Publications

Celina, Mathias C.; Grubelich, Mark C.; Knudsen, Steven D.; Thoma, Steven T.

Abstract not provided.

Grubelich, Mark C.; Thoma, Steven T.

Abstract not provided.

Villone, J.; Yang, Pin Y.; Doty, Fred P.; Thoma, Steven T.; Boyle, Timothy J.; Steele, Leigh A.; Hernandez-Sanchez, Bernadette A.

Abstract not provided.

Yang, Pin Y.; Doty, Fred P.; Thoma, Steven T.; Boyle, Timothy J.; Steele, Leigh A.; Hernandez-Sanchez, Bernadette A.

Abstract not provided.

Gupta, Vipin P.; Celina, Mathias C.; Thoma, Steven T.

The U.S. is addicted to petroleum--a dependency that periodically shocks the economy, compromises national security, and adversely affects the environment. If liquid fuels remain the main energy source for U.S. transportation for the foreseeable future, the system solution is the production of new liquid fuels that can directly displace diesel and gasoline. This study focuses on advanced concepts for biofuel factory production, describing three design concepts: biopetroleum, biodiesel, and higher alcohols. A general schematic is illustrated for each concept with technical description and analysis for each factory design. Looking beyond current biofuel pursuits by industry, this study explores unconventional feedstocks (e.g., extremophiles), out-of-favor reaction processes (e.g., radiation-induced catalytic cracking), and production of new fuel sources traditionally deemed undesirable (e.g., fusel oils). These concepts lay the foundation and path for future basic science and applied engineering to displace petroleum as a transportation energy source for good.

Wilcoxon, Jess P.; Thoma, Steven T.; Abrams, B.L.

Abstract not provided.

Journal of Physical Chemistry B

Abrams, B.L.; Wilcoxon, Jess P.; Thoma, Steven T.

Abstract not provided.

Simmons, J.A.; Fischer, Arthur J.; Crawford, Mary H.; Abrams, B.L.; Biefeld, Robert M.; Koleske, Daniel K.; Allerman, A.A.; Figiel, J.J.; Creighton, J.R.; Coltrin, Michael E.; Tsao, Jeffrey Y.; Mitchell, Christine C.; Kerley, Thomas M.; Wang, George T.; Bogart, Katherine B.; Seager, Carleton H.; Campbell, Jonathan C.; Follstaedt, D.M.; Norman, Adam K.; Kurtz, S.R.; Wright, Alan F.; Myers, S.M.; Missert, Nancy A.; Copeland, Robert G.; Provencio, P.N.; Wilcoxon, Jess P.; Hadley, G.R.; Wendt, J.R.; Kaplar, Robert K.; Shul, Randy J.; Rohwer, Lauren E.; Tallant, David T.; Simpson, Regina L.; Moffat, Harry K.; Salinger, Andrew G.; Pawlowski, Roger P.; Emerson, John A.; Thoma, Steven T.; Cole, Phillip J.; Boyack, Kevin W.; Garcia, Marie L.; Allen, Mark S.; Burdick, Brent B.; Rahal, Nabeel R.; Monson, Mary A.; Chow, Weng W.; Waldrip, Karen E.

This SAND report is the final report on Sandia's Grand Challenge LDRD Project 27328, 'A Revolution in Lighting -- Building the Science and Technology Base for Ultra-Efficient Solid-state Lighting.' This project, which for brevity we refer to as the SSL GCLDRD, is considered one of Sandia's most successful GCLDRDs. As a result, this report reviews not only technical highlights, but also the genesis of the idea for Solid-state Lighting (SSL), the initiation of the SSL GCLDRD, and the goals, scope, success metrics, and evolution of the SSL GCLDRD over the course of its life. One way in which the SSL GCLDRD was different from other GCLDRDs was that it coincided with a larger effort by the SSL community - primarily industrial companies investing in SSL, but also universities, trade organizations, and other Department of Energy (DOE) national laboratories - to support a national initiative in SSL R&D. Sandia was a major player in publicizing the tremendous energy savings potential of SSL, and in helping to develop, unify and support community consensus for such an initiative. Hence, our activities in this area, discussed in Chapter 6, were substantial: white papers; SSL technology workshops and roadmaps; support for the Optoelectronics Industry Development Association (OIDA), DOE and Senator Bingaman's office; extensive public relations and media activities; and a worldwide SSL community website. Many science and technology advances and breakthroughs were also enabled under this GCLDRD, resulting in: 55 publications; 124 presentations; 10 book chapters and reports; 5 U.S. patent applications including 1 already issued; and 14 patent disclosures not yet applied for. Twenty-six invited talks were given, at prestigious venues such as the American Physical Society Meeting, the Materials Research Society Meeting, the AVS International Symposium, and the Electrochemical Society Meeting. This report contains a summary of these science and technology advances and breakthroughs, with Chapters 1-5 devoted to the five technical task areas: 1 Fundamental Materials Physics; 2 111-Nitride Growth Chemistry and Substrate Physics; 3 111-Nitride MOCVD Reactor Design and In-Situ Monitoring; 4 Advanced Light-Emitting Devices; and 5 Phosphors and Encapsulants. Chapter 7 (Appendix A) contains a listing of publications, presentations, and patents. Finally, the SSL GCLDRD resulted in numerous actual and pending follow-on programs for Sandia, including multiple grants from DOE and the Defense Advanced Research Projects Agency (DARPA), and Cooperative Research and Development Agreements (CRADAs) with SSL companies. Many of these follow-on programs arose out of contacts developed through our External Advisory Committee (EAC). In h s and other ways, the EAC played a very important role. Chapter 8 (Appendix B) contains the full (unedited) text of the EAC reviews that were held periodically during the course of the project.

