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  • Inorganic Chemistry  (5.498)
  • Analytical Chemistry and Spectroscopy  (3.254)
  • Chemical Engineering  (1.916)
  • Cell & Developmental Biology  (1.610)
  • AIRCRAFT PROPULSION AND POWER  (1.211)
  • ASTRONOMY  (1.188)
  • 1975-1979  (12.818)
  • 1915-1919
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  • 1
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    Aircraft Energy Efficiency (ACEE) status report (1979)
    In:  CASI
    Details
    Publikationsdatum: 2009-11-17
    Beschreibung: Fuel efficiency in aeronautics, for fuel conservation in general as well as for its effect on commercial aircraft operating economics is considered. Projects of the Aircraft Energy Efficiency Program related to propulsion are emphasized. These include: (1) engine component improvement, directed at performance improvement and engine diagnostics for prolonged service life; (2) energy efficient engine, directed at proving the technology base for the next generation of turbofan engines; and (3) advanced turboprop, directed at advancing the technology of turboprop powered aircraft to a point suitable for commercial airline service. Progress in these technology areas is reported.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 1-58
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  • 2
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    High-performance-vehicle technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Propulsion needs of high performance military aircraft are discussed. Inlet performance, nozzle performance and cooling, and afterburner performance are covered. It is concluded that nonaxisymmetric nozzles provide cleaner external lines and enhanced maneuverability, but the internal flows are more complex. Swirl afterburners show promise for enhanced performance in the high altitude, low Mach number region.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 445-462
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  • 3
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    Vertical Takeoff and Landing (VTOL) propulsion technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Propulsion problems and advanced technology requirements of VTOL aircraft are discussed. Specific topics covered include inlets with high angle of attack capability, rapid thrust modulation fans, and propulsion-system/aircraft-control integration.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 409-444
    Format: text
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  • 4
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    Hypersonic propulsion (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Research on hydrogen fueled scramjet engines for hypersonic flight is reviewed. Component developments, computational methods, and preliminary ground tests of subscale scramjet engine modules at Mach 4 and 7 are emphasized. Airframe integration, structures, and flow diagnostics are also discussed. It is shown that mixed-mode perpendicular and parallel fuel injection controls heat release over a wide Mach range and the fixed geometry inlet gives good performance over a wide range of Mach numbers.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 387-408
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  • 5
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    Control technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: An overview of engine control technology is presented with emphasis on gas turbine engine controls. The role of the government, and NASA in particular, in advancing this technology is discussed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 329-344
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  • 6
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    Supersonic propulsion technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Propulsion concepts for commercial supersonic transports are discussed. It is concluded that variable cycle engines, together with advanced supersonic inlets and low noise coannular nozzles, provide good operating performance for both supersonic and subsonic flight. In addition, they are reasonably quiet during takeoff and landing and have acceptable exhaust emissions.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 345-386
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  • 7
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    Mechanical components (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Research on bearings, gears, seals, and rotor dynamics (specifically high speed balancing and dampers) is presented. The research pertains to problems in both aircraft turbine engines and helicopter transmissions.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 273-308
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  • 8
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    Instrumentation technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Some of the efforts made in applying technologically new tools to today's propulsion measurement problems are described. They include: (1) a blade-tip clearance system; (2) a pulsed thermocouple system used to measure gas temperature with a thermocouple at temperatures above the melting point of the thermocouple; (3) an optical technique for measuring blade flutter; (4) a probe for dynamic flow and flow angle measurement; and (5) a laser anemometer system for rapidly mapping the flow profiles between the blades of a rotating compressor.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 309-328
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  • 9
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    Turbomachinery technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: A technology assessment of turbomachinery is presented. The design of the fan, compressor, and turbine components for future advanced aircraft engines is discussed. Basic flow characteristics in compressors and turbines and the heat transfer phenomena in cooled turbines are also discussed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 231-272
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  • 10
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    Computational fluid mechanics of internal flow (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Major solution techniques for internal computational fluid mechanics are discussed and some examples are presented. The major steps involved in developing a large computer code are then discussed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 187-230
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  • 11
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    Alternative jet aircraft fuels (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Potential changes in jet aircraft fuel specifications due to shifts in supply and quality of refinery feedstocks are discussed with emphasis on the effects these changes would have on the performance and durability of aircraft engines and fuel systems. Combustion characteristics, fuel thermal stability, and fuel pumpability at low temperature are among the factors considered. Combustor and fuel system technology needs for broad specification fuels are reviewed including prevention of fuel system fouling and fuel system technology for fuels with higher freezing points.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 129-148
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  • 12
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    Materials and structures technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: Materials and structures performance limitations, particularly for the hot section of the engine in which these limitations limit the life of components, are considered. Failure modes for components such as blades, vanes, and combustors and how they are affected by the environment for such components are discussed. Methods used to improve the materials used for such components are: (1) application of directional structures to turbine components for high strength at high temperatures; (2) improved coatings to increase oxidation and corrosion resistance; (3) increase strength and stiffness with reduced weight by applying higher specific properties of composite materials; and (4) cost effective processing such as near net shape powder methods applied to disks. Life prediction techniques developed to predict component life accurately in advance of service and progress in improving the intermediate and cold section components of turbine engines are covered.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 149-186
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  • 13
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    Noise reduction (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-07-16
    Beschreibung: The turbofan engine's noise-producing components are discussed in terms of efficient and economical noise reduction techniques that do not penalize the engine performance or weight significantly. Specific topics covered include fan noise, acoustic suppression, jet noise technology, combustor noise, and aircraft noise prediction.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 85-128
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  • 14
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    Emission reduction (1979)
    In:  CASI
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    Publikationsdatum: 2006-07-16
    Beschreibung: Control of the gaseous pollutant emissions of aircraft engines is considered in terms of the emission standards for six classes of aircraft engines. Emphasis is placed on combustor design concepts to significantly reduce emissions levels and lean-burning techniques to lower flame temperature, to reduce the oxides of nitrogen in the gaseous emissions.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Aeropropulsion 1979; p 59-84
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  • 15
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    Absorption lines in the spectra of distant objects (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: Studies that can be carried out with the Space Telescope of absorption line systems which may be expected to occur in the spectra of distant objects are discussed. The phenomenology of quasar absorption line systems is described and the principal suggested explanations are summarized. It is proposed that the numerous Ly-alpha systems are caused by 'extremely large hydrogenic halos around galaxies or clusters of galaxies. Two tests are also described for the origins of known absorption systems, the results of which will favor either the cosmological or intrinsic hypothesis. Absorption lines that are likely to be strongest are listed and a sample observing program is presented.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 215-240
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  • 16
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    Space telescope observations of normal galaxies (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: Observations of the stellar content of galaxies are discussed. Specific emphasis is placed on the following two types of observation: (1) those objects near enough to observe individual stars; and (2) those so distant that only their integrated light can be observed.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 165-180
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  • 17
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    Population statistics of faint stellar and non-stellar objects (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: A disc and halo population model is constructed to fit star counts and color data down to V approximately 23 at absolute value of b = 90 deg. This model is used to predict star counts and colors down to V approximately 30. Deviations from these extrapolated relationships provide constraints on the number of faint quasars and black dwarf stars. It is shown that extra-galactic globular clusters start contributing significantly to star counts at V approximately 25 and are more numerous than stars for V 31. Morphological studies of galaxies with approximately 0.5, were made with the space telescope. Significant constraints on theoretical models that describe the evolution of clusters of galaxies are provided.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 151-164
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  • 18
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    The space telescope observatory (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: A guide to the expected characteristics of the space telescope (ST) observatory is presented. The general objectives of the ST observatory are summarized. The plans for the development of the observatory are described with a brief history of the scientific activities; an account of the scope of the present program; a summary of the major responsibilities of the contractors; and a list of the project milestones are included. The performance characteristics of the observatory are provided including the imaging and stray light characteristics, pointing capability, and operational access. The expected performance characteristics of all six of the first generation science instruments are summarized. The mode of operations is described which includes a discussion of program options, guide star selection, methods of acquisition, and quick look data capabilities.
