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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on KSc2Co by Materials Project

KSc2Co crystallizes in the cubic F-43m space group. The structure is three-dimensional. K is bonded in a distorted body-centered cubic geometry to four equivalent Sc and four equivalent Co atoms. All K–Sc bond lengths are 3.09 Å. All K–Co bond lengths are 3.09 Å. There are two inequivalent Sc sites. In the first Sc site, Sc is bonded to four equivalent K atoms to form distorted corner-sharing ScK4 tetrahedra. In the second Sc site, Sc is bonded to four equivalent Co atoms to form distorted corner-sharing ScCo4 tetrahedra. All Sc–Co bond lengths are 3.09 Å. Co is bonded in a distorted body-centered cubic geometry to four equivalent K and four equivalent Sc atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc3Co2Si3 by Materials Project

Sc3Co2Si3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Sc+2.67+ sites. In the first Sc+2.67+ site, Sc+2.67+ is bonded to five Si4- atoms to form ScSi5 trigonal bipyramids that share corners with four equivalent CoSi4 tetrahedra, corners with six equivalent ScSi5 trigonal bipyramids, and edges with four equivalent CoSi4 tetrahedra. There are a spread of Sc–Si bond distances ranging from 2.70–3.05 Å. In the second Sc+2.67+ site, Sc+2.67+ is bonded in a 6-coordinate geometry to six Si4- atoms. There are a spread of Sc–Si bond distances ranging from 2.77–2.90 Å. Co2+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with three equivalent CoSi4 tetrahedra, corners with two equivalent ScSi5 trigonal bipyramids, edges with two equivalent CoSi4 tetrahedra, and edges with two equivalent ScSi5 trigonal bipyramids. There are a spread of Co–Si bond distances ranging from 2.28–2.45 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to seven Sc+2.67+ and two equivalent Co2+ atoms. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to five Sc+2.67+, three equivalent Co2+, and one Si4- atom. The Si–Si bond length is 2.49 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La3ScAl8 by Materials Project

La3ScAl8 is Hexagonal Laves-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are three inequivalent La sites. In the first La site, La is bonded in a 12-coordinate geometry to four La and twelve Al atoms. There are three shorter (3.47 Å) and one longer (3.53 Å) La–La bond lengths. There are a spread of La–Al bond distances ranging from 3.32–3.38 Å. In the second La site, La is bonded in a 12-coordinate geometry to three equivalent La, one Sc, and twelve Al atoms. The La–Sc bond length is 3.48 Å. There are a spread of La–Al bond distances ranging from 3.32–3.42 Å. In the third La site, La is bonded in a 12-coordinate geometry to one La, three equivalent Sc, and twelve Al atoms. All La–Sc bond lengths are 3.46 Å. There are a spread of La–Al bond distances ranging from 3.28–3.32 Å. Sc is bonded in a 12-coordinate geometry to four La and twelve Al atoms. There are a spread of Sc–Al bond distances ranging from 3.28–3.31 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded to four La, two equivalent Sc, and six Al atoms to form a mixture of edge, face, and corner-sharing AlLa4Sc2Al6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.80–2.88 Å. In the second Al site, Al is bonded to five La, one Sc, and six Al atoms to form a mixture of edge, face, and corner-sharing AlLa5ScAl6 cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.81–2.90 Å. In the third Al site, Al is bonded to three equivalent La, three equivalent Sc, and six Al atoms to form AlLa3Sc3Al6 cuboctahedra that share corners with eighteen AlLa4Sc2Al6 cuboctahedra, edges with six equivalent AlLa3Sc3Al6 cuboctahedra, and faces with eighteen AlLa4Sc2Al6 cuboctahedra. In the fourth Al site, Al is bonded to six La and six Al atoms to form AlLa6Al6 cuboctahedra that share corners with eighteen AlLa4Sc2Al6 cuboctahedra, edges with six equivalent AlLa6Al6 cuboctahedra, and faces with eighteen AlLa4Sc2Al6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc3(Ni10B3)2 by Materials Project

