Aurelia Butler

Deep neural networks excel at finding patterns in datasets too vast for the human brain to pick apart. That ability has made deep learning indispensable to just about anyone who deals with data. This year, the MIT Quest for Intelligence and the MIT-IBM Watson AI Lab sponsored 17 undergraduates to work with faculty on yearlong research projects through MIT’s Advanced Undergraduate Research Opportunities Program (SuperUROP).

Students got to explore AI applications in climate science, finance, cybersecurity, and natural language processing, among other fields. And faculty got to work with students from outside their departments, an experience they describe in glowing terms. “Adeline is a shining testament of the value of the UROP program,” says Raffaele Ferrari, a professor in MIT’s Department of Earth and Planetary Sciences, of his advisee. “Without UROP, an oceanography professor might have never had the opportunity to collaborate with a student in computer science.”

Highlighted below are four SuperUROP projects from this past year.

A faster algorithm to manage cloud-computing jobs

The shift from desktop computing to far-flung data centers in the “cloud” has created bottlenecks for companies selling computing services. Faced with a constant flux of orders and cancellations, their profits depend heavily on efficiently pairing machines with customers.

Approximation algorithms are used to carry out this feat of optimization. Among all the possible ways of assigning machines to customers by price and other criteria, they find a schedule that achieves near-optimal profit.​ For the last year, junior Spencer Compton worked on a virtual whiteboard with MIT Professor Ronitt Rubinfeld and postdoc Slobodan Mitrović to find a faster scheduling method.

“We didn’t write any code,” he says. “We wrote proofs and used mathematical ideas to find a more efficient way to solve this optimization problem. The same ideas that improve cloud-computing scheduling can be used to assign flight crews to planes, among other tasks.”

In a pre-print paper on arXiv, Compton and his co-authors show how to speed up an approximation algorithm under dynamic conditions. They also show how to locate machines assigned to individual customers without computing the entire schedule.

A big challenge was finding the crux of the project, he says. “There’s a lot of literature out there, and a lot of people who have thought about related problems. It was fun to look at everything that’s been done and brainstorm to see where we could make an impact.”​

How much heat and carbon can the oceans absorb?

Earth’s oceans regulate climate by drawing down excess heat and carbon dioxide from the air. But as the oceans warm, it’s unclear if they will soak up as much carbon as they do now. A slowed uptake could bring about more warming than what today’s climate models predict. It’s one of the big questions facing climate modelers as they try to refine their predictions for the future.

The biggest obstacle in their way is the complexity of the problem: today’s global climate models lack the computing power to get a high-resolution view of the dynamics influencing key variables like sea-surface temperatures. To compensate for the lost accuracy, researchers are building surrogate models to approximate the missing dynamics without explicitly solving for them.

In a project with MIT Professor Raffaele Ferrari and research scientist Andre Souza, MIT junior Adeline Hillier is exploring how deep learning solutions can be used to improve or replace physical models of the uppermost layer of ocean, which drives the rate of heat and carbon uptake. “If the model has a small footprint and succeeds under many of the physical conditions encountered in the real world, it could be incorporated into a global climate model and hopefully improve climate projections,” she says.

In the course of the project, Hillier learned how to code in the programming language Julia. She also got a crash course in fluid dynamics. “You’re trying to model the effects of turbulent dynamics in the ocean,” she says. “It helps to know what the processes and physics behind them look like.”

In search of more efficient deep learning models

There are thousands of ways to design a deep learning model to solve a given task. Automating the design process promises to narrow the options and make these tools more accessible. But finding the optimal architecture is anything but simple. Most automated searches pick the model that maximizes validation accuracy without considering the structure of the underlying data, which may suggest a simpler, more robust solution. As a result, more reliable or data-efficient architectures are passed over.

“Instead of looking at the accuracy of the model alone, we should focus on the structure of the data,” says MIT senior Kristian Georgiev. In a project with MIT Professor Asu Ozdaglar and graduate student Alireza Fallah, Georgiev is looking at ways to automatically query the data to find the model that best suits its constraints. “If you choose your architecture based on the data, you’re more likely to get a good and robust solution from a learning theory perspective,” he says.

The hardest part of the project was the exploratory phase at the start, he says. To find a good research question he read through papers ranging from topics in autoML to representation theory. But it was worth it, he says, to be able to work at the intersection of optimization and generalization. “To make good progress in machine learning you need to combine both of these fields.”

What makes humans so good at recognizing faces?

Face recognition comes easily to humans. Picking out familiar faces in a blurred or distorted photo is a cinch. But we don’t really understand why or how to replicate this superpower in machines. To home in on the principles important to recognizing faces, researchers have shown headshots to human subjects that are progressively degraded to see where recognition starts to break down. They are now performing similar experiments on computers to see if deeper insights can be gained

In a project with MIT Professor Pawan Sinha and the MIT Quest for Intelligence, junior Ashika Verma applied a set of filters to a dataset of celebrity photos. She blurred their faces, distorted them, and changed their color to see if a face-recognition model could pick out photos of the same face. She found that the model did best when the photos were either natural color or grayscale, consistent with the human studies. Accuracy slipped when a color filter was added, but not as much as it did for the human subjects — a wrinkle that Verma plans to investigate further.

