ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • AERODYNAMICS  (851)
  • ASTRONOMY  (756)
  • 2000-2004
  • 1980-1984  (1.607)
  • 1975-1979
  • 1960-1964
  • 1925-1929
  • 1984  (857)
  • 1981  (750)
Sammlung
Schlagwörter
Erscheinungszeitraum
  • 2000-2004
  • 1980-1984  (1.607)
  • 1975-1979
  • 1960-1964
  • 1925-1929
Jahr
  • 1
    facet.materialart.
    Unbekannt
    Curved-flow, rolling-flow, and oscillatory pure-yawing wind-tunnel test methods for determination of dynamic stability derivatives (1981)
    In:  CASI
    Details
    Publikationsdatum: 2011-10-14
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: AGARD Dyn. Stability Parameters; 13 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 2
    facet.materialart.
    Unbekannt
    The PDS-VAX intelligent plate scanning system of Trieste Astronomical Observatory (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: An intelligent subsystem for interfacing a PDS1010A digital microdensitometer to a DEC DR11W DMA 16 bit UNIBUS port in DEC VAX VMS environment was tested. The subsystem employs two MOTOROLA M68000 microprocessors with 128 KB data memory. The PDS primitives and the user defined high level scanning functions and preprocessing modules are loaded from the host computer into two 8 KB RAM memories in the microprocessors using a dedicated PDS control language. The subsystem is planned to employ a nonstandard photomultiplier electronics. Two design schemes were tested: (1) based on three amplifiers of gain 10 cascaded and multiplexed to a 12 bit AD converter, and (2) based on a single amplifier of gain 100 and two 14 bit AD converters.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Goddard Space Flight Center Astron. Microdensitometry Conf.; p 175-187
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 3
    facet.materialart.
    Unbekannt
    Status of advanced airfoil tests in the Langley 0.3-meter transonic cryogenic tunnel (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A joint NASA/U.S. industry program to test advanced technology airfoils in the Langley 0.3-meter Transonic Tunnel (TCT) was formulated under the Langley ACEE Project Office. The objectives include providing U.S. industry an opportunity to compare their most advanced airfoils to the latest NASA designs by means of high Reynolds number tests in the same facility. At the same time, industry would again experience in the design and construction of cryogenic test techniques. The status and details of the test program are presented. Typical aerodynamic results obtained, to date, are presented at chord Reynolds number up to 45 x 10(6) and are compared to results from other facilities and theory. Details of a joint agreement between NASA and the Deutsche Forschungs- und Versuchsantalt fur Luft- and Raumfahrt e.V. (DFVLR) for tests of two airfoils are also included. Results of these tests will be made available as soon as practical.
    Schlagwort(e): AERODYNAMICS
    Materialart: Advan. Aerodyn.: Selected NASA Res.; p 37-53
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 4
    facet.materialart.
    Unbekannt
    Spectroscopy in X-ray astronomy (1981)
    In:  CASI
    Details
    Publikationsdatum: 2006-06-04
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 5
    facet.materialart.
    Unbekannt
    Far ultraviolet astronomy using the FAUST telescope (1981)
    In:  CASI
    Details
    Publikationsdatum: 2006-06-04
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 6
    facet.materialart.
    Unbekannt
    Component testing for dynamic model verification (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Dynamic model verification is the process whereby an analytical model of a dynamic system is compared with experimental data, adjusted if necessary to bring it into agreement with the data, and then qualified for future use in predicting system response in a different dynamic environment. These are various ways to conduct model verification. The approach taken here employs Bayesian statistical parameter estimation. Unlike curve fitting, whose objective is to minimize the difference between some analytical function and a given quantity of test data (or curve), Bayesian estimation attempts also to minimize the difference between the parameter values of that funciton (the model) and their initial estimates, in a least squares sense. The objectives of dynamic model verification, therefore, are to produce a model which: (1) is in agreement with test data; (2) will assist in the interpretation of test data; (3) can be used to help verify a design; (4) will reliably predict performance; and (5) in the case of space structures, will facilitate dynamic control.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Recent Experiences in Multidisciplinary Analysis and Optimization, Part 2; 15 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 7
    facet.materialart.
    Unbekannt
    Post and a random-walk search mode (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Multidisciplinary analysis often requires optimization of nonlinear systems that are subject to constraints. Trajectory optimization is one example of this situation. The Program to Optimize Simulated Trajectories (POST) was used successfully for a number of problems. The purpose is to describe POST and a new optimization approach that has been incorporated into it. Typical uses of POST will also be illustrated. The projected-gradient approach to optimization is the preferred option in POST and is discussed. A new approach to optimization, the random-walk approach, is described, and results with the random-walk approach are presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: Recent Experiences in Multidisciplinary Analysis and Optimization, Part 2; 23 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 8
    facet.materialart.
    Unbekannt
    Wall interference measurements for three-dimensional models in transonic wind tunnels: Experimental difficulties (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The purpose is not to provide a detailed discussion of several wall interference experiments, but rather to use these experiments (recently accomplished in the Boeing Transonic Wind Tunnel (BTWT) to illustrate the problems associated with many of the measurements required by current wall interference assessment/correction (WIAC) procedures. The wall correction to lift is emphasized. It is shown that, because conventional tunnels and relatively small models continue to be used, the flow field or flow boundary measurements to be made impose severe requirements on the experiment itself. In some cases, existing instrumentation and test techniques may not be adequate to obtain the data accuracies needed.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 21-42
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 9
    facet.materialart.
    Unbekannt
    Adaptation of a four-wall interference assessment/correction procedure for airfoil tests in the 0.3-m TCT (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Based upon limited, initial observations of wall interference corrections obtained for one airfoil test, there is a need for assessing the upstream flow direction. If there is no direct measurement then a two-pass correction procedure similar to the one described here is required. Questions have arisen pertaining to the correct interpretation of the pressure coefficients measured on the slats of a slotted tunnel wall, the interpretation of just what the calculated equivalent body encompasses or should include, and what can or should be considered as quantitative criteria for data correctability. Further studies using this modified procedure will address these questions. Hopefully, a meaningful WIAC procedure can be validated for the airfoil tests in the 0.3-m TCT.
    Schlagwort(e): AERODYNAMICS
    Materialart: Wind Tunnel Wall Interference Assessment and Correction, 1983; p 393-414
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 10
    facet.materialart.
