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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on LiSbWO7 by Materials Project

LiWSbO7 crystallizes in the orthorhombic Imma space group. The structure is three-dimensional. Li is bonded in a distorted linear geometry to four O atoms. There are two shorter (1.95 Å) and two longer (2.55 Å) Li–O bond lengths. W is bonded to six O atoms to form WO6 octahedra that share corners with two equivalent WO6 octahedra and corners with four equivalent SbO6 octahedra. The corner-sharing octahedra tilt angles range from 34–41°. There is four shorter (1.94 Å) and two longer (1.95 Å) W–O bond length. Sb is bonded to six O atoms to form SbO6 octahedra that share corners with two equivalent SbO6 octahedra and corners with four equivalent WO6 octahedra. The corner-sharing octahedra tilt angles range from 41–49°. There are four shorter (1.99 Å) and two longer (2.03 Å) Sb–O bond lengths. There are four inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to two equivalent Li atoms. In the second O site, O is bonded in a distorted bent 150 degrees geometry to one W and one Sb atom. In the third O site, O is bonded in a bent 150 degrees geometry to two equivalent W atoms. In the fourth O site, O is bonded in a 4-coordinate geometry to two equivalent Li and two equivalent Sb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaGa4Fe9C by Materials Project

LaFe9Ga4C crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. La is bonded in a distorted linear geometry to eight equivalent Fe, eight equivalent Ga, and two equivalent C atoms. All La–Fe bond lengths are 3.50 Å. All La–Ga bond lengths are 3.40 Å. Both La–C bond lengths are 2.90 Å. There are three inequivalent Fe sites. In the first Fe site, Fe is bonded to eight Fe and four equivalent Ga atoms to form FeGa4Fe8 cuboctahedra that share corners with four equivalent FeLa2Ga4Fe6 cuboctahedra, corners with four equivalent CLa2Fe4 octahedra, and faces with eight equivalent FeLa2Ga4Fe6 cuboctahedra. The corner-sharing octahedral tilt angles are 30°. There are four shorter (2.39 Å) and four longer (2.47 Å) Fe–Fe bond lengths. All Fe–Ga bond lengths are 2.59 Å. In the second Fe site, Fe is bonded in a single-bond geometry to three Fe, four equivalent Ga, and one C atom. Both Fe–Fe bond lengths are 2.54 Å. There are two shorter (2.55 Å) and two longer (2.66 Å) Fe–Ga bond lengths. The Fe–C bond length is 1.85 Å. In the third Fe site, Fe is bonded to two equivalent La, six Fe, and four equivalent Ga atoms to form distorted FeLa2Ga4Fe6 cuboctahedra that share corners with eight FeGa4Fe8 cuboctahedra, corners with two equivalent CLa2Fe4 octahedra, edges with four equivalent FeLa2Ga4Fe6 cuboctahedra, edges with two equivalent CLa2Fe4 octahedra, and faces with seven FeGa4Fe8 cuboctahedra. The corner-sharing octahedral tilt angles are 75°. There are two shorter (2.52 Å) and one longer (2.56 Å) Fe–Fe bond lengths. There are a spread of Fe–Ga bond distances ranging from 2.52–2.58 Å. Ga is bonded in a 12-coordinate geometry to two equivalent La, nine Fe, and one Ga atom. The Ga–Ga bond length is 2.84 Å. C is bonded to two equivalent La and four equivalent Fe atoms to form distorted CLa2Fe4 octahedra that share corners with twelve FeLa2Ga4Fe6 cuboctahedra, corners with two equivalent CLa2Fe4 octahedra, and edges with eight equivalent FeLa2Ga4Fe6 cuboctahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ErTiFe11C by Materials Project

