Aurelia Butler

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    in Environment

    Using graphene foam to filter toxins from drinking water

    Some kinds of water pollution, such as algal blooms and plastics that foul rivers, lakes, and marine environments, lie in plain sight. But other contaminants are not so readily apparent, which makes their impact potentially more dangerous. Among these invisible substances is uranium. Leaching into water resources from mining operations, nuclear waste sites, or from natural subterranean deposits, the element can now be found flowing out of taps worldwide.

    In the United States alone, “many areas are affected by uranium contamination, including the High Plains and Central Valley aquifers, which supply drinking water to 6 million people,” says Ahmed Sami Helal, a postdoc in the Department of Nuclear Science and Engineering. This contamination poses a near and present danger. “Even small concentrations are bad for human health,” says Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering and professor of materials science and engineering.

    Now, a team led by Li has devised a highly efficient method for removing uranium from drinking water. Applying an electric charge to graphene oxide foam, the researchers can capture uranium in solution, which precipitates out as a condensed solid crystal. The foam may be reused up to seven times without losing its electrochemical properties. “Within hours, our process can purify a large quantity of drinking water below the EPA limit for uranium,” says Li.

    A paper describing this work was published in this week Advanced Materials. The two first co-authors are Helal and Chao Wang, a postdoc at MIT during the study, who is now with the School of Materials Science and Engineering at Tongji University, Shanghai. Researchers from Argonne National Laboratory, Taiwan’s National Chiao Tung University, and the University of Tokyo also participated in the research. The Defense Threat Reduction Agency (U.S. Department of Defense) funded later stages of this work.

    Targeting the contaminant

    The project, launched three years ago, began as an effort to find better approaches to environmental cleanup of heavy metals from mining sites. To date, remediation methods for such metals as chromium, cadmium, arsenic, lead, mercury, radium, and uranium have proven limited and expensive. “These techniques are highly sensitive to organics in water, and are poor at separating out the heavy metal contaminants,” explains Helal. “So they involve long operation times, high capital costs, and at the end of extraction, generate more toxic sludge.”

    To the team, uranium seemed a particularly attractive target. Field testing from the U.S. Geological Service and the Environmental Protection Agency (EPA) has revealed unhealthy levels of uranium moving into reservoirs and aquifers from natural rock sources in the northeastern United States, from ponds and pits storing old nuclear weapons and fuel in places like Hanford, Washington, and from mining activities located in many western states. This kind of contamination is prevalent in many other nations as well. An alarming number of these sites show uranium concentrations close to or above the EPA’s recommended ceiling of 30 parts per billion (ppb) — a level linked to kidney damage, cancer risk, and neurobehavioral changes in humans.

    The critical challenge lay in finding a practical remediation process exclusively sensitive to uranium, capable of extracting it from solution without producing toxic residues. And while earlier research showed that electrically charged carbon fiber could filter uranium from water, the results were partial and imprecise.

    Wang managed to crack these problems — based on her investigation of the behavior of graphene foam used for lithium-sulfur batteries. “The physical performance of this foam was unique because of its ability to attract certain chemical species to its surface,” she says. “I thought the ligands in graphene foam would work well with uranium.”

    Simple, efficient, and clean

    The team set to work transforming graphene foam into the equivalent of a uranium magnet. They learned that by sending an electric charge through the foam, splitting water and releasing hydrogen, they could increase the local pH and induce a chemical change that pulled uranium ions out of solution. The researchers found that the uranium would graft itself onto the foam’s surface, where it formed a never-before-seen crystalline uranium hydroxide. On reversal of the electric charge, the mineral, which resembles fish scales, slipped easily off the foam.

    It took hundreds of tries to get the chemical composition and electrolysis just right. “We kept changing the functional chemical groups to get them to work correctly,” says Helal. “And the foam was initially quite fragile, tending to break into pieces, so we needed to make it stronger and more durable,” says Wang.

    This uranium filtration process is simple, efficient, and clean, according to Li: “Each time it’s used, our foam can capture four times its own weight of uranium, and we can achieve an extraction capacity of 4,000 mg per gram, which is a major improvement over other methods,” he says. “We’ve also made a major breakthrough in reusability, because the foam can go through seven cycles without losing its extraction efficiency.” The graphene foam functions as well in seawater, where it reduces uranium concentrations from 3 parts per million to 19.9 ppb, showing that other ions in the brine do not interfere with filtration.

    The team believes its low-cost, effective device could become a new kind of home water filter, fitting on faucets like those of commercial brands. “Some of these filters already have activated carbon, so maybe we could modify these, add low-voltage electricity to filter uranium,” says Li.

    “The uranium extraction this device achieves is very impressive when compared to existing methods,” says Ho Jin Ryu, associate professor of nuclear and quantum engineering at the Korea Advanced Institute of Science and Technology. Ryu, who was not involved in the research, believes that the demonstration of graphene foam reusability is a “significant advance,” and that “the technology of local pH control to enhance uranium deposition will be impactful because the scientific principle can be applied more generally to heavy metal extraction from polluted water.”

    The researchers have already begun investigating broader applications of their method. “There is a science to this, so we can modify our filters to be selective for other heavy metals such as lead, mercury, and cadmium,” says Li. He notes that radium is another significant danger for locales in the United States and elsewhere that lack resources for reliable drinking water infrastructure.

