MIT News - Materials science - Materials Science and Engineering - DMSE MIT News is dedicated to communicating to the media and the public the news and achievements of the students, faculty, staff and the greater MIT community. en Mon, 09 Mar 2020 00:00:00 -0400 2020 MacVicar Faculty Fellows named Anikeeva, Fuller, Tisdale, and White receive MIT&#039;s highest honor in undergraduate teaching. Mon, 09 Mar 2020 00:00:00 -0400 Alison Trachy | Registrar’s Office <p><em>This article has been updated to reflect the cancellation of the 2020 MacVicar Day symposium.</em></p> <p>The Office of the Vice Chancellor and the Registrar’s Office have announced this year’s Margaret MacVicar Faculty Fellows: materials science and engineering Professor Polina Anikeeva, literature Professor Mary Fuller, chemical engineering Professor William Tisdale, and electrical engineering and computer science Professor Jacob White.</p> <p>Role models both in and out of the classroom, the new fellows have tirelessly sought to improve themselves, their students, and the Institute writ large. They have reimagined curricula, crossed disciplines, and pushed the boundaries of what education can be. They join a matchless academy of scholars committed to exceptional instruction and innovation.</p> <p>For nearly three decades, the <a href="">MacVicar Faculty Fellows Program</a> has been recognizing exemplary undergraduate teaching and advising around the Institute. The program was&nbsp;named after Margaret MacVicar, the first dean for undergraduate education and founder of the Undergraduate Research Opportunities Program (UROP). Nominations are made by departments and include letters of support from colleagues, students, and alumni. Fellows are appointed to 10-year terms in which they receive $10,000 per year of discretionary funds.</p> <p>This year’s MacVicar Day symposium — which had been scheduled for this Friday, March 13 — has been canceled after <a href="" target="_self">new MIT policies on events</a> were set in response to the 2019 novel coronavirus.</p> <p><strong>Polina Anikeeva</strong></p> <p>“I’m speechless,” Polina Anikeeva, associate professor of materials science and engineering and brain and cognitive sciences, says of becoming a MacVicar Fellow. “In my opinion, this is the greatest honor one could have at MIT.”</p> <p>Anikeeva received her PhD from MIT in 2009 and became a professor in the Department of Materials Science and Engineering two years later. She attended St. Petersburg State Polytechnic University for her undergraduate education. Through her research — which combines materials science, electronics, and neurobiology — she works to better understand and treat brain disorders.</p> <p>Anikeeva’s colleague Christopher Schuh says, “Her ability and willingness to work with students however and whenever they need help, her engaging classroom persona, and her creative solutions to real-time challenges all culminate in one of MIT’s most talented and beloved undergraduate professors.”</p> <p>As an instructor, advisor, and <a href="">marathon runner</a>, Anikeeva has learned the importance of finding balance. Her colleague Lionel Kimerling reflects on this delicate equilibrium: “As a teacher, Professor Anikeeva is among the elite who instruct, inspire, and nurture at the same time. It is a difficult task to demand rigor with a gentle mentoring hand.”</p> <p>Students call her classes “incredibly hard” but fun and exciting at the same time. She is “the consummate scientist, splitting her time evenly between honing her craft, sharing knowledge with students and colleagues, and mentoring aspiring researchers,” wrote one.</p> <p>Her passion for her work and her devotion to her students are evident in the nomination letters. One student recounted their first conversation: “We spoke for 15 minutes, and after talking to her about her research and materials science, I had never been so viscerally excited about anything.” This same student described the guidance and support Anikeeva provided her throughout her time at MIT. After working with Anikeeva to apply what she learned in the classroom to a real-world problem, this student recalled, “I honestly felt like an engineer and a scientist for the first time ever. I have never felt so fulfilled and capable. And I realize that’s what I want for the rest of my life — to feel the highs and lows of discovery.”</p> <p>Anikeeva champions her students in faculty and committee meetings as well. She is a “reliable advocate for student issues,” says Caroline Ross, associate department head and professor in DMSE. “Professor Anikeeva is always engaged with students, committed to student well-being, and passionate about education.”</p> <p>“Undergraduate teaching has always been a crucial part of my MIT career and life,” Anikeeva reflects. “I derive my enthusiasm and energy from the incredibly talented MIT students — every year they surprise me with their ability to rise to ever-expanding intellectual challenges. Watching them grow as scientists, engineers, and — most importantly — people is like nothing else.”</p> <p><strong>Mary Fuller</strong></p> <p>Experimentation is synonymous with education at MIT and it is a crucial part of literature Professor Mary Fuller’s classes. As her colleague Arthur Bahr notes, “Mary’s habit of starting with a discrete practical challenge can yield insights into much broader questions.”</p> <p>Fuller attended Dartmouth College as an undergraduate, then received both her MA and PhD in English and American literature from The Johns Hopkins University. She began teaching at MIT in 1989. From 2013 to 2019, Fuller was head of the Literature Section. Her successor in the role, Shankar Raman, says that her nominators “found [themselves] repeatedly surprised by the different ways Mary has pushed the limits of her teaching here, going beyond her own comfort zones to experiment with new texts and techniques.”</p> <p>“Probably the most significant thing I’ve learned in 30 years of teaching here is how to ask more and better questions,” says Fuller. As part of a series of discussions on ethics and computing, she has explored the possibilities of <a href="">artificial intelligence</a> from a literary perspective. She is also developing a tool for the edX platform called PoetryViz, which would allow MIT students and students around the world to practice close reading through poetry annotation in an entirely new way.</p> <p>“We all innovate in our teaching. Every year. But, some of us innovate more than others,” Krishna Rajagopal, dean for digital learning, observes. “In addition to being an outstanding innovator, Mary is one of those colleagues who weaves the fabric of undergraduate education across the Institute.”</p> <p>Lessons learned in Fuller’s class also underline the importance of a well-rounded education. As one alumna reflected, “Mary’s teaching carried a compassion and ethic which enabled non-humanities students to appreciate literature as a diverse, valuable, and rewarding resource for personal and social reflection.”</p> <p>Professor Fuller, another student remarked, has created “an environment where learning is not merely the digestion of rote knowledge, but instead the broad-based exploration of ideas and the works connected to them.”</p> <p>“Her imagination is capacious, her knowledge is deep, and students trust her — so that they follow her eagerly into new and exploratory territory,” says Professor of Literature Stephen Tapscott.</p> <p>Fuller praises her students’ willingness to take that journey with her, saying, “None of my classes are required, and none are technical, so I feel that students have already shown a kind of intellectual generosity by putting themselves in the room to do the work.”</p> <p>For students, the hard work is worth it. Mary Fuller, one nominator declared, is exactly “the type of deeply impactful professor that I attended MIT hoping to learn from.”</p> <p><strong>William Tisdale</strong></p> <p>William Tisdale is the ARCO Career Development Professor of chemical engineering and, according to his colleagues, a “true star” in the department.</p> <p>A member of the faculty since 2012, he received his undergraduate degree from the University of Delaware and his PhD from the University of Minnesota. After a year as a postdoc at MIT, Tisdale became an assistant professor. His <a href="">research interests</a> include nanotechnology and energy transport.</p> <p>Tisdale’s colleague Kristala Prather calls him a “curriculum fixer.” During an internal review of Course 10 subjects, the department discovered that 10.213 (Chemical and Biological Engineering) was the least popular subject in the major and needed to be revised. After carefully evaluating the coursework, and despite having never taught 10.213 himself, Tisdale envisioned a novel way of teaching it. With his suggestions, the class went from being “despised” to loved, with subject evaluations improving by 70 percent from one spring to the next. “I knew Will could make a difference, but I had no idea he could make that big of a difference in just one year,” remarks Prather. One student nominator even went so far as to call 10.213, as taught by Tisdale, “one of my best experiences at MIT.”</p> <p>Always patient, kind, and adaptable, Tisdale’s willingness to tackle difficult problems is reflected in his teaching. “While the class would occasionally start to mutiny when faced with a particularly confusing section, Prof. Tisdale would take our groans on with excitement,” wrote one student. “His attitude made us feel like we could all get through the class together.” Regardless of how they performed on a test, wrote another, Tisdale “clearly sent the message that we all always have so much more to learn, but that first and foremost he respected you as a person.”</p> <p>“I don’t think I could teach the way I teach at many other universities,” Tisdale says. “MIT students show up on the first day of class with an innate desire to understand the world around them; all I have to do is pull back the curtain!”</p> <p>“Professor Tisdale remains the best teacher, mentor, and role model that I have encountered,” one student remarked. “He has truly changed the course of my life.”</p> <p>“I am extremely thankful to be at a university that values undergraduate education so highly,” Tisdale says. “Those of us who devote ourselves to undergraduate teaching and mentoring do so out of a strong sense of responsibility to the students as well as a genuine love of learning. There are few things more validating than being rewarded for doing something that already brings you joy.”</p> <p><strong>Jacob White</strong></p> <p>Jacob White is the Cecil H. Green Professor of Electrical Engineering and Computer Science (EECS) and chair of the Committee on Curricula. After completing his undergraduate degree at MIT, he received a master’s degree and doctorate from the University of California at Berkeley. He has been a member of the Course 6 faculty since 1987.</p> <p>Colleagues and students alike observed White’s dedication not just to teaching, but to improving teaching throughout the Institute. As Luca Daniel and Asu Ozdaglar of the EECS department noted in their nomination letter, “Jacob completely understands that the most efficient way to make his passion and ideas for undergraduate education have a real lasting impact is to ‘teach it to the teachers!’”</p> <p>One student wrote that White “has spent significant time and effort educating the lab assistants” of 6.302 (Feedback System Design). As one of these teaching assistants confirmed, White’s “enthusiastic spirit” inspired them to spend hours discussing how to best teach the subject. “Many people might think this is not how they want to spend their Thursday nights,” the student wrote. “I can speak for myself and the other TAs when I say that it was an incredibly fun and educational experience.”</p> <p>His work to improve instruction has even expanded to other departments. A colleague describes White’s efforts to revamp 8.02 (Physics II) as “Herculean.” Working with a group of students and postdocs to develop experiments for this subject, “he seemed to be everywhere at once … while simultaneously teaching his own class.” Iterations took place over a year and a half, after which White trained the subject’s TAs as well. Hundreds of students are benefitting from these improved experiments.</p> <p>White is, according to Daniel and Ozdaglar, “a colleague who sincerely, genuinely, and enormously cares about our undergraduate students and their education, not just in our EECS department, but also in our entire MIT home.”</p> <p>When he’s not fine-tuning pedagogy or conducting teacher training, he is personally supporting his students. A visiting student described White’s attention: “He would regularly meet with us in groups of two to make sure we were learning. In a class of about 80 students in a huge lecture hall, it really felt like he cared for each of us.”</p> <p>And his zeal has rubbed off: “He made me feel like being excited about the material was the most important thing,” one student wrote.</p> <p>The significance of such a spark is not lost on White. "As an MIT freshman in the late 1970s, I joined an undergraduate research program being pioneered by Professor Margaret MacVicar," he says. "It was Professor MacVicar and UROP that put me on the academic's path of looking for interesting problems with instructive solutions. It is a path I have walked for decades, with extraordinary colleagues and incredible students. So, being selected as a MacVicar Fellow? No honor could mean more to me."</p> The 2020 MacVicar Faculty Fellows are: (clockwise from top left) Polina Anikeeva, Jacob White, William Tisdale, and Mary Fuller.Photos (clockwise from top left): Lillie Paquette, Sampson Wilcox, Webb Chappell, Jon SachsOffice of the Vice Chancellor, MacVicar fellows, Undergraduate Research Opportunities Program (UROP), Materials Science and Engineering, Literature, EdX, Electrical engineering and computer science (EECS), School of Engineering, School of Humanities Arts and Social Sciences, Faculty, Awards, honors and fellowships, Education, teaching, academics, Mentoring, Undergraduate, Chemical engineering School of Engineering fourth quarter 2019 awards Faculty members recognized for excellence via a diverse array of honors, grants, and prizes over the last quarter. Fri, 06 Mar 2020 13:30:01 -0500 School of Engineering <p>Members of the MIT engineering faculty receive many awards in recognition of their scholarship, service, and overall excellence. Every quarter, the School of Engineering publicly recognizes their achievements by highlighting the honors, prizes, and medals won by faculty working in our academic departments, labs, and centers.</p> <p>Hal Abelson, of the Department of Electrical Engineering and Computer Science,&nbsp;received an <a href="">honorary doctorate in education from the Education University of Hong Kong</a>&nbsp;on Nov. 22, 2019.</p> <p>Jesús del Alamo, of the Department of Electrical Engineering and Computer Science, <a href="">won the University Researcher Award</a> from the Semiconductor Industry Association and the Semiconductor Research Corporation on Nov. 7, 2019.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>Mohammad Alizadeh, of the Department of Electrical Engineering and Computer Science,&nbsp;won the&nbsp;<a href="">2019 VMware Systems Research Award</a>&nbsp;on Dec. 18, 2019.</p> <p>Hari Balakrishnan, of the Department of Electrical Engineering and Computer Science,&nbsp;was named a&nbsp;<a href="">2020 fellow of the Institute of Electrical and Electronics Engineers</a> (IEEE)&nbsp;on Dec. 3, 2019.</p> <p>Irmgard Bischofberger, of the Department of Mechanical Engineering, won the&nbsp;<a href="">2019 APS/DFD Milton van Dyke Award</a>&nbsp;on Dec. 4, 2019.</p> <p>Adam Chlipala, of the Department of Electrical Engineering and Computer Science,&nbsp;was named a distinguished member of the Association for Computing Machinery on Dec. 20, 2019.</p> <p>William Freeman, of the Department of Electrical Engineering and Computer Science, <a href="">won the Distinguished Researcher Award</a> from the IEEE Computer Society's Technical Committee on Pattern Analysis and Machine Intelligence on Oct. 30, 2019.</p> <p>Shafi Goldwasser, of the Department of Electrical Engineering and Computer Science,&nbsp;received an <a href="">honorary doctorate of science from Oxford University</a> on June 26, 2019, and she received an <a href="">honorary doctorate in mathematics from the University of Waterloo</a>&nbsp;on June 13, 2019.</p> <p>Wesley L. Harris, of the Department of Aeronautics and Astronautics, was named a&nbsp;<a href="">2019 AAAS Fellow</a>&nbsp;on Nov. 26, 2019.</p> <p>Jonathan How, of the Department of Aeronautics and Astronautics, won the&nbsp;<a href="">2020 AIAA Intelligent Systems Award</a>&nbsp;on Dec. 5, 2019.</p> <p>Roger Kamm, of the Department of Mechanical Engineering,&nbsp;won the&nbsp;<a href="">Shu Chien Achievement Award</a>&nbsp;on Jan. 2.</p> <p>David Karger, of the Department of Electrical Engineering and Computer Science, was <a href="">inducted into the American Academy of Arts and Sciences</a>&nbsp;on Nov. 12, 2019.</p> <p>Heather Lechtman, of the Department of Materials Science and Engineering, <a href="">won the Pomerance Award for Scientific Contributions to Archaeology</a>&nbsp;on Jan. 4.</p> <p>Charles Leiserson, of the Department of Electrical Engineering and Computer Science, <a href="">won the Test of Time Award for 1999</a> from IEEE Symposium on the Foundations of Computer Science on Nov. 9, 2019.</p> <p>Nancy Leveson, of the Department of Aeronautics and Astronautics, won the&nbsp;<a href="">2020 IEEE Medal for Environmental and Safety Technologies</a> on Dec. 18, 2019.</p> <p>Barbara Liskov, Institute Professor Emerita of the Department of Electrical Engineering and Computer Science, received an <a href="">honorary doctorate in mathematics from the University of Waterloo</a>&nbsp;on June 13, 2019.</p> <p>Leonid Mirny, of the Institute for Medical Engineering and Science,&nbsp;was selected for the&nbsp;<a href="">Chaires Blaise Pascal 2019</a>&nbsp;on Oct. 30, 2019.</p> <p>Dava Newman, of the Department of Aeronautics and Astronautics, was <a href="">elected to the Aerospace Corporation’s Board of Trustees</a>&nbsp;on Dec. 23, 2019.</p> <p>Wim van Rees, of the Department of Mechanical Engineering,&nbsp;won the&nbsp;<a href="">2019 APS/DFD Milton van Dyke Award</a>&nbsp;on Dec. 4, 2019.</p> <p>Ellen Roche, of the Department of Mechanical Engineering,&nbsp;was named <a href="">associate scientific advisor of <em>Science Translational Medicine</em></a>&nbsp;on Jan. 17.</p> <p>Kripa Varanasi, of the Department of Mechanical Engineering, won the&nbsp;<a href="">2019 APS/DFD Milton van Dyke Award</a>&nbsp;on Dec. 4, 2019.</p> <p>Alan Willsky (post-tenure), of the Department of Electrical Engineering and Computer Science,&nbsp;won the&nbsp;<a href="">IEEE Jack S. Kilby Signal Processing Medal</a>&nbsp;on May 17, 2019.</p> <p>Maria Yang, Sang-Gook Kim, and Caitlin Mueller, of the Department of Mechanical Engineering, won the&nbsp;<a href="">National Science Foundation LEAP HI Award</a>&nbsp;on Dec. 4, 2019.</p> <p>Xuanhe Zhao, of the Department of Mechanical Engineering,&nbsp;won the&nbsp;<a href="">Thomas J.R. Hughes Young Investigator Award</a>&nbsp;on Jan. 2.</p> Members of the MIT engineering faculty receive many awards in recognition of their scholarship, service, and overall excellence.Photo: Lillie Paquette/School of EngineeringSchool of Engineering, Mechanical engineering, Awards, honors and fellowships, Faculty, Electrical Engineering & Computer Science (eecs), DMSE, Aeronautical and astronautical engineering Novel method for easier scaling of quantum devices System “recruits” defects that usually cause disruptions, using them to instead carry out quantum operations. Thu, 05 Mar 2020 23:59:59 -0500 Rob Matheson | MIT News Office <p>In an advance that may help researchers scale up quantum devices, an MIT team has developed a method to “recruit” neighboring quantum bits made of nanoscale defects in diamond, so that instead of causing disruptions they help carry out quantum operations.</p> <p>Quantum devices perform operations using quantum bits, called “qubits,” that can represent the two states corresponding to classic binary bits — a 0 or 1 — or a “quantum superposition” of both states simultaneously. The unique superposition state can enable quantum computers to solve problems that are practically impossible for classical computers, potentially spurring breakthroughs in biosensing, neuroimaging, machine learning, and other applications.</p> <p>One promising qubit candidate is a defect in diamond, called a nitrogen-vacancy (NV) center, which holds electrons that can be manipulated by light and microwaves. In response, the defect emits photons that can carry quantum information. Because of their solid-state environments, however, NV centers are always surrounded by many other unknown defects with different spin properties, called “spin defects.” When the measurable NV-center qubit interacts with those spin defects, the qubit loses its coherent quantum state — “decoheres”—&nbsp;and operations fall apart. Traditional solutions try to identify these disrupting defects to protect the qubit from them.</p> <p>In a paper published Feb. 25 in <em>Physical Letters Review</em>, the researchers describe a method that uses an NV center to probe its environment and uncover the existence of several nearby spin defects. Then, the researchers can pinpoint the defects’ locations and control them to achieve a coherent quantum state — essentially leveraging them as additional qubits.</p> <p>In experiments, the team generated and detected quantum coherence among three electronic spins — scaling up the size of the quantum system from a single qubit (the NV center) to three qubits (adding two nearby spin defects). The findings demonstrate a step forward in scaling up quantum devices using NV centers, the researchers say. &nbsp;</p> <p>“You always have unknown spin defects in the environment that interact with an NV center. We say, ‘Let’s not ignore these spin defects, which [if left alone] could cause faster decoherence. Let’s learn about them, characterize their spins, learn to control them, and ‘recruit’ them to be part of the quantum system,’” says the lead co-author Won Kyu Calvin Sun, a graduate student in the Department of Nuclear Science and Engineering and a member of the Quantum Engineering group. “Then, instead of using a single NV center [or just] one qubit, we can then use two, three, or four qubits.”</p> <p>Joining Sun on the paper are lead author Alexandre Cooper ’16 of Caltech; Jean-Christophe Jaskula, a research scientist in the MIT Research Laboratory of Electronics (RLE) and member of the Quantum Engineering group at MIT; and Paola Cappellaro, a professor in the Department of Nuclear Science and Engineering, a member of RLE, and head of the Quantum Engineering group at MIT.</p> <p><strong>Characterizing defects</strong></p> <p>NV centers occur where carbon atoms in two adjacent places in a diamond’s lattice structure are missing — one atom is replaced by a nitrogen atom, and the other space is an empty “vacancy.” The NV center essentially functions as an atom, with a nucleus and surrounding electrons that are extremely sensitive to tiny variations in surrounding electrical, magnetic, and optical fields. Sweeping microwaves across the center, for instance, makes it change, and thus control, the spin states of the nucleus and electrons.</p> <p>Spins are measured using a type of magnetic resonance spectroscopy. This method plots the frequencies of electron and nucleus spins in megahertz as a “resonance spectrum” that can dip and spike, like a heart monitor. Spins of an NV center under certain conditions are well-known. But the surrounding spin defects are unknown and difficult to characterize.</p> <p>In their work, the researchers identified, located, and controlled two electron-nuclear spin defects near an NV center. They first sent microwave pulses at specific frequencies to control the NV center. Simultaneously, they pulse another microwave that probes the surrounding environment for other spins. They then observed the resonance spectrum of the spin defects interacting with the NV center.</p> <p>The spectrum dipped in several spots when the probing pulse interacted with nearby electron-nuclear spins, indicating their presence. The researchers then swept a magnetic field across the area at different orientations. For each orientation, the defect would “spin” at different energies, causing different dips in the spectrum. Basically, this allowed them to measure each defect’s spin in relation to each magnetic orientation. They then plugged the energy measurements into a model equation with unknown parameters. This equation is used to describe the quantum interactions of an electron-nuclear spin defect under a magnetic field. Then, they could solve the equation to successfully characterize each defect.</p> <p><strong>Locating and controlling</strong></p> <p>After characterizing the defects, the next step was to characterize the interaction between the defects and the NV, which would simultaneously pinpoint their locations. To do so, they again swept the magnetic field at different orientations, but this time looked for changes in energies describing the interactions between the two defects and the NV center. The stronger the interaction, the closer they were to one another. They then used those interaction strengths to determine where the defects were located, in relation to the NV center and to each other. That generated a good map of the locations of all three defects in the diamond.</p> <p>Characterizing the defects and their interaction with the NV center allow for full control, which involves a few more steps to demonstrate. First, they pump the NV center and surrounding environment with a sequence of pulses of green light and microwaves that help put the three qubits in a well-known quantum state. Then, they use another sequence of pulses that ideally entangles the three qubits briefly, and then disentangles them, which enables them to detect the three-spin coherence of the qubits.</p> <p>The researchers verified the three-spin coherence by measuring a major spike in the resonance spectrum. The measurement of the spike recorded was essentially the sum of the frequencies of the three qubits. If the three qubits for instance had little or no entanglement, there would have been four separate spikes of smaller height.</p> <p>“We come into a black box [environment with each NV center]. But when we probe the NV environment, we start seeing dips and wonder which types of spins give us those dips. Once we [figure out] the spin of the unknown defects, and their interactions with the NV center, we can start controlling their coherence,” Sun says. “Then, we have full universal control of our quantum system.”</p> <p>Next, the researchers hope to better understand other environmental noise surrounding qubits. That will help them develop more robust error-correcting codes for quantum circuits. Furthermore, because on average the process of NV center creation in diamond creates numerous other spin defects, the researchers say they could potentially scale up the system to control even more qubits. “It gets more complex with scale. But if we can start finding NV centers with more resonance spikes, you can imagine starting to control larger and larger quantum systems,” Sun says.</p> An MIT team found a way to “recruit” normally disruptive quantum bits (qubits) in diamond to, instead, help carry out quantum operations. This approach could be used to help scale up quantum computing systems. Image: Christine Daniloff, MITResearch, Computer science and technology, Quantum computing, Nuclear science and engineering, Nanoscience and nanotechnology, Sensors, Research Laboratory of Electronics, Materials Science and Engineering, Physics, School of Engineering QS World University Rankings rates MIT No. 1 in 12 subjects for 2020 Institute ranks second in five subject areas. Tue, 03 Mar 2020 19:01:01 -0500 MIT News Office <p>MIT has been honored with 12 No. 1 subject rankings in the QS World University Rankings for 2020.</p> <p>The Institute received a No. 1 ranking in the following QS subject areas: Architecture/Built Environment; Chemistry; Computer Science and Information Systems; Chemical Engineering; Civil and Structural Engineering; Electrical and Electronic Engineering; Mechanical, Aeronautical and Manufacturing Engineering; Linguistics; Materials Science; Mathematics; Physics and Astronomy; and Statistics and Operational Research.</p> <p>MIT also placed second in five subject areas: Accounting and Finance; Biological Sciences; Earth and Marine Sciences; Economics and Econometrics; and Environmental Sciences.</p> <p>Quacquarelli Symonds Limited subject rankings, published annually, are designed to help prospective students find the leading schools in their field of interest. Rankings are based on research quality and accomplishments, academic reputation, and graduate employment.</p> <p>MIT has been ranked as the No. 1 university in the world by QS World University Rankings for eight straight years.</p> Afternoon light streams into MIT’s Lobby 7.Image: Jake BelcherRankings, Computer science and technology, Linguistics, Chemical engineering, Civil and environmental engineering, Mechanical engineering, Chemistry, Materials science, Mathematics, Physics, Economics, EAPS, Business and management, Accounting, Finance, DMSE, School of Engineering, School of Science, School of Architecture and Planning, Sloan School of Management, School of Humanities Arts and Social Sciences, Electrical Engineering & Computer Science (eecs), Architecture, Biology, Aeronautical and astronautical engineering Probing microscopic wiggles in squishy materials Technique could help improve design of soft materials to withstand jostling during transport or settling due to gravity. Tue, 03 Mar 2020 12:32:32 -0500 Jennifer Chu | MIT News Office <p>The term “colloidal gel” may not be a household name, but examples of these materials are everywhere in our daily lives, from toothpaste and shower gel to mayonnaise and yogurt. Colloidal gels are mixtures of particles suspended in fluid, and depending on how they are manipulated, these gels can flow like liquid or hold their shape like a solid.</p> <p>Now MIT researchers have peered into the microstructure of colloidal gels and identified a surprisingly rich variety of behaviors in these squishy, phase-defying materials.</p> <p>The team captured movies of colloidal gels as they formed, starting as individual particles in water and evolving into thick, uniform goo. The researchers zoomed in at various size scales to observe any activity in the morphing material, and discovered a range of scale-dependent behaviors.</p> <p>The researchers say their findings, reported on Feb. 27 in the journal <em>Physical Review Letters</em>, represent the first comprehensive study of the microstructure of colloidal gels. The work may help scientists tune the material properties of a variety of common products.</p> <p>One example that comes to mind, says study co-author Irmgard Bischofberger, is addressing the problem of the ever-present film of liquid on the surface of most yogurts. This liquid is either jostled out of the bulk of the yogurt during its transport, or it seeps out as a result of gravity, as the yogurt sits on a shelf over an extended period.</p> <p>“You want to have the yogurt withstand vibrations and gravity and avoid collapsing, but you don’t want to make your whole material stronger in a way that it won’t feel quite right when you eat it,” says Bischofberger, assistant professor of mechanical engineering at MIT. “Knowing all this information of how the material behaves across length scales allows you to find ways to tune a specific aspect of the material.”</p> <p>Bischofberger’s co-authors are MIT graduate student Jae Hyung Cho and Roberto Cerbino of the University of Milan.</p> <p><strong>A single shot</strong></p> <p>Scientists have typically explored the microstructure of colloidal gels using specialized laser setups to scatter light at multiple angles, to capture information about a material at different length scales. Bischofberger says that it would require many experimental runs to capture images of the same material at every resolution.</p> <p>The MIT team’s collaborator, Cerbino, had previously found that by using a simple optical microscope, with a resolution sharp enough to resolve everything from a material’s individual particles to its bulk properties, he could record movies of the material and then use a computer code to analyze the images at prescribed pixel lengths. For instance, the code could be set to analyze the motions within several pixels, or between hundreds of pixels, or across the entire image. In this way, Cerbino was able to capture the dynamics of a material across all length scales “in a single shot,” Bischofberger says.</p> <p>Cerbino previously demonstrated this technique, known as differential dynamic microscopy, or DDM, by imaging individual particles in a simple solution. For this new study, the team applied DDM to explore colloidal gels, a more complex class of materials.</p> <p>“These materials have fascinating properties,” Cho says. “To understand these properties, you need to understand the structures which span different length scales, from individual particle scales of tens of nanometers, to the structures they form, which span hundreds of microns across.”</p> <p><strong>Our bodies, our soft selves</strong></p> <p>Cho first designed a colloidal gel that the group could easily control and study. The material is a mixture of water and polystyrene particles, which Cho chose for their unique outer shell. Each particle is surrounded by a temperature-sensitive shell that, at low temperatures, resembles a spiky exterior that prevents a particle from getting too close to any neighboring particles. In warmer temperatures, the shell effectively shrinks, and the particle’s natural attractive force takes over, bringing it closer to other particles, which it can then attach to.</p> <p>The researchers mixed the particles at different concentrations with water and placed each sample on a thermoelectric plate, which they set under a conventional optical microscope. They took images of each sample as they turned up the plate’s temperature, and watched the samples evolve into a colloidal gel, turning from a milky liquid, to a thicker, yogurt-like consistency.</p> <p>Afterward, they used a computer code based on Fourier transform, a type of image processing technique that decomposes an image into various frequencies and spatial scales, to automatically extract motion data at different length scales, from individual particles to large, connected particle networks.</p> <p>“We use a single movie, composed of many images of a sample, and look at the sample through different windows,” Cho says.</p> <p>They found that, at the smallest scales, individual particles seemed to move around freely, wiggling and vibrating around each other. As the gel evolved, individual particles clumped together, forming larger strands or networks that moved together in more constrained fashion. At the end of the gel’s formation, multiple particle networks glommed onto each other across the material, forming a sort of stiff web that moved only slightly, as one homogenous structure.</p> <p><img alt="" src="/sites/" style="width: 400px; height: 400px;" /></p> <p><em><span style="font-size:10px;">As a colloidal gel transforms from a milky liquid to a thicker, yogurt-like consistency, its structure and motions also change, from individual, freely wiggling particles, to groups of particles that move together, and finally, to larger connected networks of particles that behave as one homogenous material.&nbsp;Courtesy of the researchers</span></em></p> <p>The structures they observed resembled a self-repeating fractal pattern, in which individual particles stuck to each other in ever larger networks and structures. Others have observed this fractal patterning in colloidal gels, over a certain range of length scales. This is the first time scientists have characterized the behavior of colloidal gels both inside and outside this fractal range, simultaneously, and observed different behaviors — in this case, degrees of motion — across different scales.</p> <p>“It’s this superposition of different modes of motion that gives colloidal gels these extremely rich properties,” Bischofberger says. “They can behave as both liquid and solid. All of that is a consequence of the fact that there is motion on so many different length scales, and that motion is different at different scales.”</p> <p>The researchers say their new method can be used to explore the microstructure of other soft materials such as biological tissues and cells.</p> <p>“Our bodies are soft materials like colloidal gels,” Cho notes. “If we use this technique to study biological systems, this could help in optimizing drug delivery, which involves transporting drugs through similar networks.”</p> <p>The team’s new technique, which is based on optical microscopes that are easily accessible in most laboratories, can be useful in not only characterizing, but also tuning the properties of soft materials.</p> <p>“If I want a strong material, do I have to play with what happens at the smallest scales or largest scale?” Bischofberger says. “For instance, if you want something with high strength but with a smooth texture what would I need to do to get such a system? Having all this microstructure information helps you know where to start with design.”</p> <p>This research was supported in part by the MIT Research Support Committee and Kwanjeong Educational Foundation.</p> Hand lotion, yogurt, and toothpaste are some examples of colloidal gels, which MIT researchers have now characterized in detail by studying movies of their microstructure.Materials Science and Engineering, Mechanical engineering, Research, School of Engineering Using light to put a twist on electrons Method with polarized light can create and measure nonsymmetrical states in a layered material. Wed, 26 Feb 2020 11:21:29 -0500 David Chandler | MIT News Office <p>Some molecules, including most of the ones in living organisms, have shapes that can exist in two different mirror-image versions. The right- and left-handed versions can sometimes have different properties, such that only one of them carries out the molecule’s functions. Now, a team of physicists has found that a similarly asymmetrical pattern can be induced and measured at will in certain exotic materials, using a special kind of light beam to stimulate the material.</p> <p>In this case, the phenomenon of “handedness,” known as chirality, occurs not in the structure of the molecules themselves, but in a kind of patterning in the density of electrons within the material. The researchers found that this asymmetric patterning can be induced by shining a circularly polarized mid-infrared light at an unusual material, a form of transition-metal dichalcogenide semimetal called TiSe<sub>2</sub>, or titanium diselenide.</p> <p>The new findings, which could open up new areas of research in the optical control of quantum materials, are described today in the journal <em>Nature</em> in a paper by MIT postdocs Suyang Xu and Qiong Ma, professors Nuh Gedik and Pablo Jarillo-Herrero, and 15 colleagues at MIT and other universities in the U.S., China, Taiwan, Japan, and Singapore.</p> <p>The team found that while titanium diselenide at room temperature has no chirality to it, as its temperature decreases it reaches a critical point where the balance of right-handed and left-handed electronic configurations gets thrown off and one type begins to dominate. They found that this effect could be controlled and enhanced by shining circularly polarized mid-infrared light at the material, and that the handedness of the light (whether the polarization rotates clockwise or counterclockwise) determines the chirality of the resulting patterning of electron distribution.</p> <p>“It’s an unconventional material, one that we don’t fully understand,” says Jarillo-Herrero. The material naturally structures itself into “loosely stacked two-dimensional layers on top of each other,” sort of like a sheaf of papers, he says.</p> <p>Within those layers, the distribution of electrons forms a “charge density wave function,” a set of ripple-like stripes of alternating regions where the electrons are more densely or less densely packed. These stripes can then form helical patterns, like the structure of a DNA molecule or a spiral staircase, which twist either to the right or to the left.</p> <p>Ordinarily, the material would contain equal amounts of the right- and left-handed versions of these charge density waves, and the effects of handedness would cancel out in most measurements. But under the influence of the polarized light, Ma says, “we found that we can make the material mostly prefer one of these chiralities. And then we can probe its chirality using another light beam.” It’s similar to the way a magnetic field can induce a magnetic orientation in a metal where ordinarily its molecules are randomly oriented and thus have no net magnetic effect.</p> <p>But inducing such an effect in the chirality with light within a solid material is something “nobody ever did before,” Gedik explains.&nbsp;</p> <p>After inducing the particular directionality using the circularly polarized light, “we can detect what kind of chirality there is in the material from the direction of the optically generated electric current,” Xu adds. Then, that direction can be switched to the other orientation if an oppositely polarized light source shines on the material.</p> <p>Gedik says that although some previous experiments had suggested that such chiral phases were possible in this material, “there were conflicting experiments,” so it had been unclear until now whether the effect was real. Though it’s too early in this work to predict what practical applications such a system might have, the ability to control electronic behavior of a material with just a light beam, he says, could have significant potential.</p> <p>While this study was carried out with one specific material, the researchers say the same principles may work with other materials as well. The material they used, titanium diselenide, is widely studied for potential uses in quantum devices, and further research on it may also offer insights into the behavior of superconducting materials.</p> <p>Gedik says that this way of inducing changes in the electronic state of the material is a new tool that could potentially be applied more broadly. “This interaction with light is a phenomenon which will be very useful in other materials as well, not just chiral material, but I suspect in affecting other kinds of orders as well,” he says.</p> <p>And, while chirality is well-known and widespread in biological molecules and in some magnetic phenomena, “this is the first time we’ve shown that this is happening in the electronic properties of a solid,” Jarillo-Herrero says.</p> <p>“The authors found two new things,” says Jasper van Wezel, a professor at the University of Amsterdam, who was not part of the research team. He said the new findings are “a new way of testing whether or not a material is chiral, and a way of enhancing the overall chirality in a big piece of material. Both breakthroughs are significant. The first as an addition to the experimental toolbox of materials scientists, the second as a way of engineering materials with desirable properties in terms of their interaction with light.”