Prototyping a pump for brain treatment

Summer Scholar Alejandro Aponte is interning in the lab of Michael J. Cima, the David H. Koch Professor of Engineering at MIT, where he is working on the design of a pump to deliver drugs to the brain.

A mechanical engineering major at the University of Puerto Rico at Mayaguez, Aponte has worked before developing different types of instrumentation, but this is his first time working with research related to human biology. The pump prototype is attached to a needle through which medicine can flow for drug delivery.

Aponte has been focusing on keeping different aspects of the pump as static as possible. MIT postdoc Ritu Raman is guiding Aponte through the seven-week Summer Scholar program, which is sponsored by the Materials Processing Center and the Center for Materials Science and Engineering. 

“That will be really important for when we want to make these smaller and implantable, because not only do we not want movement of the needle, but we also don't want moving of this central actuation portion,” Raman explains.

Aponte was working to move from a modular version made up of separate components — such as the electrical dock and the tubing dock — to an integrated design. Doing so would allow easier measurement of initial pressure, and also prevent bubbles from forming.

“That's actually very important for when we're building prototypes,” Raman says. “We want to take apart every little piece and think about how can we make this part better and that better, and then at the end, we can put it all together.”

Aponte says the objective is to get the setup to be as small as possible. "This is very important because the type of work that we are doing requires the pump to be implantable, so that's our main target here,” he says.

Raman says the Cima lab is working on a range of different types of implants and platforms for diagnosing and treating brain disorders, specifically mood disorders like anxiety and depression that affect many people in the United States and around the world.

“The critical part of this platform is we have these probes that go into very specific neural circuits inside the brain and we want to infuse drugs to those circuits,” Raman says.

Aponte brings his prior experience with instrumentation development to the project.

“I was able to see the overview of the project quick and be comfortable with it,” he says. “And the cherry on top is that it is related to neural science, which has been a topic that I've been really dying to learn. I'm very excited to know that my work might help others' lifestyles be better in the future.”

Aponte’s internship is supported in part by the National Science Foundation’s Materials Research Science and Engineering Centers program.

Participants in the Summer Scholars program, which is also known as the Research Experience for Undergraduates, will present their results at a poster session on Aug. 3. The program runs from June 15 to Aug. 5 on the MIT campus.

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Hybrid drones carry heavier payloads for greater distances

MIT alumnus Long Phan SM ’99, PhD ’12 is a technology innovator and entrepreneur with several engineering “firsts” under his belt.

In the mid-1990s, Phan helped build the Draper Small Autonomous Aerial Vehicle, the world’s first fully autonomous helicopter. While working on Wall Street in the early 2000s, he became an early pioneer of the high-frequency trading system, which consists of powerful computers that rapidly complete tons of trading transactions.

As co-founder, CEO, and chief technology officer of Top Flight Technologies, Phan is now one of the first entrepreneurs to commercialize hybrid gas-to-electric drones. The drones offer an order-of-magnitude increase in range, payload size, and power over battery-powered counterparts.

Coming to market this fall, the hybrid drones could help make drone package-delivery a reality, and enhance capabilities for crop imaging, military surveillance, emergency response, and remote infrastructure inspection, among other applications. As the startup continues to develop hybrid drone power sources, the technology could also pave the way for human flight.

“The key is having an abundance of power and total energy. That’s what petrol and  gasoline gives you,” Phan says. “Using a high-energy-density energy source like gasoline, and converting it to electric power, and doing it efficiently, gives you the equivalent of a ‘super battery.’”

Many drones run on batteries, flying for 15 to 30 minutes between charges, with maximum payloads of 5 pounds. Top Flight’s drone can fly for more than 2.5 hours ­— enabling ranges of up to 100 miles — while carrying up to 20 pounds.

The drone can be customized for any number of industrial-strength applications. The engine weighs about 17 pounds and can generate up to 10 kilowatts of power. It uses gasoline to generate the power that drives the lift motors, keeps backup batteries charged, and powers onboard electronics including computing, sensors, and communications equipment. The onboard batteries never need recharging; users just need to refill the gas tank and fly again. Flight control can operate in fully-or semi-autonomous modes.

