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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Thermal performance of a catalytic/oxidizer for the Space Station Freedom

Thermal analysis and testing have been performed for the High Temperature Catalytic/Oxidizer (HTCO) for the Space Station Freedom (SSF) Trace Contaminant Control Subassembly (TCCS). The HTCO consists of a counterflow, plate-fin heat exchanger, a resistance heater, and a charcoal catalytic oxidizer bed. The unit removes various inorganics and hydrocarbons from the SSF cabin air. A thermal model of the unit was developed which was used to design the HEX and catalytic bed. The model has been used to predict both steady state and transient results. Accurate predictions of ground test data have led to confidence in proper operation of the unit in the SSF.

Wedel, R. K.↗
NASA NTRS2001

Vitamin C-sulfate inhibits mineralization in chondrocyte cultures: a caveat

Differentiating chick limb-bud mesenchymal cell micro-mass cultures routinely mineralize in the presence of 10% fetal calf serum, antibiotics, 4 mM inorganic phosphate (or 2.5 mM beta-glycerophosphate), 0.3 mg/ml glutamine and either 25 microg/ml vitamin C or 5-12 microg/ml vitamin C-sulfate. The failure of these cultures to produce a mineralized matrix (assessed by electron microscopy, 45Ca uptake and Fourier transform infrared microscopy) led to the evaluation of each of these additives. We report here that the "stable" vitamin C-sulfate (ascorbic acid-2-sulfate) causes increased sulfate incorporation into the cartilage matrix. Furthermore, the release of sulfate from the vitamin C derivative appears to be responsible for the inhibition of mineral deposition, as demonstrated in cultures with equimolar amounts of vitamin C and sodium sulfate.

NASA Discipline Musculoskeletal↗
DOE OSTI2021

Programmable Matter: The Nanoparticle Atom and DNA Bond

Colloidal crystal engineering with DNA has led to significant advances in bottom-up materials synthesis and a new way of thinking about fundamental concepts in chemistry. Here, programmable atom equivalents (PAEs), comprised of nanoparticles (the “atoms”) functionalized with DNA (the “bonding elements”), are assembled through DNA hybridization into crystalline lattices. Unlike atomic systems, the “atom” (e.g., the nanoparticle shape, size, and composition) and the “bond” (e.g., the DNA length and sequence) can be tuned independently, yielding designer materials with unique catalytic, optical, and biological properties. Here in this review, nearly three decades of work that have contributed to the evolution of this class of programmable matter is chronicled, starting from the earliest examples based on gold-core PAEs, and then delineating how advances in synthetic capabilities, DNA design, and fundamental understanding of PAE-PAE interactions have led to new classes of functional materials that, in several cases, have no natural equivalent.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Nitrogen-Defective Polymeric Carbon Nitride Nanolayer Enabled Efficient Electrocatalytic Nitrogen Reduction with High Faradaic Efficiency

Identifying highly selective catalysts and accurately measuring NH 3 yield without false-positives from contaminations remain two challenges in electrochemical nitrogen reduction reaction (NRR). Here, we report N-defective carbon nitride grown on carbon paper (CN/C) as a highly selective electrocatalyst. The NH 3 yield was determined reliably by the slope of mNH 3 -time plot rather than averaging the accumulated amount over time. Results showed the as-synthesized CN/ C 600 (synthesized at 600 °C) with a higher density of C=N-C N2C vacancies achieved an NH 3 production of 2.9 μg mgcat. -1 h -1 at -0.3 V (versus RHE), ~5.7-fold higher than CN/C 500 . The Faradaic efficiency for CN/ C 600 is among the highest of 62.1%, 33.9%, and 16.8% at -0.1 V, -0.2 V, and -0.3 V, respectively. The NH 3 production was verified by isotope 15 N 2 experiments. Further increase of N-defects on CN/C 600 using plasma etching led to higher NH 3 yield than comparably larger current, pointing to N-defects sites for promoting NRR.

