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A Rutherford cabling machine is designed and manufactured for Bi-2212 strands. Filaments number and Ag ratio of Bi2212/Ag wires are examined in order to increase the critical current properties of Bi-2212/Ag wires.

The effect of filament configuration and heat treatment of Bi2212/Ag round wire with low Ag ratio on the engineering critical current density is analyzed. The effects of maximum process temperature and soaking time and average filament diameter on the critical current density are examined.

The damage behavior and the bending strain effect on the critical current ([I.sub.c]) in multifilamentary Bi-2223 superconductor tapes are examined. The Bi-2223 tapes have showed different [I.sub.c] degradation behavior that has depended upon the geometry and ratio of reinforcement to superconductor adopted.

The article discusses the properties of the Tm[Ba.sub.2][Cu.sub.3][O.sub.7-x] superconducting thin films that are grown by the method of pulsed laser deposition.

The study describes the critical current degradation behavior in the long length YBCO coated conductors that are subjected to torsional strain. The critical current is found to degrade gradually and slowly in these films.

The importance and the effects of different filament numbers on the workability and critical current density of Bi-2212/Ag superconducting wires are observed. The results show that the critical current density increases in proportion with the wire's filaments number.

Reporting the bending strain on the critical current [I(sub c)] in Ag alloy/Bi-2223 superconducting tapes was investigated at 77 K. The I(sub c) degradation behavior in Bi-2223 tapes under hard bending obtained by a newly devised sample mounting procedure showed nearly the same extent of scattering as easy bending.

Discussing the fabrication of double-pancake coils of 19- multifilamentary Bi-2223 tape and evaluated the current carrying capacity of joined tape and decay characteristics, joint resistance and n-values of the pancake coils is presented. It is observed that the properties of joined tapes and pancake coils are significantly dependent on the joining methods such as resistive- and superconducting-joint methods.

High gradient magnetic separation (HGMS) system was used for removing suspended solid (SS) in coolant for hot rolling process. Results suggest that the removing ratio of [Fe.sub.3] [O.sub.4] fine particles in artificial wastewater was more than 99 percent after four times of repetition of magnetic separation.

Long-length, high-temperature superconducting (HTS) wires capable of carrying high critical current, Ic, are required for a wide range of applications. Here, we report extremely high performance HTS wires based on 5 mm thick SmBa2Cu3O7 - δ (SmBCO) single layer films on textured metallic templates. SmBCO layer wires over 20 meters long were deposited by a cost-effective, scalable co-evaporation process using a batch-type drum in a dual chamber. All deposition parameters influencing the composition, phase, and texture of the films were optimized via a unique combinatorial method that is broadly applicable for co-evaporation of other promising complex materials containing several cations. Thick SmBCO layers deposited under optimized conditions exhibit excellent cube-on-cube epitaxy. Such excellent structural epitaxy over the entire thickness results in exceptionally high Ic performance, with average Ic over 1,000 A/ cm-width for the entire 22 meter long wire and maximum Ic over 1,500 A/cm-width for a short 12 cm long tape. The Ic values reported in this work are the highest values ever reported from any lengths of cuprate-based HTS wire or conductor. [ABSTRACT FROM AUTHOR]

Effect of filament configuration and heat treatment of Bi2212/Ag round wire with low Ag ratio on the engineering critical current density (Je) was reported. We have fabricated 55 x 7, 85 x 7, and 121 x 7 wires with different Ag ratio and evaluated Je at various wire diameters. We have also changed the parameters of heat treatment. The effects of maximum process temperature (Tmax,) and soaking time at Tmax and average filament diameter on the Je were also studied. 121 x 7 wire of 0.95 mm diameter heat-treated at Tmax = 888° C showed Je of 858 A/mm2 at 4.2 K, 0 T. [ABSTRACT FROM AUTHOR]

