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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on NaYbF4 by Materials Project

NaYbF4 is alpha bismuth trifluoride-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Na1+ is bonded in a body-centered cubic geometry to eight F1- atoms. There are five shorter (2.40 Å) and three longer (2.41 Å) Na–F bond lengths. Yb3+ is bonded in a body-centered cubic geometry to eight F1- atoms. There are six shorter (2.31 Å) and two longer (2.32 Å) Yb–F bond lengths. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded to two equivalent Na1+ and two equivalent Yb3+ atoms to form a mixture of edge and corner-sharing FNa2Yb2 tetrahedra. In the second F1- site, F1- is bonded to two equivalent Na1+ and two equivalent Yb3+ atoms to form a mixture of edge and corner-sharing FNa2Yb2 tetrahedra. In the third F1- site, F1- is bonded to two equivalent Na1+ and two equivalent Yb3+ atoms to form a mixture of edge and corner-sharing FNa2Yb2 tetrahedra. In the fourth F1- site, F1- is bonded to two equivalent Na1+ and two equivalent Yb3+ atoms to form a mixture of edge and corner-sharing FNa2Yb2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Fast inversion, preconditioned quantum linear system solvers, fast Green's-function computation, and fast evaluation of matrix functions

Preconditioning is the most widely used and effective way for treating ill-conditioned linear systems in the context of classical iterative linear system solvers. We introduce a quantum primitive called fast inversion, which can be used as a preconditioner for solving quantum linear systems. The key idea of fast inversion is to directly block encode a matrix inverse through a quantum circuit implementing the inversion of eigenvalues via classical arithmetics. We demonstrate the application of preconditioned linear system solvers for computing single-particle Green's functions of quantum many-body systems, which are widely used in quantum physics, chemistry, and materials science. We analyze the complexities in three scenarios: the Hubbard model, the quantum many-body Hamiltonian in the plane-wave-dual basis, and the Schwinger model. We also provide a method for performing Green's function calculation in second quantization within a fixed-particle manifold and note that this approach may be valuable for simulation more broadly. Aside from solving linear systems, fast inversion also allows us to develop fast algorithms for computing matrix functions, such as the efficient preparation of Gibbs states. Furthermore, we introduce two efficient approaches for such a task, based on the contour-integral formulation and the inverse transform, respectively.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2025

Deep learning of structural morphology imaged by scanning X-ray diffraction microscopy

Scanning X-ray nanodiffraction microscopy is a powerful technique for spatially resolving nanoscale structural morphologies by diffraction contrast. One of the critical challenges in experimental nanodiffraction data analysis is posed by the convergence angle of nanoscale focusing optics which creates simultaneous dependency of the far-field scattering data on three independent components of the local strain tensor-corresponding to dilation and two potential rigid body rotations of the unit cell. All three components are in principle resolvable through a spatially mapped sample tilt series; however, traditional data analysis is computationally expensive and prone to artifacts. In this study, we implement NanobeamNN, a convolutional neural network specifically tailored to the analysis of scanning probe X-ray microscopy data. NanobeamNN learns lattice strain and rotation angles from simulated diffraction of a focused X-ray nanobeam by an epitaxial thin film and can directly make reasonable predictions on experimental data without the need for additional fine-tuning. We demonstrate that this approach represents a significant advancement in computational speed over conventional methods, as well as a potential improvement in accuracy over the current standard.

