Type: Grant
    Filed: February 22, 1989
    Date of Patent: May 22, 1990
    Assignee: General Electric Company
    Inventor: Kevin R. Stewart
  • Patent number: 4927910
    Abstract: Cyclic polycarbonate oligomers are converted to linear polycarbonates by the catalytic action of an aryl tetrahydropyranyl ether. The polymerization reaction is slow, and therefore particularly useful in such operations as resin transfer molding.
    Type: Grant
    Filed: February 22, 1989
    Date of Patent: May 22, 1990
    Assignee: General Electric Company
    Inventor: Kevin R. Stewart