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    To design better water filters, MIT engineers look to manta rays

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    Filter feeders are everywhere in the animal world, from tiny crustaceans and certain types of coral and krill, to various molluscs, barnacles, and even massive basking sharks and baleen whales. Now, MIT engineers have found that one filter feeder has evolved to sift food in ways that could improve the design of industrial water filters.In a paper appearing this week in the Proceedings of the National Academy of Sciences, the team characterizes the filter-feeding mechanism of the mobula ray — a family of aquatic rays that includes two manta species and seven devil rays. Mobula rays feed by swimming open-mouthed through plankton-rich regions of the ocean and filtering plankton particles into their gullet as water streams into their mouths and out through their gills.The floor of the mobula ray’s mouth is lined on either side with parallel, comb-like structures, called plates, that siphon water into the ray’s gills. The MIT team has shown that the dimensions of these plates may allow for incoming plankton to bounce all the way across the plates and further into the ray’s cavity, rather than out through the gills. What’s more, the ray’s gills absorb oxygen from the outflowing water, helping the ray to simultaneously breathe while feeding.“We show that the mobula ray has evolved the geometry of these plates to be the perfect size to balance feeding and breathing,” says study author Anette “Peko” Hosoi, the Pappalardo Professor of Mechanical Engineering at MIT.The engineers fabricated a simple water filter modeled after the mobula ray’s plankton-filtering features. They studied how water flowed through the filter when it was fitted with 3D-printed plate-like structures. The team took the results of these experiments and drew up a blueprint, which they say designers can use to optimize industrial cross-flow filters, which are broadly similar in configuration to that of the mobula ray.“We want to expand the design space of traditional cross-flow filtration with new knowledge from the manta ray,” says lead author and MIT postdoc Xinyu Mao PhD ’24. “People can choose a parameter regime of the mobula ray so they could potentially improve overall filter performance.”Hosoi and Mao co-authored the new study with Irmgard Bischofberger, associate professor of mechanical engineering at MIT.A better trade-offThe new study grew out of the group’s focus on filtration during the height of the Covid pandemic, when the researchers were designing face masks to filter out the virus. Since then, Mao has shifted focus to study filtration in animals and how certain filter-feeding mechanisms might improve filters used in industry, such as in water treatment plants.Mao observed that any industrial filter must strike a balance between permeability (how easily fluid can flow through a filter), and selectivity (how successful a filter is at keeping out particles of a target size). For instance, a membrane that is studded with large holes might be highly permeable, meaning a lot of water can be pumped through using very little energy. However, the membrane’s large holes would let many particles through, making it very low in selectivity. Likewise, a membrane with much smaller pores would be more selective yet also require more energy to pump the water through the smaller openings.“We asked ourselves, how do we do better with this tradeoff between permeability and selectivity?” Hosoi says.As Mao looked into filter-feeding animals, he found that the mobula ray has struck an ideal balance between permeability and selectivity: The ray is highly permeable, in that it can let water into its mouth and out through its gills quickly enough to capture oxygen to breathe. At the same time, it is highly selective, filtering and feeding on plankton rather than letting the particles stream out through the gills.The researchers realized that the ray’s filtering features are broadly similar to that of industrial cross-flow filters. These filters are designed such that fluid flows across a permeable membrane that lets through most of the fluid, while any polluting particles continue flowing across the membrane and eventually out into a reservoir of waste.The team wondered whether the mobula ray might inspire design improvements to industrial cross-flow filters. For that, they took a deeper dive into the dynamics of mobula ray filtration.A vortex keyAs part of their new study, the team fabricated a simple filter inspired by the mobula ray. The filter’s design is what engineers refer to as a “leaky channel” — effectively, a pipe with holes along its sides. In this case, the team’s “channel” consists of two flat, transparent acrylic plates that are glued together at the edges, with a slight opening between the plates through which fluid can be pumped. At one end of the channel, the researchers inserted 3D-printed structures resembling the grooved plates that run along the floor of the mobula ray’s mouth.The team then pumped water through the channel at various rates, along with colored dye to visualize the flow. They took images across the channel and observed an interesting transition: At slow pumping rates, the flow was “very peaceful,” and fluid easily slipped through the grooves in the printed plates and out into a reservoir. When the researchers increased the pumping rate, the faster-flowing fluid did not slip through, but appeared to swirl at the mouth of each groove, creating a vortex, similar to a small knot of hair between the tips of a comb’s teeth.“This vortex is not blocking water, but it is blocking particles,” Hosoi explains. “Whereas in a slower flow, particles go through the filter with the water, at higher flow rates, particles try to get through the filter but are blocked by this vortex and are shot down the channel instead. The vortex is helpful because it prevents particles from flowing out.”The team surmised that vortices are the key to mobula rays’ filter-feeding ability. The ray is able to swim at just the right speed that water, streaming into its mouth, can form vortices between the grooved plates. These vortices effectively block any plankton particles — even those that are smaller than the space between plates. The particles then bounce across the plates and head further into the ray’s cavity, while the rest of the water can still flow between the plates and out through the gills.The researchers used the results of their experiments, along with dimensions of the filtering features of mobula rays, to develop a blueprint for cross-flow filtration.“We have provided practical guidance on how to actually filter as the mobula ray does,” Mao offers.“You want to design a filter such that you’re in the regime where you generate vortices,” Hosoi says. “Our guidelines tell you: If you want your plant to pump at a certain rate, then your filter has to have a particular pore diameter and spacing to generate vortices that will filter out particles of this size. The mobula ray is giving us a really nice rule of thumb for rational design.”This work was supported, in part, by the U.S. National Institutes of Health, and the Harvey P. Greenspan Fellowship Fund.  More

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      Making agriculture more resilient to climate change

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      As Earth’s temperature rises, agricultural practices will need to adapt. Droughts will likely become more frequent, and some land may no longer be arable. On top of that is the challenge of feeding an ever-growing population without expanding the production of fertilizer and other agrochemicals, which have a large carbon footprint that is contributing to the overall warming of the planet.Researchers across MIT are taking on these agricultural challenges from a variety of angles, from engineering plants that sound an alarm when they’re under stress to making seeds more resilient to drought. These types of technologies, and more yet to be devised, will be essential to feed the world’s population as the climate changes.“After water, the first thing we need is food. In terms of priority, there is water, food, and then everything else. As we are trying to find new strategies to support a world of 10 billion people, it will require us to invent new ways of making food,” says Benedetto Marelli, an associate professor of civil and environmental engineering at MIT.Marelli is the director of one of the six missions of the recently launched Climate Project at MIT, which focus on research areas such as decarbonizing industry and building resilient cities. Marelli directs the Wild Cards mission, which aims to identify unconventional solutions that are high-risk and high-reward.Drawing on expertise from a breadth of fields, MIT is well-positioned to tackle the challenges posed by climate change, Marelli says. “Bringing together our strengths across disciplines, including engineering, processing at scale, biological engineering, and infrastructure engineering, along with humanities, science, and economics, presents a great opportunity.”Protecting seeds from droughtMarelli, who began his career as a biomedical engineer working on regenerative medicine, is now developing ways to boost crop yields by helping seeds to survive and germinate during drought conditions, or in soil that has been depleted of nutrients. To achieve that, he has devised seed coatings, based on silk and other polymers, that can envelop and nourish seeds during the critical germination process.

      A new seed-coating process could facilitate agriculture on marginal arid lands by enabling the seeds to retain any available water.

