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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on KBa2Cd2Sb3 by Materials Project

KBa2Cd2Sb3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 4-coordinate geometry to four Sb3- atoms. There are two shorter (3.52 Å) and two longer (3.67 Å) K–Sb bond lengths. There are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 6-coordinate geometry to six Sb3- atoms. There are a spread of Ba–Sb bond distances ranging from 3.54–3.96 Å. In the second Ba2+ site, Ba2+ is bonded to six Sb3- atoms to form BaSb6 octahedra that share corners with two equivalent BaSb6 octahedra, corners with five equivalent CdSb4 tetrahedra, edges with two equivalent BaSb6 octahedra, edges with four equivalent CdSb4 tetrahedra, and a faceface with one CdSb4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Ba–Sb bond distances ranging from 3.49–3.70 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four Sb3- atoms to form CdSb4 tetrahedra that share corners with five equivalent BaSb6 octahedra, corners with seven CdSb4 tetrahedra, and a faceface with one BaSb6 octahedra. The corner-sharing octahedra tilt angles range from 36–48°. There are a spread of Cd–Sb bond distances ranging from 2.97–3.09 Å. In the second Cd2+ site, Cd2+ is bonded to four Sb3- atoms to form CdSb4 tetrahedra that share corners with seven CdSb4 tetrahedra and edges with four equivalent BaSb6 octahedra. There are a spread of Cd–Sb bond distances ranging from 2.92–3.17 Å. There are three inequivalent Sb3- sites. In the first Sb3- site, Sb3- is bonded in a 8-coordinate geometry to five Ba2+ and three Cd2+ atoms. In the second Sb3- site, Sb3- is bonded in a 8-coordinate geometry to two equivalent K1+, three Ba2+, and three Cd2+ atoms. In the third Sb3- site, Sb3- is bonded in a 8-coordinate geometry to two equivalent K1+, four Ba2+, and two Cd2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Field Scoping Study of Gamma-Ray Measurement of UF 6 Cristillini Samples with CZT and HPGe Detectors

A field scoping study was conducted to evaluate the ability of Cd-Zn-Te (CZT) detectors and High Purity Germanium (HPGe) detectors to quantify the U-235 enrichment in UF 6 samples collected on alumina in P-10 tubes, similar to the Cristillini method of sample collection for analysis by mass spectrometry. With in-field gamma-ray spectroscopy methods, international safeguards and verification missions could benefit from quick in-field confirmation of declared enrichment values prior to or without the need for additional shipping, sample preparation and analysis. Samples of depleted (DU), low-enriched (LEU) and high-assay low-enriched (HALEU) uranium were collected on Cristillini-type alumina in P-10 tubes and measured with two H3D, Inc. M400 CZT detectors as well as a Canberra Falcon HPGe detector. The M400 detectors were able to confirm enrichment in the DU and LEU samples but not the HALEU sample in measurements 8-40 hrs after collection. The Falcon system was able to confirm enrichment in all three samples. Improvements in detector geometry, increase in number of detectors as well as increase sample mass loading may allow measurement of U-235 enrichment in these types of samples within 4-8hrs of collection with 5-10% uncertainty.

