Patents by Inventor A. Prasad

A. Prasad 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: 6025514
    Abstract: Disclosed herein is a process for preparing high yields of methyl dithiocarbazinate by reacting carbon disulfide, hydrazine and a base in an aqueous medium, in an effective ratio to form a dithiocarbazinate salt followed by methylating the dithiocarbazinate salt with methyl bromide.
    Type: Grant
    Filed: September 21, 1998
    Date of Patent: February 15, 2000
    Assignee: Bayer Corporation
    Inventors: Dennis E. Jackman, David T. Erdman, Peter E. Newallis, Daniel M. Wasleski, Vijay C. Desai, Jeffrey D. Macke, Vidyanatha A. Prasad
  • Patent number: 6022908
    Abstract: A set of printing liquids is disclosed comprising a first anionic printing liquid comprising an aqueous vehicle, at least one first colorant, and at least one first anionic polymer; a second anionic printing liquid comprising an aqueous vehicle at least one second colorant, at least one second anionic polymer, and an acid additive having a pKa up to the pKa of the at least first polymer of the first liquid; a third cationic printing liquid comprising an aqueous vehicle, at least one third colorant, at least one third cationic polymer, and a pH in the range from about 2 to about 5; and a fourth anionic printing liquid comprising an aqueous vehicle, at least one fourth anionic dye, and a precipitating agent. More specifically, the present set of printing liquids may find application in ink-jet printing.
    Type: Grant
    Filed: April 22, 1998
    Date of Patent: February 8, 2000
    Assignee: Hewlett-Packard Company
    Inventors: Zeying Ma, Keshava A. Prasad
  • Patent number: 6012118
    Abstract: A split transaction bus in a computer system that permits out-of-order replies in a pipelined manner using an additional bus for use in the response phase.
    Type: Grant
    Filed: October 20, 1997
    Date of Patent: January 4, 2000
    Assignee: Intel Corporation
    Inventors: Muthurajan Jayakumar, Sunny C. Huang, Peter D. MacWilliams, William S. Wu, Stephen Pawlowski, Bindi A. Prasad
  • Patent number: 6005114
    Abstract: The present invention provides a process for making 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole. The process includes the steps of reacting methyldithiocarbazinate with trifluoroacetic acid to form a mixture of 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole and 2,5-bis-(methylthio)-1,3,4-thiadiazole and selectively removing the 2,5-bis-(methylthio)-1,3,4-thiadiazole by acidifying the mixture.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: December 21, 1999
    Assignees: Bayer Corporation, Bayer Aktiengesellschaft
    Inventors: Vidyanatha A. Prasad, Thomas Schmidt, Peter E. Newallis
  • Patent number: 5964856
    Abstract: In a microprocessor system having a bus clock running at a bus clock rate, a method for reducing an idle interval between a first data transfer and a second data transfer, the method comprising the steps of:providing a first strobe signal and a second strobe signal for synchronizing said first and second data transfers with the bus clock;a pre-driving the first strobe signal before the first data transfer, the first strobe signal running at the bus clock rate during the first data transfer; andpre-driving one of the first and second strobe signals before the second data transfer, said one of the first and second strobe signals running at the bus clock rate during the second data transfer.
    Type: Grant
    Filed: September 30, 1997
    Date of Patent: October 12, 1999
    Assignee: Intel Corporation
    Inventors: William S. Wu, Leonard Schultz, Dilip K. Sampath, Muthurajan Jayakumar, Bindi A. Prasad
  • Patent number: 5965737
    Abstract: The present invention provides a process for making thiadiazole sulfones. In particular, the present process is used to make 2-(methyl-sulfonyl)-5-(trifluoromethyl)-1,3,4-thiadiazole using catalytic oxidation in the presence of a suitable oxidizing agent. A preferred oxidizing agent is hydrogen peroxide. The catalyst system used for the oxidation reaction is a mixture of boric acid and glacial acetic acid. The molar ratio of glacial acetic acid to 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole is from about 0.1:1 to about 0.5:1.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: October 12, 1999
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Joe J. Hanson, Klaus Jelich
  • Patent number: 5946012
    Abstract: An inkjet drop ejection system comprises a combination of printhead components and ink, mutually tuned to maximize operating characteristics of the printhead and print quality and dry time of the ink. Use of a short shelf (distance from ink source to ink firing element), on the order of 55 microns, provides a very high speed refill. However, it is a characteristic of high speed refill that it has a tendency for being over-damped. To provide the requisite damping, the ink should have a viscosity greater than about 2 cp. In this way, the ink and architecture work together to provide a tuned system that enables stable operation at high frequencies. One advantage of the combination of a pigment and a dispersant in the ink is the resultant higher viscosity provided. The high speed would be of little value if the ink did not have a fast enough rate of drying. This is accomplished by the addition of alcohols or alcohol(s) and surfactant(s) to the ink.
    Type: Grant
    Filed: June 4, 1998
    Date of Patent: August 31, 1999
    Assignee: Hewlett-Packard Co.
