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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Volumetric pattern analysis of airborne antennas

By blending together the roll and elevation plane high-frequency solutions, a very efficient technique has been developed for the volumetric pattern analysis of antennas mounted on the fuselage of a generalized aircraft. The fuselage is simulated by an infinitely long, perfectly conducting, elliptic cylinder in cross section and a composite elliptic cylinder in profile. The wings, nose section, stabilizers, and landing-gear doors may be modeled by finite flat or bent plates. Good agreement with accurate scale model measurements has been obtained for a variety of airborne antenna problems.

Yu, C. L.↗
NASA NTRS1980

No-reheat air-conditioning

Air conditioning system, for environmentally controlled areas containing sensitive equipment, regulates temperature and humidity without wasteful and costly reheating. System blends outside air with return air as dictated by various sensors to ensure required humidity in cooled spaces (such as computer room).

Obler, H. D.↗
NASA NTRS1978

Phosphorylated epoxy adhesives

Fire retardant adhesives for aircraft interiors are developed. Monomers, epoxy synthesis, diamine synthesis, acrylic modified epoxy, and phosphorylated amine epoxy blends are examined.

Bilow, N.↗
NASA NTRS1978

Flight experience with manually controlled unconventional aircraft motions

A modified YF-16 aircraft was used to flight demonstrate decoupled modes under the USAF Fighter Control Configured Vehicle (CCV) Program. The direct force capabilities were used to implement seven manually controlled unconventional modes on the aircraft, allowing flat turns, decoupled normal acceleration control, independent longitudinal and lateral translations, uncoupled elevation and azimuth aiming, and blended direct lift. This paper describes the design, development, and flight testing of these control modes. The need for task-tailored mode authorities, gain-scheduling and selected closed-loop design is discussed.

Barfield, A. F.↗
NASA NTRS1977

Configuration development study of the X-24C hypersonic research airplane

Bottom line results were made of a three-phase study to determine the feasibility of designing, building, and operating, and maintaining an air-launched high performance aircraft capable of cruising at speeds up to Mach 8 for short durations. The results show that Lockalloy heat-sink structure affords the capability for a 'work-horse' vehicle which can serve as an excellent platform for this research. It was further concluded that the performance of a blended wing body configuration surpassed that of a lifting body design for typical X-24C missions. The cost of a two vehicle program, less engines, B-52 modification and contractor support after delivery, can be kept within $70M (in Jan. 1976 dollars).

Combs, H. G.↗
NASA NTRS1979

Solar cell with improved N-region contact and method of forming the same

An improved solar cell, and method of forming the same are disclosed. It is characterized by a semiconductor silicon wafer of P-type material having diffused therein a shallow N-type region. A sintered silver contact is affixed to the surface of the N-type region at the outer surface. The improved solar cell is formulated from silver powder blended with silver metaphosphate for establishing a zone of increased carrier concentration. An aluminum or silver-aluminum alloy contact is affixed to the P-type wafer at the outer surface opposite the N-type region.

Bube, K. R.↗
NASA NTRS1979

Feasibility study on the development of tough, moisture-resistant laminating resins

The potential of cyanate resins as replacement for epoxy resins in composites with graphite fiber reinforcement was investigated in an effort to provide improved moisture resistance and toughness in laminating systems at a projected cost, handleability, and processing requirements equivalent to 400 K (260 F) curing epoxies. Monomer synthesis, formulation, blending, resin preparation, catalysis studies, prepreg preparation, laminate fabrication, and testing are discussed. A graphite fiber reinforced laminate was developed with 95 percent retention of the original 363 K (180 F) flexural strength and 70 percent retention of the 363 K (180 F) short beam shear strength after 500 hour exposure to 95 + 7 relative humidity at 324 K (120 F).

