3-D printing with cellulose

For centuries, cellulose has formed the basis of the world’s most abundantly printed-on material: paper. Now, thanks to new research at MIT, it may also become an abundant material to print with — potentially providing a renewable, biodegradable alternative to the polymers currently used in 3-D printing materials.

“Cellulose is the most abundant organic polymer in the world,” says MIT postdoc Sebastian Pattinson, lead author of a paper describing the new system in the journal Advanced Materials Technologies. The paper is co-authored by associate professor of mechanical engineering A. John Hart, the Mitsui Career Development Professor in Contemporary Technology.

Cellulose, Pattinson explains, is “the most important component in giving wood its mechanical properties. And because it’s so inexpensive, it’s biorenewable, biodegradable, and also very chemically versatile, it’s used in a lot of products. Cellulose and its derivatives are used in pharmaceuticals, medical devices, as food additives, building materials, clothing — all sorts of different areas. And a lot of these kinds of products would benefit from the kind of customization that additive manufacturing [3-D printing] enables.”

Meanwhile, 3-D printing technology is rapidly growing. Among other benefits, it “allows you to individually customize each product you make,” Pattinson says.

Using cellulose as a material for additive manufacturing is not a new idea, and many researchers have attempted this but faced major obstacles. When heated, cellulose thermally decomposes before it becomes flowable, partly because of the hydrogen bonds that exist between the cellulose molecules. The intermolecular bonding also makes high-concentration cellulose solutions too viscous to easily extrude.

Instead, the MIT team chose to work with cellulose acetate — a material that is easily made from cellulose and is already widely produced and readily available. Essentially, the number of hydrogen bonds in this material has been reduced by the acetate groups. Cellulose acetate can be dissolved in acetone and extruded through a nozzle. As the acetone quickly evaporates, the cellulose acetate solidifies in place. A subsequent optional treatment replaces the acetate groups and increases the strength of the printed parts.

“After we 3-D print, we restore the hydrogen bonding network through a sodium hydroxide treatment,” Pattinson says. “We find that the strength and toughness of the parts we get … are greater than many commonly used materials” for 3-D printing, including acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA).

To demonstrate the chemical versatility of the production process, Pattinson and Hart added an extra dimension to the innovation. By adding a small amount of antimicrobial dye to the cellulose acetate ink, they 3-D-printed a pair of surgical tweezers with antimicrobial functionality.

“We demonstrated that the parts kill bacteria when you shine fluorescent light on them,” Pattinson says. Such custom-made tools “could be useful for remote medical settings where there’s a need for surgical tools but it’s difficult to deliver new tools as they break, or where there’s a need for customized tools. And with the antimicrobial properties, if the sterility of the operating room is not ideal the antimicrobial function could be essential,” he says.

Because most existing extrusion-based 3-D printers rely on heating polymer to make it flow, their production speed is limited by the amount of heat that can be delivered to the polymer without damaging it. This room-temperature cellulose process, which simply relies on evaporation of the acetone to solidify the part, could potentially be faster, Pattinson says. And various methods could speed it up even further, such as laying down thin ribbons of material to maximize surface area, or blowing hot air over it to speed evaporation. A production system would also seek to recover the evaporated acetone to make the process more cost effective and environmentally friendly.

Cellulose acetate is already widely available as a commodity product. In bulk, the material is comparable in price to that of thermoplastics used for injection molding, and it’s much less expensive than the typical filament materials used for 3-D printing, the researchers say. This, combined with the room-temperature conditions of the process and the ability to functionalize cellulose in a variety of ways, could make it commercially attractive.

The research was supported by the National Science Foundation.

de MIT News http://ift.tt/2mmqcs5

Graphene sheets capture cells efficiently

A single cell can contain a wealth of information about the health of an individual. Now, a new method developed at MIT and National Chiao Tung University could make it possible to capture and analyze individual cells from a small sample of blood, potentially leading to very low-cost diagnostic systems that could be used almost anywhere.

The new system, based on specially treated sheets of graphene oxide, could ultimately lead to a variety of simple devices that could be produced for as little as $5 apiece and perform a variety of sensitive diagnostic tests even in places far from typical medical facilities.

