DOE Office of Scientific and Technical Information (OSTI.GOV)

Lombardo, v.; Barzi, E.; Turrioni, D.

Superconducting magnets with magnetic fields above 20 T will be needed for a Muon Collider and possible LHC energy upgrade. This field level exceeds the possibilities of traditional Low Temperature Superconductors (LTS) such as Nb{sub 3}Sn and Nb{sub 3}Al. Presently the use of high field high temperature superconductors (HTS) is the only option available for achieving such field levels. Commercially available YBCO comes in tapes and shows noticeable anisotropy with respect to field orientation, which needs to be accounted for during magnet design. In the present work, critical current test results are presented for YBCO tape manufactured by Bruker. Shortmore » sample measurements results are presented up to 14 T, assessing the level of anisotropy as a function of field, field orientation and operating temperature.« less

Pulsed laser deposition of thick BaHfO3-doped YBa2Cu307-δ films on highly alloyed textured Ni-W tapes

NASA Astrophysics Data System (ADS)

Sieger, M.; Hänisch, J.; Iida, K.; Gaitzsch, U.; Rodig, C.; Schultz, L.; Holzapfel, B.; Hühne, R.

2014-05-01

YBa2Cu3O7-δ (YBCO) films with a thickness of up to 3 μm containing nano-sized BaHfO3 (BHO) have been grown on Y2O3/Y-stabilized ZrO2/CeO2 buffered Ni-9at% W tapes by pulsed laser deposition (PLD). Structural characterization by means of X-ray diffraction confirmed that the YBCO layer grew epitaxial. A superconducting transition temperature Tc of about 89 K with a transition width of 1 K was determined, decreasing with increasing BHO content. Critical current density in self-field and at 0.3 T increased with increasing dopant level.

Multi-Aperture Shower Design for the Improvement of the Transverse Uniformity of MOCVD-Derived GdYBCO Films

PubMed Central

Zhao, Ruipeng; Liu, Qing; Xia, Yudong; Zhang, Fei; Lu, Yuming; Cai, Chuanbing; Tao, Bowan; Li, Yanrong

2017-01-01

A multi-aperture shower design is reported to improve the transverse uniformity of GdYBCO superconducting films on the template of sputtered-LaMnO3/epitaxial-MgO/IBAD-MgO/solution deposition planarization (SDP)-Y2O3-buffered Hastelloy tapes. The GdYBCO films were prepared by the metal organic chemical vapor deposition (MOCVD) process. The transverse uniformities of structure, morphology, thickness, and performance were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), step profiler, and the standard four-probe method using the criteria of 1 μV/cm, respectively. Through adopting the multi-aperture shower instead of the slit shower, measurement by step profiler revealed that the thickness difference between the middle and the edges based on the slit shower design was well eliminated. Characterization by SEM showed that a GdYBCO film with a smooth surface was successfully prepared. Moreover, the transport critical current density (Jc) of its middle and edge positions at 77 K and self-field were found to be over 5 MA/cm2 through adopting the micro-bridge four-probe method. PMID:28914793

The Fabrication of (bismuth, LEAD)(2) STRONTIUM(2) CALCIUM(2) COPPER(3) Oxygen(x) Superconductor in Bulk and Tape Forms

NASA Astrophysics Data System (ADS)

Lim, Hanjin

High-T_{rm c}<=ad doped rm Bi_2Sr_2Ca_2Cu _2Cu_3O_{x} (BSCCO 2223) superconductor bulk materials were prepared using conventional powder metallurgy techniques, which were made from precursors having different histories. The ease of formation of superconducting phases was highly dependent on the processing of primitive powder. With the three -powder process that combines three kinds of calcined precursor powders, the formation of the BSCCO superconductor was accelerated and the amount of the secondary phase (e.g., Ca_2CuO_3) was reduced. The critical transition temperature (T _{rm c}) of the superconductor from the three-powder process is higher than that from the one-powder process. In lead-doped BSCCO 2223, positron trapping and annihilation evidently occur in the open BiO double layers rather than in the superconducting CuO_2 layers of the structure. Both positron annihilation parameters (tau_1, tau _2, overlinetau) and Doppler parameters (P, W, P/W) were insensitive to the superconducting transition in this material. This is quite opposite to the case of YBCO and Dy doped YBCO where positron annihilation is sensitive to the superconducting transition. High-T_{rm c} BSCCO superconducting tapes were fabricated using the powder -in-tube (PIT) method that includes heat treatments as well as mechanical processing such as drawing, rolling, and pressing. The highest critical current densities (J _{rm c}) at 5 and 77 K were 5.12 times 10^5 A/cm^2 and 1.77 times 10^4 A/cm^2 , respectively, for the tape sample which was solid state processed at 840^circC with three short sintering steps. J_{ rm c} values at 5 and 77 K of tape samples were 1 and 2 orders of magnitude higher than those of bulk samples, respectively. The preferred orientations of the BSCCO 2212 phase in the tape samples were basal and (1 1 13) textures; for the BSCCO 2223 phase preferred orientations were also basal and (1 1 19) textures. By taking the ratios of the texture coefficients (TCs) for (0 0 1) and (1 1 0) reflections, one can describe the strength of the basal texture for each superconducting phase in both bulk and tape. From these ratios one can say that the best basal texture for the tape BSCCO 2212 was produced by the procedure which included partial melting at 850^circ C for 0.3 h. The best treatment for BSCCO 2223 was the tape sample with solid state processing at 840 ^circC in 10% oxygen.

Electronic State Distributions of YBa2Cu3O7-x Laser Ablated Plumes

DTIC Science & Technology

2008-09-01

deposited on buffered metal substrates using gas phase techniques such as pulsed laser deposition (PLD) or metal -oxide chem- ical vapor deposition...along the desired current direction. This grain orientation has been successfully achieved by depositing YBCO on a metal tape substrate coated with a...Reeves, K. Lenseth, and V. Selvamanickam. “Texture Development and Superconducting Properties of YBCO Thick Films Deposited on Buffered Metal Substrates

Temporal resistance variation of the second generation HTS tape during superconducting-to-normal state transition.

PubMed

Malginov, Vladimir A; Malginov, Andrey V; Fleishman, Leonid S

2013-01-01

The quench process in high-temperature superconducting (HTS) wires plays an important role in superconducting power devices, such as fault current limiters, magnets, cables, etc. The superconducting device should survive after the overheating due to quench. We studied the evolution of the resistance of the YBCO tape wire during the quench process with 1 ms time resolution for various excitation voltages. The resistive normal zone was found to be located in a domain of about 1-4 cm long. The normal state nucleation begins in 40-60 ms after voltage is applied across the HTS tape. In subsequent 200-300 ms other normal state regions appear. The normal domain heating continues in the following 5-10s that results in a factor of 2-3 increase of its resistance. Formation of the normal domain during the quench process follows the same stages for different excitation voltages. Characteristic domain sizes, lifetimes and temperatures are determined for all stages.

AC loss in YBCO coated conductors at high dB/dt measured using a spinning magnet calorimeter (stator testbed environment)

NASA Astrophysics Data System (ADS)

Murphy, J. P.; Gheorghiu, N. N.; Bullard, T.; Haugan, T.; Sumption, M. D.; Majoros, M.; Collings, E. W.

2017-09-01

A new facility for the measurement of AC loss in superconductors at high dB/dt has been developed. The test device has a spinning rotor consisting of permanent magnets arranged in a Halbach array; the sample, positioned outside of this, is exposed to a time varying AC field with a peak radial field of 0.566 T. At a rotor speed of 3600 RPM the frequency of the AC field is 240 Hz, the radial dB/dt is 543 T/s and the tangential dB/dt is 249 T/s. Loss is measured using nitrogen boiloff from a double wall calorimeter feeding a gas flow meter. The system is calibrated using power from a known resistor. YBCO tape losses were measured in the new device and compared to the results from a solenoidal magnet AC loss system measurement of the same samples (in this latter case measurements were limited to a field of amplitude 0.1 T and a dB/dt of 100 T/s). Solenoidal magnet system AC loss measurements taken on a YBCO sample agreed with the Brandt loss expression associated with a 0-0.1 T Ic of 128 A. Subsequently, losses for two more YBCO tapes nominally identical to the first were individually measured in this spinning magnet calorimeter (SMC) machine with a Bmax of 0.566 T and dB/dt of up to 272 T/s. The losses, compared to a simplified version of the Brandt expression, were consistent with the average Ic expected for the tape in the 0-0.5 T range at 77 K. The eddy current contribution was consistent with a 77 K residual resistance ratio, RR, of 4.0. The SMC results for these samples agreed to within 5%. Good agreement was also obtained between the results of the SMC AC loss measurement and the solenoidal magnet AC loss measurement on the same samples.

Fatigue tests of YBCO coated conductors

NASA Astrophysics Data System (ADS)

Bamba, S.; Tanaka, Y.; Ando, T.; Ueda, H.; Ishiyama, A.; Yamada, Y.; Shiohara, Y.

2008-02-01

In this paper, we report the fatigue characteristics of IBAD/PLD YBCO coated conductors. A YBCO coated conductor used in the superconducting coil of a SMES system is repeatedly subjected to mechanical tensile or compressive strain due to the Lorentz force during electrical charging or discharging. The superconducting characteristic of this conductor may deteriorate because of this cyclic strain. Therefore, it is necessary to investigate the effect of cyclic strain on the superconducting characteristics of YBCO coated conductors that have a laminated structure. We developed an experimental apparatus with a U-shaped sample holder in order to apply cyclic strain to the sample tape. This apparatus was used to perform the fatigue tests on YBCO coated conductors in liquid nitrogen in the absence of an external magnetic field. The strain cycles with the maximum strain epsilonmax (zero external strain → epsilonmax → zero external strain) were applied and repeated up to 5000 times, and the Ic measurements were performed at epsilonmax. Therefore, the application of cyclic strain with epsilonmax ranging from 0.3% to 0.5% did not result in any significant deterioration of the superconducting characteristics of the conductor.

On the use of copper-based substrates for YBCO coated conductors

NASA Astrophysics Data System (ADS)

Vannozzi, A.; Fabbri, F.; Augieri, A.; Angrisani Armenio, A.; Galluzzi, V.; Mancini, A.; Rizzo, F.; Rufoloni, A.; Padilla, J. A.; Xuriguera, E.; De Felicis, D.; Bemporad, E.; Celentano, G.

2014-05-01

It is well known that the recrystallization texture of heavily cold-rolled pure copper is almost completely cubic. However, one of the main drawbacks concerning the use of pure copper cube-textured substrates for YBCO coated conductor is the reduced secondary recrystallization temperature. The onset of secondary recrystallization (i.e., the occurrence of abnormal grains with unpredictable orientation) in pure copper substrate was observed within the typical temperature range required for buffer layer and YBCO processing (600-850 °C). To avoid the formation of abnormal grains the effect of both grain size adjustment (GSA) and recrystallization annealing was analyzed. The combined use of a small initial grain size and a recrystallization two-step annealing (TSA) drastically reduced the presence of abnormal grains in pure copper tapes. Another way to overcome the limitation imposed by the formation of abnormal grains is to deposit a buffer layer at temperatures where secondary recrystallization does not occur. For example, La2Zr2O7 (LZO) film with a high degree of epitaxy was grown by metal-organic decomposition (MOD) at 1000 °C on pure copper substrate. In several samples the substrate underwent secondary recrystallization. Our experiments indicate that the motion of grain boundaries occurring during secondary recrystallization process does not affect the quality of LZO film.

Electrical and magnetic properties of conductive Cu-based coated conductors

NASA Astrophysics Data System (ADS)

Aytug, T.; Paranthaman, M.; Thompson, J. R.; Goyal, A.; Rutter, N.; Zhai, H. Y.; Gapud, A. A.; Ijaduola, A. O.; Christen, D. K.

2003-11-01

The development of YBa2Cu3O7-δ (YBCO)-based coated conductors for electric power applications will require electrical and thermal stabilization of the high-temperature superconducting (HTS) coating. In addition, nonmagnetic tape substrates are an important factor in order to reduce the ferromagnetic hysteresis energy loss in ac applications. We report progress toward a conductive buffer layer architecture on biaxially textured nonmagnetic Cu tapes to electrically couple the HTS layer to the underlying metal substrate. A protective Ni overlayer, followed by a single buffer layer of La0.7Sr0.3MnO3, was employed to avoid Cu diffusion and to improve oxidation resistance of the substrate. Property characterizations of YBCO films on short prototype samples revealed self-field critical current density (Jc) values exceeding 2×106 A/cm2 at 77 K and good electrical connectivity. Magnetic hysteretic loss due to Ni overlayer was also investigated.

Microstructural investigation of current barriers in high temperature superconducting tapes and coated conductors

NASA Astrophysics Data System (ADS)

Reeves, Jodi Lynn

Microstructural barriers to supercurrent occur on many length scales in all high temperature oxide superconductors. Eliminating microstructural barriers is key to making these potentially valuable materials more favorable for commercial applications. In silver-sheathed Bi2Sr2CaCu 2Ox (Bi-2212) tapes and multifilaments, the principal barriers on the scale of 10--100's of micrometers are bubbling, porosity, second phase particles, and poorly aligned grains. In state-of-the-art YBa2 Cu3Ox (YBCO) coated conductors, supercurrent barriers on the 0.1--100mum scale are grain boundaries. This thesis work clarifies the role of grain boundaries in the nickel substrate of RABiTS (Rolling Assisted Biaxially Textured Substrate) coated conductors. Plan-view SEM imaging, focused ion beam cutting, magneto-optical imaging and grain orientation mapping were used to determine barriers to supercurrent. Experiments showed enhanced magnetic flux penetration, and hence reduced Jc, in the YBCO above nearly all nickel grain boundaries with misorientation angles (theta) greater than 5°, independent of the rotation axis. Monochromatic backscattered electron Kikuchi pattern percolation maps imply there is a fully connected current path through the YBCO microstructure within the chosen tolerance angle criterion of the map. However, it is the grain boundary map that displays the constrictions of the current path. Therefore, grain boundary maps are better tools for illustrating supercurrent barriers than percolation maps. Grain boundary maps and grain orientation maps were used to investigate how the texture of the substrate was transferred to the buffer layers and to the superconductor. Most grasp boundaries in the nickel were replicated in the buffer and superconductor layers with the same misorientation angle. Anisotropic growth and/or surface energy minimization may be responsible for the improvement in c-axis alignment in the YBCO over the buffer layer. However, the YBCO mosaic spread did not eliminate high angle grain boundaries, since >5° boundaries were still seen in YBCO grain boundary maps. The results of this study on microstructural current barriers show that Jc improvements in RABiTS-type coated conductors require eliminating theta > 5° boundaries in the nickel substrate.

Magnetic suspension using high temperature superconducting cores

NASA Technical Reports Server (NTRS)

Scurlock, R. G.

1992-01-01

The development of YBCO high temperature superconductors, in wire and tape forms, is rapidly approaching the point where the bulk transport current density j vs magnetic field H characteristics with liquid nitrogen cooling will enable its use in model cores. On the other hand, BSCCO high temperature superconductor in wire form has poor j-H characteristics at 77 K today, although with liquid helium or hydrogen cooling, it appears to be superior to NbTi superconductor. Since liquid nitrogen cooling is approx. 100 times cheaper than liquid helium cooling, the use of YBCO is very attractive for use in magnetic suspension. The design is discussed of a model core to accommodate lift and drag loads up to 6000 and 3000 N respectively. A comparison is made between the design performance of a liquid helium cooled NbTi (or BSCCO) superconducting core and a liquid nitrogen cooled YBCO superconducting core.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Polat, Ozgur; Ertugrul, Memhet; Thompson, James R

To obtain an engineered surface for deposition of high-Tc superconductors, nanoscale modulations of the surface of the underlying LaMnO3 (LMO) cap layer is a potential source for generating microstructural defects in YBa2Cu3O7- (YBCO) films. These defects may improve the flux-pinning and consequently increase the critical current density, Jc. To provide such nanoscale modulation via a practical and scalable process, tantalum (Ta) and palladium (Pd) nano-islands were deposited using dc-magnetron sputtering on the surface of the cap layer of commercial metal tape templates for second-generation wires. The size and density of these nano-islands can be controlled by changing sputtering conditions suchmore » as the power and deposition time. Compared to the reference sample grown on an untreated LMO cap layer, the YBCO films grown on the LMO cap layers with Ta or Pd nano-islands exhibited improved in-field Jc performance. Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) were used to assess the evolving size and density of the nano-islands.« less

Analytical investigation in bending characteristic of twisted stacked-tape cable conductor

NASA Astrophysics Data System (ADS)

Takayasu, Makoto; Chiesa, Luisa

2015-12-01

An analytical model to evaluate bending strains of a twisted stack-tape cable (TSTC) conductor has been developed. Through a comparison with experimental results obtained for a soldered 32-tape YBCO TSTC conductor, it has been found that a Perfect-Slip Model (PSM) taking into account the slipping between tapes in a stacked-tape cable during bending gives much better estimation of the bending performance compared to a No-Slip Model (NSM). In the PSM case the tapes can slip so that the internal longitudinal axial strain can be released. The longitudinal strains of compression and tension regions along the tape are balanced in one twist-pitch and cancel out evenly in a long cable. Therefore, in a cable the strains due to bending can be minimized. This is an important advantage of a TSTC conductor. The effect of the cable diameter size on the bending strain is also expected to be minor, and all tapes composing a TSTC conductor have the same strain response under bending, therefore the cable critical current can be characterized from a single tape behaviour.

Specific Heat and Thermal Diffusivity of YBCO Coated Conductors

NASA Astrophysics Data System (ADS)

Naito, Tomoyuki; Fujishiro, Hiroyuki; YasuhisaYamamura; Saito, Kazuya; Okamoto, Hiroshi; Hayashi, Hidemi; Gosho, Yoshihiro; Ohkuma, Takeshi; Shiohara, Yuh

We have measured the temperature dependence of specific heat,C(T), for Ag deposited YBCO coated conductor (YCC),YCC reinforced by a thin Cutape (YCC-Cu), andthe Hastelloy substrate with buffer layer. C(T) of HastelloyC-276 with buffer layer agrees well with the reported oneof HastelloyC-276, indicating that the contribution of the buffer layer to the measured C(T) is negligibly small. C(T)of both YCC and YCC-Cu tapes was successfully reproduced by the simple sum rule using the C(T) values reported for Hastelloy, Ag and Cu. The results demonstrate that C(T) of various YCC tapes can be estimated using the reported C(T)of constitutional materials. The estimated thermal diffusivity, a = K/C, at 300K of YCC, which was estimated using the thermal conductivity, K, did not agree with the reported a of Ag. This resultwas in consistent with the fact that the applied heat flew through the Aglayer, suggesting that a relation of a = K/Cfor homogeneous material cannot be applicable for the layered material such as YCC.

Pulsed laser deposition of YBCO films on ISD MgO buffered metal tapes

NASA Astrophysics Data System (ADS)

Ma, B.; Li, M.; Koritala, R. E.; Fisher, B. L.; Markowitz, A. R.; Erck, R. A.; Baurceanu, R.; Dorris, S. E.; Miller, D. J.; Balachandran, U.

2003-04-01

Biaxially textured magnesium oxide (MgO) films deposited by inclined-substrate deposition (ISD) are desirable for rapid production of high-quality template layers for YBCO-coated conductors. High-quality YBCO films were grown on ISD MgO buffered metallic substrates by pulsed laser deposition (PLD). Columnar grains with a roof-tile surface structure were observed in the ISD MgO films. X-ray pole figure analysis revealed that the (002) planes of the ISD MgO films are tilted at an angle from the substrate normal. A small full-width at half maximum (FWHM) of approx9° was observed in the phi-scan for ISD MgO films deposited at an inclination angle of 55°. In-plane texture in the ISD MgO films developed in the first approx0.5 mum from the substrate surface, and then stabilized with further increases in film thickness. Yttria-stabilized zirconia and ceria buffer layers were deposited on the ISD MgO grown on metallic substrates prior to the deposition of YBCO by PLD. YBCO films with the c-axis parallel to the substrate normal have a unique orientation relationship with the ISD MgO films. An orientation relationship of YBCOlangle100rangleparallelMgOlangle111rangle and YBCOlangle010rangleparallelMgOlangle110rangle was measured by x-ray pole figure analyses and confirmed by transmission electron microscopy. A Tc of 91 K with a sharp transition and transport Jc of 5.5 × 105 A cm-2 at 77 K in self-field were measured on a YBCO film that was 0.46 mum thick, 4 mm wide and 10 mm long.

Voltage-ampere characteristics of YBCO coated conductor under inhomogeneous oscillating magnetic field

NASA Astrophysics Data System (ADS)

Geng, J.; Shen, B.; Li, C.; Zhang, H.; Matsuda, K.; Li, J.; Zhang, X.; Coombs, T. A.

2016-06-01

Direct current carrying type II superconductors present a dynamic resistance when subjected to an oscillating magnetic field perpendicular to the current direction. If a superconductor is under a homogeneous field with high magnitude, the dynamic resistance value is nearly independent of transport current. Hoffmann and coworkers [Hoffmann et al., IEEE Trans. Appl. Supercond. 21, 1628 (2011)] discovered, however, flux pumping effect when a superconducting tape is under an inhomogeneous field orthogonal to the tape surface generated by rotating magnets. Following their work, we report the whole Voltage-Ampere (V-I) curves of an YBCO coated conductor under permanent magnets rotating with different frequencies and directions. We discovered that the two curves under opposite rotating directions differ from each other constantly when the transport current is less than the critical current, whereas the difference gradually reduces after the transport current exceeds the critical value. We also find that for different field frequencies, the difference between the two curves decreases faster with lower field frequency. The result indicates that the transport loss is dependent on the relative direction of the transport current and field travelling, which is distinct from traditional dynamic resistance model. The work may be instructive for the design of superconducting motors.

Influence of artificial pinning centers on structural and superconducting properties of thick YBCO films on ABAD-YSZ templates

NASA Astrophysics Data System (ADS)

Pahlke, Patrick; Sieger, Max; Ottolinger, Rick; Lao, Mayraluna; Eisterer, Michael; Meledin, Alexander; Van Tendeloo, Gustaaf; Hänisch, Jens; Holzapfel, Bernhard; Schultz, Ludwig; Nielsch, Kornelius; Hühne, Ruben

2018-04-01

Recent efforts in the development of YBa2Cu3O7-x (YBCO) coated conductors are devoted to the increase of the critical current I c in magnetic fields. This is typically realized by growing thicker YBCO layers as well as by the incorporation of artificial pinning centers. We studied the growth of doped YBCO layers with a thickness of up to 7 μm using pulsed laser deposition with a growth rate of about 1.2 nm s-1. Industrially fabricated ion-beam textured YSZ templates based on metal tapes were used as substrates for this study. The incorporation of BaHfO3 (BHO) or Ba2Y(Nb0.5Ta0.5)O6 (BYNTO) secondary phase additions leads to a denser microstructure compared to undoped films. A purely c-axis-oriented YBCO growth is preserved up to a thickness of about 4 μm, whereas misoriented texture components were observed in thicker films. The critical temperature is slightly reduced compared to undoped films and independent of film thickness. The critical current density J c of the BHO- and BYNTO-doped YBCO layers is lower at 77 K and self-field compared to pure YBCO layers; however, I c increases up to a thickness of 5 μm. A comparison between films with a thickness of 1.3 μm revealed that the anisotropy of the critical current density J c(θ) strongly depends on the incorporated pinning centers. Whereas BHO nanorods lead to a strong B∣∣c-axis peak, the overall anisotropy is significantly reduced by the incorporation of BYNTO forming a mixture of short c-axis-oriented nanorods and small (a-b)-oriented platelets. As a result, the J c values of the doped films outperform the undoped samples at higher fields and lower temperatures for most magnetic field directions.

Double disordered YBCO coated conductors of industrial scale: high currents in high magnetic field

NASA Astrophysics Data System (ADS)

Abraimov, D.; Ballarino, A.; Barth, C.; Bottura, L.; Dietrich, R.; Francis, A.; Jaroszynski, J.; Majkic, G. S.; McCallister, J.; Polyanskii, A.; Rossi, L.; Rutt, A.; Santos, M.; Schlenga, K.; Selvamanickam, V.; Senatore, C.; Usoskin, A.; Viouchkov, Y. L.

2015-11-01

A significant increase of critical current in high magnetic field, up to 31 T, was recorded in long tapes manufactured by employing a double-disorder route. In a double-disordered high-temperature superconductor (HTS), a superimposing of intrinsic and extrinsic disorder takes place in a way that (i) the intrinsic disorder is caused by local stoichiometry deviations that lead to defects of crystallinity that serve as pining centers in the YBa2Cu3O x-δ matrix and (ii) the extrinsic disorder is introduced via embedded atoms or particles of foreign material (e.g. barium zirconate), which create a set of lattice defects. We analyzed possible technological reasons for this current gain. The properties of these tapes over a wider field-temperature range as well as field anisotropy were also studied. Record values of critical current as high as 309 A at 31 T, 500 A at 18 Tm and 1200 A at 5 T were found in 4 mm wide tape at 4.2 K and B perpendicular to tape surface. HTS layers were processed in medium-scale equipment that allows a maximum batch length of 250 m while 22 m long batches were provided for investigation. Abnormally high ratios (up to 10) of critical current density measured at 4.2 K, 19 T to critical current density measured at 77 K, self-field were observed in tapes with the highest in-field critical current. Anisotropy of the critical current as well as angular dependences of n and α values were investigated. The temperature dependence of critical current is presented for temperatures between 4.2 and 40 K. Prospects for the suppression of the dog-bone effect by Cu plating and upscale of processing chain to >500 m piece length are discussed.

Investigation of thick PLD-GdBCO and ZrO2 doped GdBCO coated conductors with high critical current on PLD-CeO2 capped IBAD-GZO substrate tapes

NASA Astrophysics Data System (ADS)

Takahashi, K.; Kobayashi, H.; Yamada, Y.; Ibi, A.; Fukushima, H.; Konishi, M.; Miyata, S.; Shiohara, Y.; Kato, T.; Hirayama, T.

2006-09-01

In order to increase the critical current, Ic, we have fabricated thick GdBa2Cu3O7-δ (GdBCO) coated conductors (CCs) by the pulsed laser deposition (PLD) method on PLD-CeO2/ion-beam assisted deposition (IBAD)-Gd2Zr2O7 (GZO)/hastelloy metal substrate tapes. The highest critical current value was 522 A cm-1 for a thickness of 3.6 µm in self-field at 77 K. It was found that a low volume fraction of a-axis orientated grains was obtained in the thick GdBCO CCs, compared to YBa2Cu3O7-δ (YBCO) CCs. Consequently, the GdBCO CCs showed higher critical current density (Jc) than YBCO CCs in all thicknesses from 0.2 to 3.6 µm. Furthermore, we have succeeded in improving Ic in a magnetic field by the introduction of artificial pinning centres using a 5 mol% ZrO2 doped GdBCO target. In the measurement of the Ic dependence on the magnetic field angle, θ, Ic was much improved, especially at 0°, i.e., with the magnetic field parallel to the c-axis. The Ic value at 3 T was 59.5 A cm-1 at 0° and it showed a minimum of 42.3 A cm-1 at 82° for 2.28 µm thick CC. The minimum value in the angular dependence of Ic at 3 T was about five times higher than that of YBCO CC and two times higher than that of pure GdBCO CC.

Apparatus and method for measuring critical current properties of a coated conductor

DOEpatents

Mueller, Fred M [Los Alamos, NM; Haenisch, Jens [Dresden, DE

2012-07-24

The transverse critical-current uniformity in a superconducting tape was determined using a magnetic knife apparatus. A critical current I.sub.c distribution and transverse critical current density J.sub.c distribution in YBCO coated conductors was measured nondestructively with high resolution using a magnetic knife apparatus. The method utilizes the strong depression of J.sub.c in applied magnetic fields. A narrow region of low, including zero, magnetic field in a surrounding higher field is moved transversely across a sample of coated conductor. This reveals the critical current density distribution. A Fourier series inversion process was used to determine the transverse J.sub.c distribution in the sample.

Passivation of Flexible YBCO Superconducting Current Lead With Amorphous SiO2 Layer

NASA Technical Reports Server (NTRS)

Johannes, Daniel; Webber, Robert

2013-01-01

Adiabatic demagnetization refrigerators (ADR) are operated in space to cool detectors of cosmic radiation to a few 10s of mK. A key element of the ADR is a superconducting magnet operating at about 0.3 K that is continually energized and de-energized in synchronism with a thermal switch, such that a piece of paramagnetic salt is alternately warm in a high magnetic field and cold in zero magnetic field. This causes the salt pill or refrigerant to cool, and it is able to suck heat from an object, e.g., the sensor, to be cooled. Current has to be fed into and out of the magnets from a dissipative power supply at the ambient temperature of the spacecraft. The current leads that link the magnets to the power supply inevitably conduct a significant amount of heat into the colder regions of the supporting cryostat, resulting in the need for larger, heavier, and more powerful supporting refrigerators. The aim of this project was to design and construct high-temperature superconductor (HTS) leads from YBCO (yttrium barium copper oxide) composite conductors to reduce the heat load significantly in the temperature regime below the critical temperature of YBCO. The magnet lead does not have to support current in the event that the YBCO ceases to be superconducting. Cus - tomarily, a normal metal conductor in parallel with the YBCO is a necessary part of the lead structure to allow for this upset condition; however, for this application, the normal metal can be dispensed with. Amorphous silicon dioxide is deposited directly onto the surface of YBCO, which resides on a flexible substrate. The silicon dioxide protects the YBCO from chemically reacting with atmospheric water and carbon dioxide, thus preserving the superconducting properties of the YBCO. The customary protective coating for flexible YBCO conductors is silver or a silver/gold alloy, which conducts heat many orders of magnitude better than SiO2 and so limits the use of such a composite conductor for passing current across a thermal gradient with as little flow of heat as possible to make an efficient current lead. By protecting YBCO on a flexible substrate of low thermal conductivity with SiO2, a thermally efficient and flexible current lead can be fabricated. The technology is also applicable to current leads for 4 K superconducting electronics current biasing. A commercially available thin-film YBCO composite tape conductor is first stripped of its protective silver coating. It is then mounted on a jig that holds the sample flat and acts as a heat sink. Silicon dioxide is then deposited onto the YBCO to a thickness of about 1 micron using PECVD (plasma-enhanced chemical vapor deposition), without heating the YBCO to the point where degradation occurs. Since SiO2 can have good high-frequency electrical properties, it can be used to coat YBCO cable structures used to feed RF signals across temperature gradients. The prime embodiment concerns the conduction of DC current across the cryogenic temperature gradient. The coating is hard and electrically insulating, but flexible.

High Temperature Superconductor Josephson Weak Links

NASA Technical Reports Server (NTRS)

Hunt, B. D.; Barner, J. B.; Foote, M. C.; Vasquez, R. C.

1993-01-01

High T_c edge-geometry SNS microbridges have been fabricated using ion-damaged YBa_2Cu_3O_(7-x) (YBCO) and a nonsuperconducting phase of YBCO (N-YBCO) as normal metals. Optimization of the ion milling process used for YBCO edge formation and cleaning has resulted in ion-damage barrier devices which exhibit I-V characteristics consistent with the Resistively-Shunted-Junction (RSJ) model, with typical current densities (J_c) of approximately 5 x 10^6 A/cm^2 at 4.2 K. Characterization of N-YBCO films suggests that N-YBCO is the orthorhombic YBCO phase with oxygen disorder suppressing T_c...

Buffer layers on metal alloy substrates for superconducting tapes

DOEpatents

Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

2004-06-29

An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected IC's of over 200 Amperes across a sample 1 cm wide.

Buffer layers on metal alloy substrates for superconducting tapes

DOEpatents

Jia, Quanxi; Foltyn, Stephen R.; Arendt, Paul N.; Groves, James R.

2004-10-05

An article including a substrate, at least one intermediate layer upon the surface of the substrate, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the at least one intermediate layer, and a layer of a SrRuO.sub.3 buffer material upon the oriented cubic oxide material layer is provided together with additional layers such as a HTS top-layer of YBCO directly upon the layer of a SrRuO.sub.3 buffer material layer. With a HTS top-layer of YBCO upon at least one layer of the SrRuO.sub.3 buffer material in such an article, J.sub.c 's of up to 1.3.times.10.sup.6 A/cm.sup.2 have been demonstrated with projected I.sub.c 's of over 200 Amperes across a sample 1 cm wide.

Indigenously developed bending strain setup for I-V characterization of superconducting tapes and wires

NASA Astrophysics Data System (ADS)

Panchal, Arun; Bano, Anees; Ghate, Mahesh; Raj, Piyush; Pradhan, Subrata

2017-04-01

An indigenously developed bending strain setup to examine the effect of pure bending on critical current of superconducting tapes and strands has been presented in this paper. This set up is capable of applying various bending radius in situ at cryogenic temperature with rack and pinion gear mechanism. The bending strain applied on samples can be controlled externally by rotational input which is transferred in the form of bending radius during experiments. The working principle, design and optimization of this set up have been discussed. The performance and validation of this setup has been done on various HTS tapes and copper strands at 77 K in actual experimental facility. Effect of bending radius (15.5 mm - 48 mm) i.e. strains and ramp rate (2 A/s - 8 A/s) is observed on current capability of various HTS Tapes. It is observed that in uniform bending condition, degradation in current carrying capacity BSCCO and Di-BSCCO (˜ 30 %) is more as compare to YBCO (˜ 2.75 %) at 77 K. The effect of pure mechanical strain has been experimentally observed and presented.

Current status and future prospects of Japanese national project on coated conductor development and its applications

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-09-01

Four years of the current five-year national project since 2003 for development of coated conductors using Y-system superconductors have passed and lots of remarkable results have been achieved. In this paper, the current status and the future prospect of this project are reviewed. The current national project comprises several groups of national laboratories, universities and private companies. The group of high performance tape development, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting tapes on the PLD-CeO 2/IBAD-GZO buffered substrates. The high product of Ic and L equal to 112,166 A m was achieved in the 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm-w. The performance under the magnetic fields was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO 2. About 61 m long GdBCO tape with ZrO 2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, the other group focusing on the low production cost has worked on processes of TFA-MOD and MOCVD, etc. The extremely high Ic value of 735 A/cm-w was attained in the TFA-MOD films on PLD-CeO 2/IBAD-GZO/Hastelloy C276 substrate by means of using the effect of Ba-poor nominal composition. In the efforts for long tape production, 200 m long tapes with high Ic values of 200 A/cm-w and 205 A/cm-w were obtained by MOD-YBCO/PLD-CeO 2/IBAD-GZO/Hastelloy C276 and PLD-HoBCO on buffered NiW substrate, respectively. The Ic × L value of the MOD-derived tape was 40,000 A m, which is the highest value in the world by the MOD process. Based on the above achievements on the coated conductor process development, two new additional goals were set in the project. One is the development for the extremely low cost tape and another is the development of the basic technologies for making the electric power devices including cables, transformers, motors, current-limiters and cryocoolers. Some of the new themes already revealed the marvellous results such as 15 kW motor, low AC loss coils, low AC loss cables, etc.

Highly alloyed Ni-W substrates for low AC loss applications

NASA Astrophysics Data System (ADS)

Gaitzsch, Uwe; Hänisch, Jens; Hühne, Ruben; Rodig, Christian; Freudenberger, Jens; Holzapfel, Bernhard; Schultz, Ludwig

2013-08-01

Cube texture formation has been studied in Ni-W alloys with a W content of 9 at.% and above. These alloys show a low magnetization at 77 K and below, and are therefore excellent candidates for use as substrates of coated conductors in AC applications. The application of a modified deformation and annealing sequence leads to a highly textured surface of Ni9W and Ni9.5W tapes with cube texture fractions above 96%. YBCO (YBa2Cu3O7-δ) layers obtained on these substrates using a standard buffer architecture showed a critical current density exceeding 1.5 MA cm-2 at 77 K, similar to those for films on commercial Ni5W tapes. In contrast, only a weak cube texture was achieved in Ni10W tapes. The rolling texture of this alloy showed a significantly increased Goss component, which could not be reduced by applying intermediate annealing treatments. The influence of this texture on the cube texture formation will be discussed in detail.

Thickness effect of Gd2Zr2O7 buffer layer on performance of YBa2Cu3O7-δ coated conductors

NASA Astrophysics Data System (ADS)

Qiu, Wenbin; Fan, Feng; Lu, Yuming; Liu, Zhiyong; Bai, Chuanyi; Guo, Yanqun; Cai, Chuanbing

2014-12-01

Bilayer buffer architecture of Gd2Zr2O7 (GZO)/Y2O3 was prepared on the biaxially textured tape of Ni-5 at% W (NiW) by reactive sputtering deposition technique. The buffer layer of GZO films were deposited with different thicknesses on Y2O3 seeding layer with a given thickness of 20 nm. According to the results of φ-scan, the in-plane FWHMs of GZO films decreased and then reversed with increasing thickness of GZO, which corresponded with the in-plane FWHMs and superconducting properties of YBa2Cu3O7-δ (YBCO) films. Reflection High-Energy Electron Diffraction (RHEED) was carried out to examine the surface texture of GZO films and the deteriorated surface alignment was found for thicker films. The thickness effect of GZO on performance of YBCO is the coupling result of surface texture and blocking effect caused by thickness. With the balance of these two factors, the YBCO/GZO(120 nm)/Y2O3/NiW architecture exhibit relatively high performance with the transition temperature Tc of 92 K, a transition width ΔTc below 1 K, and a critical current density Jc of 0.65 MA/cm2.

Alternating current loss characteristics in (bismuth,lead)SCCO and yttrium barium copper oxide superconducting tapes

NASA Astrophysics Data System (ADS)

Nguyen, Doan Ngoc

Alternating current (AC) loss and current carrying capacity are two of the most crucial considerations in large-scale power applications of high temperature superconducting (HTS) conductors. AC losses result in an increased thermal load for cooling machines, and thus increased operating costs. Furthermore, AC losses can stimulate quenching phenomena or at least decrease the stability margin for superconducting devices. Thus, understanding AC losses is essential for the development of HTS AC applications. The main focus of this dissertation is to make reliable total AC loss measurements and interpret the experimental results in a theoretical framework. With a specially designed magnet, advanced total AC loss measurement system in liquid nitrogen (77 K) has been successfully built. Both calorimetric and electromagnetic methods were employed to confirm the validity of the measured results and to have a more thorough understanding of AC loss in HTS conductors. The measurement is capable of measuring total AC loss in HTS tapes over a wide range of frequency and amplitude of transport current and magnetic field. An accurate phase control technique allows measurement of total AC loss with any phase difference between the transport current and magnetic field by calorimetric method. In addition, a novel total AC loss measurement system with variable temperatures from 30 K to 100 K was successfully built and tested. Understanding the dependence of AC losses on temperature will enable optimization of the operating temperature and design of HTS devices. As a part of the dissertation, numerical calculations using Brandt's model were developed to study electrodynamics and total AC loss in HTS conductors. In the calculations, the superconducting electrical behavior is assumed to follow a power-law model. In general, the practical properties of conductors, including field-dependence of critical current density Jc, n-value and non-uniform distribution of Jc, can be accounted for in the numerical calculations. The numerical calculations are also capable of investigating eddy current loss in the stabilizer and ferromagnetic loss in the substrate of YBa2Cu3O 7-delta (YBCO) coated conductor. AC loss characteristics and electrodynamics in several (Bi,Pb)2 Sr2Ca2Cu3Ox (Bi-2223) and YBCO tapes were studied experimentally and numerically. It was found that AC loss behavior Ax in HTS tapes is strongly affected by the sample parameters such as cross-section, structure, dimensions, critical current distribution as well as by operation parameters including temperature, frequency, the phase difference between transport current and magnetic field, the orientation of magnetic field. The Ni-5%W substrate in YBCO conductors generates some ferromagnetic loss but this loss component is significantly reduced by a small parallel DC magnetic field. At a given AC magnetic field B0, there is a temperature Tmax at which the magnetization loss is maximum. The design of HTS devices needs to be optimized to avoid operating at that temperature. In general, the total AC loss in HTS tapes is still high for many power device applications, especially for those that present a rather high AC applied magnetic field. The development of low loss conductors is therefore crucial for HTS large-scale applications.

The effect of fast neutron irradiation on the superconducting properties of REBCO coated conductors with and without artificial pinning centers

NASA Astrophysics Data System (ADS)

Fischer, D. X.; Prokopec, R.; Emhofer, J.; Eisterer, M.

2018-04-01

Superconductors are essential components of future fusion power plants. The magnet coils responsible for producing the field required for confining the fusion plasma are exposed to considerable neutron radiation. This makes irradiation studies necessary for understanding the radiation response of the superconductor. High temperature superconductors are promising candidates as magnet coil materials. YBCO and GdBCO tapes of several manufacturers were irradiated to fast neutron fluences of up to 3.9 × 1022 m-2 in the research reactor at the Atominstitut. Low energy neutrons contribute to the fission reactor spectrum but not to the expected spectrum at the fusion magnets. Low energy neutrons have to be shielded in irradiation experiments to avoid their substantial effect on the superconducting properties of tapes containing gadolinium. The critical current (I c) of the tapes in this study was examined at fields of up to 15 T and down to a temperature of 30 K. I c first increases upon irradiation and reaches a maximum at a certain fluence, which depends highly on temperature, being highest at low temperature. I c declines at high fluences and eventually degrades with respect to its initial value. Tapes with artificial pinning centers (APCs) degrade at lower fluences than tapes without them. The n-values decrease in all types of tapes after irradiation even when the critical currents are increased. The field dependence of the volume pinning force differs in pristine tapes with and without APCs but shows the same behavior after irradiation.

Crystal growth of YBCO coated conductors by TFA MOD method

NASA Astrophysics Data System (ADS)

Yoshizumi, M.; Nakanishi, T.; Matsuda, J.; Nakaoka, K.; Sutoh, Y.; Izumi, T.; Shiohara, Y.

2008-09-01

The crystal growth mechanism of TFA (trifluoroacetates)-MOD (metal organic deposition) derived YBa 2Cu 3O y has been investigated to understand the process for higher production rates of the conversion process. YBCO films were prepared by TFA-MOD on CeO 2/Gd 2Zr 2O 7/Hastelloy C276 substrates. The growth rates of YBCO derived from Y:Ba:Cu = 1:2:3 and 1:1.5:3 starting solutions were investigated by XRD and TEM analyses. YBCO growth proceeds in two steps of the epitaxial one from the substrate and solid state reaction. The overall growth rate estimated from the residual amounts of BaF 2 with time measured by XRD is proportional to a square root of P(H 2O). The trend was independent of the composition of starting solutions, however, the growth rate obtained from the 1:1.5:3 starting solutions was high as twice as that of 1:2:3, which could not be explained by the composition of BaF 2 included in the precursor films. On the other hand, the growth rate measured from the thickness of the YBCO quenched film at the same process time showed no difference between the samples of 1:2:3 and 1:1.5:3. The epitaxial growth rate of 1:1.5:3 was also the same as the overall growth rate of that, which means there was no solid state reaction to form YBCO after the epitaxial growth. The YBCO growth mechanism was found to be as follows; YBCO crystals nucleate at the surface of the substrate and epitaxially grow into the precursor by layer-by-layer by a manner with trapping unreacted particles. The amounts of YBCO and the unreacted particles trapped in the YBCO film are independent of the composition of the starting solution in this step. Unreacted particles react with each other to form YBCO and pores by solid state reaction as long as there is BaF 2 left in the film. The Ba-poor starting solution gives little BaF 2 left in the film and so the solid state reaction is completed within a short time, resulting in the fast overall growth rate.

Processing of Superconductor-Normal-Superconductor Josephson Edge Junctions

NASA Technical Reports Server (NTRS)

Kleinsasser, A. W.; Barner, J. B.

1997-01-01

The electrical behavior of epitaxial superconductor-normal-superconductor (SNS) Josephson edge junctions is strongly affected by processing conditions. Ex-situ processes, utilizing photoresist and polyimide/photoresist mask layers, are employed for ion milling edges for junctions with Yttrium-Barium-Copper-Oxide (YBCO) electrodes and primarily Co-doped YBCO interlayers.

The successful incorporation of Ag into single grain, Y-Ba-Cu-O bulk superconductors

NASA Astrophysics Data System (ADS)

Congreve, Jasmin V. J.; Shi, Yunhua; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

2018-07-01

The use of RE-Ba-Cu-O [(RE)BCO] bulk superconductors, where RE = Y, Gd, Sm, in practical applications is, at least in part, limited by their mechanical properties and brittle nature, in particular. Alloying these materials with silver, however, produces a significant improvement in strength without any detrimental impact on their superconducting properties. Unfortunately, the top seeded melt growth technique, used routinely to process bulk (RE)BCO superconductors in the form of large, single grains required for practical applications, is complex and has a large number of inter-related variables, so the addition of silver increases the complexity of the growth process even further. This can make successful growth of this system extremely challenging. Here we report measurements of the growth rate of YBCO-Ag fabricated using a new growth technique consisting of continuous cooling and isothermal hold process. The resulting data form the basis of a model that has been used to derive suitable heating profiles for the successful single grain growth of YBCO-Ag bulk superconductors of up to 26 mm in diameter. The microstructure and distribution of silver within these samples have been studied in detail. The maximum trapped field at the top surface of the bulk YBCO-Ag samples has been found to be comparable to that of standard YBCO processed without Ag. The YBCO-Ag samples also exhibit a much more uniform trapped field profile compared to that of YBCO.

Contact resistance and normal zone formation in coated yttrium barium copper oxide superconductors

NASA Astrophysics Data System (ADS)

Duckworth, Robert Calvin

2001-11-01

This project presents a systematic study of contact resistance and normal zone formation in silver coated YBa2CU3Ox (YBCO) superconductors. A unique opportunity exists in YBCO superconductors because of the ability to use oxygen annealing to influence the interfacial properties and the planar geometry of this type of superconductor to characterize the contact resistance between the silver and YBCO. The interface represents a region that current must cross when normal zones form in the superconductor and a high contact resistance could impede the current transfer or produce excess Joule heating that would result in premature quench or damage of the sample. While it has been shown in single-crystalline YBCO processing methods that the contact resistance of the silver/YBCO interface can be influenced by post-process oxygen annealing, this has not previously been confirmed for high-density films, nor for samples with complete layers of silver deposited on top of the YBCO. Both the influence of contact resistance and the knowledge of normal zone formation on conductor sized samples is essential for their successful implementation into superconducting applications such as transmission lines and magnets. While normal zone formation and propagation have been studied in other high temperature superconductors, the amount of information with respect to YBCO has been very limited. This study establishes that the processing method for the YBCO does not affect the contact resistance and mirrors the dependence of contact resistance on oxygen annealing temperature observed in earlier work. It has also been experimentally confirmed that the current transfer length provides an effective representation of the contact resistance when compared to more direct measurements using the traditional four-wire method. Finally for samples with low contact resistance, a combination of experiments and modeling demonstrate an accurate understanding of the key role of silver thickness and substrate thickness on the stability of silver-coated YBCO Rolling Assisted Bi-Axially Textured Substrates conductors. Both the experimental measurements and the one-dimensional model show that increasing the silver thickness results in an increased thermal runaway current; that is, the current above which normal zones continue to grow due to insufficient local cooling.

Polycrystalline Superconducting Thin Films: Texture Control and Critical Current Density

NASA Astrophysics Data System (ADS)

Yang, Feng

1995-01-01

The growth processes of polycrystalline rm YBa_2CU_3O_{7-X} (YBCO) and yttria-stabilized-zirconia (YSZ) thin films have been developed. The effectiveness of YSZ buffer layers on suppression of the reaction between YBCO thin films and metallic substrates was carefully studied. Grown on the chemically inert surfaces of YSZ buffer layers, YBCO thin films possessed good quality of c-axis alignment with the c axis parallel to the substrate normal, but without any preferred in-plane orientations. This leads to the existence of a large percentage of the high-angle grain boundaries in the YBCO films. The critical current densities (rm J_{c}'s) found in these films were much lower than those in single crystal YBCO thin films, which was the consequence of the weak -link effect of the high-angle grain boundaries in these films. It became clear that the in-plane alignment is vital for achieving high rm J_{c }s in polycrystalline YBCO thin films. To induce the in-plane alignment, ion beam-assisted deposition (IBAD) technique was integrated into the conventional pulsed laser deposition process for the growth of the YSZ buffer layers. It was demonstrated that using IBAD the in-plane orientations of the YSZ grains could be controlled within a certain range of a common direction. This ion -bombardment induced in-plane texturing was explained using the anisotropic sputtering yield theory. Our observations and analyses have provided valuable information on the optimization of the IBAD process, and shed light on the texturing mechanism in YSZ. With the in-plane aligned YSZ buffer layers, YBCO thin films grown on metallic substrates showed improved rm J_{c}s. It was found that the in-plane alignment of YSZ and that of YBCO were closely related. A direct correlation was revealed between the rm J_{c} value and the degree of the in-plane alignment for the YBCO thin films. To explain this correlation, a numerical model was applied to multi-grain superconducting paths with different textures to determine the expected rm J_{c}s. The good agreement between the experimental data and numerical results confirmed that the rm J_{c} improvement directly resulted from the reduction of the number of high-angle grain boundaries in the in-plane aligned polycrystalline YBCO thin films, and provided a guideline on the further improvement of the rm J_ {c}s of polycrystalline YBCO thin films.

Exfoliated YBCO filaments for second-generation superconducting cable

NASA Astrophysics Data System (ADS)

Solovyov, Vyacheslav; Farrell, Paul

2017-01-01

The second-generation high temperature superconductor (2G HTS) wire is the most promising conductor for high-field magnets such as accelerator dipoles and compact fusion devices. The key element of the wire is a thin Y1Ba2Cu3O7 (YBCO) layer deposited on a flexible metal substrate. The substrate, which becomes incorporated in the 2G conductor, reduces the electrical and mechanical performance of the wire. This is a process that exfoliates the YBCO layer from the substrate while retaining the critical current density of the superconductor. Ten-centimeter long coupons of exfoliated YBCO layers were manufactured, and detailed structural, electrical, and mechanical characterization were reported. After exfoliation, the YBCO layer was supported by a 75 μm thick stainless steel foil, which makes for a compact, mechanically stronger, and inexpensive conductor. The critical current density of the filaments was measured at both 77 K and 4.2 K. The exfoliated YBCO retained 90% of the original critical current. Similarly, tests in an external magnetic field at 4.2 K confirmed that the pinning strength of the YBCO layer was also retained following exfoliation.

Solderability study of RABiTS-based YBCO coated conductors

NASA Astrophysics Data System (ADS)

Zhang, Yifei; Duckworth, Robert C.; Ha, Tam T.; Gouge, Michael J.

2011-08-01

The solderability of commercially available YBa2Cu3O7-x (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and with two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.

Solderability Study of RABiTS-Based YBCO Coated Conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yifei; Duckworth, Robert C; Ha, Tam T

2011-01-01

The solderability of commercially available YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) coated conductors that were made from Rolling Assisted Biaxially Textured Substrates (RABiTS)-based templates was studied. The coated conductors, also known as second-generation (2G) high temperature superconductor (HTS) wires (in the geometry of flat tapes about 4 mm wide), were laminated with copper, brass, or stainless steel strips as stabilizers. To understand the factors that influence their solderability, surface profilometry and scanning electron microscopy were used to characterize the wire surfaces. The solderability of three solders, 52In48Sn, 67Bi33In, and 100In (wt.%), was evaluated using a standard test (IPC/ECA J-STD-002) and withmore » two different commercial fluxes. It was found that the solderability varied with the solder and flux but the three different wires showed similar solderability for a fixed combination of solder and flux. Solder joints of the 2G wires were fabricated using the tools and the procedures recommended by the HTS wire manufacturer. The solder joints were made in a lap-joint geometry and with the superconducting sides of the two wires face-to-face. The electrical resistances of the solder joints were measured at 77 K, and the results were analyzed to qualify the soldering materials and evaluate the soldering process. It was concluded that although the selection of soldering materials affected the resistance of a solder joint, the resistivity of the stabilizer was the dominant factor.« less

Superconductivity devices: Commercial use of space

NASA Technical Reports Server (NTRS)

Haertling, Gene; Furman, Eugene; Hsi, Chi-Shiung; Li, Guang

1993-01-01

A YBCO thick film containing 20 percent Ag2O with a T(sub c) of 86.8 K and J(sub c) of 108 A/sq cm was obtained. The film was fabricated by a two-step firing process, i.e., firing the film at 1000 C for 10 minutes and annealing at 970 C for 30 minutes. The two-step firing process, however, was not suitable for the multiple-lead YBCO sample due to the formation of the 211 green phase at 1000 C in the multiple-lead YBCO sample. A BSCCO thick film printed on a MgO coated MSZ substrate and fired at 845 C for 2 hours exhibited a superconducting behavior at 89 K. Because of its porous microstructure, the critical current density of the BSCCO thick film was limited. This report also includes the results of the YBCO and BSCCO materials used as oxide electrodes for ferroelectric materials. The YBCO electroded PLZT showed higher remanent polarization and coercive field than the sample electroded with silver paste. A higher Curie temperature for the PLZT was obtained from the YBCO electroded sample. The BSCCO electroded sample, however, exhibited the same Curie temperature as that of a silver electroded sample. Dissipation factors of the ferroelectric samples increased when the oxide electrode was applied.

Self-doping processes between planes and chains in the metal-to-superconductor transition of YBa2Cu3O6.9.

PubMed

Magnuson, M; Schmitt, T; Strocov, V N; Schlappa, J; Kalabukhov, A S; Duda, L-C

2014-11-12

The interplay between the quasi 1-dimensional CuO-chains and the 2-dimensional CuO2 planes of YBa(2)Cu(3)O(6+x) (YBCO) has been in focus for a long time. Although the CuO-chains are known to be important as charge reservoirs that enable superconductivity for a range of oxygen doping levels in YBCO, the understanding of the dynamics of its temperature-driven metal-superconductor transition (MST) remains a challenge. We present a combined study using x-ray absorption spectroscopy and resonant inelastic x-ray scattering (RIXS) revealing how a reconstruction of the apical O(4)-derived interplanar orbitals during the MST of optimally doped YBCO leads to substantial hole-transfer from the chains into the planes, i.e. self-doping. Our ionic model calculations show that localized divalent charge-transfer configurations are expected to be abundant in the chains of YBCO. While these indeed appear in the RIXS spectra from YBCO in the normal, metallic, state, they are largely suppressed in the superconducting state and, instead, signatures of Cu trivalent charge-transfer configurations in the planes become enhanced. In the quest for understanding the fundamental mechanism for high-Tc-superconductivity (HTSC) in perovskite cuprate materials, the observation of such an interplanar self-doping process in YBCO opens a unique novel channel for studying the dynamics of HTSC.

Thermally actuated magnetization flux pump in single-grain YBCO bulk

NASA Astrophysics Data System (ADS)

Yan, Yu; Li, Quan; Coombs, T. A.

2009-10-01

Recent progress in material processing has proved that high temperature superconductors (HTS) have a great potential to trap large magnetic fields at cryogenic temperatures. For example, HTS are widely used in MRI scanners and in magnetic bearings. However, using traditional ways to magnetize, the YBCO will always need the applied field to be as high as the expected field on the superconductor or much higher than it, leading to a much higher cost than that of using permanent magnets. In this paper, we find a method of YBCO magnetization in liquid nitrogen that only requires the applied field to be at the level of a permanent magnet. Moreover, rather than applying a pulsed high current field on the YBCO, we use a thermally actuated material (gadolinium) as an intermedia and create a travelling magnetic field through it by changing the partial temperature so that the partial permeability is changed to build up the magnetization of the YBCO gradually after multiple pumps. The gadolinium bulk is located between the YBCO and the permanent magnet and is heated and cooled repeatedly from the outer surface to generate a travelling thermal wave inwards. In the subsequent experiment, an obvious accumulation of the flux density is detected on the surface of the YBCO bulk.

Frequency dependence of magnetic ac loss in a Roebel cable made of YBCO on a Ni-W substrate

NASA Astrophysics Data System (ADS)

Lakshmi, L. S.; Staines, M. P.; Badcock, R. A.; Long, N. J.; Majoros, M.; Collings, E. W.; Sumption, M. D.

2010-08-01

We have investigated the frequency dependent contributions to the magnetic ac loss in a 10 strand Roebel cable with 2 mm wide non-insulated strands and a transposition length of 90 mm. This cable is made from 40 mm wide YBCO coated conductor tape manufactured by AMSC and stabilized by electroplating 25 µm thick copper on either side prior to the mechanical punching of the cable strands. The measurements were carried out in both perpendicular and parallel field orientation, at frequencies in the range of 30-200 Hz. While the loss in the perpendicular orientation is predominantly hysteretic in nature, we observe some frequency dependence of the loss when the cable approaches full flux penetration at high field amplitudes. The magnitude is consistent with eddy current losses in the copper stabilization layer. This supports the fact that the inter-strand coupling loss is not significant in this frequency range. In the parallel field orientation, the hysteresis loss in the Ni-W alloy substrate dominates, but we see an unusually strong frequency dependent contribution to the loss which we attribute to intra-strand current loops.

Effect of template post-annealing on Y(Dy)BaCuO nucleation on CeO2 buffered metallic tapes

NASA Astrophysics Data System (ADS)

Hu, Xuefeng; Zhong, Yun; Zhong, Huaxiao; Fan, Feng; Sang, Lina; Li, Mengyao; Fang, Qiang; Zheng, Jiahui; Song, Haoyu; Lu, Yuming; Liu, Zhiyong; Bai, Chuanyi; Guo, Yanqun; Cai, Chuanbing

2017-08-01

Substrate engineering is very significant in the synthesis of the high-temperature superconductor (HTS) coated conductor. Here we design and synthesize several distinct and stable Cerium oxide (CeO2) surface reconstructions which are used to grow epitaxial films of the HTS YBa2Cu3O7-δ (YBCO). To identify the influence of annealing and post-annealing surroundings on the nature of nucleation centers, including Ar/5%H2, humid Ar/5%H2 and O2 in high temperature annealing process, we study the well-controlled structure, surface morphology, crystal constants and surface redox processes of the ceria buffers by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and field-emission scanning electronic microscopy (FE-SEM), respectively. The ceria film post-annealed under humid Ar/5%H2 gas shows the best buffer layer properties. Furthermore, the film absorbs more oxygen ions, which appears to contribute to oxygenation of superconductor film. The film is well-suited for ceria model studies as well as a perfect substitute for CeO2 bulk material.

Enhanced pinning in YBCO films with BaZrO.sub.3 nanoparticles

DOEpatents

Driscoll, Judith L.; Foltyn, Stephen R.

2010-06-15

A process and composition of matter are provided and involve flux pinning in thin films of high temperature superconductive oxides such as YBCO by inclusion of particles including barium and a group 4 or group 5 metal, such as zirconium, in the thin film.

Influence of ZnO doping on the properties of single domain YBCO bulks fabricated by RE+011 TSIG process

NASA Astrophysics Data System (ADS)

Yang, W. M.; Yuan, X. C.; Guo, Y. X.

2017-10-01

Single domain YBCO bulk superconductors with different additions of ZnO have been successfully fabricated by RE+011 TSIG process with a new solid phase of [(100-x)(Y2O3 + 1.2BaCuO2)+xZnO] and a new liquid phase of (Y2O3+6CuO+10BaCuO2). The effects of ZnO additions on the growth morphology, microstructure, critical temperature (Tc), the levitation force and trapped field of the YBCO bulks have been investigated. It is found that within the range of ZnO additions x=0-1.0 wt.%, all the samples are of the typical characteristic of single-domain YBCO bulk; the Tc of the samples decreases from 92 K to 80 K when the ZnO addition x increases from x=0 wt.% to x=1.0 wt.%; the levitation force and trapped field of the samples firstly increase and then decrease with increase of ZnO additions after going through a maximum, which is closely related with the ZnO addition and the resulting flux pinning force caused by lattice distortion due to the substitution of Zn2+ for Cu2+ site in the YBCO crystal; the largest levitation force 36.8 N (77 K, 0.5 T) and trapped field 0.416 T (77 K, 0.5 T) of the samples are obtained when x=0.1 wt.%, respectively. This result is significantly important and helpful for us to improve the properties of YBCO bulk superconductors.

Measurement of AC Losses in a Racetrack Superconducting Coil Made from YBCO Coated Conductor

NASA Astrophysics Data System (ADS)

Seiler, Eugen; Abrahamsen, Asger B.; Kováč, Ján; Wichmann, Mike; Træholt, Chresten

We present the results of transport measurements of AC losses in a racetrack shaped superconducting coil made from coated conductor tape. The outer dimensions of the coil are approximately 24 cm × 12 cm and it has 57 turns. The coil is impregnated with epoxy resin and fiberglass tape is used to insulate the individual turns and to improve the mechanical properties of the epoxy when exposed to thermal cycling. The coil is manufactured as a part of the field winding of a small synchronous generator; therefore stainless steel frames are installed on the inner and outer side of the winding to reinforce it. The AC loss is measured versus the transport current Ia with the coil immersed in liquid nitrogen. Measurements at frequencies 21 Hz, 36 Hz and 72 Hz are compared. The AC losses follow Ia2 dependence at low current amplitudes and Ia3 at high amplitudes. After cutting the inner steel frame the low amplitude losses are decreased, their frequency dependence is reduced but their dependence on the current remains unchanged.

Possibility of material cost reduction toward development of low-cost second-generation superconducting wires

NASA Astrophysics Data System (ADS)

Ichinose, Ataru; Horii, Shigeru; Doi, Toshiya

2017-10-01

Two approaches to reducing the material cost of second-generation superconducting wires are proposed in this paper: (1) instead of the electrical stabilizing layers of silver and copper presently used on the superconducting layer, a Nb-doped SrTiO3 conductive buffer layer and cube-textured Cu are proposed as an advanced architecture, and (2) the use of an electromagnetic (EM) steel tape as a metal substrate of coated conductors in a conventional architecture. In structures fabricated without using electrical stabilizing layers on the superconducting layer, the critical current density achieved at 77 K in a self-field was approximately 2.6 MA/cm2. On the other hand, in the case of using EM steel tapes, although the critical current density was far from practical at the current stage, the biaxial alignment of YBa2Cu3O y (YBCO) and buffer layers was realized without oxidation on the metal surface. In this study, the possibility of material cost reduction has been strongly indicated toward the development of low-cost second-generation superconducting wires in the near future.