    “In the future, instead of a passive water filter, we could be using a smart filter powered by clean electricity that turns on electrolytic action, which could extract multiple toxic metals, tell you when to regenerate the filter, and give you quality assurance about the water you’re drinking.” More

  • 138 Shares189 Views

    in Security

    A new way to detect the SARS-CoV-2 Alpha variant in wastewater

    Researchers from the Antimicrobial Resistance (AMR) interdisciplinary research group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, alongside collaborators from Biobot Analytics, Nanyang Technological University (NTU), and MIT, have successfully developed an innovative, open-source molecular detection method that is able to detect and quantify the B.1.1.7 (Alpha) variant of SARS-CoV-2. The breakthrough paves the way for rapid, inexpensive surveillance of other SARS-CoV-2 variants in wastewater.

    As the world continues to battle and contain Covid-19, the recent identification of SARS-CoV-2 variants with higher transmissibility and increased severity has made developing convenient variant tracking methods essential. Currently, identified variants include the B.1.17 (Alpha) variant first identified in the United Kingdom and the B.1.617.2 (Delta) variant first detected in India.

    Wastewater surveillance has emerged as a critical public health tool to safely and efficiently track the SARS-CoV-2 pandemic in a non-intrusive manner, providing complementary information that enables health authorities to acquire actionable community-level information. Most recently, viral fragments of SARS-CoV-2 were detected in housing estates in Singapore through a proactive wastewater surveillance program. This information, alongside surveillance testing, allowed Singapore’s Ministry of Health to swiftly respond, isolate, and conduct swab tests as part of precautionary measures.

    However, detecting variants through wastewater surveillance is less commonplace due to challenges in existing technology. Next-generation sequencing for wastewater surveillance is time-consuming and expensive. Tests also lack the sensitivity required to detect low variant abundances in dilute and mixed wastewater samples due to inconsistent and/or low sequencing coverage.

    The method developed by the researchers is uniquely tailored to address these challenges and expands the utility of wastewater surveillance beyond testing for SARS-CoV-2, toward tracking the spread of SARS-CoV-2 variants of concern.

    Wei Lin Lee, research scientist at SMART AMR and first author on the paper adds, “This is especially important in countries battling SARS-CoV-2 variants. Wastewater surveillance will help find out the true proportion and spread of the variants in the local communities. Our method is sensitive enough to detect variants in highly diluted SARS-CoV-2 concentrations typically seen in wastewater samples, and produces reliable results even for samples which contain multiple SARS-CoV-2 lineages.”

    Led by Janelle Thompson, NTU associate professor, and Eric Alm, MIT professor and SMART AMR principal investigator, the team’s study, “Quantitative SARS-CoV-2 Alpha variant B.1.1.7 Tracking in Wastewater by Allele-Specific RT-qPCR” has been published in Environmental Science & Technology Letters. The research explains the innovative, open-source molecular detection method based on allele-specific RT-qPCR that detects and quantifies the B.1.1.7 (Alpha) variant. The developed assay, tested and validated in wastewater samples across 19 communities in the United States, is able to reliably detect and quantify low levels of the B.1.1.7 (Alpha) variant with low cross-reactivity, and at variant proportions down to 1 percent in a background of mixed SARS-CoV-2 viruses.

    Targeting spike protein mutations that are highly predictive of the B.1.1.7 (Alpha) variant, the method can be implemented using commercially available RT-qPCR protocols. Unlike commercially available products that use proprietary primers and probes for wastewater surveillance, the paper details the open-source method and its development that can be freely used by other organizations and research institutes for their work on wastewater surveillance of SARS-CoV-2 and its variants.

    The breakthrough by the research team in Singapore is currently used by Biobot Analytics, an MIT startup and global leader in wastewater epidemiology headquartered in Cambridge, Massachusetts, serving states and localities throughout the United States. Using the method, Biobot Analytics is able to accept and analyze wastewater samples for the B.1.1.7 (Alpha) variant and plans to add additional variants to its analysis as methods are developed. For example, the SMART AMR team is currently developing specific assays that will be able to detect and quantify the B.1.617.2 (Delta) variant, which has recently been identified as a variant of concern by the World Health Organization.

    “Using the team’s innovative method, we have been able to monitor the B.1.1.7 (Alpha) variant in local populations in the U.S. — empowering leaders with information about Covid-19 trends in their communities and allowing them to make considered recommendations and changes to control measures,” says Mariana Matus PhD ’18, Biobot Analytics CEO and co-founder.

    “This method can be rapidly adapted to detect new variants of concern beyond B.1.1.7,” adds MIT’s Alm. “Our partnership with Biobot Analytics has translated our research into real-world impact beyond the shores of Singapore and aid in the detection of Covid-19 and its variants, serving as an early warning system and guidance for policymakers as they trace infection clusters and consider suitable public health measures.”

    The research is carried out by SMART and supported by the National Research Foundation (NRF) Singapore under its Campus for Research Excellence And Technological Enterprise (CREATE) program.

    SMART was established by MIT in partnership with the National Research Foundation of Singapore (NRF) in 2007. SMART is the first entity in CREATE developed by NRF. SMART serves as an intellectual and innovation hub for research interactions between MIT and Singapore, undertaking cutting-edge research projects in areas of interest to both Singapore and MIT. SMART currently comprises an Innovation Center and five IRGs: AMR, Critical Analytics for Manufacturing Personalized-Medicine, Disruptive and Sustainable Technologies for Agricultural Precision, Future Urban Mobility, and Low Energy Electronic Systems.

