MIT News - School of Science

Two projects receive funding for technologies that avoid carbon emissions

Emily Dahl | MIT Energy Initiative — Thu, 20 Aug 2020 14:00:01 -0400

The Carbon Capture, Utilization, and Storage Center, one of the MIT Energy Initiative (MITEI)’s Low-Carbon Energy Centers, has awarded $900,000 in funding to two new research projects to advance technologies that avoid carbon dioxide (CO₂) emissions into the atmosphere and help address climate change. The winning project is receiving $750,000, and an additional project receives $150,000.

The winning project, led by principal investigator Asegun Henry, the Robert N. Noyce Career Development Professor in the Department of Mechanical Engineering, and co-principal investigator Paul Barton, the Lammot du Pont Professor of Chemical Engineering, aims to produce hydrogen without CO₂ emissions while creating a second revenue stream of solid carbon. The additional project, led by principal investigator Matěj Peč, the Victor P. Starr Career Development Chair in the Department of Earth, Atmospheric and Planetary Sciences, seeks to expand understanding of new processes for storing CO₂ in basaltic rocks by converting it from an aqueous solution into carbonate minerals.

Carbon capture, utilization, and storage (CCUS) technologies have the potential to play an important role in limiting or reducing the amount of CO₂ in the atmosphere, as part of a suite of approaches to mitigating to climate change that includes renewable energy and energy efficiency technologies, as well as policy measures. While some CCUS technologies are being deployed at the million-ton-of-CO₂ per year scale, there are substantial needs to improve costs and performance of those technologies and to advance more nascent technologies. MITEI’s CCUS center is working to meet these challenges with a cohort of industry members that are supporting promising MIT research, such as these newly funded projects.

A new process for producing hydrogen without CO₂ emissions

Henry and Barton’s project, “Lower cost, CO₂-free, H₂ production from CH₄ using liquid tin,” investigates the use of methane pyrolysis instead of steam methane reforming (SMR) for hydrogen production.

Currently, hydrogen production accounts for approximately 1 percent of global CO₂ emissions, and the predominant production method is SMR. The SMR process relies on the formation of CO₂, so replacing it with another economically competitive approach to making hydrogen would avoid emissions.

“Hydrogen is essential to modern life, as it is primarily used to make ammonia for fertilizer, which plays an indispensable role in feeding the world’s 7.5 billion people,” says Henry. “But we need to be able to feed a growing population and take advantage of hydrogen’s potential as a carbon-free fuel source by eliminating CO₂ emissions from hydrogen production. Our process results in a solid carbon byproduct, rather than CO₂ gas. The sale of the solid carbon lowers the minimum price at which hydrogen can be sold to break even with the current, CO₂ emissions-intensive process.”

Henry and Barton’s work is a new take on an existing process, pyrolysis of methane. Like SMR, methane pyrolysis uses methane as the source of hydrogen, but follows a different pathway. SMR uses the oxygen in water to liberate the hydrogen by preferentially bonding oxygen to the carbon in methane, producing CO₂ gas in the process. In methane pyrolysis, the methane is heated to such a high temperature that the molecule itself becomes unstable and decomposes into hydrogen gas and solid carbon — a much more valuable byproduct than CO₂ gas. Although the idea of methane pyrolysis has existed for many years, it has been difficult to commercialize because of the formation of the solid byproduct, which can deposit on the walls of the reactor, eventually plugging it up. This issue makes the process impractical. Henry and Barton’s project uses a new approach in which the reaction is facilitated with inert molten tin, which prevents the plugging from occurring. The proposed approach is enabled by recent advances in Henry’s lab that enable the flow and containment of liquid metal at extreme temperatures without leakage or material degradation.

Studying CO₂ storage in basaltic reservoirs

With his project, “High-fidelity monitoring for carbon sequestration: integrated geophysical and geochemical investigation of field and laboratory data,” Peč plans to conduct a comprehensive study to gain a holistic understanding of the coupled chemo-mechanical processes that accompany CO₂ storage in basaltic reservoirs, with hopes of increasing adoption of this technology.

The Intergovernmental Panel on Climate Change estimates that 100 to 1,000 gigatonnes of CO₂ must be removed from the atmosphere by the end of the century. Such large volumes can only be stored below the Earth’s surface, and that storage must be accomplished safely and securely, without allowing any leakage back into the atmosphere.

One promising storage strategy is CO₂ mineralization — specifically by dissolving gaseous CO₂ in water, which then reacts with reservoir rocks to form carbonate minerals. Of the technologies proposed for carbon sequestration, this approach is unique in that the sequestration is permanent: the CO₂ becomes part of an inert solid, so it cannot escape back into the environment. Basaltic rocks, the most common volcanic rock on Earth, present good sites for CO₂ injection due to their widespread occurrence and high concentrations of divalent cations such as calcium and magnesium that can form carbonate minerals. In one study, more than 95 percent of the CO₂ injected into a pilot site in Iceland was precipitated as carbonate minerals in less than two years.

However, ensuring the subsurface integrity of geological formations during fluid injection and accurately evaluating the reaction rates in such reservoirs require targeted studies such as Peč’s.

“The funding by MITEI’s Low-Carbon Energy Center for Carbon Capture, Utilization, and Storage allows me to start a new research direction, bringing together a group of experts from a range of disciplines to tackle climate change, perhaps the greatest scientific challenge our generation is facing,” says Peč.

The two projects were selected from a call for proposals that resulted in 15 entries by MIT researchers. “The application process revealed a great deal of interest from MIT researchers in advancing carbon capture, utilization, and storage processes and technologies,” says Bradford Hager, the Cecil and Ida Green Professor of Earth Sciences, who co-directs the CCUS center with T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering. “The two projects funded through the center will result in fundamental, higher-risk research exploring novel approaches that have the potential to have high impact in the longer term. Given the short-term focus of the industry, projects like this might not have otherwise been funded, so having support for this kind of early-stage fundamental research is crucial.”

Are we still listening to space?

Fernanda Ferreira | School of Science — Wed, 19 Aug 2020 14:45:01 -0400

When LIGO, the Laser Interferometer Gravitational-Wave Observatory, and its European counterpart, Virgo, detect a gravitational ripple from space, a public alert is sent out. That alert lets researchers know with a decently high confidence that this ripple was probably caused by an exceptional cosmic event, such as the collision of neutron stars or the merging of black holes, somewhere in the universe.

