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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Na2HoTa5O15 by Materials Project

Na2HoTa5O15 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.70–3.13 Å. Ho3+ is bonded to twelve O2- atoms to form HoO12 cuboctahedra that share faces with two equivalent HoO12 cuboctahedra and faces with eight equivalent TaO6 octahedra. There are four shorter (2.56 Å) and eight longer (2.66 Å) Ho–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–33°. There is two shorter (1.96 Å) and four longer (2.00 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form TaO6 octahedra that share corners with six TaO6 octahedra and faces with two equivalent HoO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 12–42°. There are a spread of Ta–O bond distances ranging from 1.92–2.05 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Na1+ and two Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ho3+, and two equivalent Ta5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+ and two equivalent Ta5+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Na1+ and two equivalent Ta5+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ho3+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ho2Ni12P7 by Materials Project

Ho2Ni12P7 crystallizes in the hexagonal P-6 space group. The structure is three-dimensional. there are two inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six equivalent P3- atoms to form distorted HoP6 pentagonal pyramids that share corners with six equivalent NiP5 square pyramids, corners with twelve NiP4 tetrahedra, edges with twelve NiP4 tetrahedra, and faces with two equivalent HoP6 pentagonal pyramids. All Ho–P bond lengths are 2.87 Å. In the second Ho3+ site, Ho3+ is bonded to six equivalent P3- atoms to form distorted HoP6 pentagonal pyramids that share corners with six equivalent NiP5 square pyramids, corners with twelve NiP4 tetrahedra, edges with three equivalent NiP5 square pyramids, edges with nine NiP4 tetrahedra, and faces with two equivalent HoP6 pentagonal pyramids. All Ho–P bond lengths are 2.85 Å. There are four inequivalent Ni+1.25+ sites. In the first Ni+1.25+ site, Ni+1.25+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent HoP6 pentagonal pyramids, corners with four equivalent NiP5 square pyramids, corners with ten NiP4 tetrahedra, edges with three HoP6 pentagonal pyramids, an edgeedge with one NiP5 square pyramid, and edges with four NiP4 tetrahedra. There are a spread of Ni–P bond distances ranging from 2.25–2.34 Å. In the second Ni+1.25+ site, Ni+1.25+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with four HoP6 pentagonal pyramids, corners with two equivalent NiP5 square pyramids, corners with ten NiP4 tetrahedra, an edgeedge with one HoP6 pentagonal pyramid, edges with four equivalent NiP5 square pyramids, and edges with three NiP4 tetrahedra. There are a spread of Ni–P bond distances ranging from 2.15–2.31 Å. In the third Ni+1.25+ site, Ni+1.25+ is bonded to five P3- atoms to form distorted NiP5 square pyramids that share corners with four HoP6 pentagonal pyramids, corners with four equivalent NiP5 square pyramids, corners with eight NiP4 tetrahedra, an edgeedge with one HoP6 pentagonal pyramid, edges with four equivalent NiP5 square pyramids, and edges with seven NiP4 tetrahedra. There are a spread of Ni–P bond distances ranging from 2.29–2.56 Å. In the fourth Ni+1.25+ site, Ni+1.25+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent HoP6 pentagonal pyramids, corners with two equivalent NiP5 square pyramids, corners with twelve NiP4 tetrahedra, edges with three HoP6 pentagonal pyramids, edges with two equivalent NiP5 square pyramids, and edges with three NiP4 tetrahedra. There are a spread of Ni–P bond distances ranging from 2.23–2.33 Å. There are three inequivalent P3- sites. In the first P3- site, P3- is bonded in a 3-coordinate geometry to nine Ni+1.25+ atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Ho3+ and seven Ni+1.25+ atoms. In the third P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Ho3+ and seven Ni+1.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Chilled water temperature set-point reset based on outdoor air temperature and its cooling energy performance in an office building

Here, in this study, the cooling energy performance of two strategies for controlling ChWT (chilled water temperature) are compared: the conventional control strategy of constantly fixing ChWT and the OAT (outdoor air temperature) compensation control strategy that adjusts ChWT according to the changes in OAT. OAT compensation control strategy was modeled and realized based on Appendix G of ASHRAE Standard 90.1. It was confirmed that applying OAT compensation control strategy can significantly reduce chiller energy consumption, which accounts for the largest portion of total cooling energy consumption. It was found that the difference in total cooling energy consumption between applying the conventional control of constantly fixing ChWT to 6 °C and applying the OAT compensation control was approximately 8 % and 3 % during spring (March to May) and summer (June to August), respectively. Additionally, during the fall (September–November) period, about 7 % of total cooling energy consumption could be saved.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2020