</p> <p>The research was supported by the U.S. Department of Energy, the Gordon and Betty Moore Foundation, and the National Science Foundation. The team included researchers at MIT, Carnegie Mellon University, Drexel University; National Sun Yat-Sen University, National Cheng Kung University, and Academia Sinica in Taiwan; Shenzen University in China, Northeastern University, the National University of Singapore, Cornell University, and the National Institute for Materials Science in Japan.</p> Beams of circularly polarized light (shown as blue spirals) can have two different mirror-image orientations, as shown here. When these beams strike a sheet of titanium diselenide (shown as a lattice of blue and silver balls), the electrons (aqua dots) in the material take on the handedness of the light's polarization.Image: Ella Maru StudioResearch, Physics, Materials Science and Engineering, School of Science, Department of Energy (DoE), National Science Foundation (NSF) Making a remarkable material even better Aerogels for solar devices and windows are more transparent than glass. Tue, 25 Feb 2020 13:10:01 -0500 Nancy W. Stauffer | MIT Energy Initiative <p>In recent decades, the search for high-performance thermal insulation for buildings has prompted manufacturers to turn to aerogels. Invented in the 1930s, these remarkable materials are translucent, ultraporous, lighter than a marshmallow, strong enough to support a brick, and an unparalleled barrier to heat flow, making them ideal for keeping heat inside on a cold winter day and outside when summer temperatures soar.</p> <p>Five years ago, researchers led by&nbsp;<a href="">Evelyn Wang</a>, a professor and head of the Department of Mechanical Engineering, and Gang Chen, the Carl Richard Soderberg Professor in Power Engineering, set out to add one more property to that list. They aimed to make a silica aerogel that was truly transparent.</p> <p>“We started out trying to realize an optically transparent, thermally insulating aerogel for solar thermal systems,” says Wang. Incorporated into a solar thermal collector, a slab of aerogel would allow sunshine to come in unimpeded but prevent heat from coming back out — a key problem in today’s systems. And if the transparent aerogel were sufficiently clear, it could be incorporated into windows, where it would act as a good heat barrier but still allow occupants to see out.</p> <p>When the researchers started their work, even the best aerogels weren’t up to those tasks. “People had known for decades that aerogels are a good thermal insulator, but they hadn’t been able to make them very optically transparent,” says Lin Zhao PhD ’19 of mechanical engineering. “So in our work, we’ve been trying to understand exactly why they’re not very transparent, and then how we can improve their transparency.”</p> <p><strong>Aerogels: opportunities and challenges</strong></p> <p>The remarkable properties of a silica aerogel are the result of its nanoscale structure. To visualize that structure, think of holding a pile of small, clear particles in your hand. Imagine that the particles touch one another and slightly stick together, leaving gaps between them that are filled with air. Similarly, in a silica aerogel, clear, loosely connected, nanoscale silica particles form a three-dimensional solid network within an overall structure that is mostly air. Because of all that air, a silica aerogel has an extremely low density — in fact, one of the lowest densities of any known bulk material — yet it’s solid and structurally strong, though brittle.</p> <p>If a silica aerogel is made of transparent particles and air, why isn’t it transparent? Because the light that enters doesn’t all pass straight through. It is diverted whenever it encounters an interface between a solid particle and the air surrounding it. Figure 1 in the slideshow above illustrates the process. When light enters the aerogel, some is absorbed inside it. Some — called direct transmittance — travels straight through. And some is redirected along the way by those interfaces. It can be scattered many times and in any direction, ultimately exiting the aerogel at an angle. If it exits from the surface through which it entered, it is called diffuse reflectance; if it exits from the other side, it is called diffuse transmittance.</p> <p>To make an aerogel for a solar thermal system, the researchers needed to maximize the total transmittance: the direct plus the diffuse components. And to make an aerogel for a window, they needed to maximize the total transmittance and simultaneously minimize the fraction of the total that is diffuse light. “Minimizing the diffuse light is critical because it’ll make the window look cloudy,” says Zhao. “Our eyes are very sensitive to any imperfection in a transparent material.”</p> <p><strong>Developing a model</strong></p> <p>The sizes of the nanoparticles and the pores between them have a direct impact on the fate of light passing through an aerogel. But figuring out that interaction by trial and error would require synthesizing and characterizing too many samples to be practical. “People haven’t been able to systematically understand the relationship between the structure and the performance,” says Zhao. “So we needed to develop a model that would connect the two.”</p> <p>To begin, Zhao turned to the radiative transport equation, which describes mathematically how the propagation of light (radiation) through a medium is affected by absorption and scattering. It is generally used for calculating the transfer of light through the atmospheres of Earth and other planets. As far as Wang knows, it has not been fully explored for the aerogel problem.</p> <p>Both scattering and absorption can reduce the amount of light transmitted through an aerogel, and light can be scattered multiple times. To account for those effects, the model decouples the two phenomena and quantifies them separately — and for each wavelength of light.</p> <p>Based on the sizes of the silica particles and the density of the sample (an indicator of total pore volume), the model calculates light intensity within an aerogel layer by determining its absorption and scattering behavior using predictions from electromagnetic theory. Using those results, it calculates how much of the incoming light passes directly through the sample and how much of it is scattered along the way and comes out diffuse.</p> <p>The next task was to validate the model by comparing its theoretical predictions with experimental results.</p> <p><strong>Synthesizing aerogels</strong></p> <p>Working in parallel, graduate student Elise Strobach of mechanical engineering had been learning how best to synthe­size aerogel samples — both to guide development of the model and ultimately to validate it. In the process, she produced new insights on how to synthesize an aerogel with a specific desired structure.</p> <p>Her procedure starts with a common form of silicon called silane, which chemically reacts with water to form an aerogel. During that reaction, tiny nucleation sites occur where particles begin to form. How fast they build up determines the end structure. To control the reaction, she adds a catalyst, ammonia. By carefully selecting the ammonia-to-silane ratio, she gets the silica particles to grow quickly at first and then abruptly stop growing when the precursor materials are gone — a means of producing particles that are small and uniform. She also adds a solvent, methanol, to dilute the mixture and control the density of the nucleation sites, thus the pores between the particles.</p> <p>The reaction between the silane and water forms a gel containing a solid nanostructure with interior pores filled with the solvent. To dry the wet gel, Strobach needs to get the solvent out of the pores and replace it with air — without crushing the delicate structure. She puts the aerogel into the pressure chamber of a critical point dryer and floods liquid CO<sub>2</sub>&nbsp;into the chamber. The liquid CO<sub>2</sub>&nbsp;flushes out the solvent and takes its place inside the pores. She then slowly raises the temperature and pressure inside the chamber until the liquid CO<sub>2</sub>&nbsp;transforms to its supercritical state, where the liquid and gas phases can no longer be differentiated. Slowly venting the chamber releases the CO<sub>2</sub>&nbsp;and leaves the aerogel behind, now filled with air. She then subjects the sample to 24 hours of annealing — a standard heat-treatment process — which slightly reduces scatter without sacrificing the strong thermal insulating behavior. Even with the 24 hours of annealing, her novel procedure shortens the required aerogel synthesis time from several weeks to less than four days.</p> <p><strong>Validating and using the model</strong></p> <p>To validate the model, Strobach fabricated samples with carefully controlled thicknesses, densities, and pore and particle sizes — as determined by small-angle X-ray scattering — and used a standard spectrophotometer to measure the total and diffuse transmittance.</p> <p>The data confirmed that, based on measured physical properties of an aerogel sample, the model could calculate total transmittance of light as well as a measure of clarity called haze, defined as the fraction of total transmittance that is made up of diffuse light.</p> <p>The exercise confirmed simplifying assumptions made by Zhao in developing the model. Also, it showed that the radiative properties are independent of sample geometry, so his model can simulate light transport in aerogels of any shape. And it can be applied not just to aerogels, but to any porous materials.</p> <p>Wang notes what she considers the most important insight from the modeling and experimental results: “Overall, we determined that the key to getting high transparency and minimal haze — without reducing thermal insulating capability — is to have particles and pores that are really small and uniform in size,” she says.</p> <p>One analysis demonstrates the change in behavior that can come with a small change in particle size. Many applications call for using a thicker piece of transparent aerogel to better block heat transfer. But increasing thickness may decrease transparency. With their samples, as long as particle size is small, increasing thickness to achieve greater thermal insulation will not significantly decrease total transmittance or increase haze.</p> <p><strong>Comparing aerogels from MIT and elsewhere</strong></p> <p>How much difference does their approach make? “Our aerogels are more transparent than glass because they don’t reflect — they don’t have that glare spot where the glass catches the light and reflects to you,” says Strobach.</p> <p>To Lin, a main contribution of their work is the development of general guidelines for material design, as demonstrated by Figure 4 in the slideshow above. Aided by such a “design map,” users can tailor an aerogel for a particular application. Based on the contour plots, they can determine the combinations of controllable aerogel properties — namely, density and particle size — needed to achieve a targeted haze and transmittance outcome for many applications.</p> <p><strong>Aerogels in solar thermal collectors</strong></p> <p>The researchers have already demonstrated the value of their new aerogels for solar thermal energy conversion systems, which convert sunlight into thermal energy by absorbing radiation and transforming it into heat. Current solar thermal systems can produce thermal energy at so-called intermediate temperatures — between 120 and 220 degrees Celsius — which can be used for water and space heating, steam generation, industrial processes, and more. Indeed, in 2016, U.S. consumption of thermal energy exceeded the total electricity generation from all renewable sources.</p> <p>However, state-of-the-art solar thermal systems rely on expensive optical systems to concentrate the incoming sunlight, specially designed surfaces to absorb radiation and retain heat, and costly and difficult-to-maintain vacuum enclosures to keep that heat from escaping. To date, the costs of those components have limited market adoption.</p> <p>Zhao and his colleagues thought that using a transparent aerogel layer might solve those problems. Placed above the absorber, it could let through incident solar radiation and then prevent the heat from escaping. So it would essentially replicate the natural greenhouse effect that’s causing global warming — but to an extreme degree, on a small scale, and with a positive outcome.</p> <p>To try it out, the researchers designed an aerogel-based solar thermal receiver. The device consists of a nearly “blackbody” absorber (a thin copper sheet coated with black paint that absorbs all radiant energy that falls on it), and above it a stack of optimized, low-scattering silica aerogel blocks, which efficiently transmit sunlight and suppress conduction, convection, and radiation heat losses simultaneously. The nanostructure of the aerogel is tailored to maximize its optical trans­parency while maintaining its ultralow thermal conductivity. With the aerogel present, there is no need for expensive optics, surfaces, or vacuum enclosures.</p> <p>After extensive laboratory tests of the device, the researchers decided to test it “in the field” — in this case, on the roof of an MIT building. On a sunny day in winter, they set up their device, fixing the receiver toward the south and tilted 60 degrees from horizontal to maximize solar exposure. They then monitored its performance between 11 a.m. and 1 p.m. Despite the cold ambient temperature (less than 1 C) and the presence of clouds in the afternoon, the temperature of the absorber started increasing right away and eventually stabilized above 220 C.</p> <p>To Zhao, the performance already demonstrated by the artificial greenhouse effect opens up what he calls “an exciting pathway to the promotion of solar thermal energy utilization.” Already, he and his colleagues have demonstrated that it can convert water to steam that is greater than 120 C. In collaboration with researchers at the Indian Institute of Technology Bombay, they are now exploring possible process steam applications in India and performing field tests of a low-cost, completely passive solar autoclave for sterilizing medical equipment in rural communities.</p> <p><strong>Windows and more</strong></p> <p>Strobach has been pursuing another promising application for the transparent aerogel — in windows. “In trying to make more transparent aerogels, we hit a regime in our fabrication process where we could make things smaller, but it didn’t result in a significant change in the transparency,” she says. “But it did make a significant change in the clarity,” a key feature for a window.</p> <p>The availability of an affordable, thermally insulating window would have several impacts, says Strobach. Every winter, windows in the United States lose enough energy to power over 50 million homes. That wasted energy costs the economy more than $32 billion a year and generates about 350 million tons of CO<sub>2</sub> — more than is emitted by 76 million cars. Consumers can choose high-efficiency triple-pane windows, but they’re so expensive that they’re not widely used.</p> <p>Analyses by Strobach and her colleagues showed that replacing the air gap in a conventional double-pane window with an aerogel pane could be the answer. The result could be a double-pane window that is 40 percent more insulating than traditional ones and 85 percent as insulating as today’s triple-pane windows — at less than half the price. Better still, the technology could be adopted quickly. The aerogel pane is designed to fit within the current two-pane manufacturing process that’s ubiquitous across the industry, so it could be manufactured at low cost on existing production lines with only minor changes.</p> <p>Guided by Zhao’s model, the researchers are continuing to improve the performance of their aerogels, with a special focus on increasing clarity while maintaining transparency and thermal insulation. In addition, they are considering other traditional low-cost systems that would — like the solar thermal and window technologies — benefit from sliding in an optimized aerogel to create a high-performance heat barrier that lets in abundant sunlight.</p> <p>This research was supported by the Full-Spectrum Optimized Conversion and Utilization of Sunlight program of the U.S. Department of Energy’s Advanced Research Projects Agency–Energy; the Solid-State Solar Thermal Energy Conversion Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences; and the MIT Tata Center for Technology and Design. Elise Strobach received funding from the National Science Foundation Graduate Research Fellowship Program. Lin Zhao PhD ’19 is now an optics design engineer at 3M in St. Paul, Minnesota.&nbsp;</p> <p><em>This article appears in the&nbsp;<a href="" target="_blank">Autumn 2019</a>&nbsp;issue of&nbsp;</em><a href="" target="_blank">Energy Futures</a><em>, the magazine of the MIT Energy Initiative.&nbsp;</em></p> MIT Professor Evelyn Wang (right), graduate student Elise Strobach (left), and their colleagues have been performing theoretical and experimental studies of low-cost silica aerogels optimized to serve as a transparent heat barrier in specific devices.Photo: Stuart DarschMIT Energy Initiative, Mechanical engineering, Energy, School of Engineering, Tata Center, Research, Nanoscience and nanotechnology, Materials Science and Engineering A material’s insulating properties can be tuned at will Most materials have a fixed ability to conduct heat, but applying voltage to this thin film changes its thermal properties drastically. Mon, 24 Feb 2020 14:50:23 -0500 David Chandler | MIT News Office <p>Materials whose electronic and magnetic properties can be significantly changed by applying electrical inputs form the backbone of all of modern electronics. But achieving the same kind of tunable control over the thermal conductivity of any material has been an elusive quest.</p> <p>Now, a team of researchers at MIT have made a major leap forward. They have designed a long-sought device, which they refer to as an “electrical heat valve,” that can vary the thermal conductivity on demand. They demonstrated that the material’s ability to conduct heat can be “tuned” by a factor of 10 at room temperature.</p> <p>This technique could potentially open the door to new technologies for controllable insulation in smart windows, smart walls, smart clothing, or even new ways of harvesting the energy of waste heat.&nbsp;</p> <p>The findings are reported today in the journal <em>Nature Materials</em>, in a paper by MIT professors Bilge Yildiz and Gang Chen, recent graduates Qiyang Lu PhD ’18 and Samuel Huberman PhD ’18, and six others at MIT and at Brookhaven National Laboratory.</p> <p>Thermal conductivity describes how well heat can transfer through a material. For example, it’s the reason you can easily pick up a hot frying pan with a wooden handle, because of wood’s low thermal conductivity, but you might get burned picking up a similar frying pan with a metal handle, which has high thermal conductivity.</p> <p>The researchers used a material called strontium cobalt oxide (SCO), which can be made in the form of thin films. By adding oxygen to SCO in a crystalline form called brownmillerite, thermal conductivity increased. Adding hydrogen to it caused conductivity to decrease.</p> <p>The process of adding or removing oxygen and hydrogen can be controlled simply by varying a voltage applied to the material. In essence, the process is electrochemically driven. Overall, at room temperature, the researchers found this process provided a tenfold variation in the material’s heat conduction. Such an order-of-magnitude range of electrically controllable variation has never been seen in any material before, the researchers say.</p> <p>In most known materials, thermal conductivity is invariable — wood never conducts heat well, and metals never conduct heat poorly. As such, when the researchers found that adding certain atoms into the molecular structure of a material could actually increase its thermal conductivity, it was an unexpected result. If anything, adding the extra atoms — or, more specifically, ions, atoms stripped of some electrons, or with excess electrons, to give them a net charge — should make conductivity worse (which, it turned out, was the case when adding hydrogen, but not oxygen).</p> <p>“It was a surprise to me when I saw the result,” Chen says. But after further studies of the system, he says, “now we have a better understanding” of why this unexpected phenomenon happens.</p> <p>It turns out that inserting oxygen ions into the structure of the brownmillerite SCO transforms it into what’s known as a perovskite structure — one that has an even more highly ordered structure than the original. “It goes from a low-symmetry structure to a high-symmetry one. It also reduces the amount of so-called oxygen vacancy defect sites. These together lead to its higher heat conduction,” Yildiz says.</p> <p>Heat is conducted readily through such highly ordered structures, while it tends to be scattered and dissipated by highly irregular atomic structures. Introducing hydrogen ions, by contrast, causes a more disordered structure.</p> <p>“We can introduce more order, which increases thermal conductivity, or we can introduce more disorder, which gives rise to lower conductivity. We could figure this out by performing computational modeling, in addition to our experiments,” Yildiz explains.</p> <p>While the thermal conductivity can be varied by about a factor of 10 at room temperature, at lower temperatures the variation is even greater, she adds.</p> <p>The new method makes it possible to continuously vary that degree of order, in both directions, simply by varying a voltage applied to the thin-film material. The material is either immersed in an ionic liquid (essentially a liquid salt) or in contact with a solid electrolyte, that supplies either negative oxygen ions or positive hydrogen ions (protons) into the material when the voltage is turned on. In the liquid electrolyte case, the source of oxygen and hydrogen is hydrolysis of water from the surrounding air.</p> <p>“What we have shown here is really a demonstration of the concept,” Yildiz explains. The fact that they require the use of a liquid electrolyte medium for the full range of hydrogenation and oxygenation makes this version of the system “not easily applicable to an all-solid-state device,” which would be the ultimate goal, she says. Further research will be needed to produce a more practical version. “We know there are solid-state electrolyte materials” that could theoretically be substituted for the liquids, she says. The team is continuing to explore these possibilities, and have demonstrated working devices with solid electrolytes as well.</p> <p>Chen says “there are many applications where you want to regulate heat flow.” For example, for energy storage in the form of heat, such as from a solar-thermal installation, it would be useful to have a container that could be highly insulating to retain the heat until it’s needed, but which then could be switched to be highly conductive when it comes time to retrieve that heat. “The holy grail would be something we could use for energy storage,” he says. “That’s the dream, but we’re not there yet.”</p> <p>But this finding is so new that there may also be a variety of other potential uses. This approach, Yildiz says, “could open up new applications we didn’t think of before.” And while the work was initially confined to the SCO material, “the concept is applicable to other materials, because we know we can oxygenate or hydrogenate a range of materials electrically, electrochemically” she says. In addition, although this research focused on changing the thermal properties, the same process actually has other effects as well, Chen says: “It not only changes thermal conductivity, but it also changes optical properties.”</p> <p>“This is a truly innovative and novel way for using ion insertion and extraction in solids to tune or switch thermal conductivity,” says Juergen Fleig, a professor of chemical technology and analytics at the University of Vienna, Austria, who was not involved in this work. “The measured effects (caused by two phase transitions) are not only quite large but also bi-directional, which is exciting. I’m also impressed that the processes work so well at room temperature, since such oxide materials are usually operated at much higher temperatures.”</p> <p>Yongjie Hu, an associate professor of mechanical and aerospace engineering at the University of California at Los Angeles, who also was not involved in this work, says “Active control over thermal transport is fundamentally challenging. This is a very exciting study and represents an important step to achieve the goal. It is the first report that has looked in detail at the structures and thermal properties of tri-state phases, and may open up new venues for thermal management and energy applications.”</p> <p>The research team also included Hantao Zhang, Qichen Song, Jayue Wang and Gulin Vardar at MIT, and Adrian Hunt and Iradwikanari Waluyo at Brookhaven National Laboratory in Upton, New York. The work was supported by the National Science Foundation and the U.S. Department of Energy.</p> Researchers found that strontium cobalt oxide (SCO) naturally occurs in an atomic configuration called brownmillerite (center), but when oxygen ions are added to it (right), it becomes more orderly and more heat conductive, and when hydrogen ions are added (left) it becomes less orderly and less heat conductive.Image: courtesy of the researchersMechanical engineering, Nuclear science and engineering, DMSE, Materials Science and Engineering, Research, Energy, Renewable energy, Nanoscience and nanotechnology, School of Engineering Mirrored chip could enable handheld dark-field microscopes Simple chip powered by quantum dots allows standard microscopes to visualize difficult-to-image biological organisms. Mon, 24 Feb 2020 11:29:35 -0500 Jennifer Chu | MIT News Office <p>Do a Google search for dark-field images, and you’ll discover a beautifully detailed world of microscopic organisms set in bright contrast to their midnight-black backdrops. Dark-field microscopy can reveal intricate details of translucent cells and aquatic organisms, as well as faceted diamonds and other precious stones that would otherwise appear very faint or even invisible under a typical bright-field microscope.</p> <p>Scientists generate dark-field images by fitting standard microscopes with often costly components to illumate the sample stage with a hollow, highly angled cone of light. When a translucent sample is placed under a dark-field microscope, the cone of light scatters off the sample’s features to create an image of the sample on the microscope’s camera, in bright contrast to the dark background.</p> <p>Now, engineers at MIT have developed a small, mirrored chip that helps to produce dark-field images, without dedicated expensive components. The chip is slightly larger than a postage stamp and as thin as a credit card. When placed on a microscope’s stage, the chip emits a hollow cone of light that can be used to generate detailed dark-field images of algae, bacteria, and similarly translucent tiny objects.</p> <p><img alt="Credit: Cecile Chazot" src="/sites/" style="width: 570px; height: 380px;" /></p> <p><em style="font-size: 10px;">Credit: Cecile Chazot</em></p> <p>The new optical chip can be added to standard microscopes as an affordable, downsized alternative to conventional dark-field components. The chip may also be fitted into hand-held microscopes to produce images of microorganisms in the field.</p> <p>“Imagine you’re a marine biologist,” says Cecile Chazot, a graduate student in MIT’s Department of Materials Science and Engineering. “You normally have to bring a big bucket of water into the lab to analyze. If the sample is bad, you have to go back out to collect more samples. If you have a hand-held, dark-field microscope, you can check a drop in your bucket while you’re out at sea, to see if you can go home or if you need a new bucket.”</p> <p>Chazot is the lead author of a paper detailing the team’s new design, published today in the journal <em>Nature Photonics. </em>Her co-authors are Sara Nagelberg, Igor Coropceanu, Kurt Broderick, Yunjo Kim, Moungi Bawendi, Peter So, and Mathias Kolle of MIT, along with Christopher Rowlands at Imperial College London and Maik Scherer of Papierfabrik Louisenthal GmbH in Germany.</p> <p><strong>Forever fluorescent</strong></p> <p>In an ongoing effort, members of Kolle’s lab are designing materials and devices that exhibit long-lasting “structural colors” that do not rely on dyes or pigmentation. Instead, they employ nano- and microscale structures that reflect and scatter light much like tiny prisms or soap bubbles. They can therefore appear to change colors depending on how their structures are arranged or manipulated.</p> <p>Structural color can be seen in the iridescent wings of beetles and butterflies, the feathers of birds, as well as fish scales and some flower petals. Inspired by examples of structural color in nature, Kolle has been investigating various ways to manipulate light from a microscopic, structural perspective.</p> <p>As part of this effort, he and Chazot designed a small, three-layered chip that they originally intended to use as a miniature laser. The middle layer functions as the chip’s light source, made from a polymer infused with quantum dots — tiny nanoparticles that emit light when excited with fluorescent light. Chazot likens this layer to a glowstick bracelet, where the reaction of two chemicals creates the light; except here no chemical reaction is needed — just a bit of blue light will make the quantum dots shine in bright orange and red colors.</p> <p>“In glowsticks, eventually these chemicals stop emitting light,” Chazot says. “But quantum dots are stable. If you were to make a bracelet with quantum dots, they would be fluorescent for a very long time.”</p> <p>Over this light-generating layer, the researchers placed a Bragg mirror — a structure made from alternating nanoscale layers of transparent materials, with distinctly different refractive indices, meaning the degrees to which the layers reflect incoming light.</p> <p>The Bragg mirror, Kolle says, acts as a sort of “gatekeeper” for the photons that are emitted by the quantum dots. The arrangement and thicknesses of the mirror’s layers is such that it lets photons escape up and out of the chip, but only if the light arrives at the mirror at high angles. Light arriving at lower angles is bounced back down into the chip.</p> <p>The researchers added a third feature below the light-generating layer to recycle the photons initially rejected by the Bragg mirror. This third layer is molded out of solid, transparent epoxy coated with a reflective gold film and resembles a miniature egg crate, pocked with small wells, each measuring about 4 microns in diameter.</p> <p>Chazot lined this surface with a thin layer of highly reflective gold — an optical arrangement that acts to catch any light that reflects back down from the Bragg mirror, and ping-pong that light back up, likely at a new angle that the mirror would let through. The design for this third layer was inspired by the microscopic scale structure in the wings of the <em>Papilio</em> butterfly.</p> <p>“The butterfly’s wing scales feature really intriguing egg crate-like structures with a Bragg mirror lining, which gives them their iridescent color,” Chazot says.</p> <p><strong>An optical shift</strong></p> <p>The researchers originally designed the chip as an array of miniature laser sources, thinking that its three layers could work together to create tailored laser emission patterns.</p> <p>“The initial project was to build an assembly of individually switchable coupled microscale lasing cavities,” says Kolle, associate professor of mechanical engineering at MIT. “But when Cecile made the first surfaces we realized that they had a very interesting emission profile, even without the lasing.”</p> <p>When Chazot had looked at the chip under a microscope, she noticed something curious: The chip emitted photons only at high angles forming a hollow cone of light. Turns out, the Bragg mirror had just the right layer thicknesses to &nbsp;only let photons pass through when they came at the mirror with a certain (high) angle.</p> <p>“Once we saw this hollow cone of light, we wondered: ‘Could this device be useful for something?’” Chazot says. “And the answer was: Yes!”</p> <p>As it turns out, they had incorporated the capabilities of multiple expensive, bulky dark-field microscope components into a single small chip.</p> <p>Chazot and her colleagues used well-established theoretical optical concepts to model the chip’s optical properties to optimize its performance for this newly found task. They fabricated multiple chips, each producing a hollow cone of light with a tailored angular profile. &nbsp;</p> <p>“Regardless of the microscope you’re using, among all these tiny little chips, one will work with your objective,” Chazot says.</p> <p>To test the chips, the team collected samples of seawater as well as nonpathogenic strains of the bacteria <em>E. coli</em>, and placed each sample on a chip that they set on the platform of a standard bright-field microscope. With this simple setup, they were able to produce clear and detailed dark-field images of individual bacterial cells, as well as microorganisms in seawater, which were close to invisible under bright-field illumination.</p> <p>In the near future these dark-field illumination chips could be mass-produced and tailored for even simple, high school-grade microscopes, to enable imaging of low-contrast, translucent biological samples. In combination with other work in Kolle’s lab, the chips may also be incorporated into miniaturized dark-field imaging devices for point-of-care diagnostics and bioanalytical applications in the field. &nbsp;</p> <p>“This is a wonderful story of discovery based innovation that has the potential for widespread impact in science and education through outfitting garden-variety microscopes with this technology,” says James Burgess, program manager for the Institute for Soldier Nanotechnologies, Army Research Office. “Additionally, the ability to obtain superior contrast in imaging of biological and inorganic materials under optical magnification could be incorporated into systems for identification of new biological threats and toxins in Army Medical Center laboratories and on the battlefield.”</p> <p>This research was supported, in part, by the National Science Foundation, the U.S. Army Research Office, and the National Institutes of Health.</p> Imaging, Microscopy, Materials Science and Engineering, Mechanical engineering, Quantum Dots, Bacteria, Biology, Microbes, Photonics, Nanoscience and nanotechnology, Research, DMSE, School of Engineering, National Science Foundation (NSF), National Institutes of (NIH) SENSE.nano awards seed grants in optoelectronics, interactive manufacturing The mission of SENSE.nano is to foster the development and use of novel sensors, sensing systems, and sensing solutions. Thu, 13 Feb 2020 16:40:01 -0500 MIT.nano <p>SENSE.nano has announced the recipients of the third annual SENSE.nano seed grants. This year’s grants serve to advance innovations in sensing technologies for augmented and virtual realities (AR/VR) and advanced manufacturing systems.</p> <p>A center of excellence powered by MIT.nano, SENSE.nano received substantial interest in its 2019 call for proposals, making for stiff competition. Proposals were reviewed and evaluated by a committee consisting of industry and academia thought-leaders and were selected for funding following significant discussion. Ultimately, two projects were awarded $75,000 each to further research related to detecting movement in molecules and monitoring machine health.&nbsp;</p> <p>“SENSE.nano strives to&nbsp;convey the breadth and depth of sensing research at MIT," says Brian Anthony, co-leader of SENSE.nano, associate director of MIT.nano, and a principal&nbsp;research scientist in the Department of Mechanical Engineering. “As we work to grow SENSE.nano’s research footing and to attract partners, it is encouraging to know that so much important research — in sensors; sensor systems; and sensor science, engineering — is taking place at the Institute.”</p> <p>The projects receiving grants are:</p> <p><strong>P. Donald Keathley and Karl Berggren: Nanostructured optical-field samplers for visible to near-infrared time-domain spectroscopy</strong></p> <p>Research Scientist Phillip “Donnie” Keathley and Professor Karl Berggren from the Department of Electrical Engineering and Computer Science are developing a field-sampling technique using nanoscale structures and light waves to sense vibrational motion of molecules. Keathley is a member of Berggren’s quantum nanostructures and nanofabrication group in the Research Laboratory of Electronics (RLE). The two are investigating an all-on-chip nanoantenna device for sampling weak sub-femtojoule-level electronic fields, in the near-infrared and visible spectrums.</p> <p>Current technology for sampling these spectra of optical energy requires a large apparatus — there is no compact device with enough sensitivity to detect the low-energy signals. Keathley and Berggren propose using plasmonic nanoantennas for measuring low-energy pulses. This technology could have significant impacts on the medical and food-safety industries by revolutionizing the accurate detection and identification of chemicals and bio-chemicals.</p> <p><strong>Jeehwan Kim: Interactive manufacturing enabled by simultaneous sensing and recognition</strong></p> <p>Jeehwan Kim, associate professor with a dual appointment in mechanical engineering and materials science and engineering, proposes an ultra-sensitive sensor system using neuromorphic chips to improve advanced manufacturing through real-time monitoring of machines. Machine failures compromise productivity and cost. Sensors that can instantly process data to provide real-time feedback would be a valuable tool for preventive maintenance of factory machines.</p> <p>Kim’s group, also part of RLE, aims to develop single-crystalline gallium nitride sensors that, when connected to AI chips, will create a feedback loop with the factory machines. Failure patterns would be recognized by the AI hardware, creating an intelligent manufacturing system that can predict and prevent failures. These sensors will have the sensitivity to navigate noisy factory environments, be small enough to form dense arrays, and have the power efficiency to be used on a large number of manufacturing machines.</p> <p>The mission of SENSE.nano is to foster the development and use of novel sensors, sensing systems, and sensing solutions in order to provide previously unimaginable insight into the condition of our world. Two new calls for seed grant proposals will open later this year in conjunction with the Immersion Lab NCSOFT collaboration and then with the SENSE.nano 2020 symposium.</p> <p>In addition to seed grants and the annual conference, SENSE.nano recently launched Talk SENSE — a monthly series for MIT students to further engage with these topics and connect with experts working in sensing technologies.</p> A center of excellence powered by MIT.nano, SENSE.nano received substantial interest in its 2019 call for proposals, making for stiff competition.Photo: David SellaMIT.nano, Mechanical engineering, Electrical engineering and computer science (EECS), Materials Science and Engineering, Nanoscience and nanotechnology, Awards, honors and fellowships, Augmented and virtual reality, Computer science and technology, Artificial intelligence, Research, Funding, Grants, Sensors, School of Engineering, Research Laboratory of Electronics “Sensorized” skin helps soft robots find their bearings Flexible sensors and an artificial intelligence model tell deformable robots how their bodies are positioned in a 3D environment. Wed, 12 Feb 2020 23:59:59 -0500 Rob Matheson | MIT News Office <p>For the first time, MIT researchers have enabled a soft robotic arm to understand its configuration in 3D space, by leveraging only motion and position data from its own “sensorized” skin.</p> <p>Soft robots constructed from highly compliant materials, similar to those found in living organisms, are being championed as safer, and more adaptable, resilient, and bioinspired alternatives to traditional rigid robots. But giving autonomous control to these deformable robots is a monumental task because they can move in a virtually infinite number of directions at any given moment. That makes it difficult to train planning and control models that drive automation.</p> <p>Traditional methods to achieve autonomous control use large systems of multiple motion-capture cameras that provide the robots feedback about 3D movement and positions. But those are impractical for soft robots in real-world applications.</p> <p>In a paper being published in the journal <em>IEEE Robotics and Automation Letters</em>, the researchers describe a system of soft sensors that cover a robot’s body to provide “proprioception” — meaning awareness of motion and position of its body. That feedback runs into a novel deep-learning model that sifts through the noise and captures clear signals to estimate the robot’s 3D configuration. The researchers validated their system on a soft robotic arm resembling an elephant trunk, that can predict its own position as it autonomously swings around and extends.</p> <p>The sensors can be fabricated using off-the-shelf materials, meaning any lab can develop their own systems, says Ryan Truby, a postdoc in the MIT Computer Science and Artificial Laboratory (CSAIL) who is co-first author on the paper along with CSAIL postdoc Cosimo Della Santina.</p> <p>“We’re sensorizing soft robots to get feedback for control from sensors, not vision systems, using a very easy, rapid method for fabrication,” he says. “We want to use these soft robotic trunks, for instance, to orient and control themselves automatically, to pick things up and interact with the world. This is a first step toward that type of more sophisticated automated control.”</p> <p>One future aim is to help make artificial limbs that can more dexterously handle and manipulate objects in the environment. “Think of your own body: You can close your eyes and reconstruct the world based on feedback from your skin,” says co-author Daniela Rus, director of CSAIL and the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science. “We want to design those same capabilities for soft robots.”</p> <p><strong>Shaping soft sensors</strong></p> <p>A longtime goal in soft robotics has been fully integrated body sensors. Traditional rigid sensors detract from a soft robot body’s natural compliance, complicate its design and fabrication, and can cause various mechanical failures. Soft-material-based sensors are a more suitable alternative, but require specialized materials and methods for their design, making them difficult for many robotics labs to fabricate and integrate in soft robots.</p> <p>While working in his CSAIL lab one day looking for inspiration for sensor materials, Truby made an interesting connection. “I found these sheets of conductive materials used for electromagnetic interference shielding, that you can buy anywhere in rolls,” he says. These materials have “piezoresistive” properties, meaning they change in electrical resistance when strained. Truby realized they could make effective soft sensors if they were placed on certain spots on the trunk. As the sensor deforms in response to the trunk’s stretching and compressing, its electrical resistance is converted to a specific output voltage. The voltage is then used as a signal correlating to that movement.