Micellar shape change in an amphiphilic solution is investigated by a molecular dynamics simulation of coarse-grained semiflexible amphiphilic molecules with explicit solvent molecules. Our simulations show that a cylindrical micelle is obtained at small molecular rigidity while a disc-shaped micelle appears at large molecular rigidity. We find that most chains are in an extended conformation a...

In this paper, we present a sufficient condition for the universal rigidity of a generic bar framework G(p) in terms of the Gale matrix Z corresponding to G(p). We also establish a relationship between the stress matrix S and the Gale matrix Z for bar frameworks. This allows us to translate back and forth between S and Z in recently obtained results concerning universal rigidity, global rigidit...

The geometry of cavities in the surfaces of proteins facilitates a variety of biochemical functions. To better understand the biochemical nature of protein cavities, the shape, size, chemical properties, and evolutionary nature of functional and nonfunctional surface cavities have been exhaustively surveyed in protein structures. The rigidity of surface cavities, however, is not immediately ava...

In this paper we provide a Liouville type theorem in the framework of fracture mechanics, and more precisely in the theory of SBV deformations for cracked bodies. We prove the following rigidity result: if u ∈ SBV (Ω, RN ) is a deformation of Ω whose associated crack Ju has finite energy in the sense of Griffith’s theory (i.e., HN−1(Ju) <∞), and whose approximate gradient ∇u is almost everywher...

This article summarizes the presently available general theory of rigidity of 3dimensional structures. We explain how a structure, for instance a bar and joint structure, can fail to be rigid for two quite different types of reasons. First, it may not have enough bars connecting certain sets of nodes. That is, it may faij for topologlcrl reasons. Secondly,. although it may “count” correctly, it...

Rigidity is one of the major signs of P a r k i n s o n ’s disease (PD). However, its pathophysiology has rarely been studied. This appears a little surprising since data obtained from animal physiology, which offers a scheme of neuronal circuits that might be hyperor hypoactive, could be useful in the study of muscle tone problems, a classical area in neurological semiology. Experimental model...

Aiming at demonstrating the potential of unidirectional natural fiber-reinforced thermoplastic composites in structural applications, textile flax yarn/thermoplastic polyester composites with variable fiber volume fractions have been manufactured by a filament-winding process followed by a vacuum-assisted compression molding process. The microstructure of the composites shows that the flax fibe...

The stabilization of slopes by vegetation has been a topical issue for many years. Root mechanical characteristics significantly influence soil reinforcement; therefore it is necessary to research into the indicators of root tensile properties. In this study, we explored the influence of root moisture content on tensile resistance and strength with different root diameters and for different tre...

We distinguish between, and discuss the applicability of, two levels of rigidity in rigid-body collision modeling. For rigidity in the strong, force-response, sense collisional contact deformations must be highly localized. The bodies then move according to second order rigid-body mechanics during the collision. Incremental collision laws and most collision models using continuum mechanics for ...