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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, 1 December 2016

Cryostat 2.0

Our original cryostat for the friction rig was awesome. We made lots of improvements to the way that temperature is monitored (with RTDs now, which have much less error) and in the insulation, etc. We started using a protocol of placing the rocks and metal at the desired testing temperature in a chest freezer over night before we start an experiment. So we've got it to where we can load a sample, give it an hour or two to really level out to a steady temperature, and then we can just let it run for hours to days of testing at constant T. Using that cryostat, we ran our first series of experiments on the temperature dependence of ice on rock friction, which was written up in this paper.

However, the lowest temperature it could achieve was about -20 deg C, determined by the chiller that circulates methanol+water through cooling blocks on the side of the cryostat. That's completely fine for terrestrial applications, but we want to also test planetary ice. So we need to go colder. Much much colder! That's why Mike has begun working on Cryostat 2.0. This cryostat will instead use methanol cooled by liquid nitrogen to flow through copper coils directly adjacent to the sample. The plus-shaped sample housing sits on top of stiff, insulating material. 
It sits inside a box that will be insulated by creating a vacuum. More to come!





Sunday, 30 October 2016

Open House 2016

For this year's open house we went with a whole new format. Instead of cramming people into our little lab, we took up a space in one of the big tents. Here Mike talks about friction and uses our sliding blocks with different grit sandpaper to demonstrate roughness.
 Meanwhile, Rob mans the elastic properties booth, where we've got a piece of rock wired up with strain gauges. He asks guests to test their strength at squeezing a rock. This year we added a rubber cube as a reference and even went with a digital display (fancy!).

Additionally we opened up the back window of the lab where the cryofriction rig is housed and allowed people to "Step Right Up" and peer in to see an actual experiment in action.
Here Ted talks to the folks outside the window and demonstrates all of the components that go into a friction experiment.