Mechanism behind phase transitions in airplane boarding process

2016 ◽  
Vol 27 (06) ◽  
pp. 1650061 ◽  
Author(s):  
ShengJie Qiang ◽  
Bin Jia ◽  
QingXia Huang ◽  
ZiYou Gao

A simple airplane boarding model is built much like an asymmetric exclusion process (ASEP). The dynamics of the model is constrained by local interference between passengers and global seat assignments for individuals. We perform extensive Monte Carlo simulations by using a parallel update rule to determine quantities like boarding time and sequence correlation. Our results clarify the scaling behavior in boarding process and identify a critical value of arrival time interval for boarding time threshold. Three different phases (steady, intermediate and linear) with respect to the boarding time are distinguished and the mechanism behind phase transition is further discussed.

2008 ◽  
Vol 19 (06) ◽  
pp. 917-926 ◽  
Author(s):  
MARTA ZAWIERTA ◽  
WOJCIECH WAGA ◽  
DOROTA MACKIEWICZ ◽  
PRZEMYSŁAW BIECEK ◽  
STANISŁAW CEBRAT

Using Monte Carlo model of biological evolution it is discovered that populations can switch between two different strategies of their genomes' evolution: Darwinian purifying selection and complementing the haplotypes. The first one is exploited in the large panmictic populations while the second one in the small highly inbred populations. The choice depends on the crossover frequency. There is a power law relation between the critical value of crossover frequency and the size of panmictic population. Under constant inbreeding this critical value of crossover does not depend on the population size and has a character of phase transition. Close to this value sympatric speciation is observed.


2016 ◽  
Vol 113 (18) ◽  
pp. 4953-4957 ◽  
Author(s):  
Carlo Pierleoni ◽  
Miguel A. Morales ◽  
Giovanni Rillo ◽  
Markus Holzmann ◽  
David M. Ceperley

The phase diagram of high-pressure hydrogen is of great interest for fundamental research, planetary physics, and energy applications. A first-order phase transition in the fluid phase between a molecular insulating fluid and a monoatomic metallic fluid has been predicted. The existence and precise location of the transition line is relevant for planetary models. Recent experiments reported contrasting results about the location of the transition. Theoretical results based on density functional theory are also very scattered. We report highly accurate coupled electron–ion Monte Carlo calculations of this transition, finding results that lie between the two experimental predictions, close to that measured in diamond anvil cell experiments but at 25–30 GPa higher pressure. The transition along an isotherm is signaled by a discontinuity in the specific volume, a sudden dissociation of the molecules, a jump in electrical conductivity, and loss of electron localization.


2008 ◽  
Vol 15 (05) ◽  
pp. 605-612 ◽  
Author(s):  
VLADIMIR P. ZHDANOV

In the conventional Avrami–Kolmogorov–Johnson–Mehl model, the reaction or phase transition occurring in the 2D or 3D infinite medium is considered to start and proceed around randomly distributed and/or appearing nucleation centers. The radius of the regions transformed is assumed to linearly increase with time. The Monte Carlo simulations presented, illustrate what may happen if the transformation takes place in nanoparticles. The attention is focused on nucleation on the regular surface, edge and corner sites, and on the dependence of the activation energy for elementary reaction events on the local state of the sites.


2009 ◽  
Vol 87 (10) ◽  
pp. 1425-1435 ◽  
Author(s):  
Taunia L. L. Closson ◽  
Marc R. Roussel

When the anisotropy of a harmonic ion trap is increased, the ions eventually collapse into a two-dimensional structure consisting of concentric shells of ions. This collapse generally behaves like a second-order phase transition. A graph of the critical value of the anisotropy parameter vs. the number of ions displays substructure closely related to the inner-shell configurations of the clusters. The critical exponent for the order parameter of this phase transition (maximum extent in the z direction) was found computationally to have the value β = 1/2. A second critical exponent related to displacements perpendicular to the z axis was found to have the value δ = 1. Using these estimates of the critical exponents, we derive an equation that relates the amplitudes of the displacements of the ions parallel to the x–y plane to the amplitudes along the z axis during the flattening process.


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