The work is part of a broader effort to understand what makes humans so good at recognizing faces, and how machine vision might be improved as a result. It also ties in with Project Prakash, a nonprofit in India that treats blind children and tracks their recovery to learn more about the visual system and brain plasticity. “Running human experiments takes more time and resources than running computational experiments,” says Verma’s advisor, Kyle Keane, a researcher with MIT Quest. “We’re trying to make AI as human-like as possible so we can run a lot of computational experiments to identify the most promising experiments to run on humans.”

Degrading the images to use in the experiments, and then running them through the deep nets, was a challenge, says Verma. “It’s very slow,” she says. “You work 20 minutes at a time and then you wait.” But working in a lab with an advisor made it worth it, she says. “It was fun to dip my toes into neuroscience.”

SuperUROP projects were funded, in part, by the MIT-IBM Watson AI Lab, MIT Quest Corporate, and by Eric Schmidt, technical advisor to Alphabet Inc., and his wife, Wendy. More

The winners of this year’s Rabobank-MIT Food and Agribusiness Innovation Prize got a good indication their pitch was striking a chord when a judge offered to have his company partner with the team for an early demonstration. The offer signified demand for their solution — to say nothing of their chances of winning the pitch competition.

The annual competition’s MIT-based grand-prize winner, Human Dynamics, is seeking to improve sanitation in food production plants with a robotic drone — a “drobot” — that flies through facilities spraying soap and disinfectant.

The company says the product addresses major labor shortages for food production facilities, which often must carry out daily sanitation processes.

“They have to sanitize every night, and it’s extremely labor intensive and expensive,” says co-founder Tom Okamoto, a master’s student in MIT’s System Design and Management (SDM) program.

In the winning pitch, Okamoto said the average large food manufacturer spends $13 million on sanitation annually. When you combine the time sanitation processes takes away from production and delays due to human error, Human Dynamics estimates it’s tackling an $80 billion problem.

The company’s prototype uses a quadcopter drone that carries a tank, nozzle, and spray hose. Underneath the hood, the drone uses visual detection technology to validate that each area is clean, LIDAR to map out its path, and algorithms for route optimization.

The product is designed to automate repetitive tasks while complementing other cleaning efforts currently done by humans. Workers will still be required for certain aspects of cleaning and tasks like preparing and inspecting facilities during sanitation.

The company has already developed several proofs of concept and is planning to run a pilot project with a local food producer and distributor this summer.

The Human Dynamics team also includes MIT researcher Takahiro Nozaki, MIT master’s student Julia Chen, and Harvard Business School students Mike Mancinelli and Kaz Yoshimaru.

The company estimates that the addressable market for sanitation in food production facilities in the country is $3 billion.

The second-place prize went to Resourceful, which aims to help connect buyers and sellers of food waste byproducts through an online platform. The company says there’s a growing market for upcycled products made by companies selling things like edible chips made from juice pulp, building materials made from potato skins, and eyeglasses made from orange peels. But establishing a byproduct supply chain can be difficult.

“Being paid for byproducts should be low-hanging fruit for food manufacturers, but the system is broken,” says co-founder and CEO Kyra Atekwana, an MBA candidate at the University of Chicago’s Booth School of Business. “There are tens of millions of pounds of food waste produced in the U.S. every year, and there’s a variety of tech solutions … enabling this food waste and surplus to be captured by consumers. But there’s virtually nothing in the middle to unlock access to the 10.6 million tons of byproduct waste produced every year.”

Buyers and sellers can offer and browse food waste byproducts on the company’s subscription-based platform. The businesses can also connect and establish contracts through the platform. Resourceful charges a small fee for each transaction.

The company is currently launching pilots in the Chicago region before making a public launch later this year. It has also partnered with the Upcycled Food Association, a nonprofit focused on reducing food waste.

The winners were chosen from a group of seven finalist teams. Other finalists included:

Chicken Haus, a vertically integrated, fast-casual restaurant concept dedicated to serving locally sourced, bone-in fried chicken;
Joise Food Technologies, which is 3-D printing the next-generation of meat alternatives and other foods using 3-D biofabrication technology and sustainable food ink formulation;
Marble, which is developing a small-footprint robot to remove fat from the surface of meat cuts to achieve optimal yield;
Nice Rice, which is developing a rice alternative made from pea starch, which can be upcycled; and
Roofscapes, which deploys accessible wooden platforms to “vegetalize” roofs in dense urban areas to combat food insecurity and climate change.

