Rutgers senior chooses Department of Energy award to study computational physics at Harvard.
2016 Summer Scholar Jennifer Coulter
2016 Summer Scholar Jennifer Coulter will study computational physics at Harvard University after choosing among three prestigious national fellowships that she was offered. At MIT, the graduating Rutgers University senior was a research assistant to Alfredo Alexander-Katz, an associate professor in the Department of Materials Science and Engineering. Photo, Denis Paiste, Materials Processing Center.

Rutgers physics major Jennifer Coulter struck academic gold three times this year, winning some of America’s top science fellowships to study in graduate school.

They are a National Science Foundation Graduate Research Fellowship, a National Defense Science and Engineering Graduate Fellowship and a Department of Energy Computational Science Graduate Fellowship.

Coulter, a senior honored with a prestigious Goldwater scholarship last year, chose the Department of Energy Computational Science Graduate Fellowship. She will begin her studies in the applied physics program at Harvard University this fall and pursue a doctorate in physics.

“It would be very, very cool if I could someday become a physics professor at a university,” said Coulter, 21, who is from Manasquan, New Jersey. “That’s very hard to achieve, so I’m going to give it everything I’ve got. If I can perform well enough to keep doing research, that would make me happiest.”

Arthur D. Casciato, director of Rutgers’ Office of Distinguished Fellowships, said Coulter stands out among her peers. “Considering her Goldwater scholarship last year, Jenny is probably one of the most nationally recognized students in Rutgers’ history,” he said.

A Department of Energy Computational Science Graduate Fellowship provides many benefits. They include:

• $36,000-a-year stipend and full tuition and fees for up to four years at an accredited U.S. university

• $5,000 academic allowance in the first year and $1,000 in each of the following three years to purchase a computer workstation or to cover research and professional development expenses

• 12 weeks at one of 21 Department of Energy (DOE) national laboratories or sites, including access to DOE supercomputers

• A rigorous program of study in a scientific or engineering discipline as well as computer science and applied mathematics

• A program review in the Washington, D.C., area each summer.

“In terms of networking and additional support, this fellowship can’t be beat,” Coulter said. She will take classes and do some research during the first two years of graduate school and focus on research during the last three or four years.

“Essentially, I will be using computational methods to tackle physics problems,” she said. “I will study methods to numerically solve difficult physics problems without analytical solutions. We take a class of very hard physics problems into problems that can be solved using supercomputers.”

Coulter, who has a 3.99 GPA and is in the honors program, lives at Douglass Residential College and is heavily involved in Rutgers research. She has worked with Karin M. Rabe, Board of Governors professor of physics, and Professor Premi Chandra in the Department of Physics and Astronomy in the School of Arts and Sciences. She has also been a research assistant to Dunbar Birnie, a professor in the Department of Materials Science and Engineering in the School of Engineering, and to Sevil Salur, an associate professor in the Department of Physics and Astronomy. Coulter is also a part-time lecturer in the Analytical Physics II Lab in that department.

Last summer, she was a research assistant to Alfredo Alexander-Katz, an associate professor in the Department of Materials Science and Engineering at Massachusetts Institute of Technology, through the Summer Scholars internship program. She modeled how spinning colloidal particles move through a fixed array of obstacles. The Materials Processing Center and the Center for Materials Science and Engineering sponsor the National Science Foundation Research Experience for Undergraduates internships with support from ‪NSF’s Materials Research Science and Engineering Centers program (grant number DMR-1419807). Coulter has also been busy outside of classes and labs. She is president and outreach coordinator in the Rutgers University Society of Physics Students. She’s a mentor and program co-coordinator for the Douglass Project for Rutgers Women in Math, Science and Engineering. She’s the student representative on the Rutgers Department of Physics and Astronomy Undergraduate Studies Committee. And she won an American Physical Society grant to form Rutgers University Women in Physics and Astronomy, a group that she serves as undergraduate chair.

“I never expected to accomplish this much in physics,” said Coulter, who considered majoring in art before she took high school physics. “I just tried to do the best possible physics I could during my undergraduate years and it’s worked out well. I’m going to continue to do the best possible physics and give it everything I’ve got. I think I’m very lucky to have the opportunity to do that.

Article courtesy of Rutgers University.

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Written by Todd B. Bates, Rutgers University
May 1, 2017

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Summer Scholars embrace engineering challenges

Modeling how colloidal particles spin through a fixed array

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MIT researchers team up with leaders from the metals and minerals industry to envision a more sustainable future.
MME Workshop DSC 0424 DCiceri Web
Assistant Professor of Materials Science and Engineering Elsa A. Olivetti [standing, right] shares a summary of a breakout session on disposal and recovery challenges for metals and minerals with participants in the Metals & Minerals for the Environment (MME) initiative’s first public Symposium on May 11 at MIT. Photo, Davide Ciceri.

Metals and minerals form the base of our society, with diverse applications infiltrating all corners of our lives, including agriculture, infrastructure, transportation and information technology. As populations grow, and demand for metals and minerals rises, enhancing the sustainability of the sector is a goal for many companies, communities and policymakers.

