Grad student Chris Burke today was awarded second place in the Photography and Illustration category of the Tufts Research Visualization Awards for his entry “Sphere Packing on Ellipsoidal Surfaces” at a special ceremony celebrating all the winners.  The image (shown above) highlights defects in the packing of spherical particles on ellipsoidal surfaces.

The primary goal of this work is to better understand how defects form in tightly packed collections of spheres on curved surfaces, specifically on surfaces with spatially varying curvature. This has applications in creating stable emulsions, which would be useful for manufacturing food items like low-fat mayonnaise or ice cream.

In this context, defects refer to particles which do not have six neighbors. On a flat surface, particles tend to form an orderly hexagonal lattice. However, on a curved surface this is no longer possible. Some particles are forced to have five or seven neighbors, and these are represented in the image as blue and green particles, respectively.

An interesting feature in these packed configurations is the presence of “scars,” or chains of defects in a blue-green-blue pattern. For large numbers of particles, these scars tend to be longer in order to minimize the stress felt by the packing. Our group is interested in how the size of these scars depends on the number of particles and on the shape of the surface.

Congratulations Chris!


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