Thermal design of superconducting cryogenic rotor: Solutions to conduction cooling challenges

This paper describes the design and testing of the first cryogenic rotor based on conductively cooled superconducting stacked tape pseudo bulks used in a rotating machine with various magnetisation methods. The rotor design demanded a number of unusual features and constraints that required novel, innovative solutions that may be applicable in other designs. The aim of this work is not to create a complete design manual, rather, to suggest some ideas that could be useful to others who are looking to solve similar problems. The outline of the proposed design is followed by a detailed description of the key systems and their interactions. Several innovative design characteristics are discussed, including calculation of liquid cryogenic cooling. Finally, experimental thermal results indicate that the design calculations are reliable and provide reaffirmation of the overall success of the design

Barriers to and enablers of sustainable practices: insights from ethnic minority migrants

Migration from the Global South to Global North is a major feature of contemporary population movements, and provides a lived experiment of the implications of moving from less resource-intensive modes of living towards more resource-intensive ones. Pre-migration practices come together in complex ways post-migration with established norms and infrastructures in destination countries. Here we examine the barriers to and enablers of sustainable practices, synthesising in-depth research from nine different studies in south-eastern Australia in relation to household water use, food growing and transport. The total sample includes 323 migrants from 33 countries. The main barriers include infrastructure and broader patterns of work and society. The main enablers are cultural norms of frugality and preferences for public transport. Barriers and enablers interact in diverse ways. We show that migrants are important contributors to inadvertent sustainabilities, but their contributions may be weakened by infrastructural, structural and cultural barriers. Addressing the diverse capacities of migrants would enhance system change for everyone

Direct measurement of the vortex migration caused by traveling magnetic wave

We studied the magnetisation of a 2 in. diameter YBCO thin film in the presence of traveling magnetic waves with six hall sensors. Simulation based on finite element method was conducted to reproduce the process of magnetisation. We discovered that the magnetisation of YBCO thin film based on traveling waves does not follow the constant current density assumption as used in the standing wave condition. We have shown that the traveling wave is more efficient in transporting the flux into the YBCO thin film, which suggests the potential of a flux injection device for high temperature superconducting coils

Study of the penetration of a 2 inches diameter YBCO thin film with the travelling magnetic wave

In this paper, we provide a thorough study on the penetration of a 2-in diameter YBCO thin film with the help of a travelling magnetic wave. The travelling magnetic wave is generated by a circular-type magnetic flux pump device, which is comprises of three phase windings and dc coils. We used one single hall sensor to measure the magnetic flux density 1.5 mm axially above the center of the sample. The results show that the presence of the YBCO sample had amplified the magnetic field by two times of the travelling wave in the center. After placing the hall sensor at r = 10 mm, we found that the magnetic field had been decreased by the presence of the sample. In order to clarify whether the flux had been bended or if there is an actual flux migration, we used a six-hall sensor array to measure the trapped field after applying the travelling wave. The measurement shows that the full penetration happens after the output voltage of the inverter Vac ≥ 40 V (maximum field 4.4 mT). The results indicate that, compared with the standing wave, the travelling wave is more efficient to help vortices penetrate into the sample center. Moreover, in practical operation of a high-temperature superconducting (HTS) flux pump, an HTS film with large width is not recommended