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At least 1,081 records · Page 60
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

2020 Results for Avian Monitoring of Inorganic and Organic Element Concentrations in Passerine Eggs and Nestlings Collected from Technical Area 16 Burn Grounds, Technical Area 36 Minie, and Technical Area 39 Point 6 at Los Alamos National Laboratory

In 2020, non-viable avian eggs and two nestling were opportunistically collected at Los Alamos National Laboratory (LANL) near open detonation sites located at Technical Area (TA) 16 burn grounds, TA-36 Minie, and TA-39 Point 6. These samples were evaluated for inorganic elements (mostly metals), dioxins, and furans. A total of six eggs and two deceased western bluebird (Sialia mexicana) nestling samples were collected among the three locations of interest. Concentrations of inorganic elements observed in this study were compared with the regional statistical reference level (RSRL) which is the upper-level bounds of background concentrations (mean + three standard deviations = 99% confidence interval). Several inorganic elements were not detected in avian eggs and all inorganic elements detected were below the RSRL and the lowest observable adverse effect level (LOAEL), when available. One nestling collected from TA-39 contained detectable concentrations of two dioxin congeners. Heptachlorodibenzodioxin-1,2,3,4,6,7,8 and octachlorodibenzodioxin-1,2,3,4,6,7,8,9 concentration exceeded the RSRL, but did not exceed the calculated tetrachlorodibenzodioxin 2,3,7,8 (TCDD) toxic equivalent LOAEL. These data suggest that inorganic and organic element concentrations in eggs and nestlings are not of ecological concern. More data are needed to make a robust assessment and to evaluate trends over time.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

National Community Solar Partnership Technical Assistance: Together New Orleans [Slides]

This product is the outcome of a National Community Solar Partnership (NCSP) Technical Assistance (TA) request. TA is provided to NCSP members at no cost and upon request. Some TA, this project included, is later generalized and published to help educate the broader community, share findings, and provide best practices. Together New Orleans submitted a TA request to the NCSP aiming to obtain a third-party analysis on several rate compensation structures that could make project development more financially advantageous.

14 SOLAR ENERGY↗
DOE OSTI2022

Crack-Free 30% Chromium-Nickel Alloy Welding Products for Nuclear Service

We report prior research in the development of 30% chromium-nickel alloy nuclear welding wires has resulted in the resolution of primary water stress corrosion cracking (PWSCC) and ductility dip cracking (DDC) as well as improvement in solidification cracking (SC) resistance. The resolution of DDC exhibits some Laves phase, which has a negative effect on SC resistance. In this study, the use of an alternate carbide former, tantalum (Ta), in combination with niobium (Nb) was researched. Three heats of recently designed Filler Metal 52MSS-Ta (i.e., HV1648, HV1673A, and VX131WXW) were melted, fabricated, and systematically studied. DDC and SC were evaluated with thermodynamic modeling using the Scheil solidification simulation model, two types of varestraint tests, and strain-to-fracture (STF) testing. The varestraint and STF test results showed an improved SC resistance with reduced Laves phase and concurrent excellent DDC resistance. Optimized compositions with low Laves phase also exhibited high threshold strain values (TSVs) in the STF test. VX131WXW — which contains 2.81 wt-% Ta, 0.6 wt-% Nb, and 6 wt-% iron (Fe) - exhibited a TSV of 24%. Thermo-Calc computed the Laves phase to be 0.24% for VX131WXW compared to 0.06% in HV1673A. This difference in Laves phase resulted in the lower SC resistance of VX131WXW compared to HV1673A when measured with longitudinal varestraint testing. The maximum crack distance for HV1673A was about 0.6 mm while that of heat VX131WXW was about 1.0 mm. The typical diluted weld deposit made with VX131WXW was also resistant to PWSCC due to the chromium content exceeding 24%. These simultaneous results mark progress toward crack-free welds and provide direction for further optimization of Ta-containing filler metals.

30% chromium-nickel alloy↗
DOE OSTI2025

Emergence of Local Magnetic Moment in Ternary TaWSe 2 Single Crystal via Atomic Clustering

Ternary transition metal dichalcogenides (TMDs) provide a versatile platform to explore novel electronic and magnetic ground states via compositional substitution and local structural modulations. Using a combination of scanning tunneling microscopy and spectroscopy (STM/S), magnetic property measurements, and density functional theory (DFT) calculations, the emergence of local magnetic moments driven by the clustering of Ta atoms in ternary TaWSe 2 single crystals is analyzed. STM topography reveals triangular clusters of Ta atoms embedded within W-rich regions of TaWSe 2 . These clusters exhibit a consistent shape and an orderly arrangement throughout the surfaces. DFT calculations show that these Ta clusters induce local strain, giving rise to localized magnetic moments. The magnetic behavior is further corroborated by temperature-dependent magnetization measurements, which exhibit a magnetic anomaly at ∼50 K. In conclusion, this study offers a pathway to engineer magnetism in TMD systems with potential applications in spintronic and quantum materials.

