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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 397 records · Page 22

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NASA NTRS1974

Wind Tunnel Generation of Sinusoidal Lateral and Longitudinal Gusts by Circulation of Twin Parallel Airfoils

A gust generator capable of producing sinusoidal lateral and longitudinal gusts was developed for the purpose of studying the gust response of a model rotor-propeller in a wind tunnel. The gust generator utilized harmonic circulation control of twin parallel airfoils to achieve the harmonic lift variation required for gust generation. The gust generator design, construction, and testing is described. Typical test results are presented in the form of lateral and longitudinal gust perturbation velocities as a function of generator reduced frequency.

Ham, N. D.↗

NASA NTRS1974

The comparative evaluation of ERTS-1 imagery for resource inventory in land use planning

The author has identified the following significant results. Multidiscipline team interpretation and mapping of resources for Crook County is complete on 1:250,000 scale enlargements of ERTS imagery and 1:120,000 hi-flight photography. Maps of geology, soils, vegetation-land use and land resources units were interpreted to show limitations, suitabilities, and geologic hazards for land use planning. Mapping of lineaments and structures from ERTS imagery has shown a number of features not previously mapped in Oregon. A multistage timber inventory of Ochoco National Forest was made, using ERTS images as the first stage. Inventory of forest clear-cutting practices was successfully demonstrated with color composites. Soil tonal differences in fallow fields correspond with major soil boundaries in loess-mantled terrain. A digital classification system used for discriminating natural vegetation and geologic material classes was successful in separating most major classes around Newberry Caldera, Mt. Washington, and Big Summit Prairie.

Schrumpf, B. J.↗

NASA NTRS1974

Vacuum UV photolysis of N2O

Emission from N2 B (3 Pi g) and O(1 S) produced during vacuum UV irradiation of N2O was studied as a function of the wavelength of the incident radiation. Two different processes were responsible for producing N2(B 3 Pi g) close to its production threshold. One process formed B 3 Pi g molecules directly and one indirectly via an unidentified precursor having a lifetime about 27 microsec. The quantum yield of O(1 S) atoms produced by photodissociation of N2O was determined as a function of incident photon energy. This yield is near 100% at 129 nm.

Mcewan, M. J.↗

NASA NTRS1975

Mission analysis for satellite measurements of stratospheric constituents by solar occultation

Orbital characteristics and launch vehicle requirements for a solar occultation experiment measuring atmospheric constituents, such as aerosols or ozone, during the Nimbus-G and Applications Explorer Missions are analyzed. The experiment to be flown is basically a sun photometer which measures the spectral attenuation of solar radiation by the earth's atmosphere during spacecraft sunrise and sunset, yielding two aerosol and/or ozone stratospheric profiles per orbit. The tangent latitudes and longitudes as well as frequency of these measurements are analyzed for various spacecraft orbits to define maximum geographical coverage capability. Results indicate that a 50 deg inclined orbit for Applications Explorer provides latitude coverage from approximately 70 deg north to 70 deg south every 2-1/2 weeks. A high-moon, sun-synchronous orbit with an inclination of 99 deg for Nimbus-G will provide for coverage of occultation measurements at high latitudes near the polar regions (i.e., 64 to 80 deg north and south). The solar pointing requirements of the experiment in terms of yaw and pitch angles are also defined.

Harrison, E. F.↗

NASA NTRS1975

Constant energy partitioning in the photoionization of NO and O2

Published data on the photoelectron spectra of NO and O2 are analyzed, and the energy distributions are found to have averages proportional to the available energy. Hence, vibration takes a constant fraction of the energy. Average distributions are found as a function of the fraction of available energy.

Lawrence, G. M.↗

NASA NTRS1975

Ultraviolet spectrograph using microchannel plates

An ultraviolet spectrograph was constructed using double microchannel plates as detectors at the focal plane. The photoelectron pulses were located one at a time by measuring the charge division to the ends of a resistor strip behind the microchannel plates. The system worked to 20,000 counts/sec and gave resolution exceeding 100 elements.

Lawrence, G. M.↗

NASA NTRS1975

Geology and forestry classification from ERTS-1 digital data

Computer classifications into seven and ten classes of two areas in central Oregon of interest to geology and forestry demonstrate the extraction of information from ERTS-1 data. The area around Newberry Caldera was classified into basalt, rhyolite obsidian, pumice flats, Newberry pumice, ponderosa pine, lodgepole pine, and water classes. The area around Mt. Washington was classified into two basalts, three forest, two clearcut, burn, snow, and water classes. Both also include an unclassified category. Significant details that cannot be extracted from photographic reconstitutions of the data emerge from these classifications, such as moraine locations and paleowind directions. Spectral signatures for the various rocks are comparable to those published elsewhere.

