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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 NTRS2009

NASA Materials Research for Extreme Conditions

This Technical Memorandum briefly covers various innovations in materials science and development throughout the course of the American Space program. It details each innovation s discovery and development, explains its significance, and describes the applications of this material either in the time period discovered or today. Topics of research include silazane polymers, solvent-resistant elastomeric polymers (polyurethanes and polyisocyanurates), siloxanes, the Space Shuttle thermal protection system, phenolic-impregnated carbon ablator, and carbon nanotubes. Significance of these developments includes the Space Shuttle, Apollo programs, and the Constellation program.

Sharpe, R. J.↗
NASA NTRS2011

Low temperature double-layer capacitors

Double-layer capacitors capable of operating at extremely low temperatures (e.g., as low as -75.degree. C.) are disclosed. Electrolyte solutions combining a base solvent (e.g., acetonitrile) and a cosolvent are employed to lower the melting point of the base electrolyte. Example cosolvents include methyl formate, ethyl acetate, methyl acetate, propionitrile, butyronitrile, and 1,3-dioxolane. An optimized concentration (e.g., 0.10 M to 0.75 M) of salt, such as tetraethylammonium tetrafluoroborate, is dissolved into the electrolyte solution. In some cases (e.g., 1,3-dioxolane cosolvent) additives, such as 2% by volume triethylamine, may be included in the solvent mixture to prevent polymerization of the solution. Conventional device form factors and structural elements (e.g., porous carbon electrodes and a polyethylene separator) may be employed.

Brandon, Erik J.↗
NASA NTRS1981

Physical aging of linear and network epoxy resins

Network and linear epoxy resins principally based on the diglycidyl ether of bisphenol-A and its oligomers are prepared and studied using diamine and anhydride crosslinking agents. Rubber modified epoxies and a carbon fiber reinforced composite are also investigated. All materials display time-dependent changes when stored at temperatures below the glass transition temperature after quenching (sub-T/g/ annealing). Solvent sorption experiments initiated after different sub-T(g) annealing times demonstrate that the rate of solvent uptake can be indirectly related to the free volume of the epoxy resins. Residual thermal stresses and water are found to have little effect on the physical aging process, which affects the sub-T(g) properties of uniaxial carbon fiber reinforced epoxy material. Finally, the importance of the recovery phenomenon which affects the durability of epoxy glasses is considered.

Kong, E. S.-W.↗
NASA NTRS1972

Microbial degradation of parathion

An organism capable of utilizing parathion as the sole carbon and energy source was isolated by enrichment culture techniques. The bacterium was characterized and tentatively classified as Pseudomonas aeruginosa. A pH of 7.0 - 7.5 and temperature of 30 C were found to be optimum for the consumption of parathion. Virtually no oxygen utilization was observed with resting cell suspensions when nonsolubilized parathion was employed. The use of ethanol as solvent for parathion in resting cell studies or preincubation of cells in ethanol obviated this problem and rapid parathion oxidation was demonstrable. Approximately 80% of the parathion consumed by resting cells was present terminally as carbon dioxide. Permeability of the cell to parathion or its metabolites was contingent upon the use of ethanol as either solvent or denaturant. Metabolites were tentatively identified by thin layer chromatography.

Gibson, W. L.↗
NASA NTRS2004

Growth of Multi-Walled Carbon Nanotubes by Injection CVD Using Cyclopentadienyliron Dicarbonyl Dimer and Cyclooctatetraene Iron Tricarbonyl

Preferential oriented multiwalled carbon nanotubes were prepared by the injection chemical vapor deposition (CVD) method using either cyclopentadienyliron dicarbonyl dimer or cycloctatetraene iron tricarbonyl as the iron catalyst source. The catalyst precursors were dissolved in toluene as the carrier solvent for the injections. The concentration of the catalyst was found to influence both the growth of the nanotubes as well as the amount of iron in the deposited material. As deposited the multiwalled carbon nanotubes contained as little as 2.8% iron by weight. The material was deposited onto tantalum foil and fused silica substrates. The nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and thermogravimetric analysis. This synthetic route provides a simple and scalable method to deposit MWNTs with a low defect density, low metal content and preferred orientation.

