358 research outputs found
Scaling behavior of the conserved transfer threshold process
We analyze numerically the critical behavior of an absorbing phase transition
in the conserved transfer threshold process. We determined the steady state
scaling behavior of the order parameter as a function of both, the control
parameter and an external field, conjugated to the order parameter. The
external field is realized as a spontaneous creation of active particles which
drives the system away from criticality. The obtained results yields that the
conserved transfers threshold process belongs to the universality class of
absorbing phase transitions in a conserved field.Comment: 6 pages, 8 figures, accepted for publication in Phys. Rev.
Randmoness and Step-like Distribution of Pile Heights in Avalanche Models
The paper develops one-parametric family of the sand-piles dealing with the
grains' local losses on the fixed amount. The family exhibits the crossover
between the models with deterministic and stochastic relaxation. The mean
height of the pile is destined to describe the crossover. The height's
densities corresponding to the models with relaxation of the both types tend
one to another as the parameter increases. These densities follow a step-like
behaviour in contrast to the peaked shape found in the models with the local
loss of the grains down to the fixed level [S. Lubeck, Phys. Rev. E, 62, 6149,
(2000)]. A spectral approach based on the long-run properties of the pile
height considers the models with deterministic and random relaxation more
accurately and distinguishes the both cases up to admissible parameter values.Comment: 5 pages, 5 figure
Cloning and characterization of the Yersinia enterocolitica serotype O:9 lipopolysaccharide O-antigen gene cluster
Crossover phenomenon in self-organized critical sandpile models
We consider a stochastic sandpile where the sand-grains of unstable sites are
randomly distributed to the nearest neighbors. Increasing the value of the
threshold condition the stochastic character of the distribution is lost and a
crossover to the scaling behavior of a different sandpile model takes place
where the sand-grains are equally transferred to the nearest neighbors. The
crossover behavior is numerically analyzed in detail, especially we consider
the exponents which determine the scaling behavior.Comment: 6 pages, 9 figures, accepted for publication in Physical Review
Moment analysis of the probability distributions of different sandpile models
We reconsider the moment analysis of the Bak-Tang-Wiesenfeld and the Manna
sandpile model in two and three dimensions. In contrast to recently performed
investigations our analysis turns out that the models are characterized by
different scaling behavior, i.e., they belong to different universality
classes.Comment: 6 pages, 6 figures, accepted for publication in Physical Review
Tricritical directed percolation
We consider a modification of the contact process incorporating higher-order
reaction terms. The original contact process exhibits a non-equilibrium phase
transition belonging to the universality class of directed percolation. The
incorporated higher-order reaction terms lead to a non-trivial phase diagram.
In particular, a line of continuous phase transitions is separated by a
tricritical point from a line of discontinuous phase transitions. The
corresponding tricritical scaling behavior is analyzed in detail, i.e., we
determine the critical exponents, various universal scaling functions as well
as universal amplitude combinations
Green biomass – protein production through bio-refining.
The aim of this report is to summarize our present knowledge on the bio-technical as well as economic issues in relation to value creation of green biomass in Denmark. This includes many types of knowledge from the different types of actors included in activities going on at present in this field. To start the work, a kick-off workshop was held in Copenhagen in January 2016, where a range of stakeholders from many fields enthusiastically expressed their views and ideas as regards what to include and take into account in the report. We have tried to include these as far as possible. Thus a number of persons have contributed directly in the writing process whereas as others have contributed with particular overall insight
Finite-size scaling of directed percolation above the upper critical dimension
We consider analytically as well as numerically the finite-size scaling
behavior in the stationary state near the non-equilibrium phase transition of
directed percolation within the mean field regime, i.e., above the upper
critical dimension. Analogous to equilibrium, usual finite-size scaling is
valid below the upper critical dimension, whereas it fails above. Performing a
momentum analysis of associated path integrals we derive modified finite-size
scaling forms of the order parameter and its higher moments. The results are
confirmed by numerical simulations of corresponding high-dimensional lattice
models.Comment: 4 pages, one figur
The Bak-Tang-Wiesenfeld sandpile model around the upper critical dimension
We consider the Bak-Tang-Wiesenfeld sandpile model on square lattices in
different dimensions (D>=6). A finite size scaling analysis of the avalanche
probability distributions yields the values of the distribution exponents, the
dynamical exponent, and the dimension of the avalanches. Above the upper
critical dimension D_u=4 the exponents equal the known mean field values. An
analysis of the area probability distributions indicates that the avalanches
are fractal above the critical dimension.Comment: 7 pages, including 9 figures, accepted for publication in Physical
Review
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