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  • Other Sources  (2,576)
  • AERODYNAMICS  (1,187)
  • ASTRONOMY  (888)
  • AIRCRAFT DESIGN, TESTING AND PERFORMANCE  (501)
  • 1980-1984  (2,576)
  • 1950-1954
  • 1925-1929
  • 1983  (900)
  • 1981  (921)
  • 1980  (755)
Collection
  • Other Sources  (2,576)
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  • 1980-1984  (2,576)
  • 1950-1954
  • 1925-1929
Year
  • 1
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    Curved-flow, rolling-flow, and oscillatory pure-yawing wind-tunnel test methods for determination of dynamic stability derivatives (1981)
    In:  CASI
    Details
    Publication Date: 2011-10-14
    Description: The test capabilities of the Stability Wind Tunnel of the Virginia Polytechnic Institute and State University are described, and calibrations for curved and rolling flow techniques are given. Oscillatory snaking tests to determine pure yawing derivatives are considered. Representative aerodynamic data obtained for a current fighter configuration using the curved and rolling flow techniques are presented. The application of dynamic derivatives obtained in such tests to the analysis of airplane motions in general, and to high angle of attack flight conditions in particular, is discussed.
    Keywords: AERODYNAMICS
    Type: AGARD Dyn. Stability Parameters; 13 p
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  • 2
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    EET theoretical design techniques (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: As a part of the EET aerodynamics program an out-of-house program was developed and monitored to provide theoretical procedures useful in the design of transport aircraft. The focus of the effort was to provide tools valid in the nonlinear transonic speed range. The effort was divided into two basic areas, inviscid configuration analysis and design procedures and viscous correction procedures.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Advan. Aerodyn.: Selected NASA Res.; p 79-94
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  • 3
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    F-111 TACT natural laminar flow glove flight results (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Improvements in cruise efficiency on the order of 15 to 40% are obtained by increasing the extent of laminar flow over lifting surfaces. Two methods of achieving laminar flow are being considered, natural laminar flow and laminar flow control. Natural laminar flow (NLF) relies primarily on airfoil shape while laminar flow control involves boundary layer suction or blowing with mechanical devices. The extent of natural laminar flow that could be achieved with consistency in a real flight environment at chord Reynolds numbers in the range of 30 x 10(6) power was evaluated. Nineteen flights were conducted on the F-111 TACT airplane having a NLF airfoil glove section. The section consists of a supercritical airfoil providing favorable pressure gradients over extensive portions of the upper and lower surfaces of the wing. Boundary layer measurements were obtained over a range of wing leading edge sweep angles at Mach numbers from 0.80 to 0.85. Data were obtained for natural transition and for a range of forced transition locations over the test airfoil.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Langley Research Center Advan. Aerodyn.: Selected NASA Res.; p 11-20
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  • 4
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    Spectroscopy in X-ray astronomy (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: Detailed features in cosmic X-ray sources and their associated temporal variation over a wide energy range were studied. Excess emission and absorption at approximately 6 to 7 kiloelectron volts in the spectra of supernova remnants, binary X-ray sources, and clusters of galaxies were observed. A gas scintillation proportional counter (GSPC) will be used as the detector system. In the gas scintillator the principal limitation is due to the statistics of the initial ionization process only.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 5
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    Far ultraviolet astronomy using the FAUST telescope (1981)
    In:  CASI
    Details
    Publication Date: 2006-06-04
    Description: The Far Ultraviolet Space Telescope (FAUST) a compact, wide field-of-view, far ultraviolet instrument designed for astronomical observations of extended and point sources is discussed. The design and application of the instrument are described. The prime objective is to observe faint astronomical sources with sensitivities higher than previously available. Scientific programs will include: (1) a search for ultraviolet stars which are predicted to exist at the stage of evolution prior to the final death of a star; (2) observations of galaxies and quasars; and (3) joint programs with other Spacelab 1 experiments. The secondary objective is to verify the suitability of the Spacelab as a platform for far ultraviolet astronomy: data will be provided on the ultraviolet background levels due to astronomical, terrestrial, and spacecraft generated sources; the levels of contaminants which affect ultraviolet instruments; and the capability of the Orbiter for stable pointing at celestial sources for useful periods of time.
    Keywords: ASTRONOMY
    Type: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 6
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    Effect of heavy rain on aircraft (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A summary on heavy rain effects on aircraft aerodynamics validation of research and some wind shear accidents in which heavy rain were an important factor. Frost formation and what frost does to the lift and drag curves for an airfoil was examined. If frost could cause severe aerodynamic problems for both general aviation and transport aircraft due to its roughness, then heavy rain produce a similar result. The influencing parameters of heavy rain on an aircraft are studied. Sources of aerodynamic roughness due to rain and wind shear and heavy rain accidents are outlined.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems 76-80 (SEE N82-21139 12-01)
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  • 7
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    Meteorology impact on future aircraft design (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Meteorology impact on future aircraft design is discussed. Upcoming changes in both design and operations that will be influenced by the meteorological environment are outlined. Future and more nonconventional designs and meteorological impact brought about by operational changes over the next few years are examined.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 29-34
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  • 8
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    Meteorological impact on aviation fuel efficiency (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The connection between fuel consumption and weather data is discussed. Fuel efficient flights creating adequate near real time weather information are examined. The lack of highly resolved real time and near real time wind and temperature data at flight altitudes is investigated. The existing systems, which is based on twice a day balloon observations, supplemented by pilot reports or other occasional data, is not adequate for optimum flight planning. The impacts of upper winds and temperatures on fuel efficiency and flight planning are not widely appreciated and developing new weather products are considered.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 15-19
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  • 9
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    An analytic solution to the classical two-body problem with drag (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The two body problem was analyzed with a specific drag model. The model treats drag as a force proportional to the vector velocity and inversely proportional to the distance to the center of attraction. The solution is expressed in terms of known functions and is of a simple and compact form. The time of flight is expressed as a quadrature in the true anomaly. The results are: (1) development of a vector differential equation which allows analysis of an infinite number of gravitational and drag models; and (2) obtaining the solution of a linear differential equation using the inverse method of laplace transforms.
    Keywords: AERODYNAMICS
    Type: Houston Univ. The 1981 NASA ASEE Summer Fac. Fellowship Program, Vol. 2; 22 p
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  • 10
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    Langley high-lift research on a high-aspect-ratio supercritical wing configuration (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: To determine the low speed performance characteristics of a representative high aspect ratio supercritical wing, two low speed jet transport models were fabricated. A 12-ft. span model was used for low Reynolds number tests in the Langley 4- by 7-Meter Tunnel and the second, a 7.5-ft. span model, was used for high Reynolds number tests in the Ames 12-foot Pressure Tunnel. A brief summary of the results of the tests of these two models is presented and comparisons are made between the data obtained on these two models and other similar models. Follow-on two and three dimensional research efforts related to the EET high-lift configurations are also presented and discussed.
    Keywords: AERODYNAMICS
    Type: Advan. Aerodyn.: Selected NASA Res.; p 55-77
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  • 11
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    Measured transonic unsteady pressures on an energy efficient transport wing with oscillating control surfaces (1981)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Highlight results are presented from subsonic and transonic pressure measurement studies conducted in the Langley Transonic Dynamics Tunnel on a supercritical wing model representative of an energy efficient transport design. Steady- and unsteady-pressure data were acquired on the upper and lower wing surface at an off-design Mach number of 0.60 and at the design Mach number of 0.78, for a Reynolds number of 2.2 x 10(6) (based on the wing average chord). The model configuration consisted of a sidewall-Mounted half-body fuselage and a semi-span wing with an aspect ratio of 10.76, a leading-edge sweepback angle of 28.8 degrees, and supercritical airfoil sections. The wing is instrumented with 252 static pressure orifices and 164 dynamic pressure gages. Model test variables included wing angle of attack, control-surface mean deflection angle, control-surface oscillating deflection angle and frequency, and phasing between oscillating leading-edge and trailing-edge controls when used together.
