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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on PmMg2 by Materials Project

Mg2Pm is Cubic Laves structured and crystallizes in the trigonal R32 space group. The structure is three-dimensional. there are two inequivalent Mg sites. In the first Mg site, Mg is bonded to six equivalent Mg and six equivalent Pm atoms to form a mixture of edge, face, and corner-sharing MgPm6Mg6 cuboctahedra. All Mg–Mg bond lengths are 3.05 Å. All Mg–Pm bond lengths are 3.58 Å. In the second Mg site, Mg is bonded to six Mg and six equivalent Pm atoms to form a mixture of edge, face, and corner-sharing MgPm6Mg6 cuboctahedra. All Mg–Mg bond lengths are 3.06 Å. There are four shorter (3.58 Å) and two longer (3.59 Å) Mg–Pm bond lengths. Pm is bonded in a 12-coordinate geometry to twelve Mg and four equivalent Pm atoms. All Pm–Pm bond lengths are 3.74 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

An Initial Evaluation of the Elevated-Temperature Cyclic Properties of Optimized 316H Stainless Steel Fabricated by Powder Metallurgy Hot Isostatic Pressing

Powder metallurgy hot isostatic pressing (PM-HIP) is a mature advanced manufacturing technology, which can consolidate metallic powder under high temperature and pressure to generate near-net shape components. This process can lower production costs and reduce component lead times for nuclear reactor construction and can be readily deployed in the near term for microreactor components because of their smaller size. The purpose of this work is to continue the evaluation of elevated-temperature cyclic material properties for PM-HIP 316H stainless steel. Prior scoping results have shown that the commercially procured PM-HIP stainless-steel materials have reduced creep-fatigue performance compared to wrought 316 stainless steels. To better understand how PM-HIP processed material properties compare to traditional manufacturing methods, additional billets of PM-HIP 316H stainless steel were procured and tested. This testing is necessary to understand how elevated-temperature properties are influenced by the PM-HIP process and what data are needed for incorporating PM HIP 316H into the American Society of Mechanical Engineers Boiler Pressure Vessel Code, Section III, Division 5 for high temperature reactor construction. Specifically, an additional PM-HIP 316H stainless steel billet with lower oxygen and nitrogen concentrations was fabricated by the Nuclear Advanced Manufacturing Research Centre of the United Kingdom and tested to understand if elevated-temperature cyclic properties can be improved. The creep-fatigue resistance of the material from this new billet did not show appreciable improvement compared to prior testing.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2026

A comparison of wrought and powder metallurgical FeCrAl claddings under simulated LWR accident transients

Iron-chromium-aluminum (FeCrAl) alloys are potential accident tolerant fuel (ATF) cladding candidates for light-water reactors but are difficult to fabricate as thin-walled tubes via conventional cast-and-wrought routes. Powder metallurgy (PM) offers a manufacturing alternative with improved compositional control, but its transient accident performance has not been directly benchmarked against wrought variants. This study evaluates the burst behavior of commercially developed PM-processed FeCrAl alloys, PM-C26M (Fe-12Cr-6Al-2Mo) and the high precipitate density FA-SMT (Fe-22Cr-5Al-3Mo), under simulated light-water reactor accident transient conditions. Burst testing was conducted using the Severe Accident Test Station with heating rates of 5 °C/s and 50 °C/s and internal pressures ranging from 25 MPa to 100 MPa. PM-C26M reproduced wrought C26M burst behavior within 7–37 °C across the stress range, indicating that PM processing does not compromise transient strength. FA-SMT exhibited markedly higher burst temperatures and reduced heating-rate sensitivity, consistent with its engineered precipitate strengthening. FA-SMT rupture exhibited axial "unzipping" rather than the lateral tearing characteristic of PM- and wrought C26M. Post-test EBSD and fractography indicate that this behavior is strongly correlated with strain-gated intergranular void nucleation associated with the dense precipitate architecture of FA-SMT, a response absent in the comparatively clean PM-C26M matrix and consistent with rupture morphologies reported for oxide-dispersion strengthened (ODS) FeCrAl of similar base-matrix chemistry to PM-C26M. These findings highlight the potential of powder metallurgy as a viable fabrication route for ATF claddings from an accident performance standpoint.

