About

David Cox is a Professor Emeritus in the Department of Chemical Engineering at Virginia Tech. He holds a Ph.D. from the University of Florida earned in 1984, an M.S. from the same university obtained in 1980, and a B.S. from the University of Tennessee completed in 1979. His research interests include structure-property relationships in surface chemistry and catalysis by compound materials, ultrahigh vacuum surface science studies of oxides, carbides, and phosphides, as well as density functional investigations of bulk minerals, compound surfaces, adsorption, surface reactions, and electronic properties of defects. His work focuses on understanding the fundamental aspects of surface chemistry and catalysis, contributing to the advancement of chemical engineering knowledge in these areas.

Research topics

• Chemistry
• Physical chemistry
• Nanotechnology
• Inorganic chemistry
• Materials science
• Chemical engineering
• Computational chemistry
• Immunology
• Organic chemistry
• Crystallography
• Medicine
• Biology
• Internal medicine

Selected publications

• Combined novel homozygous variants in both SGPL1 and STAT1 presenting with severe combined immune deficiency: case report and literature review

  Frontiers in Immunology · 2023 · 6 citations

  • Medicine
  • Immunology
  • Internal medicine

  Background: loss of function (LOF) variants lead to STAT1 deficiency with a severe phenotype of immunodeficiency with increased frequency of infections and poor outcome if untreated. Case presentation: variants in a newborn of Gambian ethnicity with clinical features of SPLIS and severe combined immunodeficiency. The patient presented early in life with nephrotic syndrome, severe respiratory infection requiring ventilation, ichthyosis, and hearing loss, with T-cell lymphopenia. The combination of these two conditions led to severe combined immunodeficiency with inability to clear respiratory tract infections of viral, fungal, and bacterial nature, as well as severe nephrotic syndrome. The child sadly died at 6 weeks of age despite targeted treatments. Conclusion: variant can be offered curative treatment with HSCT.

  PublisherOA PDFDOI

• Carbon Deposition on AGR Fuel Pins

  2022-01-05

  book-chapter

  HREM studies of carbon removed from the surface of an AGR fuel-pin show the presence of at least three forms of carbon. These can be described broadly as: lamellar, microcrystalline and filamentous. The degree of ordering and stacking of the sheets of hexagonally packed carbon atoms observed is unlikely to arise solely from pyrolidc deposition and some catalytic intervention is envisaged. Protection from carbon deposition can be obtained by creating Cr-rich surfaces. Initial experiments demonstrating the nucleation and growth of Cr oxides from grain boundaries are presented.

  PublisherDOI

• Hydrocarbon, Oxidation, Dehydrogenation and Coupling Over Model Metal Oxide Surfaces

  2022-11-01

  reportOpen access1st authorCorresponding

  Final report for a 24.5 year single investigator project aimed at understanding structure/function relationships in adsorption and reaction on metal oxide surfaces for understanding heterogeneous catalysis. An experimental surface science approach was taken using single crystal surfaces as model catalysts and supplemented by density functional theory (DFT) calculations. Materials studied experimentally and computationally include the base metal oxide SnO2 and transition metal oxides α-Cr2O3, α-Fe2O3 and MnO.

  PublisherOA PDFDOI

• Asynchronous Logic Design with Flip-Flop Constraints

  Digital Commons - USU (Utah State University) · 2021-10-08

  articleOpen access1st authorCorresponding

  Some techniques are presented to permit the implementation of asynchronous sequential circuits using standard flip-flops. An algorithm is presented for the RS flip-flop, and it is shown that any flow table may be realized using the algorithm (the flow table is assumed to be realizable using standard logic gates). The approach is shown to be directly applicable to synchronous circuits, and transition flip-flops (JK, D, and T) are analyzed using the ideas developed. Constraints are derived for the flow tables to meet to be realizable using transition flip-flops in asynchronous situations, and upper and lower bounds on the number of transition flip-flops required to implement a given flow table are stated.

