Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “K”

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 901 records · Page 50
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on K(FeP)2 by Materials Project

K(FeP)2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. All K–P bond lengths are 3.40 Å. Fe+2.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing FeP4 tetrahedra. All Fe–P bond lengths are 2.19 Å. P3- is bonded in a 4-coordinate geometry to four equivalent K1+ and four equivalent Fe+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(WO3)3 by Materials Project

K(WO3)3 crystallizes in the orthorhombic Cmm2 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (3.11 Å) and four longer (3.15 Å) K–O bond lengths. There are two inequivalent W+5.67+ sites. In the first W+5.67+ site, W+5.67+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 0–31°. There is two shorter (1.94 Å) and four longer (1.95 Å) W–O bond length. In the second W+5.67+ site, W+5.67+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 0–33°. There are a spread of W–O bond distances ranging from 1.94–1.96 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two W+5.67+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two equivalent W+5.67+ atoms. In the third O2- site, O2- is bonded in a linear geometry to two equivalent W+5.67+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent W+5.67+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(CoP)2 by Materials Project

K(CoP)2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. All K–P bond lengths are 3.36 Å. Co+2.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing CoP4 tetrahedra. All Co–P bond lengths are 2.20 Å. P3- is bonded in a 8-coordinate geometry to four equivalent K1+ and four equivalent Co+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(Zr3Te4)4 by Materials Project

K(Zr3Te4)4 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. K1+ is bonded in a distorted hexagonal planar geometry to six Te2- atoms. There are two shorter (3.73 Å) and four longer (3.74 Å) K–Te bond lengths. There are six inequivalent Zr+2.58+ sites. In the first Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.91–3.01 Å. In the second Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.91–3.02 Å. In the third Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.91–3.03 Å. In the fourth Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.92–3.02 Å. In the fifth Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.92–3.02 Å. In the sixth Zr+2.58+ site, Zr+2.58+ is bonded to six Te2- atoms to form a mixture of face, edge, and corner-sharing ZrTe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Te bond distances ranging from 2.91–3.01 Å. There are eight inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 4-coordinate geometry to four Zr+2.58+ atoms. In the second Te2- site, Te2- is bonded in a 5-coordinate geometry to one K1+ and four Zr+2.58+ atoms. In the third Te2- site, Te2- is bonded in a 4-coordinate geometry to four Zr+2.58+ atoms. In the fourth Te2- site, Te2- is bonded in a 5-coordinate geometry to one K1+ and four Zr+2.58+ atoms. In the fifth Te2- site, Te2- is bonded in a 5-coordinate geometry to one K1+ and four Zr+2.58+ atoms. In the sixth Te2- site, Te2- is bonded in a 4-coordinate geometry to four Zr+2.58+ atoms. In the seventh Te2- site, Te2- is bonded to six Zr+2.58+ atoms to form distorted face-sharing TeZr6 pentagonal pyramids. In the eighth Te2- site, Te2- is bonded to six Zr+2.58+ atoms to form distorted face-sharing TeZr6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(Cu2Sb)2 by Materials Project

K(Cu2Sb)2 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. K1+ is bonded to six equivalent Sb3- atoms to form distorted edge-sharing KSb6 octahedra. All K–Sb bond lengths are 3.50 Å. There are two inequivalent Cu+1.25+ sites. In the first Cu+1.25+ site, Cu+1.25+ is bonded in a 4-coordinate geometry to four equivalent Sb3- atoms. There are one shorter (2.71 Å) and three longer (2.86 Å) Cu–Sb bond lengths. In the second Cu+1.25+ site, Cu+1.25+ is bonded in a trigonal non-coplanar geometry to three equivalent Sb3- atoms. All Cu–Sb bond lengths are 2.60 Å. Sb3- is bonded in a 10-coordinate geometry to three equivalent K1+ and seven Cu+1.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(Ti3Se4)2 by Materials Project

K(Ti3Se4)2 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six equivalent Se2- atoms. All K–Se bond lengths are 3.39 Å. Ti+2.50+ is bonded to six Se2- atoms to form a mixture of corner, edge, and face-sharing TiSe6 octahedra. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Ti–Se bond distances ranging from 2.55–2.69 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to one K1+ and four equivalent Ti+2.50+ atoms. In the second Se2- site, Se2- is bonded to six equivalent Ti+2.50+ atoms to form distorted face-sharing SeTi6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(ThTe3)2 by Materials Project