</p> <p>But the material didn’t stretch much, which would limit its use for soft robotics. Inspired by kirigami —&nbsp;a variation of origami that includes making cuts in a material — Truby designed and laser-cut rectangular strips of conductive silicone sheets into various patterns, such as rows of tiny holes or crisscrossing slices like a chain link fence. That made them far more flexible, stretchable, “and beautiful to look at,” Truby says.</p> <p><img alt="" src="/sites/" style="width: 500px; height: 281px;" /></p> <p><img alt="" src="/sites/" style="width: 500px; height: 281px;" /></p> <p><em style="font-size: 10px;">Credit: Ryan L. Truby, MIT&nbsp;CSAIL</em></p> <p>The researchers’ robotic trunk comprises three segments, each with four fluidic actuators (12 total) used to move the arm. They fused one sensor over each segment, with each sensor covering and gathering data from one embedded actuator in the soft robot. They used “plasma bonding,” a technique that energizes a surface of a material to make it bond to another material. It takes roughly a couple hours to shape dozens of sensors that can be bonded to the soft robots using a handheld plasma-bonding device.</p> <p><img alt="" src="/sites/" style="width: 500px; height: 281px;" /></p> <p><span style="font-size:10px;"><em>Credit: Ryan L. Truby, MIT&nbsp;CSAIL</em></span></p> <p><strong>“Learning” configurations</strong></p> <p>As hypothesized, the sensors did capture the trunk’s general movement. But they were really noisy. “Essentially, they’re nonideal sensors in many ways,” Truby says. “But that’s just a common fact of making sensors from soft conductive materials. Higher-performing and more reliable sensors require specialized tools that most robotics labs do not have.”</p> <p>To estimate the soft robot’s configuration using only the sensors, the researchers built a deep neural network to do most of the heavy lifting, by sifting through the noise to capture meaningful feedback signals. The researchers developed a new model to kinematically describe the soft robot’s shape that vastly reduces the number of variables needed for their model to process.</p> <p>In experiments, the researchers had the trunk swing around and extend itself in random configurations over approximately an hour and a half. They used the traditional motion-capture system for ground truth data. In training, the model analyzed data from its sensors to predict a configuration, and compared its predictions to that ground truth data which was being collected simultaneously. In doing so, the model “learns” to map signal patterns from its sensors to real-world configurations. Results indicated, that for certain and steadier configurations, the robot’s estimated shape matched the ground truth.</p> <p>Next, the researchers aim to explore new sensor designs for improved sensitivity and to develop new models and deep-learning methods to reduce the required training for every new soft robot. They also hope to refine the system to better capture the robot’s full dynamic motions.</p> <p>Currently, the neural network and sensor skin are not sensitive to capture subtle motions or dynamic movements. But, for now, this is an important first step for learning-based approaches to soft robotic control, Truby says: “Like our soft robots, living systems don’t have to be totally precise. Humans are not precise machines, compared to our rigid robotic counterparts, and we do just fine.”</p> MIT researchers have created a “sensorized” skin, made with kirigami-inspired sensors, that gives soft robots greater awareness of the motion and position of their bodies.Ryan L. Truby, MIT CSAILResearch, Computer science and technology, Algorithms, Robots, Robotics, Soft robotics, Design, Machine learning, Materials Science and Engineering, Computer Science and Artificial Intelligence Laboratory (CSAIL), Electrical Engineering & Computer Science (eecs), School of Engineering Researchers develop a roadmap for growth of new solar cells Starting with higher-value niche markets and then expanding could help perovskite-based solar panels become competitive with silicon. Thu, 06 Feb 2020 10:57:11 -0500 David L. Chandler | MIT News Office <p>Materials called perovskites show strong potential for a new generation of solar cells, but they’ve had trouble gaining traction in a market dominated by silicon-based solar cells. Now, a study by researchers at MIT and elsewhere outlines a roadmap for how this promising technology could move from the laboratory to a significant place in the global solar market.</p> <p>The “technoeconomic” analysis shows that by starting with higher-value niche markets and gradually expanding, solar panel manufacturers could avoid the very steep initial capital costs that would be required to make perovskite-based panels directly competitive with silicon for large utility-scale installations at the outset. Rather than making a prohibitively expensive initial investment, of hundreds of millions or even billions of dollars, to build a plant for utility-scale production, the team found that starting with more specialized applications could be accomplished for more realistic initial capital investment on the order of $40 million.</p> <p>The results are described in a paper in the journal <em>Joule</em> by MIT postdoc Ian Mathews, research scientist Marius Peters, professor of mechanical engineering Tonio Buonassisi, and five others at MIT, Wellesley College, and Swift Solar Inc.</p> <p>Solar cells based on perovskites — a broad category of compounds characterized by a certain arrangement of their molecular structure — could provide dramatic improvements in solar installations. Their constituent materials are inexpensive, and they could be manufactured in a roll-to-roll process like printing a newspaper, and printed onto lightweight and flexible backing material. This could greatly reduce costs associated with transportation and installation, although they still require further work to improve their durability. Other promising new solar cell materials are also under development in labs around the world, but none has yet made inroads in the marketplace.</p> <p>“There have been a lot of new solar cell materials and companies launched over the years,” says Mathews, “and yet, despite that, silicon remains the dominant material in the industry and has been for decades.”</p> <p>Why is that the case? “People have always said that one of the things that holds new technologies back is that the expense of constructing large factories to actually produce these systems at scale is just too much,” he says. “It’s difficult for a startup to cross what’s called ‘the valley of death,’ to raise the tens of millions of dollars required to get to the scale where this technology might be profitable in the wider solar energy industry.”</p> <p>But there are a variety of more specialized solar cell applications where the special qualities of perovskite-based solar cells, such as their light weight, flexibility, and potential for transparency, would provide a significant advantage, Mathews says. By focusing on these markets initially, a startup solar company could build up to scale gradually, leveraging the profits from the premium products to expand its production capabilities over time.</p> <p>Describing the literature on perovskite-based solar cells being developed in various labs, he says, “They’re claiming very low costs. But they’re claiming it once your factory reaches a certain scale. And I thought, we’ve seen this before — people claim a new photovoltaic material is going to be cheaper than all the rest and better than all the rest. That’s great, except we need to have a plan as to how we actually get the material and the technology to scale.”</p> <p>As a starting point, he says, “We took the approach that I haven’t really seen anyone else take: Let’s actually model the cost to manufacture these modules as a function of scale. So if you just have 10 people in a small factory, how much do you need to sell your solar panels at in order to be profitable? And once you reach scale, how cheap will your product become?”</p> <p>The analysis confirmed that trying to leap directly into the marketplace for rooftop solar or utility-scale solar installations would require very large upfront capital investment, he says. But “we looked at the prices people might get in the internet of things, or the market in building-integrated photovoltaics. People usually pay a higher price in these markets because they’re more of a specialized product. They’ll pay a little more if your product is flexible or if the module fits into a building envelope.” Other potential niche markets include self-powered microelectronics devices.</p> <p>Such applications would make the entry into the market feasible without needing massive capital investments. “If you do that, the amount you need to invest in your company is much, much less, on the order of a few million dollars instead of tens or hundreds of millions of dollars, and that allows you to more quickly develop a profitable company,” he says.</p> <p>“It’s a way for them to prove their technology, both technically and by actually building and selling a product and making sure it survives in the field,” Mathews says, “and also, just to prove that you can manufacture at a certain price point.”</p> <p>Already, there are a handful of startup companies working to try to bring perovskite solar cells to market, he points out, although none of them yet has an actual product for sale. The companies have taken different approaches, and some seem to be embarking on the kind of step-by-step growth approach outlined by this research, he says. “Probably the company that’s raised the most money is a company called Oxford PV, and they’re looking at tandem cells,” which incorporate both silicon and perovskite cells to improve overall efficiency. Another company is one started by Joel Jean PhD ’17 (who is also a co-author of this paper) and others, called Swift Solar, which is working on flexible perovskites. And there’s a company called Saule Technologies, working on printable perovskites.</p> <p>Mathews says the kind of technoeconomic analysis the team used in its study could be applied to a wide variety of other new energy-related technologies, including rechargeable batteries and other storage systems, or other types of new solar cell materials.</p> <p>“There are many scientific papers and academic studies that look at how much it will cost to manufacture a technology once it’s at scale,” he says. “But very few people actually look at how much does it cost at very small scale, and what are the factors affecting economies of scale? And I think that can be done for many technologies, and it would help us accelerate how we get innovations from lab to market.”</p> <p>The research team also included MIT alumni Sarah Sofia PhD ’19 and Sin Cheng Siah PhD ’15, Wellesley College student Erica Ma, and former MIT postdoc Hannu Laine. The work was supported by the European Union’s Horizon 2020 research and innovation program, the Martin Family Society for Fellows of Sustainability, the U.S. Department of Energy, Shell, through the MIT Energy Initiative, and the Singapore-MIT Alliance for Research and Technology.</p> Perovskites, a family of materials defined by a particular kind of molecular structure as illustrated here, have great potential for new kinds of solar cells. A new study from MIT shows how these materials could gain a foothold in the solar marketplace.Image: Christine Daniloff, MITResearch, School of Engineering, Energy, Solar, Nanoscience and nanotechnology, Materials Science and Engineering, Mechanical engineering, National Science Foundation (NSF), Renewable energy, Alternative energy, Sustainability, Artificial intelligence, Machine learning, MIT Energy Initiative, Singapore-MIT Alliance for Research and Technology (SMART) Engineers mix and match materials to make new stretchy electronics Next-generation devices made with new “peel and stack” method may include electronic chips worn on the skin. Wed, 05 Feb 2020 13:00:00 -0500 Jennifer Chu | MIT News Office <p>At the heart of any electronic device is a cold, hard computer chip, covered in a miniature city of transistors and other semiconducting elements. Because computer chips are rigid, the electronic devices that they power, such as our smartphones, laptops, watches, and televisions, are similarly inflexible.</p> <p>Now a process developed by MIT engineers may be the key to manufacturing flexible electronics with multiple functionalities in a cost-effective way.</p> <p>The process is called&nbsp; “remote epitaxy” and involves growing thin films of semiconducting material on a large, thick wafer of the same material, which is covered in an intermediate layer of graphene. Once the researchers grow a semiconducting film, they can peel it away from the graphene-covered wafer and then reuse the wafer, which itself can be expensive depending on the type of material it’s made from. In this way, the team can copy and peel away any number of thin, flexible semiconducting films, using the same underlying wafer.</p> <p>In a paper published today in the journal <em>Nature</em>, the researchers demonstrate that they can use remote epitaxy to produce freestanding films of any functional material. More importantly, they can stack films made from these different materials, to produce flexible, multifunctional electronic devices.</p> <p>The researchers expect that the process could be used to produce stretchy electronic films for a wide variety of uses, including virtual reality-enabled contact lenses, solar-powered skins that mold to the contours of your car, electronic fabrics that respond to the weather, and other flexible electronics that seemed until now to be the stuff of Marvel movies.</p> <p>“You can use this technique to mix and match any semiconducting material to have new device functionality, in one flexible chip,” says Jeehwan Kim, an associate professor of mechanical engineering at MIT. “You can make electronics in any shape.”</p> <p>Kim’s co-authors include Hyun S. Kum, Sungkyu Kim, Wei Kong, Kuan Qiao, Peng Chen, Jaewoo Shim, Sang-Hoon Bae, Chanyeol Choi, Luigi Ranno, Seungju Seo, Sangho Lee, Jackson Bauer, and Caroline Ross from MIT, along with collaborators from the University of Wisconsin at Madison, Cornell University, the University of Virginia, Penn State University, Sun Yat-Sen University, and the Korea Atomic Energy Research Institute.</p> <div class="cms-placeholder-content-video"></div> <p><strong>Buying time</strong></p> <p>Kim and his colleagues reported their <a href="">first results</a> using remote epitaxy in 2017. Then, they were able to produce thin, flexible films of semiconducting material by first placing a layer of graphene on a thick, expensive wafer made from a combination of exotic metals. They flowed atoms of each metal over the graphene-covered wafer and found the atoms formed a film on top of the graphene, in the same crystal pattern as the underlying wafer. The graphene provided a nonstick surface from which the researchers could peel away the new film, leaving the graphene-covered wafer, which they could reuse.&nbsp;</p> <p>In 2018, the team showed that they could use remote epitaxy to make semiconducting materials from metals in groups 3 and 5 of the periodic table, but not from group 4. The reason, they found, <a href="">boiled down to polarity</a>, or the respective charges between the atoms flowing over graphene and the atoms in the underlying wafer.</p> <p>Since this realization, Kim and his colleagues have tried a number of increasingly exotic semiconducting combinations. As reported in this new paper, the team used remote epitaxy to make flexible semiconducting films from complex oxides — chemical compounds made from oxygen and at least two other elements. Complex oxides are known to have a wide range of electrical and magnetic properties, and some combinations can generate a current when physically stretched or exposed to a magnetic field.</p> <p>Kim says the ability to manufacture flexible films of complex oxides could open the door to new energy-havesting devices, such as sheets or coverings that stretch in response to vibrations and produce electricity as a result. Until now, complex oxide materials have only been manufactured on rigid, millimeter-thick wafers, with limited flexibility and therefore limited energy-generating potential.</p> <p>The researchers did have to tweak their process to make complex oxide films. They initially found that when they tried to make a complex oxide such as strontium titanate (a compound of strontium, titanium, and three oxygen atoms), the oxygen atoms that they flowed over the graphene tended to bind with the graphene’s carbon atoms, etching away bits of graphene instead of following the underlying wafer’s pattern and binding with strontium and titanium. As a surprisingly simple fix, the researchers added a second layer of graphene.</p> <p>“We saw that by the time the first layer of graphene is etched off, oxide compounds have already formed, so elemental oxygen, once it forms these desired compounds, does not interact as heavily with graphene,” Kim explains. “So two layers of graphene buys some time for this compound to form.”</p> <p><strong>Peel and stack</strong></p> <p>The team used their newly tweaked process to make films from multiple complex oxide materials, peeling off each 100-nanometer-thin layer as it was made. They were also able to stack together layers of different complex oxide materials and effectively glue them together by heating them slightly, producing a flexible, multifunctional device.</p> <p>“This is the first demonstration of stacking multiple nanometers-thin membranes like LEGO blocks, which has been impossible because all functional electronic materials exist in a thick wafer form,” Kim says.</p> <p>In one experiment, the team stacked together films of two different complex oxides: cobalt ferrite, known to expand in the presence of a magnetic field, and PMN-PT, a material that generates voltage when stretched. When the researchers exposed the multilayer film to a magnetic field, the two layers worked together to both expand and produce a small electric current.&nbsp;</p> <p>The results demonstrate that remote epitaxy can be used to make flexible electronics from a combination of materials with different functionalities, which previously were difficult to combine into one device. In the case of cobalt ferrite and PMN-PT, each material has a different crystalline pattern. Kim says that traditional epitaxy techniques, which grow materials at high temperatures on one wafer, can only combine materials if their crystalline patterns match. He says that with remote epitaxy, researchers can make any number of different films, using different, reusable wafers, and then stack them together, regardless of their crystalline pattern.</p> <p>“The big picture of this work is, you can combine totally different materials in one place together,” Kim says. “Now you can imagine a thin, flexible device made from layers that include a sensor, computing system, a battery, a solar cell, so you could have a flexible, self-powering, internet-of-things stacked chip.”</p> <p>The team is exploring various combinations of semiconducting films and is working on developing prototype devices, such as something Kim is calling an “electronic tattoo” — a flexible, transparent chip that can attach and conform to a person’s body to sense and wirelessly relay vital signs such as temperature and pulse.</p> <p>“We can now make thin, flexible, wearable electronics with the highest functionality,” Kim says. “Just peel off and stack up.”</p> <p>The research was the outcome of close collaboration between the researchers at MIT and at the University of Wisconsin at Madison, which was supported by the Defense Advanced Research Projects Agency.</p> With a new technique, MIT researchers can peel and stack thin films of metal oxides — chemical compounds that can be designed to have unique magnetic and electronic properties. The films can be mixed and matched to create multi-functional, flexible electronic devices, such as solar-powered skins and electronic fabrics.Image: Felice Frankelelectronics, Graphene, Mechanical engineering, Research, Nanoscience and nanotechnology, Materials Science and Engineering, DMSE, School of Engineering New electrode design may lead to more powerful batteries An MIT team has devised a lithium metal anode that could improve the longevity and energy density of future batteries. Mon, 03 Feb 2020 10:59:59 -0500 David L. Chandler | MIT News Office <p>New research by engineers at MIT and elsewhere could lead to batteries that can pack more power per pound and last longer, based on the long-sought goal of using pure lithium metal as one of the battery’s two electrodes, the anode. &nbsp;</p> <p>The new electrode concept comes from the laboratory of Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering and professor of materials science and engineering. It is described today in the journal <em>Nature</em>, in a paper co-authored by Yuming Chen and Ziqiang Wang at MIT, along with 11 others at MIT and in Hong Kong, Florida, and Texas.</p> <p>The design is part of a concept for developing safe all-solid-state batteries, dispensing with the liquid or polymer gel usually used as the electrolyte material between the battery’s two electrodes. An electrolyte allows lithium ions to travel back and forth during the charging and discharging cycles of the battery, and an all-solid version could be safer than liquid electrolytes, which have high volatilility and have been the source of explosions in lithium batteries.</p> <p>“There has been a lot of work on solid-state batteries, with lithium metal electrodes and solid electrolytes,” Li says, but these efforts have faced a number of issues.</p> <p>One of the biggest problems is that when the battery is charged up, atoms accumulate inside the lithium metal, causing it to expand. The metal then shrinks again during discharge, as the battery is used. These repeated changes in the metal’s dimensions, somewhat like the process of inhaling and exhaling, make it difficult for the solids to maintain constant contact, and tend to cause the solid electrolyte to fracture or detach.</p> <p>Another problem is that none of the proposed solid electrolytes are truly chemically stable while in contact with the highly reactive lithium metal, and they tend to degrade over time.</p> <p>Most attempts to overcome these problems have focused on designing solid electrolyte materials that are absolutely stable against lithium metal, which turns out to be difficult.&nbsp; Instead, Li and his team adopted an unusual design that utilizes two additional classes of solids, “mixed ionic-electronic conductors” (MIEC) and “electron and Li-ion insulators” (ELI), which are absolutely chemically stable in contact with lithium metal.</p> <p>The researchers developed a three-dimensional nanoarchitecture in the form of a honeycomb-like array of hexagonal MIEC tubes, partially infused with the solid lithium metal to form one electrode of the battery, but with extra space left inside each tube. When the lithium expands in the charging process, it flows into the empty space in the interior of the tubes, moving like a liquid even though it retains its solid crystalline structure. This flow, entirely confined inside the honeycomb structure, relieves the pressure from the expansion caused by charging, but without changing the electrode’s outer dimensions or the boundary between the electrode and electrolyte. The other material, the ELI, serves as a crucial mechanical binder between the MIEC walls and the solid electrolyte layer.</p> <p>“We designed this structure that gives us three-dimensional electrodes, like a honeycomb,” Li says. The void spaces in each tube of the structure allow the lithium to “creep backward” into the tubes, “and that way, it doesn’t build up stress to crack the solid electrolyte.” The expanding and contracting lithium inside these tubes moves in and out, sort of like a car engine’s pistons inside their cylinders. Because these structures are built at nanoscale dimensions (the tubes are about 100 to 300 nanometers in diameter, and tens of microns in height), the result is like “an engine with 10 billion pistons, with lithium metal as the working fluid,” Li says.</p> <p>Because the walls of these honeycomb-like structures are made of chemically stable MIEC, the lithium never loses electrical contact with the material, Li says. Thus, the whole solid battery can remain mechanically and chemically stable as it goes through its cycles of use. The team has proved the concept experimentally, putting a test device through 100 cycles of charging and discharging without producing any fracturing of the solids.</p> <p><img alt="" src="/sites/" style="width: 500px; height: 440px;" /></p> <p><em><span style="font-size:10px;">Reversible Li metal plating and stripping in a carbon tubule with&nbsp;an inner diameter of 100nm. Courtesy of the researchers.</span></em></p> <p>Li says that though many other groups are working on what they call solid batteries, most of those systems actually work better with some liquid electrolyte mixed with the solid electrolyte material. “But in our case,” he says, “it’s truly all solid. There is no liquid or gel in it of any kind.”&nbsp;&nbsp;</p> <p>The new system could lead to safe anodes that weigh only a quarter as much as their conventional counterparts in lithium-ion batteries, for the same amount of storage capacity. If combined with new concepts for lightweight versions of the other electrode, the cathode, this work could lead to substantial reductions in the overall weight of lithium-ion batteries. For example, the team hopes it could lead to cellphones that could be charged just once every three days, without making the phones any heavier or bulkier.</p> <p>One new concept for a lighter cathode was described by another team led by Li, in a paper that appeared last month in the journal <em>Nature Energy</em>, co-authored by MIT postdoc Zhi Zhu and graduate student Daiwei Yu. The material would reduce the use of nickel and cobalt, which are expensive and toxic and used in present-day cathodes. The new cathode does not rely only on the capacity contribution from these transition-metals in battery cycling. Instead, it would rely more on the redox capacity of oxygen, which is much lighter and more abundant. But in this process the oxygen ions become more mobile, which can cause them to escape from the cathode particles. The researchers used a high-temperature surface treatment with molten salt to produce a protective surface layer on particles of manganese- and lithium-rich metal-oxide, so the amount of oxygen loss is drastically reduced.</p> <p>Even though the surface layer is very thin, just 5 to 20 nanometers thick on a 400 nanometer-wide particle, it provides good protection for the underlying material. “It’s almost like immunization,” Li says, against the destructive effects of oxygen loss in batteries used at room temperature. The present versions provide at least a 50 percent improvement in the amount of energy that can be stored for a given weight, with much better cycling stability.</p> <p>The team has only built small lab-scale devices so far, but “I expect this can be scaled up very quickly,” Li says. The materials needed, mostly manganese, are significantly cheaper than the nickel or cobalt used by other systems, so these cathodes could cost as little as a fifth as much as the conventional versions.</p> <p>The research teams included researchers from MIT, Hong Kong Polytechnic University, the University of Central Florida, the University of Texas at Austin, and Brookhaven National Laboratories in Upton, New York. The work was supported by the National Science Foundation.</p> New research by engineers at MIT and elsewhere could lead to batteries that can pack more power per pound and last longer.Credit: MIT NewsResearch, Research Laboratory of Electronics, Nuclear science and engineering, School of Engineering, Materials Science and Engineering, DMSE, Batteries, Energy storage, Energy, National Science Foundation (NSF), Nanoscience and nanotechnology A new facet for germanium MIT researchers grow perfectly shaped germanium tunnels on silicon oxide with controllable length. Fri, 31 Jan 2020 15:00:01 -0500 Denis Paiste | Materials Research Laboratory <p>Although silicon is the workhorse of the semiconductor industry, forming the basis for computer chips, camera sensors, and other everyday electronic devices, researchers and manufacturers add other materials, such as germanium, to boost silicon chip processing speed, cut power consumption, and create new functions, such as photonic connections that use light instead of electrical current to transfer data.</p> <p>Researchers have known for about a decade that dome-shaped empty spaces form in germanium when it is grown on top of silicon patterned with a dielectric material, such as silicon oxide or silicon nitride, that masks part of the silicon base. Now, MIT researchers have discovered a method to predict and control the length of tunnels in solid germanium by growing it on silicon oxide strips on top of silicon. These tunnels have potential to be used as light channels for silicon photonics or liquid channels for microfluidic devices.</p> <p>“We found a tunnel or cavity on top of the silicon dioxide which is between the germanium and the silicon dioxide, and we can vary the length of the tunnel depending on the length of the oxide,” says&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Rui-Tao Wen</a>, a former MIT postdoc and first author of a recent&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">paper</a>&nbsp;in&nbsp;<em>Nano Letters</em>. Wen is now an assistant professor of materials science and engineering at the Southern University of Science and Technology in Shenzhen, China.</p> <p>The researchers used a two-step growth process, which first puts down a layer of germanium at a relatively lower temperature, then adds another germanium layer at a relatively higher temperature. The germanium layers have difficulty bonding directly to the silicon oxide strips. “The major discovery was that you form these cavities or tunnels, and they’re actually reconfiguring during growth or annealing,” says&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Jurgen Michel</a>, Materials Research Laboratory senior research scientist and senior lecturer in the Department of Materials Science and Engineering. “The reconfiguration internally is a basic scientific phenomenon that I don’t think anybody would have expected.”</p> <p><strong>Evolving over time</strong></p> <p>During their experiments, which took a year to carry out, first author Wen analyzed cross-sections of the germanium-silicon oxide material with a transmission electron microscope (TEM), capturing images at multiple points in time during its formation. Before actually analyzing their results, the researchers expected that once tunnels formed they would stay the same shape throughout the process. Instead, they found a large amount of material is reconfigured within that space as the material evolves over time. “This is something that nobody has observed yet, that you can actually get this, what we call internal reconfiguration of material,” Michel says.</p> <p>“So for instance, the tunnel gets larger, some of the connected material completely disappears, and the tunnel surfaces are perfect in terms that they are atomically flat,” Michel says. “They form actually what are called facets, which are certain crystallographic germanium orientations.”</p> <p>The fine resolution that Wen obtained with TEM images unexpectedly showed these internal surfaces appear to have perfect surfaces. “Normally, if we do epitaxial growth of germanium on silicon, we will find very many dislocations,” Wen says. “There are none of those defects on top of the tunnels. It’s not like materials we used to have, which have a lot of dislocations in germanium layers. This one is a perfect single crystal.” Co-author&nbsp;<a dir="ltr" href=";ts=1377104806" rel="noopener" target="_blank">Baoming Wang</a>&nbsp;prepared the TEM samples. Wang is a postdoc in Professor Carl V. Thompson’s Materials for Micro and Nano Systems research group.</p> <p>During the growth process, which is called selective epitaxy growth, a gas containing a compound of germanium and hydrogen (germane) flows into an ultra-high vacuum chemical vapor deposition chamber. At first, the germanium deposits on the silicon, then it slowly overgrows the silicon oxide strips, forming an archway-shaped tunnel centered directly over the oxide strips.</p> <p>Wen patterned silicon oxide strips up to 2 centimeters in length (about three-quarters of an inch) on a 6-inch (about 15 cm) silicon wafer with tunnels covering the entire length of the strip. The strips themselves ranged in size from a width of 350 to 750 nanometers and lengths of 2 microns to 2 cm. The only limit to tunnel length appears to be the size of the silicon base layer, Michel suggests. “We see that the ends of that strip are partially covered with germanium, but then the tunnel length increases with strip length. And that’s a linear process,” he says.</p> <p><strong>Growth conditions</strong></p> <p>In these experiments, the pressure in the tunnels was about 10 millibars, which is about 100 times weaker than sea-level atmospheric pressure. Suggesting a mechanism for how the tunnels form, Michel explains that the germanium cannot form a stable germanium oxide directly on top of the silicon oxide in the high temperature, ultra-high vacuum environment, so the process slowly consumes the oxide. “You lose some of the oxide thickness during growth, but the area will stay clear,” he says. Rather than being empty, the tunnels are likely occupied by hydrogen gas, which is present because the germane gas separates into its germanium and hydrogen components.</p> <p>Another surprising finding was that as the germanium spreads over the silicon oxide strips, it does so unevenly at first, covering the far ends of the strip and then moving toward the centers of the strips. But as this process continues, the uncovered area of the silicon oxide shrinks from an oval shape to a circle, after which the germanium evenly spreads over the remaining uncovered area.</p> <p>“The effect of the length of the oxide stripe on tunnel formation is surprising and deserves further explanation, both for theoretical understanding and for possible applications,” says Ted Kamins, an adjunct professor of electrical engineering at Stanford University, who was not involved in this research. “The end effects might be useful for introducing liquids or gases into the tunnels. Overgrowth only from the ends of the oxide stripe is also unexpected for four-fold symmetric materials, such as Si (silicon) and Ge (germanium).”</p> <p>“If controllable and reproducible, the technique might be applied to photonics, where an abrupt change of refractive index can help guide light, and to microfluidics integrated onto a silicon chip,” Kamins says.</p> <p>“The results are absolutely fascinating and shocking — my jaw drops when going through the electron microscopy photos,” says Jifeng Liu, an associate professor of engineering at Dartmouth College, who was not involved in this research. “Imagine all the pillars in the middle of the Longfellow Bridge gradually and spontaneously migrate to the banks, and one day you find the entire bridge completely suspended in the middle! This would be analogous to what has been reported in this paper on microscopic scale.”</p> <p>As a postdoc at MIT from 2007 to 2010, Liu worked on the&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">first germanium laser</a>&nbsp;and the first germanium-silicon electroabsorption modulator with Jurgen Michel and&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Lionel C. Kimerling</a>, the Thomas Lord Professor of Materials Science and Engineering. At Dartmouth, Liu continues research on germanium and other materials such as germanium-tin compounds for photonic integration on silicon platforms.</p> <p>“I hope these beautiful and shocking results also remind all of us about the central importance of hands-on experimental research and training, even in an emerging age of artificial intelligence and machine learning — you simply cannot calculate and predict everything, not even in a material growth process that has been studied for three decades,” Liu says.</p> <p>Kamins notes that “This experimental study produced a significant amount of data that should be used to gain an understanding of the mechanisms. Then, the technique can be assessed for its practicality for applications.”</p> <p>Michel notes that the although the findings about tunnel formation were demonstrated in a specific growth system of germanium on silicon using silicon oxide to pattern growth, these results also should apply to similar growth systems based on combinations of elements such as aluminum, gallium, and arsenic or indium and phosphorus that are called III-V semiconductor materials. “Any kind of growth system where you have this selective growth, you should be able to generate tunnels and voids,” Michel says.</p> <p>Additional experiments will need to be carried out to see if this process can produce devices for microfluidics, photonics, or possibly passing light and liquid through together. “It’s a very first step toward applications,” Michel says.</p> <p>This research was supported by the National Science Foundation.</p> MIT researchers have discovered a method to predict and control the length of tunnels in solid germanium by laterally growing it over silicon oxide strips (shown in yellow) on top of silicon (green), depicted from left to right. Germanium, shown in purple, smoothly covers the silicon but forms voids and tunnels (lighter shade of purple) where germanium and silicon oxide meet. The voids and tunnels reconfigure into a single tunnel as the growth proceeds.Image: Rui-Tao WenMaterials Research Laboratory, Materials Science and Engineering, electronics, Photonics, Microfluidics, Semiconductors, DMSE, School of Engineering, Research Researchers discover a new way to control infrared light The new method could impact devices used in imaging, machine learning, and more. Thu, 30 Jan 2020 09:00:01 -0500 Anne McGovern | Lincoln Laboratory <p>In the 1950s, the field of electronics began to change when the transistor replaced vacuum tubes in computers. The change, which entailed replacing large and slow components with small and fast ones, was a catalyst for the enduring trend of miniaturization in computer design. No such revolution has yet hit the field of infrared optics, which remains reliant on bulky moving parts that preclude building small systems.</p> <p>However, a team of researchers at MIT Lincoln Laboratory, together with Professor <a href="">Juejun Hu</a> and graduate students from MIT's <a href="">Department of Materials Science and Engineering</a>, is devising a way to control infrared light by using phase-change materials instead of moving parts. These materials have the ability to change their optical properties when energy is added to them.</p> <p>“There are multiple possible ways where this material can enable new photonic devices that impact people’s lives,” says Hu. “For example, it can be useful for energy-efficient optical switches, which can improve network speed and reduce power consumption of internet data centers. It can enable reconfigurable meta-optical devices, such as compact, flat infrared zoom lenses without mechanical moving parts. It can also lead to new computing systems, which can make machine learning faster and more power-efficient compared to current solutions.”</p> <p>A fundamental property of phase-change materials is that they can change how fast light travels through them (the refractive index). “There are already ways to modulate light using a refractive index change, but phase-change materials can change almost 1,000 times better,” says Jeffrey Chou, a team member formerly in the laboratory's Advanced Materials and Microsystems Group.</p> <p>The team successfully controlled infrared light in multiple systems by using a new class of phase-change material containing the elements germanium, antimony, selenium, and tellurium, collectively known as GSST. This work is discussed in a <a href="" target="_blank">paper</a> published in <em>Nature Communications.</em></p> <p>A phase-change material's magic occurs in the chemical bonds that tie its atoms together. In one phase state, the material is crystalline, with its atoms arranged in an organized pattern. This state can be changed by applying a short, high-temperature spike of thermal energy to the material, causing the bonds in the crystal to break down and then reform in a more random, or amorphous, pattern. To change the material back to the crystalline state, a long- and medium-temperature pulse of thermal energy is applied.</p> <p>“This changing of the chemical bonds allows for different optical properties to emerge, similar to the differences between coal (amorphous) and diamond (crystalline),” says Christopher Roberts, another Lincoln Laboratory member of the research team. “While both materials are mostly carbon, they have vastly different optical properties.”</p> <p>Currently, phase-change materials are used for industry applications, such as Blu-ray technology and rewritable DVDs, because their properties are useful for storing and erasing a large amount of information. But so far, no one has used them in infrared optics because they tend to be transparent in one state and opaque in the other. (Think of the diamond, which light can pass through, and coal, which light cannot penetrate.) If light cannot pass through one of the states, then that light cannot be adequately controlled for a range of uses; instead, a system would only be able to work like an on/off switch, allowing light to either pass through the material or not pass through at all.</p> <p>However, the research team found that that by adding the element selenium to the original material (called GST), the material's absorption of infrared light in the crystalline phase decreased dramatically — in essence, changing it from an opaque coal-like material to a more transparent diamond-like one. What's more, the large difference in the refractive index of the two states affects the propagation of light through them.</p> <p>“This change in refractive index, without introducing optical loss, allows for the design of devices that control infrared light without the need for mechanical parts,” Roberts says.</p> <p>As an example, imagine a laser beam that is pointing in one direction and needs to be changed to another. In current systems, a large mechanical gimbal would physically move a lens to steer the beam to another position. A thin-film lens made of GSST would be able change positions by electrically reprogramming the phase-change materials, enabling beam steering with no moving parts.</p> <p>The team has already tested the material successfully in a moving lens. They have also demonstrated its use in infrared hyperspectral imaging, which is used to analyze images for hidden objects or information, and in a fast optical shutter that was able to close in nanoseconds.</p> <p>The potential uses for GSST are vast, and an ultimate goal for the team is to design reconfigurable optical chips, lenses, and filters, which currently must be rebuilt from scratch each time a change is required. Once the team is ready to move the material beyond the research phase, it should be fairly easy to transition it into the commercial space. Because it's already compatible with standard microelectronic fabrication processes, GSST components could be made at a low cost and in large numbers.</p> <p>Recently, the laboratory obtained a combinatorial sputtering chamber — a state-of-the-art machine that allows researchers to create custom materials out of individual elements. The team will use this chamber to further optimize the materials for improved reliability and switching speeds, as well as for low-power applications. They also plan to experiment with other materials that may prove useful in controlling visible light.