Luo, Aileen [Cornell Univ., Ithaca, NY (United Sta↗
DOE OSTI2020

Materials Data on VZnRh2 by Materials Project

VRh2Zn is Heusler structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. V is bonded in a body-centered cubic geometry to eight equivalent Rh atoms. There are six shorter (2.62 Å) and two longer (2.63 Å) V–Rh bond lengths. Rh is bonded in a body-centered cubic geometry to four equivalent V and four equivalent Zn atoms. There are three shorter (2.62 Å) and one longer (2.63 Å) Rh–Zn bond lengths. Zn is bonded in a body-centered cubic geometry to eight equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on VGeRu2 by Materials Project

Ru2VGe is Heusler structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. V is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. There are six shorter (2.62 Å) and two longer (2.63 Å) V–Ru bond lengths. Ru is bonded in a body-centered cubic geometry to four equivalent V and four equivalent Ge atoms. There are three shorter (2.62 Å) and one longer (2.63 Å) Ru–Ge bond lengths. Ge is bonded in a distorted body-centered cubic geometry to eight equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdCdHg2 by Materials Project

GdHg2Cd is Heusler structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Gd is bonded in a body-centered cubic geometry to eight equivalent Hg atoms. There are six shorter (3.15 Å) and two longer (3.16 Å) Gd–Hg bond lengths. Hg is bonded in a body-centered cubic geometry to four equivalent Gd and four equivalent Cd atoms. There are three shorter (3.15 Å) and one longer (3.16 Å) Hg–Cd bond lengths. Cd is bonded in a distorted body-centered cubic geometry to eight equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaSnRu2 by Materials Project

TaRu2Sn is Heusler structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ta is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. There are six shorter (2.76 Å) and two longer (2.77 Å) Ta–Ru bond lengths. Ru is bonded in a body-centered cubic geometry to four equivalent Ta and four equivalent Sn atoms. There are three shorter (2.76 Å) and one longer (2.77 Å) Ru–Sn bond lengths. Sn is bonded in a distorted body-centered cubic geometry to eight equivalent Ru atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg7GaAg12 by Materials Project

Mg7Ag12Ga crystallizes in the trigonal R3m space group. The structure is three-dimensional. there are seven inequivalent Mg sites. In the first Mg site, Mg is bonded in a body-centered cubic geometry to eight Ag atoms. All Mg–Ag bond lengths are 2.87 Å. In the second Mg site, Mg is bonded in a distorted body-centered cubic geometry to fourteen Ag atoms. There are a spread of Mg–Ag bond distances ranging from 2.87–3.31 Å. In the third Mg site, Mg is bonded in a distorted body-centered cubic geometry to eleven Ag atoms. There are a spread of Mg–Ag bond distances ranging from 2.86–3.31 Å. In the fourth Mg site, Mg is bonded in a body-centered cubic geometry to eight Ag atoms. All Mg–Ag bond lengths are 2.87 Å. In the fifth Mg site, Mg is bonded in a distorted body-centered cubic geometry to eleven Ag atoms. There are a spread of Mg–Ag bond distances ranging from 2.86–3.30 Å. In the sixth Mg site, Mg is bonded in a body-centered cubic geometry to eight Ag atoms. There are one shorter (2.86 Å) and seven longer (2.87 Å) Mg–Ag bond lengths. In the seventh Mg site, Mg is bonded in a body-centered cubic geometry to eight Ag atoms. There are seven shorter (2.87 Å) and one longer (2.88 Å) Mg–Ag bond lengths. There are thirteen inequivalent Ag sites. In the first Ag site, Ag is bonded in a body-centered cubic geometry to eight Mg atoms. In the second Ag site, Ag is bonded to four Mg and four Ag atoms to form a mixture of distorted edge, corner, and face-sharing AgMg4Ag4 tetrahedra. All Ag–Ag bond lengths are 2.87 Å. In the third Ag site, Ag is bonded in a 8-coordinate geometry to seven Mg and one Ag atom. The Ag–Ag bond length is 2.87 Å. In the fourth Ag site, Ag is bonded in a body-centered cubic geometry to five Mg and three equivalent Ga atoms. All Ag–Ga bond lengths are 2.87 Å. In the fifth Ag site, Ag is bonded in a 8-coordinate geometry to four Mg, three equivalent Ag, and one Ga atom. All Ag–Ag bond lengths are 2.87 Å. The Ag–Ga bond length is 2.86 Å. In the sixth Ag site, Ag is bonded in a body-centered cubic geometry to seven Mg and one Ga atom. The Ag–Ga bond length is 2.87 Å. In the seventh Ag site, Ag is bonded in a 8-coordinate geometry to five Mg and three equivalent Ag atoms. All Ag–Ag bond lengths are 2.87 Å. In the eighth Ag site, Ag is bonded in a body-centered cubic geometry to eight Mg atoms. In the ninth Ag site, Ag is bonded in a 8-coordinate geometry to four Mg, one Ag, and three equivalent Ga atoms. The Ag–Ag bond length is 2.88 Å. All Ag–Ga bond lengths are 2.87 Å. In the tenth Ag site, Ag is bonded to four Mg and four Ag atoms to form a mixture of distorted edge, corner, and face-sharing AgMg4Ag4 tetrahedra. All Ag–Ag bond lengths are 2.87 Å. In the eleventh Ag site, Ag is bonded in a 8-coordinate geometry to six Mg and eight Ag atoms. In the twelfth Ag site, Ag is bonded in a 8-coordinate geometry to six Mg and eight Ag atoms. In the thirteenth Ag site, Ag is bonded in a 8-coordinate geometry to six Mg and eight Ag atoms. There are three shorter (3.30 Å) and three longer (3.31 Å) Ag–Mg bond lengths. There are seven shorter (2.87 Å) and one longer (2.88 Å) Ag–Ag bond lengths. Ga is bonded in a distorted body-centered cubic geometry to eight Ag atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Mechanism of drying-induced change in the physical properties of concrete: A mesoscale simulation study