Harris, Jerry D.↗
NASA NTRS2010

NASA-JSC Protocol for the Characterization of Single Wall Carbon Nanotube Material Quality

It is well known that the raw as well as purified single wall carbon nanotube (SWCNT) material always contain certain amount of impurities of varying composition (mostly metal catalyst and non-tubular carbon). Particular purification method also creates defects and/or functional groups in the SWCNT material and therefore affects the its dispersability in solvents (important to subsequent application development). A number of analytical characterization tools have been used successfully in the past years to assess various properties of nanotube materials, but lack of standards makes it difficult to compare these measurements across the board. In this work we report the protocol developed at NASA-JSC which standardizes measurements using TEM, SEM, TGA, Raman and UV-Vis-NIR absorption techniques. Numerical measures are established for parameters such as metal content, homogeneity, thermal stability and dispersability, to allow easy comparison of SWCNT materials. We will also report on the recent progress in quantitative measurement of non-tubular carbon impurities and a possible purity standard for SWCNT materials.

Arepalli, Sivaram↗
NASA NTRS1994

Waste gas storage

Method for storing a waste gas mixture comprised of nitrogen, oxygen, carbon dioxide, and inert gases, the gas mixture containing corrosive contaminants including inorganic acids and bases and organic solvents, and derived from space station operations. The gas mixture is stored under pressure in a vessel formed of a filament wound composite overwrap on a metal liner, the metal liner being pre-stressed in compression by the overwrap, thereby avoiding any tensile stress in the liner, and preventing stress corrosion cracking of the liner during gas mixture storage.

Vickers, Brian D.↗
NASA NTRS2024

Organic Products of Fatty Acid and Magnesium Sulfate Mixtures after Gamma Radiolysis: Implications for Missions to Europa

If ocean-derived materials are present at Europa’s surface, they would represent accessible records of ocean chemistry and habitability, but such materials would be further processed by the moon’s harsh radiation environment. In this study, saturated fatty acids were precipitated onto a Europa-relevant hydrated magnesium sulfate and exposed to gamma radiation doses up to 2 MGy at -196° C. Alkane chains, with carbon numbers one less than those of the starting fatty acids, were the most abundant radiolysis products in solvent and thermal extracts analyzed by gas chromatography mass spectrometry. Detections of monounsaturated fatty acids and combined radiolysis products were attributed to the experiment’s Europa-like parameters. Additionally, elevated concentrations of shorter-chain saturated fatty acids suggest that gamma radiation induced charge remote fragmentation of the alkyl chains of some starting fatty acids under these experimental conditions. Quantitation of fatty acid concentrations in the irradiated samples enabled the calculation of a radiolysis constant that indicated exposure to a 5 MGy dose of gamma radiation would have resulted in a ~90% loss of the initial fatty acid population. The samples were further studied by Raman spectroscopy and laser desorption and ionization mass spectrometry, which characterized the distribution of fatty acids and their radiolysis products on sulfate surfaces. The substantial loss of starting fatty acids typically seen with increasing radiation dose, along with the remarkable diversity of radiolysis products identified, suggest that the detection of fatty acids in irradiated sulfate deposits on Europa will be challenged by rapid destruction of any initial fatty acid populations and scrambling of their residual signals by a myriad of organic radiolysis products. If missions to Europa encounter sulfate deposits, targeting minimally irradiated units may still enable the detection of surviving fatty acid signatures that could inform about Europa’s subsurface chemistry and habitability.

James M T Lewis↗
NASA NTRS2003

New Method Developed To Purify Single Wall Carbon Nanotubes for Aerospace Applications

