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  • 1
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: As a part of the EET aerodynamics program an out-of-house program was developed and monitored to provide theoretical procedures useful in the design of transport aircraft. The focus of the effort was to provide tools valid in the nonlinear transonic speed range. The effort was divided into two basic areas, inviscid configuration analysis and design procedures and viscous correction procedures.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Advan. Aerodyn.: Selected NASA Res.; p 79-94
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  • 2
    Publikationsdatum: 2006-02-14
    Beschreibung: Improvements in cruise efficiency on the order of 15 to 40% are obtained by increasing the extent of laminar flow over lifting surfaces. Two methods of achieving laminar flow are being considered, natural laminar flow and laminar flow control. Natural laminar flow (NLF) relies primarily on airfoil shape while laminar flow control involves boundary layer suction or blowing with mechanical devices. The extent of natural laminar flow that could be achieved with consistency in a real flight environment at chord Reynolds numbers in the range of 30 x 10(6) power was evaluated. Nineteen flights were conducted on the F-111 TACT airplane having a NLF airfoil glove section. The section consists of a supercritical airfoil providing favorable pressure gradients over extensive portions of the upper and lower surfaces of the wing. Boundary layer measurements were obtained over a range of wing leading edge sweep angles at Mach numbers from 0.80 to 0.85. Data were obtained for natural transition and for a range of forced transition locations over the test airfoil.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Advan. Aerodyn.: Selected NASA Res.; p 11-20
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  • 3
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    In:  CASI
    Publikationsdatum: 2006-06-04
    Beschreibung: The active cavity radiometer (ACR) experiment on the Spacelab 1 mission to measure the total solar irradiance is discussed. Short and long term variations in the total solar output of optical energy are studied. Solar total irradiance observation provides information on the solar cycle and other long term trends in solar output that are of climatological significance as well as short term solar physics phenomena. The interaction of solar radiation with the Earth's atmosphere, oceans, and land masses provides the primary driving forces for the formation of weather systems and the determination of climate. Astrophysical measurements determine the total energy flux. The principal role of the ACR observations support extended solar irradiance experiments on free flying satellites. Solar irradiance measurements are important in the establishment of the radiation scale at the solar total flux level in the international system of units (SI).
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 4 p
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  • 4
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    In:  CASI
    Publikationsdatum: 2006-06-04
    Beschreibung: The study of galactic and faint extragalactic extended sources and peculiar ultraviolet objects by a very wide field of view camera, operated in the ultraviolet photometric and spectrometric modes is discussed. The photometric mode is direct photography through filters for observation of the following sources: (1) large scale distribution of ultraviolet radiation in the Milky Way; (2) diffusion of the galactic light above the galactic plane and in front of the large absorbing clouds; (3) the optical emission of the interstellar matter; (4) stars, and starlike objects with diameters less than 3 arc minutes. In the spectrometric mode (nebular spectrograph) the light from the center of the photometric field is concentrated on a slit covering 10 degrees by 10 arc minutes on the sky.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 5
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    In:  CASI
    Publikationsdatum: 2006-06-05
    Beschreibung: The use of a personal miniature electrophysiological tape recorder to measure the physiological reactions of space flight personnel to space flight stress and weightlessness is described. The Oxford Instruments Medilog recorder, a battery-powered, four-channel cassette tape recorder with 24 hour endurance is carried on the person and will record EKG, EOG, EEG, and timing and event markers. The data will give information about heart rate and morphology changes, and document adaptation to zero gravity on the part of subjects who, unlike highly trained astronauts, are more representative of the normal population than were the subjects of previous space flight studies.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 2 p
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  • 6
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    In:  CASI
    Publikationsdatum: 2006-06-04
    Beschreibung: A test of the mapping capabilities of high resolution space photography taken at the resolution limit of image motion on large film format is planned. The metric camera system and its planned operation are described.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 4 p
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  • 7
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    In:  CASI
    Publikationsdatum: 2006-06-04
    Beschreibung: Photography and measurement of cloud-like structures of bright parallel bands observed in near infrared photography of the night sky is planned. The instrument is described and the purpose of the experiment summarized.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 2 p
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  • 8
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    In:  CASI
    Publikationsdatum: 2006-06-04
    Beschreibung: High resolution infrared spectroscopic observations of the Earth's limb in the wavelength range characteristic of the vibrational-rotational lines of trace atmospheric constituents is planned. The instrument and its operation and the purpose of the experiments are summarized.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center Spacelab Mission 1 Expt. Descriptions; 3 p
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  • 9
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The counter is a static thermal diffusion chamber which has been modified to include an optical system for the determination of droplet concentration by the measurement of scattered light. The determination of concentration is made by measurement of the peak scattered light signal from the cloud of growing droplets which is a function of both the droplet concentration and chamber supersaturation. Because the formation of the peak is related to the rate of growth of the droplets and sedimentation, both of which are determined by supersaturation, the system calibration can be uniquely determined by comparison with an absolute counter such as a static diffusion chamber with a photographic recording system.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 40-41
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  • 10
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: Unlike typical CCN counters, this device counts the numbers of water droplets condensed on aerosol particles sampled on a microcover glass at various different relative humidities. The relative humidities ranged from 75 percent to a calculated value of 110 percent. A schematic of the apparatus is shown. The individual CCN can be identified in an optical micrograph and scanning electron micrograph and may be inspected for their chemical composition later.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 35-36
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  • 11
    Publikationsdatum: 2006-02-14
    Beschreibung: In performing the data analysis of the measurements achieved during the Workshop with the device, a global approach was preferred rather than an individual analysis, in order to illustrate some main characteristics in the behavior of the device with respect to a mean behavior resulting from a general survey of all the equipments involved in each experiment. The device tends generally to overestimate the CCN concentrations measured near the high supersaturations and sometimes underestimates the concentrations close to 0.1% or 0.2% of supersaturation. Despite the fact that it belongs to a type of static diffusion chamber, it shows, however, similar spectra to those obtained with other types of chambers (continuous flow diffusion chamber and haze chamber).
