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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

'Direct' Gas-Phase Metallicities, Stellar Properties, and Local Environments of Emission-Line Galaxies at Redshifts Below 0.90

Using deep narrow-band (NB) imaging and optical spectroscopy from the Keck telescope and the Multi Mirror Telescope (MMT), we identify a sample of 20 emission-line galaxies (ELGs) at z = 0.065-0.90 where the weak auroral emission line, [O iii] lambda4363, is detected at >=3sigma. These detections allow us to determine the gas-phase metallicity using the "direct" method. With electron temperature measurements, and dust attenuation corrections from Balmer decrements, we find that 4 of these low-mass galaxies are extremely metal-poor with 12+log(O/H) <= 7.65 or one-tenth solar. Our most metal-deficient galaxy has 12+log(O/H)= 7.24(+0.45 / −0.30) (95% confidence), similar to some of the lowest metallicity galaxies identified in the local universe. We find that our galaxies are all undergoing significant star formation with average specific star formation rate (SFR) of (100 Myra)(exp −1), and that they have high central SFR surface densities (average of 0.5 Solar M / yr/ sq. kpc). In addition, more than two-thirds of our galaxies have between one and four nearby companions within a projected radius of 100 kpc, which we find is an excess among star-forming galaxies at z =0.4 -- 0.85. We also find that the gas-phase metallicities for a given stellar mass and SFR lie systematically lower than the local stellar M-Z-(SFR) relation by approx. = 0.2 dex (2 sigma significance). These results are partly due to selection effects, since galaxies with strong star formation and low metallicity are more likely to yield [O iii] lambda4363 detections. Finally, the observed higher ionization parameter and high electron density suggest that they are lower redshift analogs to typical z approx. > 1 galaxies.

Direct↗
DOE OSTI2019

Electron channeling contrast imaging investigation of stacking fault pyramids in GaP on Si nucleation layers

Thin gallium phosphide layers were deposited on (0 0 1) Silicon surfaces via organometallic vapor phase epitaxy and characterized by electron channeling contrast imaging (ECCI). Stacking fault pyramids at a density of up to 6 x 10 7 cm -2 were identified in the GaP nucleation layer by varying the diffraction conditions. We show that these defects originate at the GaP/Si interface and propagate on all four {1 1 1} planes. We observed that such stacking fault pyramids interact with the gliding of misfit dislocations during lattice-mismatched growth and enhance the threading dislocation density. The initial pulsing of TEGa and TBP during the nucleation of GaP on Silicon has been found to strongly influence the formation of those pyramidal defects. Changing the number of pulse cycles allowed us to lower their density by two orders of magnitude from 6 x 10 7 cm -2 to 4 x 10 5 cm -2 .

36 MATERIALS SCIENCE↗
DOE OSTI2021

Nucleation of High-Quality GaP on Si Through V-Groove Si Substrates

III-V growth on nanopatterned v-groove Si is a promising route to low cost Si-based tandem solar cells. Here, we study a high temperature MOVPE nucleation regime for growing GaP on v-groove Si. It is shown that MOVPE growth conditions can be used to control the facet selectivity of the GaP nucleation onto the v-grooves. The most promising nucleation condition was studied further, and it was demonstrated that it can be coalesced into a smooth thin film with promising material quality.

41 EE - Solar Energy Technologies Office (EE-4S)↗
NASA NTRS1988

Mass flow in the interacting binary TX Ursae Majoris

Twenty-two far-ultraviolet and 23 near-ultraviolet high resolution IUE spectra of the interactive Algol-type binary TX Ursae Majoris (B8 V + F-K III-IV) were analyzed in order to determine the nature of the mass flow occurring in this system. Absorption features due to high-temperature ions of Si IV, C IV, and N V are always present. The resonance lines of Al III, Fe II, Mg II and Si IV show strong phase and secular variations indicative of gas streaming and circumstellar/circumbinary material. Radial velocities as high as 500 to 600 km/sec are present. The gas flow is particularly prominent in 1985 between phases 0.7 and 0.0. The system is more active than U Sagittae and as active as U Cephei.