Brand, R. A.↗
NASA NTRS1979

X-ray evidence for electron-ion equilibrium and ionization nonequilibrium in young supernova remnants

The A-2 spectroscopy experiment on HEAO 1 detected X-ray emission up to 25 keV from the supernova remnants Cas A and Tycho. The spectra must include continuum components with effective temperature equivalent or 10 to the 8th power K which could arise from optically thin plasmas in the collisionless shock fronts. This is the first indication of electron-ion temperature equilibrium in the expanding shell of young remnants. Measurements of the equivalent widths of the K alpha and K beta iron line blends in Cas A, show that their ratio is not compatible with the measured X-ray temperature in the collisional ionization equilibrium model. The search for hard X-ray pulsars in both remnants was unsuccessful.

Pravdo, S. H.↗
NASA NTRS1978

Temperature and ionization balance dependence of O VII line ratios

The forbidden-plus-intersystem to resonance line ratio (G) for the heliumlike ion O VII is calculated, taking into account cascades, blended satellite lines, and radiative plus dielectric recombination. It is noted that G is of particular use for investigating radiative-transfer effects and nonequilibrium ionization in the solar corona and that the calculations are applicable to a low-density optically thin Maxwellian plasma. The temperature dependence of G is considered for the case of a steady-state equilibrium plasma, and the effect of departures from ionization equilibrium on G is examined. It is found that G is quite insensitive to temperature over the range from 600,000 to 6 million K for a steady-state plasma, but that recombinations may be suppressed or dominant, depending on the relative abundance of O VIII, for a plasma in which the state of ionization is not in equilibrium with the electron temperature. This latter effect is shown to be capable of causing large variations in G that are dependent on electron temperature.

Acton, L. W.↗
NASA NTRS1978

Use of radio equipment for Space Shuttle navigation

Space Shuttle navigation is defined, in a narrow sense, as the task of maintaining adequate knowledge of vehicle position and velocity. The state of the Orbiter in terms of this goal is described by a vector of at least six elements, three for position and three for velocity, at a given time. These are referred to as the 'state vector' or simply as the state. Shuttle navigation will relay on a blend of ground-based and onboard systems. The onboard systems will be capable of state propagation at all times and will perform state determination during the latter part of the entry from orbit. The ground-based system will be capable of accurate state propagation for free-flight phases. Radio communication will be necessary in order for the ground and onboard capabilities to work as a coordinated system. The use of radio equipment for state determination is discussed for the ascent, orbit, rendezvous, descent, and abort phases of Shuttle missions.

Schiesser, E. R.↗
NASA NTRS1978

Forerunners - Outer rims of solar coronal transients

The large loop or blob-like transient events viewed in the white-light corona are rimmed by broad regions where the density is slightly enhanced above the pretransient corona. Every one of the Skylab events studied for which sufficiently good Skylab coronagraph coverage is available shows this effect. The upper boundaries of these 'forerunners' blend gradually into the background corona 1-2 solar radii above the transient's leading edges. In any single event, the coronal mass enhancement represented by the forerunner comprises up to 25% of the total excess mass present in the coronagraph's field of view and includes a much larger volume of the corona than previously attributed to the underlying transient. A forerunner without an accompanying transient has not yet been seen. Clearly, forerunners must be reckoned with in any proposed models of discrete outward coronal mass motions, because they indicate the presence of disturbed corona far ahead of the denser portions of the event.

Jackson, B. V.↗
NASA NTRS1978

Visions of the future operational meteorological satellite system

Visionary concepts of the operational environmental satellite system of the 1990's are presented. These exploit planned and anticipated advances in technology. The system comprises 8 Low Earth Orbitors (LEOS) at 500 km height for global coverage at 3 hourly intervals and 3 Geosynchronous Earth Orbitors (GEOS) for Western Hemisphere coverage with stereo capability and near simultaneous viewing of several regional areas. The LEOS emphasize passive and active microwave and Lidar sensing; the GEOS focus on high resolution visible and IR imaging and passive soundings. The GEOS also serve as data relays from the LEOS and as data collection platforms for hazard-related data. An integrated data management system ties the space fleet together and blends the data with that from all other observing systems to process and distribute the data and products to all users.