This was the sixth year of the event, which was hosted by the MIT Food and Agriculture Club. The event was sponsored by Rabobank and MIT’s Abdul Latif Jameel World Water and Food Systems Lab (J-WAFS). More

Nearly one quarter of the land in the Northern Hemisphere, amounting to some 9 million square miles, is layered with permafrost — soil, sediment, and rocks that are frozen solid for years at a time. Vast stretches of permafrost can be found in Alaska, Siberia, and the Canadian Arctic, where persistently freezing temperatures have kept carbon, in the form of decayed bits of plants and animals, locked in the ground.

Scientists estimate that more than 1,400 gigatons of carbon is trapped in the Earth’s permafrost. As global temperatures climb, and permafrost thaws, this frozen reservoir could potentially escape into the atmosphere as carbon dioxide and methane, significantly amplifying climate change. However, little is known about permafrost’s stability, today or in the past.

Now geologists at MIT, Boston College, and elsewhere have reconstructed permafrost’s history over the last 1.5 million years. The researchers analyzed cave deposits in locations across western Canada and found evidence that, between 1.5 million and 400,000 years ago, permafrost was prone to thawing, even in high Arctic latitudes. Since then, however, permafrost thaw has been limited to sub-Arctic regions.

The results, published today in Science Advances, suggest that the planet’s permafrost shifted to a more stable state in the last 400,000 years, and has been less susceptible to thawing since then. In this more stable state, permafrost likely has retained much of the carbon that it has built up during this time, having little opportunity to gradually release it.

“The stability of the last 400,000 years may actually work against us, in that it has allowed carbon to steadily accumulate in permafrost over this time. Melting now might lead to substantially greater releases of carbon to the atmosphere than in the past,” says study co-author David McGee, associate professor in MIT’s Department of Earth, Atmospheric, and Planetary Sciences.

McGee’s co-authors are Ben Hardt and Irit Tal at MIT; Nicole Biller-Celander, Jeremy Shakun, and Corinne Wong at Boston College; Alberto Reyes at the University of Alberta; Bernard Lauriol at the University of Ottawa; and Derek Ford at McMaster University.

Stacked warming

Periods of past warming are considered interglacial periods, or times between global ice ages. These geologically brief windows can warm permafrost enough to thaw. Signs of ancient permafrost thaw can be seen in stalagmites and other mineral deposits left behind as water moves through the ground and into caves. These caves, particularly at high Arctic latitudes, are often remote and difficult to access, and as a result, there has been little known about the history of permafrost, and its past stability in warming climates.

However, in 2013, researchers at Oxford University were able to sample cave deposits from a few locations across Siberia; their analysis suggested that permafrost thaw was widespread throughout Siberia prior to 400,000 years ago. Since then, the results showed a much-reduced range of permafrost thaw.

Shakun and Biller-Celander wondered whether the trend toward a more stable permafrost was a global one, and looked to carry out similar studies in Canada to reconstruct the permafrost history there. They linked up with pioneering cave scientists Lauriol and Ford, who provided samples of cave deposits that they collected over the years from three distinct permafrost regions: the southern Canadian Rockies, Nahanni National Park in the Northwest Territories, and the northern Yukon.

In total, the team obtained 74 samples of speleothems, or sections of stalagmites, stalactites, and flowstones, from at least five caves in each region, representing various cave depths, geometries, and glacial histories. Each sampled cave was located on exposed slopes that were likely the first parts of the permafrost landscape to thaw with warming.

The samples were flown to MIT, where McGee and his lab used precise geochronology techniques to determine the ages of each sample’s layers, each layer reflecting a period of permafrost thaw.

“Each speleothem was deposited over time like stacked traffic cones,” says McGee. “We started with the outermost, youngest layers to date the most recent time that the permafrost thawed.”

Arctic shift

McGee and his colleagues used techniques of uranium/thorium geochronology to date the layers of each speleothem. The dating technique relies on the natural decay process of uranium to its daughter isotope, thorium 230, and the fact that uranium is soluble in water, whereas thorium is not.

“In the rocks above the cave, as waters percolate through, they accumulate uranium and leave thorium behind,” McGee explains. “Once that water gets to the stalagmite surface and precipitates at time zero, you have uranium, and no thorium. Then gradually, uranium decays and produces thorium.”

The team drilled out small amounts from each sample and dissolved them through various chemical steps to isolate uranium and thorium. Then they ran the two elements through a mass spectrometer to measure their amounts, the ratio of which they used to calculate a given layer’s age.

From their analysis, the researchers observed that samples collected from the Yukon and the farthest northern sites bore samples no younger than 400,000 years old, suggesting permafrost thaw has not occurred in those sites since then.

“There may have been some shallow thaw, but in terms of the entire rock above the cave being thawed, that hasn’t occurred for the last 400,000 years, and was much more common prior to that,” McGee says.

The results suggest that the Earth’s permafrost was much less stable prior to 400,000 years ago and was more prone to thawing, even during interglacial periods when levels of temperature and atmospheric carbon dioxide were on par with modern levels, as other work has shown.