Mccluskey, G. E., Jr.↗
NASA NTRS1990

Correlation of solar radio pulsations with hard X-ray emission

A systematic study of the correlation of quasi-periodic broad-band decimetric pulsations with hard X-ray (HXR) emission is carried out. It is found that, in 11 out of 56 simultaneously observed events, the decimetric quasi-periodic pulsations in the impulsive phase of flares are correlated. If events with concurring type III bursts are included, 19 cases of radio pulsations are correlated with HXR.

Aschwanden, M. J.↗
DOE OSTI2023

Chemical dismantling of permanent magnet material and battery material

Certain method embodiments are described and useful for recycling permanent magnet materials (e.g. permanent magnet alloys) and battery materials (e.g. battery electrode materials) to extract critical and/or valuable elements including REEs, Co and Ni. Method embodiments involve reacting such material with at least one of an ammonium salt and an iron (III) salt to achieve at least one of a liquid phase chemical reaction and a mechanochemical reaction.

Balema, Viktor↗
DOE OSTI2022

Groundwater-native Fe(II) oxidation prior to aeration with H 2 O 2 to enhance As(III) removal

Groundwater contaminated with arsenic (As) must be treated prior to drinking, as human exposure to As at toxic levels can cause various diseases including cancer. Conventional aeration-filtration applied to anaerobic arsenite (As(III)) contaminated groundwater can remove As(III) by co-oxidizing native iron (Fe(II)) and As(III) with oxygen (O 2 ). However, the As(III) removal efficiency of conventional aeration can be low, in part, because of incomplete As(III) oxidation to readily-sorbed arsenate (As(V)). In this work, we investigated a new approach to enhance As(III) co-removal with native Fe(II) by the anaerobic addition of hydrogen peroxide (H 2 O 2 ) prior to aeration. Experiments were performed to co-oxidize Fe(II) and As(III) with H 2 O 2 (anaerobically), O 2 (aerobically), and by sequentially adding of H 2 O 2 and O 2 . Aqueous As(III) and As(V) measurements after the reaction were coupled with solid-phase speciation by Fe and As K-edge X-ray absorption spectroscopy (XAS). We found that complete anaerobic oxidation of 100 µM Fe(II) with 100 µM H 2 O 2 resulted in co-removal of 95% of 7 µM As(III) compared to 44% with 8.0-9.0 mg/L dissolved O 2 . Furthermore, we found that with 100 µM Fe(II), the initial Fe(II):H 2 O 2 ratio was a critical parameter to remove 7 µM As(III) to below the 10 µg/L (0.13 µM) WHO guideline, where ratios of 1:4 (mol:mol) Fe(II):H 2 O 2 led to As(III) removal matching that of 7 µM As(V). The improved As(III) removal with H 2 O 2 was found to occur partly because of the well-established enhanced efficiency of As(III) oxidation in Fe(II)+H 2 O 2 systems relatively to Fe(II)+O 2 systems. However, the XAS results unambiguously demonstrated that a large factor in the improved As(III) removal was also due to a systematic decrease in crystallinity, and thus increase in specific surface area, of the generated Fe(III) (oxyhydr)oxides from lepidocrocite in the Fe(II)+O 2 system to poorly-ordered Fe(III) precipitates in the Fe(II)+H 2 O 2 system. The combined roles of H 2 O 2 (enhanced As(III) oxidation and structural modification) can be easily overlooked when only aqueous species are measured, but this dual impact must be considered for accurate predictions of As removal in groundwater treatment.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2018

Structural Transformation of Birnessite by Fulvic Acid under Anoxic Conditions

The structure and Mn(III) concentration of birnessite dictate its reactivity and can be changed by birnessite partial reduction, but effects of pH and reductant/birnessite ratios on the changes by reduction remain unclear. We found that the two factors strongly affect the structure of birnessite (δ-MnO 2 ) and its Mn(III) content during its reduction by fulvic acid (FA) at pH 4–8 and FA/solid mass ratios of 0.01–10 under anoxic conditions over 600 h. During the reduction, the structure of δ-MnO 2 is increasingly accumulated with both Mn(III) and Mn(II) but much more with Mn(III) at pH 8, whereas the accumulated Mn is mainly Mn(II) with little Mn(III) at pH 4 and 6. Mn(III) accumulation, either in layers or over vacancies, is stronger at higher FA/solid ratios. At FA/solid ratios ≥1 and pH 6 and 8, additional hausmannite and MnOOH phases form. The altered birnessite favorably adsorbs FA because of the structural accumulation of Mn(II, III). Like during microbially mediated oxidative precipitation of birnessite, the dynamic changes during its reduction are ascribed to the birnessite-Mn(II) redox reactions. Here, our work suggests low reactivity of birnessite coexisting with organic matter and severe decline of its reactivity by partial reduction in alkaline environment.

