Evelyn Reynolds

A new system developed by chemical engineers at MIT could provide a way of continuously removing carbon dioxide from a stream of waste gases, or even from the air. The key component is an electrochemically assisted membrane whose permeability to gas can be switched on and off at will, using no moving parts and relatively little energy.
The membranes themselves, made of anodized aluminum oxide, have a honeycomb-like structure made up of hexagonal openings that allow gas molecules to flow in and out when in the open state. However, gas passage can be blocked when a thin layer of metal is electrically deposited to cover the pores of the membrane. The work is described today in the journal Science Advances, in a paper by Professor T. Alan Hatton, postdoc Yayuan Liu, and four others.
This new “gas gating” mechanism could be applied to the continuous removal of carbon dioxide from a range of industrial exhaust streams and from ambient air, the team says. They have built a proof-of-concept device to show this process in action.
The device uses a redox-active carbon-absorbing material, sandwiched between two switchable gas gating membranes. The sorbent and the gating membranes are in close contact with each other and are immersed in an organic electrolyte to provide a medium for zinc ions to shuttle back and forth. These two gating membranes can be opened or closed electrically by switching the polarity of a voltage between them, causing ions of zinc to shuttle from one side to the other. The ions simultaneously block one side, by forming a metallic film over it, while opening the other, by dissolving its film away.
When the sorbent layer is open to the side where the waste gases are flowing by, the material readily soaks up carbon dioxide until it reaches its capacity. The voltage can then be switched to block off the feed side and open up the other side, where a concentrated stream of nearly pure carbon dioxide is released.
By building a system with alternating sections of membrane that operate in opposite phases, the system would allow for continuous operation in a setting such as an industrial scrubber. At any one time, half of the sections would be absorbing the gas while the other half would be releasing it.
“That means that you have a feed stream coming into the system at one end and the product stream leaving from the other in an ostensibly continuous operation,” Hatton says. “This approach avoids many process issues” that would be involved in a traditional multicolumn system, in which adsorption beds alternately need to be shut down, purged, and then regenerated, before being exposed again to the feed gas to begin the next adsorption cycle. In the new system, the purging steps are not required, and the steps all occur cleanly within the unit itself.
The researchers’ key innovation was using electroplating as a way to open and close the pores in a material. Along the way the team had tried a variety of other approaches to reversibly close pores in a membrane material, such as using tiny magnetic spheres that could be positioned to block funnel-shaped openings, but these other methods didn’t prove to be efficient enough. Metal thin films can be particularly effective as gas barriers, and the ultrathin layer used in the new system requires a minimal amount of the zinc material, which is abundant and inexpensive.
“It makes a very uniform coating layer with a minimum amount of materials,” Liu says. One significant advantage of the electroplating method is that once the condition is changed, whether in the open or closed position, it requires no energy input to maintain that state. Energy is only required to switch back again.
Potentially, such a system could make an important contribution toward limiting emissions of greenhouse gases into the atmosphere, and even direct-air capture of carbon dioxide that has already been emitted.
While the team’s initial focus was on the challenge of separating carbon dioxide from a stream of gases, the system could actually be adapted to a wide variety of chemical separation and purification processes, Hatton says.
“We’re pretty excited about the gating mechanism. I think we can use it in a variety of applications, in different configurations,” he says. “Maybe in microfluidic devices, or maybe we could use it to control the gas composition for a chemical reaction. There are many different possibilities.”
The research team included graduate student Chun-Man Chow, postdoc Katherine Phillips, and recent graduates Miao Wang PhD ’20 and Sahag Voskian PhD ’19. This work was supported by ExxonMobil through the MIT Energy Initiative. More

MIT.nano, the Institute’s central, shared-access research facility for nanoscience and nanotechnology, has received the U.S. Green Building Council’s LEED Platinum certification for sustainable practices in new construction.
The Leadership in Energy and Environmental Design (LEED) designation is a performance-based rating system of a building’s environmental attributes associated with its design, construction, operations, and management.
For a leading-edge research center like MIT.nano — which consumes significantly more energy per square foot than a typical office building or traditional laboratory — earning the council’s highest designation of platinum is a remarkable achievement. “MIT.nano’s LEED Platinum certification demonstrates that even the most technically sophisticated buildings can mitigate their environmental impact if sustainability is a priority in the design and construction process,” says Vladimir Bulović, the founding faculty director of MIT.nano and the Fariborz Maseeh Chair in Emerging Technology. “A shared commitment to sustainable principles from the outset made this recognition possible.”
Starting in 2016, MIT made a commitment that all new campus construction and major renovation projects must earn at least LEED Gold certification. MIT.nano joins the Morris and Sophie Chang Building (Building E52) as the second LEED Platinum-certified building on campus. There are 18 total LEED-certified spaces and buildings at MIT.
Recognition is nothing new for the facility, as MIT.nano also received the International Institute for Sustainable Laboratories (I2SL) 2019 “Go Beyond” Award for excellence in sustainability in laboratory and other high-technology facility projects, as well as the R&D World 2019 Lab of the Year Award for excellence in research lab design, planning, and construction, and the AIA New England Honor Award for Design Excellence.
