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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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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Structural Assessment of Fluorine, Chlorine, Bromine, Iodine, and Hydroxide Substitutions in Lead Arsenate Apatites (Mimetites)–Pb 5 (AsO 4 ) 3 X

Five lead-arsenate apatites (mimetites)-Pb 5 (AsO 4 ) 3 X—where X denotes fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and hydroxide (OH)—were synthesized via precipitation from aqueous solutions. The crystal structures were determined through Rietveld refinement of powder synchrotron X-ray data. All the compounds crystallized in the hexagonal class symmetry (space group P6 3 /m). The Rietveld refinement indicated that mimetite-Cl, -Br, -I, and -OH had an anion deficiency at position X. Substitution of halogens in a mimetite structure brought about systematic changes in unit-cell parameters, interatomic distances, and metaprism twist angles φ, proportional to the substituted halogen’s ionic radius. Mimetite-OH did not follow the linear correlations determined within the series. Twist angle φ, a useful device for monitoring changes in apatite topology, ranged from 20.34° for mimetite-F to 11.42° for mimetite-I. The geometric method has been proposed for determining the diameter of hexagonal channels hosting halogens in apatites. A comparison of the results with halogenated pyromorphites showed similar systematic trends: the substitutions in mimetites have comparable effect on the interatomic distances as in their phosphorous analogues.

58 GEOSCIENCES↗
DOE OSTI2021

Majorana fermion dark matter in minimally extended left-right symmetric model

We present a minimal extension of the left-right symmetric model based on the gauge group SU(3) c × SU(2) L × SU(2) R × U(1) B–L × U(1) X , in which a vector-like fermion pair ( ζ L and ζ R ) charged under the U(1) B–L × U(1) X symmetry is introduced. Associated with the symmetry breaking of the gauge group SU(2) R × U(1) B–L × U(1) X down to the Standard Model (SM) hypercharge U(1) Y , Majorana masses for ζ L,R are generated and the lightest mass eigenstate plays a role of the dark matter (DM) in our universe by its communication with the SM particles through a new neutral gauge boson “ X ”. We consider various phenomenological constraints of this DM scenario, such as the observed DM relic density, the LHC Run-2 constraints from the search for a narrow resonance, and the perturbativity of the gauge couplings below the Planck scale. Combining all constraints, we identify the allowed parameter region which turns out to be very narrow. A significant portion of the currently allowed parameter region will be tested by the High-Luminosity LHC experiments.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2025

Electron-Donating para -Substituent (X) Enhances the Water Oxidation Activity of the Catalyst Ru(4'-X-terpyridine)(phenanthroline-SO 3 ) +

Recently, our group has developed a Ru-based water oxidation catalyst (WOC) with pendant sulfonate (1, Ru(4'-X-terpyridine)(phenanthroline-SO 3 )OTf (X = H, 1a) that shows high activity under both sacrificial oxidant (CAN, Ce(NH 4 ) 2 (NO 3 ) 6 , Ce IV ) and electrocatalytic conditions, in both acidic and neutral media. Here, we demonstrate that the functionalization of the 4'-X-terpyridine ligand with an electron-donating substituent X = OEt (1b) makes potentials of Ru II /Ru III redox catalysis more negative, whereas when X = NO 2 (1c) and CF 3 (1d), potentials are more positive. For 1b, full conversion of the sacrificial oxidant Ce IV occurred in 0.4 h (7 h for 1a), with an initial rate of 2.07 μmol O 2 s –1 and a turnover frequency of 7.6 s –1 , which is 30-fold faster than that for 1a at [cat] 0 = 20 μM. Under electrocatalytic conditions, water oxidation by 1b is three times faster than that by the parent catalyst 1a at close to the same potential. Extensive computations have identified differences in the initial PCET steps of the water oxidation by catalysts 1a, 1b, and 1d, and demonstrated the increased probability of the O 2 formation via the oxide relay pathway in the order 1b< 1a < 1d.

