Percolation

2017 ◽  
Author(s):  
Paul Charbonneau
Keyword(s):  
Phase Transitions ◽  
Water Vapor ◽  
Power Law ◽  
Critical Behavior ◽  
Scale Invariance ◽  
Granular Medium ◽  
Statistical Physics ◽  
Two Dimensions ◽  
Natural Systems ◽  
Fractal Clusters

This chapter explores a lattice-based system where complex structures can arise from pure randomness: percolation, typically described as the passage of liquid through a porous or granular medium. In its more abstract form, percolation is an exemplar of criticality, a concept in statistical physics related to phase transitions. A classic example of criticality is liquid water boiling into water vapor, or freezing into ice. The chapter first provides an overview of percolation in one and two dimensions before discussing the use of a tagging algorithm for identifying and sizing clusters. It then considers fractal clusters on a lattice at the percolation threshold, scale invariance of power-law behavior, and critical behavior of natural systems. The chapter includes exercises and further computational explorations, along with a suggested list of materials for further reading.

scholarly journals First-Order Structure Function Analysis of Statistical Scale Invariance in the AIRS-Observed Water Vapor Field

2012 ◽  
Vol 25 (16) ◽  
pp. 5538-5555 ◽  
Author(s):  
Kyle G. Pressel ◽  
William D. Collins
Keyword(s):  
Water Vapor ◽  
Structure Function ◽  
Power Law ◽  
Scale Invariance ◽  
Structure Functions ◽  
Scale Dependence ◽  
Global Maximum ◽  
Order Structure ◽  
Scaling Exponents ◽  
First Order

Abstract The power-law scale dependence, or scaling, of first-order structure functions of the tropospheric water vapor field between 58°S and 58°N is investigated using observations from the Atmospheric Infrared Sounder (AIRS). Power-law scale dependence of the first-order structure function would indicate that the water vapor field exhibits statistical scale invariance. Directional and directionally independent first-order structure functions are computed to assess the directional dependence of derived first-order structure function scaling exponents (H) for a range of scales from 50 to 500 km. In comparison to other methods of assessing statistical scale invariance, the methodology used here requires minimal assumptions regarding the homogeneity of the spatial distribution of data within regions of analysis. Additionally, the methodology facilitates the evaluation of anisotropy and quantifies the extent to which the structure functions exhibit scale invariance. The spatial and seasonal dependence of the computed scaling exponents are explored. Minimum scaling exponents at all levels are shown to occur proximate to the equator, while the global maximum is shown to occur in the middle troposphere near the tropical–subtropical margin of the winter hemisphere. From a detailed analysis of AIRS maritime scaling exponents, it is concluded that the AIRS observations suggest the existence of two scaling regimes in the extratropics. One of these regimes characterizes the statistical scale invariance the free troposphere with H approximately = 0.55 and a second that characterizes the statistical scale invariance of the boundary layer with H approximately = ⅓.

Statistical physics and phase transitions

2012 ◽  
pp. 12-42
Author(s):  
Lorenza Saitta ◽  
Attilio Giordana ◽  
Antoine Cornuejols
Keyword(s):  
Phase Transitions ◽  
Statistical Physics

Non-linear dynamics, chaos, complexity and enclaves in granitoid magmas

1996 ◽  
Vol 87 (1-2) ◽  
pp. 217-223 ◽  
Author(s):  
James Flinders ◽  
John D. Clemens
Keyword(s):  
Deterministic Chaos ◽  
Interfacial Area ◽  
Two Dimensions ◽  
Mixing Processes ◽  
Nd Isotope ◽  
Natural Systems ◽  
Non Linear ◽  
The Difference ◽  
Magma System ◽  
Isotope Systematics

ABSTRACT:Most natural systems display non-linear dynamic behaviour. This should be true for magma mingling and mixing processes, which may be chaotic. The equations that most nearly represent how a chaotic natural system behaves are insoluble, so modelling involves linearisation. The difference between the solution of the linearised and ‘true’ equation is assumed to be small because the discarded terms are assumed to be unimportant. This may be very misleading because the importance of such terms is both unknown and unknowable. Linearised equations are generally poor descriptors of nature and are incapable of either predicting or retrodicting the evolution of most natural systems. Viewed in two dimensions, the mixing of two or more visually contrasting fluids produces patterns by folding and stretching. This increases the interfacial area and reduces striation thickness. This provides visual analogues of the deterministic chaos within a dynamic magma system, in which an enclave magma is mingling and mixing with a host magma. Here, two initially adjacent enclave blobs may be driven arbitrarily and exponentially far apart, while undergoing independent (and possibly dissimilar) changes in their composition. Examples are given of the wildly different morphologies, chemical characteristics and Nd isotope systematics of microgranitoid enclaves within individual felsic magmas, and it is concluded that these contrasts represent different stages in the temporal evolution of a complex magma system driven by nonlinear dynamics. If this is true, there are major implications for the interpretation of the parts played by enclaves in the genesis and evolution of granitoid magmas.

Critical behavior of a two-lattice model of antiferromagnetic phase transitions

1975 ◽  
Vol 12 (11) ◽  
pp. 5034-5042 ◽  
Author(s):  
V. A. Alessandrini ◽  
H. J. de Vega ◽  
F. Schaposnik
Keyword(s):  
Phase Transitions ◽  
Critical Behavior ◽  
Lattice Model ◽  
Antiferromagnetic Phase

Critical behavior of La0.7Ca0.3Mn1−xNixO3 manganites exhibiting the crossover of first- and second-order phase transitions

2014 ◽  
Vol 184 ◽  
pp. 40-46 ◽  
Author(s):  
The-Long Phan ◽  
Q.T. Tran ◽  
P.Q. Thanh ◽  
P.D.H. Yen ◽  
T.D. Thanh ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Critical Behavior ◽  
Second Order

scholarly journals A PERCOLATION MODEL OF DIAGENESIS

2002 ◽  
Vol 13 (03) ◽  
pp. 319-331 ◽  
Author(s):  
S. S. MANNA ◽  
T. DATTA ◽  
R. KARMAKAR ◽  
S. TARAFDAR
Keyword(s):  
Numerical Simulation ◽  
Critical Behavior ◽  
Sedimentary Rocks ◽  
Two Dimensions ◽  
Percolation Model ◽  
Type Model ◽  
Stable Configuration ◽  
Critical Percolation ◽  
Restructuring Process ◽  
Simulation Results

The restructuring process of diagenesis in the sedimentary rocks is studied using a percolation type model. The cementation and dissolution processes are modeled by the culling of occupied sites in rarefied and growth of vacant sites in dense environments. Starting from sub-critical states of ordinary percolation the system evolves under the diagenetic rules to critical percolation configurations. Our numerical simulation results in two dimensions indicate that the stable configuration has the same critical behavior as the ordinary percolation.

Phase transitions in the six‐state vector Potts model in two dimensions

1984 ◽  
Vol 55 (6) ◽  
pp. 2429-2431 ◽  
Author(s):  
Challa S. S. Murty ◽  
D. P. Landau
Keyword(s):  
Phase Transitions ◽  
Potts Model ◽  
State Vector ◽  
Two Dimensions

A critical behavior of the Lennard–Jones dimeric fluid in two-dimensions.

2011 ◽  
Vol 605 (13-14) ◽  
pp. 1219-1223 ◽  
Author(s):  
W. Rżysko ◽  
M. Borówko
Keyword(s):  
Critical Behavior ◽  
Two Dimensions ◽  
Lennard Jones
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