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Applied Superconductivity, IEEE Transactions on

Issue 6 • Date Dec. 2010

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Displaying Results 1 - 14 of 14
  • [Front cover]

    Publication Year: 2010 , Page(s): C1
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  • IEEE Transactions on Applied Superconductivity publication information

    Publication Year: 2010 , Page(s): C2
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  • Table of contents

    Publication Year: 2010 , Page(s): 2349
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  • Magnetic Force Calculation Between Misaligned Coils for a Superconducting Magnet

    Publication Year: 2010 , Page(s): 2350 - 2353
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB) |  | HTML iconHTML  

    A superconducting magnet system that consists of a cable-in-conduit conductor (CICC) coil and two NbTi solenoid coils is being developed. The superconducting magnet will be capable of generating a central magnetic field of 12 T. The stored energy of the magnet is 2.05 MJ. As a result of possible misalignment between the coil and NbTi coils during installation, there exists a radial or axial force between two types of coils. In this paper, we use the Grover's formulas with filament method to calculate the mutual inductance and its gradient between coils. Based on this method, we apply the mutual inductance gradient method to calculate the radial and axial force between coils. We confirm the validity of this method by comparing it with an exact 3-D semianalytical expression on axial force for coaxial but midplane offset coils. Results obtained by two methods are in excellent agreement. All results obtained on radial and axial forces are introduced. View full abstract»

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  • Finite-Element Analysis of Dump Resistor for Prototype Superconducting Magnet Carrying 3.60 MA-t

    Publication Year: 2010 , Page(s): 2354 - 2359
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1031 KB) |  | HTML iconHTML  

    Stability margin, transient ac responses, and protection of the magnet system in the case of abnormal quench are some of the important design drivers of superconducting magnets for fusion reactors. A prototype magnet has been designed using a cable-in-conduit conductor with a nominal operation current of 30 kA at 12 T and 5 K at the Institute for Plasma Research, Gandhinagar, India. Protection of the magnet system during off-normal scenarios leading to quench makes the operation of the magnet system more challenging. An external dump resistor is required to extract the stored magnetic energy of the magnet in case of quench. Such a dump resistor has been designed for this 3.60 MA-turns current-carrying prototype superconducting magnet. Finite-element thermal, structural, and electromagnetic analyses have been done for validating the dump resistor parameters using commercially available Ansys software. The maximum temperature rise of the dump resistor system is found to be 540 K, considering cool down by natural convection only. In addition, the maximum stress between the parallel plates of the is found to be less than 1.0 GPa, which is in the acceptable range. View full abstract»

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  • Measurement of Electromagnetic and Thermal Stresses on Conduction-Cooled Joints of the SST-1 Spare TF Coil

    Publication Year: 2010 , Page(s): 2360 - 2369
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1623 KB) |  | HTML iconHTML  

    Low-dc-resistance superconducting joints in toroidal- and poloidal-field (TF and PF, respectively) coils of the steady-state superconducting tokamak-1 (SST-1) at the Institute for Plasma Research (IPR) is under testing. The feasibility of conduction-cooled leak-tight joints made between two double pancakes in the winding pack of the TF coil is validated through experiments. The configuration of these conduction-cooled joints is comprised of a prefabricated SS304L oxygen-free high-conductivity copper leak-tight termination, into which the unconduited and soldered portion of the cable-in-conduit-conductor (CICC) is inserted. Once the cable space is inserted inside the prefabricated piece, solder filling is carried out, and the joints are realized by overlapping the mating ends and soldering them together. The supercritical helium flowing through the CICC exits prior to the termination length, and the joints are cooled by conduction. The joints are subjected to I × B-induced and bending-induced stresses during SST-1 operational scenarios. These stresses can lead to leaks in the joint region if they exceed the material strength or the brazing/welding strength. Both the thermal and electromagnetic stresses that developed at the copper-stainless steel prefabricated brazed region are measured on the SST-1 spare TF coil. These stresses are measured using the strain gauges during the cooldown and the charging of the spare TF coil up to its operational current of 10 kA at a conventional 4.5 K and 4 bar of supercritical helium forced flow. The electromagnetic-stress behavior at the time of quench that occurred accidently during the spare TF coil test at an 8 kA transport current was also studied. The signal-conditioning electronics required for this measurement are engineered and tested at the IPR before its implementation to the spare-TF-coil test campaign. The measured thermal and electromagnetic stresses are found to be in good agreement with the simulated finite-el- - ement Ansys results. View full abstract»

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  • Three-Dimensional Micrometer-Scale Modeling of Quenching in High-Aspect-Ratio \hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7 - \delta } Coated Conductor Tapes—Part I: Model Development and Validation

    Publication Year: 2010 , Page(s): 2370 - 2380
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1109 KB) |  | HTML iconHTML  