Single wall carbon nanotubes have attracted considerable attention because of their remarkable mechanical properties and electrical and thermal conductivities. Use of these materials as primary or secondary reinforcements in polymers or ceramics could lead to new materials with significantly enhanced mechanical strength and electrical and thermal conductivity. Use of carbon-nanotube-reinforced materials in aerospace components will enable substantial reductions in component weight and improvements in durability and safety. Potential applications for single wall carbon nanotubes include lightweight components for vehicle structures and propulsion systems, fuel cell components (bipolar plates and electrodes) and battery electrodes, and ultra-lightweight materials for use in solar sails. A major barrier to the successful use of carbon nanotubes in these components is the need for methods to economically produce pure carbon nanotubes in large enough quantities to not only evaluate their suitability for certain applications but also produce actual components. Most carbon nanotube synthesis methods, including the HiPCO (high pressure carbon monoxide) method developed by Smalley and others, employ metal catalysts that remain trapped in the final product. These catalyst impurities can affect nanotube properties and accelerate their decomposition. The development of techniques to remove most, if not all, of these impurities is essential to their successful use in practical applications. A new method has been developed at the NASA Glenn Research Center to purify gram-scale quantities of single wall carbon nanotubes. This method, a modification of a gas phase purification technique previously reported by Smalley and others, uses a combination of high-temperature oxidations and repeated extractions with nitric and hydrochloric acid. This improved procedure significantly reduces the amount of impurities (catalyst and nonnanotube forms of carbon) within the nanotubes, increasing their stability significantly. The onset of decomposition of the purified nanotubes (determined by thermal gravimetric analysis in air) is more than 300 C higher than that of the crude nanotubes. Transmission electron microscopy analysis of nanotubes purified by this method reveals near complete removal of iron catalyst particles. Analysis of the nanotubes using inductively coupled plasma spectroscopy revealed that the iron content of the nanotubes was reduced from 22.7 wt% in the crude nanotubes to less than 0.02 wt%. X-ray photoelectron spectroscopy revealed a decrease in iron content after purification as well as an increase in oxygen content due to the formation of carboxylic acid groups on the surface of the nanotubes. Nanotubes purified by this improved method can be readily dispersed in common organic solvents, in particular N,N-dimethylformamide, using prolonged ultrasonic treatment. These dispersions can then be used to incorporate single wall carbon nanotubes into polymer films.

Lebron, Marisabel↗
NASA NTRS2009

From Bench Top to Market: Growth of Multi-Walled Carbon Nanotubes by Injection CVD Using Fe Organometallics - Production of a Commercial Reactor

Preferential oriented multiwalled carbon nanotubes were prepared by the injection chemical vapor deposition (CVD) method using either cyclopentadienyliron dicarbonyl dimer or cyclooctatetraene iron tricarbonyl as the iron catalyst source. The catalyst precursors were dissolved in toluene as the carrier solvent for the injections. The concentration of the catalyst was found to influence both the growth (i.e., MWNT orientation) of the nanotubes, as well as the amount of iron in the deposited material. As deposited, the multiwalled carbon nanotubes contained as little as 2.8% iron by weight. The material was deposited onto tantalum foil and fused silica substrates. The nanotubes were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy and thermogravimetric analysis. This synthetic route provides a simple and scalable method to deposit MWNTs with a low defect density, low metal content and a preferred orientation. Subsequently, a small start-up was founded to commercialize the deposition equipment. The contrast between the research and entrepreneurial environments will be discussed.

Rowsell, J.↗
NASA NTRS1989

Interior Landscape Plants for Indoor Air Pollution Abatement

In this study, the leaves, roots, soil, and associated microorganisms of plants have been evaluated as a possible means of reducing indoor air pollutants. Additionally, a novel approach of using plant systems for removing high concentrations of indoor air pollutants such as cigarette smoke, organic solvents, and possibly radon has been designed from this work. This air filter design combines plants with an activated carbon filter. The rationale for this design, which evolved from wastewater treatment studies, is based on moving large volumes of contaminated air through an activated carbon bed where smoke, organic chemicals, pathogenic microorganisms (if present), and possibly radon are absorbed by the carbon filter. Plant roots and their associated microorganisms then destroy the pathogenic viruses, bacteria, and the organic chemicals, eventually converting all of these air pollutants into new plant tissue. It is believed that the decayed radon products would be taken up the plant roots and retained in the plant tissue.