K(ThTe3)2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. K1+ is bonded in a distorted body-centered cubic geometry to eight Te+1.50- atoms. There are four shorter (3.63 Å) and four longer (3.74 Å) K–Te bond lengths. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a 8-coordinate geometry to eight Te+1.50- atoms. There are a spread of Th–Te bond distances ranging from 3.21–3.28 Å. In the second Th4+ site, Th4+ is bonded in a 8-coordinate geometry to eight Te+1.50- atoms. There are a spread of Th–Te bond distances ranging from 3.20–3.28 Å. There are four inequivalent Te+1.50- sites. In the first Te+1.50- site, Te+1.50- is bonded to four Th4+ atoms to form a mixture of distorted corner and edge-sharing TeTh4 trigonal pyramids. In the second Te+1.50- site, Te+1.50- is bonded to four Th4+ atoms to form a mixture of distorted corner and edge-sharing TeTh4 trigonal pyramids. In the third Te+1.50- site, Te+1.50- is bonded in a 6-coordinate geometry to two equivalent K1+, two equivalent Th4+, and two equivalent Te+1.50- atoms. There are one shorter (3.08 Å) and one longer (3.09 Å) Te–Te bond lengths. In the fourth Te+1.50- site, Te+1.50- is bonded in a 4-coordinate geometry to two equivalent K1+ and two equivalent Th4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(PRu)2 by Materials Project

K(RuP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight equivalent P3- atoms. All K–P bond lengths are 3.53 Å. Ru+2.50+ is bonded to four equivalent P3- atoms to form a mixture of corner and edge-sharing RuP4 tetrahedra. All Ru–P bond lengths are 2.31 Å. P3- is bonded in a 8-coordinate geometry to four equivalent K1+ and four equivalent Ru+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(Mo2O3)4 by Materials Project

K(Mo2O3)4 crystallizes in the monoclinic P2 space group. The structure is three-dimensional. K1+ is bonded in a 12-coordinate geometry to six O2- atoms. There are a spread of K–O bond distances ranging from 3.09–3.20 Å. There are four inequivalent Mo+2.88+ sites. In the first Mo+2.88+ site, Mo+2.88+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six MoO5 square pyramids and corners with two equivalent MoO4 tetrahedra. There are a spread of Mo–O bond distances ranging from 1.96–2.05 Å. In the second Mo+2.88+ site, Mo+2.88+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with six MoO5 square pyramids and corners with two equivalent MoO4 tetrahedra. There are a spread of Mo–O bond distances ranging from 1.94–2.06 Å. In the third Mo+2.88+ site, Mo+2.88+ is bonded to five O2- atoms to form MoO5 square pyramids that share corners with six MoO4 tetrahedra and edges with two equivalent MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.13–2.17 Å. In the fourth Mo+2.88+ site, Mo+2.88+ is bonded to five O2- atoms to form MoO5 square pyramids that share corners with six MoO4 tetrahedra and edges with two equivalent MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.13–2.17 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Mo+2.88+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one K1+ and three Mo+2.88+ atoms. In the third O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Mo+2.88+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one K1+ and three Mo+2.88+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one K1+ and three Mo+2.88+ atoms. In the sixth O2- site, O2- is bonded in a trigonal planar geometry to three Mo+2.88+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(Nb3Se4)2 by Materials Project

K(Nb3Se4)2 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to six equivalent Se2- atoms. All K–Se bond lengths are 3.34 Å. Nb+2.50+ is bonded to six Se2- atoms to form a mixture of distorted edge, corner, and face-sharing NbSe6 octahedra. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of Nb–Se bond distances ranging from 2.61–2.85 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six equivalent Nb+2.50+ atoms to form distorted face-sharing SeNb6 pentagonal pyramids. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one K1+ and four equivalent Nb+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(NpSe3)2 by Materials Project

K(NpSe3)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. K1+ is bonded in a distorted body-centered cubic geometry to eight equivalent Se2- atoms. All K–Se bond lengths are 3.41 Å. Np+5.50+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Np–Se bond distances ranging from 2.89–2.95 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 4-coordinate geometry to two equivalent K1+ and two equivalent Np+5.50+ atoms. In the second Se2- site, Se2- is bonded to four equivalent Np+5.50+ atoms to form a mixture of distorted edge and corner-sharing SeNp4 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(AsRu)2 by Materials Project

K(RuAs)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K1+ is bonded in a body-centered cubic geometry to eight equivalent As3- atoms. All K–As bond lengths are 3.50 Å. Ru+2.50+ is bonded to four equivalent As3- atoms to form a mixture of edge and corner-sharing RuAs4 tetrahedra. All Ru–As bond lengths are 2.43 Å. As3- is bonded in a 8-coordinate geometry to four equivalent K1+ and four equivalent Ru+2.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K(AuO2)2 by Materials Project

K(AuO2)2 crystallizes in the tetragonal P4_2/mmc space group. The structure is three-dimensional. K1+ is bonded to eight equivalent O2- atoms to form distorted corner-sharing KO8 hexagonal bipyramids. All K–O bond lengths are 2.86 Å. Au+3.50+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Au–O bond lengths are 2.02 Å. O2- is bonded in a distorted see-saw-like geometry to two equivalent K1+ and two equivalent Au+3.50+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS1988

Evidence of volcanic ash at a K-T boundary section: Ocean drilling program hole 690 C, Maud Rise, Weddell Sea off East Antarctica

