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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

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NASA NTRS1990

Availability of hydrogen for lunar base activities

Hydrogen will be needed on a lunar base to make water for consumables, to provide fuel, and to serve as reducing agent in the extraction of oxygen from lunar minerals. The abundance and distribution of solar wind implanted hydrogen were studied. Hydrogen was found in all samples studied with concentrations varying widely depending on soil maturity, grain size, and mineral composition. Seven cores returned from the moon were studied. Although hydrogen was implanted in the upper surface layer of the regolith, it was found throughout the cores due to micrometeorite reworking of the soil.

Bustin, Roberta↗

NASA NTRS1990

Kinetics of hydrogen release from lunar soil

With increasing interest in a lunar base, there is a need for extensive examination of possible lunar resources. Hydrogen will be needed on a lunar base for many activities including providing fuel, making water, and serving as a reducing agent in the extraction of oxygen from its ores. Previous studies have shown the solar wind has implanted hydrogen in the lunar regolith and that hydrogen is present not only in the outer layer of soil but to considerable depths, depending on the sampling site. If this hydrogen is to be mined and used on the lunar surface, a number of questions need to be answered. How much energy must be expended in order to release the hydrogen from the soil. What temperatures must be attained, and how long must the soil be heated. This study was undertaken to provide answers to practical questions such as these. Hydrogen was determined using a Pyrolysis/GC technique in which hydrogen was released by heating the soil sample contained in a quartz tube in a resistance wire furnace, followed by separation and quantitative determination using a gas chromatograph with a helium ionization detector. Heating times and temperatures were varied, and particle separates were studied in addition to bulk soils. The typical sample size was 10 mg of lunar soil. All of the soils used were mature soils with similar hydrogen abundances. Pre-treatments with air and steam were used in an effort to find a more efficient way of releasing hydrogen.

Bustin, Roberta↗

NASA NTRS1991

Chemical approaches to carbon dioxide utilization for manned Mars missions

Use of resources available in situ is a critical enabling technology for a permanent human presence in space. A permanent presence on Mars, e.g., requires a large infrastructure to sustain life under hostile conditions. As a resource on Mars, atmospheric CO2 is as follows: abundant; available at all points on the surface; of known presence; chemically simple; and can be obtained by simple compression. Many studies focus on obtaining O2 and the various uses for O2 including life support and fuel; discussion of CO, the coproduct from CO2 fixation revolves around its uses as a fuel, being oxidized back to CO2. Several new proposals are studied for CO2 fixation through chemical, photochemical, and photoelectrochemical means. For example, the reduction of CO2 to hydrocarbons such as acetylene (C2H2) can be accomplished with H2. C2H2 has a theoretical vacuum specific impulse of approx. 375 secs. Potential uses were also studied of CO2, as obtained or further reduced to carbon, as a reducing agent in metal oxide processing to form metals or metal carbides for use as structural or power materials; the CO2 can be recycled to generate O2 and CO.

Hepp, Aloysius F.↗

NASA NTRS1989

Production of oxygen from lunar ilmenite

The overall objective of this project was to develop a novel carbothermal reduction process for production of oxygen from lunar ilmenite. The specific objective was to use a reaction sequence in which a wide variety of carbonaceous compounds (including carbonaceous wastes) can be used as reducing agents. During the first phase, two reactor systems were designed, constructed, and operated to study the reaction fundamental important in this process. One system is a small fluidized bed, and the other is a thermo-gravimetric reactor system. Preliminary experiments on synthetic ilmenite are conducted to study the effect of carbon type, carbon loading, temperature, and gas flow rate. Results indicate that a reaction path based on carbon gasification can be used to promote the overall kinetics. A unique temperature and concentration-programmed reaction procedure was being developed for rapid parametric study of the process.

Shadman, F.↗

NASA NTRS1992

Occupational safety considerations with hydrazine

Hydrazine is a reducing agent that is most commonly used as a propellant and as an oxygen scavenger in boilers. Hydrazine is extremely irritating and has been demonstrated to produce both acute and chronic toxicity. As a result, the established permissible inhalation exposure limits are very low, and respiration protection is required whenever vapors are present. Liquid hydrazine penetrates the skin and produces a chemical burn; therefore, some protective measures must also be taken to protect the skin from liquid contact. Often, however, a cumbersome, whole-body protective suit is worn to protect against skin contact with vapor as well. To what extent it is actually necessary to protect skin from vapor penetration had not previously been demonstrated. In an attempt to answer this question, we conducted a study with rats to compare the dermal penetration of hydrazine vapor with inhalation. Pharmacokinetic modeling was used to compare body burdens resulting from these different routes of exposure. The analysis concluded that the vapor concentration during a skin-only exposure would have to be at least 200 times higher than that during inhalation to achieve the same body burden. This type of estimation illustrates the use of predictive toxicology in occupational exposures.