Then starts the scramble. A pair of researchers is assigned to the incoming event, analyzing the data to get a preliminary location in the sky whence the ripple emanated. Telescopes are pointed in that direction, more data is amassed, and the pair of researchers conducts further followup studies to try to determine what kind of event caused the wave.

“I often think of it as if we’re in a dark forest and listening to the ground,” says Eva Huang, a third-year Department of Physics graduate student in Assistant Professor Salvatore Vitale’s lab in the MIT Kavli Institute for Astrophysics and Space Research (MKI). “From the footsteps, we’re trying to guess what kind of animal is passing by.”

The LIGO-Virgo Collaboration keeps a rotation system to determine which researchers get to investigate the latest detection. Sylvia Biscoveanu, a second-year graduate student also in Vitale’s lab, was next on the list when LIGO suspended its third observational run due to Covid-19. If a cosmic event happens in the universe and there’s no one there to detect it, did it even happen?

Data analysis in isolation

When MIT similarly scaled back on-campus research in mid-March due to the coronavirus pandemic, the LIGO team at MKI adapted quickly to the new work-from-home normal. “Our work is physically less dependent on being at MIT,” says Vitale, who is also a member of the LIGO Scientific Collaboration. “Still, there are consequences.”

For Biscoveanu, working from home has entailed being at her computer for at least eight hours a day. “In terms of actually being able to do my research, I haven’t suffered,” she says. What has suffered is her ability to exchange ideas with other members of the LIGO group at MIT. “I had just moved to a bigger office with a bunch of graduate students, and we were really looking forward to being able to talk to each other and ask questions regularly,” says Biscoveanu. “I definitely don’t get as much of that at home.”

Mentorship also looks different when everyone is at home. Vitale has always had an open-door policy with his graduate students. “I do weekly meetings with my students, but on top of that I had close-to-daily interactions with them,” he says. Unless his door was closed, Vitale says, his students could come in and talk anytime. That immediate connection, he has found, is hard to replicate in the digital world.

“The thing I tell my students is that we don’t work in a hut where everyone is making their own project and then it’s done,” says Vitale. “Research is more than the sum of its parts.” One advantage of working in a group is the ability to turn to a colleague to discuss a paper you just read, a problem you’re facing, or a crazy idea you had the night before. That’s harder to do when everyone is stuck in their own hut.

“Now you have to go in the chat room or arrange a telecon if you want to ask a question,” says Ken Ng, a third-year graduate student in the Vitale group. Ng uses gravitational waves to study particle physics, with his work focusing on axions, a proposed elementary particle that is orders of magnitude smaller than the tiniest particle observed. Telecons and Slack, he has found, can be particularly inefficient when you’re trying to quickly sketch out an idea. “I’m actually thinking of buying a white board,” he says.

Space never stops

When the third observation run was suspended a month before it was supposed to end, it had collected 56 gravitational wave candidates. In comparison, the first two runs combined amassed a total of 11 candidates. So even though fresh data isn’t arriving in the lab, the work hasn’t ceased, and LIGO scientists are scrutinizing the data from home. “If the pandemic had happened a few months before, we could have missed half the data,” says Ng, looking on the positive side.

Compared to the other members of the lab, Ng is no pandemic rookie. When the Covid-19 pandemic struck, he thought, “Again?” Ng, who is from Hong Kong, faced the SARS outbreak in 2002 and considers himself the pandemic veteran of the group. That experience has kept him from panicking these days. “I know the importance of social distancing and mask-wearing,” he explains.

Still, for some in the group, social distancing has led to less productivity and feelings of guilt. “I sometimes feel that, because my work is less impacted, I cannot allow myself to feel frustrated,” says Huang. Her work — analyzing LIGO data to decipher the cosmic events responsible for detected waves — can be done at home, unlike researchers who need to be physically in-lab. Throughout the pandemic, Huang has worked hard to combat the feeling that she needs to earn permission to be self-compassionate. “I can be, and need to be, kind to myself during this time.

All are looking forward to the day when they can come back to campus. Partly, Ng confesses, for the free food. But mostly to continue studying gravitational waves in the same space. “I miss being able to chat randomly when people are in an office,” he says.

Vitale acknowledges that there have been some benefits of working from home. “This has obliged everyone to think a bit harder about how to express what we want to say,” he says. Still, like his students, he also can’t wait to leave his hut and get back to campus. “I think for all of us, it will also just be nice to be back at the office and re-establish a clear separation between our living and our working spaces, that right now are collapsed in the same entity.”

For student researchers, no pause for the pandemic

Leda Zimmerman | Department of Nuclear Science and Engineering — Tue, 18 Aug 2020 15:20:01 -0400

In mid-March, when the Covid-19 pandemic darkened MIT classrooms and labs, lights switched on for undergraduate research taking place remotely. Zooming in from time zones often distant from Cambridge, Massachusetts, many students were able to continue undergraduate research opportunities (UROPs) made possible by nuclear science and engineering faculty.

Advancing projects begun during January independent activities period or the start of spring semester, students overcame significant obstacles to make their research experiences meaningful while working from home — whether that home was in a manicured U.S. suburban subdivision, a palm-lined street in the Middle East, or, in the case of Quynh T. Nguyen, surrounded by local rice fields in Vietnam.

“It was tough returning to Dong Hoi City, because I thought that meant I was done with my UROP for the semester,” says the rising junior majoring in physics. Working with Assistant Professor Mingda Li, Nguyen had been investigating the thermal transport properties of materials, growing crystals in the lab. One goal of such work is optimizing heat transfer in materials to improve efficiency in energy production. “I was so grateful when Professor Li found ways for me to stay on the project from home,” he says.

While finishing his spring classes online — a major undertaking given the 11-hour time difference and difficulties accessing MIT servers — Nguyen pivoted with enthusiasm from lab work to developing machine learning applications for the same project.

“I’ve been excited about machine learning since taking a class, and so actually this UROP has allowed me to leverage my knowledge in an extremely new and interesting way for me,” says Nguyen.