Opportunity beyond the nanoscale
Referred to as the “ship in the bottle” during construction, MIT.nano faced unique challenges due to its location. The building had to rise in the center of a dense urban campus, surrounded on all sides by existing buildings, with very limited access for construction activity and materials. Though constructing the facility was a challenge, the location provides considerable opportunities to connect nanotechnology research to other disciplines and spur new ideas through proximity.
This same mix of challenge and opportunity fueled MIT’s pursuit of its LEED Platinum designation for MIT.nano. Facilities like MIT.nano are resource-intensive: Specialized environments like clean rooms require continuous air exchange, powerful air filtration, precise control and monitoring of temperature and humidity, and other high-energy infrastructure systems to support the diversity of pioneering tools and equipment used.
But the heavy energy requirements of such systems provided a unique opportunity for gains in efficiency. “The energy consumption per square foot of a semiconductor clean room is about an order of magnitude higher than a typical office building. As a result, there is incredible opportunity for innovation during the design process and optimization post occupancy,” says MIT.nano Assistant Director of Infrastructure Nicholas Menounos.
Menounos credits an effort by MIT — including the Department of Facilities and Campus Construction — and the design engineers that went well beyond the typical LEED process. “There was no precedent for a research and development facility of this size, so the team toured around the country, benchmarking against more than 12 peer institutions, to ensure we right-sized the process utilities and HVAC systems,” he says. “Oversizing leads to inefficiencies and undersizing reduces the useful life of the space. This was not a trivial task, and a major reason for the awards.”
Going for platinum
At all levels (certified, silver, gold, and platinum), the LEED certification process is based on a number of points that correlate to sustainability measures. MIT.nano earned points across all seven sections on the LEED scorecard: location and transportation, sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, innovation, and regional priority. The building notched 84 points total, with 80 points or more needed to earn platinum certification.
MIT.nano rated highly in several categories, including optimizing energy performance, water use reduction, indoor environmental quality, and innovation in design. The building’s overall efficiency is supported by extensive indoor environmental controls and monitoring systems. The clean room, for instance, senses user occupancy with motion and particle detectors and adjusts air recirculation rates accordingly.
“MIT.nano is the most technically complex building on campus with thousands of monitoring points spread throughout the facility,” explains Dennis Grimard, managing director at MIT.nano, in a recent MIT News article. “These points help maintain MIT.nano’s sustainability goals by constantly monitoring the building’s health and operation.”
Those controls account for energy efficiency and stability of research as well as the comfort of occupants. With LEED certification also focused on the health, safety, and well-being of people, additional points were earned through the building’s maximization of open space, use of low-emitting materials, and design efforts to increase natural light throughout the building. “One thing you notice as an occupant is this deep natural light, which isn’t common in labs. While this saves building wattage, it also improves comfort and makes the building a pleasure to be in,” says Menounos.
MIT.nano’s LEED strategy was amplified by MIT’s Central Utilities Plant (CUP), which has a symbiotic relationship with the new facility. The CUP has the opportunity to reuse MIT.nano’s reverse osmosis water in its cooling systems, while MIT.nano relies on the CUP’s distributed energy resource for both thermal and electric energy.
Although the LEED Platinum certification may mark the culmination of a scoring procedure for MIT.nano’s design and construction, Menounos says it does not mark the end of sustainability work and optimization within the building. “Sustainability isn’t a moment in time, it’s a process. Now that MIT.nano is operational, we will continually try to find ways we can change and optimize how the building operates,” he says. More

Ride-sharing applications such as Uber and Lyft collect information about a user’s location to improve service and efficiency, but as data breaches and misuse become more frequent, the exposure of user data is of increasing concern. M. Elena Renda, a visiting research scientist in MIT’s JTL Urban Mobility Lab; Francesca Martelli, a researcher at the National Research Council in Pisa, Italy; and Jinhua Zhao, the director of the JTL Urban Mobility Lab; discuss findings from their recent article in the Journal of Urban Technology about the impacts of different degrees of locational privacy protection on the quality of ride-sharing, or “mobility-sharing,” services. Zhao is also director of the MIT Mobility Initiative, co-director of the MIT Energy Initiative’s (MITEI) Mobility Systems Center, and an associate professor of urban studies and planning. This research was supported by the Mobility Systems Center, one of MITEI’s Low-Carbon Energy Centers.
Q: What does your research tell us about the trade-offs in protecting a user’s locational privacy and the performance of ride-sharing applications?
A: By providing mobility-sharing applications with both spatial and temporal data on their activities, users could reveal personal habits, preferences, and behaviors. Masking location data in order to avoid the identification of users in case of data leakage, misusage, and/or security breaches increases user privacy. However, the loss of information can decrease data utility and lead to poorer quality of service, or lower efficiency, in a location-based system.
Our research focuses on mobility-sharing applications that hold promise for improving the efficiency of transportation and reducing vehicle miles traveled (VMT). In our study, we ask: How would location privacy-preserving techniques affect the performance of such applications, and more importantly, the aspects that most impact passengers, such as waiting time, VMT, and so on? The study compares different methods for masking data and different levels of location data anonymization, and provides useful insights into the trade-off between user privacy and the performance of mobility-sharing applications.