Wolverton, B. C.↗
NASA NTRS2005

Valiant 'Zero-Valent' Effort Restores Contaminated Grounds

Dense non-aqueous phase liquids (DNAPLs) are chemical compounds that can contaminate soil and groundwater to the point of irreparability. These substances are only slightly soluble in water, and are much denser than water. Because of their solubility, DNAPLs form separate liquid phases in groundwater, and because of their density, DNAPLs sink in aquifers instead of floating at the water table, making it extremely difficult to detect their presence. If left untreated in the ground, they can taint fresh water sources. Common DNAPLs include chlorinated hydrocarbon compounds such as carbon tetrachloride, chloroform, tetrachloroethylene, and trichloroethylene. Trichloroethylene was used during the early days of the Space Program, as a solvent for flushing rocket engines, and for metal cleaning and degreasing of equipment, electronics, and heavy machinery. As a result, areas of Cape Canaveral s Launch Complex 34, the site of several historic Saturn rocket launches occurring from 1959 to 1968, were polluted with chlorinated DNAPLs. Through the direction and guidance of Dr. Jacqueline Quinn, an environmental engineer in the Spaceport Engineering and Technology Directorate at NASA s Kennedy Space Center, a biodegradable environmental cleanup technology was developed to reductively dechlorinate DNAPL sources in polluted water at Launch Complex 34. It was important for Kennedy to nip this problem in the bud, in light of the fact that the Space Center is also a National Wildlife Refuge, home to thousands of shorebirds, endangered sea turtles and eagles, manatees, alligators, and diverse habitats that include brackish marshes and salt water estuaries. The success in remediating this historic launch site has led to numerous commercial applications that are restoring the health of our environmental surroundings.

Source record↗
NASA NTRS2014

A Five-year Performance Study of Low VOC Coatings over Zinc Thermal Spray for the Protection of Carbon Steel at the Kennedy Space Center

The launch facilities at the Kennedy Space Center (KSC) are located approximately 1000 feet from the Atlantic Ocean where they are exposed to salt deposits, high humidity, high UV degradation, and acidic exhaust from solid rocket boosters. These assets are constructed from carbon steel, which requires a suitable coating to provide long-term protection to reduce corrosion and its associated costs. While currently used coating systems provide excellent corrosion control performance, they are subject to occupational, safety, and environmental regulations at the Federal and State levels that limit their use. Many contain high volatile organic compounds (VOCs), hazardous air pollutants, and other hazardous materials. Hazardous waste from coating operations include vacuum filters, zinc dust, hazardous paint related material, and solid paint. There are also worker safety issues such as exposure to solvents and isocyanates. To address these issues, top-coated thermal spray zinc coating systems were investigated as a promising environmentally friendly corrosion protection for carbon steel in an acidic launch environment. Additional benefits of the combined coating system include a long service life, cathodic protection to the substrate, no volatile contaminants, and high service temperatures. This paper reports the results of a performance based study to evaluate low VOC topcoats (for thermal spray zinc coatings) on carbon steel for use in a space launch environment.

Zinc Thermal Spray↗
NASA NTRS1995

Poly(N-arylenbenzimidazoles) via aromatic nucleophilic displacement

Novel poly(N-arylenebenzimidazole)s (PNABIs) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl N-arylenebenzimidazole) monomers are synthesized by reacting phenyl 4-hydroxybenzoate with bis(2-aminoanilino) arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyl N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Connell, John W.↗
NASA NTRS1995

Polybenzimidazoles via aromatic nucleophilic displacement

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl) benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl) benzimidazoles are synthesizedby reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W.↗
NASA NTRS1997

Polybenzimidazoles Via Aromatic Nucleophilic Displacement

Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

Connell, John W.↗
NASA NTRS1996

Poly(N-arylenebenzimidazole)s via aromatic nucleophilic displacement

Novel poly(N-arylenebenzimidazole)s (PNABls) are prepared by the aromatic nucleophilic displacement reaction of novel di(hydroxyphenyl-N-arylene benzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl-N-arylenebenzimidazole) monomers are synthesized by reacting phenyl-4-hydroxybenzoate with bis(2-aminoanilino)arylenes in diphenylsulfone. Moderate molecular weight PNABIs of new chemical structures were prepared that exhibit a favorable combination of physical and mechanical properties. The use of the novel di(hydroxyphenyI-N-arylenebenzimidazole)s permits a more economical and easier way to prepare PNABIs than previous routes.

Connell, John W.↗
NASA NTRS1993

FTIR quantification of industrial hydraulic fluids in perchloroethylene

The purpose of this summer research project was to investigate whether perchloroethylene can be used as a solvent for the quantitative analysis of industrial hydraulic fluids by infrared spectroscopy employing Beer's law. Standard calibration curves using carbon-hydrogen stretching (generic) and ester absorption peaks were prepared for a series of standard dilutions at low ppm levels of concentration of seven hydraulic fluids in perchloroethylene. The absorbance spectras were recorded with 1.5-10 mm fixed and variable path length sample cells made of potassium bromide. The results indicate that using ester infrared spectral peak, it is possible to detect about 20 ppm of the hydraulic fluid in perchloroethylene.

Mehta, Narinder K.↗