    Schlagwort(e): ASTRONOMY
    Materialart: Sci. Res. with the Space Telescope; p 5-46
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  • 19
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    Radio astronomers, X-ray astronomers and the space telescope (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: The use of the Space Telescope and the study of objects in the radio and X-ray wavebands, particularly extragalactic objects, are discussed. The scientific objectives of a number of projects which involve observations with the Space Telescope are described.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 241-262
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  • 20
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    Planetary astronomy with the space telescope (1979)
    In:  CASI
    Details
    Publikationsdatum: 2006-01-16
    Beschreibung: Experimental methods in planetary astronomy are discussed using a comparison of the advantages and disadvantages in the astronomical methods of ground based, Earth-orbit, and deep space missions. Problem areas in planetary astronomy which demonstrate the utility and power of the space telescope (ST) over other methods are delineated. These include utilizing the ST for studying the atmospheric dynamics, stratospheric and upper atmospheric processes, and circumplanetary nebulae of the planets. The capability of the ST for solar system observations is summarized with a discussion of the increases in resolution and sensitivity of the ST over other Earth-orbiting telescopes highlighted.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 47-75
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  • 21
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    Direct determination of asteroid diameters from occultation observations (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Of the available earth-based techniques for determining asteroid diameters, observation of stellar occultations involving asteroids is clearly the most direct. The high degree of accuracy achievable by this method has already been demonstrated in the case of Pallas, whose mean diameter has been measured with a standard error of plus or minus 2%. In this paper the problems, results and prospects of the stellar occultation technique are reviewed. It is shown that, with the use of a network of small, portable telescopes, the method is currently applicable to a large number of asteroids. The best results can be expected for asteroids of large angular diameter and regular shape. The potential of lunar occultation observations for asteroid diameter measurements is also briefly discussed.
    Schlagwort(e): ASTRONOMY
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  • 22
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    Proper elements and family memberships of the asteroids (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The proper elements tabulated are calculated according to the secular perturbation theory of Williams (1969); the free oscillations are referred to a zero value for the proper argument of perihelion. The secular theory for the planets is taken from Brouwer and van Woerkom (1950). Families with numbers smaller than 100 are reasonably close matches to families found by previous investigators. Families with numbers greater than 100 are new to this work. Guidelines for use of the table are given.
    Schlagwort(e): ASTRONOMY
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  • 23
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    Colorimetry and magnitudes of asteroids (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: In the present paper, 1500 UBV observations are analyzed by a new rather general multiple scattering theory which provided clear insight into previously poorly-recognized optical nature of asteroid surfaces. Thus, phase curves are shown to consist of a surface-texture controlled component, due to singly scattered light, and a component due to multiple scattering. Phase curve shapes can be characterized by a single parameter, the multiple scattering factor, Q. As Q increases, the relative importance of the opposition effect diminishes. Asteroid surfaces are particulate and strikingly similar to texture, being moderately porous and moderately rough on a scale greater than the wavelength of light. In concequence, Q (and also the phase coefficient) correlate well with geometric albedo, and there exists a purely photometric means of determining albedos and diameters.
    Schlagwort(e): ASTRONOMY
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  • 24
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    Families of minor planets (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Physical studies of individual family members show that at least the Themis, Eos, Koronis, Nysa/Hertha, and Budrosa families of minor planets are the result of the breakup of discrete parent bodies. Only a few families have been studied in detail, and even in those few cases, the full force of observational techniques has not been applied. Crucial for the understanding of families and their parent bodies are detailed physical studies of family members; precise mineralogical interpretation of observational data to identify the geochemistry of the parent bodies; and studies of the collisional evolution of family members.
    Schlagwort(e): ASTRONOMY
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  • 25
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    Minor planets and related objects. XXVIII - Asteroid magnitudes and phase relations (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal; 84; July 197
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  • 26
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    Space Telescope optics (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The paper reviews the optical technology that has been developed over the last decade for the Space Telescope. The optical design of the telescope, the optical performance control system, and the anticipated optical performance are all presented. Consideration is also given to the initial complement of focal plane instruments.
    Schlagwort(e): ASTRONOMY
    Materialart: Optical Engineering; 18; May-June
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  • 27
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    Forbidden Fe X and forbidden Fe XIV emission from Puppis A and other supernova remnants (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Measurements of Fe XIV 5303-A and Fe X 6374-A forbidden emission from several supernova remnants are reported, and their relation to X-ray observations is discussed. The brightest Fe XIV forbidden-emission region in Puppis A is interpreted as being the result of the supernova shock wave's interacting with a dense cloud in the interstellar medium.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 228
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  • 28
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    Status of the Space Telescope project in the United States (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: A general description of the evolution of the Large Space Telescope project is given, including mirror construction, interface requirements, and the review cycle for the scientific instruments. The anticipated participation of ESA scientists through the means of the Science Institute is discussed.
    Schlagwort(e): ASTRONOMY
    Materialart: ESA Astron. Uses of the Space Telescope; p 27-31
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  • 29
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    The Spacelab Wide Angle Telescope (SWAT) (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: A fast wide angle telescope that will be capable of imaging to the darker sky limit and in the ultraviolet wavelength region available above the atmosphere is described. The telescope (SWAT) has a resolution comparable to that of the large ground-based Schmidt telescope and a field of at least five degrees. A number of astrophysically important investigations can only be accomplished with such a telescope, e.g., detection of hidden, hot objects like hot white dwarfs and subwarfs in stellar binary systems, and energetic regions in globular clusters and galaxy nuclei. It permits unique studies of the UV-morphology of extended objects and allows discovery of very faint extensions, halos, jets, and filaments in galaxies. It can contribute to the investigation of dust in the Milky Way and in other galaxies and, with an objective prism, spectra of very faint objects can be obtained. The SWAT will localize objects for further study with the narrow-field Space Telescope.
    Schlagwort(e): ASTRONOMY
    Materialart: ESA Astron. Uses of the Space Telescope; p 375-392
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  • 30
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    Infrared photometry and spectrophotometry of G75.84+0.4 (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Photometric mapping of G75.84+0.4 at 12.6 microns is compared with previously published radio maps of the region to deduce the relative dust/gas mass ratio for the dust responsible for the 12.6-micron emission. Spectrophotometry from 2-4 microns and 8-13 microns of the highest-emission-measure region reveals the presence of the fine structure lines of forbidden Ar III at 8.99 microns, forbidden Ne II at 12.78 microns, and forbidden S IV at 10.53 microns. Estimates of the abundance of these ions are made, and the nature of the exciting source is discussed.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomy and Astrophysics; 74; 3, Ma; May 1979
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  • 31
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    Stability of inner planetary systems (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The stability of inner planetary systems with arbitrary mass ratios is studied on the basis of the model of the plane restricted three-body problem. A quantitative stability criterion is obtained in terms of the difference between the critical value of the Jacobi constants (at which bifurcation can occur) and the critical value corresponding to a planetary orbit. An orbit is stable if it cannot leave a region that contains only the larger central body (Hill). For small values of the mass parameter, the maximum dimensionless radius of a Hill-stable orbit is 1 minus 2.4 times the cube root of the mass parameter.