14 SOLAR ENERGY↗
DOE OSTI2021

Assessing subtle variations in the actinyl oxo reactivity through characterization of neptunyl complexes. Final Report

Formation of the actinyl cation, [An(V,VI)O 2 ] n+ (n = 1,2), imparts unique chemical properties to the lighter actinide elements (U, Np, and Pu) that has yet to be fully understood. The axial O atoms (oxo) of the [An(VI)O 2 ] 2+ are considered weak Lewis bases that exhibit only meager interact with other metal cations and regarded as poor hydrogen acceptors for nearby water molecules. Oxo atoms of [An(V)O 2 ] + should engage in stronger bonding interactions due to a higher degree of Lewis basicity, but the actual interactions have yet to be fully explored. Intermolecular interactions can impact radionuclide separations, corrosion of spent fuel, and mobility of actinides in environmental systems; there is, therefore, a critical need to understand how the subtle difference in electronic properties of the An(V) and An(VI) metal center influence actinyl chemistry. The objective of this proposal was to determine the chemical components that influence the intermolecular interactions occurring between neptunyl ([Np(V)O 2 ] + and [Np(VI)O 2 ] 2+ ) cations and neighboring species. My overall hypothesis was that the intermolecular attraction that occurs between the neptunyl oxo atoms and neighboring species (H atoms, low-valent cations, actinyl cations) is primarily controlled by the electronic properties of the actinyl cation, but can be further influenced by the electron donating properties of the equatorial ligands. The hypothesis was tested through the following research objectives: (1) Determine the fundamental differences in H-bonding between Np(V)O 2+ and Np(VI)O 2 2+ and neighboring donor molecules; (2) Identify the major differences in bonding between low-valence metal cations and neptunyl oxo groups, and (3) Assess the impact of the equatorial ligand on the formation of cation-cation interactions within molecular species. Major outcomes of the research include: (1) More precisely identifying oxo interactions (actinyl-cation; actinyl-actinyl, actinyl-hydrogen) and the factors that impact the vibrational modes for actinyl cation; (2) Identification of H-bonding modes for the [An(V,VI)O 2 ] n+ (n = 1,2), with direct H-bonding interactions to the oxo group of the Np(V)O 2+ cation more prevalent than in hexavalent species and recognition of the importance of H-bonding networks, that can impart bond asymmetry and activation of vibrational modes with the actinyl moiety; (3) Delineation of the importance of charge density for engaging the cation-oxo interaction for both pentavalent and hexavalent species; (4) Determining the importance of sterics and ligand binding in formation of specific actinyl-actinyl interactions and the resulting vibrational modes associated with this bonding motify and (5) Understanding how the functionalization of the ligand can impact redox stability of neptunyl cations. Deliverables from this work include 11 peer-reviewed manuscripts and 13 (including six by graduate students) oral/poster presentations.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on KSn4S3ClO12 by Materials Project

KSn4S3O12Cl crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.04 Å. There are two inequivalent Sn+3.50+ sites. In the first Sn+3.50+ site, Sn+3.50+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Sn–O bond lengths are 2.33 Å. In the second Sn+3.50+ site, Sn+3.50+ is bonded in a 4-coordinate geometry to two O2- and two equivalent Cl1- atoms. There are one shorter (2.45 Å) and one longer (2.49 Å) Sn–O bond lengths. There are one shorter (2.97 Å) and one longer (2.98 Å) Sn–Cl bond lengths. S+3.33+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.46–1.52 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, one Sn+3.50+, and one S+3.33+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to one K1+ and one S+3.33+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one K1+, one Sn+3.50+, and one S+3.33+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Sn+3.50+ and one S+3.33+ atom. Cl1- is bonded in a 12-coordinate geometry to six equivalent Sn+3.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na6Mg3B9P6H3O38 by Materials Project