To contribute to this, on May 11-12, 2017, MIT launched the Metals & Minerals for the Environment (MME) initiative with its first public Symposium. MIT has long been home to research on myriad aspects of metals and minerals, and the MME Symposium serves to crystallize these efforts around the unique environmental and social challenges the sector faces.

Funded by the MIT Environmental Solutions Initiative, with additional support from the Industrial Liaison Program, the MME Symposium hosted industry professionals involved in sustainability, engineering, R&D, and other related topics. The event featured presentations from MIT faculty and industry experts, as well a glimpse into current research with a tour of MIT laboratories and a student-led poster session.

MME’s Principal Investigator, Assistant Professor of Metallurgy Antoine Allanore, introduced his research around metal extraction by electrolysis, which shows great promise for reducing greenhouse gas emissions and increasing productivity. Co-Principal Investigator T. Alan Hatton, the Ralph Landau Professor of Chemical Engineering, explained his innovations in carbon capture and waste separations, providing another angle for decreasing the industry’s environmental impacts.

Other speakers suggested additional angles for achieving sustainability goals, such as Maurice F. Strong Career Development Professor Matthew Amengual’s work on the impact of mining on local communities, and Professor of Biological Engineering Bevin P. Engelward’s research on the health impacts of metals. Assistant Professor of Materials Science and Engineering Elsa A. Olivetti discussed the potential for higher use of recycled materials and waste byproducts, while John F. Elliott Professor of Materials Chemistry Donald R. Sadoway showed the future of renewable energy battery storage, highly relevant for the remote locations of many mines. Vice President for Open Learning Sanjay Sarma closed out the Symposium, providing a vision of how the Internet of Things can be applied within the metals and minerals sector to monitor safety and increase efficiency.

“This Symposium provided a unique opportunity for MIT researchers to hear directly from the industry what their concerns are, where technologies might be deployed, and what is preventing industry from adopting some sustainability upgrades,” MME Program Manager Suzanne Greene says.

Allanore hopes that the event will culminate in a raised awareness of work at MIT that could be of immediate use to the industry, and of larger innovations under development that could serve as disruptive technologies to modernize the industry.

Learn more about the MME at metalsandminerals.mit.edu.

back to newsletterSuzanne Greene | Department of Materials Science and Engineering
May 22, 2017

MME GroupPic 0430 DCiceri Web
Participants in the Metals & Minerals for the Environment (MME) initiative’s first public Symposium on May 11 and 12 at MIT gathered for a group shot outside Fariborz Maseeh Hall. Photo, Davide Ciceri.

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Mechanical actuators developed by MIT team expand and contract as they let oxygen in and out.
MIT Breathing Films 2 Graphic Web
This diagram illustrates how the thin-film material bends from its normal flat state (center) as oxygen is taken up by its structure (right) or released (left). This behavior enables the film’s shape to be controlled remotely by changing its electric charge. Courtesy of the researchers

Carrying out maintenance tasks inside a nuclear plant puts severe strains on equipment, due to extreme temperatures that are hard for components to endure without degrading. Now, researchers at MIT and elsewhere have come up with a radically new way to make actuators that could be used in such extremely hot environments.

The system relies on oxide materials similar to those used in many of today’s rechargeable batteries, in that ions move in and out of the material during charging and discharging cycles. Whether the ions are lithium ions, in the case of lithium ion batteries, or oxygen ions, in the case of the oxide materials, their reversible motion causes the material to expand and contract.

Such expansion and contraction can be a major issue affecting the usable lifetime of a battery or fuel cell, as the repeated changes in volume can cause cracks to form, potentially leading to short-circuits or degraded performance. But for high-temperature actuators, these volume changes are a desired result rather than an unwelcome side effect.

The findings are described in a report appearing this week in the journal Nature Materials, by Jessica Swallow, an MIT graduate student; Krystyn Van Vliet, the Michael (1949) and Sonja Koerner Professor of Materials Science and Engineering; Harry Tuller, professor of materials science and engineering; and five others.“The most interesting thing about these materials is that they function at temperatures above 500 degrees Celsius,” Swallow explains.

back to newsletterRead more at the MIT News Office.

David L. Chandler | MIT News Office
May 8, 2017 

MIT Breathing Films 1 Swallow Web
"The most interesting thing about these materials is they function at temperatures above 500 degrees Celsius," says MIT graduate student Jessica Swallow, pictured with the equipment used for testing the new materials. Courtesy of the researchers

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Thursday, 18 May 2017 10:45

The tenured engineers of 2017

Twelve appointments in the School of Engineering.
tenured mit engineers 2017 Web
Top row, left to right: Yuriy Roman, Katharina Ribbeck, Ryan Williams, Bradley Olsen, Noelle Selin, and John Hart. Bottom row, left to right: Polina Anikeeva, Cullen Buie, Nuno Loureiro, Timothy Lu, Jessika Trancik, and Xuanhe Zhao.

The School of Engineering has announced that 12 members of its faculty have been granted tenure by MIT.

“This year’s newly tenured faculty in the School of Engineering are remarkable,” said Ian A. Waitz, dean of the School of Engineering. “The scale and breadth of their scholarship and the depth of their commitment to teaching demonstrate how strong we are as a community.”