  PublisherOA PDFDOI

• Synthesis of a planar, multicomponent catalytic surface of Na2CO3/MnO

  Surface Science · 2021 · 7 citations

  Senior authorCorresponding
  • Chemistry
  • Inorganic chemistry
  • Chemical engineering
  PublisherOA PDFDOI

• CO adsorption on MnO(100): Experimental benchmarks compared to DFT

  Surface Science · 2021 · 16 citations

  Senior authorCorresponding
  • Materials science
  • Chemistry
  • Physical chemistry
  PublisherOA PDFDOI

• The incompressibility of atoms at high pressures

  American Mineralogist · 2020-06-22 · 3 citations

  article

  Abstract The structures of the silica polymorphs α-quartz and stishovite have been geometry optimized at highly simulated isotropic pressure within the framework of Density Functional Theory. The atoms of the high-pressure polymorph stishovite are virtually incompressible with the bonded radii for Si and O atoms decreasing by only 0.04 and 0.08 Å, respectively, at 100 GPa. In compensating for the increase in the effective interatomic potential associated with the compression of the Si-O bonded interactions, the electron density at the bond critical point between the bonded pair increases from 0.69 to 0.89 e/Å 3. The bonded radii of the Si and O atoms for α-quartz decrease by 0.006 and 0.008 Å, respectively, between 1 bar and 26.4 GPa. The impact of simulated, isotropic pressure on the bonded radii of the atoms for three perovskites YAlO3, LaAlO3, and CaSnO3 was also examined at high pressure. For the YAlO3 perovskite, the bonded radii for Y and Al decrease by 0.06 and 0.05 Å, respectively, at 80 GPa, while the electron density between the bonded atoms increases by 0.12 and 0.15 e/Å3, on average. The calculations also show that the coordination number of the Y atom increases from 9 to 10 while the coordination number of the O1 atom increases concomitantly in the structure from 5 to 6 at 20 GPa. Hence pressure not only promotes an increase in the coordination number of the metal atoms but also a necessary concomitant increase in the coordination number of the O atoms. The bonded radii, determined at a lower pressure between 0.0 and 15 GPa for LaAlO3 and CaSnO3, decrease a smaller amount with the radii for the La and Ca atoms decreasing by 0.03 and 0.04 Å, respectively, while the radii for the smaller Al and Sn atoms decrease by 0.01 and 0.02 Å, respectively. In general, O atoms are more compressible than the metal atoms, but overall the calculations demonstrate that the bonded radii for the atoms in crystals are virtually incompressible when subjected to high pressure. The reason that the bonded radii change little when subjected to high pressure is ascribed to the changes in the effective interatomic potentials that result in increased repulsion when the atoms are squeezed together.

  PublisherDOI

• Oxidation of MnO(100) and NaMnO2 formation: Characterization of Mn2+ and Mn3+ surfaces via XPS and water TPD

  Surface Science · 2018-04-30 · 46 citations

  articleSenior authorCorresponding
  PublisherDOI

• Sulfide bonded atomic radii

  Physics and Chemistry of Minerals · 2017-03-15 · 8 citations

  articleSenior authorCorresponding
  PublisherDOI

• Na Deposition on MnO(100)

  Surface Science · 2015-11-04 · 15 citations

  articleOpen accessSenior authorCorresponding
  PublisherOA PDFDOI

Frequent coauthors

• G. V. Gibbs

  Virginia Tech

  131 shared

• Nancy L. Ross

  109 shared

• Robert T. Downs

  University of Arizona

  99 shared

• Kevin M. Rosso

  Pacific Northwest National Laboratory

  87 shared

• K. M. Rosso

  46 shared

• A. F. Wallace

  Duke University

  36 shared

• M. B. Boisen

  University of Idaho

  28 shared

• Mark A. Spackman

  University of Western Australia

  25 shared

Education

• Ph.D., Chemical Engineering

  University of Florida

  1984