    The AMR interdisciplinary research group is a translational research and entrepreneurship program that tackles the growing threat of antimicrobial resistance. By leveraging talent and convergent technologies across Singapore and MIT, AMR aims to develop multiple innovative and disruptive approaches to identify, respond to, and treat drug-resistant microbial infections. Through strong scientific and clinical collaborations, its goal is to provide transformative, holistic solutions for Singapore and the world. More

  • 88 Shares99 Views

    in Environment

    A new approach to preventing human-induced earthquakes

    When humans pump large volumes of fluid into the ground, they can set off potentially damaging earthquakes, depending on the underlying geology. This has been the case in certain oil- and gas-producing regions, where wastewater, often mixed with oil, is disposed of by injecting it back into the ground — a process that has triggered sizable seismic events in recent years.

    Now MIT researchers, working with an interdisciplinary team of scientists from industry and academia, have developed a method to manage such human-induced seismicity, and have demonstrated that the technique successfully reduced the number of earthquakes occurring in an active oil field.

    Their results, appearing today in Nature, could help mitigate earthquakes caused by the oil and gas industry, not just from the injection of wastewater produced with oil, but also that produced from hydraulic fracturing, or “fracking.” The team’s approach could also help prevent quakes from other human activities, such as the filling of water reservoirs and aquifers, and the sequestration of carbon dioxide in deep geologic formations.

    “Triggered seismicity is a problem that goes way beyond producing oil,” says study lead author Bradford Hager, the Cecil and Ida Green Professor of Earth Sciences in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “This is a huge problem for society that will have to be confronted if we are to safely inject carbon dioxide into the subsurface. We demonstrated the kind of study that will be necessary for doing this.”

    The study’s co-authors include Ruben Juanes, professor of civil and environmental engineering at MIT, and collaborators from the University of California at Riverside, the University of Texas at Austin, Harvard University, and Eni, a multinational oil and gas company based in Italy.

    Safe injections

    Both natural and human-induced earthquakes occur along geologic faults, or fractures between two blocks of rock in the Earth’s crust. In stable periods, the rocks on either side of a fault are held in place by the pressures generated by surrounding rocks. But when a large volume of fluid is suddenly injected at high rates, it can upset a fault’s fluid stress balance. In some cases, this sudden injection can lubricate a fault and cause rocks on either side to slip and trigger an earthquake.

    The most common source of such fluid injections is from the oil and gas industry’s disposal of wastewater that is brought up along with oil. Field operators dispose of this water through injection wells that continuously pump the water back into the ground at high pressures.

    “There’s a lot of water produced with the oil, and that water is injected into the ground, which has caused a large number of quakes,” Hager notes. “So, for a while, oil-producing regions in Oklahoma had more magnitude 3 quakes than California, because of all this wastewater that was being injected.”

    In recent years, a similar problem arose in southern Italy, where injection wells on oil fields operated by Eni triggered microseisms in an area where large naturally occurring earthquakes had previously occurred. The company, looking for ways to address the problem, sought consulation from Hager and Juanes, both leading experts in seismicity and subsurface flows.

    “This was an opportunity for us to get access to high-quality seismic data about the subsurface, and learn how to do these injections safely,” Juanes says.

    Seismic blueprint

    The team made use of detailed information, accumulated by the oil company over years of operation in the Val D’Agri oil field, a region of southern Italy that lies in a tectonically active basin. The data included information about the region’s earthquake record, dating back to the 1600s, as well as the structure of rocks and faults, and the state of the subsurface corresponding to the various injection rates of each well.

    This video shows the change in stress on the geologic faults of the Val d’Agri field from 2001 to 2019, as predicted by a new MIT-derived model. Video credit: A. Plesch (Harvard University)

    This video shows small earthquakes occurring on the Costa Molina fault within the Val d’Agri field from 2004 to 2016. Each event is shown for two years fading from an initial bright color to the final dark color. Video credit: A. Plesch (Harvard University)

    The researchers integrated these data into a coupled subsurface flow and geomechanical model, which predicts how the stresses and strains of underground structures evolve as the volume of pore fluid, such as from the injection of water, changes. They connected this model to an earthquake mechanics model in order to translate the changes in underground stress and fluid pressure into a likelihood of triggering earthquakes. They then quantified the rate of earthquakes associated with various rates of water injection, and identified scenarios that were unlikely to trigger large quakes.

    When they ran the models using data from 1993 through 2016, the predictions of seismic activity matched with the earthquake record during this period, validating their approach. They then ran the models forward in time, through the year 2025, to predict the region’s seismic response to three different injection rates: 2,000, 2,500, and 3,000 cubic meters per day. The simulations showed that large earthquakes could be avoided if operators kept injection rates at 2,000 cubic meters per day — a flow rate comparable to a small public fire hydrant.

    Eni field operators implemented the team’s recommended rate at the oil field’s single water injection well over a 30-month period between January 2017 and June 2019. In this time, the team observed only a few tiny seismic events, which coincided with brief periods when operators went above the recommended injection rate.

    “The seismicity in the region has been very low in these two-and-a-half years, with around four quakes of 0.5 magnitude, as opposed to hundreds of quakes, of up to 3 magnitude, that were happening between 2006 and 2016,” Hager says. 

    The results demonstrate that operators can successfully manage earthquakes by adjusting injection rates, based on the underlying geology. Juanes says the team’s modeling approach may help to prevent earthquakes related to other processes, such as the building of water reservoirs and the sequestration of carbon dioxide — as long as there is detailed information about a region’s subsurface.

    “A lot of effort needs to go into understanding the geologic setting,” says Juanes, who notes that, if carbon sequestration were carried out on depleted oil fields, “such reservoirs could have this type of history, seismic information, and geologic interpretation that you could use to build similar models for carbon sequestration. We show it’s at least possible to manage seismicity in an operational setting. And we offer a blueprint for how to do it.”

    This research was supported, in part, by Eni. More

  • 125 Shares199 Views

    in Environment

    What will happen to sediment plumes associated with deep-sea mining?