Sc3(Ni10B3)2 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Sc sites. In the first Sc site, Sc is bonded to twelve equivalent Ni atoms to form distorted ScNi12 cuboctahedra that share edges with twenty-four equivalent NiScNi6B3 tetrahedra and faces with eight equivalent ScNi16 tetrahedra. All Sc–Ni bond lengths are 2.58 Å. In the second Sc site, Sc is bonded to sixteen Ni atoms to form distorted ScNi16 tetrahedra that share edges with six equivalent ScNi16 tetrahedra, edges with twelve equivalent NiScNi6B3 tetrahedra, faces with four equivalent ScNi12 cuboctahedra, and faces with four equivalent NiScNi6B3 tetrahedra. There are four shorter (2.50 Å) and twelve longer (2.91 Å) Sc–Ni bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded to one Sc, six equivalent Ni, and three equivalent B atoms to form distorted NiScNi6B3 tetrahedra that share corners with three equivalent NiScNi6B3 tetrahedra, edges with three equivalent ScNi12 cuboctahedra, edges with three equivalent ScNi16 tetrahedra, edges with three equivalent NiScNi6B3 tetrahedra, a faceface with one ScNi16 tetrahedra, and faces with six equivalent NiScNi6B3 tetrahedra. All Ni–Ni bond lengths are 2.65 Å. All Ni–B bond lengths are 2.13 Å. In the second Ni site, Ni is bonded in a 2-coordinate geometry to three Sc, nine Ni, and two equivalent B atoms. There are one shorter (2.36 Å) and four longer (2.58 Å) Ni–Ni bond lengths. Both Ni–B bond lengths are 2.09 Å. B is bonded in a 8-coordinate geometry to eight Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hf2Sc3Si4 by Materials Project

Sc3Hf2Si4 crystallizes in the tetragonal P4_12_12 space group. The structure is three-dimensional. there are two inequivalent Sc+2.67+ sites. In the first Sc+2.67+ site, Sc+2.67+ is bonded to six Si4- atoms to form ScSi6 octahedra that share corners with four equivalent ScSi6 octahedra, corners with eight equivalent ScSi7 pentagonal bipyramids, corners with six equivalent HfSi6 pentagonal pyramids, faces with four equivalent ScSi7 pentagonal bipyramids, and faces with four equivalent HfSi6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 54°. There are a spread of Sc–Si bond distances ranging from 2.73–2.94 Å. In the second Sc+2.67+ site, Sc+2.67+ is bonded to seven Si4- atoms to form distorted ScSi7 pentagonal bipyramids that share corners with four equivalent ScSi6 octahedra, corners with six equivalent ScSi7 pentagonal bipyramids, corners with five equivalent HfSi6 pentagonal pyramids, edges with three equivalent ScSi7 pentagonal bipyramids, edges with two equivalent HfSi6 pentagonal pyramids, faces with two equivalent ScSi6 octahedra, faces with two equivalent ScSi7 pentagonal bipyramids, and faces with four equivalent HfSi6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 44–52°. There are a spread of Sc–Si bond distances ranging from 2.76–3.08 Å. Hf4+ is bonded to six Si4- atoms to form distorted HfSi6 pentagonal pyramids that share corners with three equivalent ScSi6 octahedra, corners with five equivalent ScSi7 pentagonal bipyramids, corners with four equivalent HfSi6 pentagonal pyramids, edges with two equivalent ScSi7 pentagonal bipyramids, edges with four equivalent HfSi6 pentagonal pyramids, faces with two equivalent ScSi6 octahedra, and faces with four equivalent ScSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–45°. There are a spread of Hf–Si bond distances ranging from 2.63–2.81 Å. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to five Sc+2.67+, three equivalent Hf4+, and one Si4- atom. The Si–Si bond length is 2.51 Å. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to five Sc+2.67+, three equivalent Hf4+, and one Si4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc2Mn12P7 by Materials Project