      In healthy soil, plants have access to nitrogen, phosphates, and other nutrients that they need, many of which are supplied by microbes that live in the soil. However, in soil that has suffered from drought or overfarming, these nutrients are lacking. Marelli’s idea was to coat the seeds with a polymer that can be embedded with plant-growth-promoting bacteria that “fix” nitrogen by absorbing it from the air and making it available to plants. The microbes can also make other necessary nutrients available to plants.For the first generation of the seed coatings, he embedded these microbes in coatings made of silk — a material that he had previously shown can extend the shelf life of produce, meat, and other foods. In his lab at MIT, Marelli has shown that the seed coatings can help germinating plants survive drought, ultraviolet light exposure, and high salinity.Now, working with researchers at the Mohammed VI Polytechnic University in Morocco, he is adapting the approach to crops native to Morocco, a country that has experienced six consecutive years of drought due a drop in rainfall linked to climate change.For these studies, the researchers are using a biopolymer coating derived from food waste that can be easily obtained in Morocco, instead of silk.“We’re working with local communities to extract the biopolymers, to try to have a process that works at scale so that we make materials that work in that specific environment.” Marelli says. “We may come up with an idea here at MIT within a high-resource environment, but then to work there, we need to talk with the local communities, with local stakeholders, and use their own ingenuity and try to match our solution with something that could actually be applied in the local environment.”Microbes as fertilizersWhether they are experiencing drought or not, crops grow much better when synthetic fertilizers are applied. Although it’s essential to most farms, applying fertilizer is expensive and has environmental consequences. Most of the world’s fertilizer is produced using the Haber-Bosch process, which converts nitrogen and hydrogen to ammonia at high temperatures and pressures. This energy intensive process accounts for about 1.5 percent of the world’s greenhouse gas emissions, and the transportation required to deliver it to farms around the world adds even more emissions.Ariel Furst, the Paul M. Cook Career Development Assistant Professor of Chemical Engineering at MIT, is developing a microbial alternative to the Haber-Bosch process. Some farms have experimented with applying nitrogen-fixing bacteria directly to the roots of their crops, which has shown some success. However, the microbes are too delicate to be stored long-term or shipped anywhere, so they must be produced in a bioreactor on the farm.

      MIT chemical engineers devised a metal-organic coating that protects bacterial cells from damage without impeding their growth or function.

      To overcome those challenges, Furst has developed a way to coat the microbes with a protective shell that prevents them from being destroyed by heat or other stresses. The coating also protects microbes from damage caused by freeze-drying — a process that would make them easier to transport.The coatings can vary in composition, but they all consist of two components. One is a metal such as iron, manganese, or zinc, and the other is a polyphenol — a type of plant-derived organic compound that includes tannins and other antioxidants. These two components self-assemble into a protective shell that encapsulates bacteria.

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      Mighty Microbes: The Power of Protective PolymersVideo: Chemistry Shorts

      “These microbes would be delivered with the seeds, so it would remove the need for fertilizing mid-growing. It also reduces the cost and provides more autonomy to the farmers and decreases carbon emissions associated with agriculture,” Furst says. “We think it’ll be a way to make agriculture completely regenerative, so to bring back soil health while also boosting crop yields and the nutrient density of the crops.”Furst has founded a company called Seia Bio, which is working on commercializing the coated microbes and has begun testing them on farms in Brazil. In her lab, Furst is also working on adapting the approach to coat microbes that can capture carbon dioxide from the atmosphere and turn it into limestone, which helps to raise the soil pH.“It can help change the pH of soil to stabilize it, while also being a way to effectively perform direct air capture of CO2,” she says. “Right now, farmers may truck in limestone to change the pH of soil, and so you’re creating a lot of emissions to bring something in that microbes can do on their own.”Distress sensors for plantsSeveral years ago, Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT, began to explore the idea of using plants themselves as sensors that could reveal when they’re in distress. When plants experience drought, attack by pests, or other kinds of stress, they produce hormones and other signaling molecules to defend themselves.Strano, whose lab specializes in developing tiny sensors for a variety of molecules, wondered if such sensors could be deployed inside plants to pick up those distress signals. To create their sensors, Strano’s lab takes advantage of the special properties of single-walled carbon nanotubes, which emit fluorescent light. By wrapping the tubes with different types of polymers, the sensors can be tuned to detect specific targets, giving off a fluorescent signal when the target is present.For use in plants, Strano and his colleagues created sensors that could detect signaling molecules such as salicylic acid and hydrogen peroxide. They then showed that these sensors could be inserted into the underside of plant leaves, without harming the plants. Once embedded in the mesophyll of the leaves, the sensors can pick up a variety of signals, which can be read with an infrared camera.

      Sensors that detect plant signaling molecules can reveal when crops are experiencing too much light or heat, or attack from insects or microbes.

      These sensors can reveal, in real-time, whether a plant is experiencing a variety of stresses. Until now, there hasn’t been a way to get that information fast enough for farmers to act on it.“What we’re trying to do is make tools that get information into the hands of farmers very quickly, fast enough for them to make adaptive decisions that can increase yield,” Strano says. “We’re in the middle of a revolution of really understanding the way in which plants internally communicate and communicate with other plants.”This kind of sensing could be deployed in fields, where it could help farmers respond more quickly to drought and other stresses, or in greenhouses, vertical farms, and other types of indoor farms that use technology to grow crops in a controlled environment.Much of Strano’s work in this area has been conducted with the support of the U.S. Department of Agriculture (USDA) and as part of the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) program at the Singapore-MIT Alliance for Research and Technology (SMART), and sensors have been deployed in tests in crops at a controlled environment farm in Singapore called Growy.“The same basic kinds of tools can help detect problems in open field agriculture or in controlled environment agriculture,” Strano says. “They both suffer from the same problem, which is that the farmers get information too late to prevent yield loss.”Reducing pesticide usePesticides represent another huge financial expense for farmers: Worldwide, farmers spend about $60 billion per year on pesticides. Much of this pesticide ends up accumulating in water and soil, where it can harm many species, including humans. But, without using pesticides, farmers may lose more than half of their crops.Kripa Varanasi, an MIT professor of mechanical engineering, is working on tools that can help farmers measure how much pesticide is reaching their plants, as well as technologies that can help pesticides adhere to plants more efficiently, reducing the amount that runs off into soil and water.Varanasi, whose research focuses on interactions between liquid droplets and surfaces, began to think about applying his work to agriculture more than a decade ago, after attending a conference at the USDA. There, he was inspired to begin developing ways to improve the efficiency of pesticide application by optimizing the interactions that occur at leaf surfaces.“Billions of drops of pesticide are being sprayed on every acre of crop, and only a small fraction is ultimately reaching and staying on target. This seemed to me like a problem that we could help to solve,” he says.Varanasi and his students began exploring strategies to make drops of pesticide stick to leaves better, instead of bouncing off. They found that if they added polymers with positive and negative charges, the oppositely charged droplets would form a hydrophilic (water-attracting) coating on the leaf surface, which helps the next droplets applied to stick to the leaf.

      AgZen has developed a system for farming that can monitor exactly how much of the sprayed chemicals adheres to plants, in real time, as the sprayer drives through a field.

