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      in Energy

      A new mathematical “blueprint” is accelerating fusion device development

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      Developing commercial fusion energy requires scientists to understand sustained processes that have never before existed on Earth. But with so many unknowns, how do we make sure we’re designing a device that can successfully harness fusion power?

      We can fill gaps in our understanding using computational tools like algorithms and data simulations to knit together experimental data and theory, which allows us to optimize fusion device designs before they’re built, saving much time and resources.

      Currently, classical supercomputers are used to run simulations of plasma physics and fusion energy scenarios, but to address the many design and operating challenges that still remain, more powerful computers are a necessity, and of great interest to plasma researchers and physicists.

      Quantum computers’ exponentially faster computing speeds have offered plasma and fusion scientists the tantalizing possibility of vastly accelerated fusion device development. Quantum computers could reconcile a fusion device’s many design parameters — for example, vessel shape, magnet spacing, and component placement — at a greater level of detail, while also completing the tasks faster. However, upgrading to a quantum computer is no simple task.

      In a paper, “Dyson maps and unitary evolution for Maxwell equations in tensor dielectric media,” recently published in Physics Review A, Abhay K. Ram, a research scientist at the MIT Plasma Science and Fusion Center (PSFC), and his co-authors Efstratios Koukoutsis, Kyriakos Hizanidis, and George Vahala present a framework that would facilitate the use of quantum computers to study electromagnetic waves in plasma and its manipulation in magnetic confinement fusion devices.

      Quantum computers excel at simulating quantum physics phenomena, but many topics in plasma physics are predicated on the classical physics model. A plasma (which is the “dielectric media” referenced in the paper’s title) consists of many particles — electrons and ions — the collective behaviors of which are effectively described using classic statistical physics. In contrast, quantum effects that influence atomic and subatomic scales are averaged out in classical plasma physics.  

      Furthermore, the descriptive limitations of quantum mechanics aren’t suited to plasma. In a fusion device, plasmas are heated and manipulated using electromagnetic waves, which are one of the most important and ubiquitous occurrences in the universe. The behaviors of electromagnetic waves, including how waves are formed and interact with their surroundings, are described by Maxwell’s equations — a foundational component of classical plasma physics, and of general physics as well. The standard form of Maxwell’s equations is not expressed in “quantum terms,” however, so implementing the equations on a quantum computer is like fitting a square peg in a round hole: it doesn’t work.

      Consequently, for plasma physicists to take advantage of quantum computing’s power for solving problems, classical physics must be translated into the language of quantum mechanics. The researchers tackled this translational challenge, and in their paper, they reveal that a Dyson map can bridge the translational divide between classical physics and quantum mechanics. Maps are mathematical functions that demonstrate how to take an input from one kind of space and transform it to an output that is meaningful in a different kind of space. In the case of Maxwell’s equations, a Dyson map allows classical electromagnetic waves to be studied in the space utilized by quantum computers. In essence, it reconfigures the square peg so it will fit into the round hole without compromising any physics.

      The work also gives a blueprint of a quantum circuit encoded with equations expressed in quantum bits (“qubits”) rather than classical bits so the equations may be used on quantum computers. Most importantly, these blueprints can be coded and tested on classical computers.

      “For years we have been studying wave phenomena in plasma physics and fusion energy science using classical techniques. Quantum computing and quantum information science is challenging us to step out of our comfort zone, thereby ensuring that I have not ‘become comfortably numb,’” says Ram, quoting a Pink Floyd song.

      The paper’s Dyson map and circuits have put quantum computing power within reach, fast-tracking an improved understanding of plasmas and electromagnetic waves, and putting us that much closer to the ideal fusion device design.    More

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      in Environment

      Advancing material innovation to address the polymer waste crisis

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      Products made from polymers — ranging from plastic bags to clothing to cookware to electronics — provide many comforts and support today’s standard of living, but since they do not decompose easily, they pose long-term environmental challenges. Developing polymers, a large class of materials, with a more sustainable life cycle is a critical step in making progress toward a green economy and addressing this piece of the global climate change crisis. The development of biodegradable polymers, however, remains limited by current biodegradation testing methods.

      To address this limitation, a team of MIT researchers led by Bradley D. Olsen, the Alexander and I. Michael Kasser (1960) Professor in the Department of Chemical Engineering, has developed an expansive biodegradation dataset to help determine whether or not a polymer is biodegradable.

      Their findings were recently published in The Proceedings of the National Academy of Sciences (PNAS), a peer reviewed journal of the National Academy of Sciences (NAS), in a paper titled “High-Throughput Experimentation for Discovery of Biodegradable Polyesters.” The MIT team is led by Olsen and PhD candidates Katharina A. Fransen and Sarah H. M. Av-Ron, and also includes postdoc Dylan J. Walsh and undergraduate students Tess R. Buchanan, Dechen T. Rota, and Lana Van Note.

      “Despite polymer waste being a known and significant contributor to the climate crisis, the study of polymer biodegradation has been limited to a small number of polymers because current biodegradation testing methods are time- and resource-intensive,” says Olsen. “This limited scope slows new material innovation, so we are working to open that up to a much broader portfolio of materials.”

      Unique high-throughput approach

      The dataset Olsen’s team has developed, with support from the MIT Climate and Sustainability Consortium (MCSC), the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), and DIC Corporation, includes more than 600 distinct polyester chemistries.

      “The ingenuity of our work is pushing the screening to be high-throughput, which accelerates the pace of discovery,” says Av-Ron. High-throughput synthesis methods enable large quantities of samples to be screened rapidly, identifying products with the desired property or function you are looking for. In this case, the high-throughput approach was conducted using a method called clear-zone assay, which detects polymer biofragmentation and identifies polymer degrading bacteria. The biodegradation dataset can then lead to structure-property relationships, a concept central to materials science and engineering, where relationships between the chemical detail and property can be established, and used to build a biodegradation prediction model. When developing these models to predict biodegradation, the researchers were interested in looking into the potential linearity and nonlinearity of the relationships between structure and biodegradability.

      “We consider our scientific breakthrough to be having this large dataset, and the qualitative relationships and predictive models such a substantial  amount of data enabled,” adds Av-Ron. “It was captivating to figure out how to integrate the high complexity of polymer chemical representation with predictive machine-learning models. I was very excited to get a validation accuracy of 82 percent for one representation/model combination. With additional data we might be able to improve our predictions even more.”

