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      in Environment

      3Q: Why Europe is so vulnerable to heat waves

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      This year saw high-temperature records shattered across much of Europe, as crops withered in the fields due to widespread drought. Is this a harbinger of things to come as the Earth’s climate steadily warms up?

      Elfatih Eltahir, MIT professor of civil and environmental engineering and H. M. King Bhumibol Professor of Hydrology and Climate, and former doctoral student Alexandre Tuel PhD ’20 recently published a piece in the Bulletin of the Atomic Scientists describing how their research helps explain this anomalous European weather. The findings are based in part on analyses described in their book “Future Climate of the Mediterranean and Europe,” published earlier this year. MIT News asked the two authors to describe the dynamics behind these extreme weather events.

      Q: Was the European heat wave this summer anticipated based on existing climate models?

      Eltahir: Climate models project increasingly dry summers over Europe. This is especially true for the second half of the 21st century, and for southern Europe. Extreme dryness is often associated with hot conditions and heat waves, since any reduction in evaporation heats the soil and the air above it. In general, models agree in making such projections about European summers. However, understanding the physical mechanisms responsible for these projections is an active area of research.

      The same models that project dry summers over southern Europe also project dry winters over the neighboring Mediterranean Sea. In fact, the Mediterranean Sea stands out as one of the most significantly impacted regions — a literal “hot spot” — for winter droughts triggered by climate change. Again, until recently, the association between the projections of summer dryness over Europe and dry winters over the Mediterranean was not understood.

      In recent MIT doctoral research, carried out in the Department of Civil and Environmental Engineering, a hypothesis was developed to explain why the Mediterranean stands out as a hot spot for winter droughts under climate change. Further, the same theory offers a mechanistic understanding that connects the projections of dry summers over southern Europe and dry winters over the Mediterranean.

      What is exciting about the observed climate over Europe last summer is the fact that the observed drought started and developed with spatial and temporal patterns that are consistent with our proposed theory, and in particular the connection to the dry conditions observed over the Mediterranean during the previous winter.

      Q: What is it about the area around the Mediterranean basin that produces such unusual weather extremes?

      Eltahir: Multiple factors come together to cause extreme heat waves such as the one that Europe has experienced this summer, as well as previously, in 2003, 2015, 2018, 2019, and 2020. Among these, however, mutual influences between atmospheric dynamics and surface conditions, known as land-atmosphere feedbacks, seem to play a very important role.

      In the current climate, southern Europe is located in the transition zone between the dry subtropics (the Sahara Desert in North Africa) and the relatively wet midlatitudes (with a climate similar to that of the Pacific Northwest). High summertime temperatures tend to make the precipitation that falls to the ground evaporate quickly, and as a consequence soil moisture during summer is very dependent on springtime precipitation. A dry spring in Europe (such as the 2022 one) causes dry soils in late spring and early summer. This lack of surface water in turn limits surface evaporation during summer. Two important consequences follow: First, incoming radiative energy from the sun preferentially goes into increasing air temperature rather than evaporating water; and second, the inflow of water into air layers near the surface decreases, which makes the air drier and precipitation less likely. Combined, these two influences increase the likelihood of heat waves and droughts.

      Tuel: Through land-atmosphere feedbacks, dry springs provide a favorable environment for persistent warm and dry summers but are of course not enough to directly cause heat waves. A spark is required to ignite the fuel. In Europe and elsewhere, this spark is provided by large-scale atmospheric dynamics. If an anticyclone sets over an area with very dry soils, surface temperature can quickly shoot up as land-atmosphere feedbacks come into play, developing into a heat wave that can persist for weeks.

      The sensitivity to springtime precipitation makes southern Europe and the Mediterranean particularly prone to persistent summer heat waves. This will play an increasingly important role in the future, as spring precipitation is expected to decline, making scorching summers even more likely in this corner of the world. The decline in spring precipitation, which originates as an anomalously dry winter around the Mediterranean, is very robust across climate projections. Southern Europe and the Mediterranean really stand out from most other land areas, where precipitation will on average increase with global warming.

      In our work, we showed that this Mediterranean winter decline was driven by two independent factors: on the one hand, trends in the large-scale circulation, notably stationary atmospheric waves, and on the other hand, reduced warming of the Mediterranean Sea relative to the surrounding continents — a well-known feature of global warming. Both factors lead to increased surface air pressure and reduced precipitation over the Mediterranean and Southern Europe.

      Q: What can we expect over the coming decades in terms of the frequency and severity of these kinds of droughts, floods, and other extremes in European weather?

      Tuel: Climate models have long shown that the frequency and intensity of heat waves was bound to increase as the global climate warms, and Europe is no exception. The reason is simple: As the global temperature rises, the temperature distribution shifts toward higher values, and heat waves become more intense and more frequent. Southern Europe and the Mediterranean, however, will be hit particularly hard. The reason for this is related to the land-atmosphere feedbacks we just discussed. Winter precipitation over the Mediterranean and spring precipitation over southern Europe will decline significantly, which will lead to a decrease in early summer soil moisture over southern Europe and will push average summer temperatures even higher; the region will become a true climate change hot spot. In that sense, 2022 may really be a taste of the future. The succession of recent heat waves in Europe, however, suggests that things may be going faster than climate model projections imply. Decadal variability or badly understood trends in large-scale atmospheric dynamics may play a role here, though that is still debated. Another possibility is that climate models tend to underestimate the magnitude of land-atmosphere feedbacks and downplay the influence of dry soil moisture anomalies on summertime weather.