</p> <p>The next steps for the team are to look closely into real-world applications of GSST and understand what those systems need in terms of power, size, switching speed, and optical contrast.</p> <p>“The impact [of this research] is twofold,” Hu says. "Phase-change materials offer a dramatically enhanced refractive index change compared to other physical effects — induced by electric field or temperature change, for instance — thereby enabling extremely compact reprogrammable optical devices and circuits. Our demonstration of bistate optical transparency in these materials is also significant in that we can now create high-performance infrared components with minimal optical loss.” The new material, Hu continues, is expected to open up an entirely new design space in the field of infrared optics.</p> <p>This research was supported with funding from the laboratory's <a href="">Technology Office</a> and the U.S. <a href="">Defense Advanced Research Projects Agency</a>.</p> This 8-inch wafer contains phase-change pixels that can be controlled to modulate light. Researchers are studying the properties and behaviors of the pixels to inform the creation of future devices that use phase-change materials.Image: Nicole FandelLincoln Laboratory, Materials Science and Engineering, Photonics, Research, Imaging, DMSE, School of Engineering, Defense Advanced Research Projects Agency (DARPA) Accelerating the pace of engineering The 2019-20 School of Engineering MathWorks Fellows are using MATLAB and Simulink to advance discovery and innovation across disciplines. Tue, 28 Jan 2020 17:00:01 -0500 Lori LoTurco | School of Engineering <p>Founded in 1984 by Jack Little ’78 and Cleve Moler, MathWorks was built on the premise of providing engineers and scientists with more powerful and productive computation environments. In 1985, the company sold its very first order&nbsp;— 10 copies of its first product, MATLAB — to MIT.</p> <p>Decades later, engineers across MIT and around the world consistently rely on MathWorks products to accelerate the pace of discovery, innovation, and development in automotive, aerospace, electronics, biotech-pharmaceutical, and other industries.&nbsp;MathWorks’ products and support have had a significant impact on <em>MITx,</em> OpenCourseWare, and MIT’s digital learning efforts across campus, including the Department of Mathematics, one of the School of Engineering’s closest collaborators in the use of digital learning tools and educational technologies.</p> <p>“We have a strong belief in the importance of engineers and scientists,” says Little. “They act to increase human knowledge and profoundly improve our standard of living. We create products like MATLAB and Simulink to help them do their best work.”</p> <p>As the language of technical computing, MATLAB is a programming environment for algorithm development, data analysis, visualization, and numeric computation. It is used extensively by faculty, students, and researchers across MIT and by over 4 million users in industry, government, and academia in 185 countries.</p> <p>Simulink is a block diagram environment for simulation and model-based design of multidomain and embedded engineering systems, including automatic code generation, verification, and validation. It is used heavily in automotive, aerospace, and other applications that design complex real-time systems.</p> <p>This past summer, MathWorks celebrated 35 years of accelerating the pace of engineering and science. Shortly following this milestone, MathWorks awarded 11 engineering fellowships to graduate students within the School of Engineering who are active users of MATLAB or Simulink. The fellows are using the programs to advance discovery and innovation across disciplines.</p> <p>“PhD fellowships are an investment in the world’s long-term future, and there are few investments more valuable than that,” says Little.</p> <p>The 2019-20 MathWorks fellows are:</p> <p><a href="">Pasquale Antonante</a> is a PhD student in the Department of Aeronautics and Astronautics. He uses MATLAB and Simulink to build tools that make robots more accurate.</p> <p><a href="">Alireza Fallah</a> is a PhD student in the Department of Electrical Engineering and Computer Science. He uses Matlab and Symbolic Math Toolbox to develop better machine-learning algorithms.</p> <p><a href="">James Gabbard</a> is a SM/PhD student in the Department of Mechanical Engineering. He uses MATLAB to model fluids and materials.</p> <p><a href="">Nicolas Meirhaeghe</a><strong> </strong>is a PhD student in medical engineering and medical physics in the Bioastronautics Training Program at Harvard-MIT Division of Health Sciences and Technology. He uses MATLAB to visualize activity in the brain and understand how it is related to an individual’s behavior.</p> <p><a href="">Caroline Nielsen</a> is a PhD student in the Department of Chemical Engineering. She uses MATLAB to implement and test new applications of non-smooth analysis. She also intends to use MATLAB to in the next phase of her research, developing methods to simultaneously optimize for minimal resource use and operating costs.</p> <p><a href="">Bauyrzhan Primkulov</a><strong> </strong>is a PhD student in the Department of Civil and Environmental Engineering. He uses MATLAB to build computational models and explore how fluids interact in porous materials.</p> <p><a href="">Kate Reidy</a><strong> </strong>is a PhD student in the Department of Materials Science and Engineering. She studies how 2D materials — only a single atom thick — can be combined with 3D materials, and uses MATLAB to analyze the properties of different materials.</p> <p><a href="">Isabelle Su</a><strong> </strong>is a PhD student in civil and environmental engineering. She builds computational models with MATLAB to understand the mechanical properties of spider webs.</p> <p><a href="">Joy Zeng</a><strong> </strong>is a PhD student in chemical engineering. Her research is focused on the electrochemical transformation of carbon dioxide to fuels and commodity chemicals. She uses MATLAB to model chemical reactions.</p> <p><a href="">Benjamin "Jiahong" Zhang</a><strong> </strong>is a PhD student in computational science and engineering. He uses MATLAB to prototype new methods for rare event simulation, finding new methods by leveraging mathematical principles used in proofs and re-purposing them for computation.</p> <p><a href="">Paul Zhang</a><strong> </strong>is a PhD student in electrical engineering and computer science. He uses MATLAB to develop algorithms with applications in meshing — the use of simple shapes to study complex ones.</p> <p>For MathWorks, fostering engineering education is a priority, so when deciding where to focus philanthropic support, MIT — its very first customer — was an obvious choice.</p> <p>“We are so humbled by MathWorks' generosity, and their continued support of our engineering students through these fellowships,” says Anantha Chandrakasan, dean of the School of Engineering. “Our relationship with MathWorks is one that we revere — they have developed products that foster research and advancement across many disciplines, and through their support our students launch discoveries and innovation that align with MathWorks’ mission.”</p> MathWorks fellows with Anantha Chandrakasan (back row, center), dean of the MIT School of Engineering. Not pictured: Fellows Pasquale Antonante, Alireza Fallah, and Kate Reidy.Photo: David DegnerSchool of Engineering, MITx, OpenCourseWare, Mathematics, Electrical engineering and computer science (EECS), Mechanical engineering, Chemical engineering, Civil and environmental engineering, Awards, honors and fellowships, Harvard-MIT Health Sciences and Technology, Alumni/ae, Startups, Aeronautical and astronautical engineering, DMSE, Computer science and technology, School of Science Communicating respect for graduate students Anna Frebel, Wesley Harris, and Harry Tuller honored by graduate students as “Committed to Caring.” Mon, 27 Jan 2020 09:00:00 -0500 Courtney Lesoon | Office of Graduate Education <p>Mitigating the stresses of graduate school requires dedicated community support and mentorship. Professors Wesley Harris, Anna Frebel, and Harry Tuller have been honored by graduate students as “Committed to Caring” for the manifold ways they demonstrate their respect for students.</p> <p><strong>Anna Frebel: listening and lifting up</strong></p> <p>Frebel says that “it is a gift to be able to tell, especially&nbsp;younger women, 'You can do it — I believe in you and your ideas.'”</p> <p>Frebel joined the MIT physics faculty in 2012 as assistant professor and was promoted to associate professor of physics with tenure in 2018. Frebel is best known for her discoveries, and subsequent analyses, of the oldest stars in the universe. Her research offers insight into how these stars can be used to understand the first billion years after the Big Bang, the beginning of star and galaxy formation, and the origin of the chemical elements.</p> <p>The career path of a woman in physics is bumpier than it should be. “I have seen too many cases where women have been left unprepared for what's to come because advisors were too busy or didn't care to share insight,” Frebel laments. To help address a lacuna in advising, Frebel developed a series of professional&nbsp;career development seminars to&nbsp;offer&nbsp;graduate women in MIT’s Department of Physics practical tools&nbsp;and insights on many unspoken topics and expectations in academia.</p> <p>It is paramount for a department to develop policies to set expectations for peer behavior and community values while also, in Frebel’s words,&nbsp;“broadcasting&nbsp;that poor behavior in the workplace is never welcome in the first place.” For example, the Department of Physics has developed a list of <a href="" target="_blank">Community Values</a>. Frebel’s advocating for students is a mentoring guidepost identified by the Committed to Caring (C2C) program.</p> <p>Frebel’s goal is to make time, demonstrate respect for her students, and to treat them as junior colleagues.&nbsp;Such behaviors, she says, “govern healthy relationships” between faculty and students. One student remarks that Frebel's “compassion and commitment to caring” have made the department a friendlier, stronger, and more inclusive place.</p> <p><strong>Wesley Harris: transcending boundaries</strong></p> <p>Professor Wesley Harris looks out for his students whether their struggles are research-related or personal. “Anytime I come across [Harris] in the hallway,” one student nominator writes, “I know I can always speak my mind and … get some insightful guidance and unwavering support.”</p> <p>Wesley L. Harris is the C.S. Draper Professor of Aeronautics and Astronautics at MIT. Harris joined the MIT faculty in 1972. He has since served as associate administrator for aeronautics at NASA, as vice president of the University of Tennessee Space Institute, and as dean of the School of Engineering at the University of Connecticut. Harris’ research foci include fluid dynamics, unsteady aerodynamics, and aeroacoustics. His research extends beyond the field of aeronautics and astronautics to include the microcirculation and hemodynamics of sickle cell disease, as well as studies of lean financial management methods and the sustainment of capital assets.</p> <p>In spring 2015, after MIT had witnessed several suicides on campus, Harris dedicated an entire lecture of his Analytical High Speed Aerodynamics course to talk about suicide with his students. Having such courageous conversations with students is a mentoring guidepost identified by the C2C program.</p> <p>“I was truly touched by his effort to communicate, and I could tell he really cared,” one student remembers. “I had never seen a faculty member try this hard to bridge the divide [between faculty and students] until then, and I have not seen another faculty member try and do the same since.”</p> <p>The relationship between a faculty mentor and their graduate student is one that requires mutual respect and trust. Harris notes that, especially initially, “the power balance favors the faculty member in the partnership. Hence, it is incumbent upon me to reach out to my students.”</p> <p>Students in the Harris lab regularly present research updates to their lab mates. In these meetings, Harris and each attending student offer the presenter both critical and encouraging feedback. Harris affirms, “Our community is never a no-praise zone.”</p> <p><strong>Harry Tuller: encouraging and energizing</strong></p> <p>Keeping each of his students’ needs in mind, Professor Harry Tuller’s mentorship style is personalized and enthusiastic. As one student notes, he is “an amazingly kind and curious man, who is willing to help anyone who shows up and tries.”</p> <p>Harry Tuller is the R.P. Simmons Professor of Ceramics and Electronic Materials in the Department of Materials Science and Engineering and director of the Crystal Physics and Electroceramics Laboratory at MIT. Currently, his research emphasizes modeling, processing, characterizing, and optimizing energy-related devices such as sensors, batteries, fuel cells, and solar/photolysis cells, as well as integrating sensor, actuator, and photonic materials into microelectromechanical systems. His research has been extensively published in over 485 articles, 15 co-edited books, and 33 patents.</p> <p>When Tuller notices that a student is losing enthusiasm for their work, he reaches out to set up a meeting. Proactive outreach is a mentoring guidepost identified by the C2C program. One of his students had to take a break from school owing to anxiety and depression, and Tuller provided the necessary support for the student to get help. He later aided the student’s successful transition back into work.“[Tuller] met with me on multiple occasions,” the student said, “to help me parse through my own anxieties and concerns with anecdotes from himself and his past students.”</p> <p>Every student responds to challenges and rewards differently, Tuller says, so it is important to provide advising suited to the individual. Learning what types of stressors affect each student can go a long way in alleviating anxiety-provoking situations for students and in helping students manage their own stress.</p> <p>In order to keep moving forward, Tuller urges students to “communicate their research goals clearly and convincingly and to be open to constructive criticism.” Tuller’s consistent contact and tailored support has contributed to his students’ resounding success.</p> <p><strong>More on Committed to Caring</strong></p> <p>The Committed to Caring program is an initiative of the Office of Graduate Education and contributes to its mission of making graduate education at MIT “empowering, exciting, holistic, and transformative.”</p> <p>C2C invites graduate students from across MIT’s campus to nominate professors whom they believe to be outstanding mentors. Selection criteria for the honor include the scope and reach of advisor impact on graduate students’ experience, excellence in scholarship, and demonstrated commitment to diversity and inclusion.</p> <p>By recognizing the human element of graduate education, C2C seeks to encourage excellent advising and mentorship across MIT’s campus. More information about these and other C2C honorees and their advising practices may be found on the Committed to Caring pages.</p> Left to right: Anna Frebel, Wesley Harris, and Harry Tuller are recognized as MIT faculty “Committed to Caring.”Photos: Joseph LeePhysics, Aeronautics and Astronautics, Materials Science and Engineering, Mentoring, Awards, honors and fellowships, Leadership, Faculty, Community, Graduate, postdoctoral, Women in STEM, DMSE, School of Science, School of Engineering For cheaper solar cells, thinner really is better Solar panel costs have dropped lately, but slimming down silicon wafers could lead to even lower costs and faster industry expansion. Sun, 26 Jan 2020 23:59:59 -0500 David L. Chandler | MIT News Office <p>Costs of solar panels have plummeted over the last several years, leading to rates of solar installations far greater than most analysts had expected. But with most of the potential areas for cost savings already pushed to the extreme, further cost reductions are becoming more challenging to find.</p> <p>Now, researchers at MIT and at the National Renewable Energy Laboratory (NREL) have outlined a pathway to slashing costs further, this time by slimming down the silicon cells themselves.</p> <p>Thinner silicon cells have been explored before, especially around a dozen years ago when the cost of silicon peaked because of supply shortages. But this approach suffered from some difficulties: The thin silicon wafers were too brittle and fragile, leading to unacceptable levels of losses during the manufacturing process, and they had lower efficiency. The researchers say there are now ways to begin addressing these challenges through the use of better handling equipment and some recent developments in solar cell architecture.</p> <p>The new findings are detailed in a paper in the journal <em>Energy and Environmental Science</em>, co-authored by MIT postdoc Zhe Liu, professor of mechanical engineering Tonio Buonassisi, and five others at MIT and NREL.</p> <p>The researchers describe their approach as “technoeconomic,” stressing that at this point economic considerations are as crucial as the technological ones in achieving further improvements in affordability of solar panels.</p> <p>Currently, 90 percent of the world’s solar panels are made from crystalline silicon, and the industry continues to grow at a rate of about 30 percent per year, the researchers say. Today’s silicon photovoltaic cells, the heart of these solar panels, are made from wafers of silicon that are 160 micrometers thick, but with improved handling methods, the researchers propose this could be shaved down to 100 micrometers —&nbsp; and eventually as little as 40 micrometers or less, which would only require one-fourth as much silicon for a given size of panel.</p> <p>That could not only reduce the cost of the individual panels, they say, but even more importantly it could allow for rapid expansion of solar panel manufacturing capacity. That’s because the expansion can be constrained by limits on how fast new plants can be built to produce the silicon crystal ingots that are then sliced like salami to make the wafers. These plants, which are generally separate from the solar cell manufacturing plants themselves, tend to be capital-intensive and time-consuming to build, which could lead to a bottleneck in the rate of expansion of solar panel production. Reducing wafer thickness could potentially alleviate that problem, the researchers say.</p> <p>The study looked at the efficiency levels of four variations of solar cell architecture, including PERC (passivated emitter and rear contact) cells and other advanced high-efficiency technologies, comparing their outputs at different thickness levels. The team found there was in fact little decline in performance down to thicknesses as low as 40 micrometers, using today’s improved manufacturing processes.</p> <p>“We see that there’s this area (of the graphs of efficiency versus thickness) where the efficiency is flat,” Liu says, “and so that’s the region where you could potentially save some money.” Because of these advances in cell architecture, he says, “we really started to see that it was time to revisit the cost benefits.”</p> <p>Changing over the huge panel-manufacturing plants to adapt to the thinner wafers will be a time-consuming and expensive process, but the analysis shows the benefits can far outweigh the costs, Liu says. It will take time to develop the necessary equipment and procedures to allow for the thinner material, but with existing technology, he says, “it should be relatively simple to go down to 100 micrometers,” which would already provide some significant savings. Further improvements in technology such as better detection of microcracks before they grow could help reduce thicknesses further.</p> <p>In the future, the thickness could potentially be reduced to as little as 15 micrometers, he says. New technologies that grow thin wafers of silicon crystal directly rather than slicing them from a larger cylinder could help enable such further thinning, he says.</p> <p>Development of thin silicon has received little attention in recent years because the price of silicon has declined from its earlier peak. But, because of cost reductions that have already taken place in solar cell efficiency and other parts of the solar panel manufacturing process and supply chain, the cost of the silicon is once again a factor that can make a difference, he says.</p> <p>“Efficiency can only go up by a few percent. So if you want to get further improvements, thickness is the way to go,” Buonassisi says. But the conversion will require large capital investments for full-scale deployment.</p> <p>The purpose of this study, he says, is to provide a roadmap for those who may be planning expansion in solar manufacturing technologies. By making the path “concrete and tangible,” he says, it may help companies incorporate this in their planning. “There is a path,” he says. “It’s not easy, but there is a path. And for the first movers, the advantage is significant.”</p> <p>What may be required, he says, is for the different key players in the industry to get together and lay out a specific set of steps forward and agreed-upon standards, as the integrated circuit industry did early on to enable the explosive growth of that industry. “That would be truly transformative,” he says.</p> <p>Andre Augusto, an associate research scientist at Arizona State University who was not connected with this research, says “refining silicon and wafer manufacturing is the most capital-expense (capex) demanding part of the process of manufacturing solar panels. So in a scenario of fast expansion, the wafer supply can become an issue. Going thin solves this problem in part as you can manufacture more wafers per machine without increasing significantly the capex.” He adds that “thinner wafers may deliver performance advantages in certain climates,” performing better in warmer conditions.</p> <p>Renewable energy analyst Gregory Wilson of Gregory Wilson Consulting, who was not associated with this work, says “The impact of reducing the amount of silicon used in mainstream cells would be very significant, as the paper points out. The most obvious gain is in the total amount of capital required to scale the PV industry to the multi-terawatt scale required by the climate change problem. Another benefit is in the amount of energy required to produce silicon PV panels. This is because the polysilicon production and ingot growth processes that are required for the production of high efficiency cells are very energy intensive.”</p> <p>Wilson adds “Major PV cell and module manufacturers need to hear from credible groups like Prof. Buonassisi’s at MIT, since they will make this shift when they can clearly see the economic benefits.”</p> <p>The team also included Sarah Sofia, Hannu Lane, Sarah Wieghold and Marius Peters at MIT and Michael Woodhouse at NREL. The work was partly supported by the U.S. Department of Energy, the Singapore-MIT Alliance for Research and Technology (SMART),&nbsp;and by a Total Energy Fellowship through the MIT Energy Initiative.</p> Currently, 90 percent of the world’s solar panels are made from crystalline silicon, and the industry continues to grow at a rate of about 30 percent per year.Research, School of Engineering, Energy, Solar, Nanoscience and nanotechnology, Materials Science and Engineering, Mechanical engineering, Renewable energy, Alternative energy, Sustainability, MIT Energy Initiative, Climate change, Department of Energy (DoE), Singapore-MIT Alliance for Research and Technology (SMART) MIT graduate students lead conference on microsystems and nanotechnology Student committee puts together research showcase while balancing coursework, qualifying exams, and extracurriculars. Wed, 22 Jan 2020 12:30:01 -0500 Amanda Stoll | MIT.nano <p>Organizing the Microsystems Annual Research Conference (<a href="">MARC</a>) is no small feat. Each January during the MIT Independent Activities Period, more than 200 students, faculty, staff, postdocs, and industry members come together at an off-campus site to explore technical achievements and research ideas at the forefront of microsystems and nanotechnology.</p> <p>The secret to MARC’s success year after year? A student committee that handles every aspect of coordinating and executing the showcase event, to be held this year in late January in New Hampshire. Chaired by MIT doctoral students Mayuran Saravanapavanantham and Rachel Yang, the 2020 student leaders arrange for research talks, poster presentations, keynote lectures, and all of the logistics for transporting scores of attendees to and from the conference.</p> <p>Part research symposium and part networking event, MARC strives to share new research directions, identify job opportunities, and help participants refine their technical communications skills — with a bit of skiing and snowshoeing on the side.</p> <p>“MARC has many moving parts that have to be managed simultaneously,” says Saravanapavanantham, a third-year graduate student in Professor Vladimir Bulović’s Organic and Nanostructured Electronics (ONE) Lab. “In planning a large, off-campus conference, it’s really important to have a strong, dedicated committee. MARC caters to a broad audience, so we have to make sure we tie everything together to keep everyone engaged.”</p> <p>Saravanapavanantham and Yang have each participated in two previous MARC conferences. Together, they have been overseeing a student committee of 13 individuals over the past six months to recreate positive elements of previous MARCs and generate new solutions to old challenges.</p> <p><strong>A strong foundation</strong></p> <p>Now in its 16th year, the conference has expanded significantly since its inception. It grew out of the semesterly VLSI Research Reviews, which began in 1984 under the Microsystems Research Center. From there, it evolved into a faculty-run research review that became known as the Microsystems Technology Laboratories (MTL) Annual Student Review. In 2005, the event was rebranded as MARC and became the student-run conference that exists today. This year, the conference is co-sponsored for the first time by MTL and MIT.nano.</p> <p>The organizing committee comprises eight core committee members and five session chairs. The core committee takes on logistical responsibilities such as finding speakers, building the agenda, and working with vendors, while the session chairs focus on abstract submissions from over 90 MIT student presenters.</p> <p>To keep on track, the team follows a strict timeline passed down from previous MARC co-chairs. The committee must monitor not only registration deadlines, but hotel reservations, transportation, printing of materials, and abstract reviews.</p> <p>This year, the responsibilities are broken into eight categories, each chaired by a different PhD student: Navid Abedzadeh of the Department of Electrical Engineering and Computer Scence (EECS) is managing photography; Jessica Boles of EECS is managing communications training; Elaine McVay of EECS is managing social activities; Rishabh Mittal of EECS is managing registration logistics; Jatin Patil of the Department of Materials Science and Engineering is managing the website and proceedings; Morteza Sarmadi of the Department of Mechanical Engineering (MechE) is managing outreach; Jay Sircar of MechE is managing winter activities and transportation; and Miaorong Wang of EECS is managing audio/visual presentations.</p> <p><strong>Appealing to a wide audience</strong></p> <p>“One of the greatest challenges of MARC is promoting the event to encourage students, faculty, staff, and industry members to attend,” explains Yang, a second-year graduate student working on power magnetics design in Professor David Perreault’s power electronics group. “This year, we dedicated more efforts to our marketing, including adding an outreach chair to our committee.”</p> <p>Their efforts paid off with 20 faculty and PIs registered to attend, a significant increase from previous years. The MARC committee also decided to make poster pitches optional in 2020 to increase students’ interest in participating.</p> <p>Each year, MARC aims to host 100 poster presenters from nearly 40 research groups across seven categories. Participating students are required to go through at least one round of abstract feedback and edits, maintaining MARC’s reputation of high-quality writing. “Communications training is an essential part of the conference. We train students in abstract writing, poster design, and pitch preparation,” says Saravanapavanantham. “This helps MARC participants prepare to submit their work at future conferences.”</p> <p>Abstracts are divided into eight categories that are reviewed by the 2020 session chairs. Topics include electronic and quantum devices, energy harvesting, medical devices, biotechnology, and photonics, to name a few. The five MIT students reviewing this year’s abstract submissions, all current EECS PhD students, are Mohamed Ibrahim, Kruthika Kikkeri, Jane Lai, Haozhe Wang and Qingyun Xie.</p> <p>The student committee is also charged with identifying and securing keynote speakers who are experts in their field. The 2020 keynote lectures will focus on driving innovation at all scales. The speakers include Reed Sturtevant, who, as general partner of The Engine, a venture capital firm built by MIT, facilitates the launch of new technologies through startup incubation; and Mark Rosker, director of the U.S. Defense Advanced Research Projects Agency’s Microsystems Technology Office, which sets direction for micro/nanoelectronics research at a national level.</p> <p>Saravanapavanantham and Yang are excited to see the committee’s planning efforts come to life at MARC 2020. The two are also looking toward the future, documenting their processes and reflecting on their visions for the future: “We hope this conference will continue to grow as a platform to inspire ideas and to foster research collaboration between MIT and industry,” said Yang.</p> Left to right: MARC committee members and MIT graduate students Navid Abedzadeh, Mayuran Saravanapavanantham, Haozhe Wang, Elaine McVay, Qingyun Xie, Jatin Patil, Jessica Boles, Rachel Yang, and Rishabh Mittal. Photo: Navid AbedzadehMicrosystems Technology Laboratories, MIT.nano, Special events and guest speakers, Mechanical engineering, Graduate, postdoctoral, DMSE, Industry, electronics, Independent Activities Period, Students, Nanoscience and nanotechnology, School of Engineering Pablo Jarillo-Herrero wins Wolf Prize for groundbreaking work on twistronics Professor of physics honored alongside Allan MacDonald and Rafi Bistritzer for pioneering research on twisted bilayer graphene. Thu, 16 Jan 2020 13:30:01 -0500 Carol Breen | Department of Physics <p>Cecil and Ida Green Professor of Physics Pablo Jarillo-Herrero was awarded the 2020 Wolf Prize in Physics&nbsp;for his experimental contributions to breakthrough developments in twisted bilayer graphene research, which uncovered unique electrical properties with the long-range potential for creating new superconducting materials.</p> <p>The condensed-matter experimentalist shares the prize with theorists Professor Allan MacDonald of the University of Texas at Austin, and Rafi Bistrizter of Applied Materials Israel.&nbsp;</p> <p>"It's an incredible and humbling honor to receive this recognition," says Jarillo-Herrero. "I see it as an acknowledgement, and appreciation, by the global physics community for the work of my fantastic group of graduate students and postdocs, as well as my collaborators here at MIT and around the world." He adds, "I hope this prize will motivate young physicists to pursue the beautiful field of 2D materials!"</p> <p>Professor Peter Fisher, head of the Department of Physics, notes, “The twisted graphene result is in a class of its own, and we are very excited about it. Pablo is a real leader at MIT and this work adds to his already great stature."</p> <p>Thanks to game-changing discoveries 15 years ago relating to the electronic properties of two-dimensional graphene — the world’s best electrical conductor — physics and materials science researchers have since developed a new field, dubbed&nbsp;“twistronics.”</p> <p>Twistronics researchers study how it is possible to "tune" the electronic properties of two-dimensional materials by changing, or "twisting," the angle of rotation between two adjacent crystalline layers of graphene. Such tuning through twisting is unprecedented in the history of quantum materials.&nbsp;</p> <p>In Jarillo-Herrero’s group, experiments were inspired by a <a href="" target="_blank">2011 paper</a> by theorists MacDonald and Bistritzer predicting the interesting properties of electrons resulting from the rotating, or twisting,&nbsp;of the atomic lattices of stacked layers of graphene.&nbsp;</p> <p>By creating and measuring bilayer graphene of multiple twist angles, Jarillo-Herrero's group reached a breakthrough in 2018 with the discovery of “<a href="" target="_blank">the magic angle</a>” — two layers positioned at 1.1 degrees — that resulted in unique, entirely unpredicted electronic behaviors.&nbsp;</p> <p>At this "magic angle," and at low temperatures, electrons in twisted bilayer graphene were seen to slow down tremendously, as predicted years earlier. However, the electron slowdown discovered by Jarillo-Herrero and collaborators also led to new, fascinating behaviors, such as novel insulating and superconducting states.&nbsp;</p> <p>The new field of twistronics, with the experimental and theoretical challenges of observing and tuning these new electronic behaviors into a single material platform, has become a next-generation game-changer and brings together multiple branches of condensed-matter physics.&nbsp;&nbsp;</p> <p>While most current research efforts are still focused on understanding the fundamental physics of these new “twisted” materials, the insights provided are expected to have a major impact in multiple areas of science and technology — ranging from the design of new superconductors operating at higher temperatures to the development of novel quantum devices for advanced quantum sensing, photonics, and computing applications.&nbsp;</p> <p>A native of Valencia, Spain, Jarillo-Herrero joined MIT as an assistant professor of&nbsp;physics in January 2008 and was promoted to full professor in 2018. His awards include an&nbsp;Alfred P. Sloan Fellowship; a David and Lucile Packard Fellowship; a DOE Early Career&nbsp;Award; a Presidential Early Career Award for Scientists and Engineers; an ONR Young Investigator Award; a Moore Foundation Experimental Physics in Quantum&nbsp;Systems Investigator Award; and the Oliver E. Buckley Condensed Matter Physics&nbsp;Prize. In 2018, Jarillo-Herrero was elected a Fellow of the American Physical Society.</p> <p>The annual international prize of the Israeli-based Wolf Foundation, the Wolf Prize is now in its 42nd year, and celebrates exceptional achievement worldwide in the sciences and arts done "in the interest of mankind and friendly relations among peoples." Awards are given broadly, in fields ranging from physics, chemistry, mathematics, and agriculture to painting and sculpture, music, and architecture.&nbsp;</p> <p>Prior Wolf Prize laureates in the MIT Department of Physics include Lester Wolfe Professor of&nbsp;Physics Emeritus Daniel Kleppner (2005) and MIT Institute Professors Emeriti Bruno Rossi&nbsp;(1987) and Victor Weisskopf (1981).</p> A native of Valencia, Spain, Pablo Jarillo-Herrero joined MIT as an assistant professor of physics in January 2008 and was promoted to full professor in 2018.Photo: BBVA FoundationPhysics, Graphene, Superconductors, School of Science, Awards, honors and fellowships, Faculty, Carbon, Materials Science and Engineering, Quantum physics A new approach to making airplane parts, minus the massive infrastructure Carbon nanotube film produces aerospace-grade composites with no need for huge ovens or autoclaves. Mon, 13 Jan 2020 00:00:00 -0500 Jennifer Chu | MIT News Office <p>A modern airplane’s fuselage is made from multiple sheets of different composite materials, like so many layers in a phyllo-dough pastry. Once these layers are stacked and molded into the shape of a fuselage, the structures are wheeled into warehouse-sized ovens and autoclaves, where the layers fuse together to form a resilient, aerodynamic shell.</p> <p>Now MIT engineers have developed a method to produce aerospace-grade composites without the enormous ovens and pressure vessels. The technique may help to speed up the manufacturing of airplanes and other large, high-performance composite structures, such as blades for wind turbines.</p> <p>The researchers detail their new method in a paper published today in the journal <em>Advanced Materials Interfaces. </em></p> <p>“If you’re making a primary structure like a fuselage or wing, you need to build a pressure vessel, or autoclave, the size of a two- or three-story building, which itself requires time and money to pressurize,” says Brian Wardle, professor of aeronautics and astronautics at MIT. “These things are massive pieces of infrastructure. Now we can make primary structure materials without autoclave pressure, so we can get rid of all that infrastructure.”</p> <p>Wardle’s co-authors on the paper are lead author and MIT postdoc Jeonyoon Lee, and Seth Kessler of Metis Design Corporation, an aerospace structural health monitoring company based in Boston.</p> <p><strong>Out of the oven, into a blanket</strong></p> <p>In 2015, Lee led the team, along with another member of Wardle’s lab, in creating a method to make aerospace-grade composites without requiring an oven to fuse the materials together. Instead of placing layers of material inside an oven to cure, the researchers essentially wrapped them in an ultrathin film of carbon nanotubes (CNTs). When they applied an electric current to the film, the CNTs, like a nanoscale electric blanket, quickly generated heat, causing the materials within to cure and fuse together.</p> <p>With this out-of-oven, or OoO, technique, the team was able to produce composites as strong as the materials made in conventional airplane manufacturing ovens, using only 1 percent of the energy.</p> <p>The researchers next looked for ways to make high-performance composites without the use of large, high-pressure autoclaves — building-sized vessels that generate high enough pressures to press materials together, squeezing out any voids, or air pockets, at their interface.</p> <p>“There’s microscopic surface roughness on each ply of a material, and when you put two plys together, air gets trapped between the rough areas, which is the primary source of voids and weakness in a composite,” Wardle says. “An autoclave can push those voids to the edges and get rid of them.”</p> <p>Researchers including Wardle’s group have explored “out-of-autoclave,” or OoA, techniques to manufacture composites without using the huge machines. But most of these techniques have produced composites where nearly 1 percent of the material contains voids, which can compromise a material’s strength and lifetime. In comparison, aerospace-grade composites made in autoclaves are of such high quality that any voids they contain are neglible and not easily measured.</p> <p>“The problem with these OoA approaches is also that the materials have been specially formulated, and none are qualified for primary structures such as wings and fuselages,” Wardle says. “They’re making some inroads in secondary structures, such as flaps and doors, but they still get voids.”</p> <p><strong>Straw pressure</strong></p> <p>Part of Wardle’s work focuses on developing nanoporous networks — ultrathin films made from aligned, microscopic material such as carbon nanotubes, that can be engineered with exceptional properties, including color, strength, and electrical capacity. The researchers wondered whether these nanoporous films could be used in place of giant autoclaves to squeeze out voids between two material layers, as unlikely as that may seem.</p> <p>A thin film of carbon nanotubes is somewhat like a dense forest of trees, and the spaces between the trees can function like thin nanoscale tubes, or capillaries. A capillary such as a straw can generate pressure based on its geometry and its surface energy, or the material’s ability to attract liquids or other materials.&nbsp;</p> <p>The researchers proposed that if a thin film of carbon nanotubes were sandwiched between two materials, then, as the materials were heated and softened, the capillaries between the carbon nanotubes should have a surface energy and geometry such that they would draw the materials in toward each other, rather than leaving a void between them. Lee calculated that the capillary pressure should be larger than the pressure applied by the autoclaves.</p> <p>The researchers tested their idea in the lab by growing films of vertically aligned carbon nanotubes using a technique they previously developed, then laying the films between layers of materials that are typically used in the autoclave-based manufacturing of primary aircraft structures. They wrapped the layers in a second film of carbon nanotubes, which they applied an electric current to to heat it up. They observed that as the materials heated and softened in response, they were pulled into the capillaries of the intermediate CNT film.</p> <p>The resulting composite lacked voids, similar to aerospace-grade composites that are produced in an autoclave. The researchers subjected the composites to strength tests, attempting to push the layers apart, the idea being that voids, if present, would allow the layers to separate more easily.</p> <p>“In these tests, we found that our out-of-autoclave composite was just as strong as the gold-standard autoclave process composite used for primary aerospace structures,” Wardle says.</p> <p>The team will next look for ways to scale up the pressure-generating CNT film. In their experiments, they worked with samples measuring several centimeters wide — large enough to demonstrate that nanoporous networks can pressurize materials and prevent voids from forming. To make this process viable for manufacturing entire wings and fuselages, researchers will have to find ways to manufacture CNT and other nanoporous films at a much larger scale.</p> <p>“There are ways to make really large blankets of this stuff, and there’s continuous production of sheets, yarns, and rolls of material that can be incorporated in the process,” Wardle says.</p> <p>He plans also to explore different formulations of nanoporous films, engineering capillaries of varying surface energies and geometries, to be able to pressurize and bond other high-performance materials.</p> <p>“Now we have this new material solution that can provide on-demand pressure where you need it,” Wardle says. “Beyond airplanes, most of the composite production in the world is composite pipes, for water, gas, oil, all the things that go in and out of our lives. This could make making all those things, without the oven and autoclave infrastructure.”</p> <p>This research was supported, in part, by Airbus, ANSYS, Embraer, Lockheed Martin, Saab AB, Saertex, and Teijin Carbon America through MIT’s Nano-Engineered Composite aerospace Structures (NECST) Consortium.