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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Dispersion and Aging of Volcanic Aerosols after the La Soufriere Eruption in April 2021

Volcanic aerosols change the atmospheric composition and thereby affect weather and climate. Aerosol dynamic processes such as nucleation, condensation, and coagulation modify the shape, size, and mass of aerosol particles, which influence their atmospheric lifetime and radiative properties. Nevertheless, most models omit these processes for ash particles. In this work, we explore the ash aerosol aging and sulfate production during the first 4 days following the 2021 La Soufrière (St. Vincent) eruption with the ICON-ART model (ICOsahedral Nonhydrostatic model with Aerosol and Reactive Trace gases). Online coupling of ICON-ART with a one-dimensional volcanic plume model calculates volcanic emission, which makes it possible to resolve the different eruption phases of the noncontinuous La Soufrière eruption. We compared our simulated aerosol distribution and composition with observations from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument, the Multiangle Imaging SpectroRadiometer (MISR) Research Aerosol (RA) Algorithm, and the Barbados Cloud Observatory (BCO). We show that online coupling is essential to adequately model the emissions and plume development close to the volcano. The modeled aerosol aging is in very good agreement with observations from MISR near the emission source and with CALIOP at larger distances. Furthermore, particle aging occurs faster in the troposphere than in the stratosphere due to the availability of water vapor and OH, but a layer of coated ash appears at the plume top due to faster oxidation of SO2 and lofting by aerosol-radiation interaction. This paper gives the first direct comparison of aerosol aging in volcanic eruption plumes between simulations and observations

volcanic aerosols↗
DOE OSTI2020

Start-up of Silo 130 Waste Retrieval at La Hague: first Step Towards Reducing Legacy Inventory - 20020

On June 25, 2019, the first grapple of waste and debris was lifted from Silo 130, one of the most challenging legacy waste storage silos at La Hague. This was the achievement of more than ten years of studies and efforts focused on solving some very unique technical and safety challenges, and on designing an innovative, efficient solution. The waste is from de-cladding materials from past Gas-Cooled Reactor fuel reprocessing operations. It is an unsorted mixture of magnesium cladding pieces, graphite debris, and various other metallic waste types. These materials can be chemically reactive and therefore need specific dispositions for handling and storing. The building is more than 40 years old and does not meet modern standards. French safety authorities have required the silo to be emptied. After about three years of operation, the bulk of this waste will be removed and placed in safe storage, pending the selection of a final conditioning solution. Removal of bottom debris will then be possible. When finished, this operation will bring a conclusion to a significant legacy-related hazard on the site. The silo will then be available for final cleaning and de-activation. This paper will describe the technical, safety, and economical challenges, and the various decisions and optimizations that led to the definition of the process and technology to be implemented. Several innovative features were developed and implemented, in all sections of the project: project organization, progressive approach for the waste disposition strategy, light building design, customized and robust retrieval technology, processing technologies involving the most modern robotic and sorting techniques, storage method... Several of these first-of-a-kind innovative features have been developed and qualified specifically for this application, using the detailed qualification procedure specified for all La Hague projects. The facility was built in less than five years, overcoming various difficulties along the line. Commissioning is now finished with the combined efforts of the project, engineering, start-up, and operating teams assisted by dedicated suppliers. The facility is now ramping-up. The paper will also report on the commissioning and start-up of the facility and describe the first operational results. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Panel Session 12: Effective Aspects of the 2016 Consent Order between DOE-EM-LA Field Office - NM Environment Department and Identifying Comparable Approaches

This panel focused on the extremely effective 2016 Compliance Order on Consent executed between the US Department of Energy (DOE) Office of Environmental Management - Los Alamos Field Office (EM-LA) and the New Mexico Environment Department (NMED) and highlights practices and concepts toward developing an environmental compliance agreement that is mutually productive to both the NMED and the DOE. To further demonstrate successful practices, the panel also highlighted another very effective compliance agreement with comparable approaches - the 1993 Savannah River Site (SRS) Federal Facility Agreement (FFA) executed between DOE, the South Carolina Department of Health and Environmental Control (SCDHEC), and the Environmental Protection Agency (EPA). EM-LA, NMED, SRS, and SCDHEC representatives provided attendees an opportunity to understand and compare extremely effective approaches to regulatory compliance across the complex.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2025