With the hiring of several MIT alumni, the startup is quietly developing a 100-kilowatt hybrid drone that can lift 100 kilograms — enough to carry a human or two — for up to three hours. NASA, Uber, and many aerospace companies worldwide are currently working on building air taxis, small autonomous planes that will shuttle people around in big cities. But, Phan says, these can stay airborne for only about 10 minutes. Top Flight’s technologies will make them more practical for hauling people from hub to hub.

“With a 100-kilowatt hybrid electric engine, concepts like air taxis become viable,” he says. “By 2020, you may see a drone fly a person.”

“A Toyota Prius for the sky”

Top Flight’s story began in the late 2000s, when Phan was recalled to MIT twice to solve different engineering problems — both times leading to startups.

In 2009, Phan’s former advisor Sanjay Sarma, now the Fred Fort Flowers and Daniel Fort Flowers Professor in Mechanical Engineering and vice president for open learning, asked him to enroll in a PhD program to work on wide area thermal imaging. Phan’s research became a core of Phan and Sarma’s startup Essess, which deploys cars with thermal-imaging rooftop rigs that create heat maps of homes and buildings to detect energy leaks.

In 2014, Robert Shin, head of the Intelligence, Surveillance, Reconnaissance and Tactical Systems Division at MIT Lincoln Laboratory, approached Phan and asked him to help solve the payload and endurance problems for drones.

Phan and other MIT researchers took a shot at the problem by conceptualizing and designing microscale hybrid electric-gas engines for drones. “We said, ‘What if we build a Toyota Prius for the sky?’” Phan says, laughing.

Hybrid electric engines are easier to build in cars, because, among other things, there are fewer weight and volume restraints. Engines on drones must be small and lightweight while delivering the same amount of power. This produces major technical challenges with excessive vibration and heat. “Often the engine will literally melt because you’re running it so hot,” Phan says.

Using various heat transfer and control techniques — such as strategically incorporating small fans, cooling fins, and rubber vibration dampeners — the team solved those issues and initially slapped a prototype hybrid engine on a generic drone. Their calculations predicted the hybrid drone would fly for an hour — but it flew for nearly 2.5 hours.

“The lightbulb went off,” Phan says. “We were like, ‘What else can you do with a drone that can fly for hours?’”

Phan founded the startup in 2014, along with Sarma and other MIT engineers, and set up operations in a remote-controlled helicopter hobby shop in Malden, Massachusetts, before opening a separate headquarters in that city in 2016. A couple of funding rounds pushed them past $2 million of early venture funding by 2015.

Over the past several years, Top Flight has continued to develop major innovations for the microscale hybrid engine concept, called a “digital gearbox.” Engines for vertical takeoff aircraft, such as helicopters, are complex and difficult to manage, consisting of thousands of mechanical parts. Top Flight’s digital gearbox behaves like those systems but uses electricity to control everything. Gasoline runs to a small generator, creating electric power, which the digital gearbox controls and sends in pulses to the electric motors and electronics. This makes the powering flight much simpler and more efficient, Phan says.

“By pulsing the electricity to the motors, we can control the amount of torque and revolutions per minute of the motor,” Phan says. “We can … achieve the same benefits as a traditional mechanical transmission system, but it’s much more efficient, cost-effective, and scalable.”

Cruising in agile aerospace

Today, Top Flight operates in what it calls “agile aerospace 2.0,” a term representing the valuable vertical range for drones and microsatellites starting from the ground level and rising to 400 feet. Flying closer to the ground means greatly enhanced imaging and sensing resolutions, and other capabilities, such as communications. “If you go outside today, there’s virtually nothing happening in agile aerospace,” Phan says. “But it makes the most sense [for] air taxis or inspecting power lines, or doing logistics or delivery.”

Immediate applications for Top Flight’s drone capabilities may include inspecting infrastructure in remote areas. Some U.S. utilities companies are already tasking drones with inspecting power lines and pipelines that go without routine inspection due to their remote locations. Top Flight’s drones could greatly increase the range of those drones while reducing costs and improving worker safety. They could also help pre- and post-disaster recovery efforts by surveying damage to the networks after natural disasters.

As for delivery drones, Phan says Top Flight can increase the overall value related to increased range. Amazon, Google, UPS, and other large international firms are developing drone-based solutions that can deliver packages to consumer doorsteps. But they’re restricted to carrying, say, a single textbook and maybe 30 minutes of battery life, limiting their range.