    Keywords: AERODYNAMICS
    Type: Advan. Aerodyn.: Selected NASA Res.; p 21-36
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  • 12
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    Viscous wing code development: A 3-D viscid-inviscid interactive analysis (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 607-63
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  • 13
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    Computation of separated flow on airfoils with the Grumfoil code (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 557-58
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  • 14
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    Analysis of airfoil transitional separation bubbles (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 539-55
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  • 15
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    Entropy effects and shock fitting in conical supersonic full potential flows (1983)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center, Theoretical Aerodynamics Contractors' Workshop, Volume 2; p 461-49
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  • 16
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    A study of altitude and flight path angle dynamics for a singularly perturbed fuel optimization problem (1983)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: This short paper will demonstrate that the separation of altitude and flight path angle dynamics using singular perturbation techniques for a transport fuel optimization problem results in an unacceptable oscillation in altitude. A technique for damping this oscillation by adding a penalty term to the cost function for the optimization problem will be discussed. This technique will be compared with a different approach that linearizes the altitude and flight path angle boundary layers.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 17
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    Detection of silicate emission features in the 8- to 13-micron spectra of main belt asteroids (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A presentation is given of 8.0-13.0 micron spectra (Delta lambda/lambda = 0.02-0.03) for six main belt asteroids, which range from 58 to 220 km in diameter and sample the five principal taxonomic classes (C, S, M, R and E). Narrow, well-defined silicate emission features are present on two of the asteroids, the C-type 19 Fortuna and the M-type 21 Lutetia. No comparable emission features are observed on the S-types 11 Parthenope and 14 Irene, the R-type 349 Dembowska or the E-type 64 Angelina.
    Keywords: ASTRONOMY
    Type: Icarus (ISSN 0019-1035); 56; 393-397
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  • 18
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    An exploratory study of area-efficient vortex flap concepts (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The potential of planform modification and hinge-line relocation to improve the thrust efficiency of vortex flaps was experimentally investigated on a 60-deg cropped delta wing model. Spanwise segmentation of the flap, together with chord-tailoring of the segments, allowed the vortex to be maintained on the outboard flap surfaces to higher angles of attack. In addition, location of the flap hinge aft of and underneath the wing leading edge generated substantial thrust from the vortex suction acting on the leading-edge lower surface. A combination of these beneficial effects allowed the flap/wing area to be reduced from 11.4 percent of the continuous flap to 6.3 percent of segmented flap, essentially without detriment to the incremental lift-to-drag ratio due to flap addition in the lift coefficient range 0.5-0.7 based on the basic wing area.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 1062-106
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  • 19
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    Observations and implications of natural laminar flow on practical airplane surfaces (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 20, p. 3138, Accession no. A82-40893
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft (ISSN 0021-8669); 20; 993-1006
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  • 20
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    The evolution of the infrared emission from the Type II supernova 1980k in NGC 6946 - The dust formation model (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper presents 1-4 micron photometry of supernova 1980 k in NGC 6946 obtained over a period of 1 year following the outburst. During the period between 1980 November 1 and December 19, the infrared emission probably originated from the extended atmosphere of the expanding star. The JHKL colors and a 1.3-2.6-micron spectrum observed during this period correspond to those of a blackbody with an average temperature of about 5000 K. Observations around 1981 May 31 showed that the supernova developed an infrared excess after 1980 December. This infrared excess persisted through 1981 October and is consistent with the appearance of thermal emission from about 700 to 900 K dust in addition to a hotter photosphere. The similarity of this behavior to that of the infrared evolution of some novae suggests that dust formation may be occurring in the supernova ejecta. The hypothesis, that the emission arises from preexisting grains in a circumstellar shell which are heated by the supernova outburst, is also consistent with the data.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal, Part 1 (ISSN 0004-637X); 274; 168-174
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  • 21
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    Stability of shock waves attached to wedges and cones (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 06, p. 799, Accession no. A82-17876
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1611-161
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  • 22
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    Ultraviolet and optical studies of binaries with luminous cool primaries and hot companions. III - Reticon radial velocities (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Radial velocities for 72 stars, most of them known or suspected binaries with F - K giant-supergiant primaries, are derived from Reticon spectra in the region 6005-6235 A at a scale of 7 km/s per diode. Cross-correlation of the spectra normally produces results accurate to better than 1.0 km/s. Eight new radial velocity variables are found (HR 2786, R Pup, HR 3291, HR 4451, HD 114520, HR 5667, HR 7014, and Nu1 Sgr). Improved orbits are determined for 15 known spectroscopic binaries, and provisional orbits are obtained for seven new spectroscopic binaries.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series (ISSN 0067-0049); 53; 553-571
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  • 23
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    Infrared observations of RS CVn stars (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The paper presents infrared photometry of the RS CVn binary stars AR Lac (1.2-10 microns) and MM Her (1.2-3.5 microns) as they egressed from their primary and secondary eclipses; of the eclipsing systems RS CVn and Z Her at maximum light (1.2-10 microns) and of the non-eclipsing systems UX Ari and HR 1099 (1.2-10 microns). An analysis of these and published V data based on flux ratio diagrams (linear analogues of color-color diagrams) shows that G and K stars supply the infrared light of these systems. In AR Lac, the combined light of a G5-K0 subgiant and either a late F dwarf or an early F subgiant can account for the observed visual and infrared light curves. None of these systems shows infrared emission from circumstellar matter. This result is simply understood: dust grains would not be expected to form in the physical conditions surrounding the subgiant, and the corona and chromosphere (whose properties have been deduced from spectroscopic X-ray observations) should not produce appreciable infrared emission.
    Keywords: ASTRONOMY
    Type: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 205; 859-873
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  • 24
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    Ultraviolet high-resolution spectroscopy from the Space Telescope (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The High Resolution Spectrograph is one of five scientific instruments which will be part of the Space Telescope observatory. The spectrograph was designed to take advantage of the imaging and pointing capabilities of the telescope to obtain ultraviolet spectra with spectral resolution comparable to large, ground-based coudeinstruments. Some of the results of the ground-based testing program will be described, along with applications of these properties to future science programs.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific, Publications (ISSN 0004-6280); 95; 543-549
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  • 25
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    On the determination of airplane model structure form flight data (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A procedure based on a modified stepwise regression and several selection criteria is presented for the determination of airplane model structure from flight data. The aerodynamic force and moment coefficients in an airplane model are expresed either as polynomials in output and input variables or as a combination of splines. The procedure is demonstrated in three examples by attempting to determine a local, extended and global model. Some of the resulting models are verified by using the maximum likelihood estimation or by examining model prediction capabilities.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 26
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    Theoretical studies of the effects of grain noise on photographic stellar astrometry and photometry (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A method of incorporating the effects of photographic emulsion grain noise into digital image centering algorithms is presented which improves the accuracy of the derived stellar positions and magnitudes. Theoretical formulae are then derived for the limiting error of the center, and the photometric parameters. For IIIa-J, this error is 0.2-0.3 mu for bright unsaturated images, which agrees quite well with measurements made with the Yale PDS microdensitometer. It is expected that, with further improvements in the positional accuracy of the PDS, it should be possible to reach the emulsion grain noise limit, providing that emulsion shifts or other large scale errors do not dominate. It is also shown that, with appropriate trimming, marginal distribution image centering algorithms can yield an accuracy only slightly poorer than that obtained with two-dimensional distributions.
    Keywords: ASTRONOMY
    Type: Astronomical Journal (ISSN 0004-6256); 88; 1683-168
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  • 27
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    A chimera grid scheme (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A mesh system composed of multiple overset body-conforming grids is described for adapting finite-difference procedures to complex aircraft configurations. In this so-called 'chimera mesh,' a major grid is generated about a main component of the configuration and overset minor grids are used to resolve all other features. Methods for connecting overset multiple grids and modifications of flow-simulation algorithms are discussed. Computational tests in two dimensions indicate that the use of multiple overset grids can simplify the task of grid generation without an adverse effect on flow-field algorithms and computer code complexity.