Clewell, Harvey J., III↗

NASA NTRS1991

In-situ carbon dioxide fixation on Mars

The authors examine several novel proposals for CO2 fixation through chemical, photochemical, and photoelectrochemical means. For example, the reduction of CO2 to hydrocarbons such as acetylene (C2H2) can be accomplished with hydrogen. Acetylene has a theoretical vacuum specific impulse of about 375 s. The authors also examine potential uses of CO, as obtained or further reduced to carbon, as a reducing agent in metal oxide processing to form metals or metal carbides for use as structural or power materials. The CO2 can be recycled to generate O2 and CO. In this study, the authors examine reaction schemes for processing in situ resources. The authors highlight chemistry with hydrogen and carbon monoxide to produce propellants and other necessities of manned exploration.

Hepp, Aloysius F.↗

NASA NTRS1992

Availability of hydrogen for lunar base activities

Hydrogen will be needed on a lunar base to make water for consumables, to provide fuel, and to serve as a reducing agent in the extraction of oxygen from lunar minerals. This study was undertaken in order to learn more about the abundance and distribution of solar-wind-implanted hydrogen. Hydrogen was found in all samples studied, with concentrations, varying widely depending on soil maturity, grain size, and mineral composition. Seven cores returned from the Moon were studied. Although hydrogen was implanted in the upper surface layer of the regolith, it was found throughout the cores due to micrometeorite reworking of the soil.

Bustin, Roberta↗

NASA NTRS1994

Analysis for nickel (3 and 4) in positive plates from nickel-cadmium cells

The NASA-Goddard procedure for destructive physical analysis (DPA) of nickel-cadmium cells contains a method for analysis of residual charged nickel as NiOOH in the positive plates at complete cell discharge, also known as nickel precharge. In the method, the Ni(III) is treated with an excess of an Fe(II) reducing agent and then back titrated with permanganate. The Ni(III) content is the difference between Fe(II) equivalents and permanganate equivalents. Problems have arisen in analysis at NAVSURFWARCENDIV, Crane because for many types of cells, particularly AA-size and some 'space-qualified' cells, zero or negative Ni(III) contents are recorded for which the manufacturer claims 3-5 percent precharge. Our approach to this problem was to reexamine the procedure for the source of error, and correct it or develop an alternative method.

Lewis, Harlan L.↗

NASA NTRS1995

The synthesis of glutamic acid in the absence of enzymes: Implications for biogenesis

This paper reports on the non-enzymatic aqueous phase synthesis of amino acids from keto acids, ammonia and reducing agents. The facile synthesis of key metabolic intermediates, particularly in the glycolytic pathway, the citric acid cycle, and the first step of amino acid synthesis, lead to new ways of looking at the problem of biogenesis.

Morowitz, Harold↗

NASA NTRS1998

Peculiarities of Crystallization of the Restriction Endonuclease EcoRII

Nucleases interfere with most standard molecular biology procedures. We have purified and crystallized the restriction endonuclease EcoRII, which belongs to the type II of restriction- modification enzyme, to study the protein crystallization process using a "non standard" macromolecule. A procedure for the purification of EcoRII was developed and 99% pure protein as determined by SDS PAGE electrophoresis obtained. Light scattering experiments were performed to assist in screening protein suitable crystallization conditions. The second virial coefficient was determined as a function of precipitating salt concentration, using sodium chloride, ammonium sulfate, and sodium sulfate. Small (maximum size approximately 0.2 mm) well shaped crystals have been obtained. Larger poorly formed crystals (ca 0.5 mm) have also been obtained, but we have been unable to mount them for diff-raction analysis due to their extreme fragility. Crystallization experiments with PEG have shown that using this precipitant, the best crystals are obtained from slightly over-saturated solutions. Use of higher precipitant concentration leads to dendritic crystal formation. EcoRII is difficult to solubilize and meticulous attention must be paid to the presence of reducing agents.

