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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Carbon recycling in materially closed ecological life support systems

Results of studies are presented of materially closed energetically open microbial ecosystems or 'closed ecosystems'. These are natural marine ecosystems that have been sealed in glass containers to prevent material exchange with the environment but allow energy to pass freely through them. They represent model life support systems for the future human habitation of space. The results are discussed analytically and indicate that these ecosystems, when subjected to a constant energy flux, seem to be reliable and self-sufficient systems for recycling of biologically produced carbon compounds.

Obenhuber, D. C.↗
NASA NTRS1989

Vega-Giotto flyby missions and cometary cosmogony

The most important implication of the Vega/Giotto flyby missions to Halley's Comet for cometary cosmogony is the opportunity to absorb the results of the in-situ measurements as made onboard the spacecrafts. Unfortunately the exploration of ejecta form the nucleus was unable to provide an unambiguous definition of the chemical-mineralogical nature of the nucleus: it failed to provide information comparable to that which was expected from a sample return mission. However, the obtained results are significant enough to affect and redirect cosmogonical thinking. Accordingly, the understanding of the cometary-matter dichotomy is modified as deduced from the distiction of water-dominated volitiles and silicate-based non-volitiles. Organic carbon compounds emerge as a major constituent of cometary nuclei. Presently, it is likely that the revision of Whipple's classic concept of the icy conglomerate cannot be avoided. Affected by the Vega/Giotto flyby missions to Hally's Comet, cometary cosmogony seems to enter a new conceptual period. The results of the in-situ measurements (mass spectrometric, UV spectroscopic, and IR spectroscopic) appear to be of basic importance. A chemical explanation is employed to explain the occurrence inside the nuclei of the variety of species, as inferred from the mass spectrometric data, to predict the results of the processes possibly involved. A cosmochemical factor is postulated to operate behind the observed cometary phenomena. The chemistry of the interstellar medium, covering the circumstellar and interstellar dust, advances cometary cosmogony.

Lang, Bruno↗
NASA NTRS1991

Characterization of low albedo asteroids

Three asteroid classes were defined from the early spectral surveys of the asteroids: C for carbonaceous, M for metallic, and S for stony. Subsequent spectral studies have defined new asteroid classes and have shown that the original classes can be divided into a number of additional asteroid types. The low albedo asteroids are now classified as types B, C, D, F, G, K and P. These types are concentrated in the middle asteroid belt and beyond. Their visible and near infrared spectra are generally featureless and dark, with a red slope in the ultraviolet. Some of them show water absorption features in the mid-infrared, indicating the presence of bound water. The lack of absorption features in the telescopic reflectance spectra has made it difficult to determine the mineralogy of the low albedo asteroids. Some of the asteroid spectra closely resemble laboratory spectra of carbonaceous chondrite meteorites, implying similar mineralogy. These meteorites are chemically primitive, composed of fine-grained matrix material which includes hydrous silicates, complex carbon compounds, olivine and pyroxene, combined with olivine and/or pyroxene chondrules. The main belt low albedo asteroids are probably very similar to these asteroids, but no meteoritic analogues exist for the most distant asteroid types.

Lebofsky, Larry A.↗
NASA NTRS1991

The states of carbon and nitrogen atoms after photodissociation of CN, CH, CH(+), C2, C3, and CO in comets

The photodissociation of carbon compounds by solar UV radiation at a heliocentric distance of 1 AU is examined, comparing published observational data with the predictions of theoretical models and results from laboratory experiments. It is shown that species other than CO, including CN, CH, CH(+), C2, and C3, can contribute to the observed brightness of the VUV lines of C I (156.1, 165.7, and 193.1 nm) and C II (133.5 nm) in comet comae. CN photodissociation is also found to produce metastable 2D0 and 2P0 N I atoms, possibly leading (at heliocentric distances less than 0.25 AU) to 143.9-nm emission via resonance fluorescence.

Singh, P. D.↗
NASA NTRS1991

Photochemical reactions of cyanoacetylene and dicyanoacetylene: Possible processes in Titan's atmosphere