    Schlagwort(e): ASTRONOMY
    Materialart: Zeitschrift fuer angewandte Mathematik und Physik; 30; Mar. 25
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  • 32
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    Post-development image intensification by autoradiography (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: A method of post-development intensification of photographic images using a newly developed autoradiographic procedure is described. Radioactive Thiourea-S35 is combined with silver in the developed emulsion, which is then contact printed with a receiver emulsion. The beta decay from S35 produces an enhanced autoradiographic image. The laboratory technique is described and results of astronomical applications are presented.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 91
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  • 33
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    A comparison of luminosity calibrations for MK classifications of OB stars (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): ASTRONOMY
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  • 34
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    A general algorithm for the solution of Kepler's equation for elliptic orbits (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: An efficient algorithm is presented for the solution of Kepler's equation f(E)=E-M-e sin E=0, where e is the eccentricity, M the mean anomaly and E the eccentric anomaly. This algorithm is based on simple initial approximations that are cubics in M, and an iterative scheme that is a slight generalization of the Newton-Raphson method. Extensive testing of this algorithm has been performed on the UNIVAC 1108 computer. Solutions for 20,000 pairs of values of e and M show that for single precision, 42.0% of the cases require one iteration, 57.8% two and 0.2% three. For double precision one additional iteration is required.
    Schlagwort(e): ASTRONOMY
    Materialart: Celestial Mechanics; 20; Oct. 197
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  • 35
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    Airborne stellar spectrophotometry from 1.2 to 5.5 microns - Absolute calibration and spectra of stars earlier than M3 (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Airborne infrared spectrophotometry (1.2-5.5 microns, 1.5% resolution) is presented for 13 stars which have been extensively used as infrared calibration objects: alpha Lyr, alpha CMA, alpha UMi, beta Dra, and mu Her; the K giants beta Gem, alpha UMa, alpha Boo, gamma-1 And, and alpha Tau; and the M giants beta And, beta Peg, and alpha Cet. These spectra, obtained using NASA's Kuiper Airborne Observatory and Lear Jet Observatory, are virtually free of the interfering effects of terrestrial absorptions. Absolute calibration of the spectrophotometry was based on the theoretical model of alpha Lyr by Schild, Peterson, and Oke (1971), which fits photometric measurements at shorter wavelengths. The resulting flux densities are compared with previous ground-based photometry.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal Supplement Series; 41; Nov. 197
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  • 36
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    Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: This paper discusses effective temperatures, angular diameters, distances, and linear diameters that have been determined for 160 O and B stars on the basis of published UV spectrophotometry, visible and near-IR intermediate-band photometry, and model-atmosphere fluxes. The results are compared with previous measurements and calculations for main-sequence and giant O and B stars. It is found that: (1) the flux effective temperatures of O and B supergiants are systematically lower than those of main-sequence and giant stars of the same subtype; (2) the effective temperatures and radii of Beta Cep stars are the same as those of nonvariable stars of the same spectral type; (3) Be stars that do not have two Balmer jumps have effective temperatures very similar to those of normal B stars of the same subtype; (4) O and B stars increase in size from the main sequence to supergiants; and (5) late B supergiants are approximately twice as large as O9 supergiants.
    Schlagwort(e): ASTRONOMY
    Materialart: Royal Astronomical Society; vol. 189
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  • 37
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    Twenty southern peculiar emission-line stars (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Observational data for 20 southern stars having emission-line spectra that suggest a significant degree of mass ejection are given in order to present an atlas of their spectra and to give a quantitative description of their appearance during the 1961-62 epoch. Most of the stars are P Cygni stars; others include nova-like, peculiar Be, and symbiotic stars, as well as stellar planetary nebulae and emission-line binaries, all of whose spectra were obtained with the Newtonian two-prism Zeiss Spectrograph and the 74-inch reflector at Mount Stromlo Observatory. It is noted that among the P Cygni stars, there is a strong correlation between the a-e expansion velocity and the strength of Balmer emission, while in both the P Cygni and the Bep stars, there is positive dependence of Fe II and negative dependence of (Fe II) emission strengths on Balmer emission strength.
    Schlagwort(e): ASTRONOMY
    Materialart: Vistas in Astronomy; 23; pt. 3
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  • 38
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    Osculating orbital elements of the asteroids (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: In the present paper, osculating orbital elements are listed for 2118 numbered asteroids, of which 17 are considered lost. The columns give asteroid number; name; semimajor axis, in AU; eccentricity; longitude of the ascending mode; argument of perihelion; mean anomaly; and Julian date of epoch minus 2,400,000.
    Schlagwort(e): ASTRONOMY
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  • 39
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    Collisional evolution of asteroids - Populations, rotations, and velocities (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The collisional evolution of various initial populations of asteroids is simulated numerically and compared with the present asteroid size-frequency distribution to find those populations which collisionally relax to the present belt. Both orbital and size distributions are treated, as well as the simultaneous evolution of two collisionally interacting populations with different physical properties. If the initial belt distribution was a power law, the initial belt population at the time when the present high-collision speed was established was probably only modestly larger than the present population. However, other distributions allow a more massive early belt. The rotational evolution due to collisions of asteroids with power-law distributions is also examined and compared with observations, leading to conclusions generally in agreement with those of size evolution. The high-collision speed in the present belt is likely due to Jupiter. Gravitational stirring by massive Jupiter-scattered planetesimals or secular resonances sweeping through the belt are the most probable mechanisms.
    Schlagwort(e): ASTRONOMY
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  • 40
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    Earth-crossing asteroids - Orbital classes, collision rates with earth, and origin (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Asteroids that can intersect the orbit of the earth are discussed, which include Aten asteroids (semimajor axis (a) less than 1 AU, aphelion greater than 0.983 AU), Apollo asteroids (a greater than 1 AU, perihelion less than 1.017 AU), and Amor asteroids (perihelion distance between 1.017 and 1.3 AU). The principal sources of earth-crossing asteroids appear to be extinct comet nuclei and collision fragments from regions in the main asteroid belt. The total population of earth-crossers is estimated at 13,000, of which approximately 8% are Atens, 50% are Apollos, and 40% are Amors,and the present collision rate of such asteroids with the earth is estimated at about 3.5 objects, to absolute magnitude 18, per million years.