The material used in this research is an oxidized version of the two-dimensional form of pure carbon known as graphene, which has been the subject of widespread research for over a decade because of its unique mechanical and electrical characteristics. The key to the new process is heating the graphene oxide at relatively mild temperatures. This low-temperature annealing, as it is known, makes it possible to bond particular compounds to the material’s surface. These compounds in turn select and bond with specific molecules of interest, including DNA and proteins, or even whole cells. Once captured, those molecules or cells can then be subjected to a variety of tests.

The findings are reported in the journal ACS Nano, in a paper co-authored by Neelkanth Bardhan, an MIT postdoc, and Priyank Kumar PhD ’15, now a postdoc at ETH Zurich; Angela Belcher, the James Mason Crafts Professor in biological engineering and materials science and engineering at MIT and a member of the Koch Institute for Integrative Cancer Research; Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems at MIT; Hidde L. Ploegh, a professor of biology and member of the Whitehead Institute for Biomedical Research; Guan-Yu Chen, an assistant professor in biomedical engineering at National Chiao Tung University in Taiwan; and Zeyang Li, a doctoral student at the Whitehead Institute.

Other researchers have been trying to develop diagnostic systems using a graphene oxide substrate to capture specific cells or molecules, but these approaches used just the raw, untreated material. Despite a decade of research, other attempts to improve such devices’ efficiency have relied on external modifications, such as surface patterning through lithographic fabrication techniques, or adding microfluidic channels, which add to the cost and complexity. The new finding offers a mass-producible, low-cost approach to achieving such improvements in efficiency.

The heating process changes the material’s surface properties, causing oxygen atoms to cluster together, leaving spaces of bare graphene between them. This makes it relatively easy to attach other chemicals to the surface, which can interact with specific molecules of interest. The new research demonstrates how that basic process could potentially enable a suite of low-cost diagnostic systems, for example for cancer screening or treatment follow-up.

For this proof-of-concept test, the team used molecules that can quickly and efficiently capture specific immune cells that are markers for certain cancers. They were able to demonstrate that their treated graphene oxide surfaces were almost twice as effective at capturing such cells from whole blood, compared to devices fabricated using ordinary, untreated graphene oxide, says Bardhan, the paper’s lead author.

The system has other advantages as well, Bardhan says. It allows for rapid capture and assessment of cells or biomolecules under ambient conditions within about 10 minutes and without the need for refrigeration of samples or incubators for precise temperature control. And the whole system is compatible with existing large-scale manufacturing methods, making it possible to produce diagnostic devices for less than $5 apiece, the team estimates. Such devices could be used in point-of-care testing or resource-constrained settings.

Existing methods for treating graphene oxide to allow functionalization of the surface require high temperature treatments or the use of harsh chemicals, but the new system, which the group has patented, requires no chemical pretreatment and an annealing temperature of just 50 to 80 degrees Celsius (122 to 176 F).

While the team’s basic processing method could make possible a wide variety of applications, including solar cells and light-emitting devices, for this work the researchers focused on improving the efficiency of capturing cells and biomolecules that can then be subjected to a suite of tests. They did this by enzymatically coating the treated graphene oxide surface with peptides called nanobodies — subunits of antibodies, which can be cheaply and easily produced in large quantities in bioreactors and are highly selective for particular biomolecules.

The researchers found that increasing the annealing time steadily increased the efficiency of cell capture: After nine days of annealing, the efficiency of capturing cells from whole blood went from 54 percent, for untreated graphene oxide, to 92 percent for the treated material.

The team then performed molecular dynamics simulations to understand the fundamental changes in the reactivity of the graphene oxide base material. The simulation results, which the team also verified experimentally, suggested that upon annealing, the relative fraction of one type of oxygen (carbonyl) increases at the expense of the other types of oxygen functional groups (epoxy and hydroxyl) as a result of the oxygen clustering. This change makes the material more reactive, which explains the higher density of cell capture agents and increased efficiency of cell capture.