      The team’s work focuses largely on polyesters; the development of biodegradable polyesters presents a key opportunity for addressing the polymer sustainability crisis and reducing the environmental burden of the polymer life cycle.

      One strain of bacteria, many chemistries

      The biodegradation test that these data create is accessible and cost-effective to put in place; initial industry feedback has been positive. The datasets are also more reproducible than many other standards in this space.

      “With our method, there is one strain of bacteria, so you know exactly what you’re testing,” says Av-Ron. This speaks to the uniqueness of the team’s approach.

      “When polymers are developed, normally the strength of the material is examined first, and then once the material is developed, whether or not it biodegrades comes second,” says Fransen.

      Olsen and his team are examining the opposite — developing the biodegradability screen first, to help filter and focus what to look for in a material. This way, the team’s infrastructure can assess a lot of different options, quickly.

      “There has been big movement recently in developing sustainable polymers,” concludes Fransen, “and having something like this that is quick, tangible, and relatively inexpensive, could add a lot of value to that community.”

      Fransen received a 2022 J-WAFS Fellowship for this work, and she and Av-Ron together won second place in the 2022 J-WAFS World Food Day Student Video Competition, as this research can be applied to creating more sustainable food packaging. More

    • 138 Shares129 Views

      in Environment

      Megawatt electrical motor designed by MIT engineers could help electrify aviation

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      Aviation’s huge carbon footprint could shrink significantly with electrification. To date, however, only small all-electric planes have gotten off the ground. Their electric motors generate hundreds of kilowatts of power. To electrify larger, heavier jets, such as commercial airliners, megawatt-scale motors are required. These would be propelled by hybrid or turbo-electric propulsion systems where an electrical machine is coupled with a gas turbine aero-engine.

      To meet this need, a team of MIT engineers is now creating a 1-megawatt motor that could be a key stepping stone toward electrifying larger aircraft. The team has designed and tested the major components of the motor, and shown through detailed computations that the coupled components can work as a whole to generate one megawatt of power, at a weight and size competitive with current small aero-engines.

      For all-electric applications, the team envisions the motor could be paired with a source of electricity such as a battery or a fuel cell. The motor could then turn the electrical energy into mechanical work to power a plane’s propellers. The electrical machine could also be paired with a traditional turbofan jet engine to run as a hybrid propulsion system, providing electric propulsion during certain phases of a flight.

      “No matter what we use as an energy carrier — batteries, hydrogen, ammonia, or sustainable aviation fuel — independent of all that, megawatt-class motors will be a key enabler for greening aviation,” says Zoltan Spakovszky, the T. Wilson Professor in Aeronautics and the Director of the Gas Turbine Laboratory (GTL) at MIT, who leads the project.

      Spakovszky and members of his team, along with industry collaborators, will present their work at a special session of the American Institute of Aeronautics and Astronautics – Electric Aircraft Technologies Symposium (EATS) at the Aviation conference in June.

      The MIT team is composed of faculty, students, and research staff from GTL and the MIT Laboratory for Electromagnetic and Electronic Systems: Henry Andersen Yuankang Chen, Zachary Cordero, David Cuadrado,  Edward Greitzer, Charlotte Gump, James Kirtley, Jr., Jeffrey Lang, David Otten, David Perreault, and Mohammad Qasim,  along with Marc Amato of Innova-Logic LLC. The project is sponsored by Mitsubishi Heavy Industries (MHI).

      Heavy stuff

      To prevent the worst impacts from human-induced climate change, scientists have determined that global emissions of carbon dioxide must reach net zero by 2050. Meeting this target for aviation, Spakovszky says, will require “step-change achievements” in the design of unconventional aircraft, smart and flexible fuel systems, advanced materials, and safe and efficient electrified propulsion. Multiple aerospace companies are focused on electrified propulsion and the design of megawatt-scale electric machines that are powerful and light enough to propel passenger aircraft.

      “There is no silver bullet to make this happen, and the devil is in the details,” Spakovszky says. “This is hard engineering, in terms of co-optimizing individual components and making them compatible with each other while maximizing overall performance. To do this means we have to push the boundaries in materials, manufacturing, thermal management, structures and rotordynamics, and power electronics”

      Broadly speaking, an electric motor uses electromagnetic force to generate motion. Electric motors, such as those that power the fan in your laptop, use electrical energy — from a battery or power supply — to generate a magnetic field, typically through copper coils. In response, a magnet, set near the coils, then spins in the direction of the generated field and can then drive a fan or propeller.

      Electric machines have been around for over 150 years, with the understanding that, the bigger the appliance or vehicle, the larger the copper coils  and the magnetic rotor, making the machine heavier. The more power the electrical machine generates, the more heat it produces, which requires additional elements to keep the components cool — all of which can take up space and add significant weight to the system, making it challenging for airplane applications.

      “Heavy stuff doesn’t go on airplanes,” Spakovszky says. “So we had to come up with a compact, lightweight, and powerful architecture.”

      Good trajectory

      As designed, the MIT electric motor and power electronics are each about the size of a checked suitcase weighing less than an adult passenger.

      The motor’s main components are: a high-speed rotor, lined with an array of magnets with varying orientation of polarity; a compact low-loss stator that fits inside the rotor and contains an intricate array of copper windings; an advanced heat exchanger that keeps the components cool while transmitting the torque of the machine; and a distributed power electronics system, made from 30 custom-built circuit boards, that precisely change the currents running through each of the stator’s copper windings, at high frequency.

      “I believe this is the first truly co-optimized integrated design,” Spakovszky says. “Which means we did a very extensive design space exploration where all considerations from thermal management, to rotor dynamics, to power electronics and electrical machine architecture were assessed in an integrated way to find out what is the best possible combination to get the required specific power at one megawatt.”

      As a whole system, the motor is designed such that the distributed circuit boards are close coupled with the electrical machine to minimize transmission loss and to allow effective air cooling through the integrated heat exchanger.

      “This is a high-speed machine, and to keep it rotating while creating torque, the magnetic fields have to be traveling very quickly, which we can do through our circuit boards switching at high frequency,” Spakovszky says.

