MIT News: Civil & Environmental Engineering

July 17, 2018

  • In 2016, MIT announced that it would neutralize 17 percent of its carbon emissions through a unique collaboration with Boston Medical Center and Post Office Square Redevelopment Corporation: The three entitites formed an alliance to buy solar power, demonstrating a partnership model for climate-change mitigation and the advancement of large scale solar development.

    Boston Mayor Martin Walsh recently announced that his city will undertake a similar but much larger effort to purchase solar energy in conjunction with cities across the U.S., including Chicago, Houston, Los Angeles, Orlando, and Portland, Oregon. At the time of this announcement, Walsh called upon more cities to join in this collective renewable energy initiative. In describing the agreement, Boston officials said the effort is modeled on MIT’s 2016 effort.

    Julie Newman, the Institute’s director of sustainability, spoke with MIT News about the power of MIT’s pioneering model for purchasing solar energy.

    Q: Can you describe MIT’s alliance with Boston Medical Center and Post Office Square Redevelopment Corporation to purchase solar energy?

    A: Climate partnerships are not new to cities like Boston and Cambridge, where urban stakeholders work together to try to advance solutions for climate mitigation and resiliency. In Boston, MIT participates on the city’s Green Ribbon Commission, which is co-chaired by Mayor Walsh and includes leaders from Boston’s business, institutional, and civic sectors. In MIT’s host city of Cambridge, the Institute works collaboratively with the municipality on a range of initiatives related to solar energy, resiliency planning, building energy use, and other efforts focused on climate change.

    In October 2016 MIT, Boston Medical Center, and Post Office Square Redevelopment Corporation formed an alliance to buy electricity from a large new solar power installation. The goal was to add carbon-free energy to the grid and, equally important, we wanted to demonstrate a partnership model for other organizations.

    Our power purchase agreement, or PPA, enabled the construction of Summit Farms, a 650-acre, 60-megawatt solar farm in North Carolina. The facility is now operational and is one of the largest renewable-energy projects ever built in the U.S. through an alliance like this.

    MIT committed to buying 73 percent of the power generated by Summit Farms’ 255,000 solar panels, with BMC purchasing 26 percent and POS purchasing the remainder. At the time, MIT’s purchase of 44 megawatts — equivalent to 40 percent of the Institute’s 2016 electricity use — was among the largest publicly announced purchases of solar energy by any American college or university.

    Summit Farms would not have been built without the commitments from MIT and its partners. The emissions-free power it generates every year represents an annual abatement of carbon dioxide emissions equivalent to removing more than 25,000 cars from the road.

    A unique provision in the agreement between MIT and Summit Farms will provide MIT researchers with access to a wealth of data on performance parameters at the North Carolina site. This research capability amplifies the project’s impact and contributes to making the MIT campus a true living laboratory for advances in technology, policy, and business models.

    Q: What exactly has the City of Boston announced that it plans to do, and how is this modeled on MIT’s solar-power collaboration?

    A: MIT, our collaborators, the city of Boston, and the numerous other cities joining Mayor Walsh all share an interest in reducing carbon emissions at the global scale. We want solutions that will transform the energy market, create clean-energy jobs, and sustain healthy, thriving communities. In collaboration, we can have a greater impact than we could if we tried to mitigate emissions on an institute-by-institute or city-by-city basis. By combining our purchasing power, we can escalate the demand for renewable energy more rapidly, triggering new development and installation of renewables through the energy sector in the U.S. 

    Our project used a convening force, the group A Better City, to invite disparate entities to combine efforts to increase demand for renewable energy. Similarly, Mayor Walsh has called upon leading members of the Climate Mayors Network, representing over 400 cities and 70 million people, to combine their collective purchasing and bargaining power to reduce energy costs and spark the creation of large-scale renewable energy projects across the country. This invitation has launched a coast-to-coast effort to increase the demand for renewable energy across the eight regional grids.

    Q: Has the Institute fielded expressions of interest from other entities interested in trying this model? Is there evidence that it will spread further?

    A: We are excited about this solution, and we’ve shared this model of solar-collaboration with peers across the country. We’ve hosted webinars, meetings, and presentations, and received immediate and passionate interest from statewide systems, large corporations, and multiuniversity partnerships that have since pursued collective renewable energy projects. We can now point to a dozen or more projects that have been inspired by this model and  are pursuing renewable energy aggregation.