Although many studies have found that drying alters the mechanical properties of concrete, the mechanism behind this change remains unclarified. The aim of this study is to elucidate the mechanism of change in properties of concrete after drying through the numerical calculation: a 3D mesoscale rigid-body-spring model (RBSM) with three phases, i.e. mortar, aggregate, and the interfacial transition zone while considering the properties changes of mortar due to drying. Based on the RBSM results, it is concluded that the change in compressive strength due to drying and heating is determined by a balance of the impact of drying-induced microcracking around coarse aggregates and the change in mechanical properties of the mortar due to drying. These mechanisms change the applied load required to reach the critical crack width and distribution, at which rim of the specimen begins to isolate from the core region and the load sustained by the rim decreases.

36 MATERIALS SCIENCE↗
DOE OSTI2021

On the influence of test speed and environment in the fatigue life of small diameter nitinol and stainless steel wire

Here, to better understand the complex interplay of speed and environment on metals commonly used in implants, rotary bend fatigue tests were conducted on stainless steel and nitinol wires. A range of alternating strains was tested to create ε-N curves at two speeds (physiologic and accelerated) and in three environments (deionized water at body temperature, phosphate buffered saline at body temperature, and laboratory air at ambient room temperature). Results indicate that speed and environment can affect the observed fatigue life in nuanced ways. An electropotential monitoring technique was demonstrated to characterize fatigue crack growth which may be useful in future investigations.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Energy spectrum of two-particle scattering in a periodic box

We aim to compute the discrete energy spectrum for two-body scattering in a three-dimensional box under periodic boundary conditions. The spectrum in the center of mass is obtained by solving the Schödinger equation in a test potential using the Fourier basis. The focus is on how to project the spectrum into the various irreducible representations of the symmetry groups of the box. Four examples are given to show how the infinite-volume spectrum (including both bound and scattering states) is resolved in cubic or elongated boxes, and in systems with integer or half-integer total spin. Such a demonstration is a crucial step in relating the discrete spectrum in the box to the infinite-volume scattering phaseshifts via the Lüscher method.