Rare vitric volcanogenic ash but more abundant clay minerals considered volcanogenic in origin are associated with an expanded and essentially complete K-T boundary sequence from Ocean Drilling Project (ODP) Hole 690 C on Maud Rise in the Weddell Sea off East Antarctica. Results at this writing are preliminary and are still based to some extent on shipboard descriptions. Further shore-based studies are in progress. It would appear, however, that the presence of volcanic ash and altered ash in the Danian section beginning at the biostratigraphically and paleomagnetically determined K-T boundary on Maud Rise can be cited as evidence of significant volcanic activity within the South Atlantic-Indian Ocean sector of the Southern Ocean coincident with the time of biotic crises at the end of the Maestrichtian. This is a postulated time of tectonic and volcanic activity within this Southern Hemisphere region, including possible initiation of the Reunion hot spot and a peak in explosive volcanism on Walvis Ridge (1) among other events. A causal relationship with the biotic crisis is possible and volcanism should be given serious consideration as a testable working hypothesis to explain these extinctions.

Wise, S. W.↗
NASA NTRS1991

1000 to 1300 K slow plastic compression properties of Al-deficient NiAl

Nickel aluminides containing 37, 38.5 and 40 at. pct Al have been fabricated by XD synthesis and hot pressing. Such materials were compression tested in air under constant velocity conditions between 1000 and 1300 K. Examination of the microstructures of hot pressed and compression tested aluminides indicated that the structure consisted of two phases, gamma-prime and NiAl, for essentially all conditions, where gamma-prime was usually found on the NiAl grain boundaries. The stress-strain behavior of all three intermetallics was similar where flow at a nominally constant stress occurred after about two-percent plastic deformation. Furthermore, the 1000 to 1300 K flow stress-strain rate properties are nearly identical for these materials, and they are much lower than those for XD processed Ni-50Al. The overall deformation of the two phase nickel aluminides appears to be controlled by dislocation climb in NiAl rather than processes in gamma-prime.

Whittenberger, J. D.↗
NASA NTRS1991

1000 to 1200 K time-dependent compressive deformation of single-crystalline and polycrystalline B2 Ni-40Al

The 1000-K and 1200-K time-dependent deformation of 100-line-oriented and non-100-line-oriented single crystals of Ni-40Al (made by a modified Bridgman technique) was examined over a large range of strain rates (from 0.1 to 10 to the -7th per sec). The results were compared with those for polycrystalline Ni-40Al made by hot pressing XD synthesized powder. The results from measurements of slow-plastic-strain-rate properties of the two materials show that single crystals offer no strength advantage over polycrystalline material. Both forms were found to deform via a dislocation climb mechanism.

Whittenberger, J. D.↗
NASA NTRS1993

Resolving the iron K line in Cygnus X-2 - An observation with BBXRT

The Astro-1 Space Shuttle payload's Broad Band X-ray telescope has been used to obtain high-quality, moderate-resolution spectroscopy of Cygnus X-2 which allow the resolving of the physical width of the 6.7 keV Fe K-alpha feature with a factor-of-4 energy resolution improvement over past experiments. Three possible sites are noted for the Fe K-alpha emission: the accretion disk, its corona, and the source itself. It is judged that reflection from the accretion disk can generate a line of the observed energy, width, and equivalent width, provided that the disk surface is highly ionized.

Smale, A. P.↗
NASA NTRS2007

Relativistic Iron K Emission and Absorption in the Seyfert 1.9 Galaxy MCG-05-23-16

We present the results of the simultaneous deep XMM-Newton and Chandra observations of the bright Seyfert 1.9 galaxy MCG-5-23-16, which is thought to have one of the best known examples of a relativistically broadened iron Kalpha line. We detected a narrow sporadic absorption line at 7.7 keV which appears to be variable on a time-scale of 20 ksec. If associated with FeXXVI this absorption is indicative of a possible variable high ionization, high velocity outflow. The time averaged spectral analysis shows that the iron K-shell complex is best modeled with an unresolved narrow emission component (FWHM less than 5000 kilometers per second, EW approx. 60 eV) plus a broad component. This latter component has FWHM approx. 44000 kilometers per second, an EW approx. 50 eV and its profile is well described with an emission line originating from the accretion disk viewed with an inclination angle approx. 40 deg. and with the emission arising from within a few tens of gravitational radii of the central black hole. The time-resolved spectral analysis of the XMM-Newton EPIC-pn spectrum shows that both the narrow and broad components of the Fe K emission line appear to be constant within the errors. The analysis of the XMM-Newton/RGS spectrum reveals that the soft X-ray emission of MCG-5-23-16 is likely dominated by several emission lines superimposed on an unabsorbed scattered power-law continuum. The lack of strong Fe L shell emission together with the detection of a strong forbidden line in the O VII triplet supports a scenario where the soft X ray emission lines are produced in a plasma photoionized by the nuclear emission.

Braito, V.↗