The mechanical properties of Y-Ba-Cu-O and Gd-Ba-Cu-O/Ag bulk superconductor magnets

Single-grain RE-Ba-Cu-O bulk high temperature superconductors [or (RE)BCO, where RE = rare earth element or yttrium] have demonstrated significant potential for practical applications due to their ability to trap magnetic fields in excess of 17 T, which is an order of magnitude greater than what can be achieved with conventional iron-based permanent magnets. One of the major obstacles to the use of (RE)BCO trapped field magnets is their poor mechanical properties, as bulk samples typically contain a large number of defects, such as pores and micro-cracks. Furthermore, significant electromagnetic stresses develop in bulk superconductors during magnetisation as a result of the Lorentz force, leading frequently to sample failure above around 10 T. Therefore, it is clear that the mechanical properties of bulk (RE)BCO need to be studied comprehensively and improved upon to realise the full potential of this technologically important material. This study first investigated the mechanical strength of YBCO single grains at room temperature by utilising three-point bend and Brazilian tests. This was followed by measurement of the mechanical deformation of GdBCO/Ag single grains in situ, i.e. during high-field magnetisation, to determine the strains and stresses experienced by the samples as a trapped field was established inside them at 64 K. Two techniques for improving the mechanical reliability of (RE)BCO bulk superconductors were subsequently developed. Firstly, samples of YBCO were melt-processed with artificial holes to reduce the defect population and to improve the intrinsic strength of the resultant single grains. As a result, the YBCO sample with artificial holes was able to survive significantly higher magnetisation fields and achieved a surface trapped field of 8.8 T at 30 K without any external reinforcement, which was not possible with the standard YBCO sample. Secondly, a composite structure was proposed, which involved reinforcing GdBCO/Ag single grains with stainless-steel sheets and shrink-fit stainless-steel rings. This preparation technique is also expected to improve the thermal stability of the overall structure. The first composite stack achieved 16.8 T and 17.6 T at 26 K and 22.5 K, respectively, in sequential magnetisation cycles, demonstrating the effectiveness of this reinforcement approach

高温超電導バルク銅酸化物の磁束ピン止め制御に関する研究

東京海洋大学博士学位論文 平成25年度(2013) 応用環境システム学課程博士 甲第311号指導教員: 和泉充全文公表年月日: 2014-07-04東京海洋大学201

International Symposium on Magnetic Suspension Technology, Part 1

The goal of the symposium was to examine the state of technology of all areas of magnetic suspension and to review related recent developments in sensors and controls approaches, superconducting magnet technology, and design/implementation practices. The symposium included 17 technical sessions in which 55 papers were presented. The technical session covered the areas of bearings, sensors and controls, microgravity and vibration isolation, superconductivity, manufacturing applications, wind tunnel magnetic suspension systems, magnetically levitated trains (MAGLEV), space applications, and large gap magnetic suspension systems

Tailoring Superconductor and SOFC Structures for Power Applications

High temperature superconductors (HTS) and solid oxide fuel cells (SOFCs) both offer the possibility for dramatic improvements in efficiency in power applications such as generation, transmission and use of electrical energy. However, production costs and energy losses prohibit widespread adoption of these technologies. This thesis investigates low-cost methods to tailor the structures of HTS wires and SOFCs to reduce these energy losses. Section I focusses on methods to produce filamentary HTS coated conductors that show reduced AC losses. This includes spark-discharge striation to pattern existing HTS tapes and inkjet printing of different filamentary architectures. The printed structures are directly deposited filaments and ‘inverse’ printed tracks where an initially deposited barrier material separates superconducting regions. Furthermore, the concept and first stages of a more complex ‘Rutherford’ cable architecture are presented. Additionally, Section I investigates how waste material produced during the manufacture of an alternative low-AC loss cable design, the Roebel cable, can be used to make trapped field magnets that produce a uniform magnetic field profile over a large area. This trapped field magnet work is extended to study self-supporting soldered stacks of HTS tape that demonstrate unprecedented magnetic field uniformity. Section II looks at how nanostructuring porous SOFC electrodes via solution infiltration of precursors can improve long-term stability and low temperature performance. Inkjet printing is utilised as a scalable, low-cost technique to infiltrate lab-scale and commercial samples. Anode infiltration via inkjet printing is demonstrated and methods to increase nanoparticle loading beyond ~1 wt% are presented. Symmetric cells with infiltrated cathodes are shown to have improved performance and stability during high temperature aging. Additionally, the sequence of solution infiltration is found to be important for samples dual-infiltrated with two different nanoparticle precursors.EPSR

Novel Lorentz Force Velocimetry system based on bulk high-temperature superconductors

