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At least 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Cr(BMo)2 by Materials Project

Cr(MoB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.33 Å) and four longer (2.34 Å) Mo–B bond lengths. Cr2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Cr–B bond lengths are 2.35 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Mo2+, two equivalent Cr2+, and one B3- atom. The B–B bond length is 1.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KLiWO4 by Materials Project

KLiWO4 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. K1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All K–O bond lengths are 3.50 Å. Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with four equivalent WO4 tetrahedra. There is three shorter (1.90 Å) and one longer (1.94 Å) Li–O bond length. W6+ is bonded to four O2- atoms to form WO4 tetrahedra that share corners with four equivalent LiO4 tetrahedra. There is three shorter (1.81 Å) and one longer (1.82 Å) W–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to three equivalent K1+, one Li1+, and one W6+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Li1+ and one W6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KLiMoO4 by Materials Project

LiKMoO4 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. K1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All K–O bond lengths are 3.47 Å. Li1+ is bonded to four O2- atoms to form LiO4 tetrahedra that share corners with four equivalent MoO4 tetrahedra. There is three shorter (1.89 Å) and one longer (1.94 Å) Li–O bond length. Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with four equivalent LiO4 tetrahedra. There is three shorter (1.79 Å) and one longer (1.80 Å) Mo–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to three equivalent K1+, one Li1+, and one Mo6+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Li1+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Amorphization mechanism of SrIrO 3 electrocatalyst: How oxygen redox initiates ionic diffusion and structural reorganization

The use of renewable electricity to prepare materials and fuels from abundant molecules offers a tantalizing opportunity to address concerns over energy and materials sustainability. The oxygen evolution reaction (OER) is integral to nearly all material and fuel electrosyntheses. However, very little is known about the structural evolution of the OER electrocatalyst, especially the amorphous layer that forms from the crystalline structure. Here, we investigate the interfacial transformation of the SrIrO 3 OER electrocatalyst. The SrIrO 3 amorphization is initiated by the lattice oxygen redox, a step that allows Sr 2+ to diffuse and O 2− to reorganize the SrIrO 3 structure. This activation turns SrIrO 3 into a highly disordered Ir octahedral network with Ir square-planar motif. The final Sr y IrO x exhibits a greater degree of disorder than IrO x made from other processing methods. Our results demonstrate that the structural reorganization facilitated by coupled ionic diffusions is essential to the disordered structure of the SrIrO 3 electrocatalyst.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1984

Analysis of some acoustics-jet flow interaction problems

Analytical problems in the interactions between the mean-shear flows and the acoustic field in the planar and circular jets are examined. These problems are basic in understanding the effects of coherent large structure on the generation and complications of sound in a sub-sonic jet. Three problems were investigated: (1) spatial (vs. temporal) normal mode analysis in a planar jets; (2) a slightly divergent, planar jet; and (3) acoustic waves in an axisymmetrical jet.

Chow, P. L.↗
DOE OSTI2020

Materials Data on CaMgNiH4 by Materials Project

CaMgNiH4 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. Ca is bonded in a hexagonal planar geometry to six H atoms. There are three shorter (2.45 Å) and three longer (2.52 Å) Ca–H bond lengths. Mg is bonded in a 6-coordinate geometry to six equivalent H atoms. There are three shorter (2.10 Å) and three longer (2.15 Å) Mg–H bond lengths. Ni is bonded in a tetrahedral geometry to four H atoms. All Ni–H bond lengths are 1.59 Å. There are two inequivalent H sites. In the first H site, H is bonded in a distorted rectangular see-saw-like geometry to one Ca, two equivalent Mg, and one Ni atom. In the second H site, H is bonded to three equivalent Ca and one Ni atom to form corner-sharing HCa3Ni trigonal pyramids.

36 MATERIALS SCIENCE↗
NASA NTRS1998

Application of a Planar Doppler Velocimetry System to a High Reynolds Number Compressible Jet

