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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Enrichment of very heavy nuclei in the composition of solar accelerated particles.

Measurement of the abundances of the nuclei C, N, O, Ne, Mg, Si, Ar, and Ca and the group Cr-Co relative to oxygen from seven solar energetic-particle events in the energy range from about 14 to 61 MeV per nucleon with a solid-state detector telescope on the OGO-5 satellite, 1968-1971. The differential energy spectra of O (14 to 29 MeV per nucleon) and Cr-Co (3 to 61 MeV per nucleon) have a spectral index of about (-3) for a power law in kinetic energy. The relative abundances of C, N, O, and Ne are in excellent agreement with emulsion studies. However, when compared with the solar photospheric and coronal abundances, the OGO-5 measurements show a large enhancement of relative abundances beginning with Si, and extending to the Cr-Co group. The enhancement over the solar and universal abundances is in rough agreement with the composition of the galactic cosmic radiation.

Mogro-Campero, A.↗
NASA NTRS1973

Enriched aluminide coatings for dispersion strengthened nickel materials

Improved aluminide/barrier coating combinations for dispersion strengthened nickel materials were investigated. The barrier materials involved alloys with refractory metal content to limit interdiffusion between the coating and the substrate, thereby minimizing void formation. Improved aluminide coatings involved the dispersion of aluminum-rich compounds. Coatings were tested in argon at 1533 K (2300 F) for 100 hours and in cyclic oxidation at 1422 K (2100 F). Two coatings on TDNiCr completed 300 hours of oxidation testing, none on TDNi. Selected coating combinations were evaluated in Mach 1 burner rig testing using JP-4 fuel and air at 1422 K (2100 F) and 1477 K (2200 F) for 350 and 100 hours, respectively. Static oxidation in 1-hour cycles was conducted at 1533 K (2300 F) for 100 hours. For comparison purposes a physical vapor deposition (PVD) NiCrAlY coating was tested concurrently. Only the NiCrA1Y coating survived the 1477 K (2200 F)/100-hour burner rig test and 275 hours of the 350-hour 1422 K (2100 F) test. Elevated temperature exposure reduced room temperature tensile properties but had little effect on elevated temperature properties.

Levinstein, M. A.↗
NASA NTRS1974

Polymer compositions suitable for use in enriched oxygen atmospheres

Three organic polymer systems are based on copolymer of chlorotrifluoroethylene, ethylene, and tin-based flame retardants. Fourth system is copolymer of chlorotrifluorethylene and tetrafluoroethylene. This system contains no stabilizers of flame retardant additives.

Schule, E. C.↗
NASA NTRS1973

Development of modified poly(perfluoropropyleneoxide) urethane systems for use in liquid oxygen and in enriched 100 percent oxygen atmosphere

This program consisted of two separate though related phases. The initial phase was directed toward improving the mechanical and adhesive properties of the very highly fluorinated-polyurethane resin system derived from the hydroxyl-terminated polyperfluoropropylene oxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate. Various new curing agents for this system were investigated, with the goal of providing a more thermally stable crosslink (cure) mechanism to provide wider applicability and fuller utilization of the outstanding oxygen resistance of the PFPO system. Complete resistance to liquid- and gaseous-oxygen impact at presures as high as 1035 N/sq cm were attained with the use of the PFPO resin castings. The second corollary phase was directed toward investigating the feasibility and optimization of the allophanate cured, urethane extended polymer derived from hydroxyl-terminated polyperfluoropropyleneoxide and 6-chloro-2,4,5-trifluoro-m-phenylene diisocyanate, as the adhesive system for use in a weld-bond configuration for liquid oxygen tankage. The synthesis and application procedures of the adhesive system to insure liquid oxygen compatibility (under 10 kg-m loading), and the development of procedures and techniques to provide high quality weld-bonded joint configurations were studied.

Harrison, E. S.↗
NASA NTRS1978

Hydrogen enrichment of synthetic fuel

Synthetic gas may be produced at lower cost and higher efficiency by using outside source of hydrogen. Method is compatible with same temperatures and pressures as shift reaction. Process increases efficiency by using less coal and water to provide equal amount of synthetic gas.