Sc2Mn12P7 crystallizes in the hexagonal P-6 space group. The structure is three-dimensional. there are two inequivalent Sc sites. In the first Sc site, Sc is bonded in a 6-coordinate geometry to six equivalent P atoms. All Sc–P bond lengths are 2.74 Å. In the second Sc site, Sc is bonded in a 12-coordinate geometry to six equivalent P atoms. All Sc–P bond lengths are 2.75 Å. There are four inequivalent Mn sites. In the first Mn site, Mn is bonded to four P atoms to form a mixture of edge and corner-sharing MnP4 tetrahedra. There are a spread of Mn–P bond distances ranging from 2.27–2.33 Å. In the second Mn site, Mn is bonded to four P atoms to form a mixture of distorted edge and corner-sharing MnP4 tetrahedra. There are a spread of Mn–P bond distances ranging from 2.24–2.35 Å. In the third Mn site, Mn is bonded to four P atoms to form a mixture of edge and corner-sharing MnP4 tetrahedra. There are a spread of Mn–P bond distances ranging from 2.28–2.33 Å. In the fourth Mn site, Mn is bonded in a 5-coordinate geometry to five P atoms. There are a spread of Mn–P bond distances ranging from 2.44–2.55 Å. There are three inequivalent P sites. In the first P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Mn atoms. In the second P site, P is bonded in a 9-coordinate geometry to two equivalent Sc and seven Mn atoms. In the third P site, P is bonded in a 9-coordinate geometry to nine Mn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg5Sc by Materials Project

Mg5Sc is Magnesium-derived structured and crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded to ten Mg and two equivalent Sc atoms to form MgMg10Sc2 cuboctahedra that share corners with eighteen MgMg10Sc2 cuboctahedra, edges with four equivalent ScMg12 cuboctahedra, edges with fourteen MgMg10Sc2 cuboctahedra, faces with four equivalent ScMg12 cuboctahedra, and faces with sixteen MgMg10Sc2 cuboctahedra. There are a spread of Mg–Mg bond distances ranging from 3.16–3.30 Å. Both Mg–Sc bond lengths are 3.20 Å. In the second Mg site, Mg is bonded to nine Mg and three equivalent Sc atoms to form MgMg9Sc3 cuboctahedra that share corners with nine equivalent MgMg9Sc3 cuboctahedra, corners with nine equivalent ScMg12 cuboctahedra, edges with eighteen MgMg10Sc2 cuboctahedra, faces with three equivalent ScMg12 cuboctahedra, and faces with seventeen MgMg10Sc2 cuboctahedra. There are four shorter (3.16 Å) and three longer (3.22 Å) Mg–Mg bond lengths. All Mg–Sc bond lengths are 3.22 Å. In the third Mg site, Mg is bonded to ten Mg and two equivalent Sc atoms to form MgMg10Sc2 cuboctahedra that share corners with eighteen MgMg10Sc2 cuboctahedra, edges with four equivalent ScMg12 cuboctahedra, edges with fourteen MgMg9Sc3 cuboctahedra, faces with four equivalent ScMg12 cuboctahedra, and faces with sixteen MgMg10Sc2 cuboctahedra. There are two shorter (3.17 Å) and one longer (3.30 Å) Mg–Mg bond lengths. Both Mg–Sc bond lengths are 3.20 Å. In the fourth Mg site, Mg is bonded to ten Mg and two equivalent Sc atoms to form MgMg10Sc2 cuboctahedra that share corners with eighteen MgMg10Sc2 cuboctahedra, edges with four equivalent ScMg12 cuboctahedra, edges with fourteen MgMg9Sc3 cuboctahedra, faces with four equivalent ScMg12 cuboctahedra, and faces with sixteen MgMg10Sc2 cuboctahedra. Both Mg–Sc bond lengths are 3.20 Å. Sc is bonded to twelve Mg atoms to form ScMg12 cuboctahedra that share corners with eighteen equivalent MgMg9Sc3 cuboctahedra, edges with six equivalent ScMg12 cuboctahedra, edges with twelve MgMg10Sc2 cuboctahedra, faces with two equivalent ScMg12 cuboctahedra, and faces with eighteen MgMg10Sc2 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Exploring the potential and impact of single-crystal active materials on dry-processed electrodes for high-performance lithium-ion batteries