Temperature Dependent Spin Dynamics in La 0.67 Sr 0.33 MnO 3 /Pt Bilayers

Complex ferromagnetic oxides such as La 0.67 Sr 0.33 MnO 3 (LSMO) offer pathways for creating energy‐efficient spintronic devices with new functionalities. LSMO exhibits high‐temperature ferromagnetism, half metallicity, sharp resonance linewidth, low damping, and a large anisotropic magnetoresistance response. Combined with Pt, a proven material with high spin‐charge conversion efficiency, LSMO can be used to create robust nano‐oscillators for neuromorphic computing. Ferromagnetic resonance (FMR) and device‐level spin‐pumping FMR measurements are performed to investigate the magnetization dynamics and spin transport in NdGaO 3 (110)/LSMO(15 nm)/Pt(0 and 5 nm) thin films ranging from 300 K to 90 K and compare the device performance with Py(7 nm)/Pt(5 nm) sample. The spin current pumped into Pt is quantified to determine the temperature‐dependent influence of interfacial interactions. The generated spin current in the micro‐device is maximum at 170 K for the optimally grown LSMO/Pt films. Additionally, this bilayer system exhibits low magnetic Gilbert damping (0.002), small linewidth (12 Oe), and a large spin Hall angle (≈3.2%) at 170 K. Ex situ deposited LSMO/Pt bilayers demonstrate excellent dynamic response, exhibiting fourfold enhancement in signal output, eightfold reduction in damping, and a threefold reduction in linewidth as compared to the Pt/Py system. Such robust device‐level performance can pave way for energy‐efficient spintronic‐based devices.

complex perovskite thin films↗
DOE OSTI2026

Electrostatic gate-controlled quantum interference in a high-mobility two-dimensional electron gas at the (La 0.3 ⁢Sr 0.7 )(Al 0.65 ⁢Ta 0.35 )O 3 /SrTiO 3 interface

Here, we report quantum oscillations in magnetoresistance that are periodic in magnetic field (𝐵), observed at the interface between (La 0.3 ⁢Sr 0.7 )(Al 0.65 ⁢Ta 0.35 )O 3 and SrTiO 3 . Unlike Shubnikov–de Haas oscillations, which appear at magnetic fields > 7 T and diminish quickly as the temperature rises, these 𝐵-periodic oscillations emerge at low fields and persist up to 10 K. Their amplitude decays exponentially with both temperature and field, specifying dephasing of quantum interference. Increasing the carrier density through electrostatic gating results in a systematic reduction in both the amplitude and frequency of the oscillations, with complete suppression beyond a certain gate voltage. We attribute these oscillations to the Altshuler-Aronov-Spivak effect, likely arising from naturally formed closed-loop paths due to the interconnected quasi-one-dimensional conduction channels along SrTiO 3 domain walls. The relatively long phase coherence length (≃ 1.8 µ⁢m at 0.1 K), estimated from the oscillation amplitude, highlights the potential of complex oxide interfaces as a promising platform for exploring quantum interference effects and advancing device concepts in quantum technologies, such as mesoscopic interferometers and quantum sensors.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(BC)2 by Materials Project

LaB2C2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. La2+ is bonded in a body-centered cubic geometry to eight equivalent C4- atoms. All La–C bond lengths are 2.84 Å. B3+ is bonded in a distorted trigonal planar geometry to three equivalent C4- atoms. There is one shorter (1.54 Å) and two longer (1.62 Å) B–C bond length. C4- is bonded in a 3-coordinate geometry to four equivalent La2+ and three equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(SiAu)2 by Materials Project

LaAu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La2+ is bonded in a 8-coordinate geometry to eight equivalent Au1- atoms. All La–Au bond lengths are 3.39 Å. Au1- is bonded to four equivalent La2+ and four equivalent Si atoms to form a mixture of distorted edge, face, and corner-sharing AuLa4Si4 tetrahedra. All Au–Si bond lengths are 2.60 Å. Si is bonded in a 5-coordinate geometry to four equivalent Au1- and one Si atom. The Si–Si bond length is 2.37 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(P3Ru)4 by Materials Project

LaRu4P12 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. La3+ is bonded to twelve equivalent P1- atoms to form LaP12 cuboctahedra that share faces with eight equivalent RuP6 octahedra. All La–P bond lengths are 3.13 Å. Ru+2.25+ is bonded to six equivalent P1- atoms to form RuP6 octahedra that share corners with six equivalent RuP6 octahedra and faces with two equivalent LaP12 cuboctahedra. The corner-sharing octahedral tilt angles are 62°. All Ru–P bond lengths are 2.37 Å. P1- is bonded in a 5-coordinate geometry to one La3+, two equivalent Ru+2.25+, and two equivalent P1- atoms. There are one shorter (2.30 Å) and one longer (2.34 Å) P–P bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(SiAg)2 by Materials Project

LaAg2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded to eight equivalent Si4- atoms to form LaSi8 hexagonal bipyramids that share corners with sixteen equivalent AgSi4 tetrahedra, edges with four equivalent LaSi8 hexagonal bipyramids, edges with eight equivalent AgSi4 tetrahedra, and faces with four equivalent LaSi8 hexagonal bipyramids. All La–Si bond lengths are 3.27 Å. Ag+2.50+ is bonded to four equivalent Si4- atoms to form AgSi4 tetrahedra that share corners with eight equivalent LaSi8 hexagonal bipyramids, corners with four equivalent AgSi4 tetrahedra, edges with four equivalent LaSi8 hexagonal bipyramids, and edges with four equivalent AgSi4 tetrahedra. All Ag–Si bond lengths are 2.63 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent La3+, four equivalent Ag+2.50+, and one Si4- atom. The Si–Si bond length is 2.35 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(NiAs)2 by Materials Project

