Last week was the annual convention for the American Geophysical Union (AGU), held each year in San Francisco. More than 20,000 earth scientists gathered to share their research, network and collaborate on new projects. A big crew of folks from our lab were in attendance. Both Heather and Nicholas gave talks and Rachel, Mandy, and I presented posters about our work. Below, Rachel shows off her recent results from the paleothermometer project that she has with Heather and Pratigya.
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.
Wednesday, 21 November 2012
Just like Barry Manilow, we are singing the praises of our visiting scientist, Mandy Duda. She came to Lamont this fall to run some experiments on the triaxial deformation apparatus. Her visit is funded by a postdoc fellowship from the German funding agency, DAAD. Her plan is to do some cyclical loading of rock samples, under confining pressure at various temperatures. But before she could start getting some data, she and Ted had a lot of work to do. A new burly intensifier to control confining pressure was added and connected to the hydraulic plumbing system (below left) and a Haskel air booster was wired up to help apply the confining pressure (below right).
After a lot of troubleshooting, she is now able to load her samples. Here she has wrapped her Westerly granite samples with copper tubing and is attaching it to the top closure nut. The blue stuff is rubber tubing that seals the interface between the sample and the end caps. Wires coming out the bottom (top) of the closure nut (which will be inverted when the sample is loaded) will send the temperature measurements to the command center and the computer.
It's go time! Here Mandy and Ted are at the command center applying a confining pressure to the sample for the first time. The rig has no trouble going up to and holding pressure at 60 MPa. Success! Next they will try to apply a vertical load to a sample, in addition to the confining pressure. Can't wait to see the results of her cyclic loading experiments!
Monday, 20 August 2012
At the experimentalist's workshop, Ted and I tinkered with the design for the ice rig. While I scribbled around on graphing paper, Ted transferred my ideas to a digital CAD-style schematic and fine-tuned the bottom loading feature. It's coming along...
Friday, 17 August 2012
Ted, Heather, and I are off in Boston at a workshop for experimentalists, so there's not a lot of progress in the lab at the moment. In the meantime I thought I'd share some pictures taken during my vacation in the Netherlands last week. In a small town near Amsterdam there is an open-air museum called Zuiderzee, which is an entire 17th century Dutch fishing village. In addition to all kinds of other aspects related to life at that time (smoking fish, doing laundry, burning coal, rope-making, etc.) the museum had a guy doing some woodworking using an old-school, foot-powered lathe. It looked pretty fun.
Friday, 13 July 2012
Summer at Lamont is a glorious thing. No classes, no reading groups, no seminars. It's all just about research and finding ways to enjoy the sun. This year a bunch of us kicked off the summer with the First Annual Crawfish boil. Tim (below, aproned) spent some time in the Big Easy, so he knows how it should all go down. He flew in an ungodly amount of live craw daddies from Louisiana (seriously, he picked them up at the airport and everything!) brought potatoes, corn, andouille, some secret spices, and pots big enough to feed an army. While we looked on and cheered, he boiled the whole thing up.
The feast was spread out on a newspaper and we all devoured it with nothing but our hands. So tasty!
One of the great things about Lamont is the wild life. Even though we're only a half hour from Manhattan, we're essentially in the woods here. Pretty much year round we have regular sightings of deer, wild turkeys, squirrels, and bunnies. With the onset of spring and summer, we also start to see baby things. All summer we've been watching this pair of geese and their pack of goslings right outside our office window.
Well they ate and they ate and now, mid-summer, they are all grown up! (They also have a very unhealthy confidence around humans and get VERY close to us. This was not taken with a zoom lens)
Summer is also the time for campus construction. Here a huge crane is being used to make improvements to the core lab. We are also having the second floor of the seismology building completely renovated. I can hear the lovely cacophony of saws and sledgehammers right now actually. (Okay so there is some downside to the summer activities. But we'll get lots of new, much-needed office space, so it's worth it). Next to the core lab some folks have also started a new Lamont community garden. Volunteers have pitched in to put up a new fence with chicken wire to keep out the gophers and, below, are busy tilling and planting.
