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  • AERODYNAMICS  (471)
  • ASTRONOMY  (270)
  • Adaptation
  • 2020-2022
  • 1980-1984
  • 1975-1979  (743)
  • 1979  (743)
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Years
  • 2020-2022
  • 1980-1984
  • 1975-1979  (743)
Year
  • 1
    Publication Date: 2006-01-12
    Description: In a period of escalating development costs for new aircraft, there is growing interest in a renewed and coordinated icing research effort to achieve an updating or modernization of each aspect of the technological issues that are involved. This includes the data base, analysis methods, test techniques, and test facilities.
    Keywords: AERODYNAMICS
    Type: Aircraft Icing; p 1-16
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  • 2
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    In:  CASI
    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 215-240
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  • 3
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    In:  CASI
    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 165-180
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  • 4
    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 151-164
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  • 5
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    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: Sci. Res. with the Space Telescope; p 5-46
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  • 6
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    In:  CASI
    Publication Date: 2006-01-12
    Description: The problem of aircraft icing is reported as well as the type of aircraft affected, the pilots involved, and an identification of the areas where reduction in icing accidents are readily accomplished.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Res. Center Aircraft Icing; p 21-27
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  • 7
    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 241-262
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  • 8
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    Publication Date: 2006-01-16
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Sci. Res. with the Space Telescope; p 47-75
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  • 9
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    Publication Date: 2006-01-12
    Description: The ice capabilities of rotary wing aircraft are examined. Recommendations are given to improve the inadequacies of the weather forecasts pertaining to ice, and to adopt a low maintenance anti-ice system.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Res. Center Aircraft Icing; p 29-30
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  • 10
    Publication Date: 2006-01-12
    Description: Helicopter ice protection design criteria was developed and technological shortcoming in meeting helicopter mission requirements is that of helicopter rotor blade ice protection. Airframe components are protected using existing technology while the rotor blade protected using the cyclic electrothermal deicing concept.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Res. Center Aircraft Icing; p 39-65
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  • 11
    Publication Date: 2006-01-12
    Description: An overview of the present situation in the field of aircraft icing with respect to certification and operation of nontransport category airplanes is given. Problems of definition and inconsistencies are pointed out. Problems in the forecasting and measurement of icing intensities are discussed. The present regulatory environment is examined with respect to its applicability and appropriateness to nontransport airplanes.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Res. Center Aircraft Icing; p 31-38
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  • 12
    Publication Date: 2006-01-12
    Description: Three areas of interest are commented on: cloud physics, nowcasting, and instrumentation. A comparison is made of what was done 30 years ago to what might be done in light of developments in related areas of cloud physics, weather modification and instrumentation.
    Keywords: AERODYNAMICS
    Type: NASA. Lewis Res. Center Aircraft Icing; p 17-19
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  • 13
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 14
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 15
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 16
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 17
    Publication Date: 2011-08-17
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 84; July 197
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  • 18
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Optical Engineering; 18; May-June
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  • 19
    Publication Date: 2011-08-17
    Description: This note discusses a computer program being developed to study the flow field near opposing perpendicular fuel injectors in scramjets. The MacCormack time-split, finite difference relaxation technique was used to solve the full two-dimensional compressible Navier-Stokes equations along with energy and species equations. By using this technique, a program was developed to consider the turbulent nonreacting flow of hydrogen and air in a rectangular duct. A damping term, proportional to the second derivative of pressure and temperature, was used to produce a stable solution behind the hydrogen jet in the neighborhood of the recompression shock. A case using actual conditions encountered in current scramjet design was analyzed, with results agreeing qualitatively with experimental observations.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; May 1979
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  • 20
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 228
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  • 21
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: ESA Astron. Uses of the Space Telescope; p 27-31
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  • 22
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: ESA Astron. Uses of the Space Telescope; p 375-392
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  • 23
    Publication Date: 2011-08-17
    Description: An attempt is made to show that the outer portion of the velocity profile of hypersonic turbulent boundary layers can be transformed so that the constants determined by a best fit to the law of the wake are in reasonable agreement with the wake constant for incompressible boundary layers at the same Reynolds number. Both y transformations (where y is distance from the surface) and velocity transformations produce velocity profiles which, with the proper choice of wall shear stress to give shear velocity, can be reduced to the incompressible law of the wall.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; Aug. 197
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  • 24
    Publication Date: 2011-08-17