    YBa2Cu3O7-δ coated conductors have very slow normal-zone propagation velocity, which renders quench detection and protection very difficult. To develop effective quench detection methods, it is paramount to study the underlying behavior that drives quench propagation at the micrometer-scale level. Toward this end, numerical mixed-dimensional models, composed of multiple high-aspect-ratio thin layers, are developed. The high-aspect-ratio modeling issues are tackled by approximating the thin layers either as a 2-D surface or as an analytical contact resistance interior boundary condition, which also acts as a coupling bridge between the 2-D and 3-D behaviors. The tape models take into account the thermal and electrical physics of each layer in actual conductor dimensions and are implemented using commercial finite-element analysis software. In the first part of this two-part paper, the mixed-dimensional models are introduced and then computationally and experimentally validated. Validations are gauged by comparisons in normal-zone propagation velocity and in the time-dependent voltage and temperature profiles. Results show that the mixed-dimensional models can not only effectively address the high-aspect-ratio modeling issues of thin films but also accurately and efficiently reproduce physical quench phenomena in a coated conductor. View full abstract»

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  • Fast Numerical Computation of Current Distribution and AC Losses in Helically Wound Thin Tape Conductors: Single-Layer Coaxial Arrangement

    Publication Year: 2010 , Page(s): 2381 - 2389
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (597 KB) |  | HTML iconHTML  

    In this paper, we introduce a very fast method to compute the current distribution in helically wound thin conductors when one or many of them are arranged in a symmetrical manner to form a single-layer power cable. The method relies on two different approaches to find the magnetic vector potential due to helically wound current sheets. By invoking relevant symmetry arguments associated with the geometry of the problem and neglecting the thickness of the tape conductors, we show that this 3-D problem can be reduced to a computationally small 1-D problem whose domain lies along the half-width of any of the constituting conductor. As a consequence, the proposed method is very efficient in terms of computational time, and it is more accurate than many previous 2-D methods that cannot take into account the twist pitch. Since the nonlinear resistivity of the superconducting material can easily be treated with this method, it can be used to find current and field distributions, as well as ac losses in high-temperature superconductor coils and cables made of coated tapes. To verify the validity of the proposed method, we performed experimental measurements of ac losses in two configurations of solenoid-type cables made of a sample of YBCO-coated conductor tape. Excellent agreement was observed between the experimental data and the simulation results. View full abstract»

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  • On the Superconductivity and Mg Outdiffusion in Vacuum-Synthesized \hbox {MgB}_{2} Samples

    Publication Year: 2010 , Page(s): 2390 - 2396
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB) |  | HTML iconHTML  

    MgB2 samples have been synthesized over a wide temperature range and from the stoichiometric and excess magnesium composition. The role of magnesium overdoping on the superconducting characteristics of MgB2 has been studied, and hence, the correlation between the critical current density, porosity, and density of the MgB2 samples has been established. The excess magnesium in the starting composition expands the synthesis temperature range over which the MgB2 phase can be synthesized and also enhances the superconducting properties in terms of Tc, ΔT, and residual resistivity ratio. The reduced weight loss due to Mg vaporization, and hence the lower porosity in the sample synthesized from the stoichiometric composition and at Ts = 900°C, reflected the higher Jc in the MgB2 sample in this series. Whereas with the excess magnesium in the starting composition, the sample with the highest Jc has been synthesized at a lower synthesis temperature of Ts = 700°C. The correlation between weight loss during heat treatment, sample density, resistivity, and active area fraction has been established for vacuum-synthesized bulk MgB2 samples. View full abstract»

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  • Heat Treatment and Characterization of \hbox {Nb}_{3} \hbox {Sn} Strands for the Model Coil of the 40-T Hybrid Magnet

    Publication Year: 2010 , Page(s): 2397 - 2401
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (544 KB) |  | HTML iconHTML  

    A model coil for the 40-T hybrid magnet is being built at the Chinese High Magnetic Field Laboratory, Chinese Academy of Sciences. /restack-rod-process (RRP) strands adopted for the model coil were heat-treated according to the heat treatment (HT) schedule recommended by the manufacturer, which is Oxford Superconducting Technology. The microstructure of the reacted strand was analyzed. Measurements of the critical current, the residual resistivity ratio and the hysteresis losses were also carried out. The results of critical-characteristic measurements confirmed that the performance of the heat-treated wire was good. All characteristics indicated that the HT of the /RRP strands was successfully completed. View full abstract»

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  • Compact Miniature High-Resolution Thermometer

    Publication Year: 2010 , Page(s): 2402 - 2405
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    We report a compact miniature high-resolution thermometer (CMHRT) based on dilute paramagnetic alloy of PdMn and commercially available Neodymium (NdFeB) magnets. The thermometer utilizes the temperature dependence of magnetic susceptibility of the alloy in an applied magnetic field. The change in susceptibility is measured with a pickup coil connected to a dc-SQUID. Based on this approach, we have developed a self-contained thermometer with sub-nanoKelvin sensitivity with the operating temperature range of 1.6-4 K. Its design, assembly, and performance are described. View full abstract»

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  • 2010 Index IEEE Transactions on Applied Superconductivity Vol. 20

    Publication Year: 2010 , Page(s): 2406 - 2492
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  • IEEE Transactions on Applied Superconductivity upcoming special conference issues

    Publication Year: 2010 , Page(s): C3
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  • IEEE Transactions on Applied Superconductivity Information for authors

    Publication Year: 2010 , 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