ErTiFe11C crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Er is bonded in a distorted linear geometry to one Ti, ten Fe, and two equivalent C atoms. The Er–Ti bond length is 3.16 Å. There are a spread of Er–Fe bond distances ranging from 3.06–3.29 Å. Both Er–C bond lengths are 2.42 Å. Ti is bonded in a 1-coordinate geometry to one Er and thirteen Fe atoms. There are a spread of Ti–Fe bond distances ranging from 2.37–2.94 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are four shorter (2.46 Å) and two longer (2.64 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.89 Å. In the second Fe site, Fe is bonded in a single-bond geometry to two equivalent Ti, six Fe, and one C atom. There are four shorter (2.48 Å) and two longer (2.66 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.90 Å. In the third Fe site, Fe is bonded in a single-bond geometry to one Ti, six Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.69 Å. The Fe–C bond length is 1.88 Å. In the fourth Fe site, Fe is bonded to two equivalent Er, one Ti, and nine Fe atoms to form distorted FeEr2TiFe9 cuboctahedra that share corners with ten equivalent FeEr2TiFe9 cuboctahedra, corners with two equivalent CEr2Fe4 octahedra, edges with four equivalent FeEr2TiFe9 cuboctahedra, faces with six equivalent FeEr2TiFe9 cuboctahedra, and faces with two equivalent CEr2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 67–69°. There are a spread of Fe–Fe bond distances ranging from 2.42–2.63 Å. In the fifth Fe site, Fe is bonded in a 1-coordinate geometry to one Ti and eight Fe atoms. All Fe–Fe bond lengths are 2.97 Å. In the sixth Fe site, Fe is bonded in a 12-coordinate geometry to one Er, two equivalent Ti, and eleven Fe atoms. The Fe–Fe bond length is 2.43 Å. C is bonded to two equivalent Er and four Fe atoms to form CEr2Fe4 octahedra that share corners with eight equivalent FeEr2TiFe9 cuboctahedra, corners with two equivalent CEr2Fe4 octahedra, and faces with eight equivalent FeEr2TiFe9 cuboctahedra. The corner-sharing octahedral tilt angles are 2°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NdCr2Si2C by Materials Project

NdCr2Si2C crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Nd3+ is bonded in a distorted linear geometry to eight equivalent Si4- and two equivalent C4- atoms. All Nd–Si bond lengths are 3.09 Å. Both Nd–C bond lengths are 2.68 Å. Cr+4.50+ is bonded in a distorted linear geometry to four equivalent Si4- and two equivalent C4- atoms. All Cr–Si bond lengths are 2.45 Å. Both Cr–C bond lengths are 1.99 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Nd3+, four equivalent Cr+4.50+, and one Si4- atom. The Si–Si bond length is 2.50 Å. C4- is bonded to two equivalent Nd3+ and four equivalent Cr+4.50+ atoms to form corner-sharing CNd2Cr4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ni3Pb2SeS by Materials Project

Ni3Pb2SeS crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ni is bonded in a distorted linear geometry to four Pb, one Se, and one S atom. There are a spread of Ni–Pb bond distances ranging from 2.85–2.88 Å. The Ni–Se bond length is 2.31 Å. The Ni–S bond length is 2.16 Å. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded in a distorted hexagonal planar geometry to six equivalent Ni atoms. In the second Pb site, Pb is bonded to six equivalent Ni, one Se, and one S atom to form distorted corner-sharing PbNi6SeS hexagonal bipyramids. The Pb–Se bond length is 3.17 Å. The Pb–S bond length is 3.22 Å. Se is bonded in a 3-coordinate geometry to three equivalent Ni and one Pb atom. S is bonded in a 3-coordinate geometry to three equivalent Ni and one Pb atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TbTiFe11C by Materials Project