This year’s newly tenured associate professors are:

Polina Anikeeva PhD ’09, the Class of 1942 Career Development Professor in the Department of Materials Science and Engineering, does research in bioelectronics, specifically the development of materials and devices that enable recording and manipulation of signaling processes within the nervous system.

Read more at the MIT News Office.

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School of Engineering
May 12, 2017

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Platform may be used to explore avenues for quantum computing.
MIT Graphene Semiconductors Web
MIT physicists have found that when a flake of graphene is sandwiched between superconductors, its electronic state changes dramatically, inheriting some of those materials’ superconducting qualities. Pictured is the experimental concept and device schematic.

In normal conductive materials such as silver and copper, electric current flows with varying degrees of resistance, in the form of individual electrons that ping-pong off defects, dissipating energy as they go. Superconductors, by contrast, are so named for their remarkable ability to conduct electricity without resistance, by means of electrons that pair up and move through a material as one, generating no friction.

Now MIT physicists have found that a flake of graphene, when brought in close proximity with two superconducting materials, can inherit some of those materials’ superconducting qualities. As graphene is sandwiched between superconductors, its electronic state changes dramatically, even at its center.

The researchers found that graphene’s electrons, formerly behaving as individual, scattering particles, instead pair up in “Andreev states” — a fundamental electronic configuration that allows a conventional, nonsuperconducting material to carry a “supercurrent,” an electric current that flows without dissipating energy. Their findings, published in Nature Physics, are the first investigation of Andreev states due to superconductivity’s “proximity effect” in a two-dimensional material such as graphene.

Down the road, the researchers’ graphene platform may be used to explore exotic particles, such as Majorana fermions, which are thought to arise from Andreev states and may be key particles for building powerful, error-proof quantum computers.

“There is a huge effort in the condensed physics community to look for exotic quantum electronic states,” says lead author Landry Bretheau, a postdoc in MIT’s Department of Physics. “In particular, new particles called Majorana fermions are predicted to emerge in graphene that is connected to superconducting electrodes and exposed to large magnetic fields. Our experiment is promising, as we are unifying some of these ingredients.”

Landry’s MIT co-authors are postdoc Joel I-Jan Wang, visiting student Riccardo Pisoni, and associate professor of physics Pablo Jarillo-Herrero, along with Kenji Watanabe and Takashi Taniguchi of the National Institute for Materials Science, in Japan.

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Read more at the MIT News Office.

Jennifer Chu | MIT News Office
May 4, 2017

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Desktop Metal thinks its machines will give designers and manufacturers a practical and affordable way to print metal parts.
mj17 3d metal 2 Web
This steel propeller has just been printed. Between the propeller’s blades and the metal support is a thin line of ceramic, which will turn to sand during the sintering process, allowing the finished part to be easily separated from the support.

It’s less than two months before his company’s initial product launch, and CEO Ric Fulop is excitedly showing off rows of stripped-down 3-D printers, several bulky microwave furnaces, and assorted small metal objects on a table for display. Behind a closed door, a team of industrial designers sit around a shared work desk, each facing a large screen. The wall behind them is papered with various possible looks for the startup’s ambitious products: 3-D printers that can fabricate metal parts cheaply and quickly enough to make the technology practical for widespread use in product design and manufacturing.

The company, Desktop Metal, has raised nearly $100 million from leading venture capital firms and the venture units of such companies as General Electric, BMW, and Alphabet. The founders include four prominent MIT professors, including the head of the school’s department of materials science and Emanuel Sachs, who filed one of the original patents on 3-D printing in 1989. Still, despite all the money and expertise, there’s no guarantee the company will succeed in its goal of reinventing how we make metal parts—and thus transforming much of manufacturing.

As Fulop moves about the large, open workspace, his excitement and enthusiasm seem tempered by anxiety. The final commercial printers are not yet ready. Employees are busy tinkering with the machines, and fabricated test objects are scattered about. Progress is being made, but it’s also obvious that the clock is ticking. In a corner near the front door and entrance area, the floor is empty and taped off; soon the space needs to be filled with a mockup of the company’s planned booth for an upcoming trade show.

If it succeeds, Desktop Metal will help solve a daunting challenge that has eluded developers of 3-D printing for more than three decades, severely limiting the technology’s impact. Indeed, despite considerable fanfare and evangelical enthusiasts, 3-D printing has, in many ways, been a disappointment.

Hobbyists and self-proclaimed makers can use relatively inexpensive 3-D printers to make wonderfully complex and ingenious shapes out of plastics. And some designers and engineers have found those machines useful in mocking up potential products, but printing polymer parts has found little use on the production floor in anything but a few specialized products, such as customized hearing aids and dental implants.

Though it is possible to 3-D-print metals, doing so is difficult and pricey. Advanced manufacturing companies such as GE are using very expensive machines with specialized high-power lasers to make a few high-value parts (see “Additive Manufacturing” in our 10 Breakthrough Technologies list of 2013). But printing metals is limited to companies with millions to spend on the equipment, facilities to power the lasers, and highly trained technicians to run it all. And there is still no readily available option for those who want to print various iterations of a metal part during the process of product design and development.