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

Combustion synthesis of Eu 2 O 3 nanomaterials with tunable phase composition and morphology

Combustion reactions in europium nitrate – acetylacetone – 2-methoxyethanol solutions and gels were investigated to produce europium (III) oxide (Eu 2 O 3 ) nanocrystalline materials and thin films. Thermal analyses of solutions indicated that the 2-methoxyethanol solvent also acts as a fuel in the absence of acetylacetone. Adding acetylacetone increases the overall heat of the reaction. Thermal analysis results revealed that the slow oxidation of unburned hydrocarbon residues follows the primary combustion reaction. Time-temperature profile measurements of the bulk combustion synthesis process in air and nitrogen atmospheres enabled the extraction of the maximum reaction temperature and the heating and cooling rates in the combustion zone. Several direct correlations exist between measured combustion parameters and the phase composition of the products. Combustion in air results in mixed-phase cubic and monoclinic nanocrystalline Eu 2 O 3 . Increasing the acetylacetone concentration in solutions increases the synthesis temperature and decreases the quantity of cubic Eu 2 O 3 . Here, the reaction of solutions in a nitrogen atmosphere or diluted with Eu 2 O 3 provides control of the product phase composition and reduces the quantity of the monoclinic phase. Transmission electron microscopy imaging shows that the Eu 2 O 3 end products are highly porous aggregates of nanocrystalline particles. Electrospraying of reactive solutions onto different substrates followed by short annealing makes the preparation of Eu 2 O 3 materials with diverse morphologies possible.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

The Mobility of Mo during Microbially Mediated Ferrihydrite Phase Transformation

Molybdenum (Mo) is an essential nutrient for almost all organisms. However, at high concentrations, it can be toxic to animals and plants. This study investigated the interactions of Mo(VI) with iron oxyhydroxides during ferrihydrite bioreduction in the presence of the Fe(III)- reducing Geobacter sulfurreducens. Here, in this study, we showed that Mo concentration controlled ferrihydrite phase transformation, leading to Mo release. With the biotic reduction of ferrihydrite and Fe(II) production, Mo(VI) reduction and Mo(IV)O 2 formation were observed for the first time, which further immobilised Mo after surface adsorption of Mo(VI). At low Mo levels (Mo/Fe molar ratios of 1-2 %), sufficient Fe(II) adsorption onto ferrihydrite resulted in its transformation into magnetite nanoparticles (>80%, ~25 nm) which catalysed the reduction of Mo(VI) to form Mo(IV)O 2 and immobilised Mo. Contrastingly, at high Mo concentrations (Mo/Fe molar ratios of 5-10%), Mo(VI)O 4 2- adsorption onto ferrihydrite limited Fe(II) adsorption, subsequently less magnetite (<8-12%) formed while more goethite (~30- 50%, width & length > 15 & 100 nm, respectively) and siderite (~20-30%, width & length > 100 & 200 nm, respectively) with larger particle sizes formed instead, causing Mo(VI) release due to lower Mo adsorption. This study provides a comprehensive understanding of the interaction mechanisms among Geobacter sulfurreducens, Mo(VI), and iron oxyhydroxides, enabling predictions and controls of long-term Mo mobility and Fe mineral transformation under a variety of biogeochemical scenarios.

Geobacter sulfurreducens↗
DOE OSTI2016

ECO2N V2.0: A TOUGH2 fluid property module for modeling CO 2 -H 2 O-NACL systems to elevated temperatures of up to 300°C