We specifically analyzed the case of carpooling between home and work, which is the largest contributor to traffic congestion and air pollution. The analyses allow a careful quantification of the effects of different privacy-preservation techniques on total saved mileage, showing that better savings can be obtained if users agree to trade convenience for privacy — more in terms of travel time than waiting time. For instance, by masking locations within a 200-meter radius, the total saved mileage decreases on average by 15 percent over the optimal solution with exact location information, while travel time for users increases by five minutes on average. Thus, by compromising on convenience, it is possible to preserve privacy while only minimally impacting total traveled mileage. This observation might be especially useful for city authorities and policy makers seeking a good compromise between their citizens’ individual right to privacy and the societal need to reduce VMT and energy consumption. For instance, introducing more flexibility in working hours could facilitate the above compromise in urban contexts.
Q: How does the cost of privacy affect a mobility-sharing system’s carbon footprint?
A: In our study, we compared the number of shared miles that would be obtained by optimally matching trips using exact location information with those obtained through increasingly anonymized data. We found that the higher the level of privacy that is granted to users, the fewer the shared miles: The percentage of shared miles decreases from 10 percent with minimal privacy preservation, up to 60 percent with the stricter privacy preservation policies. The values in between depend not only on the levels of location data anonymization considered, but also on the amount of discomfort we are giving to users (for example, longer riding and waiting times). In a nutshell, the cost of privacy in terms of increased carbon footprint might be very high, and it should be carefully balanced with city-level and societal-level sustainability targets.
Q: What next steps are you considering for your research, and how does your research support the decarbonization of the transportation sector?
A: Currently, users grant whole-data ownership and rights to these application companies, since otherwise they would not be able to use their services. If this scenario changes (for example, in response to new regulations), companies might start offering users benefits and rewards (for example, lower cost, higher priority, or higher score) to nudge them to fully or partially opt out from a “privacy option.” This would allow the system to fully access their location data or reduce the level of privacy users were initially granted. If the user could set a desired level of privacy or decide not to require any privacy at all, this would lead to different levels of data privacy within the same privacy-preserving system. Performing tests on the sensitivity of the system efficiency and quality of service with respect to the percentage of riders requesting privacy controls and the geographical distribution of those riders could be an interesting research direction to investigate.
Furthermore, the extent to which data privacy is perceived as a concern by shared mobility users is still largely unknown. Would users accept rewards and benefits from the companies to totally or partially relinquish their privacy rights?
Recently, another major factor potentially disrupting the shared mobility market has appeared and spread worldwide: the Covid-19 pandemic. How could this impact shared mobility? What if people keep social distancing in the long term and drastically change their mobility patterns? What if citizens worldwide adopt the view that owning a car and driving alone (or at most, with family members) is the safest way for their health to move within and among cities, to the detriment of shared mobility modes, such as carpooling, ride-hailing, ride-sharing, or car-sharing? Failing to anticipate and address these worst-case scenarios could lead to rising traffic and congestion, which in turn will harm the environment and public health. Our plan is to investigate to what extent people are willing to use smart mobility systems post-Covid-19, and to what extent health concerns and location data privacy could be an issue. More

Scientists have long sought to harness fusion as an inexhaustible and carbon-free energy source. Within the past few years, groundbreaking high-temperature superconductor technology (HTS) sparked a new vision for achieving practical fusion energy. This approach, known as the high-field pathway to fusion, aims to generate fusion in compact devices on a shorter timescale and lower cost than alternative approaches.
A key technical challenge to realizing this vision, though, has been getting HTS superconductors to work in an integrated way in the development of new, high-performance superconducting magnets, which will enable higher magnetic fields than previous generations of magnets, and are central to confining and controlling plasma reactions.
Now a team led by MIT’s Plasma Science and Fusion Center (PSFC) and MIT spinout company Commonwealth Fusion Systems (CFS), has developed and extensively tested an HTS cable technology that can be scaled and engineered into the high-performance magnets. The team’s research was published on Oct. 7 in Superconductor Science and Technology. Researchers included MIT assistant professor and principal investigator Zachary Hartwig; PSFC Deputy Head of Engineering Rui F. Vieira and other key PSFC technical and engineering staff; CFS Chief Science Officer Brandon Sorbom PhD ’17 and other CFS engineers; and scientists at CERN in Geneva, Switzerland, and at the Robinson Research Institute at Victoria University of Wellington, New Zealand. 
This development follows a recent boost to the high-field pathway, when 47 researchers from 12 institutions published seven papers in the Journal of Plasma Physics, showing that a high-field fusion device, called SPARC, built with such magnets would produce net energy — more energy than it consumes — something never previously demonstrated.
“The cable technology for SPARC is an important piece of the puzzle as we work to accelerate the timeline of achieving fusion energy,” says Hartwig, assistant professor of nuclear science and engineering, and leader of the research team at the PSFC. “If we’re successful in what we’re doing and in other technologies, fusion energy will start to make a difference in mitigating climate change — not in 100 years, but in 10 years.”
A super cable
The innovative technology described in the paper is a superconducting cable that conducts electricity with no resistance or heat generation and that will not degrade under extreme mechanical, electrical, and thermal conditions. Branded VIPER (an acronymic feat that stands for Vacuum Pressure Impregnated, Insulated, Partially transposed, Extruded, and Roll-formed), it consists of commercially produced thin steel tapes coated with HTS compound — yttrium-barium-copper-oxide — that are packaged into an assembly of copper and steel components to form the cable. Cryogenic coolant, such as supercritical helium, can flow easily through the cable to remove heat and keep the cable cold even under challenging conditions.