    In certain parts of the deep ocean, scattered across the seafloor, lie baseball-sized rocks layered with minerals accumulated over millions of years. A region of the central Pacific, called the Clarion Clipperton Fracture Zone (CCFZ), is estimated to contain vast reserves of these rocks, known as “polymetallic nodules,” that are rich in nickel and cobalt  — minerals that are commonly mined on land for the production of lithium-ion batteries in electric vehicles, laptops, and mobile phones.

    As demand for these batteries rises, efforts are moving forward to mine the ocean for these mineral-rich nodules. Such deep-sea-mining schemes propose sending down tractor-sized vehicles to vacuum up nodules and send them to the surface, where a ship would clean them and discharge any unwanted sediment back into the ocean. But the impacts of deep-sea mining — such as the effect of discharged sediment on marine ecosystems and how these impacts compare to traditional land-based mining — are currently unknown.

    Now oceanographers at MIT, the Scripps Institution of Oceanography, and elsewhere have carried out an experiment at sea for the first time to study the turbulent sediment plume that mining vessels would potentially release back into the ocean. Based on their observations, they developed a model that makes realistic predictions of how a sediment plume generated by mining operations would be transported through the ocean.

    The model predicts the size, concentration, and evolution of sediment plumes under various marine and mining conditions. These predictions, the researchers say, can now be used by biologists and environmental regulators to gauge whether and to what extent such plumes would impact surrounding sea life.

    “There is a lot of speculation about [deep-sea-mining’s] environmental impact,” says Thomas Peacock, professor of mechanical engineering at MIT. “Our study is the first of its kind on these midwater plumes, and can be a major contributor to international discussion and the development of regulations over the next two years.”

    The team’s study appears today in Nature Communications: Earth and Environment.

    Peacock’s co-authors at MIT include lead author Carlos Muñoz-Royo, Raphael Ouillon, Chinmay Kulkarni, Patrick Haley, Chris Mirabito, Rohit Supekar, Andrew Rzeznik, Eric Adams, Cindy Wang, and Pierre Lermusiaux, along with collaborators at Scripps, the U.S. Geological Survey, and researchers in Belgium and South Korea.

    Play video

    Out to sea

    Current deep-sea-mining proposals are expected to generate two types of sediment plumes in the ocean: “collector plumes” that vehicles generate on the seafloor as they drive around collecting nodules 4,500 meters below the surface; and possibly “midwater plumes” that are discharged through pipes that descend 1,000 meters or more into the ocean’s aphotic zone, where sunlight rarely penetrates.

    In their new study, Peacock and his colleagues focused on the midwater plume and how the sediment would disperse once discharged from a pipe.

    “The science of the plume dynamics for this scenario is well-founded, and our goal was to clearly establish the dynamic regime for such plumes to properly inform discussions,” says Peacock, who is the director of MIT’s Environmental Dynamics Laboratory.

    To pin down these dynamics, the team went out to sea. In 2018, the researchers boarded the research vessel Sally Ride and set sail 50 kilometers off the coast of Southern California. They brought with them equipment designed to discharge sediment 60 meters below the ocean’s surface.  

    “Using foundational scientific principles from fluid dynamics, we designed the system so that it fully reproduced a commercial-scale plume, without having to go down to 1,000 meters or sail out several days to the middle of the CCFZ,” Peacock says.

    Over one week the team ran a total of six plume experiments, using novel sensors systems such as a Phased Array Doppler Sonar (PADS) and epsilometer developed by Scripps scientists to monitor where the plumes traveled and how they evolved in shape and concentration. The collected data revealed that the sediment, when initially pumped out of a pipe, was a highly turbulent cloud of suspended particles that mixed rapidly with the surrounding ocean water.

    “There was speculation this sediment would form large aggregates in the plume that would settle relatively quickly to the deep ocean,” Peacock says. “But we found the discharge is so turbulent that it breaks the sediment up into its finest constituent pieces, and thereafter it becomes dilute so quickly that the sediment then doesn’t have a chance to stick together.”

    Dilution

    The team had previously developed a model to predict the dynamics of a plume that would be discharged into the ocean. When they fed the experiment’s initial conditions into the model, it produced the same behavior that the team observed at sea, proving the model could accurately predict plume dynamics within the vicinity of the discharge.

    The researchers used these results to provide the correct input for simulations of ocean dynamics to see how far currents would carry the initially released plume.

    “In a commercial operation, the ship is always discharging new sediment. But at the same time the background turbulence of the ocean is always mixing things. So you reach a balance. There’s a natural dilution process that occurs in the ocean that sets the scale of these plumes,” Peacock says. “What is key to determining the extent of the plumes is the strength of the ocean turbulence, the amount of sediment that gets discharged, and the environmental threshold level at which there is impact.”

    Based on their findings, the researchers have developed formulae to calculate the scale of a plume depending on a given environmental threshold. For instance, if regulators determine that a certain concentration of sediments could be detrimental to surrounding sea life, the formula can be used to calculate how far a plume above that concentration would extend, and what volume of ocean water would be impacted over the course of a 20-year nodule mining operation.

    “At the heart of the environmental question surrounding deep-sea mining is the extent of sediment plumes,” Peacock says. “It’s a multiscale problem, from micron-scale sediments, to turbulent flows, to ocean currents over thousands of kilometers. It’s a big jigsaw puzzle, and we are uniquely equipped to work on that problem and provide answers founded in science and data.”

    The team is now working on collector plumes, having recently returned from several weeks at sea to perform the first environmental monitoring of a nodule collector vehicle in the deep ocean in over 40 years.