The shortcomings of 3-D printing mean the vision that has long excited its advocates remains elusive. They would like to create a digital design, print out prototypes that they could test and refine, and then use the digital file of the optimized version to create a commercial product or part out of the same material whenever they hit “make” on a 3-D printer. Having an affordable and fast way to print metal parts would be an important step in making this vision a reality.

mj17 3d metal 3 Web
The propeller after processing provides an example of a high-performance part that can be made with 3-D printing. Engineers can use the method to prototype and optimize different designs.

It would give designers more freedom, allowing them to create and test parts and devices with complex shapes that can’t be made easily with any other production method—say, an intricate aluminum lattice or a metal object with internal cavities. It could eventually enable engineers and materials scientists to create parts with new functions and properties by depositing various combinations of materials—for example, printing out a magnetic metal next to a nonmagnetic one. Beyond that, it would redefine the economics of mass production, because the cost of printing something would be the same regardless of how many items were produced. That would change how manufacturers think about the size of factories, the need for backup inventory (why keep many parts in stock if you can simply and quickly print one out?), and the process of tailoring manufacturing to specialized products.

This is why there has been a race to turn 3-D printing into a new way to produce parts. Longtime suppliers of 3-D printers, including Stratasys and 3D Systems, are introducing increasingly advanced machines that are fast enough for manufacturers to use. Last year, HP introduced a line of 3-D printers that the company says will allow manufacturers to prototype and make products with nylon, a widely used thermoplastic. And last fall, GE spent over a billion dollars on a pair of European companies specializing in 3-D-printing of metal parts.

But the real competition for Desktop Metal is probably not from the growing number of companies in 3-D printing. For one thing, the 3-D printers from HP, Stratasys (an investor in Desktop Metal), and 3D Systems mainly use various types of plastics, not the range of metals Fulop’s company wants to use in its printers. And GE’s high-end machines overlap little with Desktop Metal’s market ambitions. Instead, the real competitors for Desktop Metal are more likely to be established metal-processing technologies. Those include automated machining techniques—such as the method used to make the ultra-thin aluminum back casing of iPhones—and a rapidly growing practice called metal injection molding, a common way to mass-produce metal products.

In other words, rather than merely trying to outdo other 3-D printers, Desktop Metal will have the tough task of converting manufacturers away from production methods that are at the heart of their businesses. But the very existence of this large, established market is what makes the prospect so intriguing. Making metal parts, says Fulop, “is a trillion-dollar industry.” And even if 3-D printing wins only a small portion of it, he adds, it could still represent a multibillion-dollar opportunity.

Too hot to print

Look around. Metals are everywhere. But whereas 3-D printing has been widely used in making plastics, the technology’s use in making metal parts “has been narrowly confined,” says Chris Schuh, head of materials science and engineering at MIT and cofounder of Desktop Metal. “Metal processing is more of an art. It’s a very challenging space.”

Making metal objects using 3-D printing is difficult for several reasons. Most obvious is the high temperature required for processing metals. The most common way to print plastics involves heating polymers and squirting the material out the printer nozzle; the plastic then quickly hardens into the desired shape. The process is simple enough to be used in 3-D printers that sell for around $1,000. But building a 3-D printer that directly extrudes metals is not practical, given that aluminum melts at 660 °C, high-carbon steel at 1,370 °C, and titanium at 1,668 °C. Metal parts also have to go through several high-temperature processes to ensure the expected strength and other mechanical properties.

To make a 3-D printer fast enough to be used in manufacturing metal objects, Desktop Metal turned to a technology that dates back to the late 1980s. That’s when a team of MIT engineers led by company cofounder Sachs filed a patent for “three-dimensional printing techniques.” It described a process of putting down a thin layer of metal powder and then using ink-jet printing to deposit a liquid that selectively binds the powder together. The process, which is repeated for hundreds or thousands of layers to define a metal part, can make ones with nearly unlimited geometric complexity. In the most common application of the technology, the binder acts like a glue. However, it can also be used to locally deposit different materials in different locations.

The MIT researchers knew their printing method could be used to make metal and ceramic parts, says Sachs. But they also knew it was too slow to be practical, and the metal powders required for the process were far too expensive at the time. Sachs turned to other research interests, including an effort to improve the manufacturing of photovoltaics (see “Praying for an Energy Miracle”). In the next decades 3-D printing took off and captured the imagination of many product designers. Most famously, a cheap and easy-to-use 3-D printer from MakerBot was introduced in 2009, appealing to many self-styled inventors and tinkerers. But these affordable printers bumped up against the reality that they were limited to using a few cheap plastics. What’s more, though the machines can print complex shapes, the final product often isn’t as good as a plastic part made with conventional technology.

Meanwhile, researchers at industrial manufacturers like GE were busy advancing laser-based technologies invented in the late 1980s for printing metals. These machines use lasers—or, in some cases, high-power electron beams—to draw shapes in a layer of metal powder by melting the material. They repeat the process to build up a three-dimensional object out of the fused powders. The technique is impressive in its capabilities, but it’s slow and expensive. It is worthwhile only for extremely high-value parts that are too complex to make using other methods. Notably, GE’s new jet engine uses a series of sophisticated 3-D-printed fuel nozzles; they are lighter and far more durable because intricate cooling channels have been built into them.

