Through the measurement of the averaged bond order parameter for the different confinement geometries, it has been shown that cell geometry strongly affects the ordering of the system. The grain organization was analyzed after a slow cooling process. Concerning the confinement shape, triangular, square, pentagonal, hexagonal, heptagonal, and circular geometries have been considered. The effect of both confinement size and shape on the grains' organization in the low-energy state has been investigated. Therefore, the balance between magnetic interaction and agitation allows investigating 2d phases through direct visualization. A two-dimensional (2d) Brownian motion is induced by horizontal mechanical vibrations. The grains are confined by repulsing walls and are homogeneously distributed inside the cell. The particles are millimeter-scale grains interacting through the short range magnetic dipole-dipole potential induced by an external magnetic field. We present a systematic experimental study of the confinement effect on the crystallization of a monolayer of magnetized beads. TroisiГЁmement, la puissance injectГ©e pour maintenir le systГЁme dans un Г©tat stationnaire hors Г©quilibre peut ГЄtre reliГ© simplement Г certaines quantitГ©s physiques de la suspension, et montre que l'injection de l'Г©nergie se fait de la mГЄme maniГЁre quelque soit la phase ou le rГ©gime de fluctuations de la suspension. L'analyse de la morphologie de ces structures rГ©vГЁlent une invariance d'Г©chelle et a permis d'extraire plusieurs exposants critiques Г l'aide d'outils de la thГ©orie de la percolation. Ces hГ©tГ©rogГ©nГ©itГ©s sont constituГ©es d'amas de particules localement cristallisГ©es dans une phase fluide dГ©sordonnГ©e. DeuxiГЁmement, le systГЁme exhibe une transition de phase ordre/dГ©sordre caractГ©risГ©e par de grandes fluctuations et des hГ©tГ©rogГ©nГ©itГ©s qui Г©mergent proche du point critique. Dans ce dernier rГ©gime, la suspension se comporte de maniГЁre additive : il n'existe pas de corrГ©lations Г longue portГ©e sur les fluctuations de densitГ©, ce qui est Г©tonnant dans une suspension oГ№ les corrГ©lations de vitesses sont connues pour ГЄtre Г longue portГ©e.

De plus, la dГ©pendance de cette tempГ©rature aux diffГ©rentes quantitГ©s physiques du problГЁme montre qu'il existe deux rГ©gimes de fluctuations, que nous interprГ©tons comme des rГ©gimes inertiels et visqueux. Cette Г©quation dвЂ™Г©tat rГ©vГЁle lвЂ™existence dвЂ™interactions interactions attractives entre les particules.

L'analyse de la distribution spatiale des particules a montrГ© quвЂ™il existe une Г©quation dвЂ™Г©tat reliant la densitГ© de particules et deux autres quantitГ©s mesurables que nous interprГ©tons comme une tempГ©rature et une pression granulaire. Les comportements thermiques d'une suspension granulaire en deux dimensions maintenue dans un Г©tat stationnaire hors Г©quilibre ont Г©tГ© Г©tudiГ©s expГ©rimentalement. We conclude by summarizing different key events in the fetal development of the ENS and the role played by mechanics in the morphogenesis of this unique nerve network. We find that the longitudinal anisotropy of the ENS vanishes when contractile waves are suppressed in organ culture, showing that these contractile forces play a key role in sculpting the developing ENS.

We image the deformations of the ENS during spontaneous myogenic motility and show that circular smooth muscle contractile waves induce longitudinal strain on the ENS network we rationalize this behavior by mechanical finite element modeling of the incompressible gut wall. We find that the number of enteric ganglia is fixed early in development and that subsequent ENS morphogenesis consists in the anisotropic expansion of a hexagonal honeycomb (chicken) or a square (mouse) lattice, without de-novo ganglion formation. Because it is known that mechanical forces can have long reaching effects on neural growth, we investigate here how contractions of the circular smooth muscle of the gut impact morphogenesis of the developing fetal ENS, in chicken and mouse embryos. Neurons and glia of the enteric nervous system (ENS) are constantly subject to mechanical stress stemming from contractions of the gut wall or pressure of the bolus, both in adulthood and during embryonic development.

Kinetic energy of particles