Observing hydrogen’s effects in metal

Hydrogen, the second-tiniest of all atoms, can penetrate right into the crystal structure of a solid metal.

That’s good news for efforts to store hydrogen fuel safely within the metal itself, but it’s bad news for structures such as the pressure vessels in nuclear plants, where hydrogen uptake eventually makes the vessel’s metal walls more brittle, which can lead to failure. But this embrittlement process is difficult to observe because hydrogen atoms diffuse very fast, even inside the solid metal.

Now, researchers at MIT have figured out a way around that problem, creating a new technique that allows the observation of a metal surface during hydrogen penetration. Their findings are described in a paper appearing today in the International Journal of Hydrogen Energy, by MIT postdoc Jinwoo Kim and Thomas B. King Assistant Professor of Metallurgy C. Cem Tasan.

“It's definitely a cool tool,” says Chris San Marchi, a distinguished member of the technical staff at Sandia National Laboratories, who was not involved in this work. “This new imaging platform has the potential to address some interesting questions about hydrogen transport and trapping in materials, and potentially about the role of crystallography and microstructural constituents on the embrittlement process.”

Hydrogen fuel is considered a potentially major tool for limiting global climate change because it is a high-energy fuel that could eventually be used in cars and planes. However, expensive and heavy high-pressure tanks are needed to contain it. Storing the fuel in the crystal lattice of the metal itself could be cheaper, lighter, and safer — but first the process of how hydrogen enters and leaves the metal must be better understood.

“Hydrogen can diffuse at relatively high rates in the metal, because it’s so small,” Tasan says. “If you take a metal and put it in a hydrogen-rich environment, it will uptake the hydrogen, and this causes hydrogen embrittlement,” he says. That’s because the hydrogen atoms tend to segregate in certain parts of the metal crystal lattice, weakening its chemical bonds.

The new way of observing the embrittlement process as it happens may help to reveal how the embrittlement gets triggered, and it may suggest ways of slowing the process — or of avoiding it by designing alloys that are less vulnerable to embrittlement.

Sandia’s San Marchi says that “this method may play an important role — in coordination with other techniques and simulation — to illuminate the hydrogen-defect interactions that lead to hydrogen embrittlement. With more comprehensive understanding of the mechanisms of hydrogen embrittlement, materials and microstructures can be designed to improve their performance under extreme hydrogen environments.”

The key to the new monitoring process was devising a way of exposing metal surfaces to a hydrogen environment while inside the vacuum chamber of a scanning electron microscope (SEM). Because the SEM requires a vacuum for its operation, hydrogen gas cannot be charged into the metal inside the instrument, and if precharged, the gas diffuses out quickly. Instead, the researchers used a liquid electrolyte that could be contained in a well-sealed chamber, where it is exposed to the underside of a thin sheet of metal. The top of the metal is exposed to the SEM electron beam, which can then probe the structure of the metal and observe the effects of the hydrogen atoms migrating into it.

The hydrogen from the electrolyte “diffuses all the way through to the top” of the metal, where its effects can be seen, Tasan says. The basic design of this contained system could also be used in other kinds of vacuum-based instruments to detect other properties. “It’s a unique setup. As far as we know, the only one in the world that can realize something like this,” he says.

Electron microscope images show the buildup of hydrogen within the crystal structure of a titanium alloy. The images reveal the way hydrogen, depicted in blue, preferentially migrates into the interfaces between crystal grains in the metal. Courtesy of the researchers.

In their initial tests of three different metals — two different kinds of stainless steel and a titanium alloy — the researchers have already made some new findings. For example, they observed the formation and growth process of a nanoscale hydride phase in the most commonly used titanium alloy, at room temperature and in real time.

Devising a leakproof system was crucial to making the process work. The electrolyte needed to charge the metal with hydrogen, “is a bit dangerous for the microscope,” Tasan says. “If the sample fails and the electrolyte is released into the microscope chamber,” it could penetrate far into every nook and cranny of the device and be difficult to clean out. When the time came to carry out their first experiment in the specialized and expensive equipment, he says, “we were excited, but also really nervous. It was unlikely that failure was going to take place, but there’s always that fear.”

