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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Tm(MnSi)2 by Materials Project

TmMn2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Tm–Si bond lengths are 2.99 Å. Mn+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing MnSi4 tetrahedra. All Mn–Si bond lengths are 2.35 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Tm3+, four equivalent Mn+2.50+, and one Si4- atom. The Si–Si bond length is 2.44 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(CuTe)3 by Materials Project

TmCu3Te3 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent Te2- atoms to form TmTe6 octahedra that share corners with twelve equivalent CuTe4 tetrahedra, edges with three equivalent TmTe6 octahedra, and edges with six equivalent CuTe4 tetrahedra. All Tm–Te bond lengths are 3.04 Å. Cu1+ is bonded to four equivalent Te2- atoms to form CuTe4 tetrahedra that share corners with four equivalent TmTe6 octahedra, corners with six equivalent CuTe4 tetrahedra, edges with two equivalent TmTe6 octahedra, and edges with three equivalent CuTe4 tetrahedra. The corner-sharing octahedra tilt angles range from 14–59°. There are a spread of Cu–Te bond distances ranging from 2.61–2.67 Å. Te2- is bonded in a 6-coordinate geometry to two equivalent Tm3+ and four equivalent Cu1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(Mo3S4)2 by Materials Project

TmMo6S8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Tm3+ is bonded in a body-centered cubic geometry to eight S2- atoms. There are two shorter (2.67 Å) and six longer (2.98 Å) Tm–S bond lengths. Mo+2.17+ is bonded to five S2- atoms to form a mixture of edge and corner-sharing MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.42–2.58 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to one Tm3+ and three equivalent Mo+2.17+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to one Tm3+ and four equivalent Mo+2.17+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(FeO2)2 by Materials Project

TmFe2O4 is Aluminum carbonitride-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent O2- atoms to form TmO6 octahedra that share corners with six equivalent FeO5 trigonal bipyramids and edges with six equivalent TmO6 octahedra. All Tm–O bond lengths are 2.26 Å. Fe+2.50+ is bonded to five O2- atoms to form FeO5 trigonal bipyramids that share corners with three equivalent TmO6 octahedra, corners with six equivalent FeO5 trigonal bipyramids, and edges with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 63°. There are a spread of Fe–O bond distances ranging from 1.99–2.18 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four equivalent Fe+2.50+ atoms to form OFe4 trigonal pyramids that share corners with four equivalent OTm3Fe tetrahedra, corners with six equivalent OFe4 trigonal pyramids, and edges with three equivalent OFe4 trigonal pyramids. In the second O2- site, O2- is bonded to three equivalent Tm3+ and one Fe+2.50+ atom to form OTm3Fe tetrahedra that share corners with nine equivalent OTm3Fe tetrahedra, corners with four equivalent OFe4 trigonal pyramids, and edges with three equivalent OTm3Fe tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Shear Assisted Processing and Extrusion (ShAPE) of Aluminum Alloy 7075, 2024, and Al-12.4TM