Na6Mg3B9P6H3O38 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are four inequivalent Na sites. In the first Na site, Na is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Na–O bond distances ranging from 2.40–2.57 Å. In the second Na site, Na is bonded in a 3-coordinate geometry to six O atoms. There are three shorter (2.35 Å) and three longer (2.86 Å) Na–O bond lengths. In the third Na site, Na is bonded in a 7-coordinate geometry to seven O atoms. There are a spread of Na–O bond distances ranging from 2.36–2.71 Å. In the fourth Na site, Na is bonded in a distorted single-bond geometry to seven O atoms. There are a spread of Na–O bond distances ranging from 2.56–3.00 Å. Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two BO4 tetrahedra and corners with four PO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.03–2.28 Å. There are three inequivalent B sites. In the first B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one MgO6 octahedra, a cornercorner with one BO4 tetrahedra, and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 62°. There are a spread of B–O bond distances ranging from 1.43–1.53 Å. In the second B site, B is bonded in a trigonal planar geometry to three O atoms. There is two shorter (1.38 Å) and one longer (1.39 Å) B–O bond length. In the third B site, B is bonded to four O atoms to form BO4 tetrahedra that share a cornercorner with one MgO6 octahedra, a cornercorner with one BO4 tetrahedra, and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of B–O bond distances ranging from 1.43–1.51 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with two BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–53°. There are a spread of P–O bond distances ranging from 1.52–1.59 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent MgO6 octahedra and corners with two BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–52°. There is two shorter (1.53 Å) and two longer (1.57 Å) P–O bond length. H is bonded in a single-bond geometry to one O atom. The H–O bond length is 0.99 Å. There are fourteen inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Na atom. In the second O site, O is bonded in a bent 120 degrees geometry to one Na, one B, and one P atom. In the third O site, O is bonded in a 3-coordinate geometry to one Na, one Mg, and one P atom. In the fourth O site, O is bonded in a 2-coordinate geometry to one Na, one B, and one P atom. In the fifth O site, O is bonded in a 2-coordinate geometry to one Na, one B, and one P atom. In the sixth O site, O is bonded in a distorted trigonal planar geometry to one Na, one Mg, and one P atom. In the seventh O site, O is bonded in a 2-coordinate geometry to two Na, one Mg, and one P atom. In the eighth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na, one Mg, and one P atom. In the ninth O site, O is bonded in a distorted trigonal planar geometry to one Mg and two B atoms. In the tenth O site, O is bonded in a distorted trigonal planar geometry to one Na and two B atoms. In the eleventh O site, O is bonded in a trigonal planar geometry to one Mg and two B atoms. In the twelfth O site, O is bonded in a distorted water-like geometry to two Na, one B, and one H atom. In the thirteenth O site, O is bonded in a bent 120 degrees geometry to one Na, one B, and one P atom. In the fourteenth O site, O is bonded in a single-bond geometry to one Na atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na6Ni3B9P6H3O38 by Materials Project

Na6Ni3B9P6H3O38 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are four inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.46–2.59 Å. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to six O2- atoms. There are three shorter (2.34 Å) and three longer (2.83 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.70 Å. In the fourth Na1+ site, Na1+ is bonded to four O2- atoms to form distorted NaO4 tetrahedra that share corners with six BO4 tetrahedra. There are one shorter (2.45 Å) and three longer (2.80 Å) Na–O bond lengths. Ni+3.33+ is bonded to six O2- atoms to form NiO6 octahedra that share corners with two BO4 tetrahedra and corners with four PO4 tetrahedra. There are a spread of Ni–O bond distances ranging from 2.02–2.28 Å. There are three inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share a cornercorner with one NiO6 octahedra, a cornercorner with one NaO4 tetrahedra, a cornercorner with one BO4 tetrahedra, and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 61°. There are a spread of B–O bond distances ranging from 1.44–1.51 Å. In the second B3+ site, B3+ is bonded to four O2- atoms to form BO4 tetrahedra that share a cornercorner with one NiO6 octahedra, a cornercorner with one NaO4 tetrahedra, a cornercorner with one BO4 tetrahedra, and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 63°. There are a spread of B–O bond distances ranging from 1.44–1.53 Å. In the third B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.39 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent NiO6 octahedra and corners with two BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–54°. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent NiO6 octahedra and corners with two BO4 tetrahedra. The corner-sharing octahedra tilt angles range from 50–53°. There are a spread of P–O bond distances ranging from 1.52–1.58 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one Na1+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one B3+ and one P5+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one B3+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Na1+, one B3+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to one B3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ni+3.33+ and two B3+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to one Ni+3.33+ and two B3+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, one Ni+3.33+, and one P5+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ni+3.33+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Na1+ and two B3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one Ni+3.33+, and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Ni+3.33+, and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted water-like geometry to two Na1+, one B3+, and one H1+ atom. In the fourteenth O2- site, O2- is bonded in a single-bond geometry to one Na1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Synthesis and Characterization of Homoleptic Rare Earth Nitrato Complexes with the Quaternary Ammonium Cations Et 4 N + and n Pr 4 N +