      Potential trends in floods are more difficult to assess because floods result from a multiplicity of factors, like extreme precipitation, soil moisture levels, or land cover. Extreme precipitation is generally expected to increase in most regions, but very high uncertainties remain, notably because extreme precipitation is highly dependent on atmospheric dynamics about which models do not always agree. What is almost certain is that with warming, the water content of the atmosphere increases (following a law of thermodynamics known as the Clausius-Clapeyron relationship). Thus, if the dynamics are favorable to precipitation, a lot more of it may fall in a warmer climate. Last year’s floods in Germany, for example, were triggered by unprecedented heavy rainfall which climate change made more likely. More

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      in Environment

      From bridges to DNA: civil engineering across disciplines

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      How is DNA like a bridge? This question is not a riddle or logic game, it is a concern of Johannes Kalliauer’s doctoral thesis.

      As a student at TU Wien in Austria, Kalliauer was faced with a monumental task: combining approaches from civil engineering and theoretical physics to better understand the forces that act on DNA.

      Kalliauer, now a postdoc at the MIT Concrete Sustainability Hub, says he modeled DNA as though it were a beam, using molecular dynamics principles to understand its structural properties.

      “The mechanics of very small objects, like DNA helices, and large ones, like bridges, are quite similar. Each may be understood in terms of Newtonian mechanics. Forces and moments act on each system, subjecting each to deformations like twisting, stretching, and warping,” says Kalliauer.

      As a 2020 article from TU Wien noted, Kalliauer observed a counterintuitive behavior when examining DNA at an atomic level. Unlike a typical spring which becomes less coiled as it is stretched, DNA was observed to become more wound as its length was increased. 

      In situations like these where conventional logic appears to break down, Kalliauer relies on the intuition he has gained as an engineer.

      “To understand this strange behavior in DNA, I turned to a fundamental approach: I examined what was the same about DNA and macroscopic structures and what was different. Civil engineers use methods and calculations which have been developed over centuries and which are very similar to the ones I employed for my thesis,” Kalliauer explains. 

      As Kalliauer continues, “Structural engineering is an incredibly versatile discipline. If you understand it, you can understand atomistic objects like DNA strands and very large ones like galaxies. As a researcher, I rely on it to help me bring new viewpoints to fields like biology. Other civil engineers can and should do the same.”

      Kalliauer, who grew up in a small town in Austria, has spent his life applying unconventional approaches like this across disciplines. “I grew up in a math family. While none of us were engineers, my parents instilled an appreciation for the discipline in me and my two older sisters.”

      After middle school, Kalliauer attended a technical school for civil engineering, where he discovered a fascination for mechanics. He also worked on a construction site to gain practical experience and see engineering applied in a real-world context.

      Kalliauer studied out of interest intensely, working upwards of 100 hours per week to better understand coursework in university. “I asked teachers and professors many questions, often challenging their ideas. Above everything else, I needed to understand things for myself. Doing well on exams was a secondary concern.”

      In university, he studied topics ranging from car crash testing to concrete hinges to biology. As a new member of the CSHub, he is studying how floods may be modeled with the statistical physics-based model provided by lattice density functional theory.

      In doing this, he builds on the work of past and present CSHub researchers like Elli Vartziotis and Katerina Boukin. 

      “It’s important to me that this research has a real impact in the world. I hope my approach to engineering can help researchers and stakeholders understand how floods propagate in urban contexts, so that we may make cities more resilient,” he says. More

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      in Energy

      A new method boosts wind farms’ energy output, without new equipment

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      Virtually all wind turbines, which produce more than 5 percent of the world’s electricity, are controlled as if they were individual, free-standing units. In fact, the vast majority are part of larger wind farm installations involving dozens or even hundreds of turbines, whose wakes can affect each other.

      Now, engineers at MIT and elsewhere have found that, with no need for any new investment in equipment, the energy output of such wind farm installations can be increased by modeling the wind flow of the entire collection of turbines and optimizing the control of individual units accordingly.

      The increase in energy output from a given installation may seem modest — it’s about 1.2 percent overall, and 3 percent for optimal wind speeds. But the algorithm can be deployed at any wind farm, and the number of wind farms is rapidly growing to meet accelerated climate goals. If that 1.2 percent energy increase were applied to all the world’s existing wind farms, it would be the equivalent of adding more than 3,600 new wind turbines, or enough to power about 3 million homes, and a total gain to power producers of almost a billion dollars per year, the researchers say. And all of this for essentially no cost.

      The research is published today in the journal Nature Energy, in a study led by MIT Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering Michael F. Howland.

      “Essentially all existing utility-scale turbines are controlled ‘greedily’ and independently,” says Howland. The term “greedily,” he explains, refers to the fact that they are controlled to maximize only their own power production, as if they were isolated units with no detrimental impact on neighboring turbines.

      But in the real world, turbines are deliberately spaced close together in wind farms to achieve economic benefits related to land use (on- or offshore) and to infrastructure such as access roads and transmission lines. This proximity means that turbines are often strongly affected by the turbulent wakes produced by others that are upwind from them — a factor that individual turbine-control systems do not currently take into account.

      “From a flow-physics standpoint, putting wind turbines close together in wind farms is often the worst thing you could do,” Howland says. “The ideal approach to maximize total energy production would be to put them as far apart as possible,” but that would increase the associated costs.

      That’s where the work of Howland and his collaborators comes in. They developed a new flow model which predicts the power production of each turbine in the farm depending on the incident winds in the atmosphere and the control strategy of each turbine. While based on flow-physics, the model learns from operational wind farm data to reduce predictive error and uncertainty. Without changing anything about the physical turbine locations and hardware systems of existing wind farms, they have used the physics-based, data-assisted modeling of the flow within the wind farm and the resulting power production of each turbine, given different wind conditions, to find the optimal orientation for each turbine at a given moment. This allows them to maximize the output from the whole farm, not just the individual turbines.