</p> MIT postdoc Jeonyoon LeeImage: Melanie Gonick, MITAeronautical and astronautical engineering, Carbon nanotubes, Manufacturing, Materials Science and Engineering, Research, School of Engineering, Nanoscience and nanotechnology Julia Ortony: Concocting nanomaterials for energy and environmental applications The MIT assistant professor is entranced by the beauty she finds pursuing chemistry. Thu, 09 Jan 2020 14:00:01 -0500 Leda Zimmerman | MIT Energy Initiative <p>A molecular engineer,&nbsp;<a href="">Julia Ortony</a>&nbsp;performs a contemporary version of alchemy.</p> <p>“I take powder made up of disorganized, tiny molecules, and after mixing it up with water, the material in the solution zips itself up into threads 5 nanometers thick — about 100 times smaller than the wavelength of visible light,” says Ortony, the Finmeccanica Career Development Assistant Professor of Engineering in the Department of Materials Science and Engineering (DMSE). “Every time we make one of these nanofibers, I am amazed to see it.”</p> <p>But for Ortony, the fascination doesn’t simply concern the way these novel structures self-assemble, a product of the interaction between a powder’s molecular geometry and water. She is plumbing the potential of these nanomaterials for use in renewable energy and environmental remediation technologies, including promising new approaches to water purification and the photocatalytic production of fuel.</p> <p><strong>Tuning molecular properties</strong></p> <p>Ortony’s current research agenda emerged from a decade of work into the behavior of a class of carbon-based molecular materials that can range from liquid to solid.</p> <p>During doctoral work at the University of California at Santa Barbara, she used magnetic resonance (MR) spectroscopy to make spatially precise measurements of atomic movement within molecules, and of the interactions between molecules. At Northwestern University, where she was a postdoc, Ortony focused this tool on self-assembling nanomaterials that were biologically based, in research aimed at potential biomedical applications such as cell scaffolding and regenerative medicine.</p> <p>“With MR spectroscopy, I investigated how atoms move and jiggle within an assembled nanostructure,” she says. Her research revealed that the surface of the nanofiber acted like a viscous liquid, but as one probed further inward, it behaved like a solid. Through molecular design, it became possible to tune the speed at which molecules that make up a nanofiber move.</p> <p>A door had opened for Ortony. “We can now use state-of-matter as a knob to tune nanofiber properties,” she says. “For the first time, we can design self-assembling nanostructures, using slow or fast internal molecular dynamics to determine their key behaviors.”</p> <p><strong>Slowing down the dance</strong></p> <p>When she arrived at MIT in 2015, Ortony was determined to tame and train molecules for nonbiological applications of self-assembling “soft” materials.</p> <p>“Self-assembling molecules tend to be very dynamic, where they dance around each other, jiggling all the time and coming and going from their assembly,” she explains. “But we noticed that when molecules stick strongly to each other, their dynamics get slow, and their behavior is quite tunable.” The challenge, though, was to synthesize nanostructures in nonbiological molecules that could achieve these strong interactions.</p> <p>“My hypothesis coming to MIT was that if we could tune the dynamics of small molecules in water and really slow them down, we should be able to make self-assembled nanofibers that behave like a solid and are viable outside of water,” says Ortony.</p> <p>Her efforts to understand and control such materials are now starting to pay off.</p> <p>“We’ve developed unique, molecular nanostructures that self-assemble, are stable in both water and air, and — since they’re so tiny — have extremely high surface areas,” she says. Since the nanostructure surface is where chemical interactions with other substances take place, Ortony has leapt to exploit this feature of her creations — focusing in particular on their potential in environmental and energy applications.</p> <p><strong>Clean water and fuel from sunlight</strong></p> <p>One key venture, supported by Ortony’s Professor Amar G. Bose Fellowship, involves water purification. The problem of toxin-laden drinking water affects tens of millions of people in underdeveloped nations. Ortony’s research group is developing nanofibers that can grab deadly metals such as arsenic out of such water. The chemical groups she attaches to nanofibers are strong, stable in air, and in recent tests “remove all arsenic down to low, nearly undetectable levels,” says Ortony.</p> <p>She believes an inexpensive textile made from nanofibers would be a welcome alternative to the large, expensive filtration systems currently deployed in places like Bangladesh, where arsenic-tainted water poses dire threats to large populations.</p> <p>“Moving forward, we would like to chelate arsenic, lead, or any environmental contaminant from water using a solid textile fabric made from these fibers,” she says.</p> <p>In another research thrust, Ortony says, “My dream is to make chemical fuels from solar energy.” Her lab is designing nanostructures with molecules that act as antennas for sunlight. These structures, exposed to and energized by light, interact with a catalyst in water to reduce carbon dioxide to different gases that could be captured for use as fuel.</p> <p>In recent studies, the Ortony lab found that it is possible to design these catalytic nanostructure systems to be stable in water under ultraviolet irradiation for long periods of time. “We tuned our nanomaterial so that it did not break down, which is essential for a photocatalytic system,” says Ortony.</p> <p><strong>Students dive in</strong></p> <p>While Ortony’s technologies are still in the earliest stages, her approach to problems of energy and the environment are already drawing student enthusiasts.</p> <p>Dae-Yoon Kim, a postdoc in the Ortony lab, won the 2018 Glenn H. Brown Prize from the International Liquid Crystal Society for his work on synthesized photo-responsive materials and started a tenure track position at the Korea Institute of Science and Technology this fall. Ortony also mentors Ty Christoff-Tempesta, a DMSE doctoral candidate, who was recently awarded a Martin Fellowship for Sustainability. Christoff-Tempesta hopes to design nanoscale fibers that assemble and disassemble in water to create environmentally sustainable materials. And Cynthia Lo ’18 won a best-senior-thesis award for work with Ortony on nanostructures that interact with light and self-assemble in water, work that will soon be published. She is “my superstar&nbsp;<a href="">MIT Energy Initiative UROP</a>&nbsp;[undergraduate researcher],” says Ortony.</p> <p>Ortony hopes to share her sense of wonder about materials science not just with students in her group, but also with those in her classes. “When I was an undergraduate, I was blown away at the sheer ability to make a molecule and confirm its structure,” she says. With her new lab-based course for grad students — 3.65 (Soft Matter Characterization) — Ortony says she can teach about “all the interests that drive my research.”</p> <p>While she is passionate about using her discoveries to solve critical problems, she remains entranced by the beauty she finds pursuing chemistry. Fascinated by science starting in childhood, Ortony says she sought out every available class in chemistry, “learning everything from beginning to end, and discovering that I loved organic and physical chemistry, and molecules in general.”</p> <p>Today, she says, she finds joy working with her “creative, resourceful, and motivated” students. She celebrates with them “when experiments confirm hypotheses, and it’s a breakthrough and it’s thrilling,” and reassures them “when they come with a problem, and I can let them know it will be thrilling soon.”</p> <p><em>This article appears in the <a href="" target="_blank">Autumn 2019 issue of </a></em><a href="" target="_blank">Energy Futures</a>, <em>the magazine of the MIT Energy Initiative.</em></p> Julia Ortony is the Finmeccanica Career Development Assistant Professor of Engineering in the Department of Materials Science and Engineering.Photo: Lillie Paquette/School of EngineeringMIT Energy Initiative, Materials Science and Engineering, School of Engineering, Research, Faculty, DMSE, Chemistry, Nanoscience and nanotechnology, Renewable energy, Water Preventing energy loss in windows Mechanical engineers are developing technologies that could prevent heat from entering or escaping windows, potentially preventing a massive loss of energy. Mon, 06 Jan 2020 15:30:01 -0500 Mary Beth Gallagher | Department of Mechanical Engineering <p>In the quest to make buildings more energy efficient, windows present a particularly difficult problem. According to the U.S. Department of Energy, heat that either escapes or enters windows accounts for roughly 30 percent of the energy used to heat and cool buildings. Researchers are developing a variety of window technologies that could prevent this massive loss of energy.</p> <p>“The choice of windows in a building has a direct influence on energy consumption,” says Nicholas Fang, professor of mechanical engineering. “We need an effective way of blocking solar radiation.”</p> <p>Fang is part of a large collaboration that is working together to develop smart adaptive control and monitoring systems for buildings. The research team, which includes researchers from the Hong Kong University of Science and Technology and Leon Glicksman, professor of building technology and mechanical engineering at MIT, has been tasked with helping Hong Kong achieve its ambitious goal to reduce carbon emissions by 40 percent by 2025.</p> <p>“Our idea is to adapt new sensors and smart windows in an effort to help achieve energy efficiency and improve thermal comfort for people inside buildings,” Fang explains.</p> <p>His contribution is the development of a smart material that can be placed on a window as a film that blocks heat from entering. The film remains transparent when the surface temperature is under 32 degrees Celsius, but turns milky when it exceeds 32 C. This change in appearance is due to thermochromic microparticles that change phases in response to heat. The smart window’s milky appearance can block up to 70 percent of solar radiation from passing through the window, translating to a 30 percent reduction in cooling load.&nbsp;</p> <p>In addition to this thermochromic material, Fang’s team is hoping to embed windows with sensors that monitor sunlight, luminance, and temperature. “Overall, we want an integral solution to reduce the load on HVAC systems,” he explains.</p> <p>Like Fang, graduate student Elise Strobach is working on a material that could significantly reduce the amount of heat that either escapes or enters through windows. She has developed a high-clarity silica aerogel that, when placed between two panes of glass, is 50 percent more insulating than traditional windows and lasts up to a decade longer.</p> <p>“Over the course of the past two years, we’ve developed a material that has demonstrated performance and is promising enough to start commercializing,” says Strobach, who is a PhD candidate in MIT’s Device Research Laboratory. To help in this commercialization, Strobach has co-founded the startup <a href="">AeroShield Materials</a>.&nbsp;</p> <p>Lighter than a marshmallow, AeroShield’s material comprises 95 percent air. The rest of the material is made up of silica nanoparticles that are just 1-2 nanometers large. This structure blocks all three modes of heat loss: conduction, convection, and radiation. When gas is trapped inside the material’s small voids, it can no longer collide and transfer energy through convection. Meanwhile, the silica nanoparticles absorb radiation and re-emit it back in the direction it came from.</p> <p>“The material’s composition allows for a really intense temperature gradient that keeps the heat where you want it, whether it’s hot or cold outside,” explains Strobach, who, along with AeroShield co-founder Kyle Wilke, was named one of <a href="">Forbes’ 30 Under 30 in Energy</a>. Commercialization of this research is being supported by the MIT Deshpande Center for Technological Innovation.</p> <p>Strobach also sees possibilities for combining AeroShield technologies with other window solutions being developed at MIT, including Fang’s work and research being conducted by Gang Chen, Carl Richard Soderberg Professor of Power Engineering, and research scientist Svetlana Boriskina.</p> <p>“Buildings represent one third of U.S. energy usage, so in many ways windows are low-hanging fruit,” explains Chen.</p> <p>Chen and Boriskina previously worked with Strobach on the first iteration of the AeroShield material for their project developing a solar thermal aerogel receiver. More recently, they have developed polymers that could be used in windows or building facades to trap or reflect heat, regardless of color.&nbsp;</p> <p>These polymers were partially inspired by stained-glass windows. “I have an optical background, so I’m always drawn to the visual aspects of energy applications,” says Boriskina. “The problem is, when you introduce color it affects whatever energy strategy you are trying to pursue.”</p> <p>Using a mix of polyethylene and a solvent, Chen and Boriskina added various nanoparticles to provide color. Once stretched, the material becomes translucent and its composition changes. Previously disorganized carbon chains reform as parallel lines, which are much better at conducting heat.</p> <p>While these polymers need further development for use in transparent windows, they could possibly be used in colorful, translucent windows that reflect or trap heat, ultimately leading to energy savings. “The material isn’t as transparent as glass, but it’s translucent. It could be useful for windows in places you don’t want direct sunlight to enter — like gyms or classrooms,” Boriskina adds.</p> <p>Boriskina is also using these materials for military applications. Through a three-year project funded by the U.S. Army, she is developing lightweight, custom-colored, and unbreakable polymer windows. These windows can provide passive temperature control and camouflage for portable shelters and vehicles.</p> <p>For any of these technologies to have a meaningful impact on energy consumption, researchers must improve scalability and affordability. “Right now, the cost barrier for these technologies is too high — we need to look into more economical and scalable versions,” Fang adds.&nbsp;</p> <p>If researchers are successful in developing manufacturable and affordable solutions, their window technologies could vastly improve building efficiency and lead to a substantial reduction in building energy consumption worldwide.</p> A smart window developed by Professor Nicholas Fang includes thermochromic material that turns frosty when exposed to temperatures of 32 C or higher, such as when a researcher touches the window with her hand. Photo courtesy of the researchers.Mechanical engineering, School of Engineering, Materials Science and Engineering, Energy, Architecture, Climate change, Glass, Nanoscience and nanotechnology Professor Emeritus Ali Argon, pioneer in the mechanics of materials, dies at 89 Longtime MIT professor was a world leader in inelastic deformation and fracture of engineering materials. Fri, 03 Jan 2020 15:30:01 -0500 Mary Beth Gallagher | Department of Mechanical Engineering <p>Ali S. Argon SM '53, ScD '56, the Quentin Berg Emeritus Professor of Mechanical Engineering, passed away on Dec. 21, 2019, at the age of 89. A world-leading expert in the mechanics of materials, Argon’s pioneering research furthered the field’s understanding of inelastic deformation and fracture of materials including metals and alloys, ceramics, glasses, polymers, and composites.</p> <p>Argon was born in 1930 in Istanbul, Turkey, to a Turkish father and a German mother. After completing high school in Turkey, Argon moved to the United States, where he obtained a bachelor of science degree from Purdue University in 1952. He then enrolled in graduate school at MIT, where he studied materials science under Professor Egon Orowan. Argon received his master’s degree in mechanical engineering from MIT in 1953 and his doctoral degree in 1956. His doctoral thesis examined the strength and anelasticity of glass.</p> <p>After receiving his doctorate, Argon spent two years working on Van de Graaf particle accelerators for both research and medical applications at the High Voltage Engineering Corporation in Burlington, Massachusetts. He then returned to Turkey in 1958 to serve in the Turkish Army Ordnance Corps.</p> <p>In 1960, after two years of military service, Argon returned to MIT, having accepted a faculty position in mechanical engineering. By 1968, he was named a full professor. In 2001, Argon was named the Quentin Berg Professor of Mechanical Engineering at MIT.</p> <p>Throughout his career, Argon combined novel experiments with theoretical and computational modeling to deepen the understanding of inelastic deformation and fracture of engineering materials. His research shed light on the connections between microstructure and macroscopic deformation and failure properties of engineering solids.</p> <p>Having published 335 research works, Argon is one of the most-cited researchers in the field of mechanics of materials. Along with co-author Frank A. McClintock, he wrote the seminal text “Mechanical Behavior of Materials” (Addison-Wesley, 1966). As one of the first books to provide an overview of the mechanical behavior of metals as well as ceramics, rubbers, and polymers, many consider the work as the beginning of the mechanics and materials field.&nbsp;&nbsp;</p> <p>In addition to his impactful research contributions, Argon was a dedicated educator throughout his career at MIT. He mentored over 30 doctoral students, many of whom have gone on to become leading experts in the field. In the mid-1990s, Argon helped reshape the graduate program in mechanical engineering at MIT by leading an ad hoc committee. Under his leadership, the committee put forth recommendations for graduate programs designed for students interested in pursuing careers in industry.</p> <p>Argon received numerous awards and honors in recognition for his research contributions. In 1989, he was elected to the National Academy of Engineering for “major contributions to the understanding of deformation and fracture of engineering materials through the application of mechanics to microstructure." He was also made a fellow of the American Physical Society. Among his many awards are the ASME Nadai Medal, ETH’s Staudinder Durrer Medal, and the Heyn Medal of the German Materials Society. In 2005 he received an honorary doctoral degree from his alma mater, Purdue University.</p> <p>Argon is survived by his wife, Xenia (nee Lacher), and his son, Kermit. He was predeceased by his daughter, Alice, in 2015.</p> Professor Emeritus Ali Argon, Quentin Berg Emeritus Professor of Mechanical Engineering (1930-2019)Photo: John FreidahMechanical engineering, School of Engineering, Materials Science and Engineering, Obituaries, Faculty, Alumni/ae, Mentoring, DMSE Jeffrey Grossman named head of the Department of Materials Science and Engineering Materials engineering and energy expert to succeed Chris Schuh. Thu, 26 Dec 2019 11:00:01 -0500 School of Engineering <p>Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems and a MacVicar Faculty fellow, has been appointed the new head of the Department of Materials Science and Engineering effective Jan. 1, 2020.</p> <p>Grossman received his PhD in theoretical physics from the University of Illinois and performed postdoctoral work at the University of California at Berkeley. He was a Lawrence Fellow at the Lawrence Livermore National Laboratory and returned to Berkeley as director of a Nanoscience Center and head of the Computational Nanoscience research group, with a focus on energy applications. In fall 2009, he joined MIT, where he has developed a research program known for its contributions to energy conversion, energy storage, membranes, and clean-water technologies.</p> <p>Grossman’s passion for teaching and outstanding contributions to education are evident through courses such as 3.091 (Introduction to Solid-State Chemistry) — within which Grossman applies MIT’s “mens-et-manus”&nbsp;(mind-and-hand) learning philosophy. He uses “goodie&nbsp;bags” containing tools and materials that he covers in his lectures, encouraging hands-on learning and challenging students to ask big questions, take chances, and collaborate with one another.</p> <p>In recognition of his contributions to engineering education, Grossman was named an MIT MacVicar Faculty Fellow and received the Bose Award for Excellence in Teaching, in addition to being named a fellow of the American Physical Society. He has published more than 200 scientific papers, holds 17 current or pending U.S. patents, and recently co-founded a company, Via Separations, to commercialize graphene-oxide membranes.</p> <p>“Professor Grossman has done remarkable work in materials science and engineering, in particular energy conversion, energy storage, and clean-water technologies,” says Anantha Chandrakasan, dean of the MIT School of Engineering and the Vannevar Bush Professor of Electrical Engineering and Computer Science. “He has demonstrated exceptional commitment and vision as an educator. I am thrilled that he will be serving as the new head of our materials science and engineering department, and know he will be a tremendous leader.”</p> Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems and a MacVicar Faculty Fellow, has been appointed the new head of the Department of Materials Science and Engineering. Image: M. Scott BrauerMaterials Science and Engineering, School of Engineering, MacVicar fellows, Faculty, DMSE, Administration Widening metal tolerance for hydrogels MIT graduate student Seth Cazzell shows controlling pH enables reversible hydrogel formation in wider range of metal concentrations. Mon, 23 Dec 2019 15:55:01 -0500 Denis Paiste | Materials Research Laboratory <p>Researchers seeking to develop self-healing hydrogels have long sought to mimic the natural ability of mussels to generate strong, flexible threads underwater that allow the mussels to stick to rocks.</p> <p>The natural process that gives these mussel threads, which are called byssal, the ability to break apart and re-form is a purely chemical process, not a biological one, MIT graduate student Seth Cazzell noted in a presentation to the Materials Research Society fall meeting in Boston on Dec. 5.</p> <p>The critical step in the process is the chemical binding of polymer chains to a metal atom (a protein-to-metal bond in the case of the mussel). These links are called cross-linked metal coordination bonds. Their greatest strength occurs when each metal atom binds to three polymer chains, and they form a network that results in a strong hydrogel.</p> <p>In a recently published&nbsp;<em>PNAS</em>&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">paper</a>, Cazzell and associate professor of materials science and engineering&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Niels Holten-Andersen</a>&nbsp;demonstrated a method to create a self-healing hydrogel in a wider range of metal concentrations through the use of competition controlled by the pH, or acidity and alkalinity, of the environment. Cazzell is a former National Defense Science and Engineering Graduate Fellow.</p> <p>In their model computational system, Cazzell showed that in the absence of pH-controlled competition, excess metal — typically iron, aluminum, or nickel — overwhelms the ability of the polymer to form strong cross-links. In the presence of too much metal, the polymers will bind singly to metal atoms instead of forming cross-linked complexes, and the material remains a liquid.</p> <div class="cms-placeholder-content-video"></div> <p>One commonly studied mussel-inspired metal coordinating ligand is catechol. In this study, a modified catechol, nitrocatechol, was attached to polyethylene glycol. By studying the nitrocatechol system coordinated with iron, as well as a second model hydrogel system (histidine coordinated with nickel), Cazzell experimentally confirmed that the formation of strong cross-links could be induced under excess metal concentrations, supporting their computational evidence of the competitive role of hydroxide ions (negatively charged hydrogen-oxygen pairs), which act as a competitor to the polymer for binding to metal.</p> <p>In these solutions, polymers can bind to metal atoms in ones, twos, or threes. When more metal atoms bind to the hydroxide ions, there are fewer metal atoms available to bind to polymer atoms, which increases the likelihood that the polymer atoms will bind to the metal atoms in strong triple cross-links that produce the desired putty-like gel.</p> <p>“What we really like about this study is we’re not looking at biology directly, but we think it’s giving us nice evidence of something that might be happening in biology. So it’s an example of materials science informing what we think the organism is actually using to build these materials,” Cazzell says.</p> <p>In simulations, Cazzell plotted the effect of the hydroxide competitor on strong hydrogel formation and found that as competitor strength increases, “we can enter into a range where we can form a gel almost anywhere.” But, he says, “Eventually the competitor gets too strong, and you lose the ability to form a gel at all.”</p> <p>These results have potential for use in advanced 3D printing of synthetic tissues and other biomedical applications.</p> <p>This work was supported by the National Science Foundation through the MIT Materials Research Laboratory’s Materials Research Science and Engineering Center program, and by the U.S. Office of Naval Research.</p> Inspired by tissue that keep mussels attached to rocks underwater, MIT graduate student Seth Cazzell (pictured) and Associate Professor Niels Holten-Andersen found that controlling pH enables reversible hydrogel formation.Photo: Denis Paiste/Materials Research LaboratoryMaterials Research Laboratory, Materials Science and Engineering, Hydrogels, Metals, DMSE, Research, Bioinspiration, School of Engineering Workshop connects microscale mechanics to real-world alloy design “Micromechanics informed alloy design: Overcoming scale-transition challenges” focuses on bridging scale gaps. Tue, 17 Dec 2019 14:45:01 -0500 Materials Research Laboratory <p>New micro- and nanomechanical tests reveal the behavior of metal alloys at the micro- and nanoscale, but integrating these findings into engineering-scale metal-alloy designs and products remains a challenge.&nbsp;</p> <p>“I can go and test a tiny volume of a metal to learn about how it behaves.&nbsp;This is very interesting because it gives us insight about some of the fundamental characteristics of material, because as you can imagine, if you are probing smaller and smaller volumes, then you look at simpler and simpler structures,” says <a href="">C. Cem Taşan</a>, associate professor of metallurgy.&nbsp;</p> <p>“Still, at the macro world — the alloys, the materials that we all use — they have complicated microstructures. They are not simple at all,” he says. “The big challenge is, how do I connect the world of grains and atoms at the micro and nano scale to the deformations and crashes and impacts at the engineering macro scale.”</p> <p>More than 50 students and professors from multiple departments and universities, as well as representatives from industry, participated in the third annual <a href="">Alloy Design Workshop</a> at MIT on Dec. 6. The workshop, titled “Micro-mechanics informed alloy design: Overcoming scale-transition challenges,” focused on bridging scale gaps, enabling complex alloy design through the understanding of fundamental nano-scale mechanisms of plasticity and fracture mechanics. This year’s workshop sponsors were Allegheny Technologies Incorporated (<a href="">ATI</a>) and ExxonMobil.<br /> &nbsp;&nbsp;&nbsp; &nbsp;<br /> “There are specific challenges associated with carrying this information that is from the micro and nano scale to the engineering world, the scale you and I can see with our eye. That’s why we invited eight leading professors in the world to give talks,” Taşan says. The workshop ended with a panel discussion that included professors Timothy P. Weihs from Johns Hopkins University, Amy Clarke from Colorado School of Mines, Mitra Taheri from Johns Hopkins University, Sharvan Kumar from Brown University, Thomas Bieler from Michigan State University, and Motomichi Koyama from Tohoku University.</p> <p>In her presentation, Clarke described her work studying solidification of materials such as <a href="">aluminum-copper alloy melts</a>. This real-time imaging with synchrotron X‐rays allows her to map out the processing space. These experiments also provide information that had been missing in aluminum copper alloy simulations, or models, she noted.&nbsp;</p> <p>Humankind has been working metal for 4,000 years, mostly by trial-and-error up until the scientific age. “For some students, they may have the feeling maybe there isn’t so much new to be said in this field, a field that is thousands of years old,” Taşan observes. Yet, metals remain central to modern transportation, building, packaging, and many other key industries. “There is no projection I can think of in the near future where metals dominance in these structural applications is going to be significantly reduced,” Taşan notes. While newer composite materials may replace some metal components, “There is not a huge change coming, as we still need the properties metallic materials exhibit.”</p> <p>Taşan noted what Apple Materials Engineering Director Jim Yurko spoke about in his recent Wulff lecture at MIT. “Why is a company that produces phones and computers interested in casting and heat treatment of aluminum alloys, to optimize their microstructure and precipitation?” Taşan asks. “Because they use aluminum and they need to somehow produce it, and solve the small problems with it. We do not always realize it, but metals are widely incorporated in most engineering products around us.”</p> <p>“It’s very interesting that in this field — metallurgy and alloy design&nbsp;— challenges and solutions are distributed widely,” Taşan says. “In a single day, I may meet with a person from the jewelry industry and then somebody from the trucking or automotive industries. Very different materials, similar problems, and they all want solutions to their problems.”&nbsp;</p> <p>Car and truck makers seek steel designs that are higher in strength, because stronger steel allows them to use less steel, which lightens vehicles and cuts fuel consumption. “But there is an interesting dilemma,” Taşan says. “Typically, if you make a material stronger, it becomes more susceptible to cracking and fracture. You can increase strength, but the more you increase strength, the less you can form complex shapes during manufacturing.</p> <p>“This is an ongoing challenge. Researchers have been looking for different chemistries, different processing cycles, to be able to create microstructures that give both strength and ductility,” he says.</p> <p>Taşan created the Alloy Design Workshops to emphasize the continued importance of alloy design in modern materials science. The workshop is held each year on the last day of the Materials Research Society Fall Meeting in Boston, Massachusetts, to provide an opportunity for the MIT community and the materials community as a whole to congregate in an intimate setting to present and discuss new, unpublished research.</p> <p><a href="">Previous workshops</a> covered the topics of “New guidelines in alloy design: From atomistic simulations to combinatorial metallurgy” and “Sustainability through alloy design: Challenges and opportunities.”</p> Attendees joined a group photo at the 2019 MIT Alloy Design Workshop, which focused on bridging scale gaps, enabling complex alloy design through the understanding of fundamental nanoscale mechanisms of plasticity and fracture mechanics.Photo courtesy of Tasan Group.Materials Research Laboratory, Materials Science and Engineering, Metals, School of Engineering, Special events and guest speakers, Nanoscience and nanotechnology Making buildings from industrial waste Following a successful project creating bricks from pulp plant waste in northern India, Elsa Olivetti is looking for ways to repurpose slag produced by the metals industry. Mon, 16 Dec 2019 13:15:01 -0500 Rachel Fritts | Environmental Solutions Initiative <p>Elsa Olivetti’s interest in materials science began when she was an engineering science major at the University of Virginia. Initially unable to settle on any one form of engineering, she took an introduction to materials science class on a whim. She loved the way materials science let her examine everyday material, like a block of wood or piece of cloth, on a molecular level. “Being able to think across those scales is something that I found really cool,” Olivetti says.</p> <p>Now, Olivetti is an associate professor in the MIT Department of Materials Science and Engineering and the principal investigator of her own lab. Her interest has turned to the social and environmental impacts of the materials we use in our daily lives. Specifically, the Olivetti lab looks at the huge quantities of industrial waste materials generated in the manufacturing industry, in the hopes of finding useful ways to reconstitute and reuse this waste for building.</p> <p>Some types of waste have already become standard tools in the building industry: fly ash from burning coal, for instance, is increasingly used in concrete as a substitute for freshly produced cement. Most types of industrial waste, however, are simply discarded as useless byproducts. Olivetti hopes to change that. By applying her understanding of materials on a molecular level, she can propose new ways these byproducts might be integrated into usable building materials to make the industry more efficient.</p> <p>Several years ago, Olivetti was able to put that idea to the test by participating in a Tata Center project launched in a city called Muzaffarnagar in northern India. The area is highly industrial, containing pulp and paper mills and steel and brick manufacturers. “But the challenge there is they don’t have a lot of resources to put into environmental abatement,” Olivetti says. “They’re just dumping.”</p> <p>So, the Tata Center team went looking for byproducts that could potentially be put to another use. They noticed that the pulp plants were powered by sugar cane and rice husks, which were burned to generate energy. The byproduct of these burnt plant materials was something called “biomass ash,” which has “pretty high, fairly reactive silica content.” This means that it can bind with other materials to produce a strong, cement-like structure.</p> <p>They were able to demonstrate that this ash, which had previously been dumped as waste, could actually be turned into cheap building material, providing an economic and environmental benefit to the local community. The end result, produced in 2015, was dubbed the Eco-BLAC brick. In 2017, Olivetti received an Environmental Solutions Initiative (ESI) seed grant to continue this work back at MIT.</p> <p>“What we used the ESI money for is to move outside of biomass ash and into other materials,” Olivetti says. She summarizes the work as “beyond India, beyond ash.” She’s most interested in the kinds of materials where “there’s still enough quantity to make it useful, but they aren’t already well-utilized,” a rubric that has brought her focus to metal waste products, especially the “slag” left over during copper production.</p> <p>Olivetti is particularly fond of the ESI project because “it pulls together a bunch of different dimensions of what I like to think about.” When trying to understand which metal waste materials might be put to the best use, she has to ask a few key questions. First, is the waste material reactive, like the biomass ash material was? Can it bind with other materials to add strength and integrity? How reactive is it? What will it react with, and under what conditions? Or, is the material non-reactive? Non-reactive materials don’t necessarily add value, but can be used to add volume, just as sand is mixed with cement to produce concrete.</p> <p>Once she figures out what role the material might play, she has to understand its durability in the environment where it will be used. Biomass ash, for instance, has a lot of carbon, and one implication of this is that it takes in water. This might not be a problem in India, where it is warm year-round, but it can harm the structural integrity of a material that will be used somewhere like Boston, Massachusetts, where winter temperatures drop below freezing.</p> <p>To test all these things, she needs to do something a little bit counterintuitive. “One of the things we’ve started to do, which has been kind of fun, is synthesize waste,” she says. “Which feels silly when I say it like that.”</p> <p>A recurring problem with researching waste is that it involves substances people have typically ignored. It’s rare for any industry to keep careful track of what its waste is made up of, or how much of it is produced. When making copper, for instance, the end product is always copper. But there might be several different kinds of unintended waste products that are produced along the way, which all get mixed together. Olivetti describes the end result as “Jell-O with a bunch of fruit in it.”</p> <p>By artificially manufacturing the waste, Olivetti can better understand how much of each waste product is produced, and how to best separate it into usable materials. The question of quantity is another one that becomes trickier to answer when dealing with waste material. While a steel factory, for example, has an incentive to measure its steel production, it has little incentive to keep detailed records of how much material it’s wasting.</p> <p>“I think overall what this field needs is better cataloging of what wastes are going to be where, and trying to project that a little bit,” Olivetti says. “If it’s a raw material for making something, you need to know that supply’s going to be steady.” A key component of any business is having a stable supply, so in order for all this waste material to be used more widely, there need to be better records of what kinds of waste are being produced where, and in what quantity. Now, Olivetti is working on a project using AI to automatically extract information about how various materials are made, to try to better understand the supply chain and where the most promising byproducts are being created.</p> <p>She’s also hoping to better understand the environmental impact of using waste materials, to ensure that there will be no harmful effects of repurposing these substances. If even one of the Olivetti lab’s discoveries is widely adopted, her research will have contributed to a materials supply chain that is much more efficient, cost-effective, and environmentally sustainable than ever before.</p> Associate Professor Elsa Olivetti studies the huge quantities of industrial waste materials generated in the manufacturing industry, in hopes of finding useful ways to reconstitute and reuse this waste for building.Photo: MIT Environmental Solutions InitiativeMaterials Science and Engineering, Tata Center, School of Engineering, Environment, Supply chains, Sustainability, Recycling, Industry, DMSE, Profile, Faculty, India Using online, game-based simulations to train photonic technicians and engineers MIT wins $5 million grant to develop a virtual lab that will prepare students for jobs in industry and government. Thu, 12 Dec 2019 12:50:01 -0500 Julie Diop | Department of Materials Science and Engineering <p>For more than 150 years, MIT has revolutionized scientific and engineering education, which in turn has driven industrial innovation. Early students were the first to experience hands-on education, rather than learning by rote, and to travel to practice schools. Recently, MIT has added ambitious online learning initiatives, offered both to the MIT community and, through edX, to the world. Increasingly, MIT is leading the creation of curricula that combine online and in-person training — a perfect combination of traditional and contemporary educational tools.&nbsp;&nbsp;</p> <p>The rapidly evolving field of integrated photonics — a technology that shrinks signals of light to the sub-micron scale and funnels them into light-guiding circuits — entails designing, fabricating, packaging, and testing novel photonic microchips. Companies are eager to hire technicians and engineers but need help training an inexperienced workforce.&nbsp;</p> <p>The solution: create game-based interactive learning simulations.</p> <p>The U.S. Office of Naval Research’s Manufacturing Engineering Education Program awarded Thomas Lord Professor of Materials Science and Engineering Lionel Kimerling’s group, the MIT Education Arcade, and MIT’s Office of Open Learning a $5 million, three-year grant to develop multimedia online training modules around simulations of photonic integrated circuit components. Cloud computing data centers, self-driving cars, and medical diagnostic chips use these state-of-the-art chips. Kimerling is also education and workforce executive of AIM Photonics Institute, and as part of his work with AIM Photonics, he oversaw the development of simulation prototypes used in an <em>MITx</em> course this spring, enabling students to see how changes in photonic device design affect the propagation and confinement of light signals.&nbsp;&nbsp;</p> <p>“Games allow students to explore, and make both good and bad design decisions,” says Kimerling. “They prepare students to tackle real-world applications, supplementing what they learn experimenting in labs and using large software packages.”&nbsp;</p> <p>The Virtual Lab, Kimerling says, will help build students’ knowledge and prepare them for jobs in industry and government.</p> <p>MIT has teamed up with Clemson University and the University of Arizona on this grant. The Clemson University Center for Workforce Development has years of experience creating learning modules using virtual reality simulations for education in robotics and aviation, and Clemson launched, an online platform for manufacturing workforce training that includes a library of learning modules. The College of Optical Sciences at the University of Arizona provides distance education in optics and photonics for students worldwide. Some of the simulations developed in the collaboration will be hosted on the site. Kimerling’s group and MIT Open Learning will work closely to systematically field test and assess student engagement with simulations in new upcoming integrated photonics <em>MITx</em> courses. “We have the potential to give students tools that I could only dream of when I was in school,” says Erik Verlage, a postdoc in Kimerling’s group who will help lead the project.&nbsp;&nbsp;&nbsp;&nbsp;</p> <p>AIM Photonics Institute is one of 14 public-private manufacturing institutes started during the administration of U.S. President Barack Obama to spur growth in advanced manufacturing within the United States. In the third year of the new grant, the team will work with some of the other 13 manufacturing institutes’ education leads to create game-based education simulations for their unique technologies and learning goals.</p> <p>Although the primary learners in integrated photonics have been the engineers who design these light-guiding chips, the new simulations will be helpful to technicians who operate the equipment and tools to manufacture and test the chips. MIT is developing a technician-certification program with Stonehill College and Bridgewater State University, and both schools will incorporate the simulations in their lesson plans. By including a varying number of parameters in the simulations, Kimerling’s group and Eric Klopfer’s Education Arcade can customize the complexity and learning challenges of the simulations.