    Keywords: AERODYNAMICS
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  • 28
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    Conservative full-potential calculations for axisymmetric, transonic flow (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Previously cited in issue 17, p. 2873, Accession no. A81-38082
    Keywords: AERODYNAMICS
    Type: AIAA Journal (ISSN 0001-1452); 21; 1492-149
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  • 29
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    An improved celestial radio reference frame: JPL 1982-4 (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In the development of a celestial radio reference frame, there are now over 100 sources whose relative positions are known with an average uncertainty less than 5 milliarcseconds. These sources are fairly uniformly distributed over the celestial sphere north of -40 deg declination. Their positions are expressed in the new IAU system. This presentation describes the analysis involved in obtaining these results, as well as future plans for linking this system to the JPL planetary ephemerides.
    Keywords: ASTRONOMY
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  • 30
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    AFTI/F-16 flight test results and lessons (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The AFTI/F-16 flight test program is summarized, and several design issues of general interest are addressed. A brief description is given of the test vehicle, its flight control modes, and the flight envelopes in which testing was performed. Flight test results are summarized by addressing benefits experienced in flight control task-tailoring, handling qualities in mission tasks, aircraft structure considerations, digital flight control system performance, and human factors. Finally, several design issues relevant to future fighter aircraft are examined, including degraded flight control, system complexity, simplex information in redundant systems, and single failure propagation in redundant systems.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 31
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    Comets (1981)
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    Publication Date: 2011-08-18
    Description: The nature and origin of comets is discussed. Observations of the principal parts of comets, the dust and plasma tails, the hydrogen cloud, the coma and the cometary nucleus, are presented, and the icy conglomerate model of Whipple as extended by Delsemme accounting for the observed properties and their variation with heliocentric distance is examined. The origin of comets is considered in relation to the orbital statistics of the long-period comets and the existence of the Oort cloud on the edge of the solar system, and possible roles for comets in the solar nebula and the evolution of the solar system are indicated. Particular attention is then given to the discovery and properties of Halley's Comet, which is expected to reach perihelion in 1986, and to possible flyby and rendezvous missions to Halley's Comet and others.
    Keywords: ASTRONOMY
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  • 32
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    Electron densities for 10 planetary nebulae derived from the semiforbidden C III lambda 1907/1909 ratio. II (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Electron densities for IC 351, IC 2165, J900, IC 3568, NGC 6644, NGC 6891, IC 4997, NGC 7009, Hu 1-2, and IC 5217 are derived from high-dispersion semiforbidden C III spectrograms. For seven of these nebulae, the derived electron density is larger than the values derived from either surface brightness measurements or forbidden line ratios. Only one object, Hu 1-2, shows pronounced splitting of the semiforbidden C III emission lines due to a large expansion velocity.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 33
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    Medium energy gamma ray astronomy with transpacific balloon flights (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: Transpacific balloon flights with the University of California, Riverside (UCR) double scatter telescope are discussed. With flight durations from 5 days up to perhaps 15 days the long observation times necessary for medium energy (1-30 MeV) gamma ray astronomy can be obtained. These flights would be made under the auspices of the Joint U.S.-Japan Balloon Flight Program at NASA. It is proposed that flights can provide at least 30 hours of observation time per flight for many discrete source candidates and 120 hours for detecting low intensity cosmic gamma ray bursts.
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  • 34
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    Studies in astronomical time series analysis. I - Modeling random processes in the time domain (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Several random process models in the time domain are defined and discussed. Attention is given to the moving average model, the autoregressive model, and relationships between and combinations of these models. Consideration is then given to methods for investigating pulse structure, procedures of model construction, computational methods, and numerical experiments. A FORTRAN algorithm of time series analysis has been developed which is relatively stable numerically. Results of test cases are given to study the effect of adding noise and of different distributions for the pulse amplitudes. A preliminary analysis of the light curve of the quasar 3C 272 is considered as an example.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal Supplement Series; 45; Jan. 198
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  • 35
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    Three new 'nonterrestrial' molecules (1981)
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    Publication Date: 2011-08-18
    Description: Eight new interstellar lines have been detected from three molecules not previously observed spectroscopically in space or in the laboratory. One is a linear or nearly linear molecule with microwave constants B0 equals 21,337.15 plus or minus 0.06 MHz, D0 equals 21.4 plus or minus 1.5 kHz. This is the thioformyl ion HCS(plus), first identified because B0 and D0 are close to those calculated, and now confirmed by laboratory detection of one of the present lines (Gudeman et al.). The second molecule, also linear or nearly so, has microwave constants B0 equals 10,691,406 plus or minus 0.043 MHz, D0 equals 1.84 plus or minus 0.91 kHz close to those expected for the isoelectronic systems HOCO(plus) and HOCN; a choice between the two cannot be made on the basis of the available astronomical data. The existence of a third molecule is deduced from an unidentified line at 85,338 MHz that has been found in many sources, is fairly intense in several, and may be self-absorbed in Sgr B2.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 36
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    Discovery of phase-locked variable polarization in an RS Canum Venaticorum-like star, HR 5110 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Using measurements on 79 nights in 1980 January-August, it is established that the polarization in the ultraviolet (U band) varies synchronously on the known binary period of 2.6132 days, with a peak-to-peak amplitude of 0.03%. The pattern is mainly second harmonic in character, as typical of binary star examples such as Algol and Upsilon Her. Reflection by the cooler star, by a plasma concentration, or both, is suggested. The scale of the polarization seems to be consistent with Rayleigh scattering by neutral hydrogen on the cooler star, and a roughly lambda to the -4th wavelength dependence should be searched for. The QU curve suggests a sizeable inclination for the system, of about 45 deg, but this is preliminary. Separately, a possible weak periodicity might be present on a subsidiary period, conceivably related to a rotating star spot.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 37
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    Vortex-flow aerodynamics - An emerging design capability (1981)
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    Publication Date: 2011-08-18
    Description: Promising current theoretical and simulational developments in the field of leading edge vortex-generating delta, arrow ogival wings are reported, along with the history of theory and experiment leading to them. The effects of wing slenderness, leading edge nose radius, Mach number and incidence variations, and planform on the onset of vortex generation and redistribution of aerodynamic loads are considered. The range of design possibilities in this field are consequential for the future development of strategic aircraft, supersonic transports and commercial cargo aircraft which will possess low-speed, high-lift capability by virtue of leading edge vortex generation and control without recourse to heavy and expensive leading edge high-lift devices and compound airfoils. Attention is given to interactive graphics simulation devices recently developed.
