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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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Subsonic longitudinal characteristics of variable sweep aircraft utilizing free floating wing apex for alleviation of longitudinal stability and supersonic performance problems
Small-diameter, thin-wall tungsten tubing by hot extrusion over floating mandrel
Comparison of two floating aperture data compression schemes
Design and construction of floating element skin friction balances
Steady state and dynamic properties of cylindrical floating ring journal bearing with pressurized lubricant supply, considering turbulent flow and whirl instability
Single crystals of carbides by floating zone technique
Floated shoe close running air seals for supersonic jet engine compressors, discussing axial and radial seals design
Hardware-software provisions for multiple precision floating point arithmetic
Floating zone technique for vanadium carbide single crystal growth
Magnetically centered liquid column float
Paired comparison tests of relative signals detected by capacitive and floating Langmuir probes in turbulent plasmas from 0.2 to 10MHz
Production of aluminum oxide fibers by floating zone fiber drawing technique
Supporting fluid effects in floated inertial instruments, examining cause, frequency, extent and solution
Capacitive and floating Langmuir probes paired comparison measurements of electrostatic potential fluctuations spectrum in steady state turbulent magnetically confined plasma
Paired comparison tests of relative signal detected by capacitive and floating Langmuir probes in steady state turbulent plasma confined in magnetic mirror geometry
Approximations which can be evaluated with precision using floating-point arithmetic are presented. The particular set of approximations thus far developed are for the function TAN and the functions of USASI FORTRAN excepting SQRT and EXPONENTIATION. These approximations are, furthermore, specialized to particular forms which are especially suited to a computer with a small memory, in that all of the approximations can share one general purpose subroutine for the evaluation of a polynomial in the square of the working argument.
A CO2 laser heated, floating zone fiber growth process was developed. The resulting Al2O3 fibers exhibited the high room temperature strengths for large diameter fibers as well as high specific creep rupture strengths observed at 1093 C and 1316 C (2000 F and 2400 F). Single crystal fibers of TiC and Y2O3 were also grown. An optical system was developed to focus four CO2 laser beams onto the surface of a feed rod permitting the formation of highly controllable molten zones. The optical system permitted energy densities and angle of incidence of the beams to be adjusted over wide ranges. This optical system was incorporated into a controlled atmosphere, fiber growth furnace. The two principal advantages of a CO2 laser heat source are that ambient atmospheres may be freely selected to optimize fiber properties and the laser has no inherent temperature limit, so extremely high melting point materials can be melted. Both advantages were demonstrated.
It is shown that an otherwise stable digital control system can be made unstable by signal quantization when the controller operates on floating-point arithmetic. Sufficient conditions of instability are determined, and an example of loss of stability is treated when only one quantizer is operated.