TbTiFe11C crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. Tb is bonded in a distorted linear geometry to one Ti, ten Fe, and two equivalent C atoms. The Tb–Ti bond length is 3.17 Å. There are a spread of Tb–Fe bond distances ranging from 3.07–3.30 Å. Both Tb–C bond lengths are 2.44 Å. Ti is bonded in a 1-coordinate geometry to one Tb and thirteen Fe atoms. There are a spread of Ti–Fe bond distances ranging from 2.36–2.95 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded in a single-bond geometry to six Fe and one C atom. There are four shorter (2.46 Å) and two longer (2.64 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.89 Å. In the second Fe site, Fe is bonded in a single-bond geometry to two equivalent Ti, six Fe, and one C atom. There are four shorter (2.48 Å) and two longer (2.65 Å) Fe–Fe bond lengths. The Fe–C bond length is 1.91 Å. In the third Fe site, Fe is bonded in a single-bond geometry to one Ti, six Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.71 Å. The Fe–C bond length is 1.89 Å. In the fourth Fe site, Fe is bonded to two equivalent Tb, one Ti, and nine Fe atoms to form distorted FeTb2TiFe9 cuboctahedra that share corners with ten equivalent FeTb2TiFe9 cuboctahedra, corners with two equivalent CTb2Fe4 octahedra, edges with four equivalent FeTb2TiFe9 cuboctahedra, faces with six equivalent FeTb2TiFe9 cuboctahedra, and faces with two equivalent CTb2Fe4 octahedra. The corner-sharing octahedra tilt angles range from 67–69°. There are a spread of Fe–Fe bond distances ranging from 2.43–2.63 Å. In the fifth Fe site, Fe is bonded in a 1-coordinate geometry to one Ti and eight Fe atoms. All Fe–Fe bond lengths are 2.98 Å. In the sixth Fe site, Fe is bonded in a 12-coordinate geometry to one Tb, two equivalent Ti, and eleven Fe atoms. The Fe–Fe bond length is 2.41 Å. C is bonded to two equivalent Tb and four Fe atoms to form CTb2Fe4 octahedra that share corners with eight equivalent FeTb2TiFe9 cuboctahedra, corners with two equivalent CTb2Fe4 octahedra, and faces with eight equivalent FeTb2TiFe9 cuboctahedra. The corner-sharing octahedral tilt angles are 2°.

36 MATERIALS SCIENCE↗
DOE OSTI2022

CEA Contribution to the PIP-II Linear Accelerator

The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and will deliver 10 low-beta cryomodules as In-Kind Contribution to the PIP-II project, with cavities supplied by LASA-INFN and power couplers and tuning systems supplied by Fermilab. This paper presents the CEA scope of work that includes the design, manufacturing, assembly and tests of the cryomodules and the upgrade of the existing infrastructures to the PIP-II requirements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2023

Final Design of the LB650 Cryomodule for the PIP-II Linear Accelerator

The Proton Improvement Plan II (PIP-II) that will be installed at Fermilab is the first U.S. accelerator project that will have significant contributions from international partners. CEA joined the international collaboration in 2018, and its scope covers the supply of the 650 MHz low-beta cryomodule section, with the design of the cryostat (i.e the cryomodule without the cavities, the power couplers and the frequency tuning systems) and the manufacturing of its components, the assembly and tests of the pre-production cryomodule and 9 production modules. An important milestone was reached in April 2023 with the Final Design Review. This paper presents the detailed design of the 650 MHz low-beta cryomodules.

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Parametric reduced-order modeling for component-oriented treatment and localized nonlinear feature inclusion

Abstract We propose coupling a physics-based reduction framework with a suited response decomposition technique to derive a component-oriented reduction (COR) approach, which is suitable for assembly systems featuring localized nonlinearities. Dependencies on influencing parameters are injected into the reduced-order model (ROM), thus ensuring robustness and validity over a domain of parametric inputs, while capturing nonlinear effects. The implemented approach employs individual component modes to capture localized features while additionally relying on reduced modes of a global nature to approximate the system’s dynamics accurately. The global modes are derived from a linear monolithic system, defined as a result of a coordinate separation scheme, which permits the proposed COR-ROM to naturally couple the response between linear and nonlinear subdomains. The derived low-order representation utilizes a proper orthogonal decomposition projection and is additionally reinforced with the inclusion of a hyper-reduction technique to capture the underlying high-fidelity model response while providing accelerated computations. The resulting approach is exemplified in the synthetic case studies of a four-story shear frame with multiple nonlinear regions driven by hysteresis and a large-scale kingpin connection featuring plasticity.