Two periodic series of homoleptic rare earth nitrato com plexes, [R 4 N] x [M(NO 3 ) y ](M = La-Nd, Sm-Lu, Y); R = Et, $n$ Pr; x = 2-3; y = 5-6) have been synthesized, and charac terized by single crystal X-ray diffraction, IR and Raman spectroscopy, comparing the solid state speciation of the nitrate ions as a function of lanthanide ion and quarternary ammonium cation. The series of the form [Et 4 N] 3 [Ln(NO 3 ) 6 ] crystallizes in the rhombohedral space group $R$$\bar{3}$, as a twelve-coordinate hexanitrato complex [Et 4 N] 3 [Ln(NO 3 ) 6 ] with cocrystallized HNO 3 for La, Pr, and Nd. For Ce, a distinct orthorhombic phase retaining the same formula, [Et 4 N] 3 [Ce(NO 3 ) 6 ] is isolated in the absence of HNO 3 to prevent oxidation of the Ce(III) to Ce(IV) in nitric acid. A ten-coordinate pentanitrato complex, [Et 4 N] 2 [Ln(NO 3 ) 5 ], in monoclinic symmetry forms for the remainder of the series, and for Y(III). The entire series crystallized in the presence of [ $n$ Pr 4 N] + counterions forms a pentanitrato complex [ $n$ Pr 4 N] 2 [M(NO 3 ) 5 ] in the orthorhombic space group, $Pccn$. In conclusion, analysis of trends in the structural and spectroscopic characteristics of these series reveal insight into the structure directing influences of both the lanthanide contraction and the quarternary ammonium cations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2024

Terrestrial Ages and Pairing of Howardites, Eucrites and Diogenites From the Miller Range Icefields, Antarctica

In the past 45 years, the US Antarctic Meteorite (ANSMET) program has recovered more than 22,000 meteorites from more than 50 individual meteorite stranding areas. Although the Antarctic meteorite collection is dominated by ordinary chondrites which represent 80-90% of the recovered samples, it also contains many achondrites, including howardites, eucrites and diogenites, which are collectively known as HED meteorites. A challenge for the Antarctic meteorite collection is to identify paired fragments that belong to the same fall. Eight ANSMET field sea-sons at the Miller Range Icefields (MIL), a series of blue ice fields about 40 km long and 10-20 km wide, have yielded more than 3000 meteorites including 56 HEDs. At least three possible pairing groups (with 3-10 members each) were initially identified among the MIL diogenites and one each among the howardites and eucrites. Since many HED meteorites are heterogeneous breccias, pairing identifications based on cm-sized samples is difficult and other independent evidence is needed to verify these proposed pairings, as was shown for several Antarctic howardite pairing-groups. Here we re-examine pairings of HED’s from the Miller Range Icefields, using multiple lines of evidence, including texture/petrography, chemical composition, cosmogenic radionuclides and find locations. Due to the heterogeneous nature of HED meteorites, we will not only consider pairings strictly among the three HED groups, but will also consider pairing of howardites with brecciated eucrites or brecciated diogenites if the cosmogenic nuclides, texture and chemical compositions support this. The concentrations of cosmogenic radionuclides in meteorites are a function of the cosmic-ray exposure (CRE) age, shielding conditions (size and irradiation depth), chemical composition, as well the terrestrial age of the meteorite sample. Since the production rates of cosmogenic nuclides as a function of meteoroid size, depth and composition are well understood [6], their measured concentrations can be used to determine which meteorites belong to the same fall even if the chemical composition of the samples show significant variations. We selected 28 of the 56 HED samples from the MIL collection, including 12 diogenites, 8 howardites and 8 brecciated eucrites to investigate pairing relationships.

howardite↗
DOE OSTI2023

Mesoporous Organosilica Nanoparticles with Internal Metal–Chelating Groups: Transition Metal Uptake and Gd 3+ Relaxivity

We prepared novel mesoporous organosilica nanoparticles with internal metal-chelating diethylenetriametetraacetic acid groups (DTTA-MSNPs) by co-condensation and decorated them with fluorescent moieties. Here, we studied the binding of transition metal ions such as copper(II), cobalt (II) and gadolinium (III) by DTTA-MSNPs, and found high uptake of these metals. In particular, DTTA-MSNPs uptake ~1.1×10 5 Gd 3+ per particle and possess a high r 1 relaxivity of 15.27 mM –1 s –1 . Thus, DTTA-MSNPs may find applications in metal sequestration and in MR imaging and neutron capture therapy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Thermodynamics of calcium binding to heparin: Implications of solvation and water structuring for polysaccharide biofunctions