    Unbekannt
    Some experience with Barnwell-Sewall type correction to two-dimensional airfoil data (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A series of airfoils were tested in the Langley 0.3-Meter Transonic Cryogenic Tunnel (TCT) at Reynolds numbers from 2 to 50 million. The 0.3-m TCT is equipped with Barnwell slots designed to minimize blockage due to the tunnel flow and ceiling. This design suggests that sidewall corrections for blockage is needed, and that a lifting airfoil produces a change in angle of attack. Sidewall correction methods were developed for subsonic and subsonic-transonic flow. Comparisons of theory with experimental data obtained in the 0.3-m TCT for two airfoils, the British NPL 9510 and the German R-4 are presented. The NPL 9510 was tested as part of the NASA/United Kingdom Joint Aeronautical Program and R-4 was tested as part f the DFVLR/NASA Advanced Airfoil Research Program. For the NPL 9510 airfoil, only those test points that one would anticipate being difficult to predict theoretically are presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: Wind Tunnel Wall Interference Assessment and Correction, 1983; p 375-392
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 11
    facet.materialart.
    Unbekannt
    Experiences with a high-blockage model tested in the NASA Ames 12-foot pressure wind tunnel (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Representation of the flow around full-scale ships was sought in the subsonic wind tunnels in order to a Hain Reynolds numbers as high as possible. As part of the quest to attain the largest possible Reynolds number, large models with high blockage are used which result in significant wall interference effects. Some experiences with such a high blockage model tested in the NASA Ames 12-foot pressure wind tunnel are summarized. The main results of the experiment relating to wind tunnel wall interference effects are also presented.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 345-360
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 12
    facet.materialart.
    Unbekannt
    An inerference assessment approach for a three-dimensional slotted tunnel with sparse wall pressure data (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The various procedures referred to as wall interference assessment and correction procedures presume the existence of a surface distribution of data (usually static pressure) measured over a surface on or near the tunnel walls for each test point to be assessed. An alternative approach in which a reasonably sophisticated computer model of the test section flow would be fitted parametrically to a sparse set of measured data is presented. The measurements provides line distributions of static pressure near the center lines of the top, side and bottom walls. The development of a test section model incorporating explicit recognition of discrete slots of finite length with controlled flow reentry into the solid wall downstream portion of the tunnel is shown.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center. Wind Tunnel Wall Interference Assessment and Correction, 1983; p 323-334
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 13
    facet.materialart.
    Unbekannt
    Interference from slotted walls (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Wall interference is made predominant in tunnel models and by wall geometries to facilitate the study of slot flow. The viscous effects in slots are studied by two dimensional measurements of flow. Wall interference is assessed by measuring pressure distributions at two levels near the walls. Interference on lifting delta wings is calculated. Pressure distributions at inner boundaries show basis axisymetries between the pressure side and the suction side, pointing to the necessity of having wider slots on the pressure side.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 293-300
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 14
    facet.materialart.
    Unbekannt
    Development in UK of a method for calculating tunnel wall corrections from flow measurements (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Classical methods for calculation of wall corrections which are not satisfactory for a number of flows of interest are discussed. To meet these objections, a number of methods were developed which use measurements of the low at or close to the tunnel walls as an outer boundary condition to define wall interference. The development, assessment and application of one such method is summarized.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 259-271
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 15
    facet.materialart.
    Unbekannt
    NLR activities in the field of wind tunnel wall interference (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Measured field data as a boundary condition for calculating the interference flow field were applied. They are divided into two categories. In the first category, the field data must consist of distributions of a single velocity component, and an accurate estimate of the hypothetical free air contribution of the model to this component is required. The differences between measured values and estimated model contributions are attributed to wall interference and they establish the boundary condition. The associated field data measurements are simple, yet the necessary model representation generally is a serious drawback. The second category requires field data which consist of velocity vector distributions at the price of multicomponent measurements, but at the profit that no information at all is required about the model. In solid wall test sections, the price is reduced to virtually zero but the profit remains.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 221-229
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 16
    facet.materialart.
    Unbekannt
    Performance of two transonic airfoil wind tunnels utilizing limited ventilation (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A limited-zone ventilated wall panel was developed for a closed-wall icing tunnel which permitted correct simulation of transonic flow over model rotor airfoil sections with and without ice accretions. Candidate porous panels were tested in the Ohio State University 6- x 12-inch transonic airfoil tunnel and result in essentially interference-free flow, as evidenced by pressure distributions over a NACA 0012 airfoil for Mach numbers up to 0.75. Application to the NRC 12- x 12-inch icing tunnel showed a similar result, which allowed proper transonic flow simulation in that tunnel over its full speed range.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 165-170
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 17
    facet.materialart.
    Unbekannt
    Investigations of flow field perturbations induced on slotted transonic-tunnel walls (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The free-stream interference caused by the flow through the slotted walls of the test sections of transonic wind tunnels has continuously a problem in transonic tunnel testing. The adaptive-wall transonic tunnel is designed to actively control the near-wall boundary conditions by sucking or blowing through the wall. In order to make the adaptive-wall concept work, parameters for computational boundary conditions must be known. These parameters must be measured with sufficient accuracy to allow numerical convergence of the flow field computations and must be measured in an inviscid region away from the model that is placed inside the wind tunnel. The near-wall flow field was mapped in detail using a five-port cone probe that was traversed in a plane transverse to the free-stream flow. The initial experiments were made using a single slot and recent measurements used multiple slots, all with the tunnel empty. The projection of the flow field velocity vectors on the transverse plane revealed the presence of a vortex-like flow with vorticity in the free stream. The current research involves the measurement of the flow field above a multislotted system with segmented plenums behind it, in which the flow is controlled through several plenums simultaneously. This system would be used to control a three-dimensional flow field.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 119-142
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 18
    facet.materialart.
    Unbekannt
    Assessment of lift- and blockage-induced wall interference in a three-dimensional adaptive-wall tunnel (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A three-dimensional adaptive-wall wind tunnel experiment was conducted at Ames Research Center. This experiment demonstrated the effects of wall interference on the upwash distribution on an imaginary surface surrounding a lifting wing. This presentation demonstrates how the interference assessment procedure used in the adaptive-wall experiments to determine the wall adjustments can be used to separately assess lift- and blockage-induced wall interference in a passive-wall wind tunnel. The effects of lift interference on the upwash distribution and on the model lift coefficient are interpreted by a simple horseshoe vortex analysis.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 89-100
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 19
    facet.materialart.