Titan has an atmosphere which is subject to dramatic chemical evolution due mainly to the dramatic effect of the UV flux from the Sun. The energetic solar photons and other particles are converting the methane-nitrogen atmosphere into the unsaturated carbon compounds observed by the Voyager probes. These same solar photons are also converting some of these unsaturated reaction products into the aerosols observed in the atmosphere which obscure the view of the surface of Titan. In particular, the photochemical reactions of cyanoacetylene, dicyanoacetylene, acetylene and ethylene may result in the formation of the higher hydrocarbons and polymers which result in the aerosols observed in Titan's atmosphere. Polymers are the principal reaction products formed by irradiation of cyanoacetylene and dicyanoacetylene. Irradiation of cyanoacetylene with 185 nm of light also yields 1,3,5-tricyanobenzene while irradiation at 254 nm yields 1,2,4-tricyanobenzene and tetracyano cyclooctatetraenes. Photolyses of mixtures of cyanoacetylene and acetylene yields mono- and di- cyanobenzenes. The 1-Cyanocyclobutene is formed from the photochemical addition of cyanoacetylene with ethylene. The photolysis of dicyanoacetylene with acetylene yields 2,3-dicyano-1,3-butadiene and 1,2-dicyanobenzene. Tetracyano cyclooctatetraene products were also observed in the photolysis of mixtures of dicyanoacetylene and acetylene with 254 nm light. The 1,2-Dicyano cyclobutene is obtained from the photolysis dicyanoacetylene and ethylene. Reaction mechanisms will be proposed to explain the observed photoproducts.

Ferris, J. P.↗
NASA NTRS1993

Theoretical calculations on the electron absorption spectra of selected Polycyclic Aromatic Hydrocarbons (PAH) and derivatives

As a theoretical component of the joint effort with the laboratory of Dr. Lou Allamandola to search for potential candidates for interstellar organic carbon compound that are responsible for the visible diffuse interstellar absorption bands (DIB's), quantum mechanical calculations were performed on the electron absorption spectra of selected polycyclic aromatic hydrocarbons (PAH) and derivatives. In the completed project, 15 different species of naphthalene, its hydrogen abstraction and addition derivatives, and corresponding cations and anions were studied. Using semiempirical quantum mechanical method INDO/S, the ground electronic state of each species was evaluated with restricted Hartree-Fock scheme and limited configuration interaction. The lowest energy spin state for each species was used for electron absorption calculations. Results indicate that these calculations are accurate enough to reproduce the spectra of naphthalene cation and anion observed in neon matrix. The spectral pattern of the hydrogen abstraction and addition derivatives predicted based on these results indicate that the electron configuration of the pi orbitals of these species is the dominant determinant. A combined list of 19 absorptions calculated from 4500 A to 10,400 A were compiled and suggested as potential candidates that are relevant for the DIB's absorptions. Continued studies on pyrene and derivatives revealed the ground state symmetries and multiplicities of its neutral, anionic, and cationic species. Spectral calculations show that the cation (B(sub 3g)-2) and the anion (A(sub u)-2) are more likely to have low energy absorptions in the regions between 10 kK and 20 kK, similar to naphthalene. These absorptions, together with those to be determined from the hydrogen abstraction and addition derivatives of pyrene, can be used to provide additional candidates and suggest experimental work in the search for interstellar compounds that are responsible for DIB's.

Du, Ping↗
NASA NTRS1994

The Diffuse Interstellar Bands: Contributed papers

Drawing a coherent picture of the observational characteristics of the Diffuse Interstellar Bands (DIB's) and the physical and chemical properties of its proposed carriers was the focus of this NASA sponsored conference. Information relating to absoption spectra, diffuse radiation carriers, carbon compounds, stellar composition, and interstellar extinction involving T-Tauri stars, Reflection Nebulae, Red Giants, and accretion discs are discussed from those papers presented at the conference, which are included in this analytic.

Tielens, Alexander G. G. M.↗
NASA NTRS1999

Synthesis of Large Molecules in Cometary Ice Analogs: Physical Properties Related to Self-Assembly Processes

The combination of realistic laboratory simulations and infrared observations have revolutionized our understanding of interstellar dust and ice-the main component of comets. Since comets and carbonaceous micrometeorites may have been important sources of volatiles and carbon compounds on the early Earth, their organic composition may be related to the origin of life. Ices on grains in molecular clouds contain a variety of simple molecules. The D/H ratios of the comets Hale-Bopp and Hyakutake are consistent with a primarily interstellar ice mixture. Within the cloud and especially in the presolar nebula through the early solar system, these icy grains would have been photoprocessed by the ultraviolet producing more complex species such as hexamethylenetetramine, polyoxymethylenes, and simple keones. We reported at the 1999 Bioastronomy meeting laboratory simulations studied to identify the types of molecules which could have been generated in pre-cometary ices. Experiments were conducted by forming a realistic interstellar mixed-molecular ice (H2O, CH3OH, NH3 and CO) at approximately 10 K under high vacuum irradiated with UV light from a hydrogen plasma lamp. The gas mixture was typically 100:50:1:1, however when different ratios were used material with similar characteristics was still produced. The residue that remained after warming to room temperature was analyzed by HPLC, and by several mass spectrometric methods. This material contains a rich mixture of complex compounds with mass spectral profiles resembling those found in IDPs and meteorites. Surface tension measurements show that an amphiphilic component is also present. These species do not appear in various controls or in unphotolyzed samples. Residues from the simulations were also dispersed in aqueous media for microscopy. The organic material forms 10-40 gm diameter droplets that fluoresce at 300-450 nm under UV excitation. These droplets have a morphology and internal structure which appear strikingly similar to those produced by extracts of the Murchison meteorite. Together, these results suggest a link between organic material photochemically synthesized on the cold grains in dense, interstellar molecular clouds and compounds that may have contributed to the organic inventory of the primitive Earth. For example, the amphiphilic properties of such compounds permit self-assembly into the membranous boundary structures that required for the first forms of cellular life.