    It is important to note that the success of an external collaboration is only as strong as our internal collaboration. The development of the MIT power purchase agreement relied on expertise from more than eight academic and administrative departments, including researchers from related fields, engineers in our utilities area, and staff with expertise in purchasing, finance, and legal areas. We are on the verge of tapping back into these partnerships as we look ahead to determine what is next.

    We now have real-time data on energy, emissions avoidance, and financial performance and can evaluate the real world impacts of our project. These findings will influence our thinking going forward. We are considering such questions as how can MIT continue to amplify our efforts? How can we shape our energy impact in the world, and what is the best way to pursue our interest in collectively transforming the energy market? We are continuously broadening our clean energy knowledge base, from multidimensional carbon-accounting frameworks to the exploration of new technologies. Along the way, we have learned that the location of a new wind or solar project matters significantly to its carbon dioxide reduction impact. (The project has a greater benefit if it’s located in a dirtier power grid.) This will inform our work as we actively pursue new partnerships for future scenarios.

July 16, 2018

  • The U.S. Defense Advanced Research Projects Agency (DARPA) has honored Connor Coley, who is currently pursuing his graduate degree in chemical engineering, as one of 50 DARPA Risers for 2018.

    The award states that DARPA Risers are considered by the agency to be “up-and-coming standouts in their fields, capable of discovering and leveraging innovative opportunities for technological surprise — the heart of DARPA’s national security mission.”

    Currently a member of the Klavs Jensen and William Green research groups, Coley is focused on improving automation and computer assistance in synthesis planning and reaction optimization with medicinal chemistry applications. He is more broadly interested in the design and construction of automated microfluidic platforms for analytics (e.g. kinetic or process understanding) and on-demand synthesis.

    The goal of many synthetic efforts, particularly in early stage drug discovery, is to produce a target small molecule of interest. At MIT, Coley’s early graduate research focused on streamlining organic synthesis from an experimental perspective: screening and optimizing chemical reactions in a microfluidic platform using as little material as possible.

    But even with an automated platform to do just that, researchers need to know exactly what reaction to run. They must first figure out the best synthetic route to make the target compound and then turn to the chemical literature to define a suitable parameter space to operate within. As part of the DARPA Make-It program, Coley and his colleagues started working toward a much more ambitious goal. Instead of automating only the execution of reactions, could a researcher automate the entire workflow of route identification, process development, and experimental execution?

    Coley's recent research has focused on various aspects of computer-aided synthesis planning to help make a fully autonomous synthetic chemistry platform, leveraging techniques in machine learning to meaningfully generalize historical reaction data. This includes questions of how best to propose novel retrosynthetic pathways and validate those suggestions in silico before carrying them out in the laboratory. The overall goal of his work is to develop models and computational approaches that — in combination with more traditional automation techniques — will improve the efficiency of small molecule discovery.

    “It's been a privilege to participate in the Make-It program and I am grateful for being named a DARPA Riser,” Coley says. “I'm excited to take part in the D60 anniversary event and talk about my ideas for how this work can be extended to more broadly transform the process of molecular discovery.”

    Coley received his BS in chemical engineering from Caltech in 2014 and is a recipient of MIT’s Robert T. Haslam Presidential Graduate Fellowship.

    Coley will participate in D60, DARPA’s 60th Anniversary Symposium, Sept. 5-7 at Gaylord National Harbor. D60 will provide attendees the opportunity to engage with up-and-coming innovators, including some of today’s most creative and accomplished scientists and technologists. DARPA works to inspire attendees to explore future technologies, their potential application to tomorrow’s technical and societal challenges, and the dilemmas those applications may engender. D60 participants will have the opportunity to be a part of the new relationships, partnerships, and communities of interest that this event aims to foster, and advance dialogue on the pursuit of science in the national interest.

  • Kristala Jones Prather will be the first person to tell you the difference between science and engineering. She’ll also be the first to tell you how important both are to the research process.

    “Science is about discovery, and engineering is about application,” Prather says. “The beauty of being a scientist and doing discovery work is the freedom and creativity. For engineers, it’s all about how these discoveries can be applied and solve problems in the real world.”

    She would know: Over the course of her career, she’s been both. While working in bioprocess research and development at Merck, Prather delved into the engineering side of biology and chemistry. “My decision to work in industry before pursuing an academic career was very intentional,” she says. “I wanted to get a sense of what to think about when bringing products to market. How is new technology adopted? Can you improve upon existing processes?”

