The rock and ice mechanics lab at Lamont-Doherty is led by PIs Heather Savage, Christine McCarthy and Ben Holtzman. We are in the process of growing our lab and building our experimental program. Along with a team of postdocs, undergrads, grads, and longtime staff engineer Ted, we are rehabilitating and revamping some of the old equipment and building new rigs for exciting new experiments on both rock and ice. You can follow along with our progress here.

Thursday, 24 November 2011

Research Trip: Edinburgh

For the last 30 days I was in Edinburgh on a research exchange visit. It was an absolutely wonderful time to be visiting Scotland. The days were brisk, but not that cold and somehow I managed to avoid most of the rain. 

The visit was funded by a branch of the European Science Foundation, called MicroDICE. Their purpose is to promote the exchange of science and techniques between Universities and countries, especially if it is concerning the microstructures of Ice. 

I was visiting Jane Blackford, who is in the Materials Science department of the University of Edinburgh.  Here's Jane with the fields of outer Edinburgh below her. Whenever we weren't in the lab, we tried to sneak out to the surrounding hills for a hike or to the local climbing gym for a route or two.

Our research goal was to measure the "dihedral angle" of sulfuric acid and ice, that is, the wetting angle that a liquid acid solution makes in the corners of ice grains, which is determined by the surface energies. Sulfuric acid has been found in polar ice packs and is thought to exist on icy moons in the outer solar system. The reason for measuring the angle is because if the angle is very large (>60 degrees), sulfuric acid would be stuck and confined to the corners of grains, but if the angle is small (<60 degrees) it could travel through interconnected veins of liquid. Traveling liquid acid could really influence the physical properties of ice, so it is an important characteristic to measure. We sprayed a solution of ~5%acid into liquid nitrogen so that it would flash freeze into droplets that we collected and put into these little aluminum containers (right). Then we let the samples "cook" at various temperatures that were below the freezing temperature of ice yet above the freezing temperature for the liquid acid solution. We let them sit like that for about a week and then we quenched them in liquid nitrogen to capture that microstructure.  Then it was off to the Biology department to visit Chris Jeffree and his scanning electron microscope that is specially equipped to handle frozen samples (below).
Chris was an absolute wizard with the SEM and managed to take hundreds of images of dihedral angles. I am now in the process of measuring all those angles, first by hand and then electronically. Publication coming soon!

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