Bell, Sam [ORNL] (ORCID:0000000251905657)↗
DOE OSTI2024

Stellar populations and merger rates of brightest cluster galaxies a billion years ago: SDSS MaNGA IFU spectroscopy

ABSTRACT We investigate the spectroscopic properties of 85 brightest cluster galaxies (BCGs) and their companions observed with the SDSS MaNGA integral field unit. Galaxy redshifts are between 0.08 < z < 0.15, allowing for a field-of-view up to 80 × 80 kpc. For the main galaxies: the average age of the BCG cores is 7.66$\, \pm \,$1.36 Gyr with no significant gradient out to $2\, R_ {e}$; the average metallicity of the BCG cores is $[Z/H]=0.23\, \pm \, 0.03$ with a negative gradient of Δ[Z/H]/Δ(R/Re) = –0.14$\, \pm \, 0.09$ which flattens beyond $1.2\, R_ {e}$. Velocity dispersion gradients are mostly flat, but a few positive slopes are seen in the most massive galaxies. Emission lines are present in 12 of the BCGs, most often confined to the central $\sim 2\,$ kpc with emission line ratios well-described by a LINER or AGN excitation source. There are 78 companion galaxies identified and 9 have nebular emission lines that indicate recent star formation. The companions with flux ratios of 4:1 and 20:1 within 30 kpc of their BCG’s core are studied. The companion galaxies have a median age of 7.65$\, \pm \,$1.55 Gyr and are high-metallicity systems, with a median [Z/H] = 0.17 ± 0.07. Close spectroscopic companions with higher merging probabilities have an average merging time of 0.5 ± 0.2 Gyr. The average merger rate is 0.08$\, \pm \, 0.12 \,$ Gyr−1 for 4:1 companions and 0.26$\, \pm \, 0.22 \,$ Gyr−1 for 20:1 companions, allowing for an increase in mass of 2.3$\, \pm \,$3.4 per cent Gyr−1 and 3.5$\, \pm \,$3.2 per cent Gyr−1, respectively.

Edwards, Louise O. V. (ORCID:000000029135997X)↗
DOE OSTI2025

Precision measurement of the B0 meson lifetime using B0→J/ψK∗0 decays with the ATLAS detector

A measurement of the B0$$B^{0}$$ meson lifetime using B0→J/ψK∗0$$ B^{0} \rightarrow J/\psi K^{*0} $$ decays in data from 13 TeV$$\text {TeV}$$ proton–proton collisions with an integrated luminosity of 140fb-1$$ 140~\mathrm {fb^{-1}} $$ recorded by the ATLAS detector at the LHC is presented. The measured effective lifetime is τ=1.5053±0.0012(stat.)±0.0035(syst.)ps.$$ \tau = 1.5053\pm 0.0012~\mathrm {(stat.)} \pm 0.0035~\mathrm {(syst.)~ps}. $$The average decay width extracted from the effective lifetime, using parameters from external sources, is Γd=0.6639±0.0005(stat.)±0.0016(syst.)±0.0038(ext.)ps-1,$$\begin{aligned} \Gamma _d = 0.6639\pm 0.0005~\mathrm {(stat.)} \pm 0.0016~\mathrm {(syst.)}\\ \pm 0.0038~\text {(ext.)} \text {~ps}^{-1}, \end{aligned}$$where the uncertainties are statistical, systematic and from external sources. The earlier ATLAS measurement of Γs$$\Gamma _s$$ in the Bs0→J/ψϕ$$B^{0}_{s} \rightarrow J/\psi \phi $$ decay was used to derive a value for the ratio of the average decay widths Γd$$\Gamma _d$$ and Γs$$\Gamma _s$$ for B0$$B^{0} $$ and Bs0$$B^{0}_{s} $$ mesons respectively, of ΓdΓs=0.9905±0.0022(stat.)±0.0036(syst.)±0.0057(ext.).$$ \frac{\Gamma _d }{\Gamma _s } = 0.9905\pm 0.0022~\text {(stat.)} \pm 0.0036~\text {(syst.)} \pm 0.0057~\text {(ext.)}. $$The measured lifetime, average decay width and decay width ratio are in agreement with theoretical predictions and with measurements by other experiments. This measurement provides the most precise result of the effective lifetime of the B0$$B^{0}$$ meson to date.