      Later, they developed an easier-to-use technology in which a surfactant is added to the pesticide before spraying. When this mixture is sprayed through a special nozzle, it forms tiny droplets that are “cloaked” in surfactant. The surfactant helps the droplets to stick to the leaves within a few milliseconds, without bouncing off.In 2020, Varanasi and Vishnu Jayaprakash SM ’19, PhD ’22 founded a company called AgZen to commercialize their technologies and get them into the hands of farmers. They incorporated their ideas for improving pesticide adhesion into a product called EnhanceCoverage.During the testing for this product, they realized that there weren’t any good ways to measure how many of the droplets were staying on the plant. That led them to develop a product known as RealCoverage, which is based on machine vision. It can be attached to any pesticide sprayer and offer real-time feedback on what percentage of the pesticide droplets are sticking to and staying on every leaf.RealCoverage was used on 65,000 acres of farmland across the United States in 2024, from soybeans in Iowa to cotton in Georgia. Farmers who used the product were able to reduce their pesticide use by 30 to 50 percent, by using the data to optimize delivery and, in some cases, even change what chemicals were sprayed.He hopes that the EnhanceCoverage product, which is expected to become available in 2025, will help farmers further reduce their pesticide use.“Our mission here is to help farmers with savings while helping them achieve better yields. We have found a way to do all this while also reducing waste and the amount of chemicals that we put into our atmosphere and into our soils and into our water,” Varanasi says. “This is the MIT approach: to figure out what are the real issues and how to come up with solutions. Now we have a tool and I hope that it’s deployed everywhere and everyone gets the benefit from it.” More

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      in Security

      Aspiring to sustainable development

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      In a first for both universities, MIT undergraduates are engaged in research projects at the Universidad del Valle de Guatemala (UVG), while MIT scholars are collaborating with UVG undergraduates on in-depth field studies in Guatemala.These pilot projects are part of a larger enterprise, called ASPIRE (Achieving Sustainable Partnerships for Innovation, Research, and Entrepreneurship). Funded by the U.S. Agency for International Development, this five-year, $15-million initiative brings together MIT, UVG, and the Guatemalan Exporters Association to promote sustainable solutions to local development challenges.“This research is yielding insights into our understanding of how to design with and for marginalized people, specifically Indigenous people,” says Elizabeth Hoffecker, co-principal investigator of ASPIRE at MIT and director of the MIT Local Innovation Group.The students’ work is bearing fruit in the form of publications and new products — directly advancing ASPIRE’s goals to create an innovation ecosystem in Guatemala that can be replicated elsewhere in Central and Latin America.For the students, the project offers rewards both tangible and inspirational.“My experience allowed me to find my interest in local innovation and entrepreneurship,” says Ximena Sarmiento García, a fifth-year undergraduate at UVG majoring in anthropology. Supervised by Hoffecker, Sarmiento García says, “I learned how to inform myself, investigate, and find solutions — to become a researcher.”Sandra Youssef, a rising junior in mechanical engineering at MIT, collaborated with UVG researchers and Indigenous farmers to design a mobile cart to improve the harvest yield of snow peas. “It was perfect for me,” she says. “My goal was to use creative, new technologies and science to make a dent in difficult problems.”Remote and effectiveKendra Leith, co-principal investigator of ASPIRE, and associate director for research at MIT D-Lab, shaped the MIT-based undergraduate research opportunities (UROPs) in concert with UVG colleagues. “Although MIT students aren’t currently permitted to travel to Guatemala, I wanted them to have an opportunity to apply their experience and knowledge to address real-world challenges,” says Leith. “The Covid pandemic prepared them and their counterparts at UVG for effective remote collaboration — the UROPs completed remarkably productive research projects over Zoom and met our goals for them.”MIT students participated in some of UVG’s most ambitious ASPIRE research. For instance, Sydney Baller, a rising sophomore in mechanical engineering, joined a team of Indigenous farmers and UVG mechanical engineers investigating the manufacturing process and potential markets for essential oils extracted from thyme, rosemary, and chamomile plants.“Indigenous people have thousands of years working with plant extracts and ancient remedies,” says Baller. “There is promising history there that would be important to follow up with more modern research.”Sandra Youssef used computer-aided design and manufacturing to realize a design created in a hackathon by snow pea farmers. “Our cart had to hold 495 pounds of snow peas without collapsing or overturning, navigate narrow paths on hills, and be simple and inexpensive to assemble,” she says. The snow pea producers have tested two of Youssef’s designs, built by a team at UVG led by Rony Herrarte, a faculty member in the department of mechanical engineering.From waste to filterTwo MIT undergraduates joined one of UVG’s long-standing projects: addressing pollution in Guatemala’s water. The research seeks to use chitosan molecules, extracted from shrimp shells, for bioremediation of heavy metals and other water contaminants. These shells are available in abundance, left as waste by the country’s shrimp industry.Sophomores Ariana Hodlewsky, majoring in chemical engineering, and Paolo Mangiafico, majoring in brain and cognitive sciences, signed on to work with principal investigator and chemistry department instructor Allan Vásquez (UVG) on filtration systems utilizing chitosan.“The team wants to find a cost-effective product rural communities, most at risk from polluted water, can use in homes or in town water systems,” says Mangiafico. “So we have been investigating different technologies for water filtration, and analyzing the Guatemalan and U.S. markets to understand the regulations and opportunities that might affect introduction of a chitosan-based product.”“Our research into how different communities use water and into potential consumers and pitfalls sets the scene for prototypes UVG wants to produce,” says Hodlewsky.Lourdes Figueroa, UVG ASPIRE project manager for technology transfer, found their assistance invaluable.“Paolo and Ariana brought the MIT culture and mindset to the project,” she says. “They wanted to understand not only how the technology works, but the best ways of getting the technology out of the lab to make it useful.”This was an “Aha!” moment, says Figueroa. “The MIT students made a major contribution to both the engineering and marketing sides by emphasizing that you have to think about how to guarantee the market acceptance of the technology while it is still under development.”Innovation ecosystemsUVG’s three campuses have served as incubators for problem-solving innovation and entrepreneurship, in many cases driven by students from Indigenous communities and families. In 2022, Elizabeth Hoffecker, with eight UVG anthropology majors, set out to identify the most vibrant examples of these collaborative initiatives, which ASPIRE seeks to promote and replicate.Hoffecker’s “innovation ecosystem diagnostic” revealed a cluster of activity centered on UVG’s Altiplano campus in the central highlands, which serves Mayan communities. Hoffecker and two of the anthropology students focused on four examples for a series of case studies, which they are currently preparing for submission to a peer-reviewed journal.“The caliber of their work was so good that it became clear to me that we could collaborate on a paper,” says Hoffecker. “It was my first time publishing with undergraduates.”The researchers’ cases included novel production of traditional thread, and creation of a 3D phytoplankton kit that is being used to educate community members about water pollution in Lake Atitlán, a tourist destination that drives the local economy but is increasingly being affected by toxic algae blooms. Hoffecker singles out a project by Indigenous undergraduates who developed play-based teaching tools for introducing basic mathematical concepts.“These connect to local Mayan ways of understanding and offer a novel, hands-on way to strengthen the math teaching skills of local primary school teachers in Indigenous communities,” says Hoffecker. “They created something that addresses a very immediate need in the community — lack of training.Both of Hoffecker’s undergraduate collaborators are writing theses inspired by these case studies.“My time with Elizabeth allowed me to learn how to conduct research from scratch, ask for help, find solutions, and trust myself,” says Sarmiento García. She finds the ASPIRE approach profoundly appealing. “It is not only ethical, but also deeply committed to applying results to the real lives of the people involved.”“This experience has been incredibly positive, validating my own ability to generate knowledge through research, rather than relying only on established authors to back up my arguments,” says Camila del Cid, a fifth-year anthropology student. “This was empowering, especially as a Latin American researcher, because it emphasized that my perspective and contributions are important.”Hoffecker says this pilot run with UVG undergrads produced “high-quality research that can inform evidence-based decision-making on development issues of top regional priority” — a key goal for ASPIRE. Hoffecker plans to “develop a pathway that other UVG students can follow to conduct similar research.”MIT undergraduate research will continue. “Our students’ activities have been very valuable in Guatemala, so much so that the snow pea, chitosan, and essential oils teams would like to continue working with our students this year,” says Leith.  She anticipates a new round of MIT UROPs for next summer.Youssef, for one, is eager to get to work on refining the snow pea cart. “I like the idea of working outside my comfort zone, thinking about things that seem unsolvable and coming up with a solution to fix some aspect of the problem,” she says. More