      Today, each turbine constantly senses the incoming wind direction and speed and uses its internal control software to adjust its yaw (vertical axis) angle position to align as closely as possible to the wind. But in the new system, for example, the team has found that by turning one turbine just slightly away from its own maximum output position — perhaps 20 degrees away from its individual peak output angle — the resulting increase in power output from one or more downwind units will more than make up for the slight reduction in output from the first unit. By using a centralized control system that takes all of these interactions into account, the collection of turbines was operated at power output levels that were as much as 32 percent higher under some conditions.

      In a months-long experiment in a real utility-scale wind farm in India, the predictive model was first validated by testing a wide range of yaw orientation strategies, most of which were intentionally suboptimal. By testing many control strategies, including suboptimal ones, in both the real farm and the model, the researchers could identify the true optimal strategy. Importantly, the model was able to predict the farm power production and the optimal control strategy for most wind conditions tested, giving confidence that the predictions of the model would track the true optimal operational strategy for the farm. This enables the use of the model to design the optimal control strategies for new wind conditions and new wind farms without needing to perform fresh calculations from scratch.

      Then, a second months-long experiment at the same farm, which implemented only the optimal control predictions from the model, proved that the algorithm’s real-world effects could match the overall energy improvements seen in simulations. Averaged over the entire test period, the system achieved a 1.2 percent increase in energy output at all wind speeds, and a 3 percent increase at speeds between 6 and 8 meters per second (about 13 to 18 miles per hour).

      While the test was run at one wind farm, the researchers say the model and cooperative control strategy can be implemented at any existing or future wind farm. Howland estimates that, translated to the world’s existing fleet of wind turbines, a 1.2 percent overall energy improvement would produce  more than 31 terawatt-hours of additional electricity per year, approximately equivalent to installing an extra 3,600 wind turbines at no cost. This would translate into some $950 million in extra revenue for the wind farm operators per year, he says.

      The amount of energy to be gained will vary widely from one wind farm to another, depending on an array of factors including the spacing of the units, the geometry of their arrangement, and the variations in wind patterns at that location over the course of a year. But in all cases, the model developed by this team can provide a clear prediction of exactly what the potential gains are for a given site, Howland says. “The optimal control strategy and the potential gain in energy will be different at every wind farm, which motivated us to develop a predictive wind farm model which can be used widely, for optimization across the wind energy fleet,” he adds.

      But the new system can potentially be adopted quickly and easily, he says. “We don’t require any additional hardware installation. We’re really just making a software change, and there’s a significant potential energy increase associated with it.” Even a 1 percent improvement, he points out, means that in a typical wind farm of about 100 units, operators could get the same output with one fewer turbine, thus saving the costs, usually millions of dollars, associated with purchasing, building, and installing that unit.

      Further, he notes, by reducing wake losses the algorithm could make it possible to place turbines more closely together within future wind farms, therefore increasing the power density of wind energy, saving on land (or sea) footprints. This power density increase and footprint reduction could help to achieve pressing greenhouse gas emission reduction goals, which call for a substantial expansion of wind energy deployment, both on and offshore.

      What’s more, he says, the biggest new area of wind farm development is offshore, and “the impact of wake losses is often much higher in offshore wind farms.” That means the impact of this new approach to controlling those wind farms could be significantly greater.

      The Howland Lab and the international team is continuing to refine the models further and working to improve the operational instructions they derive from the model, moving toward autonomous, cooperative control and striving for the greatest possible power output from a given set of conditions, Howland says.

      The research team includes Jesús Bas Quesada, Juan José Pena Martinez, and Felipe Palou Larrañaga of Siemens Gamesa Renewable Energy Innovation and Technology in Navarra, Spain; Neeraj Yadav and Jasvipul Chawla at ReNew Power Private Limited in Haryana, India; Varun Sivaram formerly at ReNew Power Private Limited in Haryana, India and presently at the Office of the U.S. Special Presidential Envoy for Climate, United States Department of State; and John Dabiri at California Institute of Technology. The work was supported by the MIT Energy Initiative and Siemens Gamesa Renewable Energy. More

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      in Environment

      Silk offers an alternative to some microplastics

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      Microplastics, tiny particles of plastic that are now found worldwide in the air, water, and soil, are increasingly recognized as a serious pollution threat, and have been found in the bloodstream of animals and people around the world.

      Some of these microplastics are intentionally added to a variety of products, including agricultural chemicals, paints, cosmetics, and detergents — amounting to an estimated 50,000 tons a year in the European Union alone, according to the European Chemicals Agency. The EU has already declared that these added, nonbiodegradable microplastics must be eliminated by 2025, so the search is on for suitable replacements, which do not currently exist.

      Now, a team of scientists at MIT and elsewhere has developed a system based on silk that could provide an inexpensive and easily manufactured substitute. The new process is described in a paper in the journal Small, written by MIT postdoc Muchun Liu, MIT professor of civil and environmental engineering Benedetto Marelli, and five others at the chemical company BASF in Germany and the U.S.

      The microplastics widely used in industrial products generally protect some specific active ingredient (or ingredients) from being degraded by exposure to air or moisture, until the time they are needed. They provide a slow release of the active ingredient for a targeted period of time and minimize adverse effects to its surroundings. For example, vitamins are often delivered in the form of microcapsules packed into a pill or capsule, and pesticides and herbicides are similarly enveloped. But the materials used today for such microencapsulation are plastics that persist in the environment for a long time. Until now, there has been no practical, economical substitute available that would biodegrade naturally.

      Much of the burden of environmental microplastics comes from other sources, such as the degradation over time of larger plastic objects such as bottles and packaging, and from the wear of car tires. Each of these sources may require its own kind of solutions for reducing its spread, Marelli says. The European Chemical Agency has estimated that the intentionally added microplastics represent approximately 10-15 percent of the total amount in the environment, but this source may be relatively easy to address using this nature-based biodegradable replacement, he says.

