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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1993

Films Containing Optically Nonlinear Diacetylene Monomer

Solid films exhibiting nonlinear optical properties prepared as mixtures of poly(methyl methacrylate) with various amounts of diacetylene monomer called "compound 1" in article, "Synthesizing Diacetylenes With Nonlinear Optical Properties" (MFS-26186). Useful as phase-conjugate mirrors in laser-beam communications and as optical switches in optical computers. This particular diacetylene monomer exhibits strong third-order nonlinear optical properties, both in pure form and in solution.

Paley, Mark S.↗
NASA NTRSDate not supplied

Low-Temperature Formation of Carbonaceous Grains from PAHs

Astronomical observations have detected interstellar carbon in the form of polycyclic aromatic hydrocarbons(PAHs) as well as carbonaceous dust, confirming its presence in both gaseous and solid phases. The goal of this study is to experimentally investigate low-temperature chemical pathways between these two phases in order to better understand the evolution of cosmic carbon. Cosmic dust analogs are produced in the supersonic expansion of an argon jet seeded with aromatic molecules: benzene, naphthalene, anthracene, phenanthrene, and pyrene. These are prototype aromatic molecules of compact and non compact structure, and are used to evaluate the effect of precursor structure on the molecular complexity of the resulting grains. The seeded jet is exposed to an electrical discharge and the carbonaceous grains are collected and probed ex situ via laser desorption mass spectrometry. Mass spectra reveal a rich molecular diversity within the grains, including fragments of the parent molecule but also growth into larger complex organic molecules (COMs). In all experiments, the largest number of products is found in the m/z range 200-250, and C16H10 (attributed to pyrene and/or its isomers) is found to be a dominant product, pointing at the formation of this stable PAH as a preferential route in the growth to larger PAHs. Comparison to mass spectra from the Murchison meteorite reveals a similar dominance of compounds related toC16H10 at m/z = 202. Evidence of the methyl addition-cyclization mechanism in the anthracene experiment is reported. PAH structure is found to impact the dust production yield, as seen by the greater yield for the anthracene compared to the phenanthrene experiment. PAH growth at low temperatures via barrierless routes involving the addition of alkyl- and phenyl-type radicals is suggested as a viable pathway to COMs. These results suggest that PAH growth and dust formation from PAHs are feasible at low temperatures in photon-dominated regions and circumstellar envelopes.

L Gavilan↗
NASA NTRS1975

Raman spectra of gases. XVI - Torsional transitions in ethanol and ethanethiol

The Raman spectra of gaseous ethanol and ethanethiol have been investigated. Thiol torsional fundamentals for the gauche conformer of EtSH and EtSD have been observed and the asymmetric potential function for this vibration has been calculated. Methyl torsional transitions and overtones have also been observed for both of these molecules. Barriers to internal rotation for the methyl top are calculated to be 3.77 and 3.84 kcal/mol for the EtSH and EtSD compounds, respectively. Hydroxyl torsional fundamentals were observed at 207 and 170 per cm in the EtOH and EtOD spectra, respectively. Overtones of the methyl torsion in both molecules yield a barrier to internal rotation of 3.62 kcal/mol for the gauche conformer.

Durig, J. R.↗
DOE OSTI2020

Anaerobic guilds responsible for mercury methylation in boreal wetlands of varied trophic status serving as either a methylmercury source or sink

Wetlands are common sites of active Hg methylation by anaerobic microbes; however, the amount of methylmercury produced varies greatly, as Hg methylation is dependent upon both the availability of Hg and the composition and activity of the microbial community involved. In this study, we identified the major microbial guilds responsible for Hg methylation along a trophic gradient composed of two sites and three different types of wetlands: a bog–fen peatland gradient and a black alder swamp, serving as net sources and a sink for methylmercury respectively. Iron-reducing bacteria in the Geobacteraceae were important Hg methylators across all wetlands and seasons examined, as evidenced by abundant 16S rRNA and hgcA transcripts clustering with this family. Molybdate inhibited Hg methylation more efficiently in the peatlands than in the swamp, suggesting an increasing role of sulfate-reducing bacteria and/or related syntrophs in the methylation of Hg with decreasing trophic status. Further, sulfate addition failed to increase Hg methylation rates in the peatlands, suggesting that SRBs/syntrophs were instead likely metabolizing alternative substrates such as syntrophic fermentation of organic compounds with methanogens. These results highlight the interconnectivity of anaerobic metabolism and importance of community dynamics on the methylation of Hg in wetlands with different trophic status.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Additives for lithium batteries and methods