      To mitigate risk, the team has built and tested each of the major components individually, and shown that they can operate as designed and at conditions exceeding normal operational demands. The researchers plan to assemble the first fully working electric motor, and start testing it in the fall.

      “The electrification of aircraft has been on a steady rise,” says Phillip Ansell, director of the Center for Sustainable Aviation at the University of Illinois Urbana-Champaign, who was not involved in the project. “This group’s design uses a wonderful combination of conventional and cutting-edge methods for electric machine development, allowing it to offer both robustness and efficiency to meet the practical needs of aircraft of the future.”

      Once the MIT team can demonstrate the electric motor as a whole, they say the design could power regional aircraft and could also be a companion to conventional jet engines, to enable hybrid-electric propulsion systems. The team also envision that multiple one-megawatt motors could power multiple fans distributed along the wing on future aircraft configurations. Looking ahead, the foundations of the one-megawatt electrical machine design could potentially be scaled up to multi-megawatt motors, to power larger passenger planes.

      “I think we’re on a good trajectory,” says Spakovszky, whose group and research have focused on more than just gas turbines. “We are not electrical engineers by training, but addressing the 2050 climate grand challenge is of utmost importance; working with electrical engineering faculty, staff and students for this goal can draw on MIT’s breadth of technologies so the whole is greater than the sum of the parts. So we are reinventing ourselves in new areas. And MIT gives you the opportunity to do that.” More

    • 100 Shares99 Views

      in Environment

      River erosion can shape fish evolution, study suggests

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      If we could rewind the tape of species evolution around the world and play it forward over hundreds of millions of years to the present day, we would see biodiversity clustering around regions of tectonic turmoil. Tectonically active regions such as the Himalayan and Andean mountains are especially rich in flora and fauna due to their shifting landscapes, which act to divide and diversify species over time.

      But biodiversity can also flourish in some geologically quieter regions, where tectonics hasn’t shaken up the land for millennia. The Appalachian Mountains are a prime example: The range has not seen much tectonic activity in hundreds of millions of years, and yet the region is a notable hotspot of freshwater biodiversity.

      Now, an MIT study identifies a geological process that may shape the diversity of species in tectonically inactive regions. In a paper appearing today in Science, the researchers report that river erosion can be a driver of biodiversity in these older, quieter environments.

      They make their case in the southern Appalachians, and specifically the Tennessee River Basin, a region known for its huge diversity of freshwater fishes. The team found that as rivers eroded through different rock types in the region, the changing landscape pushed a species of fish known as the greenfin darter into different tributaries of the river network. Over time, these separated populations developed into their own distinct lineages.

      The team speculates that erosion likely drove the greenfin darter to diversify. Although the separated populations appear outwardly similar, with the greenfin darter’s characteristic green-tinged fins, they differ substantially in their genetic makeup. For now, the separated populations are classified as one single species. 

      “Give this process of erosion more time, and I think these separate lineages will become different species,” says Maya Stokes PhD ’21, who carried out part of the work as a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

      The greenfin darter may not be the only species to diversify as a consequence of river erosion. The researchers suspect that erosion may have driven many other species to diversify throughout the basin, and possibly other tectonically inactive regions around the world.

      “If we can understand the geologic factors that contribute to biodiversity, we can do a better job of conserving it,” says Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric, and Planetary Sciences at MIT.

      The study’s co-authors include collaborators at Yale University, Colorado State University, the University of Tennessee, the University of Massachusetts at Amherst, and the Tennessee Valley Authority (TVA). Stokes is currently an assistant professor at Florida State University.

      Fish in trees

      The new study grew out of Stokes’ PhD work at MIT, where she and Perron were exploring connections between geomorphology (the study of how landscapes evolve) and biology. They came across work at Yale by Thomas Near, who studies lineages of North American freshwater fishes. Near uses DNA sequence data collected from freshwater fishes across various regions of North America to show how and when certain species evolved and diverged in relation to each other.

      Near brought a curious observation to the team: a habitat distribution map of the greenfin darter showing that the fish was found in the Tennessee River Basin — but only in the southern half. What’s more, Near had mitochondrial DNA sequence data showing that the fish’s populations appeared to be different in their genetic makeup depending on the tributary in which they were found.

      To investigate the reasons for this pattern, Stokes gathered greenfin darter tissue samples from Near’s extensive collection at Yale, as well as from the field with help from TVA colleagues. She then analyzed DNA sequences from across the entire genome, and compared the genes of each individual fish to every other fish in the dataset. The team then created a phylogenetic tree of the greenfin darter, based on the genetic similarity between fish.

      From this tree, they observed that fish within a tributary were more related to each other than to fish in other tributaries. What’s more, fish within neighboring tributaries were more similar to each other than fish from more distant tributaries.

      “Our question was, could there have been a geological mechanism that, over time, took this single species, and splintered it into different, genetically distinct groups?” Perron says.

      A changing landscape

      Stokes and Perron started to observe a “tight correlation” between greenfin darter habitats and the type of rock where they are found. In particular, much of the southern half of the Tennessee River Basin, where the species abounds, is made of metamorphic rock, whereas the northern half consists of sedimentary rock, where the fish are not found.

      They also observed that the rivers running through metamorphic rock are steeper and more narrow, which generally creates more turbulence, a characteristic greenfin darters seem to prefer. The team wondered: Could the distribution of greenfin darter habitat have been shaped by a changing landscape of rock type, as rivers eroded into the land over time?

      To check this idea, the researchers developed a model to simulate how a landscape evolves as rivers erode through various rock types. They fed the model information about the rock types in the Tennessee River Basin today, then ran the simulation back to see how the same region may have looked millions of years ago, when more metamorphic rock was exposed.

      They then ran the model forward and observed how the exposure of metamorphic rock shrank over time. They took special note of where and when connections between tributaries crossed into non-metamorphic rock, blocking fish from passing between those tributaries. They drew up a simple timeline of these blocking events and compared this to the phylogenetic tree of diverging greenfin darters. The two were remarkably similar: The fish seemed to form separate lineages in the same order as when their respective tributaries became separated from the others.

      “It means it’s plausible that erosion through different rock layers caused isolation between different populations of the greenfin darter and caused lineages to diversify,” Stokes says.

