Patents by Inventor Vilupanur Ravi
Vilupanur Ravi 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: 11731196Abstract: Systems and methods of additively manufacturing multi-material electromagnetic shields are described. Additive manufacturing processes use co-deposition to incorporate multiple materials and/or microstructures selected to achieve specified shield magnetic properties. Geometrically complex shields can be manufactured with alternating shielding materials optimized for the end use application. The microstructures of the printed shields can be tuned by optimizing the print parameters.Type: GrantFiled: August 5, 2021Date of Patent: August 22, 2023Assignee: California Institute of TechnologyInventors: Samad A. Firdosy, Robert P. Dillon, Nicholas E. Ury, Katherine Dang, Joshua Berman, Pablo Narvaez, Vilupanur A. Ravi, John Paul Castelo Borgonia, Joelle T. Cooperrider, Bryan W. McEnerney, Andrew A. Shapiro-Scharlotta
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Publication number: 20220203442Abstract: Systems and methods of additively manufacturing multi-material electromagnetic shields are described. Additive manufacturing processes use co-deposition to incorporate multiple materials and/or microstructures selected to achieve specified shield magnetic properties. Geometrically complex shields can be manufactured with alternating shielding materials optimized for the end use application. The microstructures of the printed shields can be tuned by optimizing the print parameters.Type: ApplicationFiled: August 5, 2021Publication date: June 30, 2022Applicant: California Institute of TechnologyInventors: Samad A. Firdosy, Robert P. Dillon, Nicholas E. Ury, Katherine Dang, Joshua Berman, Pablo Narvaez, Vilupanur A. Ravi, John Paul Castelo Borgonia, Joelle T. Cooperrider, Bryan W. McEnerney, Andrew A. Shapiro-Scharlotta
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Patent number: 10017687Abstract: The present invention provides a method of preparing a proppant material by heating a reaction mixture comprising a plurality of oxides in a reactive atmosphere to a temperature above the melting point of the reaction mixture to form a melt, and then allowing the melt to solidify in a mold in the form of spherical particles. The present invention also provides a method of preparing a proppant material by heating a reaction mixture comprising a plurality of oxides and one or more additives in a reactive atmosphere to a temperature below the melting point of the reaction mixture to form a powder including one or more reaction products, and then processing the powder to form spherical particles. The present invention also provides a proppant material including spherical particles characterized by a specific gravity of about 1.0 to 3.0 and a crush strength of at least about 10,000 psi.Type: GrantFiled: May 14, 2015Date of Patent: July 10, 2018Assignee: CALIFORNIA INSTITUTE OF TECHNOLOGYInventors: Vilupanur A. Ravi, Samad A. Firdosy, Jean-Pierre Fleurial, Sabah K. Bux, Andrew Kindler
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Patent number: 9869629Abstract: The present invention discloses a method and system for conducting high temperature corrosion tests on metallic alloys without the need for extensive laboratory equipment and attendant safety measures through the use of a two-compartment ampoule where a vestibule connects these two compartments. A pre-selected mixture of salts is placed in one compartment in order to generate a specific partial pressure of halogen gas; and a metallic alloy is placed in the other compartment. The ampoule is then heated to a pre-determined temperature and held at this temperature for a pre-determined time period. A halogen gas of a specific partial pressure is thereby generated from the mixture of salts which comes into contact with the metallic alloy. Because the ampoule creates a sealed environment, the metallic alloy is under constant halogenation during the pre-determined time period. The metallic alloy is removed for examination when the pre-determined time period expires.Type: GrantFiled: February 17, 2017Date of Patent: January 16, 2018Assignee: Cal Poly Pomona Foundation, Inc.Inventors: Vilupanur A Ravi, Juan Carlos Nava, Shahan Kasnakjian