    Description: A method is developed for computing the modified Struve functions that occur in unsteady aerodynamics. The method uses a rational approximation supplemented by an asymptotic series for large argument. Simple recursive formulas for generating the coefficients are derived. The method is capable of generating results of arbitrary accuracy. It can also be used for complex argument and order. For greater computing speed, a method is presented that uses the rational and asymptotic approximations to generate Chebyshev coefficients.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 16; July 197
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  • 25
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 74; 3, Ma; May 1979
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  • 26
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Zeitschrift fuer angewandte Mathematik und Physik; 30; Mar. 25
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  • 27
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 91
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  • 28
    Publication Date: 2011-08-17
    Keywords: ASTRONOMY
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  • 29
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 20; Oct. 197
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  • 30
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 41; Nov. 197
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  • 31
    Publication Date: 2011-08-17
    Description: Numerical solutions are presented for the flow over a spherically blunted cone with massive surface blowing. Time-dependent viscous shock layer equations are used to describe the flowfield. The boundary conditions on the body surface include a prescribed blowing rate distribution. The governing equations are solved by a time-asymptotic finite-difference method. Results presented here are only for a perfect gas-type flow at zero angle of attack. Both laminar and turbulent flow solutions are obtained. It is found that the surface blowing smooths out the effect of the curvature discontinuity at the sphere-cone juncture point on the laminar flowfield and results in a negative pressure gradient over the body. The shock slope increases on the downstream portion of the body as the surface blowing rate is increased. The turbulent flow with surface blowing is found to redevelop a boundary-layer-like region near the surface. The effects of this boundary-layer-like region on the flowfield and heating rates are discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; Dec. 197
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  • 32
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society; vol. 189
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  • 33
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Vistas in Astronomy; 23; pt. 3
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  • 34
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 35
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 36
    Publication Date: 2011-08-17
    Description: 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.
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  • 37
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
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  • 38
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Icarus; 39; Aug. 197
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  • 39
    Publication Date: 2011-08-17
    Description: 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.
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  • 40
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 91
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  • 41
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 230
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  • 42
    Publication Date: 2011-08-17
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 228
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  • 43
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 90
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  • 44
    Publication Date: 2011-08-17
    Description: Implicit approximate factorization techniques (AF) are investigated for the solution of matrix equations resulting from finite-difference approximations to the full potential equation in conservation form. For transonic flows, an artificial viscosity, required to maintain stability in supersonic regions, is introduced by an upwind bias of the density. Two implicit AF procedures are presented, and their convergence performance is compared with that of the standard transonic solution procedure: successive line overrelaxation (SLOR). Subcritical and supercritical test cases are considered. Results indicate a substantial improvement in convergence rate for AF schemes relative to SLOR.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; Feb. 197
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  • 45
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 84; Jan. 197
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  • 46
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 227
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  • 47
    Publication Date: 2011-08-17
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 227
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  • 48
    Publication Date: 2011-08-17
    Description: Indicators used to determine the fully developed mean flow for two dimensional turbulent supersonic wakes are examined. The similarity variables for velocity temperature and the transverse coordinate used by Demetriades (1969) and Wagner (1972) are shown not to adequately distinguish transition from developed turbulent flows. The growth rate of the two dimensional turbulent wake as the wake develops from laminar to turbulent are shown to be low in the laminar region, increase at transition, and level off as fully developed turbulence is attained, demonstrating that wake growth rates are better indicators of a fully developed mean flow than are similarity variables.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; July 197
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  • 49
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 19; May 1979
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  • 50
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 76; 1, Ju; June 197
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  • 51
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 230
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  • 52
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    Publication Date: 2011-08-17
    Description: The instantaneous near field pressure fluctuations of an axisymmetric subsonic jet were measured by using a longitudinal and an azimuthal microphone arrays in order to qualitatively determine the behaviors of the quasi-periodic structure within the flow. Statistical analysis is used to explain the characteristic of the pressure signals. In addition to the information obtained by forming the power spectral density, auto- and cross-correlation functions, two types of signals are extracted through a conditional probability analysis to represent the quasi-periodic and the random fine structures within the turbulent jet. The quasi-periodic structure first appears as a rolling up of the mixing layer flow within one nozzle diameter downstream of the exit, then becomes fully developed at approximately 3 nozzle diameters downstream with a preferred Strouhal number range 0.3-0.4, and finally disappears beyond the end of potential core. This behavior is also reflected in the variation of the convection velocity.