“Efficiency is especially important if you’re trying to detect a rare event,” Belcher says. “The goal of this was to show a high efficiency of capture.” The next step after this basic proof of concept, she says, is to try to make a working detector for a specific disease model.

In principle, Bardhan says, many different tests could be incorporated on a single device, all of which could be placed on a small glass slide like those used for microscopy.

“I think the most interesting aspect of this work is the claimed clustering of oxygen species on graphene sheets and its enhanced performance in surface functionalization and cell capture,” says Younan Xia, a professor of chemistry and biochemistry at Georgia Institute of Technology who was not involved in this work. “It is an interesting idea.”

The work was supported by the Army Research Office Institute for Collaborative Biotechnologies and MIT’s Tata Center and Solar Frontiers Center.

de MIT News http://ift.tt/2mU86Ke

Study: Volkswagen’s excess emissions will lead to 1,200 premature deaths in Europe

In September 2015, the German Volkswagen Group, the world’s largest car producer, admitted to having installed “defeat devices” in 11 million diesel cars sold worldwide between 2008 and 2015. The devices were designed to detect and adapt to laboratory tests, making the cars appear to comply with environmental standards when, in fact, they emitted pollutants called nitric oxides, or NO_x, at levels that were on average four times the applicable European test-stand limit.

While Volkswagen has issued recalls of affected vehicles in both the U.S. and Europe, scientists at MIT and elsewhere have found the excess emissions has already had an impact on public health. The team previously estimated that the excess emissions generated by 482,000 affected vehicles sold in the U.S. will cause approximately 60 premature deaths across the U.S.

Now the researchers have looked closer to Volkswagen’s home base, examining the health impact from the 2.6 million affected cars sold in Germany under Volkswagen Group’s brands VW, Audi, Skoda, and Seat. In a paper published today in Environmental Research Letters, the team reports that the manufacturer’s emissions in excess of the test-stand limit value have had a significant effect on public health not just in Germany but across Europe.

The researchers estimate that 1,200 people in Europe will die early, each losing as much as a decade of their life, as a result of excess emissions generated between 2008 and 2015 by affected cars sold in Germany. Of these premature deaths, 500 will likely occur in Germany, meaning that more than 60 percent of premature mortalities stemming from those German-sold cars will occur in neighboring countries, most notably Poland, France, and the Czech Republic.

“Air pollution is very much transboundary,” says co-author Steven Barrett, the Leonardo-Finmeccanica Associate Professor of Aeronautics and Astronautics at MIT. “[Pollution] doesn’t care about political boundaries; it just goes straight past. Thus, a car in Germany can easily have significant impacts in neighboring countries, especially in densely populated areas such as the European continent.”

If Volkswagen can recall and retrofit affected vehicles to meet European standards by the end of 2017, this would avert 2,600 additional premature deaths, or 29,000 life years lost, and 4.1 billion Euros in corresponding health costs, which would otherwise be expected in the absence of a recall.  

Barrett’s co-authors from MIT are lead author and graduate student Guillaume Chossière, postdoc Akshay Ashok, research assistant Irene Dedoussi, and research scientist Raymond Speth. Sebastian Eastham of Harvard University and Robert Malina of Hasselt University in Belgium are also co-authors.

Something in the air

Barrett says that it’s not surprising that Germany, and Europe as a whole, incur higher health impacts from Volkswagen’s excess emissions, as compared to the U.S. Not only were more affected cars sold in Germany (2.6 million) than in the U.S. (482,000), differences in population density, driving behavior, and atmospheric conditions also help explain the aggravated health impacts across Europe.

For instance, Europe’s average population density is about three times higher than the U.S. average, and historical data has shown that diesel cars in Germany are driven on average 20 percent more, in terms of annual mileage, compared to the average American car that was considered in the U.S. study. In other words, there are more affected cars on the road, generating emissions that affect a higher concentration of people.

Atmospheric conditions play a role, as well. NO_x is emitted from the engine as a gas, which can be carried by winds over long distances before or while reacting with ammonia in the air to form fine particulates. Since the atmosphere in Europe happens to contain more ammonia than in the U.S., more fine particulates may form from a given amount of NO_x. It is exposure to these fine particulates which has been shown to cause cardiopulmonary and respiratory disease. NO_x emissions also contribute to the formation of ozone, another pollutant known to be detrimental to human health.

