Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userStiffest Elastic Networks
172
0
0.0
(
0
)
Authors
Gerald Gurtner
Ask ChatGPT about the research
No Arabic abstract
The rigidity of a network of elastic beams crucially depends on the specific details of its structure. We show both numerically and theoretically that there is a class of isotropic networks which are stiffer than any other isotropic network with same density. The elastic moduli of these textit{stiffest elastic networks} are explicitly given. They constitute upper-bounds which compete or improve the well-known Hashin-Shtrikman bounds. We provide a convenient set of criteria (necessary and sufficient conditions) to identify these networks, and show that their displacement field under uniform loading conditions is affine down to the microscopic scale. Finally, examples of such networks with periodic arrangement are presented, in both two and three dimensions.
rate research
Read More
Demixing of multicomponent biomolecular systems via liquid-liquid phase separation (LLPS) has emerged as a potentially unifying mechanism governing the formation of several membrane-less intracellular organelles (condensates), both in the cytoplasm (e.g., stress granules) and in the nucleoplasm (e.g., nucleoli). While both in vivo experiments and studies of synthetic systems demonstrate that LLPS is strongly affected by the presence of a macromolecular elastic network, a fundamental understanding of the role of such networks on LLPS is still lacking. Here we show that, upon accounting for capillary forces responsible for network expulsion, small-scale heterogeneity of the network, and its nonlinear mechanical properties, an intriguing picture of LLPS emerges. Specifically, we predict that, in addition to the experimentally observed cavitated droplets which fully exclude the network, two other phases are thermodynamically possible: elastically arrested, size-limited droplets at the network pore scale, and network-including macroscopic droplets. In particular, pore size-limited droplets may emerge in chromatin networks, with implications for structure and function of nucleoplasmic condensates.
A model of an autonomous three-sphere microswimmer is proposed by implementing a coupling effect between the two natural lengths of an elastic microswimmer. Such a coupling mechanism is motivated by the previous models for synchronization phenomena in coupled oscillator systems. We numerically show that a microswimmer can acquire a nonzero steady state velocity and a finite phase difference between the oscillations in the natural lengths. These velocity and phase difference are almost independent of the initial phase difference. There is a finite range of the coupling parameter for which a microswimmer can have an autonomous directed motion. The stability of the phase difference is investigated both numerically and analytically in order to determine its bifurcation structure.
We consider three-dimensional reshaping of thin nemato-elastic sheets containing half-charged defects upon nematic-isotropic transition. Gaussian curvature, that can be evaluated analytically when the nematic texture is known, differs from zero in the entire domain and has a dipole or hexapole singularity, respectively, at defects of positive or negative sign. The latter kind of defects appears in not simply connected domains. Three-dimensional shapes dependent on boundary anchoring are obtained with the help of finite element computations.
We discuss the directional motion of an elastic three-sphere micromachine in which the spheres are in equilibrium with independent heat baths having different temperatures. Even in the absence of prescribed motion of springs, such a micromachine can gain net motion purely because of thermal fluctuations. A relation connecting the average velocity and the temperatures of the spheres is analytically obtained. This velocity can also be expressed in terms of the average heat flows in the steady state. Our model suggests a new mechanism for the locomotion of micromachines in nonequilibrium biological systems.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