The founders of Desktop Metal decided that to make 3-D metal printing more widely accessible, they would need to sell two different types of machines: a relatively inexpensive “desktop” model suitable for designers and engineers fabricating prototypes, and one that is fast and large enough for manufacturers. Luckily, several innovations have finally made Sachs’s original invention practical for mass production, including the development of very high-speed ink-jet printing for depositing the binder. Successively printing about 1,500 layers, each 50 micrometers thick and deposited in a few seconds, the production-scale printer can build up a 500-cubic-inch part in an hour. That’s about 100 times faster than a laser-based 3-D printer can make metal parts.

For its prototyping machine, Desktop Metal adopted a method from plastic-based 3-D printing. But instead of a softened polymer, it uses metal powders mixed with a flowable polymer binder. The formulation is extruded, using the printed binder to clump the metal powder into the intended shapes.

Key Players in 3-D printing

Stratasys Technology

Technology: One of the original 3-D-printing companies, Stratasys was founded by Scott Crumb, the inventor of fused deposition modeling, the most common way to print plastic parts.

Products: Sells machines that can print a variety of photopolymer and thermoplastic materials.

Carbon

Technology: This Silicon Valley startup has developed a novel photochemical process for fabricating parts out of various plastics, including polyurethane and epoxy.

Products: Introduced a modular system for manufacturers this spring.

HP

Technology: Its line of machines exploits the company’s long history with ink-jet printing through what it calls “multi jet fusion technology.” This uses multiple nozzles for high-speed and high-resolution printing.

Products: Introduced its first 3-D printers last year. The initial machines print nylon, but the company is looking to expand to other materials.

3D Systems

Technology: The first 3-D-printing company, 3D Systems was founded by Chuck Hull, the inventor of stereolithography, which uses light to form parts out of photopolymers. It now offers various types of 3-D printers, including some that print metal parts.

Products: Introduced the latest iteration of stereolithography last year.

However, whether the part is printed with the prototyping machine or the production model, the resulting object—part plastic binder and part metal—lacks the strength of a metal one. So it goes into a specially designed microwave oven for sintering, a process of using heat to make the material more dense, producing a part with the desired properties. In a series of carefully calibrated steps during the sintering process, the polymer is burned off, and then the metal is fused together at a temperature well below its melting point.

The sales pitch

According to the promises of its enthusiasts, 3-D printing will reduce the need for industrial manufacturers and empower local artisan producers (see “The Difference Between Makers and Manufacturers”). The reality is likely to be far different but nonetheless profound. Many sectors of industrial production increasingly use automation and advanced software, and 3-D printing enhances this ongoing move to digital manufacturing. In some ways, it is not unlike an automated machining process that works off a digital file to create a metal part. What’s different about 3-D printing is that it offers ways to make far more complex objects and removes many of the constraints that the production process puts on designers and engineers.

It could also inspire manufacturers to change their logistics and production strategies. For relatively small quantities of goods, 3-D printing could be cheaper, since it eliminates the costs associated with the tooling, casting, and molds required to churn out most metal and plastic objects. The time and money needed to set all that up is one reason why mass production is often required if a manufacturer is going to make money. Without that incentive to commit to mass-scale production, factories could shift production schedules and be more responsive to demand, moving even closer to just-in-time manufacturing. John Hart, a professor of mechanical engineering at MIT and cofounder of Desktop Metal, calls it customized mass production. Rather than having large facilities make a huge number of identical parts that have to be shipped across the world and warehoused, manufacturers might maintain scattered factories that make a diverse set of products, ramping up production as needed. “The implications in a decade or two are probably beyond our imagination,” Hart says. “I don’t really think we know what we will do with these technologies.”

For now, the challenge for Desktop Metal is to get its equipment in the hands of designers and engineers who are responsible for their companies’ next generation of products. This winter Fulop was preparing to showcase the company’s initial product, the prototyping machine, at a trade show in Pittsburgh in early May. (The production 3-D printer is scheduled to be available next year.) His task would be to convince attendees that spending $120,000 on Desktop Metal’s prototyping printer and sintering furnace is essential for the future of their companies.

It is a sales job that Fulop is well suited for. He has started more than a half-dozen companies, beginning with one that imported computer hardware and software that he founded when he was 16 and still living in his native Venezuela. He is probably best known for founding A123 Systems, a battery company that was one of the highest-flying startups in the late 2000s, culminating with a $371 million IPO in 2009. The company was based on a novel lithium-ion technology developed by Yet-Ming Chiang, an MIT professor who is also a cofounder of Desktop Metal. Like their current 3-D-printing startup, A123 hoped to apply materials science expertise to revolutionize a huge market.

It could also inspire manufacturers to change their logistics and production strategies.

Though A123 enjoyed rapid growth and a highly successful IPO, the company declared bankruptcy in 2012 (Fulop left in 2010). Ask Fulop the lesson from A123 and he says simply: “Batteries are a low-margin market.” Indeed, A123 struggled to compete in an increasingly crowded battery business, and it didn’t offer a radical enough performance improvement over established lithium-ion batteries to immediately win over a fledging hybrid-vehicles market (see “A123’s Technology Just Wasn’t Good Enough”).