Aad, G↗
DOE OSTI2024

Ducted Fuel Injection And Cooled Spray Technologies For Particulate Control In Heavy-duty Diesel Engines (Final Report)

Cooled Spray (CS) and Ducted Fuel Injection (DFI) are in-cylinder technologies for diesel engines that can reduce particulate matter and soot emissions and data has been published showing that these technologies can reduce soot emissions by 75-100% for some engines at some operating conditions. However, little is known about scaling the devices for engine size. Additionally, the performance of either technology over the engine duty cycle has not been explored. This project addresses both of these points through single-cylinder engine investigations. The objectives of this project are to provide details about dimensional scaling of these devices and to demonstrate 75% PM reduction over a range of operating conditions on a single-cylinder engine. Two engines were used for this project: a 125mm bore optically accessible engine at Sandia National Laboratories and a 168mm bore metal engine at Southwest Research Institute. The optical engine was used to study the performance of DFI and CS inserts for a large injector orifice diameter injector that is characteristic of a locomotive engine and to perform scaling studies for DFI. The metal engine was used to perform scaling and alignment studies for CS and to evaluate the technology for both EGR and non-EGR engines over the engine operating map. Modifications were required for both engines to accept the prototype inserts being tested. The optical engine required a new fuel injector, cylinder head and piston so that tests could be run at the pressures and engine speeds required. Additionally, a novel rotating stage was designed for the optical engine to simplify alignment of the modules. The metal engine required a modified cylinder head to accept CS inserts and a modified piston to provide additional space around the fuel injector for the CS inserts. Tests on the optical engine showed that DFI reduces PM emissions for both small injector orifices (0.170mm diameter) and large injector orifices (0.290mm). For high load testing, the DFI modules were not as effective as at low load testing, but it was acknowledged that minimal geometric optimization was performed and more improvements may be possible. Comparing DFI to CS and conventional diesel combustion (CDC), DFI performed better than CS or CDC. The CS geometries used in these studies may not be ideal for that engine and additional modifications likely would improve performance. Tests on the metal engine showed PM reductions as high has 80% at some operating conditions with duty-cycle PM reductions of ~50% for EGR and non-EGR configurations. The CS testing on the metal engine showed that chamfering of the fuel passage inlet either through hydro-erosion or mechanical grinding provided significant improvements in the PM reduction capabilities of the insert. Additionally, alignment sensitivities were explored and the data show that the tolerance to misalignment is approximately 0.05 to 0.1mm for the inserts that were studied here. Air-fuel ratio was shown to be important in the effectiveness of the CS inserts. In several tests, it was shown that the CS inserts are more effective at reducing the PM for high-AFR operating conditions compared to low AFR conditions. In summary, multiple designs were evaluated on both engines. It was found that for the conditions and configurations studied here, a fuel passage diameter of ~2.5mm performed best overall. Significant duty-cycle PM reductions are possible using these technologies and sensitivities to AFR, alignment fuel passage diameter and inlet fuel passage shaping were explored and are reported here. More PM reduction may be possible with improved geometric design and attention to alignment practices.