Levitation force of melt-textured YBCO superconductors under non-quasi-static situation

NASA Astrophysics Data System (ADS)

Zhao, Z. M.; Xu, J. M.; Yuan, X. Y.; Zhang, C. P.

2018-06-01

The superconducting levitation force of a simple superconductor-magnet system under non-quasi-static situation is investigated experimentally. Two yttrium barium copper oxide (YBCO) samples with different performances are chosen from two small batches of samples prepared by the top-seeded melt-textured growth process. The residual carbon content of the precursor powders of the two batches is different due to different heat treatment processes. During the experimental process for measuring the levitation force, the value of the relative speed between the YBCO sample and the permanent magnet is higher than that in conventional studies. The variation characteristics of the superconducting levitation force are analyzed and a crossing phenomenon in the force-displacement hysteresis curves is observed. The results indicate that the superconducting levitation force is different due to the different residual carbon contents. As residual carbon contents reduce, the crossing phenomenon is more obvious accordingly.

New method for introducing nanometer flux pinning centers into single domain YBCO bulk superconductors

NASA Astrophysics Data System (ADS)

Yang, W. M.; Wang, Miao

2013-10-01

Single domain YBCO superconductors with different additions of Bi2O3 have been fabricated by top seeded infiltration and growth process (TSIG). The effect of Bi2O3 additions on the growth morphology, microstructure and levitation force of the YBCO bulk superconductor has been investigated. The results indicate that single domain YBCO superconductors can be fabricated with the additions of Bi2O3 less than 2 wt%; Bi2O3 can be reacted with Y2BaCuO5 and liquid phase and finally form Y2Ba4CuBiOx(YBi2411) nanoscale particles; the size of the YBi2411 particles is about 100 nm, which can act as effective flux pinning centers. It is also found that the levitation force of single domain YBCO bulks is increasing from 13 N to 34 N and decreasing to 11 N with the increasing of Bi2O3 addition from 0.1 wt% to 0.7 wt% and 2 wt%. This result is helpful for us to improve the physical properties of REBCO bulk superconductors.

Roebel assembled coated conductor cables (RACC): Ac-Losses and current carrying potential

NASA Astrophysics Data System (ADS)

Frank, A.; Heller, R.; Goldacker, W.; Kling, A.; Schmidt, C.

2008-02-01

Low ac-loss HTS cables for transport currents well above 1 kA are required for application in transformers and generators and are taken into consideration for future generations of fusion reactor coils. Coated conductors (CC) are suitable candidates for high field application at an operation temperature in the range 50-77 K. Ac-field applications require cables with low ac-losses and hence twisting of the individual strands. We solved this problem using the Roebel technique. Short lengths of Roebel bar cables were prepared from industrial DyBCO and YBCO-CC. Meander shaped tapes of 4 or 5 mm width with twist pitches of 123 or 127 mm were cut from the 10 or 12 mm wide CC tapes using a specially designed tool. Eleven or twelve of these strands were assembled to a cable. The electrical and mechanical connection of the tapes was achieved using a silver powder filled conductive epoxy resin. Ac-losses of a short sample in an external ac-field were measured as a function of frequency and field amplitude as well as the coupling current decay time constant. We discuss the results in terms of available theories and compare measured time constants in transverse field with measured coupling losses. Finally the potential of this cable type for ac-use is discussed with respect to ac-losses and current carrying capability.

High T(sub c) superconductor/ferroelectric heterostructures

NASA Astrophysics Data System (ADS)

Ryder, Daniel F., Jr.

1994-12-01

Thin films of the ferroelectric perovskite, Ba(x) Sr(1-x) TiO3 (BST), were deposited on superconducting (100)YBa2Cu3O(x)(YBCO)/ (100)Yttria-stabilized zirconia(YSZ) substrates and (100)Si by ion-beam sputtering. Microstructural and compositional features of the ceramic bilayer were assessed by a combination of x-ray diffraction (XRD) and scanning electron microscopy. The films were smooth and featureless, and energy dispersive x-ray spectroscopy (EDX) data indicated that film composition closely matched target composition. XRD analysis showed that films deposited on YBCO substrates were highly c-axis textured, while the films deposited on (100)Si did not exhibit any preferred growth morphology. The superconducting properties of the YBCO substrate layer were maintained throughout the processing stages and, as such, it was demonstrated that ion beam sputtering is a viable method for the deposition of Ferroelectric/YBCO heterostructures.

Effect of grain-alignment on the levitation force of melt-processed YBCO bulk superconductors

NASA Astrophysics Data System (ADS)

Yang, Wan-min; Zhou, Lian; Feng, Yong; Zhang, Ping-xiang; Wu, Min-zhi; Wu, Xiao-zu; Gawalek, W.

1999-07-01

Single-domain YBCO bulk superconductors have been fabricated by Top Seeded Melt Slow Cooling Growth(TSSCG) process. Two typical YBCO cylinder samples with differential grain-alignment were selected for the investigation of the relationship between the grain-alignment and the levitation force under the same testing condition at liquid nitrogen temperature. It is found that the levitation force values is much different for the two samples, the levitation force of the sample with H par c-axis is more than two times higher than that of the samples with H ⊥ c-axis. So it is necessary to take account of this anisotropy in practical applications. The relationship between a magnet and a superconductor can be well described with a double exponential function. All the results are discussed in details.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stewart, Gary

The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1 st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2 nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. Amore » number of these modules are arranged in an m x n array to form the current-limiting matrix.« less

Structural and electrical properties of epitaxial YBCO films on Si (Abstract Only).

NASA Astrophysics Data System (ADS)

Fork, David K.; Barrera, A.; Phillips, Julia M.; Newman, N.; Fenner, David B.; Geballe, Theodore H.; Connell, G. A. N.; Boyce, James B.

1991-03-01

Efforts to grow high quality films of YBCO on Si have been complicated by factors discussed in Ref. 1, chief among them being the reaction between YBCO and Si, which is damaging even at 550 C. This is well below the customary temperatures for YBCO film growth. To avoid the reaction problem, epitaxial YBCO films were grown on Si (100) using an intermediate buffer layer of yttria-stabilized zirconia (YSZ).2 Both layers are grown via an entirely in situ process by pulsed laser deposition (PLD). Although the buffer layer prevents reaction, another problem arises; the large difference in thermal expansion coefficients between silicon and YBCO causes strain at room temperature. Thin (<500 A) YBCO films are unrelaxed and under tensile strain with a distorted unit cell. Thicker films are cracked and have poorer electrical properties. The thermal strain may be reduced by growing on silicon-on-sapphire (SOS) rather than silicon.3 This allows the growth of films of arbitrary thickness. Ion channeling reveals a high degree of crystalline perfection with a channeling minimum yield for Ba as low as 12% on either silicon or SOS. The normal state resistivity is 250-300 i-cm at 300 K; the critical temperature, Tc (R=0), is 86-88 K with a transition width (ATc) of I K. Critical current densities (J)°f 2x107 A/cm2 at 4.2 K and >2x106 A/cm2 at 77 K have been achieved. In addition, the surface resistance of a YBCO film on SOS was measured against Nb at 4.2 K. At 10 GHz, a value of 45 was obtained. This compares favorably to values reported for LaAlO3. Application of this technology to produce reaction patterned microstrip lines has been tested.4 This was done by ion milling away portions of the YSZ buffer layer prior to the YBCO deposition. YBCO landing on regions of exposed Si reacts to form an insulator. This technique was used to make 3 micron lines 1.5 mm long. The resulting structure had a Jc of l.6xl06 A/cm2 at 77 K. Isolation of separate structures exceeded 20 M. Several advantages of this technique are that no solvents, etchants or photoresist come into contact with the YBCO, hence this technique has a potential for operational-asgrown devices. In summary, it is now possible to produce YBCO films with structural and DC electrical properties which rival the most optimized c-axis epitaxial YBCO films on MgO, SrTiO3 and LaAlO3. Preliminary measurements of microwave properties appear promising. We thank Bruce Lairson for help obtaining magnetization data and Richard Johnson, Steve Ready and Lars-Erik Swartz for technical assistance. This work benefits from AFOSR (F49620-89-C-0017). DBF received support from NSF (DMR- 8822353). DKF acknowledges the AT&T scholarship.

RAPID COMMUNICATION: Large-area uniform ultrahigh-Jc YBa2Cu3O7-x film fabricated by the metalorganic deposition method using trifluoroacetates

NASA Astrophysics Data System (ADS)

Araki, Takeshi; Yamagiwa, Katsuya; Hirabayashi, Izumi; Suzuki, Katsumi; Tanaka, Shoji

2001-07-01

Ultrahigh-Jc YBa2Cu3O7-x (YBCO) films have been successfully fabricated by the metalorganic deposition method using a trifluoroacetate coating solution which is prepared by a newly developed purification technique, the solvent-into-gel (SIG) method. The prepared pure coating solution has less than 0.25% impurities and has a wide flexibility in process conditions to obtain high-Jc YBCO film. Using this feature, we have successfully formed 50 mm diameter YBCO films, which have a critical current density over 10 MA cm-2 (77 K, 0 T) on LaAlO3 single crystalline substrates.

Advanced development of TFA-MOD coated conductors

NASA Astrophysics Data System (ADS)

Rupich, M. W.; Li, X.; Sathyamurthy, S.; Thieme, C.; Fleshler, S.

2011-11-01

American Superconductor is manufacturing 2G wire for initial commercial applications. The 2G wire properties satisfy the requirements for these initial projects; however, improvements in the critical current, field performance and cost are required to address the broad range of potential commercial and military applications. In order to meet the anticipated the performance and cost requirements, AMSC's R&D effort is focused on two major areas: (1) higher critical current and (2) enhanced flux pinning. AMSC's current 2G production wire, designed around a 0.8 μm thick YBCO layer deposited by a Metal Organic Deposition (MOD) process, carries a critical current in the range of 200-300 A/cm-w (77 K, sf). Achieving higher critical current requires increasing the thickness of the YBCO layer. This paper describes recent progress at AMSC on increasing the critical current of MOD-YBCO films using processes compatible with low-cost, high-rate manufacturing.

Phase Evolution of YBa2Cu3O7-x films by all-chemical solution deposition route for coated conductors

NASA Astrophysics Data System (ADS)

Zhao, Yue; Tang, Xiao; Wu, Wei; Grivel, Jean-Claude

2014-05-01

In order to understand the all-chemical-solution-deposition (CSD) processes for manufacturing coated conductors, we investigated the phase evolution of YBa2Cu3O7 (YBCO) films deposited by a low-fluorine metal-organic solution deposition (LF-MOD) method on CSD derived Ce0.9La0.1O2/Gd2Zr2O7/NiW. It is shown that the phase transition from the pyrolyzed film to fully converted YBCO film in the LF-MOD process is similar to that in typical trifluoroacetates-metal organic deposition (TFA-MOD) processes even though the amount of TFA in the solution is reduced by almost one half compared with typical TFA-MOD cases. Moreover, we found that the formation of impurities (mainly BaCeO3, NiWO4 and NiO) is strongly related to the annealing temperature, i.e., the diffusion controlled reactions become intensive from 760 oC, which might be connected with the poor structural and superconducting properties of the films deposited at high sintering temperatures. Based on these results, the optimized growth conditions of YBCO films were established, and a high critical current density (Jc) of about 2 MA/cm2 (77 K, self field) is achieved in a 200 nm thick YBCO film in the architecture made by our all CSD route.

High performance YBCO films. Report for 1 August-31 October 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denlinger, E.J.; Fathy, A.; Kalokitis, D.

1992-10-31

The objective of this program is to identify suitable low loss, low dielectric constant substrates and develop and optimize deposition processes for high quality YBCO films including the necessary buffer layers. Ultimate goals are large area substrates having double-sided HTS coating with a surface resistance ten times lower than copper at 40 GHz. High quality HTS films on low dielectric constant substrates are expected to find widespread use in advanced millimeter wave components, in extending the power handling capability of microwave and millimeter wave circuitry, and in facilitating high speed computer interconnects. Sample demonstration circuits will be built toward themore » end of the program. We have successfully deposited a high quality YBCO film on a good low loss and low dielectric constant substrate, magnesium fluoride (e=5). With the use of two buffer layers (magnesium oxide and strontium titanate) between the YBCO and the substrate, transition temperatures of 89 deg K and transition widths of about 0.5 deg K were achieved. The critical current density Jc of 4 x 10 6 A/cm2 at 77K in zero field is among the highest reported for YBCO films. The magnesium fluoride (MgF2) substrate has a tetragonal structure with a dielectric constant of 5.2 in the plane of the substrate and 4.6 perpendicular to the substrate surface. It has a good harness (-575 Knoop) and a linear thermal expansion coefficient that closely matches YBCO and the buffer layers.« less

X-ray photoelectron spectroscopy characterization of a nonsuperconducting Y-Ba-Cu-O superconductor-normal-metal-superconductor barrier material

NASA Technical Reports Server (NTRS)

Vasquez, R. P.; Hunt, B. D.; Foote, M. C.; Bajuk, L. J.

1992-01-01

A film of a novel nonsuperconducting Y-Ba-Cu-O (YBCO) barrier material was grown using conditions similar to those reported by Agostinelli et al. (1991) for forming a cubic semiconducting (c-YBCO) phase, and the material was characterized using X-ray photoelectron spectroscopy (XPS). A comparison of the XPS spectra of this material to those obtained from the orthorhombic and tetragonal phases of YBCO (o-YBCO and t-YBCO, respectively) showed that the barrier material had spectral characteristics different from those of o-YBCO and t-YBCO, particularly in the O 1s region. Features associated with the Cu-O chain and surface-reconstructed Cu-O planes were absent, consistent with expectations for the simple perovskite crystal structure of c-YBCO proposed by Agostinelli et al.

Fabrication and characterization of La2Zr2O7 films on different buffer architectures for YBa2Cu3O7-δ coated conductors by RF magnetron sputtering.

PubMed

Xu, Da; Liu, Linfei; Xiao, Guina; Li, Yijie

2013-02-27

La2Zr2O7 (LZO) films were grown on different buffer architectures by radio frequency magnetron sputtering for the large-scale application of YBa2Cu3O7-x (YBCO)-coated conductors. The three different buffer architectures were cerium oxide (CeO2), yttria-stabilized zirconia (YSZ)/CeO2, and CeO2/YSZ/CeO2. The microstructure and surface morphology of the LZO film were studied by X-ray diffraction, optical microscopy, field emission scanning electron microscopy, and atomic force microscopy. The LZO films prepared on the CeO2, YSZ/CeO2, and CeO2/YSZ/CeO2 buffer architectures were preferentially c-axis-oriented and highly textured. The in-plane texture of LZO film on CeO2 single-buffer architecture was ∆ φ = 5.5° and the out-of-plane texture was ∆ ω = 3.4°. All the LZO films had very smooth surfaces, but LZO films grown on YSZ/CeO2 and CeO2/YSZ/CeO2 buffer architectures had cracks. The highly textured LZO film grown on CeO2-seed buffered NiW tape was suitable for the epitaxial growth of YBCO film with high currents.

Topography evolution of rough-surface metallic substrates by solution deposition planarization method

NASA Astrophysics Data System (ADS)

Chu, Jingyuan; Zhao, Yue; Liu, Linfei; Wu, Wei; Zhang, Zhiwei; Hong, Zhiyong; Li, Yijie; Jin, Zhijian

2018-01-01

As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50 × 50 μm2 scanning scale) on both rough substrates reduced to ∼5 nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high Jc value of 4.17 MA cm-2 (at 77 K, s.f.) was achieved on a full stack of YBCO/CeO2/IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture.

Vortex pinning landscape in MOD-TFA YBCO nanostroctured films

NASA Astrophysics Data System (ADS)

Gutierrez, J.; Puig, T.; Pomar, A.; Obradors, X.

2008-03-01

A methodology of general validity to study vortex pinning in YBCO based on Jc transport measurements is described. It permits to identify, separate and quantify three basic vortex pinning contributions associated to anisotropic-strong, isotropic-strong and isotropic-weak pinning centers. Thereof, the corresponding vortex pinning phase diagrams are built up. This methodology is applied to the new solution-derived YBCO nanostructured films, including controlled interfacial pinning by the growth of nanostructured templates by means of self-assembled processes [1] and YBCO-BaZrO3 nanocomposites prepared by modified solution precursors. The application of the methodology and comparison with a standard solution-derived YBCO film [2], enables us to identify the nature and the effect of the additional pinning centers induced. The nanostructured templates films show c-axis pinning strongly increased, controlling most of the pinning phase diagram. On the other hand, the nanocomposites have achieved so far, the highest pinning properties in HTc-superconductors [3], being the isotropic-strong defects contribution the origin of their unique properties. [1] M. Gibert et al, Adv. Mat. vol 19, p. 3937 (2007) [2] Puig.T et al, SuST EUCAS 2007 (to be published) [3] J. Gutierrez et al, Nat. Mat. vol. 6, p. 367 (2007) * Work supported by HIPERCHEM, NANOARTIS and MAT2005-02047

Strong Flux Pinning of Nano-Sized Ysz Particles in Ybco Films Prepared by Mod Method

NASA Astrophysics Data System (ADS)

Ye, S.; Suo, H. L.; Liu, M.; Tang, X.; Wu, Z. P.; Zhao, Y.; Zhou, M. L.

The YBCO films with doped YSZ nanoparticles have been prepared successfully by metal organic doepositon method using trifluoroacetates (TFA-MOD) through dissolving Zr organic salt into the YBCO precursor solution. The doped films have well in-plane and out-plane textures detected by both XRD Φ-scan and ω-scan. The YSZ nanoparticles with the size of about 5 ~ 15 nm were observed on the surface of the YBCO films using both FE-SEM and TEM. By comparing the superconducting properties, it was found that the doped YBCO films had lower Tc than that of undoped YBCO films. However, as increasing the applied magnetic field, Jc of the doped YBCO films were much better than that of undoped one. The Jc was as higher as 2.5 times than that of undoped YBCO film at 77 K and 1 T applied field.

Role of nano and micron-sized inclusions on the oxygen controlled preform optimized infiltration growth processed YBCO superconductors

NASA Astrophysics Data System (ADS)

Pavan Kumar Naik, S.; Bai, V. Seshu

2017-02-01

In the present work, with the aim of improving the local flux pinning at the unit cell level in the YBa2Cu3O7-δ (YBCO) bulk superconductors, 20 wt% of nanoscale Sm2O3 and micron sized (Nd, Sm, Gd)2BaCuO5 secondary phase particles were added to YBCO and processed in oxygen controlled preform optimized infiltration growth process. Nano Dispersive Sol Casting method is employed to homogeneously distribute the nano Sm2O3 particles of 30-50 nm without any agglomeration in the precursor powder. Microstructural investigations on doped samples show the chemical fluctuations as annuli cores in the 211 phase particles. The introduction of mixed rare earth elements at Y-site resulted in compositional fluctuations in the superconducting matrix. The associated lattice mismatch defects have provided flux pinning up to large magnetic fields. Magnetic field dependence of current density (Jc(H)) at different temperatures revealed that the dominant pinning mechanism is caused by spatial variations of critical temperatures, due to the spatial fluctuations in the matrix composition. As the number of rare earth elements increased in the YBCO, the peak field position in the scaling of the normalized pinning force density (Fp/Fp max) significantly gets shifted towards the higher fields. The curves of Jc(H) and Fp/Fp max at different temperatures clearly indicate the LRE substitution for LRE' or Ba-sites for δTc pinning.

Fabrication and characterization of hybrid Nb-YBCO dc SQUIDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frack, E.K.; Drake, R.E.; Patt, R.

This paper reports on the fabrication of hybrid low T{sub c}/high T{sub c} dc SQUIDs of two flavors. The first kind utilizes niobium tunnel junctions and a YBCO film strip as the most inductive portion of the SQUID loop. This configuration allows a direct measurement of the inductance of the YBCO microstrip from which the effective penetration depth can be calculated. The successful fabrication of these SQUIDs has required 1. superconducting Nb-to-YBCO contacts, 2. deposition and patterning of an SiO{sub 2} insulation layer over YBCO, and 3. selective patterning of niobium and SiO{sub 2} relative to YBCO. All these processmore » steps are pertinent to the eventual use of YBCO thin films in electronic devices.« less

Flux Pinning Enhancement in YBa2Cu3O7-x Films for Coated Conductor Applications (Postprint)

DTIC Science & Technology

2012-02-01

the nanocolumns with a certain constant diameter. Since BSO and YBCO are both perovskites, they tend to grow along the c - axis perpendicular to LAO ...20 0 20 40 60 80 100 YBCO+BaSnO 3 / LAO YBCO/MS-6 YBCO+BaSnO 3 /MS-6 J c /J c( h // a b ) Angle (Degs) H//C H//ab Figure 5.18 Transport current...density data of YBCO+BSO fi lm on a LaAlO 3 and a buffered metallic substrate as compared to YBCO fi lm on a metallic substrate. ( LAO = LaAlO 3 , MS

Origin of photovoltaic effect in superconducting YBa2Cu3O6.96 ceramics

PubMed Central

Yang, F.; Han, M. Y.; Chang, F. G.

2015-01-01

We report remarkable photovoltaic effect in YBa2Cu3O6.96 (YBCO) ceramic between 50 and 300 K induced by blue-laser illumination, which is directly related to the superconductivity of YBCO and the YBCO-metallic electrode interface. There is a polarity reversal for the open circuit voltage Voc and short circuit current Isc when YBCO undergoes a transition from superconducting to resistive state. We show that there exists an electrical potential across the superconductor-normal metal interface, which provides the separation force for the photo-induced electron-hole pairs. This interface potential directs from YBCO to the metal electrode when YBCO is superconducting and switches to the opposite direction when YBCO becomes nonsuperconducting. The origin of the potential may be readily associated with the proximity effect at metal-superconductor interface when YBCO is superconducting and its value is estimated to be ~10–8 mV at 50 K with a laser intensity of 502 mW/cm2. Combination of a p-type material YBCO at normal state with an n-type material Ag-paste forms a quasi-pn junction which is responsible for the photovoltaic behavior of YBCO ceramics at high temperatures. Our findings may pave the way to new applications of photon-electronic devices and shed further light on the proximity effect at the superconductor-metal interface. PMID:26099727

Surface flux density distribution characteristics of bulk high- Tc superconductor in external magnetic field

NASA Astrophysics Data System (ADS)

Torii, S.; Yuasa, K.

2004-10-01

Various magnetic levitation systems using oxide superconductors are developed as strong pinning forces are obtained in melt-processed bulk. However, the trapped flux of superconductor is moved by flux creep and fluctuating magnetic field. Therefore, to examine the internal condition of superconductor, the authors measure the dynamic surface flux density distribution of YBCO bulk. Flux density measurement system has a structure with the air-core coil and the Hall sensors. Ten Hall sensors are arranged in series. The YBCO bulk, which has 25 mm diameter and 13 mm thickness, is field cooled by liquid nitrogen. After that, magnetic field is changed by the air-core coil. This paper describes about the measured results of flux density distribution of YBCO bulk in the various frequencies of air-core coils currents.

A novel pre-sintering technique for the growth of Y-Ba-Cu-O superconducting single grains from raw metal oxides

NASA Astrophysics Data System (ADS)

Li, Jiawei; Shi, Yun-Hua; Dennis, Anthony R.; Namburi, Devendra Kumar; Durrell, John H.; Yang, Wanmin; Cardwell, David A.

2017-09-01

Most established top seeded melt growth (TSMG) processes of bulk, single grain Y-Ba-Cu-O (YBCO) superconductors are performed using a mixture of pre-reacted precursor powders. Here we report the successful growth of large, single grain YBCO samples by TSMG with good superconducting properties from a simple precursor composition consisting of a sintered mixture of the raw oxides. The elimination of the requirement to synthesize precursor powders in a separate process prior to melt processing has the potential to reduce significantly the cost of bulk superconductors, which is essential for their commercial exploitation. The growth morphology, microstructure, trapped magnetic field and critical current density, J c, at different positions within the sample and maximum levitation force of the YBCO single grains fabricated by this process are reported. Measurements of the superconducting properties show that the trapped filed can reach 0.45 T and that a zero field J c of 2.5 × 104 A cm-2 can be achieved in these samples. These values are comparable to those observed in samples fabricated using pre-reacted, high purity commercial oxide precursor powders. The experimental results are discussed and the possibility of further improving the melt process using raw oxides is outlined.

Processing of large grain Y-123 superconductors with pre-defined porous structures

NASA Astrophysics Data System (ADS)

Sudhakar Reddy, E.; Babu, N. Hari; Shi, Y.; Cardwell, D. A.; Schmitz, G. J.

2005-02-01

Porous superconductors have inherent cooling advantages over their bulk counterparts and, as a result, are emerging as an important class of materials for practical applications. Single-domain Y-Ba-Cu-O (YBCO) foams processed with a pre-defined, open porous structure, for example, have significant potential for use as elements in resistive superconducting fault current limiters. In this case, the interconnected porosity is ideal for producing reinforced composites with improved mechanical and heat conducting properties. In this paper we describe a few simple methods for fabricating large grain YBCO superconductors with various predefined porous structures via an infiltration process from tailored, porous Y2BaCuO5 (Y-211) pre-forms manufactured by a variety of techniques, including slurry-coating of standard polyurethane foams to replicate their structure. Foams produced by this method typically have a strut thickness of a few hundred µm and pore sizes ranging from 10 to 100 pores per inch (PPI). Foams with increased strut thickness of up to millimetre dimensions can be produced by embedding organic ball spacers within the Y-211 pre-form followed by a burn-out and sintering process. Single-domain YBCO bulk materials with cellular and pre-defined 3D interconnected porosity may be produced by a similar process using tailored wax structures in Y-211 castings.

Development of an YBCO coil with SSTC conductors for high field application

NASA Astrophysics Data System (ADS)

Shi, Y.; Liu, H. J.; Liu, F.; Tan, Y. F.; Jin, H.; Yu, M.; Lei, L.; Guo, L.; Hong, Z. Y.

2018-07-01

With the continuous reduction of the production costs and improvement of the transport performance, YBCO coated conductor is the most promising candidate for the high field magnet application due to its high irreversibility field and strong mechanical properties. Presently a stable production capacity of the YBCO conductors has been achieved by Shanghai Superconducting Technology Co., Ltd (SSTC) in China. Therefore, the demand in high field application with YBCO conductors is growing in China. This paper describes the design, fabrication and preliminary experiment of a solenoid coil with YBCO conductors supplied by SSTC to validate the possibility of high field application. Four same double pancakes were manufactured and assembled for the YBCO coil where the outer diameter and height was 54.3 and 48 mm respectively to match the dimensional limitation of the 14 T background magnets. The critical current (Ic) of YBCO conductors was obtained by measuring as a function of the applied field perpendicular to the YBCO conductor surface which provides the necessary input parameters for preliminary performance evaluation of the coil. Finally the preliminary test and discussion at 77 and 4.2 K were carried out. The consistency of four double pancakes Ic was achieved. The measured results indicate that the fabrication technology of HTS coil is reliable which gives the conference for the in-field test in high field application. This YBCO coil is the first demonstration of the SSTC YBCO coated conductors.

In Situ deposition of YBCO high-T(sub c) superconducting thin films by MOCVD and PE-MOCVD

NASA Technical Reports Server (NTRS)

Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P.; Gallois, B.; Kear, B.

1990-01-01

Metalorganic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T( sub c) greater than 90 K and Jc approx. 10 to the 4th power A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metalorganic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

In-situ deposition of YBCO high-Tc superconducting thin films by MOCVD and PE-MOCVD

NASA Technical Reports Server (NTRS)

Zhao, J.; Noh, D. W.; Chern, C.; Li, Y. Q.; Norris, P. E.; Kear, B.; Gallois, B.

1991-01-01

Metal-Organic Chemical Vapor Deposition (MOCVD) offers the advantages of a high degree of compositional control, adaptability for large scale production, and the potential for low temperature fabrication. The capability of operating at high oxygen partial pressure is particularly suitable for in situ formation of high temperature superconducting (HTSC) films. Yttrium barium copper oxide (YBCO) thin films having a sharp zero-resistance transition with T(sub c) greater than 90 K and J(sub c) of approximately 10(exp 4) A on YSZ have been prepared, in situ, at a substrate temperature of about 800 C. Moreover, the ability to form oxide films at low temperature is very desirable for device applications of HTSC materials. Such a process would permit the deposition of high quality HTSC films with a smooth surface on a variety of substrates. Highly c-axis oriented, dense, scratch resistant, superconducting YBCO thin films with mirror-like surfaces have been prepared, in situ, at a reduced substrate temperature as low as 570 C by a remote microwave-plasma enhanced metal-organic chemical vapor deposition (PE-MOCVD) process. Nitrous oxide was used as a reactant gas to generate active oxidizing species. This process, for the first time, allows the formation of YBCO thin films with the orthorhombic superconducting phase in the as-deposited state. The as-deposited films grown by PE-MOCVD show attainment of zero resistance at 72 K with a transition width of about 5 K. MOCVD was carried out in a commercial production scale reactor with the capability of uniform deposition over 100 sq cm per growth run. Preliminary results indicate that PE-MOCVD is a very attractive thin film deposition process for superconducting device technology.

Atom-replaced pins in a Y-based superconductor—single-crystalline perovskite structure including both PrBa2Cu3O7‑x and YBa2Cu3O7‑y

NASA Astrophysics Data System (ADS)

Hayashi, Mariko; Araki, Takeshi; Ishii, Hirotaka; Nishijima, Gen; Matsumoto, Akiyoshi

2018-05-01

Metal organic deposition using trifluoroacetates (TFA-MOD) provides many uniform superconductors on long metal tapes. The large numbers of long wires have been applied for power grids or superconducting fault current limiters. The related applications worked for a long time without fatal trouble. The quasi-liquid produced during the firing process assisted the perfectly uniform structure in TFA-MOD. On the other hand, when it was desired to introduce artificial pinning centers, the quasi-liquid also enlarged the diameter of the artificial pinning centers to several tens of nanometers. In other words, due to the nature of TFA-MOD, there is very little chance of using TFA-MOD to prepare several nm-sized artificial pinning centers. By proposing atom-replaced pins (ARPs), we aim to overcome the impasse. ARPs are realized by replacing yttrium (Y) with praseodymium (Pr) whose valence number changes from 3+ to approximately 4+. Analytical results suggested that Pr makes pinning centers on a PrBa2Cu3O7‑x (PrBCO) unit cell, and the weak-linked superconductivity derived from PrBCO extends to the adjacent unit cells in the a/b-plane. J c decrease by Pr is five times as large as the volume fraction of Pr in the Y-site of the perovskite structure. On the other hand, T c does not show large degradation in YBCO including 10% PrBCO. These results suggest that PrBCO unit cells are fully dispersed in YBa2Cu3O7‑y matrix. With regard to J c in the magnetic field, (Y0.98, Pr0.02)BCO has been slightly improved compared with pure YBCO only in the region of high temperature and low magnetic field of less than 1 T.

Improved epitaxial texture of thick YBa2Cu3O7-δ/GdBa2Cu3O7-δ films with periodic stress releasing

NASA Astrophysics Data System (ADS)

Lin, Jianxin; Yang, Wentao; Gu, Zhaohui; Shu, Gangqiang; Li, Minjuan; Sang, Lina; Guo, Yanqun; Liu, Zhiyong; Cai, Chuanbing

2015-04-01

Thick high-Tc superconducting films consisting of a YBa2Cu3O7-δ/GdBa2Cu3O7-δ periodic architecture are developed on oxid-buffered Hastelloy tapes using a pulsed laser deposition process. It is revealed that multilayer intermittent structures for superconducting layers are effective to avoid the presence of a-axis grains and microcracks that occur with increasing thickness, which are frequently observed in monolayer films of REBa2Cu3O7-δ (RE = Y, Gd, or other rare earths), such grains and cracks being the significant challenge for obtaining high critical current in coated conductors. Presently, the thicknesses of multilayer films vary from 0.5 μm to 3 μm and, based on the SEM images and x-ray φ-scans, hardly show the influences on the microstructures and grain orientation of the c-axis. Also, the characteristic Raman spectrum patterns and their shifting with increasing the thickness of YBCO/GdBCO imply that the superior texture is obtained due to the evolution of stress dominated by the compressive stress rather than tensile stress.

Acid anhydrides: a simple route to highly pure organometallic solutions for superconducting films

NASA Astrophysics Data System (ADS)

Roma, N.; Morlens, S.; Ricart, S.; Zalamova, K.; Moreto, J. M.; Pomar, A.; Puig, T.; Obradors, X.

2006-06-01

The presence of impurities in the precursor metal carboxylate solutions for the preparation of epitaxial thin films by metal organic decomposition (MOD) is substantially avoided by the use of acid anhydrides. In particular, trifluoroacetic anhydride (TFAA) was used for the synthesis of the starting Y, Ba and Cu trifluoroacetates used in YBa2Cu3O7-x (YBCO) preparation by the MOD process. In this way, highly stable organometallic precursors and a short pyrolysis process could be used leading to YBCO films with high critical currents (Jc >=2-4 MA cm-2 at 77 K). Furthermore, the reproducibility of the results has been ascertained.

High quality uniform YBCO film growth by the metalorganic deposition using trifluoroacetates

NASA Astrophysics Data System (ADS)

Wang, S. S.; Zhang, Z. L.; Wang, L.; Gao, L. K.; Liu, J.

2017-03-01

A need exists for the large-area superconducting YBa2Cu3O7-x (YBCO) films with high critical current density for microwave communication and/or electric power applications. Trifluoroacetic metalorganic (TFA-MOD) method is a promising low cost technique for large-scale production of YBCO films, because it does not need high vacuum device and is easily applicable to substrates of various shape and size. In this paper, double-sided YBCO films with maximum 2 in diameter were prepared on LaAlO3 substrates by TFA-MOD method. Inductive critical current densitiy Jc, microwave surface resistance Rs, as well as the microstructure were characterized. A newly homemade furnace system was used to epitaxially grown YBCO films, which can improve the uniformity of YBCO film significantly by gas supply and temperature distribution proper design. Results showed that the large area YBCO films were very uniform in microstructure and thickness distribution, an average inductive Jc in excess of 6 MA/cm2 with uniform distribution, and low Rs (10 GHz) below 0.3 mΩ at 77 K were obtained. Andthe film filter may be prepared to work at temperatures lower than 74 K. These results are very close to the highest value of YBCO films made by conventional vacuum method, so we show a very promising route for large-scale production of high quality large-area YBCO superconducting films at a lower cost.

The effect of growth temperature on the irreversibility line of MPMG YBCO bulk with Y2O3 layer

NASA Astrophysics Data System (ADS)

Kurnaz, Sedat; Çakır, Bakiye; Aydıner, Alev

2017-07-01

In this study, three kinds of YBCO samples which are named Y1040, Y1050 and Y1060 were fabricated by Melt-Powder-Melt-Growth (MPMG) method without a seed crystal. Samples seem to be single crystal. The compacted powders were located on a crucible with a buffer layer of Y2O3 to avoid liquid to spread on the furnace plate and also to support crystal growth. YBCO samples were investigated by magnetoresistivity (ρ-T) and magnetization (M-T) measurements in dc magnetic fields (parallel to c-axis) up to 5 T. Irreversibility fields (Hirr) and upper critical fields (Hc2) were obtained using 10% and 90% criteria of the normal state resistivity value from ρ-T curves. M-T measurements were carried out using the zero field cooling (ZFC) and field cooling (FC) processes to get irreversible temperature (Tirr). Fitting of the irreversibility line results to giant flux creep and vortex glass models were discussed. The results were found to be consistent with the results of the samples fabricated using a seed crystal. At the fabrication of MPMG YBCO, optimized temperature for crystal growth was determined to be around 1050-1060 °C.

High trapped fields in bulk YBCO superconductors

NASA Astrophysics Data System (ADS)

Fuchs, Günter; Gruss, Stefan; Krabbes, Gernot; Schätzle, Peter; Verges, Peter; Müller, Karl-Hartmut; Fink, Jörg; Schultz, Ludwig

The trapped field properties of bulk melt-textured YBCO material were investigated at different temperatures. In the temperature range of liquid nitrogen, maximum trapped fields of 1.1 T were found at 77 K by doping of YBCO with small amounts of zinc. The improved pinning of zinc-doped YBa2Cu3O7-x (YBCO) results in a pronounced peak effect in the field dependence of the critical current density. the trapped field at lower temperatures increases due to the increasing critical current density, however, at temperatures around 50 K cracking of the material is observed which is exposed to considerably tensile stresses due to Lorentz forces. Very high trapped fields up to 14.4 T were achieved at 22.5 K for a YBCO disk pair by the addition of silver improving the tensile strength of YBCO and by using a bandage made of a steel tube. The steel tube produces a compressive stress on YBCO after cooling down from 300 K to the measuring temperature, which is due to the higher coeeficient of thermal expansion of steel compared with that of YBCO in the a,b plane. The application of superconducting permanent magnets with trapped fields of 10 T and more in superconducting bearings would allow to obtain very high levitation pressures up to 2500 N/cm2 which is two orders of magnitude higher than the levitation pressure achievable in superconducting bearings with conventional permanent magnets. The most important problem for the application of superconducting permanent magnets is the magnetizing procedure of the YBCO material. Results of magnetizing YBCO disks by using of pulsed magnetic fields will be presented.

Microstructure and property correlations in high-temperature superconductors

NASA Astrophysics Data System (ADS)

Kalyanaraman, Ramakrishnan

1998-11-01

The work in this dissertation is intended at developing high quality device gradefilms of the high temperature (high-Tsbc) superconductor, Yttrium Barium Copper Oxide (YBCO), on MgO(001) substrates. Three approaches have been used to achieve the above goal, (i) The use of a SrTiOsb3 buffer layer, (ii) The use of Ag to enhance the growth of YBCO films and (iii) Investigation of the atomic structure-property correlations of low-angle grain boundaries in these films. Thin film heterostructures of YBCO/MgO and YBCO/SrTiOsb3/MgO were fabricated by pulsed laser deposition (PLD), using a 248 nm KrF excimer laser. Analysis of the structure and measurement of superconducting properties of the films were carried out to optimize the suitable conditions under each approach. The key findings were, (i) Single crystal-like SrTiOsb3 buffer layers can be grown and they give the highest JsbcYBCO films, (ii) An in-depth study of the role of Ag showed that it enhanced film growth of YBCO thereby improving its quality, and (iii) Low-angle boundaries in YBCO/MgO occur with two probable habit planes and the Jsbcs across them differ slightly. A systematic investigation of the crystalline quality of the SrTiOsb3 films deposited by PLD was performed as a function of oxygen partial pressure (pOsb2) and substrate temperature (Tsbc). The highest quality films were grown in the pOsb2 range of 0.1-1 mTorr at 750sp°C. The films had as-deposited x-ray diffraction rocking curve (omega) values of {˜}0.70sp° and Rutherford backscattering channeling yields (chisbmin) of 5% as compared to omega˜1.40sp° and chisbmin˜14% for the film deposited in 100 mTorr of pOsb2. The x-ray phi-scans showed epitaxial cube-on-cube alignment of the SrTiOsb3 films on MgO(001) substrates. Thermal annealing of the SrTiOsb3 films further improved the quality, and the 1 mTorr films gave omega{˜}0.13sp° and chisbmin˜2.0%. Transmission electron microscopy investigations (TEM) of these films showed that the defects in films grown in the pOsb2 range of 0.5-1 mTorr consisted mainly of dislocations and sub-grain boundaries, while those grown in the higher pOsb2 contained numerous low-angle grain boundaries. YBCO films grown on the best SrTiOsb3 buffer layers showed reproducible Jsbcs of {˜}5.5× 10sp6 amps/cmsp2 at 77K and Tsbcs of 88-91K. The YBCO films was observed to grow epitaxially on SrTiOsb3 with (110) sbPYBCO//(110) sbSriTiO3 and (001) sbYBCO//(001) sbSrTiO3{*}chisbmin for the best YBCO film was ˜2.8%. The crystalline quality of the SrTiOsb3 and YBCO films developed are amongst the highest reported so far. Composite targets of Ag+YBCO were used to grow YBCO films using PLD. Using XRD and Tsbc measurements clear evidence for enhanced oxygenation of the YBCO films was shown. Detailed TEM investigation of grain boundaries in YBCO/MgO(001) showed that the low-angle grain boundaries in YBCO are equally likely to have (100) or (110) habit planes. (Abstract shortened by UMI.)

Critical Current Properties in Longitudinal Magnetic Field of YBCO Superconductor with APC

NASA Astrophysics Data System (ADS)

Kido, R.; Kiuchi, M.; Otabe, E. S.; Matsushita, T.; Jha, A. K.; Matsumoto, K.

The critical current density (Jc) properties of the Artificial Pinning Center (APC) introduced YBa2Cu3O7 (YBCO) films in the longitudinal magnetic field were measured. Y2O3 or Y2BaCuO5 (Y211) was introduced as APCs to YBCO, and YBCO films with APC were fabricated on SrTiO3 single crystal substrate. The sizes of Y2O3 and Y211 were 5-10 nm and 10-20 nm, respectively. As a result, Jc enhancement in the longitudinal magnetic field was observed in Y2O3 introduced YBCO films. However, it was not observed in Y211 introduced YBCO films. Therefore, it was considered that Jc properties in the longitudinal magnetic field were affected by introducing of small size APC, and it was necessary that APC does not disturb the current pathway in the superconductor.

Ultrafast relaxation dynamics in BiFeO 3/YBa 2Cu 3O 7 bilayers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Springer, D.; Nair, Saritha K.; He, Mi

The temperature dependence of the relaxation dynamics in the bilayer thin film heterostructure composed of multiferroic BiFeO 3 (BFO) and superconducting YBa 2Cu 3O 7 (YBCO) grown on (001) SrTiO 3 substrate is studied by time-resolved pump-probe technique, and compared with that of pure YBCO thin film grown under the same growth conditions. The superconductivity of YBCO is found to be retained in the heterostructure. We observe a speeding up of the YBCO recombination dynamics in the superconducting state of the heterostructure, and attribute it to the presence of weak ferromagnetism at the BFO/YBCOinterface as observed inmagnetization data. An extensionmore » of the Rothwarf-Taylor model is used to fit the ultrafast dynamics of BFO/YBCO, that models an increased quasiparticle occupation of the ferromagnetic interfacial layer in the superconducting state of YBCO.« less

Ultrafast relaxation dynamics in BiFeO 3/YBa 2Cu 3O 7 bilayers

DOE PAGES

Springer, D.; Nair, Saritha K.; He, Mi; ...

2016-02-12

The temperature dependence of the relaxation dynamics in the bilayer thin film heterostructure composed of multiferroic BiFeO 3 (BFO) and superconducting YBa 2Cu 3O 7 (YBCO) grown on (001) SrTiO 3 substrate is studied by time-resolved pump-probe technique, and compared with that of pure YBCO thin film grown under the same growth conditions. The superconductivity of YBCO is found to be retained in the heterostructure. We observe a speeding up of the YBCO recombination dynamics in the superconducting state of the heterostructure, and attribute it to the presence of weak ferromagnetism at the BFO/YBCOinterface as observed inmagnetization data. An extensionmore » of the Rothwarf-Taylor model is used to fit the ultrafast dynamics of BFO/YBCO, that models an increased quasiparticle occupation of the ferromagnetic interfacial layer in the superconducting state of YBCO.« less

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2013 CFR

2013-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2014 CFR

2014-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2010 CFR

2010-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2012 CFR

2012-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

41 CFR 101-26.508 - Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band).

Code of Federal Regulations, 2011 CFR

2011-07-01

... processing (EDP) tape and instrumentation tape (wide and intermediate band). 101-26.508 Section 101-26.508... Programs § 101-26.508 Electronic data processing (EDP) tape and instrumentation tape (wide and intermediate band). Procurement by Federal agencies of EDP tape and instrumentation tape (wide and intermediate band...

High performance YBCO films. Quarterly status report No. 6, 1 February-30 April 1993. [YBCO (yttrium barium copper oxides)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denlinger, E.J.; Fathy, A.; Kalokitis, D.

1993-04-30

YBCO on MgF2 withstood post annealing to 750 deg C without deterioration. This allows the deposition of high quality multiple layer YBCO films onto both sides of a MgF2 substrate. GdBaCuO films were deposited onto LaAlO3 and appear to be superior to YBCO in terms of lower particulate density, slightly higher T[sub c]'s, and higher critical current density. The ramifications could be very beneficial to the MCM program. Furthermore, the tolerance of these films to a wider range of deposition conditions indicates a possibility of using these films on MgF2.

Fabrication of biaxially oriented YBCO on (001) biaxially oriented yttria-stabilized-zirconia on polycrystalline substrates

NASA Astrophysics Data System (ADS)

Arendt, P.; Foltyn, S.; Wu, Xin Di; Townsend, J.; Adams, C.; Hawley, M.; Tiwari, P.; Maley, M.; Willis, J.; Moseley, D.

Ion-assisted, ion-beam sputter deposition is used to obtain (001) biaxially oriented films of cubic yttria stabilized zirconia (YSZ) on polycrystalline metal substrates. Yttrium barium copper oxide (YBCO) is then heteroepitaxially pulse laser deposited onto the YSZ. Phi scans of the films show the full-width-half maxima of the YSZ (202) and the YBCO (103) reflections to be 14 deg and 10 deg, respectively. Our best dc transport critical current density measurement for the YBCO is 800,000 A/sq cm at 75 K and 0 T. At 75 K, the total dc transport current in a 1 cm wide YBCO film is 23 A.

Magnetoresistivity and microstructure of YBa2Cu3Oy prepared using planetary ball milling

NASA Astrophysics Data System (ADS)

Hamrita, A.; Ben Azzouz, F.; Madani, A.; Ben Salem, M.

2012-01-01

We have studied the microstructure and the magnetoresistivity of polycrystalline YBa2Cu3Oy (YBCO or Y-123 for brevity) embedded with nanoparticles of Y-deficient YBCO, generated by the planetary ball milling technique. Bulk samples were synthesized from a precursor YBCO powder, which was prepared from commercial high purity Y2O3, Ba2CO3 and CuO via a one-step annealing process in air at 950 °C. After planetary ball milling of the precursor, the powder was uniaxially pressed and subsequently annealed at 950 °C in air. Phase analysis by X-ray diffraction (XRD), granular structure examination by scanning electron microscopy (SEM), microstructure investigation by transmission electron microscopy (TEM) coupled with energy dispersive X-ray spectroscopy (EDXS) were carried out. TEM analyses show that nanoparticles of Y-deficient YBCO, generated by ball milling, are embedded in the superconducting matrix. Electrical resistance as a function of temperature, ρ(T), revealed that the zero resistance temperature, Tco, is 84.5 and 90 K for the milled and unmilled samples respectively. The milled ceramics exhibit a large magnetoresistance in weak magnetic fields at liquid nitrogen temperature. This attractive effect is of high significance as it makes these materials promising candidates for practical application in magnetic field sensor devices.

Flux cutting in high- T c superconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlasko-Vlasov, V.; Koshelev, A.; Glatz, A.

We performed magneto-optical study of flux distributions in a YBCO crystal under various applied crossed- field orientations to elucidate the complex nature of magnetic flux cutting in superconductors. Our study reveals unusual vortex patterns induced by the interplay between flux-cutting and vortex pinning. We observe strong flux penetration anisotropy of the normal flux B⊥ in the presence of an in-plane field H|| and associate the modified flux dynamics with staircase structure of tilted vortices in YBCO and the flux-cutting process. We demonstrate that flux-cutting can effectively delay vortex entry in the direction transverse to H||. Finally, we elucidate details ofmore » the vortex-cutting and reconnection process using time-dependent Ginzburg-Landau simulations.« less

Strategy for robot motion and path planning in robot taping

NASA Astrophysics Data System (ADS)

Yuan, Qilong; Chen, I.-Ming; Lembono, Teguh Santoso; Landén, Simon Nelson; Malmgren, Victor

2016-06-01

Covering objects with masking tapes is a common process for surface protection in processes like spray painting, plasma spraying, shot peening, etc. Manual taping is tedious and takes a lot of effort of the workers. The taping process is a special process which requires correct surface covering strategy and proper attachment of the masking tape for an efficient surface protection. We have introduced an automatic robot taping system consisting of a robot manipulator, a rotating platform, a 3D scanner and specially designed taping end-effectors. This paper mainly talks about the surface covering strategies for different classes of geometries. The methods and corresponding taping tools are introduced for taping of following classes of surfaces: Cylindrical/extended surfaces, freeform surfaces with no grooves, surfaces with grooves, and rotational symmetrical surfaces. A collision avoidance algorithm is introduced for the robot taping manipulation. With further improvements on segmenting surfaces of taping parts and tape cutting mechanisms, such taping solution with the taping tool and the taping methodology can be combined as a very useful and practical taping package to assist humans in this tedious and time costly work.

High temperature superconducting YBCO microwave filters

NASA Astrophysics Data System (ADS)

Aghabagheri, S.; Rasti, M.; Mohammadizadeh, M. R.; Kameli, P.; Salamati, H.; Mohammadpour-Aghdam, K.; Faraji-Dana, R.

2018-06-01

Epitaxial thin films of YBCO high temperature superconductor are widely used in telecommunication technology such as microwave filter, antenna, coupler and etc., due to their lower surface resistance and lower microwave loss than their normal conductor counterparts. Thin films of YBCO were fabricated by PLD technique on LAO substrate. Transition temperature and width were 88 K and 3 K, respectively. A filter pattern was designed and implemented by wet photolithography method on the films. Characterization of the filter at 77 K has been compared with the simulation results and the results for a made gold filter. Both YBCO and gold filters show high microwave loss. For YBCO filter, the reason may be due to the improper contacts on the feedlines and for gold filter, low thickness of the gold film has caused the loss increased.

Maximum permissible voltage of YBCO coated conductors

NASA Astrophysics Data System (ADS)

Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z.; Hong, Z.; Wang, D.; Zhou, H.; Shen, X.; Shen, C.

2014-06-01

Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

Proximity effects across oxide-interfaces of superconductor-insulator-ferromagnet hybrid heterostructure.

PubMed

Prajapat, C L; Singh, Surendra; Bhattacharya, D; Ravikumar, G; Basu, S; Mattauch, S; Zheng, Jian-Guo; Aoki, T; Paul, Amitesh

2018-02-27

A case study of electron tunneling or charge-transfer-driven orbital ordering in superconductor (SC)-ferromagnet (FM) interfaces has been conducted in heteroepitaxial YBa 2 Cu 3 O 7 (YBCO)/La 0.67 Sr 0.33 MnO 3 (LSMO) multilayers interleaved with and without an insulating SrTiO 3 (STO) layer between YBCO and LSMO. X-ray magnetic circular dichroism experiments revealed anti-parallel alignment of Mn magnetic moments and induced Cu magnetic moments in a YBCO/LSMO multilayer. As compared to an isolated LSMO layer, the YBCO/LSMO multilayer displayed a (50%) weaker Mn magnetic signal, which is related to the usual proximity effect. It was a surprise that a similar proximity effect was also observed in a YBCO/STO/LSMO multilayer, however, the Mn signal was reduced by 20%. This reduced magnetic moment of Mn was further verified by depth sensitive polarized neutron reflectivity. Electron energy loss spectroscopy experiment showed the evidence of Ti magnetic polarization at the interfaces of the YBCO/STO/LSMO multilayer. This crossover magnetization is due to a transfer of interface electrons that migrate from Ti (4+)-δ to Mn at the STO/LSMO interface and to Cu 2+ at the STO/YBCO interface, with hybridization via O 2p orbitals. So charge-transfer driven orbital ordering is the mechanism responsible for the observed proximity effect and Mn-Cu anti-parallel coupling in YBCO/STO/LSMO. This work provides an effective pathway in understanding the aspect of long range proximity effect and consequent orbital degeneracy parameter in magnetic coupling.

Analysis of YBCO high temperature superconductor doped with silver nanoparticles and carbon nanotubes using Williamson-Hall and size-strain plot

NASA Astrophysics Data System (ADS)

Dadras, Sedigheh; Davoudiniya, Masoumeh

2018-05-01

This paper sets out to investigate and compare the effects of Ag nanoparticles and carbon nanotubes (CNTs) doping on the mechanical properties of Y1Ba2Cu3O7-δ (YBCO) high temperature superconductor. For this purpose, the pure and doped YBCO samples were synthesized by sol-gel method. The microstructural analysis of the samples is performed using X-ray diffraction (XRD). The crystalline size, lattice strain and stress of the pure and doped YBCO samples were estimated by modified forms of Williamson-Hall analysis (W-H), namely, uniform deformation model (UDM), uniform deformation stress model (UDSM) and the size-strain plot method (SSP). These results show that the crystalline size, lattice strain and stress of the YBCO samples declined by Ag nanoparticles and CNTs doping.

Greatly enhanced flux pinning properties of fluorine-free metal-organic decomposition YBCO films by co-addition of halogens (Cl, Br) and metals (Zr, Sn, Hf)

NASA Astrophysics Data System (ADS)

Motoki, Takanori; Ikeda, Shuhei; Nakamura, Shin-ichi; Honda, Genki; Nagaishi, Tatsuoki; Doi, Toshiya; Shimoyama, Jun-ichi

2018-04-01

Additive-free YBCO films, as well as those with halogen (X) added, metal (M) added and (X, M) co-added, have been prepared by the fluorine-free metal-organic decomposition method on SrTiO3(100) single crystalline substrates, where X = Cl, Br and M = Zr, Sn, Hf. It was revealed that the addition of both Cl and Br to the starting solution resulted in the generation of oxyhalide, Ba2Cu3O4 X 2, in the YBCO films, and that the oxyhalide was found to promote the bi-axial orientation of the YBCO crystals. By adding a decent amount of Cl or Br, highly textured YBCO films with high J c were reproducibly obtained, even when an impurity metal, M, was co-added, while the addition of M without X did not greatly improve J c owing to the poor bi-axial orientation of the YBCO crystals. Our results suggest that the addition of Br more effectively enhances J c than the addition of Cl. The pinning force density at 40 K in 4.8 T reached ˜55 GN m-3 with the co-addition of (Br, M). This value is much larger than that of the pure YBCO film, reaching ˜17 GN m-3.

Over-current carrying characteristics of rectangular-shaped YBCO thin films prepared by MOD method

NASA Astrophysics Data System (ADS)

Hotta, N.; Yokomizu, Y.; Iioka, D.; Matsumura, T.; Kumagai, T.; Yamasaki, H.; Shibuya, M.; Nitta, T.

2008-02-01

A fault current limiter (FCL) may be manufactured at competitive qualities and prices by using rectangular-shaped YBCO films which are prepared by metal-organic deposition (MOD) method, because the MOD method can produce large size elements with a low-cost and non-vacuum technique. Prior to constructing a superconducting FCL (SFCL), AC over-current carrying experiments were conducted for 120 mm long elements where YBCO thin film of about 200 nm in thickness was coated on sapphire substrate with cerium oxide (CeO2) interlayer. In the experiments, only single cycle of the ac damping current of 50 Hz was applied to the pure YBCO element without protective metal coating or parallel resistor and the magnitude of the current was increased step by step until the breakdown phenomena occurred in the element. In each experiment, current waveforms flowing through the YBCO element and voltage waveform across the element were measured to get the voltage-current characteristics. The allowable over-current and generated voltage were successfully estimated for the pure YBCO films. It can be pointed out that the lower n-value trends to bring about the higher allowable over-current and the higher withstand voltage more than tens of volts. The YBCO film having higher n-value is sensitive to the over-current. Thus, some protective methods such as a metal coating should be employed for applying to the fault current limiter.

48 CFR 908.7116 - Electronic data processing tape.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Electronic data processing... Electronic data processing tape. (a) Acquisitions of electronic data processing tape by DOE offices shall be in accordance with FPMR 41 CFR 101-26.508. (b) Acquisitions of electronic data processing tape by...

48 CFR 908.7116 - Electronic data processing tape.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Electronic data processing... Electronic data processing tape. (a) Acquisitions of electronic data processing tape by DOE offices shall be in accordance with FPMR 41 CFR 101-26.508. (b) Acquisitions of electronic data processing tape by...

48 CFR 908.7116 - Electronic data processing tape.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Electronic data processing... Electronic data processing tape. (a) Acquisitions of electronic data processing tape by DOE offices shall be in accordance with FPMR 41 CFR 101-26.508. (b) Acquisitions of electronic data processing tape by...

48 CFR 908.7116 - Electronic data processing tape.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Electronic data processing... Electronic data processing tape. (a) Acquisitions of electronic data processing tape by DOE offices shall be in accordance with FPMR 41 CFR 101-26.508. (b) Acquisitions of electronic data processing tape by...

48 CFR 908.7116 - Electronic data processing tape.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Electronic data processing... Electronic data processing tape. (a) Acquisitions of electronic data processing tape by DOE offices shall be in accordance with FPMR 41 CFR 101-26.508. (b) Acquisitions of electronic data processing tape by...

Microwave-assisted synthesis and critical analysis for YBa2Cu3O6+δ nanoparticles

NASA Astrophysics Data System (ADS)

Chhaganlal Gandhi, Ashish; Lin, Jauyn Grace

2018-05-01

A new cost effective scheme of a microwave-assisted sol–gel route followed by a short annealing time is proposed to synthesize YBCO nanoparticles (NPs) of various sizes. The advanced techniques of synchrotron radiation x-ray diffraction (SRXRD) and electron spin resonance (ESR) are used to analyze the size effects on their magnetic/superconducting properties. The major interesting finding is that the size of YBCO NPs could confine the amount of oxygen content and consequently change the superconducting transition temperature (T C ) of YBCO NPs. The ESR result demonstrates a sensitive probe to characterize surface defects in the oxygen-deficient YBCO NPs.

Study of Running Stability in Side-Suspended HTS-PMG Maglev Circular Line System

NASA Astrophysics Data System (ADS)

Zhou, Dajin; Zhao, Lifeng; Li, Linbo; Cui, Chenyu; Hsieh, Chang-Chun; Zhang, Yong; Guo, Jianqiang; Zhao, Yong

2017-07-01

A research on stability of the side-suspended HTS-PMG maglev circular line system is carried out through simulation experiment. The results show that the maglev vehicle will gradually get close to the track surface during acceleration under the action of centrifugal force, leading to decay of guidance force and occurrence of vertical eccentric motion. In case of linear array of YBa2Cu3O7-x (YBCO) bulks, the guidance force will be changed with the decreasing of the levitation gap. It can be suppressed through the complex arrangement of YBCO bulks. Fortunately, triangle array of YBCO bulks can effectively keep the guidance force constant and realize stable running during accelerating process of the prototype vehicle. Based on the research on stability of side-suspended maglev vehicle, a side-suspended PMG circular test track with diameter of 6.5 m and circumference of 20.4 m is successfully designed and established, enabling the prototype vehicle to run stably at up to 82.5 km/h under open atmosphere (9.6 × 104 Pa).

Fiber optic quench detection via optimized Rayleigh Scattering in high-field YBCO accelerator magnets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flanagan, Gene

Yttrium barium copper oxide (YBCO) coated conductors are known for their ability to operate in the superconducting state at relatively high temperatures, even above the boiling point of liquid nitrogen (77 K). When these same conductors are operated at lower temperatures, they are able to operate in much higher magnetic fields than traditional superconductors like NiTi or Nb 3Sn. Thus, YBCO superconducting magnets are one of the primary options for generating the high magnetic fields needed for future high energy physics devices. Due to slow quench propagation, quench detection remains one of the primary limitations to YBCO magnets. Fiber opticmore » sensing, based upon Rayleigh scattering, has the potential for spatial resolution approaching the wavelength of light, or very fast temporal resolution at low spatial resolution, and a continuum of combinations in between. This project has studied, theoretically and experimentally, YBCO magnets and Rayleigh scattering quench detection systems to demonstrate feasibility of the systems for YBCO quench protection systems. Under this grant an experimentally validated 3D quench propagation model was used to accurately define the acceptable range of spatial and temporal resolutions for effective quench detection in YBCO magnets and to evaluate present-day and potentially improved YBCO conductors. The data volume and speed requirements for quench detection via Rayleigh scattering required the development of a high performance fiber optic based quench detection/data acquisition system and its integration with an existing voltage tap/thermo-couple based system. In this project, optical fibers are tightly co-wound into YBCO magnet coils, with the fiber on top of the conductor as turn-to-turn insulation. Local changes in the temperature or strain of the conductor are sensed by the optical fiber, which is in close thermal and mechanical contact with the conductor. Intrinsic imperfections in the fiber reflect Rayleigh backscattered laser signals that are shifted by the changes in the fiber that are induced by a local change in the YBCO temperature or strain. One goal of this project was to show that modern technology can be used to interrogate the signals from a (very expensive) YBCO magnet to detect an impending quench in time to protect it from self-destruction. The results show that Rayleigh-backscattering interrogated optical fibers (RIOF) have significant advantages over traditional techniques, including very high spatial resolution and the ability to detect a hot-spot well before the peak local temperature becomes so high that the conductor can be damaged. RIOF quench detection is intrinsically faster than voltage taps, and this intrinsic advantage is greater as the coil size and/or current margin increases. We describe the development and testing program performed under the grant.« less

Growth rate of YBCO-Ag superconducting single grains

NASA Astrophysics Data System (ADS)

Congreve, J. V. J.; Shi, Y. H.; Dennis, A. R.; Durrell, J. H.; Cardwell, D. A.

