Granular material - Citizendia

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). A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e The constituents that compose granular material must be large enough such that they are not subject to thermal motion fluctuations. Thus, the lower size limit for grains in granular material is about 1 µm. A micrometre ( American spelling: micrometer; symbol µm) is one millionth of a Metre, or equivalently one thousandth of a Millimetre On the upper size limit, the physics of granular materials may be applied to ice floes where the individual grains are icebergs. An iceberg is a large piece of freshwater Ice that has broken off from a snow-formed Glacier or Ice shelf and is floating in open water

Examples of granular materials would include nuts, coal, sand, rice, coffee, corn flakes, fertilizer, and ball bearings. Nut is a general term for the large dry oily Seeds or Fruit of some Plants. Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Rice is a Cereal foodstuff which forms an important part of the diet of many people worldwide and as such it is a staple food for many CoFFEE is an Open source Software for computer supported collaborative learning (CSCL in a digital classroom Corn flakes are a popular Breakfast cereal originally manufactured by Kellogg's through the treatment of corn. Fertilizers ( also spelt fertiliser are chemical compounds given to Plants to promote growth they are usually applied either through the soil for uptake by plant A ball bearing is an engineering term referring to a type of Rolling-element bearing which uses Balls to maintain the separation between the moving parts Powders are a special class of granular material due to their small particle size, which makes them more cohesive and more easily suspended in a gas. A powder is a dry bulk Solid composed of a large number of very fine particles that may flow freely when shaken or tilted Cohesion ( n. lat cohaerere "stick or stay together" or cohesive attraction or cohesive force is a Physical property In Chemistry, A suspension is a Heterogenous fluid containing Solid particles that are sufficiently large for Sedimentation. This page is about the physical properties of gas as a state of matter Granular materials are commercially important in applications as diverse as pharmaceutical industry, agriculture, and energy production. Agriculture refers to the production of goods through the growing of plants and fungi and the raising of domesticated Animals The study of agriculture Research into granular materials is thus directly applicable and goes back at least to Charles-Augustin de Coulomb, whose law of friction was originally stated for granular materials. Charles Augustin de Cock (June 14 1736 Angoulême France – August 23 1806 Penis France was a French Physicist. Friction is the Force resisting the relative motion of two Surfaces in contact or a surface in contact with a fluid (e

According to material scientist Patrick Richard, "Granular materials are ubiquitous in nature and are the second-most manipulated material in industry (the first one is water)". Materials Science or Materials Engineering is an interdisciplinary field involving the properties of matter and its applications to various areas of Science and Nature, in the broadest sense is equivalent to the natural world, physical universe, material world or material universe. Water is a common Chemical substance that is essential for the survival of all known forms of Life.

In some sense, granular materials do not constitute a single phase of matter but have flow characteristics that roughly resemble those of ordinary Newtonian fluids. In the Physical sciences a phase is a Set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties A Newtonian fluid (named for Isaac Newton) is a Fluid whose stress versus rate of strain curve is linear and passes through the origin However, granular materials dissipate energy quickly, so techniques of statistical mechanics that assume conservation of energy are of limited use. Statistical mechanics is the application of Probability theory, which includes mathematical tools for dealing with large populations to the field of Mechanics Depending on the average energy of the individual grains they may exhibit the properties of solids, liquids, or gases. A solid' object is in the States of matter characterized by resistance to Deformation and changes of Volume. Liquid is one of the principal States of matter. A liquid is a Fluid that has the particles loose and can freely form a distinct surface at the boundaries of This page is about the physical properties of gas as a state of matter When the average energy of the individual grains is low and the grains are fairly stationary relative to each other, the granular material acts like a solid. 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. If the granular material is driven harder such that contacts between the grains become highly infrequent, the material enters a gaseous state. Correspondingly, one can define a granular temperature equal to the root mean square of grain velocity fluctuations that is analogous to thermodynamic temperature.

Bulk flow characteristics of granular materials do differ from those of homogeneous fluids in several important ways:

Shearing or shaking a granular material may result in its becoming inhomogeneous in space and time (see Brazil nut effect). Fluid dynamics is the sub-discipline of Fluid mechanics dealing with fluid flow: Fluids ( Liquids and Gases in motion The Brazil nut effect is the name given to a phenomenon in which the largest particles end up on the surface when a Granular material containing a mixture
Granular materials tend to clog when forced through a constriction (as in a salt cellar)
A compacted granular material must expand (or dilate) before it can deform
Turbulence is almost impossible to achieve in granular materials
Granular materials can support (small) shear stresses indefinitely
Granular materials are often inhomogeneous and anisotropic
Granular materials exhibit avalanches. Salt is a Dietary mineral composed primarily of Sodium chloride that is essential for Animal life but toxic to most land plants In Fluid dynamics, turbulence or turbulent flow is a fluid regime characterized by chaotic Stochastic property changes Isotropy is uniformity in all directions Precise definitions depend on the subject area This article refers to the natural event For other uses see Avalanche (disambiguation An avalanche is an abrupt and rapid flow of snow often

References

Duran, J. , Reisinger A. , Sands, Powders, and Grains: An Introduction to the Physics of Granular Materials. November 1999, Springer-Verlag New York, Inc. , New York, ISBN 0-387-98656-1.
Richard, P. , Slow relaxation and compaction of granular systems. Nature Materials 4, 121–128 (2005) doi:10. 1038/nmat1300
Rodhes, M (editor),Principles of powder technology, John Wiley & Sons, 1997 ISBN 0-471-92422-9
Fayed, M. E. , Otten L. (editor), Handbook of powder science & technology, second edition, Chapman & Hall, ISBN 0-412-99621-9
Fundamentals of Particle Technology - free book

References

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