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      in Energy

      Seeing the plasma edge of fusion experiments in new ways with artificial intelligence

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      To make fusion energy a viable resource for the world’s energy grid, researchers need to understand the turbulent motion of plasmas: a mix of ions and electrons swirling around in reactor vessels. The plasma particles, following magnetic field lines in toroidal chambers known as tokamaks, must be confined long enough for fusion devices to produce significant gains in net energy, a challenge when the hot edge of the plasma (over 1 million degrees Celsius) is just centimeters away from the much cooler solid walls of the vessel.

      Abhilash Mathews, a PhD candidate in the Department of Nuclear Science and Engineering working at MIT’s Plasma Science and Fusion Center (PSFC), believes this plasma edge to be a particularly rich source of unanswered questions. A turbulent boundary, it is central to understanding plasma confinement, fueling, and the potentially damaging heat fluxes that can strike material surfaces — factors that impact fusion reactor designs.

      To better understand edge conditions, scientists focus on modeling turbulence at this boundary using numerical simulations that will help predict the plasma’s behavior. However, “first principles” simulations of this region are among the most challenging and time-consuming computations in fusion research. Progress could be accelerated if researchers could develop “reduced” computer models that run much faster, but with quantified levels of accuracy.

      For decades, tokamak physicists have regularly used a reduced “two-fluid theory” rather than higher-fidelity models to simulate boundary plasmas in experiment, despite uncertainty about accuracy. In a pair of recent publications, Mathews begins directly testing the accuracy of this reduced plasma turbulence model in a new way: he combines physics with machine learning.

      “A successful theory is supposed to predict what you’re going to observe,” explains Mathews, “for example, the temperature, the density, the electric potential, the flows. And it’s the relationships between these variables that fundamentally define a turbulence theory. What our work essentially examines is the dynamic relationship between two of these variables: the turbulent electric field and the electron pressure.”

      In the first paper, published in Physical Review E, Mathews employs a novel deep-learning technique that uses artificial neural networks to build representations of the equations governing the reduced fluid theory. With this framework, he demonstrates a way to compute the turbulent electric field from an electron pressure fluctuation in the plasma consistent with the reduced fluid theory. Models commonly used to relate the electric field to pressure break down when applied to turbulent plasmas, but this one is robust even to noisy pressure measurements.

      In the second paper, published in Physics of Plasmas, Mathews further investigates this connection, contrasting it against higher-fidelity turbulence simulations. This first-of-its-kind comparison of turbulence across models has previously been difficult — if not impossible — to evaluate precisely. Mathews finds that in plasmas relevant to existing fusion devices, the reduced fluid model’s predicted turbulent fields are consistent with high-fidelity calculations. In this sense, the reduced turbulence theory works. But to fully validate it, “one should check every connection between every variable,” says Mathews.

      Mathews’ advisor, Principal Research Scientist Jerry Hughes, notes that plasma turbulence is notoriously difficult to simulate, more so than the familiar turbulence seen in air and water. “This work shows that, under the right set of conditions, physics-informed machine-learning techniques can paint a very full picture of the rapidly fluctuating edge plasma, beginning from a limited set of observations. I’m excited to see how we can apply this to new experiments, in which we essentially never observe every quantity we want.”

      These physics-informed deep-learning methods pave new ways in testing old theories and expanding what can be observed from new experiments. David Hatch, a research scientist at the Institute for Fusion Studies at the University of Texas at Austin, believes these applications are the start of a promising new technique.

      “Abhi’s work is a major achievement with the potential for broad application,” he says. “For example, given limited diagnostic measurements of a specific plasma quantity, physics-informed machine learning could infer additional plasma quantities in a nearby domain, thereby augmenting the information provided by a given diagnostic. The technique also opens new strategies for model validation.”

      Mathews sees exciting research ahead.

      “Translating these techniques into fusion experiments for real edge plasmas is one goal we have in sight, and work is currently underway,” he says. “But this is just the beginning.”

      Mathews was supported in this work by the Manson Benedict Fellowship, Natural Sciences and Engineering Research Council of Canada, and U.S. Department of Energy Office of Science under the Fusion Energy Sciences program.​ More

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      in Security

      MIT students explore food sustainability

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      As students approached the homestretch of the fall semester, many were focused on completing final projects and preparing for exams. During this time of year, some students may neglect their well-being to the point of skipping meals. To help alleviate end-of-term stress and to give students a delicious study break, the Food Security Action Team recently offered a group of first-year students the opportunity to join a food tour of Daily Table, a new grocer located in Cambridge’s Central Square.

      Seventeen students along with staff from Student Financial Services, Office of the First Year, and the Office of Sustainability led the group from the steps of 77 Massachusetts Avenue a few blocks down the street to Daily Table in Central Square. As part of participating in the program, students were given a $25 TechCash gift card to shop for grocery items during the trip. To make things even more fun, MIT staff created a recipe challenge to encourage students to work together on making their own variation of quesadillas.

      Healthy, affordable, sustainable

      At Daily Table, students were greeted by Celia Grant, director of community engagement and programs from Daily Table, who led them through a tour of the space and highlighted the history and model of the grocery store, as well as some of its unique features. Founded by former Trader Joe’s president Doug Rauch in 2015, Daily Table operates three retail stores in Dorchester, Roxbury, and Central Square, and a commissary kitchen in the Boston metro area. Two more stores are in the works: one in Mattapan and another in Salem. For added convenience, Daily Table also offers free grocery delivery within a two-mile radius of its three locations.

