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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Effect of Annealing on Structural, Textural, Thermal, Magnetic, and Luminescence Properties of Calcium Fluoride Nanoparticles

Mesoporous nanocrystalline CaF{sub 2} powder was produced by pulsed electron beam evaporation (PEBE) in vacuum. The specific surface area (SSA) of CaF{sub 2} nanopowder (NP) reached 88.7 m{sup 2}/g. The effect of in-air thermal annealing in the temperature range of 200–900°C on the particle size, morphology, textural, thermal, magnetic, and luminescence properties of NPs is studied. A strong deviation from stoichiometry is observed in produced nanoparticles and a significant increase in the SSA after annealing at 200°C. The obtained CaF{sub 2} NP shows ferromagnetic (FM) behavior. The FM response appearance can be explained by the formation of structural and radiation defects. An analysis of pulsed cathodoluminescence (PCL) and magnetization curves of CaF{sub 2} NPs allows conclusions about their interrelation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Constraints on the rheology and texture development of Earth’s inner core from high-pressure diffusion experiments [Slides]

Self-diffusion in the core is likely faster than previous estimates. Self-diffusion anisotropy can account for depth-dependence of seismic attenuation. Inner core has a high viscosity and deformation occurs via pure climb creep which does not result in lattice-preferred orientation. Seismic anisotropy is a result of LPO generated through solidification texturing.

58 GEOSCIENCES↗
DOE OSTI2018

X-Ray Diffraction Texture Analysis of Uranium Alloy Fuel PLN-5527 R0

This test plan describes XRD sample characterization for uranium alloys. This test plan includes preferred sample preparation information, characterization method, instrument parameters, calibration method, analysis software, data-acceptance requirements, documentation/reporting requirements. Texture measurements will be taken based on relative peak shapes (e.g., peak height, area, integrated intensity, etc.), relative to the individual XRD pattern.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Time resolved electrical, optical, and thermal probes of topological spin textures in magnetic nanostructures

This project is a fundamental study of magnetization dynamics in nanoscale spin textures with topological properties. One example is magnetic skyrmions that form in chiral ferromagnetic material systems that lack inversion symmetry. We have concentrated on the scalable chiral magnetic metal B20 FeGe thin film that has an asymmetric exchange interaction due to non-centrosymmetric cubic lattice. While the asymmetric exchange interaction can be found at the interface of a ferromagnet and a heavy metal, manipulation of skyrmions at these interfaces is non-trivial due to pinning and it requires higher critical current. In contrast, B20 materials such as FeGe have superior material quality to offer pinning-free and low-current skyrmion motion.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2024

Understanding the effect of crystal anisotropy on grain growth, texturing and transport via the orthorhombic ?-U system [Slides]

The alpha phase of uranium exhibits the orthorhombic crystal structure, resulting in significant physical property anisotropy. These complex properties make the material challenging to work with in engineering settings but provide a rich arena to investigate the fundamental, multi-scale effects of anisotropy on physical behaviors such as grain growth and microstructure evolution under irradiation. We apply molecular dynamics and phase field modeling to study mass transport and grain growth in alpha-uranium. We characterize the mobilities of crystalline defects and the interfacial energy, and We find that the grain boundary energy is highly variable depending on the interface structure and that the relative rates of defect transport change with temperature. We also find that anisotropic thermal expansion has a significant impact on grain growth kinetics and texture development. Our results are used to explain experimental observations and to provide a basis for further hypotheses into the complex physical behavior of alpha-uranium.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Validating the Funnel, Filter Paper, and Drainage Method for Maximum Water Holding Capacity Over a Wide Range of Soil Textures

The data provided includes the results of maximum water holding capacity using the funnel, filter paper, and drainage (FFPD) method, as well as soil water retention curves generated from the water desorption method (via pressure cells) for a full range of soil textures. It will also include data from sensitivity trials to test readily available materials and varying conditions the FFPD method could be expanded to use for more accessibility to community scientists. The format will be in data tables.

