Patents by Inventor Michael Ghebrebrhan
Michael Ghebrebrhan 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).
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Patent number: 11822105Abstract: The disclosed subject matter relates to relate to fibers, textiles, fabrics, clothing and methods that are retroreflective including fibers having a hollow sheath that is filled with retroreflective particles.Type: GrantFiled: December 7, 2021Date of Patent: November 21, 2023Assignee: The Government of the United States, as represented by the Secretary of the ArmyInventors: Michael Ghebrebrhan, Eric Wetzel
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Patent number: 11123937Abstract: Disclosed is a retro-reflective thread 100 including an internal section 10; a plurality of fibers 12, each fiber comprising a respective longitudinal axis and a respective surface and each fiber comprising a first material that is at least partially optically transmissive, and wherein said plurality of fibers are configured with their respective longitudinal axes substantially co-linearly aligned with one another and said plurality of fibers are interconnected in series around said internal section and wherein a first part 12b of said respective surface of each of said plurality of fibers faces into said internal section; and a reflective material 14 provided on said first part of said respective surface of each of said plurality of fibers.Type: GrantFiled: August 20, 2019Date of Patent: September 21, 2021Assignee: U.S. Government as Represented by the Secretary of the ArmyInventors: Michael Ghebrebrhan, Landa Hoke
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Patent number: 10427367Abstract: Disclosed is a retro-reflective thread 100 including an internal section 10; a plurality of fibers 12, each fiber comprising a respective longitudinal axis and a respective surface and each fiber comprising a first material that is at least partially optically transmissive, and wherein said plurality of fibers are configured with their respective longitudinal axes substantially co-linearly aligned with one another and said plurality of fibers are interconnected in series around said internal section and wherein a first part 12b of said respective surface of each of said plurality of fibers faces into said internal section; and a reflective material 14 provided on said first part of said respective surface of each of said plurality of fibers.Type: GrantFiled: February 24, 2016Date of Patent: October 1, 2019Assignee: U.S. Government as Represented by the Secretary of the ArmyInventors: Michael Ghebrebrhan, Landa Hoke
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Patent number: 9116537Abstract: Inventive systems and methods for the generation of energy using thermophotovoltaic cells are described. Also described are systems and methods for selectively emitting electromagnetic radiation from an emitter for use in thermophotovoltaic energy generation systems. In at least some of the inventive energy generation systems and methods, a voltage applied to the thermophotovoltaic cell (e.g., to enhance the power produced by the cell) can be adjusted to enhance system performance. Certain embodiments of the systems and methods described herein can be used to generate energy relatively efficiently.Type: GrantFiled: May 20, 2011Date of Patent: August 25, 2015Assignee: Massachusetts Institute of TechnologyInventors: Ivan Celanovic, Walker Chan, Peter Bermel, Adrian Y. X. Yeng, Christopher Marton, Michael Ghebrebrhan, Mohammad Araghchini, Klavs F. Jensen, Marin Soljacic, John D. Joannopoulos, Steven G. Johnson, Robert Pilawa-Podgurski, Peter Fisher
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Patent number: 9057830Abstract: The present invention provides systems, articles, and methods for discriminating electromagnetic radiation based upon the angle of incidence of the electromagnetic radiation. In some cases, the materials and systems described herein can be capable of inhibiting reflection of electromagnetic radiation (e.g., the materials and systems can be capable of transmitting and/or absorbing electromagnetic radiation) within a given range of angles of incidence at a first incident surface, while substantially reflecting electromagnetic radiation outside the range of angles of incidence at a second incident surface (which can be the same as or different from the first incident surface). A photonic material comprising a plurality of periodically occurring separate domains can be used, in some cases, to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation, based upon the angle of incidence.Type: GrantFiled: July 19, 2011Date of Patent: June 16, 2015Assignee: Massachusetts Institute of TechnologyInventors: Rafif E. Hamam, Peter Bermel, Ivan Celanovic, Marin Soljacic, Adrian Y. X. Yeng, Michael Ghebrebrhan, John D. Joannopoulos
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Publication number: 20120037217Abstract: The present invention provides systems, articles, and methods for discriminating electromagnetic radiation based upon the angle of incidence of the electromagnetic radiation. In some cases, the materials and systems described herein can be capable of inhibiting reflection of electromagnetic radiation (e.g., the materials and systems can be capable of transmitting and/or absorbing electromagnetic radiation) within a given range of angles of incidence at a first incident surface, while substantially reflecting electromagnetic radiation outside the range of angles of incidence at a second incident surface (which can be the same as or different from the first incident surface). A photonic material comprising a plurality of periodically occurring separate domains can be used, in some cases, to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation, based upon the angle of incidence.Type: ApplicationFiled: July 19, 2011Publication date: February 16, 2012Applicant: Massachusetts Institute of TechnologyInventors: Rafif E. Hamam, Peter Bermel, Ivan Celanovic, Marin Soljacic, Adrian Y.X. Yeng, Michael Ghebrebrhan, John D. Joannopoulos
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Publication number: 20110284059Abstract: Inventive systems and methods for the generation of energy using thermophotovoltaic cells are described. Also described are systems and methods for selectively emitting electromagnetic radiation from an emitter for use in thermophotovoltaic energy generation systems. In at least some of the inventive energy generation systems and methods, a voltage applied to the thermophotovoltaic cell (e.g., to enhance the power produced by the cell) can be adjusted to enhance system performance. Certain embodiments of the systems and methods described herein can be used to generate energy relatively efficiently.Type: ApplicationFiled: May 20, 2011Publication date: November 24, 2011Applicant: Massachusetts Institute of TechnologyInventors: Ivan Celanovic, Walker Chan, Peter Bermel, Adrian Y.X. Yeng, Christopher Marton, Michael Ghebrebrhan, Mohammad Araghchini, Klavs F. Jensen, Marin Soljacic, John D. Joannopoulos, Steven G. Johnson, Robert Pilawa-Podgurski, Peter Fisher
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Publication number: 20100258174Abstract: A solar cell includes a thin film photovoltaic material structure used in absorbing light of a selective bandwidth. A multitude of dielectric front coatings are positioned on the thin film photovoltaic material structure so as to maximize admittance over the selected bandwidth. The thicknesses and indices of each of the front coatings are chosen by a global-optimization procedure to maximize the short-circuit current of the solar cell.Type: ApplicationFiled: April 14, 2009Publication date: October 14, 2010Inventors: Michael Ghebrebrhan, Peter Bermel, Yehuda Avniel, John D. Joannopoulos, Steven G. Johnson
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Patent number: RE47157Abstract: The present invention provides systems, articles, and methods for discriminating electromagnetic radiation based upon the angle of incidence of the electromagnetic radiation. In some cases, the materials and systems described herein can be capable of inhibiting reflection of electromagnetic radiation (e.g., the materials and systems can be capable of transmitting and/or absorbing electromagnetic radiation) within a given range of angles of incidence at a first incident surface, while substantially reflecting electromagnetic radiation outside the range of angles of incidence at a second incident surface (which can be the same as or different from the first incident surface). A photonic material comprising a plurality of periodically occurring separate domains can be used, in some cases, to selectively transmit and/or selectively absorb one portion of incoming electromagnetic radiation while reflecting another portion of incoming electromagnetic radiation, based upon the angle of incidence.Type: GrantFiled: June 12, 2017Date of Patent: December 11, 2018Assignee: Massachusetts Institute of TechnologyInventors: Rafif E. Hamam, Peter Bermel, Ivan Celanovic, Marin Soljacic, Adrian Y. X. Yeng, Michael Ghebrebrhan, John D. Joannopoulos