Vlachas, Konstantinos (ORCID:000000029124219X)↗
DOE OSTI2023

Parametric analysis on optimized design of hybrid solar power plants

There is increasing interest in utility-scale solar power plants with storage which can flexibly dispatch renewable energy to the grid. However, plant design possesses many degrees of freedom and non-obvious trade-offs in performance. Software tools can estimate or optimize the performance of a specific plant configuration under market and weather conditions of interest; the associated cost parameters and operating assumptions strongly influence estimates of plant performance and decisions regarding optimal sizing. We employ the National Renewable Energy Laboratory's Hybrid Optimization and Performance Platform, which incorporates optimal dispatch when evaluating plant performance, and investigate the sensitivity to weather and market conditions, operating limitations, and the presence of a capacity-based incentive. We demonstrate changes in plant performance and optimal sizing with respect to these inputs and discuss implications. Here results show that PV-with-battery designs are more profitable under our assumptions, but that designs including a concentrated solar power (CSP) system produce significantly greater annual energy; and that CSP-with-thermal energy storage designs maximizing the benefit-to-cost ratio have an input-dependent linear relationship between the CSP field solar multiple and the hours of storage as the project budget varies.

14 SOLAR ENERGY↗
DOE OSTI2022

Generation and Control of Self-Organized Nonlinear Kinetic Structures in High Energy Density Plasmas in the Presence of Intense Magnetic Fields and Ultrashort Laser Pulses

In the project we investigated mechanisms to sculpt phase space by controlling plasma instabilities. We found that linear theory, which applies in the initial growth phase of an instability, allows for initial conditions that can suppress instabilities. This provides a possible mechanism to release the energy available to an instability on demand. We developed various computational techniques that can reduce computational cost of simulations while maintaining or improving physical fidelity. We considered the Buneman instability in the presence of a ponderomotively driven plasma wave to examine the interplay between an instability and steady-state plasma response.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Measurement of Volatile Compounds for Real-Time Analysis of Soil Microbial Metabolic Response to Simulated Snowmelt

Snowmelt dynamics are a significant determinant of microbial metabolism in soil and regulate global biogeochemical cycles of carbon and nutrients by creating seasonal variations in soil redox and nutrient pools. With an increasing concern that climate change accelerates both snowmelt timing and rate, obtaining an accurate characterization of microbial response to snowmelt is important for understanding biogeochemical cycles intertwined with soil. However, observing microbial metabolism and its dynamics non-destructively remains a major challenge for systems such as soil. Microbial volatile compounds (mVCs) emitted from soil represent information-dense signatures and when assayed non-destructively using state-of-the-art instrumentation such as Proton Transfer Reaction-Time of Flight-Mass Spectrometry (PTR-TOF-MS) provide time resolved insights into the metabolism of active microbiomes. In this study, we used PTR-TOF-MS to investigate the metabolic trajectory of microbiomes from a subalpine forest soil, and their response to a simulated wet-up event akin to snowmelt. Using an information theory approach based on the partitioning of mutual information, we identified mVC metabolite pairs with robust interactions, including those that were non-linear and with time lags. The biological context for these mVC interactions was evaluated by projecting the connections onto the Kyoto Encyclopedia of Genes and Genomes (KEGG) network of known metabolic pathways. Simulated snowmelt resulted in a rapid increase in the production of trimethylamine (TMA) suggesting that anaerobic degradation of quaternary amine osmo/cryoprotectants, such as glycine betaine, may be important contributors to this resource pulse. Unique and synergistic connections between intermediates of methylotrophic pathways such as dimethylamine, formaldehyde and methanol were observed upon wet-up and indicate that the initial pulse of TMA was likely transformed into these intermediates by methylotrophs. Increases in ammonia oxidation signatures (transformation of hydroxylamine to nitrite) were observed in parallel, and while the relative role of nitrifiers or methylotrophs cannot be confirmed, the inferred connection to TMA oxidation suggests either a direct or indirect coupling between these processes. Overall, it appears that such mVC time-series from PTR-TOF-MS combined with causal inference represents an attractive approach to non-destructively observe soil microbial metabolism and its response to environmental perturbation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Dimensional Reduction for Sampled Priors and Application to Photometric Redshift Distributions