    Prather’s early years in industry shaped her knowledge of the process pipeline she is currently seeking to streamline through scientific inquiry. As the Arthur D. Little Professor of Chemical Engineering at MIT, she conducts research that ties together the fields of energy, biology, and chemistry. While biology and energy are most often connected in discussions of biofuels, Prather’s research focuses on a different kind of energy advancement: more energy-efficient processes for the manufacture of biochemicals.

    “I tell my students, look at the carpet in this room,” Prather says. “The probability is high that 50 percent or more of the materials in that carpet were produced using oil. So how do we decrease that number?” Prather’s lab works on engineering bacteria to produce biochemicals, thus replacing the fossil-fuel based processes currently responsible for making so many of the world’s materials.

    Such research requires expertise in chemical engineering, biological engineering, and genetics. Using genetic engineering, Prather and her team can manipulate the genes of microbes to control the kind and quantity of products they produce. These products could be anything from insulin or human growth hormone to the synthetic materials whose production would otherwise have required the use of oil or other fossil-based products.

    “The goal in exploring bio-based methods for creating these chemicals is to design a less energy-intensive process that is still cost-competitive,” she says. “We want to use less energy to get to the same molecules.”

    Yet for all the engineering knowledge that Prather gained while she was working in industry, something major was missing.

    “When I looked at the part of my job I liked best, it had to do with mentoring young scientists,” she says. “Training and teaching them how to be independent researchers in their fields was the most important and enjoyable part of the job to me.” This realization spurred Prather to make the switch back to academia that she had always been planning. “In industry, you eventually move away from mentoring younger researchers as you move up in the ranks,” she says. “In academia, mentoring is the kernel at the center that always stays the same.”

    With her current classes, Prather has ample opportunity to mentor the next generation of MIT scientists and engineers. She teaches 10.10 (Introduction to Chemical Engineering) to first-year and sophomore undergraduates, as well as 10.542 (Biochemical Engineering) for graduate students and upper-level undergrads. Opportunities to reach students present themselves outside of the classroom as well. In fall 2017, Prather was invited by MIT President L. Rafael Reif to be part of a small group of professors addressing incoming first-years at a welcome assembly their first week on campus.

    The advice she gave to students then is a message she believes all MIT students need to hear.

    “You need to embrace failure,” she says. “Recognize that not everything you attempt is going to work out.”

    But there’s an important corollary to this advice. “Students, especially at MIT, should also remember: You belong here,” she says. “It doesn’t matter how many AP classes you come in with or anything like that. And there are a lot of people here to help you get through.”

    When asked what the most challenging part of being a professor is, Prather says: “Just how much stuff there is to do. Not the volume, but the diversity — that mix of administrative and academic work.” Still, the most rewarding part of the job is easy to pinpoint. “The students,” she says. “The day a student in my lab defends their thesis is the happiest and saddest day of my life. Happiest because I’m so proud of what they’ve done. But saddest because the time has come for them to leave.”

    Prather and her colleague Angela Belcher, the James Mason Crafts Professor of Biological Engineering and Materials Science at MIT, are advancing the future of energy bioscience through their work as co-directors of MITEI’s Low-Carbon Energy Center for Energy Bioscience Research. The goal of the center, Prather says, is to “use the toolbox of biology to engineer solutions to clean energy challenges.”

    Prather and Belcher are bringing together a host of biological and chemical engineers from across the Institute to perform research in a wide range of areas. Prather’s own work using genetics to engineer biochemicals is complemented by myriad other projects her colleagues have in the works. Research topics range from biochemical remediation, or the use of bacteria to clean up oil spills; to biological generation of liquid fuels from natural gas; to engineering a virus capable of improving solar cell efficiency.

    “We’re really trying to pull together the collective talents of researchers at MIT who are using biology to solve a range of problems,” she says. The results could have positive impacts on critical fields including renewable energy, clean fuel sources, infrastructure, storage, and chemical processing and production.

    This article appears in the Spring 2018 issue of Energy Futures, the magazine of the MIT Energy Initiative.

  • There may be more than a quadrillion tons of diamond hidden in the Earth’s interior, according to a new study from MIT and other universities. But the new results are unlikely to set off a diamond rush. The scientists estimate the precious minerals are buried more than 100 miles below the surface, far deeper than any drilling expedition has ever reached.

    The ultradeep cache may be scattered within cratonic roots — the oldest and most immovable sections of rock that lie beneath the center of most continental tectonic plates. Shaped like inverted mountains, cratons can stretch as deep as 200 miles through the Earth’s crust and into its mantle; geologists refer to their deepest sections as “roots.”