02 PETROLEUM↗
NASA NTRS2010

A Singular Perturbation Approach for Time-Domain Assessment of Phase Margin

This paper considers the problem of time-domain assessment of the Phase Margin (PM) of a Single Input Single Output (SISO) Linear Time-Invariant (LTI) system using a singular perturbation approach, where a SISO LTI fast loop system, whose phase lag increases monotonically with frequency, is introduced into the loop as a singular perturbation with a singular perturbation (time-scale separation) parameter Epsilon. First, a bijective relationship between the Singular Perturbation Margin (SPM) max and the PM of the nominal (slow) system is established with an approximation error on the order of Epsilon(exp 2). In proving this result, relationships between the singular perturbation parameter Epsilon, PM of the perturbed system, PM and SPM of the nominal system, and the (monotonically increasing) phase of the fast system are also revealed. These results make it possible to assess the PM of the nominal system in the time-domain for SISO LTI systems using the SPM with a standardized testing system called "PM-gauge," as demonstrated by examples. PM is a widely used stability margin for LTI control system design and certification. Unfortunately, it is not applicable to Linear Time-Varying (LTV) and Nonlinear Time-Varying (NLTV) systems. The approach developed here can be used to establish a theoretical as well as practical metric of stability margin for LTV and NLTV systems using a standardized SPM that is backward compatible with PM.

Zhu, J. Jim↗
NASA NTRS2015

Experimental Investigation on Acousto-Ultrasonic Sensing Using Polarization-Maintaining Fiber Bragg Gratings

This report discusses the guided Lamb wave sensing using polarization-maintaining (PM) fiber Bragg grating (PM-FBG) sensor. The goal is to apply the PM-FBG sensor system to composite structural health monitoring (SHM) applications in order to realize directivity and multi-axis strain sensing capabilities while using reduced number of sensors. Comprehensive experiments were conducted to evaluate the performance of the PM-FBG sensor in a composite panel structure under different actuation frequencies and locations. Three Macro-Fiber-Composite (MFC) piezoelectric actuators were used to generate guided Lamb waves and they are oriented at 0, 45, and 90 degrees with respect to PM-FBG axial direction, respectively. The actuation frequency was varied from 20kHz to 200kHz. It is shown that the PM-FBG sensor system is able to detect high-speed ultrasound waves and capture the characteristics under different actuation conditions. Both longitudinal and lateral strain components in the order of nano-strain were determined based on the reflective intensity measurement data from fast and slow axis of the PM fiber. It must be emphasized that this is the first attempt to investigate acousto-ultrasonic sensing using PM-FBG sensor. This could lead to a new sensing approach in the SHM applications.

Wang, Gang↗
NASA NTRS2016

Experimental Investigation on Acousto-ultrasonic Sensing Using Polarization-Maintaining Fiber Bragg Gratings

This report discusses the guided Lamb wave sensing using polarization-maintaining (PM) fiber Bragg grating (PM-FBG) sensor. The goal is to apply the PM-FBG sensor system to composite structural health monitoring (SHM) applications in order to realize directivity and multi-axis strain sensing capabilities while reducing the number of sensors. Comprehensive experiments were conducted to evaluate the performance of the PM-FBG sensor attached to a composite panel structure under different actuation frequencies and locations. Three Macro-Fiber-Composite (MFC) piezoelectric actuators were used to generate guided Lamb waves that were oriented at 0, 45, and 90 degrees with respect to PM-FBG axial direction, respectively. The actuation frequency was varied from 20kHz to 200kHz. It was shown that the PM-FBG sensor system was able to detect high-speed ultrasound waves and capture the characteristics under different actuation conditions. Both longitudinal and lateral strain components in the order of nano-strain were determined based on the reflective intensity measurement data from fast and slow axis of the PM fiber. It must be emphasized that this is the first attempt to investigate acouto-ultrasonic sensing using PM-FBG sensor. This could lead to a new sensing approach in the SHM applications. Nomenclature.

Wang, Gag↗
NASA NTRS2018

Performance of the Center-Of-Curvature Optical Assembly During Cryogenic Testing of the James Webb Space Telescope