“By increasing the range by an order of magnitude, you can capture 100 times more value, due to the increased area coverage, compared to traditional battery drone systems,” Phan says. “[Delivery drones] are not just a gimmick. They’re very feasible soon.”

Top Flight’s drones also hold promise for improved military missions, Phan says. A flock of 1,000 small drones could be deployed for longer times to gather reconnaissance data at a cost similar that of a single large military aircraft.

When Top Flight completes its 100-kilowatt hybrid electric engine, that same concept could also be used to haul, say, barrels of oil, divided into smaller amounts for military convoys in dangerous zones. Generally, this type of shipping is expensive and hazardous due to transportation costs and various risks on the road. “Instead of carrying really big loads in the tons, you use many drones to carry small loads in the 100-kilogram increments, like a pack of mules,” Phan says.

Currently, Top Flight uses an internal combustion engine in its microscale hybrid power systems. Moving forward, the company aims to hybridize gas turbine engines, which are used to power jets and helicopters. “Heat and vibration issues will be magnified, but at the same time they’re much more powerful and almost 100 percent more energy efficient than comparably-sized internal combustion engines,” Phan says. “That’s our next challenge.”

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Designing the microstructure of printed objects

Today’s 3-D printers have a resolution of 600 dots per inch, which means that they could pack a billion tiny cubes of different materials into a volume that measures just 1.67 cubic inches.

Such precise control of printed objects’ microstructure gives designers commensurate control of the objects’ physical properties — such as their density or strength, or the way they deform when subjected to stresses. But evaluating the physical effects of every possible combination of even just two materials, for an object consisting of tens of billions of cubes, would be prohibitively time consuming.

So researchers at MIT’s Computer Science and Artificial Intelligence Laboratory (CSAIL) have developed a new design system that catalogues the physical properties of a huge number of tiny cube clusters. These clusters can then serve as building blocks for larger printable objects. The system thus takes advantage of physical measurements at the microscopic scale, while enabling computationally efficient evaluation of macroscopic designs.

“Conventionally, people design 3-D prints manually,” says Bo Zhu, a postdoc at CSAIL and first author on the paper. “But when you want to have some higher-level goal — for example, you want to design a chair with maximum stiffness or design some functional soft [robotic] gripper — then intuition or experience is maybe not enough. Topology optimization, which is the focus of our paper, incorporates the physics and simulation in the design loop. The problem for current topology optimization is that there is a gap between the hardware capabilities and the software. Our algorithm fills that gap.”

Zhu and his MIT colleagues presented their work this week at Siggraph, the premier graphics conference. Joining Zhu on the paper are Wojciech Matusik, an associate professor of electrical engineering and computer science; Mélina Skouras, a postdoc in Matusik’s group; and Desai Chen, a graduate student in electrical engineering and computer science.

Researchers used their algorithm to design soft grippers with microstructures that can grasp objects by moving their tips when external forces are applied to their extremities. (The Computational Fabrication Group at MIT)

Points in space

The MIT researchers begin by defining a space of physical properties, in which any given microstructure will assume a particular location. For instance, there are three standard measures of a material’s stiffness: One describes its deformation in the direction of an applied force, or how far it can be compressed or stretched; one describes its deformation in directions perpendicular to an applied force, or how much its sides bulge when it’s squeezed or contract when it’s stretched; and the third measures its response to shear, or a force that causes different layers of the material to shift relative to each other.

Those three measures define a three-dimensional space, and any particular combination of them defines a point in that space.

In the jargon of 3-D printing, the microscopic cubes from which an object is assembled are called voxels, for volumetric pixels; they’re the three-dimensional analogue of pixels in a digital image. The building blocks from which Zhu and his colleagues assemble larger printable objects are clusters of voxels.

In their experiments, the researchers considered clusters of three different sizes — 16, 32, and 64 voxels to a face. For a given set of printable materials, they randomly generate clusters that combine those materials in different ways: a square of material A at the cluster’s center, a border of vacant voxels around that square, material B at the corners, or the like. The clusters must be printable, however; it wouldn’t be possible to print a cluster that, say, included a cube of vacant voxels with a smaller cube of material floating at its center.

For each new cluster, the researchers evaluate its physical properties using physics simulations, which assign it a particular point in the space of properties.