      “We cannot solve the whole microplastics problem with one solution that fits them all,” he says. “Ten percent of a big number is still a big number. … We’ll solve climate change and pollution of the world one percent at a time.”

      Unlike the high-quality silk threads used for fine fabrics, the silk protein used in the new alternative material is widely available and less expensive, Liu says. While silkworm cocoons must be painstakingly unwound to produce the fine threads needed for fabric, for this use, non-textile-quality cocoons can be used, and the silk fibers can simply be dissolved using a scalable water-based process. The processing is so simple and tunable that the resulting material can be adapted to work on existing manufacturing equipment, potentially providing a simple “drop in” solution using existing factories.

      Silk is recognized as safe for food or medical use, as it is nontoxic and degrades naturally in the body. In lab tests, the researchers demonstrated that the silk-based coating material could be used in existing, standard spray-based manufacturing equipment to make a standard water-soluble microencapsulated herbicide product, which was then tested in a greenhouse on a corn crop. The test showed it worked even better than an existing commercial product, inflicting less damage to the plants, Liu says.

      While other groups have proposed degradable encapsulation materials that may work at a small laboratory scale, Marelli says, “there is a strong need to achieve encapsulation of high-content actives to open the door to commercial use. The only way to have an impact is where we can not only replace a synthetic polymer with a biodegradable counterpart, but also achieve performance that is the same, if not better.”

      The secret to making the material compatible with existing equipment, Liu explains, is in the tunability of the silk material. By precisely adjusting the polymer chain arrangements of silk materials and addition of a surfactant, it is possible to fine-tune the properties of the resulting coatings once they dry out and harden. The material can be hydrophobic (water-repelling) even though it is made and processed in a water solution, or it can be hydrophilic (water-attracting), or anywhere in between, and for a given application it can be made to match the characteristics of the material it is being used to replace.

      In order to arrive at a practical solution, Liu had to develop a way of freezing the forming droplets of encapsulated materials as they were forming, to study the formation process in detail. She did this using a special spray-freezing system, and was able to observe exactly how the encapsulation works in order to control it better. Some of the encapsulated “payload” materials, whether they be pesticides or nutrients or enzymes, are water-soluble and some are not, and they interact in different ways with the coating material.

      “To encapsulate different materials, we have to study how the polymer chains interact and whether they are compatible with different active materials in suspension,” she says. The payload material and the coating material are mixed together in a solution and then sprayed. As droplets form, the payload tends to be embedded in a shell of the coating material, whether that’s the original synthetic plastic or the new silk material.

      The new method can make use of low-grade silk that is unusable for fabrics, and large quantities of which are currently discarded because they have no significant uses, Liu says. It can also use used, discarded silk fabric, diverting that material from being disposed of in landfills.

      Currently, 90 percent of the world’s silk production takes place in China, Marelli says, but that’s largely because China has perfected the production of the high-quality silk threads needed for fabrics. But because this process uses bulk silk and has no need for that level of quality, production could easily be ramped up in other parts of the world to meet local demand if this process becomes widely used, he says.

      “This elegant and clever study describes a sustainable and biodegradable silk-based replacement for microplastic encapsulants, which are a pressing environmental challenge,” says Alon Gorodetsky, an associate professor of chemical and biomolecular engineering at the University of California at Irvine, who was not associated with this research. “The modularity of the described materials and the scalability of the manufacturing processes are key advantages that portend well for translation to real-world applications.”

      This process “represents a potentially highly significant advance in active ingredient delivery for a range of industries, particularly agriculture,” says Jason White, director of the Connecticut Agricultural Experiment Station, who also was not associated with this work. “Given the current and future challenges related to food insecurity, agricultural production, and a changing climate, novel strategies such as this are greatly needed.”

      The research team also included Pierre-Eric Millard, Ophelie Zeyons, Henning Urch, Douglas Findley and Rupert Konradi from the BASF corporation, in Germany and in the U.S. The work was supported by BASF through the Northeast Research Alliance (NORA). More

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      in Environment

      Four researchers with MIT ties earn Schmidt Science Fellowships

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      Four researchers with MIT ties — Juncal Arbelaiz, Xiangkun (Elvis) Cao, Sandya Subramanian, and Heather Zlotnick ’17 — have been honored with competitive Schmidt Science Fellowships.

      Created in 2017, the fellows program aims to bring together the world’s brightest minds “to solve society’s toughest challenges.”

      The four MIT-affiliated researchers are among 29 Schmidt Science Fellows from around the world who will receive postdoctoral support for either one or two years with an annual stipend of $100,000, along with individualized mentoring and participation in the program’s Global Meeting Series. The fellows will also have opportunities to engage with thought-leaders from science, business, policy, and society. According to the award announcement, the fellows are expected to pursue research that shifts from the focus of their PhDs, to help expand and enhance their futures as scientific leaders.

      Juncal Arbelaiz is a PhD candidate in applied mathematics at MIT, who is completing her doctorate this summer. Her doctoral research at MIT is advised by Ali Jadbabaie, the JR East Professor of Engineering and head of the Department of Civil and Environmental Engineering; Anette Hosoi, the Neil and Jane Pappalardo Professor of Mechanical Engineering and associate dean of the School of Engineering; and Bassam Bamieh, professor of mechanical engineering and associate director of the Center for Control, Dynamical Systems, and Computation at the University of California at Santa Barbara. Arbelaiz’s research revolves around the design of optimal decentralized intelligence for spatially-distributed dynamical systems.

