Patents by Inventor Pradeep K. Rohatgi
Pradeep K. Rohatgi 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: 11408056Abstract: The present invention provides an aluminum hybrid metal matrix composite including cerium and graphite. The aluminum-cerium intermetallic is stable at temperatures up to a melting point of aluminum and graphite provides in situ lubrication. This stability is advantageous in applications such as cylinder liners and other applications where strength and stiffness at elevated temperatures are required.Type: GrantFiled: August 7, 2018Date of Patent: August 9, 2022Assignee: Intelligent Composites, LLCInventors: David J. Weiss, Pradeep K. Rohatgi, Christopher T. Jordan, Simon S. Beno, James H. Hunter, III, Benjamin F. Schultz
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Publication number: 20190040496Abstract: The present invention provides an aluminum hybrid metal matrix composite including cerium and graphite. The aluminum-cerium intermetallic is stable at temperatures up to a melting point of aluminum and graphite provides in situ lubrication. This stability is advantageous in applications such as cylinder liners and other applications where strength and stiffness at elevated temperatures are required.Type: ApplicationFiled: August 7, 2018Publication date: February 7, 2019Inventors: David J. Weiss, Pradeep K. Rohatgi, Christopher T. Jordan, Simon S. Beno, James. H. Hunter, III, Benjamin F. Schultz
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Patent number: 8518531Abstract: The invention discloses the internal structures and processes to synthesize the structure of self-healing materials, specially metallic materials, metal matrix micro and nanocomposites. Self healing is imparted by incorporation of macro, micro or nanosize hollow reinforcements including nanotubes, filled with low melting healing material or incorporation of healing material in pockets within the metallic matrix; the healing material melts and fills the crack. In another concept, macro, micro and nanosize solid reinforcements including ceramic and metallic particles, and shape memory alloys are incorporated into alloy matrices, specially nanostructured alloy matrices, to impart self healing by applying compressive stresses on the crack or diffusing material into voids to fill them.Type: GrantFiled: August 7, 2009Date of Patent: August 27, 2013Inventor: Pradeep K. Rohatgi
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Patent number: 8520210Abstract: Methods for increasing the amount of cenospheres in a fly ash sample are disclosed. The cenospheres are obtained in a dry state by using air as the “fluid” media for separation. In one version, the invention is a two step process, that is, screen by size followed by density separation such as in a fluidizing vertical column by density. In another version of the invention, the separation by density is followed by screening by size. Additional cycles can improve purity as defined by concentration of cenospheres.Type: GrantFiled: November 7, 2011Date of Patent: August 27, 2013Assignee: Wisconsin Electric Power CompanyInventors: Bruce W. Ramme, John J. Noegel, Pradeep K. Rohatgi
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Publication number: 20120050519Abstract: Methods for increasing the amount of cenospheres in a fly ash sample are disclosed. The cenospheres are obtained in a dry state by using air as the “fluid” media for separation. In one version, the invention is a two step process, that is, screen by size followed by density separation such as in a fluidizing vertical column by density. In another version of the invention, the separation by density is followed by screening by size. Additional cycles can improve purity as defined by concentration of cenospheres.Type: ApplicationFiled: November 7, 2011Publication date: March 1, 2012Inventors: Bruce W. Ramme, John J. Noegel, Pradeep K. Rohatgi
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Patent number: 8074804Abstract: Methods for increasing the amount of cenospheres in a fly ash sample are disclosed. The cenospheres are obtained in a dry state by using air as the “fluid” media for separation. In one version, the invention is a two step process, that is, screen by size followed by density separation such as in a fluidizing vertical column by density. In another version of the invention, the separation by density is followed by screening by size. Additional cycles can improve purity as defined by concentration of cenospheres.Type: GrantFiled: February 11, 2008Date of Patent: December 13, 2011Assignee: Wisconsin Electric Power CompanyInventors: Bruce W. Ramme, John J. Noegel, Pradeep K. Rohatgi
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Publication number: 20110033721Abstract: The invention discloses the internal structures and processes to synthesize the structure of self-healing materials, specially metallic materials, metal matrix micro and nanocomposites. Self healing is imparted by incorporation of macro, micro or nanosize hollow reinforcements including nanotubes, filled with low melting healing material or incorporation of healing material in pockets within the metallic matrix; the healing material melts and fills the crack. In another concept, macro, micro and nanosize solid reinforcements including ceramic and metallic particles, and shape memory alloys are incorporated into alloy matrices, specially nanostructured alloy matrices, to impart self healing by applying compressive stresses on the crack or diffusing material into voids to fill them.Type: ApplicationFiled: August 7, 2009Publication date: February 10, 2011Inventor: Pradeep K. Rohatgi
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Publication number: 20080190327Abstract: Methods for increasing the amount of cenospheres in a fly ash sample are disclosed. The cenospheres are obtained in a dry state by using air as the “fluid” media for separation. In one version, the invention is a two step process, that is, screen by size followed by density separation such as in a fluidizing vertical column by density. In another version of the invention, the separation by density is followed by screening by size. Additional cycles can improve purity as defined by concentration of cenospheres.Type: ApplicationFiled: February 11, 2008Publication date: August 14, 2008Inventors: Bruce W. Ramme, John J. Noegel, Pradeep K. Rohatgi
