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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Multiplex Evolution of Antibody Fragments Utilizing a Yeast Surface Display Platform

Advances in high-throughput synthetic biology technologies based on the CRISPR/Cas9 system have enabled a comprehensive assessment of mutations conferring desired phenotypes, as well as a better understanding of genotype-phenotype correlations in protein engineering. Engineering antibodies to enhance properties such as binding affinity and stability plays an essential role in therapeutic applications. Here we report a method, multiplex navigation of antibody structure (MINAS), that combines a CRISPR/Cas9-based trackable editing method and fluorescent-activated cell sorting (FACS) of yeast-displayed libraries. We designed mutations in all of the complementarity-determining and framework regions of a well-characterized scFv antibody and mapped the contribution of these regions to enhanced properties. We identified specific mutants that showed higher binding affinities up to 100-fold compared to the wild-type. This study expands the applicability of CRISPR/Cas9-based trackable protein engineering by combining it with a surface display platform.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2026

Selective Reduction of Carbon Dioxide in Water Using [M(bpy2+)(CO)3(I)]2+ (M = Mn, Re) Electrocatalysts with Pendent Cations

Manganese(I) carbonyl complexes are promising electrocatalysts for CO2 reduction, yet their application in homogeneous aqueous media remains limited by poor solubility and selectivity. Here, we report water-soluble Mn(I) and Re(I) complexes fac-[M(bpy2+)(CO)3X]2+ (X = I or Cl), featuring bipyridine ligands functionalized with -Ph-CH2-(NMe3)+ cationic ammonium groups that integrate water solubility with secondary-sphere stabilization. In bicarbonate buffer at pH 6.8, the Mn catalyst is completely selective for CO production at a low overpotential (η = 0.3 V), operating by a protonation-first mechanism with observed rates of ~10 s−1. Pulse radiolysis reveals that the one-electron reduced Mn species undergoes dimerization in the absence of CO2 but uniquely reacts competitively with CO2 through an initial pre-equilibrium followed by fast formation of a dinuclear CO2-bridged species (ΔGo = −12.4 kcal mol−1). At a higher 0.6 V over-potential, a faster reduction-first pathway (~100 s−1) is available upon reduction of the metallo-carboxylic acid intermediate, Mn-CO2H2+; however, this regime is functionally limited by the formation of a resistive, noncatalytic film on the electrode surface. Comparison to the analo-gous water-soluble Re catalyst (kobs = 440 s−1, η = 0.6 V) highlights the distinct mechanistic ad-vantages of earth-abundant Mn in low-potential catalysis. These results demonstrate how cati-onic second-sphere design enables selective, homogeneous CO2 reduction in water while reveal-ing competing radical and electrode-mediated processes that govern catalytic performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Activity-based, genome-resolved metagenomics uncovers key populations and pathways involved in subsurface conversions of coal to methane

Microbial metabolisms and interactions that facilitate subsurface conversions of recalcitrant carbon to methane are poorly understood. We deployed an in situ enrichment device in a subsurface coal seam in the Powder River Basin (PRB), USA, and used BONCAT-FACS-Metagenomics to identify translationally active populations involved in methane generation from a variety of coal-derived aromatic hydrocarbons. From the active fraction, high-quality metagenome-assembled genomes (MAGs) were recovered for the acetoclastic methanogen, Methanothrix paradoxum, and a novel member of the Chlorobi with the potential to generate acetate via the Pta-Ack pathway. Members of the Bacteroides and Geobacter also encoded Pta-Ack and together, all four populations had the putative ability to degrade ethylbenzene, phenylphosphate, phenylethanol, toluene, xylene, and phenol. Metabolic reconstructions, gene analyses, and environmental parameters also indicated that redox fluctuations likely promote facultative energy metabolisms in the coal seam. The active "Chlorobi PRB" MAG encoded enzymes for fermentation, nitrate reduction, and multiple oxygenases with varying binding affinities for oxygen. "M. paradoxum PRB" encoded an extradiol dioxygenase for aerobic phenylacetate degradation, which was also present in previously published Methanothrix genomes. Finaly, these observations outline underlying processes for bio-methane from subbituminous coal by translationally active populations and demonstrate activity-based metagenomics as a powerful strategy in next generation physiology to understand ecologically relevant microbial populations.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2022