Aljazzy Alahmadi, a rising sophomore, managed to get back to Saudi Arabia the day before such international flights were halted. “I was in a UROP meeting when MIT emailed the news, and I didn’t think about anything except getting home as fast as possible,” she recalls. But soon after she settled into life in Dammam, a city of more than a million on the Persian Gulf, she was relieved to learn that she could continue her project with graduate student Saleem Aldajani, within the lab of Associate Professor Michael P. Short.

“My work involves finding trends in the degradation of a stainless steel alloy often used in light water nuclear reactors when it’s under reactor-like thermal conditions,” she says. This kind of information might contribute to extended lifetimes for light water reactors. But after training with steel cutting and specialized spectroscopy techniques in the lab, her remote location necessitated a turn to data analysis instead.

“I was kind of happy about this switch,” Alahmadi says. “When I began the project, I didn’t really grasp what it was all about — I was learning how to cut steel samples — so when I started focusing on datasets I could intellectually explore in a way I couldn’t before.”

After she returned to her home in Katy, Texas, a small city in Houston’s shadow, Andrea Garcia, a rising sophomore, says she felt “kind of devastated.” Drawn to disciplines that would enable her to address environmental problems and climate change, Garcia had just decided to concentrate in materials science and engineering. “I had a lot of things planned for the rest of the semester,” she says, including a UROP in the Short lab. After hearing him lecture about the promise of fusion energy in the fall, Garcia had determined to learn more about nuclear energy more broadly.

She leapt into Short’s project, spending weeks learning how to use lasers safely. “Then we got kicked out due to Covid,” says Garcia. “I thought there’d be no way for undergraduate researchers to keep doing the research, but Professor Short made it happen, offering to run experiments and send us the data.”

Flying (mostly) solo

Although routinely in touch with faculty and lab supervisors via email and Zoom meetings, the students were on their own for the most part during spring semester and beyond. While they found the physical isolation from a team challenging at times, the undergraduates also relished their independence.

“I was analyzing data on irradiated samples of titanium aluminum metals, focused on thermal diffusivity, and was left to my own devices,” says Garcia. “Every week, we had to present our findings, and I came to feel a sense of ownership, that I was having an impact and that my work was achieving something.”

Investigating electrical and thermal conductivity of crystals that feature some unique quantum properties proved fascinating to Nguyen, not least because it catalyzed him to “learn many new things related to machine learning on Coursera,” as well as to investigate domains of physics previously unfamiliar to him. He especially enjoyed prowling through vast online databases: “I find it amazing that scientists have built these repositories and made them available for everyone to access.”

Alahmadi felt energized by the quest to find something of value in her datasets. “With this project, I felt I couldn’t leave until I reached a point of a deliverable,” she says. “I wanted to get a result, publish a paper, go to a conference — get the full experience of this.”

Sticking with it

Although their fall plans might be uncertain, these students remain anchored by their continuing research. Garcia, who found that she enjoyed using Python to create graphs mapping the properties of her material samples, says the experience reminded her “that computer science is a useful skill.” As a result, she hopes to bear down on her materials science major while taking more computer science courses.

“My wildest dream, which keeps me going, is to incorporate power systems in Saudi that don’t use carbon,” Alahmadi says. She hopes to stick with her UROP, wherever she is living. “It’s taught me to open my eyes to all things so I can learn new skills, from acquiring new capabilities to make projects go faster, to collaborating well with other lab members.”

Nguyen, who is targeting a career in applied physics, feels his experience with the UROP “is invaluable for my future,” he says. He has co-authored a scientific publication, and feels deep ties to his Cambridge-based research group. He has come to view this difficult period not as an obstacle, but an opportunity. “It’s an unprecedented experience, working and communicating remotely,” he says. “We are all experiencing a painful pandemic, but as Professor Li notes we are living in a historic time that will one day be memorialized in movies and books, so it’s not all bad.”

Nergis Mavalvala named School of Science dean

Jennifer Chu | MIT News Office — Mon, 17 Aug 2020 09:11:56 -0400

Astrophysicist Nergis Mavalvala has been named the new dean of MIT’s School of Science, effective Sept. 1. She will succeed Michael Sipser, who will return to the faculty as the Donner Professor of Mathematics, after six years of service.

Mavalvala, the Curtis and Kathleen Marble Professor of Astrophysics, is renowned for her pioneering work in gravitational-wave detection, which she conducted as a leading member of LIGO, the Laser Interferometer Gravitational-Wave Observatory. She has received numerous awards and honors for her research and teaching, and since 2015 has been the associate head of the Department of Physics. Mavalvala will be the first woman to serve as dean in the School of Science.

“Nergis’s brilliance as a researcher and educator speaks eloquently for itself,” says MIT President L. Rafael Reif. “What excites me equally about her appointment as dean are the qualities I have seen in her as a leader: She is a deft, collaborative problem-solver, a wise and generous colleague, an incomparable mentor, and a champion for inclusive excellence. As we prepare for the start of this most unusual academic year, it gives me great comfort to know that the School of Science will remain in such capable hands.”

Provost Martin Schmidt announced the news today in a letter emailed to the MIT community, writing, “I very much look forward to working with Nergis and to benefiting from her unerring sense of scientific opportunity, infectious curiosity, down-to-earth manner and practical wisdom. I hope you will join me in congratulating her as she brings her great gifts as a leader to this new role.”

As with most everything she takes on, Mavalvala is energized and optimistic about the role ahead, even as she acknowledges the unprecedented challenges that the school, and the Institute as a whole, are facing in these shifting times.

“We’re in this moment where enormous changes are afoot,” Mavalvala says. “We’re in the middle of a global pandemic and economic challenge, and we’re also in a moment, at least in U.S. history, where the imperative for racial and social justice is really strong. As someone in a leadership position, that means you have opportunities to make an important and hopefully lasting impact.”

Leading with heart and mind

For the past five years as associate head of physics, Mavalvala oversaw the department’s academic programming and student well-being. She implemented new, more flexible doctoral requirements and exams, and expanded the department’s digital learning portfolio with the development of online versions for a number of core subjects. She also introduced changes to the department’s undergraduate and graduate advising, and helped to set in motion an extensive mentoring program.

In collaboration with department head Peter Fisher, she co-founded the Physics Values Committee, a group of faculty, staff, and students who advise the department on issues of well-being, respect, inclusion, collaboration, and mentorship. The committee developed the department’s first values statement, which has become a model for departments and units across MIT, and at other universities.

