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SUMMARY:The three-dimensional morphology and topology of dendritic mushes 
 - Peter Voorhees (Northwestern)
DTSTART:20090205T140500Z
DTEND:20090205T151500Z
UID:TALK16680@talks.cam.ac.uk
CONTACT:Doris Allen
DESCRIPTION:Solid-liquid mixtures produced following dendritic solidificat
 ion are morphologically complex with spatially varying mean and Gaussian i
 nterfacial curvature.  The morphology and topology of these mixtures set t
 he properties of these systems\, such as the permeability of the mush. The
  structure of the mush is determined by coarsening\, a process wherein reg
 ions of interface with large curvature grow at the expense of regions of i
 nterface with small curvature.   To understand the manner in which these s
 ystems evolve during coarsening\, we have employed in-situ three-dimension
 al x-ray tomography and phase-field simulations. The evolution of the inte
 rface shape distribution\, the probability of finding a patch of interface
  with a certain mean and Gaussian curvature\, is determined. The experimen
 ts also show the importance of topological singularities\, such as the pin
 ching of tubes of liquid\, in the coarsening process. We find that the exp
 erimentally determined temporal power law governing the pinching process a
 grees with theory.  We will also discuss the evolution of the genus\, or E
 uler characteristic\, of the interfaces during coarsening.
LOCATION:MR15\, Centre for Mathematical Sciences
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