“One of our advances was figuring out a way to solder the HTS tape inside the cable, effectively making it a monolithic structure where everything is thermally connected,” says Sorbom. Yet VIPER can also be fashioned into twists and turns, using joints to create “almost any type of geometry,” he adds. This makes the cable an ideal building material for winding into coils capable of generating and containing magnetic fields of enormous strength, such as those required to make fusion devices substantially smaller than presently envisioned net-energy fusion devices.
Resilient and robust
“The key thing we can do with VIPER cable is make a magnetic field two to three times stronger at the size required than the present generation of superconducting magnet technology,” Hartwig says. The magnitude of the magnetic field in tokamaks plays a strong nonlinear role in determining plasma performance. For example, fusion power density scales as magnetic field to the fourth power: Doubling the field increases fusion power by 16 times or, conversely, the same fusion output power can be achieved in a device 16 times smaller by volume.
“In the development of high field magnets for fusion, HTS cables are an essential ingredient, and they’ve been missing,” says Soren Prestemon, director of the U.S. Magnet Development Program at the Lawrence Berkeley National Laboratory, who was not involved with this research. “VIPER is a breakthrough in the area of cable architecture — arguably the first candidate to be proven viable for fusion — and will enable the critical step forward to demonstration in a fusion reactor.” 
VIPER technology also presents a powerful approach to a particular problem in the superconducting magnet field, called a quench, “that has terrified engineers since they started building superconducting magnets,” says Hartwig. A quench is a drastic temperature increase that occurs when the cold cables can no longer conduct electrical current without any resistance. When quench occurs, instead of generating almost zero heat in the superconducting state, the electrical current generates substantial resistive heating in the cable.
“The rapid temperature rise can cause the magnet to potentially damage or destroy itself if the electrical current is not shut off,” says Hartwig.  “We want to avoid this situation or, if not, at least know about it as quickly and certainly as possible.”
The team incorporated two types of temperature-sensing fiber optic technology developed by collaborators at CERN and Robinson Research Institute. The fibers exhibited — for the first time on full-scale HTS cables and in representative conditions of high-magnetic field fusion magnets — sensitive and high-speed detection of temperature changes along the cable to monitor for the onset of quench.
Another key result was the successful incorporation of easily fabricated, low-electrical resistance, and mechanically robust joints between VIPER cables. Superconducting joints are often complex, challenging to make, and more likely to fail than others parts of a magnet; VIPER was designed to eliminate these issues. The VIPER joints have the additional advantage of being demountable, meaning they can be taken apart and reused with no impact on performance.
Prestemon notes that the cable’s innovative architecture directly impacts real-world challenges in operating fusion reactors of the future. “In an actual commercial fusion-energy-producing facility, intense heat and radiation deep inside the reactor will require routine component replacements,” he says. “Being able to take these joints apart and put them back together is a significant step towards making fusion a cost-effective proposition.”
The 12 VIPER cables that Hartwig’s team built, running between one and 12 meters in length, were evaluated with bending tests, thousands of sudden “on-off” mechanical cycles, multiple cryogenic thermal cycles, and dozens of quench-like events to simulate the kind of punishing conditions encountered in the magnets of a fusion device. The group successfully completed four multi-week test campaigns in four months at the SULTAN facility, a leading center for superconducting cable evaluation operated by Swiss Plasma Center, affiliated with Ecole Polytechnique Fédérale de Lausanne in Switzerland.
“This unprecedented rate of HTS cable testing at SULTAN shows the speed that technology can be advanced by an outstanding team with the mindset to go fast, the willingness to take risks, and the resources to execute,” says Hartwig. It is a sentiment that serves as the foundation of the SPARC project.
The SPARC team continues to improve VIPER cable and is moving on to the next project milestone in mid-2021: “We’ll be building a multi-ton model coil that will be similar to the size of a full-scale magnet for SPARC,” says Sorbom. These research activities will continue to advance the foundational magnet technologies for SPARC and enable the demonstration of net energy from fusion, a key achievement that signals fusion is a viable energy technology. “That will be a watershed moment for fusion energy,” says Hartwig.
Funding for this research was provided by CFS. More

When the pandemic drove MIT students from Cambridge, Massachusetts, in March, few suspected this disruption would prove beneficial. Yet for some undergraduate researchers working with the Department of Nuclear Science and Engineering (NSE), exile from campus spurred deeper exploration of known territory, and rewarding forays into less-familiar disciplines.
“I learned so much biology this summer,” says NSE major Natalie Montoya, whose senior thesis involves nuclear security and policy. When the pandemic scuttled her internship at the Lawrence Livermore National Laboratory, Montoya changed course, working instead with her NSE advisor R. Scott Kemp on projects aimed at improving Covid-19 diagnostics and testing.
Galvanized by these assignments, Montoya will split her remaining time at MIT between thesis research and Covid work: “Everyone wants things to get back to normal, and I think what I’m doing on Covid needs to happen right now.”