Gradually, the researchers’ algorithm explores the entire space of properties, through both random generation of new clusters and the principled modification of clusters whose properties are known. The end result is a cloud of points that defines the space of printable clusters.

The soft mechanisms for flapping wings are embedded in the material by topology optimization. The wings of the ray are specified to flap up and down when vertices on its spine contract and expand. (The Computational Fabrication Group at MIT)

Establishing boundaries

The next step is to calculate a function called the level set, which describes the shape of the point cloud. This enables the researchers’ system to mathematically determine whether a cluster with a particular combination of properties is printable or not.

The final step is the optimization of the object to be printed, using software custom-developed by the researchers. That process will result in specifications of material properties for tens or even hundreds of thousands of printable clusters. The researchers’ database of evaluated clusters may not contain exact matches for any of those specifications, but it will contain clusters that are extremely good approximations.

“The design and discovery of structures to produce materials and objects with exactly specified functional properties is central for a large number of applications where mechanical properties are important, such as in the automotive or aerospace industries,” says Bernd Bickel, an assistant professor of computer science at the Institute of Science and Technology Austria and head of the institute’s Computer Graphics and Digital Fabrication group. “Due to the complexity of these structures, which, in the case of 3-D printing, can consist of more than a trillion material droplets, exploring them manually is absolutely intractable.”

“The solution presented by Bo and colleagues addresses this problem in a very clever way, by reformulating it,” he says. “Instead of working directly on the scale of individual droplets, they first precompute the behavior of small structures and put it in a database. Leveraging this knowledge, they can perform the actual optimization on a coarser level, allowing them to very efficiently generate high-resolution printable structures with more than a trillion elements, even with just a regular computer. This opens up exciting new avenues for designing and optimizing structures at a resolution that was out of reach so far.”

The MIT researchers’ work was supported by the U.S. Defense Advanced Research Projects Agency’s SIMPLEX program.

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Startup soars with LEGO drones

Like many kids, Amir Hirsch ’06, SM ’07 grew up playing with LEGOs. But unlike many adults, is still playing with them as part of his job as CEO and co-founder of Flybrix. Started in 2015, the company sells kits for children and adults alike to build their own reusable drones out of the popular plastic building bricks.

“It lets you tinker around with LEGOs, come up with a design you like, and see it fly,” Hirsch says.

In addition to the LEGOs, Flybrix kits come with all the parts necessary to build a drone and make it fly, including motors, a fully-routed Arduino board, and a lithium polymer battery.

Learning opportunities abound. Builders gain insight into the aerodynamics of the drone’s fan, the electromechanics necessary to control a motor, and flight basics including balance and feedback. Hirsch, who double-majored in mathematics and electrical engineering and computer science (EECS) for his bachelor's and earned a master's in EECS, says such concepts become much clearer when actually flying a drone built by hand.

“You really feel the feedback system trying to keep it stable,” he says.

But what goes up must come down. The average Flybrix drone can stay up for five minutes.

“Most of the time when I’m flying something, people ask that I crash it into the wall,” said Hirsch who earned his degrees in electrical engineering and computer science as well as mathematics. “Because they all want to see it shatter into a lot of pieces.”

All of the kit’s pieces can be reused to build another drone. To date, Hirsch has only lost one.

“I flew one that’s [stuck] just above the white board [of our office] … it’s not accessible unless you take down the wall,” he says.

In 2016, the company sold more than 8,000 drone kits online and hopes to be in many national retail chains this December. Flybrix has sold nearly 500 units to school systems around the world, including many in STEM-focused school programs in Australia.

While the company primarily targets young people 14 years and older, Hirsch says he expects interest from other areas. “I bet you that retired pilots are our best demographic,” he says.

Flybrix is not Hirsch’s first startup. In 2011, he founded Zigfu, which received seed funding through Ycombinator to build and market an application programming interface (API) that aids developers of motion games and gesture user interfaces. Prior to that, he founded a company that made educational iPad apps.

He recalls some advice he received from an MIT alumnus as being integral to his career, even before he caught the startup bug. He summarized the conversation in a 2013 blog post that was later picked up by Forbes.

“You have to think about building up a market approach for how to get customers … and how to use technology to build a defensible position,” he says. “Technology is not a prerequisite for business success, but marketing is.”