“To see this evidence of a much less stable Arctic prior to 400,000 years ago, suggests even under similar conditions, the Arctic can be a very different place,” McGee says. “It raises questions for me about what caused the Arctic to shift into this more stable condition, and what can cause it to shift out of it.”

This research was supported, in part, by the National Science Foundation, the National Sciences and Engineering Research Council of Canada, and the Polar Continental Shelf Program. More

MIT is uniquely positioned to lead the way on the technological advances and policy options needed to address climate change. At the second MIT Climate Engagement Forum of the semester, students, faculty, alumni, and staff described the many ways they are engaging an array of organizations to bring real solutions to the climate crisis. Several participants in the discussion offered suggestions from their own personal and professional experiences on how the Institute can make tackling the climate crisis part of its core mission. “The problems are too big and too interconnected for any institution, even this one, to solve alone,” said Maria Zuber, MIT’s vice president for research, in opening remarks.

As MIT prepares to release its second Plan for Action on Climate Change this spring, the Office of the Vice President for Research is taking stock of the Institute’s climate progress to date. The forum, hosted by the Environmental Solutions Initiative (ESI), brought together a diverse group: seniors Kiara Wahnshafft and Megan Guenther, graduate students Pervez Agwan and Caroline White-Nockleby, alumni Lucy Milde and Gail Greenwald, MIT Corporation member Diana Chapman-Walsh, Senior Associate Dean Kate Trimble, and faculty members Megan Black, Desiree Plata, Timothy Gutowski, and John E. Fernandez.

Supporting students to ensure an “all of MIT” approach

MIT is known for providing students with hands-on training through experiential learning opportunities and internships. Industry leaders are increasingly recognizing the value of having technically skilled employees who can also navigate the messiness of real-world problem-solving, said John Fernández, director of ESI.

“There are a growing number of companies who see that one of the obstacles to a sustainable future for them is they don’t have the workforce to get there,” Fernández said. “I think this is an extraordinary opportunity for us.”

Similarly, Kate Trimble, director of the Office of Experiential Learning, told forum attendees that sustainability should be the “crown jewel” of an MIT education. “I imagine a world where sustainability really permeates everything that we do, and sustainability is something that students have to go out of their way to avoid, as opposed to specially seeking it out,” Trimble said. To do that, MIT needs to provide more opportunities for students to develop “change-making skills,” she said, and reflect on what they’re learning out in the field during internships.

Timothy Gutowski, an MIT professor of engineering, described the hands-on class he co-teaches called “Solving for carbon neutrality at MIT.” Diving deep into MIT’s own emissions has given him a new perspective on the obstacles to carbon neutrality, both on campus and in the wider world. “Quite frankly, they often turn out to be people — human behavior, how we get along, how we cooperate, how we solve problems.”

Pervez Agwan, an MBA candidate and president of the MIT Energy Club, said that he has found a community of like-minded students working on energy problems. But the Institute should do a better job of instilling in all students that MIT stands for sustainability and climate action. “It’s not because they don’t have an interest,” he said. “They just don’t know what’s happening, and it’s not part of our culture.”

Engaging outside of MIT

One of the pillars of MIT’s 2015 Plan for Action on Climate Change is to better educate government and industry leaders on climate change. Senior Kiara Wahnschafft remarked that she worked on Massachusetts’ recent climate bill as part of an internship she did with the Environmental Solution Initiative’s Rapid Response Group. The Institute should scale up those partnerships so that policymakers know to turn to MIT for scientifically-sound climate research. “In my ideal world, MIT is the climate policymaking hub,” she said.

A key component of that will be continually evaluating what successful engagement with partners looks like, said Gail Greenwald ‘75, a board member of Launchpad Venture Group. Similar to how MIT tracks its emissions reductions project, the Institute needs to ensure its partnerships advance decarbonization off-campus. “We don’t have time to rest on our laurels or to be participating in greenwashing,” she said.

At the same time, meeting attendees stressed that MIT should not shy away from working with companies that have less-than-sterling reputations on climate change. “It doesn’t have to be an ‘all or nothing’ approach,” said Wahnschafft. “We can have a great relationship with a company and do research or some other kind of partnership, and still say we disagree with their current tax bill in Washington.”

Lucy Milde ’20 called on MIT to weave ethical considerations into its work around climate mitigation and adaptation. “I think the MIT education is kind of lacking in the area of making sure that we’re empowering marginalized communities,” and ensuring that graduates carry those considerations forward into their careers, she said.

To do that, the Institute should incorporate community engagement and climate justice into its next plan, stressed Caroline White-Nockleby, a graduate student in MIT’s Doctoral Program in History, Anthropology, and Science, Technology, and Society. MIT is “well-positioned” to facilitate energy transition conversations between residents, employers, and local and state officials, she added.

White-Nockleby noted that places facing climate impacts are often dealing with other economic or environmental challenges. For example, in a western Pennsylvania county where she and other Environmental Solutions Initiative interns researched the economic impacts of coal’s decline, residents are primarily concerned about job losses and tax cuts. “There’s a lot of ways to engage communities around climate change by engaging in the values that matter to those communities,” White-Nockleby said.