    Unbekannt
    Wind tunnel wall interference in closed, ventilated and adaptive test sections (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A wall interference correction method for closed rectangular test sections was developed which uses measured wall pressures. Measurements with circular discs for blockage and a rectangular wing as a lift generator in a square closed test section validate this method. These measurements are intended to be a basis of comparison for measurements in the same tunnel using ventilated (in these case, slotted) walls. Using the vortex lattice method and homogeneous boundary conditions, calculations were performed which show sufficiently high pressure levels at the walls for correction purposes in test sections with porous walls. In Gottingen, an adaptive test section (which is a deformable rubber tube of 800 mm diameter) was built and a computer program was developed which is able to find the necessary wall adaptation for interference-free measurements in a single step. To check the program prior to the first run, the vortex lattice method was used to calculate wall pressure distributions in the nonadapted test section as input data for the one-step method. Comparison of the pressure distribution in the adapted test section with free-flight data shows nearly perfect agreement. An extension of the computer program can be made to evaluate the remaining interference corrections.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 61-78
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 20
    facet.materialart.
    Unbekannt
    Review of the advanced technology airfoil test program in the 0.3-meter transonic cryogenic tunnel (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The following areas were addressed: interchangeable test sections in the 0.3-M Transonic Cryogenic Tunnel (TCT); typical airfoil installation; airfoil capability; advanced technology airfoil test (ATAT); effects of the Reynolds number on the normal force coefficient; effects of the Reynolds number on the drag coefficient; and comparison of experimental results with theory.
    Schlagwort(e): AERODYNAMICS
    Materialart: Wind Tunnel Wall Interference Assessment and Correction, 1983; p 361-374
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 21
    facet.materialart.
    Unbekannt
    Determination of equivalent model geometry for tunnel wall interference assessment/correction (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A formula for the determination of equivalent model geometry with two variables measured at the interface is derived, based on two dimensional subsonic flow. This predicted model profile is a reasonable initial estimate for transonic flow as long as the sonic region does not reach the interface. A general formula is given in two forms. One is in terms of complex variable functions and the other is an integral equation. The complex-function formula has the advantage of using analytic expressions. The integral equation form requires a numerical solution after assuming the model geometry as a polynomial function. Examples are given to illustrate the application of the formulas.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 335-342
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 22
    facet.materialart.
    Unbekannt
    An analytic solution to the classical two-body problem with drag (1981)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Houston Univ. The 1981 NASA ASEE Summer Fac. Fellowship Program, Vol. 2; 22 p
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 23
    facet.materialart.
    Unbekannt
    STEP flight experiments Large Deployable Reflector (LDR) telescope (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-04-03
    Beschreibung: Flight testing plans for a large deployable infrared reflector telescope to be tested on a space platform are discussed. Subsystem parts, subassemblies, and whole assemblies are discussed. Assurance of operational deployability, rigidization, alignment, and serviceability will be sought.
    Schlagwort(e): ASTRONOMY
    Materialart: NASA. Langley Research Center STEP Expt. Requirements; p 257-278
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 24
    facet.materialart.
    Unbekannt
    Wind tunnel wall interference correction for aircraft models (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Wall interference correction procedures seek to determine the required changes in certain flow or geometric parameters so that the difference between the flow properties at the model's surface in the tunnel and free air are minimized. A transonic and a linear correction procedure were developed for aircraft models. In addition to Mach number and angle of attack corrections, an estimate of the accuracy of the corrections is provided by the transonic correction procedure. Lift, pitching moment and pressure measurements near the tunnel walls are required. The efficiency and accuracy of the correction procedure are improved. Moreover, correction of both the wing and tail angles of attack is allowed. The procedure is valid for transonic as well as subcritical flows. However, for subcritical flows further approximations and simplifying assumptions are made, leading to a very simple and efficient correction procedure.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center. Wind Tunnel Wall Interference Assessment and Correction, 1983; p 301-322
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 25
    facet.materialart.
    Unbekannt
    Tunnel constraint for a jet in crossflow (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A facet of a unified tunnel correction scheme which uses wall pressures to determine tunnel induced blockage and upwash is described. With this method, there is usually no need to use data concerning model forces or power settings to find the interference; it follows directly from the pressures and tunnel dimensions. However, highly inclined jets do not produce good pressure signatures and are highly three dimensional, so they must be treated differently. Flow modeling is also discussed.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center. Wind Tunnel Wall Interference Assessment and Correction, 1983; p 273-290
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 26
    facet.materialart.
    Unbekannt
    Progress in wind tunnel wall interference assessment/correction procedures at the NAE (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Wall corrections as a function of wall porosity in the transonic wall interference problem was assessed. Effective porosities primarily for the two dimensional case were established as follows: (1) comparison of experimental data for two geometrically similar models of different chord/height ratio, an overall value of wall porosity could be deduced; (2) theoretical development which allows for unequal porosity for the floor and ceiling and wall boundary pressure measurements, porosities for floor and ceiling could be deduced; (3) a scheme was developed which allowed unequal porosity of floor and ceiling and streamwise varying porosity. The boundary layer development along the perforated floor and ceiling under the influence of the model pressure field, variations in boundary layer thickness underlining the difficulties in deducing meaningful values of wall porosity were determined. Wall boundary pressure measurement, in combination with singularity modelling of the airfoil, was sufficient to yield required information on the wall interference flow without having to establish some value for wall porosity. The singularity modelling of the airfoil initially covered only lift and volume but was extended to include drag and pitching moment, and second order volume term. It is shown by asymptotic transonic small disturbance analysis, that the derived corrections to angle of attack and free stream Mach number are correct to the first order.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 231-257
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 27
    facet.materialart.
    Unbekannt
    Asymptotic methods for wind tunnel wall corrections at transonic speed (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The effort to develop classical methods to compute wall interference at transonic speeds is outlined. The two-dimensional theory and three-dimensional development are discussed. Also, some numerical application of the two-dimensional work are indicated. The basic advantages of the asymptotic theory are noted.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 193-203
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 28
    facet.materialart.