Jay, C. G.↗
NASA NTRS1978

Enriched gas in clusters and the dynamics of galaxies and clusters Implications for theories of galaxy formation

Recent observations of the rotation of elliptical galaxies and of X-ray clusters are cited in developing a simple model for the formation of elliptical and spiral galaxies; the model provides for continuous galaxy formation from redshift values of about 100 onwards. In particular, it is argued that a fundamental alteration in the manner in which cosmic material fragmented to form stellar objects took place at a redshift value of approximately five. This change of regime may be employed to explain the formation of Population I disks, the origin of hot intracluster gas, the galaxy luminosity function, and the mass-to-light ratio stratification of galaxies.

Binney, J.↗
NASA NTRS1978

Hydrogen enrichment for low-emission jet combustion

Simultaneous gaseous pollutant emission indexes (g pollutant/kg fuel) for a research combustor with inlet air at 120,900 N/sq m (11.9 atm) pressure and 727 K (849 F) temperature are as low as 1.0 for NOx and CO and 0.5 for unburned HC. Emissions data are presented for hydrogen/jet fuel (JP-5) mixes and for jet fuel only for premixed equivalence ratios from lean blowout to 0.65. Minimized emissions were achieved at an equivalence ratio of 0.38 using 10-12 mass percent hydrogen in the total fuel to depress the lean blowout limit. They were not achievable with jet fuel alone because of the onset of lean blowout at an equivalence ratio too high to reduce the NOx emission sufficiently.

Clayton, R. M.↗
NASA NTRS1979

Reproductive adaptation in Drosophila exposed to oxygen-enriched atmospheres

Ten successive generations of a Drosophila melanogaster population were exposed to an atmospheric mix of 50% oxygen/50% nitrogen at standard pressure. This atmospheric mix has been shown to be toxic to this species and causes significantly shortened life span. By the fifth generation, survivorship and life span for the first 25-30 days were identical to control populations and total life span was shorter by only a few days. Egg-laying rates were stable in the experimental populations but below those of the controls. Hatching success was identical between experimental and control populations. Even though the egg-laying rates were lower in 50% oxygen, it was concluded that the population had adapted and could maintain a stable population in these conditions. The near-normal life spans, normal hatching rates, and overall population stability, exhibited following five generations of adaptation, were considered sufficient to allow continued reproduction in spite of a reduced egg-laying rate.

Kloek, G.↗
NASA NTRS1984

Formation of chondrules by drag heating in dust-enriched environments

The solar system which had a beginning, 4.6 billion years ago is discussed. The atoms that make up the solar system are much older than that, however: they were also part of the universe that existed before the solar system formed. The presence and location of the atoms of silicon, iron, calcium, that make up the Earth and other planets before there was a solar system is questioned. Astronomical it is shown that they existed in tiny dust grains which, along with molecules of gas, wandered about in the vast reaches of space between the stars of our galaxy. The solar system was formed when one particular cloud of interstellar dust and gas became dense enough to be gravitationally unstable: the gravitational pull that dust grains and gas molecules exerted on one another caused the cloud to collapse.

Wood, J. A.↗
NASA NTRS1985

Fuel-rich catalytic combustion: A soot-free technique for in situ hydrogen-like enrichment

An experimental program on the catalytic oxidation of iso-octane demonstrated the feasibility of the two-stage combustion system for reducing particulate emissions. With a fuel-rich (phi = 4.8 to 7.8) catalytic combustion preburner as the first stage the combustion process was soot free at reactor outlet temperatures of 1200 K or less. Although soot was not measured directly, its absence was indicated. Reaction products collected at two positions downstream of the catalyst bed were analyzed on a gas chromatograph. Comparison of these products indicated that pyrolysis of the larger molecules continued along the drift tube and that benzene formation was a gas-phase reaction. The effective hydrogen-carbon ratio calculated from the reaction products increased by 20 to 68 percent over the range of equivalence ratios tested. The catalytic partial oxidation process also yielded a large number of smaller-containing molecules. The fraction of fuel carbon in compounds having two or fewer carbon atoms ranged from 30 percent at 1100 K to 80 percent at 1200 K.

Brabbs, T. A.↗