Roll-to-roll powder-to-film dry processing (DP) and single-crystal (SC) active materials (AMs) with many advantages are two hot topics of lithium-ion batteries (LIBs). However, DP of SC AMs for LIBs is rarely reported. Consequently, the impact of SC AMs on dry-processed LIBs is not well understood. Herein, for the first time, via a set of experimental and theoretical studies of the conventional polycrystalline-AM- and SC-AM-based DPed electrodes (DPEs), this work not only reports a high-performance dry SC-AM cathode for LIB manufacturing, but also establishes some fundamental understanding of SC-based dry-processed electrodes, including their morphology, structure, mechanical strength, electronic conductivity and LIB electrochemical behavior. Further, the results suggest that DP of SC AMs is promising, which can dramatically improve the electrochemical kinetics at electrode level and particle level. Specifically, for the rate capability and long-term cyclability in full cells, SC DPEs exhibit a discharge specific capacity of 152.1 mAh g -1 at 1C and a capacity retention rate of 79.9 % at C/3 over 500 cycles, which are superior to those of PC DPEs (135.6 mAh g -1 and 68.3 %) at the same conditions and are further confirmed by the simulation data from the theoretical modelling study. Therefore, this comprehensive work marks a significant milestone for DP strategy and SC AMs, enlightening future research and development of LIB manufacturing.

25 ENERGY STORAGE↗
DOE OSTI2024

Stabilization of N6 and N8 anionic units and 2D polynitrogen layers in high-pressure scandium polynitrides

Abstract Nitrogen catenation under high pressure leads to the formation of polynitrogen compounds with potentially unique properties. The exploration of the entire spectrum of poly- and oligo-nitrogen moieties is still in its earliest stages. Here, we report on four novel scandium nitrides, Sc 2 N 6 , Sc 2 N 8 , ScN 5, and Sc 4 N 3 , synthesized by direct reaction between yttrium and nitrogen at 78-125 GPa and 2500 K in laser-heated diamond anvil cells. High-pressure synchrotron single-crystal X-ray diffraction reveals that in the crystal structures of the nitrogen-rich Sc 2 N 6 , Sc 2 N 8, and ScN 5 phases nitrogen is catenated forming previously unknown N 6 6 − and N 8 6 − units and$${\!\,}_{\infty }{\!\,}^{2}({{{{{\rm{N}}}}}}_{5}^{3-})$$ ∞ 2 ( N 5 3 − ) anionic corrugated 2D-polynitrogen layers consisting of fused N 12 rings. Density functional theory calculations, confirming the dynamical stability of the synthesized compounds, show that Sc 2 N 6 and Sc 2 N 8 possess an anion-driven metallicity, while ScN 5 is an indirect semiconductor. Sc 2 N 6 , Sc 2 N 8 , and ScN 5 solids are promising high-energy-density materials with calculated volumetric energy density, detonation velocity, and detonation pressure higher than those of TNT.