    This research was supported in part by the MIT Environmental Solutions Initiative, the UC Ship Time Program, the MIT Policy Lab, the 11th Hour Project of the Schmidt Family Foundation, the Benioff Ocean Initiative, and Fundación Bancaria “la Caixa.” More

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    in Environment

    New directions in real estate practice

    Among the courses taught by Siqi Zheng is one identifying how real estate companies can be profitable while building and operating sustainably. Her class, 11.S949 (Sustainable Real Estate), at the MIT Center for Real Estate (CRE) attracts students from throughout the MIT School of Architecture and Planning (SA+P) and MIT Sloan School of Management. Harvard University students also cross-register to attend her course.

    For Zheng, the Samuel Tak Lee Champion Professor of Urban and Real Estate Sustainability, there is a sense of coming full circle.

    “Like these students, I migrated from Harvard to MIT,” Zheng says. “Fifteen years ago, I was one of them. Now I attract Harvard students to my classes.”

    Not only has Zheng progressed from taking courses at CRE while a postdoc at Harvard’s Graduate School of Design to joining the SA+P faculty in 2017, she assumed the role of CRE’s faculty director last summer. Among her goals in this new position is encouraging the center’s culture of sustainability and innovation — the very qualities that brought her to MIT as a student.

    While Zheng’s doctoral studies focused on housing and China’s transition from a centrally planned economy to a market-based system, it was MIT’s focus on urban economics and the “clean air and blue skies” of Cambridge, Massachusetts — in contrast to the polluted air in Beijing — that altered her focus to urban sustainability.

    “Back in 2006, I audited several very good courses at CRE in urban and real estate economics. It opened a window for me to say, ‘I need to study cities instead of just housing — and in a broader way — to understand urban dynamics.’ My research area became the intersection of urban economics and environmental sustainability.”

    Following her postdoc, Zheng returned to Beijing and joined Tsinghua University as an assistant professor and director of its Hang Lung Center for Real Estate.

    Creative urban studies research

    Shortly after arriving at MIT, Zheng founded the China Future City Lab, giving her the opportunity to focus on that country’s rapid economic growth alongside the tension of more sustainable urbanization. Her research shows that Chinese urban households are willing to pay higher real estate prices to live in cities and locations with better environmental quality, and this demand has increased over time. She has also identified a substantial price premium for green buildings, which gives real estate developers a monetary incentive to build energy-efficient structures. Gradually, she says, her research and team expanded along with her interest in other fast-urbanizing countries; she renamed her lab the Sustainable Urbanization Lab.

    Zheng’s research is remarkably varied and prolific, with many collaborators in the United States and overseas. Last year, Zheng was one of six MIT faculty awarded a grant from Harvard Medical School to address the effects of Covid-19. While the other researchers focused on clinical areas, such as vaccine development and diagnostic tools, Zheng’s research explored the role of social distancing in shaping Covid-19’s curve. Currently under review for publication, Zheng’s research compares how people’s sentiment in cities globally responded to the shock of the pandemic and the policies each government mandated to slow the spread of the virus.

    “My overarching goal as a scholar is to build our understanding of the behavioral foundations for urban real estate and environmental actions aimed at sustainable urbanization,” Zheng says. “I look at incentives and how an individual’s behavior gets aggregated into our society and its outcomes. Last year, without a vaccine, we needed to slow the spread of the virus. We had to rely on people in all countries to socially distance. We wanted to understand the interactions between individual sentiments, voluntary behaviors, and government intervention — how they work together, and their outcomes.”

    Currently, Zheng’s team is monitoring social media data to detect behavior changes in the U.S. population before and after vaccination. Their theory is that individuals — once vaccinated against Covid-19 — are happier and take part in riskier behaviors, such as restaurant dining or not wearing a mask.

    “We’ve been monitoring emotional states on social media before the vaccination process began,” she says. “We can measure their emotional status and their activities from their social media posts. People lose their anxiety and fear after vaccination, and they stop taking precautions.”

    Zheng began using social media data as a tool to assess a population’s emotional status several years ago, when she studied emotions in conjunction with levels of air pollution in China. Her paper, “Air pollution lowers Chinese urbanites’ expressed happiness on social media,” appeared in Nature Human Behavior in 2019, and was the journal’s fourth-most popular paper that year.  

    Zheng used the same approach to understand how climate change affects people in China by coupling meteorological conditions with more than 400 million social media posts from 43 million users. Finding that extreme weather worsens emotional expressions on social media allowed the researchers to project the potentially harmful impacts of global warming on subjective well-being.

    CRE’s strategic directions

    Working with CRE Executive Director Professor Kairos Shen, and Associate Director Lisa Thoma, Zheng is mapping out a strategic plan for CRE. One emphasis is expanding interdisciplinary research. She is excited by the new work undertaken by the center’s postdocs and doctoral students, which she sees as fostering synergy with teaching.

    “This is MIT,” says Zheng. “We have excellent teaching — but that’s not enough. We need to have a strong research focus to support teaching because we need to introduce our brilliant students to the field’s frontiers.”

    A parallel strategy is expanding the center’s global perspective. Zheng notes the oft-used expression “location, location, location,” pointing out that, while CRE’s attention has leaned toward the United States and Boston, half of their students are from overseas and the majority of their alumni are based in Asia. As such, she is working to expand collaborations with academic institutions and alumni who are now leaders in the field in Korea, mainland China, Hong Kong, Japan, Singapore, and India. Asia is also the region with the fastest urbanization and real estate growth potential. That’s why Zheng and her colleagues are now developing their “MIT Asia Real Estate Initiative.”