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      in Environment

      Solar-powered desalination system requires no extra batteries

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      MIT engineers have built a new desalination system that runs with the rhythms of the sun.The solar-powered system removes salt from water at a pace that closely follows changes in solar energy. As sunlight increases through the day, the system ramps up its desalting process and automatically adjusts to any sudden variation in sunlight, for example by dialing down in response to a passing cloud or revving up as the skies clear.Because the system can quickly react to subtle changes in sunlight, it maximizes the utility of solar energy, producing large quantities of clean water despite variations in sunlight throughout the day. In contrast to other solar-driven desalination designs, the MIT system requires no extra batteries for energy storage, nor a supplemental power supply, such as from the grid.The engineers tested a community-scale prototype on groundwater wells in New Mexico over six months, working in variable weather conditions and water types. The system harnessed on average over 94 percent of the electrical energy generated from the system’s solar panels to produce up to 5,000 liters of water per day despite large swings in weather and available sunlight.“Conventional desalination technologies require steady power and need battery storage to smooth out a variable power source like solar. By continually varying power consumption in sync with the sun, our technology directly and efficiently uses solar power to make water,” says Amos Winter, the Germeshausen Professor of Mechanical Engineering and director of the K. Lisa Yang Global Engineering and Research (GEAR) Center at MIT. “Being able to make drinking water with renewables, without requiring battery storage, is a massive grand challenge. And we’ve done it.”The system is geared toward desalinating brackish groundwater — a salty source of water that is found in underground reservoirs and is more prevalent than fresh groundwater resources. The researchers see brackish groundwater as a huge untapped source of potential drinking water, particularly as reserves of fresh water are stressed in parts of the world. They envision that the new renewable, battery-free system could provide much-needed drinking water at low costs, especially for inland communities where access to seawater and grid power are limited.“The majority of the population actually lives far enough from the coast, that seawater desalination could never reach them. They consequently rely heavily on groundwater, especially in remote, low-income regions. And unfortunately, this groundwater is becoming more and more saline due to climate change,” says Jonathan Bessette, MIT PhD student in mechanical engineering. “This technology could bring sustainable, affordable clean water to underreached places around the world.”The researchers report details the new system in a paper appearing today in Nature Water. The study’s co-authors are Bessette, Winter, and staff engineer Shane Pratt.Pump and flowThe new system builds on a previous design, which Winter and his colleagues, including former MIT postdoc Wei He, reported earlier this year. That system aimed to desalinate water through “flexible batch electrodialysis.”Electrodialysis and reverse osmosis are two of the main methods used to desalinate brackish groundwater. With reverse osmosis, pressure is used to pump salty water through a membrane and filter out salts. Electrodialysis uses an electric field to draw out salt ions as water is pumped through a stack of ion-exchange membranes.Scientists have looked to power both methods with renewable sources. But this has been especially challenging for reverse osmosis systems, which traditionally run at a steady power level that’s incompatible with naturally variable energy sources such as the sun.Winter, He, and their colleagues focused on electrodialysis, seeking ways to make a more flexible, “time-variant” system that would be responsive to variations in renewable, solar power.In their previous design, the team built an electrodialysis system consisting of water pumps, an ion-exchange membrane stack, and a solar panel array. The innovation in this system was a model-based control system that used sensor readings from every part of the system to predict the optimal rate at which to pump water through the stack and the voltage that should be applied to the stack to maximize the amount of salt drawn out of the water.When the team tested this system in the field, it was able to vary its water production with the sun’s natural variations. On average, the system directly used 77 percent of the available electrical energy produced by the solar panels, which the team estimated was 91 percent more than traditionally designed solar-powered electrodialysis systems.Still, the researchers felt they could do better.“We could only calculate every three minutes, and in that time, a cloud could literally come by and block the sun,” Winter says. “The system could be saying, ‘I need to run at this high power.’ But some of that power has suddenly dropped because there’s now less sunlight. So, we had to make up that power with extra batteries.”Solar commandsIn their latest work, the researchers looked to eliminate the need for batteries, by shaving the system’s response time to a fraction of a second. The new system is able to update its desalination rate, three to five times per second. The faster response time enables the system to adjust to changes in sunlight throughout the day, without having to make up any lag in power with additional power supplies.The key to the nimbler desalting is a simpler control strategy, devised by Bessette and Pratt. The new strategy is one of “flow-commanded current control,” in which the system first senses the amount of solar power that is being produced by the system’s solar panels. If the panels are generating more power than the system is using, the controller automatically “commands” the system to dial up its pumping, pushing more water through the electrodialysis stacks. Simultaneously, the system diverts some of the additional solar power by increasing the electrical current delivered to the stack, to drive more salt out of the faster-flowing water.“Let’s say the sun is rising every few seconds,” Winter explains. “So, three times a second, we’re looking at the solar panels and saying, ‘Oh, we have more power — let’s bump up our flow rate and current a little bit.’ When we look again and see there’s still more excess power, we’ll up it again. As we do that, we’re able to closely match our consumed power with available solar power really accurately, throughout the day. And the quicker we loop this, the less battery buffering we need.”The engineers incorporated the new control strategy into a fully automated system that they sized to desalinate brackish groundwater at a daily volume that would be enough to supply a small community of about 3,000 people. They operated the system for six months on several wells at the Brackish Groundwater National Desalination Research Facility in Alamogordo, New Mexico. Throughout the trial, the prototype operated under a wide range of solar conditions, harnessing over 94 percent of the solar panel’s electrical energy, on average, to directly power desalination.“Compared to how you would traditionally design a solar desal system, we cut our required battery capacity by almost 100 percent,” Winter says.The engineers plan to further test and scale up the system in hopes of supplying larger communities, and even whole municipalities, with low-cost, fully sun-driven drinking water.“While this is a major step forward, we’re still working diligently to continue developing lower cost, more sustainable desalination methods,” Bessette says.“Our focus now is on testing, maximizing reliability, and building out a product line that can provide desalinated water using renewables to multiple markets around the world,” Pratt adds.The team will be launching a company based on their technology in the coming months.This research was supported in part by the National Science Foundation, the Julia Burke Foundation, and the MIT Morningside Academy of Design. This work was additionally supported in-kind by Veolia Water Technologies and Solutions and Xylem Goulds.  More