As a first-year student last year, Charlotte Wickert had seized an undergraduate research opportunity (UROP) aimed at improving simulations in nuclear reactors. When the pandemic arrived, her work with Benoit Forget’s Computational Reactor Physics Group, supervised by graduate student Amelia Trainer, only grew in scope.
“It was really, really cool when Amelia said, ‘This is your project,’” recalls Wickert. Her research focused on improving data used to model neutron collisions in reactors. “Not many people are looking at this area, and it was great to know there’s this little corner of nuclear physics where I did something that no one else had done before.”
A biology and chemistry major drawn to cancer biology and a medical career, Mriganka Mandal had been working on an immunotherapy study at the Whitehead institute for Biomedical Research when MIT shut down its labs. In search of an alternative UROP, Mandal recalled her positive experience in the spring with the remote version of 22.011 (Nuclear Engineering: Science, Systems and Society).
“Given how much I liked this class, I thought it would be great to develop practical experience in the nuclear field,” she says. Mandal’s queries landed her a project with NSE principal research scientist Charles W. Forsberg exploring a heat storage mechanism for use with renewable energy generation. “I didn’t have a background in thermodynamics beyond high school physics, but I found the work really appealing,” she says. “In quarantine it was difficult to remain motivated so I was very happy to engage and get stuff done as a remote researcher.”
During a Zoom-based NSE undergraduate research festival on Aug. 29, these students presented the results of their pandemic-bound summer work. In their “lightning” talks and subsequent interviews, they described the challenges and satisfactions of their endeavors. Professor Matteo Bucci, the NSE UROP coordinator, remarked that “the students’ research progress this past summer was impressive, and I am looking forward to what the fall and spring terms will bring, and to the next UROP research festival.”
Improving reactor simulations
In 6th grade, sophomore Charlotte Wickert decided on physics for her career after reading a novel about parallel universes. Then, as a high school junior dreaming of a fossil-free future, she realized that studying nuclear fission and fusion energy “could be a perfect way to combine all my interests.”
Soon after she arrived at MIT as an Air Force ROTC cadet, she signed up for a UROP in nuclear physics at an activities fair. Although she had not yet taken an NSE class, she thought research might be a perfect introduction to the field.
Wickert’s UROP, which began in her first year and expanded during summer 2020, focused on the behavior of thermal neutrons, subatomic particles crucial to the fission process in reactors.
“These slow-moving neutrons are more likely to cause fission, which is good, but we need to know where they’re going to avoid runaway reactions,” says Wickert. Her job involved gathering data and writing code characterizing the scattering of these neutrons as they interact with different materials in the reactor core. The data on slow-moving neutron scattering is out of date or incomplete, so the information Wickert incorporates in her coding may prove integral to new, detailed simulations undergirding the design and safe operation of nuclear systems.
“Sometimes it’s hard to remember that what I’m doing has physical significance, that it’s not just numbers on the screen,” she says. “But when I step back and think about the neutrons, I realize I’m changing interactions of particles, changing the physics of the situation.”
In the fall, from an Ann Arbor, Michigan, Airbnb rental shared with MIT classmates, Wickert plans to take her first (remote) NSE course, declare NSE as a second major with physics, and continue on this project “as a way of enriching sophomore year,” she says.
Tapping heat storage
It required some adjusting for Mriganka Mandal to take full advantage of her UROP analyzing large-scale systems for capturing heat that can be converted on demand to electricity. “Open-ended research was a first for me,” she says. “With lab and bench work, it’s very clear-cut: you’re looking for a specific protein, or how something interacts with a cell.” Nevertheless, says Mandal, she found herself intrigued.
“Energy storage is a critical problem as we try to move to a low-carbon economy; renewables can’t always handle peak electricity demand,” she says. Her particular research emphasis involved evaluating a heat storage system that uses crushed rock and molten nitrate salt in an insulated tank 1 kilometer long, 60 meters wide, and 20 meters tall — about two-thirds of the way from MIT to Harvard University.
“I was looking at the physical compatibility of different salts and rocks, and the density and heat capacity requirements,” she says. “For instance, there were problems when rocks contained iron, because salts acted as electrolytes, oxidizing the iron and making things physically unstable.” Mandal found the physics and chemistry quite fascinating: “I got to pull together my knowledge from different disciplines,” she says.
There were unanticipated payoffs such as online conferences with other researchers working on heat storage. “It was important to see people treat this problem as a pressing concern as we move away from fossil fuels,” she says.
After she returns to MIT from Charlottesville, Virginia, for fall semester, Mandal plans to extend her UROP, mathematically modeling her hypothetical heat storage system. At the same time, she will be taking more nuclear science classes to explore nuclear applications in medicine: “I’m very excited about the possibility of engineering nuclear therapies for disease therapeutics.”
From nuclear security to Covid
Natalie Montoya’s transition to remote student life meant placing her extracurricular career as a nationally ranked bench presser on hold, and figuring out a whole new path to graduating early (she’s a junior who is effectively a senior). So her shift during the summer from security studies to Covid-19 related research didn’t throw her too much. In fact, she found it refreshing to bring analytical and computational skills honed on nuclear security data to bear on a pressing public health problem.