Heparan sulfates are found in all animal tissues and have essential roles in living systems. This family of biomacromolecules modulates binding to calcium ions (Ca 2+ ) in low free energy reactions that influence biochemical processes from cell signaling and anticoagulant efficacy to biomineralization. Despite their ubiquity, the thermodynamic basis for how heparans and similarly functionalized biomolecules regulate Ca 2+ interactions is not yet established. Using heparosan (Control) and heparins with different positions of sulfate groups, we quantify how SO 3 − and COO − content and SO 3 − position modulate Ca 2+ binding by isothermal titration calorimetry. The free energy of all heparin-Ca2+ interactions (ΔG rxn ) is dominated by entropic contributions due to favorable water release from polar, hydrophilic groups. Heparin with both sulfate esters (O-SO 3 − ) and sulfamides (N-SO 3 − ) has the strongest binding to Ca 2+ compared to heparosan and to heparin with only O-SO 3 − groups (~3X). By linking Ca 2+ binding thermodynamics to measurements of the interfacial energy for calcite (CaCO 3 ) crystallization onto polysaccharides, we show molecule-specific differences in nucleation rate can be explained by differences in water structuring during Ca 2+ interactions. A large entropic term (-TΔS rxn ) upon Ca 2+ –polysaccharide binding correlates with high interfacial energy to CaCO 3 nucleation. Combining our measurements with literature values indicates many Ca 2+ –polysaccharide interactions have a shared thermodynamic signature. The resulting enthalpy–entropy compensation relationship suggests these interactions are generally dominated by water restructuring involving few conformational changes, distinct from Ca 2+ –protein binding. Our findings quantify the thermodynamic origins of heparin-specific interactions with Ca 2+ and demonstrate the contributions of solvation and functional group position during biomacromolecule-mediated ion regulation.

15 GEOTHERMAL ENERGY↗
DOE OSTI2020

Materials Data on NaGaSiO4 by Materials Project

NaGaSiO4 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent GaO4 tetrahedra and corners with six equivalent SiO4 tetrahedra. There are three shorter (2.50 Å) and three longer (2.63 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Na–O bond lengths are 2.46 Å. In the third Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are three shorter (2.33 Å) and three longer (2.57 Å) Na–O bond lengths. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with two equivalent NaO6 octahedra and corners with four equivalent SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–78°. There is three shorter (1.85 Å) and one longer (1.86 Å) Ga–O bond length. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NaO6 octahedra and corners with four equivalent GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 58–64°. There is one shorter (1.64 Å) and three longer (1.65 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to one Na1+, one Ga3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ga3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two Na1+, one Ga3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Ga3+, and one Si4+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2005

ATTITUDE FILTERING ON SO(3)

A new method is presented for the simultaneous estimation of the attitude of a spacecraft and an N-vector of bias parameters. This method uses a probability distribution function defined on the Cartesian product of SO(3), the group of rotation matrices, and the Euclidean space W N .The Fokker-Planck equation propagates the probability distribution function between measurements, and Bayes s formula incorporates measurement update information. This approach avoids all the issues of singular attitude representations or singular covariance matrices encountered in extended Kalman filters. In addition, the filter has a consistent initialization for a completely unknown initial attitude, owing to the fact that SO(3) is a compact space.

Markley, F. Landis↗
DOE OSTI2020

Materials Data on Na3CaAl3Si3CO15 by Materials Project

Na3CaAl3Si3CO15 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. Na1+ is bonded to five O2- atoms to form distorted NaO5 square pyramids that share corners with two equivalent AlO4 tetrahedra, corners with two equivalent SiO4 tetrahedra, edges with two equivalent NaO5 square pyramids, an edgeedge with one AlO4 tetrahedra, and an edgeedge with one SiO4 tetrahedra. There are a spread of Na–O bond distances ranging from 2.15–2.53 Å. Ca2+ is bonded in a 3-coordinate geometry to one C4+ and three equivalent O2- atoms. The Ca–C bond length is 2.22 Å. All Ca–O bond lengths are 2.43 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with two equivalent NaO5 square pyramids, corners with four equivalent SiO4 tetrahedra, and an edgeedge with one NaO5 square pyramid. There are a spread of Al–O bond distances ranging from 1.72–1.85 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent NaO5 square pyramids, corners with four equivalent AlO4 tetrahedra, and an edgeedge with one NaO5 square pyramid. There are a spread of Si–O bond distances ranging from 1.60–1.70 Å. C4+ is bonded in a trigonal planar geometry to one Ca2+ and three equivalent O2- atoms. All C–O bond lengths are 1.29 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Na1+, one Ca2+, and one C4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Al3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Al3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a linear geometry to one Al3+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaZnAsO4 by Materials Project