A typical Bayesian inference on the values of some parameters of interest q from some data D involves running a Markov Chain (MC) to sample from the posterior $p$($q$,$n$|$D$) $\propto$ $\mathcal{L}$($D$|$q$,$n$)$p$(q)$p$($n$), where n are some nuisance parameters with a separable prior. In some cases, the nuisance parameters are high-dimensional, and their prior p(n) is itself defined only by a set of samples that have been drawn from some other MC. The MC for the posterior will typically require evaluation of p(n) at arbitrary values of n, i.e., one needs to provide a density estimator over the full n space from the provided samples. But the high dimensionality of n hinders both the density estimation and the efficiency of the MC for the posterior. We describe a solution to this problem: a linear compression of the n space into a much lower-dimensional space u, which projects away directions in n space that cannot appreciably alter $\mathcal{L}$. The algorithm for doing so is a slight modification to principal components analysis, and is less restrictive on p(n) than other proposed solutions to this issue. We demonstrate this “mode projection” technique using the analysis of 2-point correlation functions of weak lensing fields and galaxy density in the Dark Energy Survey, where n is a binned representation of the redshift distribution n(z) of the galaxies.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2022

Gauge invariants of linearized gravity with a general background metric

In linearized gravity with distributed matter, the background metric has no generic symmetries, and decomposition of the metric perturbation into global normal modes is generally impractical. This complicates the identification of the gauge-invariant part of the perturbation, which is a concern, for example, in the theory of dispersive gravitational waves (GWs) whose energy–momentum must be gauge-invariant. Here, we propose how to identify the gauge-invariant part of the metric perturbation and the six independent gauge invariants per se for an arbitrary background metric. For the Minkowski background, the operator that projects the metric perturbation on the invariant subspace is proportional to the well-known dispersion operator of linear GWs in vacuum. For a general background, this operator is expressed in terms of the Green’s operator of the vacuum wave equation. Further, if the background is smooth, it can be found asymptotically using the inverse scale of the background metric as a small parameter.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2020

Materials Data on InCuO2 by Materials Project

CuInO2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cu1+ is bonded in a linear geometry to two equivalent O2- atoms. Both Cu–O bond lengths are 1.85 Å. In3+ is bonded to six equivalent O2- atoms to form edge-sharing InO6 octahedra. All In–O bond lengths are 2.21 Å. O2- is bonded to one Cu1+ and three equivalent In3+ atoms to form a mixture of distorted edge and corner-sharing OIn3Cu tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on InAgO2 by Materials Project

AgInO2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ag1+ is bonded in a linear geometry to two equivalent O2- atoms. Both Ag–O bond lengths are 2.11 Å. In3+ is bonded to six equivalent O2- atoms to form edge-sharing InO6 octahedra. All In–O bond lengths are 2.21 Å. O2- is bonded to one Ag1+ and three equivalent In3+ atoms to form a mixture of distorted corner and edge-sharing OIn3Ag tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgC2 by Materials Project

MgC2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Mg2+ is bonded in a distorted linear geometry to six equivalent C1- atoms. There are two shorter (2.17 Å) and four longer (2.57 Å) Mg–C bond lengths. C1- is bonded in a 2-coordinate geometry to three equivalent Mg2+ and one C1- atom. The C–C bond length is 1.26 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ag2HgO2 by Materials Project

Ag2HgO2 crystallizes in the tetragonal P4_32_12 space group. The structure is three-dimensional. Ag1+ is bonded in a linear geometry to two equivalent O2- atoms. There are one shorter (2.13 Å) and one longer (2.14 Å) Ag–O bond lengths. Hg2+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent O2- atoms. There are two shorter (2.09 Å) and two longer (2.62 Å) Hg–O bond lengths. O2- is bonded to two equivalent Ag1+ and two equivalent Hg2+ atoms to form corner-sharing OAg2Hg2 tetrahedra.

36 MATERIALS SCIENCE↗