Lithium tetrafluoro(malonato)phosphate compounds are useful as additives in lithium ion battery applications. The compounds are represented by Formula (I): MPF4[—O(C═O)—(CX′X″)—(C═O)O—]; wherein M is Li or Na; each X′ and X″ independently is selected from the group consisting of H, alkyl, fluoro-substituted alkyl, and F; or wherein the X′ and X″ together are —CR2—(CR′2)m—CR″2—; each R, R′ and R″ independently is selected from the group consisting of H, methyl, trifluoromethyl, and F; and m is 0 or 1. These compounds can be prepared in high purity and a high yield by reaction of a metal hexafluorophosphate with a bis-silyl malonate compound. A similar oxalato compound, lithium tetrafluoro(oxalato)phosphate), can be made in the same manner, but using a bis-silyl oxalate in place of the bis-silyl malonate. Advantageously, the compounds can be formed, in situ, in a LiPF6-containing electrolyte solution.

Liao, Chen↗
DOE OSTI2023

Additives for lithium batteries and methods

Lithium tetrafluoro(malonato)phosphate compounds are useful as additives in lithium ion battery applications. The compounds are represented by Formula (I): MPF 4 [—O(C═O)—(CX′X″)—(C═O)O—]; wherein M is Li or Na; each X′ and X″ independently is selected from the group consisting of H, alkyl, fluoro-substituted alkyl, and F; or wherein the X′ and X″ together are —CR 2 —(CR′ 2 ) m —CR″ 2 —; each R, R′ and R″ independently is selected from the group consisting of H methyl, trifluoromethyl, and F; and in is 0 or 1. These compounds can be prepared in high purity and a high yield by reaction of a metal hexafluorophosphate with a bis-silyl malonate compound. A similar oxalato compound, lithium tetrafluoro(oxalato)phosphate), can be made in the same manner, but using a bis-silyl oxalate in place of the bis-silyl malonate. Advantageously, the compounds can be formed, in situ, in a LiPF 6 -containing electrolyte solution.

Liao, Chen↗
DOE OSTI2020

Competitive Adsorption of Lubricant Base Oil and Ionic Liquid Additives at Air/Liquid and Solid/Liquid Interfaces

Oil-soluble ionic liquids (ILs) have been proved as effective additives in lubricant oils through tribological experiments and post-test analytical analyses. Here, surface structures of lubricant base oil, oil-soluble ILs, and their mixtures at the air/liquid and solid/liquid interfaces have been studied using sum frequency generation (SFG) vibrational spectroscopy. At the air/base oil and air/IL interfaces, the alkyl chains of the studied compounds were shown to be conformationally disordered and their terminal methyl groups point outward at the liquid surface. The base oil dominates the air/(base oil + IL) interface due to its higher surface excess propensity and larger bulk concentration. At the solid (silica) surface, ILs adopt a structure with their charged headgroups in contact with the silica surface, while their alkyl chains are more conformationally ordered or packed compared to the air/IL interface. At the interface between silica and (base oil + IL) mixtures, ILs also preferentially adsorb to the silica surface with their layer structures somewhat different from those of ILs alone. These results showed that ILs can adsorb onto the solid surface even before tribological contacts are made. The insights obtained from this SFG study provide a better understanding of the role of ionic liquids in lubrication.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Oxidative Cascade Cyclization of 1,2-Dicyanoarenes by a Dicopper(I,I) Nitrite Complex to Phthalimide Ligands