Mechanoadaptive strain and functional osseointegration of dental implants in rats

Spatiotemporal implant-bone biomechanics and mechanoadaptive strains in peri-implant tissue are poorly understood. Physical and chemical characteristics of an implant-bone complex (IBC) were correlated in three-dimensional space (along the length and around a dental implant) to gather insights into time related integration of the implant with the cortical portion of a jaw bone in a rat. Rats (N = 9) were divided into three experimental groups with three rats per time point; 3-, 11-, and 24-day. All rats were fed crumbled hard pellets mixed with water (soft-food diet) for the first 3 days followed by a hard-food diet with intact hard-food pellets (groups of 11- and 24-day only). Biomechanics of the IBCs harvested from rats at each time point was evaluated by performing mechanical testing in situ in tandem with X-ray imaging. The effect of physical association (contact area) of a loaded implant with adapting peri-implant tissue, and resulting strain within was mapped by using digital volume correlation (DVC) technique. The IBC stiffness at respective time points was correlated with mechanical strain in peri-implant tissue. Results illustrated that IBC stiffness at 11-day was lower than that observed at 3-day. However, at 24-day, IBC stiffness recovered to that which was observed at 3-day. Furthermore, correlative microscopy and spectroscopy illustrated that the lower IBC stiffness was constituted by softer and less mineralized peri-implant tissue that contained varying expressions of osteoconductive elements. Lower IBC stiffness observed at 11-day was constituted by less mineralized peri-implant tissue with osteoconductive elements that included phosphorus (P) which was co-localized with higher expression of zinc (Zn), and lower expression of calcium (Ca). Higher IBC stiffness at 24-day was constituted by mineralized peri-implant tissue with higher expressions of osteoconductive elements including Ca and P, and lower expressions of Zn. These spatiotemporal correlative maps of peri-implant tissue architecture, heterogeneous distribution of mineral density, and elemental colocalization underscore mechanoadaptive physicochemical properties of peri-implant tissue that facilitate functional osseointegration of an implant. These results provided insights into 1) plausible "prescription" of mechanical loads as an osteoinductive "therapeutic dose" to encourage osteoconductive elements in the peri-implant tissue that would facilitate functional osseointegration of the implant; 2) a "critical temporal window" between 3 and 11 days, and perhaps it is this acute phase during which key candidate regenerative molecules can be harnessed to accelerate osseointegration of an implant under load.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Photoemission and dynamical mean field theory study of electronic correlations in a t 2 g 5 metal SrRhO 3 thin film

Perovskite rhodates are characterized by intermediate strengths of both electronic correlation as well as spin-orbit coupling (SOC) and usually behave as moderately correlated metals. A recent publication on epitaxial SrRhO 3 thin films reported a bad-metallic behavior and suggested the occurrence of antiferromagnetism below 100 K. In this work, we have further studied this SrRhO 3 thin film by hard x-ray photoemission spectroscopy and found a very small density of states (DOS) at the Fermi level $(E_F)$, which is consistent with the previously reported bad-metallic behavior. However, the absence of DOS persists up to room temperature, which contradicts the explanation of antiferromagnetic transition at ~100 K. We also employed electronic structure calculations within the framework of density functional theory and dynamical mean-field theory. In contrast to the photoemission results, our calculations indicate metallic behaviors of both bulk SrRhO 3 and the SrRhO 3 thin film, and a stronger correlation effect was observed in the thin film than that in the bulk. The calculated uniform magnetic susceptibility is substantially larger in the thin film than that in the bulk. We also investigated the role of SOC and found only a moderate modulation of the band structure. Hence SOC is not expected to significantly affect the electronic correlation in SrRhO 3 . Extrinsic effects of finite-thickness effects beyond our calculations and localization effects may play important roles to induce the negligible spectral weight at $(E_F)$.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na3HoTi2Nb2O12 by Materials Project