    Keywords: AERODYNAMICS
    Type: Astronautics and Aeronautics; 19; May 1981
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  • 38
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    The 45 micron H2O ice band in the Kleinmann-Low Nebula (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 39
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    Use of multiblade sensors for on-line rotor tip-path plane estimation (1980)
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    Publication Date: 2011-08-18
    Description: Techniques are investigated for on-line estimation of rotor states in the nonrotating frame from multiple, simultaneous measurements in the rotating frame. The multiblade coordinate transformation is first applied to transform both flapping and flapping rate measurements into the nonrotating frame. The 'observer' approach is then used to generate algorithms for estimating tip-path plane rate and attitude from transformed flapping and flapping rate measurements. A numerical evaluation using simulated measurements is conducted to evaluate the performance of the algorithms and recommendations are made.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: American Helicopter Society; vol. 25
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  • 40
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    Longitudinal grooves for bluff body drag reduction (1981)
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    Publication Date: 2011-08-18
    Description: Wind tunnel test results are presented for four axisymmetric bluff body configurations in order to determine their effect on form and pressure drag. It was found that drag reductions on the order of 40% are obtainable with an afterbody incorporating four longitudinal 'V' grooves. Although this effect may be due to the functioning of the grooves as longitudinal, continuous vortex generators, it is concluded that further research is needed to elucidate the physical basis of the test results. Optimization of the effect will be useful in base drag reduction for such vehicles as automobiles and cargo aircraft with sharply upswept afterbodies.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 19; Apr. 198
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  • 41
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    Concerning the Wolf-Rayet and other luminous early-type stars (1981)
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    Publication Date: 2011-08-18
    Description: Effective temperatures, radii, and luminosities were determined from S2/68, ANS, UBV, and uvby photometry for four B0/B1 supergiants, four O4 stars, and four WN7/WN8 stars as well as for four test stars having spectral types between B1.5 V and 09 V and five stars with known angular diameters and effective temperatures. The effective temperatures of B1 Ia+ stars are found to be near 17,000 K, those of O4 stars near 45,000, and those of WN7/WN8 stars near 26,000 K. The question of modeling the atmospheres of hot luminous stars is examined, and it is noted that the photosphere can be modeled adequately using a classical plane-parallel layer model atmosphere. In addition, it is found that the Wolf-Rayet stars of types WN7/WN8 fall in the H-R diagram near the B0 Ia stars, while the others fall near B0.5 III stars. The evolutionary relationship between the Wolf-Rayet and O stars is considered; it is suggested that a Wolf-Rayet spectrum is a short-lived phase in the life of a massive star.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 42
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    Observation of the core of the Perseus cluster with the Einstein solid state spectrometer - Cooling gas and elemental abundances (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Solid State Spectrometer observations of the core of the Perseus cluster have resulted in the detection of X-ray emission lines due to Si, S, and Fe. Analysis of the spectrum indicates that the X-ray emission has at least two characteristic temperatures. This is interpreted in the framework of radiative accretion in the core of the cluster. The derived parameters are a cooling time less than or approximately equal to 2 x 10 to the ninth years for the low-temperature gas, a mass accretion rate of approximately 300 solar masses per year, and a characteristic size of 10-20 kpc for the cool gas. The Fe abundance in the core (approximately 0.4) is similar to the Fe abundance averaged over the whole cluster, indicating that Fe emission is not strongly concentrated about NGC 1275. The Si and S abundances are consistent with solar values.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 43
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    Non-linear stability around the triangular libration points (1981)
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    Publication Date: 2011-08-18
    Description: The configuration space around the triangular libration points in the Earth-Moon system is partitioned according to the stability of the motion. The regions around L4 and L5 are established where particles placed with zero initial velocity will librate. The complexity of the partitioning is revealed.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Mar. 198
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  • 44
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    High-resolution observations of the QSO 3C 345 at 1.3 centimeters (1981)
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    Publication Date: 2011-08-18
    Description: High-resolution VLBI observations made at a frequency of 22.235 GHz of the quasar 3C 345 are discussed. Antennas located at the Crimean Astrophysical Observatory, USSR; Onsala, Sweden; Effelsberg, West Germany; and the Haystack Observatory, Massachusetts were employed at 4-min integration times to provide baselines ranging up to 5.5 x 10 to the 8th wavelengths. About 40% of the total flux density of 7.85 Jy, observed in November 1977, and 8.05 Jy, observed in October 1978, is found to originate in an unresolved component of the quasar core in a region less than 0.1 milliarcsec in diameter. The elongated jet-like component of the quasar is observed to contain several peaks of emission extending up to 6 milliarsec from the core which decreased in extent between the two observations.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 243
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  • 45
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    Formation of the terrestrial planets (1980)
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    Publication Date: 2011-08-18
    Description: Two growth mechanisms are identified for the development of the terrestrial planets: (1) gravitational instability leading to a collapse, and (2) gravitational accumulation caused by two-body collisions and coherence. The presence of a dynamically-significant gas phase would not affect either mechanism. Theoretical expressions are presented for the production of giant gaseous protoplanets by gravitational instability within a central dust layer. Gravitational accumulation is discussed with reference to the accumulation of planetesimals from a gas-free circumsolar swarm of bodies. Numerical simulations are given for the early stages of accumulation. The Safronov steady-state velocity is considered, noting that the competition between mutual collisional damping and gravitational acceleration by the members of a solar swarm yields a steady-state velocity distribution where the mean velocity is comparable to the escape velocity of the largest body. A time scale for accumulation is postulated on the basis of the radial distribution of a swarm of non-accreting bodies of equal size. The simultaneous gas-free accumulation of several terrestrial planets is noted. Attention is also given to growth mechanisms in gas-rich interplanetary media.
    Keywords: ASTRONOMY
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  • 46
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    Vectored injection into compressible laminar and turbulent boundary layers (1981)
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    Publication Date: 2011-08-18
    Description: A fundamental analysis of two-dimensional supersonic boundary layer flow, both laminar and turbulent, is presented for a wide range of normal and nonnormal mass-transfer velocities. The analysis is based on the numerical solution of the Navier-Stokes equations, and results are compared with available theoretical and experimental data. Certain cases of practical importance, for which results are not presently available, are referred to.
    Keywords: AERODYNAMICS
    Type: Computer Methods in Applied Mechanics and Engineering; 25; Jan. 198
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  • 47
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    Is the remnant of SN 1006 Crablike (1980)
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    Publication Date: 2011-08-18
    Description: The solid-state spectrometer on the Einstein Observatory and the GSFC cosmic X-ray spectrometer on OSO 8 have observed the X-ray spectrum of SN 1006. The data can be well represented by a power-law model with alpha = 1.2, similar to the spectrum of the Crab Nebula. This is in contrast to the radio and X-ray maps of SN 1006 which show a shell structure more typical of SNR with thermal X-ray emission. The X-ray spectrum is suggestive of nonthermal synchrotron emission, raising the possibility that the remnant of SN 1006 contains a source of relativistic electrons.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 240
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  • 48
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    Three-layer interactive method for computing supersonic laminar separated flows (1980)
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    Publication Date: 2011-08-18
    Description: An interactive model for numerical computation of complicated two-dimensional flowfields including regions of reversed flow is proposed. The present approach is one of dividing the flowfield into three regions, in each of which a simplified mathematical model is applied: (1) outer, supersonic flow for which the full potential equation (hyperbolic) is used; (2) viscous, laminar layer in which the compressible boundary-layer model (parabolic) is used; and (3) recirculating flow modeled by the incompressible Navier-Stokes equations (elliptic). For matching of the numerical solutions in the three layers, two interaction models are developed: one for pressure interaction, the other for interaction between the shear layer and the recirculating flow. The uniform solution for the whole flowfield is then obtained by iteration of the local solutions under the constraints imposed by matching. The three-layer interactive model is used for solution of the flowfield past an asymmetric cavity. The method is shown to be capable of dealing with backflow without encountering problems at separation, characteristic to the boundary-layer approach.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; Nov. 198
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  • 49
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    Report of the panel on theoretical aerodynamics (1981)
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    Publication Date: 2011-08-18
    Description: Interactions between theoretical aerodynamics and the NTF are discussed. The development and validation of computational fluid dynamics computer codes, the determination of Reynolds number scaling laws, and extension of the data bases of entrainment type turbulence models to include high Reynolds number data are recommended areas of study. The major benefit theoretical aerodynamics could have on the NTF is in the quantitative description of wind tunnel wall interference effects.
    Keywords: AERODYNAMICS
    Type: High Reynolds Number Res. - 1980; p 277-286
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  • 50
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    High Reynolds number research requirements for space vehicle design (1981)
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    Publication Date: 2011-08-18
    Description: Requirements of entry vehicle design requiring high Reynolds number wind tunnel testing are discussed. The space shuttle orbiter, development of future space transportation systems, and planetary entry data analysis are considered.
    Keywords: AERODYNAMICS
    Type: High Reynolds Number Res. - 1980; p 265-274
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  • 51
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    Report of the panel on aeroelasticity and unsteady aerodynamics (1981)
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    Publication Date: 2011-08-18
    Description: The status of recommended areas of study for the NTF are reviewed. Transonic and control surface unsteady aerodynamics, and buffet onset and loads are considered. Testing of dynamically scaled flutter models is discussed.
    Keywords: AERODYNAMICS
    Type: High Reynolds Number Res. - 1980; p 237-246
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  • 52
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    Model experience in the Langley 0.3-m transonic cryogenic tunnel (1981)
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    Publication Date: 2011-08-18
    Description: The model building, development, and testing experience gained during 8 years of operation of the 0.3-m Transonic Cryogenic Tunnel (TCT) is summarized. The summary is divided into four portions: (1) models tested in the 0.3-m TCT's original octagonal test section; (2) models tested in the present two dimensional test section; (3) models tested as a part of tunnel calibration and the development of advanced technology airfoils; and (4) development of a new way to construct two dimensional airfoil models. Design requirements imposed on the models by high Reynolds number testing at cryogenic temperatures are reviewed.