Karpove, Elizaveta↗

NASA NTRS1999

High-Resolution Mapping of Lunar Crustal Magnetic Fields: Correlations with Albedo Markings of the Reiner Gamma Class

During the last eight months of the Lunar Prospector mission (December 1999-July 1999), the spacecraft was placed in a relatively low-altitude (15-30-km perapsis), near-polar orbit that allowed high-resolution mapping of crustal magnetic fields. We report here initial studies of the correlation of locally strong magnetic anomalies with unusual, swirl-like albedo markings of the Reiner Gamma class. Based on this correlation, which is known from earlier studies of Apollo subsatellite magnetometer data, it has been proposed that the swirls represent regions whose higher albedos have been preserved via deflection of the solar-wind ion bombardment by strong crustal fields. This model in turn depends on the hypothesis that solar-wind implanted H is at least one component of the process that optically matures exposed silicate surfaces in the inner solar system . Specifically, it is hypothesized that implanted H acts as an effective reducing agent to enhance the rate of production of nanophase metallic Fe particles from preexisting silicates during micrometeoroid impacts. According to the model, the curvilinear shapes of these albedo markings are caused, at least in part, by the geometry of ion deflections in a magnetic field. The improved resolution and coverage of the Prospector data allow more detailed mapping of the fields, especially on the lunar farside. This permits a more quantitative test of whether all albedo markings of this class are associated with strong local magnetic fields.Only if the latter condition is met can the solar-wind deflection hypothesis he valid. The basic procedure for mapping crustal magnetic fields using Lunar Prospector magnetometer data follows that developed for analysis of Apollo subsatellite magnetometer data. The specific mapping steps are (1) selection of mission time intervals suitable for mapping crustal fields; these are limited essentially either to times when the Moon is in a lobe of the geomagnetic tail or to times when the Moon is in the solar wind but the spacecraft is in the lunar wake; the data are transformed to a radial, east, and north coordinate system with measurements given as a function of spacecraft latitude, longitude, and altitude; (2) visual editing of individual orbit segments selected for minimal external field disturbances; (3) minimization of remaining low-frequency external fields for individual orbit data segments by quadratic detrending; and (4) two-dimensional filtering of individual orbit segments to produce a vector field map along the slightly curved surface defined by the spacecraft altitude; maps of the three field components (radial, east, and north), the field magnitude, and the spacecraft altitude are constructed. For data obtained at low to middle latitudes, the horizontal resolution of the field maps is limited by the orbit-track separation (about 30 km at the equator). Maps of the field magnitude have been constructed within limited selenographic regions based mainly on data acquired in March, April, and May of 1999. This was a time period when the orbit plane was nearly aligned with the Sun-Moon line so that field mapping was possible at times when the Moon was in the solar wind as well as when the Moon was in the geomagnetic tail. Most of the coverage is across the lunar farside. However, a shows an example of a field map produced from solar-wind wake data for a region including Reiner Gamm on western Oceanus Procellarum (location: 58.5W, 7.5N). The contour interval is 3 nT and the mean spacecraft altitude is 18 km to within the accuracy allowed by the resolution of the map (30 km or about 1 deg.); strong magnetic anomalies correlate closely with swirl locations. Individual orbit profiles (whose resolution along the orbit track is comparable to the spacecraft altitude of 18 km) also demonstrate a good correlation of field magnitude with surface albedo. In order to investigate the correlation of magnetic fields with the location of swirl features, we have reexamined available lunar imagery (Lunar Orbiter, Apollo, and Clementine) to identify and map swirl locations within regions where swirls have previously been mapped. In these images, swirls were distinguished from other high-albedo features such as crater rays by their curvilinear shapes and increased visibility in forward-scattered light. Digital maps of swirls identified by all available imagery were then superposed on maps of the field magnitude at the spacecraft altitude. Based upon analysis of these composite magnetic/geologic maps, we draw the preliminary conclusion that swirl features are associated with magnetic anomalies revealed by Lunar Prospector. Detailed maps of these swirl features are currently being constructed for the magnetically strong regions antipodal to the Imbrium, Serenitatis, and Crisium Basins. Additional information contained in the original,

Hood, L. L.↗

NASA NTRS2000

Maghemite Formation via Organics and the Prospect for Maghemite as a Biomarker Mineral on Mars

One of the major questions on Mars is the origin of the magnetic component in the surface material. Our work on maghemite formation suggests that alteration of femhydrite in the presence of organics would provide a plausible formation scenario for this magnetic soil component and further suggests that maghemite might be an important biomarker mineral on Mars. Identification of biomarker minerals is an important aspect of Astrobiology . The iron oxide mineral maghemite is thought to be one of the magnetic components in the Martian surface material; however, it is a rare mineral on the Earth and requires a reducing agent for synthesis. Organic material serves as a reductant in maghemite formation during forest fires on Earth and may play an important role in maghemite formation on Mars through low-temperature heating (e.g., volcanism, impacts). This study involves analysis of magnetite, maghemite and hematite formation under Martian environmental conditions from femhydrite in the presence and absence of organics. A dehydrated version of the mineral femhydrite is thought to be present in Martian soil/dust grains and could have formed at an earlier time on Mars when water was present. Our work indicates that low-temperature alteration of femhydrite in the presence of organic material could be an important mechanism on Mars.

