Factbites
 Where results make sense
About us   |   Why use us?   |   Reviews   |   PR   |   Contact us  

Topic: Granular matter


Related Topics

In the News (Wed 1 Oct 14)

  
  Granular material - Wikipedia, the free encyclopedia
A granular material is a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact (the most common example would be friction when grains collide).
On the upper size limit, the physics of granular materials may be applied to ice floes where the individual grains are icebergs.
When the granular matter is driven and energy is fed into the system (such as by shaking) such that the grains are not in constant contact with each other, the granular material is said to fluidize and enter a liquid-like state.
en.wikipedia.org /wiki/Granular_material   (554 words)

  
 research granular matter
Sand, salt, sugar, and granular matter in general, present quite interesting behaviour, because depending on the external forces they can be likened to a solid (compacted grains do not lose their shape), a liquid (they can flow) or a gas (in fact, a "granular temperature" can be defined for diluted, shaken granular matter).
Granular matter can be considered as a many-particle system, its main feature being that collisions among grains are dissipative.
We study "dry" granular matter, meaning that the material is non cohesive: the only relevant forces are the inertial ones plus the external fields, such as gravity.
fisica.unav.es /~angel/gran/research.html   (1182 words)

  
 Granular Media
The theoretical description and the understanding of the basic phenomena in granular matter is however not yet satisfactory.
Granular matter consists of macroscopic particles of different size, shape, and surface roughness, leading to specific packing behavior: disordered structures allow compaction only in connection with reorganization of parts of the system.
A part of the research on dry granular materials at the ICA 1 was performed in connection with the SFB 382, project A6 ``Schnelle Algorithmen zur Simulation diskreter Teilchen'' which granted one scholarship.
www.ica1.uni-stuttgart.de /Jahresberichte/98/node10.html   (327 words)

  
 Granular Materials
Granular flows are classically divided in two regimes depending on the kind of interactions experienced by the particles : a rapid regime where collisions are important, and a dense regime where multi particles interactions exist and friction is important.
Granular Flow down a Rough Incline Plan A brief overview of the simulation studies of gravity-driven, dense granular flows is given.
The theory captures the range of inclination angles at which steady, fully-developed flows are observed, the corresponding shape of the mean and fluctuation velocity profiles, the dependence of the flow rate on inclination, flow height, interparticle friction and normal restitution coefficient, and the dependence of the height of basal flows on inclination.
cnls.lanl.gov /People/ebn/gfk/abstract.html   (4033 words)

  
 An Overview of Granular Theories
are respectively the volumetric granular concentration and the density of the grains.
For a "typical" granular matter, "e" is taken between 0.9 and 0.99.
They serve as correction functions for the granular shear viscosity and the conductivity of the granular temperature because the collision between grains is an inelastic phenomenon and because grains have a non-zero volume.
www.angelfire.com /extreme/volcano/granular_theory.html   (3648 words)

  
 Research: Granular materials
Size segregation is a widely observed consequence of sheared flow in granular media, in which the larger grains rise to the upper surface of the bulk, despite the fact that all grains have the same material density.
The problems discussed are granular flow from a silo, the size-grading that occurs in inclined-chute flow, and the surface waves that appear in a thin, vertically vibrated layer.
Molecular (or granular) dynamics methods are used to study the gravity-driven flow of granular material through a horizontal aperture in three dimensions.
www.ph.biu.ac.il /~rapaport/research/granular.html   (1312 words)

  
 From Gases to Glasses in Granular matter   (Site not responding. Last check: 2007-10-12)
Granular materials play a vital role in many industrial sectors including pharmaceutical, chemical, food and agricultural, plastic, ceramic and metal manufacturing, mineral processing, construction and civil engineering.
The collective behavior of an assembly of granular particles is, due to the dissipative nature of the interparticle forces, very different from that of molecular systems.
Granular compaction requires a more phenomenological approach, and researchers often try to exploit the connection with glasses.
www.lptl.jussieu.fr /CECAM2005/presentation.html   (251 words)

  
 Sand Land
A fascinating property of binary mixtures of granular media is their tendancy to segregate when shaken, rotated or poured.
Research at the University of Minnesota's granular material laboratory focuses on two unique, self-segregating phenomena: axial segregation of rotated mixtures of glass beads and avalanche stratification of poured mixtures of sand and sugar.
Segregation of granular materials is a significant problem for particle processing industries such as pharmaceutical and agricultural firms.
groups.physics.umn.edu /sand   (319 words)

  
 Lorentz Center - Cooperative Grains: From Granular Matter to Nano Materials   (Site not responding. Last check: 2007-10-12)
The major goal of this workshop is to bring together researchers from the disparate fields of granular matter research and nano-sciences.
The technological importance of granular matter as well as the new perspectives offered by nano science have led to unique and lively research efforts across the disciplines.
In granular matter, although having been a well established research field for decades, still very basic questions wait for an answer.
www.lc.leidenuniv.nl /lc/web/2003/82/description.php3?wsid=82   (537 words)