      “This study is highly compelling because it reveals a much more subtle but powerful mechanism for speciation in passive margins,” says Josh Roering, professor of Earth sciences at the University of Oregon, who was not involved in the study. “Stokes and Perron have revealed some of the intimate connections between aquatic species and geology that may be much more common than we realize.”

      This research was supported, in part, by the mTerra Catalyst Fund and the U.S. National Science Foundation through the AGeS Geochronology Program and the Graduate Research Fellowship Program. While at MIT, Stokes received support through the Martin Fellowship for Sustainability and the Hugh Hampton Young Fellowship. More

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      in Energy

      Understanding boiling to help the nuclear industry and space missions

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      To launch extended missions in space, the National Aeronautics and Space Administration (NASA) is borrowing a page from the nuclear engineering industry: It is trying to understand how boiling works.

      Planning for long-term missions has NASA researching ways of packing the least amount of cryogenic fuel possible for efficient liftoff. One potential solution is to refuel the rocket in space using fuel depots placed in low Earth orbits. This way, the spacecraft can carry the lightest fuel load — enough to reach the low Earth orbit to refuel as necessary and complete the mission. But refueling in space requires a thorough knowledge of cryogenic fuels.

      “We [need to understand] how boiling of cryogens behaves in microgravity conditions [encountered in space],” says Florian Chavagnat, a sixth-year doctoral candidate in the Department of Nuclear Science and Engineering (NSE). After all, understanding how cryogens boil in space is critical to NASA’s fuel management strategy. The vast majority of studies on boiling evaluate fluids that boil at high temperatures, which doesn’t necessarily apply to cryogens. Under the advisement of Matteo Bucci and Emilio Baglietto, Chavagnat is working on NASA-sponsored research about cryogens and the way the lack of buoyancy in space affects boiling.

      A childhood spent tinkering

      A deep understanding of engineering and physical phenomena is exactly what Chavagnat developed growing up in Boussy-Saint-Antoine, a suburb of Paris, with parents who worked for SNCF, the national state-owned rail company. Chavagnat remembers discussing the working of trains and motors with his engineer dad and building a variety of balsa-wood models. One of his memorable projects was a sailboat propelled by a motor from an electric toothbrush.

      By the time he was a teenager, Chavagnat received a metal lathe as a gift. His tinkering became an obsession; a compressed air engine was a favorite project. Soon his parents’ small shed, meant for gardening, became a factory, Chavagnat recalls, laughing.

      A lifelong love of math and physics propelled a path to the National Institute of Applied Science in Rouen, Normandy, where Chavagnat studied energetics and propulsion as part of a five-year engineering program. In his final year, Chavagnat studied atomic engineering from INSTN Paris-Saclay, part of the esteemed French Alternative Energies and Atomic Energy Commission (CEA).

      The final year of studies at CEA required a six-month-long internship, which traditionally sets the course for a job. Chavagnat decided to take a chance and apply for an internship at MIT NSE instead, knowing his future course might be uncertain. “I didn’t take a lot of risk in my life, but this one was a big risk,” Chavagnat says. The gamble paid off: Chavagnat won the internship with Charles Forsberg, which paved the way for his admission as a doctoral student. “I selected MIT because it has always been my dream school,” Chavagnat says. He also enjoyed the idea of challenging himself to improve his English-speaking skills.

      A love of physics and heat transfer

      Chavagnat loves physics — “if I can study any problem in physics, I’d be happy” he says — which led him to working on heat transfer, more specifically on boiling heat transfer. His early doctoral research focused on transient boiling in nuclear reactors, part of which has been published in the International Journal of Heat and Mass Transfer.

      Chavagnat’s research targets a specific kind of nuclear reactor called a material test reactor (MTR). Nuclear scientists use MTRs to understand how materials used in plant operations might behave under long-term use. Densely packed nuclear fuel, running at high power, simulates long-term effects using a very intense neutron flux.

      To prevent failure, operators limit reactor temperature by flowing very cold water at high velocity. When reactor heat power increases uncontrollably, the piped water begins to boil. Boiling works to prevent meltdown by altering neutron moderation and extracting heat from the fuel. “[Unfortunately], that only works until you reach a certain heat flux at the fuel cladding, after which the efficiency completely drops,” Chavagnat says. Once the critical heat flux is reached, water vapor starts to blanket and insulate the fuel elements, leading to rapidly rising cladding temperatures and potential burnout.

      The key is to figure out the behavior of maximum boiling heat flux under routine MTR conditions — cold water, high flow velocity, and narrow spacing between the fuel elements.

      Study of cryogenic boiling

      Boiling continues to occupy center stage as Chavagnat pursues the question for NASA. Cryogens boil at very low temperatures, so the question of how to prevent fuel loss from routine space-based operations is an important one to answer.

      Chavagnat is studying how boiling would behave under reduced or absent buoyancy, which are the conditions cryogenic rocket fuel will encounter in space.

      To reproduce space-like conditions on Earth, buoyancy can be modified without going to space. Chavagnat is manipulating the inclination of the boiling surface — placing it upside down is an example — such that buoyancy does not do what it usually does: help bubbles break away from the surface. He is also performing boiling experiments in parabolic flights to simulate microgravity, similar to what is experienced aboard the International Space Station.

      Chavagnat designed and built equipment which can perform both methods with minimum changes. “We observed nitrogen boiling on our surface by imaging it using two high-speed video cameras,” he says. The experiment was approved to go on board the parabolic flights operated by Zero-G, a company that operates weightless flights. The team successfully completed four parabolic flights in 2022.

      “Flying an experiment aboard an aircraft and operating it in microgravity is an incredible experience, but is challenging,” Chavagnat says, “Knowing the details the experiment is a must, but other skills are quite useful — in particular, working as a team, being able to manage high stress levels, and being able to work while being motion-sick.” Another challenge is that the majority of issues cannot be fixed once aboard, as aircraft pilots perform the parabola (each lasting 17 seconds) almost back-to-back.

      Throughout his research at MIT, Chavagnat has been captivated by how complex a simple phenomenon like boiling can truly be. “In your childhood, you have a certain idea of how boiling looks, relatively slow bubbles that you can see with the naked eye,” he says, “but you don’t realize the complexity until you see it with your own eyes.”

