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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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At least 703 records · Page 39

Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

Gibbons, D. F.↗

Stand-alone development system using a KIM-1 microcomputer module

A small microprocessor-based system designed to: contain all or most of the interface hardware, designed to be easy to access and modify the hardware, to be capable of being strapped to the seat of a small general aviation aircraft, and to be independent of the aircraft power system is described. The system is used to develop a low cost Loran C sensor processor, but is designed such that the Loran interface boards may be removed and other hardware interfaces inserted into the same connectors. This flexibility is achieved through memory-mapping techniques into the microprocessor.

Nickum, J. D.↗

Test report for twinax cable (Rockwell type MB0150-051)

A controlled impedance twisted pair shielded cable was tested to determine the frequency response and effects of mismatched termination. It was found that a long length of this cable, about 100 feet, exhibited a frequency sensitive attenuation roll-off greater than 1.5 db down at 5 MHz. It was also determined that improper termination resulted in losses of 1/2 to 1 db within the frequency range of 200 KHz to greater than 1-1/2 MHz. The test results indicate a possible problem where mismatched connectors are used in video signal cables.

Doland, G. D.↗

ATS-6 flight accelerometers

Five accelerometers mounted near the adapter base of the Titan 3-C launch vehicle and three on the hub of the ATS-F spacecraft provided (1) data for verifying basic spacecraft mode shapes and frequencies during powered flight while attached to the launch vehicle; (2) failure mode detection and diagnostic information on in-flight anomalies; and (3) data to be used in the design of future spacecraft to be flown on the Titan 3-C. Because data from the instruments mounted on the spacecraft hub passed through an in-flight disconnect at the separation plane between the transtage and ATS-F, the moment this connector was broken, the signal to the telemetry system showed a step function change. By monitoring these telemetry traces on the ground at appropriate times during flight sequences, a positive indication of spacecraft separation was obtained. Flight data showing dynamic response at spacecraft launch vehicle interface and at the top of ATS spacecraft during significant launch events are presented in tables.

Mattson, R.↗

Remotely controlled latch

Mechanism engages and disengages parallel plates carrying couplings and connectors. Designed to lock items in place for handling, storage, or processing under remote control, mechanism has fail-safe feature which does not allow plates to separate completely unless both are supported.

Barnett, C. J.↗

Cryogenic seal for instrument wires

Seal allows electrical wires to pass directly from sensors inside of liquid nitrogen storage vessel to outside instruments. No splices or connectors are required, so errors created by contact resistance are avoided. With method, measurements with highly sensitive instrumentation are made with greater accuracy.

Massey, H. V.↗

Repairing flat cables

Simple procedure avoids costly repairs. Cable insulation flaps are cut and peeled back to expose conductor fractures. Insulation layers of decreasing size allow cable to flex without overstressing mended connectors.

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Electroexplosive device

An electroexplosive device is presented which employs a header having contact pins hermetically sealed with glass passing through from a connector end of the header to a cavity filled with a shunt layer of a new nonlinear resistive composition and a heat-sink layer of a new dielectric composition having good thermal conductivity and capacity. The nonlinear resistive layer and the heat-sink layer are prepared from materials by mixing with a low temperature polymerizing resin. The resin is dissolved in a suitable solvent and later evaporated. The resultant solid composite is ground into a powder, press formed into the header and cured (polymerized) at about 250 to 300 F.

Menichelli, V. J.↗

Spacelab payload accommodation handbook. Appendix A: Avionics interface definition

The Spacelab side of the electrical interface between Spacelab subsystem equipment and experiments is presented. The electrical hardware which interfaces with the experiments is defined and the signal/load characteristics are stated. Major subsystems considered include: electrical power and distribution; command and data management subsystem; orbiter avionics via dedicated connectors of Spacelab; and electrical ground support equipment.

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Acoustic scattering by circular cylinders of various aspect ratios

The effects of acoustic scattering on the useful frequency range of pressure gradient microphones were investigated experimentally between ka values of 0.407 and 4.232 using two circular cylindrical models (L/D = 0.5 and 0.25) having a 25 cm outside diameter. Small condenser microphones, attached to preamplifiers by flexible connectors, were installed from inside the cylindrical bodies, and flush mounted on the exterior surface of the cylinders. A 38 cm diameter woofer in a large speaker enclosure was used as the sound source. Surface pressure augmentation and phase differences were computed from measured data for various sound wave incidence angles. Results are graphically compared with theoretical predictions supplied by NASA for ka = 0.407, 2.288, and 4.232. All other results are tabulated in the appendices. With minor exceptions, the experimentally determined pressure augmentations agreed within 0.75 dB with theoretical predictions. The agreement for relative phase angles was within 5 percent without any exceptions. Scattering parameter variations with ka and L/D ratio, as computed from experimental data, are also presented.