  
 Evgeniy Khain - Research Interests
Driven granular matter (matter composed of macroscopic particles interacting dissipatively) is another fascinating example of intrinsically non-equilibrium systems.
Another instability is the thermal granular convection that develops in the same prototypical system, but in the presence of gravity [Refs.
Understanding the analogous instability in a granular fluid is important for the physics of granular matter.
www-personal.umich.edu /~ekhain/research.html   (1420 words)

  
 Physics of Granular Materials
Granular materials when poured or shaken display a surprising range of collective behavior such as convection, size separation and pattern formation.
We investigated the effect of anisotropy of the constituent particles on the packing and dynamics of granular matter.
We examined the gravity driven flow of granular materials inside a silo in collaboration with M.
physics.clarku.edu /~akudrolli/granular.html   (1086 words)

  
 What is a granular medium?   (Site not responding. Last check: 2007-10-12)
Indeed, the gas phase is always there, even in highly concentrated granular flows … therefore, for granular flows found in Nature, we must always have a continuum between highly concentrated flow (where the dispersed phase dominates) to highly diluted flow (where the gas phase dominates).
If we consider the two end-members of granular flows, highly concentrated to highly diluted, it should be possible to define in meaningful ways the constitutive equations of such end-member flows along with equations to connect those end-member rheologies.
Of course, if the granular concentration gets so high and close to the maximum limit allowed for a randomly packed structure (64%), the grains will not be allowed to randomly move, and therefore, the granular temperature will tend to zero.
www.granular-volcano-group.org /granular_medium.html   (4263 words)

  
 Granular Matter Homepage.   (Site not responding. Last check: 2007-10-12)
The key feature of a granular gas (making it fundamentally different from any standard gas) is its tendency to spontaneously separate into dense and dilute regions.
For sufficiently high impact velocity, air is entrained by the collapsing void, forming an air bubble in the sand.
This bubble slowly rises to the surface, and upon reaching it causes a granular eruption.
stilton.tnw.utwente.nl /people/rene/Granular.html   (323 words)

  
 Condensed matter physics - Wikipedia, the free encyclopedia
Condensed matter physics is the field of physics that deals with the macroscopic physical properties of matter.
Historically, condensed matter physics grew out of solid-state physics, which is now considered one of its main subfields.
The term "condensed matter physics" was apparently coined by Philip Anderson when he renamed his research group - previously "solid-state theory" - in 1967.
en.wikipedia.org /wiki/Condensed_matter   (438 words)

  
 Granular Dynamics - UNIMAT - University of Nottingham   (Site not responding. Last check: 2007-10-12)
Granular materials are extremely unusual in that they can simultaneously display properties normally associated with solids, liquids and gases, together with other properties which are uniquely their own.
However despite studies by scientists as respected as Faraday through to a recent flurry of activity in the physics community, many of these properties are still poorly understood.
The inelastic collisions of granular systems leads to a wealth of relevant new phenomena, and the gas surrounding the particles is important in some circumstances.
www.nottingham.ac.uk /unimat/expertise/modelling/granular.phtml   (253 words)

  
 Granular Matter   (Site not responding. Last check: 2007-10-12)
Granular materials are a field of growing physical interest.
They are also very important from the technological and industrial point of view: many materials in industrial processes are granular (think of sand, wheat, flour, soil, coal, seeds, pills,...).
If you like to know more about granular materials, see our publication list or visit a page with various links to granular media.
www.comphys.uni-duisburg.de /GranMat.html   (207 words)

  
 Granular Matter   (Site not responding. Last check: 2007-10-12)
Granular materials are everywhere; they are central in a very wide range of domains from agriculture to pharmaceutical industry.
Granular materials can flow like liquids in some circumstances but they can act like solids in others.
In this forum, studies and methodologies concerning the science of granular matter and other related complex materials such as foams, porous media and cellular solids, will be presented and discussed.
wwwrsphysse.anu.edu.au /granularmatter/info.php   (357 words)

  
 The Complex Matter and Nonlinear Physics Laboratory
Using a novel fluoroscent index matching technique, we show that the fluctuations in granular flows are remarkably similar to that observed in a dense liquids.
Friction of a slider on a granular layer: Nonmonotonic thickness dependence and effect of boundary conditions
Particle shape is observed to have a strong impact on the dynamics of granular materials.
physics.clarku.edu /~akudrolli/nls.html   (146 words)

  
 RedOrbit - Science - Temperature Key to Avalanche Movement
Mayor and his colleagues, Gianfranco D'Anna, Alain Barrat, Vittorio Loreto, have shown that shaken granular matter behaves in a way related to Einstein's theory of Brownian motion, first published in 1905.
Mayor and his colleagues have now devised a thermometer that can measure the temperature of a granular material based on the degree of agitation of its component particles.
Being able to measure "temperature" might allow researchers to better understand the peculiar properties of a granular material, which is of crucial importance to industries that handle powders and particulate materials from pharmaceutical pills and food powders to sand and cement in the construction industry.
www.redorbit.com /news/display/?id=123796   (443 words)