      “I cannot think of a better way to start my independent scientific career. I feel very excited and grateful for this opportunity,” says Arbelaiz. With her fellowship, she will enlist systems biology to explore how the nervous system encodes and processes sensory information to address future safety-critical artificial intelligence applications. “The Schmidt Science Fellowship will provide me with a unique opportunity to work at the intersection of biological and machine intelligence for two years and will be a steppingstone towards my longer-term objective of becoming a researcher in bio-inspired machine intelligence,” she says.

      Xiangkun (Elvis) Cao is currently a postdoc in the lab of T. Alan Hatton, the Ralph Landau Professor in Chemical Engineering, and an Impact Fellow at the MIT Climate and Sustainability Consortium. Cao received his PhD in mechanical engineering from Cornell University in 2021, during which he focused on microscopic precision in the simultaneous delivery of light and fluids by optofluidics, with advances relevant to health and sustainability applications. As a Schmidt Science Fellow, he plans to be co-advised by Hatton on carbon capture, and Ted Sargent, professor of chemistry at Northwestern University, on carbon utilization. Cao is passionate about integrated carbon capture and utilization (CCU) from molecular to process levels, machine learning to inspire smart CCU, and the nexus of technology, business, and policy for CCU.

      “The Schmidt Science Fellowship provides the perfect opportunity for me to work across disciplines to study integrated carbon capture and utilization from molecular to process levels,” Cao explains. “My vision is that by integrating carbon capture and utilization, we can concurrently make scientific discoveries and unlock economic opportunities while mitigating global climate change. This way, we can turn our carbon liability into an asset.”

      Sandya Subramanian, a 2021 PhD graduate of the Harvard-MIT Program in Health Sciences and Technology (HST) in the area of medical engineering and medical physics, is currently a postdoc at Stanford Data Science. She is focused on the topics of biomedical engineering, statistics, machine learning, neuroscience, and health care. Her research is on developing new technologies and methods to study the interactions between the brain, the autonomic nervous system, and the gut. “I’m extremely honored to receive the Schmidt Science Fellowship and to join the Schmidt community of leaders and scholars,” says Subramanian. “I’ve heard so much about the fellowship and the fact that it can open doors and give people confidence to pursue challenging or unique paths.”

      According to Subramanian, the autonomic nervous system and its interactions with other body systems are poorly understood but thought to be involved in several disorders, such as functional gastrointestinal disorders, Parkinson’s disease, diabetes, migraines, and eating disorders. The goal of her research is to improve our ability to monitor and quantify these physiologic processes. “I’m really interested in understanding how we can use physiological monitoring technologies to inform clinical decision-making, especially around the autonomic nervous system, and I look forward to continuing the work that I’ve recently started at Stanford as Schmidt Science Fellow,” she says. “A huge thank you to all of the mentors, colleagues, friends, and leaders I had the pleasure of meeting and working with at HST and MIT; I couldn’t have done this without everything I learned there.”

      Hannah Zlotnick ’17 attended MIT for her undergraduate studies, majoring in biological engineering with a minor in mechanical engineering. At MIT, Zlotnick was a student-athlete on the women’s varsity soccer team, a UROP student in Alan Grodzinsky’s laboratory, and a member of Pi Beta Phi. For her PhD, Zlotnick attended the University of Pennsylvania, and worked in Robert Mauck’s laboratory within the departments of Bioengineering and Orthopaedic Surgery.

      Zlotnick’s PhD research focused on harnessing remote forces, such as magnetism or gravity, to enhance engineered cartilage and osteochondral repair both in vitro and in large animal models. Zlotnick now plans to pivot to the field of biofabrication to create tissue models of the knee joint to assess potential therapeutics for osteoarthritis. “I am humbled to be a part of the Schmidt Science Fellows community, and excited to venture into the field of biofabrication,” Zlotnick says. “Hopefully this work uncovers new therapies for patients with inflammatory joint diseases.” More

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      in Environment

      Better living through multicellular life cycles

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      Cooperation is a core part of life for many organisms, ranging from microbes to complex multicellular life. It emerges when individuals share resources or partition a task in such a way that each derives a greater benefit when acting together than they could on their own. For example, birds and fish flock to evade predators, slime mold swarms to hunt for food and reproduce, and bacteria form biofilms to resist stress.

      Individuals must live in the same “neighborhood” to cooperate. For bacteria, this neighborhood can be as small as tens of microns. But in environments like the ocean, it’s rare for cells with the same genetic makeup to co-occur in the same neighborhood on their own. And this necessity poses a puzzle to scientists: In environments where survival hinges on cooperation, how do bacteria build their neighborhood?

      To study this problem, MIT professor Otto X. Cordero and colleagues took inspiration from nature: They developed a model system around a common coastal seawater bacterium that requires cooperation to eat sugars from brown algae. In the system, single cells were initially suspended in seawater too far away from other cells to cooperate. To share resources and grow, the cells had to find a mechanism of creating a neighborhood. “Surprisingly, each cell was able to divide and create its own neighborhood of clones by forming tightly packed clusters,” says Cordero, associate professor in the Department of Civil and Environmental Engineering.

      A new paper, published today in Current Biology, demonstrates how an algae-eating bacterium solves the engineering challenge of creating local cell density starting from a single-celled state.

      “A key discovery was the importance of phenotypic heterogeneity in supporting this surprising mechanism of clonal cooperation,” says Cordero, lead author of the new paper.

      Using a combination of microscopy, transcriptomics, and labeling experiments to profile a cellular metabolic state, the researchers found that cells phenotypically differentiate into a sticky “shell” population and a motile, carbon-storing “core.” The researchers propose that shell cells create the cellular neighborhood needed to sustain cooperation while core cells accumulate stores of carbon that support further clonal reproduction when the multicellular structure ruptures.