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 17-19
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  • 12
    Publikationsdatum: 2006-02-14
    Beschreibung: The group's CCN counter is described. It is a static, horizontal, parallel plate thermal gradient diffusion chamber. Examples of the application of the CCN are presented and include the CCN spectra measured during the winter of 1978-79 near Elk Mountain, Wyoming. Comparisons of droplet concentrations derived from upwind CCN spectra are covered.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 11-13
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  • 13
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: A summary on heavy rain effects on aircraft aerodynamics validation of research and some wind shear accidents in which heavy rain were an important factor. Frost formation and what frost does to the lift and drag curves for an airfoil was examined. If frost could cause severe aerodynamic problems for both general aviation and transport aircraft due to its roughness, then heavy rain produce a similar result. The influencing parameters of heavy rain on an aircraft are studied. Sources of aerodynamic roughness due to rain and wind shear and heavy rain accidents are outlined.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems 76-80 (SEE N82-21139 12-01)
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  • 14
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: Meteorology impact on future aircraft design is discussed. Upcoming changes in both design and operations that will be influenced by the meteorological environment are outlined. Future and more nonconventional designs and meteorological impact brought about by operational changes over the next few years are examined.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 29-34
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  • 15
    Publikationsdatum: 2006-02-14
    Beschreibung: The size distribution was measured in the size range between 0.0057 and 0.57 micrometer radius. A description of the instrumentation and data analysis is given, together with the measured size distributions calculated for 23 experiments.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 69-78
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  • 16
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The experiments performed at the Workshop were undertaken to confirm the calculated sample volume, determine the usable range of supersaturation, and minimum detectable size. Comparison of absolute CCN concentrations with other state-of-the-art continuous flow diffusion chambers at supersaturations near 1 percent indicated that the volume used produced CCN concentrations well within the range of CCN concentrations determined at the workshop. This agreement is interpreted to mean the sample volume was correct. Direct measurements of the beam geometry done in the laboratory indicated a factor of 4-5 error. This error is apparently due to the larger apparent visible beam diameter versus the actual usable beam diameter given the droplet illumination, chamber optical geometry, microscope optics and film characteristics.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 44-45
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  • 17
    Publikationsdatum: 2006-01-16
    Beschreibung: A multi-channel chopper system designed and built to stringent specifications is providing an excellent performance for a total ozone mapping spectrometer (TOMS). State of the art machining technology, suitable material selection, and a way to hold and position the slit plate resulted in the instrument's better than expected performance. A shutter method used for internal calibration allows compensation for the occurrence of an unlikely wavelength shift during testing, launch, or during the orbiting life of the instrument. The TOMS is part of a payload on Nimbus 7 launched on October 24, 1978.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Marshall Space Flight Center The 15th aerospace Mech. Symp.; p 63-75
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  • 18
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: In the IHC the critical supersaturation is inferred from the measurement of the size of particles which have grown to their equilibrium size at exactly 100 percent RH. The largest size channel corresponds to a critical supersaturation of 0.014 percent. The growth time required for particles of this size to reach their equilibrium size exceeds the 110 second residence time in the IHC. Since the supersaturation spectrum is always very steep in this region, the contribution of these larger particles which have not yet attained their equilibrium size to smaller size channels is negligible. However, failure of these particles to reach their equilibrium size could result in a significant lowering of the count in the size channel corresponding to the smaller critical supersaturation.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 42-43
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  • 19
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The chamber geometry and optical arrangement are described. The supersaturation range is given and consists of readings taken at five fixed points: 0.25%, 0.5%, 0.75%, 1.0%, and 1.25%. The detection system is described including light source, cameras, and photocell detectors. The temperature control and the calibration of the chamber are discussed.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 26-27
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  • 20
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The NRL thermal gradient diffusion cloud chamber (TGDCC) consists of two plates 7.5 cm in diameter separated by 1.25 cm and covered with saturated filter paper. The cylindrical wall separating the plates is glass. The top plate is at room temperature and the bottom plate is cooled with a thermoelectric cooler. The temperature difference is measured with several sets of thermocouples. The CCN concentration was determined from the video recording. This procedure of averaging the maximum count obtained on several successive recordings at the same supersaturation results in concentrations which are somewhat higher than concentrations calculated from an average across the plateau.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 14-16
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  • 21
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The connection between fuel consumption and weather data is discussed. Fuel efficient flights creating adequate near real time weather information are examined. The lack of highly resolved real time and near real time wind and temperature data at flight altitudes is investigated. The existing systems, which is based on twice a day balloon observations, supplemented by pilot reports or other occasional data, is not adequate for optimum flight planning. The impacts of upper winds and temperatures on fuel efficiency and flight planning are not widely appreciated and developing new weather products are considered.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Marshall Space Flight Center Proc.: 5th Ann. Workshop on Meteorol. and Environ. Inputs to Aviation Systems; p 15-19
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  • 22
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: Two instruments were used to size dry aerosols for the CCN experiments: the Naval Research Laboratory (NRL) instrument which uses an electrical mobility analyzer to separate the aerosol size fractions and a diffusion chamber to grow and count the particles and the University of Wyoming (WYO) aerosol monitoring system. Measurements from these two systems were usually found to be in agreement during the CCN Workshop. Two examples are presented to compare aerosol size distribution measurements of the two instruments: experiment 8 (monodisperse NaCl) and experiment 27 (polydisperse AgI). Differential (dN/dR) and cumulative plots are shown for both instruments for experiment 8 and experiment 27; also shown are Aitken particle measurements for comparison.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 106-107
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  • 23
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: Nine CCN counters of the static diffusion (SDC) type were compared with one another and with continuous flow diffusion (CFD) chambers. The nine SDCs showed a considerable amount of variation, largely attributable to newness and/or lack of prior calibration of some units. The five more consistent instruments agreed quite well, to within at least 20 percent of the NRL mobility analyzer and to within 10 percent at 1 percent supersaturation. There was satisfactory agreement between the more reliable SDC and CFD chambers.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 57-63
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  • 24
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The diffusion tube was designed to operate below about 0.25 percent of water supersaturation. It is simply a long tube lined on the inside with a damp chamois cloth, and heated isothermally to a few degrees centigrade above the incoming air. The diffusion coefficient for water vapor is slightly larger than that for heat, making it possible to supersaturate the airflow. This is the same principle by which transient supersaturations may occur in parallel plate cloud chambers. Only the diffusion of vapor and heat from the walls into the moving air are considered.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 37-39
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  • 25
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    In:  CASI
    Publikationsdatum: 2006-02-14
    Beschreibung: The chamber is a thermal gradient diffusion type with the upper plate at room temperature and the lower plate thermoelectrically cooled. The light from a 25W projector bulb is focused in a beam of approximations 1x3 mm in the central part of the chamber. The light scattered by drops is viewed in the forward direction (40 deg) by a microscope and a sensitive photodetector. Experiments were performed to relate the peak output from the photocell with the maximum number of drops in the beam recorded photographically. The microscope is used to check the calibration at low concentrations of CCN. The results of the experiments and the performance of the counter are reported.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Desert Research Inst. The Third Intern. Cloud Condensation Nuclei Workshop; p 33-34
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  • 26
    Publikationsdatum: 2011-08-18
