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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 NTRS2015

On Infrared Excesses Associated with Li-Rich K Giants

Infrared (IR) excesses around K-type red giants (RGs) have previously been discovered using Infrared Astronomy Satellite (IRAS) data, and past studies have suggested a link between RGs with overabundant lithium and IR excesses, implying the ejection of circumstellar shells or disks. We revisit the question of IR excesses around RGs using higher spatial resolution IR data, primarily from the Wide-field Infrared Survey Explorer. Our goal was to elucidate the link between three unusual RG properties: fast rotation, enriched lithium, and IR excess. Our sample of RGs includes those with previous IR detections, a sample with well-defined rotation and lithium abundance measurements with no previous IR measurements, and a large sample of RGs asserted to be lithium-rich in the literature; we have 316 targets thought to be K giants, about 40% of which we take to be Li-rich. In 24 cases with previous detections of IR excess at low spatial resolution, we believe that source confusion is playing a role, in that either (a) the source that is bright in the optical is not responsible for the IR flux, or (b) there is more than one source responsible for the IR flux as measured in IRAS. We looked for IR excesses in the remaining sources, identifying 28 that have significant IR excesses by approximately 20 micrometers (with possible excesses for 2 additional sources). There appears to be an intriguing correlation in that the largest IR excesses are all in Li-rich K giants, though very few lithium-rich K giants have IR excesses (large or small). These largest IR excesses also tend to be found in the fastest rotators. There is no correlation of IR excess with the carbon isotopic ratio, 12C/13C. IR excesses by 20 micrometers, though relatively rare, are at least twice as common among our sample of lithium-rich K giants. If dust shell production is a common by-product of Li enrichment mechanisms, these observations suggest that the IR excess stage is very short-lived, which is supported by theoretical calculations. Conversely, the lithium-enrichment mechanism may only occasionally produce dust, and an additional parameter (e.g., rotation) may control whether or not a shell is ejected.

Li-rich↗
NASA NTRS1980

Glass shell manufacturing in space

A heat transfer model was developed that mathematically describes the heating and calculates the thermal history of a gel particle in free-fall through the furnace. The model parameters that greatly affect the calculations were found to be gel particle mass, geometry, specific heat, and furnace gas. Empirical testing of the model has commenced. The code calculations and the initial empirical testing results both indicate that the gel-to-shell transformation occurs early and rapidly in the thermal history of the gel particle, and that for current work the heat transfer rate is not a limitation in shell production.

Nolen, R. L., Jr.↗
NASA NTRS1986

Implementation of a data management software system for SSME test history data

The implementation of a software system for managing Space Shuttle Main Engine (SSME) test/flight historical data is presented. The software system uses the database management system RIM7 for primary data storage and routine data management, but includes several FORTRAN programs, described here, which provide customized access to the RIM7 database. The consolidation, modification, and transfer of data from the database THIST, to the RIM7 database THISRM is discussed. The RIM7 utility modules for generating some standard reports from THISRM and performing some routine updating and maintenance are briefly described. The FORTRAN accessing programs described include programs for initial loading of large data sets into the database, capturing data from files for database inclusion, and producing specialized statistical reports which cannot be provided by the RIM7 report generator utility. An expert system tutorial, constructed using the expert system shell product INSIGHT2, is described. Finally, a potential expert system, which would analyze data in the database, is outlined. This system could use INSIGHT2 as well and would take advantage of RIM7's compatibility with the microcomputer database system RBase 5000.

Abernethy, Kenneth↗
NASA NTRS1982

Hydrodynamic performance of an annular liquid jet: Production of spherical shells

An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Axisymmetric oscillations arise spontaneously, and grow with such rapidity along the axial dimension that a pinch-off of the liquid and an encapsulation of the core gas occurs within as few as four jet diameters. The shells which result thereby may be described as thick-wall bubbles, for which van der Waals forces are unimportant. A description is given of the fluid dynamic processes by which the shells are formed, and of means for preserving and promoting the geometrical of the product. The forming of metallic shells is mentioned.

Kendall, J. M.↗
NASA NTRS1988

Electromagnetic-capillary instabilities of a hollow liquid cylinder - Production of spherical shells under microgravity conditions

An electrical device is proposed for manufacturing spherical shells out of hollow metallic cylinders in a microgravity environment. Such a cylinder is melted by passing a strong axial current through it. The resulting liquid column is unstable to axisymmetric disturbances and breaks up to form hollow spheres after solidification. The stability analysis presented in this paper, which is based on an inviscid magnetohydrodynamic formulation, shows that the size of the spheres may be controlled by varying the strength of the current passed through the column.