      In his infrequent spare time, Chavagnat plays soccer with the NSE’s team, the Atom Smashers. The group meets only five times a semester so it’s a low-key commitment, says Chavagnat who spends most of his time at the lab. “I am doing mostly experiments at MIT; it turns out the skills I learned in my shed when I was 15 are actually quite useful here,” he laughs. More

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      in Energy

      Six ways MIT is taking action on climate

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      From reuse and recycling to new carbon markets, events during Earth Month at MIT spanned an astonishing range of ideas and approaches to tackling the climate crisis. The MIT Climate Nucleus offered funding to departments and student organizations to develop programming that would showcase the countless initiatives underway to make a better world.

      Here are six — just six of many — ways the MIT community is making a difference on climate right now.

      1. Exchanging knowledge with policymakers to meet local, regional, and global challenges

      Creating solutions begins with understanding the problem.

      Speaking during the annual Earth Day Colloquium of the MIT Energy Initiative (MITEI) about the practical challenges of implementing wind-power projects, for instance, Massachusetts State Senator Michael J. Barrett offered a sobering assessment.

      The senate chair of the Joint Committee on Telecommunications, Utilities, and Energy, Barrett reported that while the coast of Massachusetts provides a conducive site for offshore wind, economic forces have knocked a major offshore wind installation project off track. The combination of the pandemic and global geopolitical instability has led to such great supply chain disruptions and rising commodity costs that a project considered necessary for the state to meet its near-term climate goals now faces delays, he said.

      Like others at MIT, MITEI researchers keep their work grounded in the real-world constraints and possibilities for decarbonization, engaging with policymakers and industry to understand the on-the-ground challenges to technological and policy-based solutions and highlight the opportunities for greatest impact.

      2. Developing new ways to prevent, mitigate, and adapt to the effects of climate change

      An estimated 20 percent of MIT faculty work on some aspect of the climate crisis, an enormous research effort distributed throughout the departments, labs, centers, and institutes.

      About a dozen such projects were on display at a poster session coordinated by the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS), Environmental Solutions Initiative (ESI), and MITEI.

      Students and postdocs presented innovations including:

      Graduate student Alexa Reese Canaan describes her research on household energy consumption to Massachusetts State Senator Michael J. Barrett, chair of the Joint Committee on Telecommunications, Utilities, and Energy.

      Photo: Caitlin Cunningham

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      3. Preparing students to meet the challenges of a climate-changed world

      Faculty and staff from more than 30 institutions of higher education convened at the MIT Symposium on Advancing Climate Education to exchange best practices and innovations in teaching and learning. Speakers and participants considered paths to structural change in higher education, the imperative to place equity and justice at the center of new educational approaches, and what it means to “educate the whole student” so that graduates are prepared to live and thrive in a world marked by global environmental and economic disruption.

      Later in April, MIT faculty voted to approve the creation of a new joint degree program in climate system science and engineering.

      4. Offering climate curricula to K-12 teachers

      At a daylong conference on climate education for K-12 schools, the attendees were not just science teachers. Close to 50 teachers of arts, literature, history, math, mental health, English language, world languages, and even carpentry were all hungry for materials and approaches to integrate into their curricula. They were joined by another 50 high school students, ready to test out the workshops and content developed by MIT Climate Action Through Education (CATE), which are already being piloted in at least a dozen schools.

      The CATE initiative is led by Christopher Knittel, the George P. Shultz Professor of Energy Economics at the MIT Sloan School of Management, deputy director for policy at MITEI, and faculty director of the MIT Center for Energy and Environmental Policy Research. The K-12 Climate Action and Education Conference was hosted as a collaboration with the Massachusetts Teachers Association Climate Action Network and Earth Day Boston.

      “We will be honest about the threats posed by climate change, but also give students a sense of agency that they can do something about this,” Knittel told MITEI Energy Futures earlier this spring. “And for the many teachers — especially non-science teachers — starved for knowledge and background material, CATE offers resources to give them confidence to implement our curriculum.”

      High school students and K-12 teachers participated in a workshop on “Exploring a Green City,” part of the Climate Action and Education Conference on April 1.

      Photo: Tony Rinaldo

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      5. Guiding our communities in making sense of the coming changes

      The arts and humanities, vital in their own right, are also central to the sharing of scientific knowledge and its integration into culture, behavior, and decision-making. A message well-delivered can reach new audiences and prompt reflection and reckoning on ethics and values, identity, and optimism.

      The Climate Machine, part of ESI’s Arts and Climate program, produced an evening art installation on campus featuring dynamic, large-scale projections onto the façade of MIT’s new music building and a musical performance by electronic duo Warung. Passers-by were invited to take a Climate Identity Quiz, with the responses reflected in the visuals. Another exhibit displayed the results of a workshop in which attendees had used an artificial intelligence art tool to imagine the future of their hometowns, while another highlighted native Massachusetts wildlife.

      The Climate Machine is an MIT research project undertaken in collaboration with record label Anjunabeats. The collaborative team imagines interactive experiences centered on sustainability that could be deployed at musical events and festivals to inspire climate action.

      Dillon Ames (left) and Aaron Hopkins, known as the duo Warung, perform a live set during the Climate Machine art installation.

      Photo: Caitlin Cunningham

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      6. Empowering students to seize this unique policy moment

      ESI’s TILclimate Podcast, which breaks down important climate topics for general listeners, held a live taping at the MIT Museum and offered an explainer on three recent, major pieces of federal legislation: the Inflation Reduction Act of 2022, the Bipartisan Infrastructure Bill of 2021, and the CHIPS and Science Act of 2022.

      The combination of funding and financial incentives for energy- and climate-related projects, along with reinvestment in industrial infrastructure, create “a real moment and an opportunity,” said special guest Elisabeth Reynolds, speaking with host Laur Hesse Fisher. Reynolds was a member of the National Economic Council from 2021 to 2022, serving as special assistant to the president for manufacturing and economic development; after leaving the White House, Reynolds returned to MIT, where she is a lecturer in MIT’s Department of Urban Studies and Planning.

      For students, the opportunities to engage have never been better, Reynolds urged: “There is so much need. … Find a way to contribute, and find a way to help us make this transformation.”

      “What we’re embarking on now, you just can’t overstate the significance of it,” she said.