2017-12-01

The large scale use of (RE)Ba2Cu3O7 bulk superconductors, where RE=Y, Gd, Sm, is, in part, limited by the relatively poor mechanical properties of these inherently brittle ceramic materials. It is reported that alloying of (RE)Ba2Cu3O7 with silver enables a significant improvement in the mechanical strength of bulk, single grain samples without any detrimental effect on their superconducting properties. However, due to the complexity and number of inter-related variables involved in the top seeded melt growth (TSMG) process, the growth of large single grains is difficult and the addition of silver makes it even more difficult to achieve successful growth reliably. The key processing variables in the TSMG process include the times and temperatures of the stages within the heating profile, which can be derived from the growth rate during the growth process. To date, the growth rate of the YBa2Cu3O7-Ag system has not been reported in detail and it is this lacuna that we have sought to address. In this work we measure the growth rate of the YBCO-Ag system using a method based on continuous cooling and isothermal holding (CCIH). We have determined the growth rate by measuring the side length of the crystallised region for a number of samples for specified isothermal hold temperatures and periods. This has enabled the growth rate to be modelled and from this an optimized heating profile for the successful growth of YBCO-Ag single grains to be derived.

Optimization of Thick, Large Area YBCO Film Growth Through Response Surface Methods

NASA Astrophysics Data System (ADS)

Porzio, J.; Mahoney, C. H.; Sullivan, M. C.

2014-03-01

We present our work on the optimization of thick, large area YB2C3O7-δ (YBCO) film growth through response surface methods. Thick, large area films have commercial uses and have recently been used in dramatic demonstrations of levitation and suspension. Our films are grown via pulsed laser deposition and we have optimized growth parameters via response surface methods. Response surface methods is a statistical tool to optimize selected quantities with respect to a set of variables. We optimized our YBCO films' critical temperatures, thicknesses, and structures with respect to three PLD growth parameters: deposition temperature, laser energy, and deposition pressure. We will present an overview of YBCO growth via pulsed laser deposition, the statistical theory behind response surface methods, and the application of response surface methods to pulsed laser deposition growth of YBCO. Results from the experiment will be presented in a discussion of the optimized film quality. Supported by NFS grant DMR-1305637

A Thermally Actuated Flux Pump for Energizing YBCO Pucks

DTIC Science & Technology

2016-05-01

transmitted through the thermal magnetic material sweeping magnetic field lines into the superconducting puck. We used YBCO as the superconductor with...of the YBCO sweeping vortices into the superconductor . These vortices would gradually accumulate in the superconductor . Successes have been reported...superconducting flux pump,” PHYSICA C, vol. 468, pp. 153-159, 2008. [2] T. A. Coombs, Z. Hong, Y. Yan and C. D. Rawlings, “ Superconductors : The

Critical current survival in the YBCO superconducting layer of a delaminated coated conductor

NASA Astrophysics Data System (ADS)

Feng, Feng; Fu, Qishu; Qu, Timing; Mu, Hui; Gu, Chen; Yue, Yubin; Wang, Linli; Yang, Zhirong; Han, Zhenghe; Feng, Pingfa

2018-04-01

A high-temperature superconducting coated conductor can be practically applied in electric equipment due to its favorable mechanical properties and critical current (I c) performance. However, the coated conductor can easily delaminate because of its poor stress tolerance along the thickness direction. It would be interesting to investigate whether the I c of the delaminated YBa2Cu3O7-δ (YBCO) layer can be preserved. In this study, coated conductor samples manufactured through the metal organic deposition route were delaminated by liquid nitrogen immersion. Delaminated samples, including the YBCO layer and silver stabilizer, were obtained. Delamination occurred inside the YBCO layer and near the YBCO-CeO2 interface, as suggested by the results of scanning electron microscopy (SEM) and x-ray diffraction. A scanning Hall probe system was employed to measure the I c distribution of the original sample and the delaminated sample. It was found that approximately 50% of the I c can be preserved after delamination, which was verified by I c measurements using the four-probe method. Dense and crack-free morphologies of the delaminated surfaces were observed by SEM, which accounts for the I c survival of the delaminated YBCO layer. The potential application of the delaminated sample in superconducting joints was discussed based on the oxygen diffusion estimation.

Design study of an YBCO-coated beam screen for the super proton-proton collider bending magnets

NASA Astrophysics Data System (ADS)

Gan, Pingping; Zhu, Kun; Fu, Qi; Li, Haipeng; Lu, Yuanrong; Easton, Matt; Liu, Yudong; Tang, Jingyu; Xu, Qingjin

2018-04-01

In order to reduce the beam impedance and refrigeration power dramatically, we have designed a high temperature superconductor (HTS) coated beam screen to screen the cold chamber walls of the super proton-proton collider bending magnets from beam-induced heat loads. It employs an absorber, inspired by the future circular collider studies, to absorb the immense synchrotron radiation power of 12.8 W/m emitted from the 37.5 TeV proton beams. Such a structure has the advantage of decreasing the electron cloud effect and improving the beam vacuum. We have compared the critical magnetic field and current density and accessibility of two potential HTS materials for the beam screen, TlBa2Ca2Cu3O9-δ (Tl-1223) and Yttrium Barium Copper Oxide (YBCO) and finally chose YBCO for coating. The beam screen is tentatively designed to work at 55-70 K because of the limited development of the YBCO material. The thermal analysis with oxygen cooling fluid indicates that the YBCO conductor can maintain its superconductivity even if the synchrotron radiation hits the YBCO-coated surface and the mechanical analysis shows that the structure has the ability to resist the Lorenz force during magnet quenches.

Inverse polarity of the resistive switching effect and strong inhomogeneity in nanoscale YBCO-metal contacts

NASA Astrophysics Data System (ADS)

Truchly, M.; Plecenik, T.; Zhitlukhina, E.; Belogolovskii, M.; Dvoranova, M.; Kus, P.; Plecenik, A.

2016-11-01

We have studied a bipolar resistive switching phenomenon in c-axis oriented normal-state YBa2Cu3O7-c (YBCO) thin films at room temperature by scanning spreading resistance microscopy (SSRM) and scanning tunneling microscopy (STM) techniques. The most striking experimental finding has been the opposite (in contrast to the previous room and low-temperature data for planar metal counter-electrode-YBCO bilayers) voltage-bias polarity of the switching effect in all SSRM and a number of STM measurements. We have assumed that the hysteretic phenomena in current-voltage characteristics of YBCO-based contacts can be explained by migration of oxygen-vacancy defects and, as a result, by the formation or dissolution of more or less conductive regions near the metal-YBCO interface. To support our interpretation of the macroscopic resistive switching phenomenon, a minimalist model that describes radical modifications of the oxygen-vacancy effective charge in terms of a charge-wind effect was proposed. It was shown theoretically that due to the momentum exchange between current carriers (holes in the YBCO compound) and activated oxygen ions, the direction in which oxygen vacancies are moving is defined by the balance between the direct electrostatic force on them and that caused by the current-carrier flow.

AC application of second generation HTS wire

NASA Astrophysics Data System (ADS)

Thieme, C. L. H.; Gagnon, K.; Voccio, J.; Aized, D.; Claassen, J.

2008-02-01

For the production of Second Generation (2G) YBCO High Temperature Superconductor wire American Superconductor uses a wide-strip MOD-YBCO/RABiTSTM process, a low-cost approach for commercial manufacturing. It can be engineered with a high degree of flexibility to manufacture practical 2G conductors with architectures and properties tailored for specific applications and operating conditions. For ac applications conductor and coil design can be geared towards low hysteretic losses. For applications which experience high frequency ac fields, the stabilizer needs to be adjusted for low eddy current losses. For these applications a stainless-steel laminate is used. An example is a Low Pass Filter Inductor which was developed and built in this work.

Growth of biaxially textured template layers using ion beam assisted deposition

NASA Astrophysics Data System (ADS)

Park, Seh-Jin

A two-step IBAD (ion beam assisted deposition) method is investigated, and compared to the conventional IBAD methods. The two step method uses surface energy anisotropy to achieve uniaxial texture and ion beam irradiation for biaxial texture. The biaxial texture was achieved by selective surface etching and enhanced by grain overgrowth. In this method, biaxial texture alignment is performed on a (001) uniaxially textured buffer layer. The material selected for achieving uniaxial texture, YBCO (YBa2Cu3O7-x), has strong surface energy anisotropy. YBCO is chemically susceptible to the reaction with the adjacent layer. Yttria stabilized zirconia (YSZ) was used to prevent the reaction between YBCO and the substrates (polycrystalline Ni alloy [Hastelloy] and amorphous SiNx/Si). A SrTiO3 layer was deposited on the uniaxially textured YBCO layer to retard stoichiometry change with subsequent processing. STO is well lattice matched with YBCO. A top layer of Ni was then deposited. The Ni layer was used for studying the effect of grain overgrowth. The obtained uniaxial Ni films were used for subsequent ion beam processing. Ar ion beam irradiation onto the uniaxially textured Ni film was used to study the effect of selective grain etching in achieving in-plane aligned Ni grains. Additional Ni deposition induces the overgrowth of the in-plane aligned Ni grains and, finally, the overall in-plane alignment. The in-plane alignment is examined with XRD phi scan. The effect of surface polarity of insulating oxide substrates on the epitaxial growth behavior was investigated. The lattice strain energy was the most important factor for determining the orientation of Ni films on a non-polar surface. However, for a polar surface, the surface energy plays an important role in determining the final orientation of the Ni films based on the experimental and theoretical results. Y2O3 growth behavior was also studied. The lattice strain energy is the most important factor for Y2O3 growth on single crystalline substrates. The surface energy anisotropy is the most important factor for the growth on amorphous substrates. The XRD phi scan study shows that Ar ion beam irradiation with favorable angle of incidence enhances the in-plane alignment of Y2O3 films grown on randomly oriented substrates due to the ion channeling.

Trapped Field Characteristics of Stacked YBCO Thin Plates for Compact NMR Magnets: Spatial Field Distribution and Temporal Stability

PubMed Central

Hahn, Seungyong; Kim, Seok Beom; Ahn, Min Cheol; Voccio, John; Bascuñán, Juan; Iwasa, Yukikazu

2010-01-01

This paper presents experimental and analytical results of trapped field characteristics of a stack of square YBCO thin film plates for compact NMR magnets. Each YBCO plate, 40 mm × 40 mm × 0.08 mm, has a 25-mm diameter hole at its center. A total of 500 stacked plates were used to build a 40-mm long magnet. Its trapped field, in a bath of liquid nitrogen, was measured for spatial field distribution and temporal stability. Comparison of measured and analytical results is presented: the effects on trapped field characteristics of the unsaturated nickel substrate and the non-uniform current distribution in the YBCO plate are discussed. PMID:20585463

OCLC-MARC Tape Processing: A Functional Analysis.

ERIC Educational Resources Information Center

Miller, Bruce Cummings

1984-01-01

Analyzes structure of, and data in, the OCLC-MARC record in the form delivered via OCLC's Tape Subscription Service, and outlines important processing functions involved: "unreadable tapes," duplicate records and deduping, match processing, choice processing, locations processing, "automatic" and "input" stamps,…

Analysis of cache for streaming tape drive

NASA Technical Reports Server (NTRS)

Chinnaswamy, V.

1993-01-01

A tape subsystem consists of a controller and a tape drive. Tapes are used for backup, data interchange, and software distribution. The backup operation is addressed. During a backup operation, data is read from disk, processed in CPU, and then sent to tape. The processing speeds of a disk subsystem, CPU, and a tape subsystem are likely to be different. A powerful CPU can read data from a fast disk, process it, and supply the data to the tape subsystem at a faster rate than the tape subsystem can handle. On the other hand, a slow disk drive and a slow CPU may not be able to supply data fast enough to keep a tape drive busy all the time. The backup process may supply data to tape drive in bursts. Each burst may be followed by an idle period. Depending on the nature of the file distribution in the disk, the input stream to the tape subsystem may vary significantly during backup. To compensate for these differences and optimize the utilization of a tape subsystem, a cache or buffer is introduced in the tape controller. Most of the tape drives today are streaming tape drives. A streaming tape drive goes into reposition when there is no data from the controller. Once the drive goes into reposition, the controller can receive data, but it cannot supply data to the tape drive until the drive completes its reposition. A controller can also receive data from the host and send data to the tape drive at the same time. The relationship of cache size, host transfer rate, drive transfer rate, reposition, and ramp up times for optimal performance of the tape subsystem are investigated. Formulas developed will also show the advantages of cache watermarks to increase the streaming time of the tape drive, maximum loss due to insufficient cache, tradeoffs between cache and reposition times and the effectiveness of cache on a streaming tape drive due to idle times or interruptions due in host transfers. Several mathematical formulas are developed to predict the performance of the tape drive. Some examples are given illustrating the usefulness of these formulas. Finally, a summary and some conclusions are provided.

High T(sub c) Superconducting Bolometer on Chemically Etched 7 Micrometer Thick Sapphire

NASA Technical Reports Server (NTRS)

Lakew, B.; Brasunas, J. C.; Pique, A.; Fettig, R.; Mott, B.; Babu, S.; Cushman, G. M.

1997-01-01

A transition-edge IR detector, using a YBa2Cu3O(7-x) (YBCO) thin film deposited on a chemically etched, 7 micrometer thick sapphire substrate has been built. To our knowledge it is the first such high T(sub c) superconducting (HTS) bolometer on chemically thinned sapphire. The peak optical detectivity obtained is l.2 x 10(exp 10) cmHz(sup 1/2)/W near 4Hz. Result shows that it is possible to obtain high detectivity with thin films on etched sapphire with no processing after the deposition of the YBCO film. We discuss the etching process and its potential for micro-machining sapphire and fabricating 2-dimensional detector arrays with suspended sapphire membranes. A 30 micrometer thick layer of gold black provided IR absorption. Comparison is made with the current state of the art on silicon substrates.

YBa2Cu3O7 thin films on nanocrystalline diamond films for HTSC bolometer

NASA Technical Reports Server (NTRS)

Cui, G.; Beetz, C. P., Jr.; Boerstler, R.; Steinbeck, J.

1993-01-01

Superconducting YBa2Cu3O(7-x) films on nanocrystalline diamond thin films have been fabricated. A composite buffer layer system consisting of diamond/Si3N4/YSZ/YBCO was explored for this purpose. The as-deposited YBCO films were superconducting with Tc of about 84 K and a relatively narrow transition width of about 8 K. SEM cross sections of the films showed very sharp interfaces between diamond/Si3N4 and between Si3N4/YSZ. The deposited YBCO film had a surface roughness of about 1000 A, which is suitable for high-temperature superconductive (HTSC) bolometer fabrication. It was also found that preannealing of the nanocrystalline diamond thin films at high temperature was very important for obtaining high-quality YBCO films.

Buffer layers for high-Tc thin films on sapphire

NASA Technical Reports Server (NTRS)

Wu, X. D.; Foltyn, S. R.; Muenchausen, R. E.; Cooke, D. W.; Pique, A.; Kalokitis, D.; Pendrick, V.; Belohoubek, E.

1992-01-01

Buffer layers of various oxides including CeO2 and yttrium-stabilized zirconia (YSZ) have been deposited on R-plane sapphire. The orientation and crystallinity of the layers were optimized to promote epitaxial growth of YBa2Cu3O(7-delta) (YBCO) thin films. An ion beam channeling minimum yield of about 3 percent was obtained in the CeO2 layer on sapphire, indicating excellent crystallinity of the buffer layer. Among the buffer materials used, CeO2 was found to be the best one for YBCO thin films on R-plane sapphire. High Tc and Jc were obtained in YBCO thin films on sapphire with buffer layers. Surface resistances of the YBCO films were about 4 mOmega at 77 K and 25 GHz.

Design and performance of a high-Tc superconductor coplanar waveguide filter

NASA Technical Reports Server (NTRS)

Chew, Wilbert; Riley, A. L.; Rascoe, Daniel L.; Hunt, Brian D.; Foote, Marc C.; Cooley, Thomas W.; Bajuk, Louis J.

1991-01-01

The design of a coplanar waveguide low-pass filter made of YBa2Cu3O(7-delta) (YBCO) on an LaAlO3 substrate is described. Measurements were incorporated into simple models for microwave CAD analysis to develop a final design. The patterned and packaged coplanar waveguide low-pass filter of YBCO, with dimensions suited for integrated circuits, exhibited measured insertion losses when cooled in liquid nitrogen superior to those of a similarly cooled thin-film copper filter throughout the 0 to 9.5 GHz passband. Coplanar waveguide models for use with thin-film normal metal (with thickness either greater or less than the skin depth) and YBCO are discussed and used to compare the losses of the measured YBCO and copper circuits.

User's guide to the UTIL-ODRC tape processing program. [for the Orbital Data Reduction Center

NASA Technical Reports Server (NTRS)

Juba, S. M. (Principal Investigator)

1981-01-01

The UTIL-ODRC computer compatible tape processing program, its input/output requirements, and its interface with the EXEC 8 operating system are described. It is a multipurpose orbital data reduction center (ODRC) tape processing program enabling the user to create either exact duplicate tapes and/or tapes in SINDA/HISTRY format. Input data elements for PRAMPT/FLOPLT and/or BATCH PLOT programs, a temperature summary, and a printed summary can also be produced.

A comparison of superconductor and manganin technology for electronic links used in space mission applications

NASA Technical Reports Server (NTRS)

Caton, R.; Selim, R.; Buoncristiani, A. M.

1992-01-01

The electronic link connecting cryogenically cooled radiation detectors to data acquisition and signal processing electronics at higher temperatures contributes significantly to the total heat load on spacecraft cooling systems that use combined mechanical and cryogenic liquid cooling. Using high transition temperature superconductors for this link has been proposed to increase the lifetime of space missions. Herein, several YBCO (YBa2Cu3O7) superconductor-substrate combinations were examined and total heat loads were compared to manganin wire technology in current use. Using numerical solutions to the heat-flow equations, it is shown that replacing manganin technology with YBCO thick film technology can extend a 7-year mission by up to 1 year.

Specific Effects of Oxygen Molecule and Plasma on Thin-Film Growth of Y-Ba-Cu-O and Bi-Sr-(Ca)-Cu-O Systems

NASA Astrophysics Data System (ADS)

Endo, Tamio; Horie, Munehiro; Hirate, Naoki; Itoh, Katsutoshi; Yamada, Satoshi; Tada, Masaki; Itoh, Ken-ichi; Sugiyama, Morihiro; Sano, Shinji; Watabe, Kinji

1998-07-01

Thin films of a-oriented YBa2Cu3Ox (YBCO), Ca-doped c-oriented Bi2(Sr,Ca)2CuOx and nondoped c-oriented Bi2Sr2CuOx (Bi2201) were prepared at low temperatures by ion beam sputtering with supply of oxygen molecules or plasma. The plasma enhances crystal growth of the a-YBCO and Ca-doped Bi2201 phases. This can be interpreted in terms of their higher surface energies. The growth and quality of nondoped Bi2201 are improved with the supply of oxygen molecules. This particular result could be interpreted by the collision process between the oxygen molecules and the sputtered particles.

Investigation for surface resistance of yttrium-barium-copper-oxide thin films on various substrates for microwave applications

NASA Astrophysics Data System (ADS)

Yao, Hongjun

High temperature superconducting (HTS) materials such as YBCO (Yttrium-Barium-Copper-Oxide) are very attractive in microwave applications because of their extremely low surface resistance. In the proposed all-HTS tunable filter, a layer of HTS thin film on a very thin substrate (100 mum) is needed to act as the toractor that can be rotated to tune the frequency. In order to provide more substrate candidates that meet both electrical and mechanical requirements for this special application, surface resistance of YBCO thin films on various substrates was measured using microstrip ring resonator method. For alumina polycrystalline substrate, a layer of YSZ (Yttrium stabilized Zirconia) was deposited using IBAD (ion beam assisted deposition) method prior to YBCO deposition. The surface resistance of the YBCO thin film on alumina was found to be 22 mO due to high-angle grain boundary problem caused by the mixed in-plane orientations and large FWHM (full width at half maximum) of the thin film. For YBCO thin films on a YSZ single crystal substrate, the surface resistance showed even higher value of 30 mO because of the mixed in-plane orientation problem. However, by annealing the substrate in 200 Torr oxygen at 730°C prior to deposition, the in-plane orientation of YBCO thin films can be greatly improved. Therefore, the surface resistance decreased to 1.4 mO, which is still more than an order higher than the reported best value. The YBCO thin films grown on LaAlO3 single crystal substrate showed perfect in-plane orientation with FWHM less 1°. The surface resistance was as low as 0.032 mO. A tunable spiral resonator made of YBCO thin film on LaAlO3 single crystal substrate demonstrated that the resonant frequency can be tuned in a rang as large as 500 MHz by changing the gap between toractor and substrate. The Q-factor was more than 12,000, which ensured the extraordinarily high sensitivity for the proposed all-HTS tunable filter.

Low-Flammability PTFE for High-Oxygen Environments

NASA Technical Reports Server (NTRS)

Walle, E.; Fallon, B.; Sheppard, A.

1986-01-01

Modified forming process removes volatile combustible materials. Flammability of cable-wrapping tape reduced by altering tape-manufacturing process. In new manufacturing process, tape formed by proprietary process of screw extrusion, followed by washing in solvent and drying. Tape then wrapped as before. Spectrogram taken after extrusion, washing, and drying shows lower hydrocarbon content. PTFE formed by new process suited to oxygen-rich environments. Safe in liquid oxygen of Space Shuttle tank and in medical uses; thin-wall shrinkable tubing in hospital test equipment, surgical instruments, and implants.

The effect of temperature cycling typical of low earth orbit satellites on thin films of YBa2Cu3O(7-x)

NASA Technical Reports Server (NTRS)

Mogro-Campero, A.; Turner, L. G.; Bogorad, A.; Herschitz, R.

1991-01-01

Thin films of YBa2Cu3O(7-x) (YBCO) were temperature cycled to simulate conditions of a low earth orbit satellite. In one series of tests, epitaxial and polycrystalline YBCO films were cycled between temperatures of +/- 80 C in vacuum and in nitrogen for hundreds of cycles. The room temperature resistance of an epitaxial YBCO film increased by about 10 percent, but the superconducting transition temperature was unchanged. The largest changes were for a polycrystalline YBCO film on oxidized silicon with a zirconia buffer layer, for which the transition temperature decreased by 3 K. An extended test was carried out for epitaxial films. After 3200 cycles (corresponding to about 230 days in space), transition temperatures and critical current densities remained unchanged.

Direct observation of twin deformation in YBa2Cu3O7-x thin films by in situ nanoindentation in TEM

NASA Astrophysics Data System (ADS)

Lee, Joon Hwan; Zhang, Xinghang; Wang, Haiyan

2011-04-01

The deformation behaviors of YBa2Cu3O7-x (YBCO) thin films with twinning structures were studied via in situ nanoindentation experiments in a transmission electron microscope. The YBCO films were grown on SrTiO3 (001) substrates by pulsed laser deposition. Both ex situ (conventional) and in situ nanoindentation were conducted to reveal the deformation of the YBCO films from the directions perpendicular and parallel to the twin interfaces. The hardness measured perpendicular to the twin interfaces is ˜50% and 40% higher than that measured parallel to the twin interfaces ex situ and in situ, respectively. Detailed in situ movie analysis reveals that the twin structures play an important role in deformation and strengthening mechanisms in YBCO thin films.

Solution-Based Approaches to Fabrication of YBa2Cu3O7-δ (YBCO): Precursors of Tri-Fluoroacetate (TFA) and Nanoparticle Colloids

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S. M.; Su, J.; Chintamaneni, V.

2007-10-01

Detailed investigation of superconducting films of YBa2Cu3O7-δ (YBCO) prepared from solution-based precursors have been performed. Two precursors have been compared in this study: the presently used trifluoroacetate (TFA) solution and a recently developed colloidal suspension containing nanoparticles of mixed oxide. Detailed analyses of the evolution of microstructure and chemistry of the films have been performed, and process parameters have been correlated with final superconducting properties. Both films need two heating steps: a low temperature calcination and a higher temperature crystallization step. For TFA films, it was seen that the heating rate during calcination needs to be carefully optimized and is expected to be slow. For the alternate process using a nanoparticle precursor, a significantly faster calcination rate is possible. In the TFA process, the Ba ion remains as fluoride and the Y remains as oxyfluoride after calcination. This implies that, during the final crystallization stage to form YBCO, fluorine-containing gases will evolve, resulting in residual porosity. On the other hand, the film from the nanoparticle process is almost fully oxidized after calcination. Therefore, no gases evolve at the final firing (crystallization) stage, and the film has much lower porosity. The superconducting properties of both types of films are adequate, but the nanoparticle films appear to have persistently higher J c values. Moreover, they show improved flux pinning in higher magnetic fields, probably due to nanoscale precipitates of a Cu-rich phase. In addition, the nanocolloid films seem to show additionally enhanced flux pinning when doped with minute amounts of second phase precipitates. It therefore appears that, whereas the TFA process is already quite successful, the newly developed nanoparticle process has significant scope for additional improvement. It can be scaled-up with ease, and can be easily adapted to incorporate nanoscale flux pinning defects for in-field performance.

COMPUTER DATA PROCESSING SYSTEM. PROJECT ROVER, 1962

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narin, F.

ABS>A system was created for processing large volumes of data from Project ROVER tests at the Nevada Test Site. The data are compiled as analog, frequency modulated tape, which is translated in a Packard-Bell Tape-to-Tape converter into a binary coded decimal (BCD) IBM 7090 computer input tape. This input tape, tape A5, is processed on the 7090 by the RDH-D FORTRAN-II code and its 20 FAP and FORTRAN subroutines. Outputs from the 7090 run are tapes A3, which is a BCD tape used for listing on the IBM 1401 input-output computer, tape B5 which is a binary tape used asmore » input to a Stromberg-Carlson 40/20 cathode ray tube (CRT) plotter, and tape B6 which is a binary tape used for permanent data storage and input to specialized subcodes. The information on tape B5 commands the 40/20 to write grids, data points, and other information on the face of a CRT; the information on the CRT is photographed on 35 mm film which is subsequently developed; full-size (10" x 10") plots are made from the 35 mm film on a Xerox 1824 printer. The 7090 processes a data channel in approximately 4 seconds plus 4 seconds per plot to be made on the 40/20 for that channel. Up to 4500 data and calibration points on any one channel may be processed in one pass of the RDH-D code. This system has been used to produce more than 100,000 prints on the 1824 printer from more than 10,000 different 40/20 plots. At 00 per minute of 7090 time, it costs 60 to process a typical, 3-plot data channel on the 7090; each print on the 1824 costs between 5 and 10 cents including rental, supplies, and operator time. All automatic computer stops in the codes and subroutines are accompanied by on-line instructions to the operator. Extensive redundancy checking is incorporated in the FAP tape handling subroutines. (auth)« less

Effects of graphene oxide doping on the structural and superconducting properties of YBa2Cu3O7-δ

NASA Astrophysics Data System (ADS)

Dadras, S.; Falahati, S.; Dehghani, S.

2018-05-01

In this research we reported the effects of graphene oxide (GO) doping on the structural and superconducting properties of YBa2Cu3O7-δ (YBCO) high temperature superconductors. We synthesized YBCO powder by sol-gel method. After calcination, the powder mixed with different weight percent (0, 0.1, 0.3, 0.7, 1 wt.%) of GO. Refinement of X-ray diffraction (XRD) was carried out by material analysis using diffraction (MAUD) program to obtain the structural parameters such as lattice parameters, site occupancy of different atoms and orthorhombicity value for the all samples. Results show that GO doping does not change the structure of YBCO compound, Cu (1), Cu (2) and oxygen sites occupancy. It seems that GO remains between the grains and can play the role of weak links. We found that GO addition to YBCO compound increases transition temperature (TC). The oxygen contents of the all GO-doped samples are increased with respect to the pure one. The strain (ɛ) of the samples obtained from Williamson-Hall method, varies with increasing of GO doping. The scanning electron microscopy (SEM) images of the samples show better YBCO grain connections by GO doping.

Ultrasonic studies of high-temperature superconductors

NASA Astrophysics Data System (ADS)

Feller, Jeffrey Robert

1997-09-01

This dissertation consists roughly of two parts. The first part deals with YBa2Cu3O7-δ (YBCO) films deposited on piezoelectric (LiNbO3) substrates. Interdigital surface acoustic wave (SAW) devices (delay lines operating at center frequencies of 50 and 100 MHz) fabricated from YBCO films are examined; insertion loss measurements are presented, and electrode resistance effects are analyzed using equivalent circuit models. Sheet resistance and 168 MHz SAW attenuation measurements of a granular YBCO film on LiNbO3 are also presented. The experimental data are discussed in terms of a percolation theory that models the film as an array of identical YBCO grains connected by resistive junctions which, in the superconducting state behave as Josephson junctions. The normal state resistances of the junctions are assumed to be randomly distributed. In the second part of the dissertation, a number of novel techniques (SAW 'bridges,' the high frequency interdigital proximity probe, and weak acoustic coupling sampled continuous wave spectrometry), used in the study of the vortex state and structural transitions in the normal state of YBCO films and single crystals, are described. Evidence of the existence of a first order structural transition in the vicinity of 220 K is provided.

Multi-Response Parameter Interval Sensitivity and Optimization for the Composite Tape Winding Process.

PubMed

Deng, Bo; Shi, Yaoyao; Yu, Tao; Kang, Chao; Zhao, Pan

2018-01-31

The composite tape winding process, which utilizes a tape winding machine and prepreg tapes, provides a promising way to improve the quality of composite products. Nevertheless, the process parameters of composite tape winding have crucial effects on the tensile strength and void content, which are closely related to the performances of the winding products. In this article, two different object values of winding products, including mechanical performance (tensile strength) and a physical property (void content), were respectively calculated. Thereafter, the paper presents an integrated methodology by combining multi-parameter relative sensitivity analysis and single-parameter sensitivity analysis to obtain the optimal intervals of the composite tape winding process. First, the global multi-parameter sensitivity analysis method was applied to investigate the sensitivity of each parameter in the tape winding processing. Then, the local single-parameter sensitivity analysis method was employed to calculate the sensitivity of a single parameter within the corresponding range. Finally, the stability and instability ranges of each parameter were distinguished. Meanwhile, the authors optimized the process parameter ranges and provided comprehensive optimized intervals of the winding parameters. The verification test validated that the optimized intervals of the process parameters were reliable and stable for winding products manufacturing.

Multi-Response Parameter Interval Sensitivity and Optimization for the Composite Tape Winding Process

PubMed Central

Yu, Tao; Kang, Chao; Zhao, Pan

2018-01-01

The composite tape winding process, which utilizes a tape winding machine and prepreg tapes, provides a promising way to improve the quality of composite products. Nevertheless, the process parameters of composite tape winding have crucial effects on the tensile strength and void content, which are closely related to the performances of the winding products. In this article, two different object values of winding products, including mechanical performance (tensile strength) and a physical property (void content), were respectively calculated. Thereafter, the paper presents an integrated methodology by combining multi-parameter relative sensitivity analysis and single-parameter sensitivity analysis to obtain the optimal intervals of the composite tape winding process. First, the global multi-parameter sensitivity analysis method was applied to investigate the sensitivity of each parameter in the tape winding processing. Then, the local single-parameter sensitivity analysis method was employed to calculate the sensitivity of a single parameter within the corresponding range. Finally, the stability and instability ranges of each parameter were distinguished. Meanwhile, the authors optimized the process parameter ranges and provided comprehensive optimized intervals of the winding parameters. The verification test validated that the optimized intervals of the process parameters were reliable and stable for winding products manufacturing. PMID:29385048

Simulation and analysis of tape spring for deployed space structures

NASA Astrophysics Data System (ADS)

Chang, Wei; Cao, DongJing; Lian, MinLong

2018-03-01

The tape spring belongs to the configuration of ringent cylinder shell, and the mechanical properties of the structure are significantly affected by the change of geometrical parameters. There are few studies on the influence of geometrical parameters on the mechanical properties of the tape spring. The bending process of the single tape spring was simulated based on simulation software. The variations of critical moment, unfolding moment, and maximum strain energy in the bending process were investigated, and the effects of different radius angles of section and thickness and length on driving capability of the simple tape spring was studied by using these parameters. Results show that the driving capability and resisting disturbance capacity grow with the increase of radius angle of section in the bending process of the single tape spring. On the other hand, these capabilities decrease with increasing length of the single tape spring. In the end, the driving capability and resisting disturbance capacity grow with the increase of thickness in the bending process of the single tape spring. The research has a certain reference value for improving the kinematic accuracy and reliability of deployable structures.

BaHfO3 artificial pinning centres in TFA-MOD-derived YBCO and GdBCO thin films

NASA Astrophysics Data System (ADS)

Erbe, M.; Hänisch, J.; Hühne, R.; Freudenberg, T.; Kirchner, A.; Molina-Luna, L.; Damm, C.; Van Tendeloo, G.; Kaskel, S.; Schultz, L.; Holzapfel, B.

2015-11-01

Chemical solution deposition (CSD) is a promising way to realize REBa2Cu3O7-x (REBCO; RE = rare earth (here Y, Gd))-coated conductors with high performance in applied magnetic fields. However, the preparation process contains numerous parameters which need to be tuned to achieve high-quality films. Therefore, we investigated the growth of REBCO thin films containing nanometre-scale BaHfO3 (BHO) particles as pinning centres for magnetic flux lines, with emphasis on the influence of crystallization temperature and substrate on the microstructure and superconductivity. Conductivity, microscopy and x-ray investigations show an enhanced performance of BHO nano-composites in comparison to pristine REBCO. Further, those measurements reveal the superiority of GdBCO to YBCO—e.g. by inductive critical current densities, J c, at self-field and 77 K. YBCO is outperformed by more than 1 MA cm-2 with J c values of up to 5.0 MA cm-2 for 265 nm thick layers of GdBCO(BHO) on lanthanum aluminate. Transport in-field J c measurements demonstrate high pinning force maxima of around 4 GN m-3 for YBCO(BHO) and GdBCO(BHO). However, the irreversibility fields are appreciably higher for GdBCO. The critical temperature was not significantly reduced upon BHO addition to both YBCO and GdBCO, indicating a low tendency for Hf diffusion into the REBCO matrix. Angular-dependent J c measurements show a reduction of the anisotropy in the same order of magnitude for both REBCO compounds. Theoretical models suggest that more than one sort of pinning centre is active in all CSD films.

Fabrication of Polyimide-Matrix/Carbon and Boron-Fiber Tape

NASA Technical Reports Server (NTRS)

Belvin, Harry L.; Cano, Roberto J.; Treasure, Monte; Shahood, Thomas W.

2007-01-01

The term HYCARB denotes a hybrid composite of polyimide matrices reinforced with carbon and boron fibers. HYCARB and an improved process for fabricating dry HYCARB tapes have been invented in a continuing effort to develop lightweight, strong composite materials for aerospace vehicles. Like other composite tapes in this line of development, HYCARB tapes are intended to be used to build up laminated structures having possibly complex shapes by means of automated tow placement (ATP) - a process in which a computer-controlled multiaxis machine lays down prepreg tape or tows. The special significance of the present process for making dry HYCARB for ATP is that it contributes to the reduction of the overall cost of manufacturing boron-reinforced composite-material structures while making it possible to realize increased compression strengths. The present process for making HYCARB tapes incorporates a "wet to dry" process developed previously at Langley Research Center. In the "wet to dry" process, a flattened bundle of carbon fiber tows, pulled along a continuous production line between pairs of rollers, is impregnated with a solution of a poly(amide acid) in N-methyl-2-pyrrolidinone (NMP), then most of the NMP is removed by evaporation in hot air. In the present case, the polyamide acid is, more specifically, that of LaRC. IAX (or equivalent) thermoplastic polyimide, and the fibers are, more specifically, Manganite IM7 (or equivalent) polyacrylonitrile- based carbon filaments that have a diameter of 5.2 m and are supplied in 12,000-filament tows. The present process stands in contrast to a prior process in which HYCARB tape was made by pressing boron fibers into the face of a wet carbon-fiber/ poly(amide acid) prepreg tape . that is, a prepreg tape from which the NMP solvent had not been removed. In the present process, one or more layer(s) of side-by-side boron fibers are pressed between dry prepreg tapes that have been prepared by the aforementioned gwet to dry h process. The multilayer tape is then heated to imidize the matrix material and remove most of the remaining solvent, and is pressed to consolidate the multiple layers into a dense tape. For tests, specimens of HYCARB tapes and laminated composite panels made from HYCARB tape were prepared as follows: HYCARB tapes were fabricated as described above. Each panel was made by laying down ten layers of tape, containing, variously, one, two, or three boron-fiber plies and the remainder carbon- fiber-only plies (see figure). Each panel was made by laying down ten layers of tape. Each panel was then cured by heating to a temperature of 225 C for 15 minutes, then pressing at 200 psi (A1.4 MPa) while heating to 371 C, holding at 371 C for 1 hour, then continuing to hold pressure during cooling. Control specimens that were otherwise identical except that they did not contain boron fibers also were prepared. In room-temperature flexural tests, the HYCARB specimens performed comparably to the control specimens; in room-temperature, open-hole compression tests, the HYCARB specimens performed slightly better, by amounts that increased with boron content.

41 CFR 101-26.508-2 - Requisitioning data processing tape not available from Federal Supply Schedule contracts.

Code of Federal Regulations, 2013 CFR

2013-07-01

... contracts. (a) Requisitions for types of EDP tape and instrumentation tape (wide and intermediate band... is located. (b) Requisitions for all types of EDP tape and instrumentation tape (wide and... and $5,000 for instrumentation tape. However, regardless of the amount involved (including...

Flux pinning in yttrium barium copper oxide coated conductors

NASA Astrophysics Data System (ADS)

Chen, Zhijun

High quality high-temperature-superconducting YBa2Cu 3O7-x (YBCO) films for industrial applications demand very high critical current densities Jc, which can only be achieved by strong three-dimensional (3D) pinning with deliberately introduced nano-precipitates. The purpose of this thesis is to provide an in-depth understanding of the 3D pinning in such YBCO films. In pulsed laser deposition (PLD) prepared YBCO films, a high density of anti-phase boundaries and stacking faults were found to be effective pinning defects for improving Jc in small fields. However, their failure to improve Jc at high fields shows that such naturally generated defects are not strong 3D pinning centers. A demonstration of strong 3D pinning was found in a metal organic chemical vapor deposition (MOCVD) grown YBCO coated conductor (CC) with a high density of (Y,Sm)2O3 nano-precipitates. We observed a significantly enhanced irreversibility field Hirr which, like other superconducting properties was independent of thickness, due to strong vortex-pin interactions. The advantage of 3D pinning was further illustrated by a bi-layer metalorganic deposition (MOD) grown YBCO CC with different 3D pinning structures in each layer. The Jc anisotropy of the bilayer was found to be the thickness-weighted sum of the anisotropy of the two individual layers, demonstrating an applicable way to tune the Jcanisotropy. Moreover, extensive low temperature and high magnetic field evaluations performed on an MOCVD CC with dense 3D (Y,Sm) 2O3 nano-precipitate pinning centers showed that its strong vortex pinning at 77 K correlated well to strong performance at 4.2 K too. YBCO films with quantitatively controlled artificial Y2O 3 nano-precipitates were also grown by PLD, and characterized over wide temperature and field ranges. Their Jc was found to be determined by the vortex pinning mediated by thermal fluctuation effects. In weak thermal-fluctuation situations Jc increased with decreasing effective precipitate spacing Lc. In other situations, Jc depends on both Lc and the size and elementary pinning strength of the nano-precipitates. In summary, this thesis presents detailed pinning studies on several differently grown YBCO films. Our results identify the optimum pinning structures in YBCO films and provide a systematic guidance for optimizing vortex pinning.

Dry Process for Manufacturing Hybridized Boron Fiber/Carbon Fiber Thermoplastic Composite Materials from a Solution Coated Precursor

NASA Technical Reports Server (NTRS)

Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor)

2003-01-01

An apparatus for producing a hybrid boron reinforced polymer matrix composite from precursor tape and a linear array of boron fibers. The boron fibers are applied onto the precursor tapes and the precursor tape processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the precursor tape with the boron fibers becomes a hybrid boron reinforced polymer matrix composite. A driving mechanism is used to pulled the precursor tape through the method and a take-up spool is used to collect the formed hybrid boron reinforced polymer matrix composite.

Effects of densification of precursor pellets on microstructures and critical current properties of YBCO melt-textured bulks

NASA Astrophysics Data System (ADS)

Setoyama, Yui; Shimoyama, Jun-ichi; Motoki, Takanori; Kishio, Kohji; Awaji, Satoshi; Kon, Koichi; Ichikawa, Naoki; Inamori, Satoshi; Naito, Kyogo

2016-12-01

Effects of densification of precursor disks on the density of residual voids and critical current properties for YBCO melt-textured bulk superconductors were systematically investigated. Six YBCO bulks were prepared from precursor pellets with different initial particle sizes of YBa2Cu3Oy (Y123) powder and applied pressures for pelletization. It was revealed that use of finer Y123 powder and consolidation using cold-isostatic-pressing (CIP) with higher pressures result in reduction of residual voids at inner regions of bulks and enhance Jc especially under low fields below the second peak.

A new RE + 011 TSIG method for the fabrication of high quality and large size single domain YBCO bulk superconductors

NASA Astrophysics Data System (ADS)

Yang, W. M.; Chen, L. P.; Wang, X. J.

2016-02-01

High quality single domain YBCO bulk superconductors, 20 mm in diameter, have been fabricated using a new top seeded infiltration and growth method (called the RE + 011 TSIG method), with a new solid phase (Y2O3 + xBaCuO2) instead of the conventional Y2BaCuO5 solid phase, x = 0, 0.5, 1.0, 1.2, 1.5, 1.8, 2.0, 2.5, 3.0. The effects of different BaCuO2 contents x on the growth morphology, microstructure, and levitation force have been investigated. The results show that the levitation force of the YBCO bulks first increases and then decreases with increasing x, and reaches maximum levitation forces of about 49.2 N (77 K, 0.5 T, with the traditional liquid phase of YBa2Cu3O y + 3 BaCuO2 + 2 CuO) and 47 N (77.3 K, 0.5 T, with the new liquid phase of Y2O3 + 10 BaCuO2 + 6 CuO) when x = 1.2, which is much higher than that of the samples fabricated with the conventional solid phases (23 N). The average Y2BaCuO5 particle size is about 1 μm, which is much smaller than the 3.4 μm in the samples prepared with the conventional Y2BaCuO5 solid phase; this means that the flux pinning force of the sample can be improved by using the new solid phase. Based on this method, single domain YBCO bulks 40 mm, 59 mm, and 93 mm in diameter have also been fabricated using the TSIG process with the new solid phases (Y2O3 + 1.2BaCuO2). These results indicate that the new TSIG process developed by our lab is a very important and practical method for the fabrication of low cost, large size, and high quality single domain REBCO bulk superconductors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, L.M.

Presently some methods of HTS-conductors processing are under study in the authors laboratory. ``Powder-in-tube`` (PIT), ``Jelly-roll``, electrophorethis are among them. PIT process has developed predominantly both in a view of the achieved J{sub c} values Bi-2223 phase was used as a core material for these tapes. Since the main purpose of the task order was to enhance the development of long length high temperature superconductor tapes, the authors have considered reasonable to lay the perfection idea of the PIT process step by step or tape by tape. To realize it they have assumed, keeping stable the basic scheme of PITmore » process, to vary some technological parameters which are as follows: (1) type of initial powder; (2) sheath material; (3) tape construction (filaments number, cross section e.a.); and (4) processing regimes. This report covers the fabrication process and characteristics of the produced conductors.« less

Apparatus and method for loading and unloading multiple digital tape cassettes utilizing a removable magazine

DOEpatents

Lindenmeyer, C.W.

1993-01-26

An apparatus and method to automate the handling of multiple digital tape cassettes for processing by commercially available cassette tape readers and recorders. A removable magazine rack stores a plurality of tape cassettes, and cooperates with a shuttle device that automatically inserts and removes cassettes from the magazine to the reader and vice-versa. Photocells are used to identify and index to the desired tape cassette. The apparatus allows digital information stored on multiple cassettes to be processed without significant operator intervention.

Apparatus and method for loading and unloading multiple digital tape cassettes utilizing a removable magazine

DOEpatents

Lindenmeyer, Carl W.

1993-01-01

An apparatus and method to automate the handling of multiple digital tape cassettes for processing by commercially available cassette tape readers and recorders. A removable magazine rack stores a plurality of tape cassettes, and cooperates with a shuttle device that automatically inserts and removes cassettes from the magazine to the reader and vice-versa. Photocells are used to identify and index to the desired tape cassette. The apparatus allows digital information stored on multiple cassettes to be processed without significant operator intervention.

High data volume and transfer rate techniques used at NASA's image processing facility

NASA Technical Reports Server (NTRS)

Heffner, P.; Connell, E.; Mccaleb, F.

1978-01-01

Data storage and transfer operations at a new image processing facility are described. The equipment includes high density digital magnetic tape drives and specially designed controllers to provide an interface between the tape drives and computerized image processing systems. The controller performs the functions necessary to convert the continuous serial data stream from the tape drive to a word-parallel blocked data stream which then goes to the computer-based system. With regard to the tape packing density, 1.8 times 10 to the tenth data bits are stored on a reel of one-inch tape. System components and their operation are surveyed, and studies on advanced storage techniques are summarized.

Dry Process for Making Polyimide/ Carbon-and-Boron-Fiber Tape

NASA Technical Reports Server (NTRS)

Belvin, Harry L.; Cano, Roberto J.; Johnston, Norman J.; Marchello, Joseph M.

2003-01-01

A dry process has been invented as an improved means of manufacturing composite prepreg tapes that consist of high-temperature thermoplastic polyimide resin matrices reinforced with carbon and boron fibers. Such tapes are used (especially in the aircraft industry) to fabricate strong, lightweight composite-material structural components. The inclusion of boron fibers results in compression strengths greater than can be achieved by use of carbon fibers alone. The present dry process is intended to enable the manufacture of prepreg tapes (1) that contain little or no solvent; (2) that have the desired dimensions, fiber areal weight, and resin content; and (3) in which all of the fibers are adequately wetted by resin and the boron fibers are fully encapsulated and evenly dispersed. Prepreg tapes must have these properties to be useable in the manufacture of high-quality composites by automated tape placement. The elimination of solvent and the use of automated tape placement would reduce the overall costs of manufacturing.

The effect of the YBCO-PST composite composition on the superconducting carrier concentration determined by microwave studies under high pressure

NASA Astrophysics Data System (ADS)

Krupski, M.; Stankowski, J.; Przybył, S.; Andrzejewski, B.; Kaczmarek, A.; Hilczer, B.; Marfaing, J.; Caranoni, C.

1999-07-01

The effect of hydrostatic pressure ( p<0.6 GPa) on the superconducting critical temperature Tc in YBa 2Cu 3O 7- δ-Pb(Sc 0.5Ta 0.5)O 3 (YBCO-PST) composite is measured by the method of magnetically modulated microwave absorption (MMMA). The Tc dependence on the PST fraction in weight x (0, 0.25, 0.5 and 0.75) is approximated by an inverted parabola function whereas the influence of pressure on Tc is represented by the equation: d Tc/d p=0.61(2)-1.72(6) x. The result may be explained assuming that PST phase in YBCO-PST composite influences the superconducting carrier concentration similar to the chemical substitution in YBa 2Cu 3O 7 [J.J. Neumeier, H.A. Zimmermann, Phys. Rev. B 47 (1993) 8385]. It is suggested that ions from PST diffuse to YBCO cell during the sintering of the composite.

Transport properties of ultrathin YBa2Cu3O7 -δ nanowires: A route to single-photon detection

NASA Astrophysics Data System (ADS)

Arpaia, Riccardo; Golubev, Dmitri; Baghdadi, Reza; Ciancio, Regina; Dražić, Goran; Orgiani, Pasquale; Montemurro, Domenico; Bauch, Thilo; Lombardi, Floriana

2017-08-01

We report on the growth and characterization of ultrathin YBa2Cu3O7 -δ (YBCO) films on MgO (110) substrates, which exhibit superconducting properties at thicknesses down to 3 nm. YBCO nanowires, with thicknesses down to 10 nm and widths down to 65 nm, have also been successfully fabricated. The nanowires protected by a Au capping layer show superconducting properties close to the as-grown films and critical current densities, which are limited by only vortex dynamics. The 10-nm-thick YBCO nanowires without the Au capping present hysteretic current-voltage characteristics, characterized by a voltage switch which drives the nanowires directly from the superconducting to the normal state. We associate such bistability to the presence of localized normal domains within the superconductor. The presence of the voltage switch in ultrathin YBCO nanostructures, characterized by high sheet resistance values and high critical current values, makes our nanowires very attractive devices to engineer single-photon detectors.

GSFC specification electronic data processing magnetic recording tape

NASA Technical Reports Server (NTRS)

Tinari, D. F.; Perry, J. L.

1980-01-01

The design requirements are given for magnetic oxide coated, electronic data processing tape, wound on reels. Magnetic recording tape types covered by this specification are intended for use on digital tape transports using the Non-Return-to-Zero-change-on-ones (NRZI) recording method for recording densities up to and including 800 characters per inch (cpi) and the Phase-Encoding (PE) recording method for a recording density of 1600 cpi.

Contribution of ion beam analysis methods to the development of second generation high temperature superconducting wires

NASA Astrophysics Data System (ADS)

Usov, I. O.; Arendt, P. N.; Foltyn, S. R.; Stan, L.; DePaula, R. F.; Holesinger, T. G.

2010-06-01

One of the crucial steps in the second generation high temperature superconducting wire program was development of the buffer-layer architecture. The architecture designed at the Superconductivity Technology Center at Los Alamos National Laboratory consists of several oxide layers wherein each layer plays a specific role, namely: nucleation layer, diffusion barrier, biaxially textured template, and intermediate layer providing a suitable lattice match to the superconducting Y 1Ba 2Cu 3O 7 (YBCO) compound. This report demonstrates how a wide range of ion beam analysis techniques (SIMS, RBS, channeling, PIXE, PIGE, NRA and ERD) was employed for analysis of each buffer layer and the YBCO film. These results assisted in understanding of a variety of physical processes occurring during the buffer layer fabrication and helped to optimize the buffer-layer architecture as a whole.

Levitation forces of a bulk YBCO superconductor in gradient varying magnetic fields

NASA Astrophysics Data System (ADS)

Jiang, J.; Gong, Y. M.; Wang, G.; Zhou, D. J.; Zhao, L. F.; Zhang, Y.; Zhao, Y.

2015-09-01

The levitation forces of a bulk YBCO superconductor in gradient varying high and low magnetic fields generated from a superconducting magnet were investigated. The magnetic field intensity of the superconducting magnet was measured when the exciting current was 90 A. The magnetic field gradient and magnetic force field were both calculated. The YBCO bulk was cooled by liquid nitrogen in field-cooling (FC) and zero-field-cooling (ZFC) condition. The results showed that the levitation forces increased with increasing the magnetic field intensity. Moreover, the levitation forces were more dependent on magnetic field gradient and magnetic force field than magnetic field intensity.

Development of YBCO Superconductor for Electric Systems: Cooperative Research and Development Final Report, CRADA Number CRD-04-150

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharya, R.

2013-03-01

The proposed project will be collaborative in exploration of high temperature superconductor oxide films between SuperPower, Inc. and the National Renewable Energy Laboratory. This CRADA will attempt to develop YBCO based high temperature oxide technology.

Solar greenhouse workshop; video documentary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Austin, B.; Devine B.; Taylor, C.

1980-01-01

A 38 minute video-tape documentary of the building of an attached solar greenhouse is presented. The tape follows the construction process from foundation preparation to greenhouse completion. The tape allows greater outreach to potential builders of solar greenhouses than a conventional construction workshop. It allows viewers to appreciate the simplicity of construction, and encourages, by example, interested people to start building. The process of making the documentary is briefly described, as are its potential uses. Copies of the video-tape are available, for the cost of the tape alone, from Antioch Video, Antioch College, Yellow Springs, Ohio 45387.

Technique minimizes the effects of dropouts on telemetry records

NASA Technical Reports Server (NTRS)

Anderson, T. O.; Hurd, W. J.

1972-01-01

Recorder deficiencies are minimized by using two-channel system to prepare two tapes, each having noise, wow and flutter, and dropout characteristics of channel on which it was made. Processing tapes by computer and combining signals from two channels produce single tape free of dropouts caused by recording process.

APQ-102 imaging radar digital image quality study

NASA Technical Reports Server (NTRS)

Griffin, C. R.; Estes, J. M.

1982-01-01

A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer.

Generation and physical characteristics of the ERTS MSS system corrected computer compatible tapes

NASA Technical Reports Server (NTRS)

Thomas, V. L.

1973-01-01

The generation and format are discussed of the ERTS system corrected multispectral scanner computer compatible tapes. The discussion includes spacecraft sensors, scene characteristics, data transmission, and conversion of data to computer compatible tapes at the NASA Data Processing Facility. Geometeric and radiometric corrections, tape formats, and the physical characteristics of the tapes are also included.

Superconducting YBa2Cu3O7- δ Thin Film Detectors for Picosecond THz Pulses

NASA Astrophysics Data System (ADS)

Probst, P.; Scheuring, A.; Hofherr, M.; Wünsch, S.; Il'in, K.; Semenov, A.; Hübers, H.-W.; Judin, V.; Müller, A.-S.; Hänisch, J.; Holzapfel, B.; Siegel, M.

2012-06-01

Ultra-fast THz detectors from superconducting YBa2Cu3O7- δ (YBCO) thin films were developed to monitor picosecond THz pulses. YBCO thin films were optimized by the introduction of CeO2 and PrBaCuO buffer layers. The transition temperature of 10 nm thick films reaches 79 K. A 15 nm thick YBCO microbridge (transition temperature—83 K, critical current density at 77 K—2.4 MA/cm2) embedded in a planar log-spiral antenna was used to detect pulsed THz radiation of the ANKA storage ring. First time resolved measurements of the multi-bunch filling pattern are presented.

High Fidelity Tape Transfer Printing Based On Chemically Induced Adhesive Strength Modulation

NASA Astrophysics Data System (ADS)

Sim, Kyoseung; Chen, Song; Li, Yuhang; Kammoun, Mejdi; Peng, Yun; Xu, Minwei; Gao, Yang; Song, Jizhou; Zhang, Yingchun; Ardebili, Haleh; Yu, Cunjiang

2015-11-01

Transfer printing, a two-step process (i.e. picking up and printing) for heterogeneous integration, has been widely exploited for the fabrication of functional electronics system. To ensure a reliable process, strong adhesion for picking up and weak or no adhesion for printing are required. However, it is challenging to meet the requirements of switchable stamp adhesion. Here we introduce a simple, high fidelity process, namely tape transfer printing(TTP), enabled by chemically induced dramatic modulation in tape adhesive strength. We describe the working mechanism of the adhesion modulation that governs this process and demonstrate the method by high fidelity tape transfer printing several types of materials and devices, including Si pellets arrays, photodetector arrays, and electromyography (EMG) sensors, from their preparation substrates to various alien substrates. High fidelity tape transfer printing of components onto curvilinear surfaces is also illustrated.

Feasibility of Carbon Fiber/PEEK Composites for Cryogenic Fuel Tank Applications

NASA Astrophysics Data System (ADS)

Doyle, K.; Doyle, A.; O Bradaigh, C. M.; Jaredson, D.

2012-07-01

This paper investigates the feasibility of CF/PEEK composites for manufacture of cryogenic fuel tanks for Next Generation Space Launchers. The material considered is CF/PEEK tape from Suprem SA and the proposed manufacturing process for the fuel tank is Automated Tape Placement. Material characterization was carried out on test laminates manufactured in an autoclave and also by Automated Tape Placement with in-situ consolidation. The results of the two processes were compared to establish if there is any knock down in properties for the automated tape placement process. A permeability test rig was setup with a helium leak detector and the effect of thermal cycling on the permeability properties of CF/PEEK was measured. A 1/10th scale demonstrator was designed and manufactured consisting of a cylinder manufactured by automated tape placement and an upper dome manufactured by autoclave processing. The assembly was achieved by Amorphous Interlayer Bonding with PEI.

Low energy electron beam processing of YBCO thin films

NASA Astrophysics Data System (ADS)

Chromik, Š.; Camerlingo, C.; Sojková, M.; Štrbík, V.; Talacko, M.; Malka, I.; Bar, I.; Bareli, G.; Jung, G.

2017-02-01

Effects of low energy 30 keV electron irradiation of superconducting YBa2Cu3O7-δ thin films have been investigated by means of transport and micro-Raman spectroscopy measurements. The critical temperature and the critical current of 200 nm thick films initially increase with increasing fluency of the electron irradiation, reach the maximum at fluency 3 - 4 × 1020 electrons/cm2, and then decrease with further fluency increase. In much thinner films (75 nm), the critical temperature increases while the critical current decreases after low energy electron irradiation with fluencies below 1020 electrons/cm2. The Raman investigations suggest that critical temperature increase in irradiated films is due to healing of broken Cusbnd O chains that results in increased carrier's concentration in superconducting CuO2 planes. Changes in the critical current are controlled by changes in the density of oxygen vacancies acting as effective pinning centers for flux vortices. The effects of low energy electron irradiation of YBCO turned out to result from a subtle balance of many processes involving oxygen removal, both by thermal activation and kick-off processes, and ordering of chains environment by incident electrons.

Spacelab Data Processing Facility

NASA Technical Reports Server (NTRS)

1983-01-01

The Spacelab Data Processing Facility (SDPF) processes, monitors, and accounts for the payload data from Spacelab and other Shuttle missions and forwards relevant data to various user facilities worldwide. The SLDPF is divided into the Spacelab Input Processing System (SIPS) and the Spacelab Output Processing System (SOPS). The SIPS division demultiplexes, synchronizes, time tags, quality checks, accounts for the data, and formats the data onto tapes. The SOPS division further edits, blocks, formats, and records the data on tape for shipment to users. User experiments must conform to the Spacelab's onboard High Rate Multiplexer (HRM) format for maximum process ability. Audio, analog, instrumentation, high density, experiment data, input/output data, quality control and accounting, and experimental channel tapes along with a variety of spacelab ancillary tapes are provided to the user by SLDPF.

YBCO film deposition on very large areas up to 20 × 20 cm2

NASA Astrophysics Data System (ADS)

Kinder, H.; Berberich, P.; Prusseit, W.; Rieder-Zecha, S.; Semerad, R.; Utz, B.

1997-08-01

In the last decade we have developed thermal reactive co-evaporation as a technique to produce high quality YBCO and other oxide films of very large size up to 9 inches in diameter. This was achieved by intermittent deposition and reaction with oxygen using a heater which rotates the substrate in and out of an oxygen pocket. Even larger substrates, e. g. coated conductors, cannot be rotated. Therefore we have recently developed a new setup where the substrate is held fixed, and the oxygen pocket is set in linear reciprocation. This technique allows simultaneous deposition on a square of 20×20 cm 2. Moreover, we have developed an instant refill mechanism for the thermal boats, and stable rate control by atomic absorption spectroscopy (AAS), in order to obtain a continuous process suitable for small scale mass production.

Effect of superconducting spacer layer thickness on magneto-transport and magnetic properties of La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/YBa{sub 2}Cu{sub 3}O{sub 7}/La{sub 0.7}Sr{sub 0.3}MnO{sub 3} heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sharma, Minaxi, E-mail: meenanith@gmail.com; Sharma, K. K., E-mail: kknitham@gmail.com; Pandey, Pankaj K.

2014-01-07

We have studied the magneto-transport and magnetic properties of LSMO/YBCO/LSMO trilayers on LaAlO{sub 3} (001) substrate, deposited using pulsed laser deposition technique. From x-ray diffraction measurements, it is confirmed that the grown trilayer films are single phase natured. The temperature dependent resistivity shows a metallic behavior below 350 K. At low temperature from resistivity fitted data, we observe that electron-electron, electron-phonon, and electron-magnon interactions are the main factors for scattering of carriers. The ferromagnetic LSMO layers suppress the critical temperature of YBCO spacer layer. We observe maximum magnetoresistance value ∼49% at 250 K for LSMO(200 nm)/YBCO(50 nm)/LSMO(200 nm) trilayer. Magnetization measurements reveal that at roommore » temperature the YBCO spacer layer is allowing the LSMO layers to interact antiferromagnetically.« less

Probing localized strain in solution-derived YB a2C u3O7 -δ nanocomposite thin films

NASA Astrophysics Data System (ADS)

Guzman, Roger; Gazquez, Jaume; Mundet, Bernat; Coll, Mariona; Obradors, Xavier; Puig, Teresa

2017-07-01

Enhanced pinning due to nanoscale strain is unique to the high-Tc cuprates, where pairing may be modified with lattice distortion. Therefore a comprehensive understanding of the defect landscape is required for a broad range of applications. However, determining the type and distribution of defects and their associated strain constitutes a critical task, and for this aim, real-space techniques for atomic resolution characterization are necessary. Here, we use scanning transmission electron microscopy (STEM) to study the atomic structure of individual defects of solution-derived YB a2C u3O7 (YBCO) nanocomposites, where the inclusion of incoherent secondary phase nanoparticles within the YBCO matrix dramatically increases the density of Y1B a2C u4O8 (Y124) intergrowths, the commonest defect in YBCO thin films. The formation of the Y124 is found to trigger a concatenation of strain-derived interactions with other defects and the concomitant nucleation of intrinsic defects, which weave a web of randomly distributed nanostrained regions that profoundly transform the vortex-pinning landscape of the YBCO nanocomposite thin films.

Superconductivity-induced magnetization depletion in a ferromagnet through an insulator in a ferromagnet-insulator-superconductor hybrid oxide heterostructure.

