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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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Numerical residual perturbation solution for prediction of satellite position in restricted three-body problem
Computer subroutine for introducing fixed and variable delay functions in analog problems
Astrophysics problems covering exploration of atmosphere, ionosphere, radiation, solar emission, geomagnetic and interplanetary magnetic fields
The discrete frequency sound produced by the flow of air at low subsonic speeds over a deep cavity was investigated. A long aspect ratio rectangular cavity with a leading edge overhang that cut off of the cavity opening was placed flush with the top surface of a wind tunnel. The approach flow velocity was maintained at 50 m/s for the benchmark problem although results are also presented for other conditions. Boundary layer measurements conducted with a single element hotwire anemometer indicated that the boundary layer thickness just upstream of the cavity was equal to 17 mm. Sound pressure level measurements were made at three locations in the cavity: the center of the leading edge wall, the center of the cavity floor, and the center of the trailing edge wall. Three discrete tones were measured at all three locations with corresponding Strouhal numbers (based on cavity opening length and approach flow velocity) equal to 0.24, 0.26, and 0.41. The amplitudes of each tone were approximately equal at each measurement location in the cavity. Measurements made at other approach flow conditions indicated that the approach flow velocity and the boundary layer thickness affected the frequency characteristics of the discrete tones.
This paper describes a simple method for integrating certain kinds of combinatorial sub-problem solvers within a general purpose planner/scheduler framework that demonstrably increases solution speed and quality.
Although the general class of most scheduling problems is NP-hard, in practice, domain-specific.
Our work focuses upon development of techniques for choosing among a set of alternatives in the presence of incomplete information and varying costs of acquiring information.
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This dataset accompanies the publication "GenASiS: General Astrophysical Simulation System. II. Self-gravitating Baryonic Matter." This dataset contains simulation outputs from GenASiS described in the Appendix of that publication.
Spacecraft guidance - vehicle motion in moon and earth gravitational fields
Image orthicon and vidicon television camera tubes
Nonparametric discrimination theory and mathematical model for electronic component screening
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Although the derivation is concerned with solutions for plane regions with prescribed boundary values, the approach presented could by easily generalized to higher dimensions. The initial-value method is derived by a combination of invariant imbedding techniques and the Fredholm integral equation method of representation of the potential as a function of a dilayer distribution on the boundary of the region in question.
Description of an approach to computer programming which tries to minimize the time required for retranslation from the computer language into the language of the original process. A notion of a programmable network is introduced which allows the abstract machines that are a model of the processes in the user's mind to be put into a rigorous and simple form. Each process is then modeled as a particular finite-state machine, a circulating page loose system being employed as an architecture for implementing these finite-state machines. An experiment is discussed in which the use of abstract machines as a language for modeling processes, in conjunction with the use of a self-organizing computer, decreases user effort, eliminates the need for compilation, facilitates debugging, and decreases computer time.
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