7,645 research outputs found
Relevance of Abelian Symmetry and Stochasticity in Directed Sandpiles
We provide a comprehensive view on the role of Abelian symmetry and
stochasticity in the universality class of directed sandpile models, in context
of the underlying spatial correlations of metastable patterns and scars. It is
argued that the relevance of Abelian symmetry may depend on whether the dynamic
rule is stochastic or deterministic, by means of the interaction of metastable
patterns and avalanche flow. Based on the new scaling relations, we conjecture
critical exponents for avalanche, which is confirmed reasonably well in
large-scale numerical simulations.Comment: 4 pages, 3 figures; published versio
Universality classes and crossover behaviors in non-Abelian directed sandpiles
We study universality classes and crossover behaviors in non-Abelian directed
sandpile models, in terms of the metastable pattern analysis. The non-Abelian
property induces spatially correlated metastable patterns, characterized by the
algebraic decay of the grain density along the propagation direction of an
avalanche. Crossover scaling behaviors are observed in the grain density due to
the interplay between the toppling randomness and the parity of the threshold
value. In the presence of such crossovers, we show that the broadness of the
grain distribution plays a crucial role in resolving the ambiguity of the
universality class. Finally, we claim that the metastable pattern analysis is
important as much as the conventional analysis of avalanche dynamics.Comment: 10 pages, 7 figures, 1 table; published in PRE as the full paper of
PRL v101, 218001 (2008
Economic Instruments and the Pollution Impact of the 2006-2010 Vietnam Socio-Economic Development Plan
The current study derives optimal growth paths for pollution emission charges, in order to control future water pollution emissions in the Vietnamese manufacturing sector. The study builds on a prior study, which estimated the manufacturing sector pollution impact of the 2006- 2010 SEDP development plan for Vietnam (Jensen et al.; 2008). The current study demonstrates that effective implementation and moderate expansion of optimal emission charges, under certain conditions, could have been used, as part of the 2006-2010 SEDP development plan, to control pollution emissions at 2005 levels. Moreover, such a scenario would have been accompanied by a moderate expansion in fiscal revenues and a relatively minor economy-wide efficiency loss. The current study, therefore, suggests that effective implementation and gradual expansion of pollution emission charges should be incorporated into future SEDP development plans, in order to control pollution emissions as development progresses in Vietnam.Vietnam, manufacturing, CGE
The mean-field theory for attraction between like-charged macromolecules
A mean-field theory based on Gibbs-Bogoliubov inequality is constructed to
study the interactions between two like-charged polyions. It is shown that
contrary to the previously established paradigm, a properly constructed
mean-field theory can quantitatively account for the attractive interactions
between two like-charged rods.Comment: 5 pages, 2 figures, elsart.sty neede
Counterion Condensation and Fluctuation-Induced Attraction
We consider an overall neutral system consisting of two similarly charged
plates and their oppositely charged counterions and analyze the electrostatic
interaction between the two surfaces beyond the mean-field Poisson-Boltzmann
approximation. Our physical picture is based on the fluctuation-driven
counterion condensation model, in which a fraction of the counterions is
allowed to ``condense'' onto the charged plates. In addition, an expression for
the pressure is derived, which includes fluctuation contributions of the whole
system. We find that for sufficiently high surface charges, the distance at
which the attraction, arising from charge fluctuations, starts to dominate can
be large compared to the Gouy-Chapmann length. We also demonstrate that
depending on the valency, the system may exhibit a novel first-order binding
transition at short distances.Comment: 15 pages, 8 figures, to appear in PR
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