Computer Science↗
DOE OSTI2024

Experimental investigation of heat treatments on the mechanical performance of grade 300 maraging steel strut-based lattices

Lightweight and strong components are essential for reducing energy consumption and enhancing efficiency. Lattice structures are one such geometry utilized to achieve weight reduction. This study investigates the mechanical properties of various lattice structures fabricated from Maraging Steel (EOS MS1) using the Direct Metal Laser Sintering (DMLS) method. The samples include three distinct cellular geometries: body-centered cubic (BCC), face-centered cubic (FCC), and octet truss configurations, which are subjected to tensile and compressive tests. The primary goal of this research is to evaluate the impact of heat treatment on the mechanical properties of cellular architecture under tensile and compressive loading conditions. Destructive, nondestructive testing, and simulation results were also obtained from different heat treatment processes. It was found that the age-hardened specimens performed the best overall in terms of ultimate tensile/compressive strength and elongation. The top-performing topologies in compression and tension were found to be the octet structure, as they were able to withstand the most loading and straining when compared to the other specimens.

Engineering↗
DOE OSTI2021

Automating Discovery of Physics-Informed Neural State Space Models via Learning and Evolution

Recent works exploring deep learning application to dynamical systems modeling have demonstrated that embedding physical priors into neural networks can yield more effective, physically-realistic, and data-efficient models. However, in the absence of complete prior knowledge of a dynamical system's physical characteristics, determining the optimal structure and optimization strategy for these models can be difficult. In this work, we explore methods for discovering neural state space dynamics models for system identification. Starting with a design space of block-oriented state space models and structured linear maps with strong physical priors, we encode these components into a model genome alongside network structure, penalty constraints, and optimization hyperparameters. Demonstrating the overall utility of the design space, we employ an asynchronous genetic search algorithm that alternates between model selection and optimization and obtains accurate physically consistent models of three physical systems: an aerodynamics body, a continuous stirred tank reactor, and a two tank interacting system.

genetic algorithms, neural architecture search, ne↗
DOE OSTI2020

Materials Data on U5As3Se2 by Materials Project

U5As3Se2 is Heusler-like structured and crystallizes in the tetragonal I4/m space group. The structure is three-dimensional. there are two inequivalent U sites. In the first U site, U is bonded in a body-centered cubic geometry to five As and three equivalent Se atoms. There are a spread of U–As bond distances ranging from 3.03–3.06 Å. All U–Se bond lengths are 3.05 Å. In the second U site, U is bonded in a body-centered cubic geometry to four equivalent As and four equivalent Se atoms. All U–As bond lengths are 3.05 Å. All U–Se bond lengths are 3.05 Å. There are three inequivalent As sites. In the first As site, As is bonded in a body-centered cubic geometry to eight U atoms. In the second As site, As is bonded in a body-centered cubic geometry to eight equivalent U atoms. In the third As site, As is bonded in a body-centered cubic geometry to eight equivalent U atoms. Se is bonded in a body-centered cubic geometry to eight U atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba4Ga22Sn by Materials Project

Ba4Ga22Sn crystallizes in the cubic I-43m space group. The structure is three-dimensional. Ba is bonded in a 1-coordinate geometry to thirteen Ga and one Sn atom. There are a spread of Ba–Ga bond distances ranging from 3.29–3.72 Å. The Ba–Sn bond length is 3.61 Å. There are three inequivalent Ga sites. In the first Ga site, Ga is bonded in a distorted body-centered cubic geometry to four equivalent Ba, three equivalent Ga, and one Sn atom. All Ga–Ga bond lengths are 2.57 Å. The Ga–Sn bond length is 2.69 Å. In the second Ga site, Ga is bonded in a 4-coordinate geometry to four equivalent Ga atoms. All Ga–Ga bond lengths are 2.60 Å. In the third Ga site, Ga is bonded in a 7-coordinate geometry to three equivalent Ba and four Ga atoms. The Ga–Ga bond length is 2.57 Å. Sn is bonded in a body-centered cubic geometry to four equivalent Ba and four equivalent Ga atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th4UTe5 by Materials Project

