Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “linear projection”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on FeCuAs2PbO10 by Materials Project

FeCuPbAs2O10 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Fe3+ is bonded in a distorted linear geometry to two equivalent O2- atoms. Both Fe–O bond lengths are 1.59 Å. Cu3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cu–O bond distances ranging from 1.84–2.41 Å. Pb4+ is bonded in a distorted linear geometry to four O2- atoms. There are two shorter (2.02 Å) and two longer (2.69 Å) Pb–O bond lengths. As5+ is bonded in a 1-coordinate geometry to four O2- atoms. There are a spread of As–O bond distances ranging from 1.45–2.22 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Fe3+ and one Cu3+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Cu3+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one As5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Cu3+, one Pb4+, and one As5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Pb4+ and one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgU2(SiO9)2 by Materials Project

MgU2(SiO9)2 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Mg is bonded in a linear geometry to six O atoms. There are two shorter (1.83 Å) and four longer (2.73 Å) Mg–O bond lengths. U is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of U–O bond distances ranging from 1.82–2.54 Å. Si is bonded in a tetrahedral geometry to four O atoms. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. There are seven inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one U atom. In the second O site, O is bonded in a single-bond geometry to one U atom. In the third O site, O is bonded in a bent 150 degrees geometry to one U and one Si atom. In the fourth O site, O is bonded in a linear geometry to one Mg and one Si atom. In the fifth O site, O is bonded in a 1-coordinate geometry to two equivalent U and one Si atom. In the sixth O site, O is bonded in a bent 150 degrees geometry to one Mg and one O atom. The O–O bond length is 1.29 Å. In the seventh O site, O is bonded in a bent 120 degrees geometry to two equivalent O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaPtO2 by Materials Project

PtGaO2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pt2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Pt–O bond lengths are 2.06 Å. Ga2+ is bonded to six equivalent O2- atoms to form edge-sharing GaO6 octahedra. All Ga–O bond lengths are 1.99 Å. O2- is bonded to one Pt2+ and three equivalent Ga2+ atoms to form a mixture of distorted edge and corner-sharing OGa3Pt trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on As2S by Materials Project

As2S crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. As1+ is bonded in a linear geometry to two equivalent S2- atoms. Both As–S bond lengths are 2.56 Å. S2- is bonded in a 4-coordinate geometry to four equivalent As1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li(Mo3S4)2 by Materials Project

Li1Mo6S8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Li1+ is bonded in a distorted linear geometry to eight S2- atoms. There are two shorter (2.41 Å) and six longer (3.22 Å) Li–S bond lengths. Mo+2.50+ is bonded to five S2- atoms to form a mixture of corner and edge-sharing MoS5 square pyramids. There are a spread of Mo–S bond distances ranging from 2.44–2.48 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to one Li1+ and three equivalent Mo+2.50+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to one Li1+ and four equivalent Mo+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(AgO)2 by Materials Project

Cu(AgO)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ag1+ is bonded in a linear geometry to two O2- atoms. There are one shorter (2.13 Å) and one longer (2.14 Å) Ag–O bond lengths. Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.02 Å) and two longer (2.03 Å) Cu–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a square co-planar geometry to two equivalent Ag1+ and two equivalent Cu2+ atoms. In the second O2- site, O2- is bonded in a square co-planar geometry to two equivalent Ag1+ and two equivalent Cu2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NiPtO2 by Materials Project

PtNiO2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pt2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Pt–O bond lengths are 1.96 Å. Ni2+ is bonded to six equivalent O2- atoms to form edge-sharing NiO6 octahedra. All Ni–O bond lengths are 2.00 Å. O2- is bonded to one Pt2+ and three equivalent Ni2+ atoms to form a mixture of distorted edge and corner-sharing ONi3Pt trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sb2Te by Materials Project

Sb2Te crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. Sb1+ is bonded in a linear geometry to two equivalent Te2- atoms. Both Sb–Te bond lengths are 3.04 Å. Te2- is bonded in a 4-coordinate geometry to four equivalent Sb1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on P2S by Materials Project

SP2 crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. P1+ is bonded in a linear geometry to two equivalent S2- atoms. Both P–S bond lengths are 2.39 Å. S2- is bonded in a 4-coordinate geometry to four equivalent P1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on P2Se by Materials Project

PPSe crystallizes in the tetragonal I-42d space group. The structure is three-dimensional. P1+ is bonded in a linear geometry to two equivalent Se2- atoms. Both P–Se bond lengths are 2.52 Å. Se2- is bonded in a 4-coordinate geometry to four equivalent P1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ni3(PbS)2 by Materials Project

Ni3Pb2S2 crystallizes in the cubic I2_13 space group. The structure is three-dimensional. Ni is bonded in a distorted linear geometry to four equivalent Pb and two equivalent S atoms. There are two shorter (2.85 Å) and two longer (2.91 Å) Ni–Pb bond lengths. Both Ni–S bond lengths are 2.16 Å. Pb is bonded in a 7-coordinate geometry to six equivalent Ni and one S atom. The Pb–S bond length is 3.17 Å. S is bonded in a 3-coordinate geometry to three equivalent Ni and one Pb atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GaAgO2 by Materials Project

AgGaO2 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 2.13 Å. Ga3+ is bonded to six equivalent O2- atoms to form edge-sharing GaO6 octahedra. All Ga–O bond lengths are 2.02 Å. O2- is bonded to one Ag1+ and three equivalent Ga3+ atoms to form a mixture of distorted corner and edge-sharing OGa3Ag tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Kinematics reconstruction in solenoidal spectrometers operated in active target mode