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Fast, noninvasive technique for probing cells may reveal disease

The stiffness or elasticity of a cell can reveal much about whether the cell is healthy or diseased. Cancer cells, for instance, are known to be softer than normal, while asthma-affected cells can be rather stiff.

Determining the mechanical properties of cells may thus help doctors diagnose and track the progression of certain diseases. Current methods for doing this involve directly probing cells with expensive instruments, such as atomic force microscopes and optical tweezers, which make direct, invasive contact with the cells.

Now MIT engineers have devised a way to assess a cell’s mechanical properties simply by observation. The researchers use standard confocal microscopy to zero in on the constant, jiggling motions of a cell’s particles — telltale movements that can be used to decipher a cell’s stiffness. Unlike optical tweezers, the team’s technique is noninvasive, running little risk of altering or damaging a cell while probing its contents.

“There are several diseases, like certain types of cancer and asthma, where stiffness of the cell is known to be linked to the phenotype of the disease,” says Ming Guo, the Brit and Alex d'Arbeloff Career Development Assistant Professor in MIT’s Department of Mechanical Engineering. “This technique really opens a door so that a medical doctor or biologist, if they would like to know the material property of cell in a very quick, noninvasive way, can now do it.”

Guo and graduate student Satish Kumar Gupta have published their results in the Journal of the Mechanics and Physics of Solids.

Stirring spoons

In his 1905 PhD thesis, Albert Einstein derived a formula, known as the Stokes-Einstein equation, that makes it possible to calculate a material’s mechanical properties by observing and measuring the movement of particles in that material. There’s just one catch: The material must be “in equilibrium,” meaning that any particle motions must be due to the effect of the material’s temperature rather than any external forces acting on the particles.

“You can think of equilibrium as being a hot cup of coffee,” Guo says. “The coffee’s temperature alone can drive sugar to disperse. Now if you stir the coffee with a spoon, the sugar dissolves faster, but the system is not driven solely by temperature any more and is no longer in equilibrium. You’re changing the environment, putting energy in and making the reaction happen faster.”

Within a cell, organelles such as mitochondria and lysosomes are constantly jiggling in response to the cell’s temperature. However, Guo says, there are also “many minispoons” stirring up the surrounding cytoplasm, in the form of proteins and molecules that, every so often, actively push vibrating organelles around like billiard balls.

The constant blur of activity in a cell has made it difficult for scientists to discern, simply by looking, which motions are due to temperature and which are due to more active, “spoon-like” processes. This limitation, Guo says, has “basically shut the door on using Einstein’s equation and pure observation to measure a cell’s mechanical properties.”

Frame by frame

Guo and Gupta surmised that there might be a way to tease out temperature-driven motions in a cell by looking at the cell within a very narrow timeframe. They realized that particles energized solely by temperature exhibit a constant jiggling motion. No matter when you look at a temperature-driven particle, it’s bound to be moving.

In contrast, active processes that can knock a particle around a cell’s cytoplasm do so only occasionally. Seeing such active movements, they hypothesized, would require looking at a cell over a longer timeframe.

To test their hypothesis, the researchers carried out experiments on human melanoma cells, a line of cancer cells they chose for their ability to grow easily and quickly. They injected small polymer particles into each cell, then tracked their motions under a standard confocal fluorescent microscope. They also varied the cells’ stiffness by introducing salt into the cell solution — a process that draws water out of cells, making them more compressed and stiff.

The researchers recorded videos of the cells at different frame rates and observed how the particles’ motions changed with cell stiffness. When they watched the cells at frequencies higher than 10 frames per second, they mostly observed particles jiggling in place; these vibrations appeared to be caused by temperature alone. Only at slower frame rates did they spot more active, random movements, with particles shooting across wider distances within the cytoplasm.

For each video, they tracked the path of a particle and applied an algorithm they had developed to calculate the particle’s average travel distance. They then plugged this motion value into a generalized format of the Stokes-Einstein equation.

Guo and Gupta compared their calculations of stiffness with actual measurements they made using optical tweezers. Their calculations matched up with measurements only when they used the motion of particles captured at frequencies of 10 frames per second and higher. Guo says this suggests that particle motions occurring at high frequencies are indeed temperature-driven.