    “I like creating things from scratch,” Zheng says. “The center is small, flexible, and forward-looking, so I have an opportunity to create some new exciting programs and generate new impact.”

    As part of her globalization strategy, Zheng also expects to expand MIT/CRE’s online education offerings. While the center admits only 30 graduate students each year, Zheng sees opportunities for professionals in the global real estate industry to expand their education with an online certificate program. Currently, Zheng is designing six new courses to join the two already online.

    Having begun her new role during the global pandemic, Zheng and her team have only worked remotely. While anxious to get to know her team members “in person and not only over Zoom,” Zheng keeps busy managing various research initiatives, teaching and deepening MIT/CRE’s global connections. She is active on her social media accounts, sharing the Center’s many research activities, industry developments, and student achievements. On weekends however, she posts photos of hiking and exploring with her husband and son.

    “I want to be less intense outside of work; spending time outside surrounded by nature helps me unwind,” she says. More

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    in Environment

    Arlene Fiore appointed first Stone Professor in Earth, Atmospheric and Planetary Sciences

    The MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS) has named atmospheric chemist Arlene Fiore the Peter H. Stone and Paola Malanotte Stone Professor in Earth, Atmospheric and Planetary Sciences. Her chair began on July 1.

    Fiore is the first person to be appointed to this senior position, a full professorship that was generously endowed to EAPS by Professor Emeritus Peter H. Stone and Professor Paola Malanotte-Rizzoli. The couple’s $5 million donation sparked a multi-year campaign to find a suitable candidate to fill this prestigious named chair, intended to attract top scientists and enhance the department’s contributions to research, teaching, and mentorship in atmospheric sciences, physical oceanography, climate sciences, or planetary sciences. 

    The recruitment committee found a winning combination in Fiore, who brings with her 25 years of experience in the geosciences. She specializes in understanding how polluting emissions from anthropogenic and natural sources influence atmospheric chemistry, the climate system, and air pollution on regional to global scales, as well as the drivers of these interactions.

    “I am immensely grateful for the gift by Peter Stone and Paola Malanotte-Rizzoli — long-term colleagues and friends of EAPS — and excited to welcome Arlene into the EAPS community,” says head of EAPS Rob van der Hilst. “Professor Arlene Fiore will bring unique expertise to the EAPS climate program, at a time when MIT is ramping up its efforts to understand the underlying Earth systems and create solutions for mitigation and adaptations to climate change. Combined with her accolades in teaching, mentorship, and organization in support of women and diversity, she will be a huge asset to our research, education, and outreach programs.”

    Fiore comes to EAPS from the Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory of Columbia University, where she breaks her research down into four pillars: air pollution, chemistry-climate connections, trends and variability in atmospheric constituents, and biosphere-atmosphere interactions. She uses a range of models alongside remote sensing and in situ observations to understand tropospheric ozone chemistry, its sensitivity to different sources and sinks including the terrestrial biosphere, on hourly and local scales up to global and decadal dimensions. Fiore and her group also investigate regional meteorology and climate feedbacks due to aerosols versus greenhouse gases, future air pollution responses to climate change, as well as the factors controlling the oxidizing capacity of the atmosphere. As a member of the NASA Health and Air Quality Applied Sciences Team, she partners with air and health management groups to address emerging needs with applications of satellite and other Earth science datasets.

    Since earning her undergraduate and PhD degrees from Harvard University, Fiore held a research scientist position at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory before joining Columbia University. She has since served on numerous boards and earned several awards. Among these are participating on the board of the Atmospheric Sciences and Climate of the National Academy of Sciences, the U.S. CLIVAR Working Group on Large Initial-Condition Earth System Model Ensembles, the American Meteorological Society Statement on Atmospheric Ozone, and the Steering Committee for the IGAC/SPARC Chemistry-Climate Model Initiative. Fiore’s honors include the AGU James R. Holton Junior Scientist Award, Presidential Early Career Award for Scientists and Engineers, which is the highest honor bestowed by the United States government on outstanding scientists and engineers in the early stages of their independent research careers, and AGU’s James B. Macelwane Medal. She is one of six co-founders of the Earth Science Women’s Network, promoting peer mentoring, career development, and equality in the geosciences. 

    “I enjoy studying interactions across realms that have in the past been considered separately (such as the climate system and air quality, urban air pollution and global atmospheric chemistry, the stratosphere and troposphere, terrestrial biosphere and atmosphere),” says Fiore. “Currently, I’m excited about a new research direction that seeks to identify imprints of climate variability on short, sparse observational records of trace gases, so that we can better detect and attribute the influence of human activities on atmospheric composition and climate.”

    Further, at MIT, she looks forward to inspiring the next generation of problem-solvers to understand atmospheric chemistry and climate system data, and equipping them to develop and leverage new computational methods.

    “Fiore is an accomplished researcher in several areas, especially the linking of atmospheric chemistry with climate change phenomena such as changes in rainfall and heat waves,” says Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies at MIT. “EAPS has a lot of strengths in atmospheric chemistry, as well as plenty of depth in climate dynamics and meteorology. Fiore’s conversations with both have been positively electric, and we expect great new linkages to amplify our science impacts after she arrives.”

    Stone and Malanotte-Rizzoli see the greatest challenge of the 21st century to be climate change, making research in the geosciences front and center at this point in history. As such, they endeavored to continue the “tradition of excellence in atmospheric, climate, or planetary sciences,” at MIT. 

    At a reception honoring the generous endowment in 2015, van der Hilst described Stone and Malanotte-Rizzoli as “inspirational leaders,” whose gift not only strengthens the department but also bestows the unique “privilege of having their names forever associated” with EAPS. Both Stone and Malanotte-Rizzoli hold numerous awards and honors for contributions to their fields, and are renowned for their dedication to research and teaching alike. 

