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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.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Structure of the Polymer Backbones in polyMOF Materials

The molecular connectivity of polymer–metal–organic framework (polyMOF) hybrid materials was investigated using density functional theory calculations and solid-state NMR spectroscopy. The architectural constraints that dictate the formation of polyMOFs were assessed by examining poly(1,4-benzenedicarboxylic acid) (pbdc) polymers in two archetypical MOF lattices (UiO-66 and IRMOF-1). Modeling of the polyMOFs showed that in the IRMOF-1-type lattice, six, seven, and eight methylene (–CH 2 –) groups between 1,4-benzenedicarboxylate (terephthalate, bdc 2– ) units can be accommodated without significant distortions, while in the UiO-66-type lattice, an optimal spacing of seven methylene groups between bdc 2– units is needed to minimize strain. Solid-state NMR supports these predictions and reveals pronounced spectral differences for the same polymer in the two polyMOF lattices. With seven methylene groups, polyUiO-66-7a shows 7 ± 3% of uncoordinated terephthalate linkers, while these are undetectable (<4%) in the corresponding polyIRMOF-1-7a. Additionally, NMR-detected backbone mobility is significantly higher in the polyIRMOF-1-7a than in the corresponding polyUiO-66-7a, again indicative of taut chains in the latter.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

The solution structures and relative stability constants of lanthanide–EDTA complexes predicted from computation

Ligand selectivity to specific lanthanide (Ln) ions is key to the separation of rare earth elements from each other. Ligand selectivity can be quantified with relative stability constants (measured experimentally) or relative binding energies (calculated computationally). The relative stability constants of EDTA (ethylenediaminetetraacetic acid) with La 3+ , Eu 3+ , Gd 3+ , and Lu 3+ were predicted from relative binding energies, which were quantified using electronic structure calculations with relativistic effects and based on the molecular structures of Ln–EDTA complexes in solution from density functional theory molecular dynamics simulations. The protonation state of an EDTA amine group was varied to study pH ~7 and ~11 conditions. Further, simulations at 25 °C and 90 °C were performed to elucidate how structures of Ln–EDTA complexes varying with temperature are related to complex stabilities at different pH conditions. Relative stability trends are predicted from computation for varying Ln 3+ ions (La, Eu, Gd, Lu) with a single ligand (EDTA at pH ~11), as well as for a single Ln 3+ ion (La) with varying ligands (EDTA at pH ~7 and ~11). Changing the protonation state of an EDTA amine site significantly changes the solution structure of the Ln–EDTA complex resulting in a reduction of the complex stability. As a result, increased Ln–ligand complex stability is correlated to reduced structural variations in solution upon an increase in temperature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1974

Monte Carlo analysis of the solar-wind modulation of galactic C-N-O at solar maximum

A previous (Moss and Giuli, 1971) Monte Carlo analysis of the solar-wind modulation of galactic cosmic-ray rigidity spectra is extended to include particles in the C-N-O group. A solar cavity 'radius' of 7 AU is found to be consistent with observations of the C-N-O component at solar maximum. The variation in modulation between solar maximum and solar minimum may be explained solely by variation of the solar cavity size, with no change in the scattering mean free path.

Moss, T. A.↗
NASA NTRS2003

Columbia Accident Investigation Board Report. Volume Five

Volume V of the Report contains appendices that were not cited in VolumeI. These consist of documents produced by NASA and other organizations, which were provided to the Columbia Accident Investigation Board in support of its inquiry into the February 1, 2003 destruction of the Space Shuttle Columbia The contents include:. Appendix G.1 Requirements and Procedures for Certification of Flight Readiness; Appendix G.2 Appendix R, Space Shuttle Program Contingency Action Plan; Appendix G.3 CAIB Charter, with Revisions; Appendix G.4 Group 1 Matrix Brief on Maintenance, Material, and Management; Appendix G.5 Vehicle Data Mapping(VDM) Team Final Report, Jun 13, 2003; Appendix G.6 SRB Working Group Presentation to CAIB; Appendix G. 7 Starfire Team Final Report, Jun 3, 2003; Appendix G.8 Using the Data and Observations from Flight STS-107, Executive Summary; Appendix G.9 Contracts, Incentives, and Safety/Technical Excellence; Appendix G.10 Detailed Summaries: Rogers Commission Report, ASAP Report, SIAT Report; Appendix G.11 Foam Application and Production Chart; Appendix G.12 Crew Survivability Report; and Appendix G.12 Aero/Aerothermal/ Thermal/Structures Team FinalReport, August 6, 2003.