Nelson, Jessica↗
DOE OSTI2018

The Influence of Texture on Co/SBA–15 Catalyst Performance for Fischer–Tropsch Synthesis

The influence of the Co/SBA–15 catalyst texture, such as pore size and pore length on Fischer–Tropsch (FT) Synthesis, was investigated in this paper. The morphology, structure, and microstructures of Co/SBA–15 catalysts were characterized by SEM, Brunauer–Emmett–Teller (BET), TPR, HRTEM, and XRD. The experimental results indicated that the increase of pore size could improve the activity of the Co/SBA–15 catalyst, and the further increase of pore size could not significantly promote the activity. Moreover, it was also found that the pore length of the Co/SBA–15 catalyst played a key role in the catalytic activity. CO 2 and C4+ selectivity were 2.0% and 74% during the simulated syngas (64% H 2 : 32% CO: balanced N 2 ) FT over the Co/SBA–15 catalysts, and CO conversion rate and CH 4 selectivity were 10.8% and 15.7% after 100 h time on stream.

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

Control of Cement Timing, Mineralogy, and Texture on Hydro-chemo-mechanical Coupling from CO2 Injection into Sandstone: A Synthesis

Carbon capture, utilization, and storage (CCUS) has been widely applied to enhance oil recovery (CO2-EOR). A thorough investigation of the impact of injecting CO2 into a heterogeneous reservoir is critical to understanding the overall reservoir robustness and storage performance. We conducted fifteen flow-through tests on Morrow B sandstone that allowed for chemical reactions between a CO2-rich brackish solution and the sandstones, and four creep/flow-through tests that simultaneously allowed for chemical reactions and stress monitoring. From fluid chemistry and X-ray computed tomography, we found that the dissolution of disseminated cements and the precipitation of iron-rich clays did not significantly affect the permeability and geomechanical properties. Minor changes in mechanical properties from Brazilian and creep tests indicated that the matrix structure was well-supported by early diagenetic quartz overgrowth cement and the reservoir’s compaction history at deep burial depths. However, one sample experienced a dissolution of poikilotopic calcite, leading to a permeability increase and significant tensile strength degradation due to pore opening, which overcame the effect of the early diagenetic cements. We concluded that the Morrow B sandstone reservoir is robust for CO2 injection. Most importantly, cement timing, the abundance and texture of reactive minerals, and the reservoir’s burial history are critical in predicting reservoir robustness and storage capacity for CO2 injection.

Wu, Zhidi (ORCID:0000000338869492)↗
DOE OSTI2025

Dynamics and Formation of Antiferromagnetic Textures in MnBi 2 Te 4 Single Crystal

We report coherent X-ray imaging of antiferromagnetic (AFM) domains and domain walls in MnBi 2 Te 4 , an intrinsic AFM topological insulator. This technique enables direct visualization of domain morphology without reconstruction algorithms, allowing us to resolve antiphase domain walls as distinct dark lines arising from the A-type AFM structure. The wall width is determined to be 550(30) nm, in good agreement with earlier magnetic force microscopy results. The temperature dependence of the AFM order parameter extracted from our images closely follows previous neutron scattering data. Remarkably, however, we find a pronounced hysteresis in the evolution of domains and domain walls: upon cooling, dynamic reorganizations occur within a narrow ∼1 K interval below 𝑇 𝑁 , whereas upon warming, the domain configuration remains largely unchanged until AFM order disappears. These findings reveal a complex energy landscape in MnBi 2 Te 4 , governed by the interplay of exchange, anisotropy, and domain-wall energies, and underscore the critical role of AFM domain-wall dynamics in shaping its physical properties. These sharply defined and hysteretically evolving walls may provide a controllable AFM texture in MnBi 2 Te 4 , hinting at potential use in low-power spintronic devices based on domain-wall dynamics.

36 MATERIALS SCIENCE↗