    Schlagwort(e): ASTRONOMY
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  • 41
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    QCSEE - The key to future short-haul air transport (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The paper describes the design and test procedure for the QCSEE (quiet, clean, short-haul experimental engine). The engines designed for the YC-14 and YC-15 STOL aircraft, both use a very low fan pressure ratio to keep jet-flap noise about 3 dB below total system noise. Other noise reducing features discussed are the low tip speed fans and a carefully selected number of fan blades and vanes with adequate spacing between them. Attention is also given to the development of a low emissions combustor, and reduction of fan frame weight, through the use of graphite/epoxy material. The YC-15 engine also employs variable pitch fans to provide thrust reversal, thus saving weight. Finally, it is noted that the tests have proven that the engines could be configurated to meet the needs of a powered lift system without excessively compromising performance or weight.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: ICAO Bulletin; 34; Apr. 197
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  • 42
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    M2 ocean tide parameters and the deceleration of the moon's mean longitude from satellite orbit data (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: An estimation is made of the principal long-period spherical harmonic parameters in the representation of the M2 ocean tide from the orbital histories of the three satellites 1967-92A, Starlette, and GEOS 3. The data used are primarily the evolution of the orbital inclinations of the satellites in conjunction with the longitude of the ascending node from GEOS 3. Analysis procedure and analytic formulation, as well as ocean tidal parameter estimation and deceleration of the lunar mean longitude are outlined. The credibility of the M2 ocean tide solution is further enhanced by the close accord between the computed value for the deceleration of the lunar mean longitude and other recently reported estimates. It is evident from the results presented that studies of close earth satellite orbits are able to provide important information about the tidal forces acting on the earth.
    Schlagwort(e): ASTRONOMY
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  • 43
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    Depletion of satellite atoms in a collisionless exosphere by radiation pressure (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Perturbations of hydrogen atoms in Keplerian orbits are examined by analyzing the rates of change of the classical orbital elements. There are three main effects: high inclination orbits with eccentricities e at least 0.4 are forced toward the ecliptic plane within a few weeks, the perigees of direct orbits drift rapidly toward stable positions roughly westward of the planet, and satellite orbits in or near such a stable point rapidly lower their perigees and the satellite's life is ended by a collision in the atmosphere. Thus there are effects tending to diminish the number of highly eccentric orbits with distant apogees in six principal directions. The various lifetimes are compared for a sample of initial elements.
    Schlagwort(e): ASTRONOMY
    Materialart: Icarus; 39; Aug. 197
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  • 44
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    Polarization and scattering characteristics in the atmospheres of earth, Venus, and Jupiter (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Our understanding of atmospheric scattering phenomena has increased through the combined developments of new electro-optical instrumentation, theoretical solutions for complex model atmospheres, and large computers enabling computation of such solutions. Earth satellites permit external, planetwide observations of our atmosphere, while spacecraft permit detailed measurements of the scattering by other planetary atmospheres. Some recent results are: elucidation of the effects of ozone absorption and high-altitude aerosol scattering on twilight colors and polarization; identification of a cloudbow on Venus and consequent deduction of the cloud particle shape, size distribution, and refractive index; and, the interpretation of Rayleigh scattering on Jupiter in terms of cloud-top topography.
    Schlagwort(e): ASTRONOMY
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  • 45
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    Absolute calibration in the 1750 A-3350 A region (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The absolute flux measurements in the rocket ultraviolet made by Bohlin, Frimout, and Lillie (BFL) are revised using a more correct treatment of the air extinction that enters the air calibration of their instrument. The absorption by molecular oxygen and ozone, Rayleigh scattering, and extinction by aerosols is tabulated for general use in ultraviolet calibrations performed in air. The revised absolute flux of Eta UMa and final fluxes for Alpha Lyr and Zeta Oph are presented in the 1750 A-3350 A region. The absolute flux of the star Eta UMa (B3 V) is compared to four other independent determinations in the 1200 A-3400 A region and a maximum difference of 35% is found near 1500 A between the OAO-2 and Apollo 17 fluxes. Longward of 1700 A the typical scatter in the different determinations is only plus or minus 5%. The rocket measurements of BFL, the ANS and TD-1 satellite data, and the Apollo 17 data are compared to the ultraviolet fluxes from the OAO-2, demonstrating a photometric reproducibility of about plus or minus 3%. Therefore, all four sets of spectrophotometry can be reduced to a common absolute scale.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 91
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  • 46
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    X-ray observations of H1908+050 /=SS 433/ (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The X-ray source H1908+050 (=4U 1908+05 = A1909+04) was observed for three 6 day periods in 1977 and 1978 with the HEAO A-2 experiment. Because of the positional error box and variability of the source, the unusual emission-line object and variable radio source SS 433 has been suggested as the optical counterpart. The X-ray luminosity of the source varied by a factor of about 2 on a time scale of 6 months, and the spectrum of the object is consistent with either a power law of photon index of 2.1 or with 14.3 KeV thermal bremsstrahlung emission with an about 575 eV equivalent-width iron line. These X-ray characteristics argue against the source being extragalactic, but do not uniquely identify the type of source. The measurements are consistent with emission from a white dwarf with 100 million gauss magnetic field, but are also similar to the X-ray emission sometimes seen from Cir X-1. A search has been made for X-ray emission from similar radio sources, but no new X-ray sources were detected. A previously known source, A1850+00, is a possible counterpart for one of these radio sources.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 230
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  • 47
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    High-resolution polarization structure of H-beta in Be shell stars measured with a new Digicon spectropolarimeter (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 228
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  • 48
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    Photographic observations of Theta-1 Orionis (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Photographic observations of the eclipsing binary Theta-1 Ori A suggest a secondary minimum near phase 0.64 of its 65.43233-day period. This minimum may be wavelength dependent. The star Theta-1 Ori E is suspected of being variable.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 90
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  • 49
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    Observations of secondary spectrophotometric standards in the wavelength range between 5840 and 10800 A (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Twenty-three stars that are suitable for use as secondary spectrophotometric standards are compared with Alpha Lyrae in the wavelength range between 5840 A and 1.1 microns. The consistency of the present data with previously existing measurements is discussed, along with the reliability of the present data. It is found that there is good agreement with previous data in some cases, but moderate or substantial discrepancies are exhibited in others. It is suggested that extinction variation is the most probable cause of the discrepancies, and observational procedures that may improve the situation with regard to the discrepancies are proposed.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal; 84; Jan. 197
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  • 50
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    X-ray spectra of X Persei (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: The GSFC cosmic X-ray spectroscopy experiment on OSO 8 observed X Per for 20 days during two observations in 1976 February and 1977 February. The spectrum of X Per varies in phase with its 13.9 minute period, hardening significantly at X-ray minimum. Unlike other X-ray binary pulsar spectra, those of X Per do not exhibit iron line emission or strong absorption features. Our data show no evidence for a 22 hour periodicity in the X-ray intensity of X Per. These results indicate that the X-ray emission from X Per may be originating from a neutron star in a low-density region far from the optically identified Be star.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 227
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  • 51
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    An observational study of the AFGL infrared sky survey. IV - Further results from the revised catalog (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 227
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  • 52
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    Analytical method for the effects of the asteroid belt on planetary orbits (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: Analytic expressions are derived for the perturbation of planetary orbits due to a thick constant-density asteroid belt. The derivations include extensions and adaptations of Plakhov's (1968) analytic expressions for the perturbations in five of the orbital elements for closed orbits around Saturn's rings. The equations of Plakhov are modified to include the effect of ring thickness, and additional equations are derived for the perturbations in the sixth orbital element, the mean anomaly. The gravitational potential and orbital perturbations are derived for the asteroid belt with and without thickness, and for a hoop approximation to the belt. The procedures are also applicable to Saturn's rings and the newly discovered rings of Uranus. The effects of the asteroid belt thickness on the gravitational potential coefficients and the orbital motions are demonstrated. Comparisons between the Mars orbital perturbations obtained by using the analytic expressions and those obtained by numerical integration are discussed. The effects of the asteroid belt on earth-based ranging to Mars are also demonstrated.