    Beschreibung: A low-power portable data acquisition system presently in use for geomagnetic measurements is described. The system is composed of a data-processing system containing a low-power microprocessor, a 9-track digital tape recorder, and a rechargeable battery pack. The magnetometer is a low-power three axis fluxgate design. Under program control the data processing system keeps track of time of day and date, samples three analog magnetometer outputs at intervals of either 0.4 or 2 s, digitizes the data to 15-bit resolution, and, depending upon relative magnetic activity, decides upon data compression to increase the tape storage capacity. It also monitors and records internal voltages and provides self-checking functions which may be monitored through a visual readout on the control panel. The system is mounted in a rugged, weather-tight carrying case suitable for use outdoors with minimal protection. The system, including magnetometer, uses 1.6-W power and can store 5.7 Mbytes of data.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: IEEE Transactions on Geoscience and Remote Sensing; GE-19; July 198
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  • 27
    Publikationsdatum: 2011-08-18
    Beschreibung: Advances in instrumentation for use in nuclear-science studies are described. Consideration is given to medical instrumentation, computerized fluoroscopy, environmental instrumentation, data acquisition techniques, semiconductor detectors, microchannel plates and photomultiplier tubes, reactor instrumentation, neutron detectors and proportional counters, and space instrumentation.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
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  • 28
    Publikationsdatum: 2011-08-18
    Beschreibung: Experiments have been done to study the performance of mercuric iodide (HgI2) detectors in the ultralow-energy X-ray region. Energy resolution values of 245 eV (FWHM) for the Mg K-alpha X-ray line at 1.25 keV and 225 eV (FWHM) for the electronic noise linewidth have been obtained for an HgI2 detector with painted carbon contacts using a pulsed-light feedback preamplifier; the whole system was operated at room temperature. The resolution values in the ultralow-energy region are still limited by electronic noise of the system. In an attempt to minimize X-ray attenuation in the front contact, detectors were prepared with thin evaporated Pd contacts. These detectors show a pronounced low-energy tailing of the photopeak below a few keV, in contrast to the spectra obtained by detectors with carbon contact. An attempt has been made to explain the tailing effect starting with models wich have been proposed to describe similar effects in Ge detectors.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
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  • 29
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    In:  Other Sources
    Publikationsdatum: 2011-08-18
    Beschreibung: The assumption that spherical-shell ion chamber rssponse is equal to the dose in the center of the cavity is found to be a poor approximation for ion chambers used for area monitoring in the space program. The dose response is calculated using the appropriate areal density distribution function. Effects of nuclear reaction are evaluated using proton buildup factors. Errors of up to 100% are found for some components of the space radiation environments.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Nuclear Technology; 52; 1, Ja; Jan. 198
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  • 30
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    Publikationsdatum: 2011-08-18
    Beschreibung: The use and modifications of the T-38 aircraft as chase planes for the STS-1 landing are discussed. Two planes tracked the approach at Edwards AFB, with the lead plane responsible for airspeed and altimetry calibration, technical photography, landing gear status, and height-above-touchdown calls; the second T-38 provided live TV and back-up. Modifications included extension of the landing gear extension speed, increasing the area of the speedbrakes, and installation of a TV system; the goal was to stay with the Shuttle below 40,000 ft while it descended at 15,000 ft/min. Ten T-38's were modified and the deployment of lead and back-up crews during the first Shuttle flight is outlined. Western Test Range C-band radar data of the Orbiter position were transformed into intercept coordinates and VHF relayed to the chase craft. Photographs were taken of the right and left sides and underside of the Shuttle while flying with the speedbrake up to match the Shuttle speed.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 31
    Publikationsdatum: 2011-08-18
    Beschreibung: The development of a comprehensive analytical model of rotorcraft aerodynamics and dynamics is described. Particular emphasis is given to describing the reasons behind the choices and decisions involved in constructing the model. The analysis is designed to calculate rotor performance, loads and noise; helicopter vibration and gust response; flight dynamics and handling qualities; and system aeroelastic stability. It is intended for use in the design, testing and evaluation of a wide class of rotors and rotorcraft and to be the basis for further development of rotary wing theories. The general characteristics of the geometric, structural, inertial and aerodynamic models used for the rotorcraft components are described, including the assumptions introduced by the chosen models and the resulting capabilities and limitations. Finally, some examples from recent applications of the analysis are given.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Vertica; 5; 3, 19; 1981
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  • 32
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    Publikationsdatum: 2011-08-18
    Beschreibung: A method is described of applying a variable frequency-shift to a laser beam, by means of Bragg cells, in which the direction of the output diffracted beam is unaffected by the magnitude of the applied shift. Applications of the technique to reference-beam and Doppler-difference forms of laser anemometry are discussed together with methods of obtaining increased dynamic range.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; Feb. 15
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  • 33
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    Publikationsdatum: 2011-08-18
    Beschreibung: Fluorescence lidar when applicable offers one of the most sensitive methods for measuring the concentration of trace constituents of the atmosphere. In the conduct of a fluorescence lidar experiment, a number of parameters which can be used to optimize the SNR can be controlled. In this paper the optimum division of laser pulses centered on and off the fluorescence excitation wavelength is calculated as a function of the ratio of the fluorescence signal strength to the strength of fluorescence from interfering species. For strong interference signals the time should be divided equally on and off the line. For strong fluorescence signals the time on line is proportional to the square root of the on-line off-line signal ratio. The optimization of the integration time for varying values of signal-to-background and signal-to-interference ratios, atmospheric attenuation, laser energy variations, background measurement time, and on-line off-line time division is also considered.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; Feb. 15
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  • 34
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    Publikationsdatum: 2011-08-18
    Beschreibung: The use of laser Raman measurement techniques in remote sensing applications is surveyed. A feasibility index is defined as a means to characterize the practicality of a given remote Raman measurement application. Specific applications of Raman scattering to the measurement of atmospheric water vapor profiles, methane plumes from liquid natural gas spills, and subsurface ocean temperature profiles are described. This paper will survey the use of laser Raman measurement techniques in remote sensing applications using as examples specific systems that the Computer Genetics Corporation (CGC) group has developed and engineered.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Optical Engineering; 20; Jan
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  • 35
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    Publikationsdatum: 2011-08-18
    Beschreibung: Action to be taken to prepare to implement efficient, modern commuter aircraft for the 1990s is outlined. The increase in the contribution of jet fuel costs to aircraft direct operating costs (DOC) is noted as the motivation for the introduction of turboprop-powered commuter aircraft, which use 15-20% less fuel per seat mile at short stage lengths, to replace larger jet transports. Designs proposed by various manufacturers which will make use of existing technology for 19-, 30- and 50-seat aircraft capable of carrying a full payload of passengers and baggage for 600 n mi and optimized for minimum DOC over a 100-n mi stage length are presented, and the improvements in fuel usage, DOC and passenger comfort to be obtained with the use of advanced technology are pointed out. The goals and considered technologies of the dedicated small-transport aircraft technology program recommended by a commuter air transport subcommittee of the NASA Advisory Council Aeronautics Advisory Committee to speed the development of commuter technology are then presented, with attention given to efforts of analysis, design and testing of propulsion systems, structures, aerodynamics and systems intended to result in 16-24% savings in DOC and up to 40% savings in fuel. The commuter development plans of various manufacturers are also indicated.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Astronautics and Aeronautics; 19; Feb. 198
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  • 36
    Publikationsdatum: 2011-08-18
    Beschreibung: It is proposed to use high-resolution stimulated Raman spectroscopy to directly measure high-speed molecular flow velocities in wind tunnels and in combustive chambers. A feasibility study indicates that flow speeds from Mach 0.04 up may be measured with the proposed method using available laser systems. It is pointed out that the success of the proposed technique will make it possible to measure all interesting flow parameters, i.e., species concentration, temperature, and velocity, in a time of less than 1 microsecond at a repetition rate of 10,000/s using a single experimental arrangement.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: IEEE Journal of Quantum Electronics; QE-17; Jan. 198
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  • 37
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    Publikationsdatum: 2011-08-18
    Beschreibung: The distribution of image energy by the central obstruction of annular apertures is discussed with special emphasis on the effect of an aperture shape parameter which can be interpreted optically as the inverse obstruction ratio. This parameter generates group arrangements with the number of rings given by N2 = 1/a, where a is the central obstruction ratio.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; Jan. 15
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  • 38
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    Publikationsdatum: 2011-08-18
    Beschreibung: The construction, tests, and performance of a temperature stabilized phase detector are discussed. It has a frequency stability of 5 parts in 10 to the 16th power at 100 MHz, with a temperature step of 20 C (15 to 35 C).