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Patent number: 9722163Abstract: A thermoelectric power generation device is disclosed using one or more mechanically compliant and thermally and electrically conductive layers at the thermoelectric material interfaces to accommodate high temperature differentials and stresses induced thereby. The compliant material may be metal foam or metal graphite composite (e.g. using nickel) and is particularly beneficial in high temperature thermoelectric generators employing Zintl thermoelectric materials. The compliant material may be disposed between the thermoelectric segments of the device or between a thermoelectric segment and the hot or cold side interconnect of the device.Type: GrantFiled: June 7, 2013Date of Patent: August 1, 2017Assignee: California Institute of TechnologyInventors: Samad A. Firdosy, Billy Chun-Yip Li, Vilupanur A. Ravi, Jean-Pierre Fleurial, Thierry Caillat, Harut Anjunyan
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Patent number: 9640746Abstract: The present invention provides a composite thermoelectric material. The composite thermoelectric material can include a semiconductor material comprising a rare earth metal. The atomic percent of the rare earth metal in the semiconductor material can be at least about 20%. The composite thermoelectric material can further include a metal forming metallic inclusions distributed throughout the semiconductor material. The present invention also provides a method of forming this composite thermoelectric material.Type: GrantFiled: January 22, 2014Date of Patent: May 2, 2017Assignee: California Institute of TechnologyInventors: James M. Ma, Sabah K. Bux, Jean-Pierre Fleurial, Vilupanur A. Ravi, Samad A. Firdosy, Kurt Star, Richard B. Kaner
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Publication number: 20170077379Abstract: A thermoelectric power generation technique is disclosed using one or more mechanically compliant and thermally and electrically conductive layers at the thermoelectric material interfaces to accommodate high temperature differentials and stresses induced thereby. The compliant material may be metal foam or metal graphite composite (e.g. using nickel) and is particularly beneficial in high temperature thermoelectric generators employing Zintl thermoelectric materials. The compliant material may be disposed between the thermoelectric segments of the device or between a thermoelectric segment and the hot or cold side interconnect of the device.Type: ApplicationFiled: November 21, 2016Publication date: March 16, 2017Applicant: California Institute of TechnologyInventors: Samad A. Firdosy, Billy Chun-Yip Li, Vilupanur A. Ravi, Jean-Pierre Fleurial, Thierry Caillat, Harut Anjunyan
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Publication number: 20170066962Abstract: The disclosure herein includes methods of preparing ceramic beads, useful as proppant materials, by mixing ceramic precursors, such as slag, fly ash, or aluminum dross, forming bead precursors from the mixture, and heating the bead precursors to drive a chemical reaction between the ceramic precursors to form the ceramic beads. The resultant ceramic beads may be generally spherical particles that are characterized by diameters of about 0.1 to 2 mm, a diametral strength of at least about 100 MPa, and a specific gravity of about 1.0 to 3.0. A coating process may optionally be used to increase a diametral strength of a proppant material. A sieving process may optionally be used to obtain a smaller range of sizes of proppant materials.Type: ApplicationFiled: September 9, 2016Publication date: March 9, 2017Inventors: Vilupanur A. Ravi, Samad A. Firdosy, Sabah K. Bux, Jean-Pierre Fleurial, Shiao-Pin S. Yen, Andrew Kindler, Su C. Chi, Margie L. Homer, Bryan W. McEnerney, Pandurang Kulkarni, Desikan Sundararajan
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Publication number: 20160304993Abstract: The present application relates to systems and methods of producing ductile nickel-based austenitic alloy coatings. The methods may include using low levels of aluminum to form protective coatings, while retaining ductility. The method can include preselecting a desired thickness of coating to maximize the desired level of aluminum and ductility.Type: ApplicationFiled: November 4, 2015Publication date: October 20, 2016Inventors: Vilupanur A. Ravi, George Lai, Juan Carlos Nava
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Publication number: 20160111619Abstract: The present invention provides a composite thermoelectric material. The composite thermoelectric material can include a semiconductor material comprising a rare earth metal. The atomic percent of the rare earth metal in the semiconductor material can be at least about 20%. The composite thermoelectric material can further include a metal forming metallic inclusions distributed throughout the semiconductor material. The present invention also provides a method of forming this composite thermoelectric material.Type: ApplicationFiled: January 22, 2014Publication date: April 21, 2016Applicant: CALIFORNIA INSTITUTE OF TECHNOLOGYInventors: James M. Ma, Sabah K. Bux, Jean-Pierre Fleurial, Vilupanur A. Ravi, Samad A. Firdosy, Kurt Star, Richard B. Kaner
