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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 685 records · Page 38
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Development of Skylab medical equipment and flight preparations

The major medical systems in the Skylab orbital workshop are described. They comprise the food system, the waste management system, operational bioinstrumentation, personal hygiene, gas sampling, an inflight medical support system, and a cardiovascular counterpressure garment. Life sciences experiments carried out aboard Skylab are also reviewed; these include an ergometer and metabolic analyzer, a lower-body negative pressure device, an electrode harness and body temperature probe, a blood pressure cuff, a leg volume measuring band, sleep studies, a body-mass measuring device, a rotating litter chair, a blood sample processor, and small-mass measuring apparatus. All performance requirements were met with the equipment, and no failures were encountered.

Johnston, R. S.↗
NASA NTRS1975

The preparation and properties of aluminum nitride films

Aluminum nitride films have been deposited on silicon substrates at 800-1200 C by the pyrolysis of an aluminum trichloride-ammonia complex, AlCl3.3NH3, in a gas flow system. The deposit was transparent, tightly adherent to the substrate, and was confirmed to be aluminum nitride by X-ray and electron diffraction techniques. The deposited aluminum nitride films were found to be polycrystalline with the crystallite size increasing with increasing temperature of deposition. Other properties of aluminum nitride films relevant to device applications, including density, refractive index, dissolution rate, dielectric constant, and masking ability, have been determined. These properties indicate that aluminum nitride films have potential as a dielectric in electronic devices.

Chu, T. L.↗
NASA NTRS1974

Preservation of lunar core samples - Preparation and interpretation of three-dimensional stratigraphic sections

Preservation and analysis of core samples collected from the lunar regolith are discussed. The objectives of core sampling are described together with the core-sampling equipment used in the Apollo program. The effects of disaggregation in core samples are summarized, and ways to preserve the stratigraphy in these samples are reviewed, particularly partial impregnation of samples with polybutyl methacrylate. It is shown that stratigraphic sections preserved in this way reveal individual fragments of the regolith in their original positions, primary and secondary depositional structures related to lunar processes, and the nature and extent of deformations caused by sampling equipment. It is concluded that since the core sedimentary structures indicate complex three-dimensional variations in the regolith, quantitative models of regolith evolution must allow for distinctive local histories as well as irregular reworking and deposition events due to impact processes.

Fryxell, R.↗
NASA NTRS1975

Preliminary study of oxide-dispersion-strengthened B-1900 prepared by mechanical alloys

An experimental oxide dispersion strengthened (ODS) alloy based on the B-1900 composition was produced by the mechanical alloying process. Without optimization of the processing for the alloy or the alloy for the processing, recrystallization of the extruded product to large elongated grains was achieved. Materials having grain length-width ratios of 3 and 5.5 were tested in tension and stress-rupture. The ODS B-1900 exhibited tensile strength similar to that of cast B-1900. Its stress-rupture life was lower than that of cast B-1900 at 760 C. At 1095 C the ODS B-1900 with the higher grain length-width ratio (5.5) had stress-rupture life superior to that of cast B-1900. It was concluded that, with optimization, oxide dispersion strengthening of B-1900 and other complex cast nickel-base alloys has potential for improving high temperature properties over those of the cast alloy counterparts.

Glasgow, T. K.↗
NASA NTRS1976

Sample preparation of metal alloys by electric discharge machining

Electric discharge machining was investigated as a noncontaminating method of comminuting alloys for subsequent chemical analysis. Particulate dispersions in water were produced from bulk alloys at a rate of about 5 mg/min by using a commercially available machining instrument. The utility of this approach was demonstrated by results obtained when acidified dispersions were substituted for true acid solutions in an established spectrochemical method. The analysis results were not significantly different for the two sample forms. Particle size measurements and preliminary results from other spectrochemical methods which require direct aspiration of liquid into flame or plasma sources are reported.

Chapman, G. B., II↗
NASA NTRS1976

Prepared comment on the cone transition Reynolds number data correlation study

A sharp, smooth, 10-deg-included-angle cone was tested on twenty-one major wind tunnels of the United States and Western Europe to obtain correlation data on the effect of acoustic disturbances in wind tunnel flow on boundary layer transition Reynolds number. The cone is planned to be flight tested in order to obtain a basis of reference for the wind tunnel data over a nominal range of Mach numbers from 0.4 to approximately 2.0. Wind tunnel data obtained over a Mach number range from 0.2 to 4.6 are broadly characterized according to wind tunnel test section geometry and, in turn, to the types of acoustic disturbances associated with the geometry.

Dougherty, N. S., Jr.↗
NASA NTRS1975

Preparation of eutectic superalloys by EFG

An attempt was made to produce airfoil shaped bars of three different eutectic superalloys by means of the edge-defined, film-fed growth (EFG) method. The alloys used were a gamma + delta Ni-Cb alloy, a gamma/gamma prime + delta Ni-Cb-Al alloy and a Co-TaC alloy containing Ni and Cr. The development of a new die material was essential in the investigation since these alloys are reactive toward known die materials. Tantalum carbide was selected as a die material because it exhibited spontaneous capillary rise and slow rate of degradation in the liquid metals. Eutectic bars up to 1 mm thick and 6 mm wide were grown from TaC dies in order to determine the growth characteristics and the thermal gradient. Large bars of the gamma/gamma prime + delta alloy were grown and tensile tested. A die with a blind central cavity was designed and several hollow, tear-shaped bars were grown.