LaNi2As2 crystallizes in the tetragonal P4/nmm space group. The structure is three-dimensional. La3+ is bonded in a 8-coordinate geometry to eight As3- atoms. There are four shorter (3.22 Å) and four longer (3.23 Å) La–As bond lengths. There are two inequivalent Ni+1.50+ sites. In the first Ni+1.50+ site, Ni+1.50+ is bonded in a 5-coordinate geometry to five As3- atoms. There are four shorter (2.41 Å) and one longer (2.43 Å) Ni–As bond lengths. In the second Ni+1.50+ site, Ni+1.50+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing NiAs4 tetrahedra. All Ni–As bond lengths are 2.46 Å. There are two inequivalent As3- sites. In the first As3- site, As3- is bonded in a 9-coordinate geometry to four equivalent La3+ and five Ni+1.50+ atoms. In the second As3- site, As3- is bonded in a 4-coordinate geometry to four equivalent La3+ and four equivalent Ni+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(FeAs3)4 by Materials Project

LaFe4As12 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. La3+ is bonded to twelve equivalent As+1.25- atoms to form LaAs12 cuboctahedra that share faces with eight equivalent FeAs6 octahedra. All La–As bond lengths are 3.16 Å. Fe3+ is bonded to six equivalent As+1.25- atoms to form FeAs6 octahedra that share corners with six equivalent FeAs6 octahedra and faces with two equivalent LaAs12 cuboctahedra. The corner-sharing octahedral tilt angles are 56°. All Fe–As bond lengths are 2.37 Å. As+1.25- is bonded in a 2-coordinate geometry to one La3+, two equivalent Fe3+, and two equivalent As+1.25- atoms. There are one shorter (2.61 Å) and one longer (2.62 Å) As–As bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(CoB)2 by Materials Project

LaCo2B2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded in a body-centered cubic geometry to eight equivalent B3- atoms. All La–B bond lengths are 3.07 Å. Co+1.50+ is bonded to four equivalent B3- atoms to form a mixture of distorted corner and edge-sharing CoB4 tetrahedra. All Co–B bond lengths are 1.99 Å. B3- is bonded in a 4-coordinate geometry to four equivalent La3+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(FeSb3)4 by Materials Project

LaFe4Sb12 crystallizes in the cubic Im-3 space group. The structure is three-dimensional. La3+ is bonded to twelve equivalent Sb+1.25- atoms to form LaSb12 cuboctahedra that share faces with eight equivalent FeSb6 octahedra. All La–Sb bond lengths are 3.42 Å. Fe3+ is bonded to six equivalent Sb+1.25- atoms to form FeSb6 octahedra that share corners with six equivalent FeSb6 octahedra and faces with two equivalent LaSb12 cuboctahedra. The corner-sharing octahedral tilt angles are 52°. All Fe–Sb bond lengths are 2.55 Å. Sb+1.25- is bonded in a 2-coordinate geometry to one La3+, two equivalent Fe3+, and two equivalent Sb+1.25- atoms. There are one shorter (3.00 Å) and one longer (3.03 Å) Sb–Sb bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(CuSi)2 by Materials Project

LaCu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All La–Si bond lengths are 3.17 Å. Cu+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CuSi4 tetrahedra. All Cu–Si bond lengths are 2.44 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent La3+, four equivalent Cu+2.50+, and one Si4- atom. The Si–Si bond length is 2.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(FeSi)2 by Materials Project

LaFe2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All La–Si bond lengths are 3.21 Å. Fe+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of distorted edge and corner-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.28 Å. Si4- is bonded in a 4-coordinate geometry to four equivalent La3+ and four equivalent Fe+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(SiPt)2 by Materials Project

LaPt2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La2+ is bonded to eight equivalent Si4- atoms to form LaSi8 hexagonal bipyramids that share corners with sixteen equivalent PtSi4 tetrahedra, edges with four equivalent LaSi8 hexagonal bipyramids, edges with eight equivalent PtSi4 tetrahedra, and faces with four equivalent LaSi8 hexagonal bipyramids. All La–Si bond lengths are 3.29 Å. Pt3+ is bonded to four equivalent Si4- atoms to form PtSi4 tetrahedra that share corners with eight equivalent LaSi8 hexagonal bipyramids, corners with four equivalent PtSi4 tetrahedra, edges with four equivalent LaSi8 hexagonal bipyramids, and edges with four equivalent PtSi4 tetrahedra. All Pt–Si bond lengths are 2.50 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent La2+, four equivalent Pt3+, and one Si4- atom. The Si–Si bond length is 2.45 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La(CoP)2 by Materials Project

LaCo2P2 is alpha bismuth trifluoride-derived structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. La3+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. There are a spread of La–P bond distances ranging from 3.10–3.14 Å. Co+1.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing CoP4 tetrahedra. There are two shorter (2.21 Å) and two longer (2.22 Å) Co–P bond lengths. P3- is bonded in a 8-coordinate geometry to four equivalent La3+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