    Keywords: AERODYNAMICS
    Type: High Reynolds Number Res. - 1980; p 53-73
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  • 53
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    Radio astronomy (1981)
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    Publication Date: 2011-08-18
    Description: The activities of the Deep Space Network in support of radio astronomy operations during the first quarter of 1981 are reported. Results of the use of a low noise maser are presented, as well as updates in DSN support of experiments sanctioned by the Radio Astronomy Experiment Selection Panel.
    Keywords: ASTRONOMY
    Type: The Telecommun. and Data Acquisition Rept.; p 1-2
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  • 54
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    Radio observation of comet Meier /1978f/ in 18-cm OH lines (1980)
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    Publication Date: 2011-08-17
    Description: Observations of 18-cm OH spectral lines in comet Meier (1978f) with the 1000-ft. Arecibo telescope show spatial resolution of the OH coma by the 2.9 arcmin beam (=3.7 x 10 to the 5th km). The data agree with predictions of the solar Fraunhofer spectrum-pumping theory of comet OH excitation. On the assumption that the OH parent molecule (e.g., H2O) has a Haser-model scale length of about 1.0 x 10 to the 5th km at heliocentric distance 1 AU, an OH scale length of less than 10 to the 6th km, and probably near 1.0 x 10 to the 5th km is derived. Assuming a recently calculated value of the OH lifetime and the solar radiative pumping model, the results indicate an OH production rate of 10 to the 29th Kayser at heliocentric distance 2 AU.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 85; 1-2,; Sept
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  • 55
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    Near infrared photographic sky survey - A field index (1980)
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    Publication Date: 2011-08-17
    Description: The book presents an index of previously cataloged objects located in the fields of the northern sky included in the Steward Observatory Near Infrared Photographic Sky Survey, which was intended to be used for identification purposes in an effort to locate extremely red objects. The objects included in the index were taken from 16 catalogs of bright nebulae, dark nebulae, infrared objects, reflection nebulae, supernova remnants and other objects, and appear with their corresponding field numbers, computed field center coordinates, object name and 1950 epoch equatorial coordinates, as well as supplementary descriptive information as available. An appendix is also provided in which the center coordinates of each field are listed.
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  • 56
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    SS 433 - Intensive 4 month light curves (1980)
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    Publication Date: 2011-08-17
    Description: Photometry covering 100 nights during 1979 July-November is reported, in an unfiltered band (effectively 5200-8000 A), in a V band, and with a few measures in B. Correlation with the 13 day period of Crampton, Cowley, and Hutchings is found in the form of a double-peaked light curve. A more tentative connection with the 164 day 'precession' period suggested by a broad light minimum near a critical phase in the long cycle is found.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 238
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  • 57
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    Near infrared photography with a vacuum-cold camera (1980)
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    Publication Date: 2011-08-17
    Description: Sensitized cooled plates have been obtained of the Orion nebula region and of Sh2-149 in the wavelength ranges 8000 A-9000 A and 9,000 A-11,000 A with a recently designed and constructed vacuum-cold camera. Sensitization procedures are described and the camera design is presented.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 58
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    Stability of planetary orbits in binary systems (1980)
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    Publication Date: 2011-08-17
    Description: The possible existence of stable orbits is investigated in binary systems using Hill's method. Analytical stability conditions are established for satellites, for inner planets and for outer planets, allowing arbitrary values for the mass-ratio of the binary.
    Keywords: ASTRONOMY
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  • 59
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    The promise of multicyclic control (1980)
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    Publication Date: 2011-08-17
    Description: The rough ride a helicopter endures is known to be self-generated. This roughness results in fatiguing blade loads and vibration which can be eliminated or greatly reduced by multicyclic control. Rotor performance may also be improved. Several types of rotors which have employed multicyclic control are reviewed and compared. Their differences are highlighted and their potential advantages and disadvantages are discussed. The flow field these rotors must operate in is discussed, and it is shown that simultaneous elimination of vibration and oscillatory blade loads is not an inherent solution to the roughness problem. The use of rotor blades and energy absorbers is proposed. Input-output relations are considered and a gain control for ROMULAN, a multicyclic controlling computer program, is introduced. Implications of the introduction of multicyclic systems into helicopters are also discussed.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Vertica; 4; 1, 19; 1980
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  • 60
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    On the capture of the Moon (1980)
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    Publication Date: 2011-08-17
    Description: This paper studies the possibility of lunar capture depending on variations of the solar mass under certain well specified conditions and assumptions regarding the behaviour of the three-body dynamical system formed by the Sun, Earth and Moon. It is found that a large amount of decrease in the solar mass (approximately 37%) would be required to allow capture if the model of the planar restricted problem of three bodies is assumed, if the masses of the Earth and Moon did not change and if the angular momentum of the Sun-Earth system did not change. Such large mass-changes of the Sun can not be associated with radiation mass losses only with catastrophic events, such as stellar close approaches.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 21; Apr. 198
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    Noise radiation from the side edges of flaps (1980)
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    Publication Date: 2011-08-17
    Description: The recently observed phenomenon of high noise radiation from the side edges of flaps in flow is investigated by way of a simple two-dimensional model problem. The model is based upon a physical picture of boundary layer vorticity being swept around the edge by spanwise flow on the flap. The model problem is developed and solved and the resulting noise radiation calculated. Further, a mathematical condition for the vortex to be captured by the potential flow and swept around the edge is derived. The results show that the sound generation depends strongly upon the strength of the vorticity and distance from the edge and that it can be more intense than the more common trailing edge noise source in agreement with the experimental observations.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; May 1980
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  • 62
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    Stability aspects of diverging subsonic flow (1980)
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    Publication Date: 2011-08-17
    Description: The paper describes the computation of two-dimensional, subsonic, diverging internal flows and how they differ from the corresponding converging flows. Such diverging or decelerating flows occur in such obvious places as subsonic diffusers and inlets; however, such flows also occur in supersonic nozzles in the presence of a normal shock. The flow instability and its relation to the numerical method used, boundary conditions, and viscous effects are assessed both analytically and numerically. The inviscid flow is shown to be physically unstable and a poor representation of the true viscous flow.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 18; May 1980
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  • 63
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    Measurements of cabin and ambient ozone on B747 airplanes (1980)
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    Publication Date: 2011-08-17
    Description: In response to recent concerns over possibly high ozone levels in the cabins of aircraft flying in the stratosphere, simultaneous measurements of the cabin and ambient ozone levels have been made as part of the NASA Global Atmospheric Sampling Program. Examples of the data taken on commercially operated Boeing 747-100 and 747SP airplanes are given for selected flights, together with summary statistics of over 5600 observations. Cabin ozone levels vary with the ambient level and, for unmodified aircraft, are higher on the 747SP than on the 747-100. Modifications to the ventilation system of the 747SP reduced cabin ozone levels by varying amounts up to a factor of 14.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Journal of Aircraft; 17; Apr. 198
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  • 64
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    The time-of-flight system on the Goddard medium energy gamma-ray telescope (1980)
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    Publication Date: 2011-08-17
    Description: A scintillation counter time-of-flight system has been incorporated into the Goddard 50 cm by 50 cm spark chamber gamma-ray telescope. This system, utilizing constant fraction timing and particle position compensation, digitizes up to 10 ns time differences to six bit accuracy in less than 500 ns. Event selection decisions, discriminating against upward-moving particles, are made prior to spark chamber triggering. The performance of this system during a November 1978 balloon flight is discussed.
    Keywords: ASTRONOMY
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    High-resolution IUE observations of the 1981 eclipse of 32 CYG (1981)
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    Publication Date: 2011-08-18
    Description: 32 Cyg shows a spectacular pure emission line spectrum during eclipse. Six weeks later, most lines, which were observed in emission during eclipse, are seen as P Cygni type profiles with strong absorption components. The lines are formed through line scattering of B star light in the extended atmosphere (wind) of the K supergiant. During eclipse, the emission parts of the P Cyg lines remain visible since the size of the line scattering sphere around the B star is larger than the red giant. Other emission lines are formed in a shock front near the B star (CIV, SiIV, FeIII) and possibly in an accretion disk. The strong FeII UV Mult. 191 lambda lambda 1785-88 A is shown to be formed through optical pumping via FeII UV Mult. 9 photons. The phase dependence of the P Cyg type profiles is modelled by means of line transfer calculations in nonspherical, 3-dimensional geometry with velocity fields.