Bishop, Janice↗

NASA NTRS1991

Air oxidation of hydrazine. 1. Reaction kinetics on natural kaolinites, halloysites, and model substituent layers with varying iron and titanium oxide and O- center contents

Air oxidation of hydrazine was studied by using a group of kaolinites, halloysites, and substituent oxides as models for the tetrahedral and octahedral sheets. The rate was found to be linear with oxygen. The stoichiometry showed that oxygen was the primary oxidant and that dinitrogen was the only important nitrogen-containing product. The rates on kaolinites were strongly inhibited by water. Those on three-dimensional silica and gibbsite appeared not to be. That on a supposedly layered silica formed from a natural kaolinite by acid leaching showed transitional behavior--slowed relative to that expected from a second-order reaction relative to that on the gibbsite and silica but faster than those on the kaolinites. The most striking result of the reaction was the marked increase in the rate of reaction of a constant amount of hydrazine as the amount of clay was increased. The increase was apparent (in spite of the water inhibition at high conversions) over a 2 order of magnitude variation of the clay weight. The weight dependence was taken to indicate that the role of the clay is very important, that the number of reactive centers is very small, or that they may be deactivated over the course of the reaction. In contrast to the strong dependence on overall amount of clay, the variation of amounts of putative oxidizing centers, such as structural Fe(III), admixed TiO2 or Fe2O3, or O- centers, did not result in alteration of the rate commensurate with the degree of variation of the entity in question. Surface iron does play some role, however, as samples that were pretreated with a reducing agent were less active as catalysts than the parent material. These results were taken to indicate either that the various centers interact to such a degree that they cannot be considered independently or that the reaction might proceed by way of surface complexation, rather than single electron transfers.

NASA Discipline Number 52-20↗

NASA NTRS1992

Two endogenous proteins that induce cell wall extension in plants

Plant cell enlargement is regulated by wall relaxation and yielding, which is thought to be catalyzed by elusive "wall-loosening" enzymes. By employing a reconstitution approach, we found that a crude protein extract from the cell walls of growing cucumber seedlings possessed the ability to induce the extension of isolated cell walls. This activity was restricted to the growing region of the stem and could induce the extension of isolated cell walls from various dicot stems and the leaves of amaryllidaceous monocots, but was less effective on grass coleoptile walls. Endogenous and reconstituted wall extension activities showed similar sensitivities to pH, metal ions, thiol reducing agents, proteases, and boiling in methanol or water. Sequential HPLC fractionation of the active wall extract revealed two proteins with molecular masses of 29 and 30 kD associated with the activity. Each protein, by itself, could induce wall extension without detectable hydrolytic breakdown of the wall. These proteins appear to mediate "acid growth" responses of isolated walls and may catalyze plant cell wall extension by a novel biochemical mechanism.

Non-NASA Center↗

NASA NTRS1994

Purification of recombinant budgerigar fledgling disease virus VP1 capsid protein and its ability for in vitro capsid assembly

A recombinant system for the major capsid VP1 protein of budgerigar fledgling disease virus has been established. The VP1 gene was inserted into a truncated form of the pFlag-1 vector and expressed in Escherichia coli. The budgerigar fledgling disease virus VP1 protein was purified to near homogeneity by immunoaffinity chromatography. Fractions containing highly purified VP1 were pooled and found to constitute 3.3% of the original E. coli-expressed VP1 protein. Electron microscopy revealed that the VP1 protein was isolated as pentameric capsomeres. Electron microscopy also revealed that capsid-like particles were formed in vitro from purified VP1 capsomeres with the addition of Ca2+ ions and the removal of chelating and reducing agents.

