24,432 research outputs found
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
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
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
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
We define two graded Lie brackets on spaces of multilinear mappings.
The first one is able to recognize -graded associative algebras and their
modules and gives immediately the correct differential for Hochschild
cohomology. The second one recognizes -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
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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