NaZnAsO4 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form NaO6 octahedra that share corners with six equivalent ZnO4 tetrahedra, corners with six equivalent AsO4 tetrahedra, and a faceface with one NaO6 pentagonal pyramid. There are three shorter (2.48 Å) and three longer (2.58 Å) Na–O bond lengths. In the second Na1+ site, Na1+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Na–O bond lengths are 2.40 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form distorted NaO6 pentagonal pyramids that share corners with six equivalent AsO4 tetrahedra, edges with three equivalent ZnO4 tetrahedra, and a faceface with one NaO6 octahedra. There are three shorter (2.36 Å) and three longer (2.56 Å) Na–O bond lengths. Zn2+ is bonded to four O2- atoms to form ZnO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with four equivalent AsO4 tetrahedra, and an edgeedge with one NaO6 pentagonal pyramid. The corner-sharing octahedra tilt angles range from 64–72°. There are a spread of Zn–O bond distances ranging from 1.97–2.00 Å. As5+ is bonded to four O2- atoms to form AsO4 tetrahedra that share corners with two equivalent NaO6 octahedra, corners with two equivalent NaO6 pentagonal pyramids, and corners with four equivalent ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–67°. There is one shorter (1.72 Å) and three longer (1.73 Å) As–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Zn2+, and one As5+ atom. In the second O2- site, O2- is bonded to two Na1+, one Zn2+, and one As5+ atom to form distorted edge-sharing ONa2ZnAs trigonal pyramids. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Na1+, one Zn2+, and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to one Na1+, one Zn2+, and one As5+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS2004

Preparation of Proton Exchange Membranes and Lithium Batteries from Melamine-containing Ormosils

Our laboratory has recently reported a series of rodcoil polymers for lithium batteries that display dimensionally stable films with good ionic conductivity. The rod segments consist of rigid linear and branched polyimides and the coil segments are polyethylene oxides (PEO). It has been proposed that good mechanical and transport properties are due to phase separation between the rod and coil segments. It was also observed that increased branching and molecular weight lead to increased conductivity. The following study was undertaken to assess the effects of phase separation in polyalkylene oxides connected by melamine linkages. Melamine was chosen as the linking unit because it provides a branching site, cation binding sites to help ionic transport between polymer chains, and the opportunity for self assembly through hydrogen bonding. Polymers were made by the reaction of cyanuric chloride with a series of amine-terminated alkylene oxides. A linear polymer was first made, followed by reaction of the third site on cyanuric chloride with varying ratios of monofunctional Jeffamine and (3-aminopropyl)triethoxysilane. The lithium trifluoromethane sulfonamide-doped polymers are then crosslinked through a sol-gel process to form free-standing films. Initial results have shown mechanically strong films with lithium conductivities on the order of 2 x 10(exp -5) S/cm at ambient temperature. In a separate study, organically modified silanes (Ormosils) that contain sulfonic acid derivatized melamines have been incorporated into proton exchange membranes. The membranes are made by reaction of the primary amine groups of various ratios of melamine derivative and difunctional Jeffamine (MW = 2000) with the epoxide group of (3-Glycidyloxypropyl)trimethoxysilane. The films were then cross-linked through a sol-gel process. Resulting sulfuric acid doped films are strong, flexible, and have proton conductivities on the order of 2 x l0(exp -2) S/cm (120 C, 25% relative humidity). Our best results have been observed when films contain 60% PEO and 40% sulfonated melamine.

Tigelaar, Dean M.↗
DOE OSTI2020

Materials Data on Pr4MnS7 by Materials Project

Pr4MnS7 crystallizes in the hexagonal P6_3 space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to six S2- atoms. There are a spread of Pr–S bond distances ranging from 2.74–3.02 Å. In the second Pr3+ site, Pr3+ is bonded in a rectangular see-saw-like geometry to four S2- atoms. There are one shorter (2.70 Å) and three longer (2.71 Å) Pr–S bond lengths. Mn2+ is bonded in a 3-coordinate geometry to six equivalent S2- atoms. There are three shorter (2.37 Å) and three longer (3.27 Å) Mn–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to three equivalent Pr3+ and two equivalent Mn2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three Pr3+ atoms. In the third S2- site, S2- is bonded in a tetrahedral geometry to four Pr3+ atoms.

36 MATERIALS SCIENCE↗