Adaptive two- and three-dimensional multiresolution computations of resistive magnetohydrodynamics

International audienceFully adaptive computations of the resistive magnetohydrodynamic (MHD) equations are presented in two and three space dimensions using a finite volume discretization on locally refined dyadic grids. Divergence cleaning is used to control the incompressibility constraint of the magnetic field. For automatic grid adaptation a cell-averaged multiresolution analysis is applied which guarantees the precision of the adaptive computations, while reducing CPU time and memory requirements. Implementation issues of the open source code CARMEN-MHD are discussed. To illustrate its precision and efficiency different benchmark computations including shock-cloud interaction and magnetic reconnection are presented

Natural discrete differential calculus in physics

International audienceWe sharpen a recent observation by Tim Maudlin: differential calculus is a natural language for physics only if additional structure, like the definition of a Hodge dual or a metric, is given, but the discrete version of this calculus provides this additional structure for free

Moyal Planes are Spectral Triples

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Frontières et (dé/re)construction - l'espacentre - concept et modélisation

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La sélection des ‘élus’ de l’ouverture sociale dans l’espace du journalisme. Le cas de La Chance

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Arpi. Formes et modes de vie d’une cité italiote (IVe‑IIe siècle av. n. è.). Campagne d’étude 2023

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Electron Delocalization and Electrochemical Potential Distribution Phenomena in Faradaic Electrode Materials for Understanding Electrochemical Behavior

International audienceElectrochemical energy storage devices are built upon the foudations of batteries and supercapacitors. In the past decade, new pseudocapacitor‐like electrodes are intensively developed to obtain superior energy storage performance. Pseudocapacitive matarials store charge through Faradaic processes, while the electrochemical signal remains like electrochemical double‐layer capacitors (EDLCs). To address this controversy, an analytical model is introduced for evaluating the voltammograms of electrode materials. Given this, the work focuses on understanding the origin of the pseudocapacitive phenomena in the cyclic voltammetry (CV) electrochemical signal. Based on electron transfer mechanism and tunnelling effect within the atomic structure, pseudocapacitive matarials possess a high electron delocalization possibility related to the redox centers number and initiates the electrochemical potential distribution among neighboring redox sites, which is consequently observed in the electrochemical signal as the plateau feature in CV, like EDLC. First, the determination of the capacitive tendency of various electrode materials is proposed, which turns out to be relative to the redox centers number (n) and total charge (Z). Here, when this number is large, electron hopping will very likely happen. The developed model is versatile to predict rate/potential regimes for the maximum faradaic storage, and then well differentiates the pseudocapacitive and battery materials

Après le CSE… le CS2E (comité social, économique et environnemental)

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A Contribution to the Pasteur-Pouchet Controversy: Pouchet as a philosopher and historian of the natural sciences

International audienceBuilding upon Raynaud’s analysis of the controversy between Pasteur and Pouchet over spontaneous generation, I single out the philosophical and historical reasons which led Pouchet to defend the idea that life can appear in the absence of parents. In particular, I retrace the theological arguments used by Pouchet for showing that spontaneous generation copes with the Christian doctrine. Then, I provide an outline of Pouchet’s interpretation of the development of natural sciences in the Middle Ages. Finally, I argue that Pouchet’s endorsement to spontaneous generation was determined by his looking upon Albert the Great’s philosophical and scientific heritage as a combination of both theological orthodoxy and experimental attitude, a mix that satisfies the metaphysical and epistemological tenets of Pouchet’s philosophy of the natural sciences

L'éclosion du contentieux constitutionnel

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