Lawrence, R. D.↗

NASA NTRS1976

Wind velocity measurement

Homodyne laser-Doppler system determines three-component wind velocity at altitudes of several kilometers in clear-air conditions. There is no need for deployment of towers, radiosondes, or for seeding airflows.

Cliff, W. C.↗

NASA NTRS1976

Airport laser-Doppler

Laser system remotely senses and tracks aircraft-wake turbulence. Other potential applications include long-range (remote) detection of airflow, monitoring smokestack exit flow velocities, and observing winds at altitude.

Coffey, E. W.↗

NASA NTRS1975

Biomedical Results of Apollo

The biomedical program developed for Apollo is described in detail. The findings are listed of those investigations which are conducted to assess the effects of space flight on man's physiological and functional capacities, and significant medical events in Apollo are documented. Topics discussed include crew health and inflight monitoring, preflight and postflight medical testing, inflight experiments, quarantine, and life support systems.

Richard S. Johnston↗

NASA NTRS1975

Apollo light flash investigations

The visual phenomenon of light flashes resulting from high energy, heavy cosmic rays penetrating the command module structure and crewmembers' eyes is investigated. Light flash events observed during dedicated sessions on Apollo 15, 16, 17 are described along with a Monte Carlo simulation of the exposure of an astronaut to cosmic radiation during a mission. Results of the Apollo Light Flash Moving Emulsion Detector experiment developed for Apollo 16 and 17 to obtain a direct record of incident cosmic ray particles are correlated with crewmembers' reports of light flashes.

W. Zachary Osborne↗

NASA NTRS1975

A Study of Gust and Control Response of Model Rotor-Propellers in a Wind Tunnel Airstream

One-ninth-scale model hingeless and gimballed rotor-propellers were tested at an advance ratio of 0.7 in the Wright Brothers Wind Tunnel at MIT, in the presence of sinusoidal longitudinal and vertical gusts produced by a gust generator of novel design. The gimballed rotor was also subjected to sinusoidal collective and cyclic control inputs. Model test data in terms of blade inplane and out-of-plane bending, longitudinal and lateral gimbal motion, wing vertical and chordwise bending, and blade and wing torsion are presented and compared with theory.

Ham, N. D.↗

NASA NTRS1976

Toxicity of the pyrolysis products of spacecraft materials

Data is presented which provides guides to (1) approximate temperature necessary to initiate thermodegradation of the polymeric materials tested, (2) the relative toxicity of thermodegradation products from the various materials, (3) the relative importance of carbon monoxide as the primary cause of death (as contrasted to cyanide or other toxic gases), and (4) whether or not the hazards of the fumes are confined to the time of exposure, or whether post-exposure death is likely. Two different experimental methods were employed.

Lawrence, W. H.↗

NASA NTRS1975

A laser Doppler system for the remote sensing of boundary layer winds in clear air conditions

The system discussed uses a laser Doppler radar in combination with a velocity azimuth display mode of scanning to determine the three-dimensional wind field in the atmospheric boundary layer. An attractive feature of this CW monostatic system is that the ambient aerosol provides a 'sufficient' scattering target to permit operation under clear air conditions. Spatial resolution is achieved by focusing.

Lawrence, T. R.↗

NASA NTRS1976

Focused laser Doppler velocimeter

A system for remotely measuring velocities present in discrete volumes of air is described. A CO2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume.

Bilbro, J. W.↗

NASA NTRS1976

Wind measurement system

A system for remotely measuring vertical and horizontal winds present in discrete volumes of air at selected locations above the ground is described. A laser beam is optically focused in range by a telescope, and the output beam is conically scanned at an angle about a vertical axis. The backscatter, or reflected light, from the ambient particulates in a volume of air, the focal volume, is detected for shifts in wavelength, and from these, horizontal and vertical wind components are computed.

Cliff, W. C.↗

NASA NTRS1977

Design and fabrication of a basic mass analyzer and vacuum system

A two-inch hyperbolic rod quadrupole mass analyzer with a mass range of 400 to 200 amu and a sensitivity exceeding 100 packs per billion has been developed and tested. This analyzer is the basic hardware portion of a microprocessor-controlled quadrupole mass spectrometer for a Gas Analysis and Detection System (GADS). The development and testing of the hyperbolic-rod quadrupole mass spectrometer and associated hardware are described in detail.

Judson, C. M.↗

NASA NTRS1977

Biomedical Results from Skylab

Through the years, the quest for more knowledge about space and its impact on man sparked the technological advances in related scientific and engineering disciplines. Happily, at this present point in human history, sufficiently advanced technology and man's will to explore the unknown joined forces to make space flight possible. Following this breakthrough, the further understanding of the nature and extent of man's capabilities in space became an urgent issue. Inquiries about how man might behave, prosper, or be adversely affected in the unique environment accompanying space exploration have influenced the course of the space flight program. This book chronicles the work of scientists attempting to understand the responses of man and his life processes in an environment previously totally unknown to living systems.

Richard S Johnston↗