The Experts below are selected from a list of 273 Experts worldwide ranked by ideXlab platform
Francesco Grilli - One of the best experts on this subject based on the ideXlab platform.
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open source codes for computing the critical current of Superconducting Devices
IEEE Transactions on Applied Superconductivity, 2016Co-Authors: Victor M R Zermeno, Salman Quaiyum, Francesco GrilliAbstract:In order to transport sufficiently high current, high- temperature superconductor (HTS) tapes are assembled in cable structures of different forms. In such cables, the tapes are tightly packed and have a strong electromagnetic interaction. In particular, the generated self-field is quite substantial and can give an important contribution in reducing the maximum current the cable can effectively carry. In order to be able to predict the critical current of said cable structures, a static numerical model has been recently proposed. In this contribution, we present in detail the implementation of such models in different programming environments, including finite-element-based and general numerical analysis programs, both commercial an open- source. A comparison of the accuracy and calculation speed of the different implementations of the model is carried out for the case of a Roebel cable. The model is also used to evaluate the importance of choosing a very accurate description of the angular Jc(B) dependence of the superconductor as input for the material's property. The numerical codes, which are open-source, are made freely available to interested users. Index Terms—Critical current, Superconducting cables, Self- field effects, Numerical simulations, Open source. calculate the critical current of HTS cables and windings, using the Jc(B) dependence of the superconductor as input (6). The method uses a power-law E-J relationship for the superconductor. The strength of the method resides in the introduction of a variable P that allows avoiding the direct solution of the nonlinearE-Jrelationship, hence providing a simpler problem that can be easily solved. Another remarkable feature is that, depending on the application considered (cable, coils, coils made of cables) and the particular experimental setup, different criteria for the definition of the critical current Ic can be used. The method has been successfully tested against experiments for a variety of Superconducting Devices and working conditions. With this contribution we aim to explain in more technical
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open source codes for computing the critical current of Superconducting Devices
arXiv: Superconductivity, 2015Co-Authors: Victor M R Zermeno, Salman Quaiyum, Francesco GrilliAbstract:In order to transport sufficiently high current, high-temperature superconductor (HTS) tapes are assembled in cable structures of different forms. In such cables, the tapes are tightly packed and have a strong electromagnetic interaction. In particular, the generated self-field is quite substantial and can give an important contribution in reducing the maximum current the cable can effectively carry. In order to be able to predict the critical current of said cable structures, a static numerical model has been recently proposed. In this contribution, we present in detail the implementation of such models in different programming environments, including finite-element-based and general numerical analysis programs, both commercial an open-source. A comparison of the accuracy and calculation speed of the different implementations of the model is carried out for the case of a Roebel cable. The model is also used to evaluate the importance of choosing a very accurate description of the angular Jc(B) dependence of the superconductor as input for the material's property. The numerical codes, which are open-source, are made freely available to interested users.
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a self consistent model for estimating the critical current of Superconducting Devices
Superconductor Science and Technology, 2015Co-Authors: Victor M R Zermeno, Frederic Sirois, M Takayasu, M Vojenciak, A Kario, Francesco GrilliAbstract:Nowadays, there is growing interest in using Superconducting wires or tapes for the design and manufacture of Devices such as cables, coils, rotating machinery, transformers, and fault current limiters, among others. Their high current capacity has made them the candidates of choice for manufacturing compact and light cables and coils that can be used in the large-scale power applications described above. However, the performance of these cables and coils is limited by their critical current, which is determined by several factors, including the conductor's material properties and the geometric layout of the device itself. In this work we present a self-consistent model for estimating the critical current of Superconducting Devices. This is of large importance when the operating conditions are such that the self-field produced by the current is a significant fraction of the total field. The model is based on the asymptotic limit when time approaches infinity of Faraday's equation written in terms of the magnetic vector potential. It uses a continuous relationship and takes the angular dependence of the critical current density on the magnetic flux density into account. The proposed model is used to estimate the critical current of Superconducting Devices such as cables, coils, and coils made of transposed cables with very high accuracy. The high computing speed of this model makes it an ideal candidate for design optimization.
Victor M R Zermeno - One of the best experts on this subject based on the ideXlab platform.
