Alignment of Carbon Nanotube Additives for Improved Performance of Magnesium Diboride Superconductors

The rapid progress on MgB2 superconductor since its discovery[1] has made this material a strong competitor to low and high temperature superconductors (HTS) for applications with a great potential to catch the niche market such as in magnetic resonant imaging (MRI). Thanks to the lack of weak links and the two-gap superconductivity of MgB2 [2,3] a number of additives have been successfully used to enhance the critical current density, Jc and the upper critical field, Hc2.[4-12] Carbon nanotubes (CNTs) have unusually electrical, mechanical and thermal properties[13-16] and hence is an ideal component to fabricate composites for improving their performance. To take advantages of the extraordinary properties of CNTs it is important to align CNTs in the composites. Here we report a method of alignment of CNTs in the CNT/MgB2 superconductor composite wires through a readily scalable drawing technique. The aligned CNT doped MgB2 wires show an enhancement in magnetic Jc(H) by more than an order of magnitude in high magnetic fields, compared to the undoped ones. The CNTs have also significantly enhanced the heat transfer and dissipation. CNTs have been used mainly in structural materials, but here the advantage of their use in functional composites is shown and this has wider ramifications for other functional materials.Comment: 11 pages, 3 figures. to be published in Advanced Material

Stressors and coping strategies of migrant workers diagnosed with COVID-19 in Singapore: a qualitative study

Introduction The health, psychological and socioeconomic vulnerabilities of low-wage migrant workers have been magnified in the COVID-19 pandemic, especially in high-income receiving countries such as Singapore. We aimed to understand migrant worker concerns and coping strategies during the COVID-19 pandemic to address these during the crisis and inform on comprehensive support needed after the crisis.Methods In-depth semi-structured interviews were carried out with migrant workers diagnosed with COVID-19. The participants were recruited from a COVID-19 mass quarantine facility in Singapore through a purposive sampling approach. Interviews were transcribed verbatim and thematic analysis performed to derive themes in their collective experience during the crisis.Results Three theme categories were derived from 27 interviews: migrant worker concerns during COVID-19, coping during COVID-19 and priorities after COVID-19. Major stressors in the crisis included the inability to continue providing for their families when work is disrupted, their susceptibility to infection in crowded dormitories, the shock of receiving the COVID-19 diagnosis while asymptomatic, as well as the isolating conditions of the quarantine environment. The workers coped by keeping in contact with their families, accessing healthcare, keeping updated with the news and continuing to practise their faith and religion. They looked forward to a return to normalcy after the crisis with keeping healthy and having access to healthcare as new priorities.Conclusion We identified coping strategies employed by the workers in quarantine, many of which were made possible through the considered design of care and service delivery in mass quarantine facilities in Singapore. These can be adopted in the set-up of other mass quarantine facilities around the world to support the health and mental well-being of those quarantined. Our findings highlight the importance of targeted policy intervention for migrant workers, in areas such as housing and working environments, equitable access to healthcare, and social protection during and after this crisis