CAIB (COLUMBIA ACCIDENT INVESTIGATION BOARD)↗
NASA NTRS2000

Left ventricular hypertrophy in ascending aortic stenosis mice: anoikis and the progression to early failure

BACKGROUND: To determine potential mechanisms of the transition from hypertrophy to very early failure, we examined apoptosis in a model of ascending aortic stenosis (AS) in male FVB/n mice. METHODS AND RESULTS: Compared with age-matched controls, 4-week and 7-week AS animals (n=12 to 16 per group) had increased ratios of left ventricular weight to body weight (4.7+/-0.7 versus 3.1+/-0.2 and 5. 7+/-0.4 versus 2.7+/-0.1 mg/g, respectively, P<0.05) with similar body weights. Myocyte width was also increased in 4-week and 7-week AS mice compared with controls (19.0+/-0.8 and 25.2+/-1.8 versus 14. 1+/-0.5 microm, respectively, P<0.01). By 7 weeks, AS myocytes displayed branching with distinct differences in intercalated disk size and staining for beta(1)-integrin on both cell surface and adjacent extracellular matrix. In vivo left ventricular systolic developed pressure per gram as well as endocardial fractional shortening were similar in 4-week AS and controls but depressed in 7-week AS mice. Myocyte apoptosis estimated by in situ nick end-labeling (TUNEL) was extremely rare in 4-week AS and control mice; however, a low prevalence of TUNEL-positive myocytes and DNA laddering were detected in 7-week AS mice. The specificity of TUNEL labeling was confirmed by in situ ligation of hairpin oligonucleotides. CONCLUSIONS: Our findings indicate that myocyte apoptosis develops during the transition from hypertrophy to early failure in mice with chronic biomechanical stress and support the hypothesis that the disruption of normal myocyte anchorage to adjacent extracellular matrix and cells, a process called anoikis, may signal apoptosis.

NASA Discipline Cardiopulmonary↗
NASA NTRS2006

Markers of bone resorption and calcium metabolism are related to dietary intake patterns in male and female bed rest subjects

Dietary potassium and protein intakes predict net endogenous acid production in humans. Intracellular buffers, including exchangeable bone mineral, play a crucial role in balancing chronic acid-base perturbations in the body; subsequently, chronic acid loads can potentially contribute to bone loss. Bone is lost during space flight, and a dietary countermeasure would be desirable for many reasons. We studied the ability of diet protein and potassium to predict levels of bone resorption markers in males and females. Identical twin pairs (8 M, 7 F) were assigned to 2 groups: bed rest (sedentary, SED) or bed rest with supine treadmill exercise in a lower body negative pressure chamber (EX). Diet was controlled for 3 d before and 30 d of bed rest (BR). Urinary Ca, N-telopeptide (NTX), and pyridinium crosslinks (PYD) were measured before and on days 5, 12, 19, and 26 of BR. Data were analyzed by Pearson correlation (P<0.05). The ratio of dietary animal protein/potassium intake was not correlated with NTX before BR for males or females, but they were positively correlated in both groups of males during bed rest. Dietary animal protein/potassium and urine Ca were correlated before and during bed rest for the males, and only during bed rest for the females. Conversely, the ratio of dietary vegetable protein/potassium intake was negatively correlated with urinary calcium during bed rest for the females, but there was no relationship between vegetable protein/potassium intake and bone markers for the males. These data suggest that the ratio of animal protein/potassium intake may affect bone, particularly in bed rest subjects. These data show that the type of protein and gender may be additional factors that modulate the effect of diet on bone metabolism during bed rest. Altering this ratio may help prevent bone loss on Earth and during space flight.