    In the new study, scientists estimate that cratonic roots may contain 1 to 2 percent diamond. Considering the total volume of cratonic roots in the Earth, the team figures that about a quadrillion (1016) tons of diamond are scattered within these ancient rocks, 90 to 150 miles below the surface.   

    “This shows that diamond is not perhaps this exotic mineral, but on the [geological] scale of things, it’s relatively common,” says Ulrich Faul, a research scientist in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “We can’t get at them, but still, there is much more diamond there than we have ever thought before.”

    Faul’s co-authors include scientists from the University of California at Santa Barbara, the Institut de Physique du Globe de Paris, the University of California at Berkeley, Ecole Polytechnique, the Carnegie Institution of Washington, Harvard University, the University of Science and Technology of China, the University of Bayreuth, the University of Melbourne, and University College London.

    A sound glitch

    Faul and his colleagues came to their conclusion after puzzling over an anomaly in seismic data. For the past few decades, agencies such as the United States Geological Survey have kept global records of seismic activity — essentially, sound waves traveling through the Earth that are triggered by earthquakes, tsunamis, explosions, and other ground-shaking sources. Seismic receivers around the world pick up sound waves from such sources, at various speeds and intensities, which seismologists can use to determine where, for example, an earthquake originated.

    Scientists can also use this seismic data to construct an image of what the Earth’s interior might look like. Sound waves move at various speeds through the Earth, depending on the temperature, density, and composition of the rocks through which they travel. Scientists have used this relationship between seismic velocity and rock composition to estimate the types of rocks that make up the Earth’s crust and parts of the upper mantle, also known as the lithosphere.

    However, in using seismic data to map the Earth’s interior, scientists have been unable to explain a curious anomaly: Sound waves tend to speed up significantly when passing through the roots of ancient cratons. Cratons are known to be colder and less dense than the surrounding mantle, which would in turn yield slightly faster sound waves, but not quite as fast as what has been measured.   

    “The velocities that are measured are faster than what we think we can reproduce with reasonable assumptions about what is there,” Faul says. “Then we have to say, ‘There is a problem.’ That’s how this project started.”

    Diamonds in the deep

    The team aimed to identify the composition of cratonic roots that might explain the spikes in seismic speeds. To do this, seismologists on the team first used seismic data from the USGS and other sources to generate a three-dimensional model of the velocities of seismic waves traveling through the Earth’s major cratons.

    Next, Faul and others, who in the past have measured sound speeds through many different types of minerals in the laboratory, used this knowledge to assemble virtual rocks, made from various combinations of minerals. Then the team calculated how fast sound waves would travel through each virtual rock, and found only one type of rock that produced the same velocities as what the seismologists measured: one that contains 1 to 2 percent diamond, in addition to peridotite (the predominant rock type of the Earth’s upper mantle) and minor amounts of eclogite (representing subducted oceanic crust). This scenario represents at least 1,000 times more diamond than people had previously expected.

    “Diamond in many ways is special,” Faul says. “One of its special properties is, the sound velocity in diamond is more than twice as fast as in the dominant mineral in upper mantle rocks, olivine.”

    The researchers found that a rock composition of 1 to 2 percent diamond would be just enough to produce the higher sound velocities that the seismologists measured. This small fraction of diamond would also not change the overall density of a craton, which is naturally less dense than the surrounding mantle.

    “They are like pieces of wood, floating on water,” Faul says. “Cratons are a tiny bit less dense than their surroundings, so they don’t get subducted back into the Earth but stay floating on the surface. This is how they preserve the oldest rocks. So we found that you just need 1 to 2 percent diamond for cratons to be stable and not sink.”

    In a way, Faul says cratonic roots made partly of diamond makes sense. Diamonds are forged in the high-pressure, high-temperature environment of the deep Earth and only make it close to the surface through volcanic eruptions that occur every few tens of millions of years. These eruptions carve out geologic “pipes” made of a type of rock called kimberlite (named after the town of Kimberley, South Africa, where the first diamonds in this type of rock were found). Diamond, along with magma from deep in the Earth, can spew out through kimberlite pipes, onto the surface of the Earth.

    For the most part, kimberlite pipes have been found at the edges of cratonic roots, such as in certain parts of Canada, Siberia, Australia, and South Africa. It would make sense, then, that cratonic roots should contain some diamond in their makeup.  

    “It’s circumstantial evidence, but we’ve pieced it all together,” Faul says. “We went through all the different possibilities, from every angle, and this is the only one that’s left as a reasonable explanation.”

    This research was supported, in part, by the National Science Foundation. 

