270 research outputs found
Limpieza y restauración con láser
Los primeros trabajos referidos a la limpieza y restauración con láser de objetos de valor patrimonial datan de mediados de la década del 70. Sin embargo es recién en los últimos años que se observa una evolución sistemática tanto en las investigaciones relacionadas con el tema, como en el desarrollo de equipos láser versátiles y compactos para este tipo de aplicaciones. Simultáneamente en este período se asiste a una consolidación de los conocimientos vinculados a los procesos de interacción lásermateria involucrados en estos tratamientos.
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Optimal design for active damping in sandwich structures using the Direct MultiSearch method
This paper addresses the problem of optimal positioning of surface bonded piezoelectric patches in sandwich plates with viscoelastic core and laminated face layers. The objective is to maximize a set of modal loss factors for a given frequency range using multiobjective topology optimization. Active damping is introduced through co-located negative velocity feedback control. The multiobjective topology optimization problem is solved using the Direct MultiSearch Method. An application to a simply supported sandwich plate is presented with results for the maximization of the first six modal loss factors. The influence of the finite element mesh is analyzed and the results are, to some extent, compared with those obtained using alternative single objective optimization
Semiclassical thermodynamics of scalar fields
We present a systematic semiclassical procedure to compute the partition
function for scalar field theories at finite temperature. The central objects
in our scheme are the solutions of the classical equations of motion in
imaginary time, with spatially independent boundary conditions. Field
fluctuations -- both field deviations around these classical solutions, and
fluctuations of the boundary value of the fields -- are resummed in a Gaussian
approximation. In our final expression for the partition function, this
resummation is reduced to solving certain ordinary differential equations.
Moreover, we show that it is renormalizable with the usual 1-loop counterterms.Comment: 24 pages, 5 postscript figure
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