Subsurface hydrocarbon degradation strategies in low- and high-sulfate coal seam communities identified with activity-based metagenomics

Environmentally relevant metagenomes and BONCAT-FACS derived translationally active metagenomes from Powder River Basin coal seams were investigated to elucidate potential genes and functional groups involved in hydrocarbon degradation to methane in coal seams with high- and low-sulfate levels. An advanced subsurface environmental sampler allowed the establishment of coal-associated microbial communities under in situ conditions for metagenomic analyses from environmental and translationally active populations. Metagenomic sequencing demonstrated that biosurfactants, aerobic dioxygenases, and anaerobic phenol degradation pathways were present in active populations across the sampled coal seams. In particular, results suggested the importance of anaerobic degradation pathways under high-sulfate conditions with an emphasis on fumarate addition. Under low-sulfate conditions, a mixture of both aerobic and anaerobic pathways was observed but with a predominance of aerobic dioxygenases. The putative low-molecular-weight biosurfactant, lichysein, appeared to play a more important role compared to rhamnolipids. The methods used in this study—subsurface environmental samplers in combination with metagenomic sequencing of both total and translationally active metagenomes—offer a deeper and environmentally relevant perspective on community genetic potential from coal seams poised at different redox conditions broadening the understanding of degradation strategies for subsurface carbon.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Novel lamprey antibody recognizes terminal sulfated galactose epitopes on mammalian glycoproteins

The terminal galactose residues of N- and O-glycans in animal glycoproteins are often sialylated and/or fucosylated, but sulfation, such as 3-O-sulfated galactose (3-O-SGal), represents an additional, but poorly understood modification. To this end, we have developed a novel sea lamprey variable lymphocyte receptor (VLR) termed O6 to explore 3-O-SGal expression. O6 was engineered as a recombinant murine IgG chimera and its specificity and affinity to the 3-O-SGal epitope was defined using a variety of approaches, including glycan and glycoprotein microarray analyses, isothermal calorimetry, ligand-bound crystal structure, FACS, and immunohistochemistry of human tissue macroarrays. 3-O-SGal is expressed on N-glycans of many plasma and tissue glycoproteins, but recognition by O6 is often masked by sialic acid and thus exposed by treatment with neuraminidase. O6 recognizes many human tissues, consistent with expression of the cognate sulfotransferases (GAL3ST-2 and GAL3ST-3). The availability of O6 for exploring 3-O-SGal expression could lead to new biomarkers for disease and aid in understanding the functional roles of terminal modifications of glycans and relationships between terminal sulfation, sialylation and fucosylation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2021

Accessing the triplet manifold of naphthalene benzimidazole–phenanthroline in rhenium(i) bichromophores

In this work, the steady-state and ultrafast to supra-nanosecond excited state dynamics of fac-[Re(NBI-phen)(CO) 3 (L)](PF 6 ) (NBI-phen = 16H-benzo[4',5']isoquinolino[2',1':1,2]imidazo[4,5-f][1,10]phenanthrolin-16-one) as well as their respective models of the general molecular formula [Re(phen)(CO) 3 (L)](PF 6 ) (L = PPh 3 and CH 3 CN) has been investigated using transient absorption and time-gated photoluminescence spectroscopy. The NBI-phen containing molecules exhibited enhanced visible light absorption with respect to their models and a rapid formation (<6 ns) of the triplet ligand-centred (LC) excited state of the organic ligand, NBI-phen. These triplet states exhibit an extended excited state lifetime that enable the energized molecules to readily engage in triplet–triplet annihilation photochemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Reactivity of radiolytically and photochemically generated tertiary amine radicals towards a CO 2 reduction catalyst

