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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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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on AsSe by Materials Project

AsSe is BCT5-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four AsSe clusters. there are four inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in an L-shaped geometry to two Se2- atoms. Both As–Se bond lengths are 2.41 Å. In the second As2+ site, As2+ is bonded in an L-shaped geometry to two Se2- atoms. Both As–Se bond lengths are 2.41 Å. In the third As2+ site, As2+ is bonded in an L-shaped geometry to two Se2- atoms. Both As–Se bond lengths are 2.41 Å. In the fourth As2+ site, As2+ is bonded in an L-shaped geometry to two Se2- atoms. Both As–Se bond lengths are 2.40 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a water-like geometry to two As2+ atoms. In the second Se2- site, Se2- is bonded in a water-like geometry to two As2+ atoms. In the third Se2- site, Se2- is bonded in a water-like geometry to two As2+ atoms. In the fourth Se2- site, Se2- is bonded in a water-like geometry to two As2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsS(IF3)2 by Materials Project

AsS(IF3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent As2- sites. In the first As2- site, As2- is bonded in an octahedral geometry to six F1- atoms. There is two shorter (1.77 Å) and four longer (1.78 Å) As–F bond length. In the second As2- site, As2- is bonded in an octahedral geometry to six F1- atoms. There is four shorter (1.77 Å) and two longer (1.79 Å) As–F bond length. S2- is bonded in a 5-coordinate geometry to one S2-, two I5+, and three F1- atoms. The S–S bond length is 1.86 Å. There are one shorter (2.86 Å) and one longer (3.24 Å) S–I bond lengths. There are a spread of S–F bond distances ranging from 2.98–3.32 Å. There are two inequivalent I5+ sites. In the first I5+ site, I5+ is bonded in a distorted single-bond geometry to one S2-, one I5+, and one F1- atom. The I–I bond length is 2.63 Å. The I–F bond length is 2.89 Å. In the second I5+ site, I5+ is bonded in an L-shaped geometry to one S2- and one I5+ atom. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As2- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As2- atom. In the third F1- site, F1- is bonded in a single-bond geometry to one As2- and one S2- atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one As2- and one S2- atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one As2- and one I5+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one As2- and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Nanosecond carrier lifetimes in solution-processed enargite (Cu 3 AsS 4 ) thin films

Enargite (ENG) Cu 3 AsS 4 is a promising material for photovoltaic applications due to its constituent earth abundant elements of differing ionic radii, ideal predicted optoelectronic properties, and demonstrated use in a working thin-film solar cell. However, little is known about ENG's defect properties; such knowledge is necessary to assess its potential for future use in high-efficiency devices. One indicator of a material's quality is its photogenerated carrier lifetime, which can be related to its bulk defect properties. Here, we use a combination of time-resolved terahertz spectroscopy and time-resolved photoluminescence to assess carrier dynamics in ENG thin films processed from nanoparticle precursors. The Shockley–Read–Hall (SRH) lifetimes are on the multi-nanosecond scale, which exceed those reported in more mature systems and represent promising values for a candidate photovoltaic material. These results suggest that ENG is worthy of further research and development effort with an eye toward future photovoltaic applications.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Materials Data on AsS by Materials Project

SAs is alpha Selenium-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four tetraarsenic tetrasulfide molecules. there are four inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.26 Å. In the second As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.26 Å) and one longer (2.27 Å) As–S bond lengths. In the third As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.25 Å. In the fourth As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.26 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to two As2+ atoms. In the second S2- site, S2- is bonded in a water-like geometry to two As2+ atoms. In the third S2- site, S2- is bonded in a water-like geometry to two As2+ atoms. In the fourth S2- site, S2- is bonded in a water-like geometry to two As2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsS by Materials Project

SAs crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of four tetraarsenic tetrasulfide molecules. there are two inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. Both As–S bond lengths are 2.26 Å. In the second As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.25 Å) and one longer (2.26 Å) As–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to two equivalent As2+ atoms. In the second S2- site, S2- is bonded in a water-like geometry to two equivalent As2+ atoms. In the third S2- site, S2- is bonded in a water-like geometry to two As2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsS by Materials Project

SAs is High Pressure (4-7GPa) Tellurium-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four SAs clusters. there are four inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in a distorted trigonal non-coplanar geometry to three S2- atoms. There are a spread of As–S bond distances ranging from 2.28–2.30 Å. In the second As2+ site, As2+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.27 Å) and one longer (2.30 Å) As–S bond lengths. In the third As2+ site, As2+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.22 Å. In the fourth As2+ site, As2+ is bonded in a water-like geometry to two S2- atoms. There are one shorter (2.27 Å) and one longer (2.30 Å) As–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in an L-shaped geometry to two As2+ atoms. In the second S2- site, S2- is bonded in a water-like geometry to two As2+ atoms. In the third S2- site, S2- is bonded in a water-like geometry to two As2+ atoms. In the fourth S2- site, S2- is bonded in a water-like geometry to two As2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsS by Materials Project