PubMed

Prajapat, C L; Singh, Surendra; Paul, Amitesh; Bhattacharya, D; Singh, M R; Mattauch, S; Ravikumar, G; Basu, S

2016-05-21

Coupling between superconducting and ferromagnetic states in hybrid oxide heterostructures is presently a topic of intense research. Such a coupling is due to the leakage of the Cooper pairs into the ferromagnet. However, tunneling of the Cooper pairs though an insulator was never considered plausible. Using depth sensitive polarized neutron reflectivity we demonstrate the coupling between superconductor and magnetic layers in epitaxial La2/3Ca1/3MnO3 (LCMO)/SrTiO3/YBa2Cu3O7-δ (YBCO) hybrid heterostructures, with SrTiO3 as an intervening oxide insulator layer between the ferromagnet and the superconductor. Measurements above and below the superconducting transition temperature (TSC) of YBCO demonstrate a large modulation of magnetization in the ferromagnetic layer below the TSC of YBCO in these heterostructures. This work highlights a unique tunneling phenomenon between the epitaxial layers of an oxide superconductor (YBCO) and a magnetic layer (LCMO) through an insulating layer. Our work would inspire further investigations on the fundamental aspect of a long range order of the triplet spin-pairing in hybrid structures.

Crossover between superconductivity and magnetism in SrRuO3 mesocrystal embedded YBa2Cu3O7-x heterostructures.

PubMed

Suresh, Vandrangi; Lin, Jheng-Cyuan; Liu, Heng-Jui; Zhang, Zaoli; Chiang, Ping-Chih; Hsun, Yu-Ching; Chen, Yi-Chun; Lin, Jiunn-Yuan; Chu, Ying-Hao

2016-11-03

The competition between superconductivity and ferromagnetism poses great challenges and has attracted renewed interest for applications in novel spintronic devices. In order to emphasize their interactions, we fabricated a heterostructure composed of superconducting YBa 2 Cu 3 O 7-δ (YBCO) film embedded with itinerant ferromagnetic SrRuO 3 (SRO) mesocrystals. Starting from a doping concentration of 10 vol% of SRO mesocrystal in a YBCO matrix, corresponding to the density of SRO nanocrystals ∼5 × 10 9 cm -2 , which exhibits the typical characteristic of a metal-superconductor transition, and then increasing the magnetic interactions as a function of SRO embedment, the electronic correlation and the interplay between superconductivity and magnetism throughout the temperature regime were investigated. A metal-insulator transition in the normal state of YBCO and a crossover between superconductivity and magnetism at low temperatures were found upon increasing the density of nano-size SRO crystallites in the YBCO matrix as a consequence of competing interactions between these two ordered phases.

Temperature dependence of superfluid density in YBa 2Cu 3O 7- δ and Y 0.7Ca 0.3Ba 2Cu 3O 7- δ thin films: A doping dependence study of the linear slope

NASA Astrophysics Data System (ADS)

Lai, L. S.; Juang, J. Y.; Wu, K. H.; Uen, T. M.; Gou, Y. S.

2005-11-01

By using a microstrip ring resonator to measure the temperature dependence of the in-plane magnetic penetration depth λ(T) in YBa2Cu3O7-δ (YBCO) and Y0.7Ca0.3Ba2Cu3O7-δ (Ca-YBCO) epitaxially grown thin films, the linear temperature dependence of the superfluid density ρs/m∗ ≡ 1/λ2(T) was observed from the under- to the overdoped regime at the temperatures below T/Tc ≈ 0.3 . For the underdoped regime of YBCO and Ca-YBCO thin films, the magnitude of the slope d(1/λ2(T))/dT is insensitive to doping, and it can be treated in the framework of projected d-density-wave model. Combining these slope values with the thermal conductivity measurements, the Fermi-liquid correction factor α2 from the Fermi-liquid model, suggested by Wen and Lee, was revealed here with various doping levels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Norsworthy, R.

A rating system was developed for several coating types used for underground pipeline systems. Consideration included soil stress, adhesion, surface preparation, cathodic protection (CP) shielding, CP requirements, handling and construction, repair, field joint system, bends and other components, and the application process. Polyethylene- and polyvinyl chloride-backed tapes, woven polyolefin geotextile fabric (WGF)-backed tapes, hot-applied tapes, petrolatum- and wax-based tapes, and shrink sleeves were evaluated. WGF-backed tapes had the highest rating.

Creation of high-pinning microstructures in post production YBCO coated conductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welp, Ulrich; Miller, Dean J.; Kwok, Wai-Kwong

A method comprising irradiating a polycrystalline rare earth metal-alkaline earth metal-transition metal-oxide superconductor layer with protons having an energy of 1 to 6 MeV. The irradiating process produces an irradiated layer that comprises randomly dispersed defects with an average diameter in the range of 1-10 nm.

EROS to universal tape conversion processor

NASA Technical Reports Server (NTRS)

Obrien, S. O. (Principal Investigator)

1980-01-01

The function of the EROS processor is to allow a user to select a specific area from a full frame LANDSAT image which is written on tape in the EROS format. The area of interest is read from the EROS formatted tape and converted to the JSC Universal format and written onto another tape. This tape can then be read by the IMDACS processing system and normal analysis can be performed.

Generation and physical characteristics of the Landsat 1 and 2 MSS computer compatible tapes

NASA Technical Reports Server (NTRS)

Thomas, V. L.

1975-01-01

The generation and format is discussed of the Landsat 1 and 2 system corrected multispectral scanner computer compatible tapes. Included in the discussion are the spacecraft sensors, scene characteristics, the transmission of data, and the conversion of the data to computer compatible tapes at the NASA Data Processing Facility. Geometric and radiometric corrections, tape formats, and the physical characteristics of the tape are also described.

Process for manufacturing a lithium alloy electrochemical cell

DOEpatents

Bennett, William R.

1992-10-13

A process for manufacturing a lithium alloy, metal sulfide cell tape casts slurried alloy powders in an organic solvent containing a dissolved thermoplastic organic binder onto casting surfaces. The organic solvent is then evaporated to produce a flexible tape removable adhering to the casting surface. The tape is densified to increase its green strength and then peeled from the casting surface. The tape is laminated with a separator containing a lithium salt electrolyte and a metal sulfide electrode to form a green cell. The binder is evaporated from the green cell at a temperature lower than the melting temperature of the lithium salt electrolyte. Lithium alloy, metal sulfide and separator powders may be tape cast.

Effect of oxygen partial pressure on superconducting properties of Bi-2212/Ag tapes prepared by doctor-blade method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inoue, N.; Okada, M.; Higashiyama, K.

1997-06-01

The authors have investigated the relationship between oxygen partial pressure (P{sub O{sub 2}}) during the partial-melting process and superconducting properties for doctor-blade processed Bi-2212/Ag tapes. Tapes were heat-treated at various P{sub O{sub 2}} value of 0.01-1.00 atm. The DTA results for the doctor-blade tapes showed the melting point of the oxide rose with increasing P{sub O{sub 2}}. Correspondingly, the optimum heat-treatment temperature also increased with increasing P{sub O{sub 2}}. The tapes at P{sub O{sub 2}}=1.00 atm had the highest J{sub c} values of over 10{sup 5} A/cm{sup 2} at conditions of 4.2K, 10T, and their a.c. susceptibility showed a sharpmore » transition indicating improved intergrain coupling. Examination of cross sections for tapes melted above 0.20atm PO{sub 2} showed the good crystal alignment. From these results, it was concluded that processing at high PO{sub 2} was an effective method to obtain good superconducting properties for doctor-blade tapes.« less

High Tc YBCO superconductor deposited on biaxially textured Ni substrate

DOEpatents

Budai, John D.; Christen, David K.; Goyal, Amit; He, Qing; Kroeger, Donald M.; Lee, Dominic F.; List, III, Frederick A.; Norton, David P.; Paranthaman, Mariappan; Sales, Brian C.; Specht, Eliot D.

1999-01-01

A superconducting article includes a biaxially-textured Ni substrate, and epitaxial buffer layers of Pd (optional), CeO.sub.2 and YSZ, and a top layer of in-plane aligned, c-axis oriented YBCO having a critical current density (J.sub.c) in the range of at least 100,000 A/cm.sup.2 at 77 K.

Disorder-controlled superconductivity at YBa2Cu3O7/SrTiO3 interfaces

NASA Astrophysics Data System (ADS)

Garcia-Barriocanal, J.; Perez-Muñoz, A. M.; Sefrioui, Z.; Arias, D.; Varela, M.; Leon, C.; Pennycook, S. J.; Santamaria, J.

2013-06-01

We examine the effect of interface disorder in suppressing superconductivity in coherently grown ultrathin YBa2Cu3O7 (YBCO) layers on SrTiO3 (STO) in YBCO/STO superlattices. The termination plane of the STO is TiO2 and the CuO chains are missing at the interface. Disorder (steps) at the STO interface cause alterations of the stacking sequence of the intracell YBCO atomic layers. Stacking faults give rise to antiphase boundaries which break the continuity of the CuO2 planes and depress superconductivity. We show that superconductivity is directly controlled by interface disorder outlining the importance of pair breaking and localization by disorder in ultrathin layers.

Improved Epitaxy and Surface Morphology in YBa2Cu3Oy Thin Films Grown on Double Buffered Si Wafers

NASA Astrophysics Data System (ADS)

Gao, J.; Kang, L.; Wong, H. Y.; Cheung, Y. L.; Yang, J.

Highly epitaxial thin films of YBCO have been obtained on silicon wafers using a Eu2CuO4/YSZ (yttrium-stabilized ZrO2) double buffer. Our results showed that application of such a double buffer can significantly enhance the epitaxy of grown YBCO. It also leads to an excellent surface morphology. The average surface roughness was found less than 5 nm in a large range. The results of X-ray small angle reflection and positron spectroscpy demonstrate a very clear and flat interface between YBCO and buffer layers. The Eu2CuO4/YSZ double buffer could be promising for coating high-TC superconducting films on various reactive substrates.

The Carbon Monoxide Tape Recorder

NASA Technical Reports Server (NTRS)

Schoeberl, M. R.; Duncan, B. N.; Douglass, A. R.; Waters, J.; Livesey, N.; Read, W.; Filipiak, M.

2006-01-01

Using Aura MLS data we have identified the stratospheric tape recorder in carbon monoxide (CO). Unlike the water vapor tape recorder, which is controlled by upper troposphere processes, the CO tape recorder is linked to seasonal biomass burning. Since CO has a lifetime of only a few months, the CO tape recorder barely extends above 20 km. The tape head for CO appears to be close to 360K near the same location as the water vapor tape head [Read et al, 20041. Both tape heads are below the equatorial cold point tropopause but above the base of the tropical tropopause layer. The tape recorder signal becomes more distinct from 360K to 380K suggesting that convective detrainment of plays a decreasingly important role with altitude. The Global Modeling Initiative chemical transport model forced by the climatology of biomass burning reproduces the CO tape recorder.

A Dry Powder Process for Preparing Uni-Tape Prepreg from Polymer Powder Coated Filamentary Towpregs

NASA Technical Reports Server (NTRS)

Wilkinson, Steven P. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

1995-01-01

A process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs is provided. A plurality of polymer powder coated filamentary towpregs are provided. The towpregs are collimated so that each towpreg is parallel. The sandwich is heated to a temperature wherein the polymer flows and intimately contacts the filaments and pressure is repeatedly applied perpendicularly to the sandwich with a longitudinal oscillating action wherein the filaments move apart and the polymer wets the filaments forming a uni-tape prepreg. The uni-tape prepreg is subsequently cooled.

One-step Tape Casting of Composites via Slurry on Fiber

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III

2001-01-01

A process by which metal matrix composites can be made was presented. The process involves putting a powder slurry on fibers to make a precursor green tape. These green tapes are cut, stacked and hot pressed to form the fully dense composite. A computer program was presented which enables complete quantification and control of the process. Once some easily obtained properties of the slurry and its behavior are determined (such as the shrinkage from the wet to green state, and the density of the green tape) modification of the fiber spacing and blade height give the maker precise control of fiber volume fraction, and fiber architecture in the composite. The process was shown to be accurate and flexible through the production of a wide variety of volume fraction fiber composites made from a wide variety of fibers and powders. The most time consuming step of the tape casting process (other than hot pressing) was winding the fiber on the drum. The tape casting techniques developed resulted in high quality metal matrix composites, with ultimate tensile strength in the range of 215 ksi (1477 MPa), a strain at failure of 1.15 percent, and in fatigue at room temperature 0 to 120 ksi, n = 0.3 Hz, a 4-ply Ti-24Al-11Nb/SCS-6, 32 vol% fiber tape cast composite lasted 202,205 cycles with a maximum strain on the 100th cycle of 0.43 percent.

The Dynomak: An advanced spheromak reactor system with imposed-dynamo current drive and next-generation nuclear power technologies

NASA Astrophysics Data System (ADS)

Sutherland, D. A.; Jarboe, T. R.; Marklin, G.; Morgan, K. D.; Nelson, B. A.

2013-10-01

A high-beta spheromak reactor system has been designed with an overnight capital cost that is competitive with conventional power sources. This reactor system utilizes recently discovered imposed-dynamo current drive (IDCD) and a molten salt blanket system for first wall cooling, neutron moderation and tritium breeding. Currently available materials and ITER developed cryogenic pumping systems were implemented in this design on the basis of technological feasibility. A tritium breeding ratio of greater than 1.1 has been calculated using a Monte Carlo N-Particle (MCNP5) neutron transport simulation. High-temperature superconducting tapes (YBCO) were used for the equilibrium coil set, substantially reducing the recirculating power fraction when compared to previous spheromak reactor studies. Using zirconium hydride for neutron shielding, a limiting equilibrium coil lifetime of at least thirty full-power years has been achieved. The primary FLiBe loop was coupled to a supercritical carbon dioxide Brayton cycle due to attractive economics and high thermal efficiencies. With these advancements, an electrical output of 1000 MW from a thermal output of 2486 MW was achieved, yielding an overall plant efficiency of approximately 40%. A paper concerning the Dynomak reactor design is currently being reviewed for publication.

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields.

PubMed

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (H c2 ) and critical temperature (T c ). The critical current (I c ) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new I c measurement system that can carry out accurate I c measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The I c measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa 2 Cu 3 O 7-x (YBCO) tapes I c determination with different temperatures and magnetic fields.

Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields

NASA Astrophysics Data System (ADS)

Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

2018-01-01

High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (Hc2) and critical temperature (Tc). The critical current (Ic) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new Ic measurement system that can carry out accurate Ic measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The Ic measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa2Cu3O7-x(YBCO) tapes Ic determination with different temperatures and magnetic fields.

Editing of EIA coded, numerically controlled, machine tool tapes

NASA Technical Reports Server (NTRS)

Weiner, J. M.

1975-01-01

Editing of numerically controlled (N/C) machine tool tapes (8-level paper tape) using an interactive graphic display processor is described. A rapid technique required for correcting production errors in N/C tapes was developed using the interactive text editor on the IMLAC PDS-ID graphic display system and two special programs resident on disk. The correction technique and special programs for processing N/C tapes coded to EIA specifications are discussed.

High current density electropolishing in the preparation of highly smooth substrate tapes for coated conductors

DOEpatents

Kreiskott, Sascha [Los Alamos, NM; Matias, Vladimir [Santa Fe, NM; Arendt, Paul N [Los Alamos, NM; Foltyn, Stephen R [Los Alamos, NM; Bronisz, Lawrence E [Los Alamos, NM

2009-03-31

A continuous process of forming a highly smooth surface on a metallic tape by passing a metallic tape having an initial roughness through an acid bath contained within a polishing section of an electropolishing unit over a pre-selected period of time, and, passing a mean surface current density of at least 0.18 amperes per square centimeter through the metallic tape during the period of time the metallic tape is in the acid bath whereby the roughness of the metallic tape is reduced. Such a highly smooth metallic tape can serve as a base substrate in subsequent formation of a superconductive coated conductor.

Optimization of Tape Winding Process Parameters to Enhance the Performance of Solid Rocket Nozzle Throat Back Up Liners using Taguchi's Robust Design Methodology

NASA Astrophysics Data System (ADS)

Nath, Nayani Kishore

2017-08-01

The throat back up liners is used to protect the nozzle structural members from the severe thermal environment in solid rocket nozzles. The throat back up liners is made with E-glass phenolic prepregs by tape winding process. The objective of this work is to demonstrate the optimization of process parameters of tape winding process to achieve better insulative resistance using Taguchi's robust design methodology. In this method four control factors machine speed, roller pressure, tape tension, tape temperature that were investigated for the tape winding process. The presented work was to study the cogency and acceptability of Taguchi's methodology in manufacturing of throat back up liners. The quality characteristic identified was Back wall temperature. Experiments carried out using L 9 ' (34) orthogonal array with three levels of four different control factors. The test results were analyzed using smaller the better criteria for Signal to Noise ratio in order to optimize the process. The experimental results were analyzed conformed and successfully used to achieve the minimum back wall temperature of the throat back up liners. The enhancement in performance of the throat back up liners was observed by carrying out the oxy-acetylene tests. The influence of back wall temperature on the performance of throat back up liners was verified by ground firing test.

Planetary image conversion task

NASA Technical Reports Server (NTRS)

Martin, M. D.; Stanley, C. L.; Laughlin, G.

1985-01-01

The Planetary Image Conversion Task group processed 12,500 magnetic tapes containing raw imaging data from JPL planetary missions and produced an image data base in consistent format on 1200 fully packed 6250-bpi tapes. The output tapes will remain at JPL. A copy of the entire tape set was delivered to US Geological Survey, Flagstaff, Ariz. A secondary task converted computer datalogs, which had been stored in project specific MARK IV File Management System data types and structures, to flat-file, text format that is processable on any modern computer system. The conversion processing took place at JPL's Image Processing Laboratory on an IBM 370-158 with existing software modified slightly to meet the needs of the conversion task. More than 99% of the original digital image data was successfully recovered by the conversion task. However, processing data tapes recorded before 1975 was destructive. This discovery is of critical importance to facilities responsible for maintaining digital archives since normal periodic random sampling techniques would be unlikely to detect this phenomenon, and entire data sets could be wiped out in the act of generating seemingly positive sampling results. Reccomended follow-on activities are also included.

Fabrication of Large YBCO Superconducting Disks

NASA Technical Reports Server (NTRS)

Koczor, Ronald J.; Noever, David A.; Robertson, Glen A.

1999-01-01

We have undertaken fabrication of large bulk items to develop a repeatable process and to provide test articles in laboratory experiments investigating reported coupling of electromagnetic fields with the local gravity field in the presence of rotating superconducting disks. A successful process was developed which resulted in fabrication of 30 cm diameter annular disks. The disks were fabricated of the superconductor YBa2Cu3O(7-x). Various material parameters of the disks were measured.

Fabrication of high T(sub c) superconductor thin film devices: Center director's discretionary fund

NASA Technical Reports Server (NTRS)

Sisk, R. C.

1992-01-01

This report describes a technique for fabricating superconducting weak link devices with micron-sized geometries etched in laser ablated Y1Ba2Cu3O(x) (YBCO) thin films. Careful placement of the weak link over naturally occurring grain boundaries exhibited in some YBCO thin films produces Superconducting Quantum Interference Devices (SQUID's) operating at 77 K.

Field Performance of an Optimized Stack of YBCO Square “Annuli” for a Compact NMR Magnet

PubMed Central

Hahn, Seungyong; Voccio, John; Bermond, Stéphane; Park, Dong-Keun; Bascuñán, Juan; Kim, Seok-Beom; Masaru, Tomita; Iwasa, Yukikazu

2011-01-01

The spatial field homogeneity and time stability of a trapped field generated by a stack of YBCO square plates with a center hole (square “annuli”) was investigated. By optimizing stacking of magnetized square annuli, we aim to construct a compact NMR magnet. The stacked magnet consists of 750 thin YBCO plates, each 40-mm square and 80- μm thick with a 25-mm bore, and has a Ø10 mm room-temperature access for NMR measurement. To improve spatial field homogeneity of the 750-plate stack (YP750) a three-step optimization was performed: 1) statistical selection of best plates from supply plates; 2) field homogeneity measurement of multi-plate modules; and 3) optimal assembly of the modules to maximize field homogeneity. In this paper, we present analytical and experimental results of field homogeneity and temporal stability at 77 K, performed on YP750 and those of a hybrid stack, YPB750, in which two YBCO bulk annuli, each Ø46 mm and 16-mm thick with a 25-mm bore, are added to YP750, one at the top and the other at the bottom. PMID:22081753

Trimming the electrical properties on nanoscale YBa2Cu3O7-x constrictions by focus ion beam technique

NASA Astrophysics Data System (ADS)

Lam, Simon K. H.; Bendavid, Avi; Du, Jia

2017-09-01

High temperature superconducting (HTS) nanostructure has a great potential in photon sensing at high frequency due to its fast recovery time. For maximising the coupling efficiency, the normal resistance of the nanostructure needs to be better matched to that of the thin-film antenna, which is typically few tens of ohm. We report on the fabrication of nanoscale high temperature superconducting YBa2Cu3O7-x (YBCO) constrictions using Gallium ion focus ion beam (FIB) technique. The FIB has been used to both remove the YBCO in lateral dimension and also tune its critical current and normal resistance by a combination of surface etching and implantation on the YBCO top layer. High critical current density of 2.5 MA/cm2 at 77 K can be obtained on YBCO nanobridges down to 100 nm in width. Subsequent trimming of the naobridges can lead to a normal resistance value over 50 Ω. Simulation of the Ga ion trajectory has also been performed to compare the measurement results. This method provides a simple step of fabricating nanoscale superconducting detectors such as hot electron bolometer.

Effect of crystallographical and geometrical changes of a ferrite head on magnetic signals during the sliding process with magnetic tape

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Buckley, D. H.; Tanaka, K.

1986-01-01

This paper reviews changes in the crystalline structure and geometry of lapped Mn-Zn ferrite heads in sliding contact with magnetic tape and the effects of these changes on magnetic signals. A highly textured, polycrystalline structure was produced on the surface of a single-crystal Mn-Zn ferrite head when it was finished with an aluminum oxide lapping tape. Sliding this lapped surface against a magnetic tape produced a nearly amorphous structure. The sliding process led to a degradation in readback signal of 1 to 2 dB (short-wavelength recording). Furthermore, wear of the magnetic head caused geometrical changes in the head surface. The signal read back with the worn magnetic head was sensitive to operating parameters such as head displacement and tape tension. A change in operating parameters created head-to-tape spacings and, consequently, excessive gains or losses in the readback signal.

Asymmetry of the velocity-matching steps in YBCO long Josephson junctions

NASA Astrophysics Data System (ADS)

Revin, L. S.; Pankratov, A. L.; Chiginev, A. V.; Masterov, D. V.; Parafin, A. E.; Pavlov, S. A.

2018-04-01

We carry out experimental and theoretical investigations into the effect of the vortex chain propagation on the current-voltage characteristics of YBa2Cu3O7-δ (YBCO) long Josephson junctions. Samples of YBCO Josephson junctions, fabricated on 24° [001]-tilt bicrystal substrates, have been measured. The improved technology has allowed us to observe and study the asymmetry of the current-voltage characteristics with opposite magnetic fields (Revin et al 2012 J. Appl. Phys. 114 243903), which we believe occurs due to anisotropy of bicrystal substrates (Kupriyanov et al (2013 JETP Lett. 95 289)). Specifically, we examine the flux-flow resonant steps versus the external magnetic field, and study the differential resistance and its relation to oscillation power for opposite directions of vortex propagation.

Enhancement in transport critical current density of ex situ PIT Ag/(Ba, K)Fe2As2 tapes achieved by applying a combined process of flat rolling and uniaxial pressing

NASA Astrophysics Data System (ADS)

Togano, Kazumasa; Gao, Zhaoshun; Matsumoto, Akiyoshi; Kumakura, Hiroaki

2013-11-01

We report that the transport critical current density Jc of ex situ powder-in-tube (PIT) processed (Ba, K)Fe2As2 (Ba-122) tapes can be significantly enhanced by applying uniaxial cold pressing at the final stage of deformation. The tapes were prepared by packing high quality precursor powder into a Ag tube, cycles of rolling and intermediate annealing, and pressing followed by the final heat treatment for sintering. The Jc values in applied magnetic fields were increased by almost one order of magnitude compared to the tapes processed without pressing, exceeding 104 A cm-2 at 4.2 K. We achieved the highest Jc (at 4.2 K and 10 T) of 2.1×104 A cm-2 among PIT-processed Fe-based wires and tapes reported so far. The Jc-H curves measured at higher temperatures maintain small field dependence up to around 20 K, suggesting that these tapes are promising for applications at higher temperatures as well as at liquid helium temperature. The microstructure investigations reveal that there are two possible causes of the large Jc enhancement by pressing: one is densification and the other is the change of crack structure. Optimization of processing parameters such as the reduction ratio of rolling and pressing is expected to yield further Jc enhancement.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Padaki, S.; Drzal, L.T.

The consolidation process in composites made out of powder impregnated tapes differs from that of other material forms because of the distribution of fiber and matrix in the unconsolidated state. A number of factors (e.g. time, pressure, particle size, volume fraction and viscosity) affect the efficiency of the consolidation of these tapes. This paper describes the development of a mathematical process model that describes the best set of parameters required for the consolidation of a given prepreg tape.

Abstracts of AF Materials Laboratory Reports

DTIC Science & Technology

1975-09-01

NO: TITLE: AUTHOR(S): CONTRACT NO; CONTRACTOR: AFML-TR-73-307 200,397 IMPROVED AUTOMATED TAPE LAYING MACHINE M. Poullos, W. J. Murray, D.L...AUTOMATED IMPROVED AUTOMATED TAPE LAYING MACHINE AUTOMATION AUTOMATION OF COATING PROCESSES FOR GAS TURBINE DLADcS AND VANES 203222/111 203072...IMP90VE0 TAPE LAYING MACHINE IMPP)VED AUTOMATED TAPE LAYING MACHINE A STUDY O^ THE STRESS-STRAIN TEHAVIOR OF GRAPHITE

Effective method to control the levitation force and levitation height in a superconducting maglev system

NASA Astrophysics Data System (ADS)

Yang, Peng-Tao; Yang, Wan-Min; Wang, Miao; Li, Jia-Wei; Guo, Yu-Xia

2015-11-01

The influence of the width of the middle magnet in the permanent magnet guideways (PMGs) on the levitation force and the levitation height of single-domain yttrium barium copper oxide (YBCO) bulks has been investigated at 77 K under the zero field cooled (ZFC) state. It is found that the largest levitation force can be obtained in the system with the width of the middle magnet of the PMG equal to the size of the YBCO bulk when the gap between the YBCO bulk and PMG is small. Both larger levitation force and higher levitation height can be obtained in the system with the width of the middle magnet of the PMG larger than the size of the YBCO bulk. The stiffness of the levitation force between the PMG and the YBCO bulk is higher in the system with a smaller width of the middle magnet in the PMG. These results provide an effective way to control the levitation force and the levitation height for the superconducting maglev design and applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51342001 and 50872079), the Key-grant Project of Chinese Ministry of Education (Grant No. 311033), the Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20120202110003), the Innovation Team in Shaanxi Province, China (Grant No. 2014KTC-18), and the Fundamental Research Funds for the Central Universities, China (Grant Nos. GK201101001 and GK201305014), and the Outstanding Doctoral Thesis Foundation Project of Shaanxi Normal University, China (Grant Nos. X2011YB08 and X2012YB05).

High Velocity Gas Gun

NASA Technical Reports Server (NTRS)

1988-01-01

A video tape related to orbital debris research is presented. The video tape covers the process of loading a High Velocity Gas Gun and firing it into a mounted metal plate. The process is then repeated in slow motion.

Influence of Sm2O3 microalloying and Yb contamination on Y211 particles coarsening and superconducting properties of IG YBCO bulk superconductors

NASA Astrophysics Data System (ADS)

Vojtkova, L.; Diko, P.; Kovac, J.; Vojtko, M.

2018-06-01

Single grain YBa2Cu3O7‑x (YBCO or Y123) bulk superconductors were produced by an infiltration growth process. The solid phase precursor was prepared by solid state synthesis from Y2O3 + BaCuO2 powders. The influence of the addition of Sm2O3 and YB contamination from the substrate on the microstructure and superconducting properties was analyzed. The dependences of Yb concentration on the distance from the bottom of the samples measured by energy dispersive spectroscopy microanalysis used in conjunction with scanning electron microscopy confirmed the contamination of the samples during the melting stage of the sample preparation. It is shown that the addition of Sm in low concentration and its combination with Yb from the substrate modify the coarsening of the Y211 particles as well as lead to the appearance of a secondary peak effect in the field dependences of the critical current density.

I-V Characteristics vs. Spatial Dissipation Maps in YBCO Grain Boundary on Bicrystal Substrates

NASA Astrophysics Data System (ADS)

Kwon, Chuhee; Yamamoto, Megumi; Pottish, Samuel; Haugan, Timothy; Barnes, Paul

2008-03-01

Grain boundary (GB) properties of YBCO films on SrTiO3 bicrystal substrates with 24 degree misorientations are examined by transport and scanning laser microscopy (SLM) techniques. Thermoelectric SLM clearly shows the location of grain boundaries, and variable temperature SLM confirms that GB has lower Tc. A series of I-V measured in superconducting states exhibit clear step-like features identified in earlier papers as sub-gap structures. The low temperature SLM shows a close relation between the step-like features and the local dissipation pattern in GB. We believe that the activation of Fiske steps is responsible for the step-like I-V, and SLM images show the spatial pattern of the self-excited resonance in GB. We will also discuss how Ca-doping and nanoparticle additions on YBCO affect the junction properties.

Conductor-backed coplanar waveguide resonators of Y-Ba-Cu-O and Tl-Ba-Ca-Cu-O on LaAlO3

NASA Technical Reports Server (NTRS)

Miranda, F. A.; Bhasin, K. B.; Stan, M. A.; Kong, K. S.; Itoh, T.

1992-01-01

Conductor-backed coplanar waveguide (CBCPW) resonators operating at 10.8 GHz have been fabricated from Tl-Ba-Ca-O (TBCCO) and Y-Ba-Cu-O (YBCO) thin films on LaAlO3. The resonators consist of a coplanar waveguide (CPW) patterned on the superconducting film side of the LaAlO3 substrate with a gold ground plane coated on the opposite side. These resonators were tested in the temperature range from 14 to 106 K. At 77 K, the best of our TBCCO and YBCO resonators have an unloaded quality factor (Qo) 7 and 4 times, respectively, larger than that of a similar all-gold resonator. In this study, the Qo's of the TBCCO resonators were larger than those of their YBCO counterparts throughout the aforementioned temperature range.

Impact of oxygen diffusion on superconductivity in YBa2Cu3O7 -δ thin films studied by positron annihilation spectroscopy

NASA Astrophysics Data System (ADS)

Reiner, M.; Gigl, T.; Jany, R.; Hammerl, G.; Hugenschmidt, C.

2018-04-01

The oxygen deficiency δ in YBa2Cu3O7 -δ (YBCO) plays a crucial role for affecting high-temperature superconductivity. We apply (coincident) Doppler broadening spectroscopy of the electron-positron annihilation line to study in situ the temperature dependence of the oxygen concentration and its depth profile in single crystalline YBCO film grown on SrTiO3 (STO) substrates. The oxygen diffusion during tempering is found to lead to a distinct depth dependence of δ , which is not accessible using x-ray diffraction. A steady state reached within a few minutes is defined by both, the oxygen exchange at the surface and at the interface to the STO substrate. Moreover, we reveal the depth-dependent critical temperature Tc in the as prepared and tempered YBCO film.

Modeling and Simulation of Voids in Composite Tape Winding Process Based on Domain Superposition Technique

NASA Astrophysics Data System (ADS)

Deng, Bo; Shi, Yaoyao

2017-11-01

The tape winding technology is an effective way to fabricate rotationally composite materials. Nevertheless, some inevitable defects will seriously influence the performance of winding products. One of the crucial ways to identify the quality of fiber-reinforced composite material products is examining its void content. Significant improvement in products' mechanical properties can be achieved by minimizing the void defect. Two methods were applied in this study, finite element analysis and experimental testing, respectively, to investigate the mechanism of how void forming in composite tape winding processing. Based on the theories of interlayer intimate contact and Domain Superposition Technique (DST), a three-dimensional model of prepreg tape void with SolidWorks has been modeled in this paper. Whereafter, ABAQUS simulation software was used to simulate the void content change with pressure and temperature. Finally, a series of experiments were performed to determine the accuracy of the model-based predictions. The results showed that the model is effective for predicting the void content in the composite tape winding process.

Dry powder process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs

NASA Technical Reports Server (NTRS)

Wilkinson, Steven P. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

1997-01-01

A process for preparing uni-tape prepreg from polymer powder coated filamentary towpregs is provided. A plurality of polymer powder coated filamentary towpregs are provided. The towpregs are collimated so that each towpreg is parallel. A material is applied to each side of the towpreg to form a sandwich. The sandwich is heated to a temperature wherein the polymer flows and intimately contacts the filaments and pressure is repeatedly applied perpendicularly to the sandwich with a longitudinal oscillating action wherein the filaments move apart and the polymer wets the filaments forming a uni-tape prepreg. The uni-tape prepreg is subsequently cooled.

Observation of dark pulses in 10 nm thick YBCO nanostrips presenting hysteretic current voltage characteristics

NASA Astrophysics Data System (ADS)

Ejrnaes, M.; Parlato, L.; Arpaia, R.; Bauch, T.; Lombardi, F.; Cristiano, R.; Tafuri, F.; Pepe, G. P.

2017-12-01

We have fabricated several 10 nm thick and 65 nm wide YBa2Cu3O7-δ (YBCO) nanostrips. The nanostrips with the highest critical current densities are characterized by hysteretic current voltage characteristics (IVCs) with a direct bistable switch from the zero-voltage to the finite voltage state. The presence of hysteretic IVCs allowed the observation of dark pulses due to fluctuations phenomena. The key role of the bistable behavior is its ability to transform a small disturbance (e.g. an intrinsic fluctuation) into a measurable transient signal, i.e. a dark pulse. On the contrary, in devices characterized by lower critical current density values, the IVCs are non-hysteretic and dark pulses have not been observed. To investigate the physical origin of the dark pulses, we have measured the bias current dependence of the dark pulse rate: the observed exponential increase with the bias current is compatible with mechanisms based on thermal activation of magnetic vortices in the nanostrip. We believe that the successful amplification of small fluctuation events into measurable signals in nanostrips of ultrathin YBCO is a milestone for further investigation of YBCO nanostrips for superconducting nanostrip single photon detectors and other quantum detectors for operation at higher temperatures.

Development of coated conductors by inclined substrate deposition

NASA Astrophysics Data System (ADS)

Balachandran, U.; Ma, B.; Li, M.; Fisher, B. L.; Koritala, R. E.; Miller, D. J.; Dorris, S. E.

2003-10-01

Inclined substrate deposition (ISD) offers the potential for rapid production of high-quality biaxially textured buffer layers suitable for YBa 2Cu 3O 7- δ (YBCO)-coated conductors. We have grown biaxially textured magnesium oxide (MgO) films on Hastelloy C276 (HC) substrates by ISD at deposition rates of 20-100 Å/s. Scanning electron microscopy of the ISD MgO films showed columnar grain structures with a roof-tile-shaped surface. X-ray pole figure analysis revealed that the c-axis of the ISD MgO films is titled at an angle ≈32° from the substrate normal. A small full-width at half maximum of ≈9° was observed for the φ-scan of MgO films. YBCO films were grown on ISD MgO buffered HC substrates by pulsed laser deposition and were determined to be biaxially aligned with the c-axis parallel to the substrate normal. The orientation relationship between the ISD template and the top YBCO film was investigated by X-ray pole figure analysis and transmission electron microscopy. A transport critical current density of Jc=5.5×10 5 A/cm 2 at 77 K in self-field was measured on a YBCO film that was 0.46-μm thick, 4-mm wide, 10-mm long.

Fully synthetic taped insulation cables

DOEpatents

Forsyth, Eric B.; Muller, Albert C.

1984-01-01

A high voltage oil-impregnated electrical cable with fully polymer taped insulation operable to 765 kV. Biaxially oriented, specially processed, polyethylene, polybutene or polypropylene tape with an embossed pattern is wound in multiple layers over a conductive core with a permeable screen around the insulation. Conventional oil which closely matches the dielectric constant of the tape is used, and the cable can be impregnated after field installation because of its excellent impregnation characteristics.

Evaluating exposures to complex mixtures of chemicals during a new production process in the plastics industry.

PubMed

Meijster, Tim; Burstyn, Igor; Van Wendel De Joode, Berna; Posthumus, Maarten A; Kromhout, Hans

2004-08-01

The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations. Principal component analyses (PCA) and linear regression were used to determine the emission sources of different chemicals found in the air samples. We showed that complex mixtures of chemicals were released, but most concentrations were below Dutch exposure limits. Based on the results of the principal component analyses, the chemicals found were divided into three groups. The first group consisted of short chain aliphatic hydrocarbons (C2-C6). The second group included larger hydrocarbons (C9-C11) and some cyclic hydrocarbons. The third group contained all aromatic and two aliphatic hydrocarbons. Regression analyses showed that emission of the first group of chemicals was associated with cleaning activities and the use of epoxy resins. The second and third group showed strong association with the type of tape used in the new tape winding process. High levels of CO and HCN (above exposure limits) were measured on one occasion when a different brand of impregnated polypropylene sulphide tape was used in the tape winding process. Plans exist to drastically increase production with the new tape winding process. This will cause exposure levels to rise and therefore further control measures should be installed to reduce release of these chemicals.

The effect of resolidification on preform optimized infiltration growth processed (Y, Nd, Sm, Gd)BCO, multi-grain bulk superconductor

NASA Astrophysics Data System (ADS)

Pavan Kumar Naik, S.; Seshu Bai, V.

2017-01-01

Controlling the microstructure of superconductors by incorporating the flux pinning centers and reducing the macro-defects to improve high field performance is the topic of recent research. In continuation, the preform optimized infiltration growth (POIG) processed YBa2Cu3O7-δ (YBCO) system, Y-site substituted with three mixed RE (Nd, Sm, Gd) elements is investigated. 20 wt.% of (Nd, Sm, Gd)2BaCuO5 were mixed with Y2BaCuO5 and POIG processed in reduced oxygen atmosphere to obtain YNSG superconductor. No seed is employed for crystal growth; hence the processed samples are multi-grained. Microstructural and compositional investigations on YNSG revealed the presence of different phases in the matrix as well as in precipitates which are of the order of submicron to 4 μm. A large fraction of macro-defects (∼6% of porosity) was observed in the YNSG sample. For reducing the unwanted macro-defects and refine the non-superconducting precipitates, processed YNSG sample is pressed and resolidified (by infiltrating the liquid phases once again) in an argon atmosphere and the structural, microstructural, elemental and superconducting properties are compared with YNSG and undoped samples. Due to spatial scatter in superconducting critical temperatures, caused by the distribution of different REBCO unit cells in YBCO, superconducting transition curve is sharp in YNSG, whereas the resolidified sample showed the broad transition due to solidified liquid phases.

Materials for Heated Head Automated Thermoplastic Tape Placement

NASA Technical Reports Server (NTRS)

Jensen, Brian J.; Kinney, Megan C.; Cano, Roberto J.; Grimsley, Brian W.

2012-01-01

NASA Langley Research Center (LaRC) is currently pursuing multiple paths to develop out of autoclave (OOA) polymeric composite materials and processes. Polymeric composite materials development includes the synthesis of new and/or modified thermosetting and thermoplastic matrix resins designed for specific OOA processes. OOA processes currently under investigation include vacuum bag only (VBO) prepreg/composite fabrication, resin transfer molding (RTM), vacuum assisted resin transfer molding (VARTM) and heated head automated thermoplastic tape placement (HHATP). This paper will discuss the NASA Langley HHATP facility and capabilities and recent work on characterizing thermoplastic tape quality and requirements for quality part production. Samples of three distinct versions of APC-2 (AS4/PEEK) thermoplastic dry tape were obtained from two materials vendors, TENCATE, Inc. and CYTEC Engineered Materials** (standard grade and an experimental batch). Random specimens were taken from each of these samples and subjected to photo-microscopy and surface profilometry. The CYTEC standard grade of APC-2 tape had the most voids and splits and the highest surface roughness and/or waviness. Since the APC-2 tape is composed of a thermoplastic matrix, it offers the flexibility of reprocessing to improve quality, and thereby improve final quality of HHATP laminates. Discussions will also include potential research areas and future work that is required to advance the state of the art in the HHATP process for composite fabrication.

The OCLC-SERHOLD connection: an evolution in health sciences union listing.

PubMed Central

Battistella, M S

1991-01-01

The OCLC Union List Subsystem (OCLC ULS) provides a standard, high quality, and widely used means of managing union list data. Over the last several years, OCLC ULS tape products have been used by thirteen health sciences libraries or groups to update SERHOLD. These thirteen libraries or groups were surveyed to examine practices in using OCLC to update SERHOLD. The National Library of Medicine's (NLM) processing of OCLC tape products was assessed to determine how OCLC data are handled by SERHOLD. Most important are the assignment of OCLC holdings symbols, OCLC record selection criteria, tape pull cycles, and the processing of exception reports produced by NLM as a result of tape loads. PMID:1958909

The OCLC-SERHOLD connection: an evolution in health sciences union listing.

PubMed

Battistella, M S

1991-10-01

The OCLC Union List Subsystem (OCLC ULS) provides a standard, high quality, and widely used means of managing union list data. Over the last several years, OCLC ULS tape products have been used by thirteen health sciences libraries or groups to update SERHOLD. These thirteen libraries or groups were surveyed to examine practices in using OCLC to update SERHOLD. The National Library of Medicine's (NLM) processing of OCLC tape products was assessed to determine how OCLC data are handled by SERHOLD. Most important are the assignment of OCLC holdings symbols, OCLC record selection criteria, tape pull cycles, and the processing of exception reports produced by NLM as a result of tape loads.

Preparation and Characterization of High Temperature Superconductor Film Surfaces

DTIC Science & Technology

1993-10-27

Lanthanum Strontium Copper Oxide (LSCO) was also tested as a normal metal overlayer because of its compatibility with the high deposition temperature for...fabricate YBCO/ISCO SEB junctions using a variety of step heights (110 nm - 330 nm) on Neodymium Gallate (NGO) substrates. NGO was chosen as a...substrate because of its excellent lattice match to YBCO and its lack of crystal twinning Twinning had been a drawback of Lanthanum Aluminate (LAO)- L

The Effects of Grain Boundaries on the Current Transport Properties in YBCO-Coated Conductors

NASA Astrophysics Data System (ADS)

Yang, Chao; Xia, Yudong; Xue, Yan; Zhang, Fei; Tao, Bowan; Xiong, Jie

2015-10-01

We report a detailed study of the grain orientations and grain boundary (GB) networks in Y2O3 films grown on Ni-5 at.%W substrates. Electron back scatter diffraction (EBSD) exhibited different GB misorientation angle distributions, strongly decided by Y2O3 films with different textures. The subsequent yttria-stabilized zirconia (YSZ) barrier and CeO2 cap layer were deposited on Y2O3 layers by radio frequency sputtering, and YBa2Cu3O7-δ (YBCO) films were deposited by pulsed laser deposition. For explicating the effects of the grain boundaries on the current carry capacity of YBCO films, a percolation model was proposed to calculate the critical current density ( J c) which depended on different GB misorientation angle distributions. The significantly higher J c for the sample with sharper texture is believed to be attributed to improved GB misorientation angle distributions.

La0.7Sr0.3MnO3: A single, conductive-oxide buffer layer for the development of YBa2Cu3O7-δ coated conductors

NASA Astrophysics Data System (ADS)

Aytug, T.; Paranthaman, M.; Kang, B. W.; Sathyamurthy, S.; Goyal, A.; Christen, D. K.

2001-10-01

Coated conductor applications in power technologies require stabilization of the high-temperature superconducting (HTS) layers against thermal runaway. Conductive La0.7Sr0.3MnO3 (LSMO) has been epitaxially grown on biaxially textured Ni substrates as a single buffer layer. The subsequent epitaxial growth of YBa2Cu3O7-δ (YBCO) coatings by pulsed laser deposition yielded self-field critical current densities (Jc) of 0.5×106A/cm2 at 77 K, and provided good electrical connectivity over the entire structure (HTS+conductive-buffer+metal substrate). Property characterizations of YBCO/LSMO/Ni architecture revealed excellent crystallographic and morphological properties. These results have demonstrated that LSMO, used as a single, conductive buffer layer, may offer potential for use in fully stabilized YBCO coated conductors.

106 17 Telemetry Standards Annex A.2 Magnetic Tape Recorder and Reproducer Information and Use Criteria

DTIC Science & Technology

2017-07-31

Telemetry Standards, IRIG Standard 106-17 Annex A.2, May 2017 ANNEX A.2 Magnetic Tape Recorder and Reproducer Information and Use Criteria...Annex A.2, May 2017 A.2-1 ANNEX A.2 Magnetic Tape Recorder and Reproducer Information and Use Criteria 1. Other Instrumentation Magnetic Tape...http://webstore.ansi.org). Documentation applicable to this annex is identified in the following bullets. • ISO 1860 (1986), Information Processing

LANDSAT-D data format control book. Volume 6, appendix C: Partially processed multispectral scanner high density tape (HDT-AM)

NASA Technical Reports Server (NTRS)

Andersen, K. E.

1982-01-01

The format of high density tapes which contain partially processed LANDSAT 4 and LANDSAT D prime MSS image data is defined. This format is based on and is compatible with the existing format for partially processed LANDSAT 3 MSS image data HDTs.

The Composing Processes of Unskilled Writers at the College Level.

ERIC Educational Resources Information Center

Perl, Sondra

This paper uses five case studies of unskilled writers at the college level to provide insights into the composing process. Each student's writing process was tape-recorded and observed by the instructor in four sessions. The tapes and written observations were charted and analyzed for exhibited behavior patterns in comparison to the written…

High-performance superconductors for Fusion Nuclear Science Facility

DOE PAGES

Zhai, Yuhu; Kessel, Chuck; Barth, Christian; ...

2016-11-09

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

High-performance superconductors for Fusion Nuclear Science Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhai, Yuhu; Kessel, Chuck; Barth, Christian

High-performance superconducting magnets play an important role in the design of the next step large-scale, high-field fusion reactors such as the fusion nuclear science facility (FNSF) and the spherical tokamak (ST) pilot plant beyond ITER. Here, Princeton Plasma Physics Laboratory is currently leading the design studies of the FNSF and the ST pilot plant study. ITER, which is under construction in the south of France, utilizes the state-of-the-art low temperature superconducting magnet technology based on the cable-in-conduit conductor design, where over a thousand multifilament Nb 3Sn superconducting strands are twisted together to form a high-current-carrying cable inserted into a steelmore » jacket for coil windings. We present design options of the high-performance superconductors in the winding pack for the FNSF toroidal field magnet system based on the toroidal field radial build from the system code. For the low temperature superconductor options, the advanced J cNb 3Sn RRP strands (J c > 1000 A/mm 2 at 16 T, 4 K) from Oxford Superconducting Technology are under consideration. For the high-temperature superconductor options, the rectangular-shaped high-current HTS cable made of stacked YBCO tapes will be considered to validate feasibility of TF coil winding pack design for the ST-FNSF magnets.« less

Operating characteristics of superconducting fault current limiter using 24kV vacuum interrupter driven by electromagnetic repulsion switch

NASA Astrophysics Data System (ADS)

Endo, M.; Hori, T.; Koyama, K.; Yamaguchi, I.; Arai, K.; Kaiho, K.; Yanabu, S.

2008-02-01

Using a high temperature superconductor, we constructed and tested a model Superconducting Fault Current Limiter (SFCL). SFCL which has a vacuum interrupter with electromagnetic repulsion mechanism. We set out to construct high voltage class SFCL. We produced the electromagnetic repulsion switch equipped with a 24kV vacuum interrupter(VI). There are problems that opening speed becomes late. Because the larger vacuum interrupter the heavier weight of its contact. For this reason, the current which flows in a superconductor may be unable to be interrupted within a half cycles of current. In order to solve this problem, it is necessary to change the design of the coil connected in parallel and to strengthen the electromagnetic repulsion force at the time of opening the vacuum interrupter. Then, the design of the coil was changed, and in order to examine whether the problem is solvable, the current limiting test was conducted. We examined current limiting test using 4 series and 2 parallel-connected YBCO thin films. We used 12-centimeter-long YBCO thin film. The parallel resistance (0.1Ω) is connected with each YBCO thin film. As a result, we succeed in interrupting the current of superconductor within a half cycle of it. Furthermore, series and parallel-connected YBCO thin film could limit without failure.

Observation of Sinusoidal Voltage Behaviour in Silver Doped YBCO

NASA Astrophysics Data System (ADS)

Altinkok, Atilgan; Olutas, Murat; Kilic, Kivilcim; Kilic, Atilla

The influence of bi-directional square wave (BSW) current was investigated on the evolution of the V - t curves at different periods (P) , temperatures and external magnetic fields. It was observed that slow transport relaxation measurements result in regular sinusoidal voltage oscillations which were discussed mainly in terms of the dynamic competition between pinning and depinning.The symmetry in the voltage oscillations was attributed to the elastic coupling between the flux lines and the pinning centers along grain boundaries and partly inside the grains. This case was also correlated to the equality between flux entry and exit along the YBCO/Ag sample during regular oscillations. It was shown that the voltage oscillations can be described well by an empirical expression V (t) sin(wt + φ) . We found that the phase angle φgenerally takes different values for the repetitive oscillations. Fast Fourier Transform analysis of the V - t oscillations showed that the oscillation period is comparable to that (PI) of the BSW current. This finding suggests a physical mechanism associated with charge density waves (CDWs), and, indeed, the weakly pinned flux line system in YBCO/Ag resembles the general behavior of CDWs. At certain values of PI, amplitude of BSW current, H and T, the YBCO/Ag sample behaves like a double-integrator, since it converts the BSW current to sinusoidal voltage oscillations in time.

Improvements of fabrication processes and enhancement of critical current densities in (Ba,K)Fe2As2 HIP wires and tapes

NASA Astrophysics Data System (ADS)

Pyon, Sunseng; Suwa, Takahiro; Tamegai, Tsuyoshi; Takano, Katsutoshi; Kajitani, Hideki; Koizumi, Norikiyo; Awaji, Satoshi; Zhou, Nan; Shi, Zhixiang

2018-05-01

We fabricated (Ba,K)Fe2As2 superconducting wires and tapes using the powder-in-tube method and hot isostatic pressing (HIP). HIP wires and tapes showed a high value of transport critical current density (J c) exceeding 100 kAcm‑2 at T = 4.2 K and the self-field. Transport J c in the HIP wire reached 38 kAcm‑2 in a high magnetic field of 100 kOe. This value is almost twice larger than the previous highest value of J c among round wires using iron-based superconductors. Enhancement of J c in the wires and tapes was caused by improvement of the drawing process, which caused degradation of the core, formation of microcracks, weak links between grains, and random orientation of grains. Details of the effect of the improved fabrication processes on the J c are discussed.

Method and apparatus for data decoding and processing

DOEpatents

Hunter, Timothy M.; Levy, Arthur J.

1992-01-01

A system and technique is disclosed for automatically controlling the decoding and digitizaiton of an analog tape. The system includes the use of a tape data format which includes a plurality of digital codes recorded on the analog tape in a predetermined proximity to a period of recorded analog data. The codes associated with each period of analog data include digital identification codes prior to the analog data, a start of data code coincident with the analog data recording, and an end of data code subsequent to the associated period of recorded analog data. The formatted tape is decoded in a processing and digitization system which includes an analog tape player coupled to a digitizer to transmit analog information from the recorded tape over at least one channel to the digitizer. At the same time, the tape player is coupled to a decoder and interface system which detects and decodes the digital codes on the tape corresponding to each period of recorded analog data and controls tape movement and digitizer initiation in response to preprogramed modes. A host computer is also coupled to the decoder and interface system and the digitizer and programmed to initiate specific modes of data decoding through the decoder and interface system including the automatic compilation and storage of digital identification information and digitized data for the period of recorded analog data corresponding to the digital identification data, compilation and storage of selected digitized data representing periods of recorded analog data, and compilation of digital identification information related to each of the periods of recorded analog data.

Fast infrared response of YBCO thin films

NASA Technical Reports Server (NTRS)

Ballentine, P. H.; Kadin, A. M.; Donaldson, W. R.; Scofield, J. H.; Bajuk, L.

1990-01-01

The response to short infrared pulses of some epitaxial YBCO films prepared by sputter deposition and by electron-beam evaporation is reported. The response is found to be essentially bolometric on the ns timescale, with some indirect hints of nonequilibrium electron transport on the ps scale. Fast switching could be obtained either by biasing the switch close to the critical current or by cooling the film below about 20 K. These results are encouraging for potential application to a high-current optically-triggered opening switch.

Performance prediction of high Tc superconducting small antennas using a two-fluid-moment method model

NASA Astrophysics Data System (ADS)

Cook, G. G.; Khamas, S. K.; Kingsley, S. P.; Woods, R. C.

1992-01-01

The radar cross section and Q factors of electrically small dipole and loop antennas made with a YBCO high Tc superconductor are predicted using a two-fluid-moment method model, in order to determine the effects of finite conductivity on the performances of such antennas. The results compare the useful operating bandwidths of YBCO antennas exhibiting varying degrees of impurity with their copper counterparts at 77 K, showing a linear relationship between bandwidth and impurity level.

Effect of the microscopic correlated-pinning landscape on the macroscopic critical current density in YBCO films

NASA Astrophysics Data System (ADS)

Ghigo, G.; Chiodoni, A.; Gerbaldo, R.; Gozzelino, L.; Laviano, F.; Mezzetti, E.; Minetti, B.; Camerlingo, C.

This paper deals with the mechanisms controlling the critical current density vs. field behavior in YBCO films. We base our analysis on a suitable model concerning the existence of a network of intergrain Josephson junctions whose length is modulated by defects. Irradiation with 0.25 GeV Au ions provide a useful tool to check the texture of the sample, in particular to give a gauge length reference to separate “weak” links and high- J c links.

Protecting Superconducting HTS-Antennas by Meta-Material Cloaks

DTIC Science & Technology

2014-04-30

radiation efficiency for this antenna is 22.3\\%. However, if the normal conducting part is replaced with a superconductor , e.g. YBCO with RS=500µΩ, [8] the...loss resistance can be brought down due to the much lower surface resistance of the superconductor relative to the normal conductor. Chalupka et al...range [12]. In 1987, Wu et al. [13] discovered the HTS compound YBCO that has a TC of ≈ 92K, which was the first superconductor to have a TC greater

Process for forming epitaxial perovskite thin film layers using halide precursors

DOEpatents

Clem, Paul G.; Rodriguez, Mark A.; Voigt, James A.; Ashley, Carol S.

2001-01-01

A process for forming an epitaxial perovskite-phase thin film on a substrate. This thin film can act as a buffer layer between a Ni substrate and a YBa.sub.2 Cu.sub.3 O.sub.7-x superconductor layer. The process utilizes alkali or alkaline metal acetates dissolved in halogenated organic acid along with titanium isopropoxide to dip or spin-coat the substrate which is then heated to about 700.degree. C. in an inert gas atmosphere to form the epitaxial film on the substrate. The YBCO superconductor can then be deposited on the layer formed by this invention.

High-Pressure Oxygenation of Mt-Ybco the way to Reduce the Oxygenation Time, to Prevent Macrocracking, and to Obtain Materials with High Critical Currents.

NASA Astrophysics Data System (ADS)

Prikhna, T. A.; Chaud, X.; Gawalek, W.; Joulain, A.; Rabier, J.; Moshchil, V. E.; Savchuk, Ya. M.; Sergienko, N. V.; Dub, S. N.; Melnikov, V. S.; Habisreuther, T.; Litzkendorf, D.; Bierlich, J.

2008-03-01

The oxygenation of MT-YBCO under isostatic oxygen pressure (up to 16 MPa) at 900-800 °C allowed reduced process time, lower macrocracking, and reduced microcracks. Additionally higher critical currents, trapped fields and mechanical characteristics can be attained. At 77 K thin-walled MT-YBCO had a jc in the ab plane of 85 kA/cm2 at 0 T and higher than 10 kA/cm2 in fields up to 5 T and the irreversibility field was 9.8 T. In the c-direction jc was 34 kA/cm2 in 0 T and higher than 2.5 kA/cm2 in a 10 T field. At 4.9 N-load the micohardness, Hv, was 8.7±0.3 GPa in the ab-plane and 7.6±0.3 GPa in the c-direction. The fracture toughness, K1C, was 2.5±0.1 MPaṡm0.5 (ab-plane) and 2.8±0.24 MPaṡm0.5 (c-direction). The samples with a higher twin density demonstrated a higher jc, especially in applied magnetic field. The twin density correlates with the sizes and distribution of Y211 grains in Y123. The thin-walled ceramics that demonstrated the highest jc contained about 22 twins in 1 μm and were practically free from dislocations and stacking faults. The maximal trapped field of the block of thin-walled ceramic oxygenated at 900-800 °C and 16 MPa was doubled as compared to that oxygenated at low temperature under ambient pressure.

Manual on characteristics of Landsat computer-compatible tapes produced by the EROS Data Center digital image processing system

USGS Publications Warehouse

Holkenbrink, Patrick F.

1978-01-01

Landsat data are received by National Aeronautics and Space Administration (NASA) tracking stations and converted into digital form on high-density tapes (HDTs) by the Image Processing Facility (IPF) at the Goddard Space Flight Center (GSFC), Greenbelt, Maryland. The HDTs are shipped to the EROS Data Center (EDC) where they are converted into customer products by the EROS Data Center digital image processing system (EDIPS). This document describes in detail one of these products: the computer-compatible tape (CCT) produced from Landsat-1, -2, and -3 multispectral scanner (MSS) data and Landsat-3 only return-beam vidicon (RBV) data. Landsat-1 and -2 RBV data will not be processed by IPF/EDIPS to CCT format.

Process of Making Boron-Fiber Reinforced Composite Tape

NASA Technical Reports Server (NTRS)

Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor); Johnston, Norman J. (Inventor); Marchello, Joseph M. (Inventor)

2002-01-01

The invention is an apparatus and method for producing a hybrid boron reinforced polymer matrix composition from powder pre-impregnated fiber tow bundles and a linear array of boron fibers. The boron fibers are applied onto the powder pre-impregnated fiber tow bundles and then are processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the powder pre-impregnated fiber tow bundles with the boron fibers become a hybrid boron reinforced polymer matrix composite tape. A driving mechanism pulls the powder pre-impregnated fiber tow bundles with boron fibers through the processing line of the apparatus and a take-up spool collects the formed hybrid boron-fiber reinforced polymer matrix composite tape.

Roles of Poly(propylene Glycol) During Solvent-Based Lamination of Ceramic Green Tapes

NASA Technical Reports Server (NTRS)

Suppakarn, Nitinat; Ishida, Hatsuo; Cawley, James D.; Levine, Stanley R. (Technical Monitor)

2000-01-01

Solvent lamination for alumina green tapes is readily accomplished using a mixture of ethanol, toluene and poly(propylene glycol). After lamination, the PPG is clearly present as a discrete film at the interface between the laminated tapes. This condition, however, does not generate delamination during firing. Systematic sets of experiments are undertaken to determine the role of PPG in the lamination process and, specifically, the mechanism by which it is redistributed during subsequent processing. PPG slowly diffuses through the organic binder film at room temperature. The PPG diffusion rapidly increases as temperature is increased to 80 C. The key to the efficiency of adhesives during green-tape lamination is mutual solubility of the nonvolatile component of the glue and the base polymeric binder.

Environmentally benign processing of YAG transparent wafers

NASA Astrophysics Data System (ADS)

Yang, Yan; Wu, Yiquan

2015-12-01

Transparent yttrium aluminum garnet (YAG) wafers were successfully produced via aqueous tape casting and vacuum sintering techniques using a new environmentally friendly binder, a copolymer of isobutylene and maleic anhydride with the commercial name ISOBAM (noted as ISOBAM). Aqueous YAG slurries were mixed by ball-milling, which was followed by de-gassing and tape casting of wafers. The final YAG green tapes were homogenous and flexible, and could be bent freely without cracking. After the drying and sintering processes, transparent YAG wafers were achieved. The microstructures of both the green tape and vacuum-sintered YAG ceramic were observed by scanning electronic microscopy (SEM). Phase compositions were examined by X-ray diffraction (XRD). Optical transmittance was measured in UV-VIS regions with the result that the transmittance is 82.6% at a wavelength of 800 nm.

Processing and property evaluation of metal matrix superconducting materials

NASA Technical Reports Server (NTRS)

Rao, Appajosula S.

1995-01-01

Metal - superconductor (YBCO) systems have been prepared and characterized by resistivity, ac susceptibility and dc SQUID magnetic moment measurements. The silver composites showed superconducting transition for all the composites processed and the superconducting transition temperature tends to depend upon the concentration of the silver in the composite. Aluminum composites showed an unusual resistivity results with two transitions around 90 K and 120 K. The superconducting property of silver composites can be explained qualitatively in terms of the proximity theory that has been suggested for the low temperature superconductors.

Static Test for a Gravitational Force Coupled to Type 2 YBCO Superconductors

NASA Technical Reports Server (NTRS)

Li, Ning; Noever, David; Robertson, Tony; Koczor, Ron; Brantley, Whitt

1997-01-01

As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (approx. 10(exp -6) g cc. Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating type II, YBCO superconductor, with the percentage change (0.05 - 2.1 %) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 10' was reported above a stationary (non-rotating) superconductor. In experiments using a sensitive gravimeter, bulk YBCO superconductors were stably levitated in a DC magnetic field. Changes in acceleration were measured to be less than 2 parts in 108 of the normal gravitational acceleration. This result puts new limits on the strength and range of the proposed coupling between static superconductors and gravity.

Effects of K and Ca doping on twin boundary energy of cupperate superconductors

NASA Astrophysics Data System (ADS)

Khoshnevisan, Bahram; Mohammadi, Mahnaz

2016-04-01

Ab-initio calculations under GGA approximation have been employed to find out the effect Ba substitution by K and Ca on the structural and electronic properties twined and untwined YBCO system. In this regard, the twin boundary energy, γ, and impact of the substitution on the boundary's charge distribution have been of special consideration. Our results show that despite the structural changes the presence of K (Ca) modifies substantially density of levels at the Fermi level, which could be responsible for empirical reports of decreasing the critical temperature (Tc) by increasing the K(Ca) content. Although, the K doping reduces the γ value in YBa2-xKxCu3O7 system, after calcium doping it remains more or less unchanged. In addition, reduction of the carrier density occurs at twin boundary in CuO2 layer for the substituted system with respect to the untwined YBCO system. Our results would be noticeable in conjunction with the experimentally reported twinned and alkali substituted superconductive properties of the YBCO samples.