Under the direction of Kemp, she developed a method for evaluating Covid-19 symptoms that could help with preliminary triaging where health-care systems are constrained. Her hometown of Rapid City, South Dakota, a stone’s throw from Mt. Rushmore, could benefit. “In a lot of places, testing is in short supply, and we wondered if we could create a self-check that would help people say right off the bat, Covid, or Not Covid,” she says.
Using Bayesian analysis on 14 symptoms found in Covid and more common illnesses like colds, Montoya found that “it’s not how many symptoms, but which ones” that point decisively toward this year’s coronavirus. Acute symptoms such as loss of taste and smell are exceedingly rare in most common infections and suggest Covid, but runny noses and sore muscles are poor indicators. She aims to host this simple program on an open website.
“I’m getting near wizard level in Excel and its weird functions, and I’ve learned how to hunt up data that doesn’t want to be found,” she says. “And I can even explain the difference between incidence and prevalence,” she says. Communicating research clearly counts, whatever the research field. 
Montoya is already putting her new-found skills to use as she gears up for the next phase of her Covid-19 research this fall. In addition to creating a wider-ranging symptom assessment tool, she is working on analyzing the effectiveness of a promising new rapid Covid-19 test. “Tests in most of the country take a week, which means the possibility of people with no symptoms superspreading the virus,” she says. “We need to get the pandemic curve down faster, and with this research, I see a chance to make a real difference — even if I haven’t gone through medical school.” More

While ride-sharing services like Grab, Uber, and Gojek have become a pervasive part of life, many countries in the Asia Pacific region are still unconvinced when it comes to micro-mobilities such as bike and scooter sharing. While the convenience offered by these is great, especially in this Covid-19 era when people may remain wary of crowding in buses and metro trains, there is a need for in-depth knowledge of these new transportation options to help guide policy and regulation.
A group of scientists in the Senseable City Lab at MIT and the Future Urban Mobility (FM) Interdisciplinary Research Group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, set out to better understand the phenomenon and inform policy-making through a comparative analysis of bike-sharing and scooter-sharing activities in Singapore.
The researchers shared their findings in a paper titled “Understanding spatio-temporal heterogeneity of bike-sharing and scooter-sharing mobility” published in the journal Computers, Environment and Urban Systems. The study is based on real usage records containing location and time of departures and arrivals in two distinct areas in Singapore.
“We constructed historical trajectories of the bike-sharing and scooter-sharing trips and compared usage patterns of the two systems at the Marina Bay area and the NUS campus,” says Rui Zhu, a postdoc at SMART FM. “Our results showed increased sharing frequency and decreased fleet size for scooter-sharing, suggesting that it performs better than bike-sharing.”
More specifically, the sharing frequency was increased from less than one time per day for bike-sharing to more than three times per day for scooter-sharing, but the researchers believe that can be improved even further to create a more profitable service.
The study also found that shared scooters in Marina Bay were frequently left away from their designated parking spaces or charging stations, indicating costly and labor-intensive maintenance since employees need to collect and transport scooters between stations continuously. However, the statistics also showed that over 28 percent and 26 percent of trips departed from and arrived at non-stations respectively, suggesting that users actually utilized most of the inappropriately returned scooters.
In addition, the study revealed quantitative changes in trips over time, distances, and duration, and the influence of weather on the demand of micro-mobilities.
“In Singapore and a few other cities, dockless bike-sharing systems rose and fell in just one year, followed by an explosion of docking scooter-sharing systems. But we didn’t have the necessary insights for appropriate business and policy decisions,” Zhu explains. “Our study goes deeper into the problems and possibilities of micro-mobility sharing and suggests how these services can be improved.”
To facilitate a sustainable scooter-sharing service, the researchers suggest optimizing the fleet size of stations and their locations, regulating returning behaviors more strictly, enabling scooters to have autonomous repositioning functionality, and increasing the useful battery life of scooters.
To increase battery life, they suggest installing a photovoltaic module on scooters for solar charging during trips and parking time or equipping conventional dock-based stations with grid charging or solar charging platforms, allowing for an environmentally friendly solution that will be able to reduce carbon footprints.
While the business model and user behavior greatly impact the success of mobility-sharing services, government policy also plays a significant role. Supportive policies or regulations on controlling fleet sizes and limiting usage to discrete areas are huge drivers for the sustainable development of the new transportation modes. With this study, SMART’s researchers hope to fill existing gaps in knowledge about micro-mobility sharing to help inform policy decisions.
SMART was established by MIT in partnership with the National Research Foundation of Singapore (NRF) in 2007. SMART is the first entity in the Campus for Research Excellence and Technological Enterprise (CREATE) developed by NRF. SMART serves as an intellectual and innovation hub for research interactions between MIT and Singapore, performing cutting-edge research in areas of interest to both. SMART currently comprises an Innovation Center and six Interdisciplinary Research Groups: Future Urban Mobility, Antimicrobial Resistance, BioSystems and Micromechanics, Critical Analytics for Manufacturing Personalized-Medicine, Disruptive and Sustainable Technologies for Agricultural Precision, and Low Energy Electronic Systems.
The Future Urban Mobility group harnesses new technological and institutional innovations to create the next generation of urban mobility systems to increase accessibility, equity, safety, and environmental performance for the citizens and businesses of Singapore and other metropolitan areas, worldwide.