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: The Telecommun. and Data Acquisition Progr. Rept. 42-64; p 90-95
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  • 39
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    Publikationsdatum: 2011-08-18
    Beschreibung: Electrical path delay caused by atmospheric water vapor may be a limiting error source for geodetic measurements made with VLBI. Direct measurement of atmospheric water vapor is necessary to obtain path delay correction required by the ORION project. A dual channel water vapor radiometer is described which operates at frequencies near the 22 GHz water vapor line and is capable of collecting data that permits calculation of path delay within 2 cm accuracy.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Telecommun. and Data Acquisition; p 10-14
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  • 40
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    Publikationsdatum: 2011-08-18
    Beschreibung: The aerodynamic characteristics which affect the fuel consumption of general aviation aircraft are outlined. All data are presented in the form of graphs.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Joint Univ. Program for Air Transportation Res., 1980; p 133-142
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  • 41
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    Publikationsdatum: 2011-08-18
    Beschreibung: A new type of apparatus for high-pressure experiments at low temperature (1.5 K) is presented. It uses a flat diamond anvil with a spherical indentor. It utilizes a load ring placed under the sample, so that the load (and hence pressure) can be measured in situ at low temperature. The apparatus was successfully used to investigate the high-conductivity state of sulphur. It can be used to investigate other thin film samples.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; Feb. 198
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  • 42
    Publikationsdatum: 2011-08-18
    Beschreibung: A system to be used for the tracking of high altitude chemical releases in the presence of a bright daytime sky is described. The system uses telecentric optics, a tilting filter, a solid state image sensor, and a real time digital processor to produce the release image. Field test data are presented.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; Mar. 15
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  • 43
    Publikationsdatum: 2011-08-18
    Beschreibung: An automated methane/total hydrocarbon analyzer is presented, which can produce alternate methane/total hydrocarbon measurements every 7 seconds to provide the spatial resolution required for regional hydrocarbon measurements at aircraft speeds. The construction and sampling techniques developed for the aircraft mounted system are discussed. A technique to periodically measure atmosphere oxygen is incorporated into the analyzer to ensure accurate hydrocarbon measurements, and a data collection methodology is developed to minimize errors resulting from changes in flame ionization detector sensitivity at different altitudes. Aircraft data acquired at the 1979 Southeastern Virginia Urban Plume Study are also presented, which illustrate the application of the instrument to a troposphere pollution plume.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; Oct. 198
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  • 44
    Publikationsdatum: 2011-08-18
    Beschreibung: A multichannel scanning radiometer developed for remote observation of cloud physical properties is described. Consisting of six channels in the near infrared and one channel in the thermal infrared, the instrument can observe cloud physical parameters such as optical thickness, thermodynamic phase, cloud top altitude, and cloud top temperature. Measurement accuracy is quantified through flight tests on the NASA CV-990 and the NASA WB-57F, and is found to be limited by the harsh environment of the aircraft at flight altitude. The electronics, data system, and calibration of the instrument are also discussed.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; Oct. 198
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  • 45
    Publikationsdatum: 2011-08-18
    Beschreibung: A comparison of measured and predicted signal-to-noise ratio is made in an optical heterodyne spectrometer utilizing a tunable diode laser which exhibited excess noise. It is shown that good agreement between predicted and measured signal-to-noise ratios results if excess noise effects due to tunable diode lasers are included in the predictions. The methods used to quantify excess noise and to incorporate their effects into predictions of signal-to-noise ratio are discussed.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Physics Letters; 39; Nov. 1
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  • 46
    Publikationsdatum: 2011-08-18
    Beschreibung: An analysis is made of the influence of landing gear deflection characteristics on aircraft performance on the ground up to rotation. A quasi-steady dynamic equilibrium state is assumed, including other simplifying assumptions such as calm air conditions and normal aircraft lift and drag. Ground incidence is defined as the angle made by the mean aerodynamic chord of the wing with respect to the ground plane, and equations are given for force and balance which determine the quasi-equilibrium conditions for the aircraft during ground roll. Results indicate that the landing gear deflections lead to a substantial increase in the angle of attack, and the variation in the ground incidence due to landing gear flexibility could be as much as + or - 50%, and the reduction in tail load requirements almost 25%.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Journal of Aircraft; 18; Nov. 198
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  • 47
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    Publikationsdatum: 2011-08-18
    Beschreibung: It is pointed out that no instrument is sensitive to only one oceanographic variable; rather, each responds to a combination of atmospheric and oceanic phenomena. This complicates data interpretation and usually requires that a number of observations, each sensitive to somewhat different phenomena, be combined to provide unambiguous information. The distinction between active and passive instruments is described. A block diagram illustrating the steps necessary to convert data from satellite instruments into oceanographic information is included, as is a diagram illustrating the operation of a radio-frequency radiometer. Attention is also given to the satellites that carry the various oceanographic instruments.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Oceanus; 24; Fall 198
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  • 48
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    Publikationsdatum: 2011-08-18
    Beschreibung: The use of a laser diode as a light source for a schlieren system designed to study phase objects such as a wind-tunnel flow is explored. A laser diode schlieren photograph and a white light schlieren photograph (zirconium arc source) are presented for comparison. The laser diode has increased sensitivity, compared with light schlieren, without appreciable image degradiation, and is an acceptable source for schlieren flow visualization.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Optical Engineering; 20; Sept
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  • 49
    Publikationsdatum: 2011-08-18
    Beschreibung: The design complexity and size of convectively-cooled engine and airframe structures for hypersonic transports necessitate the use of large general purpose computer programs for both thermal and structural analyses. Generally thermal analyses are based on the lumped-parameter finite difference technique, and structural analyses are based on the finite element technique. Differences in these techniques make it difficult to achieve an efficient interface. It appears, therefore, desirable to conduct an integrated analysis based on a common technique. A summary is provided of efforts by NASA concerned with the development of an integrated thermal structural analysis capability using the finite element method. Particular attention is given to the development of conduction/forced-convection finite element methodology and applications which illustrate the capabilities of the developed concepts.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 50
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    Publikationsdatum: 2011-08-18
    Beschreibung: Attention is given to a microplasma discharge to initiate a hollow cathode discharge for such applications as plasma flow experiments, the electric propulsion of space vehicles, and as a replacement for filament cathodes in neutral beam injector ion sources. The technique results in a cathode that is easy to start, simple in design, and which does not require external RF exciters, inserts or heating elements. Future applications may include ion beam milling and ion implantation.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; Aug. 198
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  • 51
    Publikationsdatum: 2011-08-18
    Beschreibung: An improved formula for continuous-wave ultrasonic phase velocity measurements using contact transducers is derived from the transmission line theory. The effect of transducer-sample coupling bonds is considered for measurements of solid samples even though it is often neglected because of the difficulty of accurately determining the bond thickness. Computer models show that the present formula is more accurate than previous expressions. Laboratory measurements using contacting transducers with the present formula are compared to measurements using noncontacting (hence effectively correction-free) capacitive transducers. The results of the experiments verify the validity and accuracy of the new formula.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Journal of Applied Physics; 52; May 1981
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  • 52
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    Publikationsdatum: 2011-08-18
    Beschreibung: A correction is presented for a previously published inconsistency in predicted airframe noise values, which were based on approach velocities lower than those required for FAA certification. New figures are given for the following aircraft: DC-9-30, 727-200, A300-B2, L-1011, DC-10-10, and 747-200B. The new levels average 2.3 dB higher than those calculated for typical approach speeds.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Journal of Aircraft; 18; Sept
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  • 53
    Publikationsdatum: 2011-08-18