Dworkin, Jason P.↗
NASA NTRS2013

Low-Energy, Hydrogen-Free Method of Diamond Synthesis

Diamond thin films were deposited on copper substrate by the Vapor Solid (VS) deposition method using a mixture of fullerene C(sub 60) and graphite as the source material. The deposition took place only when the substrate was kept in a narrow temperature range of approximately 550-650 C. Temperatures below and above this range results in the deposition of fullerenes and other carbon compounds, respectively.

Varshney, Deepak↗
NASA NTRS2016

Amino Acids in the Asteroidal Water-Bearing Salt Crystals Hosted in the Zag Meteorite

Solid evidence of liquid water in primitive meteorites is given by the ordinary chondrites H5 Monahans (1998) and H3-6 Zag. Aqueous fluid inclusion-bearing halite (NaCl) crystals were shown to be common in Zag. These striking blue/purple crystals (Figure 1), which gained the coloration from electron-trapping in the Cl-vacancies through exposure to ionizing radiation, were determined to be over 4.0-4.7 billion years old by I-Xe dating. The halite grains are present as discrete grains within an H-chondrite matrix with no evidence for aqueous alteration that indicates a xenogenic source, possibly ancient cryovolcanism. They were proposed to be formed from the cryovolcanic plumes on icy C-type asteroids (possibly Ceres), and were transferred and incorporated into the H chondrite parent asteroid following the eruption event(s). A unique aspect of these halites is that they contain abundant solid inclusions hosted within the halites alongside the water inclusions. The solid inclusions were suggested to be entrained within the fluid erupted from the cryovolcanic event(s), and were shown to be comprised of abundant organics. Spectrofluorometric study and Raman imaging of the halites have identified macromolecular carbon and aliphatic carbon compounds. In order to investigate the type of organics present in Zag and in particular within the fluid-bearing halites, we studied for the first time the amino acid contents of a selected mineral (halite) phase in a meteorite sample.

Chan, Q. H. S.↗
NASA NTRS2016

Tropospheric Ozone Change from 1980 to 2010 Dominated by Equatorward Redistribution of Emissions

Ozone is an important air pollutant at the surface, and the third most important anthropogenic greenhouse gas in the troposphere. Since 1980, anthropogenic emissions of ozone precursors methane, non-methane volatile organic compounds, carbon monoxide and nitrogen oxides (NOx) have shifted from developed to developing regions. Emissions have thereby been redistributed equatorwards, where they are expected to have a stronger effect on the tropospheric ozone burden due to greater convection, reaction rates and NOx sensitivity. Here we use a global chemical transport model to simulate changes in tropospheric ozone concentrations from 1980 to 2010, and to separate the influences of changes in the spatial distribution of global anthropogenic emissions of short-lived pollutants, the magnitude of these emissions, and the global atmospheric methane concentration. We estimate that the increase in ozone burden due to the spatial distribution change slightly exceeds the combined influences of the increased emission magnitude and global methane. Emission increases in Southeast, East and South Asia may be most important for the ozone change, supported by an analysis of statistically significant increases in observed ozone above these regions. The spatial distribution of emissions dominates global tropospheric ozone, suggesting that the future ozone burden will be determined mainly by emissions from low latitudes.