The James Webb Space Telescope (JWST) primary mirror (PM) is 6.6 meters in diameter and consists of 18 hexagonal segments, each 1.5 meters point-to-point. Each segment has a 6 degree-of-freedom hexapod actuation system and a radius-of-curvature (ROC) actuation system. The full telescope was tested at its cryogenic operating temperature at Johnson Space Center (JSC) in 2017. This testing included center-of-curvature measurements of the PM wavefront error using the Center-of-Curvature Optical Assembly (COCOA), along with the Absolute Distance Meter Assembly (ADMA). The COCOA included an interferometer, a reflective null, an interferometer-null calibration system, coarse and fine alignment systems, and two displacement measuring interferometer systems. A multiple-wavelength interferometer was used to enable alignment and phasing of the PM segments. By combining measurements at two laser wavelengths, synthetic wavelengths up to 15 millimeters could be achieved, allowing mirror segments with millimeter-level piston errors to be phased to the nanometer level. The ADMA was used to measure and set the spacing between the PM and the focus of the COCOA null (i.e., the PM center-of-curvature) for determination of the ROC. This paper describes the COCOA, the PM test setup, the testing performed, the test results, and the performance of the COCOA in aligning & phasing the PM segments and measuring the final PM wavefront error.

JWST↗
NASA NTRSDate not supplied

A Novel Machine Learning Method for Surface PM2.5 Estimations from Geostationary Satellites

Particulate matter (PM) with a diameter of less or equal to 2.5 μm, known as PM , affects human health as it penetrates the respiratory system. The Environmental Protection Agency (EPA) measures the atmospheric concentration of PM using air quality monitors stationed throughout the Continental United States (CONUS). Such measurements are points on a spatial domain and therefore, might not be representative of the air quality at nearby areas considering that the composition of the atmosphere is highly variable from place to place. Satellite based AOD permits a spatially uniform means of estimating PM and new geostationary satellites provide high temporal and spatial resolution estimation of AOD. However, the concentration of PM is non-linearly dependent on other atmospheric parameters that include relative humidity, temperature, and height of the planetary boundary layer. This information may be estimated at similar spatial and temporal resolutions as AOD from numerical modeling such as from the National Oceanic and Atmospheric Administration’s (NOAA) High Resolution Rapid Refresh (HRRR) model which resolves near real-time atmospheric conditions over the CONUS. The estimation of PM concentration is a multi-parametric problem that considers the effect of temporal dependencies among the different parameters. Deep learning approaches are appropriate for such complex estimation problems as they intrinsically capture relations among multiple non-linear parameters. This study compares deep-learning methods to traditional regression analysis to demonstrate the capabilities of these methods in predicting PM2.5 concentrations. Additionally, a novel ensemble learning approach is employed to identify scientific processes that could further improve the estimation of PM concentration. Utilizing Long Short-Term Memory (LSTM) neural networks, which are suitable for multivariate time series estimation problems as they are capable of learning long-term dependencies, individual models are created for each EPA station and trained on the aforementioned dataset collocated over each station. Individual station models are merged if the model's performance is improved by reducing the root mean squared error (RMSE) metric. This ensemble training method ultimately reduces the RMSE value. Evaluation of these results provide insights into physical processes and related observable parameters that may contribute to PM concentrations. Identified parameters evaluated to be statistically different between the merged and unmerged models are expected to improve overall performance. These new parameters are then utilized for reevaluation of the deep learning methods with an extreme gradient boosting model with an RMSE of 5.5 providing the best results.