Hurley, G. F.↗
NASA NTRS1976

Engineering support for the Space Processing Application Rocket /SPAR/ project - Preparation for effective Shuttle utilization

Sounding rockets are being used in the Space Processing Program to develop the scientific, engineering, and management expertise to effectively use the Shuttle. An extensive vehicle selection study was necessary to optimize the payload weight, cost factors, and low-g time. The vehicle and subsystem development for each of the flight vehicles is described along with analyses and programmatic considerations peculiar to the Space Processing Program. Several early Space Processing payloads are described along with available flight results.

Ott, R. H.↗
NASA NTRS1976

Preparation and characterization of methacrylate hydrogels for zeta potential control

A technique based on the measurement of streaming potentials has been developed to evaluate the effects of hydrophilic coatings on electroosmotic flow. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of glass capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming potential measurements is discussed. Various silane adhesion promoters exhibited only a slight decrease in streaming potential. A coating utilizing a glycidoxy silane base upon which methylcellulose is applied affords a six-fold decrease over uncoated tubes. Hydrophilic methacrylate gels show similar streaming potential behavior, independent of the water content of the gel. By introduction of positive or negative groups into the hydrophilic methacrylate gels, a range of streaming potential values are obtained having absolute positive or negative signs.

Gregonis, D. E.↗
NASA NTRS1977

Process for preparing liquid metal electrical contact device

The parts of an electrical contact device are treated by sputter etching to remove the parent metal oxide. Prior to exposure of the electrodes to any oxygen, a sacrificial metal is sputter deposited on the parts. Preferably this sacrificial metal is one that oxidizes slowly and is readily dissolved by the liquid metal. The sacrificial metal may then be removed from unwanted areas. The remainder of the ring and the probe to be wet by the liquid metal are submerged in the liquid metal or the liquid metal is flushed over these areas, preferably while they are being slightly abraded, unitl all the sacrificial material on these portions is wet by the liquid metal. In doing so the liquid metal dissolves the sacrificial metal and permanently wets the parent metal. Preferred materials used in the process and for the electrodes of electrical contact devices are high purity (99.0%) nickel or AISI type 304 stainless steel for the electrical contact devices, gallium as the liquid metal, and gold as the sacrificial material.

Lovell, R. R.↗
NASA NTRS1977

Heterogeneous chemical reactions: Preparation of monodisperse latexes

It is demonstrated that a photoinitiated emulsion polymerization can be carried out to a significant conversion in a SPAR rocket prototype polymerization vessel within the six minutes allowed for the experiment. The percentage of conversion was determined by both dilatometry and gravimetric methods with good agreement. The experimental results lead to the following conclusions: (1) emulsion polymerizations can be carried out to conversions as high as 75%, using a stable micellized styrene-SLS system plus photoinitiator; (2) dilatometry can be used to accurately determine both the rate and conversion of polymerization; (3) thermal expansion due to the light source and heat of reaction is small and can be corrected for if necessary; (4) although seeded emulsion polymerizations are unfavorable in photoinitiation, as opposed to chemical initiation, polymerizations can be carried out to at least 15% conversion using 7940A seed particles, with 0.05% solids; and (5) photoinitiation should be used to initiate polymerization in the SPAR rocket experiments because of the mechanical simplicity of the experiment.

Vanderhoff, J. W.↗
NASA NTRS1976

Candidate space processing techniques for biomaterials other than preparative electrophoresis

The advantages of performing the partition and countercurrent distribution (CCD) of cells in phase separated aqueous polymer systems under reduced gravity were assessed. Other possible applications considered for the space processing program include the freezing front separation of cells, adsorption of cells at the air-water interface, and the macrophage electrophoretic mobility test for cancer.

Brooks, D. E.↗
NASA NTRS1977

Application of remote sensing in South Dakota to provide accurate inventories of agricultural crops, enhance contrast in photographic products, monitor rangeland habitat loss, map Aspen, and prepare hydrogeologic surveys

The author has identified the following significant results. Digital analysis of LANDSAT CCT's indicated that two discrete spectral background zones occurred among the five soil zone. K-CLASS classification of corn revealed that accuracy increased when two background zones were used, compared to the classification of corn stratified by five soil zones. Selectively varying film type developer and development time produces higher contract in reprocessed imagery. Interpretation of rangeland and cropped land data from 1968 aerial photography and 1976 LANDSAT imagery indicated losses in rangeland habitat. Thermal imagery was useful in locating potential sources of sub-surface water and geothermal energy, estimating evapotranspiration, and inventorying the land.

Myers, V. I.↗