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open source codes for computing the critical current of Superconducting Devices
IEEE Transactions on Applied Superconductivity, 2016Co-Authors: Victor M R Zermeno, Salman Quaiyum, Francesco GrilliAbstract:In order to transport sufficiently high current, high- temperature superconductor (HTS) tapes are assembled in cable structures of different forms. In such cables, the tapes are tightly packed and have a strong electromagnetic interaction. In particular, the generated self-field is quite substantial and can give an important contribution in reducing the maximum current the cable can effectively carry. In order to be able to predict the critical current of said cable structures, a static numerical model has been recently proposed. In this contribution, we present in detail the implementation of such models in different programming environments, including finite-element-based and general numerical analysis programs, both commercial an open- source. A comparison of the accuracy and calculation speed of the different implementations of the model is carried out for the case of a Roebel cable. The model is also used to evaluate the importance of choosing a very accurate description of the angular Jc(B) dependence of the superconductor as input for the material's property. The numerical codes, which are open-source, are made freely available to interested users. Index Terms—Critical current, Superconducting cables, Self- field effects, Numerical simulations, Open source. calculate the critical current of HTS cables and windings, using the Jc(B) dependence of the superconductor as input (6). The method uses a power-law E-J relationship for the superconductor. The strength of the method resides in the introduction of a variable P that allows avoiding the direct solution of the nonlinearE-Jrelationship, hence providing a simpler problem that can be easily solved. Another remarkable feature is that, depending on the application considered (cable, coils, coils made of cables) and the particular experimental setup, different criteria for the definition of the critical current Ic can be used. The method has been successfully tested against experiments for a variety of Superconducting Devices and working conditions. With this contribution we aim to explain in more technical
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open source codes for computing the critical current of Superconducting Devices
arXiv: Superconductivity, 2015Co-Authors: Victor M R Zermeno, Salman Quaiyum, Francesco GrilliAbstract:In order to transport sufficiently high current, high-temperature superconductor (HTS) tapes are assembled in cable structures of different forms. In such cables, the tapes are tightly packed and have a strong electromagnetic interaction. In particular, the generated self-field is quite substantial and can give an important contribution in reducing the maximum current the cable can effectively carry. In order to be able to predict the critical current of said cable structures, a static numerical model has been recently proposed. In this contribution, we present in detail the implementation of such models in different programming environments, including finite-element-based and general numerical analysis programs, both commercial an open-source. A comparison of the accuracy and calculation speed of the different implementations of the model is carried out for the case of a Roebel cable. The model is also used to evaluate the importance of choosing a very accurate description of the angular Jc(B) dependence of the superconductor as input for the material's property. The numerical codes, which are open-source, are made freely available to interested users.
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a self consistent model for estimating the critical current of Superconducting Devices
Superconductor Science and Technology, 2015Co-Authors: Victor M R Zermeno, Frederic Sirois, M Takayasu, M Vojenciak, A Kario, Francesco GrilliAbstract:Nowadays, there is growing interest in using Superconducting wires or tapes for the design and manufacture of Devices such as cables, coils, rotating machinery, transformers, and fault current limiters, among others. Their high current capacity has made them the candidates of choice for manufacturing compact and light cables and coils that can be used in the large-scale power applications described above. However, the performance of these cables and coils is limited by their critical current, which is determined by several factors, including the conductor's material properties and the geometric layout of the device itself. In this work we present a self-consistent model for estimating the critical current of Superconducting Devices. This is of large importance when the operating conditions are such that the self-field produced by the current is a significant fraction of the total field. The model is based on the asymptotic limit when time approaches infinity of Faraday's equation written in terms of the magnetic vector potential. It uses a continuous relationship and takes the angular dependence of the critical current density on the magnetic flux density into account. The proposed model is used to estimate the critical current of Superconducting Devices such as cables, coils, and coils made of transposed cables with very high accuracy. The high computing speed of this model makes it an ideal candidate for design optimization.
Jorma Lehtonen - One of the best experts on this subject based on the ideXlab platform.
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Environmental advantages of Superconducting Devices in distributed electricity-generation
Applied Energy, 2007Co-Authors: Teemu Hartikainen, Risto Mikkonen, Jorma LehtonenAbstract:Distributed generation (DG) is emerging as an alternative to a centralized electricity-generation system. The goals of DG include the minimization of the environmental impacts of energy production and introduction of new renewable energy-sources to the distribution network. Superconducting Devices are also proposed for DG because of their high efficiencies as well as smaller size and more stable operation during peak loads. This study concentrates on the environmental benefits of Superconducting machinery by comparing suitable Devices with their competitors in DG-networks. Exploitable Superconducting Devices in DG include Superconducting magnetic energy-storage (SMES), flywheels and cable systems. Life-cycle assessment (LCA) is used as a tool in comparisons of energy-storage Devices suitable for DG: SMESs, flywheels and batteries. In LCA, all material inputs, energy consumptions, wastes, and emissions are assessed over the life-cycle of the product. Finally, a commercialization schedule for HTS-cables is presented and an unconventional concept for a DG-network is suggested for further examination. ?? 2006 Elsevier Ltd. All rights reserved.
