5,992 research outputs found
Asymmetric simple exclusion process in one-dimensional chains with long-range links
We study the boundary-driven asymmetric simple exclusion process (ASEP) in a
one-dimensional chain with long-range links. Shortcuts are added to a chain by
connecting different pairs of sites selected randomly where and
denote the chain length and the shortcut density, respectively. Particles flow
into a chain at one boundary at rate and out of a chain at the other
boundary at rate , while they hop inside a chain via nearest-neighbor
bonds and long-range shortcuts. Without shortcuts, the model reduces to the
boundary-driven ASEP in a one-dimensional chain which displays the low density,
high density, and maximal current phases. Shortcuts lead to a drastic change.
Numerical simulation studies suggest that there emerge three phases; an empty
phase with , a jammed phase with , and a shock phase
with where is the mean particle density. The shock phase is
characterized with a phase separation between an empty region and a jammed
region with a localized shock between them. The mechanism for the shock
formation and the non-equilibrium phase transition is explained by an analytic
theory based on a mean-field approximation and an annealed approximation.Comment: revised version (16 pages and 6 eps figures
Condensation transition in a model with attractive particles and non-local hops
We study a one dimensional nonequilibrium lattice model with competing
features of particle attraction and non-local hops. The system is similar to a
zero range process (ZRP) with attractive particles but the particles can make
both local and non-local hops. The length of the non-local hop is dependent on
the occupancy of the chosen site and its probability is given by the parameter
. Our numerical results show that the system undergoes a phase transition
from a condensate phase to a homogeneous density phase as is increased
beyond a critical value . A mean-field approximation does not predict a
phase transition and describes only the condensate phase. We provide heuristic
arguments for understanding the numerical results.Comment: 11 Pages, 6 Figures. Published in Journal of Statistical Mechanics:
Theory and Experimen
Experimental measurements of scale adhesion for a pre-oxidized steel charge
In industrial practice, the charge is heated before the forming process and often reaches the furnace “cold”. This means that after leaving the continuous casting of steel, for various reasons it is not heated immediately, but stored instead. This causes not only the cooling of the charge but also its oxidation in the atmosphere of the surrounding air. The paper presents the research methodology and discusses the results of adhesion measurements for a preoxidized steel charge
Experimental measurements of scale adhesion for a pre-oxidized steel charge
In industrial practice, the charge is heated before the forming process and often reaches the furnace “cold”. This means that after leaving the continuous casting of steel, for various reasons it is not heated immediately, but stored instead. This causes not only the cooling of the charge but also its oxidation in the atmosphere of the surrounding air. The paper presents the research methodology and discusses the results of adhesion measurements for a preoxidized steel charge
New exact fronts for the nonlinear diffusion equation with quintic nonlinearities
We consider travelling wave solutions of the reaction diffusion equation with
quintic nonlinearities . If the parameters
and obey a special relation, then the criterion for the existence of a
strong heteroclinic connection can be expressed in terms of two of these
parameters. If an additional restriction is imposed, explicit front solutions
can be obtained. The approach used can be extended to polynomials whose highest
degree is odd.Comment: Revtex, 5 page
Physics with the ALICE experiment
ALICE experiment at LHC collects data in pp collisions at =0.9,
2.76 and 7 TeV and in PbPb collisions at 2.76 TeV. Highlights of the detector
performance and an overview of experimental results measured with ALICE in pp
and AA collisions are presented in this paper. Physics with proton-proton
collisions is focused on hadron spectroscopy at low and moderate .
Measurements with lead-lead collisions are shown in comparison with those in pp
collisions, and the properties of hot quark matter are discussed.Comment: Presented at the Conference of the Nuclear Physics Division of the
Russian Academy of Science, 11-25.11.2011, ITEP, Moscow. 16 pages, 14 figure
Clonal interference and Muller's ratchet in spatial habitats
Competition between independently arising beneficial mutations is enhanced in
spatial populations due to the linear rather than exponential growth of clones.
Recent theoretical studies have pointed out that the resulting fitness dynamics
is analogous to a surface growth process, where new layers nucleate and spread
stochastically, leading to the build up of scale-invariant roughness. This
scenario differs qualitatively from the standard view of adaptation in that the
speed of adaptation becomes independent of population size while the fitness
variance does not. Here we exploit recent progress in the understanding of
surface growth processes to obtain precise predictions for the universal,
non-Gaussian shape of the fitness distribution for one-dimensional habitats,
which are verified by simulations. When the mutations are deleterious rather
than beneficial the problem becomes a spatial version of Muller's ratchet. In
contrast to the case of well-mixed populations, the rate of fitness decline
remains finite even in the limit of an infinite habitat, provided the ratio
between the deleterious mutation rate and the square of the
(negative) selection coefficient is sufficiently large. Using again an analogy
to surface growth models we show that the transition between the stationary and
the moving state of the ratchet is governed by directed percolation
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