Science & Technology - Other Topics↗
DOE OSTI2025

Impact of charge-density-wave pattern on the superconducting gap in Vanadium-based kagome superconductors

Kagome metals AV 3 Sb 5 (A = K, Rb, Cs) provide a compelling platform to explore the interplay between superconductivity (SC) and charge-density-wave (CDW) orders. While distinct CDW orders have been identified in K/RbV 3 Sb 5 versus CsV 3 Sb 5 , their influence on the SC order parameter remains unresolved. Here, we investigate low-energy quasiparticle excitations in AV 3 Sb 5 , uncovering a striking difference in SC gap anisotropy: K/RbV 3 Sb 5 exhibit fully gapped, nearly isotropic s-wave states, in contrast to the strongly anisotropic SC gap in CsV 3 Sb 5 . Impurity scattering introduced via electron irradiation in K/RbV 3 Sb 5 has a minimal impact on low-energy excitations, and it induces an increase in the SC transition temperature T c , consistent with more isotropic s-wave SC competing with CDW order. Our theoretical analysis attributes the observed SC gap anisotropy differences to distinct CDW modulation patterns: the star-of-David structure unique to CsV 3 Sb 5 preserves van Hove singularities near the Fermi level, promoting anisotropic s-wave SC with enhanced T c via bond-order fluctuations. These findings establish a systematic framework for understanding the interplay between SC and CDW orders in AV 3 Sb 5 , driven by electron correlations.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

McMillan electron lens in a system with space charge

Space charge (SC) forces of a circulating beam in a ring have both linear (defocusing) and nonlinear components, due to a nonuniform beam distribution. The linear component of SC forces produces a betatron tune shift, which is the largest for a zero-amplitude particle, while the nonlinear component produces an amplitude-dependent betatron tune spread. These SC effects are responsible for several undesirable phenomena in accelerators: emittance growth, particle losses, beam halo, etc. In this paper, we investigate the possibility to mitigate the distributed SC forces by a thin McMillan lens, providing an axially-symmetric kick, which is qualitatively opposite to the accumulated effect of beam's own SC. Experimentally, the proposed concept can be tested in Fermilab's IOTA ring. A thin McMillan lens can be implemented by a short (70) insertion of an electron beam with a specifically chosen density distribution in transverse directions. In this article, to test if McMillan lenses can reduce the tune spread induced by SC, we make several simulations with a 6-D particle tracking code, Synergia. We choose such beam and lattice parameters that the SC tune spread is roughly 0.5 and the emittance growth due to the half-integer resonance is clearly observed without the SC compensation. Then, we focus on reducing the emittance growth by adjusting the bare betatron tunes using the ring quadrupoles, and reducing the tune spread by the McMillan lenses. The results of reducing a large tune spread (≈ 0.5), reported here, are not perfect, but substantial. There is still room for further investigation. The simulations performed so far in this work indicate that McMillan lenses can cope with an SC tune spread of ≈ 0.1 per lens.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Analysis of diagonal G and subspace W approximations within fully self-consistent GW calculations for bulk semiconducting systems

Fully self-consistent GW (sc-GW) methods are now available to evaluate quasiparticle and spectral properties of various molecular and bulk systems. However, such techniques based on the full matrix of G and W are computationally demanding. Additionally, the routinely used single-shot GW approximation (G 0 W 0 ) has an undesirable dependency on the choice of initial exchange-correlation functional. In the literature, many so-called self-consistent GW methods are based on diagonal approximation of G and low-ranking approximation of W. It is thus worth checking how good such approximations are in comparison with the full matrix method. In this work, we consider AlAs, AlP, GaP, and ZnS as the prototype systems to perform sc-GW calculations by expressing the full G matrix using a plane-wave basis set. We compared our sc-GW results with the diagonal G and subspace W approximated sc-GW results (sc-GW-diagG and sc-GW-subW methods). In the sc-GW-diagG method, interacting G is expanded in the eigenvectors of noninteracting G such that only diagonal elements are retained, whereas the number of eigenmodes is truncated in sc-GW-subW calculations. A systematic analysis of the results obtained from the above techniques is presented. The differences in the quasiparticle band gap between the approximated and the full matrix sc-GW approaches are mostly less than 1.7%, which validates such widely adopted approximations, and also shows how such low-ranking approximation can be used to include higher-order terms such as the vertex correction.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Comparison and Discussion on Shortcircuit Protections for Silicon-Carbide MOSFET Modules: Desaturation Versus Rogowski Switch-Current Sensor