A Planar Doppler Velocimetry (PDV) system has been constructed and used to investigate the instantaneous turbulent velocity structure of a round high-speed compressible air jet with a low-speed co-flow. The exit condition was Mach=0.85 at ambient pressure, yielding a Reynolds number of about 650,000 on diameter. The PDV system was installed at NASA Langley Research Center in the Small Anechoic Jet Facility (SAJF), a chamber in which both the acoustic and aerodynamic properties of jets can be studied. For this test, the goal was to gather data which can be used to relate the turbulence structure of the jet to the levels and character of the acoustic noise produced by the jet. The current PDV system can acquire single-velocity-component, single-shot, planar images (15ns exposures) at 30 Hz. For this paper, the primary data set consists of 240 frames of velocity data acquired with both the jet and the low-speed co-flow seeded with light-scattering articles. Thus, velocities could be measured everywhere in the jet shear layer, both in the jet fluid and in the entrained co-flow. Some data were also taken with only the jet flow seeded. These provided mixing concentration images along with the reduced velocity fields. Other images were taken with only the co-flow seeded. These produced unique quantitative images of high speed entrainment. Optical "laser speckle" noise is the largest source of random noise in pulsed PDV systems. Components for the PDV imaging system were specifically selected to minimize speckle noise. To reduce systematic velocity errors due to laser drift, a frequency monitoring reference leg with a temperature-tuned reference iodine cell, was employed. In the course of this study, a novel flow seeder was developed. It enabled continuously variable seeding of the flow with particles of Sheared Pyrogenic Amorphous Hydrophobic Silica (SPAHS). The seeder comprised a dry fluidized bed hopper and a supersonic nozzle "pickup." Shearing action in the pickup dispersed the seed material in an exceptionally fine cloud (approximately 0.3 micron). These particles followed the flow well, did not clump or cake on screens or model surfaces, and were not susceptible to evaporation. Because of the refractory nature of the particles, SPAHS seeding should also be applicable to anticipated future testing at high temperatures.

Smith, Michael W.↗
DOE OSTI2020

Materials Data on Al11AgO17 by Materials Project

AgAl11O17 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ag1+ is bonded in a hexagonal planar geometry to six O2- atoms. There are four shorter (2.75 Å) and two longer (2.89 Å) Ag–O bond lengths. There are five inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.03 Å. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with six AlO6 octahedra and a cornercorner with one AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–56°. There are a spread of Al–O bond distances ranging from 1.70–1.80 Å. In the third Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–58°. There is three shorter (1.82 Å) and one longer (1.83 Å) Al–O bond length. In the fourth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with five AlO4 tetrahedra and edges with five AlO6 octahedra. There are a spread of Al–O bond distances ranging from 1.82–2.07 Å. In the fifth Al3+ site, Al3+ is bonded to six O2- atoms to form AlO6 octahedra that share corners with six equivalent AlO4 tetrahedra and edges with six AlO6 octahedra. There is four shorter (1.91 Å) and two longer (1.92 Å) Al–O bond length. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three Al3+ atoms. In the second O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ag1+ and three Al3+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ag1+ and two equivalent Al3+ atoms. In the fifth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the sixth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Al3+ atoms. In the seventh O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaAlSiO4 by Materials Project

NaAlSiO4 crystallizes in the cubic P2_13 space group. The structure is three-dimensional. Na1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All Na–O bond lengths are 2.33 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent SiO4 tetrahedra. There is one shorter (1.74 Å) and three longer (1.77 Å) Al–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with four equivalent AlO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Al3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MgWO3 by Materials Project

MgWO3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. Mg2+ is bonded in a pentagonal planar geometry to five O2- atoms. There are a spread of Mg–O bond distances ranging from 2.18–2.23 Å. W4+ is bonded to six O2- atoms to form distorted corner-sharing WO6 octahedra. The corner-sharing octahedral tilt angles are 18°. There are a spread of W–O bond distances ranging from 1.96–2.24 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Mg2+ and two equivalent W4+ atoms. In the second O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Mg2+ and two equivalent W4+ atoms. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Mg2+ and two equivalent W4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KU2(PO4)3 by Materials Project

KU2(PO4)3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. K1+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All K–O bond lengths are 2.91 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six equivalent PO4 tetrahedra. There are three shorter (2.24 Å) and three longer (2.27 Å) U–O bond lengths. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent UO6 octahedra. The corner-sharing octahedra tilt angles range from 26–31°. All P–O bond lengths are 1.55 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one P5+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaGe2(PO4)3 by Materials Project

NaGe2P3O12 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Na1+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.43 Å. Ge4+ is bonded to six O2- atoms to form GeO6 octahedra that share corners with six equivalent PO4 tetrahedra. There is three shorter (1.87 Å) and three longer (1.90 Å) Ge–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent GeO6 octahedra. The corner-sharing octahedra tilt angles range from 30–35°. All P–O bond lengths are 1.54 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ge4+, and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Ge4+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KZr2(AsO4)3 by Materials Project

KZr2(AsO4)3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. K1+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All K–O bond lengths are 2.87 Å. Zr4+ is bonded to six O2- atoms to form ZrO6 octahedra that share corners with six equivalent AsO4 tetrahedra. There are three shorter (2.09 Å) and three longer (2.12 Å) Zr–O bond lengths. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with four equivalent ZrO6 octahedra. The corner-sharing octahedral tilt angles are 30°. All As–O bond lengths are 1.71 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Zr4+ and one As5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one Zr4+, and one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiBO3 by Materials Project