    Keywords: AERODYNAMICS
    Type: Journal of Sound and Vibration; 64; May 8
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  • 53
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    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 84; Apr. 197
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  • 54
    Publication Date: 2011-08-17
    Description: Detailed experiments were conducted in a zero pressure gradient, supersonic turbulent boundary layer, including measurements of the three components of velocity fluctuations and the turbulent shear stress, for Reynolds numbers ranging from 11.7 million to 105 million at a freestream Mach number of 2.3. The mean flow measurements established the fully developed and equilibrium nature of the boundary layer. Measurements of the turbulence field show that the vertical and transverse fluctuations are essentially equal throughout the boundary layer at all Reynolds numbers, a feature that is different from observations in incompressible flows. The data show that the boundary layer exhibits similarity in the turbulence profiles for the entire Reynolds number range and agrees with previous compressible and incompressible data using Morkovin's scaling to account for compressibility effects.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 17; Apr. 197
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  • 55
    Publication Date: 2011-08-17
    Description: 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.
    Keywords: ASTRONOMY
    Type: Optical Society of America; vol. 69
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  • 56
    Publication Date: 2016-06-07
    Description: A large scale tunnel spanning wing was built and tested. The model can be operated as either a swept or unswept wing and can be tested in steady state or oscillated sinusoidally in pitch about its quarter chord. Data is taken at mid-span with an internal 6-component balance and is also obtained from miniature pressure transducers distributed near the center span region. A description is given of the system and a brief discussion of some of the steady and unsteady results obtained to date. These are the steady load behavior to Mach numbers of approximately 1.1 and unsteady loads, including drag, at a reduced frequency of approximately 0.1.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 445-458
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  • 57
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    Publication Date: 2016-06-07
    Description: The design and construction of a self streamlining wall test section for the Langley 0.3 meter transonic cryogenic tunnel was included in the fiscal year 1978 construction of facilities budget for Langley Research Center. The design is based on the research being carried out by M. J. Goodyer at the University of Southampton, Southampton, England, and is supported by Langley Research Center. This paper presents a brief description of the project. Included are some of the design considerations, anticipated operational envelope, and sketches showing the detail design concepts. Some details of the proposed operational mode, safety aspects, and preliminary schedule are presented.
    Keywords: AERODYNAMICS
    Type: Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 425-432
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  • 58
    Publication Date: 2016-06-07
    Description: The traditional procedure for estimating the performance of slotted walls for airfoil wind tunnels is reviewed, and a modification which improves the accuracy of this procedure is described. Unlike the traditional procedure, the modified procedure indicates that the design of airfoil wind-tunnel walls which induce minimal blockage and streamline-curvature effects is feasible. The design and testing of such a slotted wall is described. It is shown experimentally that the presence of a model can affect the plenum pressure and thus make the use of the plenum pressure as a calibration reference questionable. Finally, an ONERA experiment which shows the effect of the sidewall boundary layer on the measured model normal force is discussed.