The challenges faced by Desktop Metal will be very different. A huge market for metal parts already exists. And the startup believes its technology will, at least in the short run, have few direct competitors. Chiang points to the startup’s “really rich” patent portfolio. “It’s not just the materials; it’s the techniques, it’s the [sintering] furnace,” he says. “The harder the technology is, the higher the barrier to entry you build if you’re successful.”

In his office, Chiang has a wooden box containing a half-dozen swords, on loan from the Museum of Fine Arts in Boston, that were made in the 1970s using traditional Japanese techniques. Chiang uses the swords in teaching. The lesson: how the craftsmen used the secrets of metallurgy to turn iron ore into the final product—an ultra-sharp, slightly curved steel sword. Showing off the swords, Chiang points to some of their details, explaining the tricks their makers used, such as the quenching method used to create an extremely hard edge and a softer body. Back at his desk, his attention again on Desktop Metal, he’s equally enthusiastic as he describes the metal objects recently printed by the company and on display at its facilities. What’s exciting is “the idea that you can really make these parts,” Chiang says. “A few hours, and here’s a part that you couldn’t even make before.”

It won’t replace such century-old production techniques such as forging and metal casting, but 3-D printing could create new possibilities in manufacturing – and, just maybe, reimagine the art of metallurgy.

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Article courtesy of the MIT Technology Review.

David Rotman, Editor
MIT Technology Review

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MIT researchers base high-temperature device to produce electricity from industrial waste heat on molten compound’s semiconducting properties.

Thermoelectric Test Cell

Thermoelectric Test Cell MPC Youyang Zhao Web

MIT researchers have demonstrated a liquid thermoelectric device with a molten compound of tin and sulfur that can efficiently convert waste heat to electricity, opening the way to affordably transforming waste heat to energy conversion at high temperatures. Graduate student Youyang Zhao built the thermoelectric test cell based on a concentric cylinder design similar to one used by the late Robert K. Williams, a long-time metal and ceramic division researcher at Oak Ridge National Laboratory in Tennessee, for studying thermal conductivity of molten sulfides. Ilustration, Youyang Zhao

Glass and steel makers produce large amounts of wasted heat energy at high temperatures, but solid-state thermoelectric devices that convert heat to electricity either don’t operate at high enough temperatures or cost so much that their use is limited to special applications such as spacecraft. MIT researchers have developed a liquid thermoelectric device with a molten compound of tin and sulfur that can efficiently convert waste heat to electricity, opening the way to affordably transforming waste heat to power at high temperatures.

Youyang Zhao, a graduate student in Assistant Professor of Metallurgy Antoine Allanore’s research group, built a thermoelectric test cell that operates in a liquid state at temperatures from 950 to 1,074 degrees Celsius [1,742 to 1,965 degrees Fahrenheit]. Commercial thermoelectric devices, based on materials such as solid-state bismuth telluride, operate at about 500 degrees Celsius, and a block of bismuth telluride costs in the neighborhood of 150 times more than tin sulfide per cubic meter [about 35 cubic feet].

Once melted, tin sulfide provides a consistent thermoelectric output over a wide temperature range up to 200 degrees above its melting point of 882 degrees Celsius, says Zhao, first author of an ECS Journal of Solid State Science and Technology paper, “Molten Semiconductors for High Temperature Thermoelectricity,” with Allanore and graduate student Charles Cooper Rinzler. Zhao found no significant performance drop as he cycled the device up to 1,074 degrees Celsius and back down to 950 degrees Celsius, and this over several hours.

“For me, I first heat up the sample to its melting point and then scan the temperature up to 200°C above melting and then scan back while doing multiple measurements during the heating up and the cooling down part. What we found is the property is fairly consistent,” Zhao says.

Materials for large-scale industrial operations

Zhao’s thermoelectric device operates in conditions that are relevant to industrial applications, while the material he used, tin sulfide, is appealing from a cost perspective, Allanore says. Thermoelectric devices work by sandwiching together materials that produce an electric voltage when there is a temperature difference between their hot and cool sides. In reverse, they can be used as cooling devices turning an electric current into a temperature drop. Such devices are used, for example, to heat and cool seats in luxury car models and to power on-board electronics on spacecraft on long journeys (using a nuclear energy source and with specialty devices that can operate at higher temperatures than commercial devices).

The environmental benefits that producing electricity from waste heat yields are unlikely to be a primary motivator for glass and steel makers to adopt this technology, Allanore suggests. These operations have to run their vats or kilns at temperatures of 1,000 degrees Celsius or higher to make their products, and they make their profits off those products. But reaching this high heat is a one-time cost. If thermoelectric management of that heat allows producers to operate hotter, which could increase productivity, or to extend the life of their equipment, then they will be more likely to adapt it, Allanore says. “We already know that in the steady state we have 1,000 degrees Celsius at that location,” he says. And that’s enough to melt the semiconducting materials in a liquid thermoelectric device.

“At the beginning we thought about how do we implement at large scale, on high temperature metallurgical furnaces, materials that could recover waste heat. That was our first idea. But then the second vision of this is to say, what can I do with that electricity? Because you’re not going to deploy that to make electricity, you’re going to deploy that because you have a true benefit to your production,” Allanore explains. Being able to manage heat at very high temperature thanks to electrically active materials like molten compounds is one benefit that is now a possibility.