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Publication number: 20150357541Abstract: A thermoelectric power generation device is disclosed using one or more mechanically compliant and thermally and electrically conductive layers at the thermoelectric material interfaces to accommodate high temperature differentials and stresses induced thereby. The compliant material may be metal foam or metal graphite composite (e.g. using nickel) and is particularly beneficial in high temperature thermoelectric generators employing Zintl thermoelectric materials. The compliant material may be disposed between the thermoelectric segments of the device or between a thermoelectric segment and the hot or cold side interconnect of the device.Type: ApplicationFiled: June 7, 2013Publication date: December 10, 2015Applicant: CALIFORNIA INSTITUTE OF TECHNOLOGYInventors: Samad A. Firdosy, Billy Chun-Yip Li, Vilupanur A. Ravi, Jean-Pierre Fleurial, Thierry Caillat, Harut Anjunyan
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Publication number: 20150329769Abstract: The present invention provides a method of preparing a proppant material by heating a reaction mixture comprising a plurality of oxides in a reactive atmosphere to a temperature above the melting point of the reaction mixture to form a melt, and then allowing the melt to solidify in a mold in the form of spherical particles. The present invention also provides a method of preparing a proppant material by heating a reaction mixture comprising a plurality of oxides and one or more additives in a reactive atmosphere to a temperature below the melting point of the reaction mixture to form a powder including one or more reaction products, and then processing the powder to form spherical particles. The present invention also provides a proppant material including spherical particles characterized by a specific gravity of about 1.0 to 3.0 and a crush strength of at least about 10,000 psi.Type: ApplicationFiled: May 14, 2015Publication date: November 19, 2015Inventors: Vilupanur A. Ravi, Samad A. Firdosy, Jean-Pierre Fleurial, Sabah K. Bux, Andrew Kindler
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Publication number: 20100307551Abstract: The present invention relates to a high-temperature thermoelectric couple and the method for making the same. The method requires a very small number of fabrication steps. It includes an act of fabricating an n-type leg that, in a stacked configuration, includes a low electrical contact resistance metallization foil that is connected to each of the two sides of Lanthanum Telluride via a thin metallic adhesion layer. Additionally, a p-type leg is fabricated that, in a stacked configuration, includes a low electrical contact resistance metallization foil that is connected to each of the two sides of 14-1-11 Zintl. Finally, CTE-matched, low electrical and thermal resistance plate interconnects are used for each of the two legs to interface with the heat source and heat sink and form an electrical connection.Type: ApplicationFiled: May 27, 2010Publication date: December 9, 2010Applicant: California Institute of TechnologyInventors: Vilupanur A. Ravi, Billy Chun-Yip Li, Jean-Pierre Fleurial, Kurt Star
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Publication number: 20100243018Abstract: A thermoelectric power generation device using molybdenum metallization to a Zintl thermoelectric material in a thermoelectric power generation device operating at high temperature, e.g. at or above 1000° C., is disclosed. The Zintl thermoelectric material may comprise Yb14MnSb11. A thin molybdenum metallization layer of approximately 5 microns or less may be employed. The thin molybdenum layer may be applied in a foil under high pressure, e.g. 1800 psi, at high temperature, e.g. 1000° C. The metallization layer may then be bonded or brazed to other components, such as heat collectors or current carrying electrodes, of the thermoelectric power generation device.Type: ApplicationFiled: March 29, 2010Publication date: September 30, 2010Applicant: California Institute of TechnologyInventors: Billy Chun-Yip Li, Erik J. Brandon, Vilupanur A. Ravi, Thierry Caillat, Richard C. Ewell, Samad A. Firdosy, Jeff S. Sakamoto