Zhang, Yuqiang↗
NASA NTRS2015

3D Photocatalytic Air Processor for Dramatic Reduction of Life Support Mass and Complexity

To dramatically reduce the cost and risk of CO2 management systems in future extended missions, we have conducted preliminary studies on the materials and device development for advanced "artificial photosynthesis" reaction systems termed the High Tortuosity PhotoElectroChemical (HTPEC) system. Our Phase I studies have demonstrated that HTPEC operates in much the same way a tree would function, namely directly contacting the cabin air with a photocatalyst in the presence of light and water (as humidity) to immediately conduct the process of CO2 reduction to O2 and useful, "tunable" carbon products. This eliminates many of the inefficiencies associated with current ISS CO2 management systems. We have laid the solid foundation for Phase II work to employ novel and efficient reactor geometries, lighting approaches, 3D manufacturing methods and in-house grown novel catalytic materials.The primary objective of the proposed work is to demonstrate the scientific and engineering foundation for light-activated, compact devices capable of converting CO2 to O2 and mission-relevant carbon compounds. The proposed HTPEC CO2 management system will demonstrate a novel pathway with high efficiency and reliability in a compact, lightweight reactor architecture. The proposed HTPEC air processing concept can be developed in multiple architectures, such as centralized processing as well as "artificial leaves" distributed throughout the cabin that utilize pre-existing cabin ventilation (wind). Additionally, HTPEC can be deployed with spectrally tunable collection channels for selectable product generation. HTPEC employs light as its only energy source to remove and convert waste CO2 using a non-toxic composite catalyst.We have demonstrated in the Phase I studies the production, tunability and robustness of the novel composite catalysts following the preliminary work in the Chen laboratory. Additionally, we have designed, fabricated and tested all components of HTPEC device with active materials, including flow modeling to optimize flow mixing and pressure drop as well as the production of ethylene and other larger hydrocarbons. To best determine how this technology could be implemented, we also performed system integration optimization and trade studies. This includes parameters such as mass, volume, power in relation to selected mission configurations, CO2 delivery methods and light source/delivery approaches.

Artificial Photosynthesis↗
NASA NTRSDate not supplied

A Drilling Mission to Search for Biosignatures of Life on Mars Simulated in Atacama Chile

Missions to search for evidence of life on Mars, including Mars Science Laboratory(MSL)are using drilling systems to get beneath the high oxidized and radiated surface where biomolecules may be preserved. MSL drill holes show that even at shallow depth the subsurface is more reduced and therefor more likely to preserve biosignatures. Analysis of these reduced materials yielded the first detection of organic carbon compounds on Mars[1].While MSL was capable of drilling only 10 cm, the ExoMars mission now planned for a 2022 launch will feature a rover carrying a 2 m drill, motivated by desire to penetrate beneath the irradiated surface. The Atacama Rover Astrobiology Drilling Studies(ARADS)was a PSTAR project that used flight prototype technologies in a highly relevant Mars analog site, together with related scientific studies, to better understand how to best search for life on Mars. ARADS field work was performed in Atacama Chile and featured a rover-mounted 1.2m auguring drill to acquire subsurface samples that were analyzed with flight prototype instruments designed to search for chemical signatures of life.

C R Stoker↗
NASA NTRS2023

Satellite Remote-Sensing Capability to Assess Tropospheric-Column Ratios of Formaldehyde and Nitrogen Dioxide: Case Study During the Long Island Sound Tropospheric Ozone Study 2018 (LISTOS 2018) Field Campaign

Satellite retrievals of tropospheric-column formaldehyde (HCHO) and nitrogen dioxide (NO 2 ) are frequently used to investigate the sensitivity of ozone (O 3 ) production to emissions of nitrogen oxides and volatile organic carbon compounds. This study inter-compared the systematic biases and uncertainties in retrievals of NO 2 and HCHO, as well as resulting HCHO–NO 2 ratios (FNRs), from two commonly applied satellite sensors to investigate O 3 production sensitivities (Ozone Monitoring Instrument, OMI, and TROPOspheric Monitoring Instrument, TROPOMI) using airborne remote-sensing data taken during the Long Island Sound Tropospheric Ozone Study 2018 between 25 June and 6 September 2018. Compared to aircraft-based HCHO and NO 2 observations, the accuracy of OMI and TROPOMI were magnitude-dependent with high biases in clean environments and a tendency towards more accurate comparisons to even low biases in moderately polluted to polluted regions. OMI and TROPOMI NO 2 systematic biases were similar in magnitude (normalized median bias, NMB = 5 %–6 %; linear regression slope ≈ 0.5–0.6), with OMI having a high median bias and TROPOMI resulting in small low biases. Campaign-averaged uncertainties in the three satellite retrievals (NASA OMI; Quality Assurance for Essential Climate Variables, QA4ECV OMI; and TROPOMI) of NO 2 were generally similar, with TROPOMI retrievals having slightly less spread in the data compared to OMI. The three satellite products differed more when evaluating HCHO retrievals. Campaign-averaged tropospheric HCHO retrievals all had linear regression slopes ∼0.5 and NMBs of 39 %, 17 %, 13 %, and 23 % for NASA OMI, QA4ECV OMI, and TROPOMI at finer (0.05° x 0.05°) and coarser (0.15° x 0.15°) spatial resolution, respectively. Campaign-averaged uncertainty values (root mean square error, RMSE) in NASA and QA4ECV OMI HCHO retrievals were ~9.0 x 10 15 molecules cm –2 (∼ 50 %–55 % of mean column abundance), and the higher-spatial-resolution retrievals from TROPOMI resulted in RMSE values ∼30 % lower. Spatially averaging TROPOMI tropospheric-column HCHO, along with NO 2 and FNRs, to resolutions similar to the OMI reduced the uncertainty in these retrievals. Systematic biases in OMI and TROPOMI NO 2 and HCHO retrievals tended to cancel out, resulting in all three satellite products comparing well to observed FNRs. However, while satellite-derived FNRs had minimal campaign-averaged median biases, unresolved errors in the indicator species did not cancel out in FNR calculations, resulting in large RMSE values compared to observations. Uncertainties in HCHO retrievals were determined to drive the unresolved biases in FNR retrievals.

