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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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Combined conduction and radiation transfer equations solutions for absorbing-emitting gas, obtaining slip coefficient for diffusion solution correct boundary condition
Markov process for time to cycle slip in first and second order phase lock loops
Performance characteristics of liquid and solid lubricants for contacts of miniature slip-ring capsules
Eliminating insulating deposits on precious metal contacts in stabilized platform slip ring capsules
Liquid gallium slip rings for transferring electrical power across rotating joints
Slip flow of nitrogen gas through long circular tubes, measuring mass flow, pressure drop and cross sectional velocity profiles
Recursive differential equation for moments of time-to-cycle slip in first and second order phase lock loops
Rotating fluid coupler, consisting of rotor and housing made of aluminum, that is concentric with electrical slip-ring assembly, transfers cooling fluid to instrumentation undergoing environmental tests on rotating platform. Rotating fluid coupler permits unlimited platform revolutions and eliminates danger of lines being pulled loose from supplies.
Freeze casting of metal ceramic and refractory compound powders into plastic slips
Development of liquid metal slip ring to transfer power between rotating satellite parts
Effect of velocity slip at porous boundary on performance of incompressible porous bearing
Development of slip ring assembly with inner and outer peripheral surfaces used as electrical contacts for brushes
Magnetic head/tape interface problems of satellite data storage tape recording systems, and minimizing stick-slip phenomena
Synergistic effects of slip ring-brush design and fabrication for vacuum application determined by friction, wear, electrical noise, and dielectric strength data
Slip vs static error offset for first and passive second order phase locked loop as function of signal to noise ratio via computer simulation
Slip line deformation of ordered and disordered Cu-Au intermetallic single crystals from microstrain and electron micrographic studies
The design, fabrication, and testing of four power slip rings for synchronous orbit application are considered. Environmental and instrumentation systems necessary for monitoring electrical noise, friction, and brush wear in air and at less than 5 X 10 to the minus 8th power torr were developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite were employed on rings of coin silver and rhodium plate. These four contact combinations were tested during ambient condition run-in at 150 and a humidity sequence at 0.1. The first nine months of a two year vacuum test performed at 0.1 rpm were completed.
A program is being conducted for testing of slip rings for synchronous orbit application. Instrumentation systems necessary for monitoring electrical noise, friction, and brush wear at atmospheric pressure and at less than 50 ntorr have been developed. A multiplex scheme necessary for the simultaneous recording of brush displacement, friction, and electrical noise has also been developed. Composite brushes consisting of silver-molybdenum disulfide-graphite and silver-niobium diselenide-graphite have been employed on rings of coin silver and rhodium plate. Four contact combinations have been tested during an ambient condition run-in at 150 rpm and a humidity sequence at 0.1 rpm. The first six months of the two year vacuum test at 0.1 rpm have been completed. Electrical noise, friction and brush wear data recorded during these periods have been analyzed.