    Beschreibung: The feasibility of the Lixiscope (Low Intensity X-ray Imaging Scope) is demonstrated for real-time observation of transmission Laue patterns. Making use of the high-gain capability of microchannel plate (MCP) visible-light image intensifier tubes, X-ray images are converted to visible-light images by a scintillator. Pb discs are taped to the center of the Lixiscope input face, and crystal samples are held on a goniometer stage with modeling clay. With a compact size to facilitate off axis viewing, and real-time viewing to allow instantaneous response, the Lixiscope may prove useful in dynamic studies of the effects of plastic flows, stresses, high pressures, and low temperatures.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; July 198
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  • 54
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    Publikationsdatum: 2011-08-18
    Beschreibung: An unbaked calibration system is described that permits absolute calibration with a piston manometer in the range 0.0002 to 6 Pa, with a probable error of 5 microPa + 0.8%, or in the range 0.00008 to 0.02 Pa, with a probable error of 2 microPa + 1%. Procedures and techniques that permit this performance are detailed. For hot-cathode ion gauges, the magnitudes of systematic corrections for envelope temperature and grid current are also indicated.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Journal of Vacuum Science and Technology; 19; July-Aug
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  • 55
    Publikationsdatum: 2011-08-18
    Beschreibung: Laboratory and flight radiometric performance testing of an experimental multispectral scanner system is described. High sensitivity performance is confirmed by test results using noise equivalent spectral radiance as the primary figure of merit. A performance comparison between the test-bed aircraft multispectral scanner (TBAMS) and the Bendix modular multispectral scanner (M2S) is presented. Methods for achieving high sensitivity operation are discussed as well as some of the practical implications of such operation for flight remote sensing experiments.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Optical Engineering; 20; Sept
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  • 56
    Publikationsdatum: 2011-08-18
    Beschreibung: The development of a comprehensive analytical model of rotorcraft aerodynamics and dynamics is described. Particular emphasis is given to describing the reasons behind the choices and decisions involved in constructing the model. The analysis is designed to calculate rotor performance, loads and noise; helicopter vibration and gust response; flight dynamics and handling qualities; and system aeroelastic stability. It is intended for use in the design, testing and evaluation of a wide class of rotors and rotorcraft, and to be the basis for further development of rotary wing theories. The general characteristics of the geometric, structural, inertial, and aerodynamic models used for the rotorcraft components are described, including the assumptions introduced by the chosen models and the resulting capabilities and limitations. Finally, some examples from recent applications of the analysis are given.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Vertica; 5; 2, 19; 1981
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  • 57
    Publikationsdatum: 2011-08-18
    Beschreibung: High frequency plane gratings (3500 and 3600 gr/mm) have been holographically ruled and blazed for the VUV spectral region. All gratings were coated with 70 nm Al + 25 nm MgF2. Absolute unpolarized and S- and P-plane polarization efficiencies have been measured for the first and second orders in the 120- to 450-nm spectral region at 18.5 and 30 deg angles of deviation. For deep grooves, anomalous features are more pronounced for the P-plane polarization efficiency than for the S-plane polarization efficiency. Holographic gratings can be tailored to produce high polarization or low polarization in the VUV. For comparison, efficiencies and polarization of the best conventional high frequency gratings were also determined. Measurements show that scattered light is significantly lower for holographic gratings in the VUV when compared with the conventional gratings.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; May 15
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  • 58
    Publikationsdatum: 2011-08-18
    Beschreibung: An analysis of different preamplification systems for use with room temperature mercuric iodide X-ray detectors has been performed. Resistor-, drain-, and light-feedback preamplifiers have been studied. Energy resolution values of 295 eV (FWHM) for an Fe-55 source (5.9 keV) and 225 eV (FWHM) for a pulser have been obtained with both the detector and the input FET at room temperature using a pulsed-light feedback preamplifier. Improvement in energy resolution by cooling the input FET using a small Peltier element has been discussed.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
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  • 59
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    Publikationsdatum: 2011-08-18
    Beschreibung: The utility of the cryogenic high Reynolds number test facility as a production tunnel is evaluated. Aerodynamic performance evaluation, numerical wing design verification, and high Reynolds number theoretical extensions are considered. A priority ranking of NTF uses from an airframe development viewpoint is presented.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center High Reynolds Number Res. - 1980; p 149-152
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  • 60
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    Publikationsdatum: 2011-08-18
    Beschreibung: The significant technology items of the Concorde and the conceptual MCD baseline advanced supersonic transport are compared. The four major improvements are in the areas of range performance, structures (materials), aerodynamics, and in community noise. Presentation charts show aerodynamic efficiency; the reoptimized wing; low scale lift/drag ratio; control systems; structural modeling and analysis; weight and cost comparisons for superplasticity diffusion bonded titanium sandwich structures and for aluminum brazed titanium honeycomb structures; operating cost reduction; suppressor nozzles; noise reduction and range; the bicone inlet; a market summary; environmental issues; high priority items; the titanium wing and fuselage test components; and technology validation.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Supersonic Cruise Res., 1979, Pt. 2; p 873-888
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  • 61
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    Publikationsdatum: 2011-08-18
    Beschreibung: Graphite/epoxy panels with buffer strips were tested in tension to measure their residual strength with crack-like damage. Panels were made with 45/0/-45/90(2S) and 45/0/450(2S) layups. The buffer strips were parallel to the loading directions. They were made by replacing narrow strips of the 0 deg graphite plies with strips of either 0 deg S-Glass/epoxy or Kevlar-49/epoxy on either a one for one or a two for one basis. In a third case, O deg graphite/epoxy was used as the buffer material and thin, perforated Mylar strips were placed between the 0 deg piles and the cross-plies to weaken the interfaces and thus to isolate the 0 deg plies. Some panels were made with buffer strips of different widths and spacings. The buffer strips arrested the cracks and increased the residual strengths significantly over those plain laminates without buffer strips. A shear-lag type stress analysis correctly predicted the effects of layups, buffer material, buffer strip width and spacing, and the number of plies of buffer material.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Supersonic Cruise Res., 1979, Pt. 2; p 657-673
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  • 62
    Publikationsdatum: 2011-08-18
    Beschreibung: NASA Langley Research Center SCAR in-house structural studies are reviewed. In methods development, advances include a new system of integrated computer programs called ISSYS, progress in determining aerodynamic loads and aerodynamically induced structural loads (including those due to gusts), flutter optimization for composite and metal airframe configurations using refined and simplified mathematical models, and synthesis of active controls. Results given address several aspects of various SCR configurations. These results include flutter penalties on composite wing, flutter suppression using active controls, roll control effectiveness, wing tip ground clearance, tail size effect on flutter, engine weight and mass distribution influence on flutter, and strength and flutter optimization of new configurations. The ISSYS system of integrated programs performed well in all the applications illustrated by the results, the diversity of which attests to ISSYS' versatility.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Supersonic Cruise Res., 1979, Pt. 2; p 617-656
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  • 63
    Publikationsdatum: 2011-08-18
    Beschreibung: The superplastically formed diffusion-bonded (SPF/DB) program has developed successfully and far enough to recommend that a major structural program to validate the weight and cost of SPF/DB sandwich titanium structure should be initiated. The NASA Langley study of wing and fuselage SPF/DB sandwich panels shows that this process is potentially structurally efficient. The Douglas SPF/DB expanded sandwich process that utilizes a welded core sheet that expands to face sheets proves to be very efficient. The theoretical weight optimization design charts for the wing and fuselage concepts were validated by small-scale tests. Mnay design applications were fabricated. Projecting the results of an SPF/DB sandwich airframe structure to a MDC AST design shows significant weight and cost savings. A 6 percent lower direct operating cost was calculated. A growth AST utilizing composites, metal matrices, and SPF/DB sandwich shows future promise for a post-1990 technology readiness. Titanium SPF/DB sandwich, compared to presently available aluminum structure, is superior for application to a Mach 2.2 supersonic transport.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Supersonic Cruise Res., 1979, Pt. 2; p 589-616
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  • 64
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    Publikationsdatum: 2011-08-18
    Beschreibung: The efficiency of coherent anti-Stokes Raman scattering (CARS) is calculated as a function of the input beam sizes of the Stokes and pump laser beams. A Green's function formalism is used to show that maximum efficiency occurs when the confocal parameters of the two input beams are unequal and when the phase mismatch between the anti-Stokes field and the nonlinear polarization is nonzero.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Journal of Chemical Physics; 75; Sept. 15
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  • 65
