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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Stress corrosion in titanium alloys and other metallic materials

Multiple physical and chemical techniques including mass spectroscopy, atomic absorption spectroscopy, gas chromatography, electron microscopy, optical microscopy, electronic spectroscopy for chemical analysis (ESCA), infrared spectroscopy, nuclear magnetic resonance (NMR), X-ray analysis, conductivity, and isotopic labeling were used in investigating the atomic interactions between organic environments and titanium and titanium oxide surfaces. Key anhydrous environments studied included alcohols, which contain hydrogen; carbon tetrachloride, which does not contain hydrogen; and mixtures of alcohols and halocarbons. Effects of dissolved salts in alcohols were also studied. This program emphasized experiments designed to delineate the conditions necessary rather than sufficient for initiation processes and for propagation processes in Ti SCC.

Harkins, C. G.↗
NASA NTRSDate not supplied

Atmospheric, Non-Combusting Droplet Sizing and Spray Imaging Results From a Non-Proprietary Aero Gas Turbine Engine Pressure Swirl Atomizer using Shadowgraphy and Planar Laser Scatter

Members from industry and federal agencies of the United States have developed a collaborating group focused on improving the understanding of the atomization processes common to gas turbine engines. The group is aimed on providing high quality data using x-ray diagnostics in the internal geometry and the near-field dense spray as well as optical diagnostics in the visible spectrum, downstream of the nozzle. This paper reports results from one of the two non-proprietary injectors designs from the group: the primary-secondary injector. In particular, we characterize the spray from only the primary, pressure-swirl atomizing circuit using water through the nozzle. We observed Sauter mean diameter decreased with increased water pressure drop across the nozzle. SMD was also collected at three axial distances and showed decreased size with distance from the nozzle. Planar laser sheet droplet scattering provided qualitative assessment of the spray. Higher water pressure drops provided better atomization than lower pressure drops. The addition of swirling air flow through the injector alleviates and improves the atomization quality, particularly at the lower water pressure drops.

optical diagnostics↗
NASA NTRS1967

Glancing incidence telescope for far ultraviolet and soft X-rays

Glancing-incidence telescope makes observations of distant celestial radiant bodies at wavelengths in the spectral region between 3 and 500 angstroms. The device can be used as a fore-optics system for a laboratory extreme ultraviolet spectrometer, or for the collection or imaging of thermal neutrons.

Neupert, W. M.↗
NASA NTRS1971

A study of two flares on 8 July 1968 in the light of their ionospheric effects.

Detailed study of the observed ionospheric effects of the X-ray flare on July 8, 1968, which was of considerable importance both from the ionospheric and solar physics point of view. The associated optical flare was of importance 3B. The ionospheric effects were examined in order to derive a suitable physical model of flare-induced ionization below 100 km, and hence to estimate the spectral characteristics of the ionizing radiations from the observed SID s. The electron loss coefficients below 70 km height calculated from the formula developed in the analysis are in agreement with available data.

Sengupta, P. R.↗
NASA NTRS1971

Studies of positive-ion composition in the equatorial D-region ionosphere.

Evaluation of two daytime D-region positive-ion composition measurements performed at Thumba, India, for solar zenith angles of 53.2 and 27.8 deg. Comparison of upleg ram with downleg wake data shows a large increase in the concentration of heavy ions 48(+), NO(+) . H2O; 55(+), H3O(+) . (H2O)2; and M(+) greater than 65(+) for the downleg reduced shock condition. Peak concentrations of 48(+) and 55(+) occur at unit optical depth for Lyman alpha radiation. The ion 37(+), H3O(+) . H2O, is dominant for chi = 27.8 deg, but not for chi = 53.2 deg, consistent above 80 km with an origin from the X-ray production of O2(+). Laboratory measurements have shown that the ion, NO(+), can be transferred to heavy hydrates 48(+), 55(+), and M(+) greater than 65(+) by a reaction chain starting with NO(+) + X + M = NO(+) . X + M, where X can be O2, N2, CO2 or a combination of all three, depending on the rate of reaction. This chain, together with a similar reaction scheme starting with O2(+) and ending in 19(+), 37(+), and heavier clusters, is used to provide a consistent explanation for the hydrated ions observed in the D region.

Goldberg, R. A.↗
NASA NTRS1969

Dual purpose optical instrument capable of simultaneously acting as spectrometer and diffractometer

A dual purpose optical instrument is described capable of simultaneously acting as a spectrometer and diffractometer to respectively perform elemental and structural analysis of an unknown sample. The diffractometer portion of the instrument employs a modified form of Seeman-Bohlin focusing which involves providing a line source of X-rays, a sample, and a detector, all on the same focal circle. The spectrometer portion of the instrument employs a fixedly mounted X-ray energy detector mounted outside of the plane of the focal circle.