      The Daily Table’s ethos is that delicious and wholesome food should be available, accessible, and affordable for everyone. To achieve these goals, Daily Table provides a wide selection of fresh produce, nutritious grocery staples, and made-from-scratch prepared grab-n-go foods at affordable prices. “All of our products meet strict nutritional guidelines for sodium and sugar so that customers can make food choices based on their diets, not based on price,” says Grant.

      In addition to a large network of farmers, manufacturers, and distributors who supply food to their stores, Daily Table often recovers and rescues perfectly good food that would have otherwise been sent to landfills. Surplus food, packaging and/or label changes, and items with close expiration dates are often discarded by larger grocery stores in the supply chain. But Daily Table steps in to break this cycle of waste and sell these products to customers at a much lower cost. 

      The pandemic has uncovered how difficult it can be for individuals and families to budget for necessities like utilities, rent, and even food. Daily Table seeks to create a more sustainable future by providing access to more well-balanced, nutritious food. “Even before the pandemic, it was challenging for families on limited incomes to meet the nutrition needs of their families. Post-pandemic, this challenge has now encompassed even more households, even those that have never before been challenged in this way,” says Grant. “As winter moves through, and inflation increases, the need for more affordable food and nutrition will rise. Daily Table is prepared to help meet those needs, and more.” 

      Food resources at MIT

      Downstairs at the Daily Table Central Square store, MIT staff members led a discussion about the components of a sustainable food system at MIT and beyond, shared advice on how to budget for food, and offered tips on how to make grocery shopping or cooking fun with fellow classmates and peers. “Shopping at Daily Table provides an experiential case study in solving for multiple goals at once — from the environmental impacts of food waste to healthy eating to affordability — an important framework to consider when tackling climate challenges.” says Susy Jones, senior sustainability project manager in the MIT Office of Sustainability.

      The group also discussed budgeting expenses, including food. “By taking students to the grocery store and providing some small but meaningful tips, we provided them the opportunity to put their learning into practice!” says Erica Aguiar, associate director for financial education in Student Financial Services. “We saw students taking a closer look at prices and even coming together to share groceries.”

      MIT senior and DormCon Dining Chair Ashley Holton shared her grocery shopping strategies with the group, and how she utilizes resources available at MIT. “Having a plan before you enter the grocery store is really important,” says Holton. “Not only does it save time, but it helps you avoid potentially getting more than what your budget allows for, while also making sure you get all the food you’ll need.”

      This program, along with many others, is part of MIT’s larger effort on fostering a more food-secure and sustainable campus for all students. Food Security Action Team members, including students, staff, and campus partners, are striving to achieve this goal by ensuring that there continues to be a well-organized and coordinated action around food security that can be implemented effectively each year. For example, to make shopping at Daily Table even easier, MIT has made it a priority to ensure the store accepts TechCash.

      No MIT student should go hungry due to lack of money or resources, and no student should feel like they need to be “really hungry” to ask for help. MIT offers several other resources to help students find the nutrition and other support they need. In addition, the Office of Student Wellbeing launched their DoingWell website, which offers programs and resources to help students prioritize their well-being by practicing healthy habits and getting support when they need it.

      “In my own cost-analysis comparison of staple grocery items of all the local grocery stores, no other store comes close to being able to offer what Daily Table does for the prices it does. It’s really remarkable to learn and experience just how Daily Table is changing the food system,” says Holton. “Its model is one of the many ways that will continue to foster a more food-secure community where everyone — including MIT students — can access affordable, nutritious food.” More

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      in Environment

      Reducing food waste to increase access to affordable foods

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      About a third of the world’s food supply never gets eaten. That means the water, labor, energy, and fertilizer that went into growing, processing, and distributing the food is wasted.

      On the other end of the supply chain are cash-strapped consumers, who have been further distressed in recent years by factors like the Covid-19 pandemic and inflation.

      Spoiler Alert, a company founded by two MIT alumni, is helping companies bridge the gap between food waste and food insecurity with a platform connecting major food and beverage brands with discount grocers, retailers, and nonprofits. The platform helps brands discount or donate excess and short-dated inventory days, weeks, and months before it expires.

      “There is a tremendous amount of underutilized data that exists in the manufacturing and distribution space that results in good food going to waste,” says Ricky Ashenfelter MBA ’15, who co-founded the company with Emily Malina MBA ’15.

      Spoiler Alert helps brands manage distressed inventory data, create offers for potential buyers, and review and accept bids. The platform is designed to work with companies’ existing inventory and fulfillment systems, using automation and pricing intelligence to further streamline sales.

      “At a high level, we’re a waste-prevention software built for sales and supply-chain teams,” Ashenfelter says. “You can think of it as a private [business-to-business] eBay of sorts.”

      Spoiler Alert is working with global companies like Nestle, Kraft Heinz, and Danone, as well as discount grocers like the United Grocery Outlet and Misfits Market. Those brands are already using the platform to reduce food waste and get more food on people’s tables.

      “Project Drawdown [a nonprofit working on climate solutions] has identified food waste as the number one priority to address the global climate crisis, so these types of corporate initiatives can be really powerful from an environmental standpoint,” Ashenfelter says, noting the nonprofit estimates food waste accounts for 8 percent of global greenhouse gas emissions. “Contrast that with growing levels of food insecurity and folks not being able to access affordable nutrition, and you start to see how tackling supply-chain inefficiency can have a dramatic impact from both an environmental and a social lens. That’s what motivates us.”

      Untapped data for change

      Ashenfelter came to MIT’s Sloan School of Management after several years in sustainability software and management consulting within the retail and consumer products industries.