&nbsp;</p> <p>With this grant, MIT will bring together a diverse team to make difficult science and engineering topics easier to master for the next generation of photonic practitioners.</p> Interactive training simulations use 3D virtual environments to create a playground for photonics experimentation.Image: Erik Verlage, Trevor Morrisey, and Ryan KosciolekMaterials Science and Engineering, Office of Open Learning, MITx, online learning, Photonics, Grants, DMSE, Video games, STEM education, Careers, School of Engineering Taking the carbon out of construction with engineered wood Substituting lumber for materials such as cement and steel could cut building emissions and costs. Wed, 11 Dec 2019 12:55:01 -0500 Mark Dwortzan | Joint Program on the Science and Policy of Global Change <p>To meet the long-term goals of the Paris Agreement on climate change — keeping global warming well below 2 degrees Celsius and ideally capping it at 1.5 C — humanity will ultimately need to achieve net-zero emissions of greenhouse gases (GHGs) into the atmosphere. To date, emissions reduction efforts have largely focused on decarbonizing the two economic sectors responsible for the most emissions, electric power and transportation. Other approaches aim to remove carbon from the atmosphere and store it through carbon capture technology, biofuel cultivation, and massive tree planting. &nbsp;</p> <p>As it turns out, planting trees is not the only way forestry can help in climate mitigation; how we use wood harvested from trees may also make a difference. Recent studies have shown that engineered wood products — composed of wood and various types of adhesive to enhance physical strength — involve far fewer carbon dioxide emissions than mineral-based building materials, and at lower cost. Now <a href="" target="_blank">new research</a> in the journal <em>Energy Economics</em> explores the potential environmental and economic impact in the United States of substituting lumber for energy-intensive building materials such as cement and steel, which account for <a href="" target="_blank">nearly 10 percent</a> of human-made GHG emissions and are among the hardest to reduce.</p> <p>“To our knowledge, this study is the first economy-wide analysis to evaluate the economic and emissions impacts of substituting lumber products for more CO<sub>2</sub>-intensive materials in the construction sector,” says the study’s lead author <a href="">Niven Winchester</a>, a research scientist at the MIT Joint Program on the Science and Policy of Global Change and Motu Economic and Public Policy Research. “There is no silver bullet to reduce GHGs, so exploiting a suite of emission-abatement options is required to mitigate climate change.”</p> <p>Comparing the economic and emissions impacts of replacing CO<sub>2</sub>-intensive building materials (e.g., steel and concrete) with lumber products in the United States under an economy-wide cap-and-trade policy consistent with the nation’s Paris Agreement GHG emissions-reduction pledge, the study found that the CO<sub>2</sub> intensity (tons of CO<sub>2</sub> emissions per dollar of output) of lumber production is about 20 percent less than that of fabricated metal products, under 50 percent that of iron and steel, and under 25 percent that of cement. In addition, shifting construction toward lumber products lowers the GDP cost of meeting the emissions cap by approximately $500 million and reduces the carbon price.</p> <p>The authors caution that these results only take into account emissions resulting from the use of fossil fuels in harvesting, transporting, fabricating, and milling lumber products, and neglect potential increases in atmospheric CO<sub>2</sub> associated with tree harvesting or beneficial long-term carbon sequestration provided by wood-based building materials.</p> <p>“The source of lumber, and the conditions under which it is grown and harvested, and the fate of wood products deserve further attention to develop a full accounting of the carbon implications of expanded use of wood in building construction,” they write. “Setting aside those issues, lumber products appear to be advantageous compared with many other building materials, and offer one potential option for reducing emissions from sectors like cement, iron and steel, and fabricated metal products — by reducing the demand for these products themselves.”</p> <p>Funded, in part, by Weyerhaeuser and the Softwood Lumber Board, the study develops and utilizes a customized economy-wide model that includes a detailed representation of energy production and use and represents production of construction, forestry, lumber, and mineral-based construction materials.</p> A 70-unit British Columbia lakeside resort hotel was built with local engineered wood products, including cross-laminated timber. New research explores the potential environmental and economic impact in the United States of substituting lumber for energy-intensive building products such as cement and steel.Photo: Province of British Columbia/FlickrResearch, Climate change, Greenhouse gases, Emissions, Climate, Environment, Energy, Economics, Policy, Carbon dioxide, Building, Sustainability, Materials Science and Engineering, Cement, Joint Program on the Science and Policy of Global Change Planning for death, as a way to improve life Startup co-founded by alumna Suelin Chen helps people share their end-of-life wishes with loved ones. Fri, 06 Dec 2019 12:58:14 -0500 Zach Winn | MIT News Office <p>Losing a loved one is always hard, but honoring their final wishes can provide a sense of fulfillment in the midst of grief. However, many people avoid thinking about their own death, even if they believe it’s a long way off, and thus don’t share their posthumous preferences with friends and family.</p> <p>End-of-life planning startup Cake is trying to change that. The company is borne out of the idea that planning for death now can make things a lot easier for loved ones down the line.</p> <p>Cake breaks down what can be an overwhelming process into a series of simple questions to help people make decisions around health care treatments, funeral arrangements, estate planning, and how they want to be remembered after they’re gone.</p> <p>“Ignoring the fact that we’re all mortal is not helping anyone, and you can actually use the fact that life is finite as a positive and motivating force, and as a way to cultivate gratitude,” says Cake co-founder and CEO Suelin Chen ’03 SM ’07 PhD ’10.</p> <p>Most people agree that the questions Cake asks have important answers, but those questions are often left to family and friends who must try their best to honor a loved one’s wishes. Among the many options Cake offers, users can decide who can make care decisions on their behalf, whether or not to get life insurance, what to do with their social media accounts after they’re gone, and who they want (or don’t want) at their funeral.</p> <p>“The space and services are very fragmented, so we bring it all together in one place,” Chen says. “We say ‘Here are all the areas you want to think about,’ because people don’t know what they don’t know. We then guide you on the things you should be doing, store all of that online securely in your profile, and enable you to share it with the important people in your life.”</p> <p>Chen says using Cake is a simple and thought-provoking experience that can give people peace of mind.</p> <p>“People are really surprised that you can make a topic like death interesting and reflective, and also illuminating and positive,” Chen says. “What you want for end-of-life is actually just what is important to you in life. With the name Cake, we’re really trying to emphasize the fact that end-of-life planning is a positive act, a gift. You want to honor your life and the life of those you love. Cake is a symbol of celebrating life milestones, and even though losing someone is always hard, thinking about death in and of itself is not inherently negative.”</p> <p>Cake has already partnered with life insurance companies, health care organizations, and financial institutions to offer its services to their customers. Now, it’s expanding to help individuals with their end-of-life plans. The progress is exciting for Chen, whose commitment to impact has led her down an unconventional path to entrepreneurship.</p> <p><strong>A researcher with a mission</strong></p> <p>In the 2000s, Chen spent nearly a decade at MIT earning her degrees, studying biology and biomedical engineering as an undergraduate before earning her master’s and PhD in MIT’s Department of Materials Science and Engineering. During that time, Chen never once took a business or entrepreneurship class.</p> <p>“I had no aspirations to be an entrepreneur, but I wanted to have a positive impact on the world, and I thought health care was the best way to do that,” Chen says. “I also liked engineering, so I felt like the best way to use my skills was not to be a doctor, but to use engineering to solve problems in health care.”</p> <p>After completing her PhD in 2010, Chen became the director of The Laboratory at Harvard, an interdisciplinary program that emphasizes learning through real-world experimentation, where she says she “caught the business bug.”</p> <p>“Business is how you get these ideas into the world to touch real people and have a real impact,” Chen says.</p> <p>In 2014, Chen decided to attend the MIT Hacking Medicine Grand Hack. When she registered for the event, she shared her idea of using technology to improve people’s circumstances around the end of their life. Also attending the event that day was Mark Zhang, a palliative care physician and technologist, who suggested to Chen they team up. The pair ended up winning first place, and continued researching ways to address people’s anxiety about planning for the end of life.</p> <p>“Eventually we all die, and it didn’t really seem like anyone was paying attention to that,” Chen says. “It’s a part of the human experience that every single person goes through. Everyone experiences loss in their life, and I just kept coming back to, ‘Why is that experience still so bad even though we’re pouring so much money into the end of life, especially from a health care perspective?’”</p> <p>Chen returned to MIT occasionally to get guidance from the Venture Mentoring Service, and she says her MIT ties have helped immensely in her transition from a researcher to a founder.</p> <p>“I’ve emailed MIT [VMS] mailing lists many times, and I’m constantly talking to friends from MIT who are entrepreneurs,” Chen says. “So many of my classmates have started companies. When you’re an entrepreneur, having the MIT network is incredible.”</p> <p><strong>Thinking about life to plan for death</strong></p> <p>Chen and Zhang initially thought their service would be most useful for people closer to the end of their lives, but their early testing dispelled that idea.</p> <p>“There’s really complex psychology about how people engage with their mortality, and just because you are close to death doesn’t mean you’re going to be amenable to thinking about it,” Chen says. “Conversely, young, healthy people were really interested in what we were doing.”</p> <p>Chen says millennials are Cake’s second-biggest customer demographic. She guesses that’s because they are starting families, worried about aging parents, or are simply pragmatic and curious about their mortality. Also, instead of doing planning solely on paper, they may be expecting technology to help them with this task.</p> <p>Indeed, Cake’s questions address major concerns, like ensuring protection for planners’ dependents, and matters that have more to do with personal taste, like whether or not loved ones should plant a tree in the planner’s memory. (Sixty-seven percent of respondents say yes.) Chen says one of the most popular topics is the kind of music planners’ want played at their funeral.</p> <p>“We absolutely understand this is a hard topic for most people, so we are focused on getting the barrier to entry as low as possible, and getting people normalized to even thinking about death and dying,” Chen says. “What we’re trying to do is make it easier for people to think about what they’d want for end-of-life and to share that information with their loved ones, and also make it easier to know what their loved ones want.”</p> <p>Chen did not disclose information on Cake’s enterprise customers or the number of people using its services, but she says someone answers a question about their end-of-life preferences every five minutes on Cake’s platform, which is free for users.</p> <p>The momentum is a form of vindication for Chen, who as CEO has spent the last four years raising awareness of a topic that many people would prefer to ignore. In the midst of building Cake’s solution and securing early customers, with Chen immersed in the details of death, she also received a crash course in life, having two children who are both still under the age of three. She sees many parallels between how people enter and exit life, and believes that the same amount of thought and consideration should go into both events.</p> <p>“[Cake] is about people getting a sense for what’s important to them in life and communicating that to their loved ones,” Chen says. “That’s what it’s all about.”</p> Cake's end of life planning service breaks down what can be an overwhelming process into a series of simple questions to help people make decisions around health care treatments, funeral arrangements, estate planning, and how they want to be remembered after they’re gone.Courtesy of CakeInnovation and Entrepreneurship (I&E), Startups, School of Engineering, DMSE, Materials Science and Engineering, Health care, Hackathon, Alumni/ae Two MIT professors named 2019 fellows of the National Academy of Inventors Li-Huei Tsai and Christopher Schuh recognized for research innovations addressing Alzheimer’s disease and metal mechanics. Tue, 03 Dec 2019 10:00:01 -0500 David Orenstein | Picower Institute <p>The National Academy of Inventors has selected two MIT faculty members, neuroscientist Li-Huei Tsai and materials scientist Christopher Schuh, as members of its 2019 class of new fellows.</p> <p>NAI fellows “have demonstrated a highly prolific spirit of innovation in creating or facilitating outstanding inventions that have made a tangible impact on the quality of life, economic development and welfare of society,” the organization stated in its announcement.</p> <p>Schuh is the department head and the Danae and Vasilis Salapatas Professor of Metallurgy in the Department of Materials Science and Engineering. His&nbsp;research is focused on structural metallurgy and seeks to control disorder in metallic microstructures for the purpose of optimizing mechanical properties; much of his work is on the design and control of grain boundary structure and chemistry.</p> <p>Schuh has published dozens of patents and co-founded a number of metallurgical companies. His first MIT spinout company, Xtalic Corporation, commercialized a process from his MIT laboratory to produce stable nanocrystalline coatings, which have now been deployed in over 10 billion individual components in use worldwide. Schuh’s startup Desktop Metal is a metal additive manufacturing company developing 3D metal printers that are sufficiently simpler and lower-cost than current options to enable broad use across many industries. Recently, Schuh co-founded Veloxint Corporation, which is commercializing machine components made from custom stable nanocrystalline alloys designed in his MIT laboratory.</p> <p>Tsai, the Picower Professor of Neuroscience and director of the Picower Institute for Learning and Memory, focuses on neurodegenerative conditions such as Alzheimer’s disease. Her work has generated a dozen patents, many of which have been licensed by biomedical companies including two startups, Cognito Therapeutics and Souvien Bio Ltd., that have spun out from her and collaborator’s labs.</p> <p>Her team’s innovations include inhibiting an enzyme that affects the chromatin structure of DNA to rescue gene expression and restore learning and memory, and using light and sound stimulation to enhance the power and synchrony of 40-hertz gamma rhythms in the brain to reduce Alzheimer’s pathology, prevent neuron death, and preserve learning and memory. Each of these promising sets of findings in mice are now being tested in human trials.</p> <p>Tsai and Schuh join 21 colleagues from MIT who have previously been elected NAI fellows.</p> Li-Huei Tsai, left, is the Picower Professor of Neuroscience and director of The Picower Institute for Learning and Memory, and Christopher Schuh, is department head and the Danae and Vasilis Salapatas Professor of Metallurgy in the Department of Materials Science and Engineering.Photos courtesy of the Picower Institute and the Department of Materials Science and EngineeringDMSE, Picower Institute, School of Engineering, School of Science, Awards, honors and fellowships, Faculty, Brain and cognitive sciences, Innovation and Entrepreneurship (I&E), Alzheimer's, Neuroscience, Materials Science and Engineering New treatment could ease the passage of kidney stones Muscle relaxants delivered to the ureter can reduce contractions that cause pain when passing a stone. Mon, 02 Dec 2019 10:59:59 -0500 Anne Trafton | MIT News Office <p>Every year, more than half a million Americans visit the emergency room for kidney stone problems. In most cases, the stones eventually pass out of the body on their own, but the process can be excruciatingly painful.</p> <p>Researchers at MIT and Massachusetts General Hospital have now devised a potential treatment that could make passing kidney stones faster and less painful. They have identified a combination of two drugs that relax the walls of the ureter — the tube that connects the kidneys to the bladder — and can be delivered directly to the ureter with a catheter-like instrument.</p> <p>Relaxing the ureter could help stones move through the tube more easily, the researchers say.</p> <p>“We think this could significantly impact kidney stone disease, which affects millions of people,” says Michael Cima, the David H. Koch Professor of Engineering in MIT’s Department of Materials Science and Engineering, a member of MIT’s Koch Institute for Integrative Cancer Research, and the senior author of the study.</p> <p>This kind of treatment could also make it easier and less painful to insert stents into the ureter, which is sometimes done after a kidney stone is passed, to prevent the tube from becoming blocked or collapsing.</p> <p>Christopher Lee, a recent PhD recipient in the Harvard-MIT Division of Health Sciences and Technology, is the lead author of <a href="" target="_blank">the study</a>, which appears today in <em>Nature Biomedical Engineering</em>.</p> <p><strong>Local drug delivery</strong></p> <p>Kidney stones are made from hard crystals that accumulate in the kidneys when there is too much solid waste in the urine and not enough liquid to wash it out. It is estimated that about one in 10 people will have a kidney stone at some point in their lives.</p> <p>Several years ago, Cima and Brian Eisner, who co-directs the Kidney Stone Program at MGH and is also an author of the paper, began thinking about ways to improve the treatment of kidney stones. While some larger stones require surgery, the usual treatment plan is simply to wait for the stones to pass, which takes an average of 10 days. Patients are given painkillers as well as an oral medication that is meant to help relax the ureter, but studies have offered conflicting evidence on whether this drug actually helps. (There are no FDA-approved oral therapies for kidney stones and ureteral dilation.)</p> <p>Cima and Eisner thought that delivering a muscle relaxant directly to the ureter might offer a better alternative. Most of the pain from passing a kidney stone arises from cramps and inflammation in the ureter as the stones pass through the narrow tube, so relaxing the muscles surrounding the tube could help ease this passage.</p> <p>Around this time, Lee, then a new student in MIT’s Health Sciences and Technology program, met with Cima to discuss possible thesis projects and became interested in pursuing a kidney stone treatment.</p> <p>“If you look at how kidney stones are treated today, it hasn’t really changed since about 1980, and there’s a pretty substantial amount of evidence that the drugs given don’t work very well,” Lee says. “The volume of how many people this could potentially help is really exciting.”</p> <p>The researchers first set out to identify drugs that might work well when delivered directly to the ureter. They selected 18 drugs used to treat conditions such as high blood pressure or glaucoma and exposed them to human ureteral cells grown in a lab dish, where they could measure how much the drugs relaxed the smooth muscle cells. They hypothesized that if they delivered such drugs directly to the ureter, they could get a much bigger relaxation effect than by delivering such drugs orally, while minimizing possible harm to the rest of the body.</p> <p>“We found several drugs that had the effect that we expected, and in every case we found that the concentrations required to be effective were more than would be safe if given systemically,” Cima says.</p> <p>Next, the researchers used intensive computational processing to individually analyze the relaxation responses of nearly 1 billion cells after drug exposure. They identified two drugs that worked especially well, and found that they worked even better when given together. One of these is nifedipine, a calcium channel blocker used to treat high blood pressure, and the other is a type of drug known as a ROCK (rho kinase) inhibitor, which is used to treat glaucoma.</p> <p>The researchers tested various doses of this combination of drugs in ureters removed from pigs, and showed that they could dramatically reduce the frequency and length of contractions of the ureter. Tests in live pigs also showed that the treatment nearly eliminated ureteral contractions.</p> <p>For these experiments, the researchers delivered the drugs using a cystoscope, which is very similar to a catheter but has a small fiber optic channel that can connect to a camera or lens. They found that with this type of delivery, the drugs were not detectable in the animals’ bloodstream, suggesting that the drugs remained in the lining of the ureter and did not go elsewhere in the body, which would lessen the risk of potential side effects.</p> <p><strong>Ureteral relaxation</strong></p> <p>More studies are needed to determine how long the muscle relaxing effect lasts and how much relaxation would be needed to expedite stone passage, the researchers say. They are now launching a startup company, Fluidity Medicine, to continue developing the technology for possible testing in human patients.</p> <p>In addition to treating kidney stones, this approach could also be useful for relaxing the ureter to help doctors insert a ureteral stent. It could also help when placing any other kind of instrument, such as an endoscope, in the ureter.</p> <p>“The platform pairs drug delivery to the ureter. We are eager to first target muscle relaxation, and as offshoots of that, we have kidney stones, ureteral stents, and endoscopic surgery,” Lee says. “We have a bunch of other urological indications that would go through different developmental pathways but can all be hit and all have meaningful patient populations.”</p> <p>The research was funded by the MIT Institute of Medical Engineering and Science Broshy Fellowship, the MIT Deshpande Center for Technological Innovation, the Koch Institute Support (core) Grant from the National Cancer Institute, and the National Institutes of Health.</p> MIT engineers used human ureteral smooth muscle cells grown in a lab dish to identify drugs that would help to relax the muscle cells.Image: Christopher Lee and Michael CimaResearch, Materials Science and Engineering, DMSE, Koch Institute, School of Engineering, National Institutes of Health (NIH), Health science and technology, Medicine Toward more efficient computing, with magnetic waves Circuit design offers a path to “spintronic” devices that use little electricity and generate practically no heat. Thu, 28 Nov 2019 13:59:59 -0500 Rob Matheson | MIT News Office <p>MIT researchers have devised a novel circuit design that enables precise control of computing with magnetic waves — with no electricity needed. The advance takes a step toward practical magnetic-based devices, which have the potential to compute far more efficiently than electronics.</p> <p>Classical computers rely on massive amounts of electricity for computing and data storage, and generate a lot of wasted heat. In search of more efficient alternatives, researchers have started designing magnetic-based “spintronic” devices, which use relatively little electricity and generate practically no heat.</p> <p>Spintronic devices leverage the “spin wave” — a quantum property of electrons — in magnetic materials with a lattice structure. This approach involves modulating the spin wave properties to produce some measurable output that can be correlated to computation. Until now, modulating spin waves has required injected electrical currents using bulky components that can cause signal noise and effectively negate any inherent performance gains.</p> <p>The MIT researchers developed a circuit architecture that uses only a nanometer-wide domain wall in layered nanofilms of magnetic material to modulate a passing spin wave, without any extra components or electrical current. In turn, the spin wave can be tuned to control the location of the wall, as needed. This provides precise control of two changing spin wave states, which correspond to the 1s and 0s used in classical computing. A paper describing the circuit design was published today in <em>Science</em>.</p> <p>In the future, pairs of spin waves could be fed into the circuit through dual channels, modulated for different properties, and combined to generate some measurable quantum interference — similar to how photon wave interference is used for quantum computing. Researchers hypothesize that such interference-based spintronic devices, like quantum computers, could execute highly complex tasks that conventional computers struggle with.</p> <p>“People are beginning to look for computing beyond silicon. Wave computing is a promising alternative,” says Luqiao Liu, a professor in the Department of Electrical Engineering and Computer Science (EECS) and principal investigator of the Spintronic Material and Device Group in the Research Laboratory of Electronics. “By using this narrow domain wall, we can modulate the spin wave and create these two separate states, without any real energy costs. We just rely on spin waves and intrinsic magnetic material.”</p> <p>Joining Liu on the paper are Jiahao Han, Pengxiang Zhang, and Justin T. Hou, three graduate students in the Spintronic Material and Device Group; and EECS postdoc Saima A. Siddiqui.</p> <p><strong>Flipping magnons</strong></p> <p>Spin waves are ripples of energy with small wavelengths. Chunks of the spin wave, which are essentially the collective spin of many electrons, are called magnons. While magnons are not true particles, like individual electrons, they can be measured similarly for computing applications.</p> <p>In their work, the researchers utilized a customized “magnetic domain wall,” a nanometer-sized barrier between two neighboring magnetic structures. They layered a pattern of cobalt/nickel nanofilms — each a few atoms thick — with certain desirable magnetic properties that can handle a high volume of spin waves. Then they placed the wall in the middle of a magnetic material with a special lattice structure, and incorporated the system into a circuit.</p> <p>On one side of the circuit, the researchers excited constant spin waves in the material. As the wave passes through the wall, its magnons immediately spin in the opposite direction: Magnons in the first region spin north, while those in the second region — past the wall —&nbsp;spin south. This causes the dramatic shift in the wave’s phase (angle) and slight decrease in magnitude (power).</p> <p>In experiments, the researchers placed a separate antenna on the opposite side of the circuit, that detects and transmits an output signal. Results indicated that, at its output state, the phase of the input wave flipped 180 degrees. The wave’s magnitude — measured from highest to lowest peak —&nbsp;had also decreased by a significant amount.</p> <p><strong>Adding some torque</strong></p> <p>Then, the researchers discovered a mutual interaction between spin wave and domain wall that enabled them to efficiently toggle between two states. Without the domain wall, the circuit would be uniformly magnetized; with the domain wall, the circuit has a split, modulated wave.</p> <p>By controlling the spin wave, they found they could control the position of the domain wall. This relies on a phenomenon called, “spin-transfer torque,” which is when spinning electrons essentially jolt a magnetic material to flip its magnetic orientation.</p> <p>In the researchers’ work, they boosted the power of injected spin waves to induce a certain spin of the magnons. This actually draws the wall toward the boosted wave source. In doing so, the wall gets jammed under the antenna — effectively making it unable to modulate waves and ensuring uniform magnetization in this state.</p> <p>Using a special magnetic microscope, they showed that this method causes a micrometer-size shift in the wall, which is enough to position it anywhere along the material block. Notably, the mechanism of magnon spin-transfer torque was proposed, but not demonstrated, a few years ago. “There was good reason to think this would happen,” Liu says. “But our experiments prove what will actually occur under these conditions.”</p> <p>The whole circuit is like a water pipe, Liu says. The valve (domain wall) controls how the water (spin wave) flows through the pipe (material). “But you can also imagine making water pressure so high, it breaks the valve off and pushes it downstream,” Liu says. “If we apply a strong enough spin wave, we can move the position of domain wall — except it moves slightly upstream, not downstream.”</p> <p>Such innovations could enable practical wave-based computing for specific tasks, such as the signal-processing technique, called “fast Fourier transform.” Next, the researchers hope to build a working wave circuit that can execute basic computations. Among other things, they have to optimize materials, reduce potential signal noise, and further study how fast they can switch between states by moving around the domain wall. “That’s next on our to-do list,” Liu says.</p> An MIT-invented circuit uses only a nanometer-wide “magnetic domain wall” to modulate the phase and magnitude of a spin wave, which could enable practical magnetic-based computing — using little to no electricity.Image courtesy of the researchers, edited by MIT NewsResearch, Computer science and technology, Nanoscience and nanotechnology, Spintronics, electronics, Energy, Quantum computing, Materials Science and Engineering, Design, Research Laboratory of Electronics, Electrical Engineering & Computer Science (eecs), School of Engineering School of Engineering third quarter 2019 awards Faculty members recognized for excellence via a diverse array of honors, grants, and prizes over the last quarter. Wed, 27 Nov 2019 11:35:01 -0500 School of Engineering <p>Members of the MIT engineering faculty receive many awards in recognition of their scholarship, service, and overall excellence. Every quarter, the School of Engineering publicly recognizes their achievements by highlighting the honors, prizes, and medals won by faculty working in our academic departments, labs, and centers.</p> <p>Richard Braatz, of the Department of Chemical Engineering, won the <a href="">AIChE 2019 Separations Division Innovation Award</a> on Oct. 1.</p> <p>Michael Carbin, of the Department of Electrical Engineering and Computer Science, <a href="">won the Best Paper Award</a> at the International Conference on Learning Representations on May 8. He also <a href="">won the Distinguished Paper Award</a> at the International Conference on Functional Programming on Aug. 20.</p> <p>Vincent W. S. Chan, of the Department of Electrical Engineering and Computer Science, was elected <a href="">2020-21 president of the IEEE Communication Society</a> on Sept. 5.</p> <p>Victor Chernozhukov, of the Institute for Data, Systems, and Society, was <a href="">named a fellow of the Institute of Mathematical Statistics</a> on May 15.</p> <p>Michael Cima, of the Department of Materials Science and Engineering, won the&nbsp;<a href="">W. David Kingery Award</a> from the American Ceramic Society on Oct. 16.</p> <p>James Collins, of the Institute for Medical Engineering and Science, won the <a href="">2020 Max Delbrück Prize in Biological Physics</a> from the American Physical Society on Sept. 26.</p> <p>Areg Danagoulian, of the Department of Nuclear Science and Engineering, won the <a href="">2019 Radiation Science and Technology Award</a> from the American Nuclear Society on Nov. 17.</p> <p>Peter Dedon and Eric Alm, of the Department of Biological Engineering, won the <a href="">NIH Director’s Transformative Research Award</a> on Oct. 1.</p> <p>Esther Duflo, of the Institute for Data, Systems, and Society, won the <a href="">Nobel Prize for economics</a> on Oct. 14.</p> <p>Ruonan Han, of the Department of Electrical Engineering and Computer Science, was <a href="">named the 2020-22 Distinguished Lecturer</a> by the IEEE Microwave Theory and Technique Society on Sept. 11.</p> <p>James M. LeBeau, of the Department of Materials Science and Engineering, won the <a href="">Presidential Early Career Award for Scientists and Engineers</a> on July 2.</p> <p>Nancy Lynch, of the Department of Electrical Engineering and Computer Science, was <a href="">given a doctor honoris causa</a> (honorary doctorate) from the Sorbonne University on Sept. 11.</p> <p>Karthish Manthiram, of the Department of Chemical Engineering, won the <a href="">2019 NSF Faculty Early Career Development (CAREER) Award</a> on Nov. 15.</p> <p>Devavrat Shah, of the Department of Electrical Engineering and Computer Science,&nbsp;won the <a href="">ACM Sigmetrics Test of Time Paper Award</a> on July 22.</p> <p>Suvrit Sra, of the Department of Electrical Engineering and Computer Science, won the <a href=";HistoricalAwards=false">NSF CAREER Award</a> on July 24.</p> <p>Anne White, of the Department of Nuclear Science and Engineering,&nbsp;was named a <a href="">fellow of the American Physical Society</a> on Nov. 17.</p> <p>Cathy Wu, of the Institute for Data, Systems, and Society, won the <a href="">Best PhD Dissertation Award first prize</a> from the IEEE Intelligent Transportation Systems Society on Nov. 12.</p> Photo: Lillie Paquette/School of EngineeringSchool of Engineering, Chemical engineering, Electrical engineering and computer science (EECS), Materials Science and Engineering, Institute for Data, Systems, and Society, Institute for Medical Engineering and Science (IMES), Nuclear science and engineering, Biological engineering, Awards, honors and fellowships, Faculty Five MIT students named 2020 Rhodes Scholars Ali Daher, Claire Halloran, Francisca Vasconcelos, Billy Andersen Woltz, and Megan Yamoah will begin postgraduate studies at Oxford University next fall. Sat, 23 Nov 2019 22:40:19 -0500 Julia Mongo | Distinguished Fellowships <p>Ali Daher, Claire Halloran, Francisca Vasconcelos, Billy Andersen Woltz, and Megan Yamoah have been selected for the 2020 cohort of the prestigious Rhodes Scholarship program. They will begin fully funded postgraduate studies at Oxford University in the U.K. next fall. Each year, Rhodes awards 32 scholarships to U.S. citizens plus additional scholarships reserved for non-U.S. citizens. &nbsp;</p> <p>Halloran, Vasconcelos, Woltz, and Yamoah will join the 2020 American Rhodes Scholar class. Daher was awarded the Rhodes Scholarship for Syria, Jordan, Lebanon and Palestine.</p> <p>The MIT students were supported by MIT’s Distinguished Fellowships team in Career Advising and Professional Development and the MIT Presidential Committee on Distinguished Fellowships. “It has been a gift to work with all of our applicants, and we are especially gratified when the Rhodes committee sees in them the same traits that we value so highly — not just academic excellence, but also thoughtfulness, creativity, initiative, and moral character,” says Professor Tamar Schapiro, who co-chairs the committee along with Professor Will Broadhead.</p> <p><strong>Ali Daher</strong></p> <p>Ali Daher, from Amman, Jordan, is a senior majoring in mechanical engineering with a concentration in biomedical engineering. At Oxford, he will pursue an advanced degree in research science engineering. Daher’s Rhodes Scholarship <a href="">was announced</a> Nov. 15</p> <p><strong>Claire Halloran</strong></p> <p>Hailing from Wauwatosa, Wisconsin, Claire Halloran is a senior majoring in materials science and engineering with minors in energy studies and public policy. At Oxford, Halloran will pursue an MSc in energy systems and a Master of Public Policy. She aspires to become a policy leader who will advocate for legislature that is both technically sound and appropriate for wider social contexts.</p> <p>Halloran is dedicated to creating clean-energy technologies, advocating for strong climate policy, and disseminating knowledge about climate change. Her research has focused on solar energy technologies, including a project on solar-to fuel conversion reactors for concentrated solar systems with the Electrochemical Materials Laboratory in the MIT Department of Materials Science and Engineering, and an independent research project on silicon and perovskite photovoltaics. During a spring study abroad semester at Oxford, Halloran worked on high-energy-density battery design with the Faraday Institution SOLBAT Project, and this past summer she interned at Form Energy, a startup focused on creating low-cost, long-lasting batteries.</p> <p>Halloran has interned with the Environmental Defense Fund and held climate policy fellowships with Our Climate and the Better Future Project. On campus, she founded and directs the MIT Climate Action Team, which works to organize the MIT community in support of policies to mitigate climate change. Halloran also holds an executive position and serves as a peer educator with the MIT Violence Prevention and Response team, facilitating peer conversations about sexual violence and healthy relationships.</p> <p><strong>Francisca Vasconcelos</strong></p> <p>Francisca Vasconcelos is from San Diego, California, and will graduate in 2020 with a double major in electrical engineering and computer science and in physics. Vasconcelos aspires to become an academic, leading a cutting-edge research lab to tackle problems in machine learning and physics, specifically in the domain of quantum computing. She hopes to develop the algorithms, derive the physics, and design the hardware that will drive forward the next revolution in computing, while inspiring and educating the next generation of quantum engineers. At Oxford, she will pursue an MSc in mathematics and foundations of computer science, as well as an MSc in statistical science.</p> <p>Vasconcelos currently conducts research under Professor William Oliver in the Engineering Quantum Systems Group of the Research Lab for Electronics. Her research focuses on extending quantum state tomography for superconducting quantum processors, but she has also worked on a waveguide quantum electrodynamics project and study of radiation induced quasiparticle formation in superconducting qubits. Vasconcelos has done additional research at the MIT Computer Science and Artificial Intelligence Lab NETMIT group, NASA Jet Propulsion Laboratory, MIT Media Lab Camera Culture Group, and Rigetti Computing.</p> <p>Vasconcelos plays for the MIT women's club soccer team and has held leadership roles in the MIT Society of Women Engineers and MIT IEEE Undergraduate Research Technology Conference committee. Vasconcelos is an instructor for the MIT EECS IAP “Intro to Quantum Computing” course and is leading the development of a high school quantum computing curriculum with the nonprofit organization The Coding School.</p> <p><strong>Billy Woltz</strong></p> <p>Growing up on a farm in Logan, Ohio, Billy Woltz had limited options for internet service and STEM education. He arrived at MIT with an interest in physics and modeling complicated systems. He will graduate this spring with a double major in physics and electrical engineering and computer science.</p> <p>At Oxford, Woltz will pursue a second undergraduate degree in philosophy, politics, and economics to acquire skills for making an impact on both the technical and policy aspects of quantum computing. He plans to eventually earn a PhD in physics, conduct research on quantum technologies, and advise legislative bodies on science and technology.</p> <p>Woltz is currently a research assistant in the Engineering Quantum Systems Group in the Research Laboratory of Electronics where he is working on a superconducting qubit platform for quantum information processing. In the Department of Physics, Woltz designed an algorithm for automating data collection from CERN’s particle detectors with the Laboratory for Nuclear Science, and tested the effects of environmental fluctuations on microbial&nbsp;communities&nbsp;with the Physics of Living Systems Group.&nbsp;</p> <p>Woltz founded a summer camp to teach computer science skills to underserved Appalachian and refugee students in rural and urban Ohio communities. A 2018 NEWMAC Runner of the Year, he is captain of the MIT varsity track and field and cross-country teams, and has achieved five All-New England honors. He writes investigative journalism articles for the MIT newspaper&nbsp;<em>The Tech,</em>&nbsp;and likes to read and play guitar in his spare time.</p> <p><strong>Megan Yamoah</strong></p> <p>Megan Yamoah, from Davis, California,&nbsp;is a senior majoring in physics and electrical engineering. The daughter of immigrants from Ghana and Thailand, she seeks to expand on her engineering background to tackle questions involving technology and international development. At Oxford, she will pursue an MPhil in economics to acquire knowledge in development economics and study how innovation can positively impact emerging economies.</p> <p>A Goldwater Scholar with several first-author publications and a patent to her name, Yamoah has focused on the cutting edge of quantum computing. As a high school student, she conducted research in the Goldhaber-Gordon Laboratory at Stanford University. Since her freshman year at MIT, she has been assisting Professor William Oliver in the Engineering Quantum Systems Group in the Research Laboratory of Electronics. She also did a summer research internship in the Q Circuits Group&nbsp;at the&nbsp;École Normale Supérieure de Lyon. This past summer, Yamoah attended workshops for&nbsp;the MIT Regional Acceleration Program (REAP) where she connected&nbsp;with diverse stakeholders from around the world on developing initiatives for spurring innovation. &nbsp;</p> <p>As president of the MIT chapter of the Society of Physics Students, Yamoah worked to develop a physics department statement of values, the first of its kind at MIT. She is an executive board member of Undergraduate Women in Physics and has served multiple roles in the Society of Women Engineers. As a project committee member for MIT Design for America, Yamoah organized&nbsp;workshops for teams creating technology-based solutions for local challenges such as food insecurity.