Kaneaki Tsuzaki, a distinguished professor of chemical engineering at Kyushu University in Japan, who was not involved in this research, says this “could be a key technique to solve how hydrogen affects dislocation motion. It is very challenging because an acid solution for hydrogen cathodic charging is circulating into an SEM chamber. It is one of the most dangerous measurements for the machine. If the circulation joints leak, a very expensive scanning electron microscope (SEM) would be broken due to the acid solution. A very careful design and a very high-skill setup are necessary for making this measurement equipment.”

Tsuzaki adds that “once it is accomplished, outputs by this method would be super. It has very high spatial resolution due to SEM; it gives in-situ observations under a well-controlled hydrogen atmosphere.” As a result, he says, he believes that Tasan and Kim “will obtain new findings of hydrogen-assisted dislocation motion by this new method, solve the mechanism of hydrogen-induced mechanical degradation, and develop new hydrogen-resistant materials.”

The work was supported by the Exelon Corp.

de MIT News http://bit.ly/2BmBoen

From vision to action

More than 50 students participated in a four-day intensive leadership development program called LeaderShape, during MIT’s Independent Activities Period. 

Over the course of the program, students take a deep-dive in a wide-range of topics and activities such as action planning, team building, group decision-making, and conflict resolution. The program is open to all undergraduate and graduate students and takes place at the Salvation Army Wonderland Conference Center in Sharon, Massachusetts.

Stephon Henry-Rerrie, a senior studying chemical engineering, wanted to take part in the program to break down barriers and have conversations that would develop his leadership skills.

“I expected to be vulnerable with my ideas and to lend myself to learning from other people,” Henry-Rerrie says. “Every conversation I had has impacted me with new knowledge or new perspectives that I’m able to add to my own way of viewing the world.”

Tracy Purinton, director of the MIT Leadership Center, says MIT LeaderShape is also an opportunity for faculty and staff facilitators and students to “explore together what leadership means to them, what leadership means in the context of community, and what leadership means in terms of bringing positive change into the world.”

Each individual creates a plan of action designed to improve the world on a range of topics: apathy, diversity and social justice, education, health care, and technological innovation. From engagement in powerful simulations, activities, and discussions, students learn how to develop their visions in a thoughtful and systematic way that they can execute or carry with them through their lifetime.

In addition to working and providing feedback on their visions in large groups, participants also have the opportunity to interact with renowned MIT faculty and administrators, known as cluster facilitators, in smaller group settings.

This year’s cluster facilitators included Suzy Nelson, vice president and dean of student life; Judy “JJ” Jackson, diversity and inclusion officer; Joseph Granado, associate director of student activities and leadership; Akunna Rosser, assistant director for prehealth advising; and Shawn Ferullo, chief of orthopedics and student health.

The MIT LeaderShape program, which started in 1995, is a partnership between MIT and LeaderShape Inc., a non-profit organization in Champaign, Illinois, that provides materials and the complete curriculum to all campus-based LeaderShape programs nationwide.

Over the years, the LeaderShape program has allowed many students to reflect on the impact they can make as leaders in the world, says MIT Vice President Kirk Kolenbrander.

“Students leave the experience with a plan of action that guides them for many years to come,” Kolenbrander says. “But what they leave with MIT is a deep and lasting commitment to improving our community.”

de MIT News http://bit.ly/2RE7kjJ

New parameters in graduate mentoring

Graduate students facing obstacles in their lives turn to their academic advisors more frequently than any other on-campus resource, according to the most recent MIT Enrolled Graduate Student Survey.

In addition to the expected scholarly advice, feedback on research, and letters of recommendation, many graduate students have expressed appreciation for their advisors’ support of their overall wellbeing, as related in numerous nominations for the Committed to Caring (C2C) Award.

