Mechanical & Fluid Systems

Heart-Pump-Outlet/Cannula Coupling

This coupling is separable, free of leaks, and configured to minimize clotting. A fluid coupling has been developed for use in securing a vascular outflow graft (cannula) to the outlet of a surgically implanted NASA/DeBakey heart assist pump. The design of the coupling can also be adapted to other applications in which it is necessary to join flexible tubes with rigid ones. A joint formed by use of this coupling is separable, yet free of leaks; this is advantageous in that (1) it is necessary to be able to install or remove a pump in accordance with requirements for surgery, sterilization, and pump maintenance, but (2) seepage of blood from an installed pump/cannula joint cannot be tolerated. Moreover, the coupling provides a smooth transition for flow from the pump outlet to the cannula; this feature helps to prevent clotting, which is triggered by flow-surface discontinuities.

Posted in: Mechanics, Briefs

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Surface-Launched Explorers for Reconnaissance/Scouting

Efficiency of robotic exploration would be increased. Small, instrumented, expendable robotic aircraft and projectiles have been proposed for use in scouting for targeted new sites by providing closeup images with ~10-cm resolution, covering large distances ~1 to 10 km quickly and allowing reconnaissance to enable sample return. Denoted microflyers or surface-launched explorers (SLEs), the proposed robotic aircraft and projectiles were conceived especially for use in the exploration of Mars and possibly other distant planets. SLEs could also be adapted to such terrestrial uses as military reconnaissance, exploration of hostile terrain (e.g., volcanoes, steep cliffs, or glaciers), surveying hazardous-waste sites, and searching for victims of earthquakes.

Posted in: Briefs, TSP

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Gear Bearings and Gear-Bearing Transmissions

Planetary transmissions could be simpler, cheaper, and more rigid. Gear bearings are conceptual mechanical components so named because they function as gears and as roller and/or thrust bearings. Gear bearings will be essential components of the next generation of compact, large-mechanical- advantage gear drives.

Posted in: Mechanics, Briefs, TSP

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Linear Dynamometer With Variable Stroke and Frequency

Stroke length and frequency can be adjusted continuously during operation. An improved linear dynamometer has been developed for testing linear alternators that are to be used to convert mechanical power to electrical power in free-piston Stirlingcycle engines. Both the frequency and the length of the stroke of this dynamometer can be varied continuously, even during operation; consequently, the dynamometer can be used to fully map the capabilities of a linear alternator throughout its service envelope (its operational range as defined on a plot of limiting stroke length versus frequency) in a single test.

Posted in: Briefs, TSP

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Study of Turbulent Boundary Layer on the F-15B Airplane

Automated hot-wire anemometry has been demonstrated in flight tests. NASA’s F-15B #836 is a two-seat version of the F-15, which is a high-performance, supersonic, all-weather fighter airplane. The F-15B is used as a test-bed aircraft for a wide variety of flight experiments. In support of this use, a flight-test fixture (FTF) was developed to provide a space for flight experiments in a region with known aerodynamic conditions. The FTF is a fully instrumented test article mounted on the center line of the bottom of the fuselage of an F-15B airplane. The FTF includes an interchangeable experiment panel and is 107 in. (2.72 m) long, 32 in. (0.81 m) high, and 8 in.(20.3 cm) wide, with a 12-in. (30.5-cm) elliptical nose section. The FTF has been used in many flight experiments during the past several years and can be modified to satisfy a variety of research requirements.

Posted in: Mechanics, Briefs, TSP

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Improved Alignment Mechanism for Robotic Drilling

The improved design prevents jamming of an alignment key in an incorrect position. An improved alignment mechanism and mating procedure have been devised for a robotic drilling system in which there is a need to assemble drill stem rods for sampling soils and rocks on a distant planet or asteroid. This mechanism is applicable to systems requiring positive axial alignment between segments. Similar mechanisms could be used on Earth, not only for assembling long drills but also for any system where a series of rods must be robotically assembled, such as in truss construction.

Posted in: Mechanics, Briefs, TSP

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Measuring Volume of Incompressible Liquid in a Rigid Tank

The measurement is unaffected by the shape of the liquid or tank. A technique for measuring the volume of an incompressible liquid in a rigid tank involves measurement of the total volume of gas in those parts of the tank not occupied by the liquid. The volume of liquid is then computed by subtracting V from the total volume of the tank and the associated plumbing.

Posted in: Mechanics, Briefs, TSP

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