    Keywords: ASTRONOMY
    Type: Smithsonian Astrophysics Observatory 2nd Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Vol. 1; p 245-259
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  • 66
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    The tilt rotor research aircraft (XV-15) program (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The tilt rotor concept is introduced and the performance capabilities and noise characteristics of the XV-15 aircraft are discussed. In hover, the aircraft is lifted by the two wing tip mounted rotors with the nacelles in the vertical position. In this flight mode, the vehicle is a twin rotor helicopter and is controlled by rotor cyclic and collective controls. The aircraft can fly as a helicopter or tilt the nacelle to the propeller mode and operate as a fixed-wing twin turboprop airplane. It is also possible to stop the conversion at any intermediate angle and fly continuously or reconvert. The rotors are powered by two modified T-53 engines and the power train includes a cross shaft located in the wing, to allow for the engine failure case and still retain power to both rotors.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: American Planning Association Proc. of the Monterey Conf. on Planning for Rotorcraft and Commuter Air Transportation; p 24-33
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  • 67
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    The quiet short-haul research aircraft (1983)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The design concepts, performance capabilities, and projected applications of the Quiet Short-Haul Research Aircraft (QSRA) are discussed. The propulsive lift system of the QSRA provides the lift required for short field operations at low community noise levels. This system consists of four high bipass ratio, geared turbofan engines mounted so that the engine exhaust flows across the upper surface of the wing (upper surface blowing). Large specially shaped flaps behind each engine control the direction of the flow for each phase of flight. A 95 passenger short haul transport based on this technology could operate out of a 2500 foot runway with a combined takeoff and landing 90 EPNdB footprint area of 2.7 sq mi.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: American Planning Association Proc. of the Monterey Conf. on Planning for Rotorcraft and Commuter Air Transportation; p 22-23
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  • 68
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    Optical photometry of SS 433 - 200 nights of data 1979-1980 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results from over 200 nights of optical photoelectric photometry of SS 433 during the period July 1979-October 1980 are presented. The data, taken in unfiltered light, the V band, an interference filter band centered on stationary H-alpha and a far-red band, provide evidence for an underlying 164-day light variation of peak-to-peak amplitudes 0.50 magnitude in V and 0.7 magnitude at 6567 A, and a binary-like variation with period 13.074 days and peak-to-peak amplitudes 0.50 and 0.60 magnitudes, respectively. The 13-day light curves are found to change slightly as a function of phase in the 164-day cycle, while seemingly erratic light fluctuations of up to 1 magnitude in 1 day and about 2 magnitudes in 3-4 days are imposed on both cyclic variations. It is noted that a conventional close-binary model is incapable of accounting for all the observed features, and alternatives involving some sort of luminous, rapidly changing extended low-mass envelope or screen in the binary system must be sought.
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  • 69
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    Infrared photometry of comets Bowell and P/Stephan-Oterma (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Broadband IR photometry in the 1-20 micron range of the comets P/Stephan-Oterma and Bowell shows JHK colors similar to P/Meier and P/Tuttle, which are compatible with the scattering of sunlight by micron-sized grains. In addition, the P/Stephan-Oterma thermal emission was found to have an effective temperature higher than that expected from a blackbody in equilibrium. It is demonstrated that the thermal emission can be fit by models of the dust coma consisting of micron-sized grains, and that most of the flux at all observed wavelengths comes from the dust grains rather than the nucleus.
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  • 70
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    X-ray and VLBI radio observations of the quasars NRAO 140 and NRAO 530 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Einstein X-ray Observatory has confirmed the HEAO 1 detection of the NRAO 140 and NRAO 530 quasars, and found that the low-energy X-ray flux of NRAO 140 is consistent with the high-energy results from the earlier satellite. It is also determined that the X-ray emission from NRAO 530 has either decreased by an order of magnitude, from 1978.0 to 1979.7, or the HEAO 1 field contained a second bright source. The two sources have been observed at 2.8 cm, using a four-station intercontinental VLB array, to find whether the X-ray emission is caused by Compton scattering within the radio components. Dissection of the NRAO 140 into its separate components shows radio parameters that imply a 'Compton problem', in that X-ray emission three orders of magnitude greater than that observed is predicted in one of the components if the source is static. Because the effect is independent of distance, relativistic motion with a Lorentz factor greater than about 40 is required to bring the predicted X-ray flux down to the observed value.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 249
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  • 71
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    Chasing the Space Shuttle (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The use and modifications of the T-38 aircraft as chase planes for the STS-1 landing are discussed. Two planes tracked the approach at Edwards AFB, with the lead plane responsible for airspeed and altimetry calibration, technical photography, landing gear status, and height-above-touchdown calls; the second T-38 provided live TV and back-up. Modifications included extension of the landing gear extension speed, increasing the area of the speedbrakes, and installation of a TV system; the goal was to stay with the Shuttle below 40,000 ft while it descended at 15,000 ft/min. Ten T-38's were modified and the deployment of lead and back-up crews during the first Shuttle flight is outlined. Western Test Range C-band radar data of the Orbiter position were transformed into intercept coordinates and VHF relayed to the chase craft. Photographs were taken of the right and left sides and underside of the Shuttle while flying with the speedbrake up to match the Shuttle speed.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 72
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    Development of a comprehensive analysis for rotorcraft. II - Aircraft model, solution procedure and applications (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The development of a comprehensive analytical model of rotorcraft aerodynamics and dynamics is described. Particular emphasis is given to describing the reasons behind the choices and decisions involved in constructing the model. The analysis is designed to calculate rotor performance, loads and noise; helicopter vibration and gust response; flight dynamics and handling qualities; and system aeroelastic stability. It is intended for use in the design, testing and evaluation of a wide class of rotors and rotorcraft and to be the basis for further development of rotary wing theories. The general characteristics of the geometric, structural, inertial and aerodynamic models used for the rotorcraft components are described, including the assumptions introduced by the chosen models and the resulting capabilities and limitations. Finally, some examples from recent applications of the analysis are given.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Vertica; 5; 3, 19; 1981
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  • 73
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    Observations of SMC X-1 with the monitor proportional counter on the Einstein /HEAO 2/ X-ray Observatory - The pulse period and its history (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The results of the sixth determination of the pulse period of the X-ray source SMC X-1 are presented. The observations were made in April 1979. The pulse period at this epoch was found to be (0.713683 + or - 0.000032) s referred to phase zero of the binary motion. This result together with all available historical data is utilized to quantify the observed trend toward spin-up. It is found that simple secular trends are not applicable. This finding is interpreted as evidence for additional variations in the pulse period. The obtained results are discussed in the context of present theoretical models for period variations in the binary pulsating X-ray sources. The apparent absence of spin-down episodes in the period history of SMC X-1 is also considered.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 74
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    Two-component X-ray emission from RS Canum Venaticorum binaries (1981)
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    Publication Date: 2011-08-18
    Description: A summary is presented of results from the Solid State Spectrometer on the Einstein Observatory for seven RS CVn binaries. The spectra of all require two emission components, evidenced by line emission characteristics of plasma at 4-million to 8-million K and bremsstrahlung characteristic of 20-million to 100-million K. The data are interpreted in terms of magnetic coronal loops similar to those seen on the sun, although with different characteristic parameters. The emission regions could be defined by separate magnetic structures. For pressures less than 10 dynes/sq cm the low temperature plasma would be confined within the stellar radii, while the high temperature plasma would, for the synchronous, close binaries, fill the binary orbits. However, for loop pressures exceeding 100 dynes sq cm, the high temperature components would also be confined to within the stellar radii, in loops covering only small fractions of the stellar surfaces. While the radio properties and the occurrence of X-ray flares suggest the larger emission regions, the observations of time variations leave the ambiguity unresolved.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 246
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  • 75