    Inventors: Kenneth J. Courian, John L. Stoffel, Richard A. Sader, Keshava A. Prasad, Steven L. Webb, David H. Donovan, Jules G. Moritz, III, Brian J. Keefe, Steven W. Steinfield, Winthrop D. Childers
  • Patent number: 5936113
    Abstract: The present invention provides a method for making O,S-dimethyl phosphoramidothioate. In accordance with that process, a mixture containing O,S-dimethyl phosphoramidothioate is lagered at a temperature of from 35.degree. C. to about 45.degree. C. for from about 3 to about 6 hours.
    Type: Grant
    Filed: December 10, 1997
    Date of Patent: August 10, 1999
    Assignee: Bayer Corporation
    Inventors: Vidyantha A. Prasad, Klaus Jelich, Donald K. Smith
  • Patent number: 5922404
    Abstract: The present invention relates to an integrated process for synthesizing dimethyl (2,2,2-trichloro-1-hydroxyethyl)-phosphonate and a process for impregnating the dimethyl (2,2,2-trichloro-1-hydroxyethyl)-phosphonate on to inert carrier granules. The process involves adding dimethyl phosphite to a reaction mixture containing chloral under anhydrous, inert conditions. The molar ratio of chloral to dimethyl phosphite used in the reaction mixture is from about 1.0:1.0 to about 1.1:1.0. The impregnation process involves transferring molten dimethyl (2,2,2-trichloro-1-hydroxyethyl)-phosphonate into a process vessel and discharging weighed aliquots into a formulation vessel to form a granular product containing dimethyl (2,2,2-trichloro-1-hydroxyethyl)-phosphonate.
    Type: Grant
    Filed: September 29, 1997
    Date of Patent: July 13, 1999
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Klaus Jelich, Christopher M. Tusa, Daniel E. Terry, Stephen C. Slahck, Scott P. Hensley
  • Patent number: 5922896
    Abstract: The present invention provides a method for making O,S-dimethyl phosphoramidothioate. In accordance with the present process, O,O-dimethyl phosphoramidothioate is isomerized in the presence of a catalyst at a temperature of from about 35.degree. C. to about 45.degree. C. to form a mixture containing O,S-dimethyl phosphoramidothioate and the resultant mixture is lagered at a temperature of from about 35.degree. C. to about 45.degree. C. for about 3 to 6 hours. The total time for both steps is at least about 4 hours.
    Type: Grant
    Filed: December 10, 1997
    Date of Patent: July 13, 1999
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Klaus Jelich, Donald K. Smith
  • Patent number: 5905157
    Abstract: The present invention provides a process of making 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole. The process includes the steps of (a) reacting methyldithiocarbazinate with a molar excess of trifluoroacetic acid; and (b) removing the water and excess trifluoroacetic acid. Water and excess trifluoroacetic acid are preferably removed via distillation.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: May 18, 1999
    Assignees: Bayer Corporation, Bayer Aktiengesellschaft
    Inventors: Vijay C. Desai, Peter E. Newallis, Vidyanatha A. Prasad, Herman Seifert
  • Patent number: 5898074
    Abstract: The present invention provides a process for preparing 2-(methylthio)-5-(trifluoromethyl)-1,3,4-thiadiazole. The process includes the steps of reacting methyldithiocarbazinate with a molar excess of trifluoroacetic acid and recovering the excess trifluoroacetic acid.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: April 27, 1999
    Assignees: Bayer Corporation, Bayer Aktiengesellschaft
    Inventors: Vidyanatha A. Prasad, Achim Noack
  • Patent number: 5895818
    Abstract: The present invention relates to a process for making N-(4-fluorophenyl)-N-(1-methylethyl)-2-?(5-trifluoromethyl)-1,3,4-thiadiaz ol-2-yl)oxy!acetamide in an aprotic, aromatic solvent. The process includes the steps of: (a) reacting 2-(methylsulfonyl)-5-(trifluoromethyl)-1,3,4-thiadiazole with N-(4-fluorophenyl)-2-hydroxy-N-(1-methylethyl)acetamide in the presence of an aprotic, aromatic solvent to form an aqueous phase and an organic phase; (b) acidifying the phases, (c) separating the phases; and (d) recovering the N-(4-fluorophenyl)-N-(1-methylethyl)-2-?(5-trifluoromethyl)-1,3,4-thiadiaz ol-2-yl)oxy!acetamide from the organic phase.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: April 20, 1999
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Peter E. Newallis, Daniel M. Wasleski, Jacqueline M. Applegate, Klaus Jelich
  • Patent number: 5880758
    Abstract: A color ink-jet printer is provided, with one pen for dispensing black ink onto a print medium and at least one pen for dispensing color ink onto a print medium. The pen for dispensing black ink is adapted to jet droplets of black ink of a first volume and the pen(s) for dispensing color ink are adapted to jet droplets of color ink of a second volume, with the first volume being larger than the second volume. Such a color ink-jet printer provides both superior text quality of the black ink and does not require as much ink volume of the color ink(s) as previous ink-jet printers.