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      in Environment

      Translating MIT research into real-world results

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      Inventive solutions to some of the world’s most critical problems are being discovered in labs, classrooms, and centers across MIT every day. Many of these solutions move from the lab to the commercial world with the help of over 85 Institute resources that comprise MIT’s robust innovation and entrepreneurship (I&E) ecosystem. The Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) draws on MIT’s wealth of I&E knowledge and experience to help researchers commercialize their breakthrough technologies through the J-WAFS Solutions grant program. By collaborating with I&E programs on campus, J-WAFS prepares MIT researchers for the commercial world, where their novel innovations aim to improve productivity, accessibility, and sustainability of water and food systems, creating economic, environmental, and societal benefits along the way.The J-WAFS Solutions program launched in 2015 with support from Community Jameel, an international organization that advances science and learning for communities to thrive. Since 2015, J-WAFS Solutions has supported 19 projects with one-year grants of up to $150,000, with some projects receiving renewal grants for a second year of support. Solutions projects all address challenges related to water or food. Modeled after the esteemed grant program of MIT’s Deshpande Center for Technological Innovation, and initially administered by Deshpande Center staff, the J-WAFS Solutions program follows a similar approach by supporting projects that have already completed the basic research and proof-of-concept phases. With technologies that are one to three years away from commercialization, grantees work on identifying their potential markets and learn to focus on how their technology can meet the needs of future customers.“Ingenuity thrives at MIT, driving inventions that can be translated into real-world applications for widespread adoption, implantation, and use,” says J-WAFS Director Professor John H. Lienhard V. “But successful commercialization of MIT technology requires engineers to focus on many challenges beyond making the technology work. MIT’s I&E network offers a variety of programs that help researchers develop technology readiness, investigate markets, conduct customer discovery, and initiate product design and development,” Lienhard adds. “With this strong I&E framework, many J-WAFS Solutions teams have established startup companies by the completion of the grant. J-WAFS-supported technologies have had powerful, positive effects on human welfare. Together, the J-WAFS Solutions program and MIT’s I&E ecosystem demonstrate how academic research can evolve into business innovations that make a better world,” Lienhard says.Creating I&E collaborationsIn addition to support for furthering research, J-WAFS Solutions grants allow faculty, students, postdocs, and research staff to learn the fundamentals of how to transform their work into commercial products and companies. As part of the grant requirements, researchers must interact with mentors through MIT Venture Mentoring Service (VMS). VMS connects MIT entrepreneurs with teams of carefully selected professionals who provide free and confidential mentorship, guidance, and other services to help advance ideas into for-profit, for-benefit, or nonprofit ventures. Since 2000, VMS has mentored over 4,600 MIT entrepreneurs across all industries, through a dynamic and accomplished group of nearly 200 mentors who volunteer their time so that others may succeed. The mentors provide impartial and unbiased advice to members of the MIT community, including MIT alumni in the Boston area. J-WAFS Solutions teams have been guided by 21 mentors from numerous companies and nonprofits. Mentors often attend project events and progress meetings throughout the grant period.“Working with VMS has provided me and my organization with a valuable sounding board for a range of topics, big and small,” says Eric Verploegen PhD ’08, former research engineer in MIT’s D-Lab and founder of J-WAFS spinout CoolVeg. Along with professors Leon Glicksman and Daniel Frey, Verploegen received a J-WAFS Solutions grant in 2021 to commercialize cold-storage chambers that use evaporative cooling to help farmers preserve fruits and vegetables in rural off-grid communities. Verploegen started CoolVeg in 2022 to increase access and adoption of open-source, evaporative cooling technologies through collaborations with businesses, research institutions, nongovernmental organizations, and government agencies. “Working as a solo founder at my nonprofit venture, it is always great to have avenues to get feedback on communications approaches, overall strategy, and operational issues that my mentors have experience with,” Verploegen says. Three years after the initial Solutions grant, one of the VMS mentors assigned to the evaporative cooling team still acts as a mentor to Verploegen today.Another Solutions grant requirement is for teams to participate in the Spark program — a free, three-week course that provides an entry point for researchers to explore the potential value of their innovation. Spark is part of the National Science Foundation’s (NSF) Innovation Corps (I-Corps), which is an “immersive, entrepreneurial training program that facilitates the transformation of invention to impact.” In 2018, MIT received an award from the NSF, establishing the New England Regional Innovation Corps Node (NE I-Corps) to deliver I-Corps training to participants across New England. Trainings are open to researchers, engineers, scientists, and others who want to engage in a customer discovery process for their technology. Offered regularly throughout the year, the Spark course helps participants identify markets and explore customer needs in order to understand how their technologies can be positioned competitively in their target markets. They learn to assess barriers to adoption, as well as potential regulatory issues or other challenges to commercialization. NE-I-Corps reports that since its start, over 1,200 researchers from MIT have completed the program and have gone on to launch 175 ventures, raising over $3.3 billion in funding from grants and investors, and creating over 1,800 jobs.Constantinos Katsimpouras, a research scientist in the Department of Chemical Engineering, went through the NE I-Corps Spark program to better understand the customer base for a technology he developed with professors Gregory Stephanopoulos and Anthony Sinskey. The group received a J-WAFS Solutions grant in 2021 for their microbial platform that converts food waste from the dairy industry into valuable products. “As a scientist with no prior experience in entrepreneurship, the program introduced me to important concepts and tools for conducting customer interviews and adopting a new mindset,” notes Katsimpouras. “Most importantly, it encouraged me to get out of the building and engage in interviews with potential customers and stakeholders, providing me with invaluable insights and a deeper understanding of my industry,” he adds. These interviews also helped connect the team with companies willing to provide resources to test and improve their technology — a critical step to the scale-up of any lab invention.In the case of Professor Cem Tasan’s research group in the Department of Materials Science and Engineering, the I-Corps program led them to the J-WAFS Solutions grant, instead of the other way around. Tasan is currently working with postdoc Onur Guvenc on a J-WAFS Solutions project to manufacture formable sheet metal by consolidating steel scrap without melting, thereby reducing water use compared to traditional steel processing. Before applying for the Solutions grant, Guvenc took part in NE I-Corps. Like Katsimpouras, Guvenc benefited from the interaction with industry. “This program required me to step out of the lab and engage with potential customers, allowing me to learn about their immediate challenges and test my initial assumptions about the market,” Guvenc recalls. “My interviews with industry professionals also made me aware of the connection between water consumption and steelmaking processes, which ultimately led to the J-WAFS 2023 Solutions Grant,” says Guvenc.After completing the Spark program, participants may be eligible to apply for the Fusion program, which provides microgrants of up to $1,500 to conduct further customer discovery. The Fusion program is self-paced, requiring teams to conduct 12 additional customer interviews and craft a final presentation summarizing their key learnings. Professor Patrick Doyle’s J-WAFS Solutions team completed the Spark and Fusion programs at MIT. Most recently, their team was accepted to join the NSF I-Corps National program with a $50,000 award. The intensive program requires teams to complete an additional 100 customer discovery interviews over seven weeks. Located in the Department of Chemical Engineering, the Doyle lab is working on a sustainable microparticle hydrogel system to rapidly remove micropollutants from water. The team’s focus has expanded to higher value purifications in amino acid and biopharmaceutical manufacturing applications. Devashish Gokhale PhD ’24 worked with Doyle on much of the underlying science.“Our platform technology could potentially be used for selective separations in very diverse market segments, ranging from individual consumers to large industries and government bodies with varied use-cases,” Gokhale explains. He goes on to say, “The I-Corps Spark program added significant value by providing me with an effective framework to approach this problem … I was assigned a mentor who provided critical feedback, teaching me how to formulate effective questions and identify promising opportunities.” Gokhale says that by the end of Spark, the team was able to identify the best target markets for their products. He also says that the program provided valuable seminars on topics like intellectual property, which was helpful in subsequent discussions the team had with MIT’s Technology Licensing Office.Another member of Doyle’s team, Arjav Shah, a recent PhD from MIT’s Department of Chemical Engineering and a current MBA candidate at the MIT Sloan School of Management, is spearheading the team’s commercialization plans. Shah attended Fusion last fall and hopes to lead efforts to incorporate a startup company called hydroGel.  “I admire the hypothesis-driven approach of the I-Corps program,” says Shah. “It has enabled us to identify our customers’ biggest pain points, which will hopefully lead us to finding a product-market fit.” He adds “based on our learnings from the program, we have been able to pivot to impact-driven, higher-value applications in the food processing and biopharmaceutical industries.” Postdoc Luca Mazzaferro will lead the technical team at hydroGel alongside Shah.In a different project, Qinmin Zheng, a postdoc in the Department of Civil and Environmental Engineering, is working with Professor Andrew Whittle and Lecturer Fábio Duarte. Zheng plans to take the Fusion course this fall to advance their J-WAFS Solutions project that aims to commercialize a novel sensor to quantify the relative abundance of major algal species and provide early detection of harmful algal blooms. After completing Spark, Zheng says he’s “excited to participate in the Fusion program, and potentially the National I-Corps program, to further explore market opportunities and minimize risks in our future product development.”Economic and societal benefitsCommercializing technologies developed at MIT is one of the ways J-WAFS helps ensure that MIT research advances will have real-world impacts in water and food systems. Since its inception, the J-WAFS Solutions program has awarded 28 grants (including renewals), which have supported 19 projects that address a wide range of global water and food challenges. The program has distributed over $4 million to 24 professors, 11 research staff, 15 postdocs, and 30 students across MIT. Nearly half of all J-WAFS Solutions projects have resulted in spinout companies or commercialized products, including eight companies to date plus two open-source technologies.Nona Technologies is an example of a J-WAFS spinout that is helping the world by developing new approaches to produce freshwater for drinking. Desalination — the process of removing salts from seawater — typically requires a large-scale technology called reverse osmosis. But Nona created a desalination device that can work in remote off-grid locations. By separating salt and bacteria from water using electric current through a process called ion concentration polarization (ICP), their technology also reduces overall energy consumption. The novel method was developed by Jongyoon Han, professor of electrical engineering and biological engineering, and research scientist Junghyo Yoon. Along with Bruce Crawford, a Sloan MBA alum, Han and Yoon created Nona Technologies to bring their lightweight, energy-efficient desalination technology to the market.“My feeling early on was that once you have technology, commercialization will take care of itself,” admits Crawford. The team completed both the Spark and Fusion programs and quickly realized that much more work would be required. “Even in our first 24 interviews, we learned that the two first markets we envisioned would not be viable in the near term, and we also got our first hints at the beachhead we ultimately selected,” says Crawford. Nona Technologies has since won MIT’s $100K Entrepreneurship Competition, received media attention from outlets like Newsweek and Fortune, and hired a team that continues to further the technology for deployment in resource-limited areas where clean drinking water may be scarce. Food-borne diseases sicken millions of people worldwide each year, but J-WAFS researchers are addressing this issue by integrating molecular engineering, nanotechnology, and artificial intelligence to revolutionize food pathogen testing. Professors Tim Swager and Alexander Klibanov, of the Department of Chemistry, were awarded one of the first J-WAFS Solutions grants for their sensor that targets food safety pathogens. The sensor uses specialized droplets that behave like a dynamic lens, changing in the presence of target bacteria in order to detect dangerous bacterial contamination in food. In 2018, Swager launched Xibus Systems Inc. to bring the sensor to market and advance food safety for greater public health, sustainability, and economic security.“Our involvement with the J-WAFS Solutions Program has been vital,” says Swager. “It has provided us with a bridge between the academic world and the business world and allowed us to perform more detailed work to create a usable application,” he adds. In 2022, Xibus developed a product called XiSafe, which enables the detection of contaminants like salmonella and listeria faster and with higher sensitivity than other food testing products. The innovation could save food processors billions of dollars worldwide and prevent thousands of food-borne fatalities annually.J-WAFS Solutions companies have raised nearly $66 million in venture capital and other funding. Just this past June, J-WAFS spinout SiTration announced that it raised an $11.8 million seed round. Jeffrey Grossman, a professor in MIT’s Department of Materials Science and Engineering, was another early J-WAFS Solutions grantee for his work on low-cost energy-efficient filters for desalination. The project enabled the development of nanoporous membranes and resulted in two spinout companies, Via Separations and SiTration. SiTration was co-founded by Brendan Smith PhD ’18, who was a part of the original J-WAFS team. Smith is CEO of the company and has overseen the advancement of the membrane technology, which has gone on to reduce cost and resource consumption in industrial wastewater treatment, advanced manufacturing, and resource extraction of materials such as lithium, cobalt, and nickel from recycled electric vehicle batteries. The company also recently announced that it is working with the mining company Rio Tinto to handle harmful wastewater generated at mines.But it’s not just J-WAFS spinout companies that are producing real-world results. Products like the ECC Vial — a portable, low-cost method for E. coli detection in water — have been brought to the market and helped thousands of people. The test kit was developed by MIT D-Lab Lecturer Susan Murcott and Professor Jeffrey Ravel of the MIT History Section. The duo received a J-WAFS Solutions grant in 2018 to promote safely managed drinking water and improved public health in Nepal, where it is difficult to identify which wells are contaminated by E. coli. By the end of their grant period, the team had manufactured approximately 3,200 units, of which 2,350 were distributed — enough to help 12,000 people in Nepal. The researchers also trained local Nepalese on best manufacturing practices.“It’s very important, in my life experience, to follow your dream and to serve others,” says Murcott. Economic success is important to the health of any venture, whether it’s a company or a product, but equally important is the social impact — a philosophy that J-WAFS research strives to uphold. “Do something because it’s worth doing and because it changes people’s lives and saves lives,” Murcott adds.As J-WAFS prepares to celebrate its 10th anniversary this year, we look forward to continued collaboration with MIT’s many I&E programs to advance knowledge and develop solutions that will have tangible effects on the world’s water and food systems.Learn more about the J-WAFS Solutions program and about innovation and entrepreneurship at MIT. More