Here, we have improved ECO2N, the TOUGH2 fluid property module of the CO 2 -H 2 O-NaCl system. The major enhancements include: (i) the upper temperature limit is increased from 110 to about 300°C; (ii) the thermophysical properties of the CO 2 -rich phase are more accurately calculated as a non-ideal mixture of CO 2 and H 2 O; (iii) the approach to calculate the specific enthalpy of dissolved CO 2 has been improved to make the code more robust in modeling phase transitions under non-isothermal conditions; and (iv) more sophisticated models for effective heat conductivity of formations saturated with supercritical CO 2 have been provided. The new module includes a comprehensive description of the thermodynamic and thermophysical properties of H 2 O–NaCl–CO 2 mixtures, that reproduces fluid properties largely within experimental error for the temperature, pressure and salinity conditions 10°C < T < 300°C, P < 600 bar, and salinity up to halite saturation. This includes density, viscosity, and specific enthalpy of fluid phases as functions of temperature, pressure, and composition, as well as partitioning of mass components H 2 O, NaCl and CO 2 among the different phases. ECO2N with the TOUGH2 reservoir simulator can be applied to a wide range of problems in geologic sequestration of CO 2 in saline aquifers, and in enhanced geothermal reservoirs. Finally, ECO2N can describe both sub- and supercritical states of CO 2 , but applications that involve subcritical conditions are limited to systems in which there is no change of phase between liquid and gaseous CO 2 , and in which no mixtures of liquid and gaseous CO 2 occur.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRSDate not supplied

EVA Operations for Artemis III External Teams

The purpose of this presentation is to give external Artemis III Teams (payloads, industry) some basic information on EVA Operations and hardware impacts in the design, the planning, and the real-time phases of the mission.

EVA↗
DOE OSTI2014

'Direct' gas-phase metallicities, stellar properties, and local environments of emission-line galaxies at redshifts below 0.90

Using deep narrow-band (NB) imaging and optical spectroscopy from the Keck telescope and MMT, we identify a sample of 20 emission-line galaxies at z = 0.065-0.90 where the weak auroral emission line, [O III] λ4363, is detected at ≥3σ. These detections allow us to determine the gas-phase metallicity using the 'direct' method. With electron temperature measurements, and dust attenuation corrections from Balmer decrements, we find that four of these low-mass galaxies are extremely metal-poor with 12 + log (O/H) ≤ 7.65 or one-tenth solar. Our most metal-deficient galaxy has 12 + log (O/H) = 7.24{sub −0.30}{sup +0.45} (95% confidence), similar to some of the lowest metallicity galaxies identified in the local universe. We find that our galaxies are all undergoing significant star formation with average specific star formation rate (SFR) of (100 Myr){sup –1}, and that they have high central SFR surface densities (average of 0.5 M {sub ☉} yr{sup –1} kpc{sup –2}). In addition, more than two-thirds of our galaxies have between one and four nearby companions within a projected radius of 100 kpc, which we find is an excess among star-forming galaxies at z = 0.4-0.85. We also find that the gas-phase metallicities for a given stellar mass and SFR lie systematically lower than the local M {sub *}-Z-(SFR) relation by ≈0.2 dex (2σ significance). These results are partly due to selection effects, since galaxies with strong star formation and low metallicity are more likely to yield [O III] λ4363 detections. Finally, the observed higher ionization parameter and high electron density suggest that they are lower redshift analogs to typical z ≳ 1 galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2019

Pressure-induced semiconductor-to-metal phase transition of a charge-ordered indium halide perovskite

Phase transitions in halide perovskites triggered by external stimuli generate significantly different material properties, providing a great opportunity for broad applications. Here, we demonstrate an In-based, charge-ordered (In + /In 3+ ) inorganic halide perovskite with the composition of Cs 2 In(I)In(III)Cl 6 in which a pressure-driven semiconductor-to-metal phase transition exists. The single crystals, synthesized via a solid-state reaction method, crystallize in a distorted perovskite structure with space group I 4/ m with a = 17.2604(12) Å, c = 11.0113(16) Å if both the strong reflections and superstructures are considered. The supercell was further confirmed by rotation electron diffraction measurement. The pressure-induced semiconductor-to-metal phase transition was demonstrated by high-pressure Raman and absorbance spectroscopies and was consistent with theoretical modeling. This type of charge-ordered inorganic halide perovskite with a pressure-induced semiconductor-to-metal phase transition may inspire a range of potential applications.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Identification of NpO 2+x in the binary Np-O system