The reactions of [Cu2(μ–κ 1:κ 1 -O2N)­DPFN]­[NTf2] (1; DPFN = 2,7-bis­(fluoro-di­(2-pyridyl)­methyl)-1,8-naphthyridine, NTf2 – = N­(SO2CF3)2 –) with 1,4-dicyanobenzene and 1,2-dicyanoarenes are discussed. Treatment of 1 with 1,4-dicyanobenzene produces a tetra-Cu­(I) terephthalate complex (2) and dinitrogen via a discrete CN triple bond cleavage at each cyano group. However, reactions of 1 with 1,2-dicyanoarenes appear to proceed via a cascade reaction involving two intertwined CN triple bond activations to yield a series of di-Cu­(I) phthalimides, [Cu2(μ–N­(CO)2(Ar))­DPFN]­[NTf2] (3-(Ar); Ar = 1,2-arylenes C6H4, 3-NO2C6H3, 4-NO2C6H3, 4-PrOC6H3, 3-NC5H3) and dinitrogen. The dicopper phthalimide bonding interaction in these compounds is robust enough to resist protonation by pentafluorophenol and alkylation by methyl triflate or benzyl chloride at the imide nitrogen. This characteristic presents an opportunity for postsynthetic modifications of the phthalimide ligand. Nevertheless, treatment of 3-(C 6 H 4 ) with bistriflimidic acid (HNTf2) results in release of the neutral phthalimide, making the dicopper core available to coordinate other ligands such as nitrite and thus, completing a stoichiometric cycle.

Fernandez, Jose Martinez↗
DOE OSTI2020

Metabolic Profiling of Volatile Organic Compounds (VOCs) Emitted by the Pathogens Francisella tularensis and Bacillus anthracis in Liquid Culture

We conducted comprehensive (untargeted) metabolic profiling of volatile organic compounds (VOCs) emitted in culture by bacterial taxa Francisella tularensis (F. tularensis) subspecies novicida and Bacillus anthracis (B. anthracis) Sterne, surrogates for potential bacterial bioterrorism agents, as well as selective measurements of VOCs from their fully virulent counterparts, F. tularensis subspecies tularensis strain SCHU S4 and B. anthracis Ames. F. tularensis and B. anthracis were grown in liquid broth for time periods that covered logarithmic growth, stationary, and decline phases. VOCs emitted over the course of the growth phases were collected from the headspace above the cultures using solid phase microextraction (SPME) and were analyzed using gas chromatography-mass spectrometry (GC-MS). We developed criteria for distinguishing VOCs originating from bacteria versus background VOCs (originating from growth media only controls or sampling devices). Analyses of collected VOCs revealed methyl ketones, alcohols, esters, carboxylic acids, and nitrogen- and sulfur-containing compounds that were present in the bacterial cultures and absent (or present at only low abundance) in control samples indicating that these compounds originated from the bacteria. Distinct VOC profiles where observed for F. tularensis when compared with B. anthracis while the observed profiles of each of the two F. tularensis and B. anthracis strains exhibited some similarities. Furthermore, the relative abundance of VOCs was influenced by bacterial growth phase. These data illustrate the potential for VOC profiles to distinguish pathogens at the genus and species-level and to discriminate bacterial growth phases. The determination of VOC profiles lays the groundwork for non-invasive probes of bacterial metabolism and offers prospects for detection of microbe-specific VOC biomarkers from two potential biowarfare agents.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1977

Origin of organic matter in the early solar system. VII - The organic polymer in carbonaceous chondrites

Degradation techniques, including pyrolysis, depolymerization, and oxidation, were used to study the insoluble polymer from the Murchison C2 chondrite. Oxidation with Cr2O7(2-) or O2/UV led to the identification of 15 aromatic ring systems. Of 11 aliphatic acids identified, three dicarboxylic acids presumably came from hydroaromatic portions of the polymer, whereas eight monocarboxylic acids probably derive from bridging groups or ring substituents. Depolymerization with CF3COO4 yielded some of the same ring systems, as well as alkanes (C1 through C8) and alkenes (C2 through C8), alkyl (C1 through C5) benzenes and naphthalenes, and methyl- or dimethyl -indene, -indane, -phenol, -pyrrole, and -pyridine. All these compounds were detected below 200 C, and are therefore probably indigenous constituents. The properties of the meteoritic polymer were compared with the properties of a synthetic polymer produced by the Fischer-Tropsch reaction. It is suggested that the meteoritic polymer was also produced by surface catalysis.