</p> Clockwise from upper left: Megan Yamoah, Billy Woltz, Fran Vasconcelos, Claire Halloran, and Ali Daher Photos: Ian MacLellanStudents, Undergraduate, Awards, honors and fellowships, education, Education, teaching, academics, Graduate, postdoctoral, Student life, Mechanical engineering, DMSE, Electrical Engineering & Computer Science (eecs), Physics, School of Engineering, School of Science Clear, conductive coating could protect advanced solar cells, touch screens New material should be relatively easy to produce at an industrial scale, researchers say. Fri, 22 Nov 2019 13:59:59 -0500 David L. Chandler | MIT News Office <p>MIT researchers have improved on a transparent, conductive coating material, producing a tenfold gain in its electrical conductivity. When incorporated into a type of high-efficiency solar cell, the material increased the cell’s efficiency and stability.</p> <p>The new findings are reported today in the journal <em>Science Advances</em>, in a paper by MIT postdoc Meysam Heydari Gharahcheshmeh, professors Karen Gleason and Jing Kong, and three others.</p> <p>“The goal is to find a material that is electrically conductive as well as transparent,” Gleason explains, which would be “useful in a range of applications, including touch screens and solar cells.” The material most widely used today for such purposes is known as ITO, for indium titanium oxide, but that material is quite brittle and can crack after a period of use, she says.</p> <p>Gleason and her co-researchers improved a flexible version of a transparent, conductive material two years ago and published their findings, but this material still fell well short of matching ITO’s combination of high optical transparency and electrical conductivity. The new, more ordered material, she says, is more than 10 times better than the previous version.</p> <p>The combined transparency and conductivity is measured in units of Siemens per centimeter. ITO ranges from 6,000 to 10,000, and though nobody expected a new material to match those numbers, the goal of the research was to find a material that could reach at least a value of 35. The earlier publication exceeded that by demonstrating a value of 50, and the new material has leapfrogged that result, now clocking in at 3,000; the team is still working on fine-tuning the process to raise that further.</p> <p>The high-performing flexible material, an organic polymer known as PEDOT, is deposited in an ultrathin layer just a few nanometers thick, using a process called oxidative chemical vapor deposition (oCVD). This process results in a layer where the structure of the tiny crystals that form the polymer are all perfectly aligned horizontally, giving the material its high conductivity. Additionally, the oCVD method can decrease the stacking distance between polymer chains within the crystallites, which also enhances electrical conductivity.</p> <p>To demonstrate the material’s potential usefulness, the team incorporated a layer of the highly aligned PEDOT into a perovskite-based solar cell. Such cells are considered a very promising alternative to silicon because of their high efficiency and ease of manufacture, but their lack of durability has been a major drawback. With the new oCVD aligned PEDOT, the perovskite’s efficiency improved and its stability doubled.</p> <p>In the initial tests, the oCVD layer was applied to substrates that were 6 inches in diameter, but the process could be applied directly to a large-scale, roll-to-roll industrial scale manufacturing process, Heydari Gharahcheshmeh says. “It’s now easy to adapt for industrial scale-up,” he says. That’s facilitated by the fact that the coating can be processed at 140 degrees Celsius — a much lower temperature than alternative materials require.</p> <p>The oCVD PEDOT is a mild, single-step process, enabling direct deposition onto plastic substrates, as desired for flexible solar cells and displays. In contrast, the aggressive growth conditions of many other transparent conductive materials require an initial deposition on a different, more robust substrate, followed by complex processes to lift off the layer and transfer it to plastic.</p> <p>Because the material is made by a dry vapor deposition process, the thin layers produced can follow even the finest contours of a surface, coating them all evenly, which could be useful in some applications. For example, it could be coated onto fabric and cover each fiber but still allow the fabric to breathe.</p> <p>The team still needs to demonstrate the system at larger scales and prove its stability over longer periods and under different conditions, so the research is ongoing. But “there’s no technical barrier to moving this forward. It’s really just a matter of who will invest to take it to market,” Gleason says.</p> <p>The research team included MIT postdocs Mohammad Mahdi Tavakoli and Maxwell Robinson, and research affiliate Edward Gleason. The work was supported by Eni S.p.A. under the Eni-MIT Alliance Solar Frontiers Program.</p> Illustration shows the apparatus used to create a thin layer of a transparent, electrically conductive material, to protect solar cells or other devices. The chemicals used to produce the layer, shown in tubes at left, are introduced into a vacuum chamber where they deposit a layer on a substrate material at top of the chamber. Illustration courtesy of the authors, edited by MIT NewsResearch, School of Engineering, Mechanical engineering, Chemical engineering, Polymers, optoelectronics, Solar, Renewable energy, Materials Science and Engineering, Nanoscience and nanotechnology, Electrical Engineering & Computer Science (eecs) Lamborghini and MIT pave the way for the electric supercar of the future MIT-Italy helps build supercharged partnerships on campus and across the globe. Tue, 19 Nov 2019 13:10:01 -0500 MISTI <p>“He was here to dream, and I said 'OK, let's dream together,'” recalls Professor Mircea Dincă of his first encounter with Automobili Lamborghini Head of Development Riccardo Parenti in February 2017. Two years later, the team is celebrating its first major collaborative victory by filing a joint patent.</p> <p>The new patented material was synthesized by Dincă’s lab in the Department of Chemistry, with the support of Automobili Lamborghini’s Concept Development Department, and will serve as the technological base for a new generation of supercapacitors. By increasing the surface area exposed to electric charge in relation to mass and volume, the patent promises to increase energy density by up to 100 percent when compared to existing technology. This is a big leap, even when compared to Lamborghini’s cutting-edge supercapacitors, and, more broadly, a game-changer in high-performance motor sport.</p> <p>A second collaboration, with Professor A. John Hart’s team in the Department of Mechanical Engineering, pursues new design principles for high-performance battery materials that can be integrated into the vehicle structure, and is on schedule to deliver its first prototypes in the next year. Together, these collaborations are key in meeting the performance targets Lamborghini set for its Terzo Millennio car.</p> <p>As Stefano Domenicali, chair and CEO of Automobili Lamborghini, puts it, “The joint research with MIT fully embodies our values and our vocation for anticipating the future: a future in which hybridization is increasingly desirable and inevitably necessary.”</p> <p>Federica Sereni, consul general of Italy in Boston, Massachusetts, comments: "Italian companies, in particular those in the automotive industry, know how to combine passion, tradition, research, and innovation in a way that is unique in the world. Therefore, the match between Lamborghini and MIT is a perfect one, leading to an ideal combination between vision and a level of technological innovation that is among the most advanced in the world".</p> <p>Serenella Sferza, MIT-Italy Program co-director, concurs, praising the MIT-Italy-Lamborghini partnership as a perfect example of how, by acting as a bridge between MIT and Italy’s centers of excellence, the MIT-Italy Program opens avenues for research and innovation that include meaningful student experiences. In this case, after connecting Lamborghini to professors Dincă and Hart, Sferza also recruited mechanical engineering student Patricia Das ’17 and chemical engineering and chemistry student Angela Cai ’19, whose research at Santa Agata Bolognese cemented and advanced the Lamborghini-MIT collaboration.</p> <p>“The Lamborghini-MIT Italy partnership exemplifies the range of MISTI activities and the symbiotic ways in which they feed on each other,” says Sferza. “I initially met Patricia and Angela when they applied to the MIT-Italy Global Teaching Labs program, and, based on their MIT academic background and their strong performance teaching STEM subjects at Italian high schools, later recruited them for the Lamborghini collaboration. Both earned high marks from Lamborghini, and learned a lot from the experience.”</p> <p>“MIT-Italy has given me an invaluable chance to immerse myself in a research topic I am very passionate about in a professional setting with real, global applications,” shares Cai. “I have presented my findings and suggested future research direction to representatives from several departments at my host organization. When I finish my current work assignment, I plan on using the experience and connections gained here to pursue graduate study in this field.”</p> <p>MIT-Italy and Lamborghini, the cornerstone partnership that paved the way for these initiatives, have extended their collaboration and plan to create additional student and research opportunities both on and off campus. In parallel with laboratory work, a campuswide motor sport hackathon is being considered.</p> <p>“This has been such a fruitful partnership for us,” says Sferza. “There are few companies that exemplify the Italian talent for combining beautiful design with high-end technology in such a cool way. It is a joy to connect Lamborghini with MIT’s innovation community.”</p> <p>The faculty, for their part, agree. “This collaboration presented us with the kind of challenges that we love at MIT. We like to understand that the work we’re doing in the lab can contribute to real, new, important technology and also have that work involve good science and engineering,” says Hart. “Our motto is 'mind and hand,' and this gets our minds to focus on a challenge and our hands to do something new and practical in the lab.”</p> <p>“We were dreaming two years ago,” says Dincă. "Now, we really think this could be happening."</p> MIT and Lamborghini recently filed a joint patent for a material that will serve as the technological base for a new generation of supercapacitors. Here, Patricia Das ’17, who interned at Automobili Lamborghini through MIT-Italy, is seen at work at Lamborghini Santa Agata Bolognese Labs. MISTI, Chemistry, Mechanical engineering, Collaboration, Transportation, Automobiles, Materials Science and Engineering, Center for International Studies, School of Engineering, School of Science, School of Humanities Arts and Social Sciences, Patents Materials Research Science and Engineering Center welcomes ultra-high vacuum microscopes Transmission electron microscope and scanning tunneling microscope offer unique capabilities. Thu, 14 Nov 2019 12:20:01 -0500 Denis Paiste | Materials Research Laboratory <p>The Materials Research Laboratory (MRL) welcomed about three dozen guests to celebrate renovations to the Electron Microscopy (EM) Shared Experimental Facility in Building 13, the Vannevar Bush Building, last month.</p> <p>The EM suite, which is part of the National Science Foundation-funded Materials Research Science and Engineering Center (<a dir="ltr" href="" rel="noopener" target="_blank">MRSEC</a>) within MRL, is now home to an ultra-high vacuum transmission electron microscope (TEM) and a scanning tunneling microscope (STM), both of which were donated by IBM to MIT.</p> <p>“Part of this welcome party, from my point of view, is to see which of you would like to get involved with this&nbsp;new equipment,” said&nbsp;<a href="" rel="noopener" target="_blank">Frances M. Ross</a>, the Ellen Swallow Richards Professor in Materials Science and Engineering, who joined&nbsp;the Department of Materials Science and Engineering faculty last year, moving from the Nanoscale Materials Analysis Department at the IBM Thomas J. Watson Research Center.</p> <p>“Both microscopes have unique capabilities. With the TEM, we can grow materials onto a sample while observing the action in the microscope, making a movie that shows how growth takes place. The interior is at ultra-high vacuum so we can prepare a clean sample and be sure that it will stay clean for the duration of the experiment. The STM is also an ultra-high vacuum instrument. It has four tips to measure the sample, capabilities for growth, as well as an integrated ion beam to modify the sample surface.” Ross said&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">her team</a>&nbsp;would be delighted to give tours of the equipment to MIT community members who are interested in learning more.</p> <div class="cms-placeholder-content-video"></div> <p>Looking back on the renovations, Ross says, “You go from a phase where you say, how can this take so long, why must it take months and months and months, and then at other times, you say, wow, how did they possibly finish it so quickly?”</p> <p>Greene Construction completed the EM suite renovations, which included new flooring and lighting, a new entrance, repainting, and an updated meeting area with video presentation capability for meetings or teaching.</p> <p>“It’s a very exciting time for electron microscopy at MIT,” MRL Co-Director Geoffrey S.D. Beach says. “The opportunity is not just to renew this facility, but, as you know, Frances Ross has brought some remarkably unique equipment from IBM and embedded that within this shared experimental facility … We expect great things to happen.”</p> <p>The electron microscopy suite is one of several MRSEC&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Shared Experimental Facilities</a>, which also include materials analysis (surface, thermal, and optical), X-ray diffraction, and nanostructured materials.</p> MIT Professor Frances Ross (center) describes the recently installed ultra-high vacuum scanning tunneling microscope to (background, from left) Geoffrey Beach, Jennifer Meanwell, and William Gilstrap.Photo: Denis Paiste/Materials Research LaboratoryMaterials Research Laboratory, Materials Science and Engineering, Microscopy, Facilities, Physics, Electrical Engineering & Computer Science (eecs), Chemistry Sale of LORD Corporation leads to $1 billion-plus fund for education, research at Cleveland Clinic, Duke, MIT and USC Wed, 13 Nov 2019 11:00:00 -0500 <p><em>The following press release was issued jointly today by MIT, Duke University, University of Southern California, and Cleveland Clinic.</em></p> <p>DURHAM, N.C. -- The sale of LORD Corporation, a century-old, privately-held manufacturing company, has led to the distribution of more than $1 billion to four charitable foundations that support institutions seeking to advance education and research.</p> <p>Cleveland Clinic, Duke University, the Massachusetts Institute of Technology (MIT) and the University of Southern California (USC) will benefit from the distribution of $261 million to each of the four foundations that were the recipients of gifts of stock from Thomas Lord, who led the family-owned company until his death in 1989.</p> <p>Lord’s estate plan created a holding company, Jura Corporation, which owned all of the voting stock and most of the non-voting stock of the LORD Corporation, as well as four foundations which, in turn, owned a significant part of Jura: the Lord Foundation of California, which supports USC; the Lord Foundation of Massachusetts, which supports MIT; the Lord Foundation of North Carolina, which supports Duke; and the Lord Foundation of Ohio, which supports Cleveland Clinic.&nbsp;</p> <p>LORD Corporation, which was founded in Erie, Pa., and is now based in Cary, N.C., grew to sales of more than $1 billion in 2018. It was recently purchased by Parker Hannifin Corporation for $3.675 billion, triggering the distribution of the proceeds to the four foundations.</p> <p>Since their establishment in the early 1980s, the Lord foundations have already provided a total of approximately $200 million to the four institutions for education and research.</p> <p>“When developing his estate plan, Tom Lord identified research institutions that shared his vision of continuous learning and innovation,” said Lt. Gen. Frederick McCorkle, USMC (Ret), president of Jura Corporation. “We are thrilled his legacy of developing new products to solve the world’s problems will continue.”</p> <p>“For 95 years, LORD Corporation transformed innovative ideas into materials and solutions to move every person in the world,” said Ed Auslander, LORD’s former president &amp; CEO. “Consistent with Tom Lord’s deep-rooted values and social responsibility, he leaves a permanent mark on using knowledge and an entrepreneurial spirit to solve technological challenges, making the impossible real.”</p> <p>The distribution of more than $1 billion from the four foundations to their respective institutions, which is expected to be completed following required approvals, is believed to be one of the largest single allocations of its kind.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; _</p> <p><strong>FROM THE RECIPIENTS OF THE LORD FOUNDATION DISTRIBUTIONS</strong></p> <p>“Cleveland Clinic was founded on the ideal that innovation, research and teaching are integral components of patient care,” said <strong>Tom Mihaljevic, M.D., CEO and President of Cleveland Clinic</strong>. “The Lord Foundation’s generous distributions allow us to continue tackling today’s most complex medical challenges, discovering the next breakthroughs and improving lives worldwide.”</p> <p>“The Lord Foundation’s exceptional support for Duke will&nbsp;transform our efforts to address the world’s most intractable problems,” said <strong>Duke President Vincent E. Price</strong>. “From the foundation’s earliest investments in our Pratt School of Engineering to this truly visionary distribution, Tom Lord has left a lasting legacy on Duke’s campus, one that will continue to improve the lives of our students, faculty, staff and those who benefit from their work, for many decades to come.”</p> <p>“Thomas Lord and his successors at LORD Corporation have pioneered a distinctive strategy for giving back to society,” says <strong>MIT President L. Rafael Reif</strong>.&nbsp;“Their generosity to all four institutions is remarkable. And the value of the distribution is magnified because it comes with great flexibility, giving institutions the nimbleness to seize opportunities and address needs that can be hard to cover through traditional philanthropy. We are tremendously grateful.”</p> <p>“We are so grateful for the remarkable vision of Thomas Lord and for the generosity of his enduring support for the research and innovation mission of our university,” said <strong>USC President Carol L. Folt</strong>. “We will honor that legacy by using&nbsp;funding&nbsp;that USC receives from the Lord Foundation of California&nbsp;to drive transformative innovation and scientific advances that will benefit society.”</p> President L. Rafael Reif, Provost, Giving, Materials Science and Engineering, DMSE, Administration, Community, Industry MIT to receive $260 million from Lord Foundation of Massachusetts Longstanding supporter of the Institute allows for flexibility in determining how funds will be used. Wed, 13 Nov 2019 11:00:00 -0500 MIT News Office <p>The Lord Foundation of Massachusetts, one of four existing foundations established by entrepreneur and philanthropist Thomas Lord, has received $260 million, which will be distributed to MIT over time. The funds are part of the proceeds from the sale, finalized Oct. 29, of LORD Corporation, a global technology and manufacturing company headquartered in Cary, North Carolina, to Parker Hannifin Corporation.</p> <p>The distribution to MIT will have a far-reaching impact because of both the magnitude of the funds and the flexibility allowed for their use. Each of the four Lord foundations was established to support a specific institution, and their general mandate is to support the advancement of education, research, science, and technology. MIT, which controls The Lord Foundation of Massachusetts, will be able to invest these dollars around the Institute to advance its mission of educating students and advancing knowledge in service to the nation and the world.</p> <p>“Thomas Lord and his successors at LORD Corporation have pioneered a distinctive strategy for giving back to society,” says MIT President L. Rafael Reif.&nbsp;“Their generosity to all four institutions is remarkable. And the value of the distribution is magnified because it comes with great flexibility, giving institutions the nimbleness to seize opportunities and address needs that can be hard to cover through traditional philanthropy. We are tremendously grateful.”</p> <p>Established in the 1920s, LORD Corporation was a privately held company focusing on noise and vibration control products, electromechanical innovations, automotive and aerospace applications, and chemical products such as specialty adhesives.</p> <p>In 1982, LORD Corporation president Thomas Lord created a holding company for the corporation, now called Jura LLC, and established several foundations that after his death would hold major equity interests. Each foundation benefits a specific university or institution that was selected by Lord and his successor in leading LORD Corporation, Donald Alstadt. Today, four Lord foundations support MIT, Duke University, the University of Southern California, and the Cleveland Clinic.</p> <p>In April 2019, a sale agreement was announced in which Parker Hannifin Corporation would acquire LORD Corporation, triggering the distribution of the proceeds to the four foundations. The assets of each foundation are held in perpetual trust, so their distribution to MIT is defined not as a gift but rather as a “distribution of funds.”</p> <p>The distribution of more than $1 billion from the four foundations to their respective institutions, which is expected to be completed following required approvals, is believed to be one of the largest single allocations of its kind.</p> <p>The Lord Foundation of Massachusetts has already provided MIT with approximately $34.4 million in funds since it began supporting MIT in 1986.</p> <p>“Tom Lord and Don Alstadt were visionary stewards of the company they helmed and of the science and engineering enterprise,” says MIT Provost Martin Schmidt. “We have long been thankful that they selected MIT as one of the beneficiaries of their important legacy. Their foresight and generosity will now enable the Institute to invest even more deeply in its efforts to help solve the world’s great challenges through research, education, and innovation.”</p> <p>Several MIT programs and departments have benefited annually from disbursements from The Lord Foundation. These include the Undergraduate Research Opportunities Program (UROP); student fellowships in the PKG Center; the Thomas Lord Undergraduate Scholarships; and the Thomas Lord Career Development Professorship in the Department of Materials Science and Engineering. It’s expected that the funds from the LORD Corporation sale will be used, in part, to continue the support of these longstanding recipients of annual Lord Foundation funding.</p> <p>The foundation’s board will determine how to distribute the proceeds to MIT.&nbsp; Regarding possible uses for the remainder of the money, Schmidt notes, “The unrestricted nature of these funds gives us the opportunity to use them to invest in pressing needs that are often difficult to support through other means.”</p> <p>“The Academic Council in its annual retreat&nbsp; in June discussed areas where MIT needs to invest over the long term to improve its competitiveness,” Schmidt adds. “Among the areas identified were support for graduate students and graduate research, investments to improve the health and well-being of our community, maintaining the physical plant, and accelerating our work to address climate change. I look forward to discussing with Academic Council how the Lord support might be best deployed toward these needs.”</p> <p>That such investments are now possible is a testament to the vision and planning of Thomas Lord, according to Ed Auslander, LORD’s former president and CEO. “For 95 years, LORD Corporation transformed innovative ideas into materials and solutions to move every person in the world,” he says. “Consistent with Tom Lord’s deep-rooted values and social responsibility, he leaves a permanent mark on using knowledge and an entrepreneurial spirit to solve technological challenges, making the impossible real.”</p> Image: Christopher HartingPresident L. Rafael Reif, Provost, Giving, Materials Science and Engineering, DMSE, Administration, Community, Industry New tools could improve the way cement seals oil wells Techniques for observing concrete as it sets could facilitate the development of new cements. Tue, 12 Nov 2019 11:19:40 -0500 David L. Chandler | MIT News Office <p>A key part of drilling and tapping new oil wells is the use of specialized cements to line the borehole and prevent collapse and leakage of the hole. To keep these cements from hardening too quickly before they penetrate to the deepest levels of the well, they are mixed with chemicals called retarders that slow down the setting process.</p> <p>It’s been hard to study the way these retarders work, however, because the process happens at extreme pressures and temperatures that are hard to reproduce at the surface.</p> <p>Now, researchers at MIT and elsewhere have developed new techniques for observing the setting process in microscopic detail, an advance that they say could lead to the development of new formulations specifically designed for the conditions of a given well location. This could go a long way toward addressing the problems of methane leakage and well collapse that can occur with today’s formulations.</p> <p>Their findings appear in the journal <em>Cement and Concrete Research</em>, in a paper by MIT Professor Oral Buyukozturk, MIT research scientist Kunal Kupwade-Patil, and eight others at the Aramco Research Center in Texas and at Oak Ridge National Laboratory (ORNL) in Tennessee.</p> <p>“There are hundreds of different mixtures” of cement currently in use, says Buyukozturk, who is the George Macomber Professor of Civil and Environmental Engineering at MIT. The new methods developed by this team for observing how these different formulations behave during the setting process “open a new environment for research and&nbsp; innovation” in developing these specialized cements, he says.</p> <p>The cement used to seal the lining of oil wells often has to set hundreds or even thousands of meters below the surface, under extreme conditions and in the presence of various corrosive chemicals. Studies of retarders have typically been done by removing samples of the cured cement from a well for testing in the lab, but such tests do not reveal the details of the sequence of chemical changes taking place during the curing process.</p> <p>The new method uses a unique detector setup at Oak Ridge National Laboratory called the Nanoscale Ordered Materials Diffractometer, or NOMAD, which is used to carry out a process called Neutron Pair Distribution Function analysis, or PDF. This technique can examine in situ the distribution of pairs of atoms in the material that mimic realistic conditions that are encountered in a real oil well at depth.</p> <p>“NOMAD is perfectly suited to study complex structural problems such as understanding hydration in concrete, because of its high flux and the sensitivity of neutrons to light elements such as hydrogen,” says Thomas Proffen of ORNL, a co-author of the paper.</p> <p>The experiments revealed that the primary mechanism at work in widely used retarder materials is the depletion of calcium ions, a key component in the hardening process, within the setting cement. With fewer calcium ions present, the solidifying process is dramatically slowed down. This knowledge should help experimenters to identify different chemical additives that can produce this same effect.</p> <p>When oil wells are drilled, the next step is to insert a steel casing to protect the integrity of the borehole, preventing loose material from collapsing into the well and causing blockages. These casings also prevent the oil and gas, which is under high pressure, from escaping out into the surrounding rock and soil and migrating to the surface, where leakage of methane can play a significant role in contributing to climate change. But there is always a space, which ranges up to a few inches, between the casing and the borehole. This space must be fully filled with cement slurry to prevent leakage and protect the steel lining from exposure to water and corrosive chemicals that could cause it to fail.</p> <p>Methane is a much stronger greenhouse gas than carbon dioxide, so limiting its escape is a crucial step toward limiting the contribution of oil and gas wells to global warming.</p> <p>“The methane, water, and all sorts of different chemicals down there [in the well] create a corrosion problem,” Buyukozturk says. “Also, the well bore circumferential area is next to parts of the Earth’s crust that have instabilities, so material could tumble into the hole and damage the casing.” The way to prevent these instabilities is to pump cement through the casing into the area between the well bore and the casing, which provides “zonal isolation.” The cement then provides a hydraulic seal to keep any water and other fluids away from the casing.</p> <p>But the high temperatures and pressures found at depth present an environment that is “the worst thing you can do to a material,” he says, so it is crucial to understand just how the material and its chemical properties are affected by these harsh surroundings as they do their job of sealing the well.</p> <p>This new method of studying the setting process provides a way “to precisely understand this process, so we can engineer the next generation of retardants,” says Kupwade-Patil, lead author of this paper. “These retardants are very important,” not only for protecting the environment but also for preventing serious economic losses from a damaged or leaking well. “Loss of the seal is serious, so you can’t afford to make a mistake” in the cement sealing process, he says.</p> <p>“After obtaining my PhD, about 30 years ago, my first job was to improve the quality of oil-well cementing,” says Paulo Monteiro, the Roy W. Carlson Distinguished Professor of Civil and Environmental Engineering at the University of California at Berkeley, who was not involved in this work. “At that time there were limited sophisticated characterization techniques, so it is a real pleasure to see X-ray and neutron total scattering methods being applied to study the hydration of oil-well cements in the presence of chemical admixtures.” He adds that these new methods have “the potential to guide the development of tailor-made admixtures that can significantly improve the performance of oil-well cementing.”</p> <p>The research team included Peter J. Boul, Diana Rasner and Carl Thaemlitz from Aramco Service Company and Michelle Everett, Thomas Proffen, Katharine Page, Dong Ma and Daniel Olds from Oak Ridge National Laboratory in Tennessee. The work was supported by Aramco Service Company, of Houston, and the U.S. Department of Energy.&nbsp;</p> Oil and natural gas wells require concrete to seal the area between the well casing and the surrounding borehole, but because of the high temperatures and pressures at depth, it has been hard to study how these specialized cements harden. Now, a new method developed at MIT can help to fill in that missing knowledge.Civil and environmental engineering, Environment, Materials Science and Engineering, Research, School of Engineering, Sustainability, Oil and gas, Emissions Materials Day talks examine the promises and challenges of AI and machine learning The ability to predict and make new materials faster highlights the need for safety, reliability, and accurate data. Tue, 05 Nov 2019 14:10:01 -0500 Denis Paiste | Materials Research Laboratory <p>The promises and challenges of artificial intelligence and machine learning highlighted the Oct. 9 MIT Materials Day Symposium, with presentations on new ways of forming zeolite compounds, faster drug synthesis, advanced optical devices, and more.</p> <p>“Machine learning is having an impact in all areas of materials research,” Materials Research Laboratory Director Carl V. Thompson said.</p> <p>“We’re increasingly able to work in tandem with machines to help us decide what materials to make,” said <a dir="ltr" href="" rel="noopener" target="_blank">Elsa A. Olivetti</a>, the Atlantic Richfield Associate Professor of Energy Studies. Machine learning is also guiding how to make those materials with new insights into synthesis methods, and, in some cases (such as with robotic systems), actually making those materials, she noted.</p> <p>Keynote speaker Brian Storey, director of accelerated materials design and discovery at Toyota Research Institute, spoke about machine learning to&nbsp;advance the switch&nbsp;from the internal combustion engine to electric vehicles, and Professor Ju Li, the Battelle Energy Alliance Professor of Nuclear Science and Engineering and professor of materials science and engineering, spoke about&nbsp;atomic engineering&nbsp;using elastic strain and radiation nudging of atoms.</p> <p><strong>Porous materials</strong></p> <p>Olivetti and&nbsp;<a href="">Rafael Gomez-Bombarelli</a>, the Toyota Assistant Professor in Materials Processing, worked together to apply machine learning to develop a better understanding of porous materials called zeolites, formed from silicon and aluminum oxide, that have a wide range of uses, from cat litter to petroleum refining.</p> <p>“Essentially, the idea is that the pore has the right size to hold organic molecules,” Gomez-Bombarelli said. While only about 250 zeolites of this class are known to engineers, physicists can calculate hundreds of thousands of possible ways these structures can form. “Some of them can be converted into each other,” he said. “So, you could mine one zeolite, put it under pressure, or heat it up, and it becomes a different one that could be more valuable for a specific application.”</p> <p>A traditional method was to interpret these crystalline structures as a combination of building blocks. However, when zeolite transformations were analyzed, more than half the time there were no building blocks in common between the original zeolite before the change and the new zeolite after the change. “Building block theory has some interesting ingredients, but doesn’t quite explain the rules to go from A to B,” Gomez-Bombarelli said.</p> <p><strong>Graph-based approach</strong></p> <p>Gomez-Bombarelli’s new&nbsp;graph-based approach&nbsp;finds that when each zeolite framework structure is represented as a graph, these graphs match before and after in zeolite transformation pairs. “Some classes of transformations only happen between zeolites that have the same graph,” he said.</p> <p>This work evolved from Olivetti’s data mining of 2.5 million materials science journal articles to uncover recipes for making different inorganic materials. The zeolite study examined 70,000 papers. “One of the challenges in learning from the literature is we publish positive examples, we publish data of things that went well,” Olivetti said. In the zeolite community, researchers also publish what doesn’t work. “That’s a valuable dataset for us to learn from,” she said. “What we’ve been able to use this dataset for is to try to predict potential synthesis pathways for making particular types of zeolites.”<br /> <br /> In earlier work with colleagues at the University of Massachusetts, Olivetti developed a system that identified common scientific words and techniques found in sentences across this large library and brought together similar findings. “One important challenge in natural language processing is to draw this linked information across a document,” Olivetti explained. “We are trying to build tools that are able to do that linking,” Olivetti says.</p> <p><strong>AI-assisted chemical synthesis</strong></p> <p><a dir="ltr" href="" rel="noopener" target="_blank">Klavs F. Jensen</a>, the Warren K. Lewis Professor of Chemical Engineering and Professor of Materials Science and Engineering, described a&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">chemical synthesis system</a>&nbsp;that combines artificial intelligence-guided processing steps with a robotically operated modular reaction system.</p> <p>For those unfamiliar with synthesis, Jensen explained that “You have reactants you start with, you have reagents that you have to add, catalysts and so forth to make the reaction go, you have intermediates, and ultimately you end up with your product.”</p> <p>The artificial intelligence system combed 12.5 million reactions, creating a set of rules, or library, from about 160,000 of the most commonly used synthesis recipes, Jensen relates. This machine learning approach suggests processing conditions such as what catalysts, solvents, and reagents to use in the reaction.</p> <p>“You can have the system take whatever information it got from the published literature about conditions and so on and you can use that to form a recipe,” he says. Because there is not enough data yet to inform the system, a chemical expert still needs to step in to specify concentrations, flow rates, and process stack configurations, and to ensure safety before sending the recipe to the robotic system.</p> <p>The researchers&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">demonstrated this system</a>&nbsp;by predicting synthesis plans for 15 drugs or drug-like molecules — the painkiller lidocaine, for example, and several high blood pressure drugs — and then making them with the system. The flow reactor system contrasts with a batch system. “In order to be able to accelerate the reactions, we use typically much more aggressive conditions than are done in batch — high temperatures and higher pressures,” Jensen says.</p> <p>The modular system consists of a processing tower with interchangeable reaction modules and a set of different reagents, which are connected together by the robot for each synthesis. These findings were reported in&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank"><em>Science</em></a>.</p> <p>Former PhD students Connor W. Coley and Dale A. Thomas built the computer-aided synthesis planner and the flow reactor system, respectively, and former postdoc Justin A. M. Lummiss did the chemistry along with a large team of MIT Undergraduate Research Opportunity Program students, PhD students, and postdocs. Jensen also notes contributions from MIT faculty colleagues Regina Barzilay, William H. Green, A. John Hart, Tommi Jaakkola, and Tim Jamison. MIT has filed a patent for the robotic handling of fluid connections. The software suite that suggests and prioritizes possible synthesis routes is open source, and an online version is at the <a href="">ASKCOS website</a>.</p> <p><strong>Robustness in machine learning</strong></p> <p>Deep learning systems perform amazingly well on benchmark tasks such as images and natural language processing applications, said Professor&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Asu Ozdaglar</a>, who heads MIT’s Department of Electrical Engineering and Computer Science. Still, researchers are far from understanding why these deep learning systems work, when they will work, and how they generalize. And when they get things wrong, they can go completely awry.</p> <p>Ozdaglar gave an example of an image with a state-of-the-art classifier that can look at a picture of a cute pig and recognize the image as that of a pig. But, “If you add a little bit of, very little, perturbation, what happens is basically the same classifier thinks that’s an airliner,” Ozdaglar said. “So this is sort of an example where people say machine learning is so powerful, it can make pigs fly,” she said, accompanied by audience laughter. “And this immediately tells us basically we have to go beyond our standard approaches.”</p> <p>A potential solution lies in an optimization formulation known as a Minimax, or MinMax, problem. Another place where MinMax formulation arises is in generative adversarial network, or GAN, training. Using an example of images of real cars and fake images of cars, Ozdaglar explained, “We would like these fake images to be drawn from the same distribution as the training set, and this is achieved using two neural networks competing with each other, a generator network and a discriminator network. The generator network creates from random noise these fake images that the discriminator network tries to pull apart to see whether this is real or fake.”</p> <p>“It’s basically another MinMax problem whereby the generator is trying to minimize the distance between these two distributions, fake and real. And then the discriminator is trying to maximize that,” she said. The MinMax problem approach has become the backbone of robust training of deep learning systems, she noted.</p> <p>Ozdaglar added that EECS faculty are applying machine learning to new areas, including health care, citing the work of&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Regina Barzilay</a>&nbsp;in detecting breast cancer and&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">David Sontag</a>&nbsp;in using electronic medical records for medical diagnosis and treatment.</p> <p>The EECS undergraduate machine learning course (6.036) hosted 800 students last spring, and consistently has 600 or more students enrolled, making it the most popular course at MIT. The new Stephen A. Schwarzman College of Computing provides an opportunity to create a more dynamic and adaptable structure than MIT’s traditional department structure. For example, one idea is to create several cross-departmental teaching groups. “We envision things like courses in the foundations of computing, computational science and engineering, social studies of computing, and have these courses taken by all of our students taught jointly by our faculty across MIT,” she said.</p> <p><strong>Optical advantage</strong></p> <p><a dir="ltr" href="" rel="noopener" target="_blank">Juejun "JJ" Hu</a>, associate professor of materials science and engineering, detailed his research coupling a silicon chip-based spectrometer for detecting infrared light wavelengths to a newly created machine learning algorithm. Ordinary spectrometers, going back to Isaac Newton’s first prism, work by splitting light, which reduces intensity, but Hu’s version collects all of the light at a single detector, which preserves light intensity but then poses the problem of identifying different wavelengths from a single capture.</p> <p>“If you want to solve this trade-off between the (spectral) resolution and the signal-to-noise ratio, what you have to do is resort to a new type of spectroscopy tool called wavelength multiplexing spectrometer,” Hu said. His new&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">spectrometer architecture</a>, which is called digital Fourier transform spectroscopy, incorporates tunable optical switches on a silicon chip. The device works by measuring the intensity of light at different optical switch settings and comparing the results. “What you have is essentially a group of linear equations that gives you some linear combination of the light intensity at different wavelengths in the form of a detector reading,” he said.