Na3HoTi2Nb2O12 is Orthorhombic Perovskite-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 3-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.34–2.91 Å. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.80 Å. In the third Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.37–2.69 Å. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.29–2.54 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six NbO6 octahedra. The corner-sharing octahedra tilt angles range from 25–33°. There are a spread of Ti–O bond distances ranging from 1.87–2.17 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six NbO6 octahedra. The corner-sharing octahedra tilt angles range from 25–31°. There are a spread of Ti–O bond distances ranging from 1.87–2.15 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six TiO6 octahedra. The corner-sharing octahedra tilt angles range from 25–31°. There are a spread of Nb–O bond distances ranging from 1.92–2.16 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with six TiO6 octahedra. The corner-sharing octahedra tilt angles range from 25–33°. There are a spread of Nb–O bond distances ranging from 1.90–2.15 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Nb5+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ti4+, and one Nb5+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the fourth O2- site, O2- is bonded in a distorted tetrahedral geometry to one Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the fifth O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the sixth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Ti4+, and one Nb5+ atom. In the seventh O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the ninth O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the eleventh O2- site, O2- is bonded in a 5-coordinate geometry to two Na1+, one Ho3+, one Ti4+, and one Nb5+ atom. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to three Na1+, one Ti4+, and one Nb5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Initial Characterization of Active Transitioning Centaur, P/2019 LD{sub 2} (ATLAS), Using Hubble, Spitzer, ZTF, Keck, Apache Point Observatory, and GROWTH Visible and Infrared Imaging and Spectroscopy

We present visible and mid-infrared imagery and photometry of temporary Jovian co-orbital comet P/2019 LD{sub 2} taken with Hubble Space Telescope/Wide Field Camera 3 (HST/WFC3), Spitzer Space Telescope/Infrared Array Camera (Spitzer/IRAC), and the GROWTH telescope network, visible spectroscopy from Keck/Low-Resolution Imaging Spectrometer (LRIS), and archival Zwicky Transient Facility observations taken between 2019 April and 2020 August. Our observations indicate that the nucleus of LD{sub 2} has a radius between 0.2 and 1.8 km assuming a 0.08 albedo and a coma dominated by ∼100 μm-scale dust ejected at ∼1 m s{sup −1} speeds with a ∼1′ jet pointing in the southwest direction. LD{sub 2} experienced a total dust mass loss of ∼10{sup 8} kg at a loss rate of ∼6 kg s{sup −1} with Afρ/cross section varying between ∼85 cm/125 km{sup 2} and ∼200 cm/310 km{sup 2} from 2019 April 9 to 2019 November 8. If the increase in Afρ/cross section remained constant, it implies LD{sub 2}'s activity began ∼2018 November when within 4.8 au of the Sun, implying the onset of H{sub 2}O sublimation. We measure CO/CO{sub 2} gas production of ≲10{sup 27} mol s{sup −1}/≲10{sup 26} mol s{sup −1} from our 4.5 μm Spitzer observations; g–r = 0.59 ± 0.03, r–i = 0.18 ± 0.05, and i–z = 0.01 ± 0.07 from GROWTH observations; and H{sub 2}O gas production of ≲80 kg s{sup −1} scaling from our estimated C {sub 2} production of Q{sub C{sub 2}}≲7.5×10{sup 24} mol s{sup −1} from Keck/LRIS spectroscopy. We determine that the long-term orbit of LD{sub 2} is similar to Jupiter-family comets having close encounters with Jupiter within ∼0.5 Hill radius in the last ∼3 y and within 0.8 Hill radius in ∼9 y. Additionally, 78.8% of our orbital clones are ejected from the solar system within 1 × 10{sup 6} yr, having a dynamical half-life of 3.4 × 10{sup 5} yr.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

SNS Warm Linac Circulator Breakdown Considerations for the PPU Project

Multipacting in accelerating structures is a complex phenomenon about which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures which have a higher thermal capacity, and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Benchmarking of the peak electric fields in these structures, benefits of material processing and possible techniques for reducing or eliminating multipacting activities are discussed.

