Title:
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Side-branch growth in two-dimensional dendrits. Part I: Experiments
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Author:
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Couder, Yves; Maurer, J.; González Cinca, Ricard; Hernández Machado, Aurora
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Other authors:
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Universitat de Barcelona |
Abstract:
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The dynamics of growth of dendrites’ side branches is investigated experimentally during the crystallization of solutions of ammonium bromide in a quasi-two-dimensional cell. Two regimes are observed. At small values of the Peclet number a self-affine fractal forms. In this regime it is known that the mean lateral front grows as
t
0.5
. Here the length of each individual branch is shown to grow (before being screened off) with a power-law behavior
t
α
n
. The value of the exponent
α
n
(
0.5
⩽
α
n
⩽
1
)
is determined from the start by the strength of the initial disturbance. Coarsening then takes place, when the branches of small
α
n
are screened off by their neighbors. The corresponding decay of the growth of a weak branch is exponential and defined by its geometrical position relative to its dominant neighbors. These results show that the branch structure results from a deterministic growth of initially random disturbances. At large values of the Peclet number, the faster of the side branches escape and become independent dendrites. The global structure then covers a finite fraction of the two-dimensional space. The crossover between the two regimes and the spacing of these independent branches are characterized. |
Subject(s):
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-Cristal·lografia -Estructura cristal·lina (Sòlids) -Solidificació -Experiments -Ciència dels materials -Crystallography -Layer structure (Solids) -Solidification -Materials science |
Rights:
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(c) The American Physical Society, 2005
http://dx.doi.org/10.1103/PhysRevE.71.031602 |
Document type:
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Article Article - Published version |
Published by:
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The American Physical Society
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