The team’s results suggest that if researchers observe cells at fast enough frame rates, they can isolate particle motions that are purely driven by temperature, and determine their average displacement — a value that can be directly plugged into Einstein’s equation to calculate a cell’s stiffness.

“Now if people want to measure the mechanical properties of cells, they can just watch them,” Guo says.

The team is now working with doctors at Massachusetts General Hospital, who hope to use the new, noninvasive technique to study cells involved in cancer, asthma, and other conditions in which cell properties change as a disease progresses. 

“People have an idea that structure changes, but doctors want to use this method to demonstrate whether there is a change, and whether we can use this to diagnose these conditions,” Guo says.

This research was funded, in part, by MIT’s Department of Mechanical Engineering.

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Deadly heat waves could hit South Asia this century

In South Asia, a region of deep poverty where one-fifth of the world’s people live, new research suggests that by the end of this century climate change could lead to summer heat waves with levels of heat and humidity that exceed what humans can survive without protection.

There is still time to avert such severe warming if measures are implemented now to reduce the most dire consequences of global warming. However, under business-as-usual scenarios, without significant reductions in carbon emissions, the study shows these deadly heat waves could begin within as little as a few decades to strike regions of India, Pakistan, and Bangladesh, including the fertile Indus and Ganges river basins that produce much of the region’s food supply.

The new findings, based on detailed computer simulations using the best available global circulation models, are described this week in the journal Science Advances, in a paper by Elfatih Eltahir, a professor of civil and environmental engineering at MIT; Eun Soon Im, a former researcher at the Singapore-MIT Alliance for Research and Technology and now a professor at the Hong Kong University of Science and Technology; and Jeremy Pal, a professor at Loyola Marymount University in Los Angeles.

The study follows an earlier report by Eltahir and his team that looked at projected heat waves in the Persian Gulf region. While the number of extreme-heat days projected for that region was even worse than for South Asia, Eltahir says the impact in the latter area could be vastly more severe. That’s because while the Persian Gulf area has a relatively small, relatively wealthy population and little agricultural land, the areas likely to be hardest hit in northern India, Bangladesh, and southern Pakistan are home to 1.5 billion people. These areas are also among the poorest in the region, with much of the population dependent on subsistence farming that requires long hours of hard labor out in the open and unprotected from the sun.

“That makes them very vulnerable to these climatic changes, assuming no mitigation,” says Eltahir, who spoke with MIT News from Singapore, where he is carrying out follow-up research on potential climate effects in that area.

While the projections show the Persian Gulf may become the region of the worst heat waves on the planet, northern India is a close second, Eltahir says, and eastern China, also densely populated, is third. But the highest concentrations of heat in the Persian Gulf would be out over the waters of the Gulf itself, with lesser levels over inhabited land.

The new analysis is based on recent research showing that hot weather’s most deadly effects for humans comes from a combination of high temperature and high humidity, an index which is measured by a reading known as wet-bulb temperature. This reflects the ability of moisture to evaporate, which is the mechanism required for the human body to maintain its internal temperature through the evaporation of sweat. At a wet-bulb temperature of 35 degrees Celsius (95 degrees Fahrenheit), the human body cannot cool itself enough to survive more than a few hours.

A previous study of temperature and humidity records show that in today’s climate, wet-bulb temperatures have rarely exceeded about 31 C anywhere on Earth. While the earlier report from Eltahir and his colleagues showed that this survivability limit would start to be exceeded occasionally in the Persian Gulf region by the end of this century, actual readings there in the summer of 2015 showed that the 35-degree wet-bulb limit had almost been reached already, suggesting that such extremes could begin happening earlier than projected. The summer of 2015 also produced one of the deadliest heat waves in history in South Asia, killing an estimated 3,500 people in Pakistan and India.

And yet, India and China remain two countries where emission rates of greenhouse gases continue to rise, driven mostly by economic growth, Eltahir says. “So I think these results pose a dilemma for countries like India. Global warming is not just a global problem — for them, they will have some of the hottest spots” on the planet. In fact, a separate study by researchers at the University of California at Irvine and elsewhere, published recently also in Scientific Advances, reached similar conclusions based on a different kind of analysis using recent weather records.