DFT↗
DOE OSTI2020

Materials Data on Ta2N by Materials Project

Ta2N is trigonal omega structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Ta2N sheet oriented in the (0, 0, 1) direction. Ta is bonded in a distorted T-shaped geometry to three equivalent N atoms. All Ta–N bond lengths are 2.18 Å. N is bonded to six equivalent Ta atoms to form edge-sharing NTa6 octahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaRh3 by Materials Project

Rh3Ta is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ta is bonded to twelve equivalent Rh atoms to form TaRh12 cuboctahedra that share corners with twelve equivalent TaRh12 cuboctahedra, edges with twenty-four equivalent RhTa4Rh8 cuboctahedra, faces with six equivalent TaRh12 cuboctahedra, and faces with twelve equivalent RhTa4Rh8 cuboctahedra. All Ta–Rh bond lengths are 2.76 Å. Rh is bonded to four equivalent Ta and eight equivalent Rh atoms to form distorted RhTa4Rh8 cuboctahedra that share corners with twelve equivalent RhTa4Rh8 cuboctahedra, edges with eight equivalent TaRh12 cuboctahedra, edges with sixteen equivalent RhTa4Rh8 cuboctahedra, faces with four equivalent TaRh12 cuboctahedra, and faces with fourteen equivalent RhTa4Rh8 cuboctahedra. All Rh–Rh bond lengths are 2.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaB2 by Materials Project

TaB2 is hexagonal omega structure structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ta is bonded to twelve equivalent B atoms to form a mixture of edge and face-sharing TaB12 cuboctahedra. All Ta–B bond lengths are 2.45 Å. B is bonded in a 9-coordinate geometry to six equivalent Ta and three equivalent B atoms. All B–B bond lengths are 1.79 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaSi2 by Materials Project

TaSi2 is Titanium Disilicide-like structured and crystallizes in the hexagonal P6_422 space group. The structure is three-dimensional. Ta is bonded in a distorted q6 geometry to ten equivalent Si atoms. There are a spread of Ta–Si bond distances ranging from 2.62–2.84 Å. Si is bonded in a 10-coordinate geometry to five equivalent Ta and five equivalent Si atoms. There are a spread of Si–Si bond distances ranging from 2.57–2.84 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaCo3 by Materials Project

Co3Ta is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ta is bonded to twelve equivalent Co atoms to form TaCo12 cuboctahedra that share corners with twelve equivalent TaCo12 cuboctahedra, edges with twenty-four equivalent CoTa4Co8 cuboctahedra, faces with six equivalent TaCo12 cuboctahedra, and faces with twelve equivalent CoTa4Co8 cuboctahedra. All Ta–Co bond lengths are 2.57 Å. Co is bonded to four equivalent Ta and eight equivalent Co atoms to form CoTa4Co8 cuboctahedra that share corners with twelve equivalent CoTa4Co8 cuboctahedra, edges with eight equivalent TaCo12 cuboctahedra, edges with sixteen equivalent CoTa4Co8 cuboctahedra, faces with four equivalent TaCo12 cuboctahedra, and faces with fourteen equivalent CoTa4Co8 cuboctahedra. All Co–Co bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaNi2 by Materials Project

Ni2Ta is Titanium Disilicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ta is bonded in a distorted q6 geometry to ten equivalent Ni atoms. There are eight shorter (2.60 Å) and two longer (2.63 Å) Ta–Ni bond lengths. Ni is bonded in a 10-coordinate geometry to five equivalent Ta and five equivalent Ni atoms. There are four shorter (2.60 Å) and one longer (2.62 Å) Ni–Ni bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaRu by Materials Project

RuTa is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ta is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Ta–Ru bond lengths are 2.75 Å. Ru is bonded in a body-centered cubic geometry to eight equivalent Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2Ta2O6F by Materials Project

