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Applied Superconductivity, IEEE Transactions on

Issue 4 • Date Aug. 2011

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Displaying Results 1 - 17 of 17
  • [Front cover]

    Page(s): C1
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  • IEEE Transactions on Applied Superconductivity publication information

    Page(s): C2
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  • Table of contents

    Page(s): 3433
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  • Influence of Speed Variation of a Transverse Magnetic Field on a Magnetization of HTS Cylinder

    Page(s): 3434 - 3441
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB) |  | HTML iconHTML  

    In this paper, we numerically study the influence of the speed variation of a magnetic source on the distribution of current density, magnetization, and dissipated energy of a high-temperature superconducting cylinder described by a Jn power law. The results presented come from the resolution of a nonlinear diffusion problem of electric field by a mixed finite-element finite-volume discretization method. This method is robust, stable, and converges for large values of n. The calculations carried out for n, varying from 1 to 200, show that when the external magnetic field quickly varies from 0 to its maximal value, the maximum values of penetration, the magnetization, and the energy dissipation are obtained when the switching of magnetic field occurs. For a periodic magnetic field, we note that any change of the period results in variation of the magnetization and the dissipated energy. View full abstract»

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  • Analytical Model for the Extraction of Flaw-Induced Current Interactions for SQUID NDE

    Page(s): 3442 - 3446
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB) |  | HTML iconHTML  

    Incorporating an analytical approach to simulate the interaction of a series of long cracks and the induced current of a double-D excitation coil, we have developed a model-based method to do precise detection of the positions of the cracks in a metallic structure by using eddy-current superconducting quantum interference device (SQUID) nondestructive evaluation (NDE) measurements. Conventionally, the structure of the defects is found by iteratively solving a numerical forward problem, which is usually based on finite-element, boundary-element, or volume-integral method. This, however, incurs a heavy numerical burden, as every time the forward problem is to be solved, a rigorous numerical model should be inevitably employed to extract the complex distribution pattern of the induced current encountering defects of the structure. In this paper, an analytical approach is used for the modeling of the interaction of the induced current and a series of cracks in the sample. It duly considers the distribution of the induced current in the flawed samples, does not call for extremely high computational resource, and thus permits efficient NDE as the forward problem can be solved within a reasonable time. Here, a high-Tc first-order radio-frequency SQUID gradiometer is employed as the magnetic sensor of the NDE system to scan the samples with different cracks. The accuracy of the proposed algorithm is verified by having the extracted shape of the defects obtained by applying the proposed algorithm on the SQUID NDE measurements against the actual cracks. View full abstract»

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  • Characterization of \hbox {Nb}_{3}\hbox {Sn} Strands for a 40-T Hybrid Magnetic Model Coil

    Page(s): 3447 - 3451
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB) |  | HTML iconHTML  

    A 40-T hybrid magnet under construction at the High Magnetic Field Laboratory of the Chinese Academy of Sciences will use cable-in-conduit conductors for its superconducting outsert. The design necessitates the use of high current density (Jc) Nb3Sn strands (Jc ≥ 2100 A/mm2 at 12 T/4.2 K). The high Jc restacked-rod-processed Nb3Sn strand from Oxford Instruments Superconductor Technology was selected as one of the candidate strands. A series of tests was carried out to qualify the strand performance. Tests mainly included magnetization and critical current measurements as a function of axial strain, magnetic fields, and temperature. The test results are presented and discussed. View full abstract»

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  • Analysis of Energy Dissipation in Resistive Superconducting Fault-Current Limiters for Optimal Power System Performance

    Page(s): 3452 - 3457
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (396 KB) |  | HTML iconHTML  

    Fault levels in electrical distribution systems are rising due to the increasing presence of distributed generation, and this rising trend is expected to continue in the future. Superconducting fault-current limiters (SFCLs) are a promising solution to this problem. This paper describes the factors that govern the selection of optimal SFCL resistance. The total energy dissipated in an SFCL during a fault is particularly important for estimating the recovery time of the SFCL; the recovery time affects the design, planning, and operation of electrical systems using SFCLs to manage fault levels. Generic equations for energy dissipation are established in terms of fault duration, SFCL resistance, source impedance, source voltage, and fault inception angles. Furthermore, using an analysis that is independent of superconductor material, it is shown that the minimum required volume of superconductors linearly varies with SFCL resistance but, for a given level of fault-current limitation and power rating, is independent of system voltage and superconductor resistivity. Hence, there is a compromise between a shorter recovery time, which is desirable, and the cost of the volume of superconducting material needed for the resistance required to achieve the shorter recovery time. View full abstract»

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  • Flux-Based Modeling of Inductive Shield-Type High-Temperature Superconducting Fault Current Limiter for Power Networks

    Page(s): 3458 - 3464
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (542 KB) |  | HTML iconHTML  