Hayatsu, R.↗
NASA NTRS2004

Synthesis and Characterization of Ru(II) Tris(1,1O-phenanthroline)-Electron Acceptor Dyads Incorporating the 4-benzoyl-N-methylpyridinium Cation or N-Benzyl-N'-methyl-viologen. Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Optical Oxygen Sensors

The title compounds (1 and 2, above) were synthesized by Sonogashira coupling reactions of appropriate Ru(1I) complexes with the electron a cceptors. Characterization was conducted in solution and in frozen ma trices. Finally, the title compounds were evaluated as dopants of sol-gel materials. It was found that the intramolecular quenching efficie ncy of 4-benzoyl-Nmethylpyridinium cation in solution depends on the solvent: photoluminescence is quenched completely in CH,CN, but not i n methanol or ethanol. On the other hand, intramolecular emission que nching by 4-benzyl-N-methyl viologen is complete in all solvents. The difference between the two quenchers is traced electrochemically to t he solvation of the 4-benzoyl-Nmethylpyridiniums by alcohol. In froze n matrices or adsorbed on the surfaces of silica aerogel, both Ru(I1) complex/electron acceptor dyads of this study are photoluminescent, and the absence of quenching has been traced to the environmental rigi dity. When doped aerogels are cooled at 77 K, the emission intensity increases by approximately 4x, and the spectra shift to the blue, analogous to what is observed with Ru(I1) complexes in solutions undergoi ng fluid-to-rigid transition. However, in contrast to frozen solution s, the luminescent moieties in the bulk of aerogels kept at low tempe ratures are still accessible to gas-phase quenchers diffusing through the mesopores, leading to more sensitive platforms for sensors than o ther room-temperature configurations. Thus the photoluminescence of o ur Ru(I1) complex dyads adsorbed on aerogel is quenchable by O2 both at room temperature and at 77 K. Furthermore, it was also found that O 2 modulates the photoluminescence of aerogels doped with 4-benzoyl -N -methylpyridinium-based dyads over a wider dynamic range compared wi th aerogels doped with either our vislogen-based dyads or with Ru(I1) tris(1,lO-phenanthroline) itself.

Leventis, Nicholas↗
DOE OSTI2024

An expedited screening platform for the discovery of anti-ageing compounds in vitro and in vivo

Background: Restraining or slowing ageing hallmarks at the cellular level have been proposed as a route to increased organismal lifespan and healthspan. Consequently, there is great interest in anti-ageing drug discovery. However, this currently requires laborious and lengthy longevity analysis. Here, we present a novel screening readout for the expedited discovery of compounds that restrain ageing of cell populations in vitro and enable extension of in vivo lifespan. Methods: Using Illumina methylation arrays, we monitored DNA methylation changes accompanying long-term passaging of adult primary human cells in culture. This enabled us to develop, test, and validate the CellPopAge Clock, an epigenetic clock with underlying algorithm, unique among existing epigenetic clocks for its design to detect anti-ageing compounds in vitro. Additionally, we measured markers of senescence and performed longevity experiments in vivo in Drosophila, to further validate our approach to discover novel anti-ageing compounds. Finally, we bench mark our epigenetic clock with other available epigenetic clocks to consolidate its usefulness and specialisation for primary cells in culture. Results: We developed a novel epigenetic clock, the CellPopAge Clock, to accurately monitor the age of a population of adult human primary cells. We find that the CellPopAge Clock can detect decelerated passage-based ageing of human primary cells treated with rapamycin or trametinib, well-established longevity drugs. We then utilise the CellPopAge Clock as a screening tool for the identification of compounds which decelerate ageing of cell populations, uncovering novel anti-ageing drugs, torin2 and dactolisib (BEZ-235). We demonstrate that delayed epigenetic ageing in human primary cells treated with anti-ageing compounds is accompanied by a reduction in senescence and ageing biomarkers. Finally, we extend our screening platform in vivo by taking advantage of a specially formulated holidic medium for increased drug bioavailability in Drosophila. We show that the novel anti-ageing drugs, torin2 and dactolisib (BEZ-235), increase longevity in vivo. Conclusions: Our method expands the scope of CpG methylation profiling to accurately and rapidly detecting anti-ageing potential of drugs using human cells in vitro, and in vivo, providing a novel accelerated discovery platform to test sought after anti-ageing compounds and geroprotectors.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2023