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Publication number: 20070240750Abstract: A thermoelectric having self-assembled structures, where the structures may be lamellae or dendrites. For some embodiments, the self-assembled structures are obtained by melting a mixture of Pb, Te, and Sb; cooling; and then annealing. During this process, a metastable alloy is formed, which decomposes into lamellae structures of PbTe and Sb2Te3. Other embodiments are described and claimed.Type: ApplicationFiled: March 5, 2007Publication date: October 18, 2007Inventors: G. Jeffrey Snyder, Teruyuki Ikeda, Sossina Haile, Vilupanur Ravi
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Publication number: 20030124009Abstract: Hydrophilic polymer actuators for an implantable device and methods of forming such actuators are provided, wherein the hydrophilic polymer actuators are actuated by the hydration and dehydration of a hydrophilic polymer material.Type: ApplicationFiled: October 23, 2002Publication date: July 3, 2003Inventors: Vilupanur A. Ravi, Morteza Gharib, Benjamin A. Welander
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Patent number: 5518061Abstract: The present invention relates to modifying the properties of a metal matrix composite body by a post formation process treatment and/or a substantially contiguous modification treatment. The post formation process treatment may be applicable to a variety of metal matrix composite bodies produced by various techniques, and is particularly applicable to modifying the properties of a metal matrix composite body produced by a spontaneous infiltration technique. The substantially contiguous modification process may also be used primarily in conjunction with metal matrix composite bodies produced according to a spontaneous infiltration technique. Particularly, at least a portion of the matrix metal of the metal matrix composite body and/or the filler material of the metal matrix composite body is modified or altered during and/or after the formation process.Type: GrantFiled: February 22, 1994Date of Patent: May 21, 1996Assignee: Lanxide Technology Company, LPInventors: Marc S. Newkirk, Andrew W. Urquhart, Michael K. Aghajanian, Mark G. Mortenson, Vilupanur A. Ravi, Alan S. Nagelberg
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Patent number: 5439744Abstract: This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies.Type: GrantFiled: February 25, 1993Date of Patent: August 8, 1995Assignee: Lanxide Technology Company, LPInventors: Terry D. Claar, Vilupanur A. Ravi, Philip J. Roach
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Patent number: 5403790Abstract: This invention relates generally to a novel method of manufacturing a composite body. More particularly, the present invention relates to a method for modifying the resultant properties of a composite body, by, for example, minimizing the amount of porosity present in the composite body. Moreover, additives, whether used alone or in combination, (1) can be admixed with the permeable mass, (2) can be mixed or alloyed with the parent metal, (3) can be placed at an interface between the parent metal and the preform or mass of filler material, (4) or any combination of the aforementioned methods, to modify properties of the resultant composite body. Particularly, additives such as VC, NbC, WC, W.sub.2 B.sub.5, TaC, ZrC, ZrB.sub.2, SiB.sub.6, SiC, MgO, Al.sub.2 O.sub.3, ZrO.sub.2, CeO.sub.2, Y.sub.2 O.sub.3, La.sub.2 O.sub.3, MgAl.sub.2 O.sub.4, HfO.sub.2, ZrSiO.sub.4, Yb.sub.2 O.sub.3 and Mo.sub.2 B.sub.Type: GrantFiled: January 11, 1993Date of Patent: April 4, 1995Assignee: Lanxide Technology Company, LPInventors: Terry D. Claar, Gerhard H. Schiroky, Kevin P. Pochopien, Vilupanur A. Ravi, James C. Wang, Ratnesh K. Dwivedi
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Patent number: 5301738Abstract: The present invention relates to modifying the properties of a metal matrix composite body by a post formation process modification treatment. The post formation process treatment may be applicable to a variety of metal matrix composite bodies produced by various techniques, and is particularly applicable to modifying the properties of a metal matrix composite body produced by a spontaneous infiltration technique. Particularly, at least a portion of the matrix metal of the metal matrix composite body and/or the filler material of the metal matrix composite body is modified or altered after the formation process. Preferably, the preform contains a second non-metal material, an infiltration enhancer of infiltration enhancer precursor, and an infiltration atmosphere.Type: GrantFiled: February 24, 1992Date of Patent: April 12, 1994Assignee: Lanxide Technology Company, LPInventors: Marc S. Newkirk, Andrew W. Urquhart, Michael K. Aghajanian, Mark G. Mortenson, Vilupanur A. Ravi, Alan S. Nagelberg