Since its establishment in 2014, the C2C Award has honored over 40 faculty members who are helping to set new standards for holistic graduate mentorship at MIT. Three of the most recent honorees, professors Cullen Buie, Hadley Sikes, and Justin Steil, support their students through collaborative planning, managing mental health, and promoting diversity and inclusivity.

Cullen Buie: Planning together

“I heard a quote once that ‘the best ability is availability’,” says Professor Cullen Buie of the Department of Mechanical Engineering, “and I’m constantly trying to figure out how to be more available for the people I mentor.”

Perhaps what stands out most about Buie’s advising style is his rigorous attention to planning: planning for the next step, planning for changes, and planning together. As one student nominator for the C2C award wrote: “The first thing [Buie] did after hiring me was ask me what I wanted to do with my degree, what were my end goals, what I wanted to do with my life.” This frank yet detailed conversation, the nominator writes, “set the tone for all of our future interactions … his feedback on my all of my work was tailored to my end goal.”

Buie explains that a major focus is to help advisees “think about their future long before those big life decisions have to be made.” This initial sit-down though is not the end of the planning process. After asking students very early in their training about career goals, Buie checks in twice per year to see if anything has changed.

When students are unsure of their goals, Buie encourages them to try new things and sample different career paths. Serving as a teaching assistant for a class or take a summer internship at a national laboratory may provide important exposure to different potential careers, he says.

Part of Buie’s planning program is the informal advising of his students, a mentoring guidepost identified by the C2C program. Being a well-rounded individual is vital, says Buie, for professional and personal reasons. “There is a tendency at a place like MIT to believe that the most important things are your tangible skills and your productivity,” Buie comments, but asserts that productivity may never be seen if one doesn’t communicate the work in a compelling manner. Most importantly, he adds, “years or even a lifetime of hard work can be derailed by ethical or moral failures.”

To keep student careers on track, Buie encourages them “to focus on their softer skills … including their ability to communicate verbally and in writing, and to develop their character.”

Hadley Sikes: Teaching beyond the lab

Professor Hadley D. Sikes of the Department of Chemical Engineering is more than just an academic advisor to her graduate students. She is a role model, a friend, and a sage mentor. One of her former students writes, “[Sikes] completely supported me as a person holistically, and allowed me to become the type of scientist and person that … I really wanted to become.”

Sikes is sensitive to conditions that detract from student wellness. From her decades of lab experience, Sikes identifies “overly long working hours,” “losing a sense of purpose,” and “feelings of isolation” as three of the most common contributors to poor mental health in graduate students. Her commitment to caring has driven her to develop ways fight these issues in her own lab.

“With ambitious projects, it is common to encounter difficulties, but working all the time is not the answer — nor is it sustainable,” Sikes says. To help battle such extended work hours in her lab, Sikes talks openly with her lab members and encourages them to prioritize interests and relationships outside of the lab.

When this sense of purpose fades, which Sikes often sees several years into doctoral research, she reminds her students of the impact of their work in the broader world outside of MIT. The impact of the Sikes Lab in the real-world includes improving diagnostics and therapeutic strategies for diseases like malaria, tuberculosis, and cancer.

Sikes notes that doctoral research can be isolating in many ways, both personally and professionally. To guard against professional isolation, “we form sub-groups of related thesis projects and meet regularly to help one another with troubleshooting.” To fight personal isolation, Sikes supports the social outings and informal gatherings her graduate students organize to enable getting to know one another outside of the lab.

In addition, Sikes does not always wait for her students to come to her but instead may proactively offer guidance, another of the mentoring guideposts identified by the C2C program. “In many cases,” one nominator shared, “I don’t even need to ask her for advice as she herself takes the initiative and educates me about various things.”

Justin Steil: Diversity and inclusivity

Creating an inclusive and supportive work environment for his students and colleagues — another mentoring guidepost identified by the C2C program — is fundamental to Professor Justin Steil’s practice as a professor in the Department of Urban Studies and Planning (DUSP).