Vortex Flux Pinning in Type-Ii Superconductors

NASA Astrophysics Data System (ADS)

Hasan, Mohammad-Khair A. M.

1995-01-01

Rotational magnetization vector measurements on polycrystalline samples of rm YBa_2Cu _3O_7 (YBCO) and (Ba, K)BiO _3 at various fixed fields (H) and temperatures (T) reveal that the vortex flux density (B) in a rotational state consists of a component B_{rm R}, which rotates rigidly with sample rotation, and a B_{rm F} component, which stays at a fixed frictional angle (theta _{rm F}) relative to H. Also, B_{rm R} decreases and ultimately vanishes with increasing H, while B _{rm F} grows monotonically, implying that the vortex pinning strength have a broad distribution. This has been confirmed by the measurements on YBCO of the remanent flux density B^ {rm rm} which can be decomposed analogously into B_{R} ^{} and B_ {F}^{} at angle theta_{F}^{} relative to H. The quantity Hsin theta_{rm F},, which at equilibrium equals tau_{rm p}/mu (the average pinning torque per vortex of moment mu) decreases with increasing high H. This result and the distribution in the strength of the pinning are shown to be consistent with the collective pinning process of vortex bundling. At fixed H, tau_{rm p} decreases rapidly with increasing T, varying approximately as T^{-0.8} for both samples. For polycrystalline YBCO at 4.2 K, B_ {rm R} and B_{ rm F} are found to relax differently with time. The negative creep sign of B_ {rm R} indicates that the number of rotational vortices decreases with time, whereas B _{rm F} shows a positive creep with a negative change in theta_ {rm F}, which indicates that more frictional vortices enter the sample with a tendency of alignment in the direction of H. For grain-oriented YBCO at 4.2 K, the vortex creep measurements of B along the c-axis at different fields showed that: whenever the hysteretic changes of H are reversed in sign, the vortex flux creep (dB/dlogt) decreases very rapidly to zero, where it lingers before changing sign. At the same turning values of H, (dB/dH) also goes to zero. These properties are attributable to the reversals of the vortex motion which occur at the turning values of H and cause a reversal of frictional pinning forces.

Property and microstructural nonuniformity in the yttrium-barium-copper-oxide superconductor determined from electrical, magnetic, and ultrasonic measurements. Ph.D. Thesis - Case Western Reserve Univ.

NASA Technical Reports Server (NTRS)

Roth, Don J.

1991-01-01

The purpose of this dissertation was the following: (1) to characterize the effect of pore fraction on a comprehensive set of electrical and magnetic properties for the yttrium-barium-copper-oxide (YBCO) high temperature ceramic superconductor; and (2) to determine the viability of using a room-temperature, nondestructive characterization method to aid in the prediction of superconducting (cryogenic) properties. The latter involved correlating ultrasonic velocity measurements at room temperature with property-affecting pore fraction and oxygen content variations. The use of ultrasonic velocity for estimating pore fraction in YBCO is presented, and other polycrystalline materials are reviewed, modeled, and statistically analyzed. This provides the basis for using ultrasonic velocity to interrogate microstructure. The effect of pore fraction (0.10-0.25) on superconductor properties of YBCO samples was characterized. Spatial (within-sample) variations in microstructure and superconductor properties were investigated, and the effect of oxygen content on elastic behavior was examined. Experimental methods used included a.c. susceptibility, electrical, and ultrasonic velocity measurements. Superconductor properties measured included transition temperature, magnetic transition width, transport and magnetic critical current density, magnetic shielding, a.c. loss, and sharpness of the voltage-current characteristics. An ultrasonic velocity image constructed from measurements at 1mm increments across a YBCO sample revealed microstructural variations that correlated with variations in magnetic shielding and a.c. loss behavior. Destructive examination using quantitative image analysis revealed pore fraction to be the varying microstructural feature.

Visualization of latent fingerprints beneath opaque electrical tapes by optical coherence tomography

NASA Astrophysics Data System (ADS)

Liu, Kangkang; Zhang, Ning; Meng, Li; Li, Zhigang; Xu, Xiaojing

2018-03-01

Electrical tape is found as one type of important trace evidence in crime scene. For example, it is very frequently used to insulate wires in explosive devices in many criminal cases. The fingerprints of the suspects were often left on the adhesive side of the tapes, which can provide very useful clues for the investigation and make it possible for individual identification. The most commonly used method to detect and visualize those latent fingerprints is to peel off each layer of the tapes first and then adopt the chemical methods to develop the fingerprints on the tapes. However, the peeling-off and chemical development process would degrade and contaminate the fingerprints and thus adversely affect the accuracy of identification. Optical coherence tomography (OCT) is a novel forensic imaging modality based on lowcoherence interferometry, which has the advantages of non-destruction, micrometer-level high resolution and crosssectional imaging. In this study, a fiber-based spectral-domain OCT (SD-OCT) system with {6μm resolution was employed to obtain the image of fingerprint sandwiched between two opaque electrical tapes without any pre-processing procedure like peeling-off. Three-dimensional (3D) OCT reconstruction was performed and the subsurface image was produced to visualize the latent fingerprints. The results demonstrate that OCT is a promising tool for recovering the latent fingerprints hidden beneath opaque electrical tape non-destructively and rapidly.

Flywheel energy storage with superconductor magnetic bearings

DOEpatents

Weinberger, Bernard R.; Lynds, Jr., Lahmer; Hull, John R.

1993-01-01

A flywheel having superconductor bearings has a lower drag to lift ratio that translates to an improvement of a factor of ten in the rotational decay rate. The lower drag results from the lower dissipation of melt-processed YBCO, improved uniformity of the permanent magnet portion of the bearings, operation in a different range of vacuum pressure from that taught by the art, and greater separation distance from the rotating members of conductive materials.

A tape recorder as a therapeutic "witness" in the treatment of an 8-year-old girl.

PubMed

Tuber, Steven; Seckin, Banu

2012-11-01

A tape-recorded session of an early moment in an 8-year-old girl's psychotherapy experience is presented. The use of the recording device is immediately taken up by the child as a means of creating a "witness" for her depiction of both intensely distorted experiences of her therapist and poignant portrayals of her life as miserable and despairing. A discussion of both the process and the content generated from the use of the tape recorder is described, with implications drawn as to its effectiveness in the therapeutic process. © 2012 Wiley Periodicals, Inc.

Field spectrometer (S191H) preprocessor tape quality test program design document

NASA Technical Reports Server (NTRS)

Campbell, H. M.

1976-01-01

Program QA191H performs quality assurance tests on field spectrometer data recorded on 9-track magnetic tape. The quality testing involves the comparison of key housekeeping and data parameters with historic and predetermined tolerance limits. Samples of key parameters are processed during the calibration period and wavelength cal period, and the results are printed out and recorded on an historical file tape.

Implementation and extension of the impulse transfer function method for future application to the space shuttle project. Volume 2: Program description and user's guide

NASA Technical Reports Server (NTRS)

Patterson, G.

1973-01-01

The data processing procedures and the computer programs were developed to predict structural responses using the Impulse Transfer Function (ITF) method. There are three major steps in the process: (1) analog-to-digital (A-D) conversion of the test data to produce Phase I digital tapes (2) processing of the Phase I digital tapes to extract ITF's and storing them in a permanent data bank, and (3) predicting structural responses to a set of applied loads. The analog to digital conversion is performed by a standard package which will be described later in terms of the contents of the resulting Phase I digital tape. Two separate computer programs have been developed to perform the digital processing.

Influence of technology on magnetic tape storage device characteristics

NASA Technical Reports Server (NTRS)

Gniewek, John J.; Vogel, Stephen M.

1994-01-01

There are available today many data storage devices that serve the diverse application requirements of the consumer, professional entertainment, and computer data processing industries. Storage technologies include semiconductors, several varieties of optical disk, optical tape, magnetic disk, and many varieties of magnetic tape. In some cases, devices are developed with specific characteristics to meet specification requirements. In other cases, an existing storage device is modified and adapted to a different application. For magnetic tape storage devices, examples of the former case are 3480/3490 and QIC device types developed for the high end and low end segments of the data processing industry respectively, VHS, Beta, and 8 mm formats developed for consumer video applications, and D-1, D-2, D-3 formats developed for professional video applications. Examples of modified and adapted devices include 4 mm, 8 mm, 12.7 mm and 19 mm computer data storage devices derived from consumer and professional audio and video applications. With the conversion of the consumer and professional entertainment industries from analog to digital storage and signal processing, there have been increasing references to the 'convergence' of the computer data processing and entertainment industry technologies. There has yet to be seen, however, any evidence of convergence of data storage device types. There are several reasons for this. The diversity of application requirements results in varying degrees of importance for each of the tape storage characteristics.

Electron-positron momentum distribution measurements of high-T superconductors and related systems

NASA Astrophysics Data System (ADS)

Wachs, A. L.; Turchi, P. E. A.; Howell, R. J.; Jean, Y. C.; Fluss, M. J.; West, R. N.; Kaiser, J. H.; Rayner, S.; Hahgighi, H.; Merkle, K. L.

1989-08-01

Measurements are discussed of the 2-D angular correlation of positron annihilation radiation (ACAR) in La2CuO4, YBa2Cu3O7 (YBCO), and NiO. The measurements for NiO are the first such 2-D ACAR measurements; the YBCO results are of a higher statistical quality than previously reported in the literature. The data are compared with complementary theoretical calculations and with each other. The implication is discussed of the analysis for ACAR studies of similar and related systems.

Electron-position momentum distribution measurements of high-T c superconductors and related systems

NASA Astrophysics Data System (ADS)

Wachs, A. L.; Turchi, P. E. A.; Howell, R. H.; Jean, Y. C.; Fluss, M. J.; West, R. N.; Kaiser, J. H.; Rayner, S.; Haghighi, H.; Merkle, K. L.; Revcolevschi, A.; Wang, Z. Z.

1989-12-01

We discuss our measurements of the 2D-angular correlation of positron annihilation radiation (ACAR) in La 2CuO 4, YBa 2Cu 3O 7 (YBCO), and NiO. The measurements for NiO are the first such 2D-ACAR measurements; the YBCO results are of a higher statistical quality than previously reported in the literature. The data are compared with complementary theoretical calculations and with each other. We discuss the implication of our analysis for ACAR studies of similar and related systems.

Fabrication of high edge-definition steel-tape gratings for optical encoders.

PubMed

Ye, Guoyong; Liu, Hongzhong; Yan, Jiawei; Ban, Yaowen; Fan, Shanjin; Shi, Yongsheng; Yin, Lei

2017-10-01

High edge definition of a scale grating is the basic prerequisite for high measurement accuracy of optical encoders. This paper presents a novel fabrication method of steel tape gratings using graphene oxide nanoparticles as anti-reflective grating strips. Roll-to-roll nanoimprint lithography is adopted to manufacture the steel tape with hydrophobic and hydrophilic pattern arrays. Self-assembly technology is employed to obtain anti-reflective grating strips by depositing the graphene oxide nanoparticles on hydrophobic regions. A thin SiO 2 coating is deposited on the grating to protect the grating strips. Experimental results confirm that the proposed fabrication process enables a higher edge definition in making steel-tape gratings, and the new steel tape gratings offer better performance than conventional gratings.

Fabrication of high edge-definition steel-tape gratings for optical encoders

NASA Astrophysics Data System (ADS)

Ye, Guoyong; Liu, Hongzhong; Yan, Jiawei; Ban, Yaowen; Fan, Shanjin; Shi, Yongsheng; Yin, Lei

2017-10-01

High edge definition of a scale grating is the basic prerequisite for high measurement accuracy of optical encoders. This paper presents a novel fabrication method of steel tape gratings using graphene oxide nanoparticles as anti-reflective grating strips. Roll-to-roll nanoimprint lithography is adopted to manufacture the steel tape with hydrophobic and hydrophilic pattern arrays. Self-assembly technology is employed to obtain anti-reflective grating strips by depositing the graphene oxide nanoparticles on hydrophobic regions. A thin SiO2 coating is deposited on the grating to protect the grating strips. Experimental results confirm that the proposed fabrication process enables a higher edge definition in making steel-tape gratings, and the new steel tape gratings offer better performance than conventional gratings.

SAGE 1 data user's guide

NASA Technical Reports Server (NTRS)

Mcmaster, Leonard R.; Chu, William P.; Rowland, Michael W.

1992-01-01

A guide for using the data products from the Stratospheric Aerosol and Gas Experiment 1 (SAGE 1) for scientific investigations of stratospheric chemistry related to aerosol, ozone, nitrogen dioxide, dynamics, and climate change is presented. A detailed description of the aerosol profile tape, the ozone profile tape, and the nitrogen dioxide profile tape is included. These tapes are the SAGE 1 data products containing aerosol extinction data and ozone and nitrogen dioxide concentration data for use in the different scientific investigations. Brief descriptions of the instrument operation, data collection, processing, and validation, and some of the scientific analyses that were conducted are also included.

That Elusive, Eclectic Thing Called Thermal Environment: What a Board Should Know About It

ERIC Educational Resources Information Center

Schutte, Frederick

1970-01-01

Discussion of proper thermal environment for protection of sophisticated educational equipment such as computer and data-processing machines, magnetic tapes, closed-circuit television and video tape communications systems.

Make Development Decisions Predictable and Fair: Green Tape Program, Silver Spring, Maryland

EPA Pesticide Factsheets

Montgomery County's Green Tape program is making redevelopment in Silver Spring, Maryland, faster and more cost effective by speeding the permitting process for development in the mixed-use city center.

Interface control document between the NASA Goddard Space Flight Center (GSFC) and Department of Interior EROS Data Center (EDC) for LANDSAT-D. Partially processed multispectral scanner High Density Tape (HDT-AM)

NASA Technical Reports Server (NTRS)

1982-01-01

The format of the HDT-AM product which contains partially processed LANDSAT D and D Prime multispectral scanner image data is defined. Recorded-data formats, tape format, and major frame types are described.

Spherical harmonic representation of the main geomagnetic field for world charting and investigations of some fundamental problems of physics and geophysics

NASA Technical Reports Server (NTRS)

Barraclough, D. R.; Hide, R.; Leaton, B. R.; Lowes, F. J.; Malin, S. R. C.; Wilson, R. L. (Principal Investigator)

1981-01-01

The data processing of MAGSAT investigator B test tapes and data tapes, and tapes of selected data on 15 magnetically quiet days is reported. The 1980 World Chart spherical model was compared with the MAGSAT (3/80) and MAGSAT vector data were used in the models. An article on modelling the geomagnetic field using satellite data is included.

Enhanced Data-Acquisition System

NASA Technical Reports Server (NTRS)

Mustain, Roy W.

1990-01-01

Time-consuming, costly digitization of analog signals on magnetic tape eliminated. Proposed data-acquisition system provides nearly immediate access to data in incoming signals by digitizing and recording them both on magnetic tape and on optical disk. Tape and/or disk later played back to reconstruct signals in analog or digital form for analysis. Of interest in industrial and scientific applications in which necessary to digitize, store, and/or process large quantities of experimental data.

Studies of anisotropic in-plane aligned a-axis oriented YBa(2)Cu(3)O(7-x) thin films

NASA Astrophysics Data System (ADS)

Trajanovic, Zoran

1997-12-01

Due to their layered planar structure, cuprate oxide superconductors possess remarkable anisotropic properties which may be related to their high transition temperatures. In-plane aligned a-axis YBa2Cu3O7 (YBCO) films are good candidates for such anisotropic studies. Furthermore, the full advantage of favorable material characteristics can be then utilized in applications such as vertical SNS junctions with the leads along the b-direction of YBCO and other novel junction configurations. High quality, smooth, in-plane aligned films are obtained on (100) LaSrGaO4. Form x-ray data, the films show complete b- and c-axes separation for the measured a-axis orientation. The anisotropic resistivity ratio (ρ c/ρ b), measured along the two crystallographic axes of single films gives ρ c/ρ b of ≈20 near the transition, with T cs near 90 K. In such films the grain boundary effects can be decoupled from the intrinsic anisotropic properties of YBCO. From oxygen annealing studies it was estimated that the CuO chains supply about 60% of the carriers. From J c measurements it is determined that the orientation of magnetic field with respect to the crystallographic film axes is the primary factor governing the J c values. The angular dependence of J c on the applied magnetic field is compared against various theoretical models showing the best agreement with the modified Ginzburg-Landau's anisotropic mass model (at T ≈ T c) and Tinkham's thin film model (at T < T c). By utilizing the Co-dopant, the coupling between CuO2 planes and the resulting enhancement of the intrinsic anisotropy of YBCO can be studied. Deposition and cooling conditions are shown to be the primary factor that influence the quality of dopant incorporation and the resulting oxygen ordering within the YBCO lattice. Various complex structures and devices utilizing in-plane aligned, a-axis films are presented. Other materials exhibiting in-plane alignment and a-axis growth are described. Optional substrates for achieving such films are also discussed.

Generating mixed morphology BaZrO3 artificial pinning centers for strong and isotropic pinning in BaZrO3-Y2O3 double-doped YBCO thin films

NASA Astrophysics Data System (ADS)

Chen, Shihong; Sebastian, Mary Ann; Gautam, Bibek; Wilt, Jamie; Chen, Yanbin; Sun, Lei; Xing, Zhongwen; Haugan, Timothy; Wu, Judy

2017-12-01

High concentration artificial pinning centers (APCs), such as BaZrO3 nanorods (BZO 1D APCs) aligned along the c-axis of the high temperature superconductor YBa2Cu3O7 (YBCO) can provide strong pinning of magnetic vortices and are desirable for applications in high magnetic fields. Unfortunately, in YBCO films with single-doping (SD) of BZO 1D APCs, a monotonic decreasing superconducting T c and critical current density J c(H) with BZO doping has been observed due to strain field overlap at high-concentration perfectly c-axis aligned BZO 1D APCs. In order to resolve this issue, double-doping (DD) of 2-6 vol% BZO 1D APCs and 3.0 vol% Y2O3 nanoparticles (Y2O3-NPs) in YBCO films has been explored to promote BZO-NR orientation misalignment from the c-axis. Remarkably, a monotonic increasing J c(H) with BZO 1D APCs concentration has been obtained in the BZO DD samples. Such a microstructure change is evidenced in the much smaller c-lattice parameter expansion of 0.103% in the DD samples as opposed to 0.511% in the SD counterparts and reduced c-axis alignment of the BZO 1D APCs as revealed in TEM. This yields a mixed 1D + 2D + 3D APC morphology and enhanced isotropic pinning with respect to the orientation of the H-field in the BZO DD samples.

YBCO High-Temperature Superconducting Filters on M-Plane Sapphire Substrates

NASA Technical Reports Server (NTRS)

Sabataitis, J. C.; Mueller, C. H.; Miranda, F. A.; Warner, J.; Bhasin, K. B.

1996-01-01

Since the discovery of High Temperature Superconductors (HTS) in 1986, microwave circuits have been demonstrated using HTS films on various substrates. These HTS-based circuits have proven to operate with less power loss than their metallic film counterparts at 77 K. This translates into smaller and lighter microwave circuits for space communication systems such as multiplexer filter banks. High quality HTS films have conventionally been deposited on lanthanum aluminate (LaAlO3) substrates. However, LaAlO3 has a relative dielectric constant (epsilon(sub r)) of 24. With a epsilon(sub r) approx. 9.4-11.6, sapphire (Al2O3) would be a preferable substrate for the fabrication of HTS-based components since the lower dielectric constant would permit wider microstrip lines to be used in filter design, since the lower dielectric constant would permit wider microstrip lines to be used for a given characteristic impedance (Z(sub 0)), thus lowering the insertion losses and increasing the power handling capabilities of the devices. We report on the fabrication and characterization of YBa2Cu3O(7-delta) (YBCO) on M-plane sapphire bandpass filters at 4.0 GHz. For a YBCO 'hairpin' filter, a minimum insertion loss of 0.5 dB was measured at 77 K as compared with 1.4 dB for its gold counterpart. In an 'edge-coupled' configuration, the insertion loss went down from 0.9 dB for the gold film to 0.8 dB for the YBCO film at the same temperature.

LANDSAT-D data format control book. Volume 6, appendix A: Partially processed thematic mapper High Density Tape (HDT-AT)

NASA Technical Reports Server (NTRS)

Jai, A.

1982-01-01

One of the outputs of the data management system being developed to provide a variety of standard image products from the thematic mapper and the multispectral band scanners on LANDSAT 4, is the partially processed TM data (radiometric corrections applied and geometric correction matrices for two projections appended) which is recorded on a 28-track high density tape. Specifications are presented for the format of the recorded data as well as for the time code and the major and minor frames of the tape. Major frame types, formats, and field definitions are included.

Processing of SCRIBE data

NASA Astrophysics Data System (ADS)

Sakai, H.

1985-09-01

The SCRIBE experiments were conducted for the purpose of observing the atmospheric infrared emission by using a cryogenic interferometer spectrometer mounted on a balloon-borne platform. The data collected during the flight by the spectrometer were transmitted through the radio telemetry link and were received at the ground station of Holloman AFB where these flights were monitored. They were recorded on analog 1/2 in magnetic tapes running at 60 ips. By playing back these tapes, the telemetry signal transmitted from the balloon-borne package was reporduced at our site for processing efforts to retrieve the interferogram data out of the played-back telemetry signal, and to recover the spectral data corresponding to radiation emitted by the atmosphere were the main objective of this work. In addition to the Holloman tapes, a mobile telemetry signal-receiving unit of AFGL was used to record the flight data on similar analog tapes for the Jul-05-1984 flight launched from Roswell, New Mexico.

Vacuum-free laminated top electrode with conductive tapes for scalable manufacturing of efficient perovskite solar cells

DOE PAGES

Shao, Yuchuan; Wang, Qi; Dong, Qingfeng; ...

2015-06-25

The efficiency of organometal trihalide perovskites (OTP) solar cells have reached that parity of single crystal silicon, and its nature abundant raw material and solution-process capability promise a bright future for commercialization. However, the vacuum based techniques for metal electrode deposition and additional encapsulation layer increase the cost of the perovskite solar cells dramatically and impede their commercialization process. Here, we report a vacuum-free low temperature lamination technique to fabricate the top electrode by commercial conductive tapes (C-tape). The simple fabrication method yields good quality contact and high efficiency device of 12.7%. The C-tapes also encapsulated the devices effectively, resultingmore » in greatly improved device stability. As a result, the combination of lamination of electrodes and encapsulation layers into a single step significantly reduce the cost of device fabrication.« less

Investigation of correlation classification techniques

NASA Technical Reports Server (NTRS)

Haskell, R. E.

1975-01-01

A two-step classification algorithm for processing multispectral scanner data was developed and tested. The first step is a single pass clustering algorithm that assigns each pixel, based on its spectral signature, to a particular cluster. The output of that step is a cluster tape in which a single integer is associated with each pixel. The cluster tape is used as the input to the second step, where ground truth information is used to classify each cluster using an iterative method of potentials. Once the clusters have been assigned to classes the cluster tape is read pixel-by-pixel and an output tape is produced in which each pixel is assigned to its proper class. In addition to the digital classification programs, a method of using correlation clustering to process multispectral scanner data in real time by means of an interactive color video display is also described.

Multilayer ceramic oxide solid electrolyte for fuel cells and electrolysis cells and method for fabrication thereof

NASA Technical Reports Server (NTRS)

Schroeder, James E. (Inventor); Anderson, Harlan U. (Inventor)

1990-01-01

An unitary layered ceramic structure is disclosed which comprises co-sintered layers. The co-sintered structure comprises a sintered central layer of yttria stabilized zirconia (YSZ) which is about 8 mole percent yttria and having a density of at least about 95% of theoretical, and sintered outer layers of strontium lanthanum manganite (LSM) having the approximate molecular composition La.sub.0.8 Sr.sub.0.2 MnO.sub.3, having a density from about 50 to about 60% of theoretical, and having interconnected porosity from about 40 to 50% with an interconnected pore diameter from about one micron to about five microns. The sintered central layer is sandwiched by and bonded and sintered to the outer layers and is essentially free of significant amounts of manganese. A process for making the unitary composition-of-matter is also disclosed which involves tape casting a LSM tape and then on top thereof casting a YSZ tape. The process comprises presintering LSM powder at 1250.degree. F., crushing the presintered commercially available LSM powder, forming a slurry with the crushed LSM, a binder and solvent, tape casting the slurry and allowing the slurry to air dry. A mixture of commercially available submicron size particle YSZ powder is milled with a dispersant and solvent to disperse the YSZ particles thereby forming a dispersed YSZ slurry. The YSZ slurry is then tape cast on the dried LSM tape. If desired, a third layer of LSM can be cast on top of the dried YSZ layer. After drying the composite LSM/YSZ and LSM/YSZ/LSM tapes are fired at 1300.degree. C. No migration of manganese into the YSZ layer was observed with scanning electron microscope/edax in the sintered multilayer tape.

Multilayer ceramic oxide solid electrolyte for fuel cells and electrolysis cells

NASA Technical Reports Server (NTRS)

Schroeder, James E. (Inventor); Anderson, Harlan U. (Inventor)

1991-01-01

A unitary layered ceramic structure is disclosed which comprises co-sintered layers. The co-sintered structure comprises a sintered central layer of yttria stabilized zirconia (YSZ) which is about 8 mole percent yttria and having a density of at least about 95% of theoretical, and sintered outer layers of strontium lanthanum manganite (LSM) having the approximate molecular composition La.sub.0.8 Sr.sub.0.2 MnO.sub.3, having a density from about 50 to about 60% of theoretical, and having interconnected porosity from about 40 to 50% with an interconnected pore diameter from about one micron to about five microns. The sintered central layer is sandwiched by and bonded and sintered to the outer layers and is essentially free of significant amounts of manganese. A process for making the unitary composition-of-matter is also disclosed which involves tape casting a LSM tape and then on top thereof casting a YSZ tape. The process comprises presintering LSM powder at 1250.degree. F., crushing the presintered commercially available LSM powder, forming a slurry with the crushed LSM, a binder and solvent, tape casting the slurry and allowing the slurry to air dry. A mixture of commercially available submicron size particle YSZ powder is milled with a dispersant and solvent to disperse the YSZ particles thereby forming a dispersed YSZ slurry. The YSZ slurry is then tape cast on the dried LSM tape. If desired, a third layer of LSM can be cast on top of the dried YSZ layer. After drying the composite LSM/YSZ and LSM/YSZ/LSM tapes are fired at 1300.degree. C. No migration of manganese into the YSZ layer was observed with scanning electron microscope/edax in the sintered multilayer tape.

Processing Satellite Images on Tertiary Storage: A Study of the Impact of Tile Size on Performance

NASA Technical Reports Server (NTRS)

Yu, JieBing; DeWitt, David J.

1996-01-01

Before raw data from a satellite can be used by an Earth scientist, it must first undergo a number of processing steps including basic processing, cleansing, and geo-registration. Processing actually expands the volume of data collected by a factor of 2 or 3 and the original data is never deleted. Thus processing and storage requirements can exceed 2 terrabytes/day. Once processed data is ready for analysis, a series of algorithms (typically developed by the Earth scientists) is applied to a large number of images in a data set. The focus of this paper is how best to handle such images stored on tape using the following assumptions: (1) all images of interest to a scientist are stored on a single tape, (2) images are accessed and processed in the order that they are stored on tape, and (3) the analysis requires access to only a portion of each image and not the entire image.

Final Report: MATERIALS, STRANDS, AND CABLES FOR SUPERCONDUCTING ACCELERATOR MAGNETS [Grant Number DE-SC0010312

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sumption, Mike D.; Collings, Edward W.

2014-10-29

Our program consisted of the two components: Strand Research and Cable Research, with a focus on Nb3Sn, Bi2212, and YBCO for accelerator magnet applications. We demonstrated a method to refine the grains in Nb3Sn by a factor of two, reaching 45 nm grain sizes, and layer Jcs of 6 kA/mm2 at 12 T. W also measured conductor magnetization for field quality. This has been done both with Nb3Sn conductor, as well as Bi:2212 strand. Work in support of quench studies of YBCO coils was also performed. Cable loss studies in Nb3Sn focused on connecting and comparing persistent magnetization and couplingmore » magnetization for considering their relative impact on HEP machines. In the area of HTS cables, we have investigated both the quench in multistrand YBCO CORC cables, as well as the magnetization of these cables for use in high field magnets. In addition, we examined the magnetic and thermal properties of large (50 T) solenoids.« less

Improved interface growth and enhanced flux pinning in YBCO films deposited on an advanced IBAD-MgO based template

NASA Astrophysics Data System (ADS)

Khan, M. Z.; Zhao, Y.; Wu, X.; Malmivirta, M.; Huhtinen, H.; Paturi, P.

2018-02-01

The growth mechanism is studied from the flux pinning point of view in small-scale YBa2Cu3O6+x (YBCO) thin films deposited on a polycrystalline hastelloy with advanced IBAD-MgO based buffer layer architecture. When compared the situation with YBCO films grown on single crystal substrates, the most critical issues that affect the suitable defect formation and thus the optimal vortex pinning landscape, have been studied as a function of the growth temperature and the film thickness evolution. We can conclude that the best critical current property in a wide applied magnetic field range is observed in films grown at relatively low temperature and having intermediate thickness. These phenomena are linked to the combination of the improved interface growth, to the film thickness related crystalline relaxation and to the formation of linear array of edge dislocations that forms the low-angle grain boundaries through the entire film thickness and thus improve the vortex pinning properties. Hence, the optimized buffer layer structure proved to be particularly suitable for new coated conductor solutions.

Ytterbium coating of spherical Ni(OH) 2 cathode materials for Ni-MH batteries at elevated temperature

NASA Astrophysics Data System (ADS)

He, Xiangming; Wang, Li; Li, Wen; Jiang, Changyin; Wan, Chunrong

The Yb/Co coated nickel hydroxides were prepared by precipitation of Yb(OH) 3 on the surface of spherical nickel hydroxide, followed by precipitation of Co(OH) 2 on its surface. The optimum coating content of ytterbium was around 2% (atomic concentration) to obtain high discharge capacity at 60 °C. It was shown that the discharge capacity of nickel hydroxide at high temperatures was improved by coating of ytterbium and cobalt hydroxide. The high temperature performances of the sealed AAA-sized Ni-MH batteries using Yb/Co coated nickel hydroxide as positive electrodes were carried out, showing much better than those using the un-coated and only Co(OH) 2 coated nickel hydroxide electrodes. The charge acceptance of the battery using 2% Yb and 2% Co coated nickel hydroxide reached 92% at 60 °C, where the charge acceptances for the un-coated and only cobalt coated ones were only 42 and 46%, respectively. It has shown that the Yb/Co coating is an effective way to improve the high temperature performance of nickel hydroxide for nickel-metal hydride batteries.

Preparation and Physical Properties of Segmented Thermoelectric YBa2Cu3O7-x -Ca3Co4O9 Ceramics

NASA Astrophysics Data System (ADS)

Wannasut, P.; Keawprak, N.; Jaiban, P.; Watcharapasorn, A.

2018-01-01

Segmented thermoelectric ceramics are now well known for their high conversion efficiency and are currently being investigated in both basic and applied energy researches. In this work, the successful preparation of the segmented thermoelectric YBa2Cu3O7-x -Ca3Co4O9 (YBCO-CCO) ceramic by hot pressing method and the study on its physical properties were presented. Under the optimum hot pressing condition of 800 °C temperature, 1-hour holding time and 1-ton weight, the segmented YBCO-CCO sample showed two strongly connected layers with the relative density of about 96%. The X-ray diffraction (XRD) patterns indicated that each segment showed pure phase corresponding to each respective composition. Scanning electron microscopy (SEM) results confirmed the sharp interface and good adhesion between YBCO and CCO layers. Although the chemical analysis indicated the limited inter-layer diffusion near the interface, some elemental diffusion at the boundary was expected to be the source of this strong bonding.

Fabrication of YBa2Cu3O7 twin-boundary-junction dc SQUID by using a focused-ion-beam pattern technique

NASA Astrophysics Data System (ADS)

Lee, Sung Hoon; Lee, Soon-Gul

2017-09-01

We have fabricated YBa2Cu3O7 (YBCO) dc SQUIDs containing nanobridges across twin boundaries of LaAlO3 (LAO) substrates as Josephson elements by using a focused ion beam (FIB) etching method and measured their transport properties. The beam energy was 30 keV and the current was 1.5 pA for the nanobridge pattern. Each bridge with a nominal width of 200 nm crossed a twin boundary in the (100) direction. The SQUID loop had a 10 μm × 10 μm hole with a 5.7 μm average linewidth. The SQUID voltage showed modulations in response to the external flux with a maximum modulation depth of 350 μV at 77.0 K. HR-XRD spectra showed that the epitaxially grown YBCO film was twinned in commensurate with the twinning of the LAO substrate. Tilting of the c-axis of YBCO across the twin boundary is believed to play a role as a tunnel barrier.

The early growth and interface of YBa 2Cu 3O y thin films deposited on YSZ substrates

NASA Astrophysics Data System (ADS)

Gao, J.; Tang, W. H.; Yau, C. Y.

2001-11-01

Epitaxial thin films of YBa 2Cu 3O y (YBCO) have been prepared on yttrium-stabilized zirconia substrates with and without a buffer layer. The early growth, crystallinity and surface morphology of these thin films have been characterized by X-ray diffraction, rocking curves, scanning electron microscope, in situ conductance measurements, and surface step profiler. The full width at half maximum of the ( 0 0 5 ) peak of rocking curve was found to be less than 0.1°. Over a wide scanning range of 2000 μm the average surface roughness is just 5 nm, indicating very smooth films. Grazing incident X-ray reflection and positron annihilation spectroscopy shows well-defined interfaces between layers and substrate. By applying a new Eu 2CuO 4 (ECO) buffer layer the initial formation of YBCO appears to grow layer-by-layer rather than the typical island growth mode. The obtained results reveal significant improvements at the early formation and crystallinity of YBCO by using the 214-T ‧ ECO as a buffer layer.

Magnetic Field Satellite (Magsat) data processing system specifications

NASA Technical Reports Server (NTRS)

Berman, D.; Gomez, R.; Miller, A.

1980-01-01

The software specifications for the MAGSAT data processing system (MDPS) are presented. The MDPS is divided functionally into preprocessing of primary input data, data management, chronicle processing, and postprocessing. Data organization and validity, and checks of spacecraft and instrumentation are dicussed. Output products of the MDPS, including various plots and data tapes, are described. Formats for important tapes are presented. Dicussions and mathematical formulations for coordinate transformations and field model coefficients are included.

Experiments and FE modeling of stress-strain state in ReBCO tape under tensile, torsional and transverse load

NASA Astrophysics Data System (ADS)

Ilin, K.; Yagotintsev, K. A.; Zhou, C.; Gao, P.; Kosse, J.; Otten, S. J.; Wessel, W. A. J.; Haugan, T. J.; van der Laan, D. C.; Nijhuis, A.

2015-05-01

For high current superconductors in high magnet fields with currents in the order of 50 kA, single ReBCO coated conductors must be assembled in a cable. The geometry of such a cable is mostly such that combined torsion, axial and transverse loading states are anticipated in the tapes and tape joints. The resulting strain distribution, caused by different thermal contraction and electromagnetic forces, will affect the critical current of the tapes. Tape performance when subjected to torsion, tensile and transverse loading is the key to understanding limitations for the composite cable performance. The individual tape material components can be deformed, not only elastically but also plastically under these loads. A set of experimental setups, as well as a convenient and accurate method of stress-strain state modeling based on the finite element method have been developed. Systematic measurements on single ReBCO tapes are carried out combining axial tension and torsion as well as transverse loading. Then the behavior of a single tape subjected to the various applied loads is simulated in the model. This paper presents the results of experimental tests and detailed FE modeling of the 3D stress-strain state in a single ReBCO tape under different loads, taking into account the temperature dependence and the elastic-plastic properties of the tape materials, starting from the initial tape processing conditions during its manufacture up to magnet operating conditions. Furthermore a comparison of the simulations with experiments is presented with special attention for the critical force, the threshold where the tape performance becomes irreversibly degraded. We verified the influence of tape surface profile non-uniformity and copper stabilizer thickness on the critical force. The FE models appear to describe the tape experiments adequately and can thus be used as a solid basis for optimization of various cabling concepts.

Bit error rate performance of Image Processing Facility high density tape recorders

NASA Technical Reports Server (NTRS)

Heffner, P.

1981-01-01

The Image Processing Facility at the NASA/Goddard Space Flight Center uses High Density Tape Recorders (HDTR's) to transfer high volume image data and ancillary information from one system to another. For ancillary information, it is required that very low bit error rates (BER's) accompany the transfers. The facility processes about 10 to the 11th bits of image data per day from many sensors, involving 15 independent processing systems requiring the use of HDTR's. When acquired, the 16 HDTR's offered state-of-the-art performance of 1 x 10 to the -6th BER as specified. The BER requirement was later upgraded in two steps: (1) incorporating data randomizing circuitry to yield a BER of 2 x 10 to the -7th and (2) further modifying to include a bit error correction capability to attain a BER of 2 x 10 to the -9th. The total improvement factor was 500 to 1. Attention is given here to the background, technical approach, and final results of these modifications. Also discussed are the format of the data recorded by the HDTR, the magnetic tape format, the magnetic tape dropout characteristics as experienced in the Image Processing Facility, the head life history, and the reliability of the HDTR's.

Freeze Tape Casting of Functionally Graded Porous Ceramics

NASA Technical Reports Server (NTRS)

Sofie, Stephen W.

2007-01-01

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.

Comparison of the Microstructure and Flux Pinning Properties of Polycrystalline YBa2Cu3O7-d Containing Zn0.95Mn0.05O or Al2O3 Nanoparticles

NASA Astrophysics Data System (ADS)

Al-Mohsin, R. A.; Al-Otaibi, A. L.; Almessiere, M. A.; Al-badairy, H.; Slimani, Y.; Ben Azzouz, F.

2018-07-01

Here we compare the microstructure and flux pinning properties of polycrystalline YBa2Cu3O7-d (Y-123 or YBCO) containing either Al2O3 or Zn0.95Mn0.05O nanoparticles. Samples were prepared using a standard solid-state reaction process, and nanoparticles were added up to a concentration of 0.1 wt%. The crystal structure, microstructure, electrical and magnetic properties were analyzed using X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM), and electrical resistivity and DC magnetization measurements, respectively. TEM observations showed that the addition of Zn0.95Mn0.05O resulted in a high density of fine twins and a variety of interacting microstructures, while Al2O3 addition resulted in a high density of Al-rich nanoscale inhomogeneities embedded in the Y-123 matrix. Flux pinning forces were determined, and predominant pinning mechanisms in the prepared samples were proposed. We evaluated the superconducting properties of YBCO considering the effects of adding insulating or magnetic nanoparticles.

The homogeneity of levitation force in single domain YBCO bulk

NASA Astrophysics Data System (ADS)

Zhou, Keran; Xu, Ke-Xi; Wu, Xing-da; Pan, Peng-jun

2007-11-01

The pellet homogeneity of levitation force versus the position in comparison to the seed or to the top surface has been studied in the entire volume of a single domain YBa 2Cu 3O 7-δ bulk sample processed by the top-seeded melt texturing growth (TSMTG). It is found that the levitation forces increase and peak at a depth of 3 mm from the top of the sample at liquid nitrogen temperature. In other words, the second disk has the largest levitation force density. The phenomenon can be interpreted by the interaction between the microcracks or pores produced by crystal growth and the oxygenation. We propose a model in which Y211 particles distribution leading to microcracks and pores reduces the effective induced shielding current loops (ISCL) and increases the perimeters of ISCL. This corresponds to a decrease in the grain size and results in greatly reduced levitation forces of the bottom of the bulk. From the research, we know that the density of the YBCO bulk is also an important parameter for the levitation properties. The result is very attractive and useful for the fundamental studies and fabrication of TSMTG YBa 2Cu 3O 7-δ bulk.

Comparison of the Microstructure and Flux Pinning Properties of Polycrystalline YBa2Cu3O7-d Containing Zn0.95Mn0.05O or Al2O3 Nanoparticles

NASA Astrophysics Data System (ADS)

Al-Mohsin, R. A.; Al-Otaibi, A. L.; Almessiere, M. A.; Al-badairy, H.; Slimani, Y.; Ben Azzouz, F.

2018-03-01

Here we compare the microstructure and flux pinning properties of polycrystalline YBa2Cu3O7-d (Y-123 or YBCO) containing either Al2O3 or Zn0.95Mn0.05O nanoparticles. Samples were prepared using a standard solid-state reaction process, and nanoparticles were added up to a concentration of 0.1 wt%. The crystal structure, microstructure, electrical and magnetic properties were analyzed using X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM), and electrical resistivity and DC magnetization measurements, respectively. TEM observations showed that the addition of Zn0.95Mn0.05O resulted in a high density of fine twins and a variety of interacting microstructures, while Al2O3 addition resulted in a high density of Al-rich nanoscale inhomogeneities embedded in the Y-123 matrix. Flux pinning forces were determined, and predominant pinning mechanisms in the prepared samples were proposed. We evaluated the superconducting properties of YBCO considering the effects of adding insulating or magnetic nanoparticles.

Electron-positron momentum distribution measurements of high-T(sub c) superconductors and related systems

NASA Astrophysics Data System (ADS)

Wachs, A. L.; Turchi, P. E. A.; Howell, R. H.; Jean, Y. C.; Fluss, M. J.; West, R. N.; Kaiser, J. H.; Rayner, S.; Hahgighi, H.; Merkle, K. L.

1989-06-01

We discuss our measurements of the 2D-angular correlation of positron annihilation radiation (ACAR) in La(sub 2)CuO(sub 4), YBa(sub 2)Cu(sub 3)O(sub 7) (YBCO), and NiO. The measurements for NiO are the first such 2D-ACAR measurements; the YBCO results are of a higher statistical quality than previously reported in the literature. The data are compared with complementary theoretical calculations and with each other. We discuss the implication of our analysis for ACAR studies of similar and related systems.

High-Tc superconductor coplanar waveguide filter

NASA Technical Reports Server (NTRS)

Chew, Wilbert; Bajuk, Louis J.; Cooley, Thomas W.; Foote, Marc C.; Hunt, Brian D.; Rascoe, Daniel L.; Riley, A. L.

1991-01-01

Coplanar waveguide (CPW) low-pass filters made of YBa2Cu3O(7-delta) (YBCO) on LaAlO3 substrates, with dimensions suited for integrated circuits, were fabricated and packaged. A complete filter gives a true idea of the advantages and difficulties in replacing thin-film metal with a high-temperature superconductor in a practical circuit. Measured insertion losses in liquid nitrogen were superior to the loss of a similar thin-film copper filter throughout the 0- to 9.5-GHz passband. These results demonstrate the performance of fully patterned YBCO in a practical CPW structure after sealing in a hermetic package.

Fatigue and retention in ferroelectric Y-Ba-Cu-O/Pb-Zr-Ti-O/Y-Ba-Cu-O heterostructures

NASA Astrophysics Data System (ADS)

Ramesh, R.; Chan, W. K.; Wilkens, B.; Gilchrist, H.; Sands, T.; Tarascon, J. M.; Keramidas, V. G.; Fork, D. K.; Lee, J.; Safari, A.

1992-09-01

Fatigue and retention characteristics of ferroelectric lead zirconate titanate thin films grown with Y-Ba-Cu-O(YBCO) thin-film top and bottom electrodes are found to be far superior to those obtained with conventional Pt top electrodes. The heterostructures reported here have been grown in situ by pulsed laser deposition on yttria-stabilized ZrO2 buffer [100] Si and on [001] LaAlO3. Both the a- and c-axis orientations of the YBCO lattice have been used as electrodes. They were prepared using suitable changes in growth conditions.

Present status and future prospect of coated conductor development and its application in Japan

NASA Astrophysics Data System (ADS)

Shiohara, Y.; Yoshizumi, M.; Izumi, T.; Yamada, Y.

2008-03-01

The current national project on coated conductors using Y-system superconductors has been carried out over the project period (FY2003-FY2007). In this paper, the current status and the future prospect of this project are reviewed. The high performance tape development group, consisting of Fujikura and SRL-NCCC, has worked on the tape by PLD-REBCO superconducting layers on PLD-CeO2/IBAD-GZO buffered substrates. A high product of Ic and L, higher than 112 166 A m, was achieved in a 368 m-304.8 A GdBCO tape whose Ic value is mostly above 350 A/cm in width. The performance under magnetic field was also improved up to 42 A at 3 T in a GdBCO short film with doping of ZrO2. 61 m long GdBCO tape with ZrO2 doping showed a high Ic value of 220 A at self field and 30 A at 3 T. On the other hand, another group focusing on low production cost has worked on TFA-MOD and MOCVD processes. The extremely high Ic value of 735 A/cm-w was obtained in TFA-MOD films on PLD-CeO2/IBAD-GZO/Hastelloy substrate due to the effect of Ba-poor nominal composition. In efforts towards long tape production by the SWCC group, a 200 m long tape with a high Ic value of 200 A/cm-w was obtained using a batch-type furnace. The Ic × L value of this tape was 40 000 A m, which is the highest value in the world obtained by the TFA-MOD process. Based on the above achievements in coated conductor process development, two new additional goals were set in the project. One is the development of extremely low cost tape and the other is the development of the basic technologies for making electric power devices of cables, transformers, motors, current-limiters and cryocoolers. Some of the new investigations have already revealed marvellous results, such as a 15 kW motor, low AC loss coils, low AC loss cables, etc.

DOE Office of Scientific and Technical Information (OSTI.GOV)

RHODES, WILLIAM

As part of the HEU Blend Down project, aluminum tape is required to seal aluminum tubes that will hold contaminated Mark 22 fuel tubes for dissolution. From a large field of candidate tapes, Avery Dennison's Fasson 0802 tape (synthetic rubber adhesive system) was found to be acceptable for this application. This tape will disentangle in the normal H-Canyon dissolver solution and have no detrimental effect on the H-Canyon process. Upon placement of Fasson 0802 tape into the dissolver solution, nitric acid will attack and disentangle the block copolymer network and destroy the adhesive nature of the material, resulting in insolublemore » particles that can be removed via centrifuge operations (cake weight increase of no more than 1 percent). The addition of the tape will not generate off-gas products and the resultant solution characteristics (surface tension, viscosity, density, and disengagement time) will be unaffected. Further, the potential effect on the down-stream evaporation system is negligible. Since the tape will not be placed in a high radiation environment, radiation stability is not an issue. Through detailed discussions with Avery Dennison chemists and based on analytical tests, a fairly detailed understanding of the constituents comprising the proprietary adhesive system has been assembled. Most importantly, chlorine was not detected in the aluminum tape (neutron activation analysis detection limit is 16 ppm). Finally, application of this tape will not impact LEU specifications.« less

Advanced Airframe Structural Materials: A Primer and Cost Estimating Methodology

DTIC Science & Technology

1991-01-01

laying machines for larger, mildly con- toured parts such as wing and stabilizer skins. For such parts, automated tape laying machines can operate many...heat guns (90-130°F). However, thermoplastics require as much as 650°F for forming. Automated tape laying machines for these materials use warm...cycles to properly seat the plies onto the tool. This time-consuming process can sometimes be eliminated or reduced by the use of automated tape laying procedures

Radar image processing module development program, phase 3

NASA Technical Reports Server (NTRS)

1977-01-01

The feasibility of using charge coupled devices in an IPM for processing synthetic aperture radar signals onboard the NASA Convair 990 (CV990) aircraft was demonstrated. Radar data onboard the aircraft was recorded and processed using a CCD sampler and digital tape recorder. A description of equipment and testing was provided. The derivation of the digital presum filter was documented. Photographs of the sampler/tape recorder, real time display and circuit boards in the IPM were also included.

Control of Y-211 content in bulk YBCO superconductors fabricated by a buffer-aided, top seeded infiltration and growth melt process

NASA Astrophysics Data System (ADS)

Namburi, Devendra K.; Shi, Yunhua; Palmer, Kysen G.; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

2016-03-01

Bulk (RE)-Ba-Cu-O ((RE)BCO, where RE stands for rare-earth), single grain superconductors can trap magnetic fields of several tesla at low temperatures and therefore can function potentially as high field magnets. Although top seeded melt growth (TSMG) is an established process for fabricating relatively high quality single grains of (RE)BCO for high field applications, this technique suffers from inherent problems such as sample shrinkage, a large intrinsic porosity and the presence of (RE)2BaCuO5 (RE-211)-free regions in the single grain microstructure. Seeded infiltration and growth (SIG), therefore, has emerged as a practical alternative to TSMG that overcomes many of these problems. Until now, however, the superconducting properties of bulk materials processed by SIG have been inferior to those fabricated using the TSMG technique. In this study, we identify that the inferior properties of SIG processed bulk superconductors are related to the presence of a relatively large Y-211 content (˜41.8%) in the single grain microstructure. Controlling the RE-211 content in SIG bulk samples is particularly challenging because it is difficult to regulate the entry of the liquid phase into the solid RE-211 preform during the infiltration process. In an attempt to solve this issue, we have investigated the effect of careful control of both the infiltration temperature and the quantity of liquid phase powder present in the sample preforms prior to processing. We conclude that careful control of the infiltration temperature is the most promising of these two process variables. Using this knowledge, we have fabricated successfully a YBCO bulk single grain using the SIG process of diameter 25 mm that exhibits a trapped field of 0.69 T at 77 K, which is the largest value reported to date for a sample fabricated by the SIG technique.

Procedural Due Process in Indian Education. Scripts for a Two-Part Filmstrip/Audio Tape Program. Curriculum Bulletin 18.03.

ERIC Educational Resources Information Center

Streiff, Paul R.

In 1974 new sections added to the Code of Federal Regulations and the Indian Affairs Field Manual required the establishment of programs of student rights and responsibilities and due process procedures in schools operated or funded by the Bureau of Indian Affairs. This two-part filmstrip and audio tape program is designed to assist educators and…

Low Loss Substrates for Microwave Applications and Sol-Gel Processing of Superconductors

DTIC Science & Technology

1994-03-31

crystallographic axis normal to solid state technology, in the growth of ferrimagnetic garnets the substrate plane) or. better, in "epitaxial" films (i.e...hay- by liquid phase epitaxy ( LPE ). is from a melt using a para- ing their three crystallographic axes related to those of a magnetic garnet structure...yttrium barium cuprate (YBCO) films and their microwave applications have been carried out. Several promising new hosts such as Sr(All/2Tal/2)03, Sr(Al1

Method for preparation of textured YBa.sub.2 Cu.sub.3 O.sub.x superconductor

DOEpatents

Selvamanickam, Venkat; Goyal, Amit; Kroeger, Donald M.

1998-01-01

The present invention relate to textured YBa.sub.2 Cu.sub.3 O.sub.x (Y-123) superconductors and a process of preparing them by directional recrystallization of compacts fabricated from quenched YBCO powders at temperatures about 100.degree. C. below the peritectic temperature to provide a superconductor where more than 75% of the YBa.sub.2 Cu.sub.3 O.sub.x phase is obtained without any Y.sub.2 BaCuO.sub.5 .

Enhanced quench propagation in 2G-HTS coils co-wound with stainless steel or anodised aluminium tapes

NASA Astrophysics Data System (ADS)

Núñez-Chico, A. B.; Martínez, E.; Angurel, L. A.; Navarro, R.

2016-08-01

Early quench detection and thermal stability of superconducting coils are of great relevance for practical applications. Magnets made with second generation high temperature superconducting (2G-HTS) tapes present low quench propagation velocities and therefore slow voltage development and high local temperature rises, which may cause irreversible damage. Since quench propagation depends on the anisotropy of the thermal conductivity, this may be used to achieve an improvement of the thermal stability and robustness of 2G-HTS coils. On pancake type coils, the thermal conductivity along the tapes (coil’s azimuthal direction) is mostly fixed by the 2G-HTS tape characteristics, so that the reduction of anisotropy relies on the improvement of the radial thermal conductivity, which depends on the used materials between superconducting tapes, as well as on the winding and impregnation processes. In this contribution, we have explored two possibilities for such anisotropy reduction: by using anodised aluminium or stainless steel tapes co-wound with the 2G-HTS tapes. For all the analysed coils, critical current distribution, minimum quench energy values and both tangential and radial quench propagation velocities at different temperatures and currents are reported and compared with the results of similar coils co-wound with polyimide (Kapton®) tapes.

Effect of Tape Burnishing and Drive Use on Head Wear in Rotary Tape Drives

NASA Astrophysics Data System (ADS)

Bhushan, Bharat; Anderson, Reid M.; Koinkar, Vilas N.

Three types of 12.7-mm wide metal particle tapes were studied. One of the tapes was calendered, whereas the other two tapes were additionally burnished one or two times using a proprietary process. Each type of tape was studied after 100 passes in the BetaCam SP drive and also in the virgin (0 pass) state. It was reported that in the case of the unburnished tape, head wear was high in the first pass and decreased during use. However, head wear for the double burnished tape was low for the first pass and increased during use. Whereas in the single burnished tape, head wear was low in the first pass and remained low. The objective of this study is to understand the mechanisms for loss and growth of head wear by correlating the surface characteristics of the tapes to head wear rate and to determine the changes in the surface characteristics occurring from 0 to 100 passes in the drive. It was found that summit density, mean and rms summit height, and mean and rms summit curvature correlate well to the head wear data. During manufacture and use in the drive, as the summit density, mean and rms summit height, and mean and rms summit curvature decrease, the head wear rate decreases. The mechanism for head wear is the initial ploughing of dense, sharp and high tape asperities into the surface of the head material resulting in a high head wear rate and a high coefficient of friction. Double burnishing during manufacturing removes high asperities, thus making the tape very smooth and possibly results in high adhesion and head wear growth with use. Chemical changes of the tape surface during double burnishing (not part of this study) also may be responsible for head wear growth during use.

The Repack Challenge

NASA Astrophysics Data System (ADS)

Kruse, Daniele Francesco

2014-06-01

Physics data stored in CERN tapes is quickly reaching the 100 PB milestone. Tape is an ever-changing technology that is still following Moore's law in terms of capacity. This means we can store every year more and more data in the same amount of tapes. However this doesn't come for free: the first obvious cost is the new higher capacity media. The second less known cost is related to moving the data from the old tapes to the new ones. This activity is what we call repack. Repack is vital for any large tape user: without it, one would have to buy more tape libraries and more floor space and, eventually, data on old non supported tapes would become unreadable and be lost forever. In this paper we describe the challenge of repacking 115 PB before LHC data taking starts in the beginning of 2015. This process will have to run concurrently with the existing experiment tape activities, and therefore needs to be as transparent as possible for users. Making sure that this works out seamlessly implies careful planning of the resources and the various policies for sharing them fairly and conveniently. To tackle this problem we need to fully exploit the speed and throughput of our modern tape drives. This involves proper dimensioning and configuration of the disk arrays and all the links between them and the tape servers, i.e the machines responsible for managing the tape drives. It is also equally important to provide tools to improve the efficiency with which we use our tape libraries. The new repack setup we deployed has on average increased tape drive throughput by 80%, allowing them to perform closer to their design specifications. This improvement in turn means a 48% decrease in the number of drives needed to achieve the required throughput to complete the full repack on time.

Uncovering a new quasi-2D CuO2 plane between the YBa2Cu3O7 and CeO2 buffer layer of coated conductors

NASA Astrophysics Data System (ADS)

Li, Zhi-Xin; Cao, Jin-Jin; Gou, Xiao-Fan; Wang, Tian-Ge; Xue, Feng

2018-01-01

We report a discovery of the quasi-two-dimensional (quasi-2D) CuO2 plane between the superconductor YBa2Cu3O7 (YBCO) and CeO2 buffer layer (mostly used in the fabrication) of coated conductors through the atomistic computer simulations with the molecular dynamics (MD) and first-principle calculations. For an YBCO coated conductor with multilayer structures, the buffer layers deposited onto a substrate are mainly considered to transfer a strong biaxial texture from the substrate to the YBCO layer. To deeply understand the tuning mechanism of the texture transfer, exploring the complete atomic-level picture of the structure between the YBa2Cu3O7/CeO2 interfaces is firstly required. However, the related observation data have not been available due to some big challenges of experimental techniques. With the MD simulations, having tested the accuracy of the potential functions for the YBa2Cu3O7/CeO2 interface, we constructed a total of 54 possible atom stacking models of the interface and identified its most appropriate and stable structure according to the criterion of the interface adhesion energy and the coherent characterization. To further verify the stability of the identified structure, we performed the first-principle calculations to obtain the adhesion energy and developed the general knowledge of the interface structure. Finally, a coherent interface formed with a new built quasi-2D CuO2 plane that is structurally similar to the CuO2 plane inside bulk YBCO was determined.

Positron Annihilation Measurements of High Temperature Superconductors

NASA Astrophysics Data System (ADS)

Jung, Kang

1995-01-01

The temperature dependence of positron annihilation parameters has been measured for basic YBCO, Dy-doped, and Pr-doped superconducting compounds. The physical properties, such as crystal structure, electrical resistance, and critical temperature, have been studied for all samples. In the basic YBCO and Dy-doped samples, the defect -related lifetime component tau_{2 } was approximately constant from room temperature to above the critical temperature and then showed a step -like decrease in the temperature range 90K { ~} 40K. No significant temperature dependence was found in the short- and long-lifetime components, tau_{1} and tau_{3}. The x-ray diffraction data showed that the crystal structure of these two samples was almost the same. These results indicated that the electronic structure changed below the critical temperature. No transition was observed in the Pr-doped YBCO sample. The advanced computer program "PFPOSFIT" for positron lifetime analysis was modified to run on the UNIX system of the University of Utah. The destruction of superconductivity with Pr doping may be due to mechanisms such as hole filling or hole localization of the charge carriers and may be related to the valence state of the Pr ion. One-parameter analyses like the positron mean lifetime parameter and the Doppler line shape parameter S also have been studied. It was found that a transition in Doppler line shape parameter S was associated with the superconducting transition temperature in basic YBCO, Dy -doped, and 0.5 Pr-doped samples, whereas no transition was observed in the nonsuperconducting Pr-doped sample. The Doppler results indicate that the average electron momentum at the annihilation sites increases as temperature is lowered across the superconducting transition range and that electronic structure change plays an important role in high temperature superconductivity.

LANDSAT-D data format control book. Volume 6, appendix K: Unprocessed multispectral scanner high density tape (HDT-RM/HDT-GM)

NASA Technical Reports Server (NTRS)

Andersen, K. E.

1981-01-01

Unprocessed MSS data which is recorded on HDT-RM (a 28 track, high density tape) and on HDT-GM (a 14 track, nonbias recorded, high density tape) are inputs for the LANDSAT 4 data management system. All MSS data initially recorded on HDT-GM are copied to HDT-RM prior to processing. This specification establishes the requirements for the format of the LANDSAT D HDT-RM/HDT-GM.

Multifunctional Composites with Applications to Energy Performance and Efficiency

DTIC Science & Technology

2011-08-01

surface for comparing the effects of processing. Parylene/ Teflon AF adhesion was measured using a modified tape test. Samples were razor cut (3-6...lines, 2 mm spacing ) at 0 and 90 degrees to the tape -pull direction. SEMicro CHT tape (synthetic rubber adhesive, 12 to 25 mm wide x 75 mm long) was...surface, a thin layer of Teflon AF (~200 nm) is spin- coated for hydrophobicity. Small drops of ionic liquids in contact with a conductive probe are

First 65nm tape-out using inverse lithography technology (ILT)

NASA Astrophysics Data System (ADS)

Hung, Chi-Yuan; Zhang, Bin; Tang, Deming; Guo, Eric; Pang, Linyong; Liu, Yong; Moore, Andrew; Wang, Kechang

2005-11-01

This paper presents SMIC's first 65nm tape out results, in particularly, using ILT. ILT mathematically determines the mask features that produce the desired on-wafer results with best wafer pattern fidelity, largest process window or both. SMIC applied it to its first 65nm tape-out to study ILT performance and benefits for deep sub-wavelength lithography. SMIC selected 3 SRAM designs as the first test case, because SRAM bit-cells contain features which are challenging lithographically. Mask patterns generated from both conventional OPC and ILT were placed on the mask side-by-side. Mask manufacturability (including fracturing, writing time, inspection, and metrology) and wafer print performance of ILT were studied. The results demonstrated that ILT achieved better CD accuracy, produced substantially larger process window than conventional OPC, and met SMIC's 65nm process window requirements.

Natural Resource Information System. Volume 2: System operating procedures and instructions

NASA Technical Reports Server (NTRS)

1972-01-01

A total computer software system description is provided for the prototype Natural Resource Information System designed to store, process, and display data of maximum usefulness to land management decision making. Program modules are described, as are the computer file design, file updating methods, digitizing process, and paper tape conversion to magnetic tape. Operating instructions for the system, data output, printed output, and graphic output are also discussed.

The standards process: Technical committee X3B5 digital magnetic tape

NASA Technical Reports Server (NTRS)

Cheatham, Sam

1993-01-01

The definition of X3B5, where it fits in the national and international standards development process, and how it interfaces and influences the world community of standards developers are provided. Details concerning the focus of the committee, how it operates, and what the group sees as the future trends in the area of interchange standards utilizing the multifaceted, ubiquitous magnetic tape are presented.

Evaluation of non-specular reflecting silvered Teflon and filled adhesives

NASA Technical Reports Server (NTRS)

Bourland, G.; Cox, R. L.