These findings can have a large impact on metals producers who already handle hundreds of thousands of tons per year of copper sulfide, iron sulfide, and similar materials in their molten state, but who don’t currently take advantage of the materials’ semiconducting properties. “We know how to handle these things at very large scale,” Allanore says.

In 2013, Allanore and John F. Elliott Professor of Materials Chemistry Donald R. Sadoway developed an inexpensive alloy of chromium and iron to serve as the anode in producing steel through molten oxide electrolysis. The process produces metal of high purity and releases oxygen instead of carbon dioxide, which is a major contributor to the greenhouse gas effect. An MIT spinout company, Boston Electrometallurgical Corp., grew out of that work, which has demonstrated molten metal production at the scale of several hundreds pounds per day.

Pairing theory and experiment

The new work on thermoelectric devices under similarly high temperatures provides experimental confirmation of Allanore lab colleague Rinzler’s work explaining the theoretical basis for semiconducting behavior in metallic compounds in their hot, liquid state. Rinzler’s work lays out a predictive framework for quantifying the energy profile [thermodynamics], chemical structure [configuration of atoms] and electronic behavior in certain liquid semiconducting compounds, such as tin sulfide or copper sulfide.

“It’s not a simple matter of just saying what temperature range can you operate under? It’s what can you achieve under practical conditions of operation that matter for the application at hand and at what cost point of material and device,” Rinzler says.

“The beauty of something like this is we that can capture both, we can improve waste heat collection, which we may care about from an energy savings perspective, but industry is encouraged to use it because it actually benefits them in the context that they care about directly as well,” Rinzler says.

Measured on a dollar-per-watt basis, Allanore explains, molten tin sulfide devices could be important to industries that operate at high temperature. “The dollar per watt, when you have large surface area, is dictated by the cost of your material,” he says. Other advantages of the proposed system include the simplicity of handling tin and sulfur, the semiconducting mixture’s relatively high electrical conductivity and relatively low toxicity compared to compounds such as tellurium and thallium or lead and sulfur.

Zhao moved from concept to working device within a year, remarkable progress for scientific research, Allanore notes. “First, it’s Youyang, who is very good, and second it’s the liquid state ... that makes this type of fast demonstration possible,” he says. Zhao earned his B.S. in Materials Science and Engineering from Georgia Institute of Technology in 2013.

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Graduate students Cooper Rinzler and Youyang Zhao and Assistant Professor of Metallurgy Antoine Allanore developed new formulas for predicting which molten compounds will be semiconducting and built a high-temperature thermoelectric device to produce electricity from molten semiconducting compounds that could reuse industrial waste heat. Photo, Denis Paiste, Materials Processing Center.

Self-healing system

“The liquid state is very forgiving of large temperature changes in a way the solid-state is not. If you think about a solid-state material that is going through such a range of temperature, you always have thermal expansion, mechanical problems, corrosion,” he says. These phenomena prevent many solid materials from being reversible in the sense that as the temperature goes up and down, the performance will remain the same. “This is again one of the features of the liquid state. We call it self-healing,” Allanore explains. “As long as you don’t change the chemical composition macroscopically, you just get the same material. From an engineering standpoint and adoption for large-scale application, this is a very important feature.”

“I think people are afraid of it, in a sense, because it seems dangerous to be hot and molten, but once you are molten and know what you are doing, it’s very forgiving,” Allanore says.

For their experimental device, the researchers adapted a concentric cylinder design similar to one used by the late Robert K. Williams, a long-time metal and ceramic division researcher at Oak Ridge National Laboratory in Tennessee, for a 1968 study of thermal conductivity in molten silver sulfide. “They proved convection is a really important factor in liquids,” Zhao says. “And for us, we are designing a device. We are not just talking about the properties of the material. We have to consider the cell geometry and design. When you put a novel material into a device, the overall property might be different from the material itself. So that means it is the overall liquid property, possibly with effect from convection, that dominates the performance of the device.”
Researchers compare different thermoelectric materials by determining their “figure of merit,” which is a measure of each material’s effectiveness at thermoelectric conversion. For many potentially useful compounds at high temperature, Allanore says, the thermoelectric figure of merit has never been investigated, so the new device also provides an experimental framework to evaluate this.

Role of convection

The thermoelectric figure of merit for a device is slightly different than that of the thermoelectric material it uses because of effects from natural convection as well as interference from the device itself. In the paper, Zhao says, “We reported the figure of merit of the device, not necessarily for the material, because we believe there is a contribution, or there is a performance degradation, from natural convection. In that sense, if we could minimize natural convection, the figure of merit for this device could go up.”

“That is the next step for our study,” Zhao says. “Currently I am trying to study what is the effect of natural convection on either [the] Seebeck coefficient [a measure of a material’s strength at converting heat to electricity] or electrical conductivity or thermal conductivity.”

The MIT researchers have filed a provisional patent application for certain aspects of their work.

