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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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Plastic shoe aids inspection of thin walled stainless steel welded tubing to locate voids or other material defects in critical component equipment. Incorporated in available ultrasonic inspection equipment, it couples the transducer to the tube at desired incident angles.
Aerodynamic and structural data on supersonic decelerators, determining problem areas and voids
Gravity and buoyancy effects on slip ratio, void fraction, flow model and boiling heat transfer
Electron multiplier, incorporated into the camera tube of an ultrasonic imaging system, improves resolution, effectively shields low level circuits, and provides a high level signal input to the television camera. It is effective for inspection of metallic materials for bonds, voids, and homogeneity.
Evaluation of nondestructive methods of testing brazed joints reveals that ultrasonic testing is effective in the detection of nonbonds in diffusion bonded samples. Radiography provides excellent resolutions of void or inclusion defects, and the neutron radiographic technique shows particular advantage for brazing materials containing cadmium.
Study of fluidized-packed bed includes investigation of heat transfer, solids-gas mixing, and elutriation characteristics. A fluidized-packed bed is a system involving the fluidization of small particles in the voids of a packed bed of larger nonfluidized particles.
FASTER computer program modified for tracking neutrons through reactor slabs penetrated by helical voided ducts
Microstructure and void formation in solder connections of components on multilayer boards
Sonic impedance testing detects voids and unbonded regions as small as 1 inch in diameter by 0.03 inch thick. Measurements are made manually or by automatic scanning and the readout is made by meter or recorder.
The Second Workshop on Voltage Breakdown in Electronic Equipment at Low Air Pressure was sponsored by the Jet Propulsion Laboratory, Pasadena, California. It has been three and one-half years since the convening of the first workshop on voltage breakdown. In this interval, gains are evidenced in the progress and sophistication in solving voltage breakdown problems affecting electronic equipment operating at high altitudes or other low air pressure environments. Although space applications predominate the area of concern, other projects such as the SST are becoming increasingly involved with voltage breakdown. High-voltage breakdown in spacecraft continues; however, the incidences of occurrence appear to have decreased in spite of an increase in the number of missions flown. This, it is felt, is due to many project managers now requiring all equipment with voltage in excess of 270-V peak to be designed to operate in the critical pressure region without damage, even though its normal functional environment is sea level pressure and the hard vacuum of space. In addition, designers are becoming more aware of the principle of good high-voltage design by selecting void-free components, proper spacing of conductors, isolating high-voltage circuitry from lower voltage areas, etc. The consensus seems to be that the slight increase in cost to achieve a provable corona-free design is more than offset by the increase in confidence that the equipment will survive accidental loss of vacuum during high-vacuum tests, inadvertent turn on while passing through the critical air-pressure region of earth after launch or outgassing in flight pressurizing the enclosure into the critical pressure region.
Using void regions trailing orbiting bodies to conserve propellant of untethered modules flying in formation with mother spacecraft
Dry and water-saturated sintered fiber metal wick thermal conductivity, obtaining semiempirical correlations for solid and fluid phases and void fraction
Low energy fracture of high strength Al alloys with void nucleating particles, using microprobe fractography
Technique compresses fine ground metallic powder mixture beyond crystal fusion point. Absence of vapor pressure voids and elimination of incongruous effects permit application of technique to large scale fabrication of intermetallic compounds with specific characteristics, e.g., semiconduction, superconduction, or magnetic properties.
Unidirectional fiber composites impact resistance, showing matrix modulus, fabrication process, fiber and void volume ratios and microresidual stress effects
Vacuum impregnation process produces metal-reinforced ceramics with only 3 percent void space volumes. Method may be used to produce metal-reinforced ceramics for high temperature or structural applications such as furnace supports and armor.
Correlation was obtained for determining sorptive capacity of carbon for pure and mixed contaminants under dry and humid conditions at various temperatures. Vacuum desorption rates were investigated for single particles and for sorbent beds. For sorbent beds, rate-determining step is Knudsen diffusion through interparticle voids.
Filament reinforced composite materials have high strength, high stiffness and low density. Tubes fabricated from process described have advantages of having smooth inner and outer surfaces, lower dimensional variation than tolerances set for extruded aluminum tubing and void free composites.