Chow, C.-Y.↗
NASA NTRS1982

Metal shell technology based upon hollow jet instability

Spherical shells of submillimeter size are sought as ICF targets. Such shells must be dimensionally precise, smooth, of high strength, and composed of a high atomic number material. A technology for the production of shells based upon the hydrodynamic instability of an annular jet of molten metal is described. Shells in the 0.7-2.0 mm size range have been produced using tin as a test material. Specimens exhibit good sphericity, fair concentricity, and excellent finish over most of the surface. Work involving a gold-lead-antimony alloy is in progress. Droplets of this are amorphous and possess superior surface finish. The flow of tin models that of the alloy well; experiments on both metals show that the technique holds considerable promise.

Kendall, J. M.↗
NASA NTRS1977

Production of soft X-ray emitting slow multiply charged ions - Recoil ion spectroscopy

S ions with a mean charge state of about 14+ and Cl ions with a mean charge state of 12+ were used to study Ne L-shell vacancy production. The ions caused copious production of NeII-NeVIII excited states with approximately 10 to the minus 18 sq cm cross sections. The induced recoil velocities might have application to a significantly higher resolution spectroscopy than is possible with beam-foil methods.

Sellin, I. A.↗
NASA NTRS2004

Formation and Stability of Radiation Products in Europa's Icy Shell

Spectra of Europa reveal a surface dominated by water-ice along with hydrated materials and minor amounts of SO2, CO2, and H2O2. Jovian magnetospheric ions (protons, sulfur, and oxygen) and electrons produce significant chemical modifications of the surface on time scales of a few years at micrometer depths. Our laboratory studies examine the formation and stability of radiation products in H2O-rich ices relevant to Europa. Infrared (IR) spectra of ices before and after irradiation reveal the radiation destruction of molecules and the formation of products at 86 - 132 K. In addition, spectra of ices during warming track thermal evolution due to chemical changes and sublimation processes. IR-identified radiation products in 86 - 132 K irradiated H2O + SO2 ices are the bisulfate ion, HSO4(-), sulfate ion, SO4(2-) and the hydronium ion, H3O(+). Warming results in the formation of a residual spectrum similar to liquid sulfuric acid, H2SO4, for H2O:SO2 ratios of 30:1, whereas hydrated sulfuric acid, H2SO4 4 H2O, forms for ratios of 30:1. Radiation products identified for irradiated H2O + H2S ices at 86 K are H2S2 and SO2. When irradiated at 110 and 132 K, ices with H2O:H2S ratios if either 3:1 or 30:1 show the formation of H2SO4 4 H2O on warming to 175 K. We have also examined the radiation stability of H2SO4. Addition of CO2 to H2O + SO2 ices results in the formation of CO3 at 2046 cm (sup -1) (4.89 m). This is the strongest band from a carbon-containing product in the mid-IR spectral region, and it is also seen when either pure CO2 or H2O + CO2 ice is irradiated. Experiments with CH4 added to H2O + SO2 + CO2 ices addressed the question of methane's use as a marker of methanogens in an irradiated ice environment. New results on the near-IR spectrum of pure H2O2 will be included in this presentation. Interpretations of near-IR water bands, with H2O2 present, will be discussed. Irradiations of H2O2 and H2O + H2O2 mixtures, to examine the possibility of O2 and O3 formation, are currently under investigation and new results will be discussed.

Moore, M. H.↗
NASA NTRS1991

The spin state and homogeneity of Comet Halley's nucleus

The present model of the spin rate of Comet Halley, which takes the form of an excited, axially symmetric rotator with prolate spheroid shape, accommodates both the imaging data from the Vega and Giotto encounters and a range of ground-based data for CN jets and shells, C2 production rates, and photometric variability. The model ratio of moments-of-inertia maxima to minima, at 2.28, implies a nearly constant density distribution throughout its interior. One of the five localized areas on the nucleus which dominate the activity observed appears to be uniquely responsible for the initiation of CN-shell boundaries which propagate through the coma, and may be indicative of either large-scale chemical inhomogeneity or a surface region with unusual physical structure.

Belton, Michael J. S.↗
NASA NTRS2004

Suzaku Reveals He-burning Products in the X-ray Emitting Planetary Nebula BD +30deg 3639

BD +30deg 3639, the brightest planetary nebula at X-ray energies, was observed with Suzaku, an X-ray observatory launched on 2005 July 10. Using the X-ray Imaging Spectrometer, the K-lines from C VI, O VII, and O VIII were resolved for the first time, and C/O, N/O, and Ne/O abundance ratios determined. The C/O abundance ratio exceeds the solar value by nearly two orders of magnitude, and that of Ne/O by at least a factor of 5. These results indicate that the X-rays are emitted mainly by helium shell-burning products.