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    Pulsar gamma-rays - Spectra, luminosities, and efficiencies (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The general characteristics of pulsar gamma-ray spectra are presented for a model in which the gamma rays are produced by curvature radiation from energetic particles above the polar cap and attenuated by pair production. It is found that the shape of the spectrum depends on pulsar period, magnetic field strength, and primary particle energy. Comparing numerically calculated spectra with the observed spectra of the Crab and Vela pulsars, it is determined that primary particles must be accelerated to energies of approximately 3 x 10 to the 7th m c-squared. A general formula is determined for pulsar gamma-ray luminosity; it is found to depend on period and field strength.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 245
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  • 76
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    The Uranus occultation of 10 June 1979. I - The rings (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 86; Apr. 198
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  • 77
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    Infrared observations of AE Aquarii (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Broadband infrared observations of the cataclysmic variable AE Aquarii are reported. The observations were obtained in the J, H, K and L filters with the InSb photometer attached to the 1-m telescope of the European Southern Observatory. The infrared energy distribution observed from 0.35 to 3.5 microns for phase 0.5 suggests a spectral type of K5 V for the secondary and a distance to the system of approximately 70 pc if an absolute magnitude of 7.3 is assumed. Monitoring of the flux at 2.2 microns reveals a variability with an amplitude of approximately 0.3 magnitude over one third of the orbital period, the nature of which is under investigation.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 93
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  • 78
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    Effectiveness of leading-edge vortex flaps on 60 and 75 degree delta wings (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A series of wind tunnel tests were run on 60 and 75 deg sweep delta wings to examine the effectiveness of leading-edge vortex flaps. Tests results showed that leading-edge vortex flaps are effective in giving large increases in lift-to-drag ratio and decreases in drag over a wide range of angle of attack. Tests on inverted flaps on the 60 deg delta wing showed substantial increases in lift and drag and may indicate a possibility of using inverted flaps on delta wings in the landing portion of flight. The 60 deg data were compared with that for a 75 deg sweep delta wing confirming that leading-edge vortex flap effectiveness is stronger as sweep is increased. Pitching moment effects due to vortex flaps use were also examined.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 18; Apr. 198
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  • 79
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    An X-ray survey of nine historical novae (1981)
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    Publication Date: 2011-08-18
    Description: The Einstein Observatory Imaging Proportional Counter has been used to search for X-ray emission from nine nearby historical novae. Six of the novae have been detected with estimated X-ray intensities between 0.1 and 4 keV of 10 to the -13th to 10 to the -11th erg/sq cm-sec, comparable to the intensities of previously detected cataclysmic variables. The X-ray intensity of one of the novae, V603 Aql, varies over times of several hundred seconds. The data suggest a correlation between the decay rate of the historical outburst and the current X-ray luminosity. Alternatively, the X-ray luminosity may be related to the inclination of the binary system.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 244
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  • 80
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    Pulsar and diffuse contributions to observed galactic gamma radiation (1981)
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    Publication Date: 2011-08-18
    Description: The first calculation of a gamma-ray production spectrum from pulsars in the Galaxy, along with a statistical analysis of data on 328 known radio pulsars, are presented. The implications of this point source contribution to the general interpretation of the observed galactic gamma-ray spectrum are indicated. The contributions from diffuse interstellar cosmic-ray induced production mechanisms are then re-examined, concluding that pulsars may be contributing significantly to the galactic gamma-ray emission.
    Keywords: ASTRONOMY
    Type: Nature; 290; Mar. 26
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  • 81
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    Variable X-ray spectra of BL Lacertae objects - HEAO 1 observations of PKS 0548 - 322 and 2A 1219 + 305 (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 243
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  • 82
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    Phase-correlated P Cygni profile variations of the C III multiplet in UW Canis Majoris (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The interacting close binary system UW CMa has been observed, in the wavelength range from 1161 to 1188 A, continuously during a complete orbital cycle in 1979 with the Copernicus (OAO-3) U2 spectrometer. The C III multiplet at 1175 A, observed as a P Cygni feature, exhbits a clear dependence on the orbital phase of the binary; the radial velocity variation of this feature lags behind that of the O7 primary component by 0.1 orbital phase, which agrees with the anticipations in an earlier study by the same authors. The radiation-driven matter, flowing out of the binary, originates in the primary component.
    Keywords: ASTRONOMY
    Type: Astronomy and Astrophysics; 94; 2, Fe; Feb. 198
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  • 83
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    Partially confined multiple jet mixing (1981)
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    Publication Date: 2011-08-18
    Description: Results of hot-wire measurements in an incompressible partially confined jet issuing from an array of rectangular nozzles, equally spaced with their small dimensions aligned are presented. The quantities measured include mean velocity and the Reynolds stress in the two central planes of the jet at stations covering up to 115 widths (small dimension of a nozzle) downstream of the nozzle exit. For downstream distances greater than 60 widths, the flowfield is observed to be nearly homogenous and the turbulence appears to be quite similar to that of a grid generated turbulence.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 19; Mar. 198
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  • 84
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    Unsteady Newton-Busemann flow theory. I - Airfoils (1981)
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    Publication Date: 2011-08-18
    Description: Newtonian flow theory for unsteady flow at very high Mach numbers is completed by the addition of a centrifugal force correction to the impact pressures. The correction term is the unsteady counterpart of Busemann's centrifugal force correction to impact pressures in steady flow. For airfoils of arbitary shape, exact formulas for the unsteady pressure and stiffness and damping-in-pitch derivatives are obtained in closed form, which require only numerical quadratures of terms involving the airfoil shape. They are applicable to airfoils of arbitrary thickness having sharp or blunt leading edges. For wedges and thin airfoils these formulas are greatly simplified, and it is proved that the pitching motions of thin airfoils of convex shape and of wedges of arbitrary thickness are always dynamically stable according to Newton-Busemann theory. Leading-edge bluntness is shown to have a favorable effect on the dynamic stability; on the other hand, airfoils of concave shape tend toward dynamic instability over a range of axis positions if the surface curvature exceeds a certain limit. As a byproduct, it is also shown that a pressure formula recently given by Barron and Mandl for unsteady Newtonian flow over a pitching power-law shaped airfoil is erroneous and that their conclusion regarding the effect of pivot position on the dynamic stability is misleading.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 19; Mar. 198
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  • 85
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    Evidence of imbedded vortices in a three-dimensional shear flow (1981)
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    Publication Date: 2011-08-18
    Description: Vortex phenomena encountered in an investigation of the streamwise development of the three-dimensional wake region behind the tip of a three-dimensional wedge model are reported. Pressure profiles were measured by pitot probes downstream of a tip with a nearly constant surface pressure level and a nearly continuous surface curvature in a blowdown air tunnel operating at Mach 6. Rather than the simple three-dimensional quasi-parallel shear flow expected, the measurements indicated the presence of a flow with large deficits in longitudinal pitot pressure, which are usually associated with the core region of quasi-steady longitudinal vortices. Vapor screen flow visualizations also support the presence of longitudinal vortices located primarily in the tip region and evidently forming in the vicinity of the wake neck. An increase in overall wake thickness by 100% is also observed. The origin of the vortices as quasi-steady Taylor-Gortler vortices generated in the concavely curved shear layer near the wake neck is considered. It is pointed out that the existence of longitudinal vortexes suggests that three-dimensional turbulence modeling may be much more difficult than previously supposed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 19; Mar. 198
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  • 86
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    VRI photometry of selected SAO stars (1981)
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    Publication Date: 2011-08-18
    Description: Johnson V, R, and I photoelectric photometry has been obtained for 199 SAO stars in support of the Near Infrared Photographic Sky Survey. These data are utilized in the calibration of survey photographs and are presented here to assist other programs reliant upon access to photometry in the photographic infrared.