The most common aluminum alloys utilized in the aerospace industry are 7075 and 2024 due to their high strength-to-weight ratio compared to advanced high strength steels and other aluminum alloys. Despite excellent performance, these aluminum alloys have seen limited use outside of the aerospace industry due in part to high cost. If high-performance aluminum extrusions could be made more cost effectively by eliminating energy intensive process steps typical of conventional extrusion, then numerous opportunities exist for more widespread adoption. A key reason for the high cost of 7075 and 2024 extrusions (25-75% higher than 6061) is their slow extrusion speed. 7075 and 2024 are limited to 2 m/min and 3.5 m/min respectively, in contrast to 6061 which can be extruded at 20–80 m/min. In addition to slow speed, aluminum alloys require numerous thermal treatments throughout the extrusion process including homogenization and pre-heating prior to extrusion, and solution heat treating and artificial aging after extrusion. Each of these steps contribute to the total energy consumed during manufacturing of extruded components. This project investigates the use of ShAPE to improve extrusion speed and reduce, or even eliminate, the typical thermal treatments for high strength aluminum alloys, all while improving material performance. The overarching goal of this project was to demonstrate that Shear Assisted Processing and Extrusion (ShAPE) can manufacture high-performance aluminum alloy tubing with lower manufacturing energy and improved mechanical properties compared to conventional extrusion. Unlike conventional extrusion where the billet is rammed against a stationary die using a strictly linear motion, the ShAPE process superimposes a rotational shear force by spinning the die while the billet is plunged. Compared to conventional linear extrusion, the ShAPE process imparts significantly more strain into the feedstock material, which enables the formation of novel microstructures. These microstructures manifest an array of property and process improvements for extrusion of high-performance aluminum alloys. The following accomplishments were achieved for this project: Extrusion of 7075 at 12.2 meters/min compared to 2 meters/min for conventional extrusion; Elimination of 7075 billet homogenization (430 °C for 20 hours) which is required prior to conventional extrusion; Elimination of 7075 billet pre-heating (400 °C for 1 hour) in a separate furnace which is required prior to conventional extrusion; Achieved 7075-T6with yield strength = 595 MPa, ultimate tensile strength = 531MPa, and elongation = 17.4% for extrusions made from unhomogenized billets. Exceeds the ASTM and ASM standard, and typical industry values; Achieved 7075-T5 (i.e., no solution heat treatment) with yield strength = 588 MPa, ultimate tensile strength = 535 MPa, and elongation = 14.8% for extrusions made from homogenized billets; Extrusion of 2024 at 7.4 meters/min compared to 3.5 meters/min for conventional extrusion; Achieved 2024-T8510 yield strength = 522 MPa, ultimate strength = 510MPa, and elongation = 7.1% for extrusions made from wrought billets. Exceeds the ASTM and ASM standard, and typical industry values; Extrusion of Al-12.4TM high-performance aluminum powder directly into tubing, in a single step, which eliminates process steps typical of powder metallurgy extrusion.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Size-Dependent Photon Avalanching in Tm 3+ Doped LiYF 4 Nano, Micro, and Bulk Crystals

Photon avalanche (PA) is a highly nonlinear mode of upconversion that is characterized by 100–1000-fold increase in luminescence intensity upon minute increments of pumping power. The practical realization of numerous possible nano-bio-technology applications utilizing the PA phenomenon will require information on its susceptibility to the material volume and surface. In this report these parameters are investigated via experimental and theoretical PA. The two-color, highly nonlinear PA emission at 475 and 800 nm is clearly observed in bulk single crystal, individual microcrystals, and ensembles of colloidal core and core–shell nanoparticles of LiYF 4 host doped with either 3 or 8% of thulium ions. The properties of PA emission, such as PA nonlinearity, PA gain, PA intensity, and luminescence kinetics in these materials show dependence on crystal volume and surface quenching. Theoretical simulations provide understanding of key physical processes that influence PA performance. Moreover, photon avalanche single beam super-resolution imaging is realized for the first time in 3% Tm 3+ doped LiYF 4 core–shell nanoparticles. The obtained insights and predictions form a solid background for further development and applications of new optimized PA materials.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Syntheses and Crystal Structures of Rare-Earth Oxyapatites Ca 2 RE 8 (SiO 4 ) 6 O 2 (RE = Pr, Tb, Ho, Tm)

Four different rare-earth oxyapatites of Ca 2 RE 8 (SiO 4 ) 6 O 2 (RE = Pr, Tb, Ho, Tm) were synthesized using a solution-based method followed by drying, calcination, and high-temperature sintering in air. X-ray powder diffraction and Raman spectroscopy were performed on the synthesized oxyapatites. Here, the RE oxyapatites crystallize in the hexagonal space group P6 3 /m with similar unit cell parameters, increasing linearly with larger RE cations. The unit cell volumes increase linearly whereas the densities decrease nonlinearly with larger RE cations. Raman spectra showed intense bands of the symmetric bending and stretching modes of SiO 4 at ~ 400 and 860 cm -1 regions, respectively. The bands generally shifted to higher frequencies with smaller RE cations in the structures.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Using temperature and flow fields to detect gas leakage from canisters containing spent nuclear fuel: Applications to RAMM-TM

The multi-physics STAR-CCM+ code has been used to simulate the temperature and flow fields in canister gas leakage experiments conducted by using a 1/4.5-scale model storage cask. The simulations were conducted at Argonne National Laboratory’s Laboratory Computing Resource Center, utilizing high-performance computing resources. Development of STAR-CCM+ simulation models for the 1/4.5-scale model cask is described herein, followed by validation of the simulation results against experimental data. Canister depressurization and thermal response during gas leakage are discussed, along with analyses of the leakage path and allowable leakage rate. The insights gained from the STAR-CCM+ simulations and leakage analyses will help guide future experiments and actual industry applications of Argonne’s Remote Area Modular Monitoring system for canister surface temperature measurement (RAMM-TM) to enable effective aging management of spent fuel during extended dry storage, as well as help reduce risks to public safety and health and protect the environment.