George Priftis↗
DOE OSTI2020

Materials Data on PmHo3 by Materials Project

Ho3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded to eight Ho and four equivalent Pm atoms to form HoPm4Ho8 cuboctahedra that share corners with four equivalent PmHo12 cuboctahedra, corners with fourteen HoPm4Ho8 cuboctahedra, edges with six equivalent PmHo12 cuboctahedra, edges with twelve HoPm4Ho8 cuboctahedra, faces with four equivalent PmHo12 cuboctahedra, and faces with sixteen HoPm4Ho8 cuboctahedra. There are a spread of Ho–Ho bond distances ranging from 3.53–3.66 Å. There are two shorter (3.54 Å) and two longer (3.63 Å) Ho–Pm bond lengths. In the second Ho site, Ho is bonded to eight Ho and four equivalent Pm atoms to form HoPm4Ho8 cuboctahedra that share corners with four equivalent PmHo12 cuboctahedra, corners with fourteen HoPm4Ho8 cuboctahedra, edges with six equivalent PmHo12 cuboctahedra, edges with twelve HoPm4Ho8 cuboctahedra, faces with four equivalent PmHo12 cuboctahedra, and faces with sixteen HoPm4Ho8 cuboctahedra. There are a spread of Ho–Ho bond distances ranging from 3.53–3.66 Å. There are two shorter (3.54 Å) and two longer (3.63 Å) Ho–Pm bond lengths. In the third Ho site, Ho is bonded to eight Ho and four equivalent Pm atoms to form HoPm4Ho8 cuboctahedra that share corners with four equivalent PmHo12 cuboctahedra, corners with fourteen HoPm4Ho8 cuboctahedra, edges with six equivalent PmHo12 cuboctahedra, edges with twelve HoPm4Ho8 cuboctahedra, faces with four equivalent PmHo12 cuboctahedra, and faces with sixteen HoPm4Ho8 cuboctahedra. There are two shorter (3.54 Å) and two longer (3.63 Å) Ho–Pm bond lengths. Pm is bonded to twelve Ho atoms to form PmHo12 cuboctahedra that share corners with six equivalent PmHo12 cuboctahedra, corners with twelve HoPm4Ho8 cuboctahedra, edges with eighteen HoPm4Ho8 cuboctahedra, faces with eight equivalent PmHo12 cuboctahedra, and faces with twelve HoPm4Ho8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Si by Materials Project

Pm3Si is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Si atoms to form distorted PmPm8Si4 cuboctahedra that share corners with twelve equivalent PmPm8Si4 cuboctahedra, edges with eight equivalent SiPm12 cuboctahedra, edges with sixteen equivalent PmPm8Si4 cuboctahedra, faces with four equivalent SiPm12 cuboctahedra, and faces with fourteen equivalent PmPm8Si4 cuboctahedra. All Pm–Pm bond lengths are 3.36 Å. All Pm–Si bond lengths are 3.36 Å. Si is bonded to twelve equivalent Pm atoms to form SiPm12 cuboctahedra that share corners with twelve equivalent SiPm12 cuboctahedra, edges with twenty-four equivalent PmPm8Si4 cuboctahedra, faces with six equivalent SiPm12 cuboctahedra, and faces with twelve equivalent PmPm8Si4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Tl by Materials Project

Pm3Tl is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Tl atoms to form distorted PmPm8Tl4 cuboctahedra that share corners with twelve equivalent PmPm8Tl4 cuboctahedra, edges with eight equivalent TlPm12 cuboctahedra, edges with sixteen equivalent PmPm8Tl4 cuboctahedra, faces with four equivalent TlPm12 cuboctahedra, and faces with fourteen equivalent PmPm8Tl4 cuboctahedra. All Pm–Pm bond lengths are 3.51 Å. All Pm–Tl bond lengths are 3.51 Å. Tl is bonded to twelve equivalent Pm atoms to form TlPm12 cuboctahedra that share corners with twelve equivalent TlPm12 cuboctahedra, edges with twenty-four equivalent PmPm8Tl4 cuboctahedra, faces with six equivalent TlPm12 cuboctahedra, and faces with twelve equivalent PmPm8Tl4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Y by Materials Project

Pm3Y is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Y atoms to form PmPm8Y4 cuboctahedra that share corners with twelve equivalent PmPm8Y4 cuboctahedra, edges with eight equivalent YPm12 cuboctahedra, edges with sixteen equivalent PmPm8Y4 cuboctahedra, faces with four equivalent YPm12 cuboctahedra, and faces with fourteen equivalent PmPm8Y4 cuboctahedra. All Pm–Pm bond lengths are 3.63 Å. All Pm–Y bond lengths are 3.63 Å. Y is bonded to twelve equivalent Pm atoms to form YPm12 cuboctahedra that share corners with twelve equivalent YPm12 cuboctahedra, edges with twenty-four equivalent PmPm8Y4 cuboctahedra, faces with six equivalent YPm12 cuboctahedra, and faces with twelve equivalent PmPm8Y4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmPu3 by Materials Project