Matthew S. Johnson↗
NASA NTRS1972

Solid amine compounds as sorbents for carbon dioxide: A concept

Solid amine compounds were examined as possible absorbents for removal of carbon dioxide in life support systems of type which may be employed in high altitude aircraft, spacecraft, or submarines. Many solid amine compounds release absorbed carbon dioxide when heated in vacuum, therefore, when properly packaged spent amine compounds can be readily regenerated and put back into service.

Sutton, J. G.↗
DOE OSTI2024

Wholly Sustainable, Cost-Effective Carbon Fiber-Nylon Compounds CRADA 592 (Final Report)

Carbon fiber composites have attracted considerable attention due to the potential for substantial mass savings, with many examples now implemented in the low-volume luxury car market. However, migration to higher volume applications has been hindered by: (a) high material cost, (b) high processing times, and (c) perception of low Sustainability. This project will address all three of these barriers: (a) carbon fiber material to replace aluminum in structural components at a cost penalty of no more than $5/Kg-saved (aka weight buy), (b) fitting into high-rate processes for automotive production like injection molding, and (c) end-to-end Sustainable material – based on post industrial waste carbon fiber and nylon 66 and ability to recycle end-of-life auto parts. The opportunity lies in combining DowAksa capabilities in carbon fiber manufacturing, resin chemistry intermediate production with the unique testing capabilities inherent within PNNL. The teams from PNNL and DowAksa held several meetings virtually and in-person in Michigan and at PNNL, including a lab tour at PNNL. Throughout, the teams discussed DowAksa material sources, commercially available recycled base materials, and preliminary material properties. The teams also engaged in multiple discussions and evaluations of potential automotive applications based on the ideas suggested by PNNL. The teams discussed several potential automotive applications in which recycled carbon fiber and recycled PA resin can be used. The PNNL team identified 38 cast aluminum components that can potentially be assessed for redesign using the DowAksa materials system. The PNNL team also identified 27 polyamide components. The teams discussed the lists and narrowed it down to a handful of applications that are exterior and interior to common vehicle architectures. The team also considered semi-structural and structural components and short-listed the highest potential candidates, such as cross-car-beam. The cross-car beam was considered to be highly suitable and potentially viable demonstration applications based on the properties of the materials as well as the weight savings potentials and the reduction in embodied energy by utilizing wholly sustainable materials, since both materials, carbon fiber and resin, were derived from recycled materials. The next step was to reach out to potential OEMs and/or Tier1s who were interested in exploring such technology for future applications. However, the project was terminated, and no further discussions or exchange of information took place. No new data were generated, including no IP and no publications.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Validation of process simulation workflow for thermosetting prepreg platelet molding compounds

Continuous carbon fiber prepreg slit and cut into rectangular platelets has proven to be a useful material for net shape molding of semi-structural and structural components in the aerospace and automotive industries. Furthermore, to assist the designer in use of these prepreg platelet molding compounds, sometimes called carbon fiber sheet molding compounds, simulation tools are required that can predict the as-manufactured fiber orientation state which has a significant impact on the resulting performance. Herein, an analysis workflow for design-enabling predictions is demonstrated for a double dome geometry with two different initial charge configurations. Here, the workflow is validated through comparison with experimental short shots, orientation state, and stiffness trends. Significantly, to complete the validation, a method is proposed for determining the confidence bounds on measured orientation state enhancing the results of optical microscopy which can only produce a small sample of platelet orientations.

36 MATERIALS SCIENCE↗