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

Achieving a blue-excitable yellow-emitting Ca-LMOF phosphor via water induced phase transformation

Luminescent metal-organic frameworks (LMOFs) with diverse structural features and promising fluorescence-based applications have attracted wide attention in the past two decades. In this work, a LMOF with the formula [Ca 4 (tcbpe-F) 2 (H 2 O) 3 ] (1, LMOF-411) has been constructed from calcium (Ca) and 1,1,2,2-tetrakis(4-(4-carboxyphenyl)phenyl)ethene (H 4 tcbpe-F). Compound 1 features a three-dimensional framework with a 10-nodal net topology. Due to the relatively high hydration energy of Ca 2+ , compound 1 readily transforms into a new phase formulated as [Ca(H 2 tcbpe-F)(H 2 O) 2 ] (1') upon exposure to water. Combining experimental characterization and theoretical calculations, we elucidated the mechanism of H 2 O-induced phase transition from 1 to 1'. Notably, the water induced phase transformation can be detected visibly from the change in luminescence, which originates from the fluorescent linker. Compound 1 emits green light ( λ em = 490 nm) under UV excitation, while compound 1' emits bright yellow light ( λ em = 550 nm) under blue excitation (450 nm). Compound 1' represents the first Ca based LMOF yellow phosphor and its luminescence quantum yield reaches 68%. It can be coated directly onto a commercial blue light-emitting-diode (LED) chip to fabricate a white LED (WLED).

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

Progress and outlook of Sn–Pb mixed perovskite solar cells

Abstract Organic–inorganic hybrid perovskites have revolutionized solar cell research owing to their excellent material properties. Most previous research has been done on Pb-based perovskites. Recently, efforts to discover a Pb-free or Pb-less perovskite material with an ideal bandgap ranging 1.1–1.3 eV have led researchers to investigate Sn–Pb mixed perovskites. Sn–Pb mixed perovskites have a bandgap of ~ 1.25 eV, which is suitable for high-efficiency single-junction and perovskite/perovskite tandem solar cells. Moreover, the Pb content of Sn–Pb mixed perovskites is 50–60% lower than that of Pb-based perovskites, partially mitigating the Pb toxicity issue. However, incorporating Sn 2+ into the crystal structure also causes various drawbacks, such as inhomogeneous thin film morphologies, easy oxidation of Sn 2+ , and more vulnerable surface properties. Researchers have made substantial progress in addressing these challenges through improvements in compositional design, structural optimization, precursor design, and surface treatments. In this review, we provide a comprehensive overview of the progress in Sn–Pb mixed perovskite solar cells. Furthermore, we analyze the key variables and trends as well as provide an outlook for future directions in the research on Sn–Pb mixed perovskites. Graphical Abstract

14 SOLAR ENERGY↗
DOE OSTI2021

Binding of noble gas atoms by superhalogens

Because of their closed shells, noble gas (Ng) atoms (Ng = Ne, Ar, Kr, and Xe) seldom take part in chemical reactions, yet finding such mechanisms not only is of scientific interest but also has practical significance. Following a recent work by Mayer et al. [Proc. Natl. Acad. Sci. U. S. A. 116, 8167–8172 (2019)] on the room temperature binding of Ar to a superelectrophilic boron site embedded in a negative ion complex, B 12 (CN) 11 - , we have systematically studied the effect of cluster size and terminal ligands on the interaction of Ng by focusing on B 12 X 11 (Ng) (X = H, CN, and BO) and B 12 X 10 (Ng) 2 (X = CN and BO) whose stabilities are governed by the Wade–Mingos rule and on C 5 BX 5 (Ng) (X = H, F, and CN) and C 4 B 2 (CN) 4 (Ng) 2 whose stabilities are governed by the Huckel’s aromaticity rule. Our conclusion, based on density functional theory, is that both the cluster size and the terminal ligands matter—the interaction between the cluster and the Ng atoms becomes stronger with increasing cluster size and the electron affinity of the terminal ligands. Our studies also led to a counter-intuitive finding—removing multiple terminal ligands can enable electrophilic centers to bind multiple Ng atoms simultaneously without compromising their binding strength.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1990

Isomeric Trisaryloxycyclotriphosphazene Polymer Precursors

Substances useful for making heat-and fire-resistant polymers. Cyclotriphosphazene-based monomers and polymer precursors led to development of high-temperature materials. Cyclotriphosphazene-derived monomers, polymer precursors, and polymers becoming important from both industrial and scientific points of view. Presence of phosphazene moiety in cyclotriphosphazene-based monomers and polymer precursors expected to impact special properties in desired high-performance materials containing inorganic backbones for aerospace applications. Useful for obtaining heat-and fire-resistant polymers for composites, adhesives, molding powders, and coating laminates. Also used in structures (e.g. secondary structures in aircraft), in construction of spacecraft, and in electronics and computer industries.