      This work addresses a key piece in the bigger challenge of understanding the bacterial processes that shape our earth, such as the cycling of carbon from dead organic matter back into food webs and the atmosphere. “Bacteria are fundamentally single cells, but often what they accomplish in nature is done through cooperation. We have much to uncover about what bacteria can accomplish together and how that differs from their capacity as individuals,” adds Cordero.

      Co-authors include Julia Schwartzman and Ali Ebrahimi, former postdocs in the Cordero Lab. Other co-authors are Gray Chadwick, a former graduate student at Caltech; Yuya Sato, a senior researcher at Japan’s National Institute of Advanced Industrial Science and Technology; Benjamin Roller, a current postdoc at the University of Vienna; and Victoria Orphan of Caltech.

      Funding was provided by the Simons Foundation. Individual authors received support from the Swiss National Science Foundation, Japan Society for the Promotion of Science, the U.S. National Science Foundation, the Kavli Institute of Theoretical Physics, and the National Institutes of Health. More

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      in Environment

      Study finds natural sources of air pollution exceed air quality guidelines in many regions

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      Alongside climate change, air pollution is one of the biggest environmental threats to human health. Tiny particles known as particulate matter or PM2.5 (named for their diameter of just 2.5 micrometers or less) are a particularly hazardous type of pollutant. These particles are produced from a variety of sources, including wildfires and the burning of fossil fuels, and can enter our bloodstream, travel deep into our lungs, and cause respiratory and cardiovascular damage. Exposure to particulate matter is responsible for millions of premature deaths globally every year.

      In response to the increasing body of evidence on the detrimental effects of PM2.5, the World Health Organization (WHO) recently updated its air quality guidelines, lowering its recommended annual PM2.5 exposure guideline by 50 percent, from 10 micrograms per meter cubed (μm3) to 5 μm3. These updated guidelines signify an aggressive attempt to promote the regulation and reduction of anthropogenic emissions in order to improve global air quality.

      A new study by researchers in the MIT Department of Civil and Environmental Engineering explores if the updated air quality guideline of 5 μm3 is realistically attainable across different regions of the world, particularly if anthropogenic emissions are aggressively reduced. 

      The first question the researchers wanted to investigate was to what degree moving to a no-fossil-fuel future would help different regions meet this new air quality guideline.

      “The answer we found is that eliminating fossil-fuel emissions would improve air quality around the world, but while this would help some regions come into compliance with the WHO guidelines, for many other regions high contributions from natural sources would impede their ability to meet that target,” says senior author Colette Heald, the Germeshausen Professor in the MIT departments of Civil and Environmental Engineering, and Earth, Atmospheric and Planetary Sciences. 

      The study by Heald, Professor Jesse Kroll, and graduate students Sidhant Pai and Therese Carter, published June 6 in the journal Environmental Science and Technology Letters, finds that over 90 percent of the global population is currently exposed to average annual concentrations that are higher than the recommended guideline. The authors go on to demonstrate that over 50 percent of the world’s population would still be exposed to PM2.5 concentrations that exceed the new air quality guidelines, even in the absence of all anthropogenic emissions.

      This is due to the large natural sources of particulate matter — dust, sea salt, and organics from vegetation — that still exist in the atmosphere when anthropogenic emissions are removed from the air. 

      “If you live in parts of India or northern Africa that are exposed to large amounts of fine dust, it can be challenging to reduce PM2.5 exposures below the new guideline,” says Sidhant Pai, co-lead author and graduate student. “This study challenges us to rethink the value of different emissions abatement controls across different regions and suggests the need for a new generation of air quality metrics that can enable targeted decision-making.”

      The researchers conducted a series of model simulations to explore the viability of achieving the updated PM2.5 guidelines worldwide under different emissions reduction scenarios, using 2019 as a representative baseline year. 

      Their model simulations used a suite of different anthropogenic sources that could be turned on and off to study the contribution of a particular source. For instance, the researchers conducted a simulation that turned off all human-based emissions in order to determine the amount of PM2.5 pollution that could be attributed to natural and fire sources. By analyzing the chemical composition of the PM2.5 aerosol in the atmosphere (e.g., dust, sulfate, and black carbon), the researchers were also able to get a more accurate understanding of the most important PM2.5 sources in a particular region. For example, elevated PM2.5 concentrations in the Amazon were shown to predominantly consist of carbon-containing aerosols from sources like deforestation fires. Conversely, nitrogen-containing aerosols were prominent in Northern Europe, with large contributions from vehicles and fertilizer usage. The two regions would thus require very different policies and methods to improve their air quality. 

      “Analyzing particulate pollution across individual chemical species allows for mitigation and adaptation decisions that are specific to the region, as opposed to a one-size-fits-all approach, which can be challenging to execute without an understanding of the underlying importance of different sources,” says Pai. 

      When the WHO air quality guidelines were last updated in 2005, they had a significant impact on environmental policies. Scientists could look at an area that was not in compliance and suggest high-level solutions to improve the region’s air quality. But as the guidelines have tightened, globally-applicable solutions to manage and improve air quality are no longer as evident. 

      “Another benefit of speciating is that some of the particles have different toxicity properties that are correlated to health outcomes,” says Therese Carter, co-lead author and graduate student. “It’s an important area of research that this work can help motivate. Being able to separate out that piece of the puzzle can provide epidemiologists with more insights on the different toxicity levels and the impact of specific particles on human health.”

      The authors view these new findings as an opportunity to expand and iterate on the current guidelines.  

      “Routine and global measurements of the chemical composition of PM2.5 would give policymakers information on what interventions would most effectively improve air quality in any given location,” says Jesse Kroll, a professor in the MIT departments of Civil and Environmental Engineering and Chemical Engineering. “But it would also provide us with new insights into how different chemical species in PM2.5 affect human health.”

