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 - Franck Vernerey (Boulder Univ.)
Active Mechanics of Cohesive Biological Aggregates : -The Case of Fire-Ant Swarms-
A majority of soft living materials owe their complex mechanical behavior to an underlying network structure. Despite this inherent complexity, the physical structure of these materials can often be conceptualized as dynamic physical networks, where nodes and connections are governed by simple rules. An advantage of such a network representation resides in its well-defined mathematical structure, enabling the use of the powerful machinery of statistical mechanics. This statistical approach, or transient network theory (TNT), provides a bridge to connect (simple) “network rules” to emerging (complex) “continuum response”. In dynamic polymer networks, topological bond rearrangement combined with chain elasticity is sufficient to explain the emerging elasticity, rheology, and time-dependent fracture of the material. Applying this approach to living materials is tempting but is challenging because of the diversity of mechanisms involved (cell signaling, reaction, diffusion, growth, …) and issues with direct observations and measurements.
This presentation will discuss our recent work on a biological yet simplified mechanical network (the raft) that solenopsis invicta (better known as fire ants) make with their own body to escape flooding. Like cellular systems, these networks are highly dynamic and active. As such, they are not only capable of adapting their viscoelastic response to load to avoid premature failure, but also display collective morphogenesis with the stochastic emergence of long protrusions from the raft's edge. Employing experimental characterization and our dynamic network model, we unveil a set of local rules that reproduces the emergence of these instabilities in the absence of external factors. Results suggest that collective morphogenesis in fire ant swarms emerge from a reduced set of rules at the network level. To conclude, we discuss the potential of the concept of dynamics network to better understanding active and living materials, and discuss potential applications to the development of decentralized, autonomous active matter and synthetic swarms.
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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