Photon statistics for threshold laser light with finite counting time.
Time dependence of second, third and fourth cumulants of light intensity distribution of He-Ne laser operating just below threshold
Chang, R. F.↗
SEARCH · Engineering Papers
Results for “cumulative”
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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Low-cycle fatigue in structural graphite under localized loading.
Cumulative damage effects in structural graphite in tension, using low cycle fatigue loading method
Kachur, V.↗
Mutual gravitational and collisional scattering of bodies in the asteroid belt.
Mutual gravitational and collisional scattering of bodies in asteroid belt, calculating orbital perturbations cumulative effect
Wetherill, G. W.↗
Some analytical and experimental phase-locked loop results for low signal-to-noise ratios.
Phase locked results for low SNRs pertaining to phase errors probability, cumulative and variance distribution, including time intervals between cycle-slipping
Charles, F. J.↗
Upper limits to the micron and submicron particle flux at satellite altitudes.
Micron and submicron particle cumulative flux upper limits in satellite micrometeoroid environment of Gemini 12
Brownlee, D. E.↗
Fatigue crack propagation and strain cycling properties.
Fatigue crack propagation caused by cumulative damage due to strain cycling at crack tip, relating resistance to cyclic ductility
Lehr, K. R.↗
Mariner IV and OGO III - Recent measurements of picogram dust particle flux in interplanetary and cislunar space.
Cumulative flux of interplanetary and cislunar space dust particles by Mariner 4 and OGO 3 spacecraft, noting particle impact rate
Alexander, W. M.↗
Solar array degradation due to meteoroid impacts during extended planetary missions
Power loss due to cumulative meteoroid impacts on solar cells during extended planetary missions, investigating hypervelocity particle impacts into glass
Richardson, A. J.↗
Fiscal output data produce versatile graphic-numeric charts
Refined computerized plotting system produces low-cost graphic-numeric charts that illustrate fiscal data on monthly incremental or cumulative basis, or both. Output is in the form of hard copy or microfilm, or visual-aid transparencies prepared from hard copy for rapid management status presentations.
Powell, R. W.↗
Meteoroid activity on the lunar surface from the Surveyor III sample examination
Lunar surface meteoroid activity from Surveyor 3 sample examination, comparing with predictions by cumulative-flux and near-earth models
Cour-Palais, B. G.↗
Image resolution: Its significance in a wildland area
The information content of simulated space photos as a function of various levels of image resolution was determined by identifying major vegetation-terrain types in a series of images purposely degraded optically to different levels of ground resolution resolvable distance. Comparison of cumulative interpretation results with actual ground truth data indicates that although there is definite decrease in interpretability as ground resolvable distance increases, some valuable information is gained by using even the poorest aerial photography. Developed is the importance of shape and texture for correct identification of broadleaf or coniferous vegetation types and the relative unimportance of shape and texture for the recognition of grassland, water bodies, and nonvegetated areas. Imagery must have a ground resolvable distance of at least 50 feet to correctly discriminate between primary types of woody vegetation.
Lauer, D. T.↗
Simulation of flight maneuver-load distributions by utilizing stationary, non-Gaussian random load histories
Random numbers were generated with the aid of a digital computer and transformed such that the probability density function of a discrete random load history composed of these random numbers had one of the following non-Gaussian distributions: Poisson, binomial, log-normal, Weibull, and exponential. The resulting random load histories were analyzed to determine their peak statistics and were compared with cumulative peak maneuver-load distributions for fighter and transport aircraft in flight.
Leybold, H. A.↗
Earth resources research data facility R and D file. Volume 1: Documentary data
Cumulative listings of the R and D file data are presented. All Earth Resources Program information available at the Manned Spacecraft Center is in Vol. 1. Sensor data collected during flights over NASA test sites and from missions flown by subcontractors supporting the Earth Resources Survey Program are included in Vol. 2.
Source record↗
Meteoroid activity on the lunar surface from the Surveyor 3 sample examination
The Surveyor 3 television camera shroud and polished aluminum tube, retrieved as a result of the Apollo 12 mission after 2-1/2 years on the lunar surface, were examined at the NASA Manned Spacecraft Center for evidence of meteoroid impact. The results of this examination were compared with other estimates of the meteoroid flux in the lunar vicinity and are shown to be in good agreement with the Lunar Orbiter penetration rates. In addition, the relationship between a derived lunar surface meteoroid cumulative-flux model and the comparable near-earth model is discussed in the light of theoretical predictions. It is shown that the effect of the gravitational field of the earth on the near-earth environment was greater than previously predicted. The implication is that the average meteoroid velocity relative to the earth is probably 17 km/s. The many low velocity impacts on the Surveyor 3 camera and tube are shown to be of lunar surface origin and to be primarily the result of rocket exhaust interaction.
Cour-Palais, B. G.↗
Fundamental Mechanisms of Tensile Fracture in Aluminum Sheet Unidirectionally Reinforced with Boron Filament
Results are presented from an experimental research effort to gain a more complete understanding of the physics of tensile fracture in unidirectionally reinforced B-Al composite sheet. By varying the degree of filament degradation resulting from fabrication, composite specimens were produced which failed in tension by the cumulative mode, the noncumulative mode, or by any desired combination of the two modes. Radiographic and acoustic emission techniques were combined to identify and physically describe a previously unrecognized fundamental fracture mechanism which was responsible for the noncumulative mode. The tensile strength of the composite was found to be severely limited by the noncumulative mechanism which involved the initiation and sustenance of a chain reaction of filament fractures at a relatively low stress level followed by ductile fracture of the matrix. The minimum average filament stress required for initiation of the fracture mechanism was shown to be approximately 170 ksi, and appeared to be independent of filament diameter, number of filament layers, and the identity of the matrix alloy.
Herring, H. W.↗
A Markov chain technique for determining the acquisition behavior of a digital tracking loop
An iterative procedure is presented for determining the acquisition behavior of discrete or digital implementations of a tracking loop. The technique is based on the theory of Markov chains and provides the cumulative probability of acquisition in the loop as a function of time in the presence of noise and a given set of initial condition probabilities. A digital second-order tracking loop to be used in the Viking command receiver for continuous tracking of the command subcarrier phase was analyzed using this technique, and the results agree closely with experimental data.
Chadwick, H. D.↗
Improved neutron activation prediction code system development
Two integrated neutron activation prediction code systems have been developed by modifying and integrating existing computer programs to perform the necessary computations to determine neutron induced activation gamma ray doses and dose rates in complex geometries. Each of the two systems is comprised of three computational modules. The first program module computes the spatial and energy distribution of the neutron flux from an input source and prepares input data for the second program which performs the reaction rate, decay chain and activation gamma source calculations. A third module then accepts input prepared by the second program to compute the cumulative gamma doses and/or dose rates at specified detector locations in complex, three-dimensional geometries.
Saqui, R. M.↗
Statistical analysis of landing contact conditions for three lifting body research vehicles
The landing contact conditions for the HL-10, M2-F2/F3, and the X-24A lifting body vehicles are analyzed statistically for 81 landings. The landing contact parameters analyzed are true airspeed, peak normal acceleration at the center of gravity, roll angle, and roll velocity. Ground measurement parameters analyzed are lateral and longitudinal distance from intended touchdown, lateral distance from touchdown to full stop, and rollout distance. The results are presented in the form of histograms for frequency distributions and cumulative frequency distribution probability curves with a Pearson Type 3 curve fit for extrapolation purposes.
Larson, R. R.↗