      “I hope that as we learn more about the health impacts of these different particles, our work and that of the broader atmospheric chemistry community can help inform strategies to reduce the pollutants that are most harmful to human health,” adds Heald. More

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      in Energy

      MIT Climate and Sustainability Consortium announces recipients of inaugural MCSC Seed Awards

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      The MIT Climate and Sustainability Consortium (MCSC) has awarded 20 projects a total of $5 million over two years in its first-ever 2022 MCSC Seed Awards program. The winning projects are led by principal investigators across all five of MIT’s schools.

      The goal of the MCSC Seed Awards is to engage MIT researchers and link the economy-wide work of the consortium to ongoing and emerging climate and sustainability efforts across campus. The program offers further opportunity to build networks among the awarded projects to deepen the impact of each and ensure the total is greater than the sum of its parts.

      For example, to drive progress under the awards category Circularity and Materials, the MCSC can facilitate connections between the technologists at MIT who are developing recovery approaches for metals, plastics, and fiber; the urban planners who are uncovering barriers to reuse; and the engineers, who will look for efficiency opportunities in reverse supply chains.

      “The MCSC Seed Awards are designed to complement actions previously outlined in Fast Forward: MIT’s Climate Action Plan for the Decade and, more specifically, the Climate Grand Challenges,” says Anantha P. Chandrakasan, dean of the MIT School of Engineering, Vannevar Bush Professor of Electrical Engineering and Computer Science, and chair of the MIT Climate and Sustainability Consortium. “In collaboration with seed award recipients and MCSC industry members, we are eager to engage in interdisciplinary exploration and propel urgent advancements in climate and sustainability.” 

      By supporting MIT researchers with expertise in economics, infrastructure, community risk assessment, mobility, and alternative fuels, the MCSC will accelerate implementation of cross-disciplinary solutions in the awards category Decarbonized and Resilient Value Chains. Enhancing Natural Carbon Sinks and building connections to local communities will require associations across experts in ecosystem change, biodiversity, improved agricultural practice and engagement with farmers, all of which the consortium can begin to foster through the seed awards.

      “Funding opportunities across campus has been a top priority since launching the MCSC,” says Jeremy Gregory, MCSC executive director. “It is our honor to support innovative teams of MIT researchers through the inaugural 2022 MCSC Seed Awards program.”

      The winning projects are tightly aligned with the MCSC’s areas of focus, which were derived from a year of highly engaged collaborations with MCSC member companies. The projects apply across the member’s climate and sustainability goals.

      The MCSC’s 16 member companies span many industries, and since early 2021, have met with members of the MIT community to define focused problem statements for industry-specific challenges, identify meaningful partnerships and collaborations, and develop clear and scalable priorities. Outcomes from these collaborations laid the foundation for the focus areas, which have shaped the work of the MCSC. Specifically, the MCSC Industry Advisory Board engaged with MIT on key strategic directions, and played a critical role in the MCSC’s series of interactive events. These included virtual workshops hosted last summer, each on a specific topic that allowed companies to work with MIT and each other to align key assumptions, identify blind spots in corporate goal-setting, and leverage synergies between members, across industries. The work continued in follow-up sessions and an annual symposium.

      “We are excited to see how the seed award efforts will help our member companies reach or even exceed their ambitious climate targets, find new cross-sector links among each other, seek opportunities to lead, and ripple key lessons within their industry, while also deepening the Institute’s strong foundation in climate and sustainability research,” says Elsa Olivetti, the Esther and Harold E. Edgerton Associate Professor in Materials Science and Engineering and MCSC co-director.

      As the seed projects take shape, the MCSC will provide ongoing opportunities for awardees to engage with the Industry Advisory Board and technical teams from the MCSC member companies to learn more about the potential for linking efforts to support and accelerate their climate and sustainability goals. Awardees will also have the chance to engage with other members of the MCSC community, including its interdisciplinary Faculty Steering Committee.

      “One of our mantras in the MCSC is to ‘amplify and extend’ existing efforts across campus; we’re always looking for ways to connect the collaborative industry relationships we’re building and the work we’re doing with other efforts on campus,” notes Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems, head of the Department of Materials Science and Engineering, and MCSC co-director. “We feel the urgency as well as the potential, and we don’t want to miss opportunities to do more and go faster.”

      The MCSC Seed Awards complement the Climate Grand Challenges, a new initiative to mobilize the entire MIT research community around developing the bold, interdisciplinary solutions needed to address difficult, unsolved climate problems. The 27 finalist teams addressed four broad research themes, which align with the MCSC’s focus areas. From these finalist teams, five flagship projects were announced in April 2022.

      The parallels between MCSC’s focus areas and the Climate Grand Challenges themes underscore an important connection between the shared long-term research interests of industry and academia. The challenges that some of the world’s largest and most influential companies have identified are complementary to MIT’s ongoing research and innovation — highlighting the tremendous opportunity to develop breakthroughs and scalable solutions quickly and effectively. Special Presidential Envoy for Climate John Kerry underscored the importance of developing these scalable solutions, including critical new technology, during a conversation with MIT President L. Rafael Reif at MIT’s first Climate Grand Challenges showcase event last month.

      Both the MCSC Seed Awards and the Climate Grand Challenges are part of MIT’s larger commitment and initiative to combat climate change; this was underscored in “Fast Forward: MIT’s Climate Action Plan for the Decade,” which the Institute published in May 2021.

      The project titles and research leads for each of the 20 awardees listed below are categorized by MCSC focus area.