    Unbekannt
    Effect of boundary layers on solid walls in three-dimensional subsonic wind tunnels (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A solution for the tunnel wall boundary layer effects for three-dimensional subsonic tunnels is presented. The model potentials are represented with simple singularities placed on the centerline of the tunnel and Laplace's equation in cylindrical coordinates is solved for either the conventional homogeneous slotted-wall boundary condition, the solid-wall viscous boundary condition, or a combination of them. The most pronounced wall boundary layer effect is on solid blockage for completely closed wind tunnels. Boundary layers on the wall reduce the blockage from the solid-wall, no-boundary-layer case in a manner similar to opening slots in a solid wall. Additionally, for solid-wall tunnel configurations, the streamline curvature interference factor is reduced by a significant amount, whereas the lift interference factor at the model station does not depend on the boundary layer parameter. For combination wall configurations, the slot effect of the horizontal walls dominates the viscous effect of the solid sidewalls.
    Schlagwort(e): AERODYNAMICS
    Materialart: Wind Tunnel Wall Interference Assessment and Correction, 1983; p 205-218
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 29
    facet.materialart.
    Unbekannt
    Experiments suitable for wind tunnel wall interference assessment/correction (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Three experiments suitable for wall interference assessment and evaluation of proposed correction methods are presented. The experiments are: (1) a series of airfoil tests using a newly designed transonic flow facility that employs side-wall boundary layer suction and upper- and lower-wall shaping; (2) tests on a swept airfoil section spanning a solid-wall wind tunnel with fixed contouring on all four walls; and (3) tests on a swept wing of aspect ratio 3 mounted in a solid-wall wind tunnel with fixed flat walls. Each of the experiments provides data on the airfoil sections as well as on the wind tunnel walls. All the experiments were performed in solid wall wind tunnels corrected for boundary layer displacement effects. Although the experiments were performed primarily to evaluate computer code performance, it is believed that they also provide information that can be used to evaluate methods for assessing and correcting wall interference effects.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 171-190
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 30
    facet.materialart.
    Unbekannt
    Effect of upstream sidewall boundary layer removal on an airfoil test (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: Sidewall boundary layer effects were investigated by applying partial upstream sidewall boundary layer removal in the Langley 0.3-m transonic cryogenic tunnel. Over the range of sidewall boundary layer displacement thickness of these tests the influence on pressure distribution was found to be small for subcritical conditions; however, for supercritical conditions the shock position was affected by the sidewall boundary layer. For these tests (with and without boundary layer remove) comparisons with predictions of the GRUMFOIL computer code indicated that Mach number corrections due to the sidewall boundary layer improve the agreement for both subcritical and supercritical conditions. The results also show that sidewall boundary layer removal reduces the magnitude of the sidewall correction; however, a suitable correction must still be made.
    Schlagwort(e): AERODYNAMICS
    Materialart: Wind Tunnel Wall Interference Assessment and Correction, 1983; p 143-163
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 31
    facet.materialart.
    Unbekannt
    A data base for three-dimensional all-interference code evaluation (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: A validation of a measured boundary condition technique was carried out to demonstrate the feasibility of a wall interference assessment/correction (WIAC) system. An experimental evaluation was also carried out to compare performances of various techniques, to define the number of necessary boundary measurements for accurate assessment/corrections and to define the envelope of test conditions for which accurate assessment/corrections are achieved. The relative merits of a WIAC system and an adaptive wall tunnel are compared. The measurement surface boundary data is performed with a system of two rotating pipes. These pipes sweep out a cylindrical measurement surface near the tunnel walls, approximately one inch from the wall at the closest point. The experimental model was specially designed and fabricated for the adaptive wall experiments. The model is a wing/tail/body configuration with swept lifting surface. The boundary data taken in Tunnel 1T with the rotating pipe system has been shown to offer several attractive features for WIAC code evaluation. Good spatial resolution of measurements is achieved and measurements are made upstream and downstream of the model. Also, two velocity components are determined.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 101-118
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 32
    facet.materialart.
    Unbekannt
    Survey of ONERA activities on adaptive-wall applications and computation of residual corrections (1984)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: The research undertaken concerning the computation and/or reduction of wall interference follows two main axes: improvement of wall correction determinations, and use of adaptive flexible walls. The use of wall-measured data to compute interference effects is reliable when the model representation is assessed by signatures with known boundary conditions. When the computed interferences are not easily applicable to correcting the results (especially for gradients in two-dimensional cases), the flexible adaptive walls in operation in T2 are an efficient and assessed means of reducing the boundary effects to a negligible level, if the direction and speed of the flow are accurately measured on the boundary. The extension of the use of adaptive walls to three-dimensional cases may be attempted since the residual corrections are assumed to be small and are computable.
    Schlagwort(e): AERODYNAMICS
    Materialart: NASA. Langley Research Center Wind Tunnel Wall Interference Assessment and Correction, 1983; p 43-60
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 33
    facet.materialart.
    Unbekannt
    Langley high-lift research on a high-aspect-ratio supercritical wing configuration (1981)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Advan. Aerodyn.: Selected NASA Res.; p 55-77
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 34
    facet.materialart.
    Unbekannt
    Measured transonic unsteady pressures on an energy efficient transport wing with oscillating control surfaces (1981)
    In:  CASI
    Details
    Publikationsdatum: 2006-02-14
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Advan. Aerodyn.: Selected NASA Res.; p 21-36
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 35
    facet.materialart.
    Unbekannt
    Viscous transonic flow computation over Space Shuttle configuration (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: A thin-layer Navier-Stokes code capable of predicting steady-state viscous flows is applied to the transonic flow over a Space Shuttle configuration. The code is written in the generalized coordinate system, and the grid-generation code of Fujii (1983) is used for the discretization of the flow field. The flow-field computation is done using the CRAY 1S computer at NASA Ames. The computed result is physically reasonable, even though no experimental data is available for the comparison purpose.
    Schlagwort(e): AERODYNAMICS
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 36
    facet.materialart.
    Unbekannt
    Infrared mapping of galaxian centers: Star forming regions with kiloparsec scale sizes (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: A 1 to 20 micron mapping of the centers of galaxies encompassing the regions that extend out to several kiloparsecs from the nuclei is reviewed. Power emerging at or = 5 microns is a direct measure of the number of young stars present. This conclusion is strongly supported by the large-scale association of the infrared-emitting regions with visual continuum and line emission indicative of young stars, and by the similarity of the energy distributions to those of Galactic HII region/molecular cloud complexes. Much of the young-star activity is completely hidden from view. At shorter wavelengths, a variety of processes, including bremsstrahlung, are evident.
    Schlagwort(e): ASTRONOMY
    Materialart: Royal Observatory Star Formation Workshop; p 183-198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 37
    facet.materialart.