SAs crystallizes in the orthorhombic Cmc2_1 space group. The structure is one-dimensional and consists of two SAs ribbons oriented in the (0, 0, 1) direction. there are two inequivalent As2+ sites. In the first As2+ site, As2+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of As–S bond distances ranging from 2.44–2.93 Å. In the second As2+ site, As2+ is bonded in an L-shaped geometry to two S2- atoms. There are one shorter (2.29 Å) and one longer (2.36 Å) As–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to four As2+ atoms to form distorted corner-sharing SAs4 trigonal pyramids. In the second S2- site, S2- is bonded in a 2-coordinate geometry to three As2+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1989

Use of satellite data and modeling to asses the influence of stratospheric processes on the troposphere

The research is comprised of the following tasks: use of simple analytical and numerical models of a coupled troposphere-stratosphere system to examine the effects of radiation and ozone on planetary wave dynamics and the tropospheric circulation; use of satellite data obtained from the Nimbus 7 Limb Infrared Monitor of the Stratosphere (LIMS) instrument and Solar Backscattered Ultraviolet (SBUV) experiment, in conjunction with National Meteorological Center (NMC) data, to determine the planetary wave vertical structures, dominant wave spectra, ozone spectra, and time variations in diabatic heating rate; and synthesis of the modeling and observational results to provide a better understanding of the effects that stratospheric processes have on tropospheric dynamics.

Nathan, Terrence R.↗
DOE OSTI2021

Structure Tuning, Strong Second Harmonic Generation Response, and High Optical Stability of the Polar Semiconductors Na 1- x K x AsQ 2

We report the mixed cation compounds Na 1-x K x AsSe 2 (x = 0.8, 0.65, 0.5) and Na 0.1 K 0.9 AsS 2 crystallize in the polar noncentrosymmetric space group Cc. The AAsQ(2) (A = alkali metals, Q = S, Se) family features one-dimensional (1D) 1 / ∞ [AQ 2 - ] chains comprising corner-sharing pyramidal AQ 3 units in which the packing of these chains is dependent on the alkali metals. The parallel 1 / ∞ [AQ(2) - ] chains interact via short As ∙∙∙Se contacts, which increase in length when the fraction of K atoms is increased. The increase in the As ∙∙∙Se interchain distance increases the band gap from 1.75 eV in γ-NaAsSe 2 to 2.01 eV in Na 0.35 K 0.65 AsSe 2 , 2.07 eV in Na 0.2 K 0.8 AsSe 2 , and 2.18 eV in Na 0.1 K 0.9 AsS 2 . The Na 1-x K x AsSe 2 (x = 0.8, 0.65) compounds melt congruently at approximately 316 °C. Wavelength-dependent second harmonic generation (SHG) measurements on powder samples of Na 1-x K x AsSe 2 (x = 0.8, 0.65, 0.5) and Na 0.1 K 0.9 AsS 2 suggest that Na 0.2 K 0.8 AsSe 2 and Na 0.1 K 0.9 AsS 2 have the highest SHG response and exhibit significantly higher laser-induced damage thresholds (LIDTs). Theoretical SHG calculations on Na 0.5 K 0.5 AsSe 2 confirm its SHG response with the highest value of d 33 = 22.5 pm/V χ 333 (2) = 45.0 pm/V). The effective nonlinearity for a randomly oriented powder is calculated to be d eff = 18.9 pm/V χ eff (2) = 37.8 pm/V), which is consistent with the experimentally obtained value of d eff = 16.5 pm/V χ eff (2) = 33.0 pm/V). Three-photon absorption is the dominant mechanism for the optical breakdown of the compounds under intense excitation at 1580 nm, with Na 0.2 K 0.8 AsSe 2 exhibiting the highest stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1993

Integrating payload design, planning, and control in the Dutch Utilisation Centre

Spacecraft payload design, experiment planning and scheduling, and payload control are traditionally separate areas of activity. This paper describes the development of a prototype software tool--the Activity Scheduling System (ASS)--which integrates these activity areas. ASS is part of a larger project to build a Dutch Utilisation Centre (DUC), intended eventually to support all space utilization activities in The Netherlands. ASS has been tested on the High Performance Capillary Electrophoresis payload. The paper outlines the integrated preparation and operations concept embodied in ASS. It describes the ASS prototype, including a typical session. The results of testing are summarized. Possible enhancement of ASS, including integration into DUC, is sketched.