Survivability of silicon-carbide (SiC) mosfet modules during short circuit (SC) is essential for modern power electronics systems due to large economic implications. SiC mosfet modules exhibit narrow SC withstand times and generally much lower SC robustness than silicon (Si) insulated-gate bipolar transistors (IGBTs). This puts a critical concern on their utilization, further stressing the importance of reliable protection. This article presents a comprehensive analysis and discussion on the SiC mosfet module SC protection and performance comparison between conventional desaturation detection, previously used for Si IGBT protection, and Rogowski switch-current sensor (RSCS) detection. In addition, this article presents the experimental design for soft turn-off as a reaction to the SC detection to avoid excessive overshoots during the abrupt turn-off of the SC current. To perform different types of SC with various fault inductances on different temperatures, and for the sake of fair comparison under the same conditions, a gate-driver unit for 1.2 kV SiC mosfet half-bridge modules is developed containing both detection methods. The results demonstrate that both methods are successful in protecting the module in all SC types, with superiority of the RSCS detection and concerns for desaturation detection in high-inductance and high dc-bus voltage SC events.

42 ENGINEERING↗
DOE OSTI2025

Dynamic molecular architecture of the synaptonemal complex

During meiosis, pairing between homologous chromosomes is stabilized by the assembly of the synaptonemal complex (SC). The SC ensures the formation of crossovers between homologous chromosomes and regulates their distribution. However, how the SC regulates crossover formation remains elusive. We isolated an unusual mutation in Caenorhabditis elegans that disrupts crossover interference but not SC assembly. This mutation alters the unique C terminal domain of an essential SC protein, SYP-4, a likely ortholog of the vertebrate SC protein SIX6OS1. We use three-dimensional stochastic optical reconstruction microscopy (3D-STORM) to interrogate the molecular architecture of the SC from wild-type and mutant C. elegans animals. Using a probabilistic mapping approach to analyze super-resolution image data, we detect changes in the organization of the synaptonemal complex in wild-type animals that coincide with crossover designation. We also found that our syp-4 mutant perturbs SC architecture. Our findings add to growing evidence that the SC is an active material whose molecular organization contributes to chromosome-wide crossover regulation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Production of Radioisotopes of Scandium for Imaging and Therapy (Final Report)

The theranostic approach is a powerful technique that enables scientists and physicians to diagnose and treat diseases using the same targeting moiety labeled with radionuclides for imaging and therapy. A challenge behind synthesizing and evaluating these theranostic radiopharmaceuticals lies in the production of suitable radionuclides. This study aimed to investigate the production of high radionuclidic purity 43 Sc from enriched [ 46 Ti]TiO 2 for Positron Emission Tomography (PET) and 47 Sc from enriched [ 50 Ti]TiO 2 for targeted radiotherapy, as well as establish a target recycling technique for continued production of these radionuclides. Methods: Targets were prepared with 100 mg of either enriched [ 46 Ti]TiO 2 or [ 50 Ti]TiO 2 , pressed into pellets, and placed into Ta target holders with a 0.127 mm natTi cover foil. The 46 Ti targets were bombarded with 18 MeV protons at 20 µA for 1.5 h, while 50Ti targets were bombarded with 24 MeV protons at 20 µA for 4 or 8 h. The radioscandium nuclides were purified using branched N, N, N’, N’ -tetra-2-ethylhexyldiglycolamide (DGA) resin. The titanium targets were recycled by precipitating the dissolved Ti collected from the column effluent and wash streams, pH adjustment, vacuum filtration, and then drying the solid at 250 °C prior to reforming the target for the subsequent bombardment. The apparent molar activity of the isolated radioscandiums was analyzed by titration with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). The relative imaging performance of 18 F, 43 Sc, and 68 Ga were analyzed with PET images acquired with 30-min static scans. Results: The average radioscandium recovery for 43Sc was 91.7 ± 7.4 %, with a radionuclidic purity of 98.8 %. The average recovery of 47Sc was 89.9 ± 3.9 %, with a radionuclidic purity of 90.8%. The average recovery of enriched TiO2 was 96 ± 4.0 %. The highest apparent molar activity for [43Sc]Sc-DOTA was 23.2 GBq/µmol and 3.39 GBq/µmol for [ 47 Sc]Sc-DOTA. The order of PET resolution from highest to lowest was 18 F > 43 Sc > 68 Ga. Conclusions: This work demonstrates the feasibility of using enriched recycled [ 46 Ti]TiO 2 and [ 50 Ti]TiO 2 targets for the production of the 43 Sc and 47 Sc theranostic isotope pair in high purity.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2020

