When a spilled drop of coffee dries on a solid surface, it leaves a dense, ring-like deposit along the perimeter (Fig. 1a). The coffee—initially dispersed over the entire drop—becomes concentrated… Expand

The results provide a well-defined meaning for "random close packing" in terms of the fraction of all phase space with inherent structures that jam, and suggest that point J is a point of maximal disorder and may control behavior in its vicinity-perhaps even at the glass transition.Expand

Granular materials are ubiquitous in the world around us. They have properties that are different from those commonly associated with either solids, liquids, or gases. In this review the authors… Expand

Some solids - say, powdered raw materials in a conduit - often become jammed. Are the properties of such jammed solids different to those of ordinary solids? The answer 'yes' comes from a paper in… Expand

Numerical simulations of random packings of frictionless particles at T = 0.05 show that the distribution of threshold packing fractions narrows, and its peak approaches random close packing as the system size increases.Expand

The generation of analogies between the physics found in a simple sandpile and that found in complicated microscopic systems, such as flux motion in superconductors or spin glasses, has prompted a number of new theories and to a new era of experimentation on granular systems.Expand

The requirement of stability despite the destabilizing effect of pressure yields a lower bound on the number of extra contact per particle deltaz:deltaz> or =p1/2, which generalizes the Maxwell criterion for rigidity when pressure is present.Expand

In this model, the fluctuations in the force distribution arise because of variations in the contact angles and the constraints imposed by the force balance on each bead in the pile.Expand

When a system jams, it undergoes a transition from a flowing to a rigid state. Despite this important change in the dynamics, the internal structure of the system remains disordered in the solid as… Expand