    Schlagwort(e): ASTRONOMY
    Materialart: Celestial Mechanics; 19; May 1979
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  • 53
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    Improved limits on intergalactic intracluster H I in the Coma Cluster (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: New observations using the Arecibo telescope have failed to detect intergalactic intracluster H I in the Coma Cluster. This represents a factor of two improvements over our previously reported limit (Wright et al., 1974) and makes it less likely that the cluster can be dynamically bound by H I. The highly flattened, rapidly rotating, extremely dense, cold H I clouds permitted by the observations will not evaporate over the cluster lifetime, but violate global stability criteria and hence cannot provide the missing mass in the cluster.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomy and Astrophysics; 76; 1, Ju; June 197
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  • 54
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    Soft X-ray spectrum and structure of the supernova remnant G65.2+5.7 (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: The HEAO 1 low energy detectors have observed the supernova remnant G65.2+5.7 in the energy range 0.2-2.5 keV. A strong, extended source of X-ray emission is observed coincident with the eastern side of the optical filamentary structure. The characteristic temperature of the emission is in the range 2-3.8 x 10 to the 6th K, and evidence is found for line emission at about 0.8 keV in the X-ray spectrum. These observations imply a shock velocity (425 km/s) and age (about 20,000 yr) that markedly disagree with the estimates from optical and radio observations.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 230
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  • 55
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    Isophotometry of the nuclei of M31 and M51 (1979)
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    Publikationsdatum: 2011-08-17
    Beschreibung: Isophotic contour maps derived from blue plates confirm the change in position angle as a function of distance from the center of M31 in the red region reported by Peterson, Ford, and Rubin (1977). The techniques used for M31 were then applied to a study of M51, for which similar results were obtained for the nuclear region. The spiral arms of M51 were traced for an additional half turn near the center of the galaxy.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal; 84; Apr. 197
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  • 56
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    Measurement of the size of the isoplanatic patch using a phase-correcting telescope (1979)
    In:  Other Sources
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    Publikationsdatum: 2011-08-17
    Beschreibung: In the presence of several-arc-second seeing at Mt. Wilson observatory, a flexible mirror image-sharpening telescope produced diffraction-limited (0.5 arcsec) images of the primary stars in the double star systems of Castor (alpha Gem), Algieba (gamma Leo) and Almach (gamma And). The images of both the primary and the companion star were simultaneously sharpened for Castor (separation 2 arcsec) and Algieba (4 arcsec) but not for Almach (10 arcsec). Thus the size of the isoplanatic patch came to lie between 4 and 10 arcsec. Using a simple model, we conclude that the bulk of the turbulent air responsible for the seeing was situated between 1.1 and 1.7 km above ground.
    Schlagwort(e): ASTRONOMY
    Materialart: Optical Society of America; vol. 69
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  • 57
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    Supersonic unstalled flutter (1979)
    In:  CASI
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    Publikationsdatum: 2017-10-02
    Beschreibung: A parametric study to show the effects of cascade geometry, inlet Mach number, and backpressure on the onset of single and multi degree of freedom unstalled supersonic flutter is presented. Several of the results are correlated against experimental qualitative observation to validate the models.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Stresses, Vibrations, Struct. Integration and Eng. Integrity (Including Aeroelasticity and Flutter); 14 p
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  • 58
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    Review of the AGARD S and M panel evaluation program of the NASA-Lewis SRP approach to high-temperature LCF life prediction (1979)
    In:  CASI
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    Publikationsdatum: 2017-10-02
    Beschreibung: The strain range partitioning SRP method method presented is a significant step forward in high temperature low cycle fatigue life prediction. Several concerns and recommendations regarding SRP were described. These dealt primarily with the problems associated with the application of SRP to cases involving small inelastic strains (and therefore long lives). The difficulties associated with partitioning these narrow hysteresis loops and the present inability of SRP to handle mean stress effects were also noted.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: AGARD Stresses, Vibrations, Struct. Integration and Eng. Integrity (Including Aeroelasticity and Flutter); 9 p
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  • 59
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    High resolution X-ray spectroscopy on the Einstein Observatory (1979)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: The X-ray spectroscope presented features both spectral and one dimensional spatial resolution. The capabilities of observing sources like supernova remnants, X-ray stars, and the halo surrounding galaxies are discussed.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 329-246
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  • 60
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    Nondispersive spectroscopy of celestial X-ray sources (1979)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: The spectroscope aboard the Einstein Observatory which utilizes nondispersive techniques is presented. Examples of kinds of thermal and nonthermal features that can be seen as well as the possibility of seeing small traces of thermal features in either much higher temperature objects or nonthermal objects are considered.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 292-328
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  • 61
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    The scientific results of the low energy portion of A-2 (1979)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Galactic phenomena observed using the HEAO 1 detectors are discussed. A source map of the soft X-ray sky is presented. Specific topics covered include the optical outburst of U Geminorum, low energy RS CVn stars, and the dwarf nova SS Cygni. Aspects of the SS Cygni pulsations are analyzed.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 49-81
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  • 62
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    Progress of the HEAO A-1 catalog (1979)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Results from the A-1 all sky survey are used to develop a catalog of X-ray sources. Various techniques used to identify and position the detected sources are discussed.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 30-48
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  • 63
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    X-ray variability observed with HEAO A-1 (1979)
    In:  CASI
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    Publikationsdatum: 2016-06-07
    Beschreibung: Results from the HEAO A-1 instrument which observed X-ray source variability over a wide range of accessible timescales are surveyed. The objects observed include quasars, BL Lacertae, and active galactic nuclei. A high sensitivity search for X-ray pulsars, known black hole candidates, period fluctuation in binary pulsars, and X-ray and gamma ray bursts are among the topics covered.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 10-29
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  • 64
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    Lean, premixed, prevaporized combustor conceptual design study (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Phase 1 of the Lean Premixed-Prevaporized Comubstor Design Study is a nine month analytical study effort with no experimental or testing activities included. The program has the objective to design and analyze advanced combustor concepts with features for fuel premixing and prevaporization upstream of the combustion zone for use in future subsonic aircrafts with features for fuel premixing and prevaporization upstream of the combustion zone for use in future subsonic aircraft engines. All of the designs also embody some form of variable geometry for combustor flow modulation. The primary criterion for these designs is low oxides of nitrogen emissions at stratospheric cruise conditions. Four combustor concepts are being designed for the NASA/GE Energy Efficient Engine (EEE) envelope and cycle. Current status of the program is that the four concepts sized for the EEE were designed and are currently undergoing analysis and evaluation.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 255-263
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  • 65
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    Autoignition of fuels (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: An autoignition test section and a premixing fuel injector developed to determine the autoignition characteristics of a variety of aircraft fuels are described. Parametric tests to map the ignition delay characteristics of Jet-A fuel were conducted at pressures of 10, 15, 20, 25, and 30 atm, inlet air temperatures up to 900K and fuel-air equivalence ratios of 0.3, 0.5, 0.7, and 1.0. Residence times in the range of 1 to 50 msec were obtained by interchanging spool pieces to create six different mixer/vaporizer lengths (6, 23, 53, 84, 99, and 130 cm) and by testing at two different airflow rates (0.5 and 1.0 kg/sec). The resulting free-stream velocities were in the range 20 to 100 m/sec. As expected, the results indicate that the ignition delay times decrease with increasing air temperature and pressure. Also, the data show that, for lean mixtures, ignition delay times decrease with increasing equivalence ratios.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 95-107
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  • 66