Biaxial steel plated concrete constitutive models for composite structures: Implementation and validation

The Steel-plated Concrete (SC) technique is an alternative construction technique with faster onsite construction speed, reduced construction time, and increased structural performance. Aiming to predict the force transfer mechanism of SC elements, an innovative constitutive model package is proposed by implementing experimental-based biaxial steel plate concrete models into the nonlinear finite element (FE) model “Membrane Model of SC (MM-CS).” First, the formulation and implementation of the MM-SC is illustrated in detail, including the equilibrium and compatibility equations and the implementation of constitutive models. Next, various experimental data of SC members are selected and simulated using the proposed MM-SC model. In this research, two types of structures, SC panels and framed SC shear walls, and three types of loading conditions, including uniaxial compression, pure shear, and combined axial-flexural-shear tests, are analyzed respectively. Good agreements were obtained between the reported results and the FE simulation results in terms of yield capacity and ultimate capacity, proving the reliability of the implemented analytical constitutive material models and the biaxial membrane model formulations.

42 ENGINEERING↗
DOE OSTI2020

Materials Data on Sc2Al3Ru by Materials Project

Sc2RuAl3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Sc is bonded in a 12-coordinate geometry to four equivalent Sc, three equivalent Ru, and nine equivalent Al atoms. There are three shorter (3.20 Å) and one longer (3.33 Å) Sc–Sc bond lengths. All Sc–Ru bond lengths are 3.10 Å. There are three shorter (3.03 Å) and six longer (3.13 Å) Sc–Al bond lengths. Ru is bonded to six equivalent Sc and six equivalent Al atoms to form RuSc6Al6 cuboctahedra that share corners with twelve equivalent AlSc6Al4Ru2 cuboctahedra, edges with six equivalent RuSc6Al6 cuboctahedra, faces with two equivalent RuSc6Al6 cuboctahedra, and faces with eighteen equivalent AlSc6Al4Ru2 cuboctahedra. All Ru–Al bond lengths are 2.62 Å. Al is bonded to six equivalent Sc, two equivalent Ru, and four equivalent Al atoms to form distorted AlSc6Al4Ru2 cuboctahedra that share corners with four equivalent RuSc6Al6 cuboctahedra, corners with fourteen equivalent AlSc6Al4Ru2 cuboctahedra, edges with six equivalent AlSc6Al4Ru2 cuboctahedra, faces with six equivalent RuSc6Al6 cuboctahedra, and faces with twelve equivalent AlSc6Al4Ru2 cuboctahedra. There are two shorter (2.63 Å) and two longer (2.68 Å) Al–Al bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sc2Pt by Materials Project

Sc2Pt is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Sc sites. In the first Sc site, Sc is bonded in a 3-coordinate geometry to three equivalent Pt atoms. There are one shorter (2.70 Å) and two longer (2.89 Å) Sc–Pt bond lengths. In the second Sc site, Sc is bonded to four equivalent Pt atoms to form a mixture of edge and corner-sharing ScPt4 tetrahedra. There are a spread of Sc–Pt bond distances ranging from 2.70–2.78 Å. Pt is bonded in a 7-coordinate geometry to seven Sc atoms.

36 MATERIALS SCIENCE↗