Proposed for publication in Chemistry of Materials.

Thoma, Steven T.; Thoma, Steven T.; Bonhomme, F.; Cygan, Randall T.

A novel layered manganese(II) phosphate, Mn{sub 3}(PO{sub 4}){sub 4} {center_dot} 2(H{sub 3}NCH{sub 2}CH{sub 2}){sub 3}N {center_dot} 6(H{sub 2}O), has been synthesized solvothermally using tris(2-aminoethyl)amine (TREN) as a template. The structure was solved ab initio using X-ray powder diffraction data and confirmed by molecular modeling. The compound was further characterized by SEM, IR spectroscopy, photoluminescence, and elemental and thermal analysis. The compound crystallizes in the trigonal space group P{sub 3}c1 with a = 8.8706(4) {angstrom}, c = 26.158(2) {angstrom}, and V = 1782.6(2) {angstrom}{sup 3}. The structure consists of layers of corner sharing Mn(II)O{sub 4} and PO{sub 4} tetrahedra forming infinite [Mn{sub 3}(PO{sub 4}){sub 4}]{sup 6-} macroanions with 4.6 net topology, sandwiched by layers of TREN and water molecules. The protonated TREN molecules provide charge balancing for the inorganic sheets; the interlayer stability is accomplished mainly by a network of hydrogen bonds between water molecules and the inorganic macroanions. This hybrid organic/inorganic layered material can be reversibly dehydrated.

Giunta, Rachel K.; Thoma, Steven T.; Giunta, Rachel K.; Stavig, Mark E.; Emerson, John A.; Morales, Alfredo M.

The autonomic healing ability of an epoxy adhesive containing micro-encapsulated dicyclopentadiene (DCPD) was evaluated. The epoxy resin used was Epon 828 cured with either Versamid 140 or diethylenetriamine (DETA). Variables included total weight percent of microcapsules (MCs) and catalyst, as well as the catalyst to DCPD ratio. The degree of healing was determined by the fracture toughness before and after ''healing'' using double-cantilever beam analysis. It was found that the degree of self-healing was most directly related to the contact area (i.e. crack width) during healing. Temperature also played a significant role. Observed differences between the results of this study and those in literature are discussed.

Journal of Fluorine Chemistry

Thoma, Steven T.; Bonhomme, F.; Nyman, M.; Rodriguez, Marko A.; Nenoff, T.M.; Nenoff, T.M.

Abstract not provided.

Microporous and Mesoporous Materials Journal

Thoma, Steven T.; Nenoff, T.M.; Nenoff, T.M.

A study of zeolite crystallization from sol-gel precursors using the vapor phase transport synthesis method has been performed. Zeolites (ZSM-5, ZSM-48, Zeolite P, and Sodalite) were crystallized by contacting vapor phase organic or organic-water mixtures with dried sodium silicate and dried sodium alumino-silicate gels. For each precursor gel, a ternary phase system of vapor phase organic reactant molecules was explored. The vapor phase reactant mixtures ranged from pure ethylene diamene, triethylamine, or water, to an equimolar mixture of each. In addition, a series of gels with varied physical and chemical properties were crystallized using the same vapor phase solvent mixture for each gel. The precursor gels and the crystalline products were analyzed via Scanning Electron Microscopy, Electron Dispersive Spectroscopy, X-ray mapping, X-ray powder diffraction, nitrogen surface area, Fourier Transform Infrared Spectroscopy, and thermal analyses. The product phase and purity as a function of the solvent mixture, precursor gel structure, and precursor gel chemistry is discussed.