Canister gas leakage↗
DOE OSTI2021

Synthesis and Transport Properties of the Family of Zintl Phases Ca 3 RESb 3 (RE = La–Nd, Sm, Gd–Tm, Lu): Exploring the Roles of Crystallographic Disorder and Core 4f Electrons for Enhancing Thermoelectric Performance

Zintl phases with complex crystal structures have been studied as promising candidate-materials for thermoelectric (TE) applications. Here, we report the syntheses of the family of rare-earth metal Zintl phases with the general formula Ca 4–x RE x Sb 3 (x ≈ 1; RE = La–Nd, Sm, Gd–Tm, Lu). The structural elucidation is based on refinements of single-crystal X-ray diffraction data for 12 unique chemical compositions. The cubic structure is confirmed as belonging to the anti-Th 3 P 4 structure type (space group I4¯3d, no. 220, Z = 4), where the Ca and RE atoms share the same atomic site with ca. 75% and 25% occupancies, respectively. Such crystallographic disordering of divalent Ca and trivalent RE atoms in the structure provides a pathway to intricate bonding. The latter, together with the presence of heavy elements such as Sb and the lanthanides, are expected to enhance the scattering probability of phonons, thereby leading to as low thermal conductivity κ as that of the ordered RE 4 Sb 3 . The drive of the hypothetical parent compound Ca 4 Sb 3 to be stabilized by alloying with rare-earth metals can be understood following the Zintl-Klemm concept, as the resultant formula may be rationalized as (Ca 2+ ) 3 RE 3+ (Sb 3– ) 3 , indicating the realization of closed-shell electronic configurations for all elements. This notion is confirmed by electronic structure calculations, which reveal narrow bandgaps E g = 0.77 and 0.53 eV for Ca 3 LaSb 3 and Ca 3 LuSb 3 , respectively. Additionally, the incorporation of RE atoms into the structure drives the phase into a state of a degenerate semiconductor with dominant hole charge carriers.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Inhomogeneous broadening and splitting of lines in spectra of YAG : Tm

The shape and fine structure of lines due to Tm{sup 3+} f −f electronic transitions in multifunctional Y{sub 3}Al{sub 5}O{sub 12} garnet crystals have been studied by high-resolution spectroscopy. The observed inhomogeneously broadened lines have a Lorentzian shape, suggesting that point defects make a predominant contribution to the inhomogeneous broadening. Moreover, Y{sub Al} antisite defects, which are formed during high-temperature melt growth, produce spectral satellites near the main lines. (paper)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Lasing characteristics of ZrO{sub 2} − Y{sub 2}O{sub 3} − Ho{sub 2}O{sub 3} crystals pumped by a Tm : LiYF{sub 4} laser

Two-micron lasing is obtained on the {sup 5}I{sub 7} → {sup 5}I{sub 8} transition of Ho{sup 3+} ions in ZrO{sub 2} − Y{sub 2}O{sub 3} −Ho{sub 2}O{sub 3} crystals upon resonance pumping into the {sup 5}I{sub 7} level of these ions by a pulsed laser based on a Tm : LiYF{sub 4} crystal. The efficiency of conversion of pump radiation incident on the crystal to laser radiation and the slope lasing efficiency at a pulse duration of 8 ms and a pulse repetition rate of 10 Hz were 25% and 28%, respectively. (paper)

36 MATERIALS SCIENCE↗
DOE OSTI2024

Evaluating the diffusion of Kr in UO 2 and ADOPT TM using time-of-flight elastic recoil detection analysis (ToF-erda)

A combination of 300 keV 84 Kr ion implantation and Time-of-Flight Elastic Recoil Detection Analysis is utilized to investigate the diffusion of Kr in UO 2 and ADOPT TM fuels. Composition depth-profiles on the nanometer scale were obtained, both for as-implanted samples and after annealing at 800°C for 1 hour. Observed drifts in the 84 Kr profiles could be associated with short-range diffusion mechanisms. The approach employed here provides the possibility to make direct comparisons with atomistic scale modelling data, and can be of service as a separate effect test in line with the Accelerated Fuel Qualification initiative.