Homogeneous solar fuels photocatalytic systems often require several additives in solution with the catalyst to operate, such as a photosensitizer (PS), Brønsted acid/base, and a sacrificial electron donor (SED). Tertiary amines, in particular triethylamine (TEA) and triethanolamine (TEOA), are ubiquitously deployed in photocatalysis applications as SEDs and are capable of reductively quenching the PS’s excited state. Upon oxidation, TEA and TEOA form TEA •+ and TEOA •+ radical cations, respectively, which decay by proton transfer to generate redox non-innocent transient radicals, TEA • and TEOA • , respectively, with redox potentials that allow them to participate in an additional electron transfer step, thus resulting in net one-photon/two-electron donation. However, the properties of the TEA • and TEOA • radicals are not well understood, including their reducing powers and kinetics of electron transfer to catalysts. Herein, we have used both pulse radiolysis and laser flash photolysis to generate TEA • and TEOA • radicals in CH 3 CN, and combined with UV/Vis transient absorption and time-resolved mid-infrared spectroscopies, we have probed the kinetics of reduction of the well-established CO 2 reduction photocatalyst, fac-ReCl(bpy)(CO) 3 (bpy = 2,2'-bipyridine), by these radicals [k TEA• = (4.4 ± 0.3) × 10 9 M –1 s –1 and k TEOA• = (9.3 ± 0.6) × 10 7 M –1 s –1 ]. The ~50× smaller rate constant for TEOA • indicates, that in contrast to a previous assumption, TEA • is a more potent reductant than TEOA • (by ~0.2 V, as estimated using the Marcus cross relation). This knowledge will aid in the design of photocatalytic systems involving SEDs. Furthermore, we also show that TEA can be a useful radiolytic solvent radical scavenger for pulse radiolysis experiments in CH 3 CN, effectively converting unwanted oxidizing radicals into useful reducing equivalents in the form of TEA • radicals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

An Improved Boosting to Amplify Signal with Isobaric Labeling (iBASIL) Strategy for Precise Quantitative Single-cell Proteomics

Mass spectrometry (MS)-based proteomics has great potential for overcoming the limitations of antibody-based immunoassays for antibody-independent, comprehensive, and quantitative proteomic analysis of single cells. Indeed, recent advances in nanoscale sample preparation have enabled effective processing of single cells. In particular, the concept of using boosting/carrier channels in isobaric labeling to increase the sensitivity in MS detection has also been increasingly used for quantitative proteomic analysis of small-sized samples including single cells. However, the full potential of such boosting/carrier approaches has not been significantly explored, nor has the resulting quantitation quality been carefully evaluated. Herein, we have further evaluated and optimized our recent boosting to amplify signal with isobaric labeling (BASIL) approach, originally developed for quantifying phosphorylation in small number of cells, for highly effective analysis of proteins in single cells. This improved BASIL (iBASIL) approach enables reliable quantitative single-cell proteomics analysis with greater proteome coverage by carefully controlling the boosting-to-sample ratio (e.g. in general <100×) and optimizing MS automatic gain control (AGC) and ion injection time settings in MS/MS analysis (e.g. 5E5 and 300 ms, respectively, which is significantly higher than that used in typical bulk analysis). By coupling with a nanodroplet-based single cell preparation (nanoPOTS) platform, iBASIL enabled identification of ~2500 proteins and precise quantification of ~1500 proteins in the analysis of 104 FACS-isolated single cells, with the resulting protein profiles robustly clustering the cells from three different acute myeloid leukemia cell lines. This study highlights the importance of carefully evaluating and optimizing the boosting ratios and MS data acquisition conditions for achieving robust, comprehensive proteomic analysis of single cells.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

Electron collisional excitation cross-section measurements and modeling for select Ni-like to Ge-like gold transitions

We have experimentally determined the electron collisional excitation cross-sections for several 3d→4f and 3d→5f excitations in Ni- to Ge-like Au at energies of ~ 0.4, 1, 2, and 3 keV above threshold energy, E T , for the 3d→4f excitations ( E T ~ 2.5 keV) and ~ 0.2, 1, and 2 keV above threshold energy for the 3d→5f excitations ( E T ~ 3.3 keV). The cross-section measurements are possible by using the GSFC micro-calorimeter to record emission spectra from beam plasmas created in the Livermore EBIT-I electron beam ion trap. The cross-sections are experimentally determined from the ratio of the measured intensities of the collisionally excited lines to the intensities of the radiative recombination lines in monoenergetic electron distribution EBIT-I plasmas. The effects of polarization and Auger processes in the beam plasmas are accounted for in the cross-section determination. Experimentally determined cross-sections are compared with those from HULLAC, DWS, and FAC calculations. Finally, the measurements exhibit significant differences with the calculations of these excitation cross-sections.

