ESPCI web site
Le séminaire hebdomadaire du laboratoire PMMH a lieu tous les vendredis à 11h, au premier étage Barre Cassan, campus Jussieu (plan).
Stéphane Perrard
Etienne Reyssat
Virgile Thiévenaz
PMMH
BARRE CASSAN
BAT A 1ER ETAGE CASE 18
7 QUAI SAINT BERNARD
75005 PARIS
France
Tel : (33) 1 40 79 45 22
Séminaire PMMH - Anaël Lemaître (Laboratoire Navier, ENPC)
Structural relaxation is a scale-free process
Structural relaxation is the process via which a liquid explores its
equilibrium ensemble. It is responsible for the dramatic slowing down at
the glass transition, and has thus received a quite considerable amount
of attention. Yet, the mechanisms governing relaxation are still largely
unknown.
We will explore liquid relaxation from the viewpoint that it results
from a series of transitions which are akin to solid-solid
transformations. This idea arises because, at low temperatures, liquids
spend most of the time vibrating around local minima (inherent states,
or ISs) of their potential energy surface. Since inherent states are, by
definition, mechanically stable, they are genuine elastic solids. Hence,
relaxation results from a series of transitions between elastic solids,
and it follows that relaxation events should leave elastic imprints in
the surrounding medium. To support this view, we carry out a systematic
analysis of the statics and dynamics of the inherent stress field
obtained from 2D and 3D numerical simulations.
Our first surprise is that the inherent stress field itself presents
anisotropic and long-ranged (power-law) correlations, which are a clear
indication of elasticity. Moreover, we directly observe that relaxation
events create long-ranged and anisotropic stresses in the surrounding
medium, just like solid-solid transformations. Finally, we can
demonstrate that the relaxation events occurring over finite time
windows are power-law correlated in space. It follows that the
relaxation process is non-local, an observation which comes against the
currently widely held belief that relaxation would decorrelate beyond
some finite length scale. Our work brings evidence that elasticity plays
a crucial role in liquid relaxation.
Séminaires (4)
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Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Francesca Borghi Università degli Studi di Milano
Vendredi 20 juin de 11h00 à 12h00 - Salle réunion PMMH 1
REPROGRAMMABLE HARDWARE FOR DATA PROCESSING AT THE EDGE : A NEW COMPUTING PARADIGM BASED ON NEUROMORPHIC SYSTEMS
The brain's ability to perform efficient and fault-tolerant data processing is strongly related with its peculiar interconnected adaptive architecture, based on redundant neural circuits interacting at different scales. By emulating the brain's processing and learning mechanisms, computing technologies strive to (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…) -
Séminaire PMMH - Salvatore Federico (University of Calgary, Canada)
Vendredi 4 juillet de 11h00 à 12h00 - Salle réunion PMMH 1
Continuum Mechanics of Hydrated Fibre-Reinforced Soft Tissues
Biological tissues can be represented as bi-phasic continua, with a porous solid phase saturated by an interstitial fluid and reinforced by collagen fibers. This lecture will give an overview of the modelling techniques for fibre-reinforced porous composite materials with statistical orientation of the fibers. Both (…)
Instructions générales pour les conférenciers
Le public du séminaire est très hétérogène (rien qu’au PMMH nous travaillons sur des thématiques très diverses, mécanique des fluides, des milieux granulaires, des solides, physique statistique, physique du mouillage, micro-fluidique, biophysique,...) l’objectif est donc de ne pas faire un séminaire trop spécialiste : au moins la première moitié du séminaire à un niveau accessible pour celui qui ne connaît rien sur le sujet.
Le séminaire a lieu à 11h. rendez-vous 15 minutes avant pour installer et tester la projection.
Le séminaire dure environ 45 minutes pour laisser un peu de temps pour discuter à la fin.
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- Séminaire de Mécanique des Fluides de l’Institut Jean le Rond d’Alembert
- Séminaires du laboratoire MSC, Paris VII
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