UTh4Te5 is Heusler-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. U is bonded in a body-centered cubic geometry to eight equivalent Te atoms. All U–Te bond lengths are 3.31 Å. There are two inequivalent Th sites. In the first Th site, Th is bonded in a body-centered cubic geometry to eight Te atoms. There are four shorter (3.32 Å) and four longer (3.33 Å) Th–Te bond lengths. In the second Th site, Th is bonded in a body-centered cubic geometry to eight Te atoms. All Th–Te bond lengths are 3.32 Å. There are three inequivalent Te sites. In the first Te site, Te is bonded in a body-centered cubic geometry to four equivalent U and four equivalent Th atoms. In the second Te site, Te is bonded in a body-centered cubic geometry to eight Th atoms. In the third Te site, Te is bonded in a body-centered cubic geometry to eight equivalent Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti8Co3NiSn4 by Materials Project

Ti8Co3NiSn4 is Heusler-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are six inequivalent Ti sites. In the first Ti site, Ti is bonded in a body-centered cubic geometry to four Co and four Sn atoms. All Ti–Co bond lengths are 2.78 Å. There are three shorter (2.78 Å) and one longer (2.79 Å) Ti–Sn bond lengths. In the second Ti site, Ti is bonded in a body-centered cubic geometry to four Co and four equivalent Sn atoms. All Ti–Co bond lengths are 2.78 Å. All Ti–Sn bond lengths are 2.78 Å. In the third Ti site, Ti is bonded in a body-centered cubic geometry to three equivalent Co, one Ni, and four Sn atoms. All Ti–Co bond lengths are 2.78 Å. The Ti–Ni bond length is 2.79 Å. All Ti–Sn bond lengths are 2.78 Å. In the fourth Ti site, Ti is bonded in a body-centered cubic geometry to one Co, three equivalent Ni, and four equivalent Sn atoms. The Ti–Co bond length is 2.78 Å. All Ti–Ni bond lengths are 2.78 Å. All Ti–Sn bond lengths are 2.78 Å. In the fifth Ti site, Ti is bonded in a body-centered cubic geometry to one Co, three equivalent Ni, and four equivalent Sn atoms. The Ti–Co bond length is 2.78 Å. All Ti–Ni bond lengths are 2.78 Å. All Ti–Sn bond lengths are 2.78 Å. In the sixth Ti site, Ti is bonded in a body-centered cubic geometry to one Co, three equivalent Ni, and four equivalent Sn atoms. The Ti–Co bond length is 2.78 Å. All Ti–Ni bond lengths are 2.78 Å. All Ti–Sn bond lengths are 2.78 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded in a body-centered cubic geometry to eight Ti atoms. In the second Co site, Co is bonded in a body-centered cubic geometry to eight Ti atoms. Ni is bonded in a body-centered cubic geometry to eight Ti atoms. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a body-centered cubic geometry to eight Ti atoms. In the second Sn site, Sn is bonded in a body-centered cubic geometry to eight Ti atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

An invertible seven-dimensional Dirichlet cell characterization of lattices

Characterization of crystallographic lattices is an important tool in structure solution, crystallographic database searches and clustering of diffraction images in serial crystallography. Characterization of lattices by Niggli-reduced cells (based on the three shortest non-coplanar lattice vectors) or by Delaunay-reduced cells (based on four non-coplanar vectors summing to zero and all meeting at obtuse or right angles) is commonly performed. The Niggli cell derives from Minkowski reduction. The Delaunay cell derives from Selling reduction. All are related to the Wigner–Seitz (or Dirichlet, or Voronoi) cell of the lattice, which consists of the points at least as close to a chosen lattice point as they are to any other lattice point. The three non-coplanar lattice vectors chosen are here called the Niggli-reduced cell edges. Starting from a Niggli-reduced cell, the Dirichlet cell is characterized by the planes determined by 13 lattice half-edges: the midpoints of the three Niggli cell edges, the six Niggli cell face-diagonals and the four body-diagonals, but seven of the lengths are sufficient: three edge lengths, the three shorter of each pair of face-diagonal lengths, and the shortest body-diagonal length. These seven are sufficient to recover the Niggli-reduced cell.

Chemistry↗