Smith, Scott M.↗
NASA NTRS2022

Aquatic Primary Productivity Field Protocols for Satellite Validation and Model Synthesis

In 2018, a working group sponsored by the NASA Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) project, in conjunction with the International Ocean Colour Coordinating Group (IOCCG), European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), and Japan Aerospace Exploration Agency (JAXA), was assembled with the aim to develop community consensus on multiple methods for measuring aquatic primary productivity used for satellite validation and model synthesis. A workshop to commence the working group efforts was held December 5–7, 2018, at the University Space Research Association headquarters in Columbia, MD, USA, bringing together 26 active researchers from 16 institutions. In this document, we discuss and develop the workshop findings as they pertain to primary productivity measurements, including the essential issues, nuances, definitions, scales, uncertainties, and ultimately best practices for data collection across multiple methodologies.

ocean color↗
NASA NTRS1975

The application of Skylab altimetry to marine geoid determination

The author had identified the following significant results. The major results can be divided broadly into two groups. One group is concerned with the effects of errors inherent in the various input data, such as the orbit emphemeris, a priori geoid etc. The other consists of the results of the actual analysis of the data from the Skylab EREP passes 4, 6, 7, and 9. Results from the first group were obtained from the analysis of some preliminary data from EREP pass 9 mode 5. The second group of results consists of a set of recovered bias terms for each of the submodes of observations and a set of nine altimetry geoid profiles corresponding to the various passes and modes. Along with each of these profiles, the a priori geoid, gravity anomaly, and the bathymetric data profiles are also presented for easy comparison.

Mourad, A. G.↗
DOE OSTI2020

Materials Data on LiCa9Co(PO4)7 by Materials Project

LiCa9Co(PO4)7 crystallizes in the trigonal R3c space group. The structure is three-dimensional. Li1+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All Li–O bond lengths are 2.26 Å. There are three inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.89 Å. In the second Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.41–2.76 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.72 Å. Co2+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (2.11 Å) and three longer (2.12 Å) Co–O bond lengths. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CoO6 octahedra. The corner-sharing octahedral tilt angles are 52°. There is three shorter (1.55 Å) and one longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CoO6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of P–O bond distances ranging from 1.54–1.58 Å. In the third P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.55 Å) and one longer (1.56 Å) P–O bond length. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Ca2+, one Co2+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Li1+, two Ca2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three Ca2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Ca2+, one Co2+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2B12H26O7 by Materials Project

Li2(H2O)7(BH)12 crystallizes in the orthorhombic Cmcm space group. The structure is zero-dimensional and consists of forty-eight boranediylradical molecules and four Li2(H2O)7 clusters. In each Li2(H2O)7 cluster, Li1+ is bonded to four O2- atoms to form corner-sharing LiO4 tetrahedra. There are a spread of Li–O bond distances ranging from 1.94–2.05 Å. There are four inequivalent H+0.92+ sites. In the first H+0.92+ site, H+0.92+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H+0.92+ site, H+0.92+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the third H+0.92+ site, H+0.92+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H+0.92+ site, H+0.92+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted tetrahedral geometry to two equivalent Li1+ and two equivalent H+0.92+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two equivalent H+0.92+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Li1+ and two H+0.92+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr8(BCl)7 by Materials Project

