1,531 research outputs found
Comment on `Renormalization-Group Calculation of the Dependence on Gravity of the Surface Tension and Bending Rigidity of a Fluid Interface'
It is shown that the interface model introduced in Phys. Rev. Lett. 86, 2369
(2001) violates fundamental symmetry requirements for vanishing gravitational
acceleration , so that its results cannot be applied to critical properties
of interfaces for .Comment: A Comment on a recent Letter by J.G. Segovia-L\'opez and V.
Romero-Roch\'{\i}n, Phys. Rev. Lett.86, 2369 (2001). Latex file, 1 page
(revtex
Convection cells induced by spontaneous symmetry breaking
Ubiquitous in nature, convection cells are a clear signature of systems
out-of-equilibrium. Typically, they are driven by external forces, like gravity
(in combination with temperature gradients) or shear. In this article, we show
the existence of such cells in possibly the simplest system, one that involves
only a temperature gradient. In particular, we consider an Ising lattice gas on
a square lattice, in contact with two thermal reservoirs, one at infinite
temperature and another at . When this system settles into a non-equilibrium
stationary state, many interesting phenomena exist. One of these is the
emergence of convection cells, driven by spontaneous symmetry breaking when
is set below the critical temperature.Comment: published version, 2 figures, 5 page
An Analysis of Cohesion Devices in Political News of the Jakarta Post: a Discourse Analysis Approach
Newspaper is one of an effective tool to deliverthoughts or even to get the information. The languageof journalism in the newspaper is related to the actionor opinion from people and it is conveyed into a text.This research is aimed at knowing the function of thetext by analyzing the text based on the Discourseanalysis. The researcher uses cohesion devices toanalyze the text of political news in an onlinenewspaper. This research is designed as a descriptiveresearch where the researcher conducts the researchin order to knowing the phenomenon in the field ofstudy. The researcher, then, analyze the text based onthe cohesion devices such as substitution, ellipsis,conjunction, reference and lexical cohesion. Theresult of this research shows that the text in an onlinenewspaper which is analyzed in this research has agood structure of cohesiv
Fluctuations and correlations in population models with age structure
We study the population profile in a simple discrete time model of population
dynamics. Our model, which is closely related to certain ``bit-string'' models
of evolution, incorporates competition for resources via a population dependent
death probability, as well as a variable reproduction probability for each
individual as a function of age. We first solve for the steady-state of the
model in mean field theory, before developing analytic techniques to compute
Gaussian fluctuation corrections around the mean field fixed point. Our
computations are found to be in good agreement with Monte-Carlo simulations.
Finally we discuss how similar methods may be applied to fluctuations in
continuous time population models.Comment: 4 page
Roughening transition, surface tension and equilibrium droplet shapes in a two-dimensional Ising system
The exact surface tension for all angles and temperatures is given for the two-dimensional square Ising system with anisotropic nearest-neighbour interactions. Using this in the Wulff construction, droplet shapes are computed and illustrated. Letting temperature approach zero allows explicit study of the roughening transition in this model. Results are compared with those of the solid-on-solid approximation
Factorised Steady States in Mass Transport Models on an Arbitrary Graph
We study a general mass transport model on an arbitrary graph consisting of
nodes each carrying a continuous mass. The graph also has a set of directed
links between pairs of nodes through which a stochastic portion of mass, chosen
from a site-dependent distribution, is transported between the nodes at each
time step. The dynamics conserves the total mass and the system eventually
reaches a steady state. This general model includes as special cases various
previously studied models such as the Zero-range process and the Asymmetric
random average process. We derive a general condition on the stochastic mass
transport rules, valid for arbitrary graph and for both parallel and random
sequential dynamics, that is sufficient to guarantee that the steady state is
factorisable. We demonstrate how this condition can be achieved in several
examples. We show that our generalized result contains as a special case the
recent results derived by Greenblatt and Lebowitz for -dimensional
hypercubic lattices with random sequential dynamics.Comment: 17 pages 1 figur
Study of the superconducting properties of the Bi-Ca-Sr-Cu-O system
High Temperature Superconductivity in the Bi-Ca-Sr-Cu-O System has been observed and has attracted considerable attention in 1988. The 80 K superconductivity phase has been identified to have a composition of Bi2CaSr2Cu2Ox, while the 110 K phase as reported in the literature has a possible composition of Bi2Ca2Sr2Cu3Ox. Researchers present here a study of the electrical properties of bulk samples of the slowly cooled and rapidly quenched 2:1:2:2 system. The samples used in this study were prepared from appropriate amounts of Bi2O3, CuO, SrCO3, CaCO3
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