TmBa2Cu3O7-x films which is one of the (Rare earth)Ba2Cu3O7-x high temperature superconductors with small ionic radius of rare earth element, were deposited on STO (100) single crystal substrates and Y2O3/YSZ/CeO2 buffered metal substrates by pulsed laser deposition. The Jc (77 K) and the value of onset TC of TmBCO thin film on STO substrate was 4.5 MA/cm2 and 86 K, respectively. The JC of TmBCO coated conductor on metal substrate was 1 MA/cm2. In-field property measurement was carried out at temperatures between 10 K and 77 K in magnetic filed up to 6 T in PPMS system. This is the first report, to the best of our knowledge, of TmBCO thin films and coated conductors with TmBCO film as the superconducting layer which have critical current densities at 77 K of 4.5 MA/cm2 and 1 MA/cm2, respectively. The superconducting properties of TmBCO films and the possibility of using TmBCO film as the superconducting layer of the HTS coated conductor, were investigated. [ABSTRACT FROM AUTHOR]

The Ic degradation behaviors of Bi-2223 superconducting tapes under pressurized liquid nitrogen were investigated using a newly developed sample holder which gives a series of bending strains to a sample. Four kinds of commercially available multifilamentary Bi-2223 superconducting tapes were used. At atmospheric pressure, the Ic degradation behavior depended upon the reinforcement adopted, the tapes externally reinforced or densified by over pressure showed better bending strain tolerance than the Ag alloy-sheathed Bi-2223 tapes. But these tapes showed a larger Ic degradation when pressurized to 1 MPa in liquid nitrogen. For all samples, after depressurization to atmospheric pressure from 1 MPa, the Ic was completely recovered to its initial values at atmospheric pressure. When the samples were warmed up to room temperature after being depressurized from 1 MPa, ballooning occurred at some parts of some samples. It was found that the larger degradation of Ic occurred at the regions where significant ballooning occurred. [ABSTRACT FROM AUTHOR]

The endurance evaluation of HTS conductors for practical applications is necessary. The mechanical properties and the critical current, Ic, of multifilamentary Bi-2223 superconducting tapes, externally reinforced with stainless steel foils, subjected to high cycle fatigue loading in the longitudinal direction were investigated at 77 K. The relations between the applied stress amplitude and the fatigue life (S-N curves) were obtained using the externally reinforced Bi-2223 tapes, and its transport property was evaluated with the increase of repeated cycles at different stress amplitudes. The effect of the stress ratio, R, on the Ic degradation behavior under fatigue loading was also examined considering the practical application situation of HTS tapes. Microstructure observation was performed in order to understand the Ic degradation mechanism in fatigued Bi-2223 tapes. [ABSTRACT FROM AUTHOR]

It is important to improve critical current density of silver-sheathed Bi-2223 tapes for practical applications of material. Bi-2223/Ag superconducting wires with various sheath materials were fabricated by stacking, drawing process with different pre-annealing schedules. Two kinds of powders were prepared. One was pre-annealed at 760°C and low oxygen partial pressure, and the other was only calcined state. Before rolling process, round wires were pre-annealed at 760°C and in a low oxygen partial pressure. Bi-2223/Ag conductor was needed softening annealing at low temperature during drawing process because pre-annealed precursor powder brought about decrease in workability. Per-annealing let tetragonal structure of Bi-2212 phase of precursor transform to orthorhombic structure and reduce the fraction of second phases at superconducting wire, which could increase critical current density. However the break- ages occurred at Ag-alloy sheathed long Bi-2223/Ag tapes during rolling after pre-annealing. Several pre-annealing scenarios were introduced to reduce the breakages during rolling process. We could achieve proper pre-annealing conditions for Ag-alloy clad Bi-2223 tapes by the analysis of mechanical properties. We could achieve highest Je of 8800 A/cm² at Bi-2223 tape by two-step pre-annealing. [ABSTRACT FROM AUTHOR]

In this paper, characteristics of a heater-triggered switching system for the charging of Bi-2223 double pancake load with 1.7 mit has been analyzed through the simulations and experiments. Two heaters were used to store the energy in high-T[sub c] superconducting (HTS) load. The timing of the sequential control and the heating current with two heaters are important factors to generate pumping-current. The thermal analysis of the switch considering the heater input and time was carried out. Based on the analysis just mentioned, heater-triggered switch was fabricated. Characteristic analysis was carried out through two modes having different sequential timing controls. Maximum current stored in the IIIS load reached 18 A and the pumping rate was 113 mA/s at that time. [ABSTRACT FROM AUTHOR]

Investigates the design and fabrication of a high critical-temperature superconducting (HTSC) power supply with the bismuth-2223 pancake load. Pumping current of the HTSC with respect to magnet flux change; Use of the superconducting switch for heater-trigger.

