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At least 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Rb-Sr and Sm-Nd isotopic variations in dissected crustal xenoliths

The effect of magma-xenolith interaction on the Rb-Sr and Sm-Nd isotopic systematics was investigated by studying the Rb-Sr and Sm-Nd variations in dissected crustal xenoliths sampled from different localities across Scotland. The Nd isotopic compositions were found to be virtually uniform across each xenolith, but significant variations were found in Rb, Sr, and REE concentrations, as well as in Rb/Sr and Sm/Nd ratios and Sr isotopic composition. Most of these variations appear to be inherited from the protolith, but, in one case, they have been modified by melt infiltration from the host magma. The results lend confidence to the interpretation of the isotopic and chemical compositions of xenoliths transported in basaltic magmas as reflecting their source regions, but they also highlight the potential problems of interpreting Sm-Nd model ages from metamorphic rocks.

Lee, Der-Chuen↗
NASA NTRS1999

Measurements of the Basic SR-71 Airplane Near-Field Signature

Airplane design studies have developed configuration concepts that may produce lower sonic boom annoyance levels. Since lower noise designs differ significantly from other HSCT designs, it is necessary to accurately assess their potential before HSCT final configuration decisions are made. Flight tests to demonstrate lower noise design capability by modifying an existing airframe have been proposed for the Mach 3 SR-71 reconnaissance airplane. To support the modified SR-71 proposal, baseline in-flight measurements were made of the unmodified aircraft. These measurements of SR-71 near-field sonic boom signatures were obtained by an F-16XL probe airplane at flightpath separation distances ranging from approximately 740 to 40 ft. This paper discusses the methods used to gather and analyze the flight data, and makes comparisons of these flight data with CFD results from Douglas Aircraft Corporation and NASA Langley Research Center. The CFD solutions were obtained for the near-field flow about the SR-71, and then propagated to the flight test measurement location using the program MDBOOM.

Haering, Edward A., Jr.↗
NASA NTRS2003

Rb-Sr and Sm-Nd Study of the D'Orbigny Angrite

D'Orbigny, is a relatively a new angrite find. Angrites are achondrites that show unique mineralogy and typically ancient crystallization ages. D Orbigny has been described extensively by. We have initiated a study of D Orbigny. A Pb-Pb model age of 4559 Ga has been reported. The presence of Pu-244 fission Xe in D Orbigny has also been reported. We present Sm-Nd and Rb-Sr results and a Mn-53-Cr-53 study is in progress. We had expected to find a relatively well-behaved Sm-Nd system, and distinct evidence for the Sm-146-Nd-142 system. Emphasis in this study was placed on the precise measurement of initial Sr-87/Sr-86, since primitive initial Sr-87/Sr-86 may be characteristic of the angrite parent body. Sr isotope measurements were obtained in the recently completed laboratories at JPL, using the ThermoFinnigan Triton mass spectrometer. Due to lower amounts of Nd and Sm, Sm-Nd data were obtained on the Lunatic I spectrometer at Caltech, due to established high ionization techniques, on this instrument using light rare earth oxide ions.

Tonui, E. K.↗
DOE OSTI2020

Materials Data on Sr(BS2)2 by Materials Project

Sr(BS2)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 6-coordinate geometry to nine S2- atoms. There are a spread of Sr–S bond distances ranging from 3.16–3.62 Å. In the second Sr2+ site, Sr2+ is bonded in an octahedral geometry to six equivalent S2- atoms. All Sr–S bond lengths are 3.07 Å. B3+ is bonded in a trigonal planar geometry to three S2- atoms. There is one shorter (1.80 Å) and two longer (1.82 Å) B–S bond length. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 1-coordinate geometry to three Sr2+ and one B3+ atom. In the second S2- site, S2- is bonded in a bent 120 degrees geometry to one Sr2+ and two equivalent B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlS2)2 by Materials Project

SrAl2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.13–3.17 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.14 Å) and four longer (3.16 Å) Sr–S bond lengths. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.14 Å) and four longer (3.16 Å) Sr–S bond lengths. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing AlS4 tetrahedra. There are one shorter (2.25 Å) and three longer (2.28 Å) Al–S bond lengths. In the second Al3+ site, Al3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing AlS4 tetrahedra. There are one shorter (2.25 Å) and three longer (2.28 Å) Al–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two Sr2+ and two Al3+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent Al3+ atoms. In the third S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent Al3+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(GaS2)2 by Materials Project