  
 ScienceDaily: Physicists Discover Temperature Key To Avalanche Movement   (Site not responding. Last check: 2007-10-12)
Being able to measure "granular temperature" might allow researchers to better understand the peculiar properties of a granular material, which is of crucial importance to industries that handle powders and particulate materials from pharmaceutical pills and food powders to sand and cement in the construction industry.
Phase (matter) -- A phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i.e.
Avalanche -- An avalanche is a slide of a large snow (or rock) mass down a mountainside, caused when a buildup of snow is released down a slope, and is one of the major dangers faced in the mountains in...
www.sciencedaily.com /releases/2005/01/050131224844.htm   (1817 words)

  
 Hernán Makse's Home Page
More specifically, we try to focus on the study of jammed matter, spanning from colloidal suspensions, dense emulsions to granular materials and glasses in search of unifying theoretical frameworks.
Current research on thermodynamics of jamming: Simulations and experiments are being performed to investigate the statistical mechanics of jammed particulate matter.
Granular Dynamics in Compaction and Stress Relaxation (experiments and theory).
lisgi1.engr.ccny.cuny.edu /~makse   (715 words)

  
 Experimental Condensed Matter Physics
An example is the transition from solid- to liquid-like behavior at the onset of particle flow and avalanching down the slope of a sandpile.
Our current research investigates consequences of the inherently inhomogeneous force distributions inside granular matter, the glassy settling behavior as the system explores phase space, spontaneous structure formation and dynamic instabilities under applied stresses, and the propagation of energy and momentum through these highly dissipative materials.
Examples of poorly understood classical physics include the anomalous flow of granular material, the long messy tendrils left by honey spooned from one dish to another, the pesky rings deposited by spilled coffee on a table after the liquid evaporates or the common splash of a drop of liquid onto a countertop.
physics.uchicago.edu /x_cond.html   (3181 words)

  
 Observing brownian motion in vibration-fluidized granular matter : Nature   (Site not responding. Last check: 2007-10-12)
The vibro-fluidized granular medium is a driven environment, with continuous injection and dissipation of energy, and the immersed oscillator can be seen as analogous to an elastically bound brownian particle.
This gives experimental access to a granular viscosity and an effective temperature; however, these quantities are anisotropic and inhomogeneous.
Surprisingly, the vibro-fluidized granular matter behaves as a 'thermal' bath satisfying a fluctuation-dissipation relation.
www.nature.com /doifinder/10.1038/nature01867   (331 words)

  
 Granular Volcano Group - Welcome Page   (Site not responding. Last check: 2007-10-12)
This includes: (i) computer modeling of granular gravity current flows, (ii) rheology of the granular-matter, (iii) grain-size analysis of pyroclastic flows commonly seen in volcanology (can we relate grain-size properties of a set of grains to the physical processes that have formed, moved and settled them), (iv) explain fluid-dynamic concepts in simple but accurate ways;
2- Volcanology and granular-sciences must be fun and for everyone, no matter what your scientific background is! So, theoretical research should not rhymed with "secret and highly-classified research" as it should be accessed by whomever is interested in granular-flows in geophysics and volcanology.
The details of granular flow get hairy because the fluid and the particles are in different phases, so the equation-laden site is not for the math-phobic or physics-averse.
www.granular-volcano-group.org /wlc.html   (1192 words)

  
 Granular matter
Jamming during the discharge of granular matter from a silo
Size segregation of granular matter in silo discharges
Testing the thermodynamic approach to granular matter with a numerical model of a decisive experiment
www.fzu.cz /~slanina/bookmark_files/bkm9.html   (3254 words)

  
 Complex Systems and Nonlinear Dynamics in Fluids and Granular Materials - Publications
"Surface Roughness Effects in Granular Matter: Influence on Angle of Repose and the Absence of Segregation," N. Pohlman, B.L. Severson, J.M. Ottino, and R.M. Lueptow, Phys.
An Experimental Study of the Flowing Granular Layer in a Rotating Tumbler," N. Jain, J.M. Ottino, and R.M. Lueptow, Phys.
"Radial Segregation of Granular Mixtures in Rotating Cylinders," D.V. Khakhar, J.J. McCarthy, and J.M. Ottino, Phys.
mixing.chem-eng.northwestern.edu /publications.html   (1496 words)

  
 Craters in a Sandbox
Two teams have discovered that balls dropped into sand and other granular matter form craters remarkably similar to those on the moon.
But the materials didn't matter much; the depth was mainly affected by the density and diameter of the ball and the height from which it was dropped.
Their crater diameters followed the "energy to the 1/4 power" rule of thumb, but the depth didn't depend on energy in a simple way.
focus.aps.org /story/v12/st8   (773 words)

Try your search on: Qwika (all wikis)

Factbites
  About us   |   Why use us?   |   Reviews   |   Press   |   Contact us  
Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.