    Combined, Stone and Malanotte-Rizzoli have contributed 75 years of active service to the Institute and department. Stone first joined MIT in 1972 as a visiting professor of meteorology, and went on to become department head, director of MIT’s Center for Meteorology and Physical Oceanography, and director of the MIT Climate Modeling Initiative. He was at the forefront of atmospheric and climate dynamics research throughout his career, right up to his retirement in 2007. Malanotte-Rizzoli came to MIT in 1981 as an assistant professor of oceanography. While her physical oceanography interests are varied, she was named professor of physical oceanography in 1992, and spent 12 years directing the graduate-level MIT-Woods Hole Oceanographic Institution Joint Program in Oceanography and Ocean Engineering. Malanotte-Rizzoli has also been a tireless voice in promoting gender equality among faculty at MIT. 

    On the selection of Fiore to the post, Malanotte-Rizzoli says, “We wish to see superb scientists and teachers, not limited to a very specialized scientific sector but who can cross, with equal excellence, disciplinary boundaries and build a new generation of researchers capable to do so. Arlene Fiore is such an example.”

    “We’re very grateful for the chance to bring in an accomplished senior climate person to MIT — especially at this special moment in history when MIT is marshaling its abilities to help address the climate challenge,” says Solomon. “The timing couldn’t be better for strengthening the already considerable climate arsenal in EAPS!” More

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    in Security

    Engineering seeds to resist drought

    As the world continues to warm, many arid regions that already have marginal conditions for agriculture will be increasingly under stress, potentially leading to severe food shortages. Now, researchers at MIT have come up with a promising process for protecting seeds from the stress of water shortage during their crucial germination phase, and even providing the plants with extra nutrition at the same time.

    The process, undergoing continued tests in collaboration with researchers in Morocco, is simple and inexpensive, and could be widely deployed in arid regions, the researchers say. The findings are reported this week in the journal Nature Food, in a paper by MIT professor of civil and environmental engineering Benedetto Marelli, MIT doctoral student Augustine Zvinavashe ’16, and eight others at MIT and at the King Mohammed VI Polytechnic University in Morocco.

    The two-layer coating the team developed is a direct outgrowth of years of research by Marelli and his collaborators in developing seed coatings to confer various benefits. A previous version enabled seeds to resist high salinity in the soil, but the new version is aimed at tackling water shortages.

    “We wanted to make a coating that is specific to tackling drought,” Marelli explains. “Because there is clear evidence that climate change is going to impact the basin of the Mediterranean area,” he says, “we need to develop new technologies that can help to mitigate these changes in the climate patterns that are going to make less water available to agriculture.”

    The new coating, taking inspiration from natural coatings that occur on some seeds such as chia and basil, is engineered to protect the seeds from drying out. It provides a gel-like coating that tenaciously holds onto any moisture that comes along, and envelops the seed with it.

    A second, inner layer of the coating contains preserved microorganisms called rhizobacteria, and some nutrients to help them grow. When exposed to soil and water, the microbes will fix nitrogen into the soil, providing the growing seedling with nutritious fertilizer to help it along.

    “Our idea was to provide multiple functions to the seed coating,” Marelli says, “not only targeting this water jacket, but also targeting the rhizobacteria. This is the real added value to our seed coating, because these are self-replicating microorganisms that can fix nitrogen for the plants, so they can decrease the amount of nitrogen-based fertilizers that are provided, and enrich the soil.”

    Early tests using soil from Moroccan test farms have shown encouraging results, the researchers say, and now field tests of the seeds are underway.

    Ultimately, if the coatings prove their value through further tests, the coatings are simple enough that they could be applied at a local level, even in remote locations in the developing world. “It can be done locally,” Zvinavashe says. “That’s one of the things we were thinking about while we were designing this. The first layer you could dip coat, and then the second layer, you can spray it on. These are very simple processes that farmers could do on their own.” In general, though, Zvinavashe says it would be more economical to do the coatings centrally, in facilities that can more easily preserve and stabilize the nitrogen-fixing bacteria.

    The materials needed for the coatings are readily available and often used in the food industry already, Marelli says. The materials are also fully biodegradable, and some of the compounds themselves can actually be derived from food waste, enabling the eventual possibility of closed-loop systems that continuously recycle their own waste.

    Although the process would add a small amount to the cost of the seeds themselves, Marelli says, it may also produce savings by reducing the need for water and fertilizer. The net balance of costs and benefits remains to be determined through further research.

    Although initial tests using common beans have shown promising results by a variety of measures, including root mass, stem height, chlorophyll content, and other metrics, the team has not yet cultivated a full crop from seeds with the new coating all the way through to harvest, which will be the ultimate test of its value. Assuming that it does improve harvest yields under arid conditions, the next step will be to extend the research to a variety of other important crop seeds, the researchers say.

    “The system is so simple that it can be applied to any seed,” Marelli says. “And we can design the seed coating to respond to different climate patterns.” It might even be possible to tailor coatings to the predicted rainfall of a particular growing season, he says.

    “This is very important work,” says Jason C. White, director of the Connecticut Agricultural Experiment Station and a professor of epidemiology at Yale University, who was not associated with this study. “Maintaining global food security in the coming decades will be among the most significant challenges we face as a species. … This approach fits the description of an important tool in that effort; sustainable, responsive and effective.”

    White says, “Seed coating technologies are not new, but nearly all existing approaches lack versatility or responsiveness.” The new work, he says, is “both novel and innovative,” and “really opens a new avenue of work for responsive seed coatings to mediate tolerance to a range of biotic and abiotic stressors.”

