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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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r describes how an iterative repair planner/scheduler can reason about the activities of multiple spacecraft at abstract levels in order to greatly improve the scheduling of their use of shared resources.
r describes a way to schedule high level activities before distributing them across multiple rovers in order to coordinate the resultant use of shared resources regardless of how each rover decides how to perform its activities. We present an algorithm for summarizing the metric resource requirements of an abstract activity based n the resource usages of its potential refinements.
t an algorithm for summarizing the metric resource requirements of an abstract activity based on the resource usages of its potential refinements.
There are many compounds for which OH abstraction rate constants may be required.
Initial CRADA abstract required for publication per DOE O 483.1B for Umbrella CRADA with Texas Tech University
Abstract for Joint Work Statement MSTS-2023-01U-JWS-01 to investigate creation of synthetic melt glass for nuclear attribution. Work is to be completed under approved CRADA MSTS-2023-01U with UNLV.
Abstract for public release to satisfy requirements of Copyright Assertion as outlined in our Prime Contract with DOE/NNSA. Approval for copyright assertion was received by HQ on 9/30/2024
Initial abstract for umbrella CRADA with University of Nevada, Reno.
CRADA abstract suitable for publication to meet the requirements of DOE O 483.1B.
CRADA abstract suitable for publication to meet the requirements of DOE O 483.1B.
Abstract for CRADA with Aura Network Services
Abstract for CRADA with University of Missouri
CRADA abstract for publication as required by DOE O 483.1B
Abstract for CRADA MSTS-2025-08M with Kansas State University
Polycyclic aromatic hydrocarbons (PAHs) are omnipresent in the interstellar medium (ISM) and also in carbonaceous meteorites (CM) such as Murchison. However, the basic reaction routes leading to the formation of even the simplest PAH—naphthalene (C 10 H 8 )—via the hydrogen-abstraction/acetylene-addition (HACA) mechanism still remain ambiguous. Here, by revealing the uncharted fundamental chemistry of the styrenyl (C 8 H 7 ) and the ortho-vinylphenyl radicals (C 8 H 7 )—key transient species of the HACA mechanism—with acetylene (C 2 H 2 ), we provide the first solid experimental evidence on the facile formation of naphthalene in a simulated combustion environment validating the previously postulated HACA mechanism for these two radicals. Lastly, this study highlights, at the molecular level spanning combustion and astrochemistry, the importance of the HACA mechanism to the formation of the prototype PAH naphthalene.
Catalysts for the oxidation of NH 3 will be critical to utilize NH 3 as a large-scale energy carrier. Molecular complexes have not been shown to catalyze the oxidation of NH 3 to N 2 . We report Ru- catalyzed oxidation of ammonia to dinitrogen under ambient conditions using the molecular complex [Cp*Ru(P t Bu 2 N Ph 2 )( 15 NH 3 )][BAr F 4 ]. Mediating the cleavage of six N-H bonds and the formation of an N≡N bond was achieved by coupling H + and e - transfers as net hydrogen atom abstraction steps using the 2,4,6-tri- t ert-butylphenoxyl radical ( t Bu 3 ArO•) as the H atom acceptor. Employing an excess of t Bu 3 ArO• under 1 atm of NH 3 gas at 23 °C resulted in up to six turnovers. As a result, nitrogen isotopic ( 15 N) labeling studies provide mechanistic insights to confirm the N≡N bond forming step in the catalytic cycle.
The silylium-like surface species [ i Pr 3 Si][(R F O) 3 Al-OSi≡)] activates (N^N)Pd(CH 3 )Cl (N^N=Ar-N=CMeMeC=N-Ar, Ar=2,6-bis(diphenylmethyl)-4-methylbenzene) by chloride ion abstraction to form [(N^N)Pd-CH 3 ][(R F O) 3 Al-OSi≡)] ( 1 ). A combination of FTIR, solid-state NMR spectroscopy, and reactions with CO or vinyl chloride establish that 1 shows similar reactivity patterns as (N^N)Pd(CH 3 )Cl activated with Na[B(Ar F ) 4 ]. Multinuclear 13 C{ 27 Al} RESPDOR and 1 H{ 19 F} S-REDOR experiments are consistent with a weakly coordinated ion-pair between (N^N)Pd-CH 3 + and [(R F O) 3 Al-OSi≡)]. 1 catalyzes the polymerization of ethylene with similar activities as [(N^N)Pd-CH 3 ] + in solution and incorporates up to 0.4% methyl acrylate in copolymerization reactions. 1 produces polymers with significantly higher molecular weight than the solution catalyst, and generates the highest molecular weight polymers currently reported in copolymerization reactions of ethylene and methylacrylate.
The kinetics of the reaction of benzyl radicals with [L{sup 1}(H{sub 2}O)RhH{l_brace}D{r_brace}]{sup 2+} (L{sup 1}=1,4,8,11-tetraazacyclotetradecane) were studied directly by laser-flash photolysis. The rate constants for the two isotopologues, k=(9.3 {+-} 0.6) x 10{sup 7} M{sup -1} s{sup -1} (H) and (6.2 {+-} 0.3) x 10{sup 7} M{sup -1} s{sup -1} (D), lead to a kinetic isotope effect k{sub H}/k{sub D}=1.5 {+-} 0.1. The same value was obtained from the relative yields of PhCH{sub 3} and PhCH{sub 2}D in a reaction of benzyl radicals with a mixture of rhodium hydride and deuteride. Similarly, the reaction of methyl radicals with {l_brace}[L{sup 1}(H{sub 2}O)RhH]{sup 2+} + [L{sup 1}(H{sub 2}O)RhD]{sup 2+}{r_brace} produced a mixture of CH{sub 4} and CH{sub 3}D that yielded k{sub H}/k{sub D}=1.42 {+-} 0.07. The observed small normal isotope effects in both reactions are consistent with reduced sensitivity to isotopic substitution in very fast hydrogen-atom abstraction reactions. These data disprove a literature report claiming much slower kinetics and an inverse kinetic isotope effect for the reaction of methyl radicals with hydrides of L{sup 1}Rh.