text

The rock mechanics lab at Lamont-Doherty was once used by a famous experimental geologist, but then was quiet for awhile. Recently Lamont hired Heather Savage to take over the lab. She and a team of postdocs, undergrads, grads, and longtime staff engineer Ted are now rehabilitating and revamping the lab for exciting new experiments. I'm part of that team and I thought I would document the task with this blog. Enjoy!

Thursday, 19 February 2015

It's moving….IT'S ALIVE!!

Huge progress in the lab today. The last month or two have been filled with a whole lot of calibrating, adjusting, wiring….
…testing, cross testing and multi component cross testing. Ted has been working his butt off getting all the electronics to talk to each other just right, getting all the limits and failsafes to do their job, and fixing last minute hydraulic leaks.
And this afternoon, we had the load cells and LVDTs hooked up and the electronics driving the hydraulics pistons. We can make it move up and down on command, in either load or position control. This is huge! THE LDEO CRY-AX IS ALIVE! We can now start squeezing and sliding the heck out of stuff! Yeah!

adventures in standard ice

One of the important parts of any laboratory study is the preparation of samples. Currently we are focusing on the fabrication of rectangular polycrystalline ice samples that we will use in the ice friction experiments. Mike will also be using them in his senior thesis project. He will expose the samples of so-called "standard ice" to various temperature pulses and characterize how they respond. Scientists over the last few decades have perfected a method for making standard ice, although in all the previous cases they made cylinders, so we are doing something a little new. I previously reported on the rectangular die that we built. Well that has gone through a few changes, including a gasketed top that screws down to prevent leakage at the top. Plus, silicone sealant has been placed at all the seams and long risers were put on the top ports…
…so that we didn't have to get our hands wet opening valves while the die and large flask were submerged in the bath.
The idea with the standard ice is that you have packed "seed ice" and liquid water both equilibrated in a big tub of ice water, getting the whole system down to exactly zero degrees C. Then you pull a vacuum on the seed ice and open the valve to the inverted flask. The cold water floods the pore space of the seed ice. You then quickly put the flooded die in the cold room (-30C) atop a copper plate and insulate the sides, promoting bottom up directional freezing of the water you introduced. The process, we found, takes a couple of hours (not counting the making of the seed ice, which I'll report on later. That's a whole other can of worms) but then you are left with this giant bucket of ice water to throw away. Seemed wasteful. So we downsized the whole shebang to this much smaller bucket, lowered the risers, and swapped out the huge inverted flask for a small squirt bottle.
The result is this fully dense rectangle of crystalline ice. Here Mike is taking a slice with a wood saw so that we can take a closer look and see how we did.
He'll be imaging the samples with the microscope we have in the cold room and then analyzing the images for things like grain growth, porosity, fracturing, etc. Take special note of what he's wearing. After one day in the cold room, he knew there had to be a better way. He came back the next day with an old plastic hazmat suit that he'd rigged up with a blowdryer to make this custom warm suit. I've got an order in for a second!


Tuesday, 27 January 2015

Outreach: Brooklyn Elementary School Science Fair

This weekend I took the Rock Mechanics show on the road! A family from Brooklyn PS372 ("The Children's School") saw our set up at Open House, got my contact information, and asked me to come to their annual Science Day.

In addition to the rock mechanics table, there were things like electrical circuits, optical illusions, ultrasound, gardening, and making silly putty. We all set up our tables in the gymnasium before the kids arrived.
I figured that some of the kids may have already had some introduction to geology, so I brought a small collection of rocks. Sure enough, when I started talking about the rock cycle, a few yelled "Igneous!" and "Sandstone!" (okay, close enough). I also brought the rock with the strain gauges and goniometer, which is always a big hit.
And of course I brought our slider block demonstration of earthquakes. Though once they figured out how the seismometer app worked it was hard to see the small motions of the block sliding over their stomping and banging on the table. I wish I would have taken a picture or two of the kids in action, but once they started arriving I was doing demos almost nonstop for three hours. It was a fun but exhausting day.



Tuesday, 6 January 2015

The rock mechanics lab supports the arts!