NASA Discipline Developmental Biology↗

NASA NTRS2004

Developing Glassy Magnets from Simulated Composition of Martian Soil for Exploration Applications

The long-term exploration goals of NASA include developing human habitation on Mars and conducting scientific investigations on Mars and other planetary bodies. In situ resource processing is a key objective in this area We focus OR the possibility of making magnetic glasses in situ for potential applications development. The paper will focus on ongoing work at NASA Marshall Space Flight Center on making magnetic glass h m Mars soil simulants and its characterization. Analysis of the glass morphology, strength, chemistry and resulting magnetic properties will provide a fi.mdamenta1 understanding ofthe synthesized materiai that can be used for pomtiai appiications cieveiopment. In an effort to characterize the magnetic properbes of the Mars glasses, a series of tests were performed at NASA MSFC. Preliminary tests indicated that the glasses were attracted to a magnet and also had a small amount of residual magnetism. They were opaque (almost black in color). As the first step, a sample of Mars 1 glass (-lm x lmm x 5 mm length) was machined, weighed and its hysteresis curve was measured using a Vibration Sample Magnetometer 0. Next, a small furnace was designed and built and the sample was baked in a graphite (reducing agent) crucible at 800 C in an Argon atmosphere for 3 hours in the presence of a uniform, transverse (transverse to the 5mm length of the sample) magnetic field of 0.37 Tesla. The treated sample showed reddening on the outside and showed substantially increased residual magnetism. This sample was again analyzed in the VSM. The data clearly showed that some chemical change occurred during the heat treatment (color change) and that both the glasses have useful magnetic properties. Although no orientation effects of the magnetic field were considered, the data showed the following: 1. Both glass samples are primarily soft magnets and display ferromagnetic behavior (hysteresis, saturation, etc.) 2. The treated glass has improved saturation magnetism (order of magnitude increase), retentivity (factor of 6 increase) and susceptibility (order of magnitude increase) compared to the untreated glass 3. The untreated sample has higher coercivity (-50% that of Nickel) than the treated sample

Ramachandran, Narayanan↗

NASA NTRS2004

Developing Glassy Magnets from Simulated Composition of Martian Soil for Exploration Applications

The long-term exploration goals of NASA include developing human habitation on Mars and conducting scientific investigations on Mars and other planetary bodies. In situ resource processing is a key objective in this area. We focus on the possibility of making magnetic glasses in situ for potential applications development. The paper will focus on ongoing work at NASA Marshall Space Flight Center on making magnetic glass from Mars soil simulants and its characterization. Analysis of the glass morphology, strength, chemistry and resulting magnetic properties will provide a fundamental understanding of the synthesized material that can be used for potential applications development. in an effort to characterize the magnetic properties of the Mars glasses, a series of tests were performed at NASA MSFC. Preliminary tests indicated that the glasses were attracted to a magnet and also had a small amount of residual magnetism. They were opaque (almost black in color). As the first step, a sample of Mars 1 glass (approx.1 mm x 1 mm x 5 mm length) was machined, weighed and its hysteresis curve was measured using a Vibration Sample Magnetometer (VSM). Next, a small furnace was designed and built and the sample was baked in a graphite (reducing agent) crucible at 800 C in an Argon atmosphere for 3 hours in the presence of a uniform, transverse (transverse to the 5mm length of the sample) magnetic field of 0.37 Tesla. The treated sample showed reddening on the outside and showed substantially increased residual magnetism. This sample was again analyzed in the VSM. The data clearly showed that some chemical change occurred during the heat treatment (color change) and that both the glasses have useful magnetic properties. Although no orientation effects of the magnetic field were considered, the data showed the following: 1. Both glass samples are primarily soft magnets and display ferromagnetic behavior (hysteresis, saturation, etc.) 2. The treated glass has improved saturation magnetism (order of magnitude increase), retentivity (factor of 6 increase) and susceptibility (order of magnitude increase) compared to the untreated glass 3. The untreated sample has higher coercivity (approx.50% that of Nickel) than the treated sample 4. Both samples have similar energy density. Results from a systematic study to quantify the effects of processing conditions such as heat treatment, atmosphere, containerless processing (by electrostatic levitation), and applications of external magnetic fields of different strengths will be discussed. Efforts on optimizing the magnetic properties of the product and the feasibility of using it for a couple of specific magnetic applications such as heat generation using an ac field and for electro forming will also be covered. The latter is an in situ manufacturing technique being studied for in-space fabrication applications at MSFC.

Ramachandran, N.↗

NASA NTRS2007

Methods for synthesis of semiconductor nanocrystals and thermoelectric compositions

The present invention provides methods for synthesis of IV VI nanostructures, and thermoelectric compositions formed of such structures. In one aspect, the method includes forming a solution of a Group IV reagent, a Group VI reagent and a surfactant. A reducing agent can be added to the solution, and the resultant solution can be maintained at an elevated temperature, e.g., in a range of about 20.degree. C. to about 360.degree. C., for a duration sufficient for generating nanoparticles as binary alloys of the IV VI elements.

Ren, Zhifeng↗