    Keywords: AERODYNAMICS
    Type: Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 433-443
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  • 59
    Publication Date: 2016-06-07
    Description: A description is presented of a technique for the optimization of airfoil pressure distributions using an interactive inverse boundary-layer program. This program allows the user to determine quickly a near-optimum subsonic pressure distribution which meets his requirements for lift, drag, and pitching moment at the desired flow conditions. The method employs an inverse turbulent boundary-layer scheme for definition of the turbulent recovery portion of the pressure distribution. Two levels of pressure-distribution architecture are used - a simple roof top for preliminary studies and a more complex four-region architecture for a more refined design. A technique is employed to avoid the specification of pressure distributions which result in unrealistic airfoils, that is, those with negative thickness. The program allows rapid evaluation of a designed pressure distribution off-design in Reynolds number, transition location, and angle of attack, and will compute an airfoil contour for the designed pressure distribution using linear theory.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 383-397
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  • 60
    Publication Date: 2016-06-07
    Description: The current capabilities and the forthcoming plans for Langley's two-dimensional research facilities are described. The characteristics of the Langley facilities are discussed in terms of Reynolds number, Mach number, and angle-of-attack capabilities. Comments are made with regard to the approaches which have been investigated to alleviate typical problem areas such as wall boundary effects. Because of the need for increased Reynolds number capability at high subsonic speeds, a considerable portion of the paper deals with a description of the 20 by 60 cm two-dimensional test section of the Langley 0.3 meter transonic cryogenic tunnel which is currently in the calibration and shakedown phase.
    Keywords: AERODYNAMICS
    Type: Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 399-414
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  • 61
    Publication Date: 2016-06-07
    Description: A generalized boundary condition potential flow calculation method was combined with a momentum integral boundary layer method and a base flow theory of separation to predict airfoil viscous-inviscid interference up to and beyond stall. The resultant program considers laminar and turbulent separation and is, therefore, applicable to thin or thick airfoil stall. The calculated flow field includes the airfoil and the separation bubble recombination region behind the airfoil. Calculated pressure distributions and equivalent airfoil shapes, including the displacement thickness of the viscous regions, are compared with flow field measurements for several airfoils. The measured displacement thicknesses and wake centerlines corroborate the calculated shape. The comparison also suggests the use of the analytical solution to evaluate the measurements.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 335-345
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  • 62
    Publication Date: 2016-06-07
    Description: An application of numerical optimization to the design of advanced airfoils for transonic aircraft showed that low-drag sections can be developed for a given design Mach number without an accompanying drag increase at lower Mach numbers. This is achieved by imposing a constraint on the drag coefficient at an off-design Mach number while minimizing the drag coefficient at the design Mach number. This multiple design-point numerical optimization has been implemented with the use of airfoil shape functions which permit a wide range of attainable profiles during the optimization process. Analytical data for the starting airfoil shape, a single design-point optimized shape, and a double design-point optimized shape are presented. Experimental data obtained in the NASA Ames two-by two-foot wind tunnel are also presented and discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 315-325
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  • 63
    Publication Date: 2016-06-07
    Description: Research was conducted to provide a definite criterion for the prediction of the bubble burst on airfoils typical of those used for fighter wings. The approach taken was to correlate existing airfoil bubble burst data using various parameters at the laminar separation point. The method due to Weber was modified to provide a continuous analytic solution for the velocity distribution around the airfoil leading edge. Coupling the modified Weber method with the Stratford laminar separation prediction method leads to a universal chart giving the conditions at separation as a function of stagnation location and leading edge radius. Application of the combined method to available two-dimensional airfoil data resulted in an empirical criterion presenting the limiting local velocity gradient at separation as a function of the boundary layer momentum thickness at separation for bubble burst. The correlation leads as well to the qualitative explanation of two types of laminar stall: thin airfoil and leading edge. The validity of the correlation is demonstrated by predicting the lift coefficient and angle of attack for stall on airfoils with leading edge or trailing edge flaps.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 327-334
