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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Growth and development in inert non-aqueous liquids

A preview is presented of the survival and growth capabilities of higher plants in non-aqueous, inert liquids. The two media which were used are mineral (white) oil and fluorochemical inert liquid FC-75. Both liquids dissolve oxygen and carbon dioxide readily, but are insoluble in water. Consequently, plants submerged in these liquids are capable of gas exchange with the atmosphere, but possess a water impermeable coating the dimensions of which are determined by the size of the liquid holding container. In a sense, growing plants in a tank of mineral oil imparts on them a cuticle. Plants plus prescribed volumes of water were innoculated into mineral oil. Organisms with minimal water supplied could then be observed. Also, submersed plants covered with an oil slick were shown to be capable of growth in dessicating atmospheres.

Siegel, S. M.↗
NASA NTRS1994

Non-aqueous cleaning solvent substitution

A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of AlliedSignal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, was selected as the solvent of choice, and it was found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally-safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

Meier, Gerald J.↗
NASA NTRS1983

The electrochemical fluorination of polymeric materials for high energy density aqueous and non-aqueous battery and fuel cell separators

A computerized system was established and the electrochemical fluorination of trichloroethylene, polyacrylic acid and polyvinyl alcohol in anhydrous hydrogen fluoride was attempted. Both solid substrates as well as membranes were used. Some difficulties were found in handling and analyzing the solid substrates and membranes. Further studies are needed in this area. A microprocessor aided electrochemical fluorination system capable of obtaining highly reproducible experimental results was established.

Liu, C. C.↗
NASA NTRS1992

Carbonate formation on Mars: History of the CO2 atmosphere from models of diffusion-limited growth in non-aqueous environments

We conducted preliminary experiments designed to measure the amount of CO2 reacted from a simulated Martian atmosphere to form carbonate on silicate grains. Warm experiments at constant T (300-350 K) and with no water (vapor or liquid) yielded no detectable reaction, suggesting the following result. If we are indeed operating in the thermodynamically-favorable regime (supported by Gooding (1978) for the gas-solid reaction), then the lack of a reaction at warm temperatures suggests that a reaction in the 200-300 K regime will be less favored if reaction kinetics dominate. The completely dry scenario is thus not favored. An additional experiment, with abundant water vapor and at T approx. 300 K (constant), yielded a negative result as well. However, this is not inconsistent with Booth's findings, since lower temperatures may be required for the absorption of a monolayer of water. We plan further (lower-T) experiments.

Stephens, Stuart K.↗
NASA NTRS1992

Room temperature synthesis of copper indium diselenide in non-aqueous solution using an organoindium reagent

A novel two-phase synthesis of CuInSe2 at 25 C from Cu2Se and Cp3In in 4-methylpyridine has been discovered. Characterization of the material produced shows it to be platelet-shaped crystallites with an average particle size of 10 microns, less than 2 percent C and H, with a small amount of unidentified crystalline impurity. The results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons. The use of a solid-state reagent as a starting material which is converted to another solid-state compound by an organometallic reagent has tremendous potential to produce precursors for a wide range of solid-state materials of interest to the electronics, defense, and aerospace communities.

Hepp, Aloysius F.↗
NASA NTRS1994

Room-temperature synthesis of CuInQ2 (Q = S or Se) in non-aqueous solution using an organoindium reagent

We have discovered a novel two-phase synthesis of CuInSe2 at 25 deg C from Cu2Se and (C5H5)3In in 4-methylpyridine (4-MePy). An analogous reaction to produce CuInS2 must be run at 140 deg C in refluxing 4-MePy in the presence of 2-mercaptopyridine. Microscopy of CuInSe2 produced at 25 deg C shows it to be platelet-shaped crystallites with an approximate particle size of 10 microns, less than 2 percent C and H, with a small amount of unidentified crystalline impurity. Our results demonstrate that it is possible to produce from solution a material that is ordinarily synthesized in bulk or films at much higher temperatures or using extraneous reagents and/or electrons.