Facing uncertainty head-on

The forum closed with a panel on how to deal with uncertainty — the topic of a new effort called the “Council on the Uncertain Human Future” at MIT and other universities. Diana Chapman Walsh, a member of the council’s leadership team, said that anxiety and dread can hinder meaningful conversations around climate change. “So our intention for the council was and is to hold a space for a very different conversation than usual,” she explained, “where participants look deeply and personally into the reality of situation as best we can understand it” with others ready to commit to an “honest reckoning” with the climate emergency.

Desiree Plata, an associate professor of in MIT’s Department of Civil and Environmental Engineering, said her initial skepticism about joining the council went away when she saw other participants become more optimistic over the course of weekly meetings. “People need mechanisms for healing in this time, especially, and that healing can impart motivation,” she said.

Megan Black, an associate professor of history at MIT, pointed to the massive infrastructure building and conservation work done in the United States in response to the Great Depression as an inspiration for how to deal with present-day uncertainties. “In moments of crisis, people have come together even though it was highly uncertain how it would turn out, and tried to forge a meaningful response,” she said.

Senior Megan Guenther, echoing that, said that although, “there is a lot of uncertainty regarding what is going on with the climate, there are a ton of opportunities available — really, endless opportunities — for how we can address this issue.”

In closing remarks, Associate Provost for International Activities Richard Lester highlighted the “whole-of-MIT” approach as integral to its expanding commitment to the climate challenge. “This institution, more than most, has the capacity and therefore the responsibility to contribute” to addressing the climate emergency, he said. “And it seems to me that the question that we should always be asking ourselves is, how can we make our institution stronger and better able to contribute, where we can have the greatest impact?” More

There is a lot of activity beneath the vast, lonely expanses of ice and snow in the Arctic. Climate change has dramatically altered the layer of ice that covers much of the Arctic Ocean. Areas of water that used to be covered by a solid ice pack are now covered by thin layers only 3 feet deep. Beneath the ice, a warm layer of water, part of the Beaufort Lens, has changed the makeup of the aquatic environment.    

For scientists to understand the role this changing environment in the Arctic Ocean plays in global climate change, there is a need for mapping the ocean below the ice cover.

A team of MIT engineers and naval officers led by Henrik Schmidt, professor of mechanical and ocean engineering, is trying to understand environmental changes, their impact on acoustic transmission beneath the surface, and how these changes affect navigation and communication for vehicles traveling below the ice.

“Basically, what we want to understand is how does this new Arctic environment brought about by global climate change affect the use of underwater sound for communication, navigation, and sensing?” explains Schmidt.

To answer this question, Schmidt traveled to the Arctic with members of the Laboratory for Autonomous Marine Sensing Systems (LAMSS) including Daniel Goodwin and Bradli Howard, graduate students in the MIT-Woods Hole Oceanographic Institution Joint Program in oceanographic engineering.

With funding from the Office of Naval Research, the team participated in ICEX — or Ice Exercise — 2020, a three-week program hosted by the U.S. Navy, where military personnel, scientists, and engineers work side-by-side executing a variety of research projects and missions.

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Understanding the Arctic | MIT MechE

A strategic waterway

The rapidly changing environment in the Arctic has wide-ranging impacts. In addition to giving researchers more information about the impact of global warming and the effects it has on marine mammals, the thinning ice could potentially open up new shipping lanes and trade routes in areas that were previously untraversable.

Perhaps most crucially for the U.S. Navy, understanding the altered environment also has geopolitical importance.

“If the Arctic environment is changing and we don’t understand it, that could have implications in terms of national security,” says Goodwin.

Several years ago, Schmidt and his colleague Arthur Baggeroer, professor of mechanical and ocean engineering, were among the first to recognize that the warmer waters, part of the Beaufort Lens, coupled with the changing ice composition, impacted how sound traveled in the water.

To successfully navigate throughout the Arctic, the U.S. Navy and other entities in the region need to understand how these changes in sound propagation affect a vehicle’s ability to communicate and navigate through the water.

Using an unpiloted, autonomous underwater vehicle (AUV) built by General Dynamics-Mission Systems (GD-MS), and a system of sensors rigged on buoys developed by the Woods Hole Oceanographic Institution, Schmidt and his team, joined by Dan McDonald and Josiah DeLange of GD-MS, set out to demonstrate a new integrated acoustic communication and navigation concept.

The framework, which was also supported and developed by LAMSS members Supun Randeni, EeShan Bhatt, Rui Chen, and Oscar Viquez, as well as LAMSS alumnus Toby Schneider of GobySoft LLC, would allow vehicles to travel through the water with GPS-level accuracy while employing oceanographic sensors for data collection.

“In order to prove that you can use this navigational concept in the Arctic, we have to first ensure we fully understand the environment that we’re operating in,” adds Goodwin.