SrGa2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.14–3.17 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.15 Å) and four longer (3.16 Å) Sr–S bond lengths. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.15 Å) and four longer (3.16 Å) Sr–S bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing GaS4 tetrahedra. There are one shorter (2.27 Å) and three longer (2.32 Å) Ga–S bond lengths. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing GaS4 tetrahedra. There are one shorter (2.27 Å) and three longer (2.32 Å) Ga–S bond lengths. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two Ga3+ atoms. In the second S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two Ga3+ atoms. In the third S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent Ga3+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(InSe2)2 by Materials Project

SrIn2Se4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.29 Å) and four longer (3.36 Å) Sr–Se bond lengths. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (3.27 Å) and four longer (3.38 Å) Sr–Se bond lengths. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of Sr–Se bond distances ranging from 3.26–3.41 Å. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four Se2- atoms to form a mixture of corner and edge-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.59–2.66 Å. In the second In3+ site, In3+ is bonded to four Se2- atoms to form a mixture of corner and edge-sharing InSe4 tetrahedra. There are a spread of In–Se bond distances ranging from 2.59–2.66 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to two Sr2+ and two In3+ atoms to form a mixture of distorted corner and edge-sharing SeSr2In2 trigonal pyramids. In the second Se2- site, Se2- is bonded to two Sr2+ and two In3+ atoms to form a mixture of distorted corner and edge-sharing SeSr2In2 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent In3+ atoms. In the fourth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(InS2)2 by Materials Project

SrIn2S4 crystallizes in the orthorhombic Fddd space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.14 Å) and four longer (3.24 Å) Sr–S bond lengths. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are four shorter (3.12 Å) and four longer (3.27 Å) Sr–S bond lengths. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Sr–S bond distances ranging from 3.14–3.27 Å. There are two inequivalent In3+ sites. In the first In3+ site, In3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing InS4 tetrahedra. There are a spread of In–S bond distances ranging from 2.45–2.53 Å. In the second In3+ site, In3+ is bonded to four S2- atoms to form a mixture of edge and corner-sharing InS4 tetrahedra. There are a spread of In–S bond distances ranging from 2.45–2.53 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to two Sr2+ and two In3+ atoms to form a mixture of distorted edge and corner-sharing SSr2In2 trigonal pyramids. In the second S2- site, S2- is bonded to two Sr2+ and two In3+ atoms to form a mixture of distorted edge and corner-sharing SSr2In2 trigonal pyramids. In the third S2- site, S2- is bonded in a distorted rectangular see-saw-like geometry to two Sr2+ and two equivalent In3+ atoms. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to two Sr2+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(HO)2 by Materials Project

Sr(OH)2 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Sr2+ is bonded in a 7-coordinate geometry to one H1+ and six O2- atoms. The Sr–H bond length is 2.54 Å. There are a spread of Sr–O bond distances ranging from 2.54–2.66 Å. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Sr2+ and one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three equivalent Sr2+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three equivalent Sr2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlCl4)2 by Materials Project

Sr(AlCl4)2 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional and consists of two Sr(AlCl4)2 frameworks. Sr2+ is bonded to eight Cl1- atoms to form distorted SrCl8 hexagonal bipyramids that share edges with four AlCl4 tetrahedra. There are a spread of Sr–Cl bond distances ranging from 3.08–3.13 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four Cl1- atoms to form AlCl4 tetrahedra that share edges with two equivalent SrCl8 hexagonal bipyramids. All Al–Cl bond lengths are 2.16 Å. In the second Al3+ site, Al3+ is bonded to four Cl1- atoms to form AlCl4 tetrahedra that share edges with two equivalent SrCl8 hexagonal bipyramids. All Al–Cl bond lengths are 2.16 Å. There are eight inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the third Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the fourth Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the fifth Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the sixth Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the seventh Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the eighth Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(PO3)2 by Materials Project

Sr(PO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Sr–O bond distances ranging from 2.50–2.76 Å. In the second Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Sr–O bond distances ranging from 2.53–2.83 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.51 Å) and two longer (1.60 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sr2+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Sr2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two Sr2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AsRh)2 by Materials Project