</p> <p>A prototype device with six switches supports a total of 64 unique optical states, which can provide 64 independent readings. “The advantage of this new device architecture is that the performance doubles every time you add a new switch,” he said. Working with&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Brando Miranda</a>&nbsp;at the Center for Brains Minds and Machines at MIT, he developed a new algorithm,&nbsp;<a dir="ltr" href="" rel="noopener" target="_blank">Elastic D1</a>, that gives a resolution down to 0.2 nanometers and gives an accurate light measurement with only two consecutive measurements.</p> <p>“We believe this kind of unique combination between the hardware of a new spectrometer architecture and the algorithm can enable a wide range of applications ranging from industrial process monitoring to medical imaging,” Hu said. Hu also is applying machine learning in his work on complex optical media such as metasurfaces, which are new optical devices featuring an array of specially designed optical antennas that add a phase delay to the incoming light.</p> <p><strong>Poster session winners</strong></p> <p>Nineteen MIT postdocs and graduate students gave two-minute talks about their research during a poster session preview. At the Materials Day&nbsp;Poster Session&nbsp;immediately following the symposium, award winners were mechanical engineering graduate student Erin Looney, media arts and sciences graduate student Bianca Datta, and materials science and engineering postdoc Michael Chon.</p> <p>The <a href="">Materials Research Laboratory</a> serves interdisciplinary groups of faculty, staff, and students, supported by industry, foundations, and government agencies to carry out fundamental engineering research on materials. Research topics include energy conversion and storage, quantum materials, spintronics, photonics, metals, integrated microsystems, materials sustainability, solid-state ionics, complex oxide electronic properties, biogels, and functional fibers.</p> Eight distinguished researchers spoke at the 2019 Materials Day Symposium. Pictured here (l-r) are MIT professors Carl Thompson, Asu Ozdaglar, Elsa Olivetti, and Ju Li.Image: Denis Paiste/Materials Research LaboratoryMaterials Research Laboratory, Materials Science and Engineering, School of Engineering, Electrical engineering and computer science (EECS), MIT Schwarzman College of Computing, Machine learning, Artificial intelligence, Center for Brains Minds and Machines 3 Questions: How to control biofilms in space MIT and University of Colorado researchers are collaborating on an experiment to be sent to the International Space Station. Fri, 01 Nov 2019 11:00:35 -0400 David L. Chandler | MIT News Office <p><em>Researchers from MIT will be collaborating with colleagues at the University of Colorado at Boulder on <a href="" target="_blank">an experiment</a> scheduled to be sent to the International Space Station (ISS) on Nov. 2. The experiment is looking for ways to address the formation of biofilms on surfaces within the space station. These hard-to-kill communities of bacteria or fungi can cause equipment malfunctions and make astronauts sick. </em>MIT News<em> asked professor of mechanical engineering Kripa Varanasi and doctoral student Samantha McBride to describe the planned experiments and their goals.</em></p> <p><strong>Q: </strong>For starters, tell us about the problem that this research aims to address.</p> <p><strong>Varanasi: </strong>Biofilms grow on surfaces in space stations, which initially was a surprise to me. Why would they grow in space? But it’s an issue that can jeopardize the key equipment — space suits, water recycling units, radiators, navigation windows, and so on — and can also lead to human illness. It therefore needs to be understood and characterized, especially for long-duration space missions.</p> <p>In some of the early space station missions like Mir and Skylab, there were astronauts who were getting sick in space. I don’t know if we can say for sure it’s due to these biofilms, but we do know that there have been equipment failures due to biofilm growth, such as clogged valves.</p> <p>In the past there have been studies that show the biofilms actually grow and accumulate more in space than on Earth, which is kind of surprising. They grow thicker; they have different forms. The goal of this project is to study how biofilms grow in space. Why do they get all these different morphologies? Essentially, it’s the absence of gravity and probably other driving forces, convection for example.</p> <p>We also want to think about remediation approaches. How could you solve this problem? In our current collaboration with <a href="">Luis Zea</a> at UC Boulder, we are looking at biofilm growth on engineered substrates in the presence and absence of gravity. We make different surfaces for these biofilms to grow on, and we apply some of our technologies developed in this lab, including liquid impregnated surfaces [LIS] and superhydrophobic nanotextured surfaces, and we looked at how biofilms grow on them. We found that after a year’s worth of experiments, here on Earth, the LIS surfaces did really well: There was no biofilm growth, compared to many other state of the art substrates.</p> <p><strong>Q:</strong> So what will you be looking for in this new experiment to be flown on the ISS?</p> <p><strong>McBride:</strong> There are signs indicating that bacteria might actually increase their virulence in space, and so astronauts are more likely to get sick. This is interesting because usually when you think of bacteria, you’re thinking of something that’s so small that gravity shouldn’t play that big a role.</p> <p>Professor Cynthia Collin’s group at RPI [Rensselaer Polytechnic Institute] did a previous experiment on the ISS showing that when you have normal gravity, the bacteria are able to move around and form these mushroom-like shapes, versus in microgravity mobile bacteria form this kind of canopy shape of biofilm. So basically, they’re not as constrained any more and they can start to grow outward in this unusual morphology.</p> <p>Our current work is a collaboration with UC Boulder and Luis Zea as the principal investigator. So now instead of just looking at how bacteria respond to microgravity versus gravity on Earth, we’re also looking at how they grow on different engineered substrates. And also, more fundamentally, we can see why bacteria biofilms form the way that they do on Earth, just by taking away that one variable of having the gravity.</p> <p>There are two different experiments, one with bacterial biofilms and one with fungal biofilms. Zea and his group have been growing these organisms in a test media in the presence of those surfaces, and then characterizing them by the biofilm mass, the thickness, morphology, and then the gene expression. These samples will now be sent to the space station to see how they grow there.</p> <p><strong>Q:</strong> So based on the earlier tests, what are you expecting to see when the samples come back to Earth after two months?</p> <p><strong>Varanasi: </strong>What we’ve found so far is that, interestingly, a great deal of biomass grows on superhydrophobic surfaces, which is usually thought to be antifouling. In contrast, on the liquid-impregnated surfaces, the technology behind <a href="">Liquiglide</a>, there was basically no biomass growth. This produced the same result as the negative control, where there were no bacteria.</p> <p>We also did some control tests to confirm that the oil used on the liquid impregnated surfaces is not biocidal. So we’re not just killing the bacteria, they’re actually just not adhering to the substrate, and they’re not growing there.</p> <p><strong>McBride: </strong>For the LIS surfaces, we’ll be looking at whether biofilms form on them or not. I think both results would be really interesting. If biofilms grow on these surfaces in space, but not on the ground, I think that’s going to tell us something very interesting about the behavior of these organisms. And of course, if biofilms don’t form and the surfaces prevent formation like they do on on the ground, then that’s also great, because now we have a mechanism to prevent biofilm formation on some of the equipment in the space station.&nbsp;</p> <p>So we would be happy with either result, but if the LIS does perform as well as it did on the ground, I think it’s going to have a huge impact on future missions in terms of preventing biofilms and not getting people sick.&nbsp;</p> <p>Fundamentally, from a science point of view, we want to understand the growth of these films and understand all of the biomechanical, biophysical, and biochemical mechanisms behind the growth. By adding the surface morphology, texture, and other properties like the liquid-impregnated surfaces, we may see new phenomena in the growth and evolution of these films, and maybe actually come up with a solution to fix the problem.</p> <p><strong>Varanasi:</strong> And then that can lead to designing new equipment or even space suits that have these features. So that’s where I think we would like to learn from this and then propose solutions.</p> NASA’s official mission patch for the upcoming space biofilms experiment, developed at MIT and the University of Colorado, which is scheduled to be sent to the International Space Station.Image courtesy of the researchers.Research, Microbes, Nanoscience and nanotechnology, Mechanical engineering, Surface engineering, NASA, Materials Science and Engineering, 3 Questions, Faculty, Students, Graduate, postdoctoral, School of Science, Space, astronomy and planetary science MADMEC teams address plastic waste problem with materials science Finalists presented an alternative to nondegradable plastics, and an additive to help plastics decompose. Thu, 17 Oct 2019 14:20:57 -0400 Zach Winn | MIT News Office <p>A team with a sustainable alternative to nondegradable plastic earned first place in this year’s MADMEC competition on Oct. 15.</p> <p>The ecoTrio team, made up of three MIT PhD students, took home the $10,000 grand prize in the annual materials science program for its biodgradable blends that imitate various plastics. The second-place prize was awarded to PETTIGREW, which integrated live bacteria into plastic production to improve plastic degradability. RadioStar, which created a low-cost sensor for farmers, came in third.</p> <p>“There seem to be natural themes from year to year,” Michael Tarkanian, a senior lecturer in the Department of Materials Science and Engineering (DMSE) who runs MADMEC, told <em>MIT News</em>. “There were a bunch of plastic postconsumer recycling projects this year, two of which made it to the finals. I think plastics are getting a lot of press lately, with trash piles building up in the oceans and sea animals being injured. Maybe that influenced the students.”</p> <p>The oral and poster presentations were the culmination of team projects that began last spring and included a series of design challenges throughout the summer. Each team received guidance, access to equipment, and up to $1,000 in funding to build and test their prototypes.</p> <p>The teams were judged based on what they accomplished during their journey from idea to prototype. For ecoTrio, that meant creating a material that fit its cost, mechanical, and sustainability goals.</p> <p>“These ideas start from scratch, and the goal is to test their feasibility and develop hardware, so by the time the program is over, students know whether or not they will work,” Tarkanian said.</p> <p><strong>An alternative to nondegradable plastic</strong></p> <p>At the core of ecoTrio’s product are three materials, two of which the company considers proprietary. The first is a polymer that is easily biodegradable but difficult to process and too expensive to compete with plastics on its own. The second material is a biodegradable plastic polymer that’s cheap and makes the blend easier to process at scale using industrial equipment. The third component consists of fine-grained wood particles that the team uses to further lower the cost of the mix and tune the final product for different uses.</p> <p>“Our goal was to create an alternative plastic material that comes exclusively from renewable resources, has the same properties as existing plastics used today, and at the end of its life, biodegrades regardless of where it ends up,” ecoTrio team member Ty Christoff-Tempesta said.</p> <p>Members of the team, which also includes Margaret Lee and Sara Sheffels, say their blend has a similar cost and melting point as traditional plastics, while its strength and flexibility can be adjusted based on the percentage of added wood particles.</p> <p>To demonstrate the range of plastics their product could replace, the team showed off samples including a hard spoon as well as flexible, bag-like materials.</p> <p>“Today, we all recognize single-use plastics as an environmental crisis, but as consumers we come into contact with them all the time, whether it’s packaging for food, cosmetic products, or household products,” Christoff-Tempesta said. “The reason we see them all the time is because they’re so cheap and convenient.”</p> <p>During ecoTrio’s presentation, team members also noted that there is increasing pressure on companies from consumers and the government to use more sustainable packaging.</p> <p><strong>Other promising projects rewarded</strong></p> <p>The second-place team, PETTIGREW, took a different approach to the plastic waste problem. Various methods have been used to quicken the decomposition of plastics after they’re used and collected. Unfortunately, the vast majority of plastics aren’t collected for recycling at all.</p> <p>“Some of these plastics take 1,000 years to degrade on their own, which can have consequences including plastic island formation in the ocean,” said PETTIGREW team member Leonardo Zornberg, a PhD candidate.</p> <p>With these problems in mind, PETTIGREW decided to incorporate decomposition-causing bacteria into plastics as they’re being produced. When the bacteria they selected, <em>Bacillus subtilis</em>, is combined with a sugar filler, it can survive the high temperatures used to shape many plastics.</p> <p>The team also found the addition of the bacteria had only a minimal effect on the strength and flexibility of the plastics in some cases.</p> <p>Zornberg acknowledged the potential for pushback from people hesitant to use plastics with living bacteria inside of them, but he noted the bacterial strain his team selected is frequently used to make probiotics for humans, livestock, and agricultural supplements.</p> <p>Going forward, the team believes genetically engineering the bacteria could further enhance its degradation capabilities, and could even give it other abilities like self-cleaning and antimicrobial defenses.</p> <p>“One of the reasons we chose <em>Bacillus</em> is it’s a model organism,” Zornberg told <em>MIT News</em>. “It’s very well-understood how to genetically engineer and modify its strains, and it’s used in industrial-scale enzyme production, so both of these things suggest it would be suitable if we wanted to modify the bacteria for future applications.”</p> <p>RadioStar broke from this year’s plastic trend by creating a low-cost sensor for small-scale farmers. The sensor makes use of retroreflectors, which are cube-shaped structures that send directional light back toward its source efficiently from a variety of angles.</p> <p>The team’s product consists of small retroreflectors made of gels that can be dispersed across farmland. The biodegradable gels can be made to change colors and optical properties in response to different chemical stimuli. Those changes can then be observed using a directional light emitter and detector, which could be special flashlight held by a farmer or drones equipped with cameras.</p> <p>RadioStar’s prototype was made to change color in response to varying PH levels, but the team believes its sensors could be tuned to monitor a variety of soil conditions.</p> <p>“This is just a proof of concept for how this can be used to test PH, but we can extrapolate this to test a bunch of different parameters,” said RadioStar team member Sara Wilson, an undergraduate in DMSE. “For example, nitrogen, water content, and phosphorous are very important for different types of crop growth.”</p> <p><strong>Learning by doing</strong></p> <p>Overall, Tarkanian thinks this year’s program was a success not just because of the potential of the projects, but also because of the amount of learning-by-doing that led to the final presentations.</p> <p>“The high-level goals [of MADMEC] are to give students the chance to make something tangible and to take the classroom knowledge they’ve been acquiring and put it into practice,” Tarkanian said.</p> <p>Zornberg thinks the MADMEC program, which focuses on earlier-stage venture creation compared to other entrepreneurial programs on campus, helps materials science students think through the process of successful innovation.</p> <p>“Having the opportunity to explore prototyping separated from the business plan is really a good way to engage engineering students in thinking about product design,” Zornberg said.</p> <p>MADMEC is hosted by DMSE and sponsored by Saint Gobain and the Dow Chemical Company.&nbsp;</p> Members of the winning team, ecoTrio, from this year’s MADMEC competition. From left to right are Margaret Lee, Sara Sheffels, and Ty Christoff-Tempesta. Image: James HunterInnovation and Entrepreneurship (I&E), DMSE, School of Engineering, Students, graduate, postdoctoral, Undergraduate, Contests and academic competitions, Sustainability, Recycling, Environment, Pollution, Agriculture Scientists discover fractal patterns in a quantum material The X-ray-focusing lens used in the experiment is based on a design used in lighthouses for centuries. Wed, 16 Oct 2019 16:44:34 -0400 Jennifer Chu | MIT News Office <p>A fractal is any geometric pattern that occurs again and again, at different sizes and scales, within the same object. This “self-similarity” can be seen throughout nature, for example in a snowflake’s edge, a river network, the splitting veins in a fern, and the crackling forks of lightning.</p> <p>Now physicists at MIT and elsewhere have for the first time discovered fractal-like patterns in a quantum material — a material that exhibits strange electronic or magnetic behavior, as a result of quantum, atomic-scale effects.</p> <p>The material in question is neodymium nickel oxide, or NdNiO<sub>3</sub>, a rare earth nickelate that can act, paradoxically, as both an electrical conductor and insulator, depending on its temperature. The material also happens to be magnetic, though the orientation of its magnetism is not uniform throughout the material, but rather resembles a patchwork of “domains.” Each domain represents a region of the material with a particular magnetic orientation, and domains can vary in size and shape throughout the material. The samples used for this study came from the Triscone Lab at the University of Geneva.</p> <p>In their study, the researchers identified a fractal-like pattern within the texture of the material’s magnetic domains. They found that the distribution of domain sizes resembles a downward slope, reflecting a higher number of small domains and a lower number of large domains. If the researchers zoomed in on any part of the total distribution — say, a slice of midsized domains — they observed the same downward-sloping pattern, with a higher number of smaller versus larger domains.&nbsp;</p> <p>As it turns out, this same distribution appears repeatedly throughout the material, no matter the size range, or scale at which it’s observed —&nbsp; a quality that the team recognized as fractal in nature.</p> <p>“The domain pattern was hard to decipher at first, but after analyzing the statistics of domain distribution, we realized it had a fractal behavior,” says Riccardo Comin, assistant professor of physics at MIT. “It was completely unexpected — it was serendipity.”</p> <p>Scientists are exploring neodymium nickel oxide for various applications, including as a possible building block for neuromorphic devices — artificial systems that mimic biological neurons. Just as a neuron can be both active and inactive, depending on the voltage that it receives, NdNiO<sub>3</sub> can be a conductor or an insulator. Comin says an understanding of the material’s nanoscale magnetic and electronic textures is essential to understand and engineer other materials for similar scopes.</p> <p>Comin and his colleagues, including lead author and MIT graduate student Jiarui Li, have published their results today in the journal <em>Nature Communications</em>. The&nbsp;study was conducted by an international team that included researchers at MIT, Brookhaven National Laboratory (BNL), University of Geneva, Purdue University, and University of Zurich.</p> <p><strong>Lighthouses, refocused</strong></p> <p>Comin and Li didn’t intend to find fractals in a quantum material. Instead, the team was studying the effect of temperature on the material’s magnetic domains.</p> <p>“The material is not magnetic at all temperatures,” Comin says. “We wanted to see how these domains pop up and grow once the magnetic phase is reached upon cooling down the material.”</p> <p>To do that, the team had to devise a way to measure the material’s magnetic domains at the nanoscale, since some domains can be as small as several atoms wide, while others span tens of thousands of atoms across.&nbsp;</p> <p>Researchers often use X-rays to probe a material’s magnetic properties. Here, low-energy X-rays, known as soft X-rays, were used to sense the material’s magnetic order and its configuration. Comin and colleagues performed these studies using the National Synchrotron Light Source II at Brookhaven National Laboratory, where a massive, ring-shaped particle accelerator slings electrons around by the billions. The bright beams of soft X-rays produced by this machine are a tool for the most advanced characterization of materials.</p> <p>“But still, this X-ray beam is not nanoscopic,” Comin says. “So we adopted a special solution that allows squeezing this beam down to a very small footprint, so that we could map, point by point, the arrangement of magnetic domains in this material.”</p> <p>In the end, the researchers developed a new X-ray-focusing lens based on a design that’s been used in lighthouses for centuries. Their new X-ray probe is based on the Fresnel lens, a type of composite lens, that is made not from a single, curved slab of glass, but from many pieces of glass, arranged to act like a curved lens. In lighthouses, a Fresnel lens can span several meters across, and it’s used to focus diffuse light produced by a bright lamp into a directional beam that guides ships at sea. Comin’s team fabricated a similar lens, though much smaller, on the order of about 150 microns wide, to focus a soft X-ray beam of several hundred microns in diameter, down to about 70 nanometers wide.</p> <p><strong>“</strong>The beauty of this is, we’re using concepts from geometric optics that have been known for centuries, and have been applied in lighthouses, and we’re just scaling them down by a factor of 10,000 or so,” Comin says.</p> <p><strong>Fractal textures</strong></p> <p>Using their special X-ray-focusing lens, the researchers, working at Brookhaven’s synchrotron light source (beamline CSX), focused incoming soft X-rays beams onto a thin film of neodymium nickel oxide. Then they scanned the much smaller, nanoscopic beam of X-rays across the sample to map the size, shape, and orientation of magnetic domains, point by point. They mapped the sample at different temperatures, confirming that the material became magnetic, or formed magnetic domains, below a certain critical temperature. Above this temperature, the domains disappeared, and the magnetic order was effectively erased.</p> <p>Interestingly, the group found that if they cooled the sample back down to below the critical temperature, the magnetic domains reappeared almost in the same place as before.</p> <p>“So it turns out the system has memory,” Comin says. “The material retains a memory of where the magnetic bits would be. This was also very unexpected. We thought we would see a completely new domain distribution, but we observed the same pattern re-emerging, even after seemingly erasing these magnetic bits altogether.”</p> <p>After mapping the material’s magnetic domains and measuring the size of each domain, the researchers counted the number of domains of a given size and plotted their number as a function of size, using methods developed by the Carlson group at Purdue University. The resulting distribution resembled a downward slope — a pattern that they found, again and again, no matter what range of domain size they focused in on.</p> <p>“We have observed textures of unique richness spanning multiple spatial scales,” Li says. “Most strikingly, we have found that these magnetic patterns have a fractal nature.”</p> <p>Comin says that understanding how a material’s magnetic domains arrange at the nanoscale, and knowing that they exhibit memory, is useful, for instance in designing artificial neurons, and resilient, magnetic data storage devices.</p> <p>“Similar to magnetic disks in spinning hard drives, one can envision storing bits of information in these magnetic domains,” Comin says. “If the material has a sort of memory, you could have a system that’s robust against external perturbations, so even if subjected to heat, the information is not lost.”</p> <p>This research was supported by the National Science Foundation and the Sloan Research Fellowship.</p> The repeating patterns in a snowflake are a classic example of beautiful, geometric fractals. Now MIT scientists have discovered fractal-like patterns in the magnetic configurations of a quantum material for the first time.Image: Chelsea Turner, MITMaterials Science and Engineering, Magnets, Physics, Quantum mechanics, Research, School of Science, Materials Research Laboratory, National Science Foundation (NSF) Cambridge middle school students explore materials science at MIT Materials Research Science and Engineering Center welcomed area students for lessons in glassblowing, making motors, and making ice cream. Fri, 11 Oct 2019 11:20:01 -0400 Susan Rosevear | Materials Research Laboratory <p>Students from Cambridge’s Putnam Avenue Upper School got a taste of materials science, from glassblowing and making simple motors to making liquid nitrogen ice cream, at MIT this summer.</p> <p>The Materials Research Laboratory’s Materials Research Science and Engineering Center (MRSEC) hosted 15 students and their science teacher, Fatima Sammy, for a week of hands-on science and engineering projects.</p> <p>The curriculum also included metal casting, building solar cells, designing objects with fused glass, exploring ultraviolet light, polymer demonstrations, and constructing electric circuits, as well as participating in the “Fish Game,” a mobile-device-enabled game designed to build students’ understanding of complex systems.</p> <p>Classes are taught by MIT staff, technical instructors, graduate students, and undergraduates. Students were on campus from 8:30 a.m. to 2:45 p.m. each day.</p> <p>Basic objectives of the program are to demonstrate to young adolescents that science and engineering is fun, introduce them to the field of materials science, and have them experience science and engineering on a college campus.</p> <p>The 2019 middle school program was the 28th summer the MIT MRSEC has offered a science and engineering program for students from a Cambridge, Massachusetts, middle school. Over the course of those years, the MRSEC has worked with a variety of Cambridge middle schools and reached approximately 400 students.</p> Susan Rosevear (center), education officer for MIT Materials Research Laboratory’s Materials Research Science and Engineering Center, instructs students from the Putnam Avenue Upper School in Cambridge, Massachusetts, how to build a simple direct current (DC) motor.Photo: Denis Paiste/Materials Research LaboratoryMaterials Research Laboratory, STEM education, Community, Cambridge, Boston and region, Materials Science and Engineering, K-12 education, Classes and programs Engineers put Leonardo da Vinci’s bridge design to the test Proposed bridge would have been the world’s longest at the time; new analysis shows it would have worked. Wed, 09 Oct 2019 23:59:59 -0400 David L. Chandler | MIT News Office <p>In 1502 A.D., Sultan Bayezid II sent out the Renaissance equivalent of a government RFP (request for proposals), seeking a design for a bridge to connect Istanbul with its neighbor city Galata. Leonardo da Vinci, already a well-known artist and inventor, came up with a novel bridge design that he described in a letter to the Sultan and sketched in a small drawing in his notebook.</p> <p>He didn’t get the job. But 500 years after his death, the design for what would have been the world’s longest bridge span of its time intrigued researchers at MIT, who wondered how thought-through Leonardo’s concept was and whether it really would have worked.</p> <p>Spoiler alert: Leonardo knew what he was doing.</p> <p>To study the question, recent graduate student Karly Bast MEng ’19, working with professor of architecture and of civil and environmental engineering John Ochsendorf and undergraduate Michelle Xie, tackled the problem by analyzing the available documents, the possible materials and construction methods that were available at the time, and the geological conditions at the proposed site, which was a river estuary called the Golden Horn. Ultimately, the team built a detailed scale model to test the structure’s ability to stand and support weight, and even to withstand settlement of its foundations.</p> <p>The results of the study were presented in Barcelona this week at the conference of the International Association for Shell and Spatial Structures. They will also be featured in a talk at Draper in Cambridge, Massachusetts, later this month and in an episode of the PBS program NOVA, set to air on Nov. 13.</p> <p><strong>A flattened arch</strong></p> <p>In Leonardo’s time, most masonry bridge supports were made in the form of conventional semicircular arches, which would have required 10 or more piers along the span to support such a long bridge. Leonardo’s bridge concept was dramatically different — a flattened arch that would be tall enough to allow a sailboat to pass underneath with its mast in place, as illustrated in his sketch, but that would cross the wide span with a single enormous arch.</p> <p>The bridge would have been about 280 meters long (though Leonardo himself was using a different measurement system, since the metric system was still a few centuries off), making it the longest span in the world at that time, had it been built. “It’s incredibly ambitious,” Bast says. “It was about 10 times longer than typical bridges of that time.”</p> <p>The design also featured an unusual way of stabilizing the span against lateral motions — something that has resulted in the collapse of many bridges over the centuries. To combat that, Leonardo proposed abutments that splayed outward on either side, like a standing subway rider widening her stance to balance in a swaying car.</p> <p>In his notebooks and letter to the Sultan, Leonardo provided no details about the materials that would be used or the method of construction. Bast and the team analyzed the materials available at the time and concluded that the bridge could only have been made of stone, because wood or brick could not have carried the loads of such a long span. And they concluded that, as in classical masonry bridges such as those built by the Romans, the bridge would stand on its own under the force of gravity, without any fasteners or mortar to hold the stone together.</p> <p>To prove that, they had to build a model and demonstrate its stability. That required figuring out how to slice up the complex shape into individual blocks that could be assembled into the final structure. While the full-scale bridge would have been made up of thousands of stone blocks, they decided on a design with 126 blocks for their model, which was built at a scale of 1 to 500 (making it about 32 inches long). Then the individual blocks were made on a 3D printer, taking about six hours per block to produce.</p> <p>“It was time-consuming, but 3D printing allowed us to accurately recreate this very complex geometry,” Bast says.</p> <p><strong>Testing the design’s feasibility</strong></p> <p>This is not the first attempt to reproduce Leonardo’s basic bridge design in physical form. Others, including a pedestrian bridge in Norway, have been inspired by his design, but in that case modern materials — steel and concrete — were used, so that construction provided no information about the practicality of Leonardo’s engineering.</p> <p>“That was not a test to see if his design would work with the technology from his time,” Bast says. But because of the nature of gravity-supported masonry, the faithful scale model, albeit made of a different material, would provide such a test.</p> <p>“It’s all held together by compression only,” she says. “We wanted to really show that the forces are all being transferred within the structure,” which is key to ensuring that the bridge would stand solidly and not topple.</p> <p>As with actual masonry arch bridge construction, the “stones” were supported by a scaffolding structure as they were assembled, and only after they were all in place could the scaffolding be removed to allow the structure to support itself. Then it came time to insert the final piece in the structure, the keystone at the very top of the arch.</p> <p>“When we put it in, we had to squeeze it in. That was the critical moment when we first put the bridge together. I had a lot of doubts” as to whether it would all work, Bast recalls. But “when I put the keystone in, I thought, ‘this is going to work.’ And after that, we took the scaffolding out, and it stood up.”</p> <p>“It’s the power of geometry” that makes it work, she says. “This is a strong concept. It was well thought out.” Score another victory for Leonardo.</p> <p>“Was this sketch just freehanded, something he did in 50 seconds, or is it something he really sat down and thought deeply about? It’s difficult to know” from the available historical material, she says. But proving the effectiveness of the design suggests that Leonardo really did work it out carefully and thoughtfully, she says. “He knew how the physical world works.”</p> <p>He also apparently understood that the region was prone to earthquakes, and incorporated features such as the spread footings that would provide extra stability. To test the structure’s resilience, Bast and Xie built the bridge on two movable platforms and then moved one away from the other to simulate the foundation movements that might result from weak soil. The bridge showed resilience to the horizontal movement, only deforming slightly until being stretched to the point of complete collapse.</p> <p>The design may not have practical implications for modern bridge designers, Bast says, since today’s materials and methods provide many more options for lighter, stronger designs. But the proof of the feasibility of this design sheds more light on what ambitious construction projects might have been possible using only the materials and methods of the early Renaissance. And it once again underscores the brilliance of one of the world’s most prolific inventors.</p> <p>It also demonstrates, Bast says, that “you don’t necessarily need fancy technology to come up with the best ideas.”</p> Recent graduate student Karly Bast shows off the scale model of a bridge designed by Leonardo da Vinci that she and her co-workers used to prove the design’s feasibility. Image: Gretchen ErtlCivil and environmental engineering, Materials Science and Engineering, School of Engineering, Architecture, History, School of Architecture and Planning, Research, 3-D printing A new mathematical approach to understanding zeolites Study of minerals widely used in industrial processes could lead to discovery of new materials for catalysis and filtering. Mon, 07 Oct 2019 11:09:12 -0400 David L. Chandler | MIT News Office <p>Zeolites are a class of natural or manufactured minerals with a sponge-like structure, riddled with tiny pores that make them useful as catalysts or ultrafine filters. But of the millions of zeolite compositions that are theoretically possible, so far only about 248 have ever been discovered or made. Now, research from MIT helps explain why only this small subset has been found, and could help scientists find or produce more zeolites with desired properties.</p> <p>The new findings are being reported this week in the journal <em>Nature Materials</em>, in a paper by MIT graduate students Daniel Schwalbe-Koda and Zach Jensen, and professors Elsa Olivetti and Rafael Gomez-Bombarelli.</p> <p>Previous attempts to figure out why only this small group of possible zeolite compositions has been identified, and to explain why certain types of zeolites can be transformed into specific other types, have failed to come up with a theory that matches the observed data. Now, the MIT team has developed a mathematical approach to describing the different molecular structures. The approach is based on graph theory, which can predict which pairs of zeolite types can be transformed from one to the other.</p> <p>This could be an important step toward finding ways of making zeolites tailored for specific purposes. It could also lead to new pathways for production, since it predicts certain transformations that have not been previously observed. And, it suggests the possibility of producing zeolites that have never been seen before, since some of the predicted pairings would lead to transformations into new types of zeolite structures.</p> <p><strong>Interzeolite tranformations</strong></p> <p>Zeolites are widely used today in applications as varied as catalyzing the “cracking” of petroleum in refineries and absorbing odors as components in cat litterbox filler. Even more applications may become possible if researchers can create new types of zeolites, for example with pore sizes suited to specific types of filtration.</p> <p>All kinds of zeolites are silicate minerals, similar in chemical composition to quartz. In fact, over geological timescales, they will all eventually turn into quartz — a much denser form of the mineral — explains Gomez-Bombarelli, who is the Toyota Assistant Professor in Materials Processing. But in the meantime, they are in a “metastable” form, which can sometimes be transformed into a different metastable form by applying heat or pressure or both. Some of these transformations are well-known and already used to produce desired zeolite varieties from more readily available natural forms.</p> <p>Currently, many zeolites are produced by using chemical compounds known as OSDAs (organic structure-directing agents), which provide a kind of template for their crystallization. But Gomez-Bombarelli says that if instead they can be produced through the transformation of another, readily available form of zeolite, “that’s really exciting. If we don’t need to use OSDAs, then it’s much cheaper [to produce the material].The organic material is pricey. Anything we can make to avoid the organics gets us closer to industrial-scale production.”</p> <p>Traditional chemical modeling of the structure of different zeolite compounds, researchers have found, provides no real clue to finding the pairs of zeolites that can readily transform from one to the other. Compounds that appear structurally similar sometimes are not subject to such transformations, and other pairs that are quite dissimilar turn out to easily interchange. To guide their research, the team used an artificial intelligence system previously developed by the Olivetti group to “read” more than 70,000 research papers on zeolites and select those that specifically identify interzeolite transformations. They then studied those pairs in detail to try to identify common characteristics.</p> <p>What they found was that a topological description based on graph theory, rather than traditional structural modeling, clearly identified the relevant pairings. These graph-based descriptions, based on the number and locations of chemical bonds in the solids rather than their actual physical arrangement, showed that all the known pairings had nearly identical graphs. No such identical graphs were found among pairs that were not subject to transformation.</p> <p>The finding revealed a few previously unknown pairings, some of which turned out to match with preliminary laboratory observations that had not previously been identified as such, thus helping to validate the new model. The system also was successful at predicting which forms of zeolites can intergrow — forming combinations of two types that are interleaved like the fingers on two clasped hands. Such combinations are also commercially useful, for example for sequential catalysis steps using different zeolite materials.</p> <p><strong>Ripe for further research</strong><br /> &nbsp;</p> <p>The new findings might also help explain why many of the theoretically possible zeolite formations don’t seem to actually exist. Since some forms readily transform into others, it may be that some of them transform so quickly that they are never observed on their own. Screening using the graph-based approach may reveal some of these unknown pairings and show why those short-lived forms are not seen.</p> <p>Some zeolites, according to the graph model, “have no hypothetical partners with the same graph, so it doesn’t make sense to try to transform them, but some have thousands of partners” and thus are ripe for further research, Gomez-Bombarelli says.</p> <p>In principle, the new findings could lead to the development of a variety of new catalysts, tuned to the exact chemical reactions they are intended to promote. Gomez-Bombarelli says that almost any desired reaction could hypothetically find an appropriate zeolite material to promote it.</p> <p>“Experimentalists are very excited to find a language to describe their transformations that is predictive,” he says.</p> <p>This work is “a major advancement in the understanding of interzeolite transformations, which has become an increasingly important topic owing to the potential for using these processes to improve the efficiency and economics of commercial zeolite production,” says Jeffrey Rimer, an associate professor of chemical and biomolecular engineering at the University of Houston, who was not involved in this research.</p> <p>Manuel Moliner, a tenured scientist at the Technical University of Valencia, in Spain, who also was not connected to this research, says: “Understanding the pairs involved in particular interzeolite transformations, considering not only known zeolites but also hundreds of hypothetical zeolites that have not ever been synthesized, opens extraordinary practical opportunities to rationalize and direct the synthesis of target zeolites with potential interest as industrial catalysts.”</p> <p>This research was supported, in part, by the National Science Foundation and the Office of Naval Research.</p> Traditional structure-based representations of the many forms of zeolites, some of which are illustrated here, provide little guidance as to how they can convert to other forms, but a new graph-based system does a much better job.Illustrations courtesy of the researchersSchool of Engineering, Materials Science and Engineering, Materials Research Laboratory, Industry, Research, Nanoscience and nanotechnology, Machine learning, Energy storage, Photonics, MIT.nano, Artificial intelligence, DMSE, National Science Foundation (NSF)