Ca2Ta2O6F crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Ca2+ is bonded in a distorted body-centered cubic geometry to six equivalent O2- and two equivalent F1- atoms. All Ca–O bond lengths are 2.52 Å. Both Ca–F bond lengths are 2.25 Å. Ta+4.50+ is bonded to six equivalent O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 51°. All Ta–O bond lengths are 2.04 Å. O2- is bonded to two equivalent Ca2+ and two equivalent Ta+4.50+ atoms to form distorted OCa2Ta2 tetrahedra that share corners with two equivalent FCa4 tetrahedra, corners with twelve equivalent OCa2Ta2 tetrahedra, an edgeedge with one FCa4 tetrahedra, and edges with four equivalent OCa2Ta2 tetrahedra. F1- is bonded to four equivalent Ca2+ atoms to form FCa4 tetrahedra that share corners with four equivalent FCa4 tetrahedra, corners with twelve equivalent OCa2Ta2 tetrahedra, and edges with six equivalent OCa2Ta2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaRu by Materials Project

RuTa is Tetraauricupride structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ta is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Ta–Ru bond lengths are 2.76 Å. Ru is bonded in a body-centered cubic geometry to eight equivalent Ta atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4LiTa3O12 by Materials Project

Ba4LiTa3O12 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TaO6 octahedra, faces with four BaO12 cuboctahedra, and a faceface with one TaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are three shorter (2.00 Å) and three longer (2.40 Å) Li–O bond lengths. There are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, a faceface with one LiO6 octahedra, and faces with seven TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.84–2.95 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.81–3.33 Å. In the third Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with six equivalent BaO12 cuboctahedra, corners with three equivalent LiO6 octahedra, faces with six BaO12 cuboctahedra, and faces with seven TaO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are a spread of Ba–O bond distances ranging from 2.80–2.99 Å. In the fourth Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with three equivalent BaO12 cuboctahedra, faces with three equivalent LiO6 octahedra, and faces with five TaO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.94–3.03 Å. There are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent TaO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one LiO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There are three shorter (1.90 Å) and three longer (2.18 Å) Ta–O bond lengths. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with three equivalent LiO6 octahedra, corners with three equivalent TaO6 octahedra, and faces with five BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are three shorter (1.91 Å) and three longer (2.17 Å) Ta–O bond lengths. In the third Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with seven BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–5°. There are three shorter (2.01 Å) and three longer (2.04 Å) Ta–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to one Li1+, four Ba2+, and one Ta5+ atom. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ta5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to one Li1+, four Ba2+, and one Ta5+ atom. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta2Ni by Materials Project

Ta2Ni is Khatyrkite structured and crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. Ta is bonded in a 4-coordinate geometry to four equivalent Ni atoms. All Ta–Ni bond lengths are 2.64 Å. Ni is bonded in a 10-coordinate geometry to eight equivalent Ta and two equivalent Ni atoms. Both Ni–Ni bond lengths are 2.44 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaTe4 by Materials Project

TaTe4 crystallizes in the tetragonal P4/ncc space group. The structure is one-dimensional and consists of two TaTe4 ribbons oriented in the (0, 0, 1) direction. there are three inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight Te+1.25- atoms. There are four shorter (2.82 Å) and four longer (2.99 Å) Ta–Te bond lengths. In the second Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight Te+1.25- atoms. There are four shorter (2.83 Å) and four longer (2.99 Å) Ta–Te bond lengths. In the third Ta5+ site, Ta5+ is bonded in a 8-coordinate geometry to eight Te+1.25- atoms. There are four shorter (2.92 Å) and four longer (2.93 Å) Ta–Te bond lengths. There are three inequivalent Te+1.25- sites. In the first Te+1.25- site, Te+1.25- is bonded in a 2-coordinate geometry to two Ta5+ atoms. In the second Te+1.25- site, Te+1.25- is bonded in a 3-coordinate geometry to two Ta5+ atoms. In the third Te+1.25- site, Te+1.25- is bonded in a 3-coordinate geometry to two Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaPbS2 by Materials Project

TaPbS2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ta is bonded to six equivalent S atoms to form distorted edge-sharing TaS6 pentagonal pyramids. All Ta–S bond lengths are 2.49 Å. Pb is bonded in a distorted linear geometry to two equivalent S atoms. Both Pb–S bond lengths are 2.96 Å. S is bonded in a distorted rectangular see-saw-like geometry to three equivalent Ta and one Pb atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaMnP by Materials Project

TaMnP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Ta is bonded in a 5-coordinate geometry to five equivalent P atoms. There are two shorter (2.60 Å) and three longer (2.62 Å) Ta–P bond lengths. Mn is bonded to four equivalent P atoms to form a mixture of distorted corner and edge-sharing MnP4 tetrahedra. There are a spread of Mn–P bond distances ranging from 2.27–2.37 Å. P is bonded in a 9-coordinate geometry to five equivalent Ta and four equivalent Mn atoms.

36 MATERIALS SCIENCE↗