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Patent number: 5899256Abstract: Metal matrix composites are made by infiltrating packed loose fly ash with molten metal or metal alloy under low pressure. In some embodiments the infiltration is driven by pressurized gas. Coating the fly ash prior to infiltration can lower the threshold of pressure required for satisfactory infiltration by the molten metal. In some embodiments nickel coated cenosphere fly ash is employed. Resulting metal-fly ash composites have high volume fractions of fly ash, and the fly ash is uniformely distributed in the metal matrix. The densities of the composites are relatively low, particularly in composites made using cenosphere fly ash.Type: GrantFiled: October 3, 1997Date of Patent: May 4, 1999Assignee: Electric Power Research Institute, Inc.Inventor: Pradeep K. Rohatgi
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Patent number: 5897943Abstract: Metal matrix composites comprising of a solid preform comprising of a filler phase containing fly ash and a binding material having a binder to water ratio of 1:1 to 1:9, wherein the preform contains a metal homogeneously distributed within the preform.Type: GrantFiled: January 23, 1997Date of Patent: April 27, 1999Assignee: Electric Power Research Institute, Inc.Inventor: Pradeep K. Rohatgi
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Patent number: 5803153Abstract: Inserts of powder compacts or metal matrix composite inserts in the form of rods, bars, plates, wires, wire mesh, ribbons, chaplets, mold coatings or machining chips are placed in the sprue, sprue basin, runner, or a mold in gate of a static sand mold. The molten metal stream partly or completely melts the inserts releasing the reinforcements which get mixed with the molten alloy streams to form the shaped casting of the composite.Type: GrantFiled: August 26, 1996Date of Patent: September 8, 1998Inventor: Pradeep K. Rohatgi
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Patent number: 5765624Abstract: A iron-based material such as cast iron is made by a process wherein filler particles are added to an iron base metal, as the base metal is poured into the mold. Pieces containing ceramic filler particles held together by a binder can be disposed in the mold prior to pouring molten iron base metal therein. Molten iron base metal is then poured into the mold so that the molten base metal contacts the pieces, gradually dissolving the filler. The filler becomes distributed throughout the molten base metal within the mold. Upon cooling, the base metal has the filler distributed therein, resulting in a iron-based material. The resulting material is particularly useful for making vehicle parts normally made of cast iron or steel.Type: GrantFiled: October 23, 1995Date of Patent: June 16, 1998Assignee: Oshkosh Truck CorporationInventors: Robert M. Hathaway, Pradeep K. Rohatgi
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Patent number: 5711362Abstract: A reinforcing phase comprising fly ash is combined with an aqueous medium comprising a binder to produce a slurry. The slurry is then dried to produce a preform of the reinforcing phase. Molten metal is then introduced into the preform, resulting in a metal matrix composites. The reinforcing phase of the subject composites may be present in excess of 50%.Type: GrantFiled: November 29, 1995Date of Patent: January 27, 1998Assignee: Electric Power Research InstituteInventor: Pradeep K. Rohatgi
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Patent number: 5626692Abstract: The invention provides an aluminum-base composite material. The aluminum-base material contains a uniform distribution of carbide particles and lubricating phase particles such as carbon or graphite. The carbide particles increase hardness for improved wear resistance. The lubricating phase particles provide improved wear resistance and especially improve unlubricated wear resistance under increased loads. Finally, a dispersoid of nickel aluminide intermetallic phase may also be used to provide additional hardness and wear resistance. The composite is formed by introducing carbide particles and lubricating phase such as graphite into a molten aluminum alloy to neutraliize buoyancy and to form an aluminum-base mixture. Mixing the aluminum-base mixture to uniformly distribute carbide and carbon particles throughout the molten aluminum. Carbide and carbon particles counteract each other to remain uniformly distributed throughout the aluminum-base alloy despite prolonged holding or cooling times.Type: GrantFiled: March 1, 1994Date of Patent: May 6, 1997Assignee: INCO LimitedInventors: Pradeep K. Rohatgi, James A. E. Bell, Thomas F. Stephenson
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Patent number: 5407495Abstract: A metal matrix composite consisting of aluminum silicon alloy reinforced with graphite fibers exhibits improved mechanical and physical properties when the graphite fibers are subjected to external cooling.Type: GrantFiled: September 22, 1993Date of Patent: April 18, 1995Assignee: Board of Regents of the University of Wisconsin System on behalf of the University of Wisconsin-MilwaukeeInventor: Pradeep K. Rohatgi
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Patent number: 5228494Abstract: A method of casting metal matrix composites wherein there is a wide disparity in the respective densities of the metal matrix and the reinforcing particles. The particles are added to a melt of molten metal and the mixture is stirred using an impeller rotating at a high speed so as to ensure an even distribution of the less dense reinforcing particles throughout the denser metal matrix.Type: GrantFiled: May 1, 1992Date of Patent: July 20, 1993Inventor: Pradeep K. Rohatgi
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Patent number: 5200003Abstract: A process for producing a copper alloy composite containing dispersed graphite. The process comprises locating compacted uncoated graphite in a preheated die, pouring molten copper alloy over the compacted graphite and infiltrating the compacted graphite with the molten copper alloy.Type: GrantFiled: December 28, 1990Date of Patent: April 6, 1993Assignee: Board of Regents of the University of Wisconsin System on behalf of the University of Wisconsin-MilwaukeeInventor: Pradeep K. Rohatgi
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Patent number: 4946647Abstract: A process is disclosed for the manufacture of aluminium-graphite particulate composite using uncoated graphite particles for automobile and engineering applications. In the process the aluminium-alloy melt is treated with a reactive metal to increase the wettability of the alloy and the graphite particles. Further treatment of the melt and gradual addition of activated graphite powder and stirring at about 500 to about 600 r.p.m. at a temperature of about 700.degree. to about 720.degree. C. result in the composite.Type: GrantFiled: May 4, 1988Date of Patent: August 7, 1990Inventors: Pradeep K. Rohatgi, Tapan K. Dan, Arya, S. C., S. V. Prasad, Das, S., A. K. Gupta, B. K. Prasad, Amol K. Jha