Dartmouth Engineer - The Magazine of Thayer School of EngineeringDartmouth Engineer - The Magazine of Thayer School of Engineering

Dartmouth Team First to Transport Arctic Sea Ice at Original Temperature

By Anna Fiorentino
April 2015 • Thayer By Degrees:

Professor Rachel Obbard '06 and her team of PhD, MS and BE students made history in 30 below temperatures using the first-ever contraption—that they designed over the last three years at Thayer—to successfully transport sea ice cores they extracted from the Artic at their original temperature. Their expedition, which came to a close March 28, had important implications for the Earth's climate. Their ICE-MITTs (Ice Core Extraction while Maintaining In-situ Temperature Transitions) maintain the temperature of the ice cores after extraction so that they can accurately model the complex brine networks in a lab.

"After six weeks off the coast of Barrow, Alaska, I finally began to accept that the ICE-MITTs did indeed work and had been maintaining a temperature gradient on their own without me checking in on them ever few hours," says engineering PhD student Ross Lieb-Lappen, who, with Ellyn Golden '17 and MS student Natalie Afonina '15 made the trek out to Alaska with Obbard. "It has taken several years to develop this from a crazy idea into actuality, so the most exciting part of the trip, scientifically, is seeing it all come together."

Working from a prototype developed by Cook Engineering Design Center Fellow Gunnar Pope Th'14, Lieb-Lappen built nine of the ten ICE-MITTs in four months last fall. "I still knew that we had a logistical nightmare ahead trying to fly them to Fairbanks and then a 4,700 mile road trip home," adds Lieb-Lappen. But make it home with ice cores they did.

The invention by Obbard and her team represents a significant step toward helping predict the future of sea ice in the Arctic. Sea ice, which can be as much as five meters thick, controls the exchange of heat, fluid, gases and chemicals between the ocean and the atmosphere. In order to study its microstructure, it should ideally be kept at its original temperature of minus 2 degrees Celsius at its base and as low as minus 25 degrees Celsius at its top.

ICE-MITT team

"The field work was so challenging, requiring us to think on our feet, and adapt to changing conditions," says Obbard. "Barrow has the basics, but anything that couldn't be purchased at the grocery or NAPA Auto Parts had to be flown in, and that could take a week. We learned to rely on our wits, varied skill sets, and experience. I ended every day bone-tired, but satisfied, we got our coring and packing routine down pat and solved every problem that came up."

After collecting the ice samples, the group drove from Fairbanks, Alaska in a truck carrying the sea ice in ICE-MITTs across the country to Dartmouth's Ice Research Laboratory at Thayer. Powered by a generator inside the truck, the custom-built refrigerated, insulated boxes each housed two one-meter-long sections of ice core. The ice cores are cooled with Peltier thermoelectric devices mounted next to heat sinks and fans that draw heat out and remove it from the box. The Peltier device, which looks like a small square sandwich, is a solid-state heat pump that transfers heat from one side to the other when electrical energy is applied.

"I was very shocked to see all 20 temperature gradients still in tact after being unplugged for three and a half hours on a plane from Barrow to Fairbanks," says Lieb-Lappen. "It was even more exciting to have them all loaded up in the U-Haul, powered by two generators, and seeing it all work as we drove cross-country."

Obbard and her team stopped on their ride back to give presentations at schools and museums in Barrow, Edmonton, Madison, WI, Chicago, and Detroit about sea ice and their fieldwork in the Arctic.

ICE-MITT
Professor Obbard explains the ICE-MITT system.

"We visited the wonderful children of Boggs Educational Center in Detroit," says Golden, who headed up the group's outreach efforts. "The students showed us posters they had made of Arctic animals, and we shared our experiences with them."

The educational outreach was just one memorable experience during the expedition—they won't forget battling the elements out on the ice either. When the wind chill crept to minus 55 degrees, the team was forced to retreat to their bungalow at the former Naval Arctic Research Lab.

"I'm still surprised that all of the fine electrical components worked out in the cold and all 852 pieces of each ICE-MITT held together for the most part," says Lieb-Lappen. "Although nine of the ten boxes broke at some point (many multiple times), we were able to make the necessary repairs as we went."

And they managed to have a little fun too. Golden wound up adopting a husky-mix from a shelter in Alaska, and Lieb-Lappen encountered whole different kind of animal.

Polar Bear

"I saw three polar bears 30 feet from our truck right after the most incredible northern lights display and successfully extracting a multi-meter core and maintaining its temperature profile for the first time," says Lieb-Lappen. "Now that's what I call a good day."

The initial design for the ICE-MITT began three years ago with a group of ENGS 21: Introduction to Engineering students who tackled the challenge of finding a way to maintain the temperature of ice cores. The team created a single-core Peltier-based system that was cooled with circulating liquid in coils like the ones you see on the back of a refrigerator. In the spring of 2012, Afonina, who was part of that original group and is now pursuing her MS with Professor Ian Baker, took the ICE-MITT to the next design stage as an independent research project in ENGS 87: Undergraduate Investigations. She made significant progress on the control system, which is based on the open-source Arduino platform.

Then, over the fall and winter, an ENGS 89/90: Engineering Design Methodology and Project Initiation group took the ICE-MITT further, creating thermodynamic models and refining the unit's power electronics, but then hit a snag when the coolant system wasn't up to the job. Pope, who is now pursuing an MS with professor Ryan Halter, came on board in March to finish the design and build a working prototype. He replaced the liquid cooling system with an air-cooled one, improved the power and control electronics, and reduced the overall weight of the box.

All the hard work paid off, and the ICE-MITTs performed well in their first field test.

"Now that we know we can get sea ice to the lab with its original pore structure intact, we can accurately model that structure," says Obbard.

This work is part of a three-pronged project for the NSF's Division of Polar Programs that involves developing the ICE-MITT system, collecting a variety of first-year sea ice cores from locations around Barrow, and analyzing those cores using micro-computed tomography and applied mathematics. Dartmouth mathematics professor Scott Pauls is collaborating with the group to characterize the topology of brine networks in sea ice.

"The results of our work will help scientists understand how pore networks are organized in sea ice," says Obbard. "We are interested in porous materials in general and in the role brine networks play in sea ice, large and small. Brine channels form a habitat for marine microorganisms and contribute to the sea ice cover's role in the local, regional and global environment.

"What we find will help other scientists better understand the ocean-ice-atmosphere system, sea ice melt, the home to many photosynthetic marine biota and the higher food web that depends on it, and even the distribution and fate of pollutants," she adds.

Tags: alumni, climate change, environment, faculty, innovation, projects, research, STEM, students

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