98 - NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL↗
DOE OSTI2020

Materials Data on CaMg14CdO16 by Materials Project

CaMg14CdO16 is alpha Po-derived structured and crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent CdO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ca–O bond distances ranging from 2.17–2.29 Å. There are nine inequivalent Mg2+ sites. In the first Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.04–2.18 Å. In the second Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.01 Å) and four longer (2.18 Å) Mg–O bond lengths. In the third Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are a spread of Mg–O bond distances ranging from 2.16–2.19 Å. In the fourth Mg2+ site, Mg2+ is bonded to six O2- atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.17 Å) and three longer (2.18 Å) Mg–O bond lengths. In the fifth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.11–2.22 Å. In the sixth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Mg–O bond distances ranging from 2.12–2.21 Å. In the seventh Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CaO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.11–2.22 Å. In the eighth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Mg–O bond distances ranging from 2.12–2.21 Å. In the ninth Mg2+ site, Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one CaO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. There are a spread of Mg–O bond distances ranging from 2.12–2.22 Å. Cd2+ is bonded to six O2- atoms to form CdO6 octahedra that share corners with two equivalent CaO6 octahedra, corners with two equivalent MgO6 octahedra, corners with two equivalent CdO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Cd–O bond distances ranging from 2.18–2.32 Å. There are eleven inequivalent O2- sites. In the first O2- site, O2- is bonded to one Ca2+ and five Mg2+ atoms to form OCaMg5 octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the second O2- site, O2- is bonded to five Mg2+ and one Cd2+ atom to form OMg5Cd octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the third O2- site, O2- is bonded to five Mg2+ and one Cd2+ atom to form OMg5Cd octahedra that share corners with six OCaMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. Both O–Mg bond lengths are 2.17 Å. In the fourth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the fifth O2- site, O2- is bonded to two equivalent Ca2+ and four Mg2+ atoms to form OCa2Mg4 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O2- site, O2- is bonded to four Mg2+ and two equivalent Cd2+ atoms to form OMg4Cd2 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OCa2Mg4 octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OMg4Cd2 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the ninth O2- site, O2- is bonded to one Ca2+, four Mg2+, and one Cd2+ atom to form OCaMg4Cd octahedra that share corners with six OCaMg4Cd octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the tenth O2- site, O2- is bonded to one Ca2+, four Mg2+, and one Cd2+ atom to form OCaMg4Cd octahedra that share corners with six OCaMg4Cd octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are two shorter (2.18 Å) and two longer (2.22 Å) O–Mg bond lengths. In the eleventh O2- site, O2- is bonded to six Mg2+ atoms to form OMg6 octahedra that share corners with six OCaMg4Cd octahedra and edges with twelve OCaMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–1°.

36 MATERIALS SCIENCE↗
NASA NTRS1993

Progress in p(+)n InP solar cells fabricated by thermal diffusion

The performance results of our most recently thermally diffused InP solar cells using the p(+)n (Cd,S) structures are presented. We have succeeded in fabricating cells with measured AMO, 25 C V(sub oc) exceeding 880 mV (bare cells) which to the best of our knowledge is higher than previously reported V(sub oc) values for any InP homojunction solar cells. The cells were fabricated by thinning the emitter, after Au-Zn front contacting, from its initial thickness of about 4.5 microns to about 0.6 microns. After thinning, the exposed surface of the emitter was passivated by a thin (approximately 50A) P-rich oxide. Based on the measured EQY and J(sub sc)-V(sub oc) characteristics of our experimental high V(sub oc) p(+)n InP solar cells, we project that reducing the emitter thickness to 0.3 microns, using an optimized AR coating, maintaining the surface hole concentration of 3 x 10(exp 18)cm(sup -3), reducing the grid shadowing from actual 10.55 percent to 6 percent and reducing the contact resistance will increase the actual measured 12.57 percent AMO 25 C efficiency to about 20.1 percent. By using our state-of-the-art p(+)n structures which have a surface hole concentration of 4 x 10(exp 18)cm(sup -3) and slightly improving the front surface passivation, an even higher practically achievable AMO, 25 C efficiency of 21.3 percent is projected.

Flood, D. J.↗
DOE OSTI2023

Different higher order kinematics between star-forming and quiescent galaxies based on the SAMI, MAGPI, and LEGA-C surveys

We present the first statistical study of spatially integrated non-Gaussian stellar kinematics spanning 7 Gyr in cosmic time. We use deep, rest-frame optical spectroscopy of massive galaxies (stellar mass $M_\star \gt 10^{10.5} \, \mathrm{M_\odot }$) at redshifts z = 0.05, 0.3, and 0.8 from the SAMI, MAGPI, and LEGA-C surveys, to measure the excess kurtosis h 4 of the stellar velocity distribution, the latter parametrized as a Gauss–Hermite series. We find that at all redshifts where we have large enough samples, h 4 anticorrelates with the ratio between rotation and dispersion, highlighting the physical connection between these two kinematic observables. In addition, and independently from the anticorrelation with rotation-to-dispersion ratio, we also find a correlation between h 4 and M ⋆ , potentially connected to the assembly history of galaxies. In contrast, after controlling for mass, we find no evidence of independent correlation between h 4 and aperture velocity dispersion or galaxy size. These results hold for both star-forming and quiescent galaxies. For quiescent galaxies, h 4 also correlates with projected shape, even after controlling for the rotation-to-dispersion ratio. At any given redshift, star-forming galaxies have lower h 4 compared to quiescent galaxies, highlighting the link between kinematic structure and star-forming activity.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on YMg14CdO16 by Materials Project