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      New filtration material could remove long-lasting chemicals from water

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      Water contamination by the chemicals used in today’s technology is a rapidly growing problem globally. A recent study by the U.S. Centers for Disease Control found that 98 percent of people tested had detectable levels of PFAS, a family of particularly long-lasting compounds also known as “forever chemicals,” in their bloodstream.A new filtration material developed by researchers at MIT might provide a nature-based solution to this stubborn contamination issue. The material, based on natural silk and cellulose, can remove a wide variety of these persistent chemicals as well as heavy metals. And, its antimicrobial properties can help keep the filters from fouling.The findings are described in the journal ACS Nano, in a paper by MIT postdoc Yilin Zhang, professor of civil and environmental engineering Benedetto Marelli, and four others from MIT.PFAS chemicals are present in a wide range of products, including cosmetics, food packaging, water-resistant clothing, firefighting foams, and antistick coating for cookware. A recent study identified 57,000 sites contaminated by these chemicals in the U.S. alone. The U.S. Environmental Protection Agency has estimated that PFAS remediation will cost $1.5 billion per year, in order to meet new regulations that call for limiting the compound to less than 7 parts per trillion in drinking water.Contamination by PFAS and similar compounds “is actually a very big deal, and current solutions may only partially resolve this problem very efficiently or economically,” Zhang says. “That’s why we came up with this protein and cellulose-based, fully natural solution,” he says.“We came to the project by chance,” Marelli notes. The initial technology that made the filtration material possible was developed by his group for a completely unrelated purpose — as a way to make a labelling system to counter the spread of counterfeit seeds, which are often of inferior quality. His team devised a way of processing silk proteins into uniform nanoscale crystals, or “nanofibrils,” through an environmentally benign, water-based drop-casting method at room temperature.Zhang suggested that their new nanofibrillar material might be effective at filtering contaminants, but initial attempts with the silk nanofibrils alone didn’t work. The team decided to try adding another material: cellulose, which is abundantly available and can be obtained from agricultural wood pulp waste. The researchers used a self-assembly method in which the silk fibroin protein is suspended in water and then templated into nanofibrils by inserting “seeds” of cellulose nanocrystals. This causes the previously disordered silk molecules to line up together along the seeds, forming the basis of a hybrid material with distinct new properties.By integrating cellulose into the silk-based fibrils that could be formed into a thin membrane, and then tuning the electrical charge of the cellulose, the researchers produced a material that was highly effective at removing contaminants in lab tests.

      By integrating cellulose into the silk-based fibrils that could be formed into a thin membrane, and then tuning the electrical charge of the cellulose, the researchers produced a material that was highly effective at removing contaminants in lab tests. Pictured is an example of the filter.