SrRh2As2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr is bonded in a distorted body-centered cubic geometry to eight equivalent As atoms. All Sr–As bond lengths are 3.33 Å. Rh is bonded to four equivalent As atoms to form a mixture of distorted edge and corner-sharing RhAs4 tetrahedra. All Rh–As bond lengths are 2.48 Å. As is bonded in a 8-coordinate geometry to four equivalent Sr and four equivalent Rh atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlCl4)2 by Materials Project

Sr(AlCl4)2 crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional and consists of two Sr(AlCl4)2 frameworks. Sr2+ is bonded to eight Cl1- atoms to form distorted SrCl8 hexagonal bipyramids that share edges with four equivalent AlCl4 tetrahedra. There are four shorter (3.08 Å) and four longer (3.13 Å) Sr–Cl bond lengths. Al3+ is bonded to four Cl1- atoms to form AlCl4 tetrahedra that share edges with two equivalent SrCl8 hexagonal bipyramids. All Al–Cl bond lengths are 2.16 Å. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlCl4)2 by Materials Project

Sr(AlCl4)2 crystallizes in the monoclinic P2/c space group. The structure is two-dimensional and consists of one Sr(AlCl4)2 sheet oriented in the (1, 0, 0) direction. Sr2+ is bonded in a 8-coordinate geometry to eight Cl1- atoms. There are six shorter (3.09 Å) and two longer (3.13 Å) Sr–Cl bond lengths. Al3+ is bonded in a tetrahedral geometry to four Cl1- atoms. There are two shorter (2.15 Å) and two longer (2.16 Å) Al–Cl bond lengths. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Sr2+ and one Al3+ atom. In the second Cl1- site, Cl1- is bonded in a distorted bent 120 degrees geometry to one Sr2+ and one Al3+ atom. In the third Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom. In the fourth Cl1- site, Cl1- is bonded in a distorted L-shaped geometry to one Sr2+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(AlH)2 by Materials Project

SrAl2H2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one SrAl2H2 sheet oriented in the (0, 0, 1) direction. Sr is bonded in a hexagonal planar geometry to six equivalent H atoms. All Sr–H bond lengths are 2.66 Å. Al is bonded in a single-bond geometry to one H atom. The Al–H bond length is 1.71 Å. H is bonded in a distorted single-bond geometry to three equivalent Sr and one Al atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(SnAs)2 by Materials Project

Sr(SnAs)2 crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Sr(SnAs)2 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded to six equivalent As3- atoms to form edge-sharing SrAs6 octahedra. All Sr–As bond lengths are 3.17 Å. Sn2+ is bonded in a distorted trigonal non-coplanar geometry to three equivalent As3- atoms. All Sn–As bond lengths are 2.83 Å. As3- is bonded to three equivalent Sr2+ and three equivalent Sn2+ atoms to form a mixture of edge and corner-sharing AsSr3Sn3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(IO3)2 by Materials Project

Sr(IO3)2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is two-dimensional and consists of two Sr(IO3)2 sheets oriented in the (0, 0, 1) direction. Sr2+ is bonded to seven O2- atoms to form distorted corner-sharing SrO7 pentagonal bipyramids. There are a spread of Sr–O bond distances ranging from 2.50–2.67 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+ and one I5+ atom. The O–I bond length is 1.85 Å. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sr2+ and one I5+ atom. The O–I bond length is 1.84 Å. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and one I5+ atom. The O–I bond length is 1.84 Å. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Sr2+ and one I5+ atom. The O–I bond length is 1.85 Å. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Sr2+ and two I5+ atoms. There are one shorter (1.86 Å) and one longer (2.67 Å) O–I bond lengths. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Sr2+ and one I5+ atom. The O–I bond length is 1.84 Å. There are two inequivalent I5+ sites. In the first I5+ site, I5+ is bonded in a 3-coordinate geometry to four O2- atoms. In the second I5+ site, I5+ is bonded in a 3-coordinate geometry to three O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr(PRh)2 by Materials Project

SrRh2P2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sr is bonded in a distorted body-centered cubic geometry to eight equivalent P atoms. All Sr–P bond lengths are 3.27 Å. Rh is bonded to four equivalent P atoms to form a mixture of distorted edge and corner-sharing RhP4 tetrahedra. All Rh–P bond lengths are 2.37 Å. P is bonded in a 8-coordinate geometry to four equivalent Sr and four equivalent Rh atoms.

36 MATERIALS SCIENCE↗