Pr8(BCl)7 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are eight inequivalent Pr+3.50+ sites. In the first Pr+3.50+ site, Pr+3.50+ is bonded in a 7-coordinate geometry to five B3- and four Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.61–3.01 Å. There are a spread of Pr–Cl bond distances ranging from 2.92–3.26 Å. In the second Pr+3.50+ site, Pr+3.50+ is bonded in a 7-coordinate geometry to five B3- and four Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.62–3.00 Å. There are a spread of Pr–Cl bond distances ranging from 2.91–3.26 Å. In the third Pr+3.50+ site, Pr+3.50+ is bonded to one B3- and five Cl1- atoms to form distorted PrBCl5 pentagonal pyramids that share corners with two BPr4B3 pentagonal bipyramids and an edgeedge with one PrBCl5 pentagonal pyramid. The Pr–B bond length is 2.66 Å. There are a spread of Pr–Cl bond distances ranging from 2.88–3.03 Å. In the fourth Pr+3.50+ site, Pr+3.50+ is bonded in a 6-coordinate geometry to one B3- and five Cl1- atoms. The Pr–B bond length is 2.49 Å. There are a spread of Pr–Cl bond distances ranging from 2.88–3.03 Å. In the fifth Pr+3.50+ site, Pr+3.50+ is bonded in a 9-coordinate geometry to five B3- and four Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.63–2.94 Å. There are a spread of Pr–Cl bond distances ranging from 3.13–3.28 Å. In the sixth Pr+3.50+ site, Pr+3.50+ is bonded in a 9-coordinate geometry to six B3- and three Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.71–2.74 Å. There are one shorter (2.97 Å) and two longer (3.06 Å) Pr–Cl bond lengths. In the seventh Pr+3.50+ site, Pr+3.50+ is bonded in a 7-coordinate geometry to eight B3- and three Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.70–3.06 Å. There are one shorter (2.96 Å) and two longer (3.15 Å) Pr–Cl bond lengths. In the eighth Pr+3.50+ site, Pr+3.50+ is bonded in a 9-coordinate geometry to five B3- and four Cl1- atoms. There are a spread of Pr–B bond distances ranging from 2.63–2.93 Å. There are a spread of Pr–Cl bond distances ranging from 3.13–3.35 Å. There are seven inequivalent B3- sites. In the first B3- site, B3- is bonded in a 5-coordinate geometry to six Pr+3.50+ and three B3- atoms. There are a spread of B–B bond distances ranging from 1.68–1.96 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to six Pr+3.50+ and three B3- atoms. There is one shorter (1.68 Å) and one longer (1.90 Å) B–B bond length. In the third B3- site, B3- is bonded to four Pr+3.50+ and three B3- atoms to form distorted BPr4B3 pentagonal bipyramids that share a cornercorner with one PrBCl5 pentagonal pyramid, an edgeedge with one BPr5B octahedra, edges with two BPr4B3 pentagonal bipyramids, and a faceface with one BPr4B3 pentagonal bipyramid. There is one shorter (1.64 Å) and one longer (1.74 Å) B–B bond length. In the fourth B3- site, B3- is bonded in a 7-coordinate geometry to five Pr+3.50+ and two B3- atoms. The B–B bond length is 1.74 Å. In the fifth B3- site, B3- is bonded to five Pr+3.50+ and one B3- atom to form edge-sharing BPr5B octahedra. The B–B bond length is 1.74 Å. In the sixth B3- site, B3- is bonded in a 3-coordinate geometry to six Pr+3.50+ and three B3- atoms. In the seventh B3- site, B3- is bonded to four Pr+3.50+ and three B3- atoms to form distorted BPr4B3 pentagonal bipyramids that share a cornercorner with one PrBCl5 pentagonal pyramid, an edgeedge with one BPr5B octahedra, edges with two BPr4B3 pentagonal bipyramids, and a faceface with one BPr4B3 pentagonal bipyramid. There are eight inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Pr+3.50+ atoms. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Pr+3.50+ atoms. In the third Cl1- site, Cl1- is bonded in a 3-coordinate geometry to three Pr+3.50+ atoms. In the fourth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Pr+3.50+ atoms. In the fifth Cl1- site, Cl1- is bonded in a 6-coordinate geometry to six Pr+3.50+ atoms. In the sixth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Pr+3.50+ atoms. In the seventh Cl1- site, Cl1- is bonded in a 3-coordinate geometry to three Pr+3.50+ atoms. In the eighth Cl1- site, Cl1- is bonded in a 6-coordinate geometry to six Pr+3.50+ atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2002

Hydrogen Concentrations on C-class Asteroids from Remote Sensing

We present spectroscopic observations of 16 asteroids from 1.9-3.6 microns, collected from the United Kingdom Infrared Telescope (UKIRT) from 1996-2000. Of these 16 asteroids, 11 show some evidence of a 3-micron hydrated mineral absorption feature greater than 2 sigma at 2.9 microns. Using relations first recognized for carbonaceous chondrite powders by Miyamoto and Zolensky (1994) and Sato et al. (1997), we have determined the hydrogen/silicon ratio for these asteroids and calculated their equivalent water contents, assuming all the hydrogen was in water. The asteroids split into two groups, roughly defined as equivalent water contents of greater than approx. 7% (eight asteroids) and less than approx. 3 % (the remaining eight asteroids). This latter group includes some asteroids for which there is a small but statistically significant 3-micron band of non-zero depth. The G-class asteroids in the survey have higher water contents, consistent with CM chondrites. This strengthens the connection between CM chondrites and G asteroids that was proposed by Burbine (1998). We find that the 0.7-micron and 3-micron band depths are correlated for the population of target objects.