Mg14YCdO16 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are four inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, corners with two equivalent CdO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.02–2.20 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.08–2.31 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are one shorter (2.18 Å) and five longer (2.21 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one YO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–13°. There are a spread of Mg–O bond distances ranging from 2.15–2.25 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.20 Å) and four longer (2.25 Å) Y–O bond lengths. Cd is bonded to six O atoms to form CdO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.20 Å) and four longer (2.37 Å) Cd–O bond lengths. There are nine inequivalent O sites. In the first O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to five Mg and one Cd atom to form a mixture of edge and corner-sharing OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–8°. Both O–Mg bond lengths are 2.21 Å. In the third O site, O is bonded to five Mg and one Cd atom to form a mixture of edge and corner-sharing OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are two shorter (2.15 Å) and two longer (2.21 Å) O–Mg bond lengths. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. In the fifth O site, O is bonded to four equivalent Mg and two equivalent Y atoms to form OY2Mg4 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to four equivalent Mg and two equivalent Cd atoms to form OMg4Cd2 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to five Mg and one Cd atom to form a mixture of edge and corner-sharing OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–8°. The O–Mg bond length is 2.02 Å. In the ninth O site, O is bonded to five Mg and one Cd atom to form a mixture of edge and corner-sharing OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of O–Mg bond distances ranging from 2.02–2.21 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr5Cd5P6(O12F)2 by Materials Project

Sr5Cd5P6(O12F)2 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are five inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Sr–O bond distances ranging from 2.41–2.92 Å. The Sr–F bond length is 2.39 Å. In the second Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Sr–O bond distances ranging from 2.42–2.95 Å. The Sr–F bond length is 2.39 Å. In the third Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Sr–O bond distances ranging from 2.41–2.95 Å. The Sr–F bond length is 2.38 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Sr–O bond distances ranging from 2.42–2.94 Å. The Sr–F bond length is 2.45 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to six O2- and one F1- atom. There are a spread of Sr–O bond distances ranging from 2.41–2.92 Å. The Sr–F bond length is 2.47 Å. There are three inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to five O2- and one F1- atom. There are a spread of Cd–O bond distances ranging from 2.31–2.51 Å. The Cd–F bond length is 2.27 Å. In the second Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.41–2.52 Å. In the third Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.40–2.46 Å. There are six inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. In the second P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.56 Å) and two longer (1.57 Å) P–O bond length. In the third P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. In the fourth P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.54–1.58 Å. In the fifth P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. In the sixth P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.54 Å) and two longer (1.57 Å) P–O bond length. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded to one Sr2+, two equivalent Cd2+, and one P5+ atom to form distorted edge-sharing OSrCd2P tetrahedra. In the second O2- site, O2- is bonded to one Sr2+, two equivalent Cd2+, and one P5+ atom to form distorted edge-sharing OSrCd2P tetrahedra. In the third O2- site, O2- is bonded to one Sr2+, two equivalent Cd2+, and one P5+ atom to form distorted edge-sharing OSrCd2P tetrahedra. In the fourth O2- site, O2- is bonded to one Sr2+, two equivalent Cd2+, and one P5+ atom to form distorted edge-sharing OSrCd2P tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Cd2+ and one P5+ atom. In the sixth O2- site, O2- is bonded to one Sr2+, two equivalent Cd2+, and one P5+ atom to form distorted edge-sharing OSrCd2P tetrahedra. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, two equivalent Cd2+, and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+, two equivalent Cd2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+, two equivalent Cd2+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Cd2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+, two equivalent Cd2+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one Sr2+, two equivalent Cd2+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, one Cd2+, and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the sixteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to two Sr2+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Sr2+, one Cd2+, and one P5+ atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a trigonal planar geometry to three Sr2+ atoms. In the second F1- site, F1- is bonded in a trigonal planar geometry to two Sr2+ and one Cd2+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2017