Mavalvala launched initiatives to meet the department’s goals of education and advising, while aiming to reduce stress and workload on students, faculty, and staff. She also helped to revise the department’s graduate admissions procedures in order to increase equity and promote a more diverse student body.

Mavalvala has also made it a priority to listen to students, through town hall meetings, open office hours, and by including student representatives in key departmental committees.

“I have had the privilege of working with some amazing people,” she says of her time as associate department head. She credits the many students and colleagues she has worked closely with, especially Fisher: “Through him, I’ve learned about leadership with compassion, with heart.”

“Learning the language”

Mavalvala was born in Lahore, Pakistan, and grew up in Karachi. A tinkerer by nature, she often got up to her elbows in grease as she absorbed herself in the mechanics of bike repair. In school, she gravitated to math and physics early on, and her parents, strong advocates of both their daughters’ education, encouraged her to apply to college overseas.

At Wellesley College, she earned a bachelor’s degree in physics and astronomy, before moving to MIT in 1990, where she pursued a PhD in physics. Her advisor, Rainier Weiss, now professor emeritus of physics, was working out how to physically realize his idea of an interferometer to detect gravitational waves — minute disturbances rippling out through space from cataclysmic events millions to billions of light years away.

Mavalvala dove into the fledgling project, helping Weiss to build an early prototype of a gravitational-wave detector as part of her PhD thesis. Weiss’ idea would eventually take shape as LIGO, the twin 4-kilometer-long interferometers that in 2016 made the first direct detection of gravitational waves, a historic discovery that won Weiss and others the 2017 Nobel Prize in physics.

After completing her PhD work at MIT, Mavalvala went to Caltech in 1997 as a postdoc, studying the cosmic microwave background. In 2000, she joined on as a staff scientist at the LIGO Laboratory, where researchers were collaborating with Weiss’ group at MIT to build LIGO’s detectors. She spent two years with the Caltech team before accepting a position that took her back to MIT, where she joined the faculty in 2002 as assistant professor of physics.

Since then, she has helped to build up the MIT LIGO group, where she has worked to design and improve different parts of the interferometers. She also has led a team of scientists in developing tools to study and manipulate the barely perceptible quantum effects on LIGO’s massive detectors.

“To make an experiment like LIGO work, as large and complex that it is, takes the collaboration of hundreds of scientists, across geographical and cultural distances,” says Mavalvala, who sees useful crossover with her new role at the School of Science helm. “It’s good training for the dean’s position, because that’s going to require also spanning not just different fields of physics, but different fields of science, and learning the language of those fields.”

Mavalvala is a recipient of numerous honors and awards, including in 2010 the MacArthur Fellowship. In 2014, the National Organization of Gay and Lesbian Scientists and Technical Professionals recognized her as the LGBTQ+ Scientist of the year, and in 2015 she was awarded the Special Breakthrough Prize in Fundamental Physics, as part of the LIGO team. In 2017, she was elected to the National Academy of Sciences. That same year, the Carnegie Corporation of New York recognized Mavalvala as a Great Immigrant honoree. She is also the first recipient of the Lahore Technology Award, given by the Information Technology University, a public university in Pakistan.

“A better MIT”

Mavalvala is optimistic about the road ahead and credits her predecessors, and especially Michael Sipser, for paving the way.

“In some ways, the years leading up to the pandemic have been good years for MIT from the side of scientific discovery, and our impact on the world,” Mavalvala says. “I’m awed by the number of things that Mike has done and has left in good shape. I will always be grateful for that, and plan to carry on with the many things that work well, while also continually improving what we do and how we do it, as needs and demands shift.”

Since LIGO’s first detection of gravitational waves was reported in 2016, Mavalvala, with her deep passion for science and lively personality, has been sought after as a sort of unofficial ambassador to the public on behalf of astrophysics and STEM more broadly. Her identity as an openly queer immigrant woman scientist of color has also brought her public attention. As she takes on her new role, Mavalvala plans to continue to engage a wide audience with her passion for science and discovery.

“MIT is one of the top places in the world for doing cutting-edge science, and we will continue to maintain that eminence. At the same time, we also have to push on issues of diversity, issues of racial and social justice, and of work-life balance,” says Mavalvala, who is also a parent of two children. “There’s this idea at places like MIT that to be as excellent as we are in science and education, that has to come at the cost of all other aspects of being human. I reject that idea. So part of what I’d like to do, and part of my vision of a better MIT, is to find ways for those things to coexist, in good balance. I don’t have any illusions that some of these things will be harder to do, but it doesn’t mean we shouldn’t try.”

Meet Lauryn Kortman: Juggling fusion magnets and LED batons

Paul Rivenberg | Plasma Science and Fusion Center — Wed, 12 Aug 2020 16:20:01 -0400

When Lauryn Kortman enrolled in Founder’s Journey, MIT’s entrepreneur-based first-year student seminar, she didn’t expect it would lead to a role in fusion research. As part of the program’s arranged visit to the Plasma Science and Fusion Center (PSFC), Kortman learned about SPARC, a new fusion experiment that expects to demonstrate a faster and less-expensive path to carbon-free energy. The project embodied her own entrepreneurial spirit and sparked in her a desire to be part of the team.

“I emailed a bunch of PSFC researchers because I didn’t see any Undergraduate Research Opportunity Program (UROP) listing,” she says. “I wanted to see if I could get involved in the material side of the experiment.”

The materials science and engineering major’s request got the attention of PSFC Director Dennis Whyte and postdoc David Fischer, now her direct supervisor, who introduced her to ARC, a follow-up to SPARC. Both machines are conventional tokamaks, with magnets surrounding a toroidal vacuum chamber to confine the hot plasma fuel long enough for self-sustaining fusion to occur. Both will take advantage of a technologically advanced high-temperature superconducting (HTS) tape made of rare-earth barium copper oxide, which will make it possible to design a more compact device. The magnets in SPARC, however, will endure pulses of plasma for only a few seconds, accumulating little damage over time. ARC is expected to run for longer periods, amassing damage that could alter the magnets’ superconducting properties.