Rivkin, A. S.↗
NASA NTRS2006

Derivation of Apollo 14 High-Al Basalts from Distinct Source Regions at Discrete Times: New Constraints

Apollo 14 basalts occur predominantly as clasts in breccias, but represent the oldest volcanic products that were returned from the Moon [1]. These basalts are relatively enriched in Al2O3 (11-16 wt%) compared to other mare basalts (7-11 wt%) and were originally classified into 5 compositional groups [2,3]. Neal et al. [4] proposed that a continuum of compositions existed. These were related through assimilation (of KREEP) and fractional crystallization (AFC). Age data, however, show that at least three volcanic episodes are recorded in the sample collection [1,5,6]. Recent work has demonstrated that there are three, possibly four groups of basalts in the Apollo 14 sample collection that were erupted from different source regions at different times [7]. This conclusion was based upon incompatible trace element (ITE) ratios of elements that should not be fractionated from one another during partial melting (Fig. 1). These groups are defined as Group A (Groups 4 & 5 of [3]), Group B (Groups 1 & 2 of [3]), and Group C (Group 3 of [3]). Basalt 14072 is distinct from Groups A-C.

Neal, C. R.↗
DOE OSTI2020

Materials Data on Re3(SBr)7 by Materials Project

Re3(SBr)7 is alpha La structured and crystallizes in the trigonal P31c space group. The structure is zero-dimensional and consists of four Re3(SBr)7 clusters. Re7+ is bonded to five S2- and two Br1- atoms to form distorted face-sharing ReS5Br2 pentagonal bipyramids. There are a spread of Re–S bond distances ranging from 2.36–2.47 Å. There are one shorter (2.55 Å) and one longer (2.57 Å) Re–Br bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Re7+ atoms. In the second S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Re7+ and one S2- atom. The S–S bond length is 2.08 Å. In the third S2- site, S2- is bonded in a 6-coordinate geometry to two equivalent Re7+, one S2-, and one Br1- atom. The S–Br bond length is 2.81 Å. There are three inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a single-bond geometry to one Re7+ atom. In the second Br1- site, Br1- is bonded in a single-bond geometry to one Re7+ atom. In the third Br1- site, Br1- is bonded in a 3-coordinate geometry to three equivalent S2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ca10Ag(PO4)7 by Materials Project

AgCa10(PO4)7 crystallizes in the trigonal R3c space group. The structure is three-dimensional. there are four inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to six O2- atoms to form CaO6 octahedra that share corners with six PO4 tetrahedra. There are three shorter (2.27 Å) and three longer (2.30 Å) Ca–O bond lengths. In the second Ca2+ site, Ca2+ is bonded in a 7-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.35–2.92 Å. In the third Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.34–2.89 Å. In the fourth Ca2+ site, Ca2+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Ca–O bond distances ranging from 2.42–3.02 Å. Ag1+ is bonded in a distorted trigonal planar geometry to three equivalent O2- atoms. All Ag–O bond lengths are 2.47 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. All P–O bond lengths are 1.56 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO6 octahedra. The corner-sharing octahedral tilt angles are 58°. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CaO6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of P–O bond distances ranging from 1.54–1.57 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Ca2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to three Ca2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to two Ca2+, one Ag1+, and one P5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2017

Effects of Acute Exposures to Carbon Dioxide upon Cognitive Functions

Carbon dioxide (CO2) originates from human metabolism and typically remains about 10-fold higher in concentration on the International Space Station (ISS) than at the earth's surface. There have been recurring complaints by crew members of episodes of "mental viscosity" adversely affecting their performance, and there is evidence from the ISS that associates CO2 levels with reports of headaches by crewmembers. Consequently, flight rules have been employed to control CO2 below 3 mm Hg, which is well below the existing Spacecraft Maximum Allowable Concentration (SMAC) of 10 mm Hg for 24-hour exposures, and 5.3 mm Hg for exposures of 7 to 180 days. Headaches, while sometime debilitating themselves, are also symptoms that can provide evidence that physiological defense mechanisms have been breached, and there is evidence that CO2 has effects at levels below the threshold for headaches. This concern appears to be substantiated in reports that CO2 at concentrations below 2 mm Hg substantially reduced some cognitive functions that are associated with the ability to make complex decisions in conditions that are characterized by volatility, uncertainty, complexity, ambiguity, and delayed feedback. These are conditions that could be encountered by crews in off-nominal situations or during the first missions beyond low earth orbit. Therefore, we set out to determine if decision-making under volatile, uncertain, confusing and ambiguous circumstances, where feedback is delayed or absent, is correlated with low levels of CO2 during acute exposures (several hours) in crew-like subjects and to determine if additional cognitive domains are sensitive to concentrations of CO2 at, or below, current ISS levels by using a test battery that is currently available onboard ISS. We enrolled 22 volunteers (8 females, 14 males) between the ages of 30-55 (38.8 +/- 7.0) years whose training and professional experience reflect that of the astronaut corps. Subjects were divided among 4 study groups. Exposures occurred in the 20-foot environmental chamber in Bldg 7 at JSC. Each group was exposed to each of four concentrations of CO2 (600, 1200, 2500, and 5000 ppm), and the exposure order was balanced across the groups which were randomly assigned to 4 possible complete exposure orders. Study participants and investigators were blinded to the exposure order. Each exposure lasted 4 hours and occurred on the same day each week for 4 consecutive weeks. Testing included the Strategic Management Simulation (SMS) methodology and the Cognition battery of psychometric measures that are being utilized aboard the ISS. Subjects participated in a familiarization session one week prior to the start of exposure sessions. Each exposure session followed the schedule noted in Figure 1 below. On the morning of each exposure, subjects completed the Cognition battery in a conference room at indoor ambient CO2 levels. Subjects then entered the exposure chamber and were acclimated to the environment for 15 minutes before completing another round of the Cognition battery. After a 20 minute rest, subject completed the approx.80 minute SMS. Subjects were allowed another 20 minute rest period before completing the final Cognition test battery in the exposure chamber. Subjects then returned to the conference room where they completed one final round of Cognition. Data from both testing methodologies are currently being analyzed and will be presented. Study investigators have not yet been unblinded to the coded exposure concentrations, but preliminary results suggest differences.