1981-01-01

A non-specular silver-Teflon tape thermal control coating was tested to provide the data necessary to qualify it for use on the Space Shuttle Orbiter radiators. Effects of cure cycle temperature and pressure on optical and mechanical properties on the silver-Teflon tape were evaluated. The baseline Permacel P-223 adhesive, used with the specular silver-Teflon tape initially qualified for the Orbiter radiators, and four alternate metal-filled and unfilled adhesives were evaluated. Tests showed the cure process has no effect on the silver-Teflon optical properties, and that the baseline adhesive cure cycle gives best results. In addition the P-223 adhesive bond is more reproducible than the alternates, and the non-specular tape meets both the mechanical and the optical requirements of the Orbiter radiator coating specification. Existing Orbiter coating techniques were demonstrated to be effective in aplying the non-specular tape to a curved panel simulating the radiators. Author

NASA Astrophysics Data System (ADS)

Good, J.; Bracanovic, D.

The development of High Temperature Superconductors (HTS) conductors makes it possible to build very high field superconducting magnets up to at least 25 T. Previously, the only way to obtain a steady field of 25 T for research would be to use water cooled copper solenoids. To achieve 25 T in a 50 mm working space would require about 10 MW of power with a large water cooling plant to carry away the heat. With such high powers involved it is difficult to have a stable and quiet magnetic field environment in which to make sensitive measurements such as NMR. Both capital and operating costs are high so few such facilities exist worldwide. This makes a superconducting magnet of 25 T a very attractive proposition. Figure 1 shows that the critical current of HTS as compared to NbTi and NbSn. The latter can be used up to a limit of about 20 T at 4.2 K. The HTS on the other hand shows the potential of much higher fields. The two main issues in magnet design are the maximum critical current and the maximum stress that a conductor or coil structure can support. For the inner sections of the coil the forces are modest but as the diameter increases towards the outside of the coil hoop stress becomes the dominant issue. Cryogenic has built a magnet system with first generation BSCCO conductor. It is designed to run at 4.2 K. It has a three section design, two of conventional superconductor and one of HTS. • The outer winding is made from NbTi giving a field of 9 T, in a bore of 225 mm. The coil is made from 21 km of NbTi wire graded from 1 to 0.6 mm diameter. • A middle coil of NbSn bronze route conductor providing a field of 14 T in 140 mm diameter. • An inner set of HTS coils. These are in the form of 3 coaxial windings made from silver matrix BSCCO conductor supplied by American Superconductor. This conductor has a critical current of 100 A at 77 K in zero field. At 4 K in low field the current is very much higher. The set of three BSCCO windings has a gauss per amp of 157 and when run on its own at a current of 300 A provides a field of 4.7 T, although currents above 275 A begin to show significant resistive losses in the conductor. The inner BSCCO coils are separately powered from the outer magnet. In a test of the full magnet system the BSCCO coil is ramped up at various background fields up to 13 T. The resulting voltage loss across the BSCCO is shown in Fig. 2. This test shows that the BSCCO conductor can operate up to 275 A quite successfully independent of the background field with just a slight increase in resistive losses presumably from the joints between conductor being magneto-resistive or due to flux flow in the conductor. Since the BSCCO coils were made new 2nd generation conductors have become available made from thin films of YBCO on a stainless steel backing. These have a much higher effective current density. A 4 mm wide tape of BSCCO is 0.4 mm thick but carries a similar current to an YBCO tape of 0.01 mm or even 0.05 mm thickness. Table 1 shows the properties of different conductors compared. Interestingly the conductors are not just higher current density but also more flexible and stronger in tension. A new coil has now been produced from 0.1 mm Super Power material of a size that can fit inside the existing winding so that the combination can produce above 6 T providing a total field of 20 T at 4.2 K in a working bore of 38 mm. Now that the new 2nd generation YBCO based conductors have become available it is intended to exchange the BSCCO coils for YBCO windings which will allow this magnet to operate at much higher fields of up to 25 T. At this field it will be the highest field superconducting magnet worldwide. The magnet is housed in a liquid helium cryostat. To reduce helium consumption a powerful 2nd stage cryocooler is fitted to the cryostat. The first stage cools a shield around the liquid helium to 45 K. The second stage has a cooling power of 1.5 W at 4.2 K and is used to recondense helium gas evolved from the magnet. In operation, with no current in the leads to the cryocooler it is able to condense more gas than that evolved from the cryostat so the liquid helium level will increase with time. Except at the highest currents the cryostat is a zero loss magnet system. A cross section of cryostat and magnet is show in Fig 3. The power required for the cryocooler is 6.5 kW while that for the magnet power supplies and ancillary electronics is 2 kW giving a combined power requirement of 8.5 kW. This compares very favourably with the typical value of 10 MW required by a water cooled copper solenoid to achieve the same field. Note from Publisher: This article contains the abstract only.

Critical current densities in superconducting Y-Ba-Cu-O prepared by chelating method

NASA Astrophysics Data System (ADS)

Fujisawa, Tadashi; Okuyama, Katsuro; Ohshima, Shigetoshi; Takagi, Akira

1990-10-01

The IDA, NTA, HEDTA, EDTA, TTHA, and DTPA chelating agents have been used to prepare the Y-Ba-Cu-O compounds whose critical current is presently investigated. It is noted that the precursor YBCO prepared from large stability-constant metal complexes (HEDTA, EDTA, DTPA, and TTHA) exhibited very fine and homogeneous particles. The critical current density of a 1 x 4 x 15 mm block of YBCO sintered at 880-910 C for 24 h and subsequently annealed at 500 C in an O2 flow was approximately 500 A/sq cm at 77 K, in zero magnetic field.

Coaxial line configuration for microwave power transmission study of YBa2Cu3O(7-delta) thin films

NASA Technical Reports Server (NTRS)

Chorey, C. M.; Miranda, F. A.; Bhasin, K. B.

1991-01-01

Microwave transmission measurements through YBa2Cu3O(7-delta) (YBCO) high-transition-temperature superconducting thin films on lanthanum aluminate (LaAlO3) have been performed in a coaxial line at 10 GHz. LaAlO3 substrates were ultrasonically machined into washer-shaped discs, polished, and coated with laser-ablated YBCO. These samples were mounted in a 50-ohm coaxial air line to form a short circuit. The power transmitted through the films as a function of temperature was used to calculate the normal state conductivity and the magnetic penetration depth for the films.

Dual nature of 3 d electrons in YbT 2 Zn 20 (T = Co; Fe) evidenced by electron spin resonance

DOE PAGES

Ivanshin, V. A.; Litvinova, T. O.; Gimranova, K.; ...

2015-03-18

The electron spin resonance experiments were carried out in the single crystals YbFe 2Zn 20. The observed spin dynamics is compared with that in YbCo 2Zn 20 and Yb 2Co 12P 7 as well as with the data of inelastic neutron scattering and electronic band structure calculations. Our results provide direct evidence that 3d electrons are itinerant in YbFe 2Zn 20 and localized in YbCo 2Zn 20. Possible connection between spin paramagnetism of dense heavy fermion systems, quantum criticality effects, and ESR spectra is discussed.

Static and dynamic stability of the guidance force in a side-suspended HTS maglev system

NASA Astrophysics Data System (ADS)

Zhou, Dajin; Cui, Chenyu; Zhao, Lifeng; Zhang, Yong; Wang, Xiqing; Zhao, Yong

2017-02-01

The static and dynamic stability of the guidance force in a side-suspended HTS-PMG (permanent magnetic guideway) system were studied theoretically and experimentally. It is found that there are two types of guidance force that exist in the HTS-PMG system, which are sensitive to the levitation gap and the arrangement of YBCO bulks around the central axis of the PMG. An optimized YBCO array was used to stabilize the system, which enabled a side-suspended HTS-PMG maglev vehicle to run stably at 102 km h-1 on a circular test track with 6.5 m in diameter.

Electronic structure in high temperature superconducting oxides

NASA Astrophysics Data System (ADS)

Howell, R. H.; Sterne, P.; Solal, F.; Fluss, M. J.; Tobin, J.; Obrien, J.; Radousky, H. B.; Haghighi, H.; Kaiser, J. H.; Rayner, S. L.

1991-08-01

We have performed measurements on entwined single crystals of YBCO using both photoemission and positron angular correlation of annihilation radiation and on single crystals of LSCO using only angular correlation. Fermi surface features in good agreement with band theory were found and identified in all of the measurements. In photoemission, the Fermi momentum was fixed for several points and the band dispersion below the Fermi energy was mapped. In positron angular correlation measurements, the shape of the Fermi surface was mapped for the CuO chains (YBCO) and the CuO planes (LSCO). Demonstration of the existence of Fermi surfaces in the HTSC materials points a direction for future theoretical considerations.

Effect of the Cu/Ba ratio for the YBCO deposition onto IBAD template by the MOCVD method

NASA Astrophysics Data System (ADS)

Choi, J. K.; Kim, H. J.; Jun, B. H.; Kim, C. J.

2005-10-01

YBa2Cu3O7-x (YBCO) thin films were fabricated by the metal organic chemical vapor deposition (MOCVD) using a single liquid source. The copper/barium (Cu/Ba) ratio was varied from 1.26 to 1.38 to optimize the deposition condition. The IBAD template (CeO2/YSZ/stainless steel) was used as a substrate. The growth features of the YBCO films were not significantly influenced by the Cu/Ba ratio, while the superconducting transition temperature (Tc) and critical current (Ic) depended on the Cu/Ba ratio. When Cu/Ba ratio was between 1.26 and 1.29, Tc was as low as 80 K, while as Cu/Ba ratio increased to 1.38, it increased to above 85 K. The highest Tc (89.0 K) and Ic (46.3 A/cm-width) were achieved at the Cu/Ba ratio of 1.38 (Y:Ba:Cu = 1:2.1:2.9). It indicates that the optimum Cu/Ba ratio which differs from stoichiometric balance exists for the formation of the superconducting phase with a high Tc and Ic in MOCVD method.

Grain growth simulation of [001] textured YBCO films grown on (001) substrates with large lattice misfit: Prediction of misorientations of the remaining boundaries

NASA Astrophysics Data System (ADS)

Tsai, Jack W. H.; Ling, Shiun; Rodriguez, Julio C.; Mustapha, Zarina; Chan, Siu-Wai

2001-04-01

We study the effects of (1) the variation of grain boundary energy with misorientation and (2) the large lattice misfit (>3%) between the films and substrates on grain growth in films by method of Monte Carlo simulations. The results from the grain growth simulation in YBa2Cu3O7-x (YBCO) films was found to concur with previous experimental observation of preferred grain orientations for YBCO films deposited on various substrates such as (001) magnesium oxide (MgO) and (001) yttria stabilized zirconia (YSZ). The simulation has helped us to identify three factors influencing the competition of these [001] tilt boundaries. They are: (1) the relative depths of local minima in the boundary energy vs. misorientation curve, (2) the number of combinations of coincidence epitaxy (CE) orientations contributing to the exact misorientation for each of the high-angle-but-low-energy (HABLE) boundaries, and (3) the number of combinations of CE orientations within the angular ranges bracketing each of the exact HABLE boundaries. Hence, these factors can be applied to clarify the origin of special misorientations observed experimentally.

Program documentation for the space environment test division post-test data reduction program (GNFLEX)

NASA Technical Reports Server (NTRS)

Jones, L. D.

1979-01-01

The Space Environment Test Division Post-Test Data Reduction Program processes data from test history tapes generated on the Flexible Data System in the Space Environment Simulation Laboratory at the National Aeronautics and Space Administration/Lyndon B. Johnson Space Center. The program reads the tape's data base records to retrieve the item directory conversion file, the item capture file and the process link file to determine the active parameters. The desired parameter names are read in by lead cards after which the periodic data records are read to determine parameter data level changes. The data is considered to be compressed rather than full sample rate. Tabulations and/or a tape for generating plots may be output.

Magnetic tape

NASA Technical Reports Server (NTRS)

Robinson, Harriss

1992-01-01

The move to visualization and image processing in data systems is increasing the demand for larger and faster mass storage systems. The technology of choice is magnetic tape. This paper briefly reviews the technology past, present, and projected. A case is made for standards and the value of the standards to users.

Fabrication Of Carbon-Boron Reinforced Dry Polymer Matrix Composite Tape

NASA Technical Reports Server (NTRS)

Belvin, Harry L.; Cano, Roberto J.; Treasure, Monte; Shahood, Thomas W.

1999-01-01

Future generation aerospace vehicles will require specialized hybrid material forms for component structure fabrication. For this reason, high temperature composite prepregs in both dry and wet forms are being developed at NASA Langley Research Center (LaRC). In an attempt to improve compressive properties of carbon fiber reinforced composites, a hybrid carbon-boron tape was developed and used to fabricate composite laminates which were subsequently cut into flexural and compression specimens and tested. The hybrid material, given the designation HYCARB, was fabricated by modifying a previously developed process for the manufacture of dry polymer matrix composite (PMC) tape at LaRC. In this work, boron fibers were processed with IM7/LaRC(TradeMark)IAX poly(amide acid) solution-coated prepreg to form a dry hybrid tape for Automated Tow Placement (ATP). Boron fibers were encapsulated between two (2) layers of reduced volatile, low fiber areal weight poly(amide acid) solution-coated prepreg. The hybrid prepreg was then fully imidized and consolidated into a dry tape suitable for ATP. The fabrication of a hybrid boron material form for tow placement aids in the reduction of the overall manufacturing cost of boron reinforced composites, while realizing the improved compression strengths. Composite specimens were press-molded from the hybrid material and exhibited excellent mechanical properties.

A new tape product for optical data storage

NASA Technical Reports Server (NTRS)

Larsen, T. L.; Woodard, F. E.; Pace, S. J.

1993-01-01

A new tape product has been developed for optical data storage. Laser data recording is based on hole or pit formation in a low melting metallic alloy system. The media structure, sputter deposition process, and media characteristics, including write sensitivity, error rates, wear resistance, and archival storage are discussed.

75 FR 32231 - Small Business Size Standards: Waiver of the Nonmanufacturer Rule

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-07

... for configured tape library storage equipment. SUMMARY: The U.S. Small Business Administration (SBA... Storage Equipment. SBA is initiating a request that an class waiver be granted for Configured Tape Library Storage Equipment, Product Service Code (PSC) 7025 Automated Data Processing (ADP) Input/ Output and...

Superconducting flat tape cable magnet

DOEpatents

Takayasu, Makoto

2015-08-11

A method for winding a coil magnet with the stacked tape cables, and a coil so wound. The winding process is controlled and various shape coils can be wound by twisting about the longitudinal axis of the cable and bending following the easy bend direction during winding, so that sharp local bending can be obtained by adjusting the twist pitch. Stack-tape cable is twisted while being wound, instead of being twisted in a straight configuration and then wound. In certain embodiments, the straight length should be half of the cable twist-pitch or a multiple of it.

Effects of Kinesio taping and exercise on forward head posture.

PubMed

Shih, Hsu-Sheng; Chen, Shu-Shi; Cheng, Su-Chun; Chang, Hsun-Wen; Wu, Pei-Rong; Yang, Jin-Shiou; Lee, Yi-Shuang; Tsou, Jui-Yi

2017-01-01

Little is known about the effects of Kinesio taping and therapeutic exercise on correcting forward head posture. To compare Kinesio taping versus therapeutic exercise for forward head posture on static posture, dynamic mobility and functional outcomes. Sixty subjects (31 women, 29 men) with forward head postures participated in this study. They were randomly assigned to either one of the three groups: (1) exercise group (n = 20), (2) taping group (n = 20), and (3) control groups (n = 20). The horizontal forward displacement (HFD) between ear lobe and acromion process, upper cervical and lower cervical angle (UCA, LCA), active range of motion (AROM) of cervical spine, and neck disability index (NDI) were measured before and after a 5-week intervention, and a 2-week follow-up. Data were analyzed by means of a mixed design repeated-measures ANOVA. Both taping and exercise groups showed significant improvements in HFD compared with the control group at post-treatment and follow-up. Compared with the control group, the exercise group exhibited significant improvements in the LCA and the side bending AROM at post-treatment. Both Kinesio taping and therapeutic exercise improve forward head posture after intervention and a 2-week follow-up. The effectiveness of therapeutic exercise is better than taping.

Bread: CDC 7600 program that processes Spent Fuel Test Climax data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hage, G.L.

BREAD will process a family of files copied from a data tape made by Hewlett-Packard equipment employed for data acquisition on the Spent Fuel Test-Climax at NTS. Tapes are delivered to Livermore approximately monthly. The process at this stage consists of four steps: read the binary files and convert from H-P 16-bit words to CDC 7600 60-bit words; check identification and data ranges; write the data in 6-bit ASCII (BCD) format, one data point per line; then sort the file by identifier and time.

Superconducting-electromagnetic hybrid bearing using YBCO bulk blocks for passive axial levitation

NASA Astrophysics Data System (ADS)

Nicolsky, R.; de Andrade, R., Jr.; Ripper, A.; David, D. F. B.; Santisteban, J. A.; Stephan, R. M.; Gawalek, W.; Habisreuther, T.; Strasser, T.

2000-06-01

A superconducting/electromagnetic hybrid bearing has been designed using active radial electromagnetic positioning and a superconducting passive axial levitator. This bearing has been tested for an induction machine with a vertical shaft. The prototype was conceived as a four-pole, two-phase induction machine using specially designed stator windings for delivering torque and radial positioning simultaneously. The radial bearing uses four eddy-current sensors, displaced 90° from each other, for measuring the shaft position and a PID control system for feeding back the currents. The stator windings have been adapted from the ones of a standard induction motor. The superconducting axial bearing has been assembled with commercial NdFeB permanent magnets and a set of seven top-seeded-melt-textured YBCO large-grain cylindrical blocks. The bearing set-up was previously simulated by a finite element method for different permanent magnet-superconductor block configurations. The stiffness of the superconducting axial bearing has been investigated by measuring by a dynamic method the vertical and transversal elastic constants for different field cooling processes. The resulting elastic constants show a linear dependence on the air gap, i.e. the clearance between the permanent magnet assembly and the set of superconducting large-grain blocks, which is dependent on cooling distance.

Design, processing and testing of LSI arrays: Hybrid microelectronics task

NASA Technical Reports Server (NTRS)

Himmel, R. P.; Stuhlbarg, S. M.; Ravetti, R. G.; Zulueta, P. J.

1979-01-01

Mathematical cost factors were generated for both hybrid microcircuit and printed wiring board packaging methods. A mathematical cost model was created for analysis of microcircuit fabrication costs. The costing factors were refined and reduced to formulae for computerization. Efficient methods were investigated for low cost packaging of LSI devices as a function of density and reliability. Technical problem areas such as wafer bumping, inner/outer leading bonding, testing on tape, and tape processing, were investigated.

Rotational molding of pultruded profiles reinforced polyethylene

NASA Astrophysics Data System (ADS)

Greco, Antonio; Maffezzoli, Alfonso; Romano, Giorgio

2014-05-01

The aim of this paper is the production of fiber reinforced LLDPE components by rotational molding. To this purpose, a process upgrade was developed, for the incorporation of pultruded tapes in the rotational molding cycle. Pultruded tapes, made of 50% by weight of glass fibers dispersed in a high density polyethylene(HDPE) matrix, were glued on the internal surface of a cubic mold, and rotational molding process was run using the same processing conditions used for conventional LLDPE processing. During processing, melting of LLDPE powders and of HDPE allowed to incorporate the tapes inside rotational molded LLDPE. The glass fiber reinforced prototypes were characterized in terms of mechanical properties. Plate bending tests were performed on the square faces extracted from the rotational molded product. The rotational molding products were also subjected to internal hydrostatic pressure tests up to 10 bar. In any case, no failure of the cubic samples was observed. In both cases, it was found that addition of a single pultruded strips, which corresponds to addition of about 0.6% by weight of glass fibers, involved an increase of the stiffness of the faces by about 25%.

Ultra low noise YBa{sub 2}Cu{sub 3}O{sub 7−δ} nano superconducting quantum interference devices implementing nanowires

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arpaia, R.; CNR-SPIN, Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II,” I-80125 Napoli; Arzeo, M.

2014-02-17

We present results on ultra low noise YBa{sub 2}Cu{sub 3}O{sub 7–δ} (YBCO) nano Superconducting QUantum Interference Devices (nanoSQUIDs). To realize such devices, we implemented high quality YBCO nanowires, working as weak links between two electrodes. We observe critical current modulation as a function of an externally applied magnetic field in the full temperature range below the transition temperature T{sub C}. The white flux noise below 1μΦ{sub 0}/√(Hz) at T=8 K makes our nanoSQUIDs very attractive for the detection of small spin systems.

Microwave surface resistance of MgB2

NASA Astrophysics Data System (ADS)

Zhukov, A. A.; Purnell, A.; Miyoshi, Y.; Bugoslavsky, Y.; Lockman, Z.; Berenov, A.; Zhai, H. Y.; Christen, H. M.; Paranthaman, M. P.; Lowndes, D. H.; Jo, M. H.; Blamire, M. G.; Hao, Ling; Gallop, J.; MacManus-Driscoll, J. L.; Cohen, L. F.

2002-04-01

The microwave power and frequency dependence of the surface resistance of MgB2 films and powder samples were studied. Sample quality is relatively easy to identify by the breakdown in the ω2 law for poor-quality samples at all temperatures. The performance of MgB2 at 10 GHz and 21 K was compared directly with that of high-quality YBCO films. The surface resistance of MgB2 was found to be approximately three times higher at low microwave power and showed an onset of nonlinearity at microwave surface fields ten times lower than the YBCO film. It is clear that MgB2 films are not yet optimized for microwave applications.

Application of ceramic superconductors in high speed turbines

NASA Technical Reports Server (NTRS)

Mcmichael, C. K.; Lamb, M. A.; Lin, M. W.; Ma, K. B.; Chu, W. K.

1992-01-01

A turbine system was modified to adapt melt textured YBa2Cu3O(7-delta) (YBCO) with high energy permanent magnets to form a hybrid superconducting magnetic bearing (HSMB). The HSMB/turbine prototype has achieved a static axial thrust capacity exceeding 41 N/sq cm (60 psi) and a radial magnetic stiffness of 7 N/mm in a field cooled state at 77 K. A comparison was made between different configurations of magnets and superconductor for radial stability, axial instability, and force hystereses. This systematic study lead to a greater understanding of the interactions between YBCO and high energy permanent magnets to define design parameters for high rotational devices using the HSMB design.

YBCO microbolometer operating below Tc - A modelization based on critical current-temperature dependence

NASA Astrophysics Data System (ADS)

Robbes, D.; Langlois, P.; Dolabdjian, C.; Bloyet, D.; Hamet, J. F.; Murray, H.

1993-03-01

Using careful measurements of the I-V curve of a YBCO thin-film microbridge under light irradiation at 780 nm and temperature close to 77 K, it is shown that the critical current versus temperature dependence is a good thermometer for estimating bolometric effects in the film. A novel dynamic voltage bias is introduced which directly gives the device current responsitivity and greatly reduces risks of thermal runaway. Detectivity is very low but it is predicted that a noise equivalent temperature of less than 10 exp -7 K/sq rt Hz would be achievable in a wide temperature range (10-80 K), which is an improvement over thermometry at the resistive transition.

Engaging David in the Reading Process.

ERIC Educational Resources Information Center

Nierstheimer, Susan L.

2002-01-01

Describes the experiences of an undergraduate student in a reading methods course during her practicum of tutoring a young child with reading difficulties. Discusses how she finally found a motivational tool that repeatedly engaged the child--tape recording the child as he read a predictable book and playing the tape back for the child to listen…

Effect of phase assemblage of precursor on the fabrication process and properties of Bi2223 tape sheathed with Ag-alloy

NASA Astrophysics Data System (ADS)

Nakamura, Y.; Shioiri, T.; Kurihara, C.; Machida, T.; Inada, R.; Oota, A.

2008-09-01

The use of alloy sheath is effective to increase the strength of Ag-sheathed Bi2223 tapes. However, the Jc value of alloy sheathed tapes was not high enough since the undesired reaction to form impurity phases and the change in formation rate of Bi2223 were disturbed by the microstructure of the filaments . In this study, the effect of 2223 contents in precursor on the formation and property of Bi2223 tapes sheathed with Ag-Mg alloy was investigated. The conversion rate of Bi2223 from Bi2212 was increased by the addition of Bi2223 phase in precursor but the conversion rate in Ag-Mg alloy sheathed tapes was slower than that in the Ag-Cu alloy sheathed tapes. This reduction of conversion speed of Bi2223 may be attributed to the decrease in the growth rate of Bi2223 crystals in Ag-Mg alloy sheath. Since the tapes with small Bi2223 crystals after first sintering showed many outgrowths after final sintering, the formation of outgrowth would be caused in the case of small crystal size. The Jc value of 2.2 × 10 4 A/cm 2 was achieved in the samples using the precursor with 10 wt.% 2223. The high Jc value can be achieved by the proper control of precursor condition including the contents of Bi2223 and corresponding heat treatment pattern in Ag-Mg alloy sheathed tapes.

Directly connecting the Very Long Baseline Array

NASA Astrophysics Data System (ADS)

Hunt, Gareth; Romney, Jonathan D.; Walker, R. Craig

2002-11-01

At present, the signals received by the 10 antennas of the Very Long Baseline Array (VLBA) are recorded on instrumentation tapes. These tapes are then shipped from the antenna locations - distributed across the mainland USA, the US Virgin Islands, and Hawaii - to the processing center in Socorro, New Mexico. The Array operates today at a mean sustained data rate of 128 Mbps per antenna, but peak rates of 256 Mbps and 512 Mbps are also used. Transported tapes provide the cheapest method of attaining these bit rates. The present tape system derives from wideband recording techniques dating back to the late 1960s, and has been in use since the commissioning of the VLBA in 1993. It is in need of replacement on a time scale of a few years. Further, plans are being developed which would increase the required data rates to 1 Gbps in 5 years and 100 Gbps in 10 years. With the advent of higher performance networks, it should be possible to transmit the data directly to the processing center. However, achieving this connectivity is complicated by the remoteness of the antennas -

Effects of wear on structure-sensitive magnetic properties of ceramic ferrite in contact with magnetic tape

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Buckley, D. H.; Tanaka, K.

1985-01-01

Wear experiments and electron microscopy and diffraction studies were conducted to examine the wear and deformed layers in single-crystal Mn-Zn (ceramic) ferrite magnetic head material in contact with magnetic tape and the effects of that contact on magnetic properties. The crystalline state of the single-crystal magnetic head was changed drastically during the sliding process. A nearly amorphous structure was produced on its wear surface. Deformation in the surficial layer of the magnetic head was a critical factor in readback signal loss above 2.5 dB. The signal output level was reduced as applied normal load was increased. Considerable plastic flow occurred on the magnetic tape surface with sliding, and the signal loss due to the tape wear was approximately 1 dB.

NASA Global Atmospheric Sampling Program (GASP) data report for tape VL0005

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Humenik, F. M.

1977-01-01

Atmospheric ozone, water vapor, and related flight and meteorological data were obtained during 214 flights of a United Airlines B-747 and two Pan American World Airways B-747's from March through June 1976. In addition, trichlorofluoromethane data obtained from laboratory analysis of two whole air samples collected in flight are reported. These data are available on GASP tape VL0005 from the National Climatic Center, Asheville, North Carolina. In addition to the GASP data, tropopause pressure fields obtained from NMC archives for the dates of the GASP flights are included on the data tape. Flight routes and dates, instrumentation, data processing procedures, and data tape specifications are described in this report. Selected analyses including ozone and sample bottle data are also presented.

Tape casting and partial melting of Bi-2212 thick films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buhl, D.; Lang, T.; Heeb, B.

1994-12-31

To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density ofmore » 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).« less

Tape casting and partial melting of Bi-2212 thick films

NASA Technical Reports Server (NTRS)

Buhl, D.; Lang, TH.; Heeb, B.; Gauckler, L. J.

1995-01-01

To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 microns. The orientation of the (a,b)-plane of the grains was parallel to the substrate with a misalignment of less than 6 deg. At 77 K/0T a critical current density of 15, 000 A/sq cm was reached in films of the dimension 1 cm x 2 cm x 20 microns (1 micron V/cm criterion, resistively measured). At 4 K/0T the highest value was 350,000 A/sq cm (1 nV/cm criterion, magnetically measured).

An analysis of the surface-normal coupling efficiency of a metal grating coupler embedded in a Scotch tape optical waveguide

NASA Astrophysics Data System (ADS)

Barrios, Carlos Angulo; Canalejas-Tejero, Víctor

2017-01-01

The coupling efficiency at normal incidence of recently demonstrated aluminum grating couplers integrated in flexible Scotch tape waveguides has been analyzed theoretically and experimentally. Finite difference time domain (FDTD) and rigorously coupled wave analysis (RCWA) methods have been used to optimize the dimensions (duty cycle and metal thickness) of Scotch tape-embedded 1D Al gratings for maximum coupling at 635 nm wavelength. Good dimension and tape refractive index tolerances are predicted. FDTD simulations reveal the incident beam width and impinging position (alignment) values that avoid rediffraction and thus maximize the coupling efficiency. A 1D Al diffraction grating integrated into a Scotch tape optical waveguide has been fabricated and characterized. The fabrication process, based on pattern transfer, has been optimized to allow complete Al grating transfer onto the Scotch tape waveguide. A maximum coupling efficiency of 20% for TM-polarized normal incidence has been measured, which is in good agreement with the theoretical predictions. The measured coupling efficiency is further increased up to 28% for TM polarization under oblique incidence. Temperature dependence measurements have been also achieved and related to the simulations results and fabrication procedure.

Interplay between current driven ferromagnetism in charge ordered antiferromagnetic Pr0.5Ca0.5MnO3 and superconducting YBa2Cu3O7-δ thin film multilayer

NASA Astrophysics Data System (ADS)

Baisnab, Dipak Kumar; Sardar, Manas; Amaladass, E. P.; Vaidhyanathan, L. S.; Baskaran, R.

2018-07-01

Thin film multilayer heterostructure of alternate YBa2Cu3O7-δ (YBCO) and Pr0.5Ca0.5MnO3 (PCMO) with thickness of each layer ∼60 nm has been deposited on (100) oriented SrTiO3 substrate by Pulsed Laser Deposition technique. A half portion of the base YBCO layer was masked in situ using mechanical shadow mask and in the remaining half portion, five alternate layers of PCMO and YBCO thin films were deposited. Magnetoresistance measurements were carried out under externally applied magnetic field and injection current. A noticeable damped oscillation of the superconducting transition temperature (TC) of this multilayer with respect to magnetic field is seen. Curiously, the field at which the first minimum in TC occurs, decreases as an injection current is driven perpendicular/parallel to the multilayers. Both these phenomena indicate that ferromagnetic correlation can be induced in antiferromagnetic PCMO thin films by (1) external magnetic field, or (2) injection current. While (1) is well researched, our study indicates that ferromagnetism can be induced by small amount of current in PCMO thin films. This unusual behavior points towards the strongly correlated nature of electrons in PCMO.

Isotropic enhancement in the critical current density of YBCO thin films incorporating nanoscale Y2BaCuO5 inclusions

NASA Astrophysics Data System (ADS)

Jha, Alok K.; Matsumoto, Kaname; Horide, Tomoya; Saini, Shrikant; Mele, Paolo; Ichinose, Ataru; Yoshida, Yutaka; Awaji, Satoshi

2017-09-01

The effect of incorporation of nanoscale Y2BaCuO5 (Y211) inclusions on the vortex pinning properties of YBa2Cu3O7-δ (YBCO or Y123) superconducting thin films is investigated in detail on the basis of variation of critical current density (JC) with applied magnetic field and also with the orientation of the applied magnetic field at two different temperatures: 77 K and 65 K. Surface modified target approach is employed to incorporate nanoscale Y211 inclusions into the superconducting YBCO matrix. The efficiency of Y211 nanoinclusions in reducing the angular anisotropy of critical current density is found to be significant. The observed angular dependence of the critical current density is discussed on the basis of mutually occupied volume by a vortex and spherical and/or planar defect. A dip in JC near the ab-plane is also observed which has been analyzed on the basis of variation of pinning potential corresponding to a spherical (3-D) or planar (2-D) pinning center and has been attributed to a reduced interaction volume of the vortices with a pinning center and competing nature of the potentials due to spherical and planar defects.

Third order intermodulation distortion in HTS Josephson Junction downconverter at 12GHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Katsumi; Hayashi, Kunihiko; Fujimoto, Manabu

1994-12-31

Here the authors first report on the microwave characteristics of the third order intermodulation distortion(IMD3) in High-Tc Superconductor (HTS) Josephson Junction (JJ) Downconverter at 12GHz. They have successfully developed high quality nonlinear YBCO microbridge Josephson junctions for such an active MMIC as a mixer with RF, LO, IF and bias filters, which have been fabricated on (100) MgO substrates with 20mm x 20mm x 0.5mm dimensions. The minimum conversion loss of the JJ mixer is 11 dB at very small local microwave input power LO= {minus}20dBm which is two order less than Schottky diode mixer. Consequently, this small optimum LOmore » power gives the small RF input power at which the output IF power of the YBCO mixer saturates. Two-tone third-order intercept point(IP3) performance is a significantly important figure of merit typically used to define linearity of devices and circuits. The RF input power = {minus}15dBm at the IP3 point is obtained for the YBCO mixer at 15K and LO = 10.935GHz with {minus}22dBm. The have successfully measured the dependence of IMD3 on temperature, bias current and LO power.« less

A K-band Frequency Agile Microstrip Bandpass Filter using a Thin Film HTS/Ferroelectric/dielectric Multilayer Configuration

NASA Technical Reports Server (NTRS)

Subramanyam, Guru; VanKeuls, Fred; Miranda, Felix A.

1998-01-01

We report on YBa2Cu3O(7-delta) (YBCO) thin film/SrTiO3 (STO) thin film K-band tunable bandpass filters on LaAlO3 (LAO) dielectric substrates. The 2 pole filter has a center frequency of 19 GHz and a 4% bandwidth. Tunability is achieved through the non-linear dc electric field dependence of the relative dielectric constant of STO(epsilon(sub rSTO). A large tunability ((Delta)f/f(sub 0) = (f(sub Vmax) - f(sub 0)/f(sub 0), where f(sub 0) is the center frequency of the filter at no bias and f(sub Vmax) is the center frequency of the filter at the maximum applied bias) of greater than 10% was obtained in YBCO/STO/LAO microstrip bandpass filters operating below 77 K. A center frequency shift of 2.3 GHz (i.e., a tunability factor of approximately 15%) was obtained at a 400 V bipolar dc bias, and 30 K, with minimal degradation in the insertion loss of the filter. This paper addresses design, fabrication and testing of tunable filters based on STO ferroelectric thin films. The performance of the YBCO/STO/LAO filters is compared to that of gold/STO/LAO counterparts.

Architectural constructs of Ampex DST

NASA Technical Reports Server (NTRS)

Johnson, Clay

1993-01-01

The DST 800 automated library is a high performance, automated tape storage system, developed by AMPEX, providing mass storage to host systems. Physical Volume Manager (PVM) is a volume server which supports either a DST 800, DST 600 stand alone tape drive, or a combination of DST 800 and DST 600 subsystems. The objective of the PVM is to provide the foundation support to allow automated and operator assisted access to the DST cartridges with continuous operation. A second objective is to create a data base about the media, its location, and its usage so that the quality and utilization of the media on which specific data is recorded and the performance of the storage system may be managed. The DST tape drive architecture and media provides several unique functions that enhance the ability to achieve high media space utilization and fast access. Access times are enhanced through the implementation of multiple areas (called system zones) on the media where the media may be unloaded. This reduces positioning time in loading and unloading the cartridge. Access times are also reduced through high speed positioning in excess of 800 megabytes per second. A DST cartridge can be partitioned into fixed size units which can be reclaimed for rewriting without invalidating other recorded data on the tape cartridge. Most tape management systems achieve space reclamation by deleting an entire tape volume, then allowing users to request a 'scratch tape' or 'nonspecific' volume when they wish to record data to tape. Physical cartridge sizes of 25, 75, or 165 gigabytes will make this existing process inefficient or unusable. The DST cartridge partitioning capability provides an efficient mechanism for addressing the tape space utilization problem.

Shared Bibliographic Input Network (SBIN) Conference Proceedings, October 1982

DTIC Science & Technology

1982-10-01

records for their document collections. In the process of development of the CIRCANET requirements, we conceived a flowchart (figure 3) of the ideal system...with beginners ). b. If an error is made when taping, it can be detecteA and corrected on screen before writing onto the tape being used for input. c...It’s an easier and quicker method for beginners to become familiar with all of the fields and their entries. d. If a record is lost during the process

Rotorcraft Use in Disaster Relief and Mass Casualty Incidents - Case Studies

DTIC Science & Technology

1990-06-01

Disaster Relief and Mass 6. Performing Organization Code C asuallty Incidents- C ase Studies 8._P rfo minOr ani ati nR porNo 7. Author (s) 8...disaster planning process; and 3) produce a color video tape promoting the need for and the use of rotorcraft and heliports in disaster relief. 17...disaster prepaLedness ageicies for use in the integration of local helicopter assets into the disaster planning process; and 3) produce a color video tape

Fully synthetic taped insulation cables

DOEpatents

Forsyth, E.B.; Muller, A.C.

1983-07-15

The present invention is a cable which, although constructed from inexpensive polyolefin tapes and using typical impregnating oils, furnishes high voltage capability up to 765 kV, and has such excellent dielectric characteristics and heat transfer properties that it is capable of operation at capacities equal to or higher than presently available cables at a given voltage. This is accomplished by using polyethylene, polybutene or polypropylene insulating tape which has been specially processed to attain properties which are not generally found in these materials, but are required for their use in impregnated electrical cables. Chief among these properties is compatibility with impregnating oil.

What can Andreev bound states tell us about superconductors?

PubMed

Millo, Oded; Koren, Gad

2018-08-06

Zero-energy Andreev bound states, which manifest themselves in the tunnelling spectra as zero-bias conductance peaks (ZBCPs), are abundant at interfaces between superconductors and other materials and on the nodal surface of high-temperature superconductors. In this review, we focus on the information such excitations can provide on the properties of superconductor systems. First, a general introduction to the physics of Andreev bound states in superconductor/normal metal interfaces is given with a particular emphasis on why they appear at zero energy in d -wave superconductors. Then, specific spectroscopic tunnelling studies of thin films, bilayers and junctions are described, focusing on the corresponding ZBCP features. Scanning tunnelling spectroscopy (STS) studies show that the ZBCPs on the c -axis YBa 2 Cu 3 O 7- δ (YBCO) films are correlated with the surface morphology and appear only in proximity to (110) facets. STS on c -axis La 1.88 Sr 0.12 CuO 4 (LSCO) films exhibiting the 1/8 anomaly shows spatially modulated peaks near zero bias associated with the anti-phase ordering of the d -wave order parameter predicted at this doping level. ZBCPs were also found in micrometre-size edge junctions of YBCO/SrRuO 3 /YBCO, where SrRuO 3 is ferromagnetic. Here, the results are consistent with a crossed Andreev reflection effect (CARE) at the narrow domain walls of the SrRuO 3 ZBCPs measured in STS studies of manganite/cuprate bilayers could not be attributed to CARE because the manganite's domain wall is much larger than the coherence length in YBCO, and instead are attributed to proximity-induced triplet-pairing superconductivity with non-conventional symmetry. And finally, ZBCPs found in junctions of non-intentionally doped topological insulator films of Bi 2 Se 3 and the s -wave superconductor NbN are attributed to proximity-induced p x  + ip y triplet order parameter in the topological material.This article is part of the theme issue 'Andreev bound states'. © 2018 The Author(s).

Experimental transport studies of yttrium barium copper oxide and lambda-DNA

NASA Astrophysics Data System (ADS)

Zhang, Yuexing

This dissertation consists of two parts. In Part I, we focus on the quasi-particle transport properties in the high temperature superconductor YBa2Cu3O7-delta (YBCO), probed by the thermal Hall conductivity (kappa xy). The thermal Hall conductivity selectively reflects the transport behaviors of the charge carriers. By measuring kappaxy in the normal state YBCO, we established a new method to determine the Wiedemann-Franz (WF) ratio in cuprates. We determined the Hall-channel WF ratio kappa xy/sigmaxyT in Cu and YBCO. In the latter, we uncovered a T-linear dependence and suppression of the Hallchannel WF ratio. The suppression of the Hall-channel WF ratio in systems with predominant electron-electron scattering will be discussed. Thermal transport behaviors of the quasi-particles in the mixed state were studied by measuring kappaxx and kappa xy in a high-purity YBCO crystal. From the field-dependence of the thermal conductivity kappaxx, we separated the quasi particle contribution (kappae) from the phonon background. In the Hall channel, we observed that the (weak-field) kappa xy increased 103-fold between T c (90 K) and 30 K, implying a 100-fold enhancement of the quasi-particle lifetime. We found that kappaxy exhibited a specific scaling behavior below ˜30 K. The implication of the scaling behavior will be discussed. In Part II, we describe an experiment on determining the electrical conductivity of the bacteriophage lambda-DNA, an issue currently under intense debate. We covalently bonded the DNA to Au electrodes by incorporating thiol modified dTTP into the 'sticky' ends of the lambda-DNA. Two-probe measurements on such molecules provided a lower bound for the resistivity rho > 10 6 mum at bias potentials up to 20 V, in conflict with recent claims of moderate to high conductivity. We stress the importance of eliminating salt residues in these measurements.

Crystallographic orientation mapping with an electron backscattered diffraction technique in (Bi, Pb)2Sr2Ca2Cu3O10 superconductor tapes

NASA Astrophysics Data System (ADS)

Tan, T. T.; Li, S.; Oh, J. T.; Gao, W.; Liu, H. K.; Dou, S. X.

2001-02-01

It is believed that grain boundaries act as weak links in limiting the critical current density (Jc) of bulk high-Tc superconductors. The weak-link problem can be greatly reduced by elimination or minimization of large-angle grain boundaries. It has been reported that the distribution of the Jc in (Bi, Pb)2Sr2Ca2Cu3O10+x (Bi2223) superconductor tapes presents a parabolic relationship in the transverse cross section of the tapes, with the lowest currents occurring at the centre of the tapes. It was proposed that the Jc distribution is strongly dependent on the local crystallographic orientation distribution of the Bi2223 oxides. However, the local three-dimensional crystallographic orientation distribution of Bi2223 crystals in (Bi, Pb)2Sr2Ca2Cu3O10+x superconductor tapes has not yet been experimentally determined. In this work, the electron backscattered diffraction technique was employed to map the crystallographic orientation distribution, determine the misorientation of grain boundaries and also map the misorientation distribution in Bi2223 superconductor tapes. Through crystallographic orientation mapping, the relationship between the crystallographic orientation distribution, the boundary misorientation distribution and the fabrication parameters may be understood. This can be used to optimize the fabrication processes thus increasing the critical current density in Bi2223 superconductor tapes.

The Exploration, Discovery, Recovery, and Preservation of Endangered Electronic Scientific Records, the Lunar Orbiter Image Recovery Project

NASA Astrophysics Data System (ADS)

Wingo, D. R.; Harper, M.

2017-12-01

In 1966 and 1967 NASA sent five photo reconnaissance satellites to the Moon to scout out sites for the first Apollo landings. This was the first mission in human history to extensively map the Moon to one meter resolution. The Lunar Orbiter spacecraft obtained photographs via 70 millimeter film in high resolution (one meter), and medium resolution (7-8) meter. Each mission took approximately 200 medium and high resolution photographs. These were processed in an on board film laboratory and then scanned via a 6.5 micron light beam.. These images were then transmitted to the Earth as analog waveforms double modulated as a vestigial sideband (VSB) and Frequency Modulation With Feedback (FMFB). The spacecraft transmissions were received at NASA's Deep Space Network at Goldstone (DSS-12), Madrid (DSS-61) and Woomera (DSS-41). The signals received were shifted to a 10 MHz intermediate frequency spectrum which was then written to 2"analog instrumentation tape drives (Ampex-FR-900's). In parallel the signals were demodulated and displayed on a kinescope, which then was photographed using a 35mm camera, and the 35mm film was then rephotographed, processed, and printed for initial analysis by the landing site selection team. The magnetic tape based analog sigals preserved the higher dynamic range of the spacecraft 70mm film, and this was then digitized utilizing digitizer and fed to a Univac 1170 computer for analysis of rock height, slope angles, and geologic context. After the Apollo missions these tapes were largely forgotten. In 2007, retired NASA archivist Nancy Evans, who had saved the last surviving Ampex FR-900's donated the drives to the Lunar Orbiter Image Recovery Project. The project obtained the 1474 hours of original tapes from NASA JPL, and at NASA Ames refurbished the drives. Additionally, the demodulator system was recreated from archived documentation using modern techniques. The project digitized the 1474 tapes, processed the 20 terabyes of raw data. The process of reviving the tape drives after 45 years, redesigning the demodulator from limited information largely from engineering papers delivered in the 1960's, and the process for capturing and archiving the data will be described. The peer review is complete and the Lunar Orbiter images will be released to the planetary science community in Q3 2017.

Occupational exposure to asbestos in the drywall taping process.

PubMed

Verma, D K; Middleton, C G

1980-04-01

Studies of airborne asbestos fiber concentrations associated with various operations of the drywall taping process have been undertaken in the province of Alberta, Canada. The results show that mixing, sanding and sweeping created high levels of airborne asbestos dust. The measured concentrations were frequently in excess of occupational health standards. Sanding in particular was assessed the most hazardous operation. The results are discussed in light of present and proposed Occupational Health Standards, and in terms of its implications for other workers, household contacts, and consumer's risk. Measures to reduce and control the health hazards associated with the process are described.

The Taped Monologue as Narrative Technique for Reflective Practice

ERIC Educational Resources Information Center

Ford, Keith

2016-01-01

In this article, I describe how an EFL teacher engaged in a process of reflective practice. As she looked back on her teaching career, she explored the critical incidents, principles, and practices that have informed her present teaching identity. I focus on how a taped monologue narrative technique was used, and on the rationale, practice, and…

Process for preparing tapes from thermoplastic polymers and carbon fibers

NASA Technical Reports Server (NTRS)

Chung, Tai-Shung (Inventor); Furst, Howard (Inventor); Gurion, Zev (Inventor); McMahon, Paul E. (Inventor); Orwoll, Richard D. (Inventor); Palangio, Daniel (Inventor)

1986-01-01

The instant invention involves a process for use in preparing tapes or rovings, which are formed from a thermoplastic material used to impregnate longitudinally extended bundles of carbon fibers. The process involves the steps of (a) gas spreading a tow of carbon fibers; (b) feeding the spread tow into a crosshead die; (c) impregnating the tow in the die with a thermoplastic polymer; (d) withdrawing the impregnated tow from the die; and (e) gas cooling the impregnated tow with a jet of air. The crosshead die useful in the instant invention includes a horizontally extended, carbon fiber bundle inlet channel, means for providing melted polymer under pressure to the die, means for dividing the polymeric material flowing into the die into an upper flow channel and a lower flow channel disposed above and below the moving carbon fiber bundle, means for applying the thermoplastic material from both the upper and lower channels to the fiber bundle, and means for withdrawing the resulting tape from the die.

The influence of Kinesiology Taping on the reduction of lymphoedema among women after mastectomy – preliminary study

PubMed Central

Karczmarek-Borowska, Bożenna; Tymczak, Monika; Hałas, Ireneusz; Banaś, Joanna

2014-01-01

Introduction Kinesiology Taping is a method that assists healing processes and improves the physical efficiency. The aim of the study The aim of the study was to assess the influence of Kinesiology Taping on the lymphoedema reduction among women after mastectomy. Material and methods The subject of the research included 44 women underwent single mastectomy along with the removal of lymph nodes. The examination was carried out from the 4th of January to the 4th of February, 2013. The traditional taping method was implemented among 22 women, whereas the own taping method was used among the other 22 women. The therapy took 21 days, during which the tapes were applied three times every 7 days. The measurements were made before every application and at the end of the therapy. In the study, a questionnaire was used and it included questions concerning basic demographic, epidemiological data as well as the evaluation of the therapy effectiveness. The linear measurements of the upper limbs, the measurements of the range of joints’ motion in the upper limb were taken as well as grip strength was made. Results The reduction of the volume of lymphoedema of 55% was reported in the study group, whereas the oedema reduced by 27% in the clinical control one. Conclusions In the reduction of lymphoedema, the greater effectiveness of the own taping method in comparison to the traditional one was reported. Kinesiology Taping exerted an influence on the improvement of the upper limb's joints movability and the grip strength. PMID:24966797

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apyan, A.; Badillo, J.; Cruz, J. Diaz

The CMS experiment at the LHC relies on 7 Tier-1 centres of the WLCG to perform the majority of its bulk processing activity, and to archive its data. During the first run of the LHC, these two functions were tightly coupled as each Tier-1 was constrained to process only the data archived on its hierarchical storage. This lack of flexibility in the assignment of processing workflows occasionally resulted in uneven resource utilisation and in an increased latency in the delivery of the results to the physics community.The long shutdown of the LHC in 2013-2014 was an opportunity to revisit thismore » mode of operations, disentangling the processing and archive functionalities of the Tier-1 centres. The storage services at the Tier-1s were redeployed breaking the traditional hierarchical model: each site now provides a large disk storage to host input and output data for processing, and an independent tape storage used exclusively for archiving. Movement of data between the tape and disk endpoints is not automated, but triggered externally through the WLCG transfer management systems.With this new setup, CMS operations actively controls at any time which data is available on disk for processing and which data should be sent to archive. Thanks to the high-bandwidth connectivity guaranteed by the LHCOPN, input data can be freely transferred between disk endpoints as needed to take advantage of free CPU, turning the Tier-1s into a large pool of shared resources. The output data can be validated before archiving them permanently, and temporary data formats can be produced without wasting valuable tape resources. Lastly, the data hosted on disk at Tier-1s can now be made available also for user analysis since there is no risk any longer of triggering chaotic staging from tape.In this contribution, we describe the technical solutions adopted for the new disk and tape endpoints at the sites, and we report on the commissioning and scale testing of the service. We detail the procedures implemented by CMS computing operations to actively manage data on disk at Tier-1 sites, and we give examples of the benefits brought to CMS workflows by the additional flexibility of the new system.« less

Cooper Pair-Like Systems at High Temperature and their Role on Fluctuations Near the Critical Temperature

NASA Astrophysics Data System (ADS)

Ausloos, M.; Dorbolo, S.

A logarithmic behavior is hidden in the linear temperature regime of the electrical resistivity R(T) of some YBCO sample below 2Tc where "pairs" break apart, fluctuations occur and "a gap is opening". An anomalous effect also occurs near 200 K in the normal state Hall coefficient. In a simulation of oxygen diffusion in planar 123 YBCO, an anomalous behavior is found in the oxygen-vacancy motion near such a temperature. We claim that the behavior of the specific heat above and near the critical temperature should be reexamined in order to show the influence and implications of fluctuations and dimensionality on the nature of the phase transition and on the true onset temperature.

The effect of temperature cycling typical of low earth orbit satellites on thin films of YBa2Cu3O(7-x)

NASA Technical Reports Server (NTRS)

Mogro-Campero, A.; Turner, L. G.; Bogorad, A.; Herschitz, R.

1990-01-01

The refrigeration of superconductors in space poses a challenging problem. The problem could be less severe if superconducting materials would not have to be cooled when not in use. Thin films of the YBa2Cu3O(7-x) (YBCO) superconductor were subjected to thermal cycling, which was carried out to simulate a large number of eclipses of a low earth orbit satellite. Electrical measurements were performed to find the effect of the temperature cycling. Thin films of YBCO were formed by coevaporation of Y, BaF2, and Cu and postannealing in wet oxygen at 850 C for 3.5 h. The substrates used were (100) SrTiO3, polycrystalline alumina, and oxidized silicon; the last two have an evaporated zirconia layer. Processing and microstructure studies of these types of films have been published. THe zero resistance transition temperatures of the samples used in this study were 91, 82, and 86 K, respectively. The samples were characterized by four point probe electrical measurements as a function of temperature. The parameters measured were: the zero resistance transition temperature, the 10 to 90 percent transition width, and the room temperature resistance, normalized to that measured before temperature cycling. The results for two samples are presented. Each sample had a cumulative exposure. Cycling in atmospheric pressure nitrogen was performed at a rate of about 60 cycles per day, whereas in vacuum the rate was only about 10 cycles per day. The results indicate only little or no changes in the parameters measured. Degradation of superconducting thin films of YBCO has been reported due to storage in nitrogen. It is believed that the relatively good performance of films after temperature cycling is related to the fact that BaF2 was used as an evaporation source. The latest result on extended temperature cycling indicates significant degradation. Further tests of extended cycling will be carried out to provide additional data and to clarify this preliminary finding.

In-situ diagnostics for metalorganic chemical vapor deposition of yttrium barium copper oxide

NASA Astrophysics Data System (ADS)

Tripathi, Ashok Burton

A new stagnation flow MOCVD research reactor is described that is designed to serve as a testbed to develop tools for "intelligent" thin film deposition, such as in-situ sensors and diagnostics, control algorithms, and thin film growth models. The reactor is designed in particular for the deposition of epitaxial YBa2Cu3O 7-delta on MgO, although with minor modifications it would be suitable for deposition of any metal-oxide thin films. The reactor is specifically designed to permit closed-loop thermal and stoichiometric control of the film growth process. Closed-loop control of precursor flow rates is accomplished by using ultraviolet absorption spectroscopy on each precursor line. Also integrated into the design is a Fourier Transform Infrared (FTIR) spectroscopy system which collects real-time, in-situ infrared polarized reflectance spectra of the film as it grows. Numerical simulation was used extensively to optimize the fluid dynamics and heat transfer to provide uniform fluxes to the substrate. As a result, thickness uniformity across the substrate is typically within 3% from the center to the edge of the substrate. Experimental studies of thin films grown in the Y/Ba/Cu/O system have been carried out. The films have been characterized by Rutherford Backscattering Spectrometry and X-ray Diffraction. Results indicate c-axis oriented grains with pure 1:2:3 phase YBCO, good spatial uniformity, and a low degree of c-axis wobble. Experimental growth data is used in a gas phase and surface chemistry model to calculate sticking coefficients for yttrium oxide, barium oxide, and copper oxide on YBCO. In-situ FTIR and Coherent Gradient Sensing (CGS) analysis of growing films has been performed, yielding accurate substrate temperature, film thickness monitoring, and full-field, real-time curvature maps of the films. In addition, we have implemented CGS to obtain full-field in-situ images of local curvature during oxygenation and deoxygenation of YBCO films. An analysis of the oxygen diffusion is performed, and diffusivity constants are presented for a variety of temperature and film conditions.

Preschool Children's Comprehension of a "Sesame Street" Video Tape: The Effects of Repeated Viewing and Previewing Instructions.

ERIC Educational Resources Information Center

Sell, Marie A.; And Others

1995-01-01

Twenty male and 20 female 4-year olds viewed a 19-minute "Sesame Street" videotape once a week for 3 weeks to determine whether comprehension would improve if time was given to "process" the tape and if instructions were previewed. Findings indicate that repeated viewing was most important in comprehension; previewing…

An Infrared Data Acquisition and Processing System

DTIC Science & Technology

1977-09-01

Display Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Terminai High Speed Printer/Plotter . . . . Digital Tape Unit...In addition to the recently procured Honeywell Model 96 analog re- corder, a High Density digital tape unit is planned. This unit will increase the...diagram of Figure 1 we see that a Digital Equipment Corp. (DEC) PDP-11/15 minicomputer with 28K of core memory drives the digital section of IRDAPS

Software Computes Tape-Casting Parameters

NASA Technical Reports Server (NTRS)

deGroh, Henry C., III

2003-01-01

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.

Testing of machine wound second generation HTS tape Vacuum Pressure Impregnated coils

NASA Astrophysics Data System (ADS)

Swaffield, D.; Lewis, C.; Eugene, J.; Ingles, M.; Peach, D.

2014-05-01

Delamination of second generation (2G) High Temperature Superconducting (HTS) tapes has previously been reported when using resin based insulation systems for wound coils. One proposed root cause is the differential thermal contraction between the coil former and the resin encapsulated coil turns resulting in the tape c-axis tensile stress being exceeded. Importantly, delamination results in unacceptable degradation of the superconductor critical current level. To mitigate the delamination risk and prove winding, jointing and Vacuum Pressure Impregnation (VPI) processes in the production of coils for superconducting rotating machines at GE Power Conversion two scaled trial coils have been wound and extensively tested. The coils are wound from 12mm wide 2G HTS tape supplied by AMSC onto stainless steel 'racetrack' coil formers. The coils are wound in two layers which include both in-line and layer-layer joints subject to in-process test. The resin insulation system chosen is VPI and oven cured. Tests included; insulation resistance, repeat quench and recovery of the superconductor, heat runs and measurement of n-value, before and after multiple thermal cycling between ambient and 35 Kelvin. No degradation of coil performance is evidenced.

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes.

PubMed

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-03-25

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 10(4) A/cm(2) in 10 T and 4.3 × 10(4) A/cm(2) in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications.

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes

PubMed Central

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-01-01

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 104 A/cm2 in 10 T and 4.3 × 104 A/cm2 in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications. PMID:24663054

Strongly enhanced current densities in Sr0.6K0.4Fe2As2 + Sn superconducting tapes

NASA Astrophysics Data System (ADS)

Lin, He; Yao, Chao; Zhang, Xianping; Zhang, Haitao; Wang, Dongliang; Zhang, Qianjun; Ma, Yanwei; Awaji, Satoshi; Watanabe, Kazuo

2014-03-01

Improving transport current has been the primary topic for practical application of superconducting wires and tapes. However, the porous nature of powder-in-tube (PIT) processed iron-based tapes is one of the important reasons for low critical current density (Jc) values. In this work, the superconducting core density of ex-situ Sr0.6K0.4Fe2As2 + Sn tapes, prepared from optimized precursors, was significantly improved by employing a simple hot pressing as an alternative route for final sintering. The resulting samples exhibited optimal critical temperature (Tc), sharp resistive transition, small resistivity and high Vickers hardness (Hv) value. Consequently, the transport Jc reached excellent values of 5.1 × 104 A/cm2 in 10 T and 4.3 × 104 A/cm2 in 14 T at 4.2 K, respectively. Our tapes also exhibited high upper critical field Hc2 and almost field-independent Jc. These results clearly demonstrate that PIT pnictide wire conductors are very promising for high-field magnet applications.

Analysis of particulates on tape lift samples

NASA Astrophysics Data System (ADS)

Moision, Robert M.; Chaney, John A.; Panetta, Chris J.; Liu, De-Ling

2014-09-01

Particle counts on tape lift samples taken from a hardware surface exceeded threshold requirements in six successive tests despite repeated cleaning of the surface. Subsequent analysis of the particle size distributions of the failed tests revealed that the handling and processing of the tape lift samples may have played a role in the test failures. In order to explore plausible causes for the observed size distribution anomalies, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to perform chemical analysis on collected particulates. SEM/EDX identified Na and S containing particles on the hardware samples in a size range identified as being responsible for the test failures. ToF-SIMS was employed to further examine the Na and S containing particulates and identified the molecular signature of sodium alkylbenzene sulfonates, a common surfactant used in industrial detergent. The root cause investigation suggests that the tape lift test failures originated from detergent residue left behind on the glass slides used to mount and transport the tape following sampling and not from the hardware surface.

A combinaison of UV curing technology with ATL process

NASA Astrophysics Data System (ADS)

Balbzioui, I.; Hasiaoui, B.; Barbier, G.; L'hostis, G.; Laurent, F.; Ibrahim, A.; Durand, B.

2017-10-01

In order to reduce the time and the cost of manufacturing composite, UV curing technology combined with automated tape placement process (ATL) based on reverse approach by working with a fixed head was studied in this article. First, a brief description of the developed head placement is presented. Mechanical properties are then evaluated by varying process parameters, including compaction force and tape placement speed. Finally, a parametric study is carried out to identify suitable materials and process parameters to manufacture a photo composite material with high mechanical performances. The obtained results show that UV curing is a very good alternative for thermal polymerization because of its fast cure speed due to less dependency on temperature.

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 6: Specification for EOS Central Data Processing Facility (CDPF)

NASA Technical Reports Server (NTRS)

1974-01-01

The specifications and functions of the Central Data Processing (CDPF) Facility which supports the Earth Observatory Satellite (EOS) are discussed. The CDPF will receive the EOS sensor data and spacecraft data through the Spaceflight Tracking and Data Network (STDN) and the Operations Control Center (OCC). The CDPF will process the data and produce high density digital tapes, computer compatible tapes, film and paper print images, and other data products. The specific aspects of data inputs and data processing are identified. A block diagram of the CDPF to show the data flow and interfaces of the subsystems is provided.

Magnetic Tape Recording

NASA Technical Reports Server (NTRS)

Athey, Skipwith W.

1966-01-01

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.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stubblefield, M.A.; Yang, C.; Lea, R.H.

The use of heat-activated thermal couplings is a quick and cost-effective joining method for composite-to-composite materials. In this study, a prepreg laminate which contains thermoset resins and fiberglass reinforcements is wrapped around the ends of components which are to be joined. A shrink tape, made of thermoplastic material, is placed over the prepreg laminate. When curing the shrink tape and the prepreg laminate, the shrink tape shrinks and compresses the prepreg to obtain good adhesion and the required mechanical properties. The mechanical strength of the heat coupling joint in bending increased by 29% over the currently used butt-weld method. Tomore » optimize the curing process, a finite element model was also developed to show the temperature distribution of the heat coupling joint during the curing process. Based on the tested prepreg material properties and model, the finite analysis temperature distribution differed less than 10% from that of the experimental data.« less

General purpose film plotting system

NASA Technical Reports Server (NTRS)

Mcquillan, C.

1977-01-01

The general purpose film plotting system which is a plot program design to handle a majority of the data tape formats presently available under OS/360 was discussed. The convenience of this program is due to the fact that the user merely describes the format of his data set and the type of data plots he desires. It processes the input data according to the given specifications. The output is generated on a tape which yields data plots when processed by the selected plotter. A summary of each job is produced on the printer.

A novel, two-step top seeded infiltration and growth process for the fabrication of single grain, bulk (RE)BCO superconductors

NASA Astrophysics Data System (ADS)

Namburi, Devendra K.; Shi, Yunhua; Palmer, Kysen G.; Dennis, Anthony R.; Durrell, John H.; Cardwell, David A.