Grant, T. J.↗
DOE OSTI2024

Strategies to Obtain Reliable Energy Landscapes from Embedded Multireference Correlated Wavefunction Methods for Surface Reactions

Embedded correlated wavefunction (ECW) theory is a powerful tool for studying ground- and excited-state reaction mechanisms and associated energetics in heterogeneous catalysis. Several factors are important to obtaining reliable ECW energies, critically the construction of consistent active spaces (ASs) along reaction pathways when using a multireference correlated wavefunction (CW) method that relies on a subset of orbital spaces in the configuration interaction expansion to account for static electron correlation, e.g., complete AS self-consistent field theory, in addition to the adequate partitioning of the system into a cluster and environment, as well as the choice of a suitable basis set and number of states included in excited-state simulations. Here, in this work, we conducted a series of systematic studies to develop best-practice guidelines for ground- and excited-state ECW theory simulations, utilizing the decomposition of NH 3 on Pd(111) as an example. We determine that ECW theory results are relatively insensitive to cluster size, the aug-cc-pVDZ basis set provides an adequate compromise between computational complexity and accuracy, and that a fixed-clean-surface approximation holds well for the derivation of the embedding potential. Additionally, we demonstrate that a merging approach, which involves generating ASs from the molecular fragments at each configuration, is preferable to a creeping approach, which utilizes ASs from adjacent structures as an initial guess, for the generation of consistent potential energy curves involving open-d-shell metal surfaces, and, finally, we show that it is essential to include bands of excited states in their entirety when simulating excited-state reaction pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Bridging adsorption behavior of confined CH 4 -CO 2 binary mixtures across scales

An accurate understanding of the competitive adsorption of CH 4 -CO 2 binary mixtures in nano-confined systems is critical for engineering CO 2 storage in shale gas reservoirs. Due to difficulties in making reliable experimental observations in nano-scale, atomistic simulations (ASs), such as the Grand Canonical Monte Carlo (GCMC) method, provide a viable approach to studying the adsorption behavior of confined fluids. ASs are, however, limited in the size of the compositional domain due to the high computational cost. This work proposes a framework that combines AS and the lattice Boltzmann (LB) method to bridge the physics of confined fluids across scales. The Peng–Robinson equation of state (PR-EoS) produces fugacity coefficients, which serve as input for conducting multi-component GCMC simulations. These GCMC simulations explore the competitive adsorption behavior of CH 4 -CO 2 in nano-slits at various composition, pressure, and channel-width conditions. Both components generate adsorption layers with high densities near the walls with CO 2 preferentially adsorbing compared to CH 4 on the organic walls of carbon sheets. At the mesoscale, a pseudopotential model represents the intermolecular forces in multi-component, multiple-relaxation-time LB simulations. The LB simulations are in good agreement with the GCMC results, allowing us to obtain values for tunable LB parameters. We then extend the use of LB to simulate adsorption behavior in complex networks with nano-sized channels. The phase behavior and fluid properties in the complex geometries of nano-channels differ from nano-slits and bulk systems. Furthermore, the bridging of physics from GCMC (microscale) to LB (mesoscale) via the macroscale PR-EoS connects the adsorption behavior of binary systems across scales.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Elastic NaxMoS2-carbon-BASE triple interface direct robust solid-solid interface for all-solid-state Na-S batteries

The promises of all-solid-state (ASS) sodium batteries for the next generation energy storage are widely recognized but their developments have been severely constrained by the difficulties to design favorable solid-solid interfaces for unhindered Na-ion transport. Using the most promising ß?-Al2O3 solid state electrolyte (BASE) as a platform, we demonstrate here a triple nanojunction strategy that provides simultaneous strong Na adhesion and continuous Na-ions diffusion at solid-solid interface. Such triple junctions (NaxMoS2-carbon-BASE) were constructed by adhering ternary composite Na anodes containing dispersed 3 wt% MoS2 and 3 wt% carbon on BASE, and provide nearly complete adhesion of Na on BASE with a much smaller contact angle (~ 45o vs. 120o of pristine Na). The composite Na anodes exhibited ~ 3 times improved elastic property and the synergy of NaxMoS2 and carbon provides the required ionic and electronic diffusion channels at solid-solid interface, which significantly improve Na utilization and resist premature failure due to loss of solid-solid contact as Na shrink during high capacity stripping. As a result, Na metal at the triple junction exhibited more than five time reduced charge transfer resistance and at least 200 hours stable battery cycling at practical current densities. The novel anode architecture also enabled high capacity cycling of prototype ASS sodium sulfur batteries when coupled with advanced sulfur cathodes containing intrinsic Na-ions diffusion channels and redox catalytic mediators, leading to stable cycling with specific capacity of 1110 mAh g-1.