    Keywords: ASTRONOMY
    Type: Astronomical Society of the Pacific; vol. 92
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  • 87
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    Ultraviolet, X-ray, and infrared observations of HDE 226868 equals Cygnus X-1 (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: During April, May, and July of 1978, HDE 226868, the optical counterpart of Cygnus X-1, was repeatedly observed in the ultraviolet with the IUE satellite. Some X-ray and infrared observations have been made during the same period. The general shape of the spectrum is that expected from a late O supergiant. Strong absorption features are apparent in the ultraviolet, some of which have been identified. The equivalent widths of the most prominent lines appear to be modulated with the orbital phase. This modulation is discussed in terms of the ionization contours calculated by Hatchett and McCray, for a binary X-ray source in the stellar wind of the companion.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 242
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  • 88
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    The necessity of new dynamical theories of the planets (1980)
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    Publication Date: 2011-08-18
    Keywords: ASTRONOMY
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  • 89
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    Design for supercommuters (1981)
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    Publication Date: 2011-08-18
    Description: Action to be taken to prepare to implement efficient, modern commuter aircraft for the 1990s is outlined. The increase in the contribution of jet fuel costs to aircraft direct operating costs (DOC) is noted as the motivation for the introduction of turboprop-powered commuter aircraft, which use 15-20% less fuel per seat mile at short stage lengths, to replace larger jet transports. Designs proposed by various manufacturers which will make use of existing technology for 19-, 30- and 50-seat aircraft capable of carrying a full payload of passengers and baggage for 600 n mi and optimized for minimum DOC over a 100-n mi stage length are presented, and the improvements in fuel usage, DOC and passenger comfort to be obtained with the use of advanced technology are pointed out. The goals and considered technologies of the dedicated small-transport aircraft technology program recommended by a commuter air transport subcommittee of the NASA Advisory Council Aeronautics Advisory Committee to speed the development of commuter technology are then presented, with attention given to efforts of analysis, design and testing of propulsion systems, structures, aerodynamics and systems intended to result in 16-24% savings in DOC and up to 40% savings in fuel. The commuter development plans of various manufacturers are also indicated.
    Keywords: AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Type: Astronautics and Aeronautics; 19; Feb. 198
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  • 90
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    Deformation of a line-element in the phase space at the triangular libration point (1981)
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    Publication Date: 2011-08-18
    Description: The flow in the projection of the phase space into the configuration space is presented in the neighborhood of a neutrally (or critically) stable equilibrium point in the restricted problem of three bodies. The projection is a line-element every point of which has zero initial velocity. After the elapse of various times the mapping (the rotations and elongations) of the line-element is described showing chaotic behavior.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Feb. 198
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  • 91
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    Stability of outer planetary systems (1981)
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    Publication Date: 2011-08-18
    Description: The conditions for stability in the Liapunov-Hill sense of outer planetary systems are given in terms of radii of planetary orbits. The outer planets of the solar system are found stable and the possible existence of other than the presently known planets between Jupiter and Pluto are indicated. The existence of other planetary systems with arbitrary mass ratios of the primaries is suggested, and the stability conditions for such systems are derived.
    Keywords: ASTRONOMY
    Type: Celestial Mechanics; 23; Jan. 198
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  • 92
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    The luminosity functions of the 1969 Perseid and Orionid meteor showers (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Observations of the 1969 Perseid and Orionid meteor showers are presented and used to derive luminosity functions for the 288 Perseids and 56 Orionids detected. Visual counts were performed under very good to excellent seeing conditions at the times of peak activities, and the brightnesses of the meteors were estimated to the nearest magnitude by comparison with the magnitudes of known objects. Maximum likelihood estimates of the power law index of the luminosity function of 1.56 + or - 0.06 for the Perseids and of 1.85 + or - 0.1 for the Orionids are obtained which are lower than the values found by other investigators. Under the assumption that the luminosity of visual meteors is proportional to their mass, the luminosity function power law may also be used to characterize the mass function.
    Keywords: ASTRONOMY
    Type: Icarus; 43; Sept
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  • 93
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    On the detection of other planetary systems - Detection of intrinsic thermal radiation (1980)
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    Publication Date: 2011-08-18
    Description: There is currently no unambiguous observational evidence for the existence of other planetary systems. One possible way to detect and study such systems is infrared observations of continuum blackbody radiation from planets revolving around other stars. It is shown that the effective temperature of large planets revolving around mid- to late-spectral-type main-sequences stars is set by energy sources internal to the planet rather than by equilibrium with the radiation field of the central star, making them easier to detect than had been previously thought. Consideration is given to the two major observational constraints on detecting planetary companions to nearby stars, namely, angular resolution and sensitivity. A comparison is made between the performance of an ambient (T 200 K), single-aperture telescope and a cooled interferometer. In each case the required aperture (baseline) is large (in the 10-m class), but consistent with Shuttle launch capability.
    Keywords: ASTRONOMY
    Type: Icarus; 43; Sept
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  • 94
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    In quest of telescopes (1981)
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    Publication Date: 2011-08-18
    Description: This article deals with the author's decision to study star formation and reviews the early days of infrared astronomy at O'Brien Observatory. The infrared equipment used to observe the T Tauri variable class is described.
    Keywords: ASTRONOMY
    Type: Sky and Telescope; 61; Feb. 198
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  • 95
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    Results from the 10 March 1977 occultation by the Uranus system (1980)
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    Details
    Publication Date: 2011-08-18
    Description: Timings of occultation events observed at Perth, Australia during the appulse of Uranus to SAO 158687 are presented. In addition to pre- and post-appulse observations of the alpha ring, a search of the data confirms events by the '4', '5', and '6' rings on the pre-appulse side of Venus, and the '5' and beta rings on the post-appulse side. A table of other suspected events obtained from a statistical search of the data down to the same level of significance as the '4', '5', and '6' events is presented. A fairly strong 'event', so far unconfirmed, is noted near the 5:1 Miranda resonance orbit. Examination of the light curves at high time resolution indicates that the alpha ring was, during this aspect, about 10 km in radial extent and about 50% transparent.
    Keywords: ASTRONOMY
    Type: Astronomical Journal; 85; Dec. 198
    Format: text
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  • 96
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    The hard X-ray pulse profile of GX 1+4 (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results are reported from 1976 and 1977 observations of the galactic center X-ray source GX 1+4. On these two occasions, epoch folding at twice the previously reported period of about two minutes has resulted in an asymmetry between the shapes of the two resultant peaks in the light curve, indicating that the true period may be about four minutes. Mean intensity is shown to vary from pulse to pulse.
    Keywords: ASTRONOMY
    Type: Astrophysical Journal; vol. 240
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  • 97
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    The Space Telescope Observatory (1980)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Space Telescope is an international astronomical observatory which will be placed into a low earth orbit in December 1983. The observatory will provide astronomers the opportunity to use five different instruments (wide field/planetary camera, faint object camera, high-resolution spectrograph, faint-object spectrograph, and high speed photometer), and to do astrometry with the use of the fine guidance sensors used primarily for pointing control. These instruments, the spectral range available above the earth's atmosphere, and the spatial resolution available from the combination of a near-diffraction limited 94-in. primary mirror and the stability provided by the Pointing Control System provide a tremendous potential to the astronomical community.
    Keywords: ASTRONOMY
    Type: Journal of the Astronautical Sciences; 28; Apr
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  • 98
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    Proposed aeroelastic and flutter tests for the National Transonic Facility (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Tests that can exploit the capability of the NTF and the transonic cryogenic tunnel, or lead to improvements that could enhance testing in the NTF are discussed. Shock induced oscillation, supersonic single degree control surface flutter, and transonic flutter speed as a function of the Reynolds number are considered. Honeycombs versus screens to smooth the tunnel flow and a rapid tunnel dynamic pressure reducer are recommended to improve tunnel performance.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center High Reynolds Number Res. - 1980; p 153-161
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  • 99
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    Report of the wind tunnel/flight correlation panel (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Basic calibration of the tunnel prior to conducting any tests, the areas requiring wind tunnel/flight test correlation for validating the NTF, and recommendations for achieving validation of the NTF are discussed.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Research Center High Reynolds Number Res. - 1980; p 249-262
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  • 100
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    High lift technology (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The NASA Langley high lift technology program is reviewed and elements of the program which are considered Reynolds number sensitive are discussed. The Energy Efficient Transport (EET) and Supersonic Cruise Research (SCR) models proposed for high lift studies in the National Transonic Facility (NTF) are described. Recommendations regarding the NTF facility and test techniques are presented.
    Keywords: AERODYNAMICS
    Type: High Reynolds Number Res. - 1980; p 197-213
    Format: text
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