Dasgupta, K.↗
NASA NTRS2020

The Slow Demise of the Long-Lived Sn 2005ip

The Type IIn supernova (SN IIn) 2005ip is one of the most well-studied and long-lasting examples of an SN interacting with its circumstellar environment. The optical light curve plateaued at a nearly constant level for more than five years, suggesting ongoing shock interaction with an extended and clumpy circumstellar medium (CSM). Here, we present continued observations of the SN from ∼1000 to 5000 d post-explosion at all wavelengths, including X-ray, ultraviolet, near-infrared (NIR), and mid-infrared. The UV spectra probe the pre-explosion mass loss and show evidence for CNO processing. From the bolometric light curve, we find that the total radiated energy is in excess of 10 50 erg, the progenitor star’s pre-explosion mass-loss rate was >~ 1 × 10 −2 Mꙩ yr −1 , and the total mass lost shortly before explosion was >~1Mꙩ, though the mass lost could have been considerably larger depending on the efficiency for the conversion of kinetic energy to radiation. The ultraviolet through NIR spectrum is characterized by two high-density components, one with narrow high-ionization lines, and one with broader low-ionization H I, He I, [OI], Mg II, and Fe II lines. The rich Fe II spectrum is strongly affected by Lyα fluorescence, consistent with spectral modelling. Both the Balmer and He I lines indicate a decreasing CSM density during the late interaction period. We find similarities to SN 1988Z, which shows a comparable change in spectrum at around the same time during its very slow decline. These results suggest that, at long last, the shock interaction in SN 2005ip may finally be on the decline.

stars↗
NASA NTRS1971

Photoemf in cadmium sulfide

Theoretical and experimental investigations on CdS single crystals and CuxS:CdS photovoltaic cells prepared from CdS single crystals by a chemical-dip procedure are described. The studies are aimed at clarifying cell mechanisms which affect key cell properties (efficiency, reliability, and lifetime) by examining the properties of intrinsic and extrinsic defects in the junction and surface regions and their effects on carrier transport through these regions. The experimental research described includes studies of thermal, infrared, and field quenching of acceptor-doped CdS crystals; investigation of optical and electrical properties of CuxS:CdS photovoltaic cells (current-voltage characteristics, spectral distribution of photocurrent and photovoltage) and the dependence of these properties on temperature and light intensity; measurement of changes, as a result of heat treatment in ultrahigh vacuum, in the spectral distribution of photoconductivity at room temperature and liquid nitrogen temperature, the luminescence spectrum at liquid nitrogen temperature, and the thermally stimulated current curves of CdS crystals; determination of the effect of irradiation with 150 keV (maximum) X-rays on the spectral distribution of photoconductivity and thermally-stimulated current of CdS crystals; and studies of the effect of growth conditions on the photoconductive properties of CdS crystals.

Boeer, K. W.↗
NASA NTRSDate not supplied

The HEROIX Broadband X-Ray Space Telescope Mission Concept

The High EneRgy Observatory for Imaging X-rays (HEROIX) Medium-Class Mission concept envisions a next-generation broadband X-ray observatory designed to meet the astrophysics community’s need for high-angular-resolution studies of the Cosmic X-ray Background. Building on the science legacy of NASA’s NuSTAR mission and more than 30 years of advances in replicated NiCo shell technology at NASA Marshall, HEROIX proposes a space observatory comprising four co-aligned telescopes achieving 5 arcsecond half-power diameter (HPD) angular resolution. This capability, approached by the resolution demonstrated in the FOXSI-4 sounding rocket mission and under development through the SuperHERO balloon mission, will be extended to energies up to 80 keV through multilayer coatings. Marshall’s inhouse precision optics manufacturing enables an integrated effective area of 380 cm² at 30 keV, which, combined with high-resolution optics, opens new windows into extreme astrophysical non-thermal processes.

Nick Thomas↗
NASA NTRS1969

X-ray pulsar in the Crab Nebula.

X ray pulsations in Crab Nebula at frequency closely matching radio and optical pulsations, noting energy distribution

Chubb, T. A.↗
NASA NTRS1972

Noncontacting device to indicate deflection of turbopump internal rotating parts

Phase 2 (development) which was concluded for the ultrasonic Doppler device and the light-pipe-reflectance device is reported. An ultrasonic Doppler breadboard system was assembled which accurately measured runout in the J-2 LOX pump impeller during operation. The transducer was mounted on the outside of the pump volute using a C-clamp. Vibration was measured by conducting the ultrasonic wave through the volute housing and through the fluid in the volute to the impeller surface. The impeller vibration was also measured accurately using the light-pipe probe mounted in an elastomeric-gland fitting in the pump case. A special epoxy resin developed for cryogenic applications was forced into the end of the fiber-optic probe to retain the fibers. Subsequently, the probe suffered no damage after simultaneous exposure to 2150 psi and 77 F. Preliminary flash X-radiographs were taken of the turbine wheel and the shaft-bearing-seal assembly, using a 2-megavolt X-ray unit. Reasonable resolution and contrast was obtained. A fast-neutron detector was fabricated and sensitivity was measured. The results demonstrated that the technique is feasible for integrated-time measurements requiring, perhaps, 240 revolutions to obtain sufficient exposure at 35,000 rpm. The experimental verification plans are included.

Hamilton, D. B.↗
NASA NTRS1972

The optical polarization of Scorpius X-1.

The X-ray source Sco X-1 is known to have a slight linear polarization in visible light. An investigation was conducted to determine whether the origin of the polarization is intrinsic to the source or interstellar. No evidence could be found for unusual polarization properties in Sco X-1 that would point to an intrinsically polarized source, although this cannot be excluded. It is pointed out that the case for interstellar polarization would become very strong if stars in the immediate vicinity are found to be polarized with the same position angle.

Landstreet, J. D.↗