Patents by Inventor David K. Hoffman

David K. Hoffman 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: 11827954
    Abstract: Disclosed herein are methods for preparing a hydraulic pre-concentrate enriched in rare earth elements and critical minerals, the method comprising: (a) contacting a raw material with a first base in an amount sufficient to adjust the pH to a value from about 4.0 to about 6.0, thereby forming a mixture comprising a first aqueous phase and a first solid concentrate; (b) separating the first aqueous phase from the first solid concentrate; (c) contacting the first aqueous phase with a second base in an amount sufficient to adjust the pH to a value from about 7.0 to about 9.0, thereby forming a mixture comprising a second aqueous phase and the hydraulic pre-concentrate; (d) removing the second aqueous phase and collecting the hydraulic pre-concentrate; wherein the raw material comprises rare earth elements; and wherein the hydraulic pre-concentrate is enriched in rare earth elements.
    Type: Grant
    Filed: July 28, 2022
    Date of Patent: November 28, 2023
    Assignee: West Virginia University
    Inventors: Paul F. Ziemkiewicz, James Constant, David K. Hoffman, John D. Quaranta
  • Publication number: 20230039988
    Abstract: The present disclosure relates to processes for treating a coal associated material, e.g., acid mine drainage, while simultaneously recovering a high-grade rare earth preconcentrate suitable for extraction of commercially valuable rare earth oxides. Disclosed herein are methods for preparing a hydraulic pre-concentrate enriched in rare earth elements and critical minerals. Also disclosed herein are methods for preparing a pregnant leach solution from the disclosed hydraulic pre-concentrates. The present disclosure also relates to systems and plants for carrying out the disclosed processes. Also disclosed are compositions produced by the process disclosed herein in which the compositions comprise rare earth elements. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
    Type: Application
    Filed: July 28, 2022
    Publication date: February 9, 2023
    Inventors: Paul F. Ziemkiewicz, James Constant, David K. Hoffman, John D. Quaranta
  • Publication number: 20220340997
    Abstract: The present disclosure relates to processes for treating a coal associated material, e.g., acid mine drainage, while simultaneously recovering a high-grade rare earth preconcentrate suitable for extraction of commercially valuable rare earth oxides. Disclosed herein are methods for preparing a hydraulic pre-concentrate enriched in rare earth elements and critical minerals. Also disclosed herein are methods for preparing a pregnant leach solution from the disclosed hydraulic pre-concentrates. The present disclosure also relates to systems and plants for carrying out the disclosed processes. Also disclosed are compositions produced by the process disclosed herein in which the compositions comprise rare earth elements. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.
    Type: Application
    Filed: March 28, 2022
    Publication date: October 27, 2022
    Inventors: Paul F. ZIEMKIEWICZ, James CONSTANT, David K. HOFFMAN, JR., John D. QUARANTA
  • Patent number: 7689056
    Abstract: A non-separable multiresolution structure based on frames by radial scaling functions is disclosed, which are minimally supported in the frequency. Resulting frame multiwavelets are also disclosed which can be isotropic. The construction can be carried out in any number of dimensions and for a variety of dilation matrices.