St. Clair, Terry L.↗
NASA NTRSDate not supplied

Contamination monitoring of the OSIRIS-REx ISO5 asteroid sample cleanroom

The OSIRIS-REx mission to asteroid Bennu successfully collected hundreds of grams of asteroid regolith in October 2020 [1]. The spacecraft departed Bennu in May 2021 for Earth return and will release the sample canister to be recovered in Utah in September 2023 [2]. Samples will be transported to the curation facility at NASA Johnson Space Center, where an ISO5 equivalent cleanroom has been designed in 2017 and completed in 2021. Aspects of the design and material selection for the cleanroom and its supporting facilities (air handling system, cleanroom floors and walls, filters, paints, etc.) were optimized to minimize effects of organic and inorganic contaminants and offgassing [3]. Since its completion, the lab has been carefully monitored to understand and establish a baseline with respect to multiple environmental aspects – measurement of particle counts, deploying Si wafer witness plates for organic and inorganic contaminants, deploying aluminum foils for a focus on organics with JSC in-house expertise, gas samples, and regular microbial and fungal measurements on selected surfaces and air samples in the cleanroom. This contribution will report on nearly one year of monitoring and highlight several specific aspects that have led to a better understanding of the new cleanroom environment.

carbonaceous asteroid↗
DOE OSTI2022

Transformation of brucine into trifluoromethyl neobrucine using the homoleptic nickel catalyst [Ni(CF3)4]2-

The homoleptic trifluoromethyl nickel complex [Ni(CF3)4]2- catalyzes a stereoselective trifluoromethylation of brucine with Umemoto II reagent. The trifluoromethylation process proceeds with concomitant isomerization of its alkenyl double bond leading to a trifluoromethylated neobrucine-like derivative. A minor difunctionalization product was also detected from the reaction mixture, consistent with a radical addition process that is occurring in parallel. Stoichiometric reactions between the nickel(II) catalyst precursor and brucine led to no reaction. However, a stochiometric reaction with a high-valent nickel(IV) complex formed trifluoromethylated neobrucine, implicating its intermediacy.

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

Self-Adhesive Ionomers for Alkaline Electrolysis: Optimized Hydrogen Evolution Electrode

Hydrogen produced through low-temperature water electrolysis using anion exchange membranes (AEM) combines the benefits of liquid-electrolyte alkaline electrolysis and solid-polymer proton exchange membrane electrolysis. The anion conductive ionomers in the oxygen-producing anode and hydrogen-producing cathode are a critical part of the three-dimensional electrodes. The ionomer in the hydrogen-producing cathode facilitates hydroxide ion conduction from the cathode catalyst to the anode catalyst, and water transport from the anode to the cathode catalyst through the AEM. This ionomer also binds the catalyst particles to the porous transport layer. Here in this study, the cathode durability was improved by use of a self-adhesive cathode ionomer to chemically bond the cathode catalyst particles to the porous transport layer. It was found that the cathode ionomers with high ion exchange capacity (IEC) were more effective than low IEC ionomers because of the need to transport water to the cathode catalyst and transport hydroxide away from the cathode. The cathode durability was improved by using ionomers which were soluble in the spray-coated cathode ink. Optimization of the catalyst and ionomer content within the cathode led to electrolysis cells which were both mechanically durable and operated at low voltage.

08 HYDROGEN↗
DOE OSTI2024

Electrodeposition of Tungsten using Hydrotropic Agents

The current work sought to electrodeposit tungsten from water-based solutions. The work’s initial hypothesis was that methoxide reducing agents could be used to generate urea anions that could enable tungsten electrodeposition. Unfortunately, this hypothesis was found to be incorrect. However, the work led to the understanding that chemical reducing agents not only enable the electrodeposition of refractory metals like rhenium from water-based solutions, but that the key to plating tungsten in the future involves chemical reduction followed by stabilization with proper ligands. The work resulted in a manuscript under review at Inorganic Chemistry Communications on the discovered of L-histidine as a suitable reducing agent from rhenium electrodeposition. Rhenium-tungsten alloys with 4% tungsten were deposited. A technical advance was filed for the rhenium chemistry and parts were delivered to an internal Sandia customer that used the chemistry.