Working with the DANTE electrostatic accelerator in MIT’s Vault Laboratory for Nuclear Science, Kortman was tasked with setting up the experiment and putting together all the components of the vacuum chamber, where the HTS tape would be tested. Fixed to a sample holder, the tape is bombarded with protons, which mars the microstructure. To study the effect of the resulting damage it is necessary to cool the sample to cryogenic temperatures and run a current over it, while measuring the voltage across it and looking for the point where the material becomes resistive. The onset of this resistance changes with the amount of radiation damage. Once the team understands how much radiation damage the tape can sustain, the necessary shielding can be determined to achieve the desired lifetime of the fusion magnets.

Kortman enjoyed the process of creating 3D drawings of the experimental setup, allowing the researchers to understand how much space they had to add more elements to the vacuum chamber. But when, in response to Covid-19, she returned home to Alabama, she found herself sharpening other necessary skills.

She is now coding the graphical user interfaces that will be used to control part of the experiment and to acquire data. The task has required her to learn Python and develop skills she was not expecting to hone at this time.

“I do recognize it’s something I need to know,” she admits. “One of my big issues with coding in classes is we are doing it for something like a Hangman game. I kind of lose interest because I don’t see it being applied anywhere that would be useful. But I'm glad I’m able to do it for a project where I can see it actually being used.”

Kortman has always been more of a designer than a coder. As a majorette in high school, frustrated that she was not allowed to twirl a fire baton and unimpressed with the expensive “light-up” options available online, she designed her own illuminated version.

“I thought, ‘OK, I have enough engineering experience at this point in my junior year; why don’t I try to just make one myself?’ So, I started prototyping. My dad also helped me along the way, teaching me how to solder and make circuits. I pitched it to my band director to use it in a show and got the OK. So, I got to twirl my own LED baton my senior year, along with my majorette line.”

The performance led to requests from majorettes, coaches, and parents, wondering where they could buy such a baton. Inspired by the enthusiasm, she decided to try to sell the unique item. She now heads her own company, FireFly Batons.

Although her return to Alabama has taken her out of the lab, it has put her back into baton production, which has been good for business. The baton, which features a custom-engineered LED-filled shaft, requires space and time to assemble. Although her father was willing to handle the bulk of the orders when his daughter left for MIT, the business was having a hard time finding its rhythm and really getting off the ground.

“We were about to close down the company,” she says, “but when coronavirus hit and I was sent home like everyone else it actually made an opportunity for me to be here and help out.”

Her focus on advertising and putting videos on social media has led to an uptick in sales since her return. She is happy to be dividing her summer between her business and her UROP assignment.

David Fischer has been impressed with her versatility. “She picks up new concepts fast,” he says. “She already has made good contributions and is now working mainly with our graduate student. I give them programming tasks, and every week they show me the results and I think I have to step up the difficulty because they always can manage.”

Kortman is making the most of her time away and imagining what her next semester on campus will be like, whenever that might be. Perhaps she will join MIT’s Spinning Arts Club, which offers the opportunity to spin and throw batons lit with fire into the air.

But for now she is throwing light on a fusion future.

Study suggests animals think probabilistically to distinguish contexts

David Orenstein | Picower Institute for Learning and Memory — Wed, 12 Aug 2020 14:00:01 -0400

Among the many things rodents have taught neuroscientists is that, in a region called the hippocampus, the brain creates a new map for every unique spatial context — for instance, a different room or maze. But scientists have so far struggled to learn how animals decide when a context is novel enough to merit creating, or at least revising, these mental maps. In a study in eLife, MIT and Harvard University researchers propose a new understanding: The process of “remapping” can be mathematically modeled as a feat of probabilistic reasoning by the rodents.

The approach offers scientists a new way to interpret many experiments that depend on measuring remapping to investigate learning and memory. Remapping is integral to that pursuit, because animals (and people) associate learning closely with context, and hippocampal maps indicate which context an animal believes itself to be in.

“People have previously asked ‘What changes in the environment cause the hippocampus to create a new map?’ but there haven’t been any clear answers,” says lead author Honi Sanders. “It depends on all sorts of factors, which means that how the animals define context has been shrouded in mystery.”

Sanders is a postdoc in the lab of co-author Matthew Wilson, Sherman Fairchild Professor in The Picower Institute for Learning and Memory and the departments of Biology and Brain and Cognitive Sciences at MIT. He is also a member of the Center for Brains, Minds and Machines. The pair collaborated with Samuel Gershman, a professor of psychology at Harvard.

A fundamental problem with remapping that has frequently led labs to report conflicting, confusing, or surprising results, is that scientists cannot simply assure their rats that they have moved from experimental Context A to Context B, or that they are still in Context A, even if some ambient condition, like temperature or odor, has inadvertently changed. It is up to the rat to explore and infer that conditions like the maze shape, or smell, or lighting, or the position of obstacles and rewards, or the task they must perform, have or have not changed enough to trigger a full or partial remapping.

So, rather than trying to understand remapping measurements based on what the experimental design is supposed to induce, Sanders, Wilson, and Gershman argue that scientists should predict remapping by mathematically accounting for the rat’s reasoning using Bayesian statistics, which quantify the process of starting with an uncertain assumption and then updating it as new information emerges.

“You never experience exactly the same situation twice. The second time is always slightly different,” Sanders says. “You need to answer the question: ‘Is this difference just the result of normal variation in this context or is this difference actually a different context?’ The first time you experience the difference you can’t be sure, but after you’ve experienced the context many times and get a sense of what variation is normal and what variation is not, you can pick up immediately when something is out of line.”

The trio call their approach “hidden state inference” because to the animal, the possible change of context is a hidden state that must be inferred.

In the study, the authors describe several cases in which hidden state inference can help explain the remapping, or the lack of it, observed in prior studies.

For instance, in many studies it’s been difficult to predict how changing some of the cues that a rodent navigates by in a maze (e.g., a light or a buzzer) will influence whether it makes a completely new map or partially remaps the current one, and by how much. Mostly the data has showed there isn’t an obvious “one-to-one” relationship of cue change and remapping. But the new model predicts how, as more cues change, a rodent can transition from becoming uncertain about whether an environment is novel (and therefore partially remapping) to becoming sure enough of that to fully remap.