    Type: Grant
    Filed: March 12, 2004
    Date of Patent: March 30, 2010
    Assignee: The University of Houston System
    Inventors: Emmanouil I. Papadakis, Donald J. Kouri, David K. Hoffman, Ioannis A Kakadiaris, Grigoriy Gogoshin
  • Patent number: 7272265
    Abstract: A method for padding, filtering, denoising, image enhancing and increased time-frequency acquisition is described for digitized data of a data set is described where unknown data is estimated using real data by adding unknown data points in a manner that the padding routine can estimate the interior data set including known and unknown data to a given accuracy on the known data points. The method also provides filtering using non-interpolating, well-tempered distributed approximating functional (NIDAF)-low-band-pass filters. The method also provides for symmetric and/or anti-symmetric extension of the data set so that the data set may be better refined and can be filtered by Fourier and other type of low frequency or harmonic filters.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: September 18, 2007
    Assignee: The University of Houston System
    Inventors: Donald K. Kouri, David K. Hoffman, Mark Arnold, Ioannis A. Kakadiaris, Zhuoer Shi, DeSheng Zhang, Gemunu H. Gunaratne, Haixiang Wang, Guowei W. Wei, Zheng Bao Xi'an
  • Patent number: 7212933
    Abstract: A method and system for solving the inverse acoustic scattering problem using an iterative approach with consideration of half-off-shell transition matrix elements (near-field) information, where the Volterra inverse series correctly predicts the first two moments of the interaction, while the Fredholm inverse series is correct only for the first moment and that the Volterra approach provides a method for exactly obtaining interactions which can be written as a sum of delta functions.
    Type: Grant
    Filed: March 22, 2004
    Date of Patent: May 1, 2007
    Assignee: The University of Houston System
    Inventors: Donald J. Kouri, Amrendra Vijay, Haiyan Zhang, Jingfeng Zhang, David K. Hoffman
  • Patent number: 6847737
    Abstract: A method for padding, filtering, denoising, image enhancing and increased time-frequency acquisition is described for digitized data of a data set where unknown data is estimated using real data by adding unknown data points in a manner that the padding routine can estimate the interior data set including known and unknown data to a given accuracy on the known data points. The method also provides filtering using non-interpolating, well-tempered distributed approximating functional (NIDAF)-low-band-pass filters. The method also provides for symmetric and/or anti-symmetric extension of the data set so that the data set may be better refined and can be filtered by Fourier and other type of low frequency or harmonic filters.
    Type: Grant
    Filed: March 12, 1999
    Date of Patent: January 25, 2005
    Assignees: University of Houston System, Iowa State University Research Foundation, Inc.
    Inventors: Donald J. Kouri, David K. Hoffman, Ioannis Kakadiaris, Zhuoer Shi, DeSheng Zhang, Gemunu H. Gunaratne, Haixiang Wang, G. W. Wei, Zheng Bao
  • Publication number: 20040071363
    Abstract: A method for padding, filtering, denoising, image enhancing and increased time-frequency acquisition is described for digitized data of a data set is described where unknown data is estimated using real data by adding unknown data points in a manner that the padding routine can estimate the interior data set including known and unknown data to a given accuracy on the known data points. The method also provides filtering using non-interpolating, well-tempered distributed approximating functional (NIDAF)-low-band-pass filters. The method also provides for symmetric and/or anti-symmetric extension of the data set so that the data set may be better refined and can be filtered by Fourier and other type of low frequency or harmonic filters.
    Type: Application
    Filed: June 4, 2003
    Publication date: April 15, 2004
    Inventors: Donald J. Kouri, David K. Hoffman, Ioannis A. Kakadiaris, Zhuoer Shi, DeSheng Zhang, Gemunu H. Gunaratne, Mark Arnold, Haixiang Wang, Guowei W. Wei, Zheng Bao
  • Patent number: 5472577
    Abstract: A pump for exerting a pumping force on a fluid in an attached conduit, the pump being actuated by a voltage from a power supply, the pump comprising a liquid metal pool, a containment vessel for confining the pool, an inner tubular member in hydraulic contact with the attached conduit and with an open end disposed in the pool to divide a free upper surface of the pool into an actuation surface and a working surface, an electrolyte in contact with the actuation surface, an electrode in contact with the electrolyte, and an electrode in contact with the pool, such that application of a voltage to the electrodes causes a surface tension change in the actuation surface and a resulting height change in the working surface, whereby a pumping action is transferred to the fluid in the attached conduit.
    Type: Grant
    Filed: June 30, 1994
    Date of Patent: December 5, 1995
    Assignee: Iowa State University Research Foundation
    Inventors: Marc D. Porter, David K. Hoffman, Chuan-Jian Zhong