Testicular degeneration in Macaca nemestrina monkeys used in pre-space flight tests
Pre-space flight tests effects on Macaca nemestrina monkeys spermatogenesis, considering immobilization and exposure time effects
Adey, W. R.↗
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Results for “exposure time”
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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Design of a precise servo control system
Telescope servocontrol system with low pointing error and drift rate, permitting extended time exposure photography of star or deep space probe
Winston, G. C.↗
Cape Kennedy peak wind profile probabilities for levels from 10 to 150 meters
Cape Kennedy peak wind profile probabilities at 10-150 meters for various exposure times
Bowman, W. A.↗
Quasi-steady magnetoplasmadynamic arc characteristics
Multimegawatt quasi-steady MPD arc accelerator in millisecond pulses, noting applicability to experiments requiring long exposure times
Clark, K. E.↗
Erosion of metals by multiple impacts with water
Investigation determines - relation between impact velocity and minimum number of impacts producing visible erosion, relation between high frequency fatigue stresses and number of cycles to failure, water-hammer stresses relation to high frequency endurance limit, erosion rate as exposure time function, and correlates experimental data with recent theory.
Rudy, S. L.↗
Shutter design for stereoscopic camera
Shutter design consists of two axially mounted spring driven rotating blades with two lenses mounted between the blades. Features include excellent repeatability and flash synchronization. Design permits packaging in small volume and is beneficial where focal distance, magnification, and exposure time are fixed.
Source record↗
CdS solar cell development
Effects of manufacturing process variations on CdS solar cell performance and effect of temperature and time exposure during evaporation
Nastelin, H. E.↗
A holographic system that records front-surface detail of a scene moving at high velocity
A holographic technique that uses an elliptical orientation for the holographic arrangement is discussed. It is shown that the degree of image degradation is not only a function of exposure time but also of the system used. The form of the functional system dependence is given, as well as the results of several systems tested, which verify this dependence. It is further demonstrated that the important parameter is the total motion of the target. Using the experimentally determined resolution of front-surface detail from a target with a velocity of 17,546 centimeters per second, an upper limit on target velocity for resolution of front-surface detail for a given system can be predicted.
Kurtz, R. L.↗
Developable images produced by x-rays using the nickel-hypophosphite system. 2: Exposure and development parameters for sodium hypophosphite
Crystalline sodium hypophosphite was X-irradiated and then treated with an ammoniacal nickel hypophosphite solution. Treatment resulted in the precipitation of nickel metal. The yield of nickel metal varied directly with particle size, sample weight, X-ray voltage, target current, exposure time, and development time. These findings show the process to be potentially useful in X-ray type photography. The half-life for the latent image species was found to be relatively short; but this is not critical in most X-ray photography applications. Furthermore, the work can be interpreted on the basis that a hydrogen atom is involved in the mechanism and indicates that the autocatalytic development step may be self-poisoning.
May, C. E.↗
Resin/graphite fiber composites
High temperature resin matrices suitable for use in advanced graphite fiber composites for jet engine applications were evaluated. A series of planned, sequential screening experiments with resin systems in composite form were performed to reduce the number of candidates to a single A-type polyimide resin that repetitively produced void-free, high strength and modulus composites acceptable for use in the 550 F range for 1000 hours. An optimized processing procedure was established for this system. Extensive mechanical property studies characterized this single system, at room temperature, 500 F, 550 F and 600 F, for various exposure times.
Cavano, P. J.↗
Acceptability of VTOL aircraft noise determined by absolute subjective testing
A program was conducted during which test subjects evaluated the simulated sounds of a helicopter, a tilt wing aircraft, and a 15 second, 90 PNdB (indoors) turbojet aircraft used as reference. Over 20,000 evaluations were made while the test subjects were engaged in work and leisure activities. The effects of level, exposure time, distance and aircraft design on subjective acceptability were evaluated. Some of the important conclusions are: (1) To be judged equal in annoyance to the reference jet sound, the helicopter and tilt wing sounds must be 4 to 5 PNdB lower when lasting 15 seconds in duration. (2) To be judged significantly more acceptable than the reference jet sound, the helicopter sound must be 10 PNdB lower when lasting 15 seconds in duration. (3) To be judged significantly more acceptable than the reference jet sound, the tilt wing sound must be 12 PNdB lower when lasting 15 seconds in duration. (4) The relative effect of changing the duration of a sound upon its subjectively rated annoyance diminishes with increasing duration. It varies from 2 PNdB per doubling of duration for intervals of 15 to 30 seconds, to 0.75 PNdB per doubling of duration for intervals of 120 to 240 seconds.