In another, the model offers a new prediction to resolve a remapping ambiguity that has arisen when scientists have incrementally “morphed” the shape of rodent enclosures. Multiple labs, for instance, found different results when they familiarized rats with square and round environments and then tried to measure how and whether they remap when placed in intermediate shapes, such as an octagon. Some labs saw complete remapping, while others observed only partial remapping. The new model predicts how that could be true: rats exposed to the intermediate environment after longer training would be more likely to fully remap than those exposed to the intermediate shape earlier in training, because with more experience they would be more sure of their original environments, and therefore more certain that the intermediate one was a real change.

The math of the model even includes a variable that can account for differences between individual animals. Sanders is looking at whether rethinking old results in this way could allow researchers to understand why different rodents respond so variably to similar experiments.

Ultimately, Sanders says, he hopes the study will help fellow remapping researchers adopt a new way of thinking about surprising results — by considering the challenge their experiments pose to their subjects.

“Animals are not given direct access to context identities, but have to infer them,” he says. “Probabilistic approaches capture the way that uncertainty plays a role when inference occurs. If we correctly characterize the problem the animal is facing, we can make sense of differing results in different situations because the differences should stem from a common cause: the way that hidden state inference works.”

The U.S. National Science Foundation funded the research.

SMART research enhances dengue vaccination in mice

Singapore-MIT Alliance for Research and Technology — Tue, 11 Aug 2020 14:00:01 -0400

Researchers from the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, have found a practical way to induce a strong and broad immunity to the dengue virus based on proof-of-concept studies in mice. Dengue is a mosquito-borne viral disease with an estimated 100 million symptomatic infections every year. It is endemic in over 100 countries in the world, from the United States to Africa and wide swathes of Asia. In Singapore, over 1,700 dengue new cases were reported recently.

The study is reported in a paper titled “Sequential immunization induces strong and broad immunity against all four dengue virus serotypes,” published in NPJ Vaccines. It is jointly published by SMART researchers Jue Hou, Shubham Shrivastava, Hooi Linn Loo, Lan Hiong Wong, Eng Eong Ooi, and Jianzhu Chen from SMART’s Infectious Diseases and Antimicrobial Resistance (AMR) interdisciplinary research groups (IRGs).

The dengue virus (DENV) consists of four antigenically distinct serotypes and there is no lasting immunity following infection with any of the DENV serotypes, meaning someone can be infected again by any of the remaining three variants of DENVs.

Today, Dengvaxia is the only vaccine available to combat dengue. It consists of four variant dengue antigens, one for each of the four serotypes of dengue, expressed from attenuated yellow-fever virus. The current three doses of immunization with the tetravalent vaccine induce only suboptimal protection against DENV1 and DENV2. Furthermore, in people who have not been infected by dengue, the vaccine induces a more severe dengue infection in the future. Therefore, in most of the world, the vaccination is only given to those who have been previously infected.

To help overcome these issues, SMART researchers tested on mice whether sequential immunization (or one serotype per dose) induces stronger and broader immunity against four DENV serotypes than tetravalent-formulated immunization — and found that sequential immunization induced significantly higher levels of virus-specific T cell responses than tetravalent immunization. Moreover, sequential immunization induced higher levels of neutralizing antibodies to all four DENV serotypes than tetravalent vaccination.

“The principle of sequential immunization generally aligns with the reality for individuals living in dengue-endemic areas, whose immune responses may become protective after multiple heterotypic exposures,” says Professor Eng Eong Ooi, SMART AMR principal investigator and senior author of the study. “We were able to find a similar effect based on the use of sequential immunization, which will pave the way for a safe and effective use of the vaccine and to combat the virus.”

Upon these promising results, the investigators will aim to test the sequential immunization in humans in the near future.

The work was supported by the National Research Foundation (NRF) Singapore through the SMART Infectious Disease Research Program and AMR IRG. SMART was established by MIT in partnership with the NRF Singapore in 2007. SMART is the first entity in the Campus for Research Excellence and Technological Enterprise (CREATE) developed by NRF. SMART serves as an intellectual and innovation hub for research interactions between MIT and Singapore, performing cutting-edge research of interest to both Singapore and MIT. SMART currently comprises an Innovation Centre and five IRGs: AMR, Critical Analytics for Manufacturing Personalized-Medicine, Disruptive and Sustainable Technologies for Agricultural Precision, Future Urban Mobility, and Low Energy Electronic Systems. SMART research is funded by the NRF Singapore under the CREATE program.

The AMR IRG is a translational research and entrepreneurship program that tackles the growing threat of antimicrobial resistance. By leveraging talent and convergent technologies across Singapore and MIT, they aim to tackle AMR head-on by developing multiple innovative and disruptive approaches to identify, respond to, and treat drug-resistant microbial infections. Through strong scientific and clinical collaborations, they provide transformative, holistic solutions for Singapore and the world.

Nuh Gedik and Pablo Jarillo-Herrero are 2020 Moore Experimental Investigators in Quantum Materials

Sandi Miller | Department of Physics — Mon, 10 Aug 2020 15:25:36 -0400

Physics professors Nuh Gedik and Pablo Jarillo-Herrero have been named Experimental Investigators in Quantum Materials by the Gordon and Betty Moore Foundation.

The two are among 20 winners nationwide of the foundation's Emergent Phenomena in Quantum Systems (EPiQS) Initiative. Each will receive a five-year, $1.6 million unrestricted grant to support their research in quantum materials.

Gedik’s research centers on using advanced optical techniques for probing and controlling properties of quantum materials. He will use his grant to search for novel, light-induced phases in these systems.

“These materials display fascinating but poorly understood properties, such as high-temperature superconductivity or topological protection,” says Gedik. “We use ultrafast laser pulses to make femtosecond movies of electrons and atoms inside these systems to understand the mechanism behind their exotic behavior. Our ultimate goal is to use light as a controllable tuning parameter (just as magnetic field or pressure) to switch between equilibrium phases and to engineer new light-induced states with no equilibrium counterparts.”

Jarillo-Herrero, the Cecil and Ida Green Professor of Physics, leads a laboratory that uses quantum electronic transport and optoelectronic techniques to investigate novel 2D materials and heterostructures, with a focus on emergent correlated and topological phenomena/phases resulting from the interplay between unusual electronic structures and electron interaction effects.