  • In an advance that could lead to new treatments for a variety of diseases, MIT researchers have devised a new way to deliver messenger RNA (mRNA) into cells.

    Messenger RNA, a large nucleic acid that encodes genetic information, can direct cells to produce specific proteins. Unlike DNA, mRNA is not permanently inserted into a cell’s genome, so it could be used to produce a therapeutic protein that is only needed temporarily. It can also be used to produce gene-editing proteins that alter a cell’s genome and then disappear, minimizing the risk of off-target effects.

    Because mRNA molecules are so large, researchers have had difficulty designing ways to efficiently get them inside cells. It has also been a challenge to deliver mRNA to specific organs in the body. The new MIT approach, which involves packaging mRNA into polymers called amino-polyesters, addresses both of those obstacles.

    “We are excited by the potential of these formulations to deliver mRNA in a safe and effective manner,” says Daniel Anderson, an associate professor in MIT’s Department of Chemical Engineering and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science (IMES).

    Anderson is the senior author of the paper, which appears in the journal Advanced Materials. The paper’s lead authors are MIT postdoc Piotr Kowalski and former visiting graduate student Umberto Capasso Palmiero of Politecnico di Milano. Other authors are research associate Yuxuan Huang, postdoc Arnab Rudra, and David H. Koch Institute Professor Robert Langer.

    Polymer control

    Cells use mRNA to carry protein-building instructions from DNA to ribosomes, where proteins are assembled. By delivering synthetic mRNA to cells, researchers hope to be able to stimulate cells to produce proteins that could be used to treat disease. Scientists have developed some effective methods for delivering smaller RNA molecules, and a number of these materials have shown potential in clinical trials.

    The MIT team decided to package mRNA into new polymers called amino-polyesters. These polymers are biodegradable, and unlike many other delivery polymers, they do not have a strong positive charge, which may make them less likely to damage cells.

    To create the polymers, the researchers used an approach that allows them to control the properties of the polymer, such as its molecular weight. This means that the quality of the polymers produced will be the similar in each batch, which is important for clinical transition and often not the case with other polymer synthesis methods.

    “Being able to control the molecular weight and the properties of your material helps to be able to reproducibly make nanoparticles with similar qualities, and to produce carriers starting from building blocks that are biocompatible could reduce their toxicity,” Capasso Palmiero says.

    “It makes clinical translation much harder if you don’t have control over the reproducibility of the delivery system and the released degradation products, which is a challenge for polymer-based nucleic acid delivery,” Kowalski says.

    For this study, the researchers created a diverse library of polymers that varied in the composition of amino-alcohol core and the lactone monomers. The researchers also varied the length of polymer chains and the presence of carbon atom side chains in the lactone subunits.

    After creating about three dozen different polymers, the researchers combined them with lipids, which help stabilize the particles, and encapsulated mRNA within the nanoparticles.

    In tests in mice, the researchers identified several particles that could effectively deliver mRNA to cells and induce the cells to synthesize the protein encoded by the mRNA. To their surprise, they also found that several of the nanoparticles appeared to preferentially accumulate in certain organs, including the liver, lungs, heart, and spleen. This kind of selectivity may allow researchers to deliver specific therapies to certain locations in the body.

    “It is challenging to achieve tissue-specific mRNA delivery,” says Yizhou Dong, an associate professor of pharmaceutics and pharmaceutical chemistry at Ohio State University, who was not involved in the research. “The findings in this report are very exciting and provide new insights on chemical features of polymers and their interactions with different tissues in vivo. These novel polymeric nanomaterials will facilitate systemic delivery of mRNA for therapeutic applications.”

    Targeting disease

    The researchers did not investigate what makes different nanoparticles go to different organs, but they hope to further study that question. Particles that specifically target different organs could be very useful for treating lung diseases such as pulmonary hypertension, or for delivering vaccines to immune cells in the spleen, Kowalski says. Another possible application is using the particles to deliver mRNA encoding the proteins required for the genome-editing technique known as CRISPR-Cas9, which can make permanent additions or deletions to a cell’s genome.

    Anderson’s lab is now working in collaboration with researchers at the Polytechnic University of Milan on the next generation of these polymers in hopes of improving the efficiency of RNA delivery and enhancing the particles’ ability to target specific organs.

    “There is definitely a potential to increase the efficacy of these materials by further modifications, and also there is potential to hopefully find particles with different organ-specificity by extending the library,” Kowalski says.

    The research was funded by the U.S. Defense Advanced Research Projects Agency and the Progetto Roberto Rocca.