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Phase Diagram Characterization Using Magnetic Beads as Liquid Carriers
Published on: September 4, 2015
Size segregation in granular media induced by phase transition
M Tarzia1, A Fierro, M Nicodemi
1Dipartimento di Scienze Fisiche, Università degli Studi di Napoli Federico II, INFM and INFN, Italy.
Physical Review Letters
|October 4, 2005
Summary
A new thermodynamic theory explains size segregation in granular mixtures. Varying grain numbers causes a crossover from Brazil nut to reverse Brazil nut effects, a phase transition driven by depletion forces.
Area of Science:
- Physics
- Statistical Mechanics
- Materials Science
Background:
- Size segregation is a common phenomenon in granular mixtures.
- Understanding the underlying mechanisms is crucial for controlling granular flows.
Purpose of the Study:
- To analytically study size segregation in granular mixtures.
- To introduce a novel mean field theory based on statistical mechanics.
Main Methods:
- Application of a mean field theory to a lattice model of hard sphere binary mixtures under gravity.
- Investigation of the effects of varying small grain numbers and mass ratios.
- Confirmation through numerical simulations of 3D systems under taps.
Main Results:
- A new thermodynamic mechanism for size segregation was identified.
- A crossover from Brazil nut to reverse Brazil nut effect was observed.
- A phase transition was identified at a critical small grain number, attributed to depletion forces.
Conclusions:
- The developed mean field theory successfully explains size segregation.
- Depletion forces play a key role in inducing phase transitions in granular mixtures.
- Theoretical predictions are validated by numerical simulations.
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