“This Moore Foundation award will allow my group to focus on a novel experimental platform called twistronics, where a new degree of freedom, namely the twist angle between two stacked 2D crystalline lattices, enables the exploration of a plethora of intriguing quantum mechanical effects, such as superconductivity. This emergent platform may provide important clues about the origin of many of the most fascinating phases of matter present in the universe, as well as the potential engineering of these phases to create new quantum technologies.”

The EPiQS Initiative of the Gordon and Betty Moore Foundation aims to stimulate experimental research in the physics of quantum materials by providing some of the field’s most creative scientists with freedom to take risks and flexibility for agile change of research direction. The collective impact of these investigators will produce a more comprehensive understanding of the fundamental organizing principles of complex quantum matter in solids.

“The Experimental Investigator awards are the largest grant portfolio within the EPiQS initiative,” says Amalia Fernandez-Pañella, program officer of the EPiQS Initiative. “We expect that such substantial, stable, and flexible support will propel quantum materials research forward and unleash the creativity of the investigators.”

The cohort’s research will cover a broad spectrum of research questions, types of materials systems, and complementary experimental approaches. The investigators will advance experimental probes of quantum states in materials; elucidate emergent phenomena observed in systems with strong electron interactions; investigate light-induced states of matter; explore the vast space of two-dimensional layered structures; and illuminate the role of quantum entanglement in exotic systems such as quantum spin liquids. In addition, the investigators will participate in EPiQS community-building activities, which include investigator symposia, topical workshops, and the QuantEmX scientist exchange program.

Since 2013, EPiQS has supported an integrated research program that includes materials synthesis, experiment, and theory, and that crosses the boundaries between physics, chemistry, and materials science. The second phase of the initiative was kicked off earlier this year with the launch of two major grant portfolios: Materials Synthesis Investigators and Theory Centers. The 20 newly inaugurated experimental investigators will join these grantees to form a vibrant, collaborative community that strives to push the entire field toward a new frontier.

“The first cohort of EPiQS Experimental Investigators made advances that changed the landscape of quantum materials, and I expect no less from this second cohort. Emergent phenomena appear when a large number of constituents interact strongly, whether these constituents are electrons in materials, or the brilliant scientists trying to crack the mysteries of materials.” says Dušan Pejaković, director of the EPiQS Initiative. Gedik and Jarillo-Herrero were also part of the first cohort of EPIQS awardees.

The Gordon and Betty Moore Foundation fosters pathbreaking scientific discovery, environmental conservation, patient care improvements, and preservation of the special character of the San Francisco Bay Area.

Key brain region was “recycled” as humans developed the ability to read

Anne Trafton | MIT News Office — Tue, 04 Aug 2020 10:51:18 -0400

Humans began to develop systems of reading and writing only within the past few thousand years. Our reading abilities set us apart from other animal species, but a few thousand years is much too short a timeframe for our brains to have evolved new areas specifically devoted to reading.

To account for the development of this skill, some scientists have hypothesized that parts of the brain that originally evolved for other purposes have been “recycled” for reading. As one example, they suggest that a part of the visual system that is specialized to perform object recognition has been repurposed for a key component of reading called orthographic processing — the ability to recognize written letters and words.

A new study from MIT neuroscientists offers evidence for this hypothesis. The findings suggest that even in nonhuman primates, who do not know how to read, a part of the brain called the inferotemporal (IT) cortex is capable of performing tasks such as distinguishing words from nonsense words, or picking out specific letters from a word.

“This work has opened up a potential linkage between our rapidly developing understanding of the neural mechanisms of visual processing and an important primate behavior — human reading,” says James DiCarlo, the head of MIT’s Department of Brain and Cognitive Sciences, an investigator in the McGovern Institute for Brain Research and the Center for Brains, Minds, and Machines, and the senior author of the study.

Rishi Rajalingham, an MIT postdoc, is the lead author of the study, which appears today in Nature Communications. Other MIT authors are postdoc Kohitij Kar and technical associate Sachi Sanghavi. The research team also includes Stanislas Dehaene, a professor of experimental cognitive psychology at the Collège de France.

Word recognition

Reading is a complex process that requires recognizing words, assigning meaning to those words, and associating words with their corresponding sound. These functions are believed to be spread out over different parts of the human brain.

Functional magnetic resonance imaging (fMRI) studies have identified a region called the visual word form area (VWFA) that lights up when the brain processes a written word. This region is involved in the orthographic stage: It discriminates words from jumbled strings of letters or words from unknown alphabets. The VWFA is located in the IT cortex, a part of the visual cortex that is also responsible for identifying objects.

DiCarlo and Dehaene became interested in studying the neural mechanisms behind word recognition after cognitive psychologists in France reported that baboons could learn to discriminate words from nonwords, in a study that appeared in Science in 2012.

Using fMRI, Dehaene’s lab has previously found that parts of the IT cortex that respond to objects and faces become highly specialized for recognizing written words once people learn to read.

“However, given the limitations of human imaging methods, it has been challenging to characterize these representations at the resolution of individual neurons, and to quantitatively test if and how these representations might be reused to support orthographic processing,” Dehaene says. “These findings inspired us to ask if nonhuman primates could provide a unique opportunity to investigate the neuronal mechanisms underlying orthographic processing.”

The researchers hypothesized that if parts of the primate brain are predisposed to process text, they might be able to find patterns reflecting that in the neural activity of nonhuman primates as they simply look at words.

To test that idea, the researchers recorded neural activity from about 500 neural sites across the IT cortex of macaques as they looked at about 2,000 strings of letters, some of which were English words and some of which were nonsensical strings of letters.

“The efficiency of this methodology is that you don't need to train animals to do anything,” Rajalingham says. “What you do is just record these patterns of neural activity as you flash an image in front of the animal.”

The researchers then fed that neural data into a simple computer model called a linear classifier. This model learns to combine the inputs from each of the 500 neural sites to predict whether the string of letters that provoked that activity pattern was a word or not. While the animal itself is not performing this task, the model acts as a “stand-in” that uses the neural data to generate a behavior, Rajalingham says.

Using that neural data, the model was able to generate accurate predictions for many orthographic tasks, including distinguishing words from nonwords and determining if a particular letter is present in a string of words. The model was about 70 percent accurate at distinguishing words from nonwords, which is very similar to the rate reported in the 2012 Science study with baboons. Furthermore, the patterns of errors made by model were similar to those made by the animals.