      Image: Courtesy of the researchers

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      The electrical charge of the cellulose, they found, also gave it strong antimicrobial properties. This is a significant advantage, since one of the primary causes of failure in filtration membranes is fouling by bacteria and fungi. The antimicrobial properties of this material should greatly reduce that fouling issue, the researchers say.“These materials can really compete with the current standard materials in water filtration when it comes to extracting metal ions and these emerging contaminants, and they can also outperform some of them currently,” Marelli says. In lab tests, the materials were able to extract orders of magnitude more of the contaminants from water than the currently used standard materials, activated carbon or granular activated carbon.While the new work serves as a proof of principle, Marelli says, the team plans to continue working on improving the material, especially in terms of durability and availability of source materials. While the silk proteins used can be available as a byproduct of the silk textile industry, if this material were to be scaled up to address the global needs for water filtration, the supply might be insufficient. Also, alternative protein materials may turn out to perform the same function at lower cost.Initially, the material would likely be used as a point-of-use filter, something that could be attached to a kitchen faucet, Zhang says. Eventually, it could be scaled up to provide filtration for municipal water supplies, but only after testing demonstrates that this would not pose any risk of introducing any contamination into the water supply. But one big advantage of the material, he says, is that both the silk and the cellulose constituents are considered food-grade substances, so any contamination is unlikely.“Most of the normal materials available today are focusing on one class of contaminants or solving single problems,” Zhang says. “I think we are among the first to address all of these simultaneously.”“What I love about this approach is that it is using only naturally grown materials like silk and cellulose to fight pollution,” says Hannes Schniepp, professor of applied science at the College of William and Mary, who was not associated with this work. “In competing approaches, synthetic materials are used — which usually require only more chemistry to fight some of the adverse outcomes that chemistry has produced. [This work] breaks this cycle! … If this can be mass-produced in an economically viable way, this could really have a major impact.”The research team included MIT postdocs Hui Sun and Meng Li, graduate student Maxwell Kalinowski, and recent graduate Yunteng Cao PhD ’22, now a postdoc at Yale University. The work was supported by the U.S. Office of Naval Research, the U.S. National Science Foundation, and the Singapore-MIT Alliance for Research and Technology. More

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      MIT School of Science launches Center for Sustainability Science and Strategy

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      The MIT School of Science is launching a center to advance knowledge and computational capabilities in the field of sustainability science, and support decision-makers in government, industry, and civil society to achieve sustainable development goals. Aligned with the Climate Project at MIT, researchers at the MIT Center for Sustainability Science and Strategy will develop and apply expertise from across the Institute to improve understanding of sustainability challenges, and thereby provide actionable knowledge and insight to inform strategies for improving human well-being for current and future generations.Noelle Selin, professor at MIT’s Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences, will serve as the center’s inaugural faculty director. C. Adam Schlosser and Sergey Paltsev, senior research scientists at MIT, will serve as deputy directors, with Anne Slinn as executive director.Incorporating and succeeding both the Center for Global Change Science and Joint Program on the Science and Policy of Global Change while adding new capabilities, the center aims to produce leading-edge research to help guide societal transitions toward a more sustainable future. Drawing on the long history of MIT’s efforts to address global change and its integrated environmental and human dimensions, the center is well-positioned to lead burgeoning global efforts to advance the field of sustainability science, which seeks to understand nature-society systems in their full complexity. This understanding is designed to be relevant and actionable for decision-makers in government, industry, and civil society in their efforts to develop viable pathways to improve quality of life for multiple stakeholders.“As critical challenges such as climate, health, energy, and food security increasingly affect people’s lives around the world, decision-makers need a better understanding of the earth in its full complexity — and that includes people, technologies, and institutions as well as environmental processes,” says Selin. “Better knowledge of these systems and how they interact can lead to more effective strategies that avoid unintended consequences and ensure an improved quality of life for all.”    Advancing knowledge, computational capability, and decision supportTo produce more precise and comprehensive knowledge of sustainability challenges and guide decision-makers to formulate more effective strategies, the center has set the following goals:Advance fundamental understanding of the complex interconnected physical and socio-economic systems that affect human well-being. As new policies and technologies are developed amid climate and other global changes, they interact with environmental processes and institutions in ways that can alter the earth’s critical life-support systems. Fundamental mechanisms that determine many of these systems’ behaviors, including those related to interacting climate, water, food, and socio-economic systems, remain largely unknown and poorly quantified. Better understanding can help society mitigate the risks of abrupt changes and “tipping points” in these systems.Develop, establish and disseminate new computational tools toward better understanding earth systems, including both environmental and human dimensions. The center’s work will integrate modeling and data analysis across disciplines in an era of increasing volumes of observational data. MIT multi-system models and data products will provide robust information to inform decision-making and shape the next generation of sustainability science and strategy.Produce actionable science that supports equity and justice within and across generations. The center’s research will be designed to inform action associated with measurable outcomes aligned with supporting human well-being across generations. This requires engaging a broad range of stakeholders, including not only nations and companies, but also nongovernmental organizations and communities that take action to promote sustainable development — with special attention to those who have historically borne the brunt of environmental injustice.“The center’s work will advance fundamental understanding in sustainability science, leverage leading-edge computing and data, and promote engagement and impact,” says Selin. “Our researchers will help lead scientists and strategists across the globe who share MIT’s commitment to mobilizing knowledge to inform action toward a more sustainable world.”Building a better world at MITBuilding on existing MIT capabilities in sustainability, science, and strategy, the center aims to: focus research, education, and outreach under a theme that reflects a comprehensive state of the field and international research directions, fostering a dynamic community of students, researchers, and faculty;raise the visibility of sustainability science at MIT, emphasizing links between science and action, in the context of existing Institute goals and other efforts on climate and sustainability, and in a way that reflects the vital contributions of a range of natural and social science disciplines to understanding human-environment systems; andre-emphasize MIT’s long-standing expertise in integrated systems modeling while leveraging the Institute’s concurrent leading-edge strengths in data and computing, establishing leadership that harnesses recent innovations, including those in machine learning and artificial intelligence, toward addressing the science challenges of global change and sustainability.“The Center for Sustainability Science and Strategy will provide the necessary synergy for our MIT researchers to develop, deploy, and scale up serious solutions to climate change and other critical sustainability challenges,” says Nergis Mavalvala, the Curtis and Kathleen Marble Professor of Astrophysics and dean of the MIT School of Science. “With Professor Selin at its helm, the center will also ensure that these solutions are created in concert with the people who are directly affected now and in the future.”The center builds on more than three decades of achievements by the Center for Global Change Science and the Joint Program on the Science and Policy of Global Change, both of which were directed or co-directed by professor of atmospheric science Ronald Prinn. More