An Experimental Study and Database for Tip Vortex Flow From an Airfoil

An experimental investigation of tip vortices from a NACA0012 airfoil is conducted in a low-speed wind tunnel at a chord Reynolds number (Rc) of 4×10(exp 4 ). Data for the stationary airfoil at various angles of attack (alpha) are first discussed. Detailed flow-field surveys are done for two cases: alpha = 10deg with attached flow and alpha = 25deg with massive flow separation. Data include mean velocity, streamwise vorticity, and turbulent stresses at various streamwise locations. For all cases, the vortex core is seen to involve a mean velocity deficit. The deficits in these cases trace to the airfoil wake, part of which gets wrapped up by the tip vortex. Comparison with data from the literature suggests that with increasing Rc, the deficit turns into an excess, with the transition occurring in the approximate Rc range of 2×10(exp 5) to 5×10(exp 5). Survey results for various shapes of the airfoil wingtip are then presented. The shapes include square and rounded ends and a number of winglet designs. Finally, data under sinusoidal pitching condition, for the airfoil with square ends, are documented. All pitching cases pertain to a mean alpha = 15deg, while the amplitude and frequency are varied. Amplitudes of +/-5deg, +/-10deg, and +/-15deg and reduced frequencies k = 0.08, 0.2, and 0.33 are covered. Digital records of all data and some of the hardware design are made available on a supplemental CD with the electronic version of the paper for those interested in numerical simulation.

turbulence↗
NASA NTRS1992

UIT support observations archive

We are in the process of archiving the approximately 1.2Tbytes of imaging data acquired in support of UIT observations. The UIT is one of three telescopes comprising the ASTRO spacecraft and is a 38-cm f/9 Ritchey-Chretien telescope with wavelength coverage 1200 A to 3000 A and a 40 arcminute diameter field-of-view at 4 min FWHM resolution. During the ASTRO shuttle mission, there were 65 different pointings (some with multiple targets) of the UIT and hence 65 fields. Our support data of these fields were obtained with the KPNO and CTIO 0.9m telescopes and several of the 2048x2048 CCD's. Our images are typically about 20 acrminutes on a side and contain the entire UV target except for nearby galaxies, for which mosaiced images were created. All good quality images in the broadband and narrow band filters for every target are being archived. Though all of the UIT targets were well studied astronomical objects, these frames are many of the first large field format images of them and, when combined with the soon to be released UV frames, provide a unique dataset. These data were already used to address a wide variety of astronomical questions. Vacuum ultraviolet (VUV) observations were used to study star formation in a sample of nearby galaxies, since integrated VUV - optical colors provide the most sensitive available measure of the formation rate of massive stars. The blue stages later in stellar evolution are also being studied. These data allow more accurate determination of the helium and metallicities of hothorzontal branch stars. These data are being prepared to release to the public in CD-ROM format through the National Space Science Data Center.

Smith, Eric P.↗
DOE OSTI2020

Materials Data on YMg30CdO32 by Materials Project

Mg30YCdO32 is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.08–2.18 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.01 Å) and four longer (2.19 Å) Mg–O bond lengths. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.15 Å) and two longer (2.16 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.14 Å) and two longer (2.18 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one YO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.09–2.24 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of Mg–O bond distances ranging from 2.15–2.18 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one YO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are a spread of Mg–O bond distances ranging from 2.11–2.22 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–7°. There are a spread of Mg–O bond distances ranging from 2.14–2.19 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.15 Å) and four longer (2.25 Å) Y–O bond lengths. Cd is bonded to six O atoms to form CdO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.20 Å) and four longer (2.32 Å) Cd–O bond lengths. There are twelve inequivalent O sites. In the first O site, O is bonded to five Mg and one Y atom to form a mixture of edge and corner-sharing OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the third O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the fourth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. Both O–Mg bond lengths are 2.16 Å. In the fifth O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.13 Å) and two longer (2.19 Å) O–Mg bond lengths. In the sixth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are two shorter (2.14 Å) and two longer (2.16 Å) O–Mg bond lengths. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 1–5°. In the eighth O site, O is bonded to four equivalent Mg, one Y, and one Cd atom to form OYMg4Cd octahedra that share corners with six OYMg4Cd octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OYMg4Cd octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the tenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. The O–Mg bond length is 2.19 Å. In the twelfth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg6 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are a spread of O–Mg bond distances ranging from 2.14–2.19 Å.