      “I was really attracted to transitioning into something much more entrepreneurial, and to leverage not only Sloan’s focus on entrepreneurship, but also the broader MIT ecosystem’s focus on technology, entrepreneurship, clean tech innovation, and other themes along that front,” he says.

      Ashenfelter met Malina at one of Sloan’s admitted students events in 2013, and the founders soon set out to use data to decrease food waste.

      “For us, the idea was clear: How do we better leverage data to manage excess and short-dated inventory?” Ashenfelter says. “How we go about that has evolved over the last six years, but it’s all rooted in solving an enormous climate problem, solving a major food insecurity problem, and from a capitalistic standpoint, helping businesses cut costs and generate revenue from otherwise wasted products.”

      The founders spent many hours in the Martin Trust Center for MIT Entrepreneurship with support from the Sloan Sustainability Initiative, and used Spoiler Alert as a case study in nearly every class they took, thinking through product development, sales, marketing, pricing, and more through their coursework.

      “We brought our idea into just about every action learning class that we could at Sloan and MIT,” Ashenfelter says.

      They also participated in the MIT $100K Entrepreneurship Competition and received support from the Venture Mentoring Service and the IDEAS Global Challenge program.

      Upon graduation, the founders initially began building a platform to facilitate donations of excess inventory, but soon learned big companies’ processes for discounting that inventory were also highly manual. Today, more than 90 percent of Spoiler Alert’s transaction volume is discounted, with the remainder donated.

      Different teams within an organization can upload excess inventory reports to Spoiler Alert’s system, eliminating the need to manually aggregate datasets and preparing what the industry refers to as “blowout lists” to sell. Spoiler Alert uses machine-learning-based tools to help both parties with pricing and negotiations to close deals more quickly.

      “Companies are taking pretty manual and slow approaches to deciding [what to do with excess inventory],” Ashenfelter says. “And when you have slow decision-making, you’re losing days or even weeks of shelf life on that product. That can be the difference between selling product versus donating, and donating versus dumping.”

      Once a deal has been made, Spoiler Alert automatically generates the forms and workflows needed by fulfillment teams to get the product out the door. The relationships companies build on the platform are also a major driver for cutting down waste.

      “We’re providing suppliers with the ability to control where their discounted and donated product ends up,” Ashenfelter says. “That’s really powerful because it allows these CPG brands to ensure that this product is, in many cases, getting to affordable nutrition outlets in underserved communities.”

      Ashenfelter says the majority of inventory goes to regional and national discount grocers, supplemented with extensive purchasing from local and nonprofit grocery chains.

      “Everything we do is oriented around helping sell as much product as possible to a reputable set of buyers at the most fair, equitable prices possible,” Ashenfelter says.

      Scaling for impact

      The pandemic has disrupted many aspects of the food supply chains. But Ashenfelter says it has also accelerated the adoption of digital solutions that can better manage such volatility.

      When Campbell began using Spoiler Alert’s system in 2019, for instance, it achieved a 36 percent increase in discount sales and a 27 percent increase in donations over the first five months.

      Ashenfelter says the results have proven that companies’ sustainability targets can go hand in hand with initiatives that boost their bottom lines. In fact, because Spoiler Alert focuses so much on the untapped revenue associated with food waste, many customers don’t even realize Spoiler Alert is a sustainability company until after they’ve signed on.

      “What’s neat about this program is that it becomes an incredibly powerful case study internally for how sustainability and operational outcomes aren’t in conflict and can drive both business results as well as overall environmental impact,” Ashenfelter says.

      Going forward, Spoiler Alert will continue building out algorithmic solutions that could further cut down on waste internationally and across a wider array of products.

      “At every step in our process, we’re collecting a tremendous amount of data in terms of what is and isn’t selling, at what price point, to which buyers, out of which geographies, and with how much remaining shelf life,” Ashenfelter explains. “We are only starting to scratch the surface in terms of bringing our recommendations engine to life for our suppliers and buyers. Ultimately our goal is to power the waste-free economy, and rooted in that is making better decisions faster, in collaboration with a growing ecosystem of supply chain partners, and with as little manual intervention as possible.” More

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      in Environment

      MIT community in 2021: A year in review

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      During 2021, the Covid-19 pandemic continued to color much of the year, as MIT saw both the promise of vaccines as well as the rise of troubling new variants. The Institute also made new commitments to climate action, saw the opening of new and renovated spaces, continued in its efforts to support its diverse voices, and celebrated new Nobel laureates and astronaut candidates. Here are some of the top stories in the MIT community this year.

      Continuing to work through CovidVaccines became widely available to the MIT community early in the year — thanks, in significant part, to the ingenuity of MIT scientists and engineers. In response, the Institute developed a policy requiring vaccination for most members of the community and planned a return to fully in-person teaching and working at MIT for the fall 2021 semester.

      With copious protections in place, the fall semester in many ways embodied MIT’s resilience: In-person teaching expanded, staff returned with new flexible arrangements, and community spirit lifted as face-to-face meetings became possible in many cases once again. Some annual traditions, such as Commencement, stayed remote, while others, like the outdoor Great Glass Pumpkin Patch, and 2.009 grand finale, returned, adding smiles and a sense of gratitude among community members.Melissa Nobles appointed chancellor

      In August, Melissa Nobles, the former Kenin Sahin Dean of the MIT School of Humanities, Arts, and Social Sciences, became the Institute’s new chancellor. A political scientist, Nobles succeeded Cynthia Barnhart, who returned to research and teaching after seven years as chancellor.

      In other news related to MIT’s top administration, Martin Schmidt announced in November that after 40 years at MIT, he plans to step down as provost to become the next president of Rensselaer Polytechnic Institute, his alma mater.