Allanore hopes the work will broaden understanding of molten compounds. Unlike in solid materials where atoms are relatively fixed, he says, atoms in liquids vary in arrangement on a scale of several micrometers to several millimeters. [Think for example of the difference between the water molecules in a block of frozen ice versus those same molecules in a pot of boiling water.] “In a molten material, you have constant movement, and it’s a complexity that it is not present its solid state and is not described by existing models of the materials science we teach in class,” Allanore says. “We are comfortable that one day we will bridge the two and then it will be a full story that speaks not only about the electronic structure and property, but also what we call physical chemistry, which is viscosity, density, diffusivity – all these phenomena which are essentials to the liquid state.”

The work was supported by MITEI Seed Fund 2013 and the U.S. Air Force Office of Scientific Research (Grant number FA9550-15-1-0046).

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Written by Denis Paiste, Materials Processing Center
May 22, 2017

Related: Faculty Highlight: Antoine Allanore

 

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Materials researcher is working on the magnetic memory of the future.

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“There are many thousands of combinations of materials and interfaces that we can create,” says associate professor Geoffrey Beach. “So with this wealth of material structures, rather than relying on the few materials that nature has given us, we can now design materials and their magnetic properties to exhibit the characteristics that we want.” Photo, M. Scott Brauer

Geoffrey Beach has been tinkering and building things most of his life, including some 50 model rockets that he built and launched while in high school in Oklahoma. But it wasn’t until his undergraduate studies in physics that he zeroed in on the topic that has dominated his research ever since: the study of magnetism and how to control it.

In his work, Beach combines the deep, theoretical understanding of a physicist with an engineer’s passion for building and refining the devices needed to carry out his investigations.

“In high school and college, I was always interested in physics,” says Beach, who is an associate professor in MIT’s Department of Materials Science and Engineering, where he earned tenure in 2015. He received his bachelor’s degree from Caltech, where his interest in magnetism first came into focus.

During those college years studying physics, “everyone there wanted to work on gravity,” he says. “I liked the theoretical aspect, but I’ve always been a very hands-on person. I always liked to build things, and I really like to see how things work.”

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David L. Chandler | MIT News Office
April 24, 2017

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Brittle electrodes handle expansion by going glassy, study shows.

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These images, made by transmission electron microscopy, show the progression of the sodium-olivine electrode material, first in the original starting material in powdered form [a]; after sodium is inserted in different concentrations [b and c]; and after an amorphous, glassy structure forms in between tiny areas of microcrystalline structure [d and e]. Image courtesy of the researchers.

When you charge a battery, or when you use it, it’s not just electricity but also matter that moves around inside. Ions, which are atoms or molecules that have an electric charge, travel from one of the battery’s electrodes to the other, making the electrodes shrink and swell. In fact, it’s been a longstanding mystery why fairly brittle electrode materials don’t crack under the strain of these expansion and contraction cycles.

The answer may have finally been found. A team of researchers at MIT, the University of Southern Denmark, Rice University, and Argonne National Laboratory has determined that the secret is in the electrodes’ molecular structure. While the electrode materials are normally crystalline, with all their atoms neatly arranged in a regular, repetitive array, when they undergo the charging or discharging process, they are transformed into a disordered, glass-like phase that can accommodate the strain of the dimensional changes.

The new findings, which could affect future battery design and even lead to new kinds of actuators, are reported in the journal Nano Letters, in a paper by MIT professor of materials science and engineering Yet-Ming Chiang, graduate students Kai Xiang and Wenting Xing, and eight others.

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David L. Chandler | MIT News Office
April 12, 2017

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Friday, 21 April 2017 17:28

Inside MIT.nano

The MIT Corporation tours the state-of-the-art research facility taking shape in the heart of campus. 

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MIT Professor Krystyn Van Vliet [center] describes how MIT.nano clean rooms will provide a precisely controlled environment. MIT Corporation members Gregory Turner [second-from-left] and Madeleine Gaut  [third-from-left] listen along with Anuradha Agarwal [fourth-from-left], a principal research scientist at the MIT Microphotonics Center. Photo, Jake Belcher

On a recent evening, Cathrin Stickney stood marveling at the stillness of the custom-designed imaging suites in the underground level of MIT.nano — the environmentally quietest space on campus. Laudably ultra-low vibrations, ultra-low electromagnetic interference, and acoustically silent. All in a building that, like most of the rest of MIT, sits on a century-old landfill built on swampland.

“It’s more than difficult to pull that off. It’s architecturally amazing,” Stickney, a successful entrepreneur and former architect, said. Equipped with a neon safety vest and clear safety glasses, Stickney was on site to learn more about a building that embodies one of the largest research investments in MIT history.

The leaders of MIT.nano pulled out all the stops during the first-ever tour of the 214,000 gross-square-foot research facility taking shape in the heart of MIT campus, just steps from the Infinite Corridor. The tightly choreographed public viewing involved safely navigating 60 guests, mostly members of the MIT Corporation, through what is still an active construction site.

Nanoscience and nanotechnology are driving some of the most important innovations today, in health care, energy, computing — almost every field of engineering and science. A facility that allows MIT faculty and students to play a role in these coming changes is of the Institute’s highest priority, says President L. Rafael Reif, who was along for the tour. As he has said: “Even big problems have answers if you have your hands on the right tools.”

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Meg Murphy | School of Engineering
April 7, 2017

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