This study is aimed at clarifying the relative importance of the specific character of the nuclei and of the duration of supercooling in heterogeneous freezing nucleation by immersed impurities. Laboratory experiments were carried out in which sets of water drops underwent multiple cycles of freezing and melting. The drops contained suspended particles of mixtures of materials; the resulting fr...

The immersed boundary method is an algorithm for simulating the interaction of immersed elastic bodies or boundaries with a viscous incompressible fluid. The immersed elastic material is represented in the fluid equations by a system or field of applied forces. The particular case of Stokes flow with applied forces on a periodic domain involves two related mathematical complications. One of the...

Microtubule gliding assays, in which molecular motors anchored to a plate drive the gliding motion of filaments in a quasi-two-dimensional fluid layer, have been shown to organize into a variety of large-scale patterns. We derive a fully three-dimensional multiscale coarse-grained model of a gliding assay including the evolution of densities of rigid filaments, bound motors, and free motors, co...

Many industrial and technological applications require precise determination of the viscosity and density of liquids. Such measurements can be time consuming and often require sampling substantial amounts of the liquid. These problems can partly be overcome with the use of microcantilevers but most existing methods depend on the specific geometry and properties of the cantilever, which renders ...

About fifty years ago Ringer demonstrated experimentally in a striking way that sodium, calcium and potassium were essential for the contraction of the heart muscle. He found that when the concentration of potassium was increased in the solution in which the heart was immersed the contractions decreased, and if the concentration was further increased the contractions became weaker and weaker, t...

We develop computational methods for the simulation of osmotic swelling phenomenarelevant to microscopic vesicles containing transformable solute molecules. We introduce StochasticImmersed Boundary Methods (SIBM) that can capture osmotically driven fluid transport throughsemi-permeable elastic membranes subject to thermal fluctuations. We also develop numerical meth-ods to handl...

Can there be infinitely many minimal hypersurfaces with a given boundary in a Riemannian manifold? A number of previous results, positive and negative, already indicated that the answer depends on the definition of surface, on orientability, on stability and minimizing properties of the surface, on the smoothness and geometry of the boundary, and on the ambient manifold. 1. Finiteness for area-...

We present results from a series of compute-intensive simulation experiments employing a realistic and detailed three-dimensional model of the human cochlear macro-mechanics. Our model uses the immersed boundary method to compute the fluid-structure interactions within the cochlea. It is a three-dimensional model based on an accurate cochlear geometry obtained from physical measurements. It inc...

Abstract. The Immersed Boundary Method (IBM) has been designed by Peskin for the modeling and the numerical approximation of fluid-structure interaction problems. Recently, a finite element version of the IBM as been developed, which offers interesting features for both the analysis of the problem under consideration and the robustness and flexibility of the numerical scheme. In this paper we s...

The objective of this work is to develop numerical tools useful for the understanding of fundamental phenomena in Blood Flow, including some biochemistry and cellular dynamics. An open problem that may benefit from multi-scale numerical tools is for example the understanding of the relation ship between inflammation and cholesterol plaque. The corresponding topics we address in this paper are (...