Atlas, D.↗
NASA NTRS1979

A partial oxidation staging concept for gas turbines using broadened specification fuels

A concept is described for using a very fuel-rich partial oxidation process as the first stage of a two-stage combustion system for onboard processing of broadened specification fuels to improve their combustion characteristics. Results of an initial step in the experimental verification of the concept are presented, where the basic benefits of H2 enrichment are shown to provide extended lean-combustion limits and permit simultaneous achievement of ultralow levels of NOx, CO, and HC emissions. The H2 required to obtain these results is within the range available from a partial oxidation precombustion stage. Operation of a catalytic partial oxidation reactor using a conventional aviation turbine fuel (JP5) and an unconventional fuel (blend of JP5/xylene) is shown to produce a 'fuel gas' stream with near-theoretical equilibrium H2 content. However, a number of design considerations indicate that the precombustion stage should be incorporated as a thermal reaction.

Clayton, R. M.↗
NASA NTRS1979

Interstellar abundances in the Zeta Ophiuchi clouds

The velocity component structure of UV interstellar absorption line profiles observed toward Zeta Ophiuchi clouds has been analyzed; column densities of Mg II, P II, Mn II and Fe II are found for the clouds at -14.4 km/sec (the principal component) and those at about -30 km/sec (a blend of two components). Little or no depletion is noted in the secondary component, suggesting that the grain mantles have been sputtered off, perhaps by a shock front, in this moderately high-velocity cloud. Residual depletion of calcium and titanium in the shocked cloud provides information on the nature of the grain surfaces. In the low-velocity cloud, the relative abundances of neutral atoms may indicate a differential depletion within the cloud.

Snow, T. P., Jr.↗
NASA NTRS1979

Spectroscopic observations of winds on Venus. I - Technique and data reduction

Methods of measurement and reduction of high-dispersion photographic spectra of Venus are presented. Preliminary results are consistent with slow direct or no rotation at the level sample, and disagree strongly with a 4-day retrograde rotation. A serious systematic error, which affects much published work, is due to blending of solar lines in the sky with those reflected from the planet. This always tends to produce a spurious retrograde 'rotation'. Only data obtained in a dark sky, or daytime observations from which the sky lines have been accurately subtracted, can be relied upon. All such data give low wind speeds.

Young, A. T.↗
NASA NTRS1979

Far ultraviolet photometry of intermediate brightness stars from Apollo-Soyuz

We present photoelectric photometry in the 1350-1600 A band of 52 stars of intermediate brightness, using data obtained in 1975 July with a grazing incidence telescope aboard the Apollo-Soyuz Test Project. Upper or lower limits on the brightness of 106 additional objects which were spatially blended with one or more companions were also obtained. The data sample consists of stars with V not greater than 7.5 and spectral types from O6 through A5. When corrected for interstellar extinction, the ultraviolet photometry on a two-color diagram agrees very well with the predictions of the revised blanketed model atmospheres by Kurucz. Attention is also drawn to an anomalously UV-bright object which is probably associated with HD 100493.

Crawford, R.↗
NASA NTRS1979

An investigation of the 1.9 A feature in solar-flare X-ray spectra

The 1.9 A feature, observed in the X-ray spectra of three solar flares with the Columbia University and Lockheed Palo Alto Research Laboratory spectrometers on the OSO 8 satellite, is shown to be due to a blend of 1s-2p transitions in a range of Fe ions. In the temperature range 9-16 x -10 to the 6th K, the feature has a mean wavelength of 1.900 + or - 0.009 A and is 0.04 A wider than a single line, indicating that the main contributors are Fe XIX-Fe XXII. Most of the emission originates from the dielectronic recombination process, and when inner-shell excitation is included together with normal collisional excitation, the observed intensity of the feature can be accounted for adequately. For these events, if the electron density is below approximately 10 to the 12th/cu cm, deviations from ionization equilibrium will be significant for ions more highly ionized than Fe XXI.

Parkinson, J. H.↗