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

NMR Investigations of Crystalline and Glassy Solid Electrolytes for Lithium Batteries: A Brief Review

The widespread use of energy storage for commercial products and services have led to great advancements in the field of lithium-based battery research. In particular, solid state lithium batteries show great promise for future commercial use, as solid electrolytes safely allow for the use of lithium-metal anodes, which can significantly increase the total energy density. Of the solid electrolytes, inorganic glass-ceramics and Li-based garnet electrolytes have received much attention in the past few years due to the high ionic conductivity achieved compared to polymer-based electrolytes. This review covers recent work on novel glassy and crystalline electrolyte materials, with a particular focus on the use of solid-state nuclear magnetic resonance spectroscopy for structural characterization and transport measurements.

Morales, Daniel J. (ORCID:0000000271845727)↗
NASA NTRS1990

Carbonate petrography, kerogen distribution, and carbon and oxygen isotope variations in an early Proterozoic transition from limestone to iron-formation deposition, Transvaal Supergroup, South Africa

The transition zone comprises Campbellrand microbialaminated (replacing "cryptalgalaminate") limestone and shale, with minor dolomite, conformably overlain by the Kuruman Iron Formation of which the basal part is characterized by siderite-rich microbanded iron-formation with minor magnetite and some hematite-containing units. The iron-formation contains subordinate intraclastic and microbialaminated siderite mesobands and was deposited in deeper water than the limestones. The sequence is virtually unaltered with diagenetic mineral assemblages reflecting a temperature interval of about 110 degrees to 170 degrees C and pressures of 2 kbars. Carbonate minerals in the different rock types are represented by primary micritic precipitates (now recrystallized to microsparite), early precompactional sparry cements and concretions, deep burial limpid euhedral sparites, and spar cements precipitated from metamorphic fluids in close contact with diabase sills. Paragenetic pathways of the carbonate minerals are broadly similar in all lithofacies with kerogen intimately associated with them. Kerogen occurs as pigmentation in carbonate crystals, as reworked organic detritus in clastic-textured carbonate units, and as segregations of kerogen pigment around late diagenetic carbonate crystals. Locally kerogen may also be replaced by carbonate spar. Carbon isotope compositions of the carbonate minerals and kerogen are dependent on their mode of occurrence and on the composition of the dominant carbonate species in a specific lithofacies. Integration of sedimentary, petrographic, geochemical, and isotopic results makes it possible to distinguish between depositional, early diagenetic, deep burial, and metamorphic effects on the isotopic compositions of the carbonate minerals and the kerogen in the sequence. Major conclusions are that deep burial thermal decarboxylation led to 13C depletion in euhedral ferroan sparites and 13C enrichment in kerogen (organic carbon). Metamorphic sparites are most depleted in 13C. Carbonates in oxide-rich iron-formations are more depleted in 13C than those in siderite-rich iron-formation whereas the kerogens in oxide banded iron-formations (BIF) are more enriched. This implies that the siderite-rich iron-formations were not derived from oxide-rich iron-formation through reduction of ferric iron by organic matter. Organic matter oxidation by ferric iron did, however, decrease the abundance of kerogen in oxide-rich iron-formation and led to the formation of isotopically very light sparry carbonates. Siderite and calcmicrosparite both represent recrystallized primary micritic precipitates but differ in their 13C composition, with the siderites depleted in 13C by 4.6 per mil on average relative to calcmicrosparite. This means that the siderites were precipitated from water with dissolved inorganic carbon depleted in 13C by about 9 per mil relative to that from which the limestones precipitated. This implies an ocean system stratified with regard to total carbonate, with the deeper water, from which siderite-rich iron-formation formed, depleted in 13C. Iron-formations were deposited in areas of very low organic matter supply. Depletion of 13C may, therefore, derive not from degradation of organic matter but from hydrothermal activity, a conclusion which is supported by 18O composition of the carbonate minerals and trace element and rare earth element (REE) compositions of the iron-formations.