Murashima, M.↗
NASA NTRS1998

Development of Paper Products from Dried Sweetpotato Stems and Peanut Shells

One of the goals of NASA's Advanced Life Support Program (ALS) for sustaining human life in space is to achieve a closed system in plant production and usage. That all inedible plant parts should be recycled or used in some way. A Tuskegee University team researching sweetpotato and peanut for ALS has developed paper products from dried sweet-potato stems and peanut shells. In this study, the sweet-potato stems and peanut shells were soaked separately in water for 48 hours. After 48 hours, researchers manually separated the pulp and the unusable parts. To form the paper, 160 g of pulp and water mixture was poured through a 15.1 cm (diameter) filtration funnel and the pulp was trapped on 15 cm (diameter) filter paper. The filter paper and pulp were dried in an air oven, and the filter paper was removed, An examination under a scanning electron microscope showed that the sweet-potato paper was composed of "fibers", whereas the peanut shell paper was composed of "blocks". Results of physical testing showed that the sweet-potato stem paper was stronger than the peanut shell paper. It is anticipated that there may be other uses of these products such as writing paper, bags and packaging material. Because of its biodegradability, it can be incorporated into the resource recycling system at the end of its use.

R McConnell↗
NASA NTRS1980

Xenon, osmium, and lead formed in O-shells and C-shells of massive stars

In this paper it is shown that the explosive products from O-shells of massive stars which contain Xe-124 with large overproduction factors do not contain any of the naturally occurring isotopes of Os and Pb. Further, it is shown that the explosive products from C-shells (explosive carbon burning) do contain Os and Pb along with Xe which is strongly enriched in r-Xe of anomalous isotopic composition. The composition of Os in this matter is probably s-like rather than r-like. Pb in this matter is enriched in Pb-208. The results and arguments of this paper have implications for studies of isotopic compositions of Xe, Os, and Pb in residues of the Allende and other carbonaceous chondrites.

Heymann, D.↗
NASA NTRS1986

Experiments on annular liquid jet instability and on the formation of liquid shells

An annular jet flow of liquid surrounding a flow of gas at its core is extremely unstable. Experiments are described in which such a flow is generated by an annular nozzle operated at fairly specific conditions. It is shown that periodic, axisymmetric oscillations arise spontaneously within the cylindrical sheet emerging from the nozzle and grow with such rapidity along the axial dimension that a sealing-off and encapsulation of the core gas occurs within a few jet diameters. This is closely followed by a pinchoff of the liquid between adjacent bubbles. The liquid shells set free thereby assume spherically symmetric form under capillary forces, and each contains a precisely uniform measure of gas and of liquid on account of the extremely high frequency-stability of the process. Description is given of the fluid dynamic processes by which the shells are formed, and mention is made of exploiting the instability for the production of rigid shells for technological applications.

Kendall, J. M.↗
NASA NTRS1972

Effect of a circular hole on the buckling of cylindrical shells loaded by axial compression.

An experimental and analytical investigation of the effect of a circular hole on the buckling of thin cylindrical shells under axial compression was carried out. The experimental results were obtained from tests performed on seamless electroformed copper shells and Mylar shells with a lap joint seam. These results indicated that the character of the shell buckling was dependent on a parameter which is proportional to the hole radius divided by the square root of the product of the shell radius and thickness. For small values of this parameter, there was no apparent effect of the hole on the buckling load. For slightly larger values of the parameter, the shells still buckled into a general collapse configuration, but the buckling loads were sharply reduced as the parameter increased. For still larger values of the parameter, the buckling loads were further reduced, and the shells buckled into a stable local buckling configuration.

Starnes, J. H., Jr.↗
NASA NTRS2006

Making Activated Carbon by Wet Pressurized Pyrolysis

A wet pressurized pyrolysis (wet carbonization) process has been invented as a means of producing activated carbon from a wide variety of inedible biomass consisting principally of plant wastes. The principal intended use of this activated carbon is room-temperature adsorption of pollutant gases from cooled incinerator exhaust streams. Activated carbon is highly porous and has a large surface area. The surface area depends strongly on the raw material and the production process. Coconut shells and bituminous coal are the primary raw materials that, until now, were converted into activated carbon of commercially acceptable quality by use of traditional production processes that involve activation by use of steam or carbon dioxide. In the wet pressurized pyrolysis process, the plant material is subjected to high pressure and temperature in an aqueous medium in the absence of oxygen for a specified amount of time to break carbon-oxygen bonds in the organic material and modify the structure of the material to obtain large surface area. Plant materials that have been used in demonstrations of the process include inedible parts of wheat, rice, potato, soybean, and tomato plants. The raw plant material is ground and mixed with a specified proportion of water. The mixture is placed in a stirred autoclave, wherein it is pyrolized at a temperature between 450 and 590 F (approximately between 230 and 310 C) and a pressure between 1 and 1.4 kpsi (approximately between 7 and 10 MPa) for a time between 5 minutes and 1 hour. The solid fraction remaining after wet carbonization is dried, then activated at a temperature of 500 F (260 C) in nitrogen gas. The activated carbon thus produced is comparable to commercial activated carbon. It can be used to adsorb oxides of sulfur, oxides of nitrogen, and trace amounts of hydrocarbons, any or all of which can be present in flue gas. Alternatively, the dried solid fraction can be used, even without the activation treatment, to absorb oxides of nitrogen.

Fisher, John W.↗