SMART research is supported by the NRF and situated in CREATE. More

Stepping up its ongoing efforts to inform and empower the public on the issue of climate change, MIT today announced a dramatic overhaul of the MIT Climate Portal, climate.mit.edu, which provides timely, science-based information about the causes and consequences of climate change — and what can be done to address it.
“From vast wildfires to an unusually active hurricane season, we are already getting a glimpse of what our climate-changed future looks like,” says Maria T. Zuber, MIT’s vice president for research. “With this website, we aim to communicate in rigorous but accessible ways what the science tells us: Yes, human-caused climate change is an urgent, serious problem; and yes, we can do something about it. Addressing climate change is an institutional priority, and this kind of public engagement is one way we hope to accelerate solutions.”
Survey research shows that increasing numbers of people, both in the United States and around the world, are concerned about climate change. But in the U.S., research also shows that members of the public rarely hear about or discuss the issue. Researchers at the Yale Program on Climate Change Communication and the George Mason University Center for Climate Change Communication have suggested that there might exist a climate change “spiral of silence,” in which “even people who care about the issue shy away from discussing it because they so infrequently hear other people talking about it.”
MIT’s efforts at public engagement on climate change are intended to help break this “spiral” — encouraging people to discuss climate change while also providing them with resources to discuss it in a way informed by the latest science and research. These engagement efforts are part of a commitment the Institute made in its 2015 Plan for Action on Climate Change “to offer the public a trusted source of climate change information, to engage leaders and citizens in the effort for solutions, and to use MIT’s expertise in online education to dramatically expand our reach.”
“We often talk about reaching people whom we call the ‘climate curious’ –— people who want to learn more about what climate change means for them and their communities and, of course, what they can do about it,” says John Fernández, the director of the MIT Environmental Solutions Initiative and a professor in the Department of Architecture. “Our goal is for this website to become a dependable resource for people across the U.S. and all over the world, so that they can have effective conversations about the urgency of the climate problem and our ability, even now, to reduce the grave risks it presents.”
Managed by the MIT Environmental Solutions Initiative, the MIT Climate Portal features a range of content, including a comprehensive climate change primer and climate-related news from all corners of the Institute. New features launched today include brief “explainers,” written by faculty and scientists at MIT, that provide high-level overviews of important topics like wildfires, carbon pricing, renewable energy, and ocean acidification. Also new to the website is an “Ask MIT Climate” feature, where members of the public can get answers to their own questions about climate change. (If you have a question about climate change that you would like the MIT Climate Portal to answer, email climate@mit.edu.)
The site also offers a clearinghouse of everything climate-related happening at MIT, from events to course offerings, to keep interested students, alumni, parents, faculty, and staff members up to date. Just as importantly, it creates a digital meeting place for members of the MIT community to share their latest work on climate change. Faculty, students, and staff across the Institute for years have made significant contributions to improving public understanding of and engagement with climate change, with tools like the climate simulators created by the MIT Sloan Sustainability Initiative; the Climate CoLab platform; and a number of public events, contests, and educational materials. The site will make these resources accessible in one place.
In addition to the MIT Climate Portal, MIT had previously launched two other digital resources for the public: an online, Webby Award-winning interactive primer on climate change, and a podcast series, TILclimate (short for “Today I Learned: Climate”). Both of these resources are accessible through the portal.
By enlisting MIT students in editorial aspects of the new website, the project is also proving to be a valuable hands-on educational tool. For example, for the “Ask MIT Climate” feature, students take questions about climate change submitted by users and then, under the guidance of MIT faculty members, research the answers and write responses.
“We see this as a powerful learning opportunity, a way for MIT students to strengthen their content knowledge about climate change, energy, and sustainability, but also to improve their ability to effectively communicate complex science and engineering topics to diverse audiences, a critical skill that will serve them well after they leave MIT,” says Fernández.
The new website is not static: New content will be developed and added over time, and all departments, labs, and centers at MIT that work on climate change are invited to contribute to it. Members of the MIT community who want to learn more about getting involved, or who have ideas for subjects to cover, are encouraged to contact the Climate Portal team. More

Two and a half years ago, MIT entered into a research agreement with startup company Commonwealth Fusion Systems to develop a next-generation fusion research experiment, called SPARC, as a precursor to a practical, emissions-free power plant.
Now, after many months of intensive research and engineering work, the researchers charged with defining and refining the physics behind the ambitious tokamak design have published a series of papers summarizing the progress they have made and outlining the key research questions SPARC will enable.
Overall, says Martin Greenwald, deputy director of MIT’s Plasma Science and Fusion Center and one of the project’s lead scientists, the work is progressing smoothly and on track. This series of papers provides a high level of confidence in the plasma physics and the performance predictions for SPARC, he says. No unexpected impediments or surprises have shown up, and the remaining challenges appear to be manageable. This sets a solid basis for the device’s operation once constructed, according to Greenwald.
Greenwald wrote the introduction for a set of seven research papers authored by 47 researchers from 12 institutions and published today in a special issue of the Journal of Plasma Physics. Together, the papers outline the theoretical and empirical physics basis for the new fusion system, which the consortium expects to start building next year.