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    Modeling of premixing-prevaporizing fuel-air mixing passages (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The development of a computer program for the analytical prediction of the distribution of liquid and vapor fuel in the premixing-prevaporizing passage by the direct injection method is described. The technical approach adopted for this program is to separate the problem into three parts each with its own computer code. These three parts are: calculation of the two-dimensional or axisymmetric air flow; calculation of the three-dimensional fuel droplet evaporation; and calculation of the fuel vapor diffusion. This method of approach is justified because premixing passages operate at lean equivalence ratios. Hence, a weak interaction assumption can be made wherein the airflow can affect the fuel droplet behavior but the fuel droplet behavior does not affect the airflow.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 57-65
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  • 67
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    Fuel spray data with LDV (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Droplet size and two component velocities in the severe environment of an operating gas turbine combustor system can be measured simultaneously using the solar laser morphokinetomer (SLM) which incorporates the following capabilities: (1) measurement of a true two-dimensional velocity vector with a range of + or - (0.01-200 m/sec); (2) measurement of particle size (range 5 to 300 micron m) simultaneously with the measurement of velocity; (3) specification of probe volume position coordinates with a high degree of accuracy (+ or - 0.5 mm); (4) immediate on-line data checks; and (5) rapid computer storage of acquired data. The optical system of the SLM incorporates an ultrasonic beam splitter to allow the measurement of a two-dimensional velocity vector simultaneously with particle size. A microprocessor with a limited storage capability permits immediate analysis of test data in the test cell.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 47-55
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  • 68
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    Effect of swirl on premixed combustion (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Combustion in a premixed swirl combustor composed of confined concentric jets (5 cm and 10 cm diameter) were studied. The inner flow is fuel and air; the outer flow is air. Both flows may contain swirl either in the same or opposite directions. The combustor operates at one atmosphere without preheat; methane and propane were used as fuels. Related analyses and experiments were also performed for water flows and isotherm air flows. In these studies, a number of important concepts regarding premixing/prevaporized, swirl stabilized combustion were developed. Some of the more significant are discussed.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 203-213
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  • 69
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    Effect of degree of fuel vaporization on emissions for a premixed-prevaporized combustor system (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The impact of the degree of fuel vaporization upon emission from a flametube combustor was studied using an inlet air pressure of 3 x 10 to the 5th power pascals, inlet air temperatures of 600K and 700K, a reference velocity of 35 meters per second and equivalence ratios of .6 and .72 using Jet A fuel. Incoming air was preheated to temperatures from 600K to 700K by a nonvitiating preheater. Jet A fuel was injected into this airstream through two different fuel injectors manifolded together and mounted in series upstream of a watercooled preforated plate flameholder. The fuel-air mixture burned in a watercooled combustor section. Samples of the fuel-air mixture upstream of the flameholder were obtained for analysis to determine the local degree of fuel vaporization and the fuel-air ratio. Samples of the combustion products were analyzed to determine gaseous emissions. The effects of vaporization on carbon monoxide and nitric on carbon monoxide and nitric oxide emissions are presented.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Premixed Prevaporized Combustor Technol. Forum; p 127-130
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  • 70
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    A-4 scientific results (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Observations of galactic sources, extragalactic sources and gamma bursts with the A-4 instrument at energy 1 energies of between 0.1 to 10 MeV are discussed. Aximuthal scans are presented. The Crab Nebula and its spectrum and the spectrum of Cygnus Z-1 are described.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 166-194
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  • 71
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    High energy X-ray results from HEAO-1: X-ray pulsars, and the all sky survey (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Results of the sky survey performed with the high energy X-ray detectors of the A-4 experiment onboard the HEAO 1 spacecraft are presented. The data presented cover the energy range from 13 to 80 keV. Strong sources are identified by visual inspection and azimuthal superpositions are performed in order to find weak sources. Time variability is also examined. Results of studies of X-ray pulsars are given including a brief description of an X-ray pulsar in terms of current theory.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 140-165
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  • 72
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    A-3 scientific results (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The scanning modulation collimator experiment designed to identify the optical counterparts of celestial X-ray sources is described. Identification of galactic sources is discussed. Results concerning active galaxies are presented.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 101-113
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  • 73
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    A-3 scientific results - extragalactic (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The results of the HEAO A-3 experiment are summarized. Specific contributions of the experiment to extragalactic astronomy are emphasized. The discovery of relatively condensed X-ray emission in the cores of those clusters of galaxies which are dominated by a giant elliptical or cD galaxy, the discovery of extended X-ray emitting plasma in groups of galaxies, and the demonstration that BL Lac objects are a class of X-ray sources are among the topics discussed.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 114-139
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  • 74
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    HEAO A-2 extragalactic results (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Results from the HEAO A-2 experiment concerning the extragalactic X-ray sky are discussed. All-sky maps of hard X-ray sources detected are presented reflecting the temporal variability of the sources that make up the extragalactic X-ray sky. Most of the identified extragalactic objects are not clusters of galaxies but isolated galaxies. Spectra for sources representing classes of active galz galaxies, BL Lacertae objects, and N galaxies are discussed in order of luminosity.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 82-100
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  • 75
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    Einstein observations of active galaxies and quasars (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The radio galaxies Centaurus A and Signus B are discussed. In both these sources, a comparison of the radio and imaged X-ray flux is allowed for the measurement of the magnetic fields. Einstein observations of quasars are discussed. The number of known X-ray emitting QSO's was increased from 3 to 22 and the distances where these QSO's were seen to correspond to an age of 15 billion years. It was shown that these quasars contributed significantly to the X-ray background.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp; p 390-408
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  • 76
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    A high energy astronomy overview (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: A technology assessment of extrasolar X-ray astronomy is presented. The role and significance of the Einstein Observatory is described.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 262-291
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  • 77
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    Stabilization of premixed combustors (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: In order to attain a sufficiently good insight into the fluid mechanical processes taking place in combustors operating on premixed, prevaporized, and preheated gases, an experimental facility was developed where the flow field is tractable both experimentally and analytically. The configuration adopted for the initial stage of the study is based on the use of a step to stabilized the combustion zone. The primary purpose of the experimental apparatus is to provide a facility for studying the effects of the elementary fluid mechanical processes on the stability of a model combustion system in order to further the understanding of the intrinsic mechanism of nonsteady phenomena, rather than to provide criteria for unstable operation of combustors, as expressed by overall performance parameters, such as the blowout and flashback limits.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 187-202
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  • 78
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    Effects of flameholder blockage on emissions and performance of lean premixed-prevaporized combustors (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Results from a parametric study are presented. Tests were on conducted at inlet air pressure of 300,000 and 500,000 pascals, inlet air temperatures of 600K, 700K and 800K, reference velocites from 20 to 35 meters per second, and equivalent ratios from the lean stability limit to 0.7 using Jet A fuel. The tests were conducted in a closed duct test facility. Results from the test support the theory that flameholder blockage is one of the major determinants of the size and shape of the recirculation zone. The test data show that higher blockage with its larger recirculation zone provides more residence time which leads to more NOx formation.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Premixed Prevaporized Combustor Technol. Forum; p 157-162
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  • 79