BiBO3 is Calcite-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.38 Å) and two longer (1.39 Å) B–O bond length. Bi3+ is bonded to six O2- atoms to form a mixture of distorted edge and corner-sharing BiO6 octahedra. The corner-sharing octahedral tilt angles are 57°. There are a spread of Bi–O bond distances ranging from 2.22–2.59 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and two equivalent Bi3+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one B3+ and two equivalent Bi3+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and two equivalent Bi3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Bi2BO5 by Materials Project

BBi2O5 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.38 Å) and one longer (1.39 Å) B–O bond length. Bi+3.50+ is bonded to seven O2- atoms to form a mixture of distorted corner and edge-sharing BiO7 pentagonal bipyramids. There are a spread of Bi–O bond distances ranging from 2.27–2.52 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and two equivalent Bi+3.50+ atoms. In the second O2- site, O2- is bonded to four equivalent Bi+3.50+ atoms to form a mixture of corner and edge-sharing OBi4 tetrahedra. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one B3+ and two equivalent Bi+3.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ti11BeO20 by Materials Project

BeTi11O20 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Be2+ is bonded in a trigonal planar geometry to three O2- atoms. All Be–O bond lengths are 1.61 Å. There are eleven inequivalent Ti+3.45+ sites. In the first Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 36–58°. There are a spread of Ti–O bond distances ranging from 1.91–2.12 Å. In the second Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner, edge, and face-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–57°. There are a spread of Ti–O bond distances ranging from 1.92–2.14 Å. In the third Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 44–57°. There are a spread of Ti–O bond distances ranging from 1.89–2.20 Å. In the fourth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 40–57°. There are a spread of Ti–O bond distances ranging from 1.93–2.11 Å. In the fifth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 21–54°. There are a spread of Ti–O bond distances ranging from 1.90–2.16 Å. In the sixth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 45–58°. There are a spread of Ti–O bond distances ranging from 1.97–2.08 Å. In the seventh Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 13–57°. There are a spread of Ti–O bond distances ranging from 1.91–2.14 Å. In the eighth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 9–55°. There are a spread of Ti–O bond distances ranging from 1.95–2.09 Å. In the ninth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner, edge, and face-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 9–55°. There are a spread of Ti–O bond distances ranging from 1.88–2.10 Å. In the tenth Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 44–57°. There are a spread of Ti–O bond distances ranging from 1.91–2.14 Å. In the eleventh Ti+3.45+ site, Ti+3.45+ is bonded to six O2- atoms to form a mixture of corner and edge-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 9–55°. There are a spread of Ti–O bond distances ranging from 1.94–2.17 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Be2+ and three Ti+3.45+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the fourth O2- site, O2- is bonded in a distorted see-saw-like geometry to four Ti+3.45+ atoms. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to three Ti+3.45+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the seventh O2- site, O2- is bonded to four Ti+3.45+ atoms to form edge-sharing OTi4 trigonal pyramids. In the eighth O2- site, O2- is bonded to four Ti+3.45+ atoms to form edge-sharing OTi4 trigonal pyramids. In the ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the tenth O2- site, O2- is bonded in a distorted T-shaped geometry to three Ti+3.45+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to three Ti+3.45+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Ti+3.45+ atoms. In the fourteenth O2- site, O2- is bonded in a trigonal planar geometry to three Ti+3.45+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Be2+ and three Ti+3.45+ atoms. In the sixteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ti+3.45+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Be2+ and three Ti+3.45+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to four Ti+3.45+ atoms. In the nineteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to four Ti+3.45+ atoms. In the twentieth O2- site, O2- is bonded in a T-shaped geometry to three Ti+3.45+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaIn2 by Materials Project

CaIn2 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ca is bonded in a distorted hexagonal planar geometry to six equivalent In atoms. All Ca–In bond lengths are 3.18 Å. In is bonded in a 7-coordinate geometry to three equivalent Ca and four equivalent In atoms. There are one shorter (3.07 Å) and three longer (3.27 Å) In–In bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2O by Materials Project

Cs2O is zeta iron carbide structured and crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. Cs1+ is bonded in a distorted trigonal planar geometry to three equivalent O2- atoms. There are two shorter (2.84 Å) and one longer (3.27 Å) Cs–O bond lengths. O2- is bonded to six equivalent Cs1+ atoms to form a mixture of edge and corner-sharing OCs6 octahedra. The corner-sharing octahedral tilt angles are 52°.

36 MATERIALS SCIENCE↗