Magnetic forces in high-T(sub c) superconducting bearings

In September 1987 research at Cornell levitated a small rotor on superconducting bearing at 10,000 rpm. In April 1989 a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu3O7. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic drag forces of a magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the drag force reaches a constant value, independent of the speed. Dampling of lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time

Magnetic forces in high-Tc superconducting bearings

In September 1987, researchers at Cornell levitated a small rotor on superconducting bearings at 10,000 rpm. In April 1989, a speed of 120,000 rpm was achieved in a passive bearing with no active control. The bearing material used was YBa2Cu307. There is no evidence that the rotation speed has any significant effect on the lift force. Magnetic force measurements between a permanent rare-earth magnet and high T(sub c) superconducting material versus vertical and lateral displacements were made. A large hysteresis loop results for large displacements, while minor loops result for small displacements. These minor loops seem to give a slope proportional to the magnetic stiffness, and are probably indicative of flux pinning forces. Experiments of rotary speed versus time show a linear decay in a vacuum. Measurements of magnetic dipole over a high-T(sub c) superconducting disc of YBCO show that the lateral vibrations of levitated rotors were measured which indicates that transverse flux motion in the superconductor will create dissipation. As a result of these force measurements, an optimum shape for the superconductor bearing pads which gives good lateral and axial stability was designed. Recent force measurements on melt-quench processed superconductors indicate a substantial increase in levitation force and magnetic stiffness over free sintered materials. As a result, application of high-T(sub c) superconducting bearings are beginning to show great promise at this time

Analysis of edge impact stresses in composite plates

The in-plane edge impact of composite plates, with or without a protection strip, is investigated. A computational analysis based on the Fast Fourier Transform technique is presented. The particular application of the present method is in the understanding of the foreign object damage problem of composite fan blades. The method is completely general and may be applied to the study of other stress wave propagation problems in a half space. Results indicate that for the protective strip to be effective in reducing impact stresses in the composite the thickness must be equal or greater than the impact contact dimension. Large interface shear stresses at the strip - composite boundary can be induced under impact

Green Universities and eco-friendly learning: from league tables to eco-entrepreneurship education

The United Nations World Summit, 2005, advocated equipping students with the knowledge and understanding, skills and attributes needed to work and live in a way that safeguards environmental, social and economic wellbeing. 2014 marked the 10th and final year of the UN Decade for Education for Sustainable Development; with over two thirds of students surveyed believing that sustainable development should be covered in their degree courses (surveyed in 2010, 2011 and 2012, People & Planet, 2015). This paper outlines recent developments in incorporating green business, sustainable products and eco-entrepreneurship into HEI business school curricula. The focus is survey research of n=150 students at one HEI in the UK, and interviews with the Head of Estates and the Director of Student Engagement, to ascertain student attitudes towards the introduction of ‘green business’ modules; and the views of senior staff on student engagement in environmental improvements. The results are mapped onto two dimensions (interest in the environment and interest in a green module) and four conceptual domains (colour coded - red, yellow, light green, dark green) to exemplify the differentiation in student attitudes; and the concomitant need to develop different strategies for implementing curriculum development. Results indicate the majority of students in the sample displayed negative attitudes towards curriculum development in this regard. In general, red classified students (‘cynical’) tended to see curriculum development in this area as irrelevant; yellow (‘instrumentalist’) and dark green (‘advocate’) were more positive. Light green (‘complacent’) tended to feel they had enough environmental awareness without further curriculum development. Implications for curriculum development, student engagement, and plans for improving the green rating of the target HEI are provided by reviewing current KPI data against the top performing HEI in the UK (Green Planet index, 2015). The results are applicable to other HEIs across Europe

Enterprise and entrepreneurship education: implications for innovation in delivery

This paper studies current provision of enterprise and entrepreneurship education at one university and provides recommendations for curriculum development across several different subject areas. The paper reviews the Quality Assurance Agency for Higher Education (2012) report Enterprise and entrepreneurship education: Guidance for higher education providers; and the recent All-Party Parliamentary Action Group for Micro Businesses report (2014) An Education System fit for An Entrepreneur. The former report highlights the importance of four factors concerning the students learning experience (enterprise awareness, developing an entrepreneurial mind-set, developing entrepreneurial capability, entrepreneurial effectiveness) and relates these to graduate outcomes (behaviours, attributes, skills).The approach of this research is to map existing delivery in three subjects against the above factors and consider what gaps can be plugged and how. Thus the approach is largely a mapping exercise but includes primary interviews with four senior managers (n=4) and a sample of students (n=42) to elicit their feedback on changes in delivery. The results provide a basis for curriculum development planning applicable to the particular subjects involved. However, implications are stated for how other subject areas can innovate in three key areas of HE provision (teaching, learning, and assessment) in order to improve the effectiveness of entrepreneurs and the employability of graduates in general. The value of the report is in highlighting key aspects of current delivery that can be improved through enhanced student learning, and improved delivery, around the theme of enterprise and entrepreneurship education

'Rio+25', the global compact in Brazil and opportunities presented by the UN Sustainable Development Goals

This chapter highlights the significance of creativity, innovation and collaboration in the development of sustainable solutions; and the role and mindset of the eco and social entrepreneur in enterprise and entrepreneurship education. Several research questions are posed: what is the history of CSR in Brazil? What current CSR issues are being faced in Brazil? Can tools such as the UN SDGs provide a way of bridging any gaps in CSR provision? What implications are there for ecosystem development in support of CSR? The methodology is thus based on literature review, case analysis, and conceptual overview focussing on instrumental approaches. The chapter concludes that ecosystems need to evolve to ensure that Higher Education Institutions develop and support the necessary eco and social entrepreneurial mindsets needed for sustainable innovation

100 Global innovative sustainability projects: evaluation and implications for entrepreneurship education

New mindsets and innovative thinking (Moon. 2013, 2014) are needed to deliver on everything from good health and well-being to affordable and clean energy. This paper reviews the latest trends to tackling pressing social and environmental problems by examining a sample of 100 innovative projects across the globe. The data set of 100 projects allows for evaluation by both quantitative and qualitative methods. Thus the projects are evaluated on their innovation contribution but also on their scalability going forward. Implications for the resources needed to ensure such projects continue to be developed across the globe are discussed; and the green skills needed to ensure their success. The projects cover a range of applications including Buildings, Food, Energy, Transportation but also Resource and Education sectors. The Circular Economy concept is used to identify commonalities between the projects. And key challenges in the development and deployment of the solutions are highlighted. The key research question is: what strategic policy support is needed within HEIs to ensure the development of the necessary multi collaborative and cross disciplinary mind-sets and skills that such projects require

Notes on Spinoptics in a Stationary Spacetime

In arXiv:1105.5629, equations of the modified geometrical optics for circularly polarized photon trajectories in a stationary spacetime are derived by using a (1+3)-decomposed form of Maxwell's equations. We derive the same results by using a four-dimensional covariant description. In our procedure, the null nature of the modified photon trajectory naturally appears and the energy flux is apparently null. We find that, in contrast to the standard geometrical optics, the inner product of the stationary Killing vector and the tangent null vector to the modified photon trajectory is no longer a conserved quantity along light paths. This quantity is furthermore different for left and right handed photon. A similar analysis is performed for gravitational waves and an additional factor of 2 appears in the modification due to the spin-2 nature of gravitational waves.Comment: 15 pages, to appear in PR