We have performed a systematic, large-scale simulation study of granular media in two and three dimensions, investigating the rheology cohesionless particles inclined plane geometries, i.e., chute flows. find that over wide range parameter space interaction coefficients inclination angles, steady-state flow regime exists which energy input from gravity balances dissipated friction inelastic collisions. In this regime, bulk packing fraction (away top free surface bottom plate boundary)...

Suspensions of polarizable particles in nonpolarizable solvents form fibrillated structures strong electric fields. The resulting increase viscosity these "electrorheological" fluids can couple electrical to hydraulic components a servomechanism. physical properties are unusual owing the long-range, anisotropic nature interparticle forces. Immediately after field is applied, elongated chains or columns parallel field. This structure then coarsens as result thermal forces between columns. In...

We analyze numerical studies of the harmonic measure diffusion-limited aggregates in two dimensions by modeling this a fractal set singularities. discuss relationship between dimension and strength singularities, implications these ideas both for entire aggregate also more complete theory aggregation.

Electrorheological (ER) fluids are colloidal suspensions of highly polarizable particles in a nonpolarizable solvent. In strong electric field, the behavior fluid is dominated by dipolar interactions between particles. We address problems structure formation and long-time relaxation an ER fluid. When high field applied to fluid, dielectric columns oriented parallel rapidly form. The these much slower process. calculate shape formed time scale for columnar structure.

We study static packings of frictionless and frictional spheres in three dimensions, obtained via molecular dynamics simulations, which we vary particle hardness, friction coefficient, coefficient restitution. Although hard-spheres are always isostatic (with six contacts) regardless construction history restitution achieve a multitude hyperstatic that depend on system parameters history. Instead immediately dropping to four, the coordination number reduces smoothly from $z=6$ as $\mu$...

Capillary forces significantly affect the stability of sandpiles. We analyze sandpiles with such forces, and find that critical angle is unchanged in limit an infinitely large system; however, this increased for finite-sized systems. The failure occurs bulk sandpile rather than at surface. This related to a standard result soil mechanics. increase determined by surface roughness particles, exhibits three regimes as function added-fluid volume. Our theory qualitative agreement recent...

Josephson-junction arrays in transverse magnetic fields are most simply described by uniformly frustrated XY models. Frustration these models is parametrized f, the ratio of flux through one cell array to quantum. We propose a quasi-one-dimensional structure for ground states models, valid (1/3)\ensuremath{\le}f\ensuremath{\le}(1/2). The energies and zero-temperature critical currents this can be calculated exactly. For rational f=p/q, functions q only; irrational they independent f....

Nature confronts us at every turn with patterns—whether the stately spiral shapes of galaxies and hurricanes or beautiful symmetries snowflakes silicon. A host processes can play a role in forming natural patterns, though they usually involve an interaction between transport thermodynamic properties matter radiation involved.

We present experimental and theoretical results on the shear thinning of electrorheological fluids. Rheological measurements a model fluid consisting monodisperse silica spheres immersed in dielectric liquid show power-law dependence \ensuremath{\mu}\ensuremath{\propto}\ensuremath{\gamma}${\mathrm{\ifmmode \dot{}\else \.{}\fi{}}}^{\mathrm{\ensuremath{-}}\mathrm{\ensuremath{\Delta}}}$ apparent viscosity \ensuremath{\mu} strain rate \ensuremath{\gamma}\ifmmode \.{}\fi{}, with...

We report a real-time, two-dimensional light scattering study of the evolution structure in concentrated electrorheological fluid during ``liquid-solid'' phase transition. find that after particle chaining along electric field lines, strong lobes appear at finite wave vector q orthogonal to and then brighten as they move q=0. This indicates existence an unstable concentration fluctuation signifies segregation chains into columns. suggest theoretical explanation for our results.

The ground states of both the fully frustrated XY model in two dimensions and 3He-A films have Z2*U(1) symmetries. Both line defects (domain walls) point (vortices) can disrupt ordering these systems at finite temperatures. presence induces a breakdown on vortex charge quantisation systems. In square lattice, integral is replaced by quarter-integral quantisation; 3He-A, completely destroyed. It follows that phase cannot coexist with Z2 disorder. relevant to Josephson junction arrays...

We have used two-dimensional light scattering to study the structure and dynamics of a single-scattering electrorheological fluid in quiescent state steady oscillatory shear. Studies show that particle columns grow two stages. Particles first chain along electric field, causing lobes appear orthogonal then aggregate into columns, move smaller angles. Column formation can be understood terms thermal coarsening model we present, whereas early-time direction parallel field compared theory line...

An extended Flory−Rehner and Regular Solution Theory model framework has been developed for interpreting the swelling behavior of kerogen toward solvents. Thermodynamic parameters controlling response are solubility parameter, cross-link density, volume fraction network veq that minimizes its elastic strain energy, termed "native swelling". These obtained by optimizing match between theoretical predictions experimental data neat A good theory experiment is Draupne Type II kerogen. results...

A model is used to show that a Josephson-junction array in an irrational magnetic field undergoes glass transition for finite cooling rate. At zero temperature the resultant glassy state possesses nonzero critical current. The low-temperature behavior of system can be modeled by spin-wave theory. relevance these results real experiments on arrays discussed.

We argue that inelastic grains in a flow under gravitation tend to collapse into states which the relative normal velocities of two neighboring is zero. If time scale for this gravitational shorter than inverse strain rates flow, we propose will lead formation "granular eddies", large-scale condensed structures particles moving coherently with one another. The these eddies determined by gradient rate. Applying concepts chute granular media (gravitationally driven down inclined planes),...

Based on large-scale, three-dimensional chute flow simulations of granular systems, we uncover strong analogies between the jamming grains and liquid-glass transition. The angle inclination $\ensuremath{\theta}$ in former transition appears as an analog temperature T latter. is manifested development a plateau contact normal force distribution $P(f)$ at small forces, splitting second peak pair-correlation function $g(r),$ increased fluctuations system energy. static state also exhibits...

We measure the increase in maximum stable angle of a sandpile, theta(c), with volume fraction, phi liquid added to cause cohesion between grains. For two different liquids, tan theta(c) does not apparently scale air-liquid surface tension at low phi, whereas it higher phi. This suggests that forms menisci asperities on surfaces grains before filling cohesive intergrain contact points. In this limit, theta(c)(phi) agrees roughness theory. Electron and fluorescence microscopy dry wet support model.

We report numerical results for velocity correlations in dense, gravity-driven granular flow down an inclined plane. For the grains on surface layer, our are consistent with experimental measurements reported by Pouliquen. show that correlation structure within planes parallel to persists bulk. The two-point function exhibits exponential decay small intermediate values of separation between spheres. lengths identified fits data nontrivial dependence averaging time...

We present a general theoretical framework for understanding the geometrical frequency dependence of impedance ionic solutions in contact with rough or irregular metallic electrodes. In two dimensions all relevant information regarding surface is contained conformal transformation that maps onto straight line. The ``constant-phase-angle'' related to scaling current inhomogeneities within two-scale model structure surface. capacitive effects this are controlled by generalization ``Parisi matrix.''

Introduction: Physics in the World of General Molecules. What Does a Polymer Molecule Look Like? Polymers are Long Molecular Chains. Flexibility Mechanisms. A Portrait Chain. Heteropolymers, Branched and Charged Macromolecules. Ring Macromolecules Topological Effects. How Made? Kinds Substances There? Traditional States Matter Polymers. Possible Substances. Plastics. Polymeric Fibres. Liquid Crystals Superstrong Solutions. Blends Block-Copolymers. Ionomers Associating Nature: Few Words About...