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  • 64
    Publication Date: 2016-06-07
    Description: Two theoretical methods are presented for optimizing multi-element airfoils to obtain maximum lift. The analyses assume that the shapes of the various high lift elements are fixed. The objective of the design procedures is then to determine the optimum location and/or deflection of the leading and trailing edge devices. The first analysis determines the optimum horizontal and vertical location and the deflection of a leading edge slat. The structure of the flow field is calculated by iteratively coupling potential flow and boundary layer analysis. This design procedure does not require that flow separation effects be modeled. The second analysis determines the slat and flap deflection required to maximize the lift of a three element airfoil. This approach requires that the effects of flow separation from one or more of the airfoil elements be taken into account. The theoretical results are in good agreement with results of a wind tunnel test used to corroborate the predicted optimum slat and flap positions.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt.1; p 237-253
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  • 65
    Publication Date: 2016-06-07
    Description: The coupling of the combined source vortex distribution of Green's potential flow function with contemporary numerical techniques is shown to provide accurate, efficient, and stable solutions to subsonic inviscid analysis and design problems for multi-element airfoils. The analysis problem is solved by direct calculation of the surface singularity distribution required to satisfy the flow tangency boundary condition. The design or inverse problem is solved by an iteration process. In this process, the geometry and the associated pressure distribution are iterated until the pressure distribution most nearly corresponding to the prescribed design distribution is obtained. Typically, five iteration cycles are required for convergence. A description of the analysis and design method is presented, along with supporting examples.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 221-236
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  • 66
    Publication Date: 2016-06-07
    Description: The Reynolds averaged Navier-Stokes equations are solved numerically for a variety of transonic airfoil configurations where viscous phenomena are important. Illustrative examples include flows past sensitive geometries, Reynolds number effects, and buffet phenomena.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 119-131
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  • 67
    Publication Date: 2016-06-07
    Description: The five basic elements of the two dimensional airfoil research program at Ames Research Center are illustrated. These elements are experimental, theoretical (including computational), validation, design optimization, and industry interaction. Each area is briefly discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 39-44
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  • 68
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    In:  CASI
    Publication Date: 2016-06-07
    Description: A low speed airfoil design and analysis program was developed which contains several unique features. In the design mode, the velocity distribution is not specified for one but many different angles of attack. Several iteration options are included which allow the trailing edge angle to be specified while other parameters are iterated. For airfoil analysis, a panel method is available which uses third-order panels having parabolic vorticity distributions. The flow condition is satisfied at the end points of the panels. Both sharp and blunt trailing edges can be analyzed. The integral boundary layer method with its laminar separation bubble analog, empirical transition criterion, and precise turbulent boundary layer equations compares very favorably with other methods, both integral and finite difference. Comparisons with experiment for several airfoils over a very wide Reynolds number range are discussed. Applications to high lift airfoil design are also demonstrated.
    Keywords: AERODYNAMICS
    Type: Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 73-100
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  • 69
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    In:  CASI
    Publication Date: 2016-06-07
    Description: An overview of past, present, and future airfoil research activities at the Langley Research Center is given. The immediate past and future occupy most of the discussion; however, past accomplishments and milestones going back to the early NACA years are dealt with in a broad-brush way to give a better perspective of current developments and programs. In addition to the historical perspective, a short description of the facilities which are now being used in the airfoil program is given. This is followed by a discussion of airfoil developments, advances in airfoil design and analysis tools (mostly those that have taken place over the past 5 or 6 years), and tunnel-wall-interference predictive methods and measurements. Future research requirements are treated.