Toby, George↗
DOE OSTI2020

Materials Data on Ho5(ReO6)2 by Materials Project

Ho5(ReO6)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Ho–O bond distances ranging from 2.27–2.49 Å. In the second Ho3+ site, Ho3+ is bonded to six O2- atoms to form HoO6 octahedra that share corners with four equivalent ReO6 octahedra, corners with four equivalent HoO7 pentagonal bipyramids, and edges with two equivalent HoO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are two shorter (2.20 Å) and four longer (2.31 Å) Ho–O bond lengths. In the third Ho3+ site, Ho3+ is bonded to seven O2- atoms to form distorted HoO7 pentagonal bipyramids that share corners with two equivalent HoO6 octahedra, an edgeedge with one HoO6 octahedra, edges with two equivalent ReO6 octahedra, and edges with two equivalent HoO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 56°. There are a spread of Ho–O bond distances ranging from 2.27–2.42 Å. Re+4.50+ is bonded to six O2- atoms to form ReO6 octahedra that share corners with two equivalent HoO6 octahedra, edges with two equivalent ReO6 octahedra, and edges with two equivalent HoO7 pentagonal bipyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of Re–O bond distances ranging from 1.97–2.10 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to two Ho3+ and two equivalent Re+4.50+ atoms to form distorted OHo2Re2 trigonal pyramids that share corners with eight OHo3Re tetrahedra, edges with four equivalent OHo3Re tetrahedra, and an edgeedge with one OHo2Re2 trigonal pyramid. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+ and two equivalent Re+4.50+ atoms. In the third O2- site, O2- is bonded to three Ho3+ and one Re+4.50+ atom to form distorted OHo3Re tetrahedra that share corners with ten OHo3Re tetrahedra, a cornercorner with one OHo2Re2 trigonal pyramid, edges with three OHo3Re tetrahedra, and edges with two equivalent OHo2Re2 trigonal pyramids. In the fourth O2- site, O2- is bonded to four Ho3+ atoms to form OHo4 tetrahedra that share corners with ten OHo3Re tetrahedra, corners with three equivalent OHo2Re2 trigonal pyramids, and edges with four OHo3Re tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca2HoF7 by Materials Project

Ca2HoF7 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are six inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of Ca–F bond distances ranging from 2.03–2.82 Å. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to seven F1- atoms. There are a spread of Ca–F bond distances ranging from 2.28–2.51 Å. In the third Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ca–F bond distances ranging from 2.27–2.41 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Ca–F bond distances ranging from 2.27–2.42 Å. In the fifth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Ca–F bond distances ranging from 2.36–2.59 Å. In the sixth Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight F1- atoms. There are a spread of Ca–F bond distances ranging from 2.28–2.60 Å. There are three inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Ho–F bond distances ranging from 2.15–2.80 Å. In the second Ho3+ site, Ho3+ is bonded in a 10-coordinate geometry to ten F1- atoms. There are a spread of Ho–F bond distances ranging from 2.15–2.78 Å. In the third Ho3+ site, Ho3+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Ho–F bond distances ranging from 2.15–2.71 Å. There are twenty-one inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to four Ca2+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three Ca2+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three equivalent Ca2+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to three Ca2+ atoms. In the fifth F1- site, F1- is bonded to three equivalent Ca2+ and one Ho3+ atom to form distorted corner-sharing FCa3Ho tetrahedra. In the sixth F1- site, F1- is bonded in a distorted trigonal planar geometry to three equivalent Ca2+ atoms. In the seventh F1- site, F1- is bonded in a distorted trigonal planar geometry to three Ca2+ atoms. In the eighth F1- site, F1- is bonded in a trigonal planar geometry to three Ho3+ atoms. In the ninth F1- site, F1- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ca2+ and two equivalent Ho3+ atoms. In the tenth F1- site, F1- is bonded in a 4-coordinate geometry to one Ca2+ and three equivalent Ho3+ atoms. In the eleventh F1- site, F1- is bonded in a distorted trigonal planar geometry to three Ho3+ atoms. In the twelfth F1- site, F1- is bonded in a trigonal non-coplanar geometry to three Ho3+ atoms. In the thirteenth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Ca2+ and two equivalent Ho3+ atoms. In the fourteenth F1- site, F1- is bonded in a distorted single-bond geometry to four Ho3+ atoms. In the fifteenth F1- site, F1- is bonded in a trigonal non-coplanar geometry to three Ho3+ atoms. In the sixteenth F1- site, F1- is bonded in a distorted single-bond geometry to four Ho3+ atoms. In the seventeenth F1- site, F1- is bonded in a 1-coordinate geometry to three Ca2+ atoms. In the eighteenth F1- site, F1- is bonded in a trigonal non-coplanar geometry to two equivalent Ca2+ and one Ho3+ atom. In the nineteenth F1- site, F1- is bonded in a 3-coordinate geometry to three equivalent Ca2+ atoms. In the twentieth F1- site, F1- is bonded to four Ca2+ atoms to form distorted corner-sharing FCa4 trigonal pyramids. In the twenty-first F1- site, F1- is bonded in a rectangular see-saw-like geometry to four Ca2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoAg(WO4)2 by Materials Project