“I research urban inequality, racial equity, and inclusive policymaking more broadly,” he remarks. “I strive to create a collaborative learning context in which we recognize that varying perspectives and experiences are essential to effective social science research.” In his view, an inclusive and collaborative approach helps to make research fun and exciting.

His efforts to create an equitable community within DUSP do not go unnoticed by his students. In a nomination letter for the C2C Award, one student wrote, “Steil made our class into a community. This was essential for the hard work ahead, and [it] empowered us to truly work well together.”

Steil’s concern for the wellbeing of his students goes beyond the classroom. Praising Steil, one student writes, “while others might be worried about getting tenure, Justin spends his time strategizing about how to protect our international students in a time of significant threat, about how to create safer environments for all students … and providing endless feedback and support.”

Steil promotes balance and perspective broadly. When asked what advice he would give to incoming graduate students at MIT, Steil offered: “Nurture the love of learning that brought you here. At the same time, keep the inevitable disappointments of research in perspective with the joys of discovery and the richness of life outside of research.”

The sum of Steil’s efforts has led his students to success. In one nominator’s words, “He expects a lot of us — so many readings — and of himself. The bar is high, and we [rise] to it, becoming better versions of ourselves.”

Encouraging mentorship

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.”

C2C invites graduate students from across MIT’s campus to nominate professors whom they believed to be outstanding mentors. Selection criteria for the award include the scope and reach of advisor impact on the experience of graduate students, excellence in scholarship, and demonstrated commitment to diversity and inclusion.

By recognizing the human element of graduate education, C2C seeks to encourage good advising and mentorship across MIT’s campus. 

de MIT News http://bit.ly/2UE7AB1

3 Questions: Ken Urban on theater, science, and tech

Ken Urban, a senior lecturer in MIT’s Music and Theater Arts Program (MTA) is a screenwriter, director, musician, and highly acclaimed playwright, whose work has been performed in New York, London, Boston, and Washington. He joined the faculty in 2017 and now leads MIT’s playwriting program. Recently, he launched the MTA Playwrights Lab, a groundbreaking collaboration between MIT students and professional theater artists.

Q: You began college studying chemical engineering but instead became a world-class playwright. In what ways does your affinity for math and science inform your writing or your approach to theater-making? More broadly, do you see fruitful connections between the sciences, technology, and the arts?

A. In terms of how the engineer in me helps my playwriting, it comes down to a question of structure. The thing I loved about studying math and science was how it helped reveal the hidden structure of the universe, and answered questions about how things functioned. When I write a play, I am telling a story and I need to find the best structure to tell that story. When I was in Catholic grammar school, I loved to diagram sentences. We would take a complex sentence and break it down into the parts of speech, then represent that structure in a compact, orderly diagram. What I loved was how it combined my love of language with my love of problem solving. I do the same thing, in a way, when I write a play. I break down the story into scenes, into beats, trying to figure the best, most exciting way to reveal a character or the plot. That feels to me like the work of an engineer.

The larger connection between theater making, and science and technology is a little trickier. As a playwright invested in psychology, I love the unadorned quality of plays, of actors on a set being in a believable and emotionally-rich scenario. I admire the work of the Wooster Group, Reza Abdoh — I’m helping organize a retrospective of his work here on campus in February — and others in the experimental scene, who use technology as an integral part of their aesthetic. I just don’t tend to create work like that. Plays about science are especially hard. The amount of material you need to cover for a general audience to understand the science itself can make those plays feel exposition-heavy. That’s never a good thing. It might be why great plays on science are few and far between. But that isn’t stopping me from trying. I am currently working on a new play inspired by Henrietta Lacks and the ethical dilemmas regarding her immortal cells, which are used in labs across the globe.

That play will be workshopped here at MIT at our new theater building W97 in March. “The Immortals” is a dangerous comedy that uses the science as a springboard for a larger investigation of ethics. I am looking forward to my students seeing how a new play is developed in rehearsal, and no doubt, they will help the actors, the director, and me understand more about biomedical ethics.

Q: What have you learned as a playwright and dramatic writer that might help individuals and societies better navigate this complex time in history?