Hepp, Aloysius F.↗
NASA NTRS1991

Mixed solvent electrolytes for ambient temperature secondary lithium cells

The present invention comprises an improved electrolyte for secondary lithium-based cells as well as batteries fabricated using this electrolyte. The electrolyte is a lithium containing salt dissolved in a non-aqueous solvent, which is made from a mixture of ethylene carbonate, ethylene propylene diene terpolymer, 2-methylfuran, and 2-methyltetrahydrofuran. This improved, mixed solvent electrolyte is more conductive than prior electrolytes and much less corrosive to lithium anodes. Batteries constructed with this improved electrolyte utilize lithium or lithium alloy anodes and cathodes made of metal chalcogenides or oxides, such as TiS.sub.2, NbSe.sub.3, V.sub.6 O.sub.13, V.sub.2 O.sub.5, MoS.sub.2, MoS.sub.3, CoO.sub.2, or CrO.sub.2, dissolved in a supporting polymer matrix, like EPDM. The preferred non-aqueous solvent mixture comprises approximately 5 to 30 volume percent ethylene carbonate, approximately 0.01 to 0.1 weight percent ethylene propylene diene terpolymer, and approximately 0.2 to 2 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The most preferred solvent comprises approximately 10 to 20 volume percent ethylene carbonate, about 0.05 weight percent ethylene propylene diene terpolymer, and about 1.0 percent 2-methylfuran, with the balance being 2-methyltetrahydrofuran. The concentration of lithium arsenic hexafluoride can range from about 1.0 to 1.8 M; a concentration 1.5 M is most preferred. Secondary batteries made with the improved electrolyte of this invention have lower internal impedance, longer cycle life, higher energy density, low self-discharge, and longer shelf life.

Shen, David H.↗
NASA NTRS1985

Corrosion of metals by hydrazine

The mechanism of corrosion of metals by hydrazine has been studied by means of coupons in sealed ampoules and by electrochemical techniques. The variables considered were temperature, CO2 impurity level, alloy composition and microcrystalline structure. The coupon studies, to date, verify that increasng temperature and the presence of CO2 does increase the corrosion rate as expected. The presence of molybdenum in stainless steels to the 3 percent level is not necessarily deleterious, contrary to published reports. The influence of microcrystalline structure and surface characteristics are more dominant effects. However, with Ti-6Al-4V, two different microcrystalline structures showed no significant differences. Corrosion rates of CRES 304 L in hydrazine have also been measured by several electrochemical techniques such as Tafel plots, polarization resistance and A. C. Impedance. This is the first documented work to show that A. C. Impedance can be used with non-aqueous solvents. Preliminary data correlated satisfactorily with the results of the coupon studies.

Lawton, E. A.↗
NASA NTRS1989

Physical phenomena and the microgravity response

The living biological cell is not a sack of Newtonian fluid containing systems of chemical reactions at equilibrium. It is a kinetically driven system, not a thermodynamically driven system. While the cell as a whole might be considered isothermal, at the scale of individual macromolecular events there is heat generated, and presumably sharp thermal gradients exist at the submicron level. Basic physical phenomena to be considered when exploring the cell's response to inertial acceleration include particle sedimentation, solutal convection, motility electrokinetics, cytoskeletal work, and hydrostatic pressure. Protein crystal growth experiments, for example, illustrate the profound effects of convection currents on macromolecular assembly. Reaction kinetics in the cell vary all the way from diffusion-limited to life-time limited. Transport processes vary from free diffusion, to facilitated and active transmembrane transport, to contractile-protein-driven motility, to crystalline immobilization. At least four physical states of matter exist in the cell: aqueous, non-aqueous, immiscible-aqueous, and solid. Levels of order vary from crystalline to free solution. The relative volumes of these states profoundly influence the cell's response to inertial acceleration. Such subcellular phenomena as stretch-receptor activation, microtubule re-assembly, synaptic junction formation, chemotactic receptor activation, and statolith sedimentation were studied recently with respect to both their basic mechanisms and their responsiveness to inertial acceleration. From such studies a widespread role of cytoskeletal organization is becoming apparent.

Todd, Paul↗
NASA NTRS1998

Microcapsules and Methods for Making

Methods of forming multi-lamellar microcapsules having alternating layers of hydrophilic and hydrophobic immiscible liquid phases have been developed using different polymer/solvent systems. The methods use liquid-liquid diffusion and simultaneous lateral phase separation, controlled by proper timed-sequence exposures of immiscible phases and low shear mixing, to form narrow size distributions of spherical, multilamellar microcapsules. The use of special formulations of solubilized drugs, surfactants, and polymeric co-surfactants in aqueous vehicles which are dispersed in hydrocarbon solvents containing small quantities of oil, low molecular weight co-surfactants and glycerides that are aqueous insoluble enables the formation of unique microcapsules which can carry large amounts of pharmaceuticals in both aqueous and non-aqueous solvent compartments. The liquid microcapsules are quickly formed in a single step and can include a polymeric outer 'skin' which protects the microcapsules during physical manipulation or exposure to high shear forces. Water-in-oil and oil-in-water microcapsules have been formed both in 1 x g and in microgravity, which contain several types of drugs co-encapsulated within different fluid compartments inside the same microcapsule. Large, spherical multi-lamellar microcapsules have been formed including a cytotoxic drug co-encapsulated with a radiocontrast medium which has advantages for chemoembolization of vascular tumors. In certain cases, crystals of the drug form inside the microcapsules providing zero-order and first order, sustained drug release kinetics.

