Hanami 2019

Quite possibly the nicest hanami ever. Usually come mid-April we are freezing our butts off out there on the blue tarp. This year's hanami was warm and sunny. We had Atsuko Namiki visiting us from Hiroshima. We had a nice spread of food and Ben's shochu. Really nice time.

Is Rob making a still?

Came into the lab to find this. I have no idea what's going on here, but I love the looks of this curly tube funnel thing.

Progress on Cryostat version 3.0

In our ongoing efforts to make our cryostat go colder and colder, Mike designed these.

They are the cooling blocks that go right next to the sample and have chilled fluid (coming from a custom LN-controlled chiller that Mike made) pumped into those channels. 

The inner side (closest to sample) is high thermal conductivity aluminum and the outer side is insulating PMMA. In order to seal them together, both sides needed to be roughened. But he left the little viewing window smooth. That way we can see (and potentially image) the sliding interfaces.

More regelation

This fall we had 5 students from a local high school come one day a week for lab activities. In addition to a long term regelation project, each week there were lab exercises. These exercises
ranged from cheese squeezing, to phase equilibria, to earthquake triangulation. We also gave another go at the classic regelation experiment. I tried this with students in the summer and the ice pieces were too small and some wire was too thin. This time I think we got the right combination.

The idea is that the pressure is great enough just below the wire that it pressure melts the ice but then right above the wire the pressure is low and it refreezes, thereby trapping the wire inside the ice as it makes its way down. Theoretically, the thermal conductivity of the wire is important for the process.

Success!

The students then applied this idea to a long term project in which ice was placed on top of beads and a weight was placed on top. Each week they used a different size or different type of bead. In theory if the bead is embedded into the ice by viscous (solid-state) creep, then it wouldn't matter what type of metal was used. But if it occurs by regelation, then the type of metal (and therefore the thermal conductivity) is important. They had really nice results demonstrating a mix of both types of deformation depending on the conditions (particularly the size of the bead, which controls the stress). 

The work was all done in a commercial chest freezer, which isn't ideal for temperature control, since it oscillates with the freezer's duty cycle, but is good for a school project lasting all semester.

They became familiar with running experiments, taking notes, analyzing data and communication results (we had an informal poster session at the end of the term)

Rock Mechanics at AGU

This year's AGU was held in DC. It was fun to check out a new venue, but not fun getting lost trying to find everything. The convention space, which connected underground to the Marriott next door, was just cavernous. And I don't think we've all really mastered where to put ourselves.

Despite that, I did manage to make it to most everyone's posters ...

...including my own (though my shift was at 8am, so it was rough)

Allie and Jessy

I would be remiss if I didn't mention our visitors from Brown University this summer. Allie and Jessy are undergraduates in the geosciences department who wanted to gain some lab experience. They worked on measuring wave speeds in partially molten ice samples. This involved lots of time in the cold room...

Working with Mike, they put together this special baby cryostat to maintain temperature around samples. Inside the cooled cylinder sat a sample of ice + ammonia and on either side of the sample were ultrasonic transducers.

They were very careful, took excellent notes, and calculated error bars. At the end of the summer they presented their (tiny) poster at an informal poster session at Lamont.

And they did such a nice job, that we will publishing their results in an upcoming special edition of Geosciences about Interiors of Icy Ocean Worlds. Stay tuned for that and for great things to come from these young researchers!

Daning says goodbye

Last year we had a visiting grad student in our lab. Daning Zhong was working on a modeling project and helping with friction experiments in the lab.

In September she had to return to China because her 1 year visit was up. At Ted's goading, we took a walk around campus for a photo shoot. 

It was really nice having her visit. She did a great job applying the Aharonov and Scholz constitutive model of friction to high homologous temperature ice friction. Stay tuned for a Zhong et al. publication coming soon!