Here, we discuss the reconstruction of low-energy nuclear reaction kinematics from charged-particle tracks in solenoidal spectrometers working in Active Target Time Projection Chamber mode. In this operation mode, reaction products are tracked within the active gas medium of the Active Target with a three dimensional space point cloud. We have inferred the reaction kinematics from the point cloud using an algorithm based on a linear quadratic estimator (Kalman filter). The performance of this algorithm has been evaluated using experimental data from nuclear reactions measured with the Active Target Time Projection Chamber (AT-TPC) detector.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Observation of Weyl fermions in a magnetic non-centrosymmetric crystal

The absence of inversion symmetry in non-centrosymmetric materials has a fundamental role in the emergence of a vast number of fascinating phenomena, like ferroelectricity, second harmonic generation, and Weyl fermions. The removal of time-reversal symmetry in such systems further extends the variety of observable magneto-electric and topological effects. Here we report the striking topological properties in the non-centrosymmetric spin-orbit magnet PrAlGe by combining spectroscopy and transport measurements. By photoemission spectroscopy below the Curie temperature, we observe topological Fermi arcs that correspond to projected topological charges of ±1 in the surface Brillouin zone. In the bulk, we observe the linear energy-dispersion of the Weyl fermions. We further observe a large anomalous Hall response in our magneto-transport measurements, which is understood to arise from diverging bulk Berry curvature fields associated with the Weyl band structure. These results establish a novel Weyl semimetal phase in magnetic non-centrosymmetric PrAlGe.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Δ$\textit{K}=0 \textit{M}1$ Excitation Strength of the Well-Deformed Nucleus 164 Dy from $\textit{K}$ Mixing

We report the size of a Δ$\textit{K}=0 \textit{M}1$ excitation strength has been determined for the first time in a predominantly axially deformed even-even nucleus. It has been obtained from the observation of a rare $\textit{K}$-mixing situation between two close-lying $J^π = 1^+$ states of the nucleus 164 Dy with components characterized by intrinsic projection quantum numbers $\textit{K}$ = 0 and $\textit{K}$ = 1. Nuclear resonance fluorescence induced by quasimonochromatic linearly polarized γ-ray beams provided evidence for $\textit{K}$ mixing of the 1 + states at 3159.1(3) and 3173.6(3) keV in excitation energy from their γ-decay branching ratios into the ground-state band. The Δ$\textit{K}$ = 0 transition strength of $B(M1; 0^+_1 → 1^+_{K=0}) = 0.008(1)μ^2_N$ was inferred from a mixing analysis of their $\textit{M}$1 transition rates into the ground-state band. It is in agreement with predictions from the quasiparticle phonon nuclear model. This determination represents first experimental information on the $\textit{M}$1 excitation strength of a nuclear quantum state with a negative $\mathcal{R}$-symmetry quantum number.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2023

Mapping nanocrystal orientations via scanning Laue diffraction microscopy for multi-peak Bragg coherent diffraction imaging

The recent commissioning of a movable monochromator at the 34-ID-C endstation of the Advanced Photon Source has vastly simplified the collection of Bragg coherent diffraction imaging (BCDI) data from multiple Bragg peaks of sub-micrometre scale samples. Laue patterns arising from the scattering of a polychromatic beam by arbitrarily oriented nanocrystals permit their crystal orientations to be computed, which are then used for locating and collecting several non-co-linear Bragg reflections. The volumetric six-component strain tensor is then constructed by combining the projected displacement fields that are imaged using each of the measured reflections via iterative phase retrieval algorithms. Complications arise when the sample is heterogeneous in composition and/or when multiple grains of a given lattice structure are simultaneously illuminated by the polychromatic beam. Here, a workflow is established for orienting and mapping nanocrystals on a substrate of a different material using scanning Laue diffraction microscopy. The capabilities of the developed algorithms and procedures with both synthetic and experimental data are demonstrated. The robustness is verified by comparing experimental texture maps obtained with Laue diffraction microscopy at the beamline with maps obtained from electron back-scattering diffraction measurements on the same patch of gold nanocrystals. Such tools provide reliable indexing for both isolated and densely distributed nanocrystals, which are challenging to image in three dimensions with other techniques.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Efficient Image Reconstruction Method for a Millimeter-wave Shoe Scanner

The Pacific Northwest National Laboratory (PNNL) has recently developed an active 3D microwave/millimeter-wave shoe scanner. This system is designed to detect threats concealed within the soles of common footwear. The system operates over the 10-40 GHz frequency range for excellent penetration of common materials. The system presents several challenges for efficient image reconstruction, including the thick dielectric window, multi-row linear arrays, and focusing close to the antenna elements. In this paper, an efficient back-projection reconstruction algorithm is presented that overcomes these challenges. Experimental imaging results are shown that demonstrate high-resolution imaging performance for this new scanner.

Sheen, David M.↗
DOE OSTI2024

Convergence of Weak-SINDy Surrogate Models

In this paper, we give an in-depth error analysis for surrogate models generated by a variant of the Sparse Identification of Nonlinear Dynamics (SINDy) method. We start with an overview of a variety of nonlinear system identification techniques, namely SINDy, weak-SINDy, and the occupation kernel method. Under the assumption that the dynamics are a finite linear combination of a set of basis functions, these methods establish a linear system to recover coefficients. We illuminate the structural similarities between these techniques and establish a projection property for the weak-SINDy technique. Following the overview, we analyze the error of surrogate models generated by a simplified version of weak-SINDy. In particular, under the assumption of boundedness of a composition operator given by the solution, we show that (i) the surrogate dynamics converges towards the true dynamics and (ii) the solution of the surrogate model is reasonably close to the true solution. Finally, as an application, we discuss the use of a combination of weak-SINDy surrogate modeling and proper orthogonal decomposition (POD) to build a surrogate model for partial differential equations (PDEs).

97 MATHEMATICS AND COMPUTING↗