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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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Activating and optimizing MoS2 basal planes for hydrogen evolution through the formation of strained sulphur vacancies
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Compressed glassy carbon maintaining graphite-like structure with linkage formation between graphene layers
Abstract not provided
Formation of Nanofoam carbon and re-emergence of Superconductivity in compressed CaC6
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Oxide Enthalpy of Formation and Band Gap Energy as Accurate Descriptors of Oxygen Vacancy Formation Energetics
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Nickel Oxide Interlayer Films from Nickel Formate-Ethylenediamine Precursor: Influence of Annealing on Thin Film Properties and Photovoltaic Device Performance
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Facile incorporation of technetium into magnetite, magnesioferrite, and hematite by formation of ferrous nitrate in situ : precursors to iron oxide nuclear waste forms
The fission product, 99 Tc, presents significant challenges to the long-term disposal of nuclear waste due to its long half-life, high fission yield, and to the environmental mobility of pertechnetate (TcO 4 – ), the stable Tc species in aerobic environments. Here, the migration of 99 Tc from disposal sites can potentially be prevented by incorporating it into durable waste forms based on environmentally stable minerals.
Tuning two-dimensional phase formation through epitaxial strain and growth conditions: silica and silicate on Ni x Pd 1−x (111) alloy substrates
The combined experimental and theoretical results demonstrate the manipulation of 2D VDW silica and 2D Ni silicate through growth conditions, and the determination of the maximum epitaxial strain imparted to the 2D system through alloy substrate.
Control of formation of viscoelastic droplets and distribution of nano-inclusions in functional deposition for lithium–sulfur batteries
The electrospray process produces micro/nanodroplets for various applications such as thin and uniform coatings, drug carriers and mass spectrometry. In this paper, we study the spray processes of viscoelastic jets using simulations and experiments. In discretized modeling, the jet is perturbed with axisymmetric instability and the growth of this instability causes the jet to break into droplets. For the experiments, a solution of polyvinyl alcohol in water is sprayed and is visualized using a high-speed camera. The droplet size distribution is studied from simulations with experiments for three spray cases: electrospray, air spray, and air-controlled electrospray. Our simulations and experiments reveal that the electric field is effective in reducing the droplet size, while air flow offers more jet break-ups and thus a larger number of droplets. As a result, air-controlled electrospray where these two driving forces are synergistically combined leads to a larger number of smaller droplets than electrospray or air spray. As a result, we applied three spray processes to obtain a deposition of sulfur/mesoporous carbon/graphene/polymer binder composites as a lithium sulfur battery cathode and demonstrated that air-controlled electrospray leads to a higher capacity and rate capability than other processes, exhibiting 800 mA h g –1 at 0.5C and 600 mA h g –1 at 2C.
Characterization of the Alkali Metal Oxalates (MC2O4-) and their formation by CO2 reduction via the Alkali Metal Carbonites (MCO2-)
The reduction of carbon dioxide to oxalate has been studied by experimental Collisionally Induced Dissociation (CID) and vibrational characterization of the alkali metal oxalates, supplemented by theoretical electronic structure calculations. The critical step in the reductive process is the coordination of the heterocumulene CO2 to an alkali metal anion, forming a metal carbonite MCO2 ablt to subsequently add a second CO2 molecule. While the energetic demand for these reactions is generally low, we find that the degree of activation of CO2 in terms of charge transfer and transition state energies is the highest for lithium and systematically decreases down the group (M - Li - Cs).
Boronic, diboronic and boric acid esters of 1,8-naphthalenediol – synthesis, structure and formation of boronium salts
New 1,8-naphthalenediolate supported boronic, diboronic and boric acid esters and boronium salts have been synthesized and structurally characterized.
Effect of Impurities on Radical Formation in Gibbsite Radiolysis
The generation and stabilization of gamma radiation-induced hydrogen atoms in gibbsite (Al(OH)3) nanoplates is directly related to the nature of residual ions from synthetic precursors used, whether nitrates or chlorides. The concentration of hydrogen atoms trapped in the interstitial layers of gibbsite is lower and decays faster in comparison to boehmite (AlOOH), which could affect the waste management of these materials.
Formation, characterization, and dynamics of onion-like carbon structures for electrical energy storage from nanodiamonds using reactive force fields
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Kinetics of color center formation in silica irradiated with swift heavy ions: Thresholding and formation efficiency
We have determined the cross-section {sigma} for color center generation under single Br ion impacts on amorphous SiO{sub 2}. The evolution of the cross-sections, {sigma}(E) and {sigma}(S{sub e}), show an initial flat stage that we associate to atomic collision mechanisms. Above a certain threshold value (S{sub e} > 2 keV/nm), roughly coinciding with that reported for the onset of macroscopic disorder (compaction), {sigma} shows a marked increase due to electronic processes. In this regime, a energetic cost of around 7.5 keV is necessary to create a non bridging oxygen hole center-E Prime (NBOHC/E Prime ) pair, whatever the input energy. The data appear consistent with a non-radiative decay of self-trapped excitons.
Polaron formation: Ehrenfest dynamics vs. exact results
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Liquid-crystal mediated nanoparticle interactions and gel formation
Colloidal particles embedded within nematic liquid crystals exhibit strong anisotropic interactions arising from preferential orientation of nematogens near the particle surface. Such interactions are conducive to forming branched, gel-like aggregates. Anchoring effects also induce interactions between colloids dispersed in the isotropic liquid phase, through the interactions of the pre-nematic wetting layers. Here we utilize computer simulation using coarse-grained mesogens to perform a molecular-level calculation of the potential of mean force between two embedded nanoparticles as a function of anchoring for a set of solvent conditions straddling the isotropic–nematic transition. We observe that strong, nontrivial interactions can be induced between particles dispersed in mesogenic solvent, and explore how such interactions might be utilized to induce a gel state in the isotropic and nematic phases.
The interaction of 193 nm excimer laser radiation with single-crystal zinc oxide: Generation of long lived highly excited particles with evidence of Zn Rydberg formation
In past studies, we have observed copious emissions of ionic and atomic Zn from single-crystal ZnO accompanying irradiation of single-crystal ZnO with 193-nm excimer laser irradiation at fluences below the onset of optical breakdown. The Zn{sup +} and ground state Zn° are studied using time-of-flight techniques and are mass selected using a quadrupole mass spectrometer. Simultaneously, we have observed emitted particles that are detectable with a Channeltron electron multiplier but cannot be mass selected. It is a reasonable hypothesis that these particles correspond to a neutral atom or molecule in highly excited long lived states. We provide strong evidence that they correspond to high lying Rydberg states of atomic Zn. We propose a production mechanism involving laser excitation via a two photon resonance excitation of Zn°.