261 research outputs found

    On spacetime transformation optics:temporal and spatial dispersion

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    The electromagnetic implementation of cloaking, the hiding of objects from sight by diverting and reassembling illuminating electromagnetic fields has now been with us ten years, while the notion of hiding events is now five. Both schemes as initially presented neglected the inevitable dispersion that arises when a designed medium replaces vacuum under transformation. Here we define a transformation design protocol that incorporates both spacetime transformations and dispersive material responses in a natural and rigorous way. We show how this methodology is applied to an event cloak designed to appear as a homogeneous and isotropic but dispersive medium. The consequences for spacetime transformation design in dispersive materials are discussed, and some parameter and bandwidth constraints identified

    Can soluble urokinase plasminogen receptor predict outcomes after cardiac surgery?

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    Acknowledgements: We thank Lisa Jolly, from the Institute of Infection, Immunity and Inflammation at the University of Glasgow who performed all lab analysis. We thank Professor John Kinsella for his contributions to this research. Funding: This work was supported by the National Institute of Academic Anaesthesia through the Royal College of Anaesthetists Research, Education and Travel grant via the Ernest Leach Fund to Dr Philip McCall. The funding body had no role in design of the study, collection, analysis and interpretation of data or writing of the manuscript.Peer reviewedPostprintPostprintPostprin

    RE 1265A C.J. Torno

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    Series 4.2, Box 30, Folder 329 Sale No. 339, File No. 1265a, C.J. Torno, Lexington, Texashttps://scholarworks.utrgv.edu/johnshary/1103/thumbnail.jp

    General Relativistic Contributions in Transformation Optics

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    One potentially realistic specification for devices designed with transformation optics is that they operate with high precision in curved space-time, such as Earth orbit. This raises the question of what, if any, role does space-time curvature play in determining transformation media? Transformation optics has been based on a three-vector representation of Maxwell's equations in flat Minkowski space-time. I discuss a completely covariant, manifestly four-dimensional approach that enables transformations in arbitrary space-times, and demonstrate this approach for stable circular orbits in the spherically symmetric Schwarzschild geometry. Finally, I estimate the magnitude of curvature induced contributions to satellite-borne transformation media in Earth orbit and comment on the level of precision required for metamaterial fabrication before such contributions become important.Comment: 14 pages, 3 figures. Latest version has expanded analysis, corresponds to published versio

    A new parameterisation for runup on gravel beaches

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    publisher: Elsevier articletitle: A new parameterisation for runup on gravel beaches journaltitle: Coastal Engineering articlelink: http://dx.doi.org/10.1016/j.coastaleng.2016.08.003 content_type: article copyright: Ā© 2016 The Authors. Published by Elsevier B.V. Open Access funded by Engineering and Physical Sciences Research Counci

    Groundwater dynamics in coastal gravel barriers backed by freshwater lagoons and the potential for saline intrusion: Two cases from the UK

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    ā€œNOTICE: this is the authorā€™s version of a work that was accepted for publication in Journal of Marine Systems. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Marine Systems, [VOL 123, (01.08.13)] DOI 10.1016/j.jmarsys.2013.04.004". The full text is under embargo until 01.08.15

    High-resolution, large-scale laboratory measurements of a sandy beach and dynamic cobble berm revetment

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    High quality laboratory measurements of nearshore waves and morphology change at, or near prototype-scale are essential to support new understanding of coastal processes and enable the development and validation of predictive models. The DynaRev experiment was completed at the GWK large wave flume over 8 weeks during 2017 to investigate the response of a sandy beach to water level rise and varying wave conditions with and without a dynamic cobble berm revetment, as well as the resilience of the revetment itself. A large array of instrumentation was used throughout the experiment to capture: (1) wave transformation from intermediate water depths to the runup limit at high spatio-temporal resolution, (2) beach profile change including wave-by-wave changes in the swash zone, (3) detailed hydro and morphodynamic measurements around a developing and a translating sandbar.</p
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