Understanding the environment belowAfter arriving at the Arctic Submarine Lab’s ice camp last spring, the research team deployed a number of conductivity-temperature-depth probes to gather data about the aquatic environment in the Arctic.

“By using temperature and salinity as a function of depth, we calculate the sound speed profile. This helps us understand if the AUV’s location is good for communication or bad,” says Howard, who was responsible for monitoring environmental changes to the water column throughout ICEX.

Because of the way sound bends in water, through a concept known as Snell’s Law, sine-like pressure waves collect in some parts of the water column and disperse in others. Understanding the propagation trajectories is key to predicting good and bad locations for the AUV to operate.  

To map the areas of the water with optimal acoustic properties, Howard modified the traditional signal-to-noise-ratio (SNR) by using a metric known as the multi-path penalty (MPP), which penalizes areas where the AUV receives echoes of the messages. As a result, the vehicle prioritizes operations in areas with less reverb.

These data allowed the team to identify exactly where the vehicle should be positioned in the water column for optimal communications which results in accurate navigation.

While Howard gathered data on how the characteristics of the water impact acoustics, Goodwin focused on how sound is projected and reflected off the ever-changing ice on the surface.

To get these data, the AUV was outfitted with a device that measured the motion of the vehicle relative to the ice above. That sound was picked up by several receivers attached to moorings hanging from the ice.

The data from the vehicle and the receivers were then used by the researchers to compute exactly where the vehicle was at a given time. This location information, together with the data Howard gathered on the acoustic environment in the water, offer a new navigational concept for vehicles traveling in the Arctic Sea.

Protecting the Arctic

After a series of setbacks and challenges due to the unforgiving conditions in the Arctic, the team was able to successfully prove their navigational concept worked. Thanks to the team’s efforts, naval operations and future trade vessels may be able to take advantage of the changing conditions in the Arctic to maximize navigational accuracy and improve underwater communications.

“Our work could improve the ability for the U.S. Navy to safely and effectively operate submarines under the ice for extended periods,” Howard says.

Howard acknowledges that in addition to the changes in physical climate, the geopolitical climate continues to change. This only strengthens the need for improved navigation in the Arctic.

“The U.S. Navy’s goal is to preserve peace and protect global trade by ensuring freedom of navigation throughout the world’s oceans,” she adds. “The navigational concept we proved during ICEX will serve to help the Navy in that mission.” More

MIT students Spencer Compton, Karna Morey, Tara Venkatadri, and Lily Zhang have been selected to receive a Barry Goldwater Scholarship for the 2021-22 academic year. Over 5,000 college students from across the United States were nominated for the scholarships, from which only 410 recipients were selected based on academic merit. 

The Goldwater scholarships have been conferred since 1989 by the Barry Goldwater Scholarship and Excellence in Education Foundation. These scholarships have supported undergraduates who go on to become leading scientists, engineers, and mathematicians in their respective fields. All of the 2021-22 Goldwater Scholars intend to obtain a doctorate in their area of research, including the four MIT recipients. 

Spencer Compton

A junior majoring in computer science and engineering, Compton is set to graduate next year with both his undergraduate and master’s degrees. For Compton, solving advanced problems is as fun as it is challenging — he’s been involved in algorithm competitions since high school, where, on the U.S. team for the 2018 International Olympiad in Informatics, Compton won gold. “I still participate — there’s a college equivalent, the Intercollegiate Programming Contest or ICPC, and I’m on last year’s MIT team that won first in North America,” reports Compton. “We were supposed to represent MIT in the World Finals in Russia last summer, but it’s been postponed due to Covid.” Compton brings his competitive and enthusiastic mindset to his areas of research, including his collaboration on causal inference with the MIT-IBM Watson AI Lab, and his work on approximation algorithms and scheduling with professor of electrical engineering and computer science Ronitt Rubinfeld and postdoc Slobodan Mitrović​.

In her recommendation letter, Rubinfeld, a member of the Computer Science and Artificial Intelligence Laboratory, spoke at length about Compton’s aptitude as a student but she also left a glowing review as to Compton’s character. “Spencer is extraordinarily pleasant to work with. He is kind and caring when he interacts with younger students. I once had a high school student follow me for a day on which I happened to have a meeting with Spencer ­­— she was so impressed with him that he became a role model for her,” wrote Rubinfeld. Following the completion of his current degrees at MIT, Compton plans to obtain his PhD in computer science, continue his research in algorithms, and teach at the university level.

Karna Morey

Morey is a third-year majoring in physics with a minor in Spanish. He got interested in physics while reading Albert Einstein’s biography in the seventh grade, and performed research for two years in high school on gravitational wave physics of a body falling into a black hole. On campus, he has been involved in physics research in theoretical and observational astrophysics, as well as in condensed matter experiments. He recently authored an accepted paper on measuring the lifetime of high-redshift quasars to better understand the ways that supermassive black holes grow. Currently, he is working in the Gedik group, exploring quantum materials using second harmonic generation. Morey plans on pursuing a PhD in physics and one day conduct research at the university level.