36 MATERIALS SCIENCE↗
NASA NTRS2004

Comparisons of the Solutions for the Category 3--Problem 2: Cascade-Gust Interaction

Six different solutions were submitted for this benchmark problem. These were obtained using a variety of methods that can be conveniently categorized in two main groups, a nonlinear time-domain group and a linearized frequency-domain group. The first includes solutions submitted by (1) Hixon, (2) Nallasamy et. al, (3) Shieh et. al, and (4) Wang et. al, and the second includes solutions submitted by (5) Coupland and (6) Serrano et. al. Methods (1) and (2) use sixth order compact differencing schemes and the rest are essentially second order in space. With the exception of the solution submitted by Shieh et. al, all are individually discussed in great detail in the workshop proceedings. Comparisons of the submitted solutions with the benchmark solution are presented below. Due to differences in the level of solution detail provided to the author by the participants, the comparisons do not always include results from all submissions. It should be noted at the outset that, since the benchmark solution itself was numerically computed, the comparisons are somewhat subjective. In order to provide maximum latitude for the participants of the workshop, no restrictions were placed on the type of method that could be used to solve the problem. Neither was there were any stipulations to use a particular grid topology or grid density. Therefore, without a detailed study of the critical features of the computed solutions, it is not possible to make concrete statements about the relative merits of one method over another. Such a study is beyond the scope of the current exercise, especially since complete flowfield details were not provided to the author by all participants. Instead a package, containing the information about the benchmark solution (both the steady and unsteady parts of it), is included on the proceedings CD should the authors who submitted solutions for this problem wish to examine in detail the benchmark solution and compare their results to it.

Envia, Edmane↗
NASA NTRS1992

Late quaternary time series of Arabian Sea productivity: Global and regional signals

Modern annual floral and faunal production in the northwest Arabian Sea derives primarily from upwelling induced by strong southwest winds during June, July, and August. Indian Ocean summer monsoon winds are, in turn, driven by differential heating between the Asian continent and the Indian ocean to the south. This differential heating produces a strong pressure gradient resulting in southwest monsoon winds and both coastal and divergent upwelling off the Arabian Peninsula. Over geologic time scales (10(exp 4) to 10(exp 6) years), monsoon wind strength is sensitive to changes in boundary conditions which influence this pressure gradient. Important boundary conditions include the seasonal distribution of solar radiation, global ice volume, Indian Ocean sea surface temperature, and the elevation and albedo of the Asian continent. To the extent that these factors influence monsoon wind strength, they also influence upwelling and productivity. In addition, however, productivity associated with upwelling can be decoupled from the strength of the summer monsoon winds via ocean mechanisms which serve to inhibit or enhance the nutrient supply in the intermediate waters of the Indian Ocean, the source for upwelled waters in the Arabian Sea. To differentiate productivity associated with wind-induced upwelling from that associated with other components of the system such as nutrient sequestering in glacial-age deep waters, we employ a strategy which monitors independent components of the oceanic and atmospheric subsystems. Using sediment records from the Owen Ridge, northwest Arabian Sea, we monitor the strength of upwelling and productivity using two independent indicators, percent G. bulloides and opal accumulation. We monitor the strength of southwest monsoon winds by measuring the grain-size of lithogenic dust particles blown into the Arabian Sea from the surrounding deserts of the Somali and Arabian Peninsulas. Our current hypothesis is that the variability associated with the 41 kyr power in the G. bulloides and opal accumulation records derive from nutrient availability in the intermediate waters which are upwelled via monsoon winds. This hypothesis is testable by comparison with Cd records of intermediate and deep waters of the Atlantic and Indian Ocean.

