17,905 research outputs found
Model inspired by population genetics to study fragmentation of brittle plates
We use a model whose rules were inspired by population genetics, the random
capability growth model, to describe the statistical details observed in
experiments of fragmentation of brittle platelike objects, and in particular
the existence of (i) composite scaling laws, (ii) small critical exponents \tau
associated with the power-law fragment-size distribution, and (iii) the typical
pattern of cracks. The proposed computer simulations do not require numerical
solutions of the Newton's equations of motion, nor several additional
assumptions normally used in discrete element models. The model is also able to
predict some physical aspects which could be tested in new experiments of
fragmentation of brittle systems.Comment: We have modified the text in order to make the description of the
model more clear. One Figure (Figure 1) was introduced showing the steps of
the dynamics of colonization. Twelve references were adde
T-Duality in 2-D Integrable Models
The non-conformal analog of abelian T-duality transformations relating pairs
of axial and vector integrable models from the non abelian affine Toda family
is constructed and studied in detail.Comment: 14 pages, Latex, v.2 misprints corrected, reference added, to appear
in J. Phys.
Structural properties of crumpled cream layers
The cream layer is a complex heterogeneous material of biological origin
which forms spontaneously at the air-milk interface. Here, it is studied the
crumpling of a single cream layer packing under its own weight at room
temperature in three-dimensional space. The structure obtained in these
circumstances has low volume fraction and anomalous fractal dimensions. Direct
means and noninvasive NMR imaging technique are used to investigate the
internal and external structure of these systems.Comment: 9 pages, 4 figures, accepted in J. Phys. D: Appl. Phy
Lorentz symmetry breaking in the noncommutative Wess-Zumino model: One loop corrections
In this paper we deal with the issue of Lorentz symmetry breaking in quantum
field theories formulated in a non-commutative space-time. We show that, unlike
in some recente analysis of quantum gravity effects, supersymmetry does not
protect the theory from the large Lorentz violating effects arising from the
loop corrections. We take advantage of the non-commutative Wess-Zumino model to
illustrate this point.Comment: 9 pages, revtex4. Corrected references. Version published in PR
Vertex Operators and Soliton Solutions of Affine Toda Model with U(2) Symmetry
The symmetry structure of non-abelian affine Toda model based on the coset
is studied. It is shown that the model possess
non-abelian Noether symmetry closing into a q-deformed
algebra. Specific two vertex soliton solutions are constructed.Comment: 17 pages, latex, misprints corrected, version to appear in J.Phys
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