Sternfeld, H., Jr.↗
The human, primate and rabbit ultraviolet action spectra
A 5000 watt xenon-mercury high pressure lamp was used to produce a continuous ultraviolet spectrum. Human and animal exposures were made to establish the photokeratitis threshold and abiotic action spectrum. The lower limit of the abiotic action spectrum was 220 nm while the upper limit was 310 nm. The radiant exposure threshold at 270 nm was 0.005 watts/sq cm for the rabbit, 0.004 watts/sq cm for the primate, and 0.004 watts/ sq cm for the human. The rabbit curve was bi-peaked with minimums at 220 nm, 240 nm and 270 nm. The primate curve was tri-peaked with minimums at 220 nm, 240 nm and 270 nm. The human data showed a rather shallow curve with a minimum at 270 nm. Formulas and calculations are given to predict minimum exposure times for ocular damage to man in outer space, to establish valid safety criteria, and to establish protective design criteria.
Pitts, D. G.↗
Search for carbon 14 in tektites.
An attempt was made to detect cosmic-ray produced C-14 in australites and far-east tektites. No C-14 activity was found outside of statistical fluctuations. If a terrestrial age of 10 thousand years is assumed for australites, a maximum cosmic-ray exposure time of one thousand years is obtained for these tektites on the basis of a 2-sigma statistical error.
Boeckl, R. S.↗
The energy spectrum of primary cosmic ray electrons from 2 GeV to 200 GeV.
Use of a balloon-borne counter telescope with a gas Cerenkov counter to measure the energy of primary cosmic ray electrons between 2 and 200 GeV. Electrons are identified by the characteristic electron-photon shower which they produce in a 15 radiation length deep stack of high-Z material interleaved with scintillation counters. Calibrations with monoenergetic electrons up to 14 GeV and monoenergetic protons up to 28 GeV from accelerators are used to develop criteria to statistically separate electrons from proton-induced events. The results from six balloon flights (total exposure time 63 hours) are combined to obtain the electron energy spectrum. Up to about 30 GeV, the spectrum measured in this experiment can be directly checked with calibrations and agrees well with results from other experiments. Above this energy, the flux reported in the present work is somewhat higher than the determinations reported by most other authors. An apparent flattening of the energy spectrum above 50 GeV is not regarded as significant. There is no evidence for a steepening of the spectrum at energies below 200 GeV.
Fanselow, J. L.↗
A high-speed spectrograph shutter
Device can operate in close-open-close mode. Beam splitter placed behind static-slit assembly allows use of more than one camera. Each frame in particular series may be conveniently varied in exposure time and spacing. This can be done independent of other frames in the series. In ''open'' position, shutter transmits light over wide wavelength range.
Miller, M. H.↗
Vapor-deposited platinum as a fuel-cell catalyst
Electrodes are prepared by vacuum deposition of platinum on nickel substrate with conventional vapor-deposition apparatus. Amount of platinum loaded on substrate can be veried by changing exposure time during deposition. These electrodes are significantly more effective than conventional oxygen electrodes.
Asher, W. J.↗
Determination of Optical Constants of in Bi from Reflectance Measurements
A fall in reflectance was noted from values obtained for a freshly cleaved sample to values obtained after periods of exposure of the surface to air. The decrease in reflectance with increased exposure time is attributed to formation of a surface layer insoluble in Freon or ethyl alcohol; it is assumed to be a tarnish layer. Computer processing was employed to calculate optical constants from reflectance data.
Martin, F. E.↗
Study of the detail content of Apollo orbital photography
The results achieved during a study of the Detail Content of Apollo Orbital Photography are reported. The effect of residual motion smear or image reproduction processes upon the detail content of lunar surface imagery obtained from the orbiting command module are assessed. Data and conclusions obtained from the Apollo 8, 12, 14 and 15 missions are included. For the Apollo 8, 12 and 14 missions, the bracket-mounted Hasselblad camera had no mechanism internal to the camera for motion compensation. If the motion of the command module were left totally uncompensated, these photographs would exhibit a ground smear varying from 12 to 27 meters depending upon the focal length of the lens and the exposure time. During the photographic sequences motion compensation was attempted by firing the attitude control system of the spacecraft at a rate to compensate for the motion relative to the lunar surface. The residual smear occurring in selected frames of imagery was assessed using edge analyses methods to obtain and achieved modulation transfer function (MTF) which was compared to a baseline MTF.
Kinzly, R. E.↗