Leonid M. Martyushev, Pavel S. Terentiev
Unsteady growth of ammonium chloride dendrites during crystallization from an
aqueous solution in a thin capillary is experimentally investigated. Dependency
of the crystal area S on the time t for various sectors located along a primary
branch and sidebranches is measured. A hypothesis of the same ratio between the
area change and the area itself (S'(t)/S(t)) for different but simultaneously
growing parts of an unsteady dendrite is advanced and confirmed. This
conclusion allows proposing a curve for describing the evolution of the
dendrite area (or its part) of the form S(t)=const*exp(-b*t)*t^a, where a and b
are the parameters, whose values are determined in the paper. The
nondimensionalization of S(t) and S'(t)/S(t) (using the full dendrite growth
time) results in simple one-parameter functions depending on a single parameter
(a) (which is presumably associated only with physical and chemical
characteristics of the crystallized system and, in our case, equals 1.7+/-0.2).
View original:
http://arxiv.org/abs/1202.4252
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