“It was a great experience working with Karna. He was the first student I worked with and he set the bar very high for any future students,” said Christina Eilers, a Pappalardo Fellow in the MIT Department of Physics; Eilers supervised Morey’s research estimating the timescales of supermassive black holes in the early universe and was extremely impressed by his coding skills and confidence as a researcher. Morey is also heavily involved in diversity, equity, and inclusion efforts in the physics department and in the broader field, where he serves as one of the co-chairs of the cross-constituency Physics Values Committee, which seeks to work with department leadership and stakeholders to improve the climate and culture of the physics department. He hopes to make meaningful contributions not only to further scientific discoveries, but also to making science more inclusive.

Tara Venkatadri

A fourth-generation engineer and junior at MIT, Venkatadri is following her passion for space exploration, majoring in aeronautical and astronautical engineering with a minor in Earth, atmospheric, and planetary sciences. During her time at MIT, Venkatadri became interested in aerospace structures, pointing out that the unforgiving space environment places unique spacecraft constraints, especially for crewed missions. “As we go deeper into outer space and send humans to other planets, we need to design new methods and materials to ensure the safety of astronauts when pursuing increasingly ambitious space exploration,” she said.

Her interest in aerospace structures eventually landed her in the lab of Professor Tal Cohen, the Robert N. Noyce Career Development Professor and assistant professor of civil and environmental engineering and mechanical engineering. Venkatadri is trying to understand how adhesive materials deform under torsion in order to use them safely and efficiently in real-world structures, such as spacecraft. There has been increasing interest in adhesives across many industries because they can bond dissimilar materials together without welding and do not concentrate stress on the materials the way mechanical fastenings like bolts and rivets do. In his letter of recommendation, Olivier de Weck, a professor of aeronautics and astronautics and of engineering systems at MIT, cited Venkatadri’s research rigor, academic scholarship, and significant acts of service to the department, noting “without hesitation that Tara is the most impressive undergraduate student I have seen in our department over the last decade.”

Lily Zhang

Zhang is a junior double-majoring in Earth, atmospheric, and planetary sciences as well as physics, with minors in public policy and math. Zhang has a passion for climate science, something she’s known since she first viewed Al Gore’s “An Inconvenient Truth” as a child. That passion was encouraged by her father, a professor of meteorology. “He was really passionate about his research and loved his job, which helped me develop my own appreciation for science and academia,” says Zhang. Though her father passed away in 2019, Zhang says he remains a major inspiration on her life.

At MIT, Zhang is now in the finishing stages of two of her own research projects, including using satellite observations to fill in the historic Halley ozone record with Professor Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies in the Department of Earth, Atmospheric and Planetary Sciences. “Lily never ceases to astonish me with her ability to tackle research questions and come up with clever solutions. The Goldwater scholarship is fitting recognition of her enormous potential,” said Solomon. Zhang is thankful to all of her mentors, both past and present, and says that the opportunity to work alongside them and observe their research approaches first-hand has been a dream. After finishing her undergraduate degree, Zhang aims to obtain her PhD and bring her zest for education and research as a professor in climate science.

The Barry Goldwater Scholarship and Excellence in Education Program was established by Congress in 1986 to honor Senator Barry Goldwater, a soldier and national leader who served the country for 56 years. Awardees receive scholarships of up to $7,500 a year to cover costs related to tuition, room and board, fees, and books. More

Since its invention several millennia ago, concrete has become instrumental to the advancement of civilization, finding use in countless construction applications — from bridges to buildings. And yet, despite centuries of innovation, its function has remained primarily structural.

A multiyear effort by MIT Concrete Sustainability Hub (CSHub) researchers, in collaboration with the French National Center for Scientific Research (CNRS), has aimed to change that. Their collaboration promises to make concrete more sustainable by adding novel functionalities — namely, electron conductivity. Electron conductivity would permit the use of concrete for a variety of new applications, ranging from self-heating to energy storage.

Their approach relies on the controlled introduction of highly conductive nanocarbon materials into the cement mixture. In a paper in Physical Review Materials, they validate this approach while presenting the parameters that dictate the conductivity of the material. 

Nancy Soliman, the paper’s lead author and a postdoc at the MIT CSHub, believes that this research has the potential to add an entirely new dimension to what is already a popular construction material.

“This is a first-order model of the conductive cement,” she explains. “And it will bring [the knowledge] needed to encourage the scale-up of these kinds of [multifunctional] materials.” 

From the nanoscale to the state-of-the-art

Over the past several decades, nanocarbon materials have proliferated due to their unique combination of properties, chief among them conductivity. Scientists and engineers have previously proposed the development of materials that can impart conductivity to cement and concrete if incorporated within.