Die Lorentzkraftanometrie (LKA) ist eine Technik zur Messung der Geschwindigkeit von elektrisch leitfähigen Flüssigkeiten. Sie ist eine nicht-invasive Messtechnik, die besonders vorteilhaft für heiße, opake und aggressive Elektrolyte ist. Die LKA wurde für Salzwasser als Modellelektrolyt erfolgreich mit Dauermagnetanordnungen (DM) ohne magnetischen Rückschluss, aber mit gezielter Flussführung (Halbach-Array) und hochpräzisen Kraftmesssytemen (KMS) auf Basis der interferometrischen Messung der Auslenkung des Magnetsystems und der elektromagnetischen Kompensation der Auslenkung demonstriert. Um die LKA für schwach leitfähige Elektrolyte zu erweitern, ist eine Magnetfelderzeugung von > 1 T erforderlich. Ein Hochtemperatursupraleiter-Bulk (Bulk-HTS) kann ein Magnetfeld von mehreren Tesla erzeugen und somit die LKA-Leistung deutlich verbessern und die bisher genutzten DM ersetzen. Diese Arbeit zielt deshalb darauf ab, Bulk-HTS's in der LKA unter Berücksichtigung der kritischen Verbindungen zwischen der Funktionalität von Bulk-HTS's und dem KMS einzusetzen und ein LKA-System mit Bulk-HTS's zu entwerfen, herzustellen und zu testen. Die Ergebnisse wurden für die Entwicklung eines neuartigen LKA-System auf Basis eines Bulk-HTS als Magnetfeldquelle und einer Torsionswaage als Kraftmesssystem genutzt. Dieses System - Superconducting High-precision Lorentz Force Measurement System (Super-LOFOS) - wurde dann erfolgreich aufgebaut und getestet. Bei Kühlung mit flüssigem Stickstoff bzw. Helium werden auf der Stirnfläche des Super-LOFOS magnetische Flußdichten von B_T = 100 mT bzw. B_T = 1,2 T erzeugt. Damit erweitert die vorliegende Arbeit die Einsetzbarkeit der LKA für gering elektrisch leitende und langsam strömende Fluide auf (σ · u) = 1-10) S s⁻¹, sowie macht hochpräzise Kraftmessungen bis 1 nN unter kryogenen Bedingungen möglich. Darüber hinaus stellt das entwickelte Messsystem Super-LOFOS einen tragbaren Magnetfeldgenerator dar, der für NMR- und MRT-Technologien, Drug Targeting, und magnetische Trennungsverfahren einsetzbar ist.Lorentz Force Velocimentry (LFV) is a technique to measure the velocity of electrically conducting fluids. The advantage of LFV is that this non-invasive measurement method is particularly well suited for use on hot and opaque liquids as well as aggressive electrolytes. LFV for saline water - the model electrolyte - was successfully demonstrated using permanent magnet (PM) configurations without an iron yoke magnetic flux guide, but with targeted magnetic flux guidance (Halbach-array) and a high-precision force measurement system (FMS) based on interferometric measurements of magnet system (MS) deflection and electromagnetic force compensation balance. To extend the LFV for weakly conductive electrolytes, it is required to generate a magnetic field over 1 T. A bulk high-temperature superconsuctors (HTSs) can generate the magnetic field of several teslas and therefore can significantly enhance LFV performance, replacing previously used PM. This thesis aims to integrate the bulk HTS into the LFV considering the critical links between the functionality of bulk HTS and the FMS with the end goal to design, manufacture, and test a novel LFV system using bulk HTS. The obtained results were used to develop a novel LFV system using bulk HTS as magnetic field generator and a torsion balance as FMS. This LFV system - Superconducting High-precision Lorentz Force Measurement System (Super-LOFOS) - was then successfully designed, manufactured, and tested. Using nitrogen and helium cryogenic liquids, the magnetic flux density of B_T = 100 mT and B_T = 1.2 T were generated at the Super-LOFOS front surface, respectively. This thesis also extends the LFV applicability for weakly-conducting and slow-flowing electrolytes (σ · u) = (1-10) S s⁻¹ as well as enabling high-precision force measurements up to 1 nN under cryogenic temperatures. Furthermore, the developed Super-LOFOS provides a portable magnetic field generator, which can be used for NMR and MRI technologies, magnetic separation, and drug targeting applications

Energy Technology Division research summary 2004.

The Energy Technology (ET) Division provides materials and engineering technology support to a wide range of programs important to the US Department of Energy (DOE). The Division's capabilities are generally applied to technical issues associated with energy systems, biomedical engineering, transportation, and homeland security. Research related to the operational safety of commercial light water nuclear reactors (LWRs) for the US Nuclear Regulatory Commission (NRC) remains another significant area of interest for the Division. The pie chart below summarizes the ET sources of funding for FY 2004

Nuclear Fusion Programme: Annual Report of the Association Karlsruhe Institute of Technology/EURATOM ; January 2011 - December 2011 (KIT Scientific Reports ; 7621)

The Karlsruhe Institute of Technology (KIT) is working in the framework of the European Fusion Programme on key technologies in the areas of superconducting magnets, microwave heating systems (Electron-Cyclotron-Resonance-Heating, ECRH), the deuterium-tritium fuel cycle, He-cooled breeding blankets, a He-cooled divertor and structural materials, as well as refractory metals for high heat flux applications including a major participation in the preparation of the international IFMIF project