A. The best writing advice I ever got was from playwright Erik Ehn. He told me you need to feel the breath of your characters on your neck. I took that to mean you need to know them intimately. They cannot be held at a distance. I got that advice at a crucial moment. I was working on Sense of an Ending, a play about the Rwandan genocide, and I was frustrated because I couldn’t understand the two nuns in my play. I was basing these characters on two actual nuns who were convicted of “crimes against humanity” for their perceived role in a church massacre during the 1994 genocide of the Tutsis by the Hutu majority. But Erik’s advice helped me realize that I couldn’t look at these women from the outside. To make these characters work as dramatic engines, to make the play successful as an evening of theater, I had to understand why Sister Justina and Sister Alice did what they did. To see myself in them. To have empathy or at least understanding why these women did not help.

Understanding others is crucial right now. Remember, of course, that understanding is not the same as forgiving or ignoring conflict. But not to sit in a place of judgment: That is the goal. And that’s what being a playwright has taught me. Not to get too personal, but my father is a climate change denier. It enrages me. But what I have come to understand is that he is motivated by fear. To acknowledge the reality of global climate change is terrifying because it means we have to do something. And it means we are leaving a damaged world to the generations after us. Realizing this facet of my father helped me find ways to challenge him without dismissing him as a person. I ask my writers here at MIT to read an article about a 43-year-old female steelworker who is asked to train the Mexican workers who are replacing her when the American plant is shut down and the company moves. I chose this article because I know this is an experience far removed from my students’ lives, but I want them to do the hard work of finding themselves inside her experience and use that as a springboard for their new play. You cannot write convincingly until you care about people who are different from you.

Q: President Reif has said that the solutions to today’s challenges depend on pairing advanced technical and scientific capabilities with a broad understanding of the world’s political, cultural, and economic realities. What do you view as the main deterrent to such collaborative, multi-disciplinary problem-solving and how can we resolve it?

A. In key ways, knowledge has become more and more bifurcated. We have specialties and the solution to these global problems requires a multi-faceted approach. One of the joys of a career in the arts is that I am constantly being asked to go outside my comfort zone and to explore subject matter that is beyond my expertise. My PhdD is in English literature and my dissertation was focused on nihilism and 1990s British theater. I was trained to know a lot about Nietzsche and Sarah Kane. But what do I know about Henrietta Lacks and biomedical research? The Rwandan genocide? Being gay in Uganda?

Writing plays has helped me gain a broader understanding of our world. I don't know how to solve this vast problem [of siloed research], but I do hope that teaching dramatic writing at MIT helps in some small way. Perhaps, teaching students about the collaborations that foster new writing in the theater, also helps to catalyze new ideas and models for how collaborations might work in their own fields and areas of expertise.

Interview prepared by MIT SHASS Communicaitons
Series Editor: Emily Hiestand
Consulting Editor: Elizabeth Karagianis

de MIT News http://bit.ly/2TA2HZW

Study: Much of the surface ocean will shift in color by end of 21st century

Climate change is causing significant changes to phytoplankton in the world’s oceans, and a new MIT study finds that over the coming decades these changes will affect the ocean’s color, intensifying its blue regions and its green ones. Satellites should detect these changes in hue, providing early warning of wide-scale changes to marine ecosystems.

Writing in Nature Communications, researchers report that they have developed a global model that simulates the growth and interaction of different species of phytoplankton, or algae, and how the mix of species in various locations will change as temperatures rise around the world. The researchers also simulated the way phytoplankton absorb and reflect light, and how the ocean’s color changes as global warming affects the makeup of phytoplankton communities.

The researchers ran the model through the end of the 21st century and found that, by the year 2100, more than 50 percent of the world’s oceans will shift in color, due to climate change.

The study suggests that blue regions, such as the subtropics, will become even more blue, reflecting even less phytoplankton — and life in general — in those waters, compared with today. Some regions that are greener today, such as near the poles, may turn even deeper green, as warmer temperatures brew up larger blooms of more diverse phytoplankton.