“It takes time for NO_x to get converted into particulates, at which point, they could be 100 to 200 kilometers or further away from their source,” Barrett says.

Excess emissions’ health effects

The researchers arrived at their mortality estimates using a method similar to the one they adopted to assess Volkswagen’s health impacts in the U.S. The team based their analysis in part on the German Federal Motor Transport Authority’s measurements of emissions from Volkswagen cars.

They then used historical data on driving behavior in Germany to estimate the number of kilometers driven by each car per year and where drivers were likely to drive the most. From that, the researchers generated a map of excess emissions within Germany.

Barrett and his colleagues worked this emissions map into a simulation of the atmosphere, modeling where the NO_x emissions traveled, given prevailing winds, temperature, and precipitation, and where the gas interacted with other compounds to form fine particulates and ozone.

The atmospheric models produced a map of fine particulates and a map of ozone, which the team then overlaid on population density maps across Europe. With these maps, they calculated people’s exposure to Germany-derived excess emissions, for each country in the European Union. From these exposure estimates, the researchers calculated the increased risk of dying early in the population, using a “concentration response function” — a relationship between a person’s exposure to a given dose of a pollutant and the person’s related health risk.

“It ends up being about a one percent extra risk of dying early in a given year, per microgram per meter cubed of fine particles you’re exposed to,” Barrett says. “Typically that means that someone who dies early from air pollution ends up dying about a decade early.”

Volkswagen and beyond

Overall, the researchers found that 1,200 premature deaths will likely occur as a result of excess emissions that have already been released into the atmosphere between 2008 and 2015. Of these, 500 early deaths occur in Germany, followed by 160 in Poland, 84 in France, and 72 in the Czech Republic, with the remainder split among other European countries.

The researchers performed the same analysis a second time, under a scenario in which Volkswagen fixes affected cars to meet regulatory standards by the end of 2017, generating no excess emissions starting in January 2018. Under this scenario, the company would avert 2,600 premature deaths, or 29,000 years of life lost.

Going forward, the researchers plan to expand their study of auto emissions’ health impact, concentrating on diesel vehicles in Europe.

“It seems unlikely that Volkswagen is the only company with issues with excess emissions,” Barrett says. “We don’t know if other manufacturers have these defeat devices, but there is already evidence that many other vehicles in practice emit more than the applicable test-stand limit value. So we’re trying to do this for all diesel vehicles.”

de MIT News http://ift.tt/2lA7YyC

Precise technique tracks dopamine in the brain

MIT researchers have devised a way to measure dopamine in the brain much more precisely than previously possible, which should allow scientists to gain insight into dopamine’s roles in learning, memory, and emotion.

Dopamine is one of the many neurotransmitters that neurons in the brain use to communicate with each other. Previous systems for measuring these neurotransmitters have been limited in how long they provide accurate readings and how much of the brain they can cover. The new MIT device, an array of tiny carbon electrodes, overcomes both of those obstacles.

“Nobody has really measured neurotransmitter behavior at this spatial scale and timescale. Having a tool like this will allow us to explore potentially any neurotransmitter-related disease,” says Michael Cima, the David H. Koch Professor of Engineering in the Department of Materials Science and Engineering, a member of MIT’s Koch Institute for Integrative Cancer Research, and the senior author of the study.

Furthermore, because the array is so tiny, it has the potential to eventually be adapted for use in humans, to monitor whether therapies aimed at boosting dopamine levels are succeeding. Many human brain disorders, most notably Parkinson’s disease, are linked to dysregulation of dopamine.

“Right now deep brain stimulation is being used to treat Parkinson’s disease, and we assume that that stimulation is somehow resupplying the brain with dopamine, but no one’s really measured that,” says Helen Schwerdt, a Koch Institute postdoc and the lead author of the paper, which appears in the journal Lab on a Chip.