      New climate action plan

      MIT unveiled a new action plan to tackle the climate crisis, committing to net-zero emissions by 2026 and charting a course marshaling all of MIT’s capabilities toward decarbonization. The plan includes a broad array of new initiatives and significant expansions of existing programs to address the needs for new technologies, new policies, and new kinds of outreach to bring the Institute’s expertise to bear on this critical global issue.

      In November, a delegation from MIT also traveled to Scotland for COP26, the 2021 United Nations climate change conference, where international negotiators sought to keep global climate goals on track. Approximately 20 MIT faculty, staff, and students were on hand to observe the negotiations, share and conduct research, and launch new initiatives.

      MIT and Harvard transfer edX

      MIT and Harvard University announced in June that assets of edX, the nonprofit they launched in 2012 to provide an open online platform for university courses, would be acquired by the publicly-traded education technology company 2U, and reorganized as a public benefit company under the 2U umbrella. In exchange, 2U was set to transfer net proceeds from the $800 million transaction to a nonprofit organization, also led by MIT and Harvard, to explore the next generation of online education.

      Supporting our diverse communityAs an important step forward in MIT’s ongoing efforts to create a more welcoming and inclusive community, the Institute hired six new assistant deans, one in each school and in the MIT Schwarzman College of Computing, to serve as diversity, equity, and inclusion professionals. In addition, this week Institute Community and Equity Officer John Dozier provided an update on the Strategic Action Plan for Diversity, Equity, and Inclusion, the first draft of which was released in March.

      A community discussion also examined the complexities of Asian American and Pacific Islander identity and acceptance at MIT, while underscoring the need for collaborative work among groups to combat prejudice and create equity. The forum was held amid a string of violent assaults on Asian Americans in the U.S., which raised public awareness about anti-Asian discrimination. Meanwhile, Professor Emma Teng provided historic context for the crisis.

      Three with MIT ties win Nobel PrizesProfessor Joshua Angrist, whose influential work has enhanced rigorous empirical research in economics, shared half of the 2021 Nobel Prize in economic sciences with Guido Imbens of the Stanford Graduate School of Business; the other half went to David Card of the University of California at Berkeley.

      In addition, David Julius ’77, a professor at the University of California at San Francisco, shared the 2021 Nobel Prize in Physiology or Medicine with Ardem Patapoutian, a professor at the Scripps Research Institute, for their discoveries in how the body senses touch and temperature. And Maria Ressa, a journalist in the Philippines and digital fellow at the MIT Initiative on the Digital Economy, shared the 2021 Nobel Peace Prize with journalist Dmitry Muratov of Russia.

      National STEM leadersBefore taking office in January, President Joe Biden selected two MIT faculty leaders for top science and technology posts in his administration. Eric Lander, director of the Broad Institute and professor of biology, was named presidential science advisor and director of the Office of Science and Technology Policy. Maria Zuber, vice president for research and professor of earth, atmospheric, and planetary sciences, was named co-chair of the President’s Council of Advisors on Science and Technology (PCAST), along with Caltech chemical engineer Frances Arnold — the first women ever to co-chair PCAST.

      Paula Hammond, head of the Department of Chemical Engineering, was also chosen to serve as a member of PCAST. Earlier in the year, Hammond, along with chemical engineer Arup Chakraborty, was named an Institute Professor, the highest honor bestowed upon MIT faculty.

      Task Force 2021 final report

      MIT’s Task Force 2021 and Beyond, charged with reimagining the future of MIT, released its final report, 18 months after it began work in the shadow of the Covid-19 pandemic. The report offers 17 recommendations to strengthen and streamline MIT, and make the Institute more successful across its teaching, research, and innovation endeavors. In addition to a providing a substantive list of recommendations, the report suggests routes to implementation, and assigns one or more senior leaders or faculty governance committees with oversight, for every idea presented.

      Newly opened or reopened

      A number of facilities, new or newly redesigned, opened in 2021. These included a new MIT Welcome Center in Kendall Square; the new InnovationHQ, a hub for MIT entrepreneurship; the newly renovated and reimagined Hayden Library and courtyard; and the new MIT Press Bookstore. Two new student residences also opened, and the community welcomed programming from the Institute’s new outdoor open space.

      Students win an impressive number of distinguished fellowshipsAs always, MIT students continued to shine. This year, exceptional undergraduates were awarded Fulbright, Marshall, Mitchell, Rhodes, and Schwarzman scholarships.

      Remembering those we’ve lostAmong community members who died this year were William Dalzell, Sergio Dominguez, Gene Dresselhaus, Sow Hsin-Chen, Ronald Kurtz, Paul Lagacé, Shirley McBay, ChoKyun Rha, George Shultz, Isadore Singer, James Swan, and Jing Wang. A longer list of 2021 obituaries is available on MIT News.

      In Case You Missed It… 

      Additional top community stories of 2021 included NASA’s selection of three new alumni astronaut candidates; the announcement of the 2021 MIT Solve Global Challenges; the successful conclusion of the MIT Campaign for a Better World; a win for MIT in the American Solar Challenge; a look at chess at the Institute; a roundup of new books from MIT authors; and the introduction of STEM-focused young-adult graphic fiction from the MIT Press. More

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      in Environment

      Expanding the conversation about sustainability

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      Stacy Godfreey-Igwe sat in her dorm room at MIT, staring frantically at her phone. An unprecedented snowstorm had hit her hometown of Richardson, Texas, and she was having difficulty contacting her family. She felt worried and frustrated, aware that nearby neighborhoods hadn’t lost power during the storm but that her family home had suffered significant damage. She finally got a hold of her parents, who had taken refuge in a nearby office building, but the experience left her shaken and more determined than ever to devote herself to addressing climate injustice.