“The model suggests the changes won’t appear huge to the naked eye, and the ocean will still look like it has blue regions in the subtropics and greener regions near the equator and poles,” says lead author Stephanie Dutkiewicz, a principal research scientist at MIT’s Department of Earth, Atmospheric, and Planetary Sciences and the Joint Program on the Science and Policy of Global Change. “That basic pattern will still be there. But it’ll be enough different that it will affect the rest of the food web that phytoplankton supports.”

Dutkiewicz’s co-authors include Oliver Jahn of MIT, Anna Hickman of the University of Southhampton, Stephanie Henson of the National Oceanography Centre Southampton, Claudie Beaulieu of the University of California at Santa Cruz, and Erwan Monier, former principal research scientist at the MIT Center for Global Change Science, and currently assistant professor at the University of California at Davis, in the Department of Land, Air and Water Resources.

Chlorophyll count

The ocean’s color depends on how sunlight interacts with whatever is in the water. Water molecules alone absorb almost all sunlight except for the blue part of the spectrum, which is reflected back out. Hence, relatively barren open-ocean regions appear as deep blue from space. If there are any organisms in the ocean, they can absorb and reflect different wavelengths of light, depending on their individual properties.

Phytoplankton, for instance, contain chlorophyll, a pigment which absorbs mostly in the blue portions of sunlight to produce carbon for photosynthesis, and less in the green portions. As a result, more green light is reflected back out of the ocean, giving algae-rich regions a greenish hue.

Since the late 1990s, satellites have taken continuous measurements of the ocean’s color. Scientists have used these measurements to derive the amount of chlorophyll, and by extension, phytoplankton, in a given ocean region. But Dutkiewicz says chlorophyll doesn’t necessarily have reflect the sensitive signal of climate change. Any significant swings in chlorophyll could very well be due to global warming, but they could also be due to “natural variability” — normal, periodic upticks in chlorophyll due to natural, weather-related phenomena.

“An El Niño or La Niña event will throw up a very large change in chlorophyll because it’s changing the amount of nutrients that are coming into the system,” Dutkiewicz says. “Because of these big, natural changes that happen every few years, it’s hard to see if things are changing due to climate change, if you’re just looking at chlorophyll.”

Modeling ocean light

Instead of looking to derived estimates of chlorophyll, the team wondered whether they could see a clear signal of climate change’s effect on phytoplankton by looking at satellite measurements of reflected light alone.

The group tweaked a computer model that it has used in the past to predict phytoplankton changes with rising temperatures and ocean acidification. This model takes information about phytoplankton, such as what they consume and how they grow, and incorporates this information into a physical model that simulates the ocean’s currents and mixing. 

This time around, the researchers added a new element to the model, that has not been included in other ocean modeling techniques: the ability to estimate the specific wavelengths of light that are absorbed and reflected by the ocean, depending on the amount and type of organisms in a given region.

“Sunlight will come into the ocean, and anything that’s in the ocean will absorb it, like chlorophyll,” Dutkiewicz says. “Other things will absorb or scatter it, like something with a hard shell. So it’s a complicated process, how light is reflected back out of the ocean to give it its color.”

When the group compared results of their model to actual measurements of reflected light that satellites had taken in the past, they found the two agreed well enough that the model could be used to predict the ocean’s color as environmental conditions change in the future.

“The nice thing about this model is, we can use it as a laboratory, a place where we can experiment, to see how our planet is going to change,” Dutkiewicz says.

A signal in blues and greens

As the researchers cranked up global temperatures in the model, by up to 3 degrees Celsius by 2100 — what most scientists predict will occur under a business-as-usual scenario of relatively no action to reduce greenhouse gases — they found that wavelengths of light in the blue/green waveband responded the fastest.

What’s more, Dutkiewicz observed that this blue/green waveband showed a very clear signal, or shift, due specifically to climate change, taking place much earlier than what scientists have previously found when they looked to chlorophyll, which they projected would exhibit a climate-driven change by 2055.