    Type: Grant
    Filed: March 27, 1997
    Date of Patent: March 9, 1999
    Assignee: Hewlett-Packard Company
    Inventors: John L. Stoffel, Keshava A. Prasad, Ronald A. Askeland, Michele E. Shepard, Frank Drogo, Leonard Slevin, Mark S. Hickman, Clayton L. Holstun
  • Patent number: 5877339
    Abstract: Disclosed herein is an aqueous process for preparing high yields of methyl dithiocarbazinate by reacting carbon disulfide and hydrazine in an effective ratio, in an aqueous medium to form hydrazinium dithiocarbazinate salt followed by methylating the hydrazinium dithiocarbazinate with methyl bromide.
    Type: Grant
    Filed: November 7, 1996
    Date of Patent: March 2, 1999
    Assignee: Bayer Corporation
    Inventors: Daniel M. Wasleski, Peter E. Newallis, Dennis E. Jackman, David T. Erdman, Jeffrey D. Macke, Vidyanatha A. Prasad, Vijay C. Desai
  • Patent number: 5874974
    Abstract: An inkjet drop ejection system comprises a combination of printhead components and ink, mutually tuned to maximize operating characteristics of the printhead and print quality and dry time of the ink. Use of a short shelf (distance from ink source to ink firing element), on the order of 55 microns, provides a very high speed refill. However, it is a characteristic of high speed refill that it has a tendency for being overdamped. To provide the requisite damping, the ink should have a viscosity greater than about 2 cp. In this way, the ink and architecture work together to provide a tuned system that enables stable operation at high frequencies. One advantage of the combination of a pigment and a dispersant in the ink is the resultant higher viscosity provided. The high speed would be of little value if the ink did not have a fast enough rate of drying. This is accomplished by the addition of alcohols or alcohol(s) and surfactant(s) to the ink.
    Type: Grant
    Filed: February 28, 1996
    Date of Patent: February 23, 1999
    Assignee: Hewlett-Packard Company
    Inventors: Kenneth J. Courian, John L. Stoffel, Richard A. Sader, Keshava A. Prasad, Steven L. Webb, David H. Donovan, Jules G. Moritz, III, Brian J. Keefe, Steven W. Steinfield, Winthrop D. Childers
  • Patent number: 5856499
    Abstract: The present invention provides a process for making thiadiazole sulfones. The present process is used to make 2-(methylsulfonyl)-5-(trifluoromethyl)-1,3,4-thiadiazole. 2-(Methylsulfonyl)-5-(trifluoromethyl)-1,3,4-thiadiazole is made using catalytic oxidation in the presence of a suitable oxidizing agent. The catalyst used for the oxidation reaction is glacial acetic acid.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: January 5, 1999
    Assignees: Bayer Corporation, Bayer Aktiengesellschaft
    Inventors: Vidyanatha A. Prasad, Jacqueline M. Applegate, Klaus Jelich, Achim Noack
  • Patent number: 5852202
    Abstract: The present invention relates to a process for isolating N-(4-fluorophenyl)-N-(1-methylethyl)-2-?(5-trifluoromethyl)-1,3,4-thiadiaz ol-2-yl)oxy!acetamide from a solution of N-(4-fluorophenyl)-N-(1-methylethyl)-2-?(5-trifluoromethyl)-1,3,4-thiadiaz ol-2-yl)oxy!acetamide in an aprotic, aromatic solvent. The process includes the steps of: (a) removing the solvent from the solution to form a substantially solvent-free material; (b) melting the material from step (a) to form a molten material; and (c) isolating N-(4-fluorophenyl)-N-(1-methylethyl)-2-?(5-trifluoromethyl)-1,3,4-thiadiaz ol-2-yl)oxy!acetamide from the molten material by flaking.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: December 22, 1998
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Jonathan D. Spicher, Warren A. Fischer
  • Patent number: 5831112
    Abstract: The invention is directed to a process for producing a stable, low odor S,S,S-tributylphosphorotrithioate having a level of dibutyl disulfide of 0.3% by weight or less. The process broadly includes the steps ofa) reacting S,S,S-tributylphosphorotrithioite with an oxidizing agent to produce a crude S,S,S-tributylphosphorotrithioate,b) treating the crude product with sodium bisulfite to decompose any excess oxidizing agent,c) adding a caustic solution having a caustic concentration of from 25 to 50% by weight directly to the reaction mixture of step b), the addition of said caustic solution being stopped once the total caustic concentration is less than 10% by weight and once the pH is constant, andd) phase separating S,S,S-tributylphosphorotrithioate from the mixture of step c).
    Type: Grant
    Filed: June 20, 1997
    Date of Patent: November 3, 1998
    Assignee: Bayer Corporation
    Inventors: Vidyanatha A. Prasad, Peter E. Newallis
  • Patent number: 5808153
    Abstract: The present invention provides a process for converting N-(4-fluorophenyl)-2-hydroxy-N-(1-methylethyl)acetamide acetate to N-(4-fluorophenyl)-2-hydroxy-N-(1-methylethyl)acetamide. The process includes the step of hydrolyzing N-(4-fluorophenyl)-2-hydroxy-N-(1-methylethyl)acetamide acetate with water or an aqueous alkali in the presence of an aprotic, aromatic solvent.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: September 15, 1998
    Inventor: Vidyanatha A. Prasad