      For more information on how MIT is advancing climate action across education; research and innovation; policy; economic, social, and environmental justice; public and global engagement; sustainable campus operations; and more, visit Fast Forward: MIT’s Climate Action Plan for the Decade. The actions described in the plan aim to accelerate the global transition to net-zero carbon emissions, and to “educate and empower the next generation.” More

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      in Environment

      3 Questions: Can disused croplands help mitigate climate change?

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      As the world struggles to meet internationally agreed targets for reducing greenhouse gas emissions, methods of removing carbon dioxide such as reforestation of cleared areas have become an increasingly important strategy. But little attention has been paid to the potential for abandoned or marginal croplands to be restored to natural vegetation as an additional carbon sink, say MIT assistant professor of civil and environmental engineering César Terrer, recent visiting MIT doctoral student Stephen M. Bell, and six others, in a recent open-access paper in the journal Nature Communications. Here, Terrer and Bell explain the potential use of these “post-agricultural” lands to help in the fight against damaging climate change.

      Q: How significant is the potential of unused agricultural lands as a carbon sink to help mitigate climate change?

      Bell: We know of these huge instances of land abandonment and post-agricultural succession throughout history, like following the collapse of major cities from ancient Mesopotamia to the Mayans. And when the Europeans arrived in the Americas in the 15th century, so many people died and so much forest grew back on abandoned farmland that it helped cool the entire planet and was potentially a driver of the coldest part of the so-called “Little Ice Age” period.

      Today, we have abandoned farmland all over the Mediterranean region, where I did my PhD field work. As young people left rural areas for the cities throughout the 20th century, farmers couldn’t pass on their land to anyone, and the land succeeded back into shrub lands and forests. The biggest recent example of abandonment is for sure the collapse of the Soviet Union, where an estimated 60 million hectares of forest regrew when support for collective farming stopped, resulting in one of the largest carbon sinks ever attributed to a single event.

      So, when we look back at the past, we know there’s potential. Of course, these are huge events, and no one is proposing to replicate anything like that. We need to use land for multiple purposes, but looking back at these big examples, we know there is potential for abandoned or restored agricultural land to be carbon sinks. And so that tells us to dig deeper into this question and get a better idea of realistic scenarios, a better understanding of the climate change mitigation potential of agricultural cessation in the most strategic places.

      Terrer: More than 115 billion tons of carbon have been lost from soils due to agricultural practices that disturb soil integrity — such as tilling, monoculture farming, removing crop residue, excessive use of fertilizers and pesticides, and over-grazing. To put this into perspective, the amount of carbon lost is equivalent to the total CO2 emissions ever produced in the United States.

      Our current research synthesizes field data from thousands of experiments, aiming to understand the factors that influence soil carbon accrual in abandoned croplands transitioning back to forests or natural grasslands. We’re working to quantify the potential for carbon sequestration in these soils over 30-, 50-, and 100-year time frames and mapping the areas with the greatest potential for carbon storage. This includes both increases in soil carbon and in vegetation biomass.

      Q: What are some of the key uncertainties in evaluating this potential for unused cropland to serve as a carbon sink, and how could those uncertainties be addressed?

      Bell: We use this word uncertainties in two ways. Specifically, the longevity of potential recarbonization, and the intensity of the potential recarbonization. Those are two factors, two aspects that we need to quantify to reduce our uncertainty.

      So, how long will the land recarbonize, regardless of the intensity? If the carbon level is going up, that’s good. If there’s more carbon increasing in the soil, we know that it came from somewhere, it came from the atmosphere. But how long does that happen? We know soil can get saturated. It can reach its carbon capacity limit, it won’t continue to increase the carbon stock, and the recarbonization curve will flatten out. When does that happen? Is it after a hundred years? Is it after 20 years?

      But the world’s soils are very diverse and complex, so what might be true in one place is not true in another place. It may take a longer time to reach saturation for more fertile soils in the Midwest U.S. than less fertile soils in the Southwest, for example. Alternatively, sometimes soils in drier areas like in the Southwest may never reach true saturation if they are degraded and have stalled recovery following abandonment.

      The second uncertainty is intensity: How high on the y-axis on the chart of recarbonization does saturation occur? With the analogy comparing U.S. soils, you might have a relatively huge carbon increase on an abandoned farm in the Southwest, but because the soil is not very carbon-rich it’s not a large increase in absolute terms. In the Midwest, there might only be a small relative increase, but that increase could be much more in total than in the Southwest. These are just nuances to keep in mind as we look at this at the global scale.

      These nuances are essentially uncertainties. Soil carbon responses to agricultural land abandonment is complicated, and unfortunately it hasn’t been studied in much detail so far. We need to reduce those uncertainties to get a better understanding of the recarbonization potential. This is easier said than done because not only do we have these temporal data uncertainties, but we also have spatial uncertainties. We don’t have very good maps of past and present post-agricultural landscapes.

      Q: Can this potential use of post-agricultural lands be implemented without putting global food supplies at risk? How can these needs be balanced?

      Terrer: As to whether utilizing post-agricultural lands for carbon sequestration can be implemented without jeopardizing global food supplies, and how to balance these needs, our recent research provides valuable insights.

      The challenge, of course, lies in balancing cropland restoration for climate mitigation with food security for a growing global population. Abandoned croplands represent an opportunity for carbon sequestration without impacting active agricultural lands. However, the available area of abandoned croplands is insufficient to make a substantial impact on climate mitigation on its own.

      Thus, our proposal also emphasizes the importance of closing yield gaps, which involves increasing crop production per hectare to its theoretical limits. This would enable us to maintain or even increase global crop yields using only a fraction of the currently cultivated area, allowing the remaining land to be dedicated to climate mitigation efforts. By pursuing this strategy, we estimate that over half of the amount of soil carbon lost so far due to agriculture could be recovered, while ensuring food security for the world’s population. More

