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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS2007

Freeze Tape Casting of Functionally Graded Porous Ceramics

Freeze tape casting is a means of making preforms of ceramic sheets that, upon subsequent completion of fabrication processing, can have anisotropic and/or functionally graded properties that notably include aligned and graded porosity. Freeze tape casting was developed to enable optimization of the microstructures of porous ceramic components for use as solid oxide electrodes in fuel cells: Through alignment and grading of pores, one can tailor surface areas and diffusion channels for flows of gas and liquid species involved in fuel-cell reactions. Freeze tape casting offers similar benefits for fabrication of optimally porous ceramics for use as catalysts, gas sensors, and filters.

Sofie, Stephen W.↗
NASA NTRS2003

Software Computes Tape-Casting Parameters

Tcast2 is a FORTRAN computer program that accelerates the setup of a process in which a slurry containing metal particles and a polymeric binder is cast, to a thickness regulated by a doctor blade, onto fibers wound on a rotating drum to make a green precursor of a metal-matrix/fiber composite tape. Before Tcast2, setup parameters were determined by trial and error in time-consuming multiple iterations of the process. In Tcast2, the fiber architecture in the final composite is expressed in terms of the lateral distance between fibers and the thickness-wise distance between fibers in adjacent plies. The lateral distance is controlled via the manner of winding. The interply spacing is controlled via the characteristics of the slurry and the doctor-blade height. When a new combination of fibers and slurry is first cast and dried to a green tape, the shrinkage from the wet to the green condition and a few other key parameters of the green tape are measured. These parameters are provided as input to Tcast2, which uses them to compute the doctor-blade height and fiber spacings needed to obtain the desired fiber architecture and fiber volume fraction in the final composite.

deGroh, Henry C., III↗
NASA NTRS2012

Deployment Analysis of a Simple Tape-Spring Hinge Using Probabilistic Methods

Acceptance of new deployable structures architectures and concepts requires validated design methods to minimize the expense involved with technology validation flight testing. Deployable concepts for large lightweight spacecraft include booms, antennae, and masts. This paper explores the implementation of probabilistic methods in the design process for the deployment of a strain-energy mechanism, specifically a simple tape-spring hinge. Strain-energy mechanisms are attractive for deployment in very lightweight systems because they do not require the added mass and complexity associated with motors and controllers. However, designers are hesitant to include free deployment, strain-energy mechanisms because of the potential for uncontrolled behavior. In the example presented here, the tapespring cross-sectional dimensions have been varied and a target displacement during deployment has been selected as the design metric. Specifically, the tape-spring should reach the final position in the shortest time with the minimal amount of overshoot and oscillations. Surrogate models have been used to reduce computational expense. Parameter values to achieve the target response have been computed and used to demonstrate the approach. Based on these results, the application of probabilistic methods for design of a tape-spring hinge has shown promise as a means of designing strain-energy components for more complex space concepts.

Lyle, Karen H.↗
NASA NTRS2002

Flow Visualizations in a Packed Bed of Twisted Tapes

A videotape presentation of the flow field in a packed bed of 48 twisted tapes which can be simulated by very thin virtual cylinders has been assembled. The indices of refraction of the oil and the Lucite twisted tapes were closely matched, and the flow was seeded with magnesium oxide particles. Planar laser light projected the flow field in two dimensions both along and transverse to the flow axis. The flow field was three dimensional and complex to describe, yet the most prominent finding was flow threads. It appeared that axial flow spiraled along either within the confines of a virtual cylindrical boundary or within the exterior region, between the tangency points, of the virtual cylinders. Random packing and bed voids created vortices and disrupted the laminar flow but minimized the entrance effects. The flow-pressure drops in the packed bed fell below the Ergun model for porous-media flows. Single-twisted-tape results of Smithberg and Landis (1964) were used to guide the analysis. In appendix A the results of several investigators are scaled to the Ergun model. Further investigations including different geometric configurations, computational fluid dynamic (CFD) gridding, and analysis are required.

Hendricks, R. C.↗
NASA NTRS1966

Magnetic Tape Recording

NASA's contribution to tape recorder technology may appear to lie in such glamorous devices as the tape recorders of the Tiros and Nimbus satellites which receive signals carrying weather information during an orbit around the earth and then transmit those signals back to the ground when the satellite is in view of ground stations. These quite important recording devices are, however, only useful as members of a complex hierarchy of devices all of which participate in the ultimate process of obtaining information from NASA's efforts. Their existence and utility is based on the existence of many more prosaic recording devices which have been involved in the development of such spectacular units.

TAPE RECORDER↗
NASA NTRS1965

Paper tape conversion procedures

Implementation of programs for conversion of paper tape information to IBM 7090/94 magnetic tape, punched cards, and printed page

MAGNETIC TAPE↗
NASA NTRS1994

Storage, Preservation, and Recovery of Magnetic Recording Tape

During the 1970's, a commercial magnetic recording tape fabricated with magnetic oxide particles, and with oxide and backcoat binders made from polyester urethane was being used for spacecraft tape recorders, and which would periodically manifest operational problems such as layer-to-layer adhesion, stick-slip, and shedding of sticky organic materials. These problems were generally associated with periods of high humidity. An experimental study identified that these problems resulted from hydrolysis of the polyester urethane binders.

Magnetic Recording Tape↗
NASA NTRS1997

The Galileo Tape Recorder Rewind Operation Anomaly

On October 10, 1995, the Galileo spacecraft executed a sequence to record two approach images of Jupiter on the spacecraft's tape recorder, rewind the tape, and play back the images at the appropriate data rate consistent with the downlink performance.

flight↗
NASA NTRS1964

Low-cost tape system measures velocity of acceleration

By affixing perforated magnetic recording tape to the falling end of a body, acceleration and velocity were measured. The measurement was made by allowing the tape to pass between a light source and a photoelectric sensor. Data was obtained from a readout device.

Hartenstein, R.↗
NASA NTRS1964

Compact cartridge drives coded tape at constant readout speed

To facilitate storage and repetitive reading of short-program coded tape, a cartridge case, containing mechanical drive and readout assemblies, has been fabricated. The drive transports the tape past a conventional pickup device during the reading function.

Austin, D. C.↗
NASA NTRS1964

JPL Ephemeris Tapes E9510, E9511, and E9512

The first issue of JPL Ephemeris Tapes is described. These tapes carry the positions and velocities of the planets and of the Moon, plus nutations and nutation rates in longitude and obliquity, together with second and fourth modified differences, for the interval December 30, 1949, to January 5, 2000.

Peabody, P. R.↗
NASA NTRS1966

Expandable takeup reel facilitates paper tape removal

Takeup reel receives continuous paper tapes from data recording machines. The roller is recessed to have four longitudinal members about its periphery which can be extended or retracted to change the overall diameter of the assembly to allow easy removal of the tapes.

Westerman, H. E.↗