Clemens, Steven C.↗
NASA NTRS1992

Stimulation of nodulation in field peas (Pisum sativum) by low concentrations of ammonium in hydroponic culture

Although the inhibitory effects of high concentrations of mineral N (> 1.0 mM) on nodule development and function have often been studied, the effects of low, static concentrations of NH4+ (< 1.0 mM) on nodulation are unknown. In the present experiments we examine the effects of static concentrations of NH4+ at 0, 0.1 and 0.5 mM in flowing, hydroponic culture on nodule establishment and nitrogenase activity in field peas [Pisum sativum L. cv. Express (Svalof AB)] for the initial 28 days after planting (DAP). Peas grown in the presence of low concentrations of NH4+ had significantly greater nodule numbers (up to 4-fold) than plants grown without NH4+. Nodule dry weight per plant was significantly higher at 14, 21 and 28 DAP in plants grown in the presence of NH4+, but individual nodule mass was lower than in plants grown without NH4+. The nodulation pattern of the plants supplied with NH4+ was similar to that often reported for supernodulating mutants, however the plants did not express other growth habits associated with supernodulation. Estimates of N2 fixation indicate that the plus-NH4+ peas fixed as much or more N2 than the plants supplied with minus-NH4+ nutrient solution. There were no significant differences in nodule numbers, nodule mass or NH4+ uptake between the plants grown at the two concentrations of NH4+. Nodulation appeared to autoregulate by 14 DAP in the minus-NH4+ treatment. Plant growth and N accumulation in the minus-NH4+ plants lagged behind those of the plus-NH4+ treatments prior to N2 fixation becoming well established in the final week of the experiment. The plus-NH4+ treatments appeared not to elicit autoregulation and plants continued to initiate nodules throughout the experiment.