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    Turbulence characteristics of compressor discharge flows (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Turbulence measurements were conducted in a large gas turbine engine (JT9D) at the entrance to the diffuser duct, joining the compressor discharge to the combustor inlet. Hot film probe and hot wire probe measurements were obtained at temperatures from 450K (350F) (idle) to 608K (635F) (rich approach). At I.D. (25 percent span) and mid-span locations, the turbulence intensity increased slightly from 6 + or - percent at idle condition to 7 or - 1 percent at rich approach. At O.D. (75 percent span) the turbulent intensity increased more rapidly, from 7.5 + or - 0.5 percent at idle to 15 + or - 0.5 percent at rich approach. The spectra showed turbulent energy distributed uniformly over a 0.1 to 5 KHz bandwidth (down 3db) at all operating conditions, corresponding to random turbulence with velocity wave lengths of 2 cm to 1 meter travelling at the mean velocity of 100 m/sec. Tests results are given in tables and graphs.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 5-31
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  • 80
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    Advanced low emissions catalytic combustor program at General Electric (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The Advanced Low Emissions Catalytic Combustors Program (ALECC) is being undertaken to evaluate the feasibility of employing catalytic combustion technology in aircraft gas turbine engines as a means to control emission of oxides of nitrogen during subsonic stratospheric cruise operation. The ALECC Program is being conducted in three phases. The first phase, which was completed in November, 1978, consisted of a design study to identify catalytic combustor designs having the greatest potential to meet the emissions and performance goals specified. The primary emissions goal of this program was to obtain cruise NO emissions of less than 1g/kg (compared with levels of 15 to 20 g/x obtained with current designs)/ However, good overall performance and feasibility for engine development were heavily weighted in the evaluation of combustor designs.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 215-227
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  • 81
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    Lean Stability augmentation study (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: An analytical and experimental program was conducted to investigate techniques and develop technology for improving the lean combustion limits of premixing, prevaporizing combustors applicable to gas turbine engine main burners. Three concepts for improving lean stability limits were selected for experimental evaluation among twelve approaches considered. Concepts were selected on the basis of the potential for improving stability limits and achieving emission goals, the technological risks associated with development of practical burners employing the concepts, and the penalties to airline direct operating costs resulting from decreased combustor performance, increased engine cost, increased maintenance cost and increased engine weight associated with implementation of the concepts. Tests of flameholders embodying the selected concepts were conducted.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 163-177
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  • 82
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    Emissions measurements for a lean premixed propane/air system at pressures up to 30 atmospheres (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: A series of experiments was conducted in which the emissions of a lean premixed system of propane and air were measured at pressures of 5, 10, 20 and 30 atm in a flametube apparatus. Measurements were made for inlet temperatures between 600K and 1000K and combustor residence times from 1.0 to 3.0 msec. A schematic of the test rig is presented along with graphs showing emissions measurements for nitric oxide, carbon monoxide, and UHC as functions of bustor residence time for various equivalence ratios, entrance temperatures and pressures; typical behavior of emissions as a function of equivalence ratio for a fixed residence time. Correlations of nitric oxide emission index with adiabatic flame temperature for a fixed residence time of 2 msec and pressures from 5 to 30 atm; and adiabatic flame temperature corresponding to CO breakpoint conditions for 2 msec residence time as a function of inlet temperature.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum p 109-125 Forum; p 109-125
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  • 83
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    Turbulence measurements in the compressor exit flow of a General Electric CF6-50 engine (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Ruggedized cooled film probes were used to measure CF6-50 compressor exit turbulence properties at three different engine idle condition test points. The turbulence probe was coupled to a constant temperature anemometer and signal conditioning system. An on-line readout system connected to the anemometer was used to check the data as it was acquired. At engine idle conditions, the turbulence intensity ranged from 4.8 percent to 5.6 percent and the length scale ranged from 5.64 cm to 6.95 cm. The length scale values are somewhat larger than the passage height at the measurement plane (5.54 cm), which indicates that the shape of the turbulent eddies are elongated in the axial direction. The microscale values range from about 0.73 cm to about 0.98 cm. Power spectral density distributions show that a large proportion of the turbulent energy at the measurement plane is concentrated at frequencies below one kilohertz.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 33-45
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  • 84
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    Lean, premixed, prevaporized combustor conceptual design study (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The seven month study program has the objective to identify and evaluate promising lean, premixed, prevaporized combustor concepts utilizing variable geometry and/or other flow control techniques. The general approach taken to accomplish this objective is outlined and consists of combustor design, design analysis and design ranking. The schedule being taken to achieve this program is shown. Although the ultimate goal of this program is the significant reduction of cruise oxides of nitrogen, both the EPA emission standards and combustor performance levels outlined are retained as goals as well.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 247-254
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  • 85
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    Advanced low emissions catalytic combustor program at Pratt and Whitney (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: The feasibility of employing catalytic combustion technology to control the emissions of oxides of nitrogen for subsonic, stratospheric cruise aircraft operations is the objective of this NASA contract. The existing Enivornmental Protection Agency standards for the landing and takeoff cycle were also required to be satisfied. Work for the first phase of a proposed three phase effort is reported and is concerned with analytical design studies.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 229-245
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  • 86
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    Effects of flameholder geometry on emissions and performance of lean premixed combustors (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Emission levels and performance of twelve flameholder designs were investigated in a lean, premixed propane-air system at inlet conditions of 800K and 10 atm. The flameholder tested represents six design concepts with two values of blockage for each concept. The design concept consists of the following geometries: perforated plate, wire grid, single cone, multiple cone, vee gutter and swirl cone. Measurements were made at reference velocities of 35 m/s, 25 m/s and 20 m/s at combustor stations 10 cm and 30 cm downstream of the flameholder.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Lewis Res. Center Premixed Prevaporized Combustor Technol. Forum; p 135-155
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  • 87
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    Effect of fuel/air nonuniformity on nitric oxide emissions (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: A flame tube combustor holding jet A fuel was used in experiments performed at a pressure of .3 Mpa and a reference velocity of 25 meters/second for three inlet air temperatures of 600, 700, and 800 K. The gas sample measurements were taken at locations 18 cm and 48 cm downstream of the perforated plate flameholder. Nonuniform fuel/air profiles were produced using a fuel injector by separately fueling the inner five fuel tubes and the outer ring of twelve fuel tubes. Six fuel/air profiles were produced for nominal overall equivalence ratios of .5 and .6. An example of three of three of these profiles and their resultant nitric oxide NOx emissions are presented. The uniform fuel/air profile cases produced uniform and relatively low profile levels. When the profiles were either center-peaked or edge-peaked, the overall mass-weighted nitric oxide levels increased.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Premixed Prevaporized Combustor Technol. Forum; p 131-134
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  • 88
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    Performance of a multiple venturi fuel-air preparation system (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: Spatial fuel-air distributions, degree of vaporization, and pressure drop were measured 16.5 cm downstream of the fuel injection plane of a multiple Venturi tube fuel injector. Tests were performed in a 12 cm tubular duct. Test conditions were: a pressure of 0.3 MPa, inlet air temperature from 400 to 800K, air velocities of 10 and 20 m/s, and fuel-air ratios of 0.010 and 0.020. The fuel was Diesel #2. Spatial fuel-air distributions were within + or - 20 percent of the mean at inlet air temperatures above 450K. At an inlet air temperature of 400K, the fuel-air distribution was measured when a 50 percent blockage plate was placed 9.2 cm upstream of the fuel injection plane to distort the inlet air velocity fuel injection plane to distort the inlet air velocity profile. Vaporization of the fuel was 50 percent complete at an inlet air temperature of 400K and the percentage increased linearly with temperature to complete vaporization at 600K. The pressure drop was 3 percent at the design point which was three times greater than the designed value and the single tube experiment value. No autoignition or flashback was observed at the conditions tested.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: Premixed Prevaporized Combustor Technol. Forum; p 85-93