Maciulaitis, A.↗

Single Fiber Star Couplers

An ion exchange process was developed and used in the fabrication of state-of-the-art planar star couplers for distribution of optical radiation between optical fibers. An 8 x 8 planar transmission star coupler was packaged for evaluation purposes with sixteen fiber connectors and sixteen pigtails. Likewise a transmission star coupler and an eight-port reflection star coupler with eight-fiber ribbons rigidly attached to these couplers, and a planar coupler with silicon guides and a parallel channel guide with pigtails were also fabricated. Optical measurements of the transmission star couplers are included with a description of the manufacturing process.

Asawa, C. K.↗

Prosthesis coupling

A coupling for use in an apparatus for connecting a prosthesis to the bone of a stump of an amputated limb is described which permits a bio-compatible carbon sleeve forming a part of the prosthesis connector to float so as to prevent disturbing the skin seal around the carbon sleeve. The coupling includes a flexible member interposed between a socket that is inserted within an intermedullary cavity of the bone and the sleeve. A lock pin is carried by the prosthesis and has a stem portion which is adapted to be coaxially disposed and slideably within the tubular female socket for securing the prosthesis to the stump. The skin around the percutaneous carbon sleeve is able to move as a result of the flexing coupling so as to reduce stresses caused by changes in the stump shape and/or movement between the bone and the flesh portion of the stump.

Reswick, J. B.↗

Test evaluation of space station ECLSS maintenance concepts

The Space Station Prototype (SSP) Environmental Control and Life Support System (ECLSS) hardware was designed and built to be maintainable by the flight crew. To achieve this goal, subsystems were designed for ease of component removal and installation, which included accessibility to component fasteners and connectors, adequate tool clearance, minimum fluid loss during changeout, positive capture of loose parts during changeout, replacement by one crewman, and protection of adjacent parts during maintenance. During testing of this hardware, many day-to-day problems arose which allowed the evaluation of the maintenance concepts under actual maintenance conditions. This paper briefly discusses the maintenance objectives of the hardware design. Specific maintenance designs and their test evaluations are discussed. A removable cartridge valve concept for liquid line components and threaded mechanical fittings and V-band couplings for gaseous line components are critiqued. Other maintenance devices are also evaluated.

Reysa, R. P.↗

Orbital demonstration - The prelude to large operational structures in space

The paper surveys three specific large space structures which have been analyzed to determine the technology needed to achieve a fully operational system. These are the multipurpose platforms; satellite power systems, and a deployable antenna. Further attention is also given to those technology needs which can be satisfied by ground based technology (simulation), such as payload carrier modification or design, platform element connectors and fittings, data compression and storage equipment, man-machine interface and productivity assessment, and astronaut aids. Also covered are those technology and performance parameters which require demonstration in orbit.

Hagler, T.↗

Mechanical end joint for structural columns

Connector for tubular struts permits construction of lightweight frames without tools or assembly equipment. Two main components are node fitting and strut element. Components are aleaned approximately and pushed together. Design accommodates reasonable axial and rotational misalignment of nodes and struts. Also, individual columns can be inserted into receptacle and given slight push by operator, trigger pins release ratchet, allowing energy stored in springs to rotate screw into nut in receptacle.

Bush, H. G.↗

Release mechanism for releasing and reattaching experiments on the Space Shuttle

The release mechanism (REM) unlatches an experiment so that it can be moved about inside and outside the shuttle bay by the remote manipulator system (RMS), and then reattaches it to the REM base. Operated from the crew compartment after the RMS has been attached to the experiment, the REM releases the experiment by an electric motor driving a gear train and linkage which extracts four pins from holes in four plates. Electrical connectors on the REM are disengaged by the mechanical action of the structural pins retracting from the plates. When the REM releases the experiment, an unlatched indicator is actuated in the crew compartment, and then the experiment can be moved by using the RMS. To reattach the experiment to the REM, the RMS places the experiment with REM attachment angles against the flat, smooth surface of the REM; then the RMS moves the experiment into position for latchup. Actuation of an electric motor drives the four pins into the four holes in the plates. When fully latched, a switch actuated by the motion of the linkage, shuts the electric motor off and gives an indication to the crew compartment that the REM is latched.

Clark, A. V.↗

Pogo summary report main propulsion test static firings 1-7 for shuttle development flight instrumentation

Problems concerning the shuttle main propulsion system Polar Orbit Geophysical Observatory (POGO) instrumentation and the actions taken to correct them are summarized. Investigations and analyses appear to be providing solutions to correct the majority of questionable measurements. Corrective action in the handling of cables and connectors should increase the POGO measurement quality. Unacceptable levels of very low frequency noise and data level shifts may be related to test stand grounding configuration, but further investigation is required.

Haddick, C. M., Jr.↗

High-Density Terminal Box for Testing Wire Harness

Compact terminal box provides access to complex wiring harnesses for testing. Box accommodates more than twice as many wires as previous boxes. Box takes in wires via cable connectors and distributes them to contacts on box face. Instead of separate insulated jacks in metal face panel, box uses pairs of small military-standard metal sockets in precision-drilled plastic panel. Shorting plug provides continuity for wires when not being tested.

Pierce, W. B.↗