    The team included Julie Laurent, Salma Mouhib, Hui Sun, Henri Manu Effa Fouda, Doyoon Kim, Manal Mhada, and Lamfeddal Kouisni at MIT and at King Mohammad VI Polytechnic University in Ben-Guerir, Morocco. The work was partly supported by the U.S. Office of Naval Research, the National Science Foundation, and the MIT Paul M. Cook Career Development Professorship. More

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    in Environment

    Designing exploratory robots that collect data for marine scientists

    As the Chemistry-Kayak (affectionately known as the ChemYak) swept over the Arctic estuary waters, Victoria Preston was glued to a monitor in a boat nearby, watching as the robot’s sensors captured new data. She and her team had spent weeks preparing for this deployment. With only a week to work on-site, they were making use of the long summer days to collect thousands of observations of a hypothesized chemical anomaly associated with the annual ice-cover retreat.

    The robot moved up and down the stream, using its chemical sensors to detect the composition of the flowing water. Its many measurements revealed a short-lived but massive influx of greenhouse gases in the water during the annual “flushing” of the estuary as ice thawed and receded. For Preston, the experiment’s success was a heartening affirmation of how robotic platforms can be leveraged to help scientists understand the environment in fundamentally new ways.

    Growing up near the Chesapeake Bay in Maryland, Preston learned about the importance of environmental conservation from a young age. She became passionate about how next-generation technologies could be used as tools to make a difference. In 2016, Preston completed her BS in robotics engineering from Olin College of Engineering.

    “My first research project involved creating a drone that could take noninvasive blow samples from exhaling whales,” Preston says. “Some of our work required us to do automatic detection, which would allow the drone to find the blowhole and track it. Overall, it was a great introduction on how to apply fundamental robotics concepts to the real world.”

    Preston’s undergraduate research inspired her to apply for a Fulbright award, which enabled her to work at the Center for Biorobotics in Tallinn, Estonia, for nine months. There, she worked on a variety of robotics projects, such as training a robotic vehicle to map an enclosed underwater space. “I really enjoyed the experience, and it helped shape the research interests I hold today. It also confirmed that grad school was the right next step for me and the work I wanted to do,” she says.

    Uncovering geochemical hotspots

    After her Fulbright ended, Preston began her PhD in aeronautics and astronautics and applied ocean physics and engineering through a joint program between MIT and the Woods Hole Oceanographic Institution. Her co-advisors, Anna Michel and Nicholas Roy, have helped her pursue both theoretical and experimental questions. “I really wanted to have an advisor relationship with a scientist,” she says. “It was a high priority to me to make sure my work would always be a bridge between science and engineering objectives.”

    “Overall, I see robots as a tool for scientists. They take knowledge, explore, bring back datasets. Then scientists do the actual hard work of extracting meaningful information to solve these hard problems,” says Preston.

    The first two years of her research focused on how to deploy robots in environments and process their collected data. She developed algorithms that could allow the robot to move on its own. “My goal was to figure out how to exploit our knowledge of the world and use it to plan optimal sampling trajectories,” says Preston. “This would allow robots to independently navigate to sample in regions of high interest to scientists.”  

    Improving sampling trajectories becomes a major advantage when researchers are working under limited time or budget constraints. Preston was able to deploy her robot in Massachusetts’ Wareham River to detect dissolved methane and other greenhouse gases, byproducts of a wastewater treatment chemical feedstock and natural processes. “Imagine you have a ground seepage of radiation you’re trying to characterize. As the robot moves around, it might get ‘wafts’ of the radiation,” she says.

    “Our algorithm would update to give the robot a new estimate of where the leak might be. The robot responds by moving to that location, collecting more samples and potentially discovering the biggest hotspot or cause for the leak. It also builds a model we can interpret along the way.” This method is a major advancement in efficient sampling in the marine geochemical sciences, since historic strategies meant collecting random bottle samples to be analyzed later in the lab.

    Adapting to real-world requirements

    In the next phase of her work, Preston has been incorporating an important component — time. This will improve explorations that last over several days. “My previous work made this strong assumption that the robot goes in and by the time it’s done, nothing’s different about the environment. In reality this isn’t true, especially for a moving river,” she says. “We’re now trying to figure out how to better model how a space changes over time.”

    This fall, Preston will be traveling on the Scripps Institution of Oceanography research vessel Roger Revelle to the Guaymas Basin the Gulf of California. The research team will be releasing remotely operated and autonomous underwater robots near the bottom of the basin to investigate how hydrothermal plumes move in the water column. Working closely with engineers from the National Deep Submergence Facility, and in collaboration with her advisers and research colleagues at MIT, Preston will be on board, directing the deployment of the devices.

    “I’m looking forward to demonstrating how our algorithmic developments work in practice. It’s also thrilling to be part of a huge, diverse group that’s willing to try this,” she says.

    Preston is just finishing her fourth year of research, and is starting to look toward the future after her PhD. She plans to continue studying marine and other climate-impacted environments. She is driven by our plethora of unexplored questions about the ocean and hopes to use her knowledge to scratch its surface. She’s drawn to the field of computational sustainability, she says, which is based on “the idea is that machine learning, artificial intelligence, and similar tools can and should be applied to solve some of our most pressing challenges, and that these challenges will in turn change how we think about our tools.”

    “This is a really exciting time to be a roboticist who also cares about the environment — and to be a scientist who has access to new tools for research. Maybe I’m a little overly optimistic, but I believe we’re at a pivotal moment for exploration.” More