      Godfreey-Igwe, the daughter of Nigerian immigrants, has long been concerned about how marginalized communities can shoulder a disproportionately heavy environmental burden. At MIT, she chose a double major in mechanical engineering with a concentration in global and sustainable development, and in African and African diaspora studies, a major she helped establish and became the first student to declare. Initially seeing the two fields as separate, she now embraces their intersectionality in her work in and out of the classroom.

      Through an Undergraduate Research Opportunity Program (UROP) project with Amah Edoh, the Homer A. Burnell Assistant Professor of Anthropology and African Studies at MIT, Godfreey-Igwe has learned more about her Igbo cultural heritage and hopes to understand what the future of climate change poses for the culture’s sustainability. Godfreey-Igwe herself is the “Ada” – or eldest child – in her family, a role that carries a responsibility for keeping her family’s culture alive. That sense of responsibility, to her community and to future generations, has stayed with her at MIT.

      For Independent Activities Period during her first year at the Institute, Godfreey-Igwe traveled to Kazakhstan through MIT’s Global Teaching Labs. As a student teacher, she taught Kazakh high school chemistry students about polymers and the impact plastic materials can have on the Earth’s climate. She was also an MIT International Science and Technology Initiatives (MISTI) Identity X Ambassador during her time there, blogging about her experiences as a Black woman in the country. She saw the role as an opportunity to shed light on the challenges of navigating her identity abroad, with hopes of fostering community through her posts.

      The following summer, Godfreey-Igwe interned for the Saathi Biodegradable Sanitary Napkins Startup in Ahmedabad, India. During her time there, she researched and wrote articles focused on educating the public about the benefits eco-friendly sanitary pads posed to public health and the environment. She also interviewed a director for the city’s Center for Environmental Education, about the importance of uplifting and supporting marginalized communities hit hardest by climate change. The conversation was eye-opening for Godfreey-Igwe; she saw not only how complex the process of mitigating climate change was, but also how diverse the solutions needed to be.

      She has also pursued her interest in plastics and sustainability through summer research projects. In of the summer of 2020, Godfreey-Igwe worked under a lab in Stanford University’s civil and environmental engineering department to create and design models maximizing the efficiency of bacterial processes leading to the creation of bioplastics. The project’s goal was to find a sustainable form of plastic breakdown for future applications in the environment.  She presented her research at the Harvard National Collegiate Research Conference and received a presentation award during the MIT Mechanical Engineering Research Exhibition. This past summer, she was awarded a grant through the NSF Center for Sustainable Polymers at the University of Minnesota to work on a research project seeking to understand microplastic generation.

      Ultimately, Godfreey-Igwe recognizes that to propose thoughtful solutions to climate issues, the people hit hardest must be a part of the conversation. For her, a key way to bring more people into conversations about sustainability and inclusion is through mentorship. This role is especially meaningful to Godfreey-Igwe because she knows firsthand how important for members of underrepresented groups to feel supported at a place like MIT. “The experience of coming to an institution like MIT, as someone who is low-income or of color, can be isolating. Especially if you feel like there are people who can’t relate to your background,” she says.

      Godfreey-Igwe is a member of Active Community Engagement FPOP (ACE), a social action group on campus that engages with local communities through public service work. Initially joining as a participant, Godfreey-Igwe became a counselor and then coordinator; she facilitates social action workshops and introduces students to service opportunities both at MIT and around Boston. She says her time in ACE has helped build her confidence in her abilities as a leader, mentor, and cultivator of inclusionary spaces. She is also a member of iHouse (International Development House), where she served for three years as the housing and service co-chair.

      Godfreey-Igwe also tutors one-on-one for Tutoring Plus in Cambridge, where since her first year she has provided mentorship and STEM tutoring to a low-income, high school student of color. Last spring, she was awarded the Tutoring Plus of Cambridge Unwavering Service Award for her service and commitment to the program.

      Looking ahead, Godfreey-Igwe hopes to use the skills learned from her mentorship and leadership roles to establish greater structures for collaboration on climate mitigation technologies, ideas, and practices. Focusing on mentoring young scientists of color, she wants to build up underprivileged groups and institutions for sustainable climate change research, ensuring everyone has a voice in the ongoing conversation.

      “In all this work, I’m hoping to make sure that globally marginalized communities are more visible in climate-related spaces, both in terms of who is doing the engineering and who the engineering works for,” she says. More

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      in Environment

      Selective separation could help alleviate critical metals shortage

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      New processing methods developed by MIT researchers could help ease looming shortages of the essential metals that power everything from phones to automotive batteries, by making it easier to separate these rare metals from mining ores and recycled materials.

      Selective adjustments within a chemical process called sulfidation allowed professor of metallurgy Antoine Allanore and his graduate student Caspar Stinn to successfully target and separate rare metals, such as the cobalt in a lithium-ion battery, from mixed-metal materials.

      As they report in the journal Nature, their processing techniques allow the metals to remain in solid form and be separated without dissolving the material. This avoids traditional but costly liquid separation methods that require significant energy. The researchers developed processing conditions for 56 elements and tested these conditions on 15 elements.

      Their sulfidation approach, they write in the paper, could reduce the capital costs of metal separation between 65 and 95 percent from mixed-metal oxides. Their selective processing could also reduce greenhouse gas emissions by 60 to 90 percent compared to traditional liquid-based separation.