    Distributed power generation and the ever-growing load demand have caused fault current levels to exceed the nominal rating of the power system devices, and fault current limiters are more needed. Superconducting fault current limiter (SFCL) forms an important category of current limiters. In this paper, a novel flux-based model for the inductive shield-type high-temperature SFCL is developed based on the Bean model. This model is employed to simulate the SFCL performance in a sample circuit. Utilizing the model, the signal characterization of the limited current is determined. A prototype laboratory scale SFCL has been fabricated with superconducting rings. Yttrium barium copper oxide powders have been used for superconducting ring production. The critical current density of fabricated rings has been measured with an innovative method based on application of a magnet device. The fabricated SFCL has been tested in a circuit by applying different types of faults. The related experimental results are recorded and compared with the model results. The results obtained based on the modeling shows full compatibility with the experimental results. View full abstract»

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  • Structural Design and Analysis of the Model Coil for the Hybrid Magnet Superconducting Outsert

    Page(s): 3465 - 3469
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (739 KB) |  | HTML iconHTML  

    A model coil developed at the High Magnetic Field Laboratory, Chinese Academy of Sciences, will be wound with a Nb3Sn cable-in-conduit conductor (CICC). In this paper, we first introduce the model coil structure and its design requirements and then explicate the important components of the model coil structure, such as the preload structure, joint, cooling circuit, etc. Stress analyses of the preload structure, lead-in and lead-out CICC, joint, transitive CICC, and some supporting structures are performed, and the results are compared with the International Thermonuclear Experimental Reactor metallic and composite structural component design criteria. View full abstract»

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  • Analysis of Magnetic-Supported Suspension Torque Acting on Superconducting Sphere Rotor

    Page(s): 3470 - 3474
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    Based on the Meissner effect, a superconducting sphere is suspended in the vacuum housing. Due to the asphericity of the sphere, the torque is generated when the magnetic-supported suspension forces act on the spinning superconducting sphere. An analytical model is presented to calculate the magnetic-supported suspension torque. The torque is calculated with regard to ten superconducting bearing coils located around the sphere, and a case study is given to discuss the disturbance torque. View full abstract»

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  • Inductively Coupled Josephson Phase Amplification and Its Application as Subterahertz-Wave Direction Sensor

    Page(s): 3475 - 3478
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (270 KB) |  | HTML iconHTML  

    Theoretical and simulation research has been conducted on the inductively coupled Josephson junction phase amplification. Based on theoretical analysis, we give its dynamic equations, which coincide with that of the phase-amplifying model of a parasitoid fly's aural structure. By a numerical method, we study its dynamic behaviors at subterahertz. The results illuminate that the Josephson junction pair can amplify very weak phase delay to detectable magnitude. In addition, the influences of the junction parameter have been investigated, and this unique dynamic behavior could be used in precise subterahertz-wave direction detection. View full abstract»

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  • Induction Heating of Aluminum Billets With Linear Motion in a Strong DC Magnetic Field: Magnetothermal Analysis in Two-Dimensional

    Page(s): 3479 - 3487
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (701 KB) |  | HTML iconHTML  

    This paper presents a new structure of an induction heater for aluminum billets. The device consists in using a strong direct-current magnetic field created by a superconducting inductor in which the conducting billet is actuated by a linear motion at a constant velocity. The analysis, which is based on the analytical model for the magnetic field in the billet, has been developed, and then, the eddy currents and the induced heating power have been evaluated. The analytical results are compared with those issued from the finite-element software (COMSOL). The magnetothermal analysis shows that the temperature profile in the billet is homogenous. View full abstract»

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  • Hydrostatic Pressure Effect on the Critical Current Density of First-Generation Bi-2223 Superconducting Wire

    Page(s): 3488 - 3490
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB) |  | HTML iconHTML  

    A method to transport up to 180 A of current into the sample space of a pressure cell without causing thermal instabilities at 77 K was developed in order to study the critical current Ic of samples of first-generation Bi-2223 superconducting wire at different hydrostatic pressures. Ic was found to linearly decrease with increasing application of external pressure and was found to be irreversible upon release of pressure. The n-value of the voltage-current curves at different pressure was also found to systematically decrease. The decrease in Ic and the irreversibility effect is attributed to the deformation of the filamentary walls of the wire. View full abstract»

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    Page(s): 3491
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    Page(s): 3492
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  • IEEE Transactions on Applied Superconductivity upcoming special conference issues

    Page(s): C3
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  • IEEE Transactions on Applied Superconductivity Information for authors

    Page(s): C4
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Aims & Scope

IEEE Transactions on Applied Superconductivity contains articles on the applications of superconductivity and other relevant technology.

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Meet Our Editors

Editor-in-Chief
Britton L. T. Plourde
Syracuse University
bplourde@syr.edu
http://www.phy.syr.edu/~bplourde