Metabolically diverse microorganisms mediate methylmercury formation under nitrate-reducing conditions in a dynamic hydroelectric reservoir

Brownlee Reservoir is a mercury (Hg)-impaired hydroelectric reservoir that exhibits dynamic hydrological and geochemical conditions and is located within the Hells Canyon Complex in Idaho, USA. Methylmercury (MeHg) contamination in fish is a concern in the reservoir. While MeHg production has historically been attributed to sulfate-reducing bacteria and methanogenic archaea, microorganisms carrying the hgcA gene are taxonomically and metabolically diverse and the major biogeochemical cycles driving mercury (Hg) methylation are not well understood. In this study, Hg speciation and redox-active compounds were measured throughout Brownlee Reservoir across the stratified period in four consecutive years (2016–2019) to identify the location where and redox conditions under which MeHg is produced. Metagenomic sequencing was performed on a subset of samples to characterize the microbial community with hgcA and identify possible links between biogeochemical cycles and MeHg production. Biogeochemical profiles suggested in situ water column Hg methylation was the major source of MeHg. These profiles, combined with genome-resolved metagenomics focused on hgcA-carrying microbes, indicated that MeHg production occurs in this system under nitrate- or manganese-reducing conditions, which were previously thought to preclude Hg-methylation. Using this multidisciplinary approach, we identified the cascading effects of interannual variability in hydrology on the redox status, microbial metabolic strategies, abundance and metabolic diversity of Hg methylators, and ultimately MeHg concentrations throughout the reservoir. This work expands the known conditions conducive to producing MeHg and suggests that the Hg-methylation mitigation efforts by nitrate or manganese amendment may be unsuccessful in some locations.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2013

Detection and Quantification of Nitrogen Compounds in Martian Solid Samples by the Sample Analysis at Mars (SAM) Instrument Suite

The Sample Analysis at Mars (SAM) instrument suite on the Mars Science Laboratory (MSL) Curiosity Rover detected both reduced and oxidized nitrogen-bearing compounds during the pyrolysis of surface materials from three sites at Gale Crater. Preliminary detections of nitrogen species include NO, HCN, ClCN, CH3CN, and TFMA (trifluoro-Nmethyl-acetamide). On Earth, nitrogen is a crucial bio-element, and nitrogen availability controls productivity in many environments. Nitrogen has also recently been detected in the form of CN in inclusions in the Martian meteorite Tissint, and isotopically heavy nitrogen (delta N-15 approx +100per mille) has been measured during stepped combustion experiments in several SNC meteorites. The detection of nitrogen-bearing compounds in Martian regolith would have important implications for the habitability of ancient Mars. However, confirmation of indigenous Martian nitrogen bearing compounds will require ruling out their formation from the terrestrial derivatization reagents (e.g. N-methyl-N-tert-butyldimethylsilyl-trifluoroacetamide, MTBSTFA and dimethylformamide, DMF) carried for SAM's wet chemistry experiment that contribute to the SAM background. The nitrogen species we detect in the SAM solid sample analyses can also be produced during laboratory pyrolysis experiments where these reagents are heated in the presence of perchlorate, a compound that has also been identified by SAM in Mars solid samples. However, this does not preclude a Martian origin for some of these compounds, which are present in nanomolar concentrations in SAM evolved gas analyses. Analysis of SAM data and laboratory breadboard tests are underway to determine whether nitrogen species are present at higher concentrations than can be accounted for by maximum estimates of nitrogen contribution from MTBSTFA and DMF. In addition, methods are currently being developed to use GC Column 6, (functionally similar to a commercial Q-Bond column), to separate and identify unretained compounds such as NO, N2O, and NO2, which are difficult to detect by EGA-MS due to mass interferences at 30, 44 and 46, respectively. Here we present evolved gas analysis-mass spectrometry (EGA-MS) and gas chromatography mass spectrometry (GC-MS) data on the identification and quantification of these nitrogen-bearing compounds, and suggestions for their origins