And during the summer everyone gets out to enjoy their sport of choice. The soccer players have a regular crew of folks come out on Mondays, Wednesdays, and Fridays at lunch. Just beyond their field, you'll see volleyball net up for the ballers who play on Tuesdays and Thursdays at 1:00. There is even yoga on Tuesdays in the old Lamont hall library. I have been trying to get a regular ultimate frisbee game going as well, but we are having a hard time getting a consistent group together with everyone's summer travel schedules. I'll keep trying to rally the troops.
Friday, 6 July 2012
Today's big accomplishment in the lab was that I made the frame upon which the ice rig will sit. The facilities folks brought over some bars and I used the green unistrut fittings leftover from the renovation to hold it together. I never had an erector set growing up, but I imagine it was quite a bit like this...that is, incredibly fun! I still have to make sure things are level, tighten all the bolts, and affix the base plates to the dock, but it is getting pretty close. The ultimate test will be whether it can hold 300-400 lbs of rig on top of it without toppling over on me. Fingers crossed.
Tuesday, 3 July 2012
So now that the thermocouples have all been wired up, it is time to move on to the other forms of feedback that my cryo-friction rig will receive. Since we will be applying a biaxial load, we will need at least two load cells. We've decided to actually use three load cells (two horizontally and one vertically) so that we can be sure the normal load is consistent across the horizontal pistons (see here for schematic). In order to take the voltage signal from the load cell to the computer (and to display the current values), we need these type of card+meter panels. We salvaged a couple from old rigs but that plexiglass one is broken (and doesn't match...tacky!) and needs to be replaced.
There are companies that sell the perfect size of aluminum front plates with holes in all the right places, but they want ~$30 a pop for them. Money is a bit tight here in the ice research program, so I decided I would instead cut down my own aluminum panels from some other sheets we had on hand. First I cut down the length (though shown below in the milling machine, I actually used the saw) and then put the plate in the milling machine to make the square hole for the meter and small holes for screws. Those rounded edges on my square are the sign of a very poor cut job, but fortunately the placement of the meter will hide all the flaws
The front panel of the meter has tabs that are pushed through the holes around the square and the small electronic card is attached from behind with screws.
Friday, 15 June 2012
Exciting stuff happening this week in the rock mechanics lab. My aluminum plates for the ice rig arrived today so I started marking up the center lines and worked on my design to figure out precisely where we will drill holes for the tie rods.
MEANWHILE Heather, Rachel, and Pratigya have been making great strides in their paleothermometer project!
The idea for the study is that certain organic matter can be used as an indicator of temperature. With time and temperature, particular organics go through known reactions. The reactions can only go one way, so the altered material captures the peak temperature, even after things cools down. During an earthquake, fault rocks are believed to get pretty hot from frictional heating, but the extent of this has not been well constrained. Heather and Pratigya came up with the idea that if they can analyze the thin layer of sedimentary rock in the middle of the fault zone to look for specific altered organic material, this will tell them the temperature range that the fault experienced. For a better description of the project, check out this cool TED-style talk they gave at a Lamont community seminar. Before they can really start analyzing the fault rocks, however, they need to establish good reference values. So they are now taking crushed up sedimentary rock and are systematically heating it to known temperatures and durations. Here the team troubleshoots the new rig and starts developing the experimental protocol.
They heat the crushed up rock rapidly (simulating frictional heating in faults) in the tube below (that they call a "bomb") with that heating coil wrapped around the outside. Although the times, temps, and pressures are considerably less than what, say, large reserves of organic material in the earth experience, the initial stages of the reaction are similar to those that create petroleum. Even though they are working with only a teaspoon or so of material, the smell is simply horrendous. It's like being in the middle of an oil refinery.
They measure the temperature inside the bomb with thermocouples and monitor it with the panel of meters below. The Omega black box underneath is called a data acquisition system (DAQ) and is used to send data to the computer.
Here the undergraduate intern Rachel starts an experiment by turning on the gas while Ted looks on.