In contrast to UO 2 and PuO 2 , there is no consensus on the existence of mixed valence NpO 2+x , resulting in a gap between NpO 2 and Np 2 O 5 (the highest binary oxide of Np) in the Np-O phase diagram. We now show NpO 2+x via Np L III Extended X-ray Absorption Fine Structure (EXAFS) spectra of three samples of NpO 2 that, analogous to U and Pu, exhibit multisite Np-O distributions with varying numbers of oxygen atoms at 1.87–1.91 Å. Furthermore this is supported by the diffraction pattern of the sample with the largest amount of this oxo-type species that can be refined with both the simple fluorite structure and a trigonal one related to α-U 4 O 9 . The implied Np(V)-bridging oxo moieties as well as possible indications of OH - found by detailed EXAFS analysis suggest that NpO 2+x more closely resembles PuO 2+x than UO 2+x . An additional common characteristic suggested by the EXAFS and X-Ray Diffraction (XRD) is the phase separation into NpO 2 and what would be previously unreported Np 4 O 9(-δ) , indicative of O clustering.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Estimation of Sorption Behavior of Europium(III) Using Biotite Flakes - 13272

The interaction of biotite and Eu(III) (europium (III)) was examined by using secondary ion-microprobe mass spectrometer (SIMS), fluorescence emission spectrum and decay behavior of fluorescence emission spectrum in addition to the time-changes of Eu(III) and potassium ions concentrations in a solution, using the flake form samples. The results of SIMS showed that the intensity of Eu was gradually decreasing with depth, while the intensity of Eu in the case shaken for 30 days exceeded that in the case for 1 day. Furthermore, the spatial distribution of Eu(III) and potassium ions in the flake of biotite suggested that Eu ions diffuse mainly from the edges of biotite flake, while Eu ions can slightly diffuse through some small cracks existing on the flake surface far from the edges. Besides, the elution amount of potassium from the biotite flakes into a solution was proportional to the sorption amount of Eu(III). The changes nearly revealed ion exchange between these ions, while muscovite flake sample did not show such ion exchange reaction. In addition, from the time-change of Eu(III) concentration, an apparent diffusion coefficient was estimated to be 8.0x10{sup -12} m{sup 2}/s, by using two-dimensional diffusion model coupled with a film between the solid phase and the liquid phase. Furthermore, the fluorescent intensity decreased with the shaking (contacting) time. This means that Eu(III) gradually diffuses into the inside of biotite edges of the biotite flakes, after the sorption of Eu(III) in the edges. This tendency was observed also in the powder samples. The observed fluorescence decay (at 592 nm in wave length) showed almost similar curve in any samples, indicating a certain sorption form of Eu(III) onto the edges of the biotite flakes. These results mentioned above suggest that the diffusion processes through internal layer in biotite mainly control the sorption behavior of multivalent ions. Such diffusion processes affect the retardation-effects on fracture surfaces in the rock matrix, depending on the fluid flow velocity of groundwater. That is, a more reliable model considering the mass transfer in the internal layer of biotite may be required to estimate the sorption behavior of RNs with biotite which controls the whole sorption behavior of granite. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRS2024

EVA Operations for the Artemis III Science Team

The purpose of this presentation is to give the newly selected Artemis III Science Team some basic information on EVA Operations and potential interactions with the science team in both the planning and real-time phases of the mission.

EVA↗
NASA NTRSDate not supplied

NASA's Initial Artemis Human Landing System

In April 2020, NASA announced the selection of three companies to begin the initial phase of development of human landing systems to take the first woman and the first person of color to the lunar surface through NASA’s Artemis lunar exploration program. The selected companies were a Blue Origin-led team with Lockheed Martin, Northrup Grumman, and Draper; Dynetics (a Leidos company); and SpaceX. Contracts were awarded shortly after, kicking off a ten-month base period during which NASA worked closely with each company to finalize functional and performance requirements, confirm lander development standards, and establish baseline designs, schedules, and management plans for contract execution and human spaceflight certification. At the end of the base period, in the Spring of 2021, NASA awarded a single follow-on Option A contract to SpaceX to continue their work on Human Landing System (HLS) Starship development. Currently NASA and SpaceX are working collaboratively on Option A which will ultimately culminate in one uncrewed and one crewed mission to the lunar surface under Artemis III. This paper will provide a look at the Option A phase of development for the Human Landing System Program, including publicly available information on SpaceX’s HLS Starship design as well as near-term and future milestones for HLS and the Artemis program.

Lisa Watson-Morgan↗