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environmental advantages of Superconducting Devices in distributed electricity generation
Applied Energy, 2007Co-Authors: Teemu Hartikainen, Risto Mikkonen, Jorma LehtonenAbstract:Distributed generation (DG) is emerging as an alternative to a centralized electricity-generation system. The goals of DG include the minimization of the environmental impacts of energy production and introduction of new renewable energy-sources to the distribution network. Superconducting Devices are also proposed for DG because of their high efficiencies as well as smaller size and more stable operation during peak loads. This study concentrates on the environmental benefits of Superconducting machinery by comparing suitable Devices with their competitors in DG-networks. Exploitable Superconducting Devices in DG include Superconducting magnetic energy-storage (SMES), flywheels and cable systems. Life-cycle assessment (LCA) is used as a tool in comparisons of energy-storage Devices suitable for DG: SMESs, flywheels and batteries. In LCA, all material inputs, energy consumptions, wastes, and emissions are assessed over the life-cycle of the product. Finally, a commercialization schedule for HTS-cables is presented and an unconventional concept for a DG-network is suggested for further examination.
K. D. Osborn - One of the best experts on this subject based on the ideXlab platform.
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An analysis method for asymmetric resonator transmission applied to Superconducting Devices
Journal of Applied Physics, 2012Co-Authors: M. S. Khalil, M. J.a. Stoutimore, F.c. Wellstood, K. D. OsbornAbstract:We examine the transmission through nonideal microwave resonant circuits. The general analytical resonance line shape is derived for both inductive and capacitive coupling with mismatched input and output transmission impedances, and it is found that for certain non-ideal conditions the line shape is asymmetric. We describe an analysis method for extracting an accurate internal quality factor ($Q_i$), the Diameter Correction Method (DCM), and compare it to the conventional method used for millikelvin resonator measurements, the $\phi$ Rotation Method ($\phi$RM). We analytically find that the $\phi$RM deterministically overestimates $Q_i$ when the asymmetry of the resonance line shape is high, and that this error is eliminated with the DCM. A consistent discrepancy between the two methods is observed when they are used to analyze both simulations from a numerical linear solver and data from asymmetric coplanar Superconducting thin-film resonators.
L Serio - One of the best experts on this subject based on the ideXlab platform.
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a new cryogenic test facility for large Superconducting Devices at cern
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: A Perin, J H Derking, L Serio, L Stewart, V Benda, J Bremer, O PirotteAbstract:To expand CERN testing capability to Superconducting Devices that cannot be installed in existing test facilities because of their size and/or mass, CERN is building a new cryogenic test facility for large and heavy Devices. The first Devices to be tested in the facility will be the S-FRS Superconducting magnets for the FAIR project that is currently under construction at the GSI Research Center in Darmstadt, Germany. The facility will include a renovated cold box with 1.2 kW at 4.5 K equivalent power with its compression system, two independent 15 kW liquid nitrogen precooling and warm-up units, as well as a dedicated cryogenic distribution system providing cooling power to three independent test benches. The article presents the main input parameters and constraints used to define the cryogenic system and its infrastructure. The chosen layout and configuration of the facility is presented and the characteristics of the main components are described.
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cooling strings of Superconducting Devices below 2 k the helium ii bayonet heat exchanger
Advances in cryogenic engineering, 1998Co-Authors: P Lebrun, L Serio, L Tavian, R Van WeelderenAbstract:High-energy particle accelerators and colliders contain long strings of Superconducting Devices — acceleration RF cavities and magnets — operating at high field, which may require cooling in helium II below 2 K. In order to maintain adequate operating conditions, the applied or generated heat loads must be extracted and transported with minimum temperature difference. Conventional cooling schemes based on conductive or convective heat transport in pressurized helium II very soon reach their intrinsic limits of thermal impedance over extended lengths. We present the concept of helium II bayonet heat exchanger, which has been developed at CERN for the magnet cooling scheme of the Large Hadron Collider (LHC), and describe its specific advantages as a slim, quasi-isothermal heat sink. Experimental results obtained on several test set-ups and a prototype magnet string have permitted to validate its performance and sizing rules, for transporting linear heat loads in the W. m”1 range over distances of several tens of meters.