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2020

Materials Data on Ti2NbNi9 by Materials Project

Ti2NbNi9 is Uranium Silicide-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are five inequivalent Ti sites. In the first Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with four TiNi12 cuboctahedra, corners with eight NbNi12 cuboctahedra, edges with twenty-four NiTi3NbNi8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.54–2.57 Å. In the second Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with four TiNi12 cuboctahedra, corners with eight NbNi12 cuboctahedra, edges with twenty-four NiTi2Nb2Ni8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.54–2.58 Å. In the third Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with six TiNi12 cuboctahedra, corners with twelve NiTi3NbNi8 cuboctahedra, edges with eighteen NiTi2Nb2Ni8 cuboctahedra, faces with four TiNi12 cuboctahedra, faces with four NbNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.56–2.61 Å. In the fourth Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with six TiNi12 cuboctahedra, corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with eighteen NiTi3NbNi8 cuboctahedra, faces with three TiNi12 cuboctahedra, faces with five NbNi12 cuboctahedra, and faces with twelve NiTi2Nb2Ni8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.56–2.61 Å. In the fifth Ti site, Ti is bonded to twelve Ni atoms to form TiNi12 cuboctahedra that share corners with six TiNi12 cuboctahedra, corners with twelve NiTi3NbNi8 cuboctahedra, edges with eighteen NiTi3NbNi8 cuboctahedra, faces with three NbNi12 cuboctahedra, faces with five TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Ti–Ni bond distances ranging from 2.56–2.60 Å. There are four inequivalent Nb sites. In the first Nb site, Nb is bonded to twelve Ni atoms to form NbNi12 cuboctahedra that share corners with two equivalent TiNi12 cuboctahedra, corners with ten NbNi12 cuboctahedra, edges with twenty-four NiTi2Nb2Ni8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Nb–Ni bond distances ranging from 2.56–2.61 Å. In the second Nb site, Nb is bonded to twelve Ni atoms to form NbNi12 cuboctahedra that share corners with four equivalent TiNi12 cuboctahedra, corners with eight NbNi12 cuboctahedra, edges with twenty-four NiTi2Nb2Ni8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Nb–Ni bond distances ranging from 2.55–2.60 Å. In the third Nb site, Nb is bonded to twelve Ni atoms to form NbNi12 cuboctahedra that share corners with six TiNi12 cuboctahedra, corners with six NbNi12 cuboctahedra, edges with twenty-four NiTi3NbNi8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi3NbNi8 cuboctahedra. There are a spread of Nb–Ni bond distances ranging from 2.55–2.61 Å. In the fourth Nb site, Nb is bonded to twelve Ni atoms to form NbNi12 cuboctahedra that share corners with four TiNi12 cuboctahedra, corners with eight NbNi12 cuboctahedra, edges with twenty-four NiTi3NbNi8 cuboctahedra, faces with six TiNi12 cuboctahedra, and faces with twelve NiTi2Nb2Ni8 cuboctahedra. There are a spread of Nb–Ni bond distances ranging from 2.56–2.60 Å. There are twenty-seven inequivalent Ni sites. In the first Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with four TiNi12 cuboctahedra, edges with four NbNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi2Nb2Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–2.62 Å. In the second Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.49–2.64 Å. In the third Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–2.62 Å. In the fourth Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with four TiNi12 cuboctahedra, edges with four NbNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi2Nb2Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.52–2.61 Å. In the fifth Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.52–2.60 Å. In the sixth Ni site, Ni is bonded to two equivalent Ti, two Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.51–2.62 Å. In the seventh Ni site, Ni is bonded to two equivalent Ti, two equivalent Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with four equivalent TiNi12 cuboctahedra, edges with four NbNi12 cuboctahedra, edges with sixteen NiTi2Nb2Ni8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two equivalent NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. All Ni–Ni bond lengths are 2.57 Å. In the eighth Ni site, Ni is bonded to two equivalent Ti, two equivalent Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi2Nb2Ni8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two equivalent NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. All Ni–Ni bond lengths are 2.58 Å. In the ninth Ni site, Ni is bonded to two equivalent Ti, two equivalent Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two equivalent NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are two shorter (2.58 Å) and two longer (2.59 Å) Ni–Ni bond lengths. In the tenth Ni site, Ni is bonded to three Ti, one Nb, and eight Ni atoms to form distorted NiTi3NbNi8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with three NbNi12 cuboctahedra, edges with five TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, a faceface with one NbNi12 cuboctahedra, faces with three TiNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.49–2.64 Å. In the eleventh Ni site, Ni is bonded to three Ti, one Nb, and eight Ni atoms to form distorted NiTi3NbNi8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with three NbNi12 cuboctahedra, edges with five TiNi12 cuboctahedra, edges with sixteen NiTi2Nb2Ni8 cuboctahedra, a faceface with one NbNi12 cuboctahedra, faces with three TiNi12 cuboctahedra, and faces with fourteen NiTi2Nb2Ni8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–2.63 Å. In the twelfth Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two equivalent NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–2.63 Å. In the thirteenth Ni site, Ni is bonded to three Ti, one Nb, and eight Ni atoms to form distorted NiTi3NbNi8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with three NbNi12 cuboctahedra, edges with five TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, a faceface with one NbNi12 cuboctahedra, faces with three TiNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.52–2.61 Å. In the fourteenth Ni site, Ni is bonded to three Ti, one Nb, and eight Ni atoms to form distorted NiTi3NbNi8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with three NbNi12 cuboctahedra, edges with five TiNi12 cuboctahedra, edges with sixteen NiTi2Nb2Ni8 cuboctahedra, a faceface with one NbNi12 cuboctahedra, faces with three TiNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.50–2.63 Å. In the fifteenth Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two equivalent NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with four TiNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. There are a spread of Ni–Ni bond distances ranging from 2.51–2.61 Å. In the sixteenth Ni site, Ni is bonded to two equivalent Ti, two equivalent Nb, and eight Ni atoms to form distorted NiTi2Nb2Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with two equivalent NbNi12 cuboctahedra, edges with six TiNi12 cuboctahedra, edges with sixteen NiTi2Nb2Ni8 cuboctahedra, faces with two equivalent TiNi12 cuboctahedra, faces with two equivalent NbNi12 cuboctahedra, and faces with fourteen NiTi3NbNi8 cuboctahedra. All Ni–Ni bond lengths are 2.56 Å. In the seventeenth Ni site, Ni is bonded to four Ti and eight Ni atoms to form distorted NiTi4Ni8 cuboctahedra that share corners with twelve NiTi2Nb2Ni8 cuboctahedra, edges with three NbNi12 cuboctahedra, edges with five TiNi12 cuboctahedra, edges with sixteen NiTi3NbNi8 cuboctahedra, faces with four TiNi12 cuboctahedra, and fac