    Keywords: AERODYNAMICS
    Type: Advanced Technol. Airfoil Res., Vol. 1, Pt. 1; p 11-38
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  • 70
    Publication Date: 2017-10-02
    Description: A method is presented for computing normal force and pitching moment coefficients for slender bodies of circular and noncircular cross section alone and with lifting surfaces. A semiempirical term representing viscous-separation crossflow is added to a term representing potential-theory crossflow. For bodies of revolution, computed aerodynamic characteristics agree with measured results for investigated free-stream Mach numbers from 0.6 to 2.9 and for angles of attack from 0 deg to 180 deg. For bodies of elliptic cross section, measured results are predicted well over the investigated Mach number range from 0.6 to 2.0 and the angle range from 0 deg to 60 deg. For all bodies the predictions are best at supersonic Mach numbers. For body-wing and body-wing-tail configurations, measured normal force coefficients and centers are predicted at the upper test Mach number of 2.0. As the Mach number is decreased to 0.6, the agreement for the normal-force coefficients rapidly deteriorates. When model flow-separation and vortex patterns are asymmetric, undesirable side forces are usually measured on the models at subsonic Mach numbers and zero sideslip angle. Generally, the side-force coefficients decrease or vanish with: increase in Mach number, decrease in nose fineness ratio, nose blunting, and flattening of body cross section.
    Keywords: AERODYNAMICS
    Type: AGARD High Angle of Attack Aerodyn.; 40 p
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  • 71
    Publication Date: 2017-10-02
    Description: Recent progress in a research program directed toward an improved vortex flow technology base was reviewed. Analysis methods for conical flow and analysis and design methods for nonconical flows are presented. Applications are made for a variety of planar, nonplanar, and interferring lifting surfaces. Several methods are shown to provide reasonable estimates of over-all forces and moments for simple wing planforms with the suction analogy method currently offering the most versatility for arbitrary configuration applications. For the prediction of surface loadings the free vortex sheet method being developed by Boeing is shown to have considerable promise and further development of this type of method is encouraged. A data base for ogee strake-wing configurations is summarized with an emphasis on the requirements for maximizing the interference lift. A strake planform design procedure is discussed and a first solution (gothic in planview) is integrated with a wing body. The data show the strake to exhibit expected stable vortex characteristics. It was found that, apart from increasing sweep, conically cambered delta wings developed drag levels approaching that of attached flow with increasing either the lift or the wing camber height, lastly, an approximate vortex flow design method, based on the suction analogy, is outlined and an example is given.
    Keywords: AERODYNAMICS
    Type: AGARD High Angle of Attack Aerodyn.; 31 p
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  • 72
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    In:  CASI
    Publication Date: 2016-06-07
    Description: The mechanism of fluid resistance within the limit of the square law is presented. It was concluded that the investigations should be extended and completed in two directions, namely: by an investigation of stable vortex configurations in space, and by considering the perfect fluid as the limiting case of a viscous fluid and then limiting the law of vortex of formation with the condition that only those fluid particles which were in contact with the surface of the body can receive rotation.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Classical Aerodyn. Theory; p 57-66
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  • 73
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 329-246
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  • 74
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 292-328
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  • 75
    Publication Date: 2016-06-07
    Description: Some aspects of ejector design and application, including, three dimensional effects and cross flow effects are presented.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 363-384
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  • 76
    Publication Date: 2016-06-07
    Description: Large scale structures in jets and in flows over cavities were investigated experimentally to determine their role in entrainment, mixing, and noise production. The presence of these structures resulted in growth of the shear layer and entrainment. Merging of adjacent large scale structures caused the near field pressure signal in excited flows. It is believed that both the entrained fluid as well as its eventual mixing with the jet flow can be controlled by introducing pulsation in the jet flow at a frequency for which the flow is most unstable.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 295-309
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  • 77
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 49-81
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  • 78
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 30-48
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  • 79
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 10-29
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  • 80
    Publication Date: 2016-06-07
    Description: Basic and applied studies in thrust augmentation conducted at the Aerospace Research Laboratory at Wright-Patterson AFB which led to an effective configuration of the jet flap diffuser ejector, are reviewed. A method for compressible ejector flow analysis, developed in support of the preliminary design of an ejector thrust aircraft, is discussed and applied to single- and two-stage ejectors.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 1-22