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    Publikationsdatum: 2011-08-18
    Beschreibung: Photographs show the efficiency and resolution characteristics of single X-ray photons converted to optical photons in a variety of commercial X-ray phosphor screens. The recording system uses a cooled, two-stage image intensifier system with fiber optics coupling to the phosphor screen. High efficiencies in the energy range 20-100 keV with position resolution of the order 200 microns are readily achievable, although the sensitive area is presently limited. Potential applications include X-ray astronomy, high-speed X-ray diffractometry, and extremely low dose radiography.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Review of Scientific Instruments; 52; Aug. 198
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  • 66
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    Publikationsdatum: 2011-08-18
    Beschreibung: The use of photoelastic polarimeters in astronomy is briefly reviewed, and a visible and near-UV photoelastic modulation polarimeter is described which has been in continuous service on the 61-cm telescope of Pine Mountain Observatory for 6 years. The polarimeter is used primarily for linear polarization measurements, but is easily adaptable to circular polarimetry. The instrument has produced data at a sensitivity level of 0.01%, with long-term absolute reproducibility.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Astronomical Society of the Pacific; vol. 93
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  • 67
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    Publikationsdatum: 2011-08-18
    Beschreibung: Rapid-double-exposure, diffuse-illumination holography is evaluated analytically and experimentally as a flow visualization method for time-varying shock waves. Conditions are determined that minimize the distance (localization error) between the surface or curve of interference-fringe localization and the shock surface. Treated specifically are the cases of shock waves in a transonic compressor rotor for which there is laser anemometer data for comparison and shock waves in a flutter cascade.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Applied Optics; 20; Sept. 15
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  • 68
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    Publikationsdatum: 2011-08-18
    Beschreibung: A three-band Linear Array Pushbroom Radiometer (LAPR) was built and flown on an experimental basis by NASA, at the Goddard Space Flight Center. The functional characteristics of the instrument and the methods used to preprocess the data, including radiometric correction, are described. The radiometric sensitivity of the instrument was tested and compared to that of the Thematic Mapper and the Multispectral Scanner. The radiometric correction procedure was evaluated quantitatively, using laboratory testing, and qualitatively, by visual examination of the LAPR test flight imagery. Although effective radiometric correction could not yet be demonstrated by laboratory testing, radiometric distortion did not preclude the visual interpretation or classification of the test imagery.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Photogrammetric Engineering and Remote Sensing; 47; May 1981
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  • 69
    Publikationsdatum: 2011-08-18
    Beschreibung: Experiments have verified the existence of considerable delayed darkening in FWT-60 dosimetry films that may, depending on relative humidity, last for several hours. The amount of delayed darkening depends very strongly on the relative humidity at which the films are equilibrated before irradiation. It is pointed out that the delayed darkening effect must be taken into account before any meaningful dosimetric measurements may be made using these nylon-based thin dosimetry films. The particular radiation-sensitive compound used in the FWT-60 films is the hexahydrosyethyl pararosanaline cyanide with the Dupont nylon resin, Elvamide 8061, which forms the host matrix of a solid-state solution.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
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  • 70
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    In:  Other Sources
    Publikationsdatum: 2011-08-18
    Beschreibung: The NASA early experimental program for parawing and lifting body spacecraft recovery concepts is discussed. Simple hand drawings, in-house construction, and crude drop tests were used in lieu of a thorough stress analysis. The parawing (parasev) was controlled by manually shifting the center of gravity with respect to the center of pressure; the craft would take off while being towed at 40 KIAS. The M-2 lifting body was originally constructed with a 3/32 in. mahogany skin by a glider manufacturer and employed general aviation aircraft nose and main wheel assemblies. A minimum altitude of 200 ft was found acceptable for release of the parasev, allowing the pilot time to adjust for transients incurred at the tow release. A small landing assist rocket was furnished for the M-2/F-2 and X-24A lifting bodies to enhance stability, and landings at a maximum lift/drag ratio of 2.8 were successfully completed. The data gained were eventually applied in the development of the Shuttle.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 71
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    In:  Other Sources
    Publikationsdatum: 2011-08-18
    Beschreibung: The X-14 V/STOL research aircraft made its first free-hover flight as a proof-of-concept test-bed on Feb. 19, 1957. With the exception of two subsequent modification periods (to X-14A and X-14B) this V/STOL 'workhorse' has been on continuous flight-test status as a research aircraft and flying classroom. The paper presents some of the highlights of its memorable 24-year flight-test career with special emphasis on projects which have contributed to V/STOL technology and on the test pilots who made it happen.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
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  • 72
    Publikationsdatum: 2017-10-02
    Beschreibung: The application and analysis of dynamic stability parameters were examined. The effects of wing leading edge modifications on the stalling and spinning characteristics of a single engine general aviation research airplane are evaluated. It is illustrated how dynamic stability parameters measured in wind tunnel tests are used to predict the spin resistance of this class of aircraft, and that autorotation criteria are derived from the relationships which exist between static and dynamic aerodynamic characteristics.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: AGARD Dyn. Stability Parameters; 12 p
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  • 73
    Publikationsdatum: 2017-10-02
    Beschreibung: Two applications of mathematical modeling to aerodynamic problems are cussed. The first application is an investigation of the capacity of a nonlinear aerodynamic mathematical model to describe the aerodynamic reactions on an airfoil with a deflecting flap in transonic flow. Flow field computational methods are used to evaluate the nonlinear, unsteady aerodynamic data in terms of characteristic motions called for by the model. Histories of unconstrained motions of the flap are generated from the flap equations of motion, with the aerodynamic reactions specified by the mathematical model. In the second application wing rock is investigated. The most recent model accommodates experimental results wing rock by admitting the existence of aerodynamic hysteresis in the variation of the steady state rolling moment coefficient with roll angle is described.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: AGARD Dyn. Stability Parameters; 15 p
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  • 74
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    In:  CASI
    Publikationsdatum: 2017-10-02
    Beschreibung: The mathematical modeling of the aerodynamic response of an aircraft to arbitrary maneuvers is reviewed. Bryan's original formulation, linear aerodynamic indicial functions, and superposition are considered. These concepts are extended into the nonlinear regime. The nonlinear generalization yields a form for the aerodynamic response that can be built up from the responses to a limited number of well defined characteristic motions, reproducible in principle either in wind tunnel experiments or flow field computations. A further generalization leads to a form accommodating the discontinuous and double valued behavior characteristics of hysteresis in the steady state aerodynamic response.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: AGARD Dyn. Stability Parameters; 31 p
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  • 75
    Publikationsdatum: 2017-10-02
    Beschreibung: Some of the problems associated with using military specification MIL-W-5088H as a guideline for wire gage selection are discussed. Examples of proper use of this specification as a criterion for interfacting wire bundles and connectors are provided. The quantitative results of 22 projects that have used the technique known as sneak analysis are reviewed and examples are given.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: AGARD Subsystem Testing and Flight Test Instr.; 16 p
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  • 76
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Examples of experiment theory correlation are presented to give an indication of the capabilities and limitations of wing design and analysis for transonic applications by potential flow theory. The examples include correlations of experimental pressure distributions with theoretical results from isolated wing codes and wing-body codes. Both conservative and non conservative differencing as well as body and boundary layer corrections are considered. A full potential isolated wing code correlates well with data from an isolated wing test but may give poor prediction of the aerodynamic characteristics of some wing-body configurations. Potential flow wing body codes were found to improve the correlation for the wing-body configurations considered.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Advan. Aerodyn. and Active Controls; p 157-169
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  • 77
    Publikationsdatum: 2016-06-07
    Beschreibung: Results from flight tests of the ARW-1 research wing are presented. Preliminary loads data and experiences with the active control system for flutter suppression are included along with comparative results of test and prediction for the flutter boundary of the supercritical research wing and on performance of the flutter suppression system. The status of the ARW-2 research wing is given.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Advan. Aerodyn. and Active Controls; p 21-36
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  • 78
    facet.materialart.
