Acoustic thermometry for detecting quenches in superconducting coils and conductor stacks

Quench detection capability is essential for reliable operation and protection of superconducting magnets, coils, cables, and machinery. We propose a quench detection technique based on sensing local temperature variations in the bulk of a superconducting winding by monitoring its transient acoustic response. Our approach is primarily aimed at coils and devices built with high-temperature superconductor materials where quench detection using standard voltage-based techniques may be inefficient due to the slow velocity of quench propagation. The acoustic sensing technique is non-invasive, fast, and capable of detecting temperature variations of less than 1 K in the interior of the superconductor cable stack in a 77 K cryogenic environment. We show results of finite element modeling and experiments conducted on a model superconductor stack demonstrating viability of the technique for practical quench detection, discuss sensitivity limits of the technique, and its various applications

The research-teaching nexus revisited

This chapter explores the idea of the research–teaching nexus, which provides the foundation for research-based approaches to education, such as UCL’s Connected Curriculum. Although this is an idea that can be traced back across two centuries, it remains controversial, and its feasibility is still questioned. However, research has developed an increasingly sophisticated account of the various strands that this ‘nexus’ consists of, and how students experience it. These strands will be reviewed to identify opportunities for building connections between research and teaching

Reflecting on things: Sociomaterial perspectives on academic development

The aims, discourse and practices of academic development in higher education rest on a series of assumptions about the nature of academic practice and student engagement, assumptions which shape its approaches to enhancement and change. In this chapter, we review and critique these, drawing on sociomaterial theory and evidence from a project that explored the academic practices of students and staff

Students' physical and digital sites of study: Making, marking, and breaking boundaries

This chapter argues that studying draws in a wide array of technologies, takes place in both institutional and personal settings, and involves the consumption and production of a variety of digital and print texts. Knox exploring educational discourses about openness challenged the negative way in which discussions of technology framed the idea of liberty. The post-human, sociomaterial perspective Gourlay uses highlights another important principle: the idea that things such as technology also need to be treated as actors in social processes. The study received institutional ethical clearance and followed British Education Research Association (BERA) guidelines about informed consent, including guarantees of anonymity and confidentiality, and the right to opt out at any point. Rather than being bound within educational institutions, studying spills out across many public and private spaces, moored as part of a consistent practice of education by the consistent uses of print and digital technologies

Expansion tube test time predictions

The interaction of an interface between two gases and strong expansion is investigated and the effect on flow in an expansion tube is examined. Two mechanisms for the unsteady Pitot-pressure fluctuations found in the test section of an expansion tube are proposed. The first mechanism depends on the Rayleigh-Taylor instability of the driver-test gas interface in the presence of a strong expansion. The second mechanism depends on the reflection of the strong expansion from the interface. Predictions compare favorably with experimental results. The theory is expected to be independent of the absolute values of the initial expansion tube filling pressures

Wave Climate at Moffat Beach

The analysis of a series of wave recordings made at Moffat Beach, Queensland using an OSPOS wave recorder during 1963-1964 is described. This analysis included (i) the establishment of representative parameters for each wave recording; (ii) the determination of the frequency of occurrence of the representative parameters over the total recording period and (iii) the comparison of the recorded data with visual observations at Cape Moreton and the adjustment of the frequency curves to a longer more Queensland coast cannot be recommended.representative period of time.The results of the analysis provide confirmation of the\ua0applicability of the Rayleigh distribution to the short term wave\ua0height distribution within a given wave recording. On the other hand\ua0no definite conclusions are made concerning which theoretical\ua0representation of the long term wave height frequency of occurrence\ua0is to be preferred.The data analysed shows that at least four distinct types\ua0of wave conditions make up the overall wave climate in this area. The\ua0general wave height and period characteristics representative of these\ua0conditions together with seasonal variations are presented.The Moffat Beach wave data is compared with that obtained off\ua0the Gold Coast using Wave Rider buoys. Generally similar values of\ua0significant wave height are found but the wave periods are appreciably\ua0different. An analysis of possible explanations for this difference\ua0suggests that the filter effect due to pressure attenuation almost\ua0completely removes local wind generated seas from the OSPOS records.\ua0The question of a representative wave period for a given wave recording\ua0is considered and it is concluded that the use of the zero crossing\ua0period Tz\ua0for the analysis of unfiltered surface wave recordings of\ua0simultaneous sea and swell such as generally occurs off the southern\ua0Queensland coast cannot be recommended

Sociomaterial Texts, Spaces and Devices: Questioning ‘Digital Dualism’ in Library and Study Practices

Work on students' study practices posits the digital and material as separate domains, with the ‘digital’ assumed to be disembodied, decontextualised and free-floating, and spaces in the material campus positioned as prototypically ‘traditional’ and analogue. Libraries in particular are often characterised as symbolic of predigital literacy practices and forms of meaning making. This binary oversimplifies student engagement, particularly in relation to their creation of and interactions with texts. Two studies illustrate this: an investigation of student and staff textual practices that explored the complex and emergent networks they created, adapted and maintained; and one that explored perceptions and use of library spaces (digital and physical). A sociomaterial analysis shows the ongoing importance of institutional, personal and public spaces. This demonstrates that in order to enhance the student experience, a more nuanced understanding of the complex, emergent relationships between digital and print, device and user, and author and text is required

Introducing risk management into the grid

Service Level Agreements (SLAs) are explicit statements about all expectations and obligations in the business partnership between customers and providers. They have been introduced in Grid computing to overcome the best effort approach, making the Grid more interesting for commercial applications. However, decisions on negotiation and system management still rely on static approaches, not reflecting the risk linked with decisions. The EC-funded project "AssessGrid" aims at introducing risk assessment and management as a novel decision paradigm into Grid computing. This paper gives a general motivation for risk management and presents the envisaged architecture of a "risk-aware" Grid middleware and Grid fabric, highlighting its functionality by means of three showcase scenarios

Reaction-induced surface reconstruction of silver in contact with zirconium

When two solid metals are in contact at high temperature, interdi usion occurs leading in some cases to the growth of intermetallic compounds. The study of nucleation, growth and properties of these intermetallic compounds are of interest since it can be critical for many applications in industries. Yet, the e ect of these reactions on the initial surfaces of both metals is not well understood and particularly when surfaces are not perfectly flat and for short contact time. The purpose of the present study is to demonstrate that the growth of an intermetallic compound layer between to solid metals can lead to the surface reconstruction of one of them. The silver–zirconium system will be presented in order to illustrate this new phenomenon. The e ect of contact point on the di usion- reaction process has been modelled by patterning the Zr surface. The nucleation and growth of the intermetallic compounds occur along the contact points which leads to silver surface reconstruction with the growth of the preferential crystal planes f 111 g ad f 100 g . A model explaining this new phenomenon is developed based on the minimisation of Gibbs energy and the di usion rates af both Ag & Zr atoms in the binary system Ag / Zr