      “We were excited to find replacements for processes that had really high levels of water usage and greenhouse gas emissions, such as lithium-ion battery recycling, rare-earth magnet recycling, and rare-earth separation,” says Stinn. “Those are processes that make materials for sustainability applications, but the processes themselves are very unsustainable.”

      The findings offer one way to alleviate a growing demand for minor metals like cobalt, lithium, and rare earth elements that are used in “clean” energy products like electric cars, solar cells, and electricity-generating windmills. According to a 2021 report by the International Energy Agency, the average amount of minerals needed for a new unit of power generation capacity has risen by 50 percent since 2010, as renewable energy technologies using these metals expand their reach.

      Opportunity for selectivity

      For more than a decade, the Allanore group has been studying the use of sulfide materials in developing new electrochemical routes for metal production. Sulfides are common materials, but the MIT scientists are experimenting with them under extreme conditions like very high temperatures — from 800 to 3,000 degrees Fahrenheit — that are used in manufacturing plants but not in a typical university lab.

      “We are looking at very well-established materials in conditions that are uncommon compared to what has been done before,” Allanore explains, “and that is why we are finding new applications or new realities.”

      In the process of synthetizing high-temperature sulfide materials to support electrochemical production, Stinn says, “we learned we could be very selective and very controlled about what products we made. And it was with that understanding that we realized, ‘OK, maybe there’s an opportunity for selectivity in separation here.’”

      The chemical reaction exploited by the researchers reacts a material containing a mix of metal oxides to form new metal-sulfur compounds or sulfides. By altering factors like temperature, gas pressure, and the addition of carbon in the reaction process, Stinn and Allanore found that they could selectively create a variety of sulfide solids that can be physically separated by a variety of methods, including crushing the material and sorting different-sized sulfides or using magnets to separate different sulfides from one another.

      Current methods of rare metal separation rely on large quantities of energy, water, acids, and organic solvents which have costly environmental impacts, says Stinn. “We are trying to use materials that are abundant, economical, and readily available for sustainable materials separation, and we have expanded that domain to now include sulfur and sulfides.”

      Stinn and Allanore used selective sulfidation to separate out economically important metals like cobalt in recycled lithium-ion batteries. They also used their techniques to separate dysprosium — a rare-earth element used in applications ranging from data storage devices to optoelectronics — from rare-earth-boron magnets, or from the typical mixture of oxides available from mining minerals such as bastnaesite.

      Leveraging existing technology

      Metals like cobalt and rare earths are only found in small amounts in mined materials, so industries must process large volumes of material to retrieve or recycle enough of these metals to be economically viable, Allanore explains. “It’s quite clear that these processes are not efficient. Most of the emissions come from the lack of selectivity and the low concentration at which they operate.”

      By eliminating the need for liquid separation and the extra steps and materials it requires to dissolve and then reprecipitate individual elements, the MIT researchers’ process significantly reduces the costs incurred and emissions produced during separation.

      “One of the nice things about separating materials using sulfidation is that a lot of existing technology and process infrastructure can be leveraged,” Stinn says. “It’s new conditions and new chemistries in established reactor styles and equipment.”

      The next step is to show that the process can work for large amounts of raw material — separating out 16 elements from rare-earth mining streams, for example. “Now we have shown that we can handle three or four or five of them together, but we have not yet processed an actual stream from an existing mine at a scale to match what’s required for deployment,” Allanore says.

      Stinn and colleagues in the lab have built a reactor that can process about 10 kilograms of raw material per day, and the researchers are starting conversations with several corporations about the possibilities.

      “We are discussing what it would take to demonstrate the performance of this approach with existing mineral and recycling streams,” Allanore says.

      This research was supported by the U.S. Department of Energy and the U.S. National Science Foundation. More

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      in Energy

      Q&A: Can the world change course on climate?

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      In this ongoing series on climate issues, MIT faculty, students, and alumni in the humanistic fields share perspectives that are significant for solving climate change and mitigating its myriad social and ecological impacts. Nazli Choucri is a professor of political science and an expert on climate issues, who also focuses on international relations and cyberpolitics. She is the architect and director of the Global System for Sustainable Development, an evolving knowledge networking system centered on sustainability problems and solution strategies. The author and/or editor of 12 books, she is also the founding editor of the MIT Press book series “Global Environmental Accord: Strategies for Sustainability and Institutional Innovation.” Q: The impacts of climate change — including storms, floods, wildfires, and droughts — have the potential to destabilize nations, yet they are not constrained by borders. What international developments most concern you in terms of addressing climate change and its myriad ecological and social impacts?