Studying the striatum

For this project, Cima’s lab teamed up with David H. Koch Institute Professor Robert Langer, who has a long history of drug delivery research, and Institute Professor Ann Graybiel, who has been studying dopamine’s role in the brain for decades with a particular focus on a brain region called the striatum. Dopamine-producing cells within the striatum are critical for habit formation and reward-reinforced learning.

Until now, neuroscientists have used carbon electrodes with a shaft diameter of about 100 microns to measure dopamine in the brain. However, these can only be used reliably for about a day because they produce scar tissue that interferes with the electrodes’ ability to interact with dopamine, and other types of interfering films can also form on the electrode surface over time. Furthermore, there is only about a 50 percent chance that a single electrode will end up in a spot where there is any measurable dopamine, Schwerdt says.

The MIT team designed electrodes that are only 10 microns in diameter and combined them into arrays of eight electrodes. These delicate electrodes are then wrapped in a rigid polymer called PEG, which protects them and keeps them from deflecting as they enter the brain tissue. However, the PEG is dissolved during the insertion so it does not enter the brain.

These tiny electrodes measure dopamine in the same way that the larger versions do. The researchers apply an oscillating voltage through the electrodes, and when the voltage is at a certain point, any dopamine in the vicinity undergoes an electrochemical reaction that produces a measurable electric current. Using this technique, dopamine’s presence can be monitored at millisecond timescales.

Using these arrays, the researchers demonstrated that they could monitor dopamine levels in many parts of the striatum at once.

“What motivated us to pursue this high-density array was the fact that now we have a better chance to measure dopamine in the striatum, because now we have eight or 16 probes in the striatum, rather than just one,” Schwerdt says.

The researchers found that dopamine levels vary greatly across the striatum. This was not surprising, because they did not expect the entire region to be continuously bathed in dopamine, but this variation has been difficult to demonstrate because previous methods measured only one area at a time.

How learning happens

The researchers are now conducting tests to see how long these electrodes can continue giving a measurable signal, and so far the device has kept working for up to two months. With this kind of long-term sensing, scientists should be able to track dopamine changes over long periods of time, as habits are formed or new skills are learned.

“We and other people have struggled with getting good long-term readings,” says Graybiel, who is a member of MIT’s McGovern Institute for Brain Research. “We need to be able to find out what happens to dopamine in mouse models of brain disorders, for example, or what happens to dopamine when animals learn something.”

She also hopes to learn more about the roles of structures in the striatum known as striosomes. These clusters of cells, discovered by Graybiel many years ago, are distributed throughout the striatum. Recent work from her lab suggests that striosomes are involved in making decisions that induce anxiety.

This study is part of a larger collaboration between Cima’s and Graybiel’s labs that also includes efforts to develop injectable drug-delivery devices to treat brain disorders.

“What links all these studies together is we’re trying to find a way to chemically interface with the brain,” Schwerdt says. “If we can communicate chemically with the brain, it makes our treatment or our measurement a lot more focused and selective, and we can better understand what’s going on.”

Other authors of the paper are McGovern Institute research scientists Minjung Kim, Satoko Amemori, and Hideki Shimazu; McGovern Institute postdoc Daigo Homma; McGovern Institute technical associate Tomoko Yoshida; and undergraduates Harshita Yerramreddy and Ekin Karasan.

The research was funded by the National Institutes of Health, the National Institute of Biomedical Imaging and Bioengineering, and the National Institute of Neurological Disorders and Stroke.

de MIT News http://ift.tt/2mgTqYJ

MIT's Jacqueline Hewitt and HERA team given $6M boost to detect cosmic dawn

This week, the Hydrogen Epoch of Reionization Array (HERA) telescope project team was awarded a grant from the Gordon and Betty Moore Foundation to MIT to expand the HERA telescope in South Africa to begin looking for the effects of light from the first generation of stars that formed in the universe.

HERA, an international project led by researchers at the University of California at Berkeley, with initial funding from the National Science Foundation (NSF), is looking for signals from the “epoch of reionization” (EoR) when 90 percent of the hydrogen atoms created in the early universe were destroyed by the first luminous stars and black holes. The enhancement of the array, supported by the additional funding and carried out in partnership with MIT, the University of Virginia, and the National Radio Astronomy Observatory, will increase HERA's capability in several different ways.