Ryder, V. E.↗
DOE OSTI2021

Charge completeness and the massless charge lattice in F-theory models of supergravity

We prove that, for every 6D supergravity theory that has an F-theory description, the property of charge completeness for the connected component of the gauge group (meaning that all charges in the corresponding charge lattice are realized by massive or massless states in the theory) is equivalent to a standard assumption made in F-theory for how geometry encodes the global gauge theory by means of the Mordell-Weil group of the elliptic fibration. This result also holds in 4D F-theory constructions for the parts of the gauge group that come from sections and from 7-branes. We find that in many 6D F-theory models the full charge lattice of the theory is generated by massless charged states; this occurs for each gauge factor where the associated anomaly coefficient satisfies a simple positivity condition. We describe many of the cases where this massless charge sufficiency condition holds, as well as exceptions where the positivity condition fails, and analyze the related global structure of the gauge group and associated Mordell-Weil torsion in explicit F-theory models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2024

Syntheses and crystal structures of four new d 0 transition metal tellurites

Four new d 0 transition metal tellurites, namely InVTeO 6 (1), β-InVTe 2 O 8 (2), FeVTe 2 O 8 (3), and Fe 2 MoTe 2 O 10 (4), were synthesized under hydrothermal conditions, and their crystal structures were determined using single-crystal X-ray diffraction. Compound 1 crystallizes in the noncentrosymmetric space group P2 1 2 1 2 1 (No. 19), with unit cell parameters of a = 5.0759(2) Å, b = 8.5030(3) Å, c = 11.6376(5) Å, V = 502.28(3) Å 3 , and Z = 4, while the other three compounds crystallize in centrosymmetric structures, with space group Cmca and unit cell parameters of a = 7.0633(7) Å, b = 8.962(1) Å, c = 20.162(2) Å, V = 1276.3(2) Å 3 , and Z = 8 for compound 2, space group P2 1 /n and unit cell parameters of a = 7.8901(2) Å, b = 4.9617(1) Å, c = 16.4290(3) Å, β = 93.6198(8)°, V = 641.88(2) Å 3 , and Z = 4 for compound 3, and space group Pnma and unit cell parameters of a = 8.7878(2) Å, b = 6.1327(2) Å, c = 15.2423(4) Å, V = 821.45(4) Å 3 , and Z = 4 for compound 4. Compound 3 adopts a two-dimensional (2D) sheet structure composed of FeO 6 octahedra, VO 4 tetrahedra, and TeO 4 polyhedra. The other three compounds exhibit three-dimensional (3D) framework structures: Compound 1 is built from InO 6 octahedra, VO 4 tetrahedra, TeO 4 polyhedra; Compound 2 consists of InO 6 octahedra, VO 5 square pyramids, and TeO 3 polyhedra; and Compound 4 is composed of FeO 6 octahedra, MoO 6 octahedra, and TeO 3 polyhedra. The band structures, density of states, and electron localization functions of all four compounds were calculated. The vibrational spectra were examined for compounds 1, 2, and 4. Furthermore, powder X-ray diffraction, element analysis, and thermogravimetric analysis were conducted for compound 4.

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