      Decarbonized and resilient value chains

      “Collaborative community mapping toolkit for resilience planning,” led by Miho Mazereeuw, associate professor of architecture and urbanism in the Department of Architecture and director of the Urban Risk Lab (a research lead on Climate Grand Challenges flagship project) and Nicholas de Monchaux, professor and department head in the Department of Architecture
      “CP4All: Fast and local climate projections with scientific machine learning — towards accessibility for all of humanity,” led by Chris Hill, principal research scientist in the Department of Earth, Atmospheric and Planetary Sciences and Dava Newman, director of the MIT Media Lab and the Apollo Program Professor in the Department of Aeronautics and Astronautics
      “Emissions reductions and productivity in U.S. manufacturing,” led by Mert Demirer, assistant professor of applied economics at the MIT Sloan School of Management and Jing Li, assistant professor and William Barton Rogers Career Development Chair of Energy Economics in the MIT Sloan School of Management
      “Logistics electrification through scalable and inter-operable charging infrastructure: operations, planning, and policy,” led by Alex Jacquillat, the 1942 Career Development Professor and assistant professor of operations research and statistics in the MIT Sloan School of Management
      “Powertrain and system design for LOHC-powered long-haul trucking,” led by William Green, the Hoyt Hottel Professor in Chemical Engineering in the Department of Chemical Engineering and postdoctoral officer, and Wai K. Cheng, professor in the Department of Mechanical Engineering and director of the Sloan Automotive Laboratory
      “Sustainable Separation and Purification of Biochemicals and Biofuels using Membranes,” led by John Lienhard, the Abdul Latif Jameel Professor of Water in the Department of Mechanical Engineering, director of the Abdul Latif Jameel Water and Food Systems Lab, and director of the Rohsenow Kendall Heat Transfer Laboratory; and Nicolas Hadjiconstantinou, professor in the Department of Mechanical Engineering, co-director of the Center for Computational Science and Engineering, associate director of the Center for Exascale Simulation of Materials in Extreme Environments, and graduate officer
      “Toolkit for assessing the vulnerability of industry infrastructure siting to climate change,” led by Michael Howland, assistant professor in the Department of Civil and Environmental Engineering

      Circularity and Materials

      “Colorimetric Sulfidation for Aluminum Recycling,” led by Antoine Allanore, associate professor of metallurgy in the Department of Materials Science and Engineering
      “Double Loop Circularity in Materials Design Demonstrated on Polyurethanes,” led by Brad Olsen, the Alexander and I. Michael Kasser (1960) Professor and graduate admissions co-chair in the Department of Chemical Engineering, and Kristala Prather, the Arthur Dehon Little Professor and department executive officer in the Department of Chemical Engineering
      “Engineering of a microbial consortium to degrade and valorize plastic waste,” led by Otto Cordero, associate professor in the Department of Civil and Environmental Engineering, and Desiree Plata, the Gilbert W. Winslow (1937) Career Development Professor in Civil Engineering and associate professor in the Department of Civil and Environmental Engineering
      “Fruit-peel-inspired, biodegradable packaging platform with multifunctional barrier properties,” led by Kripa Varanasi, professor in the Department of Mechanical Engineering
      “High Throughput Screening of Sustainable Polyesters for Fibers,” led by Gregory Rutledge, the Lammot du Pont Professor in the Department of Chemical Engineering, and Brad Olsen, Alexander and I. Michael Kasser (1960) Professor and graduate admissions co-chair in the Department of Chemical Engineering
      “Short-term and long-term efficiency gains in reverse supply chains,” led by Yossi Sheffi, the Elisha Gray II Professor of Engineering Systems, professor in the Department of Civil and Environmental Engineering, and director of the Center for Transportation and Logistics
      The costs and benefits of circularity in building construction, led by Siqi Zheng, the STL Champion Professor of Urban and Real Estate Sustainability at the MIT Center for Real Estate and Department of Urban Studies and Planning, faculty director of the MIT Center for Real Estate, and faculty director for the MIT Sustainable Urbanization Lab; and Randolph Kirchain, principal research scientist and co-director of MIT Concrete Sustainability Hub

      Natural carbon sinks

      “Carbon sequestration through sustainable practices by smallholder farmers,” led by Joann de Zegher, the Maurice F. Strong Career Development Professor and assistant professor of operations management in the MIT Sloan School of Management, and Karen Zheng the George M. Bunker Professor and associate professor of operations management in the MIT Sloan School of Management
      “Coatings to protect and enhance diverse microbes for improved soil health and crop yields,” led by Ariel Furst, the Raymond A. (1921) And Helen E. St. Laurent Career Development Professor of Chemical Engineering in the Department of Chemical Engineering, and Mary Gehring, associate professor of biology in the Department of Biology, core member of the Whitehead Institute for Biomedical Research, and graduate officer
      “ECO-LENS: Mainstreaming biodiversity data through AI,” led by John Fernández, professor of building technology in the Department of Architecture and director of MIT Environmental Solutions Initiative
      “Growing season length, productivity, and carbon balance of global ecosystems under climate change,” led by Charles Harvey, professor in the Department of Civil and Environmental Engineering, and César Terrer, assistant professor in the Department of Civil and Environmental Engineering

      Social dimensions and adaptation

      “Anthro-engineering decarbonization at the million-person scale,” led by Manduhai Buyandelger, professor in the Anthropology Section, and Michael Short, the Class of ’42 Associate Professor of Nuclear Science and Engineering in the Department of Nuclear Science and Engineering
      “Sustainable solutions for climate change adaptation: weaving traditional ecological knowledge and STEAM,” led by Janelle Knox-Hayes, the Lister Brothers Associate Professor of Economic Geography and Planning and head of the Environmental Policy and Planning Group in the Department of Urban Studies and Planning, and Miho Mazereeuw, associate professor of architecture and urbanism in the Department of Architecture and director of the Urban Risk Lab (a research lead on a Climate Grand Challenges flagship project) More