2016-09-01

A fundamental requirement of the fabrication of high performing, (RE)-Ba-Cu-O bulk superconductors is achieving a single grain microstructure that exhibits good flux pinning properties. The top seeded melt growth (TSMG) process is a well-established technique for the fabrication of single grain (RE)BCO bulk samples and is now applied routinely by a number of research groups around the world. The introduction of a buffer layer to the TSMG process has been demonstrated recently to improve significantly the general reliability of the process. However, a number of growth-related defects, such as porosity and the formation of micro-cracks, remain inherent to the TSMG process, and are proving difficult to eliminate by varying the melt process parameters. The seeded infiltration and growth (SIG) process has been shown to yield single grain samples that exhibit significantly improved microstructures compared to the TSMG technique. Unfortunately, however, SIG leads to other processing challenges, such as the reliability of fabrication, optimisation of RE2BaCuO5 (RE-211) inclusions (size and content) in the sample microstructure, practical oxygenation of as processed samples and, hence, optimisation of the superconducting properties of the bulk single grain. In the present paper, we report the development of a near-net shaping technique based on a novel two-step, buffer-aided top seeded infiltration and growth (BA-TSIG) process, which has been demonstrated to improve greatly the reliability of the single grain growth process and has been used to fabricate successfully bulk, single grain (RE)BCO superconductors with improved microstructures and superconducting properties. A trapped field of ˜0.84 T and a zero field current density of 60 kA cm-2 have been measured at 77 K in a bulk, YBCO single grain sample of diameter 25 mm processed by this two-step BA-TSIG technique. To the best of our knowledge, this value of trapped field is the highest value ever reported for a sample fabricated by an infiltration and growth process. In this study we report the successful fabrication of 14 YBCO samples, with diameters of up to 32 mm, by this novel technique with a success rate of greater than 92%.

The role of a-axis grains in the transition to the normal state of YBa{sub 2}Cu{sub 3}O{sub 7−δ} films and of 2G-coated conductors when induced by high electrical current densities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, P., E-mail: pierre.bernstein@ensicaen.fr; Harnois, C.; Mc Loughlin, C.

The influence of surface defects, in particular of a-axis grains, on the transition to the normal state induced by high current densities in YBa{sub 2}Cu{sub 3}O{sub 7−δ} (YBCO) thin films and in a commercial 2G-coated conductor is investigated. For that purpose, the surface of the samples is observed by scanning electron microscopy and isothermal current-voltage curves are measured at different temperatures with pulsed currents up to the quenching value I*. The results show that the ratio of I* to the critical current is large if a-axis grains are not visible at the surface of the YBCO films, while it ismore » much lower if the surface includes a-axis grains as this is the case for the coated conductor. The connection between the transition onset and the vortex dynamics, as well as the role of the a-axis grains in this process are discussed. The relation between the I* values obtained from thermal calculations and those resulting from vortex dynamics considerations is also discussed, as well as the possible consequences suggested by this work for the different applications of the coated conductors.« less

Disentangling vortex pinning landscape in chemical solution deposited superconducting YBa2Cu3O7-x films and nanocomposites

NASA Astrophysics Data System (ADS)

Palau, A.; Vallès, F.; Rouco, V.; Coll, M.; Li, Z.; Pop, C.; Mundet, B.; Gàzquez, J.; Guzman, R.; Gutierrez, J.; Obradors, X.; Puig, T.

2018-07-01

In-field angular pinning performances at different temperatures have been analysed on chemical solution deposited (CSD) YBa2Cu3O7-x (YBCO) pristine films and nanocomposites. We show that with this analysis we are able to quantify the vortex pinning strength and energies, associated with different kinds of natural and artificial pinning defects, acting as efficient pinning centres at different regions of the H-T phase diagram. A good quantification of the variety of pinning defects active at different temperatures and magnetic fields provides a unique tool to design the best vortex pinning landscape under different operating conditions. We have found that by artificially introducing a unique defect in the YBCO matrix, the stacking faults, we are able to modify three different contributions to vortex pinning (isotropic-strong, anisotropic-strong, and isotropic-weak). The isotropic-strong contribution, widely studied in CSD YBCO nanocomposites, is associated with nanostrained regions induced at the partial dislocations surrounding the stacking faults. Moreover, the stacking fault itself acts as a planar defect which provides a very effective anisotropic-strong pinning at H//ab. Finally, the large presence of Cu-O cluster vacancies found in the stacking faults have been revealed as a source of isotropic-weak pinning sites, very active at low temperatures and high fields.

Design of a cryogenic system for a 20m direct current superconducting MgB2 and YBCO power cable

NASA Astrophysics Data System (ADS)

Cheadle, Michael J.; Bromberg, Leslie; Jiang, Xiaohua; Glowacki, Bartek; Zeng, Rong; Minervini, Joseph; Brisson, John

2014-01-01

The Massachusetts Institute of Technology, the University of Cambridge in the United Kingdom, and Tsinghua University in Beijing, China, are collaborating to design, construct, and test a 20 m, direct current, superconducting MgB2 and YBCO power cable. The cable will be installed in the State Key Laboratory of Power Systems at Tsinghua University in Beijing beginning in 2013. In a previous paper [1], the cryogenic system was briefly discussed, focusing on the cryogenic issues for the superconducting cable. The current paper provides a detailed discussion of the design, construction, and assembly of the cryogenic system and its components. The two-stage system operates at nominally 80 K and 20 K with the primary cryogen being helium gas. The secondary cryogen, liquid nitrogen, is used to cool the warm stage of binary current leads. The helium gas provides cooling to both warm and cold stages of the rigid cryostat housing the MgB2 and YBCO conductors, as well as the terminations of the superconductors at the end of the current leads. A single cryofan drives the helium gas in both stages, which are thermally isolated with a high effectiveness recuperator. Refrigeration for the helium circuit is provided by a Sumitomo RDK415 cryocooler. This paper focuses on the design, construction, and assembly of the cryostat, the recuperator, and the current leads with associated superconducting cable terminations.

Test Status for Proposed Coupling of a Gravitational Force to Extreme Type II YBCO Ceramic Superconductors

NASA Technical Reports Server (NTRS)

Noever, David; Li, Ning; Robertson, Tony; Koczor, Ron; Brantley, Whitt

1999-01-01

As a Bose condensate, superconductors provide novel conditions for revisiting previously proposed couplings between electromagnetism and gravity. Strong variations in Cooper pair electron density, large conductivity and low magnetic permeability define superconductive and degenerate condensates without the traditional density limits imposed by the Fermi energy (about 10-6 g/cu cm). Recent experiments have reported anomalous weight loss for a test mass suspended above a rotating Type II, YBCO superconductor, with the percentage change (0.05-2.1%) independent of the test mass' chemical composition and diamagnetic properties. A variation of 5 parts per 10(exp 4) was reported above a stationary (non-rotating) superconductor. In the present experiments reported using a sensitive gravimeter (resolution <10(exp -9) unit gravity or variation of 10(exp -6) cm/sq s in accelerations), bulk YBCO superconductors were stably levitated in a DC magnetic field (0.6 Tesla) subject to lateral AC fields (60 Gauss at 60 Hz) and rotation. With magnetic shielding, thermal control and buoyancy compensation, changes in acceleration were measured to be less than 2 parts in 10(exp 8) of the normal gravitational acceleration. This result puts new limits on the strength and range of the proposed coupling between high-Tc superconductors and gravity. Latest test results will be reported, along with status for future improvements and prospects.

Non-contact inline monitoring of thermoplastic CFRP tape quality using air-coupled ultrasound

NASA Astrophysics Data System (ADS)

Essig, W.; Fey, P.; Meiler, S.; Kreutzbruck, M.

2017-02-01

Beginning with the aerospace industry, fiber reinforced plastics have spread towards many applications such as automotive, civil engineering as well as sports and leisure articles. Their superior strength and stiffness to mass ratio made them the number one material for achieving high performance. Especially continuous fiber reinforced plastics allow for the construction of structures which are custom tailored to their mechanical loads by adjusting the paths of the fibers to the loading direction. The two main constituents of CFRP are carbon fibers and matrix. Two possibilities for matrix material exist: thermosetting and thermoplastic matrix. While thermosetting matrix may yield better properties with respect to thermal loads, thermoplasticity opens a wide range of applications due to weldability, shapeability, and compatibility to e.g. injection molded thermoplastic materials. Thin (0.1 mm) thermoplastic continuous fiber CFRP tapes with a width of 100 mm were examined using air-coupled ultrasound. Transducers were arranged in reflection as well as transmission setup. By slanted incidence of the ultrasound on the tape surface, guided waves were excited in the material in fiber direction and perpendicular to the fiber direction. Artificial defects - fiber cuts, matrix cuts, circular holes, low velocity impacts from tool drop, and sharp bends - were produced. Experiments on a stationary tape showed good detectability of all artificial defects by guided waves. Also the effects of variation in material properties, fiber volume content and fiber matrix adhesion being the most relevant, on guided wave propagation were examined, to allow for quality assessment. Guided wave measurements were supported by destructive analysis. Also an apparatus containing one endless loop of CFRP tape was constructed and built to simulate inline testing of CFRP tapes, as it would be employed in a CFRP tape production environment or at a CFRP tape processing facility. The influences of tape conveying speed on detectability of artificial defects as well as material properties were elaborated and recommendations for implementation in production scale inline monitoring are given.

An experimental investigation on the thermal field of overlapping layers in laser-assisted tape winding process

NASA Astrophysics Data System (ADS)

Hosseini, S. M. A.; Baran, I.; Akkerman, R.

2018-05-01

The laser-assisted tape winding (LATW) is an automated process for manufacturing fiber-reinforced thermoplastic tubular products, such as pipes and pressure vessels. Multi-physical phenomena such as heat transfer, mechanical bonding, phase changes and solid mechanics take place during the process. These phenomena need to be understood and described well for an improved product reliability. Temperature is one of the important parameters in this process to control and optimize the product quality which can be employed in an intelligent model-based inline control system. The incoming tape can overlap with the already wounded layer during the process based on the lay-up configuration. In this situation, the incoming tape can step-on or step-off to an already deposited layer/laminate. During the overlapping, the part temperature changes due to the variation of the geometry caused by previously deposited layer, i.e. a bump geometry. In order to qualify the temperature behavior at the bump regions, an experimental set up is designed on a flat laminate. Artificial bumps/steps are formed on the laminate with various thicknesses and fiber orientations. As the laser head experiences the step-on and step-off, the IR (Infra-Red) camera and the embedded thermocouples measure the temperature on the surface and inside the laminate, respectively. During the step-on, a small drop in temperature is observed while in step-off a higher peak in temperature is observed. It can be concluded that the change in the temperature during overlapping is due to the change in laser incident angle made by the bump geometry. The effect of the step thickness on the temperature peak is quantified and found to be significant.

Microstructure and trapped field of YBCO bulk single-grain superconductors prepared by interior seeding

NASA Astrophysics Data System (ADS)

Radusovska, M.; Diko, P.; Piovarci, S.; Park, S.-D.; Jun, B.-H.; Kim, C.-J.

2017-10-01

The microstructural analyses of YBCO bulk single-grain superconductors grown by interior seeding with taller and shorter upper pellets have shown that a suitable upper pellet height can lower the porosity in the upper part of the sample, produce a more appropriate distribution of pinning centres in the form of Y-211 particles and suppress subgrain formation with a higher crystal misalignment in the c-growth sector (c-GS), which can lead to a higher measured trapped magnetic field and a more uniform cone of the trapped-field profile. The observed bulging of the sample surface at the c-GS can be explained by the edge melt distribution model, which shows that macroscopic mass transport to the growth sector occurs with higher growth rates.

Oxygen desorption from YBa2Cu3O(7-x) and Bi2CaSr2Cu2O(8 + delta) superconductors

NASA Technical Reports Server (NTRS)

Mesarwi, A.; Levenson, L. L.; Ignatiev, A.

1991-01-01

Oxygen desorption experiments from YBa2Cu3O(7-x) (YBCO) and Bi2CaSr2Cu2O(8 + delta) (BSCCO) superconductors were carried out using a quadrupole mass spectrometer for monitoring the desorbing species and X-ray photoemission spectroscopy for surface characterization. Molecular oxygen was found to desorb from both superconductors following photoirradiation with ultraviolet/optical radiation and subsequent heating at over 150 C. Both YBCO and BSCCO were found to have similar oxygen desorption rates and similar activation energies. The desorption data as well as the X-ray photoemission data indicate that the oxygen desorption is not intrinsic to the superconductors but rather due to molecular oxygen entrapped in the material.

Theory of the vortex matter transformations in high-Tc superconductor YBCO.

PubMed

Li, Dingping; Rosenstein, Baruch

2003-04-25

Flux line lattice in type II superconductors undergoes a transition into a "disordered" phase such as vortex liquid or vortex glass, due to thermal fluctuations and random quenched disorder. We quantitatively describe the competition between the thermal fluctuations and the disorder using the Ginzburg-Landau approach. The following T-H phase diagram of YBCO emerges. There are just two distinct thermodynamical phases, the homogeneous and the crystalline one, separated by a single first order transition line. The line, however, makes a wiggle near the experimentally claimed critical point at 12 T. The "critical point" is reinterpreted as a (noncritical) Kauzmann point in which the latent heat vanishes and the line is parallel to the T axis. The magnetization, the entropy, and the specific heat discontinuities at melting compare well with experiments.

Numerical modeling of laser assisted tape winding process

NASA Astrophysics Data System (ADS)

Zaami, Amin; Baran, Ismet; Akkerman, Remko

2017-10-01

Laser assisted tape winding (LATW) has become more and more popular way of producing new thermoplastic products such as ultra-deep sea water riser, gas tanks, structural parts for aerospace applications. Predicting the temperature in LATW has been a source of great interest since the temperature at nip-point plays a key role for mechanical interface performance. Modeling the LATW process includes several challenges such as the interaction of optics and heat transfer. In the current study, numerical modeling of the optical behavior of laser radiation on circular surfaces is investigated based on a ray tracing and non-specular reflection model. The non-specular reflection is implemented considering the anisotropic reflective behavior of the fiber-reinforced thermoplastic tape using a bidirectional reflectance distribution function (BRDF). The proposed model in the present paper includes a three-dimensional circular geometry, in which the effects of reflection from different ranges of the circular surface as well as effect of process parameters on temperature distribution are studied. The heat transfer model is constructed using a fully implicit method. The effect of process parameters on the nip-point temperature is examined. Furthermore, several laser distributions including Gaussian and linear are examined which has not been considered in literature up to now.

Characterization of silicon-gate CMOS/SOS integrated circuits processed with ion implantation

NASA Technical Reports Server (NTRS)

Woo, D. S.

1982-01-01

The procedure used to generate MEBES masks and produce test wafers from the 10X Mann 1600 Pattern Generator Tape using existing CAD utility programs and the MEBES machine in the RCA Solid State Technology Center are described. The test vehicle used is the MSFC-designed SC102 Solar House Timing Circuit. When transforming the Mann 1600 tapes into MEBES tapes, extreme care is required in order to obtain accurate minimum linewidths when working with two different coding systems because the minimum grid sizes may be different for the two systems. The minimum grid sizes are 0.025 mil for MSFC Mann 1600 and 0.02 mil for MEBES. Some snapping to the next grid is therefore inevitable, and the results of this snapping effect are significant when submicron lines are present. However, no problem was noticed in the SC102 circuit because its minimum linewidth is 0.3 mil (7.6 microns). MEBES masks were fabricated and wafers were processed using the silicon-gate CMOS/SOS and aluminum-gate COS/MOS processing.

Pressure Sensitive Tape in the Manufacture of Reusable Solid Rocket Motors

NASA Technical Reports Server (NTRS)

Champneys, Jeff

2007-01-01

ATK Launch Systems Inc. manufactures the reusable solid rocket motor (RSRM) for NASA's Space Shuttle program. They are used in pairs to launch the Space Shuttle. Pressure sensitive tape (PST) is used throughout the RSRM manufacturing process. A few PST functions are: 1) Secure labels; 2) Provide security seals; and 3) Protect tooling and flight hardware during various inert and live operations. Some of the PSTs used are: Cloth, Paper, Reinforced Teflon, Double face, Masking, and Vinyl. Factors given consideration for determining the type of tape to be used are: 1) Ability to hold fast; 2) Ability to release easily; 3) Ability to endure abuse; 4) Strength; and 5) Absence of adhesive residue after removal.

Induction Bonding of Prepreg Tape and Titanium Foil

NASA Technical Reports Server (NTRS)

Messier, Bernadette C.; Hinkley, Jeffrey A.; Johnston, Norman J.

1998-01-01

Hybrid structural laminates made of titanium foil and carbon fiber reinforced polymer composite offer a potential for improved performance in aircraft structural applications. To obtain information needed for the automated fabrication of hybrid laminates, a series of bench scale tests were conducted of the magnetic induction bonding of titanium foil and thermoplastic prepreg tape. Foil and prepreg specimens were placed in the gap of a toroid magnet mounted in a bench press. Several magnet power supplies were used to study power at levels from 0.5 to 1.75 kW and frequencies from 50 to 120 kHz. Sol-gel surface-treated titanium foil, 0.0125 cm thick, and PIXA/IM7 prepreg tape were used in several lay-up configurations. Data were obtained on wedge peel bond strength, heating rate, and temperature ramp over a range of magnet power levels and frequencies at different "power-on" times for several magnet gap dimensions. These data will be utilized in assessing the potential for automated processing. Peel strengths of foil-tape bonds depended on the maximum temperature reached during heating and on the applied pressure. Maximum peel strengths were achieved at 1.25kW and 8OkHz. Induction heating of the foil appears to be capable of good bonding up to 10 plies of tape. Heat transfer calculations indicate that a 20-40 C temperature difference exists across the tape thickness during heat-up.

Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

DOE PAGES

Majoros, M.; Sumption, M. D.; Collings, E. W.; ...

2015-04-08

A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand I c. At a strand current of 1.3I c about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s -1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3I c) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb 3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

DOE PAGES

sumption, Mike; Majoros, Milan; Collings, E. W.; ...

2014-11-07

A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand I c. At a strand current of 1.3I c about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s -1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3I c ) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb 3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

DOE Office of Scientific and Technical Information (OSTI.GOV)

Majoros, M.; Sumption, M. D.; Collings, E. W.

A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand I c. At a strand current of 1.3I c about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s -1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3I c) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb 3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

Inter-strand current sharing and ac loss measurements in superconducting YBCO Roebel cables

DOE Office of Scientific and Technical Information (OSTI.GOV)

sumption, Mike; Majoros, Milan; Collings, E. W.

A Roebel cable, one twist pitch long, was modified from its as-received state by soldering copper strips between the strands to provide inter-strand connections enabling current sharing. Various DC transport currents (representing different percentages of its critical current) were applied to a single strand of such a modified cable at 77 K in a liquid nitrogen bath. Simultaneous monitoring of I–V curves in different parts of the strand as well as in its interconnections with other strands was made using a number of sensitive Keithley nanovoltmeters in combination with a multichannel high-speed data acquisition card, all controlled via LabView software.more » Current sharing onset was observed at about 1.02 of strand I c. At a strand current of 1.3I c about 5% of the current was shared through the copper strip interconnections. A finite element method modeling was performed to estimate the inter-strand resistivities required to enable different levels of current sharing. The relative contributions of coupling and hysteretic magnetization (and loss) were compared, and for our cable and tape geometry, and at dB/dt=1 T s -1, and our inter-strand resistance of 0.77 mΩ, (enabling a current sharing of 5% at 1.3I c ) the coupling component was 0.32% of the hysteretic component. However, inter-strand contact resistance values of 100–1000 times smaller (close to those of NbTi and Nb 3Sn based accelerator cables) would make the coupling components comparable in size to the hysteretic components.« less

Improving the Useability of the Defense Mapping Agency Digital Feature Analysis Data for Training Simulator Applications.

DTIC Science & Technology

1982-09-01

would be merged and a corrected output tape could be generated to 21 I 47 be used as a replacement for the original tape. A diagram of the system designed...overview of all of the procedures involved In an error correction session. The process flow is depicted in the configuration diagram provided in Figure... Roundhouse . .. ....................... 224 Roads (General) ......................... 240 Elevated. .... ...................... 244 Causeways

Directly Connecting the Very Long Baseline Array

NASA Astrophysics Data System (ADS)

Hunt, Gareth; Romney, Jonathan D.; Walker, R. Craig

At present, the signals received by the 10 antennas of the Very Long Baseline Array (VLBA) are recorded on instrumentation tapes. These tapes are then shipped from the antenna locations --- distributed across the mainland USA, the US Virgin Islands, and Hawaii --- to the processing center in Socorro, New Mexico. The Array operates today at a mean sustained data rate of 128 Mbps per antenna, but peak rates of 256 Mbps and 512 Mbps are also used. Transported tapes provide the cheapest method of attaining these bit rates. The present tape system derives from wideband recording techniques dating back to the late 1970s, and has been in use since the commissioning of the VLBA in 1993. It is in need of replacement on a time scale of a few years. Further, plans are being developed which would increase the required data rates to 1 Gbps in five years and 100 Gbps in ten years. With the advent of higher performance networks, it should be possible to transmit the data directly to the processing center. However, achieving this connectivity is severely complicated by the remoteness of the antennas --- ``the last mile problem.'' In addition, it is not clear that the data rates involved can be obtained at a reasonable cost.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeo, Reuben J.; Dwivedi, Neeraj; Bhatia, Charanjit S., E-mail: elebcs@nus.edu.sg

Pole tip recession (PTR) is one of the major issues faced in magnetic tape storage technology, which causes an increase in the magnetic spacing and hence signal loss during data readback. Despite efforts to reduce the magnetic spacing, PTR, and surface wear on the heads by using protective overcoats, most of them either employ complex fabrication processes and approaches do not provide adequate protection to the head or are too thick (∼10–20 nm), especially for future high density tape storage. In this work, we discuss an approach to reduce the PTR and surface wear at the head by developing an ultrathinmore » ∼7 nm bilayer overcoat of silicon/silicon nitride (Si/SiN{sub x}) and carbon (C), which is totally fabricated by a cost-effective and industrial-friendly magnetron sputtering process. When compared with a monolithic C overcoat of similar thickness, the electrically insulating Si/SiN{sub x}/C bilayer overcoat was found to provide better wear protection for commercial tape heads, as demonstrated by Auger electron spectroscopic analyses after wear tests with commercial tape media. Although the microstructures of carbon in the monolithic and bilayer overcoats were similar, the improved wear durability of the bilayer overcoat was attributed to the creation of extensive interfacial bonding of Si and N with the C overcoat and the alumina-titanium carbide composite head substrate, as predicted by time-of-flight secondary ion mass spectrometry and confirmed by in-depth X-ray photoelectron spectroscopy analyses. This study highlights the pivotal role of enhanced interfaces and interfacial bonding in developing ultrathin yet wear-durable overcoats for tape heads.« less

Flexible storage medium for write-once optical tape

NASA Technical Reports Server (NTRS)

Strandjord, Andrew J. G.; Webb, Steven P.; Perettie, Donald J.; Cipriano, Robert A.

1993-01-01

A write-once data storage media was developed which is suitable for optical tape applications. The media is manufactured using a continuous film process to deposit a ternary alloy of tin, bismuth, and copper. This laser sensitive layer is sputter deposited onto commercial plastic web as a single-layer thin film. A second layer is sequentially deposited on top of the alloy to enhance the media performance and act as an abrasion resistant hard overcoat. The media was observed to have laser write sensitivities of less than 2.0 njoules/bit, carrier-to-noise levels of greater than 50dB's, modulation depths of approximately 100 percent, read-margins of greater than 35, uniform grain sizes of less than 200 Angstroms, and a media lifetime that exceeds 10 years. Prototype tape media was produced for use in the CREO drive system. The active and overcoat materials are first sputter deposited onto three mil PET film in a single pass through the vacuum coating system, and then converted down into multiple reels of 35mm x 880m tape. One mil PET film was also coated in this manner and then slit and packaged into 3480 tape cartridges.

{bold {ital In situ}} measurements of texture and phase development in (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}{endash}Ag tapes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thurston, T.R.; Haldar, P.; Wang, Y.L.

Hard x-rays from a synchrotron source were utilized in diffraction experiments performed at elevated temperatures (up to {approximately}870{degree}C) on (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} (Bi-2223) tapes {ital completely} encased in silver. The general behavior of the phase and texture development under typical processing conditions was determined, and the effects that several variations in processing conditions had on the phase and texture development were examined. These results and their implications for improving processing conditions are discussed. {copyright} {ital 1997 Materials Research Society.}

Superconductivity devices: Commercial use of space

NASA Technical Reports Server (NTRS)

Haertling, Gene; Furman, Eugene; Hsi, Chi-Shiung; Li, Guang

1993-01-01

The processing and screen printing of the superconducting BSCCO and 123 YBCO materials on substrates is described. The resulting superconducting properties and the use of these materials as possible electrode materials for ferroelectrics at 77 K are evaluated. Also, work performed in the development of solid-state electromechanical actuators is reported. Specific details include the fabrication and processing of high strain PBZT and PLZT electrostrictive materials, the development of PSZT and PMN-based ceramics, and the testing and evaluation of these electrostrictive materials. Finally, the results of studies on a new processing technology for preparing piezoelectric and electrostrictive ceramic materials are summarized. The process involves a high temperature chemical reduction which leads to an internal pre-stressing of the oxide wafer. These reduced and internally biased oxide wafers (RAINBOW) can produce bending-mode actuator devices which possess a factor of ten more displacement and load bearing capacity than present-day benders.

Pooling the resources of the CMS Tier-1 sites

DOE PAGES

Apyan, A.; Badillo, J.; Cruz, J. Diaz; ...

2015-12-23

The CMS experiment at the LHC relies on 7 Tier-1 centres of the WLCG to perform the majority of its bulk processing activity, and to archive its data. During the first run of the LHC, these two functions were tightly coupled as each Tier-1 was constrained to process only the data archived on its hierarchical storage. This lack of flexibility in the assignment of processing workflows occasionally resulted in uneven resource utilisation and in an increased latency in the delivery of the results to the physics community.The long shutdown of the LHC in 2013-2014 was an opportunity to revisit thismore » mode of operations, disentangling the processing and archive functionalities of the Tier-1 centres. The storage services at the Tier-1s were redeployed breaking the traditional hierarchical model: each site now provides a large disk storage to host input and output data for processing, and an independent tape storage used exclusively for archiving. Movement of data between the tape and disk endpoints is not automated, but triggered externally through the WLCG transfer management systems.With this new setup, CMS operations actively controls at any time which data is available on disk for processing and which data should be sent to archive. Thanks to the high-bandwidth connectivity guaranteed by the LHCOPN, input data can be freely transferred between disk endpoints as needed to take advantage of free CPU, turning the Tier-1s into a large pool of shared resources. The output data can be validated before archiving them permanently, and temporary data formats can be produced without wasting valuable tape resources. Lastly, the data hosted on disk at Tier-1s can now be made available also for user analysis since there is no risk any longer of triggering chaotic staging from tape.In this contribution, we describe the technical solutions adopted for the new disk and tape endpoints at the sites, and we report on the commissioning and scale testing of the service. We detail the procedures implemented by CMS computing operations to actively manage data on disk at Tier-1 sites, and we give examples of the benefits brought to CMS workflows by the additional flexibility of the new system.« less

Pooling the resources of the CMS Tier-1 sites

NASA Astrophysics Data System (ADS)

Apyan, A.; Badillo, J.; Diaz Cruz, J.; Gadrat, S.; Gutsche, O.; Holzman, B.; Lahiff, A.; Magini, N.; Mason, D.; Perez, A.; Stober, F.; Taneja, S.; Taze, M.; Wissing, C.

2015-12-01

The CMS experiment at the LHC relies on 7 Tier-1 centres of the WLCG to perform the majority of its bulk processing activity, and to archive its data. During the first run of the LHC, these two functions were tightly coupled as each Tier-1 was constrained to process only the data archived on its hierarchical storage. This lack of flexibility in the assignment of processing workflows occasionally resulted in uneven resource utilisation and in an increased latency in the delivery of the results to the physics community. The long shutdown of the LHC in 2013-2014 was an opportunity to revisit this mode of operations, disentangling the processing and archive functionalities of the Tier-1 centres. The storage services at the Tier-1s were redeployed breaking the traditional hierarchical model: each site now provides a large disk storage to host input and output data for processing, and an independent tape storage used exclusively for archiving. Movement of data between the tape and disk endpoints is not automated, but triggered externally through the WLCG transfer management systems. With this new setup, CMS operations actively controls at any time which data is available on disk for processing and which data should be sent to archive. Thanks to the high-bandwidth connectivity guaranteed by the LHCOPN, input data can be freely transferred between disk endpoints as needed to take advantage of free CPU, turning the Tier-1s into a large pool of shared resources. The output data can be validated before archiving them permanently, and temporary data formats can be produced without wasting valuable tape resources. Finally, the data hosted on disk at Tier-1s can now be made available also for user analysis since there is no risk any longer of triggering chaotic staging from tape. In this contribution, we describe the technical solutions adopted for the new disk and tape endpoints at the sites, and we report on the commissioning and scale testing of the service. We detail the procedures implemented by CMS computing operations to actively manage data on disk at Tier-1 sites, and we give examples of the benefits brought to CMS workflows by the additional flexibility of the new system.

Technique for recovery of voice data from heat damaged magnetic tape

NASA Technical Reports Server (NTRS)

Melugin, J. F.; Obrien, D. E., III (Inventor)

1974-01-01

A method for conditioning, and thus enabling retrieval of intelligence from, magnetic tapes after damage from heat has caused the tape to wrinkle and curl severely thereby reducing tape width to less than one-half its original size. The damaged tape is superposed on a first piece of splicing tape with the oxide side of the magnetic tape in contact with the adhesive side of the splicing tape and then carefully smoothed by a special tool. A second piece of splicing tape is placed on the backing side of the magnetic tape then the resulting tape stack is trimmed to the original width of the magnetic tape. After the first piece of splicing tape is carefully removed from the oxide side of the damaged magnetic tape, the resulting magnetic tape is then ready to be placed into a recorder for playback.

From the CMS Computing Experience in the WLCG STEP'09 Challenge to the First Data Taking of the LHC Era

NASA Astrophysics Data System (ADS)

Bonacorsi, D.; Gutsche, O.

The Worldwide LHC Computing Grid (WLCG) project decided in March 2009 to perform scale tests of parts of its overall Grid infrastructure before the start of the LHC data taking. The "Scale Test for the Experiment Program" (STEP'09) was performed mainly in June 2009 -with more selected tests in September- October 2009 -and emphasized the simultaneous test of the computing systems of all 4 LHC experiments. CMS tested its Tier-0 tape writing and processing capabilities. The Tier-1 tape systems were stress tested using the complete range of Tier-1 work-flows: transfer from Tier-0 and custody of data on tape, processing and subsequent archival, redistribution of datasets amongst all Tier-1 sites as well as burst transfers of datasets to Tier-2 sites. The Tier-2 analysis capacity was tested using bulk analysis job submissions to backfill normal user activity. In this talk, we will report on the different performed tests and present their post-mortem analysis.

Ohio's statewide land use inventory: An operational approach for applying LANDSAT data to state, regional and local planning programs

NASA Technical Reports Server (NTRS)

Baldridge, P. E.; Geosling, P. H.; Leone, F.; Minshall, C.; Rodgers, R. H.; Wilhelm, C. L.

1975-01-01

The programmatic, technical, user application, and cost factors associated with the development of an operational, statewide land use inventory from LANDSAT data are described. The LANDSAT multispectral data are subjected to geometrical and categorical processing to produce map files for each of the 200 fifteen (15) minute quads covering Ohio. Computer compatible tapes are rescanned to produce inventory tapes which identify eight (8) Level I land use categories and a variety of Level II categories. The inventory tapes are processed through a series of ten (10) software programs developed by the State of Ohio. The net result is a computerized inventory which can be displayed in map or tabular form for various geographic units, at a variety of scales and for selected categories of usage. The computerized inventory data files are applied to technical programs developed by the various state agencies to be used in state, regional, and local planning programs.

Niobium-germanium superconducting tapes for high-field magnet applications

NASA Technical Reports Server (NTRS)

Braginski, A. I.; Roland, G. W.; Daniel, M. R.; Woolam, J. A.

1977-01-01

A process of fabricating superconducting Nb3Ge tapes by chemical vapor deposition (CVD) has been developed and tapes up to 10 meters long fabricated. The typical properties achieved were: critical temperature T sub c = 20 K, upper critical field H sub c2 = 29 tesla at 4.2 K, and J sub c = 3 to 4 x 10 to the 8th power A m(-2) at 4.2 K, 18 tesla. The relative depression of T sub c and H sub c2 compared with the best thin film samples sputtered on sapphire was due to the presence of Nb5Ge3 second-phase particles used as flux pinning centers and to strains induced by thermal mixmatch with Hastelloy B tape substrates. A peculiar field dependence of flux pinning force that was observed in both CVD and sputtered Nb3Ge indicated a premature pin-breaking mechanism or a phase inhomogeneity. Directions of further optimization work were defined.

Volume server: A scalable high speed and high capacity magnetic tape archive architecture with concurrent multi-host access

NASA Technical Reports Server (NTRS)

Rybczynski, Fred

1993-01-01

A major challenge facing data processing centers today is data management. This includes the storage of large volumes of data and access to it. Current media storage for large data volumes is typically off line and frequently off site in warehouses. Access to data archived in this fashion can be subject to long delays, errors in media selection and retrieval, and even loss of data through misplacement or damage to the media. Similarly, designers responsible for architecting systems capable of continuous high-speed recording of large volumes of digital data are faced with the challenge of identifying technologies and configurations that meet their requirements. Past approaches have tended to evaluate the combination of the fastest tape recorders with the highest capacity tape media and then to compromise technology selection as a consequence of cost. This paper discusses an architecture that addresses both of these challenges and proposes a cost effective solution based on robots, high speed helical scan tape drives, and large-capacity media.

Zn-site Substitution Effect in YbCo2Zn20

NASA Astrophysics Data System (ADS)

Kobayashi, Riki; Takamura, Haruki; Higa, Yasuyuki; Ikeda, Yoichi; Matsubayashi, Kazuyuki; Uwatoko, Yoshiya; Yoshizawa, Hideki; Aso, Naofumi

2017-04-01

We have investigated the substitution effect of YbCo2(Zn1-xTx)20 (T = Cu, Ga, and Cd) systems by using the experiments of X-ray powder diffraction (XRPD), specific heat, magnetic susceptibility, magnetization, and electrical resistivity in order to find out a material that approaches a quantum critical point by chemical pressure. The XRPD and electrical resistivity measurements clarify that the Cu-substitution makes the lattice constants shrink and keeps the magnetic electrical resistivity high, while the Ga- and the Cd-substitution show opposite relation of the Cu-substitution. However, we could not detect clear substitution effect in the specific heat, magnetic susceptibility, and magnetization measurements of Cu-substitution system within our experiments. It is necessary that to study the Cu-substitution samples that have higher x value at lower temperature.

Magnetic levitation and its application for education devices based on YBCO bulk superconductors

NASA Astrophysics Data System (ADS)

Yang, W. M.; Chao, X. X.; Guo, F. X.; Li, J. W.; Chen, S. L.

2013-10-01

A small superconducting maglev propeller system, a small spacecraft model suspending and moving around a terrestrial globe, several small maglev vehicle models and a magnetic circuit converter have been designed and constructed. The track was paved by NdFeB magnets, the arrangement of the magnets made us easy to get a uniform distribution of magnetic field along the length direction of the track and a high magnetic field gradient in the lateral direction. When the YBCO bulks mounted inside the vehicle models or spacecraft model was field cooled to LN2 temperature at a certain distance away from the track, they could be automatically floating over and moving along the track without any obvious friction. The models can be used as experimental or demonstration devices for the magnetic levitation applications.

Platinum group metals as flux pinning additions in screen printed superconducting YBa 2Cu 3O 7-δ thick films

NASA Astrophysics Data System (ADS)

Langhorn, J.; Bi, Y. J.; Abell, J. S.

1996-02-01

Platinum group metal additions made to thick films of YBCO have induced significant improvements in the superconducting properties, in particular critical current densities ( Jc). Values in excess of 7 × 10 3 A cm -2 at 77 K and zero applied field have been measured. Optical and transmission electron microscopy have shown a homogeneous distribution of sub-micron sized, and larger highly anisotropic 211, believed to result from a reaction between Pt and YBCO to create nucleation sites for 211 precipitates. Indirect supporting thermal analysis evidence for this reaction is presented. An increased density of dislocations associated with the {123}/{211} interface suggests that refined 211 precipitates may act as heterogeneous nucleation sites for flux pinning defects. Similar effects have been observed for additions of other platinum group metals (Rh, Pd).

The Dirac Experiments - Results and Challenges

NASA Astrophysics Data System (ADS)

Clark, R. G.; O'Brien, J. L.; Dzurak, A. S.; Kane, B. E.; Lumpkin, N. E.; Reilley, D. J.; Starrett, R. P.; Rickel, D. G.; Goettee, J. D.; Campbell, L. J.; Fowler, C. M.; Mielke, C.; Harrison, N.; Zerwekh, W. D.; Clark, D.; Bartram, B. D.; King, J. C.; Parkin, D.; Nakagawa, H.; Miura, N.

2004-11-01

The 1997 international Dirac II Series held at Los Alamos National Laboratory involved low temperature electrical transport and optical experiments in magnetic fields exceeding 800 T, produced by explosive flux compression using Russian MC-1 generators. An overview of the scientific and technical advances achieved in this Series is given, together with a strategy for future work in this challenging experimental environment. A significant outcome was achieved in transport studies of microfabricated thin-film YBCO structures with the magnetic field in the CuO plane. Using a GHz transmission line technique at an ambient temperature of 1.6 K, an onset of dissipation was observed at 150 T (a new upper bound for superconductivity in any material), with a saturation of resistivity at 240 T. Comparison with the Pauli limit expected at B - 155 T in this material suggests that the critical field in this geometry is limited by spin paramagnetism. In preparation for a Dirac III series, a systematic temperature-dependent transport study of YBCO using in-plane magnetic fields of 150 T generated by single-turn coils, at temperatures over the range 10-100 K, has been undertaken in collaboration with the Japanese Megagauss Laboratory. The objective is to map out the phase diagram for this geometry, which is expected to be significantly different than the Werthamer-Helfand-Hohenberg model due to the presence of paramagnetic limiting. Nanofabricated magnetometers have also been developed in a UNSW-LANL collaboration for use in Dirac III for Fermi surface measurements of YBCO in megagauss fields, which are described.

Effect of texture dispersion on the effective biaxial modulus of fiber-textured hexagonal, tetragonal, and orthorhombic films

NASA Astrophysics Data System (ADS)

Wu, Huaping; Wu, Linzhi; Du, Shanyi

2008-04-01

The effective biaxial modulus (Meff) of fiber-textured hexagonal, tetragonal, and orthorhombic films is estimated by using the Voigt-Reuss-Hill and Vook-Witt grain-interaction models. The orientation distribution function with Gaussian distributions of the two Euler angles θ and ϕ is adopted to analyze the effect of texture dispersion degree on Meff. Numerical results that are based on ZnO, BaTiO3, and yttrium barium copper oxide (YBCO) materials show that the Vook-Witt average of Meff is identical to the Voigt-Reuss-Hill average of Meff for the (001) plane of ideally fiber-textured hexagonal and tetragonal films. The ϕ distribution has no influence on Meff of the (hkl)-fiber-textured hexagonal film at any θ distribution in terms of the isotropy in the plane perpendicular to the [001] direction. Comparably, tetragonal and orthorhombic films represent considerable actions of ϕ dispersion on Meff, and the effect of ϕ dispersion on Meff of a (001)-fiber-textured YBCO film is smaller than that for a (001)-fiber-textured BaTiO3 film since the shear anisotropic factor in the (001) shear plane of a YBCO film more closely approaches 1. Enhanced θ and ϕ distributions destroy the perfect fiber textures, and as a result, the films exhibit an evolution from ideal (hkl) fiber textures to random textures with varying full widths at half maximums of θ and ϕ.

Stability mechanical considerations, and AC loss in HTSC monoliths, coils, and wires

NASA Technical Reports Server (NTRS)

Sumption, M. D.; Collings, E. W.

1995-01-01

For monolithic high-T(sub c) superconductors (HTSC's) calculations are presented of: (1) the initial flux jump field, H(sub fj), in melt-processed YBCO based on a field and temperature dependent J(sub c), and (2) the radial and circumferential stresses in solid and hollow cylinders containing trapped magnetic flux. For model multi filamentary (MF) HTSC/Ag strands calculations are presented of: (1) the limiting filament diameters for adiabatic and dynamic stability, and (2) the hysteretic and eddy current components of AC loss. Again for MF HTSC/Ag composite strands the need for filamentary subdivision and twisting is discussed.

Precision and accuracy of manual water-level measurements taken in the Yucca Mountain area, Nye County, Nevada, 1988-90

USGS Publications Warehouse

Boucher, M.S.

1994-01-01

Water-level measurements have been made in deep boreholes in the Yucca Mountain area, Nye County, Nevada, since 1983 in support of the U.S. Department of Energy's Yucca Mountain Project, which is an evaluation of the area to determine its suitability as a potential storage area for high-level nuclear waste. Water-level measurements were taken either manually, using various water-level measuring equipment such as steel tapes, or they were taken continuously, using automated data recorders and pressure transducers. This report presents precision range and accuracy data established for manual water-level measurements taken in the Yucca Mountain area, 1988-90. Precision and accuracy ranges were determined for all phases of the water-level measuring process, and overall accuracy ranges are presented. Precision ranges were determined for three steel tapes using a total of 462 data points. Mean precision ranges of these three tapes ranged from 0.014 foot to 0.026 foot. A mean precision range of 0.093 foot was calculated for the multiconductor cable, using 72 data points. Mean accuracy values were calculated on the basis of calibrations of the steel tapes and the multiconductor cable against a reference steel tape. The mean accuracy values of the steel tapes ranged from 0.053 foot, based on three data points to 0.078, foot based on six data points. The mean accuracy of the multiconductor cable was O. 15 foot, based on six data points. Overall accuracy of the water-level measurements was calculated by taking the square root of the sum of the squares of the individual accuracy values. Overall accuracy was calculated to be 0.36 foot for water-level measurements taken with steel tapes, without accounting for the inaccuracy of borehole deviations from vertical. An overall accuracy of 0.36 foot for measurements made with steel tapes is considered satisfactory for this project.

Systematic Review of the Effect of Taping Techniques on Patellofemoral Pain Syndrome.

PubMed

Logan, Catherine A; Bhashyam, Abhiram R; Tisosky, Ashley J; Haber, Daniel B; Jorgensen, Anna; Roy, Adam; Provencher, Matthew T

Taping is commonly used in the management of several musculoskeletal conditions, including patellofemoral pain syndrome (PFPS). Specific guidelines for taping are unknown. To investigate the efficacy of knee taping in the management of PFPS. Our hypothesis was that tension taping and exercise would be superior to placebo taping and exercise as well as to exercise or taping alone. The PubMed/MEDLINE, Cochrane, Rehabilitation and Sports Medicine Source, and CINAHL databases were reviewed for English-language randomized controlled trials (RCTs) evaluating the efficacy of various taping techniques that were published between 1995 and April 2015. Keywords utilized included taping, McConnell, kinesio-taping, kinesiotaping, patellofemoral pain, and knee. Studies included consisted of RCTs (level 1 or 2) with participants of all ages who had anterior knee or patellofemoral pain symptoms and had received nonsurgical management using any taping technique. Systematic review. Level 2. A checklist method was used to determine selection, performance, detection, and attrition bias for each article. A quality of evidence grading was then referenced using the validated PEDro database for RCTs. Three difference comparison groups were compared: tension taping and exercise versus placebo taping and exercise (group 1), placebo taping and exercise versus exercise alone (group 2), and tension taping and exercise versus taping alone (group 3). Five RCTs with 235 total patients with multiple intervention arms were included. Taping strategies included McConnell and Kinesiotaping. Visual analog scale (VAS) scores indicated improvement in all 3 comparison groups (group 1: 91 patients, 39% of total, mean VAS improvement 44.9 [tension taping + exercise] vs 66 [placebo taping + exercise]; group 2: 56 patients, 24% of total, mean VAS improvement 66 [placebo taping + exercise] vs 47.6 [exercise alone]; and group 3: 112 patients, 48% of total, mean VAS improvement 44.9 [tension taping + exercise] vs 14.1 [taping alone]). This systematic review supports knee taping only as an adjunct to traditional exercise therapy for PFPS; however, it does not support taping in isolation.

Continuous welding of unidirectional fiber reinforced thermoplastic tape material

NASA Astrophysics Data System (ADS)

Schledjewski, Ralf

2017-10-01

Continuous welding techniques like thermoplastic tape placement with in situ consolidation offer several advantages over traditional manufacturing processes like autoclave consolidation, thermoforming, etc. However, still there is a need to solve several important processing issues before it becomes a viable economic process. Intensive process analysis and optimization has been carried out in the past through experimental investigation, model definition and simulation development. Today process simulation is capable to predict resulting consolidation quality. Effects of material imperfections or process parameter variations are well known. But using this knowledge to control the process based on online process monitoring and according adaption of the process parameters is still challenging. Solving inverse problems and using methods for automated code generation allowing fast implementation of algorithms on targets are required. The paper explains the placement technique in general. Process-material-property-relationships and typical material imperfections are described. Furthermore, online monitoring techniques and how to use them for a model based process control system are presented.

The reduction of optimal heat treatment temperature and critical current density enhancement of ex situ processed MgB2 tapes using ball milled filling powder

NASA Astrophysics Data System (ADS)

Fujii, Hiroki; Iwanade, Akio; Kawada, Satoshi; Kitaguchi, Hitoshi

2018-01-01

The optimal heat treatment temperature (Topt) at which best performance in the critical current density (Jc) property at 4.2 K is obtained is influenced by the quality or reactivity of the filling powder in ex situ processed MgB2 tapes. Using a controlled fabrication process, the Topt decreases to 705-735 °C, which is lower than previously reported by more than 50 °C. The Topt decrease is effective to suppress both the decomposition of MgB2 and hence the formation of impurities such as MgB4, and the growth of crystallite size which decreases upper critical filed (Hc2). These bring about the Jc improvement and the Jc value at 4.2 K and 10 T reaches 250 A/mm2. The milling process also decreases the critical temperature (Tc) below 30 K. The milled powder is easily contaminated in air and thus, the Jc property of the contaminated tapes degrades severely. The contamination can raise the Topt by more than 50 °C, which is probably due to the increased sintering temperature required against contaminated surface layer around the grains acting as a barrier.

Automated Tape Laying Machine for Composite Structures.

DTIC Science & Technology

The invention comprises an automated tape laying machine, for laying tape on a composite structure. The tape laying machine has a tape laying head...neatly cut. The automated tape laying device utilizes narrow width tape to increase machine flexibility and reduce wastage.

Origin of intrinsic Josephson coupling in the cuprates and its relation to order parameter symmetry: An incoherent hopping model

NASA Astrophysics Data System (ADS)

Radtke, R. J.; Levin, K.

1995-02-01

Experiments on the cuprate superconductors demonstrate that these materials may be viewed as a stack of Josephson junctions along the direction normal to the CuO 2 planes (the c-axis). In this paper, we present a model which describes this intrinsic Josephson coupling in terms of incherent quasiparticle hopping along the c-axis arising from wave-function overlap, impurity-assisted hopping, and boson-assised hopping. We use this model to compute the magnitude and temperature T dependence of the resulting Josephson critical current jc( T) for s- and d-wave superconductors. Contrary to other approaches, d-wave pairing in this model is compatible with an intrinsic Josephson effect at all hole concentrations and leads to jc( T) αT at low T. By parameterizing our theory with c-axis resistivity data from YBa 2Cu 3O 7-δ (YBCO), we estimate jc( T) for optimally doped and underdoped members of this family. jc( T) can be measured either directly or indirectly through microwave penetration depth experiments, and current measurements on Bi 2Sr 2CaCu 2O 8 and La 2- xSr xCuO 4 are found to be consistent with s-wave pairing and the dominance of assisted hopping processes. The situation in YBCO is still unclear, but our estimates suggest that further experiments on this compound would be of great help in elucidating the validity of our model in general and the pairing symmetry in particular.

Superconductor-Mediated Modification of Gravity? AC Motor Experiments with Bulk YBCO Disks in Rotating Magnetic Fields

NASA Technical Reports Server (NTRS)

Noever, David A.; Koczor, Ronald J.; Roberson, Rick

1998-01-01

We have previously reported results using a high precision gravimeter to probe local gravity changes in the neighborhood of large bulk-processed high-temperature superconductors. Podkietnov, et al (Podkietnov, E. and Nieminen, R. (1992) A Possibility of Gravitational Force Shielding by Bulk YBa2 Cu3 O7-x Superconductor, Physica C, C203:441-444.) have indicated that rotating AC fields play an essential role in their observed distortion of combined gravity and barometric pressure readings. We report experiments on large (15 cm diameter) bulk YBCO ceramic superconductors placed in the core of a three-phase, AC motor stator. The applied rotating field produces up to a 12,000 revolutions per minute magnetic field. The field intensity decays rapidly from the maximum at the outer diameter of the superconducting disk (less than 60 Gauss) to the center (less than 10 Gauss). This configuration was applied with and without a permanent DC magnetic field levitating the superconducting disk, with corresponding gravity readings indicating an apparent increase in observed gravity of less than 1 x 10(exp -6)/sq cm, measured above the superconductor. No effect of the rotating magnetic field or thermal environment on the gravimeter readings or on rotating the superconducting disk was noted within the high precision of the observation. Implications for propulsion initiatives and power storage flywheel technologies for high temperature superconductors will be discussed for various spacecraft and satellite applications.

Aspects of forming metal-clad melt-processed Y-Ba-Cu-O tapes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kozlowski, G.; Oberly, C.E.; Ho, J.

1991-03-01

This paper reports on melt-processing of Y-Ba-Cu-O superconductor in a usable form for magnet winding which requires the development of a cladding with demanding properties. Numerous recent efforts in cold forming Bi-based superconductor tapes have been successful because a silver tube can be used to constrain the ceramic material, which is sintered at much lower temperature than the Y-Ba-Cu-O. Typical high temperature metals which can be used to encase Y-Ba-Cu-O during sintering do not permit ready diffusion of oxygen as silver does. Recently, the full or partial recovery of superconductivity has been achieved in transition-metal- doped Y-Ba-Cu-O due to themore » partial-melt processing.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

John J. Gangloff Jr; Shatil Sinha; Suresh G. Advani

The formation and transport of voids in composite materials remains a key research area in composite manufacturing science. Knowledge of how voids, resin, and fiber reinforcement propagate throughout a composite material continuum from green state to cured state during an automated tape layup process is key to minimizing defects induced by void-initiated stress concentrations under applied loads for a wide variety of composite applications. This paper focuses on modeling resin flow in a deforming fiber tow during an automated process of partially impregnated thermoset prepreg composite material tapes. In this work, a tow unit cell based model has been presentedmore » that determines the consolidation and impregnation of a thermoset prepreg tape under an input pressure profile. A parametric study has been performed to characterize the behavior of varying tow speed and compaction forces on the degree of consolidation. Results indicate that increased tow consolidation is achieved with slower tow speeds and higher compaction forces although the relationship is not linear. The overall modeling of this project is motivated to address optimization of the 'green state' composite properties and processing parameters to reduce or eliminate 'cured state' defects, such as porosity and de-lamination. This work is partially funded by the Department of Energy under Award number DE-EE0001367.« less

Organic materials for ceramic molding processes

NASA Technical Reports Server (NTRS)

Saito, K.

1984-01-01

Ceramic molding processes are examined. Binders, wetting agents, lubricants, plasticizers, surface active agents, dispersants, etc., for pressing, rubber pressing, sip casting, injection casting, taping, extrusion, etc., are described, together with forming machines.

Improving the Spacelab mass memory unit tape layout with a simulation model

NASA Technical Reports Server (NTRS)

Noneman, S. R.

1984-01-01

A tape drive called the Mass Memory Unit (MMU) stores software used by Spacelab computers. MMU tape motion must be minimized during typical flight operations to avoid a loss of scientific data. A projection of the tape motion is needed for evaluation of candidate tape layouts. A computer simulation of the scheduled and unscheduled MMU tape accesses is developed for this purpose. This simulation permits evaluations of candidate tape layouts by tracking and summarizing tape movements. The factors that affect tape travel are investigated and a heuristic is developed to find a good tape layout. An improved tape layout for Spacelab I is selected after the evaluation of fourteen candidates. The simulation model will provide the ability to determine MMU layouts that substantially decrease the tape travel on future Spacelab flights.

Enhanced critical currents in (Gd,Y)Ba2Cu3Ox superconducting tapes with high levels of Zr addition

NASA Astrophysics Data System (ADS)

Selvamanickam, V.; Chen, Y.; Shi, T.; Liu, Y.; Khatri, N. D.; Liu, J.; Yao, Y.; Xiong, X.; Lei, C.; Soloveichik, S.; Galstyan, E.; Majkic, G.

2013-03-01

The critical current and structural properties of (Gd,Y)BaCuO tapes made by metal organic chemical vapor deposition (MOCVD) with Zr addition levels up to 30 at.% have been investigated. The reduction in critical current beyond the previously optimized Zr addition level of 7.5 at.% was found to be due to structural deterioration of the (Gd,Y)Ba2Cu3Ox film. By a modified MOCVD process, enhanced critical current densities have been achieved with high levels of Zr addition, including 3.83 MA cm-2 in 15 at.% Zr-added 1.1 μm thick film at 77 K in zero magnetic field. Critical currents as high as 1072 A/12 mm have been reached in (Gd,Y)BaCuO tapes with 15 at.% Zr addition at 30 K in a field of 3 T applied perpendicular to the tape, corresponding to a pinning force value of 268 GN m-3. The enhanced critical currents achievable with a high density of nanoscale defects by employing high levels of second-phase additions enable the performance targets needed for the use of HTS tapes in coil applications involving high magnetic fields at temperatures below 50 K to be met.

Two chamber reaction furnace

DOEpatents

Blaugher, Richard D.

1998-05-05

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Vertical two chamber reaction furnace

DOEpatents

Blaugher, Richard D.

1999-03-16

A vertical two chamber reaction furnace. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700.degree. and 800.degree. C.) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800.degree. to 950.degree. C. to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product.

Two chamber reaction furnace

DOEpatents

Blaugher, R.D.

1998-05-05

A vertical two chamber reaction furnace is described. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium-copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 C and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

Vertical two chamber reaction furnace

DOEpatents

Blaugher, R.D.

1999-03-16

A vertical two chamber reaction furnace is disclosed. The furnace comprises a lower chamber having an independently operable first heating means for heating the lower chamber and a gas inlet means for admitting a gas to create an ambient atmosphere, and an upper chamber disposed above the lower chamber and having an independently operable second heating means for heating the upper chamber. Disposed between the lower chamber and the upper chamber is a vapor permeable diffusion partition. The upper chamber has a conveyor means for conveying a reactant there through. Of particular importance is the thallinating of long-length thallium-barium-calcium copper oxide (TBCCO) or barium-calcium-copper oxide (BCCO) precursor tapes or wires conveyed through the upper chamber to thereby effectuate the deposition of vaporized thallium (being so vaporized as the first reactant in the lower chamber at a temperature between about 700 and 800 C) on TBCCO or BCCO tape or wire (the second reactant) at its simultaneous annealing temperature in the upper chamber of about 800 to 950 C to thereby replace thallium oxide lost from TBCCO tape or wire because of the high annealing temperature or to deposit thallium on BCCO tape or wire. Continuously moving the tape or wire provides a single-step process that effectuates production of long-length TBCCO superconducting product. 2 figs.

Status of the Landsat thematic mapper and multispectral scanner archive conversion system

USGS Publications Warehouse

Werner, Darla J.

1993-01-01

The U.S. Geological Survey's EROS Data Center (EDC) manages the National Satellite Land Remote Sensing Data Archive. This archive includes Landsat thematic mapper (TM) multispectral scanner (MSS) data acquired since 1972. The Landsat archive is an important resource to global change research. To ensure long-term availability of Landsat data from the archive, the EDC specified requirements for a Thematic Mapper and Multispectral Scanner Archive Conversion System (TMACS) that would preserve the data by transcribing it to a more durable medium. In addition to media conversion, hardware and software was installed at EDC in July 1992. In December 1992, the EDC began converting Landsat MSS data from high-density, open reel instrumentation tapes to digital cassette tapes. Almost 320,000 MSS images acquired since 1979 and more than 200,000 TM images acquired since 1982 will be converted to the new medium during the next 3 years. During the media conversion process, several high-density tapes have exhibited severe binder degradation. Even though these tapes have been stored in environmentally controlled conditions, hydrolysis has occurred, resulting in "sticky oxide shed". Using a thermostatically controlled oven built at EDC, tape "baking" has been 100 percent successful and actually improves the quality of some images.

TiO2/water Nanofluid Heat Transfer in Heat Exchanger Equipped with Double Twisted-Tape Inserts

NASA Astrophysics Data System (ADS)

Eiamsa-ard, S.; Ketrain, R.; Chuwattanakul, V.

2018-05-01

Nowadays, heat transfer enhancement plays an important role in improving efficiency of heat transfer and thermal systems for numerous areas such as heat recovery processes, chemical reactors, air-conditioning/refrigeration system, food engineering, solar air/water heater, cooling of high power electronics etc. The present work presents the experimental results of the heat transfer enhancement of TiO2/water nanofluid in a heat exchanger tube fitted with double twisted tapes. The study covered twist ratios of twisted tapes (y/w) of 1.5, 2.0, and 2.5) while the concentration of the nanofluid was kept constant at 0.05% by volume. Observations show that heat transfer, friction loss and thermal performance increase as twist ratio (y/w) decreases. The use of the nanofluid in the tube equipped with the double twisted-tapes with the smallest twist ratio (y/w = 1.5) results in the increases of heat transfer rates and friction factor up to 224.8% and 8.98 times, respectively as compared to those of water. In addition, the experimental results performed that double twisted tapes induced dual swirling-flows which played an important role in improving fluid mixing and heat transfer enhancement. It is also observed that the TiO2/water nanofluid was responsible for low pressure loss behaviors.

Towards a molecular logic machine

NASA Astrophysics Data System (ADS)

Remacle, F.; Levine, R. D.

2001-06-01

Finite state logic machines can be realized by pump-probe spectroscopic experiments on an isolated molecule. The most elaborate setup, a Turing machine, can be programmed to carry out a specific computation. We argue that a molecule can be similarly programmed, and provide examples using two photon spectroscopies. The states of the molecule serve as the possible states of the head of the Turing machine and the physics of the problem determines the possible instructions of the program. The tape is written in an alphabet that allows the listing of the different pump and probe signals that are applied in a given experiment. Different experiments using the same set of molecular levels correspond to different tapes that can be read and processed by the same head and program. The analogy to a Turing machine is not a mechanical one and is not completely molecular because the tape is not part of the molecular machine. We therefore also discuss molecular finite state machines, such as sequential devices, for which the tape is not part of the machine. Nonmolecular tapes allow for quite long input sequences with a rich alphabet (at the level of 7 bits) and laser pulse shaping experiments provide concrete examples. Single molecule spectroscopies show that a single molecule can be repeatedly cycled through a logical operation.

Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

NASA Technical Reports Server (NTRS)

Fleig, Albert J.; Mcpeters, R. D.; Bhartia, P. K.; Schlesinger, Barry M.; Cebula, Richard P.; Klenk, K. F.; Taylor, Steven L.; Heath, Donald F.

1990-01-01

Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones.

EFFECT OF ATHLETIC TAPING AND KINESIOTAPING® ON MEASUREMENTS OF FUNCTIONAL PERFORMANCE IN BASKETBALL PLAYERS WITH CHRONIC INVERSION ANKLE SPRAINS

PubMed Central

Karatas, Nihan; Baltaci, Gul

2012-01-01

Background: Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. Purpose: To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Study Design: Crossover Study Design Methods: Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. Results: There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Conclusion: Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Clinical Relevance: Ankle taping using Kinesio Tex® Tape did not inhibit functional performance. PMID:22530190

Effect of athletic taping and kinesiotaping® on measurements of functional performance in basketball players with chronic inversion ankle sprains.

PubMed

Bicici, Seda; Karatas, Nihan; Baltaci, Gul

2012-04-01

Chronic inversion ankle sprains are common in basketball players. The effect of taping on functional performance is disputed in the literature. Kinesiotaping® (KT®) is a new method that is being used as both a therapeutic and performance enhancement tool. To date, it appears that no study has investigated the effect of ankle KT® on functional performance. To investigate the effects of different types of taping (KT® using Kinesio Tex®, athletic taping) on functional performance in athletes with chronic inversion sprains of the ankle. Crossover Study Design Fifteen male basketball players with chronic inversion ankle sprains between the ages of 18 and 22 participated in this study. Functional performance tests (Hopping test by Amanda et al, Single Limb Hurdle Test, Standing Heel Rise test, Vertical Jump Test, The Star Excursion Balance Test [SEBT] and Kinesthetic Ability Trainer [KAT] Test) were used to quantify agility, endurance, balance, and coordination. These tests were conducted four times at one week intervals using varied conditions: placebo tape, without tape, standard athletic tape, and KT®. One-way ANOVA tests were used to examine difference in measurements between conditions. Bonferroni correction was applied to correct for repeated testing. There were no significant differences among the results obtained using the four conditions for SEBT (anterior p=0.0699; anteromedial p=0.126; medial p=0.550; posteromedial p=0.587; posterior p=0.754; posterolateral p=0.907; lateral p=0.124; anterolateral p=0.963) and the KAT dynamic measurement (p=0.388). Faster performance times were measured with KT® and athletic tape in single limb hurdle test when compared to placebo and non-taped conditions (Athletic taping- placebo taping: p=0.03; athletic taping- non tape p=0.016;KT®- Placebo taping p=0.042; KT®-Non tape p=0.016). In standing heel rise test and vertical jump test, athletic taping led to decreased performance. (Standing heel rise test: Athletic taping- placebo taping p=0.035; athletic taping- non tape p=0.043; athletic tape- KT® p<0.001) (Vertical jump test: Athletic taping- placebo taping p=0.002: athletic taping- non tape p=0.002; KT®- athletic tape p<0.001) Kinesiotaping® had no negative effects on a battery of functional performance tests and improvements were seen in some functional performance tests. Ankle taping using Kinesio Tex® Tape did not inhibit functional performance.