NASA Program CELSS↗
DOE OSTI2020

Materials Data on Cd9(InSe2)20 by Materials Project

Cd9(InSe2)20 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are nine inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form distorted CdSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with three InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.64–3.17 Å. In the second Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form distorted CdSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with four InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.63–3.28 Å. In the third Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form distorted CdSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with three InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.64–3.17 Å. In the fourth Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form CdSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with two InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.74–2.87 Å. In the fifth Cd2+ site, Cd2+ is bonded in a 5-coordinate geometry to five Se+1.85- atoms. There are a spread of Cd–Se bond distances ranging from 2.63–3.35 Å. In the sixth Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form CdSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with four InSe5 trigonal bipyramids, and edges with three InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.71–2.88 Å. In the seventh Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form CdSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with four InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.73–2.87 Å. In the eighth Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form CdSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with four InSe5 trigonal bipyramids, and edges with three InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.69–2.89 Å. In the ninth Cd2+ site, Cd2+ is bonded to five Se+1.85- atoms to form CdSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with four InSe5 trigonal bipyramids, and edges with four InSe5 trigonal bipyramids. There are a spread of Cd–Se bond distances ranging from 2.72–2.88 Å. There are twenty inequivalent In+2.80+ sites. In the first In+2.80+ site, In+2.80+ is bonded in a 5-coordinate geometry to five Se+1.85- atoms. There are a spread of In–Se bond distances ranging from 2.66–3.30 Å. In the second In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with eight InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.64–3.06 Å. In the third In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.65–3.13 Å. In the fourth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.65–3.05 Å. In the fifth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.67–3.09 Å. In the sixth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.65–3.06 Å. In the seventh In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with eight InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.66–3.04 Å. In the eighth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.65–3.06 Å. In the ninth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with eight InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.66–3.02 Å. In the tenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.62–3.11 Å. In the eleventh In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.66–3.07 Å. In the twelfth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.63–3.03 Å. In the thirteenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.65–2.99 Å. In the fourteenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.65–3.02 Å. In the fifteenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.66–3.00 Å. In the sixteenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share a cornercorner with one CdSe5 trigonal bipyramid, corners with seven InSe5 trigonal bipyramids, and edges with two CdSe5 trigonal bipyramids. There are a spread of In–Se bond distances ranging from 2.66–3.01 Å. In the seventeenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with eight InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.65–3.09 Å. In the eighteenth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with eight InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.66–3.09 Å. In the nineteenth In+2.80+ site, In+2.80+ is bonded in a 5-coordinate geometry to five Se+1.85- atoms. There are a spread of In–Se bond distances ranging from 2.66–3.28 Å. In the twentieth In+2.80+ site, In+2.80+ is bonded to five Se+1.85- atoms to form distorted InSe5 trigonal bipyramids that share corners with two CdSe5 trigonal bipyramids, corners with six InSe5 trigonal bipyramids, and an edgeedge with one CdSe5 trigonal bipyramid. There are a spread of In–Se bond distances ranging from 2.65–3.02 Å. There are forty inequivalent Se+1.85- sites. In the first Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share a cornercorner with one SeCd2In2 tetrahedra and corners with four SeCdIn3 trigonal pyramids. In the second Se+1.85- site, Se+1.85- is bonded in a 4-coordinate geometry to one Cd2+ and three In+2.80+ atoms. In the third Se+1.85- site, Se+1.85- is bonded in a distorted trigonal non-coplanar geometry to one Cd2+ and two In+2.80+ atoms. In the fourth Se+1.85- site, Se+1.85- is bonded in a 3-coordinate geometry to three In+2.80+ atoms. In the fifth Se+1.85- site, Se+1.85- is bonded in a distorted trigonal non-coplanar geometry to one Cd2+ and two In+2.80+ atoms. In the sixth Se+1.85- site, Se+1.85- is bonded in a 4-coordinate geometry to one Cd2+ and three In+2.80+ atoms. In the seventh Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share a cornercorner with one SeCd2In2 tetrahedra, corners with six SeCdIn3 trigonal pyramids, and an edgeedge with one SeCd2In2 tetrahedra. In the eighth Se+1.85- site, Se+1.85- is bonded in a 4-coordinate geometry to two Cd2+ and two In+2.80+ atoms. In the ninth Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share corners with two SeCd2In2 tetrahedra and corners with six SeCdIn3 trigonal pyramids. In the tenth Se+1.85- site, Se+1.85- is bonded to two Cd2+ and two In+2.80+ atoms to form a mixture of edge and corner-sharing SeCd2In2 tetrahedra. In the eleventh Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share a cornercorner with one SeCd2In2 tetrahedra, corners with six SeCdIn3 trigonal pyramids, and an edgeedge with one SeCd2In2 tetrahedra. In the twelfth Se+1.85- site, Se+1.85- is bonded in a distorted trigonal non-coplanar geometry to one Cd2+ and two In+2.80+ atoms. In the thirteenth Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share corners with two SeCd2In2 tetrahedra and corners with six SeCdIn3 trigonal pyramids. In the fourteenth Se+1.85- site, Se+1.85- is bonded in a distorted T-shaped geometry to one Cd2+ and two In+2.80+ atoms. In the fifteenth Se+1.85- site, Se+1.85- is bonded to one Cd2+ and three In+2.80+ atoms to form distorted SeCdIn3 trigonal pyramids that share a cornercorner with one SeCd2In2 tetrahedra, corners with seven SeCdIn3 trigonal pyramids, and an edgeedge with one SeCd2In2 tetrahedra. In the sixteenth Se+1.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg14AlCdO16 by Materials Project

Mg14CdAlO16 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are nine inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent AlO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.09–2.27 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.97–2.23 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–16°. There are a spread of Mg–O bond distances ranging from 2.14–2.18 Å. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.15–2.17 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Mg–O bond distances ranging from 2.14–2.17 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.12–2.21 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of Mg–O bond distances ranging from 2.14–2.17 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.12–2.21 Å. In the ninth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one CdO6 octahedra, an edgeedge with one AlO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 2–17°. There are a spread of Mg–O bond distances ranging from 2.14–2.22 Å. Cd is bonded to six O atoms to form CdO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent CdO6 octahedra, corners with two equivalent AlO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Cd–O bond distances ranging from 2.16–2.49 Å. Al is bonded to six O atoms to form AlO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent CdO6 octahedra, corners with two equivalent AlO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Al–O bond distances ranging from 1.83–2.16 Å. There are eleven inequivalent O sites. In the first O site, O is bonded to five Mg and one Al atom to form OMg5Al octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the third O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OMg5Al octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. Both O–Mg bond lengths are 2.16 Å. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fifth O site, O is bonded to four Mg and two equivalent Al atoms to form OMg4Al2 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to four Mg and two equivalent Cd atoms to form OMg4Cd2 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4Al2 octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4Cd2 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the ninth O site, O is bonded to four Mg, one Cd, and one Al atom to form distorted OMg4AlCd octahedra that share corners with six OMg4AlCd octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–16°. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4AlCd octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–11°. In the eleventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4AlCd octahedra and edges with twelve OMg5Al octahedra. The corner-sharing octahedra tilt angles range from 0–11°. There are two shorter (2.14 Å) and two longer (2.16 Å) O–Mg bond lengths.