    Unbekannt
    Nonlinear aerodynamic effects on bodies in supersonic flow (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft (ISSN 0021-8669); 21; 809-815
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 38
    facet.materialart.
    Unbekannt
    The Gamma-Ray Observatory mission objectives and its significance for gamma-ray astronomy (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: The Gamma Ray Observatory (GRO) is an approved NASA mission, programmed for launch in 1988. Its complement of four detectors has established goals: (1) to study the nature of compact gamma-ray sources such as neutron stars and black holes, or objects whose nature is yet to be understood; (2) to search for evidence of nucleosynthesis especially in the regions of supernovae; (3) to study structural features and dynamical properties of the Galaxy; (4) to explore other galaxies, especially the extraordinary types such as radio, Seyferts, and quasars; and (5) to study cosmological effects by examining the diffuse radiation in detail. This paper discusses the design, objectives, and expected scientific results of each of the GRO instruments in view of the GRO mission goals.
    Schlagwort(e): ASTRONOMY
    Materialart: Advances in Space Research (ISSN 0273-1177); 3; 10-12
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 39
    facet.materialart.
    Unbekannt
    New implicit boundary procedures - Theory and applications (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Previously cited in issue 5, p. 579, Accession no. A83-16536
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal (ISSN 0001-1452); 22; 1094-110
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 40
    facet.materialart.
    Unbekannt
    Numerical simulations of unsteady transonic flow in diffusers (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Previously cited in issue 15, p. 2346, Accession no. A82-31959
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal (ISSN 0001-1452); 22; 1139-114
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 41
    facet.materialart.
    Unbekannt
    Effects of viscosity on transonic-aerodynamic and aeroelastic characteristics of oscillating airfoils (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft (ISSN 0021-8669); 21; 700-707
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 42
    facet.materialart.
    Unbekannt
    Leeside flows over delta wings at supersonic speeds (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft (ISSN 0021-8669); 21; 680-686
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 43
    facet.materialart.
    Unbekannt
    The S201 far-ultraviolet imaging survey. II - A field in Cygnus (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Far-ultraviolet imagery of a region in Cygnus, a 20 deg diameter field centered near (1950) R. A. 21 h 31.2 m decl. +37 deg 25 arcmin, was obtained by the S201 far-ultraviolet camera during the Apollo 16 mission. In a 10 minute exposure covering the 1250-1600 A wavelength range (effective wavelength 1400 A), 730 star images can be detected, corresponding to a limiting ultraviolet magnitude of about m (1400) = 10. Assuming nominal interstellar extinction values in this region near the galactic plane, this result corresponds to the detection of A0 V stars to a distance of 300 pc and of B0 V stars to 1500 pc. Uncertainties in spectral classification and interstellar extinction for individual objects are probably more significant than calibration or measurement errors. Most of the objects detected are identified with stars in the Smithsonian Astrophysical Observatory Star Catalog (1966), or the Catalog of Stellar Identifications (1979) or both, but 87 objects remain unidentified (or are identified with late-type stars).
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal Supplement Series (ISSN 0067-0049); 54; 271-290
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 44
    facet.materialart.
    Unbekannt
    Fresh attack on laminar flow (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Laminar flow control is a technology with great potential for aircraft drag reduction. Stabilization of laminar boundary layers became known as natural laminar flow (NLF) and research led to the development of NLF airfoils. Research was also conducted on stabilization by suction, referred to as laminar flow control (LFC). Experiments demonstrated that extensive laminar flow could be achieved in flight. However, there remained doubts regarding the practicality of producing, with the technology then available, wing surfaces sufficiently smooth and wavefree to meet laminar-flow criteria and maintaining the wing surface quality in normal service. In 1976, the Aircraft Energy Efficiency (ACEE) program was begun by NASA to develop fuel-conservative technology for commercial transports. The progress of the ACEE program is discussed. Attention is given to LFC wing structures, and LFC leading-edge systems.
    Schlagwort(e): AERODYNAMICS
    Materialart: Aerospace America (ISSN 0740-722X); 22; 72-76
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 45
    facet.materialart.
    Unbekannt
    Space Shuttle heating analysis with variation in angle of attack and catalycity (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Previously cited in issue 5, p. 586, Accession no. A83-16747
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Spacecraft and Rockets (ISSN 0022-4560); 21; 217-219
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 46
    facet.materialart.
    Unbekannt
    Determining asteroid masses from perturbations on Mars (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: The orbit of Mars is perturbed more than 5 m, a value compatible with the accuracy of the Viking Lander ranging data, by about three dozen asteroids. In addition to larger asteroids throughout the belt, significant perturbations of long period are generated by smaller objects near commensurabilities with Mars. The largest periodic terms induced by 1 Ceres and 2 Pallas have amplitudes of 0.8 and 0.2 km, respectively, both with 10-year periods. Due to a near commensurability, 4 Vesta causes a 5-km, 52-year term. While the Viking ranges will yield significant mass determinations for the largest three asteroids, and some of the smaller bodies should be detectable, it will be difficult to separate the smaller bodies with useful accuracies. Accurate discrimination must await range data from future missions to Mars or other bodies in the neighborhood of the asteroid belt. The Viking ranges can also yield improved masses for the outer planets (except Pluto), an application which is being exploited by groups analyzing these data. Uncertainties in the asteroid masses limit the ultimate accuracy of the Viking determinations of both the long time scale motion of the system of the inner four planets with respect to an inertial frame and the rate of change of the gravitational constant.
    Schlagwort(e): ASTRONOMY
    Materialart: Icarus (ISSN 0019-1035); 57; 1-13
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 47
    facet.materialart.
    Unbekannt
    A search for the 10-micron silicate feature in periodic Comet Grigg-Skjellerup (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: A 10-micron spectrum of periodic Comet Grigg-Skjellerup was obtained on 22 June 1982 with the UCL array spectrometer at the United Kingdom Infrared Telescope, Mauna Kea. No emission feature is obvious in the spectrum. The observed spectrum can be fit equally well by a model of small hot absorbing grains or by a composite model with less than or equal to 30 percent (3sigma) warm, 'dirty' silicate grains. The latter model is consistent with the silicate abundance in Comet Kohoutek, which did display an emission feature at 10 microns.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal (ISSN 0004-6256); 89; 170
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 48
    facet.materialart.