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  • 81
    Publication Date: 2016-06-07
    Description: The operational characteristics of sailwings are discussed with emphasis placed on the importance of the trailing edge cable tension. The three dimensional aerodynamic characteristics were obtained from wind tunnel tests, and the results compared to determine the magnitude of the aerodynamic penalties paid for various structural simplifications. For the sectional thickness ratios, it is concluded that, while the basic double-membraned sailwing has exceptional aerodynamic performance, even superior for some applications to the conventional hardwing, any notable deviation from this configuration results in an unacceptably large performance penalty.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center The Sci. and Technol. of Low Speed and Motorless Flight, Pt. 1; p 155-176
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  • 82
    Publication Date: 2016-06-07
    Description: The use of recently developed airfoil analysis/design computational tools to clarify, enrich and extend the existing experimental data base on low-speed, single element airfoils is demonstrated. A discussion of the problem of tailoring an airfoil for a specific application at its appropriate Reynolds number is presented. This problem is approached by use of inverse (or synthesis) techniques, wherein a desirable set of boundary layer characteristics, performance objectives, and constraints are specified, which then leads to derivation of a corresponding viscous flow pressure distribution. Examples are presented which demonstrate the synthesis approach, following presentation of some historical information and background data which motivate the basic synthesis process.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center The Sci. and Technol. of Low Speed and Motorless Flight, Pt. 1; p 1-31
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  • 83
    Publication Date: 2016-06-07
    Description: The beneficial aspects of an ejector powered V/STOL concept were reviewed. The feasibility of satisfactorily incorporating an ejector system in a high performance V/STOL aircraft was investigated. The external augmentor concept, based on the use of chordwise ejector slots, is presented. It is concluded that the external augmentor concept has a basic inherent simplicity and a sufficient augmentor performance potential to make feasible a high performance V/STOL aircraft based on ejectors.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 449-471
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  • 84
    Publication Date: 2016-06-07
    Description: A number of areas which have in the past contributed to weight, complexity, and thrust losses in the ejector-powered V/STOL vehicle were identified. Most of these interfaces taken singly do not represent a severe compromise to the vehicle; however, the bottom line is that the sum of compromises and the subsequent effects on performance, flight operations and maintenance have rendered the ejector V/STOL aircraft unattractive. In addition to some of the unique ejector/aircraft integration problems, the vehicle by virtue of having a V/STOL capability, is compromised in other areas. To be successful and acceptable, the advantages must outweight the disadvantages and simplicity with minimum penalties must be the rule. It is concluded that more emphasis must be placed on the ejector/aircraft interface for the concept to be successful.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 397-415
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  • 85
    Publication Date: 2016-06-07
    Description: The effectiveness of jet unsteadiness in enhancing flow entrainment was assessed. It was conducted that entrainment depends on the type and amount of jet unsteadiness. Apparently, the mere introduction of jet unsteadiness by small sinusoidal flow angle variations is insufficient to enhance entrainment but, it should be noted that the results were obtained at measuring stations which are all many nozzle widths downstream of the jet nozzle. Thus, no fully conclusive statement can be made at this time about the entrainment close to the nozzle. The high entrainment of the fluidically oscillated jet was caused by the high-frequency content of this square wave type of oscillation but more detailed measurements are clearly needed, in particular for the fluidically oscillated and the pulsed jets. Practical ejector application requires the proper trade-off between entrainment and primary nozzle thrust efficiency.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 311-324
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  • 86
    Publication Date: 2016-06-07
    Description: A small scale rectangular throat ejector with plane slot nozzles and a fixed throat area was tested to determine the effects of diffuser sidewall length, diffuser area ratio, and sidewall nozzle position on thrust and mass augmentation. The thrust augmentation ratio varied from approximately 0.9 to 1.1. Although the ejector did not have good thrust augmentation performance, the effects of the parameters studied are believed to indicate probable trends in thrust augmenting ejectors.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 239-251
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  • 87
    Publication Date: 2016-06-07
    Description: An exploratory investigation was performed in the Langley low-turbulence pressure tunnel to determine the effect of a plastic coating on the profile drage of a practical-metal-construction sailplaine airfoil. The mode was tested with three surface configurations: (1) filled, painted, and sanded smooth; (2) rough bare metal; and (3) plastic-coated. The investigation was conducted at Reynolds numbers based on airfoil chord of 1,100,000, 2,200,000, and 3,300,000 at a constant Mach number of 0.10. The results indicate that, at all three Reynolds numbers, the order of the drag values of the three surface configurations, starting with the highest drag, was: filled, painted, and sanded smooth; rough bare metal; and plastic-coated.