ADOPT UO2↗
DOE OSTI2024

Optical characterizations of densely doped Tm 3+ :KYW crystals at low temperatures

Abstract We investigate the optical lifetime, decay characteristics, spectral linewidth and energy level properties of thulium ions doped in a KY(WO 4 ) 2 crystal at 4 K temperature. High doping concentration of thulium ions with inhomogeneous broadening allow us to study nonradiative behaviors, instantaneous spectral diffusion, and spectral power broadening in this solid-state material. The theoretical consideration of ion–ion interactions is shown to accurately characterize the absorption, decay and other spectral behaviors of Tm 3 + ions. We observe more than ten-fold reduction in the decay time of 3 H 4 state and about three-fold reduction in the spectral-hole lifetime as we approach the center of the inhomogeneous broadening, corresponding to higher optical densities.

Lei, Yisheng (ORCID:0009000410141189)↗
DOE OSTI2023

Probing triaxiality beyond the proton drip line: Spectroscopy of Tm 147

Two triaxial states of the proton-decaying nucleus 147 Tm were studied via a comparison of experimental data to results obtained through nonadiabatic quasiparticle calculations. The experimental data were collected in a recoil-decay tagging study using the vacuum-mode recoil separator MARA coupled with the JUROGAM3 $\gamma$-ray spectrometer. The previously proposed level scheme above the triaxial 11/2 - (π⁢ℎ 11/2 ) ground state was confirmed, and the level structure was expanded to cover the states above the weakly populated proton-emitting 5/2 + (πd 5/2 ) isomeric state. Further, it was found that the isomeric state is also triaxial, and possibly more deformed than the ground state.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Benchmarking the Suitability of Novec$^{\mathrm{TM}}$ 4710 for Application in Flux Compression Generators

Here, an experimental study evaluated the feasibility of replacing traditional insulating gases such as SF 6 with C 4 F 7 N (3M TM , Novec 4710) in flux compression generator (FCG) applications. Currently available data indicate that Novec 4710 could offer certain performance benefits over SF 6 . However, the available literature is focused on low frequency (50–60 Hz) and dc at static pressures. To evaluate the performance of Novec 4710 under the pulsed dynamic pressure and temperature conditions found in an FCG, we report a performance comparison between three sets of identical FCGs using air, SF 6 , and Novec 4710 as the insulating gas. The generators used in this study had a single stage, directly seeded design with an armature diameter of 25 mm and a stator diameter of 46 mm. To highlight the performance of the different gases rather than any wire insulation, the stator was constructed with uninsulated wire. Furthermore, the generators were seeded aggressively, making the performance difference between the different gases more apparent. The performance was monitored with a pair of differential Rogowski coils that captured the generators’ di / dt while also using high-speed videography to capture possible gaseous breakdown signatures. The data gathered during this study indicate that Novec 4710 performs at least as well as SF 6 in FCG applications, if not significantly better.

42 ENGINEERING↗
DOE OSTI2020

Experimental validation of color rendition specification criteria based on ANSI/IES TM-30-18

An experiment was conducted to examine color preference specification criteria. Twenty-five participants each evaluated 90 lighting scenes in a room filled with objects. The lighting scenes included nine chromaticity groups, each with 10 systematically-varied color rendition conditions designed to meet or not meet previously proposed color preference specification criteria using ANSI/IES TM-30-18 Rf, Rcs,h1, and Rg. The color rendition conditions did not meet the criterion for none, one, two, or all three of these measures. Participants, who chromatically adapted to each chromaticity group, rated the objects’ color appearance on eight-point scales for saturated-dull, normal-shifted, and like-dislike (preference), as well as a binary for acceptable or unacceptable. The findings corroborate past work, but also indicate that color preference criteria could be adjusted slightly to improve performance, with Tier A having Rf = 78, Rg = 95, and -1% = Rcs,h1 = 15%, Tier B having Rf = 74, Rg = 92, and -7% = Rcs,h1 = 19%, and Tier C having Rf = 70, Rg = 89, -12% = Rcs,h1 = 23%. A companion regression analysis shows models based on Rf, Rg, and Rcs,h1 were superior in predicting color preference compared to those using other measures of color rendition.

Royer, Michael P.↗
DOE OSTI2020

Evaluation of Uplight Energy Saving Actions Using ResStock TM (Summary of Results)

As part of a portfolio of product offerings, Uplight produces energy savings estimates to inform a utility’s residential customers of the expected benefits that would arise from adopting energy efficiency measures, which are termed “energy saving actions. ”Uplight’s current practice is to use a proprietary building simulation model to estimate energy and cost benefits from these actions, as discussed in Maguire et al. Uplight requested that the National Renewable Energy Laboratory (NREL) provide an independent estimate of the energy savings for a defined list of energy saving actions. NREL performed this study using two established building energy simulation tools: EnergyPlus ® ( EnergyPlus ) and ResStock TM .(

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