Wednesday, 13 June 2012
Parts are beginning to come in for the new ice rig. I'm getting excited about putting things together. One thing that I knew I could begin working on while we wait is the electronics to run the rig. We'll have a tower sitting next to the friction apparatus, which will have panels for temperature control, load and position monitoring, signal conditioners for the strain gauges etc. The easiest of these to wire up, in my opinion, is the temperature control. So I started there first. The triax was once used for high temperature work and so it had a panel of thermocouple meters that I could salvage. However, that panel wouldn't fit into my tower, so I had to start from scratch. Here is a pretty piece of painted aluminum specifically made for this purpose (circa 1970 I suspect). First I measured and penciled on my desired cuts,...
...loaded it into the milling machine,...
...and got to work.
I made five squares that will hold the meters, five half-inch holes to hold the fuses, and 10 tiny holes to hold five switches and five blanks (in case something comes up in the future).
The next step was to fit all those pieces in their places and wire it up. I first wired it up just like it was done before, so Ted could draw me a circuit diagram for the existing set up. Then I could decide what I wanted my rig to do instead and make the appropriate changes. In this case I will have one meter that will control the temperature of the cryostat and the other four will just be monitoring the temperature in various parts of the rig. I attached all the thermocouples (blue type Ts for low temp work) and Voila!
Tuesday, 22 May 2012
While we wait for all the parts to be delivered to make our new ice rig, I decided to do a little lab do-it-yourself work. We had a small section of extra wood countertop laying around from the old tops that were ripped out and so I bought some new legs from my tiny startup fund.
I sanded the counter top to remove the old stains and grooves and covered both sides with wood treatment wax. Then I buffed it smooth. Now I have my own little corner work bench for ice-related projects.
Tuesday, 15 May 2012
Lab renovation was on hiatus this month while Heather and I were diligently working on an NSF proposal and Ted was out at sea. Ted goes out to sea quite a bit. Back in January he joined a multi-University collaboration to deploy a slew of Ocean bottom seismometers (OBSs) in the Marianas. They used this bad boy, the Tommy Thompson research vessel, shown docked at the Guam Navy pier.
I should point out that all of these pictures come courtesy of Doug Wiens of WashU St. Louis, shown below with our own David Gassier and Brent Evers of IRIS. Doug was the lead scientist on the project.
Here the captain of the ship explains how the OBSs should be deployed.
The crew worked round-the-clock deploying the seismometers. Here's our Ted and other Lamonters working the night shift. The crew put out an amazing 85 seismometers in two weeks! Incredible!
Sunday, 5 February 2012
The machine shop finished making us nice cylinders, to which we applied all those strain gauges and wires. Check out that pretty copper-colored patina on the outside. That comes from a successful heat treatment, which locks in the desired hardness. Our old ones didn't have this patina, which may be one indication of why they crapped out on us. We also had the shop make us some hemispherical seats for the load cells. The piece attached directly to the piston has a convex surface and the large visible partner piece has a concave surface. That way, when you apply the load any small deviations in alignment are worked out. Above is a our vertical load cell and below is the horizontal, which applies the normal stress.
Friday, 13 January 2012
This week we made a trip to the machine shop on the other side of campus. It was my first time going and was I in for a treat. The purpose of the visit was to place an order with the shop to build us some new load cells and hemispherically seated pistons. We were getting quirky signals from our load cells and suspected that they had been overloaded and damaged. To test our suspicion we popped one into the Rockwell hardness tester to the right. We first had to try a bunch of standards, since we weren't entirely sure the tester still worked. But after getting consistent values with the known standards, we measured our load cell. Yikes! It was far softer than it should be. Poor baby was broken. Good thing the shop was available to start on some new cylinders. We'll add the strain gauges and wiring to them next week.
While we were over there we started poking around at some of the old machines. Check out these ancient drill presses. I think they still actually work.
But this dirty little phone booth station in the middle of the shop was my favorite. When exactly those notes on the back wall were written probably nobody knows, but I bet they contain every important phone number in the NY and NJ area codes. I wouldn't throw them out either. Some things you just don't mess with.
Like the Hear-Here.