Morrison, Dennis R.↗
NASA NTRS2001

An Overview of In-Stu Treatability Studies at Marshall Space Flight Center, Huntsville, Alabama

Marshall Space Flight Center (MSFC) is located in Huntsville, Alabama (north-central Alabama), on approximately 1,840 acres near the center of the U.S. Army's Redstone Arsenal (RSA). MSFC is the National Aeronautics and Space Administration's (NASA's) principal propulsion development center. Its scientists, engineers, and support personnel play a major role in the National Space Transportation System by managing space shuttle mission activities, including the microgravity laboratory. In addition, MSFC will be a significant contributor to several of NASA's future programs, including the Reusable Launch Vehicle (X-33), International Space Station, and Advanced X-ray Astrophysics Facility, as well as research on a variety of space science applications. MSFC has been used to develop, test and manufacture space vehicles and components since 1960, when civilian rocketry and missile activities were transferred from RSA to MSFC. In 1994, MSFC was placed on the National Priority List for the management of hazardous waste sites, under the requirements of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). One requirement of the CERCLA program is to evaluate the nature and extent of environmental contamination resulting from identified CERCLA sites, assess the public health and environmental risks associated with the identified contamination, and identify potential remedial actions. A CERCLA remedial investigation (RI) for the groundwater system has identified at least five major plumes of chlorinated volatile organic compounds (CVOCs) in the groundwater beneath the facility. These plumes are believed to be the result of former management practices at 14 main facility locations (termed "source areas") where CVOCs were released to the subsurface. Trichloroethene (TCE) is the predominant CVOC and is common to all the plumes. Perchloroethene (PCE) also exists in two of the plumes. In addition to TCE and PCE, carbon tetrachloride and 1,1,2,2-tetrachloroethane are contained in one of the plumes. The CVOCs are believed to exist as dense non-aqueous phase liquids (DNAPLs) beneath many of the source areas.

McElroy, Bill↗
NASA NTRS2002

Infrared Spectroscopy as a Chemical Fingerprinting Tool

Infrared (IR) spectroscopy is a powerful analytical tool in the chemical fingerprinting of materials. The technique is rapid, reproducible and usually non-invasive. With the appropriate accessories, the technique can be used to examine samples in either a solid, liquid or gas phase. Solid samples of varying sizes and shapes may be used, and with the addition of microscopic IR (microspectroscopy) capabilities, minute materials such as single fibers and threads may be examined. With the addition of appropriate software, microspectroscopy can be used for automated discrete point or compositional surface area mapping, with the latter providing a means to record changes in the chemical composition of a material surface over a defined area. Both aqueous and non-aqueous free-flowing solutions can be analyzed using appropriate IR techniques, as can viscous liquids such as heavy oils and greases. Due to the ability to characterize gaseous samples, IR spectroscopy can also be coupled with thermal processes such as thermogravimetric (TG) analyses to provide both thermal and chemical data in a single run. In this configuration, solids (or liquids) heated in a TG analyzer undergo decomposition, with the evolving gases directed into the IR spectrometer. Thus, information is provided on the thermal properties of a material and the order in which its chemical constituents are broken down during incremental heating. Specific examples of these varied applications will be cited, with data interpretation and method limitations further discussed.

Huff, Tim↗
NASA NTRS2002

Nanoscale and Microscale Iron Emulsions for Treating DNAPL

This study demonstrated the feasibility of using emulsified nanoscale and microscale iron particles to enhance dehalogenation of (Dense Non-Aqueous Phase Liquid) DNAPL free-phase. The emulsified system consisted of a surfactant-stabilized, biodegradable oil-in-water emulsion with nanoscale or microscale iron particles contained within the emulsion droplets. It was demonstrated that DNAPLs, such as trichloroethene (TCE), diffuse through the oil membrane of the emulsion particle whereupon they reach an aqueous interior and the surface of an iron particle where dehalogenation takes place. The hydrocarbon reaction by-products of the dehalogenation reaction, primarily ethene (no chlorinated products detected), diffuse out of the emulsion droplet. This study also demonstrated that an iron-emulsion system could be delivered in-situ to the DNAPL pool in a soil matrix by using a simulated push well technique. Iron emulsions degraded pure TCE at a rate comparable to the degradation of dissolved phase TCE by iron particles, while pure iron had a very low degradation rate for free-phase TCE. The iron-emulsion systems can be injected into a sand matrix where they become immobilized and are not moved by flowing water. It has been documented that surfactant micelles possess the ability to pull pooled TCE into emulsion droplets where degradation of TCE takes place.

Geiger, Cherie L.↗
NASA NTRS2003

Zero-Valent Metal Emulsion for Reductive Dehalogenation of DNAPLS

A zero-valent metal emulsion is used to dehalogenate solvents, such as pooled dense non-aqueous phase liquids (DNAPLs), including trichloroethylene (TCE). The zero-valent metal emulsion contains zero-valent metal particles, a surfactant, oil and water. The preferred zero-valent metal particles are nanoscale and microscale zero-valent iron particles

Debra R Reinhart↗