24,432 research outputs found

    Nietzsche and the Vicious Circle

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    Short Description of the Mines of Precious Stones, in the District of Kyat-pyen, in the Kingdom of Ava, by Pere Giuseppe d'Amato, edited by Michael W. Charney

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    This first-hand communication from Giuseppe d’Amato appears to have been written originally in Italian. It was translated for publication in the Journal of the Asiatic Society of Bengal in 1833, although the translator’s name is not provided. However short this account, it provides valuable detailed information mining in royal Burma as well as a few hints concerning Chinese traders in Upper Burma

    Critical and sustainable fluxes: theory, experiments and applications

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    Over the last ten years, numerous membrane filtration data have been viewed in the light of the concept of critical flux. This concept, used in a number of different ways often without explicit redefinition, is here clarified both from a theoretical and from an experimental viewpoint. Also, a link is make with the sustainable fluxes. Also covered are the various methods of measurement and the influence of membrane and suspension properties on the critical flux. Over the same period of time, models have been developed to explain the observed behaviour. Those for stable colloidal suspensions are based on the existence of repulsive interactions between soft matter constituents. The assumptions and usefulness of various models are discussed. The concept of a critical concentration for phase transition is introduced into the theoretical discussion. For theoreticians and experimentalist, this and the clarified concept of a small set of critical fluxes will continue to provide a valuable framework. For membrane users dealing with most industrial process streams (mixtures and complex fluid) the concept of a sustainable flux (shown as being derived from critical flux) is of a great utility; above a certain key flux (dependent on hydrodynamics, feed conditions and process time) the rate of fouling is economically and environmentally unsustainable. For many, knowledge of the point below which no major irreversible fouling occurs (the critical flux) in a membrane separation will always be of greatest utility

    Minimization variational principles for acoustics, elastodynamics, and electromagnetism in lossy inhomogeneous bodies at fixed frequency

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    The classical energy minimization principles of Dirichlet and Thompson are extended as minimization principles to acoustics, elastodynamics and electromagnetism in lossy inhomogeneous bodies at fixed frequency. This is done by building upon ideas of Cherkaev and Gibiansky, who derived minimization variational principles for quasistatics. In the absence of free current the primary electromagnetic minimization variational principles have a minimum which is the time-averaged electrical power dissipated in the body. The variational principles provide constraints on the boundary values of the fields when the moduli are known. Conversely, when the boundary values of the fields have been measured, then they provide information about the values of the moduli within the body. This should have application to electromagnetic tomography. We also derive saddle point variational principles which correspond to variational principles of Gurtin, Willis, and Borcea.Comment: 32 pages 0 figures (Previous version omitted references

    The multigraded Nijenhuis-Richardson Algebra, its universal property and application

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    We define two (n+1)(n+1) graded Lie brackets on spaces of multilinear mappings. The first one is able to recognize nn-graded associative algebras and their modules and gives immediately the correct differential for Hochschild cohomology. The second one recognizes nn-graded Lie algebra structures and their modules and gives rise to the notion of Chevalley cohomology

    Chiral anomalies on a circle and their cancellation in F-theory

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    We study in detail how four-dimensional local anomalies manifest themselves when the theory is compactified on a circle. By integrating out the Kaluza-Klein modes in a way that preserves the four-dimensional symmetries in the UV, we show that the three-dimensional theory contains field-dependent Chern-Simons terms that appear at one-loop. These vanish if and only if the four-dimensional anomaly is canceled, so the anomaly is not lost upon compactification. We extend this analysis to situations where anomalies are canceled through a Green-Schwarz mechanism. We then use these results to show automatic cancellation of local anomalies in F-theory compactifications that can be obtained as a limit of M-theory on a smooth Calabi-Yau fourfold with background flux.Comment: 39 pages, 3 figures. v2: references added and typos correcte
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