That paper was “complementary to ours, which is based on modeling,” Eltahir says. The new analysis looked at results from three of the more than 20 comprehensive global climate models, which were selected because they most accurately matched actual weather data from the South Asian region. The study shows that by century’s end, absent serious reductions in global emissions, the most extreme, once-in-25-years heat waves would increase from wet-bulb temperatures of about 31 C to 34.2 C. “It brings us close to the threshold” of survivability, he says, and “anything in the 30s is very severe.”

In today’s climate, about 2 percent of the Indian population sometimes gets exposed to extremes of 32-degree wet-bulb temperatures. According to this study, by 2100 that will increase to about 70 percent of the population, and about 2 percent of the people will sometimes be exposed to the survivability limit of 35 degrees. And because the region is important agriculturally, it’s not just those directly affected by the heat who will suffer, Eltahir says: “With the disruption to the agricultural production, it doesn’t need to be the heat wave itself that kills people. Production will go down, so potentially everyone will suffer.”

But while the study provides a grim warning about what could happen, it is far from inevitable, Eltahir stresses. The study examined not just the “business as usual” case but also the effects under a moderate  mitigation scenario, which showed that these dramatic, deadly effects can still be averted. “There is value in mitigation, as far as public health and reducing heat waves,” he says. “With mitigation, we hope we will be able to avoid these severe projections. This is not something that is unavoidable.”

“This study provides vitally important information for planning for a hot, wet future in South Asia,” says Matthew Huber, a professor of earth, atmospheric, and planetary sciences at Purdue University, who was not involved in this research  “The results are impressive and, frankly, oppressive,” he says. “The study shows that unfettered warming is likely to do substantial harm to the health and well-being of the most populous democracy on Earth. This is very bad news.”

The research was supported by the National Research Foundation Singapore through the Singapore-MIT Alliance for Research and Technology (SMART).

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Three MIT scientists honored with John Dawson Award for Excellence in Plasma Physics Research

Three members of MIT's Plasma Science and Fusion Center (PSFC) High-Energy-Density Physics Division have been honored with the American Physical Society’s John Dawson Award for Excellence in Plasma Physics Research. Division head and Senior Research Scientist Richard Petrasso, Senior Research Scientist Chikang Li, and Research Scientist Fredrick Seguin were selected, along with three colleagues from other laboratories, to share the award for “the pioneering use of proton radiography to reveal new aspects of flows, instabilities, and fields in high-energy-density (HED) plasmas.”

The three PSFC researchers study the physics of inertial confinement fusion (ICF) plasmas and HED plasmas, collaborating with laser facilities like OMEGA at the Laboratory for Laser Energetics (LLE) and the National Ignition Facility at Lawrence Livermore National Laboratory (LLNL). Because these plasmas occur on such short time-scales they are challenging to evaluate. To help probe and examine the condition and evolution of these plasmas, and other phenomena, the PSFC team has developed what Petrasso calls a “multiple-monoenergetic-particle source (MMPS).”

“The MMPS is a backlighter, which allows us to irradiate experiments in order to better understand plasma structure and evolution,” says Petrasso. “It is especially useful for looking at plasma phenomena that happen on the order of a nanosecond or so. That phenomenon could be an ICF implosion, magnetic reconnection, or a lab astro experiment.”

Co-recipient Chikang Li, who used the MMPS for his recent exploration of the Crab Nebula in the constellation Taurus, expressed his pleasure that the community recognizes the importance of their work and contributions to the field. “I am even more glad that, as already indicated by numerous publications, this technique provides a unique and powerful diagnostic for the HED community,” Li says.

Petrasso credits LLE, LLNL, and other collaborators for their support and involvement with PSFC research, as well as the National Nuclear Security Administration of the Department of Energy, which has funded much of their work since the early 1990s. “Even though the three of us have been singled out, it really has been a broad effort, and very importantly one in which our students have been able to capitalize.” Two recent MIT graduates, Mario Manuel SM '08 PhD '13 and Mike Rosenberg PhD '14 received the American Physical Society Rosenbluth Outstanding Doctoral Thesis Award in 2014 and 2016, respectively, for research that employed the MMPS. Alex Zylstra PhD '15 has been nominated for the 2017 award for a thesis that also uses this technology.

“The PSFC has been a wonderful place, with great infrastructure to support this work,” notes Petrasso. “We are always trying to push the frontiers, and finding exciting opportunities for our students. Our success is measured by the impact our students make in the outside community. And trust me, they are having a big impact.”

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