      A: Climate change is a global issue. By definition, and a long history of practice, countries focus on their own priorities and challenges. Over time, we have seen the gradual development of norms reflecting shared interests, and the institutional arrangements to support and pursue the global good. What concerns me most is that general responses to the climate crisis are being framed in broad terms; the overall pace of change remains perilously slow; and uncertainty remains about operational action and implementation of stated intent. We have just seen the completion of the 26th meeting of states devoted to climate change, the United Nations Climate Change Conference (COP26). In some ways this is positive. Yet, past commitments remain unfulfilled, creating added stress in an already stressful political situation. Industrial countries are uneven in their recognition of, and responses to, climate change. This may signal uncertainty about whether climate matters are sufficiently compelling to call for immediate action. Alternatively, the push for changing course may seem too costly at a time when other imperatives — such as employment, economic growth, or protecting borders — inevitably dominate discourse and decisions. Whatever the cause, the result has been an unwillingness to take strong action. Unfortunately, climate change remains within the domain of “low politics,” although there are signs the issue is making a slow but steady shift to “high politics” — those issues deemed vital to the existence of the state. This means that short-term priorities, such as those noted above, continue to shape national politics and international positions and, by extension, to obscure the existential threat revealed by scientific evidence. As for developing countries, these are overwhelmed by internal challenges, and managing the difficulties of daily life always takes priority over other challenges, however compelling. Long-term thinking is a luxury, but daily bread is a necessity. Non-state actors — including registered nongovernmental organizations, climate organizations, sustainability support groups, activists of various sorts, and in some cases much of civil society — have been left with a large share of the responsibility for educating and convincing diverse constituencies of the consequences of inaction on climate change. But many of these institutions carry their own burdens and struggle to manage current pressures. The international community, through its formal and informal institutions, continues to articulate the perils of climate change and to search for a powerful consensus that can prove effective both in form and in function. The general contours are agreed upon — more or less. But leadership of, for, and by the global collective is elusive and difficult to shape. Most concerning of all is the clear reluctance to address head-on the challenge of planning for changes that we know will occur. The reality that we are all being affected — in different ways and to different degrees — has yet to be sufficiently appreciated by everyone, everywhere. Yet, in many parts of the world, major shifts in climate will create pressures on human settlements, spur forced migrations, or generate social dislocations. Some small island states, for example, may not survive a sea-level surge. Everywhere there is a need to cut emissions, and this means adaptation and/or major changes in economic activity and in lifestyle.The discourse and debate at COP26 reflect all of such persistent features in the international system. So far, the largest achievements center on the common consensus that more must be done to prevent the rise in temperature from creating a global catastrophe. This is not enough, however. Differences remain, and countries have yet to specify what cuts in emissions they are willing to make.Echoes of who is responsible for what remains strong. The thorny matter of the unfulfilled pledge of $100 billion once promised by rich countries to help countries to reduce their emissions remained unresolved. At the same time, however, some important agreements were reached. The United States and China announced they would make greater efforts to cut methane, a powerful greenhouse gas. More than 100 countries agreed to end deforestation. India joined the countries committed to attain zero emissions by 2070. And on matters of finance, countries agreed to a two-year plan to determine how to meet the needs of the most-vulnerable countries. Q: In what ways do you think the tools and insights from political science can advance efforts to address climate change and its impacts?A: I prefer to take a multidisciplinary view of the issues at hand, rather than focus on the tools of political science alone. Disciplinary perspectives can create siloed views and positions that undermine any overall drive toward consensus. The scientific evidence is pointing to, even anticipating, pervasive changes that transcend known and established parameters of social order all across the globe.That said, political science provides important insight, even guidance, for addressing the impacts of climate change in some notable ways. One is understanding the extent to which our formal institutions enable discussion, debate, and decisions about the directions we can take collectively to adapt, adjust, or even depart from the established practices of managing social order.If we consider politics as the allocation of values in terms of who gets what, when, and how, then it becomes clear that the current allocation requires a change in course. Coordination and cooperation across the jurisdictions of sovereign states is foundational for any response to climate change impacts.We have already recognized, and to some extent, developed targets for reducing carbon emissions — a central impact from traditional forms of energy use — and are making notable efforts to shift toward alternatives. This move is an easy one compared to all the work that needs to be done to address climate change. But, in taking this step we have learned quite a bit that might help in creating a necessary consensus for cross-jurisdiction coordination and response.Respecting individuals and protecting life is increasingly recognized as a global value — at least in principle. As we work to change course, new norms will be developed, and political science provides important perspectives on how to establish such norms. We will be faced with demands for institutional design, and these will need to embody our guiding values. For example, having learned to recognize the burdens of inequity, we can establish the value of equity as foundational for our social order both now and as we recognize and address the impacts of climate change.

      Q: You teach a class on “Sustainability Development: Theory and Practice.” Broadly speaking, what are goals of this class? What lessons do you hope students will carry with them into the future?A: The goal of 17.181, my class on sustainability, is to frame as clearly as possible the concept of sustainable development (sustainability) with attention to conceptual, empirical, institutional, and policy issues.The course centers on human activities. Individuals are embedded in complex interactive systems: the social system, the natural environment, and the constructed cyber domain — each with distinct temporal, special, and dynamic features. Sustainability issues intersect with, but cannot be folded into, the impacts of climate change. Sustainability places human beings in social systems at the core of what must be done to respect the imperatives of a highly complex natural environment.We consider sustainability an evolving knowledge domain with attendant policy implications. It is driven by events on the ground, not by revolution in academic or theoretical concerns per se. Overall, sustainable development refers to the process of meeting the needs of current and future generations, without undermining the resilience of the life-supporting properties, the integrity of social systems, or the supports of the human-constructed cyberspace.More specifically, we differentiate among four fundamental dimensions and their necessary conditions:

      (a) ecological systems — exhibiting balance and resilience;(b) economic production and consumption — with equity and efficiency;(c) governance and politics — with participation and responsiveness; and(d) institutional performance — demonstrating adaptation and incorporating feedback.The core proposition is this: If all conditions hold, then the system is (or can be) sustainable. Then, we must examine the critical drivers — people, resources, technology, and their interactions — followed by a review and assessment of evolving policy responses. Then we ask: What are new opportunities?I would like students to carry forward these ideas and issues: what has been deemed “normal” in modern Western societies and in developing societies seeking to emulate the Western model is damaging humans in many ways — all well-known. Yet only recently have alternatives begun to be considered to the traditional economic growth model based on industrialization and high levels of energy use. To make changes, we must first understand the underlying incentives, realities, and choices that shape a whole set of dysfunctional behaviors and outcomes. We then need to delve deep into the driving sources and consequences, and to consider the many ways in which our known “normal” can be adjusted — in theory and in practice. Q: In confronting an issue as formidable as global climate change, what gives you hope?  A: I see a few hopeful signs; among them:The scientific evidence is clear and compelling. We are no longer discussing whether there is climate change, or if we will face major challenges of unprecedented proportions, or even how to bring about an international consensus on the salience of such threats.Climate change has been recognized as a global phenomenon. Imperatives for cooperation are necessary. No one can go it alone. Major efforts have and are being made in world politics to forge action agendas with specific targets.The issue appears to be on the verge of becoming one of “high politics” in the United States.Younger generations are more sensitive to the reality that we are altering the life-supporting properties of our planet. They are generally more educated, skilled, and open to addressing such challenges than their elders.However disappointing the results of COP26 might seem, the global community is moving in the right direction.None of the above points, individually or jointly, translates into an effective response to the known impacts of climate change — let alone the unknown. But, this is what gives me hope.

      Interview prepared by MIT SHASS CommunicationsEditorial, design, and series director: Emily HiestandSenior writer: Kathryn O’Neill More

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      in Environment

      A tool to speed development of new solar cells

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      In the ongoing race to develop ever-better materials and configurations for solar cells, there are many variables that can be adjusted to try to improve performance, including material type, thickness, and geometric arrangement. Developing new solar cells has generally been a tedious process of making small changes to one of these parameters at a time. While computational simulators have made it possible to evaluate such changes without having to actually build each new variation for testing, the process remains slow.

      Now, researchers at MIT and Google Brain have developed a system that makes it possible not just to evaluate one proposed design at a time, but to provide information about which changes will provide the desired improvements. This could greatly increase the rate for the discovery of new, improved configurations.

      The new system, called a differentiable solar cell simulator, is described in a paper published today in the journal Computer Physics Communications, written by MIT junior Sean Mann, research scientist Giuseppe Romano of MIT’s Institute for Soldier Nanotechnologies, and four others at MIT and at Google Brain.

      Traditional solar cell simulators, Romano explains, take the details of a solar cell configuration and produce as their output a predicted efficiency — that is, what percentage of the energy of incoming sunlight actually gets converted to an electric current. But this new simulator both predicts the efficiency and shows how much that output is affected by any one of the input parameters. “It tells you directly what happens to the efficiency if we make this layer a little bit thicker, or what happens to the efficiency if we for example change the property of the material,” he says.

      In short, he says, “we didn’t discover a new device, but we developed a tool that will enable others to discover more quickly other higher performance devices.” Using this system, “we are decreasing the number of times that we need to run a simulator to give quicker access to a wider space of optimized structures.” In addition, he says, “our tool can identify a unique set of material parameters that has been hidden so far because it’s very complex to run those simulations.”

      While traditional approaches use essentially a random search of possible variations, Mann says, with his tool “we can follow a trajectory of change because the simulator tells you what direction you want to be changing your device. That makes the process much faster because instead of exploring the entire space of opportunities, you can just follow a single path” that leads directly to improved performance.

      Since advanced solar cells often are composed of multiple layers interlaced with conductive materials to carry electric charge from one to the other, this computational tool reveals how changing the relative thicknesses of these different layers will affect the device’s output. “This is very important because the thickness is critical. There is a strong interplay between light propagation and the thickness of each layer and the absorption of each layer,” Mann explains.

      Other variables that can be evaluated include the amount of doping (the introduction of atoms of another element) that each layer receives, or the dielectric constant of insulating layers, or the bandgap, a measure of the energy levels of photons of light that can be captured by different materials used in the layers.

      This simulator is now available as an open-source tool that can be used immediately to help guide research in this field, Romano says. “It is ready, and can be taken up by industry experts.” To make use of it, researchers would couple this device’s computations with an optimization algorithm, or even a machine learning system, to rapidly assess a wide variety of possible changes and home in quickly on the most promising alternatives.

      At this point, the simulator is based on just a one-dimensional version of the solar cell, so the next step will be to expand its capabilities to include two- and three-dimensional configurations. But even this 1D version “can cover the majority of cells that are currently under production,” Romano says. Certain variations, such as so-called tandem cells using different materials, cannot yet be simulated directly by this tool, but “there are ways to approximate a tandem solar cell by simulating each of the individual cells,” Mann says.

      The simulator is “end-to-end,” Romano says, meaning it computes the sensitivity of the efficiency, also taking into account light absorption. He adds: “An appealing future direction is composing our simulator with advanced existing differentiable light-propagation simulators, to achieve enhanced accuracy.”

      Moving forward, Romano says, because this is an open-source code, “that means that once it’s up there, the community can contribute to it. And that’s why we are really excited.” Although this research group is “just a handful of people,” he says, now anyone working in the field can make their own enhancements and improvements to the code and introduce new capabilities.

      “Differentiable physics is going to provide new capabilities for the simulations of engineered systems,” says Venkat Viswanathan, an associate professor of mechanical engineering at Carnegie Mellon University, who was not associated with this work. “The  differentiable solar cell simulator is an incredible example of differentiable physics, that can now provide new capabilities to optimize solar cell device performance,” he says, calling the study “an exciting step forward.”

      In addition to Mann and Romano, the team included Eric Fadel and Steven Johnson at MIT, and Samuel Schoenholz and Ekin Cubuk at Google Brain. The work was supported in part by Eni S.p.A. and the MIT Energy Initiative, and the MIT Quest for Intelligence. More