HoAg(WO4)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ho3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ho–O bond distances ranging from 2.32–2.56 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded to six O2- atoms to form distorted edge-sharing WO6 octahedra. There are a spread of W–O bond distances ranging from 1.82–2.14 Å. In the second W6+ site, W6+ is bonded to six O2- atoms to form distorted edge-sharing WO6 octahedra. There are a spread of W–O bond distances ranging from 1.81–2.21 Å. Ag1+ is bonded in a 2-coordinate geometry to eight O2- atoms. There are a spread of Ag–O bond distances ranging from 2.34–2.98 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ho3+, two W6+, and one Ag1+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+, one W6+, and one Ag1+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Ho3+, one W6+, and one Ag1+ atom. In the fourth O2- site, O2- is bonded to three W6+ and one Ag1+ atom to form distorted edge-sharing OAgW3 tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ho3+, one W6+, and one Ag1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Vertical Architecture Solution-Processed Quantum Dot Photodetectors with Amorphous Selenium Hole Transport Layer

Colloidal quantum dots (CQDs) provide wide spectral tunability and high absorption coefficients owing to quantum confinement and large oscillator strengths, which along with solution processability, allow a facile, low-cost, and room-temperature deposition technique for the fabrication of photonic devices. However, many solution-processed CQD photodetector devices demonstrate low specific-detectivity and slow temporal response. To achieve improved photodetector characteristics, limiting carrier recombination and enhancing photogenerated carrier separation are crucial. In this study, we develop and present an alternate vertical-stack photodetector wherein we use a solution-processed quantum dot photoconversion layer coupled to an amorphous selenium (a-Se) wide-bandgap charge transport layer that is capable of exhibiting single-carrier hole impact ionization and is compatible with active-matrix readout circuitry. This a-Se chalcogenide transport layer enables the fabrication of high-performance and reliable solution-processed quantum dot photodetectors, with enhanced charge extraction capabilities, high specific detectivity (D* ~ 0.5–5 × 10 12 Jones), fast 3 dB electrical bandwidth (3 dB BW ~ 22 MHz), low dark current density (J D ~ 5–10 pA/cm 2 ), low noise current (i n ~ 20–25 fW/Hz 1/2 ), and high linear dynamic range (LDR ~130–150 dB) across the measured visible electromagnetic spectrum (~405–656 nm).

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2020

Theoretical search for possible Li–Ni–B crystal structures using an adaptive genetic algorithm

The structural diversity of rare-earth and transition metal borides indicates that alkali-transition metal borides (A-T-B) show tremendous promise in exhibiting a variety of crystal structures with different dimensionalities of T-B frameworks. On the other hand, the A-T-B ternary systems are severely underexplored because of the synthetic challenges associated with their preparation. Accurate and efficient computational predictions of low-energy stable and metastable phases can identify the optimal compositions of the hypothetical compounds in the A-T-B systems to guide the synthesis. As such, in this work, we have computationally discovered several new phases in the Li–Ni–B ternary system. The newly discovered LiNiB, Li 2 Ni 3 B, and Li 2 NiB phases expand the existing theoretical database, and the convex-hull surface of Li–Ni–B has been re-constructed. The lowest energy structure of the LiNiB compound has been found by an adaptive genetic algorithm with layered motif, which matches with the experimentally determined structure. According to our electrochemical calculations, LiNiB and another predicted layered Li 2 NiB compounds have great potential as anode materials for lithium batteries. The Li 2 Ni 3 B compound with the space group P4 3 32 was predicted to crystallize in a cubic structure composed of distorted octahedral units of BNi 6 , which is isostructural to two noncentrosymmetric superconductors Li 2 Pd 3 B and Li 2 Pt 3 B. While we were unable to experimentally confirm the Li 2 Ni 3 B compound utilizing the hydride synthetic route, attempts to synthesize this compound by alternate methods remain highly desirable, considering its potential superconducting properties.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Basic Research Needs for Transformative Manufacturing

This report is based on a Basic Research Needs workshop for Transformative Manufacturing, which was held March 9 - 11, 2020. The focus of the workshop was to identify the basic science research priorities that could accelerate innovation to transform manufacturing in the future. This was the first workshop of its kind to examine how basic energy science can drive manufacturing forward and innovate new ways to manufacture goods. Five Priority Research Directions were identified that address these science challenges: (1) innovative synthetic approaches to enable scalable assembly of matter, (2) computational methods and theoretical models to transform how manufacturing processes are controlled, (3) new characterization tools that can handle the necessary complexity, scales, and processing speeds to meet manufacturing needs, (4) new science to address opportunities relevant to sustainable and energy efficient manufacturing, and (5) foundational approaches to co-design of materials, process, and products.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Magnetic structure of magnetoelectric multiferroic HoFeWO 6