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      in Environment

      Microscopic defects in ice influence how massive glaciers flow, study shows

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      As they seep and calve into the sea, melting glaciers and ice sheets are raising global water levels at unprecedented rates. To predict and prepare for future sea-level rise, scientists need a better understanding of how fast glaciers melt and what influences their flow.Now, a study by MIT scientists offers a new picture of glacier flow, based on microscopic deformation in the ice. The results show that a glacier’s flow depends strongly on how microscopic defects move through the ice.The researchers found they could estimate a glacier’s flow based on whether the ice is prone to microscopic defects of one kind versus another. They used this relationship between micro- and macro-scale deformation to develop a new model for how glaciers flow. With the new model, they mapped the flow of ice in locations across the Antarctic Ice Sheet.Contrary to conventional wisdom, they found, the ice sheet is not a monolith but instead is more varied in where and how it flows in response to warming-driven stresses. The study “dramatically alters the climate conditions under which marine ice sheets may become unstable and drive rapid rates of sea-level rise,” the researchers write in their paper.“This study really shows the effect of microscale processes on macroscale behavior,” says Meghana Ranganathan PhD ’22, who led the study as a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS) and is now a postdoc at Georgia Tech. “These mechanisms happen at the scale of water molecules and ultimately can affect the stability of the West Antarctic Ice Sheet.”“Broadly speaking, glaciers are accelerating, and there are a lot of variants around that,” adds co-author and EAPS Associate Professor Brent Minchew. “This is the first study that takes a step from the laboratory to the ice sheets and starts evaluating what the stability of ice is in the natural environment. That will ultimately feed into our understanding of the probability of catastrophic sea-level rise.”Ranganathan and Minchew’s study appears this week in the Proceedings of the National Academy of Sciences.Micro flowGlacier flow describes the movement of ice from the peak of a glacier, or the center of an ice sheet, down to the edges, where the ice then breaks off and melts into the ocean — a normally slow process that contributes over time to raising the world’s average sea level.In recent years, the oceans have risen at unprecedented rates, driven by global warming and the accelerated melting of glaciers and ice sheets. While the loss of polar ice is known to be a major contributor to sea-level rise, it is also the biggest uncertainty when it comes to making predictions.“Part of it’s a scaling problem,” Ranganathan explains. “A lot of the fundamental mechanisms that cause ice to flow happen at a really small scale that we can’t see. We wanted to pin down exactly what these microphysical processes are that govern ice flow, which hasn’t been represented in models of sea-level change.”The team’s new study builds on previous experiments from the early 2000s by geologists at the University of Minnesota, who studied how small chips of ice deform when physically stressed and compressed. Their work revealed two microscopic mechanisms by which ice can flow: “dislocation creep,” where molecule-sized cracks migrate through the ice, and “grain boundary sliding,” where individual ice crystals slide against each other, causing the boundary between them to move through the ice.The geologists found that ice’s sensitivity to stress, or how likely it is to flow, depends on which of the two mechanisms is dominant. Specifically, ice is more sensitive to stress when microscopic defects occur via dislocation creep rather than grain boundary sliding.Ranganathan and Minchew realized that those findings at the microscopic level could redefine how ice flows at much larger, glacial scales.“Current models for sea-level rise assume a single value for the sensitivity of ice to stress and hold this value constant across an entire ice sheet,” Ranganathan explains. “What these experiments showed was that actually, there’s quite a bit of variability in ice sensitivity, due to which of these mechanisms is at play.”A mapping matchFor their new study, the MIT team took insights from the previous experiments and developed a model to estimate an icy region’s sensitivity to stress, which directly relates to how likely that ice is to flow. The model takes in information such as the ambient temperature, the average size of ice crystals, and the estimated mass of ice in the region, and calculates how much the ice is deforming by dislocation creep versus grain boundary sliding. Depending on which of the two mechanisms is dominant, the model then estimates the region’s sensitivity to stress.The scientists fed into the model actual observations from various locations across the Antarctic Ice Sheet, where others had previously recorded data such as the local height of ice, the size of ice crystals, and the ambient temperature. Based on the model’s estimates, the team generated a map of ice sensitivity to stress across the Antarctic Ice Sheet. When they compared this map to satellite and field measurements taken of the ice sheet over time, they observed a close match, suggesting that the model could be used to accurately predict how glaciers and ice sheets will flow in the future.“As climate change starts to thin glaciers, that could affect the sensitivity of ice to stress,” Ranganathan says. “The instabilities that we expect in Antarctica could be very different, and we can now capture those differences, using this model.”  More

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      in Security

      Sophia Chen: It’s our duty to make the world better through empathy, patience, and respect

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      Sophia Chen, a fifth-year senior double majoring in mechanical engineering and art and design, learned about MIT D-Lab when she was a Florida middle schooler. She drove with her family from their home in Clearwater to Tampa to an MIT informational open house for prospective students. There, she heard about a moringa seed press that had been developed by D-Lab students. Those students, Kwami Williams ’12 and Emily Cunningham (a cross-registered Harvard University student), went on to found MoringaConnect with a goal of increasing Ghanaian farmer incomes. Over the past 12 years, the company has done just that, sometimes by a factor of 10 or more, by selling to wholesalers and establishing their own line of moringa skin and hair care products, as well as nutritional supplements and teas.“I remember getting chills,” says Sophia. “I was so in awe. MIT had always been my dream college growing up, but hearing this particular story truly cemented that dream. I even talked about D-Lab during my admissions interview. Once I came to MIT, I knew I had to take a D-Lab class — and now, at the end of my five years, I’ve taken four.”Taking four D-Lab classes during her undergraduate years may make Sophia exceptional, though not unusual. Of the nearly 4,000 enrollments in D-Lab classes over the past 22 years, as many as 20 percent took at least two classes, and many take three or more by the time the graduate. For Sophia, her D-Lab classes were a logical progression that both confirmed and expanded her career goals in global medicine.Centering the role of project community partnersSophia’s first D-Lab class was 2.722J / EC.720 (D-Lab: Design). Like all D-Lab classes, D-Lab: Design is project-based and centers the knowledge and contributions of each project’s community partner. Her team worked with a group in Uganda called Safe Water Harvesters on a project aimed at creating a solar-powered atmospheric water harvester using desiccants. They focused on early research and development for the desiccant technology by running tests for vapor absorption. Safe Water Harvesters designed the parameters and goals of the project and collaborated with the students remotely throughout the semester.Safe Water Harvesters’ role in the project was key to the project’s success. “At D-Lab, I learned the importance of understanding that solutions in international development must come from the voices and needs of people whom the intervention is trying to serve,” she says. “Some of the first questions we were taught to ask are ‘what materials and manufacturing processes are available?’ and ‘how is this technology going to be maintained by the community?’”The link between water access and gender inequityElecting to join the water harvesting project in Uganda was no accident. The previous summer, Sophia had interned with a startup targeting the spread of cholera in developing areas by engineering a new type of rapid detection technology that would sample from users’ local water sources. From there, she joined Professor Amos Winter’s Global Engineering and Research (GEAR) Lab as an Undergraduate Research Opportunities Program student and worked on a point-of-use desalination unit for households in India. Taking EC.715 (D-Lab: Water, Sanitation, and Hygiene) was a logical next step for Sophia. “This class was life-changing,” she says. “I was already passionate about clean water access and global resource equity, but I quickly discovered the complexity of WASH not just as an issue of poverty but as an issue of gender.” She joined a project spearheaded by a classmate from Nepal, which aimed to address the social taboos surrounding menstruation among Nepalese schoolgirls.“This class and project helped me realize that water insecurity and gender inequality — especially gender-based violence — ​are highly intertwined,” comments Sophia. This plays out in a variety of ways. Where there is poor sanitation infrastructure in schools, girls often miss classes or drop out altogether when menstruating. And where water is scarce, women and girls often walk miles to collect water to accommodate daily drinking, cooking, and hygiene needs. During this trek, they are vulnerable to assault and the pressure to engage in transactional sex at water access points.“It became clear to me that women are disproportionately affected by water insecurity, and that water is key to understanding women’s empowerment,” comments Sophia, “and that I wanted to keep learning about the field of development and how it intersects with gender!”So, in fall 2023, Sophia took both 11.025/EC.701 (D-Lab: Development) and WGS.277/EC.718 (D-Lab: Gender and Development). In D-Lab: Development, her team worked with Tatirano, a nongovernmental organization in Madagascar, to develop a vapor-condensing chamber for a water desalination system, a prototype they were able to test and iterate in Madagascar at the end of the semester.Getting out into the world through D-Lab fieldwork“Fieldwork with D-Lab is an eye-opening experience that anyone could benefit from,” says Sophia. “It’s easy to get lost in the MIT and tech bubble. But there’s a whole world out there with people who live such different lives than many of us, and we can learn even more from them than we can from our psets.”For Sophia’s D-Lab: Gender and Development class, she worked with the Society Empowerment Project in Kenya, ultimately traveling there during MIT’s Independent Activities Period last January. In Kenya, she worked with her team to run a workshop with teen parents to identify risk factors prior to pregnancy and postpartum challenges, in order to then ideate and develop solutions such as social programs. “Through my fieldwork in Kenya and Madagascar,” says Sophia, “it became clear how important it is to create community-based solutions that are led and maintained by community members. Solutions need community input, leadership, and trust. Ultimately, this is the only way to have long-lasting, high-impact, sustainable change. One of my D-Lab trip leaders said that you cannot import solutions. I hope all engineers recognize the significance of this statement. It is our duty as engineers and scientists to make the world a better place while carrying values of empathy, patience, and respect.”Pursuing passion and purpose at the intersection of medicine, technology, and policyAfter graduation in June, Sophia will be traveling to South Africa through MISTI Africa to help with a clinical trial and community outreach. She then intends to pursue a master’s in global health and apply to medical school, with the goal of working in global health at the intersection of medicine, technology, and policy.“It is no understatement to say that D-Lab has played a central role in helping me discover what I’m passionate about and what my purpose is in life,” she says. “I hope to dedicate my career towards solving global health inequity and gender inequality.” ​ More