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The results of contracted studies identifying the potential benefits of advanced technology are presented. Current in house studies and research efforts are discussed. An overview of the proposed technology elements in STAT research is presented.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Advan. Aerodyn. and Active Controls; p 85-104
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  • 79
    Publikationsdatum: 2016-06-07
    Beschreibung: The basic parameters relevant to the design of network timing systems describe the random and systematic time departures of the system elements, i.e., master (or reference) clocks, transmission links, and other clocks controlled over the links. The quantitative relations between these parameters were established and illustrated by means of numerical examples based on available measured data. The examples were limited to a simple PLL control system but the analysis can eventually be applied to more sophisticated systems at the cost of increased computational effort.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 515-549
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  • 80
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: As a power utility, Hydro-Quebec used the PTTI techniques. The time dissemination system in the Hydro-Quebec Network (11th PTTI) is now installed in several points. A portable clock was built using a rubidium standard and associated circuitry which are necessary for the measurements. The apparatus and the experimental results obtained are described. The use of GOES synchronized clocks for making precise voltage angle measurement on the Hydro-Quebec Network is discussed. Some modifications were made on a commercial unit. Applications and results are presented.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 377-385
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  • 81
    Publikationsdatum: 2016-06-07
    Beschreibung: A two-way time synchronization experiment performed in the spring of 1979 and 1980 via the Italian SIRIO-1 experimental telecommunications satellite is described. The experiment was designed and implemented to precisely monitor the satellite motion and to evaluate the possibility of performing a high precision, two-way time synchronization using a single communication channel, time-shared between the participating sites. Results show that the precision of the time synchronization is between 1 and 5 ns, while the evaluation and correction of the satellite motion effect was performed with an accuracy of a few nanoseconds or better over a time interval from 1 up to 20 seconds.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 329-350
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  • 82
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Three KC-135 winglet configurations were flight tested for cant/incidence angles of 15 deg/-4 deg, 15 deg/-2 deg, and 0 deg/-4 deg, as well as the basic wing. The flight results for the 15 deg/-4 deg and basic wing configurations confirm the wind tunnel predicted 7% incremental decrease in total drag at cruise conditions. The 15 deg/-4 configuration flight measured wing and winglet pressure distributions, loads, stability and control, flutter, and buffet also correlate well with predicted values. The only unexpected flight results as compared with analytical predictions is a flutter speed decrease for the 0 deg/-4 deg configuration. The 15 deg/-2 deg configuration results show essentially the same incremental drag reduction as the 15 deg/-4 deg configuration; however, the flight loads are approximately 30% higher for the 15 deg/-2 deg configuration. The drag data for the 0 deg/-4 deg configuration show only a flight drag reduction.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA. Langley Research Center Advan. Aerodyn. and Active Controls; p 145-156
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  • 83
    Publikationsdatum: 2016-06-07
    Beschreibung: A modified wing with the long core separate flow nacelle and several E(3) nacelles was utilized. The effects of nacelle and pylon cant angles and nacelle longitudinal and vertical location were investigated over a Mach number range from 0.70 to 0.83. The results at the cruise condition 0.82 Mach number and 0.55 lift coefficient are presented.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Advan. Aerodyn. and Active Controls; p 105-122
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  • 84
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The optimal control model for pilot vehicle systems was used to develop a methodology for predicting pilot ratings for commercial transports. The method was tested by applying it to a family of transport configurations for which subjective pilot ratings were obtained. Specific attention is given to the development of the simulator program and procedures so as to yield objective and subjective performance data useful for a critical evaluation of the analytical method.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: Advan. Aerodyn. and Active Controls; p 37-42
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  • 85
    Publikationsdatum: 2016-06-07
    Beschreibung: Continuous phase recording of the 16kHz transmission from GBR (UK) are being made and published midday phase data of GBR are received regularly from laboratories in the US, FGR, and UK. The local time scale (UTC, India), at the National Physical Laboratory in New Delhi, and those at the foreign laboratories are intercompared using the VLF phase data. A major factor which limits the accuracy of long term comparison is the seasonal variation in the VLF over delay over long paths. By taking into account the seasonal delay variations in a semiempirical way, the accuracy of time and frequency comparisons can be improved. Over a one year period, accuracy of a few parts in 10 to the 14th power in frequency and 1 to 2 micron sec in time were obtained. The relative frequency offset difference between UTC, (India) and UTC (PTB, Germany) of (7.0 + or - 0.1) x 10 to the -13 power agrees well with that obtained in a satellite experiment.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 851-862
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  • 86
    Publikationsdatum: 2016-06-07
    Beschreibung: Minimum variance estimation requires that the statistics of random observation errors be modeled properly. If measurements are derived through the use of atomic frequency standards, then one source of error affecting the observable is random fluctuation in frequency. This is the case, for example, with range and integrated Doppler measurements from satellites of the Global Positioning and baseline determination for geodynamic applications. An analytic method is presented which approximates the statistics of this random process. The procedure starts with a model of the Allan variance for a particular oscillator and develops the statistics of range and integrated Doppler measurements. A series of five first order Markov processes is used to approximate the power spectral density obtained from the Allan variance.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 551-580
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  • 87
    Publikationsdatum: 2016-06-07
    Beschreibung: At NASA Goddard Space Flight Center and through associated contractors, a broad spectrum of work is being carried out to develop improved hydrogen maser frequency standards for field use, improved experimental hydrogen maser frequency standards, and improved frequency and time distribution and measurement systems for hydrogen maser use. Recent progress in the following areas is reported: results on the Nr masers built by the Applied Physics Laboratory of Johns Hopkins University, the development of a low cost hydrogen maser at Goddard Space Flight Center, and work on a low noise phase comparison system and digitally phase locked crystal oscillator called the distribution and measurement system.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 463-493
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  • 88
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Initial test results indicated that the Global Positioning System/Time Transfer Unit (GPS/TTU) performed well within the + or - 100 nanosecond range required by the original system specification. Subsequent testing involved the verification of GPS time at the master control site via portable clocks and the acquisition and tracking of as many passes of the space vehicles currently in operation as possible. A description and discussion of the testing, system modifications, test results obtained, and an evaluation of both GPS and the GPS/TTU are presented.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 387-415
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  • 89
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: The LASSO (Later Synchronisation from Stationary Orbit) experiment, designed to demonstrate the feasibility of achieving time synchronization between remote atomic clocks with an accuracy of one nanosecond or better by using laser techniques for the first time is described. The experiment uses groundbased laser stations and the SIRIO-2 geostationary satellite to be launched towards the end of 1981. The qualification of the LASSO on-board equipment is discussed with a brief description of the electrical and optical test equipment used. The progress of the operational organization is included.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 307-327