The polar magnetic oxide, HoFeWO6, is synthesized, and its crystal structure, magnetic structure, and thermodynamic properties are investigated. HoFeWO 6 forms the polar crystal structure (space group Pna2 1 (#33)) due to the cation ordering of W 6+ and Fe 3+ . An antiferromagnetic transition at T N = 17 K is accompanied by a significant change in magnetic entropy with a value of ≈ 5 J kg -1 K-1 in a 70 kOe applied field. Temperature dependent neutron diffraction and magnetization data indicate that the Fe sublattice orders in a strongly non-collinear and non-coplanar arrangement below T N . The Fe ordering initially leads to induced ordering of the Ho spins such that the Ho spins also show behavior of long-range ordering that is evident from the neutron diffraction measurements. Below T ≈ 4 K, the Ho spins order independently and pull the Fe spins toward the direction of Ho spins. A comparison with the magnetic structures and corresponding ferroelectric properties of other members of RMWO 6 (R = Y, Sm-Tm, M = Cr, Fe, V) family indicate that the spontaneous polarization is due to the magnetic structure specific to the Fe sublattice through magnetoelectric coupling whereas the polarization is independent of the Ho sublattice.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Adsorption of Rare Earth Elements onto DNA-Functionalized Mesoporous Carbon

The recovery and separation of rare earth elements (REEs) are of national importance owing to the specific usages, high demand, and low supply of these elements. In this research, we have investigated the adsorption of rare earth elements onto DNA-functionalized mesoporous carbons with a BET surface area of 605 m2/g and a median mesopore width of 48 Å. Additionally, three types of single-stranded DNA, one with 100 base units of thymine, another with 20 units of thymine, and the third, a 2000 unit long DNA from salmon milt were grafted on the carboxylated mesoporous carbon surface. All of the DNA-functionalized mesoporous carbons demonstrated higher adsorption of REEs compared to pristine mesoporous carbon and DNA grafted with 100 units of thymine demonstrated slightly higher adsorbed amounts compared to others. Pure neodymium (Nd(III)) adsorption in the aqueous phase demonstrated an adsorbed amount of 110.4 mg/g with respect to the initial concentration of 500 mg/g. A pH variation study with pure Nd(III) demonstrated that the adsorbed amount is higher at elevated pH compared to that at lower pH, thereby suggesting possible recovery at lower pH. Adsorption of a mixture of 16 REEs, including Sc, Lu, Tm, Yb, Er, Ho, Tb, Dy, Y, Eu, Gd, Sm, Ce, Nd, Pr, and La revealed that the adsorbed amount increased with an increase in the atomic weight and metallic radii of elements within the lanthanides. The calculation of the distribution coefficients for all of the equilibrium adsorption amounts suggested that adsorption is more effective in the lower concentration region. The Nd L3-edge X-ray absorption near edge structure (XANES) confirmed a 3+ oxidation state of Nd in the adsorbed phase. The extended X-ray absorption fine structure (EXAFS) confirmed the local atomic structure relaxation of Nd complexes in the adsorbed phase and shortening of the Nd–O bond distance by about 0.03–0.04 Å, which may be associated with their local complexation at the carbon surface.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Perturbation of Tropical Stratospheric Ozone Through Homogeneous and Heterogeneous Chemistry Due To Pinatubo

Abstract The Pinatubo eruption in 1991 injected 10–20 Tg SO 2 into the stratosphere, which formed sulfate aerosols through oxidation. Our modeling results show that volcanic heating significantly perturbs the heterogeneous and homogeneous chemistry including NO x and HO x catalytic cycles in the tropical stratosphere. The simulated tropical chemical ozone tendency is positive at 20 mb while negative at 10 mb in the tropics. The simulated ozone chemical tendency is of the same magnitude as the dynamical ozone tendency caused by the accelerated tropical upwelling, but with the opposite sign. Our study finds that the tropical ozone chemical tendency due to homogeneous chemistry becomes more important than heterogeneous chemistry 3 months after eruption. Sensitivity simulations further suggest that the tropical ozone tendency through heterogeneous chemistry is saturated when the injected amount exceeds 2 Tg.

54 ENVIRONMENTAL SCIENCES↗