Neuronal recycling

The researchers also recorded neural activity from a different brain area that also feeds into IT cortex: V4, which is part of the visual cortex. When they fed V4 activity patterns into the linear classifier model, the model poorly predicted (compared to IT) the human or baboon performance on the orthographic processing tasks.

The findings suggest that the IT cortex is particularly well-suited to be repurposed for skills that are needed for reading, and they support the hypothesis that some of the mechanisms of reading are built upon highly evolved mechanisms for object recognition, the researchers say.

The researchers now plan to train animals to perform orthographic tasks and measure how their neural activity changes as they learn the tasks.

The research was funded by the Simons Foundation and the U.S. Office of Naval Research.

Lava oceans may not explain the brightness of some hot super-Earths

Jennifer Chu | MIT News Office — Tue, 04 Aug 2020 00:00:00 -0400

Arguably some of the weirdest, most extreme planets among the more than 4,000 exoplanets discovered to date are the hot super-Earths — rocky, flaming-hot worlds that zing so precariously close to their host stars that some of their surfaces are likely melted seas of molten lava.

These fiery worlds, about the size of Earth, are known more evocatively as “lava-ocean planets,” and scientists have observed that a handful of these hot super-Earths are unusually bright, and in fact brighter than our own brilliant blue planet.

Exactly why these far-off fireballs are so bright is unclear, but new experimental evidence by scientists at MIT shows that the unexpected glow from these worlds is likely not due to either molten lava or cooled glass (i.e. rapidly solidified lava) on their surfaces.

The researchers came to this conclusion after interrogating the problem in a refreshingly direct way: melting rocks in a furnace and measuring the brightness of the resulting lava and cooled glass, which they then used to calculate the brightness of regions of a planet covered in molten or solidified material. Their results revealed that lava and glass, at least as a product of the materials they melted in the lab, are not reflective enough to explain the observed brightness of certain lava-ocean planets.

Their findings suggest that hot super-Earths may have other surprising features that contribute to their brightness, such as metal-rich atmospheres and highly reflective clouds.

“We still have so much to understand about these lava-ocean planets,” says Zahra Essack, a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “We thought of them as just glowing balls of rock, but these planets may have complex systems of surface and atmospheric processes that are quite exotic, and not anything we’ve ever seen before.”

Essack is the first author of a study detailing the team’s results, which appears today in The Astrophysical Journal. Her co-authors are former MIT postdoc Mihkel Pajusalu, who was instrumental in the experiment’s initial setup, and Sara Seager, the Class of 1941 Professor of Planetary Science, with appointments in the departments of Physics and Aeronautics and Astronautics.

More than charcoal balls

Hot super-Earths are between one and 10 times the mass of Earth, and have extremely short orbital periods, circling their host star in just 10 days or less. Scientists have expected that these lava worlds would be so close to their host star that any appreciable atmosphere and clouds would be stripped away. Their surfaces as a result would be at least 850 kelvins, or 1,070 degrees Fahrenheit — hot enough to cover the surface in oceans of molten rock.

Scientists have previously discovered a handful of super-Earths with unexpectedly high albedos, or brightnesses, in which they reflected between 40 and 50 percent of the light from their star. In comparison, the Earth’s albedo, with all of its reflective surfaces and clouds, is only around 30 percent.

“You’d expect these lava planets to be sort of charcoal balls orbiting in space — very dark, not very bright at all,” Essack says. “So what makes them so bright?”

One idea has been that the lava itself may be the main source of the planets’ luminosity, though there had never been any proof, either in observations or experiments.

“So being MIT people, we decided, ok, we should make some lava and see if it’s bright or not,” Essack says.

Making lava

To first make lava, the team needed a furnace that could reach temperatures high enough to melt basalt and feldspar, the two rock types that they chose for their experiments, as they are well-characterized material that are common on Earth.

As it turns out, they initially didn’t have to look farther than the foundry at MIT, a space within the Department of Materials Science and Engineering, where trained metallurgists help students and researchers melt materials in the foundry’s furnace for research and class projects.

Essack brought samples of feldspar to the foundry, where metallurgists determined the type of crucible in which to place them, and the temperatures at which they needed to be heated.

“They drop it in the furnace, let the rocks melt, take it out, and then the whole place turns into a furnace itself — it’s very hot,” Essack says. “And it was an incredible experience to stand next to this bright glowing lava, feeling that heat.”

However, the experiment quickly ran up against an obstacle: The lava, once it was pulled from the furnace, almost instantly cooled into a smooth, glassy material. The process occurred so quickly that Essack wasn’t able to measure the lava’s reflectivity while still molten.

So she took the cooled feldspar glass to a spectroscopy lab she designed and implemented on campus to measure its reflectance, by shining a light on the glass from different angles and measuring the amount of light reflecting back from the surface. She repeated these experiments for cooled basalt glass, samples of which were donated by colleagues at Syracuse University who run the Lava Project. Seager visited them a few years ago for a preliminary version of the experiment, and at that time collected basalt samples now used for Essack’s experiments.

“They melted a huge bunch of basalt and poured it down a slope, and they chipped it up for us,” Seager says.

After measuring the brightness of cooled basalt and feldspar glass, Essack looked through the literature to find reflectivity measurements of molten silicates, which are a major component of lava on Earth. She used these measurements as a reference to calculate how bright the initial lava from the basalt and feldspar glass would be. She then estimated the brightness of a hot super-Earth covered either entirely in lava or cooled glass, or combinations of the two materials.

In the end, she found that, no matter the combination of surface materials, the albedo of a lava-ocean planet would be no more than about 10 percent — pretty dark compared with the 40 to 50 percent albedo observed for some hot super-Earths.

“This is quite dark compared to Earth, and not enough to explain the brightness of the planets we were interested in,” Essack says.

This realization has narrowed the search range for interpreting observations, and directs future studies to consider other exotic possibilities, such as the presence of atmospheres rich in reflective metals.

“We’re not 100 percent sure what these planets are made of, so we’re narrowing the parameter space and guiding future studies toward all these other potential options,” Essack says.

This research was funded, in part, by NASA’s TESS mission and, in part, by the MIT Presidential Fellowship.