NASA Discipline Number 52-30↗
DOE OSTI2021

Modifying the pore size distribution in Fe-rich inorganic polymer mortars: An effective shrinkage mitigation strategy

Highlights: • Inorganic polymer mortar has mainly macropores and a drying shrinkage of 5.1 mm/m. • 2-methyl-2,4-pentanediol acts as air entrainer in inorganic polymer mortars. • Optimal dosage 2 wt% 2-methyl-2,4-pentanediol reduced drying shrinkage to 1.8 mm/m. • Heat curing inorganic polymer mortars reduced drying shrinkage more than 50%. • Blast Furnace slag addition increased drying shrinkage and reduced strength. Inorganic polymer (IP) binder is formed upon alkali-activation of Fe-rich (41 wt%) metallurgical slag leading to materials with mechanical properties comparable to ordinary Portland cement binders. Crack formation is reported in IPs, which can be related to volumetric stability, which is to date not thoroughly understood in IPs. This study determined the autogenous and drying shrinkage of IP mortars. Shrinkage mitigation strategies, such as the addition of 2-methyl-2,4-pentanediol (2MPL), blast furnace slag (GGBFS), and applying heat curing, were used separately or in combination. IP mortars exhibited autogenous expansion and high drying shrinkage. The addition of 2MPL led to a porosity increase, as air was entrained, decreasing the drying shrinkage with 64%. Additional heat curing had no effect on samples with 2MPL. Introducing GGBFS resulted in smaller pores, increasing drying shrinkage. Shrinkage in IP mortars is driven by its pore size distribution and higher shrinkage resulted in lower flexural strength.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Mechanistic insights into Cr(VI) removal by a combination of zero-valent iron and pyrite

Recent studies have revealed that a combination of zero-valent iron (ZVI) and pyrite (FeS 2 ) can effectively remove (Cr(VI)) from water, but the reasons behind this synergistic effect are still unclear. Our batch experiments showed that dissolved oxygen (DO) is a critical factor in the improved removal of Cr(VI) by ZVI and pyrite. When 0.08 g/L pyrite was combined with 0.5 g/L ZVI in the presence of DO, total Cr was reduced from 10 mg/L to 0.02 mg/L within 6 h. Conversely, in the absence of DO, total Cr was only reduced to 5.6 mg/L. DO oxidation of pyrite produced protons that promote ZVI corrosion, and mixing pyrite with water creates dissolved sulfide, which also contributes to the improved removal of Cr(VI). Here, electron microscopy images and X-ray absorption near edge structure analyses revealed that the presence of dissolved sulfide led to the formation of ferrous sulfide precipitates on the ZVI surface, preventing the formation of a passivating layer.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2011

Isotopic Evidence for the Source and Fate of Phosphorus in Everglades Wetland Ecosystems

Phosphorus has historically been a limiting nutrient in the Florida Everglades. Increased P loading to the Everglades over the past several decades has led to significant changes in water quality and plant communities. Stormwater runoff that drains agricultural lands and enters the Water Conservation Areas (WCAs) are known to contain elevated levels of P, but the exact source of this P has not been fully determined. Here the results of an O isotope study of dissolved inorganic phosphate (DIP) in both polluted and relatively pristine (or reference) areas of the Everglades are reported. The data reveal spatial and temporal variations in the delta 18O signature of DIP, reflecting the source and the degree of cycling of P. The delta 18O values of DIP collected from the Everglades National Park were close or equal to the predicted delta 18O values of DIP formed in situ in equilibrium with ambient water, indicating that P is quickly cycled in the water column in oligotrophic ecosystems with very low P concentrations. However, most DIP samples collected from areas impacted by agricultural runoff yielded delta 18O values that deviated from the predicted equilibrium DIP delta 18O values based on the delta 18O of water and water temperature, suggesting that biological cycling of P was not rapid enough to remove the fertilizer ?18O signature in the DIP pool from areas receiving high P loading. The delta 18O signature of DIP in impacted areas reflects a mixing of fertilizer P and biologically cycled P, where the relative proportions of biologically cycled vs. fertilizer DIP are controlled by both biological (microbial activities and plant uptake) and hydrologic factors (loading rate and residence time). Using a two-end-member (i.e., fertilizer P and biologically cycled P) mixing model, fertilizers were estimated to contribute about 15 100% of the DIP pool in the highly impacted areas of the northern Everglades, whereas the DIP pool in the reference (i.e., relatively pristine) wetlands in the Everglades National Park was dominated by biologically cycled P. The study shows that O isotopic measurements of dissolved PO(exp 3-, sub 4) can be a useful tool for tracing the fertilizer P inputs to freshwater ecosystems.

Li, Xin↗