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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 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Twisted, multifilament Nb3Sn superconductive ribbon

An experimental study of superconductor stabilization has resulted in the successful application of the concepts of filamentary structure and conductor twist to Nb3Sn ribbon. The Nb3Sn is formed in parallel, helical paths, which are continuous around the ribbon. Short lengths (12-18cm) of 1.27 cm wide superconductive ribbon were produced. The filamentary and twist characteristics are incorporated in the ribbon by means of an inert mask formed on the ribbon surface early in the fabrication process. Diffusion reaction of the niobium and tin is prevented at the filament boundaries. Described are the conductor methods of fabrication, and test results obtained. The technology required to adapt the processes for the production of long lengths of ribbon is available.

Coles, W. D.↗
NASA NTRS1971

Electron microscopy and diffraction of layered, superconducting intercalation complexes.

Several layered, transition metal dichalcogenide intercalation complexes with unique superconducting properties have been examined by high-resolution electron microscopy and electron diffraction. Details of the crystalline lattice and of the lattice imperfections have been directly resolved. The results can be correlated with the available X-ray diffraction and chemical data, and they confirm and extend the postulated models.

Fernandez-Moran, H.↗
NASA NTRS1971

Effect of uniaxial stress on the superconducting transition temperature of monocrystalline Nb3Sn.

Measurements have been made of the stress dependence of the superconducting transition temperature (T sub c) of single crystals of Nb3Sn oriented in the (001) direction. The magnitude of the stress dependence of T sub c is about 1000 times larger than that generally observed for elemental superconductors. The results further imply that below the tetragonal transformation temperature (T sub m), the crystal consists of tetragonal domains with variable orientation of the c axis and that the domain configuration and T sub c depend on the applied stress at T sub m.

Mcevoy, J. P.↗
NASA NTRS1971

Superconducting properties as a function of thickness in NbN films.

Measurement of the superconducting properties of NbN films prepared by a high purity reactive sputtering process. The transition temperature was found to decrease with decreasing film thickness, while in contrast the critical current vs magnetic field was largely independent of film thickness and even slightly increased when the film thickness went down to 100 A. The average resistivity of the NbN films was 1000 microohm-cm.

Gavaler, J. R.↗
NASA NTRS1971

Ultrasonic attenuation in superconducting molybdenum-rhenium alloys.

Investigation of longitudinal sound attenuation in superconducting Mo-Re alloys as a function of temperature, magnetic field, and frequency. Evaporated thin film CdS transducers were used for the measurements at frequencies up to 3 GHz. The normal state attenuation coefficient was found to be proportional to the square of frequency over this frequency range. Measurements in zero magnetic field yielded a value of the energy gap parameter close to the threshold value of 3.56 kTc, appropriate to a weakly coupled dirty limit superconductor.

Ashkin, M.↗
NASA NTRS1972

Superconducting magnetic spectrometer for cosmic ray nuclei.

This paper describes the design, calibration, and operation of a magnetic spectrometer for particle astronomy. The spectrometer consists of a superconducting magnet, optical spark chambers, scintillation detectors, and associated electronics. The instrument has been flown in a balloon gondola to 4.8 g/sq cm residual atmosphere, where it was used to analyze the charge and differential rigidity spectra of primary nuclei from 5 to 100 GeV/c.

Smith, L. H.↗
NASA NTRS1971

The University of Virginia superconducting magnetic suspension and balance facility.

Description of a prototype facility comprising a superconducting magnetic suspension and balance and a supersonic wind tunnel. This facility was developed with the objectives of establishing the feasibility of applying the three-component magnetic balance concept to dynamic stability studies, and investigating design concepts and parameters that are critical for extrapolation to large-scale systems. Many important design and operational aspects, as well as safety considerations, are dictated by the cryogenic nature of this advanced-technology facility. Results of initial tests demonstrate that superconductors can be utilized safely and efficiently for wind-tunnel magnetic suspensions. At the present stage of development of this facility, controlled one-dimensional support of a spherical model has been achieved.

Zapata, R. N.↗
NASA NTRS1971

Data acquisition and reduction for the U. Va. superconducting magnetic suspension and balance facility.

The problems associated with data acquisition and reduction in the University of Virginia superconducting magnetic suspension and balance facility are similar to those in free-flight ranges (or tunnels). The model undergoes a 'Quasi-six-degree-of-freedom' motion which must be monitored both in position and angular orientation from which the aerodynamics must be inferred. The data acquisition problem is made more difficult because geometric constraints prevent direct visual access to the model in the Mach 3 wind tunnel. The methods, accuracies and problems associated with the acquisition of data are discussed.-

Jacobson, I. D.↗
NASA NTRS1970

Data acquisition and reduction for the University of Virginia superconducting magnetic suspension and balance facility

The problems associated with data acquisition and reduction in the U. Va. superconducting magnetic suspension and balance facility are similar to those in free-flight ranges (or tunnels). The model undergoes a quasi-six-degree-of-freedom motion which must be monitored both in position and angular orientation from which the aerodynamics must be inferred. The data acquisition problem is made more difficult because geometric constraints prevent direct visual access to the model in the Mach 3 wind tunnel. The methods, accuracies, and problems associated with the acquisition of data are discussed.

