Multimodal electromechanical model of piezoelectric transformers by Hamilton's principle

This work deals with a general energetic approach to establish an accurate electromechanical model of a piezoelectric transformer (PT). Hamilton’s principle is used to obtain the equations of motion for free vibrations. The modal characteristics (mass, stiffness, primary and secondary electromechanical conversion factors) are also deduced. Then, to illustrate this general electromechanical method, the variational principle is applied to both homogeneous and nonhomogeneous Rosen-type PT models. A comparison of modal parameters, mechanical displacements, and electrical potentials are presented for both models. Finally, the validity of the electrodynamical model of nonhomogeneous Rosen-type PT is confirmed by a numerical comparison based on a finite elements method and an experimental identification

First Approach for the Modelling of the Electric Field Surrounding a Piezoelectric Transformer in View of Plasma Generation

This paper is about an open multi-physics modelling problem resulting from recent investigations into plasma generation by piezoelectric transformers. In this first approach, the electric field distribution surrounding the transformer is studied according to a weak coupling formulation. Electric potential distribution views obtained numerically are compared to real views of plasma generation observed experimentally

Relaxation approximation of Friedrich's systems under convex constraints

This paper is devoted to present an approximation of a Cauchy problem for Friedrichs' systems under convex constraints. It is proved the strong convergence in L^2\_{loc} of a parabolic-relaxed approximation towards the unique constrained solution

Sociology and political science in the patrimonial society: implications of Piketty's Capital

What are the implications of Piketty's Capital for sociology and political science? Capital's argument focuses on the evolution of the r/g ratio (capital returns over growth rate) and outlines two modes of economic inequalities. One is characteristic of affluent (g > r) societies and the other is characteristic of patrimonial (r > g) societies. With the current return to a patrimonial society, corporations become political actors; occupational status and education's relevance are declining; the meaning of poverty is transformed, and welfare and punishment become interdependent means to social order; in politics, elitist theories gain traction; immigration is less about assimilation, and more about transnationalism and nationalist politics. We show that some theories are more relevant in an affluent society, and others are more adequate to a patrimonial society

Sociology and political science in the patrimonial society: implications of Piketty's Capital

What are the implications of Piketty's Capital for sociology and political science? Capital's argument focuses on the evolution of the r/g ratio (capital returns over growth rate) and outlines two modes of economic inequalities. One is characteristic of affluent (g > r) societies and the other is characteristic of patrimonial (r > g) societies. With the current return to a patrimonial society, corporations become political actors; occupational status and education's relevance are declining; the meaning of poverty is transformed, and welfare and punishment become interdependent means to social order; in politics, elitist theories gain traction; immigration is less about assimilation, and more about transnationalism and nationalist politics. We show that some theories are more relevant in an affluent society, and others are more adequate to a patrimonial society

Identification Methodology of Electrical Equivalent Circuit of the Piezoelectric Transformers by FEM

Methodology using Ansys analyses for the identification of Electrical Equivalent Circuit of piezoelectric transformer. The demonstration is done with typical multilayered Rosen transformer but the method is relevant for any kind of transformer structures

Experimental realization of an ideal Floquet disordered system

The atomic Quantum Kicked Rotor is an outstanding "quantum simulator" for the exploration of transport in disordered quantum systems. Here we study experimentally the phase-shifted quantum kicked rotor, which we show to display properties close to an ideal disordered quantum system, opening new windows into the study of Anderson physics.Comment: 10 pages, 7 figures, submitted to New Journal of Physics focus issue on Quantum Transport with Ultracold Atom

Ferguson et la nouvelle condition noire aux Etats-Unis

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