36 MATERIALS SCIENCE↗
NASA NTRS1986

Utilization of ammonium as a nitrogen source: effects of ambient acidity on growth and nitrogen accumulation by soybean

Dry matter accumulation of plants utilizing NH4+ as the sole nitrogen source generally is less than that of plants receiving NO3- unless acidity of the root-zone is controlled at a pH of about 6.0. To test the hypothesis that the reduction in growth is a consequence of nitrogen stress within the plant in response to effects of increased acidity during uptake of NH4+ by roots, nonnodulated soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 24 days in flowing nutrient culture containing 1.0 millimolar NH4+ as the nitrogen source. Acidities of the culture solutions were controlled at pH 6.1, 5.1, and 4.1 +/- 0.1 by automatic additions of 0.01 N H2SO4 or Ca(OH)2. Plants were sampled at intervals of 3 to 4 days for determination of dry matter and nitrogen accumulation. Rates of NH4+ uptake per gram root dry weight were calculated from these data. Net CO2 exchange rates per unit leaf area were measured on attached leaves by infrared gas analysis. When acidity of the culture solution was increased from pH 6.1 to 5.1, dry matter and nitrogen accumulation were reduced by about 40% within 14 days. Net CO2 exchange rates per unit leaf area, however, were not affected, and the decreased growth was associated with a reduction in rates of appearance and expansion of new leaves. The uptake rates of NH4+ per gram root were about 25% lower throughout the 24 days at pH 5.1 than at 6.1. A further increase in solution acidity from pH 5.1 to 4.1 resulted in cessation of net dry matter production and appearance of new leaves within 10 days. Net CO2 exchange rates per unit leaf area declined rapidly until all viable leaves had abscised by 18 days. Uptake rates of NH4+, which were initially about 50% lower at pH 4.1 than at 6.1 continued to decline with time of exposure until net uptake ceased at 10 days. Since these responses also are characteristic of the sequence of responses that occur during onset and progression of a nitrogen stress, they corroborate our hypothesis.

NASA Discipline Number 61-10↗
NASA NTRS1990

Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

NASA Discipline Life Support Systems↗
DOE OSTI2026

DESI DR2 Galaxy luminosity functions

We present galaxy luminosity functions (LFs) for the Dark Energy Spectroscopic Instrument (DESI) DR2 Bright Galaxy Survey (BGS) in the g, r, z, and $w1$ bands over $0.002\lt z\lt 0.6$. Our analysis uses updated k-corrections and evolutionary corrections, including new polynomial kcorrection fits derived from BGS Year 1 data that supersede earlier GAMA-based prescriptions. Exploiting the statistical power of DESI, we measure LFs to very faint magnitudes, reaching $^{0.1}M_r-5\log h\sim -10$. Independent measurements from the North and South survey regions show excellent agreement around the LF knee, but the very small statistical uncertainties reveal that simple analytic forms fail to capture the full LF shape. The bright end departs from a pure exponential decline, while the faint end exhibits complex, non-powerlaw behaviour, including a pronounced upturn at $^{0.1}M_r-5\log h\gtrsim -15$, which is stronger for red galaxies than for blue. We show that our LFs are largely complete for galaxies with surface brightness $\mu _{50}\lt 25$, and that an apparent steepening fainter than $-13$ is driven primarily by local overdensity and fragmentation of large galaxies. A systematic North–South offset at the brightest magnitudes is traced to red galaxies and may reflect shallower North photometry underestimating extended earlytype profiles, although this remains inconclusive. We therefore also provide LFs based on model Petrosian magnitudes. Redshift splitting reveals small but significant residuals, indicating limitations of a simple global evolutionary model. Using the redshift limits of J. Loveday et al. (2012), we find excellent agreement with GAMA, with substantially reduced statistical errors. These measurements provide a precise reference for studies of environmental and population-dependent LFs and for testing galaxy formation models.

79 ASTRONOMY AND ASTROPHYSICS↗