    Unbekannt
    Broad band X-ray astronomical spectroscopy (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: The Broad Band X-Ray Telescope (BBXRT) experiment has been designed for high sensitivity, moderate resolution spectrophotometry of cosmic sources in the range 0.5 to 12 keV. Principal elements are two co-aligned imaging telescopes with cooled Si(Li) detectors at each focus. The mirror design uses an approximate geometry of tightly nested, conical, foil reflectors that allow a large filling factor (high throughput) at small grazing angles (high energy response). Each detector consists of a cluster of five elements defined with grooves on a single crystal. This arrangement affords some spatial resolution as well as a means of substantial background reduction. Shuttle borne measurements will typically be of 2000 s duration for sources with a flux of 10 to the -12 erg/sq cm-s.
    Schlagwort(e): ASTRONOMY
    Materialart: IEEE Transactions on Nuclear Science (ISSN 0018-9499); NS-31; 786-790
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 49
    facet.materialart.
    Unbekannt
    Ultraviolet spectra of planetary nebulae. X - Physical conditions in the compact planetary nebula Sw St 1 (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Photoelectric visual and ultraviolet observations of the compact planetary nebula Sw St 1 are analyzed. The electron density, determined from the C III 1907/1909 A line ratio, is N(e) = (1.1 + or - 0.1) x 10 to the 5th/cu cm, consistent with the high emission measure and high critical frequency determined from observations of the thermal radio emission. The C/O abundance ratio in the nebula is found to be N(C)/N(O) = 0.72 + or - 0.1, i.e. the envelope is oxygen-rich, as suggested by the identification of the silicate feature in the 8-13 micron infrared spectrum. Difficulties remain in accurately determining the reddening constant to the nebula and its electron temperature.
    Schlagwort(e): ASTRONOMY
    Materialart: Royal Astronomical Society, Monthly Notices (ISSN 0035-8711); 206; 293-304
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 50
    facet.materialart.
    Unbekannt
    Radioastronomical observations of comets IRAS-Araki-Alcock (1983d) and Sugano-Saigusa-Fujikawa (1983e) (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: Continuum and spectral-line radio observations of the comets IRAS-Araki-Alcock and Sugano-Saigusa-Fujikawa obtained at a number of observatories during May and June, 1983, are compiled in tables and briefly characterized. The species NH3, H2O, CO, and HCN are considered in detail; visible-range observations of CN are compared; and the implications of the results and the experience gained in performing and coordinating the observations for the detection of important species in other comets, especially Halley's Comet, are explored.
    Schlagwort(e): ASTRONOMY
    Materialart: Icarus (ISSN 0019-1035); 60; 215-220
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 51
    facet.materialart.
    Unbekannt
    A search at the millijansky level for milli-arcsecond cores in a complete sample of radio galaxies (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: A complete sample of 26 extended radio galaxies was observed at 2.29 GHz with the Mark III VLBI system. The fringe spacing was about 3 milli-arcsec, and the detection limit was about 2 millijanskys. Half of the galaxies were found to possess milli-arcsec radio cores. In all but three sources, the nuclear flux density was less than 0.04 of the total flux density. Galaxies with high optical luminosity (less than -21.2) were more likely than less luminous galaxies to contain a detectable milliparcsec radio core (69 percent vs. 20 percent). For objects with arcsec cores, 80 percent were found to have a milli-arcsec core, even though the milli-arcsec object did not always contribute the greater part of the arcsec flux density.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 284; 519-522
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 52
    facet.materialart.
    Unbekannt
    Metric-discontinuous zonal grid calculations using the Osher scheme (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: Computations on zonal grids - in particular, grids with metric discontinuities resulting from the interspersion of highly clustered regions with coarse regions - are possible using a fully conservative form of the Osher upwind scheme. These zonal grids can result from an abrupt clustering of points near solution discontinuities or near other flow features that require improved resolution. The zonal approach is shown to capture shocks with almost 'shock-fitting' quality but with minimal effort. Results for inviscid flow, including quasi-one-dimensional nozzle flow, supersonic flow over a cylinder, and blast-wave diffraction by a ramp, are presented. These calculations demonstrate the powerful capabilities of the Osher scheme used in conjunction with zonal grids in simulating flow fields with complex shock patterns.
    Schlagwort(e): AERODYNAMICS
    Materialart: Computers and Fluids (ISSN 0045-7930); 12; 3, 19
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 53
    facet.materialart.
    Unbekannt
    New infrared observations of IRS1, IRS3, and the adjacent nebula in the OMC-2 cluster (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: Observations of the infrared cluster of low luminosity protostars in Orion Molecular Cloud 2 (OMC2) are reported. Results show that the asymmetric distribution of the extended emission seen about IRS1 is another infrared reflection nebula. Energy distributions show that the spectral shape is fairly constant throughout the nebula which indicates there is little internal extinction within this region. Integrated surface brightness values show that the nebula is 5 times brighter than IRS1 at K. Energy distributions show that IRS1 has a more pronounced ice band absorption feature at 3.1 micron; suggesting that there is more extinction along the direct line of sight to IRS1 than along a line from IRS1 to the scattering grains and then to the observer. The distribution of the extended emission around IRS1 is similar to the reflection nebula seen in NGC 7538 (Werner et al. 1979). The asymmetric shapes of the two nebulae are similar and in each case there is excess extinction along line of sight to the illuminating source.
    Schlagwort(e): ASTRONOMY
    Materialart: Royal Observatory Lab. and Observational Infrared Spectra of Interstellar Dust; p 162-166
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 54
    facet.materialart.
    Unbekannt
    Lifting surface theory for a helicopter rotor in forward flight (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: A lifting surface theory was developed for a helicopter rotor in forward flight for compressible and incompressible flow. The method utilizes the concept of the linearized acceleration potential and makes use of the vortex lattice procedure. Calculations demonstrating the application of the method are given in terms of the lift distribution on a single rotor, a two-bladed rotor, and a rotor with swept-forward and swept-back tips. In addition, the lift on a rotor which is vibrating in a pitching mode at 4/rev is given. Compressibility effects and interference effects for a two-bladed rotor are discussed.
    Schlagwort(e): AERODYNAMICS
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 55
    facet.materialart.