Stern, Jennifer C.↗
DOE OSTI2021

Low rotational barriers for the most dynamically active methyl groups in the proposed antiviral drugs for treatment of SARS-CoV-2, apilimod and tetrandrine

A recent screening study highlighted a molecular compound, apilimod, for its efficacy against the SARS-CoV-2 virus, while another compound, tetrandrine, demonstrated a remarkable synergy with the benchmark antiviral drug, remdesivir. In this work, we find that because of significantly reduced potential energy barriers, which also give rise to pronounced quantum effects, the rotational dynamics of the most dynamically active methyl groups in apilimod and tetrandrine are much faster than those in remdesivir. Because dynamics of methyl groups are essential for biochemical activity, screening studies based on the computed potential energy profiles may help identify promising candidates within a given class of drugs.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2026

Biobased Polybenzoxazine Derived from Furfurylamine and Piceol with Low Cure Temperature and Advanced Properties for Composite Matrices

A novel benzoxazine made from furfurylamine, paraformaldehyde, and piceol, Bz-FA-HA, is assessed for applications in fiber reinforced (FR) composites. Piceol is a biobased phenolic compound derived from the roots of Norwegian spruce trees and contains a methyl ketone group at the para position. Bz-FA-HA is a liquid at room temperature, has a viscosity of < 1 Pa.s at temperatures above 90 °C, and a Tonset of cure at 132 °C. The carbonyl is found to react with the furan ring, yielding a crosslinking reaction, when cured above 180 °C as indicated by differential scanning calorimetry and thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. Poly(Bz-FA-HA) has a Tg > 350 °C, attributed to the crosslinking reaction. Furthermore, the storage modulus is > 3 GPa, regardless of cure temperature. Poly(Bz-FA-HA) has a char yield at 800 °C of 65.0 % (62.3 % at 1000 °C), and a Tonset of decomposition of 357 °C in nitrogen. The resulting carbon formed during pyrolysis shrinks during the carbonization reaction and scanning electron microscopy imaging shows a cross-section with micro cracks. The high processability, advanced mechanical properties, and exceptional char yield make it a promising candidate as the matrix for FR composites.

Benzoxazine↗
DOE OSTI2022

Oxidation of p-[125I]Iodobenzoic Acid and p-[211At]Astatobenzoic Acid Derivatives and Evaluation In Vivo

The alpha particle-emitting radionuclide astatine-211 (211At) is of interest for targeted radiotherapy; however, low in vivo stability of many 211At-labeled cancer-targeting molecules has limited its potential. As an alternative labeling method, we evaluated whether a specific type of astatinated aryl compound that has the At atom in a higher oxidation state might be stable to in vivo deastatination. In the research effort, para-iodobenzoic acid methyl ester and dPEG4-amino acid methyl ester derivatives were prepared as HPLC standards. The corresponding para-stannylbenzoic acid derivatives were also prepared and labeled with 125I and 211At. Oxidization of the [125I]iodo- and [211At]astato-benzamidyl-dPEG4-acid methyl ester derivatives provided materials for in vivo evaluation. A biodistribution was conducted in mice with coinjected oxidized 125I- and 211At-labeled compounds. The oxidized radioiodinated derivative was stable to in vivo deiodination, but unfortunately the oxidized [211At]astatinated benzamide derivative was found to be unstable under the conditions of isolation by radio-HPLC (post animal injection). Another biodistribution study in mice evaluated the tissue concentrations of coinjected [211At]NaAtO3 and [125I]NaIO3. Comparison of the tissue concentrations of the isolated material from the oxidized [211At]benzamide derivative with those of [211At]astatate indicated the species obtained after isolation was likely [211At]astatate.

59 BASIC BIOLOGICAL SCIENCES↗