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      in Environment

      J-WAFS announces 2023 seed grant recipients

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      Today, the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) announced its ninth round of seed grants to support innovative research projects at MIT. The grants are designed to fund research efforts that tackle challenges related to water and food for human use, with the ultimate goal of creating meaningful impact as the world population continues to grow and the planet undergoes significant climate and environmental changes.Ten new projects led by 15 researchers from seven different departments will be supported this year. The projects address a range of challenges by employing advanced materials, technology innovations, and new approaches to resource management. The new projects aim to remove harmful chemicals from water sources, develop monitoring and other systems to help manage various aquaculture industries, optimize water purification materials, and more.“The seed grant program is J-WAFS’ flagship grant initiative,” says J-WAFS executive director Renee J. Robins. “The funding is intended to spur groundbreaking MIT research addressing complex issues that are challenging our water and food systems. The 10 projects selected this year show great promise, and we look forward to the progress and accomplishments these talented researchers will make,” she adds.The 2023 J-WAFS seed grant researchers and their projects are:Sara Beery, an assistant professor in the Department of Electrical Engineering and Computer Science (EECS), is building the first completely automated system to estimate the size of salmon populations in the Pacific Northwest (PNW).Salmon are a keystone species in the PNW, feeding human populations for the last 7,500 years at least. However, overfishing, habitat loss, and climate change threaten extinction of salmon populations across the region. Accurate salmon counts during their seasonal migration to their natal river to spawn are essential for fisheries’ regulation and management but are limited by human capacity. Fish population monitoring is a widespread challenge in the United States and worldwide. Beery and her team are working to build a system that will provide a detailed picture of the state of salmon populations in unprecedented, spatial, and temporal resolution by combining sonar sensors and computer vision and machine learning (CVML) techniques. The sonar will capture individual fish as they swim upstream and CVML will train accurate algorithms to interpret the sonar video for detecting, tracking, and counting fish automatically while adapting to changing river conditions and fish densities.Another aquaculture project is being led by Michael Triantafyllou, the Henry L. and Grace Doherty Professor in Ocean Science and Engineering in the Department of Mechanical Engineering, and Robert Vincent, the assistant director at MIT’s Sea Grant Program. They are working with Otto Cordero, an associate professor in the Department of Civil and Environmental Engineering, to control harmful bacteria blooms in aquaculture algae feed production.

      Aquaculture in the United States represents a $1.5 billion industry annually and helps support 1.7 million jobs, yet many American hatcheries are not able to keep up with demand. One barrier to aquaculture production is the high degree of variability in survival rates, most likely caused by a poorly controlled microbiome that leads to bacterial infections and sub-optimal feed efficiency. Triantafyllou, Vincent, and Cordero plan to monitor the microbiome composition of a shellfish hatchery in order to identify possible causing agents of mortality, as well as beneficial microbes. They hope to pair microbe data with detail phenotypic information about the animal population to generate rapid diagnostic tests and explore the potential for microbiome therapies to protect larvae and prevent future outbreaks. The researchers plan to transfer their findings and technology to the local and regional aquaculture community to ensure healthy aquaculture production that will support the expansion of the U.S. aquaculture industry.