    Unbekannt
    Transient dips of Cygnus X-1 observed from Tenma (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: The transient intensity dips of the binary system Cyg X-1 have been observed, using the gas scintillation proportional counter (GSPC) array onboard the Tenma X-ray astronomy satellite. The duration of the dips was in the range from several seconds to 10 minutes, with several dips occurring as much as 15 h before the superior conjunction. Within the dips, complex structures were observed with time scales of several seconds, and, in at least one case, shorter than two seconds. For a dip lasting longer than 10 minutes, a high-quality spectrum was obtained which reveals the K-absorption edge of iron at 7.18 + or - 0.18 keV. On the basis of the observed absorption, it is suggested that the dips are caused by absorption due to relatively cool matter (less than about 30,000 k); the low-energy excess observed during the dips is due either to an extended soft X-ray emitting corona or to partial obscuration of the X-ray source by multiple blobs. From the time structure of the dip, a blob size of the order of 10 to the 9th cm is derived.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of Japan, Publications (ISSN 0004-6264); 36; 4, 19
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 56
    facet.materialart.
    Unbekannt
    IUE observations of the 'Butterfly' Nebula M2-9 (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: IUE observations of the peculiar 'Butterfy' nebula M2-9 indicate that it is not a normal planetary nebula. The ultraviolet spectrum is characterized by few emission lines and a weak continuum. Mg II 2800 A is the strongest emission line present and may be indicative of a binary nucleus. Lines of N v, Q I, N III, N IV, Si III, and C III are seen, but C IV and O III are conspicuous by their absence. T(e) = 10,250 + or - 400 K was determined for the core. Nitrogen in the core is found to be overabundant by about a factor of 5 over the solar value. M2-9 may be an object in the early stages of becoming a planetary nebula.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal, Part 1 (ISSN 0004-637X); 287; 353-358
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 57
    facet.materialart.
    Unbekannt
    Cometary showers and unseen solar companions (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: The possibility that an invisible solar companion passing through the Oort cloud every 28 Myr precipitates a sufficiently high rate of cometary collisions with the earth to account for periodic mass species extinctions recorded in the fossil record is discussed. A Monte Carlo simulation shows that any hypothesized 'death star' with a 28 Myr orbit would experience an average 10 percent change in period per orbit. Production of an 18-fold increase in cometary impacts would be associated with a 0.055 probability that a 10 km nucleus would hit the earth in a shower once every 510 Myr, longer than the proposed extinction periodicity. However, if the death star orbit has a 0.6 eccentricity and the Oort cloud is sufficiently densely populated, a 2 billion comet shower may be possible. A survey of large terrestrial impact craters indicates that 6-12 craters with diameters over 10 km originated in periodic showers. The extinctions in any case occur at 26 Myr periods and cannot be correlated with the 33 Myr period of recrossing the galactic plane, or with any other known phenomena.
    Schlagwort(e): ASTRONOMY
    Materialart: Nature (ISSN 0028-0836); 312; 380; Rep
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 58
    facet.materialart.
    Unbekannt
    Analysis of surface pressure distributions on two elliptic missile bodies (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Spacecraft and Rockets (ISSN 0022-4650); 21; 528-533
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 59
    facet.materialart.
    Unbekannt
    Evidence for material between Saturn's A and F rings from the Voyager 2 photopolarimeter experiment (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: The region in the Saturn system between the F ring and the outer edge of the A ring is an area that appears, in images from the imaging experiment, to be virtually devoid of material except for three small satellites. Near the orbit of 1980S28, Atlas - the innermost satellite - the Voyager Photopolarimeter Stellar Occultation data show a discontinuity in count rate which marks a boundary between the tenuous material near the outer edge of the A ring and the orbit of Atlas. The data pertaining to this region have been examined with the aid of statistics and models generated from other similar ring structures. It is concluded that the discontinuity is real, implying the existence of tenuous material of normal optical depth of 0.01 to 0.006 in this region.
    Schlagwort(e): ASTRONOMY
    Materialart: Icarus (ISSN 0019-1035); 60; 409-415
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 60
    facet.materialart.
    Unbekannt
    1984 AB - A unique Mars-crossing asteroid (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: Asteroid 1984 AB, discovered in January 1984, proved to be a unique object with a close dynamical relationship to Mars. A brief history of the discovery and subsequent 'evolution' of the orbit as it was refined is presented. The preliminary orbit of 1984 AB indicated that it might be a Mars Trojan, and an extended discussion of this interesting possibility is presented, but this hypothesis had to be dismissed after further observations had refined the orbit. The semimajor axis and orbital eccentricity are very similar to that of Mars. No other known Mars-crossing asteroid exists with an orbit as closely associated to Mars.
    Schlagwort(e): ASTRONOMY
    Materialart: Icarus (ISSN 0019-1035); 60; 404-408
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 61
    facet.materialart.
    Unbekannt
    A general perturbation approach for computational fluid dynamics (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal (ISSN 0001-1452); 22; 1748-175
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 62
    facet.materialart.
    Unbekannt
    A radar study of Comet IRAS-Araki-Alcock 1983d (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: Radar echoes from Comet IRAS-Araki-Alcock at wavelengths 3.54 and 12.9 cm indicate that the comet's nucleus is very rough on a scale larger than the radar wavelengths; however, the low polarization ratio (25 percent at 3.54 cm) indicates that the scattering is not dominated by multiple reflections, internal reflections, or large abundances of sharp edges, cracks, and pits. The shape of the nucleus probably departs greatly from a sphere with average radii near 3-4 km. The nucleus does not appear to look significantly different from a number of Apollo and Amor asteroids except that: (1) there is a suggestion that minor structure moves rapidly across the spectra, and (2) the debris not gravitationally bound to the comet was detected, and contributes 25 percent of the total radar cross section at the 12.9-cm wavelength. Other considerations suggest that the pole was at least 45 deg away from the line of sight on two days of observation, and that the rotation period is approximately 1-2 days.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal (ISSN 0004-6256); 89; 1745-175
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 63
    facet.materialart.
    Unbekannt
    A solar spectral line list between 10 and 200 A modified for application to high spectral resolution X-ray astronomy (1984)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-19
    Beschreibung: A spectral line list for the 10-200 A range is developed from existing solar spectra for application to high spectral resolution measurements of astrophysical plasmas. The solar spectral line lists are merged into a single comprehensive list. The effect of the solar emission measure distribution is removed from the line intensities, which results in a set of emission rates for the lines that can be applied to many optically thin, low density high temperature plasmas in ionization equilibrium. In addition to the measured solar lines, 250 theoretical lines are added to this list. These lines fall in wavelength regions where the existing solar lists have few lines because of limitations in instrumental sensitivity. Also, some lines have been added because the sun has very little plasma at temperatures of about one million K, and consequently these lines are weak or absent in solar spectra. The entire list contains about 600 lines. Finally, predicted spectra of the two RS CVn stars, alpha Aur (Capella) and UX Ari, are presented at 1 and 0.25 A spectral resolution. Also, the solar spectrum is shown at 1 A resolution, and the emission rate spectrum (spectrum not modified by an emission measure distribution) is shown at very high spectral resolution. The predicted spectra for Capella and UX Ari are based on results obtained from the Einstein and International Ultraviolet Explorer (IUE) spacecraft.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal Supplement Series (ISSN 0067-0049); 56; 67-89
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 64
    facet.materialart.