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  • 89
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    Design of Propellers for Motorsoarers (1979)
    In:  CASI
    Details
    Publikationsdatum: 2016-06-07
    Beschreibung: A method was developed for the design of propellers of minimum induced loss matched to an arbitrary operating point characterized by disc loading (thrust or power), air density, shaft speed, flight speed, and number of blades. A consistent procedure is outlined to predict the performance of these propellers under off design conditions, or to predict the performance of propellers of general geometry. The examples discussed include a man powered airplane, a hang glider with a 7.5 kW (10 hp) 8,000 rpm engine, and an airplane-like motorsoarer.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA. Langley Res. Center The Sci. and Technol. of Low Speed and Motorless Flight, Pt. 1; p 285-303
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  • 90
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    Performance of light aircraft propellers, section 3 (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-28
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-165727
    Format: text
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  • 91
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    Unbekannt
    General Aviation Turbine Engine (GATE) study (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The feasibility of turbine engines for the smaller general aviation aircraft was investigated and a technology program for developing the necessary technology was identified. Major results included the definition of the 1988 general aviation market, the identification of turboprop and turboshaft engines that meet the requirements of the aircraft studies, a benefit analysis showing the superiority of gas turbine engines for portions of the market studied, and detailed plans for the development of the necessary technology.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-159482 , AIRESEARCH-21-2997
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 92
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    Static source locations for four nozzles mounted on a J-85 engine (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The test nozzles included a round 17.5 in. diameter variable flap ejector (VFE) nozzle, a round 'stovepipe' nozzle, and a 104 tube suppressor nozzle operated both with and without an ejector shroud. The velocities tested ranged from 600 to 1600 fps at an approximate total temperature of 1400 R. The axial position of the noise sources during static operation was determined by jet velocity, Strouhal number, and direction of propagation. The velocity dependence was more evident for the 104 tube suppressor nozzle than for the conical nozzles tested. The results for both the VFE conical nozzle and the stovepipe conical nozzle indicate source locations to be much closer to the jet exit plane than expected. Corrections for near field effects were found to differ slightly for each nozzle tested. The corrections presented are simply the differences between the measured near field levels and the required near field levels if spherical spreading is assumed from source to far field.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-152401
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 93
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    Low-cost directionally-solidified turbine blades, volume 2 (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: An endothermically heated technology was used to manufacture low cost, directionally solidified, uncooled nickel-alloy blades for the TFE731-3 turbofan engine. The MAR-M 247 and MER-M 100+Hf blades were finish processed through heat treatment, machining, and coating operations prior to 150 hour engine tests consisting of the following sequences: (1) 50 hours of simulated cruise cycling (high fatigue evaluation); (2) 50 hours at the maximum continuous power rating (stress rupture endurance (low cycle fatigue). None of the blades visually showed any detrimental effects from the test. This was verified by post test metallurgical evaluation. The specific fuel consumption was reduced by 2.4% with the uncooled blades.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-159562 , AIRESEARCH-21-2953-2-VOL-2
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
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    Space Telescope digicon technology (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The objective of this program was to develop the technology and construct a number of tubes conforming to the chosen configuration. A total of ten starts were made and ten tubes went through to test. Of the ten tubes three were CsI on LiF, six were CsTe on MgF2 and one was KNaCsSb on SiO2. All three faceplate crystals sealed successfully using indium as the sealant. In addition, a number of test seals were made and two photocathode sample runs were made. The tasks E-field, faceplate, anti-corona and electron optical analysis were actively pursued and the results integrated into the BASD HRS project.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA-CR-166704
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
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    Quiet Clean Short-haul Experimental Engine (QCSEE); acoustic performance of a 50.8-cm (20 inch) diameter variable pitch fan and inlet, test results and analysis, volume 1 (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: Tests were run both in forward and in reverse thrust modes with a bellmouth inlet, five accelerating inlets (one hard wall and four treated) with a design throat Mach number of 0.79 at the takeoff condition, and four low Mach inlets (one hard wall and three treated) with a design throat Mach number of 0.6 at the takeoff condition. Unsuppressed and suppressed inlet radiated noise levels were measured at conditions representative of QCSEE takeoff, approach, and reverse thrust operations. Measured aerodynamic performance of the accelerating inlet is also included. The test objectives, facility, configurations, are described as well as the data analysis, results, and comparisons.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-135117 , R77AEG229-VOL-1
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
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    TF34 engine compression system computer study (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The stability of the fan and the compressor components was examined individually using linearized and time dependent, one dimensional stability analysis techniques. The stability of the fan core integrated compression system was investigated using a two dimensional compression system model. The analytical equations on which this model was based satisfied the mass, axial momentum, radial momentum, and energy conservation equations for flow through a finite control volume. The results gave an accurate simulation of the flow through the compression system. The speed lines of the components were reproduced; the points of instability were accurately predicted; the locations where the instability was initiated in the fan and the core were indicated; and the variation of the bypass ratio during flow throttling was calculated. The validity of the analytical techniques was then established by comparing these results with test data and with results obtained from the steady state cycle deck.
    Schlagwort(e): AIRCRAFT PROPULSION AND POWER
    Materialart: NASA-CR-159889 , R78AEG612
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
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    HD 149499 B - The hottest white dwarf (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: IUE spectra of the white dwarf component of HD 149499, discovered from the Skylab experiments S-019 UV survey, show prominent lines of He II. The star appears to be helium-rich with He/H not less than 1. The ultraviolet fluxes show the temperature to be within the range 70,000-100,000 K, with the most probable value near 85,000 K.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 234
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
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    Comet Encke - Precession of the spin axis, nongravitational motion, and sublimation (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: From the observed light curve of P/Encke the jet force from sublimation is calculated both as a (precessing) torque and as a (perturbing) force transverse to the radius vector. An integral iteration is carried out over 59 perihelion passages, 1786-1977, to fit the previously determined nongravitational transverse force and to derive the precession of the spin axis. It is shown that the spin axis turned more than 100 degrees in longitude and almost 30 degrees in latitude from 1786 to 1977, but appears to have been almost fixed in direction for hundreds of revolutions before 1700. It is suggested that ejected meteoroidal debris accumulated on the currently less active hemisphere, insulating it to maintain a low activity level. A tentative rotation period of 6 h 33 min is derived, using Whipple's halo method. The suggested spinup rate is 21 min/century, while the current rate of relative mass loss by sublimation is 0.09% of the comet's mass per revolution. Moreover, the mass of the nucleus is estimated at less than 10 to the 16th grams, and its oblateness at less than 4%.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal; 84; Dec. 197
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
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    N-body experiments and missing mass in clusters of galaxies (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: It is commonly assumed that the distributions of surface density and radial-velocity dispersion in clusters of galaxies are sensitive tracers of the underlying distribution of any unseen mass. N-body experiments have been used to test this assumption. Calculations with equal-mass systems indicate that the effects of the underlying mass distribution cannot be detected by observations of the surface-density or radial-velocity distributions, and the existence of an extended binding mass in all well-studied clusters would be consistent with available observations.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 234
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
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    A high-resolution echelle spectrograph suitable for astronomical use at both far ultraviolet and visible wavelengths (1979)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-27
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 91
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
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