A Combinatorial Geometry Computer Description of the XR311 Vehicle

DTIC Science & Technology

1978-04-01

cards or magnetic tape. The shot line output of the GRID subroutine of the GIFT code is also stored on magnetic tape for future vulnera- bility...descriptions as processed by the Geometric Information For Targets ( GIFT )2 computer code. This report documents the COM-GEOM target description for all...72, March 1974. ’L.W. Bains and M.J. Reisinger, "The GIFT Code User Manual, VOL 1, Introduction and Input Requirements, " Ballistic Research

Progress in development of tapes and magnets made from Bi-2223 superconductors

NASA Technical Reports Server (NTRS)

Balachandran, U.; Iyer, A. N.; Haldar, P.; Hoehn, J. G., Jr.; Motowidlo, L. R.

1995-01-01

Long lengths of (Bi,Pb)2Sr2Ca2Cu3O(x) tapes made by powder-in-tube processing have been wound into coils. Performance of the coils has been measured at temperatures of 4.2 to 77 K, and microstructures have been examined by x-ray diffraction and electron microscopy and then related to superconducting properties. A summary of recent results and an overview of future goals are presented.

ARC-1966-A-37949-4

NASA Image and Video Library

1966-11-29

MR. J. WARFEL, D. TRACEY, T. BROWNE, D. KLAUK, MRS L. McCORMICK, C. BATINOVICH, WORKING IN THE DATA ANALYSIS MANAGEMENT AREA OF THE PIONEER TAPE PROCESSING STATION. Pioneer Off-Line Data Processing System.

Evaluation of a new silicone adhesive tape among clinicians caring for patients with fragile or at-risk skin.

PubMed

Manriquez, Sonia; Loperfido, Bonnie; Smith, Graham

2014-04-01

To evaluate performance of a new silicone tape among clinicians caring for patients with fragile skin. An international, multisite, 2-week-use evaluation. Caregivers (n = 217) from acute care hospitals in the United States, United Kingdom, and France who regularly use tapes on patients with fragile skin. The silicone tape was substituted for current-use gentle tapes for a 2-week trial period. Preuse and postuse questionnaires were collected. The main outcome measure was tape preference. Secondary outcomes included (1) satisfaction with current-use tapes, (2) willingness to replace current-use tapes with silicone tape, (3) performance comparisons between tapes, (4) clinician-reported problems with the silicone tape, and (5) case study information. The sample group consisted of nurses (98.1%), assistants (1.4%), and physicians (0.5%). Hospital units (n = 100) included oncology (31%), medical-surgical (14%), dialysis (12%), infusion/intravenous therapy (16%), critical care (10%), wound care (10%), and other units (7%). Overall preference was 92.0% for the silicone tape, 7.5% for current-use tapes, and 0.5% no preference. Dissatisfaction was 61.2% for current-use tapes, and most clinicians (90.2%) would change to the silicone tape. Evaluators favored (≥71.5%) the silicone tape on 10 performance attributes and on overall performance (91.6%). Most evaluators (75.1%) did not experience problems with the silicone tape, and those who did found problems related to adhesion (77.8%), gentleness (16.0%), and residue (6.2%). These results indicate that the silicone tape fills a performance-expectation gap of current acrylic tapes among users of tapes on patients with fragile or at-risk skin.

Development of high T(sub c) (greater than 110 K) Bi, Tl, and Y-based materials as superconducting circuit elements

NASA Technical Reports Server (NTRS)

Haertling, Gene H.; Grabert, Gregory; Gilmour, Phillip

1992-01-01

Experimental work has continued on the development and characterization of bulk and hot pressed powders and tapecast materials in the Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems. A process for producing warp-free, sintered, superconducting tapes of Bi composition Bi2Sr2Ca2Cu3O(x) with a mixed oxide process was established. This procedure required a triple calcination at 830 C for 24 hours and sintering at 845 C from 20 to 200 hours. Hot pressing the triple calcined powder at 845 C for 6 hours at 5000 psi yielded a dense material which on further heat treatment at 845 C for 24 hours exhibited a Tc of 108.2 K. A further improvement in the processing of the bismuth materials was achieved via a chemical coprecipitation process wherein the starting nitrate materials were coprecipitated with oxalic acid, thus yielding a more chemically homogeneous, more reactive powder. With the coprecipitated powders, only one calcine at 830 C for 12 hours and a final sinter at 845 C for 30 hours was sufficient to produce a bulk superconducting material with a Tc of 108.4 K. SAFIRE-type grounding links were successfully fabricated from sintered, tapecast, coprecipitated BSCCO 2223 powders. Compositional and processing investigations were continued on the Tl-based superconductors. Manganese and lithium additions and sintering temperature and time were examined to determine their influence on superconducting properties. It was found that lithium substitutions for copper enhance the transition temperatures while manganese additions produced deleterious effects on the superconducting properties. A suitable procedure for producing reproducible bulk and tapecast material of Tl composition Tl2Ba2Ca2Cu3O(x) was developed and used in fabricating uniform superconducting tapes. The highest transition temperature for Tl-based tapes was measured at 110.2 K. Thallium superconducting SAFIRE-type grounding links were fabricated from the tapes.

Accuracy testing of steel and electric groundwater-level measuring tapes: Test method and in-service tape accuracy

USGS Publications Warehouse

Fulford, Janice M.; Clayton, Christopher S.

2015-10-09

The calibration device and proposed method were used to calibrate a sample of in-service USGS steel and electric groundwater tapes. The sample of in-service groundwater steel tapes were in relatively good condition. All steel tapes, except one, were accurate to ±0.01 ft per 100 ft over their entire length. One steel tape, which had obvious damage in the first hundred feet, was marginally outside the accuracy of ±0.01 ft per 100 ft by 0.001 ft. The sample of in-service groundwater-level electric tapes were in a range of conditions—from like new, with cosmetic damage, to nonfunctional. The in-service electric tapes did not meet the USGS accuracy recommendation of ±0.01 ft. In-service electric tapes, except for the nonfunctional tape, were accurate to about ±0.03 ft per 100 ft. A comparison of new with in-service electric tapes found that steel-core electric tapes maintained their length and accuracy better than electric tapes without a steel core. The in-service steel tapes could be used as is and achieve USGS accuracy recommendations for groundwater-level measurements. The in-service electric tapes require tape corrections to achieve USGS accuracy recommendations for groundwater-level measurement.

Operation and design selection of high temperature superconducting magnetic bearings

NASA Astrophysics Data System (ADS)

Werfel, F. N.; Floegel-Delor, U.; Riedel, T.; Rothfeld, R.; Wippich, D.; Goebel, B.

2004-10-01

Axial and radial high temperature superconducting (HTS) magnetic bearings are evaluated by their parameters. Journal bearings possess advantages over thrust bearings. High magnetic gradients in a multi-pole permanent magnet (PM) configuration, the surrounding melt textured YBCO stator and adequate designs are the key features for increasing the overall bearing stiffness. The gap distance between rotor and stator determines the specific forces and has a strong impact on the PM rotor design. We report on the designing, building and measuring of a 200 mm prototype 100 kg HTS bearing with an encapsulated and thermally insulated melt textured YBCO ring stator. The encapsulation requires a magnetically large-gap (4-5 mm) operation but reduces the cryogenic effort substantially. The bearing requires 3 l of LN2 for cooling down, and about 0.2 l LN2 h-1 under operation. This is a dramatic improvement of the efficiency and in the practical usage of HTS magnetic bearings.

High Temperature Superconducting Thick Films

DOEpatents

Arendt, Paul N.; Foltyn, Stephen R.; Groves, James R.; Holesinger, Terry G.; Jia, Quanxi

2005-08-23

An article including a substrate, a layer of an inert oxide material upon the surface of the substrate, (generally the inert oxide material layer has a smooth surface, i.e., a RMS roughness of less than about 2 nm), a layer of an amorphous oxide or oxynitride material upon the inert oxide material layer, a layer of an oriented cubic oxide material having a rock-salt-like structure upon the amorphous oxide material layer is provided together with additional layers such as at least one layer of a buffer material upon the oriented cubic oxide material layer or a HTS top-layer of YBCO directly upon the oriented cubic oxide material layer. With a HTS top-layer of YBCO upon at least one layer of a buffer material in such an article, Jc's of 1.4×106 A/cm2 have been demonstrated with projected Ic's of 210 Amperes across a sample 1 cm wide.

Growth and micro structural studies on Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) buffer layers

NASA Technical Reports Server (NTRS)

Srinivas, S.; Pinto, R.; Pai, S. P.; Dsousa, D. P.; Apte, P. R.; Kumar, D.; Purandare, S. C.; Bhatnagar, A. K.

1995-01-01

Microstructure of Yittria Stabilized Zirconia (YSZ) and Strontium Titanate (STO) of radio frequency magnetron sputtered buffer layers was studied at various sputtering conditions on Si (100), Sapphire and LaAlO3 (100) substrates. The effect of substrate temperatures up to 800 C and sputtering gas pressures in the range of 50 mTorr. of growth conditions was studied. The buffer layers of YSZ and STO showed a strong tendency for columnar growth was observed above 15 mTorr sputtering gas pressure and at high substrate temperatures. Post annealing of these films in oxygen atmosphere reduced the oxygen deficiency and strain generated during growth of the films. Strong c-axis oriented superconducting YBa2Cu3O7-x (YBCO) thin films were obtained on these buffer layers using pulsed laser ablation technique. YBCO films deposited on multilayers of YSZ and STO were shown to have better superconducting properties.

Quantitative magneto-optical analysis of the role of finite temperatures on the critical state in YBCO thin films

NASA Astrophysics Data System (ADS)

Albrecht, Joachim; Brück, Sebastian; Stahl, Claudia; Ruoß, Stephen

2016-11-01

We use quantitative magneto-optical microscopy to investigate the influence of finite temperatures on the critical state of thin YBCO films. In particular, temperature and time dependence of supercurrents in inhomogeneous and anisotropic films are analyzed to extract the role of temperature on the supercurrents themselves and the influence of thermally activated relaxation. We find that inhomogeneities and anisotropies of the current density distribution correspond to a different temperature dependence of local supercurrents. In addition, the thermally activated decay of supercurrents can be used to extract local vortex pinning energies. With these results the modification of vortex pinning introduced by substrate structures is studied. In summary the local investigation of supercurrent densities allows the full description of the vortex pinning landscape with respect to pinning forces and energies in superconducting films with complex properties under the influence of finite temperatures.

Hysteretic Vortex-Matching Effects in High-Tc Superconductors with Nanoscale Periodic Pinning Landscapes Fabricated by He Ion-Beam Projection

NASA Astrophysics Data System (ADS)

Zechner, G.; Jausner, F.; Haag, L. T.; Lang, W.; Dosmailov, M.; Bodea, M. A.; Pedarnig, J. D.

2017-07-01

Square arrays of submicrometer columnar defects in thin YBa2 Cu3 O7 -δ (YBCO) films with spacings down to 300 nm are fabricated by a He ion-beam projection technique. Pronounced peaks in the critical current and corresponding minima in the resistance demonstrate the commensurate arrangement of flux quanta with the artificial pinning landscape, despite the strong intrinsic pinning in epitaxial YBCO films. While these vortex-matching signatures are exactly at the predicted values in field-cooled experiments, they are displaced in zero-field-cooled, magnetic-field-ramped experiments, conserving the equidistance of the matching peaks and minima. These observations reveal an unconventional critical state in a cuprate superconductor with an artificial, periodic pinning array. The long-term stability of such out-of-equilibrium vortex arrangements paves the way for electronic applications employing fluxons.

Relationship of the Levitation Force Between Single and Multiple YBCO Bulks Above a Permanent Magnet Guideway Operating Dive-Lift Movement with Different Angles

NASA Astrophysics Data System (ADS)

Zeng, R.; Wang, S. Y.; Liao, X. L.; Deng, Z. G.; Wang, J. S.

2013-04-01

In practical applications, the acceleration and deceleration motions inevitably happen in the operation of high temperature superconducting (HTS) maglev trains. For further research of the maglev properties of YBaCuO bulk above a permanent magnet guideway (PMG), by moving a fixed vertical distance, this paper studies the relationship of the levitation force between single and multiple YBCO bulks above a PMG operating dive-lift movement with different angles. Experimental results show that the maximal levitation force increment of two bulks than one bulk is smaller than the maximal levitation force increment of three bulks than two bulks. With the degree decreasing, the maximal levitation force increment of three bulks is bigger than the maximal levitation force increment of two bulks and one bulk, and the hysteresis loop of the levitation force of the three-bulk arrangement is getting smaller.

Growth of epitaxial Pb(Zr,Ti)O3 films by pulsed laser deposition

NASA Astrophysics Data System (ADS)

Lee, J.; Safari, A.; Pfeffer, R. L.

1992-10-01

Lead zirconate titanate (PZT) thin films with a composition near the morphotropic phase boundary have been grown on MgO (100) and Y1Ba2Cu3Ox (YBCO) coated MgO substrates. Substrate temperature and oxygen pressure were varied to achieve ferroelectric films with a perovskite structure. Films grown on MgO had the perovskite structure with an epitaxial relationship with the MgO substrate. On the other hand, films grown on the YBCO/MgO substrate had an oriented structure to the surface normal with a misorientation in the plane parallel to the surface. The measured dielectric constant and loss tangent at 1 kHz were 670 and 0.05, respectively. The remnant polarization and coercive field were 42 μC/cm2 and 53 kV/cm. A large internal bias field (12 kV/cm) was observed in the as-deposited state of the undoped PZT films.

Optimization of Parameter Ranges for Composite Tape Winding Process Based on Sensitivity Analysis

NASA Astrophysics Data System (ADS)

Yu, Tao; Shi, Yaoyao; He, Xiaodong; Kang, Chao; Deng, Bo; Song, Shibo

2017-08-01

This study is focus on the parameters sensitivity of winding process for composite prepreg tape. The methods of multi-parameter relative sensitivity analysis and single-parameter sensitivity analysis are proposed. The polynomial empirical model of interlaminar shear strength is established by response surface experimental method. Using this model, the relative sensitivity of key process parameters including temperature, tension, pressure and velocity is calculated, while the single-parameter sensitivity curves are obtained. According to the analysis of sensitivity curves, the stability and instability range of each parameter are recognized. Finally, the optimization method of winding process parameters is developed. The analysis results show that the optimized ranges of the process parameters for interlaminar shear strength are: temperature within [100 °C, 150 °C], tension within [275 N, 387 N], pressure within [800 N, 1500 N], and velocity within [0.2 m/s, 0.4 m/s], respectively.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Jinsong; Dong, Qingfeng; Sao, Yuchuan

Continuous processes for fabricating a perovskite device are described that include using a doctor blade for continuously forming a perovskite layer and using a conductive tape lamination process to form an anode or a cathode layer on the perovskite device.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barasinski, Anaies; Leygue, Adrien; Poitou, Arnaud

The thermoplastic tape placement process offers the possibility of manufacturing large laminated composite parts with all kinds of geometries (double curved i.e.). This process is based on the fusion bonding of a thermoplastic tape on a substrate. It has received a growing interest during last years because of its non autoclave abilities.In order to control and optimize the quality of the manufactured part, we need to predict the temperature field throughout the processing of the laminate. In this work, we focus on a thermal modeling of this process which takes in account the imperfect bonding existing between the different layersmore » of the substrate by introducing thermal contact resistance in the model. This study is leaning on experimental results which inform us that the value of the thermal resistance evolves with temperature and pressure applied on the material.« less

Method of producing Pb-stabilized superconductor precursors and method of producing superconductor articles therefrom

DOEpatents

Kroeger, D.M.; Hsu, H.S.; Brynestad, J.

1995-03-07

Metal oxide superconductor powder precursors are prepared in an aerosol pyrolysis process. A solution of the metal cations is introduced into a furnace at 600--1,000 C for 0.1 to 60 seconds. The process produces micron to submicron size powders without the usual loss of the lead stabilizer. The resulting powders have a narrow particle size distribution, a small grain size, and are readily converted to a superconducting composition upon subsequent heat treatment. The precursors are placed in a metal body deformed to form a wire or tape and heated to form a superconducting article. The fine powders permit a substantial reduction in heat treatment time, thus enabling a continuous processing of the powders into superconducting wire, tape or multifilamentary articles by the powder-in-tube process. 3 figs.

Method of producing Pb-stabilized superconductor precursors and method of producing superconductor articles therefrom

DOEpatents

Kroeger, Donald M.; Hsu, Huey S.; Brynestad, Jorulf

1995-01-01

Metal oxide superconductor powder precursors are prepared in an aerosol pyrolysis process. A solution of the metal cations is introduced into a furnace at 600.degree.-1000.degree. C. for 0.1 to 60 seconds. The process produces micron to submicron size powders without the usual loss of the lead stabilizer. The resulting powders have a narrow particle size distribution, a small grain size, and are readily converted to a superconducting composition upon subsequent heat treatment. The precursors are placed in a metal body deformed to form a wire or tape and heated to form a superconducting article. The fine powders permit a substantial reduction in heat treatment time, thus enabling a continuous processing of the powders into superconducting wire, tape or multifilamentary articles by the powder-in-tube process.

Fabrication of ultrafast laser written low-loss waveguides in flexible As₂S₃ chalcogenide glass tape.

PubMed

Lapointe, Jerome; Ledemi, Yannick; Loranger, Sébastien; Iezzi, Victor Lambin; Soares de Lima Filho, Elton; Parent, Francois; Morency, Steeve; Messaddeq, Younes; Kashyap, Raman

2016-01-15

As2S3 glass has a unique combination of optical properties, such as wide transparency in the infrared region and a high nonlinear coefficient. Recently, intense research has been conducted to improve photonic devices using thin materials. In this Letter, highly uniform rectangular single-index and 2 dB/m loss step-index optical tapes have been drawn by the crucible technique. Low-loss (<0.15  dB/cm) single-mode waveguides in chalcogenide glass tapes have been fabricated using femtosecond laser writing. Optical backscatter reflectometry has been used to study the origin of the optical losses. A detailed study of the laser writing process in thin glass is also presented to facilitate a repeatable waveguide inscription recipe.

Asymmetry-symmetry transition of double-sided adhesive tapes

NASA Astrophysics Data System (ADS)

Yamaguchi, Tetsuo; Muroo, Hiroyuki; Sumino, Yutaka; Doi, Masao

2012-06-01

We report on the debonding process of a double-sided adhesive tape sandwiched between two glass plates. When the glass plates are separated from each other at a constant rate, a highly asymmetric extension of top and bottom adhesive layers and bending of the inner film are observed first. As the separation proceeds, the elongation of both layers becomes symmetric, and the inner film becomes flat again. When this happens, there appears a local maximum in the force-displacement curve. We explain this asymmetry-symmetry transition and discuss the role of the bimodal force-displacement relation of each adhesive layer. We also discuss the effect of the inner film thickness and the separation rate on the debonding behavior, which causes undesirable early detachment of the double-sided adhesive tape in a certain condition.

Technology and Development of Self-Reinforced Polymer Composites

NASA Astrophysics Data System (ADS)

Alcock, Ben; Peijs, Ton

In recent years there has been an increasing amount of interest, both commercially and scientifically, in the emerging field of "self-reinforced polymer composites". These materials, which are sometimes also referred to as "single polymer composites", or "all-polymer composites", were first conceived in the 1970s, and are now beginning to appear in a range of commercial products. While high mechanical performance polymer fibres or tapes are an obvious precursor for composite development, various different technologies have been developed to consolidate these into two- or three-dimensional structures. This paper presents a review of the various processing techniques that have been reported in the literature for the manufacture of self-reinforced polymer composites from fibres or tapes of different polymers, and so exploit the fibre or tape performance in a commercial material or product.

TM digital image products for applications. [computer compatible tapes

NASA Technical Reports Server (NTRS)

Barker, J. L.; Gunther, F. J.; Abrams, R. B.; Ball, D.

1984-01-01

The image characteristics of digital data generated by LANDSAT 4 thematic mapper (TM) are discussed. Digital data from the TM resides in tape files at various stages of image processing. Within each image data file, the image lines are blocked by a factor of either 5 for a computer compatible tape CCT-BT, or 4 for a CCT-AT and CCT-PT; in each format, the image file has a different format. Nominal geometric corrections which provide proper geodetic relationships between different parts of the image are available only for the CCT-PT. It is concluded that detector 3 of band 5 on the TM does not respond; this channel of data needs replacement. The empty bin phenomenon in CCT-AT images results from integer truncations of mixed-mode arithmetric operations.

Magnetic Tape Recording for the Eighties

NASA Technical Reports Server (NTRS)

Kalil, Ford (Editor)

1982-01-01

The practical and theoretical aspects of state-of-the-art magnetic tape recording technology are reviewed. Topics covered include the following: (1) analog and digital magnetic tape recording, (2) tape and head wear, (3) wear testing, (4) magnetic tape certification, (5) care, handling, and management of magnetic tape, (6) cleaning, packing, and winding of magnetic tape, (7) tape reels, bands, and packaging, (8) coding techniques for high-density digital recording, and (9) tradeoffs of coding techniques.

An Experimental Investigation of Damaged Arresting Gear Tapes for the Langley Aircraft Landing Dynamics Facility

NASA Technical Reports Server (NTRS)

Mason, Angela J.

1999-01-01

An experimental investigation was performed on damaged arresting gear tapes at the Langley Aircraft Landing Dynamics Facility. The arrestment system uses five pairs of tapes to bring the test carriage to a halt. The procedure used to determine when to replace the tapes consists of a close evaluation of each of the 10 tapes after each run. During this evaluation, each tape is examined thoroughly and any damage observed on the tape is recorded. If the damaged tape does not pass the inspection, the tape is replaced with a new one. For the past 13 years, the most commonly seen damage types are edge fray damage and transverse damage. Tests were conducted to determine the maximum tensile strength of a damaged arresting gear tape specimen. The data indicate that tapes exhibiting transverse damage can withstand higher loads than tapes with edge fray damage.

Rapid and semi-analytical design and simulation of a toroidal magnet made with YBCO and MgB 2 superconductors

DOE PAGES

Dimitrov, I. K.; Zhang, X.; Solovyov, V. F.; ...

2015-07-07

Recent advances in second-generation (YBCO) high-temperature superconducting wire could potentially enable the design of super high performance energy storage devices that combine the high energy density of chemical storage with the high power of superconducting magnetic storage. However, the high aspect ratio and the considerable filament size of these wires require the concomitant development of dedicated optimization methods that account for the critical current density in type-II superconductors. In this study, we report on the novel application and results of a CPU-efficient semianalytical computer code based on the Radia 3-D magnetostatics software package. Our algorithm is used to simulate andmore » optimize the energy density of a superconducting magnetic energy storage device model, based on design constraints, such as overall size and number of coils. The rapid performance of the code is pivoted on analytical calculations of the magnetic field based on an efficient implementation of the Biot-Savart law for a large variety of 3-D “base” geometries in the Radia package. The significantly reduced CPU time and simple data input in conjunction with the consideration of realistic input variables, such as material-specific, temperature, and magnetic-field-dependent critical current densities, have enabled the Radia-based algorithm to outperform finite-element approaches in CPU time at the same accuracy levels. Comparative simulations of MgB 2 and YBCO-based devices are performed at 4.2 K, in order to ascertain the realistic efficiency of the design configurations.« less

Fabrication of interface-modified ramp-edge junction on YBCO ground plane with multilayer structure

NASA Astrophysics Data System (ADS)

Wakana, H.; Adachi, S.; Kamitani, A.; Sugiyama, H.; Sugano, T.; Horibe, M.; Ishimaru, Y.; Tarutani, Y.; Tanabe, K.

2003-10-01

We examined the fabrication conditions to obtain high-quality ramp-edge Josephson junctions on a liquid-phase-epitaxy YBa 2Cu 3O y (LPE-YBCO) ground plane, in particular, focusing on the fabrication of a suitable insulating layer on the ground plane and the post-annealing conditions to load oxygen to the ground plane. A (LaAlO 3) 0.3-(SrAl 0.5Ta 0.5O 3) 0.7 (LSAT) insulating film on the ground planes exhibited a conductance ranging from 10 -4 to 10 -8 S after deposition of an upper superconducting film, suggesting existence of some leak paths through the LSAT insulating layer. By introducing approximately 30 nm thick SrTiO 3 (STO) buffer layers on both side of the LSAT insulating layer. We reproducibly obtained a conductance lower than 10 -8 S. The dielectric constant of the STO/LSAT/STO layer was 32, which was slightly larger than that of the single LSAT layer. It was found that a very slow cooling rate of 1.0 °C/h in oxygen was needed to fully oxidize the ground plane through the STO/LSAT/STO insulating layers, while the oxidation time could be effectively reduced by introducing via holes in the insulating layer at an interval of 200 μm. Ramp-edge junctions on LPE-YBCO ground planes with STO/LSAT/STO insulating layers exhibited a 1 σ-spread in Ic of 8% for 100-junction series-arrays and a sheet inductance of 0.7 pH/□ at 4.2 K.

Documentation for the machine-readable version of the thirteen color photometry of 1380 bright stars

NASA Technical Reports Server (NTRS)

Warren, W. H., Jr.; Roman, N. G.

1981-01-01

The magnetic tape version of the catalogue of thirteen-color photometry of 1380 bright stars, containing data on the 13 color medium narrow band photometric system is described. Observations of essentially all stars brighter than fifth visual magnitude north of delta = -20 deg and brighter than fourth visual magnitude south of delta = -20 deg are included. It is intended to enable users to read and process the tape without the common difficulties and uncertainties.

Thermomechanical Analysis of Shape-Memory Composite Tape Spring

NASA Astrophysics Data System (ADS)

Yang, H.; Wang, L. Y.

2013-06-01

Intelligent materials and structures have been extensively applied for satellite designs in order to minimize the mass and reduce the cost in the launch of the spacecraft. Elastic memory composites (EMCs) have the ability of high-strain packaging and shape-memory effect, but increase the parts and total weight due to the additional heating system. Shape-memory sandwich structures Li and Wang (J. Intell. Mater. Syst. Struct. 22(14), 1605-1612, 2011) can overcome such disadvantage by using the metal skin acting as the heating element. However, the high strain in the micro-buckled metal skin decreases the deployment efficiency. This paper aims to present an insight into the folding and deployment behaviors of shape-memory composite (SMC) tape springs. A thermomechanical process was analyzed, including the packaging deformation at an elevated temperature, shape frozen at the low temperature and shape recovery after reheating. The result shows that SMC tape springs can significantly decrease the strain concentration in the metal skin, as well as exhibiting excellent shape frozen and recovery behaviors. Additionally, possible failure modes of SMC tape springs were also analyzed.

Performance measurements and operational characteristics of the Storage Tek ACS 4400 tape library with the Cray Y-MP EL

NASA Technical Reports Server (NTRS)

Hull, Gary; Ranade, Sanjay

1993-01-01

With over 5000 units sold, the Storage Tek Automated Cartridge System (ACS) 4400 tape library is currently the most popular large automated tape library. Based on 3480/90 tape technology, the library is used as the migration device ('nearline' storage) in high-performance mass storage systems. In its maximum configuration, one ACS 4400 tape library houses sixteen 3480/3490 tape drives and is capable of holding approximately 6000 cartridge tapes. The maximum storage capacity of one library using 3480 tapes is 1.2 TB and the advertised aggregate I/O rate is about 24 MB/s. This paper reports on an extensive set of tests designed to accurately assess the performance capabilities and operational characteristics of one STK ACS 4400 tape library holding approximately 5200 cartridge tapes and configured with eight 3480 tape drives. A Cray Y-MP EL2-256 was configured as its host machine. More than 40,000 tape jobs were run in a variety of conditions to gather data in the areas of channel speed characteristics, robotics motion, time taped mounts, and timed tape reads and writes.

Materials Data on YbCo3B2 (SG:191) by Materials Project

DOE Data Explorer

Kristin Persson

2014-11-02

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

Data Analysis of a Space Experiment: Common Software Tackles Uncommon Task

NASA Technical Reports Server (NTRS)

Wilkinson, R. Allen

1998-01-01

Presented here are the software adaptations developed by laboratory scientists to process the space experiment data products from three experiments on two International Microgravity Laboratory Missions (IML-1 and IML-2). The challenge was to accommodate interacting with many types of hardware and software developed by both European Space Agency (ESA) and NASA aerospace contractors, where data formats were neither commercial nor familiar to scientists. Some of the data had been corrupted by bit shifting of byte boundaries. Least-significant/most-significant byte swapping also occurred as might be expected for the various hardware platforms involved. The data consisted of 20 GBytes per experiment of both numerical and image data. A significant percentage of the bytes were consumed in NASA formatting with extra layers of packetizing structure. It was provided in various pieces to the scientists on magnetic tapes, Syquest cartridges, DAT tapes, CD-ROMS, analog video tapes, and by network FIP. In this paper I will provide some science background and present the software processing used to make the data useful in the months after the missions.

An Atmospheric Tape Recorder: The Imprint of Tropical Tropopause Temperatures on Stratospheric Water Vapor

NASA Technical Reports Server (NTRS)

Mote, Philip W.; Rosenlof, Karen H.; McIntyre, Michael E.; Carr, Ewan S.; Gille, John C.; Holton, James R.; Kinnersley, Jonathan S.; Pumphrey, Hugh C.; Russell, James M., III; Waters, Joe W.

1996-01-01

We describe observations of tropical stratospheric water vapor q that show clear evidence of large-scale upward advection of the signal from annual fluctuations in the effective 'entry mixing ratio' q(sub E) of air entering the tropical stratosphere. In other words, air is 'marked,' on emergence above the highest cloud tops, like a signal recorded on an upward moving magnetic tape. We define q(sub E) as the mean water vapor mixing ratio, at the tropical tropopause, of air that will subsequently rise and enter the stratospheric 'overworld' at about 400 K. The observations show a systematic phase lag, increasing with altitude, between the annual cycle in q(sub E) and the annual cycle in q at higher altitudes. The observed phase lag agrees with the phase lag calculated assuming advection by the transformed Eulerian-mean vertical velocity of a q(sub E) crudely estimated from 100-hPa temperatures, which we use as a convenient proxy for tropopause temperatures. The phase agreement confirms the overall robustness of the calculation and strongly supports the tape recorder hypothesis. Establishing a quantitative link between q(sub E) and observed tropopause temperatures, however, proves difficult because the process of marking the tape depends subtly on both small- and large-scale processes. The tape speed, or large-scale upward advection speed, has a substantial annual variation and a smaller variation due to the quasi-biennial oscillation, which delays or accelerates the arrival of the signal by a month or two in the middle stratosphere. As the tape moves upward, the signal is attenuated with an e-folding time of about 7 to 9 months between 100 and 50 hPa and about 15 to 18 months between 50 and 20 hPa, constraining possible orders of magnitude both of vertical diffusion K(sub z) and of rates of mixing in from the extratropics. For instance, if there were no mixing in, then K(sub z) would be in the range 0.03-0.09 m(exp 2)/s; this is an upper bound on K(sub z).

Playback Station #2 for Cal Net and 5-day-recorder tapes

USGS Publications Warehouse

Eaton, Jerry P.

1978-01-01

A second system (Playback Station #2) has been set up to play back Cal Net 1" tapes and 5-day-recorder 1/2" tapes. As with the first playback system (Playback Station #1) the tapes are played back on a Bell and Howell VR3700B tape deck and the records are written out on a 16-channel direct-writing Siemens "0scillomink." Separate reproduce heads, tape guides, and tape tension sensor rollers are required for playing back 111 tapes and 1/2" tapes, but changing these tape deck components is a simple task that requires only a few minutes. The discriminators, patch panels, selector switches, filters, time code translators, and signal conditioning circuits for the time code translators and for the tape-speed-compensation signal are all mounted in an equipment rack that stands beside the playback tape deck. Changing playback speeds (15/16 ips or 3 3/4 ips) or changing from Cal Net tapes to 5-day-recorder tapes requires only flipping a few switches and/or changing a few patch cables on the patch panel (in addition to changing the reproduce heads, etc., to change from 1" tape to 1/2" tape). For the Cal Net tapes, the system provides for playback of 9 data channels (680 Hz thru 3060 Hz plus 400 Hz) and 3 time signals (IRIG-E, IRIG-C, and WWVB) at both 15/16 ips (x1 speed) and 3 3/4 ips (x4 speed). Available modes of compensation (using either a 4688 Hz reference or a 3125 Hz reference) are subtractive, capstan, capstan plus subtractive, or no compensation.

Method for making high-critical-current-density YBa.sub.2 Cu.sub.3 O.sub.7 superconducting layers on metallic substrates

DOEpatents

Feenstra, Roeland; Christen, David; Paranthaman, Mariappan

1999-01-01

A method is disclosed for fabricating YBa.sub.2 Cu.sub.3 O.sub.7 superconductor layers with the capability of carrying large superconducting currents on a metallic tape (substrate) supplied with a biaxially textured oxide buffer layer. The method represents a simplification of previously established techniques and provides processing requirements compatible with scale-up to long wire (tape) lengths and high processing speeds. This simplification has been realized by employing the BaF.sub.2 method to grow a YBa.sub.2 Cu.sub.3 O.sub.7 film on a metallic substrate having a biaxially textured oxide buffer layer.

Reevaluation of the non-lesional dry skin in atopic dermatitis by acute barrier disruption: an abnormal permeability barrier homeostasis with defective processing to generate ceramide.

PubMed

Sugiura, Ayumi; Nomura, Tsuyoshi; Mizuno, Atsuko; Imokawa, Genji

2014-07-01

Atopic dermatitis is characterized by disruption of the cutaneous barrier due to reduced ceramide levels even in non-lesional dry skin. Following further acute barrier disruption by repeated tape strippings, we re-characterized the non-lesional dry skin of subjects with atopic dermatitis, which shows significantly reduced levels of barrier function and ceramide but not of beta-glucocerebrosidase activity. For the first time, we report an abnormal trans-epidermal water loss homeostasis in which delayed recovery kinetics of trans-epidermal water loss occurred on the first day during the 4 days after acute barrier disruption compared with healthy control skin. Interestingly, whereas the higher ceramide level in the stratum corneum of healthy control skin was further significantly up-regulated at 4 days post-tape stripping, the lower ceramide level in the stratum corneum of subjects with atopic dermatitis was not significantly changed. In a parallel study, whereas beta-glucocerebrosidase activity at 4 days post-tape stripping was significantly up-regulated in healthy control skin compared with before tape stripping, the level of that activity remained substantially unchanged in atopic dermatitis. These findings indicate that subjects with atopic dermatitis have a defect in sphingolipid-metabolic processing that generates ceramide in the interface between the stratum corneum and the epidermis. The results also support the notion that the continued disruption of barrier function in atopic dermatitis non-lesional skin is associated with the impaired homeostasis of a ceramide-generating process, which underscores an atopy-specific inflammation-triggered ceramide deficiency that is distinct from other types of dermatitis.

An economic analysis for optimal distributed computing resources for mask synthesis and tape-out in production environment

NASA Astrophysics Data System (ADS)

Cork, Chris; Lugg, Robert; Chacko, Manoj; Levi, Shimon

2005-06-01

With the exponential increase in output database size due to the aggressive optical proximity correction (OPC) and resolution enhancement technique (RET) required for deep sub-wavelength process nodes, the CPU time required for mask tape-out continues to increase significantly. For integrated device manufacturers (IDMs), this can impact the time-to-market for their products where even a few days delay could have a huge commercial impact and loss of market window opportunity. For foundries, a shorter turnaround time provides a competitive advantage in their demanding market, too slow could mean customers looking elsewhere for these services; while a fast turnaround may even command a higher price. With FAB turnaround of a mature, plain-vanilla CMOS process of around 20-30 days, a delay of several days in mask tapeout would contribute a significant fraction to the total time to deliver prototypes. Unlike silicon processing, masks tape-out time can be decreased by simply purchasing extra computing resources and software licenses. Mask tape-out groups are taking advantage of the ever-decreasing hardware cost and increasing power of commodity processors. The significant distributability inherent in some commercial Mask Synthesis software can be leveraged to address this critical business issue. Different implementations have different fractions of the code that cannot be parallelized and this affects the efficiency with which it scales, as is described by Amdahl"s law. Very few are efficient enough to allow the effective use of 1000"s of processors, enabling run times to drop from days to only minutes. What follows is a cost aware methodology to quantify the scalability of this class of software, and thus act as a guide to estimating the optimal investment in terms of hardware and software licenses.

Digital methods of recording color television images on film tape

NASA Astrophysics Data System (ADS)

Krivitskaya, R. Y.; Semenov, V. M.

1985-04-01

Three methods are now available for recording color television images on film tape, directly or after appropriate finish of signal processing. Conventional recording of images from the screens of three kinescopes with synthetic crystal face plates is still most effective for high fidelity. This method was improved by digital preprocessing of brightness color-difference signal. Frame-by-frame storage of these signals in the memory in digital form is followed by gamma and aperture correction and electronic correction of crossover distortions in the color layers of the film with fixing in accordance with specific emulsion procedures. The newer method of recording color television images with line arrays of light-emitting diodes involves dichromic superposing mirrors and a movable scanning mirror. This method allows the use of standard movie cameras, simplifies interlacing-to-linewise conversion and the mechanical equipment, and lengthens exposure time while it shortens recording time. The latest image transform method requires an audio-video recorder, a memory disk, a digital computer, and a decoder. The 9-step procedure includes preprocessing the total color television signal with reduction of noise level and time errors, followed by frame frequency conversion and setting the number of lines. The total signal is then resolved into its brightness and color-difference components and phase errors and image blurring are also reduced. After extraction of R,G,B signals and colorimetric matching of TV camera and film tape, the simultaneous R,B, B signals are converted from interlacing to sequential triades of color-quotient frames with linewise scanning at triple frequency. Color-quotient signals are recorded with an electron beam on a smoothly moving black-and-white film tape under vacuum. While digital techniques improve the signal quality and simplify the control of processes, not requiring stabilization of circuits, image processing is still analog.

Immediate Effects of Ankle Balance Taping with Kinesiology Tape for Amateur Soccer Players with Lateral Ankle Sprain: A Randomized Cross-Over Design

PubMed Central

Kim, Myoung Kwon; Shin, Young Jun

2017-01-01

Background The objective of this study was to investigate the immediate effect on gait function when ankle balance taping is applied to amateur soccer players with lateral ankle sprain. Material/Methods A cross-over randomized design was used. Twenty-two soccer players with an ankle sprain underwent 3 interventions in a random order. Subjects were randomly assigned to ankle balance taping, placebo taping, and no taping groups. The assessment was performed using the GAITRite portable walkway system, which records the location and timing of each footfall during ambulation. Results Significant differences were found in the velocity, step length, stride length, and H-H base support among the 3 different taping methods (p<0.05). The ankle balance taping group showed significantly greater velocity, step length, and stride length in comparison to the placebo and no taping group. The ankle balance taping group showed a statistically significant decrease (p<0.05) in the H-H base support compared to the placebo and no taping groups, and the placebo group showed significantly greater velocity in comparison to the no taping group (p<0.05). Conclusions We conclude that ankle balance taping that uses kinesiology tape instantly increased the walking ability of amateur soccer players with lateral ankle sprain. Therefore, ankle balance taping is a useful alternative to prevent and treat ankle sprain of soccer players. PMID:29158472

Ceramic-metal composites prepared via tape casting and melt infiltration methods

NASA Astrophysics Data System (ADS)

Kim, Hyun Jun

Melt infiltration of preforms prepared by tape casting and lamination has been accomplished using a short-time infiltration process that significantly suppresses reaction product formation. For layered materials produced via infiltration of laminated ceramic tapes, of particular interest is the effect that a large change in microstructure has on infiltration, phase formation, and mechanical properties. Hardness of the fine scale composite layers is approximately three times higher than coarse scale layers, due to greater strength of the fine B4C network. Fractography showed that crack propagation occurred by brittle fracture of the carbide and ductile extension of the metal. Despite large differences in hardness, the fracture mode of the fine and coarse scale microstructures appears identical. Fluid flow modeling for tape casting was conducted with a Newtonian slurry under a parallel blade, and the effect of beveling the blade based on a one dimensional flow model is shown. The discussion on slurry deformation after the blade exit suggests that the mode of slurry deformation depends on the relative importance of the pressure gradient and wall shear and that the existence of zero shear plane might have a negative effect on particle alignment in the tape. The analysis of the flow under a beveled blade predicts that this configuration is more advantageous than the parallel blade for productivity and parallel blade is better for producing uniform particle alignment and thinner tape. Also, the one dimensional flow model for the beveled blade is shown to be a valid approximation of the fluid behavior below a blade angle of 45 degrees. The flow visualization study on tape casting was conducted with a transparent apparatus and model slurry. Most investigators have concluded that the shear stress between the doctor blade and moving carrier causes the particle alignment, but, according to the result of visualization experiment, some degree of particle alignment is already established in the reservoir. The fluid flow concept of tape casting is incorporated with a metal infiltration technique to prepare the ceramic-metal composites with tailored porosity and pore orientation. Boron carbide-aluminum system was used to prepare the composites, and its stiffness constants were investigated. The aligned metal ligaments rarely affect the stiffness constant anisotropy which appears to be caused by tape casting operation.

Basic difference between brain and computer: integration of asynchronous processes implemented as hardware model of the retina.

PubMed

Przybyszewski, Andrzej W; Linsay, Paul S; Gaudiano, Paolo; Wilson, Christopher M

2007-01-01

There exists a common view that the brain acts like a Turing machine: The machine reads information from an infinite tape (sensory data) and, on the basis of the machine's state and information from the tape, an action (decision) is made. The main problem with this model lies in how to synchronize a large number of tapes in an adaptive way so that the machine is able to accomplish tasks such as object classification. We propose that such mechanisms exist already in the eye. A popular view is that the retina, typically associated with high gain and adaptation for light processing, is actually performing local preprocessing by means of its center-surround receptive field. We would like to show another property of the retina: The ability to integrate many independent processes. We believe that this integration is implemented by synchronization of neuronal oscillations. In this paper, we present a model of the retina consisting of a series of coupled oscillators which can synchronize on several scales. Synchronization is an analog process which is converted into a digital spike train in the output of the retina. We have developed a hardware implementation of this model, which enables us to carry out rapid simulation of multineuron oscillatory dynamics. We show that the properties of the spike trains in our model are similar to those found in vivo in the cat retina.

Superconductivity in Russia: Update and prospects

NASA Technical Reports Server (NTRS)

Ozhogin, V.

1995-01-01

The research projects and new technological developments that have occured in Russia are highlighted in this document. Some of the research discussed includes: x-ray structure analysis of YBCO superconducting single crystals and accompanying phase transformations; the role of electron-electron interaction in High Temperature Superconductors (HTSC); the formation of Cooper pairs in crystals; the synthesis and research on a new family of superconductors based on complex copper and mercury oxides (HgBa2CuO4 + alpha and HgBa2CaCu2O6 + alpha); methods for the extraction of higher (up to C200) fullerenes and metalfullerenides has been developed; and process of production of Josephson junctions and development of SQUID's.

PHOTOELECTRIC CONTROL FOR TAPE POSITIONING

DOEpatents

Woody, J.W. Jr.

1961-07-25

A control system is described for producing control impulses which may be used to start, stop, and position a magnetic tape with respect to a transducer, and to locate discrete areas on the tape. Means are provided for positive identification of data blocks, exact positioning of the tape under the magnetic head, drive in either direction, accurate skip-over of imperfect regions of the tape, stopping the tape if equipment malfunction results in a failure to detect the block-identifying signals, and starting and stopping those parts of the tape between of the tape drive clutches.

The Effect of Patellar Taping on Squat Depth and the Perception of Pain in People with Anterior Knee Pain

PubMed Central

Clifford, Amanda M.; Harrington, Elaine

Patellar taping is a treatment adjunct commonly used in the management of anterior knee pain. The aim of this cross sectional study was to investigate the effects of medial glide patellar taping on sagittal plane lower-limb joint kinematics and knee pain during a unilateral squat in a symptomatic population complaining of anterior knee pain. Ten participants with a history of unilateral or bilateral anterior knee pain were included in the study. Subjects were required to squat on the symptomatic leg under three conditions: placebo tape, patellar tape and no tape. Kinematic data was recorded using the CODA mpx64 motion analysis system and subjects’ pain was assessed using the Numerical Rating Scale. Patellar taping resulted in a significantly greater single-legged squat depth compared to placebo tape (p=0.008) and no tape (p=0.001) and a statistically significant reduction in pain during a squat compared to placebo tape (p=0.001) or no tape (p=0.001). Significant differences were not identified for maximum knee flexion in the patella taping compared to the no tape condition. This study may have significant clinical implications as participants reported less pain and alterations in sagittal plane movement following the application of patellar tape. PMID:24146711

The spectroscopic detection of exogenous material in fingerprints after development with powders and recovery with adhesive lifters.

PubMed

West, Matthew J; Went, Michael J

2008-01-15

The application of powders to fingerprints has long been established as an effective and reliable method for developing latent fingerprints. The powders adhere to the ridge pattern of the fingerprint only, thus allowing the image to be visualised. Fingerprints developed in situ at a crime scene routinely undergo lifting with specialist tapes to facilitate subsequent laboratory analysis. As with all recovered evidence these samples would be stored in evidence bags to allow secure transit from the scene to the laboratory and also to preserve the chain of evidence. In this paper, the application of Raman spectroscopy for the analysis of exogenous material in latent fingerprints is reported for contaminated fingerprints that had been treated with powders and also subsequently lifted with adhesive tapes. A selection of over the counter (OTC) analgesics were used as samples for the analysis and contaminated fingerprints were deposited on clean glass slides. The application of aluminium or iron based powders to contaminated fingerprints did not interfere with the Raman spectra obtained for the contaminants. In most cases background fluorescence attributed to the sebaceous content of the latent fingerprint was reduced by the application of the powder thus reducing spectral interference. Contaminated fingerprints developed with powders and then lifted with lifting tapes were also examined. The combination of these two techniques did not interfere with the successful analysis of exogenous contaminants by Raman spectroscopy. The lifting process was repeated using hinge lifters. As the hinge lifters exhibited strong Raman bands the spectroscopic analysis was more complex and an increase in the number of exposures to the detector allowed for improved clarification. Raman spectra of developed and lifted fingerprints recorded through evidence bags were obtained and it was found that the detection process was not compromised in any way. Although the application of powders did not interfere with the detection process the time taken to locate the contaminant was increased due to the physical presence of more material within the fingerprint. The presence of interfering Raman bands from lifting tapes is another potential complication. This, however, could be removed by spectral subtraction or by the choice of lifting tapes that have only weak Raman bands.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abushakra, Bass

The aging tests conducted so far showed that duct tape tends to degrade in its performance as the joint it is applied to requires a geometrical description of a higher number of space dimensions (1-D, 2-D, 3-D). One-dimensional joints are the easiest to seal with duct tape, and thus the least to experience failure. Two-dimensional joints, such as the flexible duct core-to-collar joints tested in this study, are less likely to fail than three-dimensional collar-to-plenum joints, as the shrinkage could have a positive effect in tightening the joint. Three-dimensional joints are the toughest to seal and the most likely tomore » experience failure. The 2-D flexible duct core-to-collar joints passed the six-month period of the aging test in terms of leakage, but with the exception of the foil-butyl tape, showed degradation in terms hardening, brittleness, partial peeling, shrinkage, wrinkling, delamination of the tape layers, flaking, cracking, bubbling, oozing and discoloration. The baking test results showed that the failure in the duct tape joints could be attributed to the type of combination of the duct tape and the material it is applied to, as the duct tape behaves differently with different substrates. Overall, the foil-butyl tape (Tape 4) had the best results, while the film tape (Tape 3) showed the most deterioration. The conventional duct tapes tested (Tape 1 and Tape 2) were between these two extremes, with Tape 2 performing better than Tape 1. Lastly, we found that plastic straps became discolored and brittle during the tests, and a couple of straps broke completely. Therefore, we recommend that clamping the duct-taped flexible core-to-collar joints should be done with metallic adjustable straps.« less

Archiving of Planetary Ring Data

NASA Technical Reports Server (NTRS)

Elliot, James L.

2001-01-01

Stellar occultation data provide our only Earth-based means of probing planetary rings at kilometer spatial resolution. The occultation data archive at MIT contains original data and analysis products of stellar occultations by the ring systems of the planets Jupiter, Saturn, Uranus, and Neptune observed by members of the group (and other groups) from 1977 to the present. During this time period, several media have been used to record and store the original and processed data: (1) chart records; (2) printed output, (3) audio reel tape; (4) audio cassette tape; (5) 7-track, 1/2-inch computer tape; (6) 9-track, 1/2-inch computer tape at 800, 1600, and 6250 bpi; (7) NOVA disk platters (2.5 and 5.0 Mbyte); (8) write once optical disks; (9) punched cards; and (10) read-write optical disks. With the rapid change of computer technology over this time period, some of these media have become not only obsolete, but nearly extinct. In particular, it has become nearly impossible to find any facilities that can still read 800 bpi tapes, which contain the only copies of several important data sets for the ring system of Uranus. In particular, we have an extensive ring data collection that includes data sets for the following Uranian ring occultations: U0, U11, U12, U13, U14, U25, U17, and U36.

Use of binaural beat tapes for treatment of anxiety: a pilot study of tape preference and outcomes.

PubMed

Le Scouarnec, R P; Poirier, R M; Owens, J E; Gauthier, J; Taylor, A G; Foresman, P A

2001-01-01

Recent studies and anecdotal reports suggest that binaural auditory beats can affect mood, performance on vigilance tasks, and anxiety. To determine whether mildly anxious people would report decreased anxiety after listening daily for 1 month to tapes imbedded with tones that create binaural beats, and whether they would show a definite tape preference among 3 tapes. A 1-group pre-posttest pilot study. Patients' homes. A volunteer sample of 15 mildly anxious patients seen in the Clinique Psyché, Montreal, Quebec. Participants were asked to listen at least 5 times weekly for 4 weeks to 1 or more of 3 music tapes containing tones that produce binaural beats in the electroencephalogram delta/theta frequency range. Participants also were asked to record tape usage, tape preference, and anxiety ratings in a journal before and after listening to the tape or tapes. Anxiety ratings before and after tape listening, pre- and post-study State-Trait Anxiety Inventory scores, and tape preferences documented in daily journals. Listening to the binaural beat tapes resulted in a significant reduction in the anxiety score reported daily in patients' diaries. The number of times participants listened to the tapes in 4 weeks ranged from 10 to 17 (an average of 1.4 to 2.4 times per week) for approximately 30 minutes per session. End-of-study tape preferences indicated that slightly more participants preferred tape B, with its pronounced and extended patterns of binaural beats, over tapes A and C. Changes in pre- and posttest listening State-Trait Anxiety Inventory scores trended toward a reduction of anxiety, but these differences were not statistically significant. Listening to binaural beat tapes in the delta/theta electroencephalogram range may be beneficial in reducing mild anxiety. Future studies should account for music preference among participants and include age as a factor in outcomes, incentives to foster tape listening, and a physiologic measure of anxiety reduction. A controlled trial that includes binaural beat tapes as an adjunctive treatment to conventional therapy for mild anxiety may be warranted.

Materials, devices, techniques, and applications for Z-plane focal plane array technology II; Proceedings of the Meeting, San Diego, CA, July 12, 13, 1990

NASA Astrophysics Data System (ADS)

Carson, John C.

1990-11-01

Various papers on materials, devices, techniques, and applications for X-plane focal plane array technology are presented. Individual topics addressed include: application of Z-plane technology to the remote sensing of the earth from GEO, applications of smart neuromorphic focal planes, image-processing of Z-plane technology, neural network Z-plane implementation with very high interconnection rates, using a small IR surveillance satellite for tactical applications, establishing requirements for homing applications, Z-plane technology. Also discussed are: on-array spike suppression signal processing, algorithms for on-focal-plane gamma circumvention and time-delay integration, current HYMOSS Z-technology, packaging of electrons for on- and off-FPA signal processing, space/performance qualification of tape automated bonded devices, automation in tape automated bonding, high-speed/high-volume radiometric testing of Z-technology focal planes, 128-layer HYMOSS-module fabrication issues, automation of IRFPA production processes.

A novel processing platform for post tape out flows

NASA Astrophysics Data System (ADS)

Vu, Hien T.; Kim, Soohong; Word, James; Cai, Lynn Y.

2018-03-01

As the computational requirements for post tape out (PTO) flows increase at the 7nm and below technology nodes, there is a need to increase the scalability of the computational tools in order to reduce the turn-around time (TAT) of the flows. Utilization of design hierarchy has been one proven method to provide sufficient partitioning to enable PTO processing. However, as the data is processed through the PTO flow, its effective hierarchy is reduced. The reduction is necessary to achieve the desired accuracy. Also, the sequential nature of the PTO flow is inherently non-scalable. To address these limitations, we are proposing a quasi-hierarchical solution that combines multiple levels of parallelism to increase the scalability of the entire PTO flow. In this paper, we describe the system and present experimental results demonstrating the runtime reduction through scalable processing with thousands of computational cores.

STS-37: TCDT Pad B Atlantis GRO (2 of 3)

NASA Technical Reports Server (NTRS)

1991-01-01

Live footage shows the remaining two crewmembers of STS-37, Mission Specialists Jerry L. Ross, and Jay Apt, entering the White Room, putting on their life preservation vest, and then entering the launch vehicle. Video playbacks, of the crew during the earlier stage of the Terminal Countdown and Demonstration Test, and the processing of the primary payload (Gamma Ray Observatory) are shown. Scenes showing the arrival of Ross at Kennedy Space Center in the T-38 aircraft, the crew on the launch complex during familiarization activities, and training with the M113 vehicle are presented. Also shown are some beautiful panoramic views of the shuttle on the pad. This is tape 2 of 3. Tape 1 has a report # of NONP-NASA-VT-2000013416, and tape 3 has a report # of NONP-NASA-VT-2000013418.

Laser shock peening studies on SS316LN plate with various sacrificial layers

NASA Astrophysics Data System (ADS)

Yella, Pardhu; Venkateswarlu, P.; Buddu, Ramesh K.; Vidyasagar, D. V.; Sankara Rao, K. Bhanu; Kiran, P. Prem; Rajulapati, Koteswararao V.

2018-03-01

Laser shock peening (LSP) has been utilized to modify the surface characteristics of SS316LN plates of 6 mm thickness. Laser pulse widths employed are 30 ps and 7 ns and the laser energy was varied in the range 5-90 mJ. Peening was performed in direct ablation mode as well as with various sacrificial layers such as black paint, transparent adhesive tape and absorbing adhesive tape. The surface characteristics were greatly influenced by the type of sacrificial layer employed. The average surface roughness values are about 0.4 μm when the black paint and transparent adhesive tape were used as sacrificial layers. In contrast to this, using absorbent adhesive tape as a sacrificial layer has resulted in an average surface roughness of about 0.04 μm. Irrespective of pulse durations (30 ps or 7 ns), absorbent adhesive tape has always resulted in compressive residual stresses whereas other layers appear to be not that effective. In case of 30 ps pulse, as the laser energy was increased from 5 mJ to 25 mJ, there was a texture observed in (111) reflection of X-ray diffractograms and the center of the peak has also gradually shifted to left. X-ray line profile analysis suggests that with the increase in laser energy, lattice microstrain also has increased. This lattice microstrain appears to be resulting from the increased dislocation density in the peened sample as evidenced during transmission electron microscopic investigations. Cross-sectional scanning electron microscopy performed on peened samples suggests that absorbing adhesive tape brings no surface damage to the samples whereas other sacrificial layers have resulted in some surface damage. Based on all these structural and microstructural details, it is recommended that absorbent tape could be used as a sacrificial layer during LSP process which induces surface residual stresses with no damage to the sample surface.

Estimation of hysteretic losses for MgB2 tapes under the operating conditions of a generator

NASA Astrophysics Data System (ADS)

Vargas-Llanos, Carlos Roberto; Zermeño, Víctor M. R.; Sanz, Santiago; Trillaud, Frederic; Grilli, Francesco

2016-03-01

Hysteretic losses in the MgB2 wound superconducting coils of a 550 kW synchronous hybrid scaled generator were estimated as part of the European project SUPRAPOWER led by the Spanish Fundación Tecnalia Research & Innovation. Particular interest was given to the losses caused by the magnetic flux ripples in the rotor coils originating from the conventional stator during nominal operation. To compute these losses, a 2D finite element analysis was conducted and Maxwell’s equations written in the H-formulation were solved considering the nonlinear material properties of the conductor materials. The modeled tapes are made of multiple MgB2 filaments embedded in a Ni matrix and soldered to a high purity copper strip and insulated with Dacron braid. Three geometrical models of single tape cross sections of decreasing complexity were studied: (1) the first model reproduced closely the actual cross section obtained from tape micrographs. (2) The second model was obtained from the computed elasto-plastic deformation of a round Ni wire. (3) The third model was based on a simplified cross section with the superconducting filaments bundled in a single elliptical bulky structure. The last geometry allowed the validation of the modeling technique by comparing numerical losses with results from well-established analytical expressions. Additionally, the following cases of filament transpositions of the multi-filamentary tape were studied: no transposition, partial and full transposition; thereby improving understanding of the relevance of the tape fabrication process on the magnitude of the determination of ac losses. Finally, choosing the right level of geometrical detail, the following operational regimes of the machine and its impact on individual superconducting tape losses in the rotor were studied: bias-dc current, ramping current under ramping background field and magnetic flux ripples under dc background current and field.

Tape transport mechanism

DOEpatents

Groh, Edward F.; McDowell, William; Modjeski, Norbert S.; Keefe, Donald J.; Groer, Peter

1979-01-01

A device is provided for transporting, in a stepwise manner, tape between a feed reel and takeup reel. An indexer moves across the normal path of the tape displacing it while the tape on the takeup reel side of the indexer is braked. After displacement, the takeup reel takes up the displaced tape while the tape on the feed reel side of the indexer is braked, providing stepwise tape transport in precise intervals determined by the amount of displacement caused by the indexer.

Fermi-surface reconstruction by stripe order in cuprate superconductors

NASA Astrophysics Data System (ADS)

Laliberté, Francis

2012-02-01

The origin of pairing in a superconductor resides in the underlying normal state. In the cuprate high-temperature superconductor YBCO, application of a magnetic field to suppress superconductivity reveals a ground state that appears to break the translational symmetry of the lattice, pointing to some density-wave order [1,2,3]. In another cuprate, Eu-LSCO, the onset of stripe order - a modulation of spin and charge densities - at low temperature is well established [4]. By a comparative study of thermoelectric transport in the cuprates YBCO and Eu-LSCO, we show that the two materials exhibit a very similar process of Fermi-surface reconstruction as a function of temperature and doping [5,6]. This strongly suggests that Fermi-surface reconstruction is caused by stripe order in both cases, compelling evidence that stripe order is a generic tendency of hole-doped cuprates.[4pt] Work done in collaboration with J. Chang, N. Doiron-Leyraud, E. Hassinger, R. Daou, D. LeBoeuf, M. Rondeau, B. J. Ramshaw, R. Liang, D. A. Bonn, W. N. Hardy, S. Pyon, T. Takayama, H. Takagi, I. Sheikin, L. Malone, C. Proust, K. Behnia and L. Taillefer.[4pt] [1] N. Doiron-Leyraud et al., Nature 447, 565 (2007).[0pt] [2] D. LeBoeuf et al., Nature 450, 533 (2007).[0pt] [3] D. LeBoeuf et al., Phys. Rev. B 83, 054506 (2011).[0pt] [4] J. Fink et al., Phys. Rev. B 83, 092503 (2011).[0pt] [5] J. Chang et al., Phys. Rev. Lett. 104, 057005 (2010).[0pt] [6] F. Lalibert'e et al., Nat. Commun. 2, 432 (2011).

Transport properties of YBa2Cu3Ox /La0.67Sr0.33MnO3 nanostrips and YBa2Cu3Ox/La0.67Sr0.33MnO3/YBa2Cu3Ox nanojunctions

NASA Astrophysics Data System (ADS)

Štrbík, V.; Beňačka, Š.; Gaži, Š.; Španková, M.; Šmatko, V.; Chromik, Š.; Gál, N.; Knoška, J.; Sojková, M.; Pisarčík, M.

2016-03-01

A metallic ferromagnet (F) in proximity with a superconductor (S) can transport supercurrent on a long distance through conversion of opposite-spin singlet Cooper pairs (CP) into equal-spin triplet CP (long range triplet component, LRTC), which are not broken by the exchange energy of F. The optimal conditions for the conversion are yet to be clarified; however, it is accepted that the key point to this process include high interface transparency and magnetic inhomogeneity at the SF interface. The aim of our paper is to study SF nanostrips (length of about 1500 nm and width down to 300 nm) and lateral SFS nanojunctions based on high critical temperature YBa2Cu3Ox (YBCO) and half-metallic La0.67Sr0.33MnO3 (LSMO) thin films. We applied a focused Ga+ ion beam (FIB) for patterning the SF nanostrips, as well as lateral SFS nanojunctions, by creating a slot in the nanostrip after removing the YBCO film in the slot along a length of about 200 nm. The temperature dependences of the samples resistance R(T) show critical temperature TCn ≈ 89 K of the SF nanostrips; however, the SFS nanojunctions at T < TCn show a residual resistance R < 100 Ω corresponding to a dirty LSMO (ρ≈ 10 mΩ cm) in the slot. The LRTC was not observed in our lateral SFS nanojunctions until now.