“Chlorophyll is changing, but you can’t really see it because of its incredible natural variability,” Dutkiewicz says. “But you can see a significant, climate-related shift in some of these wavebands, in the signal being sent out to the satellites. So that’s where we should be looking in satellite measurements, for a real signal of change.”

According to their model, climate change is already changing the makeup of phytoplankton, and by extension, the color of the oceans. By the end of the century, our blue planet may look visibly altered.

“There will be a noticeable difference in the color of 50 percent of the ocean by the end of the 21st century,” Dutkiewicz says. “It could be potentially quite serious. Different types of phytoplankton absorb light differently, and if climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support. “

This research was supported, in part, by NASA and the Department of Energy.

de MIT News http://bit.ly/2TuPrWp

Study evaluates China’s progress in establishing accounting measures to reinforce its Paris pledge

The latest round of United Nations climate talks in Poland in December sought to get the world on track to meet the 2015 Paris Agreement’s long-term goal of keeping global warming well below two degrees Celsius. Toward that end, negotiators from the agreement’s nearly 200 signatory nations were asked to report on their country or region’s progress toward fulfilling its Paris pledge, or Nationally Determined Contributions (NDC). But just how accurate were those progress reports?

That depends on the integrity of the underlying greenhouse gas emissions data that each country used to assess its performance toward meeting the emissions reduction targets spelled out in its NDC. The measurement, reporting and verification (MRV) of a country’s overall emissions and emissions reductions involves culling and validating emissions data from multiple sources, including firms — industrial, nonprofit, and government entities — in different economic sectors. Building reliable firm-based systems for emissions MRV is no easy task, especially in developing countries where misreporting of environmental data can be significant. But a new MIT-led study in Nature Climate Change identifies challenges and opportunities to achieve that goal.

Co-authored by researchers at MIT, Tsinghua University, and Wuhan University, the study focuses on China, the world’s largest carbon dioxide (CO₂) emitter. China’s climate-change mitigation strategy centers on a national emissions trading system (ETS) whose success depends upon accurate emissions reporting at the firm level.  

Using data obtained from two of China’s pilot regional ETS programs, one in Beijing, a highly developed major city, the other in Hubei, a less developed province, the researchers compared firms’ self-reported CO₂ emissions numbers with those verified by independent third parties. The average discrepancy in these numbers decreased significantly in Beijing, going from 17 percent in 2012 to 4 percent in 2014 and 2015 for approximately 400 firms. In Hubei, which launched its system one year later, the number of discrepancies started lower and showed a statistically-insignificant decrease (from 6 percent in 2014 to 5 percent in 2015).

“We conducted multiple tests to determine if there was any evidence for manipulation or collusion in this process,” says MIT Joint Program Research Scientist Da Zhang, the lead author of the study. “While we observed no evidence of this behavior, we did find that firms increasingly reported emissions correctly over the years, resulting in fewer reporting errors and more agreement with verifiers’ numbers.”

In Beijing, the average numbers of reporting errors per firm decreased from 3.7 to 1.9 from 2012 to 2015, with the greatest drops in errors related to inattention and misunderstanding the rules. This tracks with previous studies indicating a reduction in reporting errors after one or two survey rounds.  

The study emphasized that building effective MRV systems at firms in China and other developing countries takes time, resources and attention to detail. Among its recommendations to increase reporting accuracy and prevent manipulation or collusion is to provide external funding from governments or multilateral entities, at least in early years, to pay the independent verifiers. If firms pay for verification, government back-checks are essential to ensure reporting integrity. The study also maintains that strong law enforcement will be necessary to punish any detected incidents of collusion between verifiers and firms.

“Policy efforts to meet the Paris Agreement require robust monitoring, reporting and verification of greenhouse gas emissions to demonstrate real progress,” says MIT Sloan School of Management Assistant Professor Valerie Karplus, a co-author of the study and faculty affiliate of the Joint Program. “Continuously assessing performance will be important to raising confidence in the effectiveness of nascent market-based systems, especially in countries where prior experience with such systems is limited.”