36 MATERIALS SCIENCE↗
DOE OSTI2023

Reducing the matrix effect in mass spectral imaging of biofilms using flow-cell culture

The interactions between soil microorganisms and soil minerals play a crucial role in the formation and evolution of minerals and the stability of soil aggregates. Due to the heterogeneity and diversity of the soil environment, the under-standing of the functions of bacterial biofilms in soil minerals at the microscale is limited. A soil mineral-bacterial biofilm system was used as a model in this study, and it was analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) to acquire molecular level information. Static culture in multi-wells and dynamic flow-cell culture in microfluidics of biofilms were investigated. Our results show that more characteristic molecules of biofilms can be observed in SIMS spectra of the flow-cell culture. In contrast, biofilm signature peaks are buried under the mineral components in SIMS spectra in the static culture case. Spectral overlay was used in peak selection prior to performing Principal component analysis (PCA). Comparisons of the PCA results between the static and flow-cell culture show more pronounced molecular features and higher loadings of organic peaks of the dynamic cultured specimens. For example, fatty acids secreted from bacterial biofilm extracellular polymeric substance are likely to be responsible for biofilm dispersal due to mineral treatment up to 48 h. Such findings suggest that the use of microfluidic cells to dynamically culture biofilms be a more suitable method for reducing the matrix effect arisen from the growth medium and minerals as a perturbation fac-tor for improved spectral and multivariate analysis of complex mass spectral data in ToF-SIMS. These results show that the interaction mechanism between biofilms and soil minerals at the molecular level can be better studied using the flow-cell culture and advanced mass spectral imaging techniques like ToF-SIMS.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1986