Jacobson, I. D.↗
NASA NTRS1972

Performance of a 12-coil superconducting bumpy torus magnet facility

The bumpy torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 teslas on their axes. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m, and are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Final shakedown tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The facility is now ready for use as a plasma physics research facility. A maximum magnetic field on the magnetic axis of 3.23 teslas was held for a period of more than sixty minutes without a coil normalcy. The design field was 3.00 teslas. The steady-state liquid helium boil-off rate was 87 liters per hour of liquid helium without the coils charged. The coil array was stable when subjected to an impulsive loading, even with the magnets fully charged. When the coils were charged to a maximum magnetic field of 3.35 teslas, the system was driven normal without damage.

Roth, J. R.↗
NASA NTRS1973

The University of Virginia superconducting magnetic suspension and balance facility

A prototype facility comprising a superconducting magnetic suspension and balance and a supersonic wind tunnel was developed with the objectives of (1) establishing the feasibility of applying the 3-component magnetic balance concept to dynamic stability studies, and (2) investigating design concepts and parameters that are critical for extrapolation to large-scale systems. Many important design and operational aspects as well as safety considerations are dictated by the cryogenic nature of this advanced-technology facility. Results of initial tests demonstrate that super-conductors can be utilized safely and efficiently for wind tunnel magnetic suspensions. At the present stage of development of this facility, controlled one-dimensional support of a spherical model was achieved.

Zapata, R. N.↗
NASA NTRS1973

Data acquisition and reduction for the University of Virginia superconducting magnetic suspension and balance facility

The problems associated with data acquisition and reduction in the U.Va. superconducting magnetic suspension and balance facility are similar to those in free-flight ranges (or tunnels). The model undergoes a Quasi-six-degree of freedom motion which must be monitored both in position and angular orientation problem is made more difficult because geometric constraints prevent direct visual access to the model in the Mach 3 wind tunnel. The methods, accuracies and problems associated with the acquisition of data are discussed.

Jacobson, I. D.↗
NASA NTRS1973

Characteristics and performance of a superconducting bumpy-torus magnet facility for plasma research

The NASA Lewis bumpy-torus facility consists of 12 superconducting coils, each 19 cm i.d. and capable of 3.0 T on its axis. The coils are equally spaced around a toroidal array with a major diameter of 1.52 m; they are mounted with the major axis of the torus vertical in a single vacuum tank 2.6 m in diameter. Tests of the facility mapped out its magnetic, cryogenic, vacuum, mechanical, and electrical performance. The design value of the maximum magnetic field on the magnetic axis, 3.0 T, was reached and exceeded. A maximum magnetic field of 3.23 T was held for a period of 60 minutes. When the coils were charged to a maximum magnetic field of 3.35 T, the coil system went normal without apparent damage or degradation of performance.

Roth, J. R.↗
NASA NTRS1965

Superconductive magnetic-field-trapping device

An apparatus which enables the establishment of a magnetic field in air that has the same intensity as the ones in ferromagnetic materials is described. The apparatus is comprised of a core of ferromagnetic material and is surrounded by a cylinder made of a material that has superconducting properties when cooled below a critical temperature. A method is provided for producing a magnetic field through the ferromagnetic core. The core can also be split and pulled apart when it is required that the center of the cavity be left empty.

Hildebrandt, A. F.↗
NASA NTRS1972

One-dimensional periodic superconducting weak-link systems.

The solution of the one-dimensional Ginzburg-Landau equation is presented for the case of a linear, periodic, superconducting weak-link system. With respect to currents below a critical value, four solutions for the spatially dependent order parameter are obtained.

Blackburn, J. A.↗
NASA NTRS1973

Superconducting resonators and devices.

The high-frequency properties of superconductors are reviewed, including the London, Pippard, and Mattis-Bardeen surface impedance, and techniques for measuring and separating losses are discussed. Residual resistance mechanisms are described and evaluated, including high field effects. The state of knowledge is shown to be adequate for engineering design. Applications of superconducting resonators and lines to filters, tuners, oscillators, amplifiers and mixers, transmission lines, antennas, optical and radiation detection, and materials research are discussed.

Hartwig, W. H.↗