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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]

It is environmentally important to recycle the wastewater, since paper factories use a large amount of water and equivalent amount of wastewater is generated. Conventional water treatment facilities like precipitation process need large-scale equipment and wide space to purify the wastewater of paper factory. In case of massive waste water, high gradient magnetic separation (HGMS) parts are more effective to purify it rapidly and to occupy relatively small space, since large voids at filter with HGMS are adopted. In this respect, we prepared two types of superconducting magnets in order to apply HGMS parts for wastewater purification process. We made cryo-cooled Bi-2223 (HTS) superconducting magnet parts with room temperature bore in diameter of 70 mm and 200 mm in height. Also, cryo-cooled Nb-Ti superconducting magnet with room temperature bore in diameter of 100 mm and 600 mm in height was used for magnetic separator. Magnetic filters were designed by the analysis of magnetic field distribution at superconducting magnets. The faster wastewater's flow rate was, the worse the degree of clarity in treated water was. The ability of wastewater treatment in the case of magnetic separation used with 10 µm of magnetite particles was better than that in the case of 5 µm of magnetite particles. [ABSTRACT FROM AUTHOR]

The Hall probe measurement system was used to measure the critical current distribution of superconducting coated conductor. The system consists of reel to reel moving apparatus, 7 array Hall probe, a rotary encoder and permanent magnet. The magnetic field profile across the width of superconducting coated conductor using Bean's critical state model was calculated. The effect of various parameters of the formulas on the magnetic field distribution and the effect of shape and size of artificial defects, which were formed on the surface of SmBa2Cu3O7-d(SmBCO) coated conductor using laser marking system, on the Hall probe magnetic field signal of the Hall probe measurement system was investigated. [ABSTRACT FROM AUTHOR]

Long-length Sm1+xBa2-xCu3O7-y (SmBCO) coated conductor was fabricated using ion beam assisted deposition(IBAD)-MgO template (LaMnO3/IBAD - MgO/Y2O3/Al2O3/Hastelloy) by the reactive co-evaporation method for electric power applications. SmBCO superconducting layers with thicknesses from 1 to 3 µm were deposited to investigate the effect of SmBCO thickness on the in-plane texture, surface morphology and superconducting properties. In this study, the optimal deposition conditions were examined to make thick SmBCO coated conductor without degradation of critical current density. The oxygen partial pressure and temperature were controlled in the range of 1 ~ 20 mTorr and 600 ~ 800°C, respectively. SmBCO/IBAD-MgO coated conductors showed high critical current densities over 2.0 MA/cm² with small amount of degradation by increasing the thickness of superconducting layer up to 3 µm. The critical current of 637.5 A/cm-w (JC = 2.12 MA/cm²) at 77 K in self-field was obtained in 3 µm-thick and 1 m long coated conductor. This is the highest critical current reported so far of the coated conductor with SmBCO superconducting layer deposited by co-evaporation. [ABSTRACT FROM AUTHOR]

It is important to recycle industrial wastewater in the aspect of energy saving and minimizing the environment damage. Steel manufacture factories make an effort to purify and recycle wastewater from the manufacturing processes. A steel manufactory inKorea, POSCO (POhang iron and Steel COmpany) has also concerned about the treatment of wastewater for long time. The coolant of hot roller at steel making factory includes suspended solid (SS) like steel fines, iron oxide and emulsified oil. A laboratory-scale conduction cooled high temperature superconducting (HTS) magnet was used for high gradient magnetic separation (HGMS) systems. It consists of eight double-pancake sub-coils, two HTS current leads, a GMcryo-cooler and a cryostat without a radiation shield vessel. Sub coils were wound with 1 G HTS tapes of Sumitomo Electric Industries by wet-winding method. A Cryo-cooled high temperature superconducting magnet system with 70 mm room temperature bore and 250 mm of height was prepared. This magnet was used for batch type HGMS system. Superconducting HGMS system that had a purpose to purify the wastewater was assembled. Various magnetic seeding reactions were investigated to increase the reactivity of coagulation. [ABSTRACT FROM AUTHOR]

Considering the expansion of application field of coated conductor (CC) tapes, it is preferred to adopt IBAD substrate which has high yield strength to resolve the strength problem. The electro-mechanical characteristics of the CC tapes will be influenced by the superconductor type and the deposition process adopted during manufacturing. In this study, the Ic degradation behavior of jointed IBAD processed CC tapes under uniaxial tension has been investigated. The Ic degradation behavior of the jointed CC tapes under uniaxial tension has also been compared with those in single tapes. Differently processed YBCO and SmBCO CC tapes with IBAD substrate have been used as samples. The CC tapes jointed by mechanical controlled method were subjected to uniaxial loading. Joint resistances and critical current of lap-jointed specimens have been derived from the I - V curves obtained at each tensile load at 77 K under self-field. In the case of YBCO CC tapes, lap-jointed tape showed a comparable irreversible strain limit with the single tape. [ABSTRACT FROM AUTHOR]