    Keywords: AERODYNAMICS
    Type: The Sci. and Technol. of Low Speed and Motorless Flight, Pt. 1; p 33-64
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  • 88
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 166-194
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  • 89
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 140-165
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  • 90
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 101-113
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  • 91
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 114-139
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  • 92
    facet.materialart.
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    In:  CASI
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 82-100
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  • 93
    Publication Date: 2016-06-07
    Description: A flexible, and easily modified, test rig is described which allows a one dimensional nonsteady flow stream to be generated, economically from a steady flow source of compressed air. This nonsteady flow is used as the primary stream in a nonsteady flow ejector constituting part of the test equipment. Standard piezo-electric pressure transducers etc. allow local pressures to be studied, as functions of time, in both the primary and secondary (mixed) flow portions of the apparatus. Provision is also made for measuring the primary and secondary mass flows and the thrust generated. Sample results obtained with the equipment are presented.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejector; p 325-349
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  • 94
    facet.materialart.
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Ejector augmenters in which the transfer of mechanical energy from the primary to the secondary flow takes place through the work of interface pressure forces are investigated. Nonsteady flow processes are analyzed from the standpoint of energy transfer efficiency and a comparison of a rotary jet augmenter to an ejector is presented.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 187-203
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  • 95
    Publication Date: 2016-06-07
    Description: The use of parametric flow analysis, rather than parametric scale testing, to support the design of an ejector system offers a number of potential advantages. The application of available 3-D flow analyses to the design ejectors can be subdivided into several key elements. These are numerics, turbulence modeling, data handling and display, and testing in support of analysis development. Experimental and predicted jet exhaust for the Boeing 727 aircraft are examined.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 55-70
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  • 96
    Publication Date: 2016-06-07
    Description: 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.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp; p 390-408
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  • 97
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    In:  CASI
    Publication Date: 2016-06-07
    Description: A technology assessment of extrasolar X-ray astronomy is presented. The role and significance of the Einstein Observatory is described.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center HEAO Sci. Symp.; p 262-291
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  • 98
    Publication Date: 2016-06-07
    Description: The XFV-12A, a unique V/STOL technology prototype aircraft being developed for the Navy, is described. The innovative design features a thrust augmented wing and a canard ejector. Structural, functional, and control test performances are discussed. Static tether test results are also discussed. Assessment of test results are given along with projections for future modification areas.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 473-480
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  • 99
    Publication Date: 2016-06-07
    Description: Advantages and problems associated with augmentation of reaction controls are discussed. The current status of compact ejector technology and the expected performance of known efficient designs for reaction control applications are presented.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center Workshop on Thrust Augmenting Ejectors; p 417-436
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  • 100
    Publication Date: 2016-06-07
    Description: A fluid mechanics review of chemical laser ejectors is presented. The characteristics of ejectors with single and multiple driver nozzles are discussed. Methods to compute an optimized performance map in which secondary Mach number and performance are computed versus mass ratio, to compute the flow distortion at each optimized condition, and to determine the thrust area for the design point to match diffuser impedence are examined.
    Keywords: AERODYNAMICS
    Type: NASA. Ames Res. Center. Workshop on Thrust Augmenting Ejectors; p 109-139
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