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  • 90
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Innovation and reliability in hyperfine frequency standards and clock systems are discussed. Hyperfine standards are defined as those precision frequency sources and clocks which use a hyperfine atomic transition for frequency control and which have realized significant commercial production and acceptance (cesium, hydrogen, and rubidium atoms). References to other systems such as thallium and ammonia are excluded since these atomic standards have not been commercially exploited in this country.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 275-280
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  • 91
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: Methods of resolving the iron lines, the most common X-ray emission lines in both galactic and extragalactic X-ray sources, are reviewed. A self-focussing crystal spectrometer is shown to be the most suitable instrument, and the optimum crystal geometry is spherical (Schnopper and Taylor 1980). The principles of operation of such a spherical crystal imaging spectrometer are examined and its sensitivity is shown to be two orders of magnitude better than a focal plane crystal spectrometer on AXAF. A Spacelab version of this payload would be very cost-effective.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center X-ray Astronomy in the 1980's; p 497-522
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  • 92
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: A wide-field soft X-ray camera (WFSXC) sensitive in the 50 to 250 eV band is described. The camera features Wolter-Schwarzschild optics with an 8 degree field of view and 300 cu cu collecting area. The focal plane instrument is a microchannel plate detector. Broad-band energy discrimination is provided by thin-film filters mounted immediately in front of the focal plane. The WFSXC is capable of detecting sources with intensities greater than 5 percent of HZ 43 during typical sounding rocket exposures, and it would approach the same sensitivity range as EUVE during a typical exposure from the Shuttle.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center X-ray Astronomy in the 1980's; p 319-323
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  • 93
    Publikationsdatum: 2016-06-07
    Beschreibung: A time and frequency intercomparison experiment conducted using Earth stations in New Delhi, India and Raisting, FRG is described. The NPL clock was placed at New Delhi Earth Station and the Raisting Clock was calibrated with PTB/Primary standard via LORAN-C and travelling clocks. The random uncertainity of time comparisons, represented by two sample Allan Variance sigma (30 seconds), was less than 10 nanoseconds. The relative frequency difference between the NPL and Raisting Clocks, SNPL, RAIS, as measured over the 44 days period was found to be -15.7 x 10 to the -13th power. The relative frequency difference between PTB Primary Standard and Raisting Clock, SPTB, RAIS, during this period, was measured to be -22.8 x 10 to the -13th power. The relative frequency difference between NPL clock and PTB Primary Standard, SNPL, PTB, thus, is +7.1 x 10 to the -13th power. The clock rate (UTC, India) of +7.1 + or - 0.5 x 10 to the -13th power, agrees well with that obtained via VLF phase measurements over one year period and with USNO travelling clock time comparisons made in September, 1980.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 863-874
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  • 94
    Publikationsdatum: 2016-06-07
    Beschreibung: A satellite time receiver was tested in various environmental conditions during the past year. The commercial receiver designed to work with the National Oceanic and Atmospheric Administration's (NOAA) Geostationary Operational Environmental Satellites (GOES). The test program included operation at low elevation during flight in a military cargo aircraft and long term comparison with laboratory standards. The GOES satellite time receiver offers an opportunity to provide easy wide area coverage synchronization at low cost.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center Proc. of the 12th Ann. Precise Time and Time Interval Appl. and Planning Meeting; p 351-376
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  • 95
    Publikationsdatum: 2016-06-07
    Beschreibung: A spherical array of twenty LiF 200 crystals was built to test the performances of a freestanding, self-focussing spherical crystal cosmic X-ray spectrometer. Measurements presently available show that the size of the image for a point source at infinite distance would be 3 mm (FWHM) along the focalisation axis and 2.1 mm (FWHM) along the dispersion axis. The mosaic spread on individual crystals is less than 0.1 degree. A slightly systematic deviation from the ideal bending (0.1 degree) is observed at the edges of most crystals and this appears to be the major limitation to spectrometer performance.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center X-ray Astronomy in the 1980'; p 523-526
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  • 96
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    In:  CASI
    Publikationsdatum: 2016-06-07
    Beschreibung: A design for a diffuse X-ray spectrometer utilizing Bragg reflection is described. The geometry has a very high throughput for a given physical size and allows simultaneous observation at all wavelengths within its range. Spectral resolving power is about 35 to 50. A similar unit equipped with thallium acid pthallate crystals will cover the 11 - 24 A-range with about half this throughput and twice the resolving power.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center X-ray Astronomy in the 1980's; p 379-401
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  • 97
    Publikationsdatum: 2016-06-07
    Beschreibung: Results of intial performance tests on X-ray sensing properties of charge-coupled devices (CCDs) are presented. CCDs have demonstrated excellent spatial resolution and good spectral resolution, superior to that of non-imaging proportional counters.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA. Goddard Space Flight Center X-ray Astronomy in 1980's; p 289-299
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  • 98
    Publikationsdatum: 2019-06-28
    Beschreibung: A 4.5 percent DC-10 derivative flexible model with active controls is fabricated, developed, and tested to investigate the ability to suppress flutter and reduce gust loads with active controlled surfaces. The model is analyzed and tested in both semispan and complete model configuration. Analytical methods are refined and control laws are developed and successfully tested on both versions of the model. A 15 to 25 percent increase in flutter speed due to the active system is demonstrated. The capability of an active control system to significantly reduce wing bending moments due to turbulence is demonstrated. Good correlation is obtained between test and analytical prediction.
    Schlagwort(e): AIRCRAFT DESIGN, TESTING AND PERFORMANCE
    Materialart: NASA-CR-3472 , NAS 1.26:3472
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  • 99
    Publikationsdatum: 2019-06-28
    Beschreibung: The Pinhole Occulter Facility (P/OF) is a Space Shuttle based experiment for the production of solar coronographics and hard X-ray images. The system is basically pinhole camera utilizing a deployable 50-m flexible boom for separating the pinholes and coronograph shields from the recording devices located in the Shuttle bay. At the distal end of the boom from the Shuttle is a 25 kg mask containing pinholes and coronograph shields. At the proximal end the detectors are located and mounted, along with the deployable boom, to the ASPS gimbal pointing system (AGS). The mask must be pointed at the Sun with a high degree of pointing stability and accuracy to align the axes of the detectors with the pinholes and shields. Failure to do so will result in a blurring of the images on the detectors and a loss of resolution. Being a Shuttle based experiment, the system will be subjected to the disturbances of the Shuttle. The worst of these is thruster firing for orbit correction; the Shuttle uses a bang-bang thruster control system to maintain orbit to within preset limits. Other disturbances include man motion, motion induced by other systems, and gravity gradient torques.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
    Materialart: NASA-CR-171152 , NAS 1.26:171152 , BER-274-100
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  • 100
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    In:  Other Sources
    Publikationsdatum: 2019-06-28
    Beschreibung: An analysis of pixel labeling by probabilistic relaxation techniques is presented to demonstrate that these labeling procedures degenerate to weighted averages in the vicinity of fixed points. A consequence of this is that undesired label conversions can occur, leading to a deterioration of labeling accuracy at a stage after an improvement has already been achieved. Means for overcoming the accuracy deterioration are suggested and used as the basis for a possible design strategy for using probabilistic relaxation procedures. The results obtained are illustrated using simple data sets in which labeling on individual pixels can be examined and also using Landsat imagery to show application to data typical of that encountered in remote sensing applications.
    Schlagwort(e): INSTRUMENTATION AND PHOTOGRAPHY
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