    Unbekannt
    Comets (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 65
    facet.materialart.
    Unbekannt
    Electron densities for 10 planetary nebulae derived from the semiforbidden C III lambda 1907/1909 ratio. II (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 66
    facet.materialart.
    Unbekannt
    Medium energy gamma ray astronomy with transpacific balloon flights (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 67
    facet.materialart.
    Unbekannt
    Studies in astronomical time series analysis. I - Modeling random processes in the time domain (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal Supplement Series; 45; Jan. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 68
    facet.materialart.
    Unbekannt
    Three new 'nonterrestrial' molecules (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 69
    facet.materialart.
    Unbekannt
    Discovery of phase-locked variable polarization in an RS Canum Venaticorum-like star, HR 5110 (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 70
    facet.materialart.
    Unbekannt
    Vortex-flow aerodynamics - An emerging design capability (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Astronautics and Aeronautics; 19; May 1981
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 71
    facet.materialart.
    Unbekannt
    The 45 micron H2O ice band in the Kleinmann-Low Nebula (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 245
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 72
    facet.materialart.
    Unbekannt
    Longitudinal grooves for bluff body drag reduction (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 19; Apr. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 73
    facet.materialart.
    Unbekannt
    Concerning the Wolf-Rayet and other luminous early-type stars (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 244
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 74
    facet.materialart.
    Unbekannt
    Observation of the core of the Perseus cluster with the Einstein solid state spectrometer - Cooling gas and elemental abundances (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 244
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 75
    facet.materialart.
    Unbekannt
    Non-linear stability around the triangular libration points (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Celestial Mechanics; 23; Mar. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 76
    facet.materialart.
    Unbekannt
    High-resolution observations of the QSO 3C 345 at 1.3 centimeters (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 243
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 77
    facet.materialart.
    Unbekannt
    Vectored injection into compressible laminar and turbulent boundary layers (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Computer Methods in Applied Mechanics and Engineering; 25; Jan. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 78
    facet.materialart.
    Unbekannt
    Report of the panel on theoretical aerodynamics (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: High Reynolds Number Res. - 1980; p 277-286
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 79
    facet.materialart.
    Unbekannt
    High Reynolds number research requirements for space vehicle design (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: High Reynolds Number Res. - 1980; p 265-274
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 80
    facet.materialart.
    Unbekannt
    Report of the panel on aeroelasticity and unsteady aerodynamics (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: High Reynolds Number Res. - 1980; p 237-246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 81
    facet.materialart.
    Unbekannt
    Model experience in the Langley 0.3-m transonic cryogenic tunnel (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: High Reynolds Number Res. - 1980; p 53-73
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 82
    facet.materialart.
    Unbekannt
    Radio astronomy (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: The Telecommun. and Data Acquisition Rept.; p 1-2
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 83
    facet.materialart.
    Unbekannt
    High-resolution IUE observations of the 1981 eclipse of 32 CYG (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Smithsonian Astrophysics Observatory 2nd Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Vol. 1; p 245-259
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 84
    facet.materialart.
    Unbekannt
    Optical photometry of SS 433 - 200 nights of data 1979-1980 (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 85
    facet.materialart.
    Unbekannt
    Infrared photometry of comets Bowell and P/Stephan-Oterma (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 86
    facet.materialart.
    Unbekannt
    X-ray and VLBI radio observations of the quasars NRAO 140 and NRAO 530 (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 249
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 87
    facet.materialart.
    Unbekannt
    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
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 88
    facet.materialart.
    Unbekannt
    Two-component X-ray emission from RS Canum Venaticorum binaries (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 246
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 89
    facet.materialart.
    Unbekannt
    Pulsar gamma-rays - Spectra, luminosities, and efficiencies (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 245
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 90
    facet.materialart.
    Unbekannt
    The Uranus occultation of 10 June 1979. I - The rings (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Journal; 86; Apr. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 91
    facet.materialart.
    Unbekannt
    Infrared observations of AE Aquarii (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 93
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 92
    facet.materialart.
    Unbekannt
    Effectiveness of leading-edge vortex flaps on 60 and 75 degree delta wings (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: Journal of Aircraft; 18; Apr. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 93
    facet.materialart.
    Unbekannt
    An X-ray survey of nine historical novae (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 244
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 94
    facet.materialart.
    Unbekannt
    Pulsar and diffuse contributions to observed galactic gamma radiation (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Nature; 290; Mar. 26
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 95
    facet.materialart.
    Unbekannt
    Variable X-ray spectra of BL Lacertae objects - HEAO 1 observations of PKS 0548 - 322 and 2A 1219 + 305 (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Schlagwort(e): ASTRONOMY
    Materialart: Astrophysical Journal; vol. 243
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 96
    facet.materialart.
    Unbekannt
    Phase-correlated P Cygni profile variations of the C III multiplet in UW Canis Majoris (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomy and Astrophysics; 94; 2, Fe; Feb. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 97
    facet.materialart.
    Unbekannt
    Partially confined multiple jet mixing (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 19; Mar. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 98
    facet.materialart.
    Unbekannt
    Unsteady Newton-Busemann flow theory. I - Airfoils (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 19; Mar. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 99
    facet.materialart.
    Unbekannt
    Evidence of imbedded vortices in a three-dimensional shear flow (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): AERODYNAMICS
    Materialart: AIAA Journal; 19; Mar. 198
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
  • 100
    facet.materialart.
    Unbekannt
    VRI photometry of selected SAO stars (1981)
    In:  Other Sources
    Details
    Publikationsdatum: 2011-08-18
    Beschreibung: 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.
    Schlagwort(e): ASTRONOMY
    Materialart: Astronomical Society of the Pacific; vol. 92
    Format: text
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    NASA TECHNICAL REPORTS
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...