IEEE Transactions on Pattern Analysis and Machine Intelligence

Annual review of condensed matter physics

Journal of Statistical Mechanics: theory and experiment

Tables of integrals

Capillarity and Wetting Phenomena: Drops, Bubbles, Pearls, Waves

Granular material in a swirled container exhibits a curious transition as the number of particles is increased: At low densities, the particle cluster rotates in the same direction as the swirling motion of the container, while at high densities it rotates in the opposite direction. We investigate this phenomenon experimentally and numerically using a corotating reference frame in which the system reaches a statistical steady state. In this steady state, the particles form a cluster whose translational degrees of freedom are stationary, while the individual particles constantly circulate around the cluster's center of mass, similar to a ball rolling along the wall within a rotating drum. We show that the transition to counterrotation is friction dependent. At high particle densities, frictional effects result in geometric frustration, which prevents particles from cooperatively rolling and spinning. Consequently, the particle cluster rolls like a rigid body with no-slip conditions on the container wall, which necessarily counterrotates around its own axis. Numerical simulations verify that both wall-disk friction and disk-disk friction are critical for inducing counterrotation.

https://link.aps.org/accepted/10.1103/PhysRevE.100.012903

Geometric frustration induces the transition between rotation and counterrotation in swirled granular media

/pdf/sedimentation-dynamics-in-the-presence-of-polymer-1xfgc0zyt1.pdf

Sedimentation dynamics in the presence of polymer

Geometric imperfections are understood to play an essential part in the buckling of a thin shell, but how multiple defects interact to control the onset of failure remains unclear. Here, we examine the failure of real cylindrical shells by experimentally poking soda cans with a large imparted dimple. By high-speed imaging of the can’s surface, the initiation of buckling from axial loading is directly observed, revealing that larger dimples tend to set the initial buckling location. However, the influence of the shell’s background geometric imperfections can still occasionally dominate, causing initiation to occur far from the dimple. In this situation, probing at the dimple leads to an over-prediction of the axial capacity. Using finite-element simulations, we understand our experimental results as a competition between the large dimple and the shell’s inherent defect structure. In our simulations, we empirically observe a deformation-based criterion that connects the ideal poking location to the initiation site. This article is part of the theme issue ‘Probing and dynamics of shock sensitive shells’.

Hitting the mark: probing at the initiation site allows for accurate prediction of a thin shell’s buckling load

We report that an electro-osmotic instability of concentration enrichment in curved geometries for an aqueous electrolyte, as opposed to the well-known one, is initiated exclusively at the enriched interface (anode), rather than at the depleted one (cathode). For this instability, the limitation of unrealistically high material Peclet number in planar geometry is eliminated by the strong electric field arising from the line charge singularity. In a model setup of concentric circular electrodes, we show by stability analysis, numerical simulation, and experimental visualization that instability occurs at the inner anode, below a critical radius of curvature. The stability criterion is also formulated in terms of a critical electric field and extended to arbitrary (2d) geometries by conformal mapping. This discovery suggests that transport may be enhanced in processes limited by salt enrichment, such as reverse osmosis, by triggering this instability with needle-like electrodes.

Electro-osmotic Instability of Concentration Enrichment in Curved Geometries for an Aqueous Electrolyte

/pdf/high-speed-strain-measurements-surrounding-hydraulic-4f5feqxv4o.pdf

Shmuel M. Rubinstein

Papers

Geometric frustration induces the transition between rotation and counterrotation in swirled granular media

Sedimentation dynamics in the presence of polymer

Hitting the mark: probing at the initiation site allows for accurate prediction of a thin shell’s buckling load

Electro-osmotic Instability of Concentration Enrichment in Curved Geometries for an Aqueous Electrolyte

High Speed Strain Measurements Surrounding Hydraulic Fracture in Brittle Hydrogel