Destiny of earthward streaming plasma in the plasmasheet boundary layer

The dynamics of the earth's magnetotail have been investigated, and it has become clear that the plasmasheet boundary layer field lines map into the Region I Field-Aligned Currents (FAC) of the auroral zone. It is pointed out that the role of earthward streaming ions in the plasmasheet boundary layer may be of fundamental importance in the understanding of magnetotail dynamics, auroral zone physics, and especially for ionospheric-magnetospheric interactions. The present paper has the objective to evaluate propagation characteristics for the earthward streaming ions observed in the plasmasheet boundary layer. An investigation is conducted of the propagation characteristics of protons in the plasmasheet boundary layer using independent single particle dynamics, and conclusions are discussed. The density of earthward streaming ions found in the plasmasheet boundary layer should include the ring current as well as the auroral zone precipitaiton and inner plasmasheet regions of the magnetosphere.

Green, J. L.↗
NASA NTRS1990

Airbus windshear warning and guidance system

From its first designed airplane, Airbus considered mandatory a help in the crew's decision-making process to initiate an escape maneuver and help to successfully realize it. All the Airbus airplanes designed since 1975 included an alpha-floor function and a speed reference control law imbedded in the speed reference system (SRS) box for A 300 and FAC and FCC for A 310, A300/600 and the A 320. Alpha-Floor function takes into account the airplane energy situation considering angle of attack and observed longitudinal situation in order to apply immediately the full power without any pilot action. Speed reference managers control airspeed and/or ground speed in order to survive a maximum in shear situation. In order to comply with the new FAA regulation: Aerospatiale and Airbus developed more efficient systems. A comparison between 1975 and a newly developed system is given. It is explained how the new system improves the situation.

Bonafe, J. L.↗
NASA NTRS1993

Coupling of magnetopause-boundary layer to the polar ionosphere

The plasma dynamics in the low-latitude boundary layer and its coupling to the polar ionosphere under boundary conditions at the magnetopause are investigated. In the presence of a driven plasma flow along the magnetopause, the Kelvin-Helmholtz instability can develop, leading to the formation and growth of plasma vortices in the boundary layer. The finite ionospheric conductivity leads to the decay of these vortices. The competing effect of the formation and decay of vortices leads to the formation of strong vortices only in a limited region. Several enhanced field-aligned power density regions associated with the boundary layer vortices and the upward field-aligned current (FAC) filaments can be found along the postnoon auroral oval. These enhanced field-aligned power density regions may account for the observed auroral bright spots.

Wei, C. Q.↗
NASA NTRS1993

An object-oriented approach for parallel self adaptive mesh refinement on block structured grids

Self-adaptive mesh refinement dynamically matches the computational demands of a solver for partial differential equations to the activity in the application's domain. In this paper we present two C++ class libraries, P++ and AMR++, which significantly simplify the development of sophisticated adaptive mesh refinement codes on (massively) parallel distributed memory architectures. The development is based on our previous research in this area. The C++ class libraries provide abstractions to separate the issues of developing parallel adaptive mesh refinement applications into those of parallelism, abstracted by P++, and adaptive mesh refinement, abstracted by AMR++. P++ is a parallel array class library to permit efficient development of architecture independent codes for structured grid applications, and AMR++ provides support for self-adaptive mesh refinement on block-structured grids of rectangular non-overlapping blocks. Using these libraries, the application programmers' work is greatly simplified to primarily specifying the serial single grid application and obtaining the parallel and self-adaptive mesh refinement code with minimal effort. Initial results for simple singular perturbation problems solved by self-adaptive multilevel techniques (FAC, AFAC), being implemented on the basis of prototypes of the P++/AMR++ environment, are presented. Singular perturbation problems frequently arise in large applications, e.g. in the area of computational fluid dynamics. They usually have solutions with layers which require adaptive mesh refinement and fast basic solvers in order to be resolved efficiently.

