This thesis approaches impact resistance in dense suspensions from a new perspective. The most well-known example of dense suspensions, a mixture of cornstarch and water, provides enough impact resistance to allow a person to run across its surface. In the past, this phenomenon had been linked to "shear thickening" under a steady shear state attributed to hydrodynamic interactions or granular dilation. However, neither explanation accounted for the stress scales required for a person to run on the surface. Through this research, it was discovered that the impact resistance is due to local compression of the particle matrix. This compression forces the suspension across the jamming transition and precipitates a rapidly growing solid mass. This growing solid, as a result, absorbs the impact energy. This is the first observation of such jamming front, linking nonlinear suspension dynamics in a new way to the jamming phase transition known from dry granular materials.

Powders have been studied extensively because they arise in a wide variety of fields, ranging from soil mechanics to manufacture of pharmaceuticals. Only recently, however, with the deepening understanding of fractals, chaos, 1/f noise, and self-organization, has it been useful to study the mechanical properties of powders from a fundamental physical perspective. This book collects articles by some of the foremost researchers in the field, including chapters on: the role of entropy in the specification of a powder, by S.F. Edwards (Cambridge); discrete mechanics, by P.K. Haff (Duke); computer simulations of granular materials, by G.C. Barker (Norwich); pattern formation and complexity in granular flow, by R.P. Behringer and G.W. Baxter (Duke); avalanches in real sand piles, by A. Mehta (Birmingham); micromechanical models of failure, by M.J. Adams (Unilever) and B.J. Briscoe (Imperial College); mixing and segregation in particle flows, by J. Bridgwater (Birmingham); and hard-sphere colloidal suspensions, by P. Bartlett (Bristol) and W. van Megen (Melbourne).

2007 account of developments in granular physics for researchers in statistical and mathematical physics.

Granular systems arise in a variety of geological and industrial settings, from landslides, avalanches, and erosion to agricultural grains and pharmaceutical powders. Understanding the underlying physics that governs their behavior is the key to developing effective handling and transport mechanisms as well as appropriate environmental policies.Han

Provides the state-of-the-art of the physics of granular media for graduate students and researchers in physics, applied mathematics and engineering.

1. Introduction. 1.1. The significance of wet granular matter. 1.2. Energy scales. 1.3. Typical questions to be asked. 1.4. How we shall proceed -- 2. Grains and granular fluids. 2.1. Grains. 2.2. Granular fluids. 2.3. Conclusions -- 3. Wetting. 3.1. Planar substrates. 3.2. Rough substrates. 3.3. Conclusions -- 4. Capillary forces. 4.1. Capillary bridge between flat walls. 4.2. Capillary bridge between spherical bodies. 4.3. Capillary bridge between irregular grains. 4.4. Force networks. 4.5. Conclusions -- 5. Wet granular gases. 5.1. Dynamical aspects of capillary bridges. 5.2. Free cooling and clustering. 5.3. Liquid-gas coexistence. 5.4. Collective phenomena far from thermal equilibrium. 5.5. Conclusions -- 6. Wet granular piles. 6.1. Geometrical aspects of granular piles. 6.2. Regimes of wetness. 6.3. Mechanical properties of wet granular piles. 6.4. Phase transitions in wet granular piles. 6.5. Conclusions -- 7. Special topics. 7.1. The physics of sand castles. 7.2. Immiscible granular suspensions. 7.3. Quicksand and quickclay