      David Des Marais is the Cecil and Ida Green Career Development Professor in the Department of Civil and Environmental Engineering. His 2023 J-WAFS project seeks to understand plant growth responses to elevated carbon dioxide (CO2) in the atmosphere, in the hopes of identifying breeding strategies that maximize crop yield under future CO2 scenarios.Today’s crop plants experience higher atmospheric CO2 than 20 or 30 years ago. Crops such as wheat, oat, barley, and rice typically increase their growth rate and biomass when grown at experimentally elevated atmospheric CO2. This is known as the so-called “CO2 fertilization effect.” However, not all plant species respond to rising atmospheric CO2 with increased growth, and for the ones that do, increased growth doesn’t necessarily correspond to increased crop yield. Using specially built plant growth chambers that can control the concentration of CO2, Des Marais will explore how CO2 availability impacts the development of tillers (branches) in the grass species Brachypodium. He will study how gene expression controls tiller development, and whether this is affected by the growing environment. The tillering response refers to how many branches a plant produces, which sets a limit on how much grain it can yield. Therefore, optimizing the tillering response to elevated CO2 could greatly increase yield. Des Marais will also look at the complete genome sequence of Brachypodium, wheat, oat, and barley to help identify genes relevant for branch growth.Darcy McRose, an assistant professor in the Department of Civil and Environmental Engineering, is researching whether a combination of plant metabolites and soil bacteria can be used to make mineral-associated phosphorus more bioavailable.The nutrient phosphorus is essential for agricultural plant growth, but when added as a fertilizer, phosphorus sticks to the surface of soil minerals, decreasing bioavailability, limiting plant growth, and accumulating residual phosphorus. Heavily fertilized agricultural soils often harbor large reservoirs of this type of mineral-associated “legacy” phosphorus. Redox transformations are one chemical process that can liberate mineral-associated phosphorus. However, this needs to be carefully controlled, as overly mobile phosphorus can lead to runoff and pollution of natural waters. Ideally, phosphorus would be made bioavailable when plants need it and immobile when they don’t. Many plants make small metabolites called coumarins that might be able to solubilize mineral-adsorbed phosphorus and be activated and inactivated under different conditions. McRose will use laboratory experiments to determine whether a combination of plant metabolites and soil bacteria can be used as a highly efficient and tunable system for phosphorus solubilization. She also aims to develop an imaging platform to investigate exchanges of phosphorus between plants and soil microbes.Many of the 2023 seed grants will support innovative technologies to monitor, quantify, and remediate various kinds of pollutants found in water. Two of the new projects address the problem of per- and polyfluoroalkyl substances (PFAS), human-made chemicals that have recently emerged as a global health threat. Known as “forever chemicals,” PFAS are used in many manufacturing processes. These chemicals are known to cause significant health issues including cancer, and they have become pervasive in soil, dust, air, groundwater, and drinking water. Unfortunately, the physical and chemical properties of PFAS render them difficult to detect and remove.Aristide Gumyusenge, the Merton C. Assistant Professor of Materials Science and Engineering, is using metal-organic frameworks for low-cost sensing and capture of PFAS. Most metal-organic frameworks (MOFs) are synthesized as particles, which complicates their high accuracy sensing performance due to defects such as intergranular boundaries. Thin, film-based electronic devices could enable the use of MOFs for many applications, especially chemical sensing. Gumyusenge’s project aims to design test kits based on two-dimensional conductive MOF films for detecting PFAS in drinking water. In early demonstrations, Gumyusenge and his team showed that these MOF films can sense PFAS at low concentrations. They will continue to iterate using a computation-guided approach to tune sensitivity and selectivity of the kits with the goal of deploying them in real-world scenarios.Carlos Portela, the Brit (1961) and Alex (1949) d’Arbeloff Career Development Professor in the Department of Mechanical Engineering, and Ariel Furst, the Cook Career Development Professor in the Department of Chemical Engineering, are building novel architected materials to act as filters for the removal of PFAS from water. Portela and Furst will design and fabricate nanoscale materials that use activated carbon and porous polymers to create a physical adsorption system. They will engineer the materials to have tunable porosities and morphologies that can maximize interactions between contaminated water and functionalized surfaces, while providing a mechanically robust system.Rohit Karnik is a Tata Professor and interim co-department head of the Department of Mechanical Engineering. He is working on another technology, his based on microbead sensors, to rapidly measure and monitor trace contaminants in water.Water pollution from both biological and chemical contaminants contributes to an estimated 1.36 million deaths annually. Chemical contaminants include pesticides and herbicides, heavy metals like lead, and compounds used in manufacturing. These emerging contaminants can be found throughout the environment, including in water supplies. The Environmental Protection Agency (EPA) in the United States sets recommended water quality standards, but states are responsible for developing their own monitoring criteria and systems, which must be approved by the EPA every three years. However, the availability of data on regulated chemicals and on candidate pollutants is limited by current testing methods that are either insensitive or expensive and laboratory-based, requiring trained scientists and technicians. Karnik’s project proposes a simple, self-contained, portable system for monitoring trace and emerging pollutants in water, making it suitable for field studies. The concept is based on multiplexed microbead-based sensors that use thermal or gravitational actuation to generate a signal. His proposed sandwich assay, a testing format that is appealing for environmental sensing, will enable both single-use and continuous monitoring. The hope is that the bead-based assays will increase the ease and reach of detecting and quantifying trace contaminants in water for both personal and industrial scale applications.Alexander Radosevich, a professor in the Department of Chemistry, and Timothy Swager, the John D. MacArthur Professor of Chemistry, are teaming up to create rapid, cost-effective, and reliable techniques for on-site arsenic detection in water.Arsenic contamination of groundwater is a problem that affects as many as 500 million people worldwide. Arsenic poisoning can lead to a range of severe health problems from cancer to cardiovascular and neurological impacts. Both the EPA and the World Health Organization have established that 10 parts per billion is a practical threshold for arsenic in drinking water, but measuring arsenic in water at such low levels is challenging, especially in resource-limited environments where access to sensitive laboratory equipment may not be readily accessible. Radosevich and Swager plan to develop reaction-based chemical sensors that bind and extract electrons from aqueous arsenic. In this way, they will exploit the inherent reactivity of aqueous arsenic to selectively detect and quantify it. This work will establish the chemical basis for a new method of detecting trace arsenic in drinking water.Rajeev Ram is a professor in the Department of Electrical Engineering and Computer Science. His J-WAFS research will advance a robust technology for monitoring nitrogen-containing pollutants, which threaten over 15,000 bodies of water in the United States alone.Nitrogen in the form of nitrate, nitrite, ammonia, and urea can run off from agricultural fertilizer and lead to harmful algal blooms that jeopardize human health. Unfortunately, monitoring these contaminants in the environment is challenging, as sensors are difficult to maintain and expensive to deploy. Ram and his students will work to establish limits of detection for nitrate, nitrite, ammonia, and urea in environmental, industrial, and agricultural samples using swept-source Raman spectroscopy. Swept-source Raman spectroscopy is a method of detecting the presence of a chemical by using a tunable, single mode laser that illuminates a sample. This method does not require costly, high-power lasers or a spectrometer. Ram will then develop and demonstrate a portable system that is capable of achieving chemical specificity in complex, natural environments. Data generated by such a system should help regulate polluters and guide remediation.Kripa Varanasi, a professor in the Department of Mechanical Engineering, and Angela Belcher, the James Mason Crafts Professor and head of the Department of Biological Engineering, will join forces to develop an affordable water disinfection technology that selectively identifies, adsorbs, and kills “superbugs” in domestic and industrial wastewater.Recent research predicts that antibiotic-resistance bacteria (superbugs) will result in $100 trillion in health care expenses and 10 million deaths annually by 2050. The prevalence of superbugs in our water systems has increased due to corroded pipes, contamination, and climate change. Current drinking water disinfection technologies are designed to kill all types of bacteria before human consumption. However, for certain domestic and industrial applications there is a need to protect the good bacteria required for ecological processes that contribute to soil and plant health. Varanasi and Belcher will combine material, biological, process, and system engineering principles to design a sponge-based water disinfection technology that can identify and destroy harmful bacteria while leaving the good bacteria unharmed. By modifying the sponge surface with specialized nanomaterials, their approach will be able to kill superbugs faster and more efficiently. The sponge filters can be deployed under very low pressure, making them an affordable technology, especially in resource-constrained communities.In addition to the 10 seed grant projects, J-WAFS will also fund a research initiative led by Greg Sixt. Sixt is the research manager for climate and food systems at J-WAFS, and the director of the J-WAFS-led Food and Climate Systems Transformation (FACT) Alliance. His project focuses on the Lake Victoria Basin (LVB) of East Africa. The second-largest freshwater lake in the world, Lake Victoria straddles three countries (Uganda, Tanzania, and Kenya) and has a catchment area that encompasses two more (Rwanda and Burundi). Sixt will collaborate with Michael Hauser of the University of Natural Resources and Life Sciences, Vienna, and Paul Kariuki, of the Lake Victoria Basin Commission.The group will study how to adapt food systems to climate change in the Lake Victoria Basin. The basin is facing a range of climate threats that could significantly impact livelihoods and food systems in the expansive region. For example, extreme weather events like droughts and floods are negatively affecting agricultural production and freshwater resources. Across the LVB, current approaches to land and water management are unsustainable and threaten future food and water security. The Lake Victoria Basin Commission (LVBC), a specialized institution of the East African Community, wants to play a more vital role in coordinating transboundary land and water management to support transitions toward more resilient, sustainable, and equitable food systems. The primary goal of this research will be to support the LVBC’s transboundary land and water management efforts, specifically as they relate to sustainability and climate change adaptation in food systems. The research team will work with key stakeholders in Kenya, Uganda, and Tanzania to identify specific capacity needs to facilitate land and water management transitions. The two-year project will produce actionable recommendations to the LVBC. More