Lemke, Max↗
NASA NTRS1997

NASA University Program Management Information System

As basic policy, NASA believes that colleges and universities should be encouraged to participate in the nation's space and aeronautics program to the maximum extent practicable. Indeed, universities are considered as partners with government and industry in the nation's aerospace program. NASA's objective is to have them bring their scientific, engineering, and social research competence to bear on aerospace problems and on the broader social, economic, and international implications of NASA's technical and scientific programs. It is expected that, in so doing, universities will strengthen both their research and their educational capabilities to contribute more effectively to the national well-being. NASA field codes and certain Headquarters program offices provide funds for those activities in universities which contribute to the mission needs of that particular NASA element. Although NASA has no predetermined amount of money to devote to university activities, the effort funded each year is substantial. This annual report is one means of documenting the NASA-university relationship, frequently denoted, collectively, as NASA's University Program. This report is consistent with agency accounting records, as the data is obtained from NASA's Financial and Contractual Status (FACS) System, operated by the Financial Management Division and the Procurement Office. However, in accordance with interagency agreements, the orientation differs from that required for financial or procurement purposes. Any apparent discrepancies between this report and other NASA procurement or financial reports stem from the selection criteria for the data. This report was prepared by the Education Division/FE, Office of Human Resources and Education, using a management information system which was modernized during FY 1993.

Gans, Gary↗
NASA NTRS1999

NASA University Program Management Information System

As basic policy, NASA believes that colleges and universities should be encouraged to participate in the nation's space and aeronautics program to the maximum extent practicable. Indeed, universities are considered as partners with government and industry in the nation's aerospace program. NASA's objective is to have them bring their scientific, engineering, and social research competence to bear on aerospace problems and on the broader social, economic, and international implications of NASA's technical and scientific programs. It is expected that, in so doing, universities will strengthen both their research and their educational capabilities to contribute more effectively to the national well-being. NASA field codes and certain Headquarters program offices provide funds for those activities in universities which contribute to the mission needs of that particular NASA element. Although NASA has no predetermined amount of money to devote to university activities, the effort funded each year is substantial. (See the bar chart on the next page). This annual report is one means of documenting the NASA-university relationship, frequently denoted, collectively, as NASA's University Program. This report is consistent with agency accounting records, as the data is obtained from NASA's Financial and Contractual Status (FACS) System, operated by the Financial Management Division and the Procurement Office. However, in accordance with interagency agreements, the orientation differs from that required for financial or procurement purposes. Any apparent discrepancies between this report and other NASA procurement or financial reports stem from the selection criteria for the data.

Source record↗
NASA NTRS1999

Significance of Landsat-7 Spacecraft Level Thermal Balance and Thermal Test for ETM+Instrument

The thermal design and the instrument thermal vacuum (T/V) test of the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) instrument were based on the Landsat-4, 5 and 6 heritage. The ETM+ scanner thermal model was also inherited from Landsat-4, 5 and 6. The temperature predictions of many scanner components in the original thermal model had poor agreement with the spacecraft and instrument integrated sun-pointing safehold (SPSH) thermal balance (T/B) test results. The spacecraft and instrument integrated T/B test led to a change of the Full Aperture Calibrator (FAC) motor stack "solar shield" coating from MIL-C-5541 to multi-layer insulation (MLI) thermal blanket. The temperature predictions of the Auxiliary Electronics Module (AEM) in the thermal model also had poor agreement with the T/B test results. Modifications to the scanner and AEM thermal models were performed to give good agreement between the temperature predictions and the test results. The correlated ETM+ thermal model was used to obtain flight temperature predictions. The flight temperature predictions in the nominal 15-orbit mission profile, plus margins, were used as the yellow limits for most of the ETM+ components. The spacecraft and instrument integrated T/B and TN test also revealed that the standby heater capacity on the Scan Mirror Assembly (SMA) was insufficient when the Earth Background Simulator (EBS) was 1 50C or colder, and the baffle heater possibly caused the coherent noise in the narrow band data when it was on. Also, the cooler cool-down was significantly faster than that in the instrument T/V test, and the coldest Cold Focal Plane Array (CFPA) temperature achieved was colder.

Choi, Michael K.↗