Pu3Pm is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Pu sites. In the first Pu site, Pu is bonded to eight Pu and four equivalent Pm atoms to form PuPm4Pu8 cuboctahedra that share corners with four equivalent PmPu12 cuboctahedra, corners with fourteen PuPm4Pu8 cuboctahedra, edges with six equivalent PmPu12 cuboctahedra, edges with twelve PuPm4Pu8 cuboctahedra, faces with four equivalent PmPu12 cuboctahedra, and faces with sixteen PuPm4Pu8 cuboctahedra. There are a spread of Pu–Pu bond distances ranging from 3.39–3.57 Å. There are two shorter (3.46 Å) and two longer (3.48 Å) Pu–Pm bond lengths. In the second Pu site, Pu is bonded to eight Pu and four equivalent Pm atoms to form PuPm4Pu8 cuboctahedra that share corners with four equivalent PmPu12 cuboctahedra, corners with fourteen PuPm4Pu8 cuboctahedra, edges with six equivalent PmPu12 cuboctahedra, edges with twelve PuPm4Pu8 cuboctahedra, faces with four equivalent PmPu12 cuboctahedra, and faces with sixteen PuPm4Pu8 cuboctahedra. All Pu–Pu bond lengths are 3.40 Å. There are two shorter (3.46 Å) and two longer (3.48 Å) Pu–Pm bond lengths. In the third Pu site, Pu is bonded to eight Pu and four equivalent Pm atoms to form PuPm4Pu8 cuboctahedra that share corners with four equivalent PmPu12 cuboctahedra, corners with fourteen PuPm4Pu8 cuboctahedra, edges with six equivalent PmPu12 cuboctahedra, edges with twelve PuPm4Pu8 cuboctahedra, faces with four equivalent PmPu12 cuboctahedra, and faces with sixteen PuPm4Pu8 cuboctahedra. There are two shorter (3.46 Å) and two longer (3.48 Å) Pu–Pm bond lengths. Pm is bonded to twelve Pu atoms to form PmPu12 cuboctahedra that share corners with six equivalent PmPu12 cuboctahedra, corners with twelve PuPm4Pu8 cuboctahedra, edges with eighteen PuPm4Pu8 cuboctahedra, faces with eight equivalent PmPu12 cuboctahedra, and faces with twelve PuPm4Pu8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Er by Materials Project

ErPm3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Er is bonded to twelve equivalent Pm atoms to form ErPm12 cuboctahedra that share corners with twelve equivalent ErPm12 cuboctahedra, edges with twenty-four equivalent PmPm8Er4 cuboctahedra, faces with six equivalent ErPm12 cuboctahedra, and faces with twelve equivalent PmPm8Er4 cuboctahedra. All Er–Pm bond lengths are 3.62 Å. Pm is bonded to four equivalent Er and eight equivalent Pm atoms to form PmPm8Er4 cuboctahedra that share corners with twelve equivalent PmPm8Er4 cuboctahedra, edges with eight equivalent ErPm12 cuboctahedra, edges with sixteen equivalent PmPm8Er4 cuboctahedra, faces with four equivalent ErPm12 cuboctahedra, and faces with fourteen equivalent PmPm8Er4 cuboctahedra. All Pm–Pm bond lengths are 3.62 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiPm3 by Materials Project

LiPm3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Li is bonded to twelve equivalent Pm atoms to form LiPm12 cuboctahedra that share corners with twelve equivalent LiPm12 cuboctahedra, edges with twenty-four equivalent PmLi4Pm8 cuboctahedra, faces with six equivalent LiPm12 cuboctahedra, and faces with twelve equivalent PmLi4Pm8 cuboctahedra. All Li–Pm bond lengths are 3.53 Å. Pm is bonded to four equivalent Li and eight equivalent Pm atoms to form PmLi4Pm8 cuboctahedra that share corners with twelve equivalent PmLi4Pm8 cuboctahedra, edges with eight equivalent LiPm12 cuboctahedra, edges with sixteen equivalent PmLi4Pm8 cuboctahedra, faces with four equivalent LiPm12 cuboctahedra, and faces with fourteen equivalent PmLi4Pm8 cuboctahedra. All Pm–Pm bond lengths are 3.53 Å.

36 MATERIALS SCIENCE↗