For this new work, Soliman wanted to ensure the nanocarbon material they selected was affordable enough to be produced at scale. She and her colleagues settled on nanocarbon black — a cheap carbon material with excellent conductivity. They found that their predictions of conductivity were borne out.

“Concrete is naturally an insulative material,” says Soliman, “But when we add nanocarbon black particles, it moves from being an insulator to a conductive material.”

By incorporating nanocarbon black at just a 4 percent volume of their mixtures, Soliman and her colleagues found that they could reach the percolation threshold, the point at which their samples could carry a current.

They noticed that this current also had an interesting upshot: It could generate heat. This is due to what’s known as the Joule effect.

“Joule heating (or resistive heating) is caused by interactions between the moving electrons and atoms in the conductor, explains Nicolas Chanut, a co-author on the paper and a postdoc at MIT CSHub. “The accelerated electrons in the electric field exchange kinetic energy each time they collide with an atom, inducing vibration of the atoms in the lattice, which manifests as heat and a rise of temperature in the material.”

In their experiments, they found that even a small voltage — as low as 5 volts — could increase the surface temperatures of their samples (approximately 5 cm3 in size) up to 41 degrees Celsius (around 100 degrees Fahrenheit). While a standard water heater might reach comparable temperatures, it’s important to consider how this material would be implemented when compared to conventional heating strategies.

“This technology could be ideal for radiant indoor floor heating,” explains Chanut. “Usually, indoor radiant heating is done by circulating heated water in pipes that run below the floor. But this system can be challenging to construct and maintain. When the cement itself becomes a heating element, however, the heating system becomes simpler to install and more reliable. Additionally, the cement offers more homogenous heat distribution due to the very good dispersion of the nanoparticles in the material.”

Nanocarbon cement could have various applications outdoors, as well. Chanut and Soliman believe that if implemented in concrete pavements, nanocarbon cement could mitigate durability, sustainability, and safety concerns. Much of those concerns stem from the use of salt for de-icing.

“In North America, we see lots of snow. To remove this snow from our roads requires the use of de-icing salts, which can damage the concrete, and contaminate groundwater,” notes Soliman. The heavy-duty trucks used to salt roads are also both heavy emitters and expensive to run.

By enabling radiant heating in pavements, nanocarbon cement could be used to de-ice pavements without road salt, potentially saving millions of dollars in repair and operations costs while remedying safety and environmental concerns. In certain applications where maintaining exceptional pavement conditions is paramount — such as airport runways — this technology could prove particularly advantageous.       

Tangled wires

While this state-of-the-art cement offers elegant solutions to an array of problems, achieving multifunctionality posed a variety of technical challenges. For instance, without a way to align the nanoparticles into a functioning circuit — known as the volumetric wiring — within the cement, their conductivity would be impossible to exploit. To ensure an ideal volumetric wiring, researchers investigated a property known as tortuosity.

“Tortuosity is a concept we introduced by analogy from the field of diffusion,” explains Franz-Josef Ulm, a leader and co-author on the paper, a professor in the MIT Department of Civil and Environmental Engineering, and the faculty advisor at CSHub. “In the past, it has described how ions flow. In this work, we use it to describe the flow of electrons through the volumetric wire.”

Ulm explains tortuosity with the example of a car traveling between two points in a city. While the distance between those two points as the crow flies might be two miles, the actual distance driven could be greater due to the circuity of the streets.

The same is true for the electrons traveling through cement. The path they must take within the sample is always longer than the length of the sample itself. The degree to which that path is longer is the tortuosity.

Achieving the optimal tortuosity means balancing the quantity and dispersion of carbon. If the carbon is too heavily dispersed, the volumetric wiring will become sparse, leading to high tortuosity. Similarly, without enough carbon in the sample, the tortuosity will be too great to form a direct, efficient wiring with high conductivity.

Even adding large amounts of carbon could prove counterproductive. At a certain point conductivity will cease to improve and, in theory, would only increase costs if implemented at scale. As a result of these intricacies, they sought to optimize their mixes.

“We found that by fine-tuning the volume of carbon we can reach a tortuosity value of 2,” says Ulm. “This means the path the electrons take is only twice the length of the sample.”

Quantifying such properties was vital to Ulm and his colleagues. The goal of their recent paper was not just to prove that multifunctional cement was possible, but that it was also viable for mass production.

“The key point is that in order for an engineer to pick up things, they need a quantitative model,” explains Ulm. “Before you mix materials together, you want to be able to expect certain repeatable properties. That’s exactly what this paper outlines; it separates what is due to boundary conditions — [extraneous] environmental conditions — from really what is due to the fundamental mechanisms within the material.”

By isolating and quantifying these mechanisms, Soliman, Chanut, and Ulm hope to provide engineers with exactly what they need to implement multifunctional cement on a broader scale. The path they’ve charted is a promising one — and, thanks to their work, shouldn’t prove too tortuous.

The research was supported through the Concrete Sustainability Hub by the Portland Cement Association and the Ready Mixed Concrete Research and Education Foundation. More