Meet Denise Iris, a media artist and filmmaker, and our very own "Artist in Residence" at the rock mechanics lab. Okay, not officially, but we claim her as our own now. Denise is working on a multi-screen installation piece about climate change as personified by a lone polar explorer. She shot some great action footage with an actor out in polar bear country in the Arctic and wanted to compliment it with some more controlled shots of ice freezing and melting. She got in touch with us and spent a few weeks in the lab and cold room experimenting with different effects. Below she uses a blow torch to speed up the melting process on a block of ice. You can see a sample of this melting video at her FB page.
She used the microscope in the cold room to capture video of a drop of water freezing. She played around with different freezing surfaces and compositions, but I was too cozy in my warm office to go check on her. So I have no pictures of that.  
She also took an aquarium tank that Ted found on campus and filled it with water and a chunk of our "failed" seed ice (i.e. ice that has lots of tiny bubbles which are terrible for us experimentally, but wonderful for her artistically). 
Our PR department will be doing a more detailed story about Denise's visit and our unusual collaboration in the next few weeks. At the risk of being too meta, here is a picture of Kim taking a picture of Denise taking a picture of ice.
 And here are a couple of examples of what she came up with. These are just the stills. You should see the video that she created. That bubble that looks like a drop of mercury moves around in the most mesmerizing way. I just can't wait to see her final project.
 Gorgeous! Now don't you want an artist to spend time in your rock mechanics lab? You bet you do!





Monday, 8 December 2014

Rock mechanics on TV!

Today I did an interview for a public television program called SciTechNow. I was contacted because of my affiliation with Science Cheerleaders and because the head of that organization was not available for the interview. I talked mostly about that organization and SciStarter, an online citizen science group.  But it also gave me an opportunity to talk a little bit about the rock mechanics lab and about why I got into science.
This morning after dropping off the baby I headed down to 66th and Broadway to the Tisch WNET studios at Lincoln Center. First stop was up to the green room to get my hair and make-up done.
Then I was brought down to the waiting room couch, right there on the corner of Broadway. I was the last in a series of eight speakers.
When it was my turn, I was fitted with a microphone and the make-up artist touched me up, shellacking that stray hair back out of my eyes.
Hari was really nice and easy to chat with. He asked me several questions about Science Cheerleaders and about Sci Starter. I think I was a little like a deer in the headlights on my first question (I sure hope they do some editing) but after I got warmed up, it went pretty well. 
After the interview I recorded two segments for their  "Ask a Scientist" feature. This is where scientists try to provide an easy to understand answer to a science question in one minute or less. I answered "What is tidal heating?" and "How do we know what's inside the earth?"
I don't remember saying much about subduction zones, but apparently it is physically impossible for a geologist to give an interview and not make this hand gesture.
Afterward Hari took a photo with me. Pretty fun way to spend the morning, but I'm happy to be back in my grubby clothes and in the lab getting dirty again.




Saturday, 22 November 2014

Reaction driven cracking with Sarah

There's a new experimental project occurring in the rock mechanics lab right now. Sarah Lambart, who is usually over in the petrology labs, is conducting some preliminary desktop studies of reaction-driven cracking that may ultimately be performed in the triax. Below, her sample material sits within a steel cylindrical die and she is using weightlifting equipment to determine if the reaction rate depends on stress (it does!)
 Another test determines the rate of the reaction with warm basic fluid (but without stress).
Strain gages attached to a copper jacket around the sample should capture volume expansion and cracking caused by a reaction of water and calcium oxide. 
 Transducers attached to the sample will monitor cracking. Sarah tests one out and observes the signal.


Saturday, 15 November 2014

Cryostat stage 1

Our newest member of the lab is Mike Nielson, who will be doing his senior thesis project working on ice. Specifically he will be troubleshooting and calibrating the cryostat and testing standard ice samples for grain growth or degradation after thermal pulses.  On his first day he already made a big contribution to the ice project. Rather than the duct taped styrofoam contraption that I was envisioning for insulation, he suggested we use expanding foam to get a perfect fit to the cryostat dimensions. 
At home he built a wooden box lined with wax paper. We placed the cryostat inside the box and released two full cans of Great Stuff expanding foam in the area around it. A wooden bar over the top covered the ball bearing sleeve that the piston goes into. The bar also held down the cryostat when the foam expanded.
And did it ever expand!  He taped the sides so that the foam would "grow" toward the center. We actually worried that it wouldn't fully cover the top of the cryostat. Clearly we didn't have to worry. It covered completely and pushed its way out. After it fully dried, he easily removed it from the box,  cut the top off, and cut the insulation into two halves. Eventually we will use duct tape or velcro to make a seam that will hold the two parts together.
He cut a hole in the side to allow for the peltier cooling device and heat sink that I will discuss in more detail later. Shown here is a fan sink. In the next blog installment I will show the circulating liquid sink that we are now using instead. Stay tuned!