The important merit of Bi-2212/Ag high Tc superconducting wire is to apply cable as round wire geometry. Bi-2212/Ag wires were fabricated in order to develop Rutherford cable for SMES near the future. Various Ag ratio and various numbers of filaments for PIT (Powder-In-Tube) process were applied to investigate the workability during drawing and to improve critical current property of the wires. Rutherford cabling machine for B-2212/Ag strands was designed and manufactured. We designed and manufactured Rutherford cabling machine with 32 bobbins which had 2 km length of wire. This machine was constituted with Turks head, caterpillar tread and take-up facility. In order to obtain uniform working conditions without defects, Turks head's rolling system and Ag ratio of Bi-2212/Ag strands were modified. We tried to fabricate Rutherford cables with 20 and 30 Bi-2212 strands. Proper working conditions for without breakage strand in cable were investigated. We made successfully Bi-2212 Rutherford cable. The critical current of Bi-2212 Rutherford cable with 30 strands showed 420 A at 64 K and 4008 A at 4.2 K. The critical current of Bi-2212/Ag wire with 847 filaments was 398 A at 4.2 K and self field. [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]

The evaluation of reliability of HTS tapes is necessary for practical applications such as magnet, power cables, motors, SMES and HTS coils. The bending strain effect on the critical current, Ic, in multifilamentary Bi-2223 HTS tapes have been investigated. Single and double layered tapes (for high current capacity) were subjected to thermal and pressurization cycles at pressurized liquid nitrogen (LN2) up to 1 MPa. After the pressurization test, the subsequent occurrence of damage like ballooning due to the diffusion and expansion of LN2 into the tapes were investigated and compared. The Bi-2223 tapes showed different Ic, degradation behavior depending upon the geometry and ratio of reinforcement to superconductor adopted. [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 a YBCO coated conductor (CC) tape (RABiTS/MOD) was investigated using a sample holder which gives torsional angles to HTS tapes. The Ic degradation in YBCO CC tape under torsional strains occurred gradually which is a characteristic feature under torsion. Uniform torsional deformation was induced in the YBCO CC tape evident from the consistent Ic degradation behavior at each subsection along the longitudinal direction of the tape. Similar with the tension case, the reversible behavior of Ic under torsional loading was found. The irreversible strain, ϵirr .t., was ∼.6%. The critical strain defined by the 95% Ic retention criterion was 1.4% which was located within. the irreversible limit. The n.value—θ behavior in the YBCO CC tape was similar to the Ic/Ic0—θ behavior. [ABSTRACT FROM AUTHOR]

The important merit of Bi-2212/Ag high Tc superconducting wire is to apply cable as round wire geometry. Bi-2212/Ag wires were fabricated in order to develop Rutherford cable for SMES near the future. Various Ag ratio and various numbers of filaments for PIT (Powder-In-Tube) process were applied to investigate the workability during drawing and to improve critical current property of the wires. In order to find proper working process, we investigated the variation of drawing stress during working. Post-annealing of Bi-2212/Ag wires at various atmospheres was carried out after main heat-treatment in order to increase critical current density. The results of post-annealing in nitrogen were better than that of post-annealing in oxygen. Jc of Bi-2212/Ag wire was increased as increased maximum temperature, Tm, for partial melting until 890°C, and highest Jc was over than 2000 A/mm2. The shape of grain was observed by SEM to investigate Bi-2212 phase formation in filaments. The critical current density increased in proportion to the increase of Bi-2212/Ag wire's filaments number. [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]

The Influence of the bending strain on the critical current (I[sub c]) in Ag alloy/Bi-2223 superconducting tapes was investigated at 77 K. The strain effect on I[sub c] degradation in the different bending modes is discussed in terms of sample geometry and n-value. The I[sub c] degradation behavior with bending occurring across the tape's width direction called 'hard bending' is discussed in particular, and compared with results under conventional bending tests known as 'easy bending'. It was found that I[sub c] degraded with increases in the bending strain. In the case of hard bending, greater degradation in I[sub c] occurred than under easy bending. This might be a result of the difference in the filaments cross-section of the tape and the generation of a new type of damage, such as local buckling, expected during hard bending. The n-value also decreased as the bending strain increased and its behavior was similar to the I[sub c]-bending strain relationship. [ABSTRACT FROM AUTHOR]

We joined 19-multifilamentary Bi-2223 superconductor tapes and fabricated double-pancake coils by using resistive- and superconducting-joint methods. The critical current ratio (CCR) of the jointed tape and the decay characteristics, joint resistance, and n-value of the pancake coils were evaluated. The joint resistance of the coils was characterized by the field decay technique. It was observed that the CCR was higher in the joined tape made by the resistive-joint method, compared to that by the superconducting-joint method. On the other hand, joint resistance was measured to be 4 orders of magnitude smaller in the superconducting-joint coil; approximately 40% of critical current was retained in the persistent current mode and the joint resistance was 0.18 nΩ. Better and longer retention of the magnetic field in the superconducting-joint coil is believed to be due to the direct connection between the superconducting cores. [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 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 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.

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.

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.

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.

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.

It is needed several large reservoirs and long operating time in order to remove suspended solid (SS) like steel fines and iron oxide at steel making factory. If removing rate of SS in coolant of hot rolling process can be increased, the productivity of working process can be increased and the area of reservoir can be reduced. We investigated the formation ability of magnetic flock which mixed with inorganic materials and polymer coagulants. Iron hydroxide and electrolytic dissociation were used for pretreatment. We assembled reciprocal superconducting HGMS system that had a purpose to remove SS of coolant at steel factory. The wire of filter was used stainless steel 420. Maximum coagulation formation rate of SS was 98%. Removing ratio of Fe3O4 fine particles in artificial wastewater showed over than 99% after four times of repetition of magnetic separation. [ABSTRACT FROM AUTHOR]

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.