The research was supported by the National Science Foundation of China and the U.S. Energy Information Agency and a consortium of industrial sponsors and federal grants that fund the work of the MIT Joint Program.

de MIT News http://bit.ly/2UyWld3

MIMIC chest X-ray database to provide researchers access to over 350,000 radiographs

Computer vision, or the method of giving machines the ability to process images in an advanced way, has been given increased attention by researchers in the last several years. It is a broad term meant to encompass all the means through which images can be used to achieve medical aims. Applications range from automatically scanning photos taken on mobile phones to creating 3-D renderings that aid in patient evaluations on to developing algorithmic models for emergency room use in underserved areas.

As access to a greater number of images is apt to provide researchers with a volume of data ideal for developing better and more robust algorithms, a collection of visuals that have been enhanced, or scrubbed of patients' identifying details and then highlighted in critical areas, can have massive potential for researchers and radiologists who rely on photographic data in their work.

Last week, the MIT Laboratory for Computational Physiology, a part of the Institute for Medical Engineering and Science (IMES) led by Professor Roger Mark, launched a preview of their MIMIC-Chest X-Ray Database (MIMIC-CXR), a repository of more than 350,000 detailed chest X-rays gathered over five years from the Beth Israel Deaconess Medical Center in Boston. The project, like the lab’s previous MIMIC-III, which houses critical care patient data from over 40,000 intensive care unit stays, is free and open to academic, clinical, and industrial investigators via the research resource PhysioNet. It represents the largest selection of publicly available chest radiographs to date.

With access to the MIMIC-CXR, funded by Philips Research, registered users and their cohorts can more easily develop algorithms for fourteen of the most common findings from a chest X-ray, including pneumonia, cardiomegaly (enlarged heart), edema (excess fluid), and a punctured lung. By way of linking visual markers to specific diagnoses, machines can readily help clinicians draw more accurate conclusions faster and thus, handle more cases in a shorter amount of time. These algorithms could prove especially beneficial for doctors working in underfunded and understaffed hospitals.

“Rural areas typically have no radiologists,” says Research Scientist Alistair E. W. Johnson, co-developer of the database along with Tom J. Pollard, Nathaniel R. Greenbaum, and Matthew P. Lungren; Seth J. Berkowitz, director of radiology informatics innovation; Chih-ying Deng of Harvard Medical School; and Steven Horng, associate director of emergency medicine informatics at Beth Israel. “If you have a room full of ill patients and no time to consult an expert radiologist, that’s somewhere where a model can help.”

In the future, the lab hopes to link the X-ray archive to the MIMIC-III, thus forming a database that includes both patient ICU data and images. There are currently over 9,000 registered MIMIC-III users accessing critical care data, and the MIMIC-CXR would be a boon for those in critical care medicine looking to supplement clinical data with images.

Another asset of the database lies in its timing. Researchers at the Stanford Machine Learning Group and the Stanford Center for Artificial Intelligence in Medicine and Imaging released a similar dataset in January, collected over 15 years at Stanford Hospital. The MIT Laboratory for Computational Physiology and Stanford University groups collaborated to ensure that both datasets released could be used with minimal legwork for the interested researcher.

“With single center studies, you’re never sure if what you’ve found is true of everyone, or a consequence of the type of patients the hospital sees, or the way it gives its care,” Johnson says. “That’s why multicenter trials are so powerful. By working with Stanford, we’ve essentially empowered researchers around the world to run their own multicenter trials without having to spend the millions of dollars that typically costs.”

As with MIMIC-III, researchers will be able to gain access to MIMIC-CXR by first completing a training course on managing human subjects and then agreeing to cite the dataset in their published work. 

“The next step is free text reports,” says Johnson. “We’re moving more towards having a complete history. When a radiologist is looking at a chest X-ray, they know who the person is and why they’re there. If we want to make radiologists’ lives easier, the models need to know who the person is, too.”

de MIT News http://bit.ly/2MKxoZH