ß”-Al2O3 solid electrolyte, solid state batteries,↗
DOE OSTI2023

A Distributionally Robust Resilience Enhancement Strategy for Distribution Networks Considering Decision-Dependent Contingencies

When performing the resilience enhancement for distribution networks, there are two obstacles to reliably model the uncertain contingencies: 1) decision-dependent uncertainty (DDU) due to various line hardening decisions, and 2) distributional ambiguity due to limited outage information during extreme weather events (EWEs). Here, to address these two challenges, this paper develops scenario-wise decision-dependent ambiguity sets (SWDD-ASs), where the DDU and distributional ambiguity inherent in EWE-induced contingencies are simultaneously captured for each possible EWE scenario. Then, a two-stage tri-level decision-dependent distributionally robust resilient enhancement (DD-DRRE) model is formulated, whose outputs include the optimal line hardening, distributed generation (DG) allocation, and proactive network reconfiguration strategy under the worst-case distributions in SWDD-ASs. Subsequently, the DD-DRRE model is equivalently recast to a mixed-integer linear programming (MILP)-based master problem and multiple scenario-wise subproblems, facilitating the adoption of a customized column-and-constraint generation (C&CG) algorithm. Finally, case studies demonstrate a remarkable improvement in the out-of-sample performance of our model, compared to its prevailing stochastic and robust counterparts. Moreover, the potential values of incorporating the ambiguity and distributional information are quantitatively estimated, providing a useful reference for planners with different budgets and risk-aversion levels.

decision-dependent uncertainty↗
DOE OSTI2025

Peening Techniques for Mitigating Chlorine-Induced Stress Corrosion Cracking of Dry Storage Canisters for Nuclear Applications

Fusion-welded austenitic stainless steel (ASS) was predominantly employed to manufacture dry storage canisters (DSCs) for the storage applications of spent nuclear fuel (SNF). However, the ASS weld joints are prone to chloride-induced stress corrosion cracking (CISCC), a critical safety issue in the nuclear industry. DSCs were exposed to a chloride-rich environment during storage, creating CISCC precursors. The CISCC failure leads to nuclear radiation leakage. Therefore, there is a critical need to enhance the CISCC resistance of DSC weld joints using promising repair techniques. This review article encapsulates the current state-of-the-art of peening techniques for mitigating the CISCC in DSCs. More specifically, conventional shot peening (CSP), ultrasonic impact peening (UIP), and laser shock peening (LSP) were elucidated with a focus on CISCC mitigation. The underlying mechanism of CISCC mitigation in each process was summarized. Finally, this review provides recent advances in surface modification techniques, repair techniques, and developments in welding techniques for CISCC mitigation in DSCs.

Chemistry↗
DOE OSTI2020

An Overview of R and D on Retrievability and Retrieval Technology in Germany - 20462

Retrievability is a term that is included in most radioactive waste management programs around the world. Although national definitions vary, the overall understanding of retrievability concerns the ability to recover waste packages from the repository mine after their emplacement. Different countries may implement retrievability in very different ways, ranging from a built-in reversibility into the emplacement process to the stipulation that retrievability may in no way impede passive safety in the post-closure phase. Germany takes a middle course such that retrievability in a HLW repository (repository for high level radioactive waste) may have no significant detrimental effect on passive safety. In Germany, the current siting process considers rock salt, clay rock, and crystalline rock as potential host rocks. Therefore, Research and Development (R and D) has been investigating repository concepts and retrievability in all host rocks. After introduction of retrievability in 2010, existing repository concepts were modified to facilitate retrieval. The changes made comprised, for example, equipping boreholes with steel liners, developing new technologies, and modifying existing emplacement devices. Apart from retrieval of HLW, retrieval of other wastes from underground repositories that were designed and operated without retrievability in mind, poses major technical and scientific challenges. Currently, studies are under way to investigate the feasibility and costs of partial retrieval of waste from an underground repository for hazardous and highly toxic waste in France, Stocamine. With regard to retrieval, the rock-mechanical conditions are deteriorating rapidly, so time is of the essence. In the Asse II mine in Germany, about 126,500 waste casks with low and intermediate level waste await retrieval. The repository mine suffers from difficult rock-mechanical conditions and inflow of brine, locally into emplacement areas. The Federal Company for Radioactive Waste Disposal (BGE) is legally required to retrieve all wastes from the Asse. Due to the specific challenges, R and D is needed to develop technical solutions for the safe retrieval from each of the emplacement chambers. R and D on retrievability and retrieval technology does not only address challenges in radioactive or toxic waste retrieval but may also help to germinate innovation to better master complex underground situations in general, e.g. in deep mining, tunneling, or repository construction. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