SPARC is planned to be the first experimental device ever to achieve a “burning plasma” — that is, a self-sustaining fusion reaction in which different isotopes of the element hydrogen fuse together to form helium, without the need for any further input of energy. Studying the behavior of this burning plasma — something never before seen on Earth in a controlled fashion — is seen as crucial information for developing the next step, a working prototype of a practical, power-generating power plant.
Such fusion power plants might significantly reduce greenhouse gas emissions from the power-generation sector, one of the major sources of these emissions globally. The MIT and CFS project is one of the largest privately funded research and development projects ever undertaken in the fusion field.
“The MIT group is pursuing a very compelling approach to fusion energy.” says Chris Hegna, a professor of engineering physics at the University of Wisconsin at Madison, who was not connected to this work. “They realized the emergence of high-temperature superconducting technology enables a high magnetic field approach to producing net energy gain from a magnetic confinement system. This work is a potential game-changer for the international fusion program​.”
The SPARC design, though about the twice the size as MIT’s now-retired Alcator C-Mod experiment and similar to several other research fusion machines currently in operation, would be far more powerful, achieving fusion performance comparable to that expected in the much larger ITER tokamak being built in France by an international consortium. The high power in a small size is made possible by advances in superconducting magnets that allow for a much stronger magnetic field to confine the hot plasma.
The SPARC project was launched in early 2018, and work on its first stage, the development of the superconducting magnets that would allow smaller fusion systems to be built, has been proceeding apace. The new set of papers represents the first time that the underlying physics basis for the SPARC machine has been outlined in detail in peer-reviewed publications. The seven papers explore the specific areas of the physics that had to be further refined, and that still require ongoing research to pin down the final elements of the machine design and the operating procedures and tests that will be involved as work progresses toward the power plant.
The papers also describe the use of calculations and simulation tools for the design of SPARC, which have been tested against many experiments around the world. The authors used cutting-edge simulations, run on powerful supercomputers, that have been developed to aid the design of ITER. The large multi-institutional team of researchers represented in the new set of papers aimed to bring the best consensus tools to the SPARC machine design to increase confidence it will achieve its mission.
The analysis done so far shows that the planned fusion energy output of the SPARC tokamak should be able to meet the design specifications with a comfortable margin to spare. It is designed to achieve a Q factor — a key parameter denoting the efficiency of a fusion plasma — of at least 2, essentially meaning that twice as much fusion energy is produced as the amount of energy pumped in to generate the reaction. That would be the first time a fusion plasma of any kind has produced more energy than it consumed.
The calculations at this point show that SPARC could actually achieve a Q ratio of 10 or more, according to the new papers. While Greenwald cautions that the team wants to be careful not to overpromise, and much work remains, the results so far indicate that the project will at least achieve its goals, and specifically will meet its key objective of producing a burning plasma, wherein the self-heating dominates the energy balance.
Limitations imposed by the Covid-19 pandemic slowed progress a bit, but not much, he says, and the researchers are back in the labs under new operating guidelines.
Overall, “we’re still aiming for a start of construction in roughly June of ’21,” Greenwald says. “The physics effort is well-integrated with the engineering design. What we’re trying to do is put the project on the firmest possible physics basis, so that we’re confident about how it’s going to perform, and then to provide guidance and answer questions for the engineering design as it proceeds.”
Many of the fine details are still being worked out on the machine design, covering the best ways of getting energy and fuel into the device, getting the power out, dealing with any sudden thermal or power transients, and how and where to measure key parameters in order to monitor the machine’s operation.
So far, there have been only minor changes to the overall design. The diameter of the tokamak has been increased by about 12 percent, but little else has changed, Greenwald says. “There’s always the question of a little more of this, a little less of that, and there’s lots of things that weigh into that, engineering issues, mechanical stresses, thermal stresses, and there’s also the physics — how do you affect the performance of the machine?”
The publication of this special issue of the journal, he says, “represents a summary, a snapshot of the physics basis as it stands today.” Though members of the team have discussed many aspects of it at physics meetings, “this is our first opportunity to tell our story, get it reviewed, get the stamp of approval, and put it out into the community.”
Greenwald says there is still much to be learned about the physics of burning plasmas, and once this machine is up and running, key information can be gained that will help pave the way to commercial, power-producing fusion devices, whose fuel — the hydrogen isotopes deuterium and tritium — can be made available in virtually limitless supplies.
The details of the burning plasma “are really novel and important,” he says. “The big mountain we have to get over is to understand this self-heated state of a plasma.”
“The analysis presented in these papers will provide the world-wide fusion community with an opportunity to better understand the physics basis of the SPARC device and gauge for itself the remaining challenges that need to be resolved,” says George Tynan, professor of mechanical and aerospace engineering at the University of California at San Diego, who was not connected to this work. “Their publication marks an important milestone on the road to the study of burning plasmas and the first demonstration of net energy production from controlled fusion, and I applaud the authors for putting this work out for all to see.”​
Overall, Greenwald says, the work that has gone into the analysis presented in this package of papers “helps to validate our confidence that we will achieve the mission. We haven’t run into anything where we say, ‘oh, this is predicting that we won’t get to where we want.” In short, he says, “one of the conclusions is that things are still looking on-track. We believe it’s going to work.” More