Studies the effects of drawing parameters on sausaging and critical current density of Bi-2223/Ag high temperature superconducting wires. Hardness and filling factor; Critical current and microstructure; Drawing die conditions.

Describes the fabrication of a 1.5-kilo-ampere Bi-2223 high temperature superconducting current leads for superconducting magnetic energy storage magnets. Design of HTS lead; Measurement critical current of HTS leads; Electromagnetic analysis; Thermal analysis; Critical current in magnetic field.

Describes the fabrication of Bi-2223 high temperature superconducting magnet with a superconducting switch. Operation of the magnet in persistent mode; Use of a simple circuit model to compute field decay time constants; Finding that Pb-Sn solder joints are unsuitable for persistent mode operation; Persistent current operation of magnet; Fabrication of tape and magnet system.

Studies the critical currents of stacked Bi-2223 superconducting tapes. Critical current density measurements; External magnetic flux density; Critical current density and magnetic field distribution.

Studies the effect of twisting on the microstructural evolution and properties of Bi(Pb)-Sr-Ca-Cu-O superconductor tape, and on the resulting critical current. Reduction of losses for tapes with various geometries; Mechanisms of nucleation, grain growth, grain alignment, and interface chemical reaction for BSCCO superconductor phases.

Reports on the operational characteristics of discrete-sheet type low-critical temperature superconducting (LTS) power supply. Comparison between continuous-sheet type LTS power supply and discrete-sheet type LTS power supply; Maximum pumping-current; LTS power supply concept; Electrical parameters.

Describes a stand-alone solid nitrogen cooled permanent high temperature superconducting magnet system. Shunting of the magnet with a superconducting switch; Use of six double pancakes each wound with BSCCO-2223 silver composite tape and a volume of solid nitrogen; Magnetic and thermal requirements of the system.

Reports on a study of alternating current (AC) loss dependency on joint method in high temperature superconducting tapes. AC loss in BSCCO-2223 silver sheathed tapes; Finding that AC loss depends on amplitude of transport current and on joint resistance; Use of superconducting joint method and resistive joint method.

Cable conductors fabricated by bundling coated conductors to increase the transport current have been developed for large-scale electric applications such as highly magnetic field magnets, large accelerators and fusion reactors. Various types of cable conductors (CORC cables, Roebel cables, TSTC and round wires) have been fabricated using coated conductors; however, these cable conductors do not have a high engineering critical current density (Je) required high performance in large-scale applications. In this study, new high temperature superconducting (HTS) multilayered conductors have been fabricated to increase the critical current and Je of coated conductors as cable conductors. The property of easy exfoliation owing to the weak c-axis strength of coated conductors is used to fabricate multi layered HTS conductors. In order to stack and bond multiple-HTS layers on one substrate (MHOS), a silver diffusion bonding technique using only a silver plated coated conductor is adopted. The MHOS conductor consists of multiple, biaxial-, textured, superconducting layers without any intermediate epitaxial grown buffer layer or solder layer between them. A 1 m long 4-MHOS conductor was successfully fabricated to proposed fabrication process; it exhibited a high critical current (2484 A/12 mm-w) and high engineering critical current density (Je = 0.12 MA cm−2). The critical current of the fabricated MHOS conductor at liquid nitrogen temperature (65–77 K) with a magnetic field ranging from 0 to 6 T increased proportionally with the number of superconducting layers. [ABSTRACT FROM AUTHOR]

Examines the degradation of critical currents in superconducting joints of reacted Bi-2223/Ag multifilamentary tapes. Tape fabrication; Jointing pressure for various jointing samples; Magnetic fields for joint samples.