“Expanding HERA will help us map bubbles of ionization around early galaxies in our universe and will extend our ability to find the earliest signs of star formation in our universe,” said Aaron Parsons, lead investigator on the HERA project and associate professor of astronomy at UC Berkeley, who noted the importance of collecting area and bandwidth for accessing a cosmological signal roughly 100,000 times fainter than emission from the Milky Way and nearby galaxies. 

With the grant from the Moore Foundation, the team can increase the sensitivity of the array and potentially detect signals coming from a time before the EoR in the history of the universe, the cosmic dawn, roughly 400 million years after the Big Bang. Using this next-generation in instrumentation for 21-cm cosmology — the wavelength of neutral hydrogen gas radio waves — HERA will probe the 3-D structure of the universe during the very first appearance of stars, galaxies, and black holes. This first generation of hot massive stars and black-hole binaries filled the intergalactic medium with X-rays. 

“These X-rays would have heated up the hydrogen surrounding galaxies and should produce detectable fluctuations in the 21cm line,” said Jacqueline N Hewitt, lead investigator on the Moore Foundation grant, and director of the MIT Kavli Institute for Astrophysics and Space Research. “Measurements of the ‘Epoch of X-rays’ power spectrum could, in principle, distinguish between different scenarios for the very first generation of stars.”

Located at the South African Karoo Astronomy Reserve, HERA’s radio antennae use a low-frequency range of 50-250 MHz to detect fluctuations in emissions from neutral hydrogen gas found throughout the universe during the formation of stars, galaxies, and black holes. The array’s 14-meter dishes are sensitive to hydrogen at great distances, shifted downward in radio frequency by the expansion of the universe. The performance of the array will be enhanced by adding 110 antennae elements to the currently planned 240-antennae array and by extending its performance to lower radio frequencies.  

Work to begin adding the additional antennae to the array will begin in the summer of 2018, and collection of data with the full array is slated to begin about a year later.  NSF originally began supporting parallel efforts by U.S. teams to develop instrumentation to observe the EoR in the early 2000s, leading to a convergence of those teams to build HERA.  

This research is funded by the Gordon and Betty Moore Foundation. HERA received major grants from NSF's Mid-Scale Innovations Program in 2014 and 2016. The HERA collaboration consists of Arizona State University, Brown University, Cambridge University, MIT, the National Radio Astronomy Observatory, Scuola Normale Superiore (Pisa), the Square Kilometre Array Organization South Africa, the University of California at Berkeley, the University of California at Los Angeles, the University of Pennsylvania, and the University of Washington.

de MIT News http://ift.tt/2lF9wZ5

MIT’s Jacqueline Hewitt and HERA team given $6 millon boost to detect cosmic dawn

This week, the Hydrogen Epoch of Reionization Array (HERA) telescope project team was awarded a grant from the Gordon and Betty Moore Foundation to MIT to expand the HERA telescope in South Africa to begin looking for the effects of light from the first generation of stars that formed in the universe.

HERA, an international project led by researchers at the University of California at Berkeley, with initial funding from the National Science Foundation (NSF), is looking for signals from the “epoch of reionization” (EoR) when 90 percent of the hydrogen atoms created in the early universe were destroyed by the first luminous stars and black holes. The enhancement of the array, supported by the additional funding and carried out in partnership with MIT, the University of Virginia, and the National Radio Astronomy Observatory, will increase HERA's capability in several different ways.

“Expanding HERA will help us map bubbles of ionization around early galaxies in our universe and will extend our ability to find the earliest signs of star formation in our universe,” said Aaron Parsons, lead investigator on the HERA project and associate professor of astronomy at UC Berkeley, who noted the importance of collecting area and bandwidth for accessing a cosmological signal roughly 100,000 times fainter than emission from the Milky Way and nearby galaxies. 

With the grant from the Moore Foundation, the team can increase the sensitivity of the array and potentially detect signals coming from a time before the EoR in the history of the universe, the cosmic dawn, roughly 400 million years after the Big Bang. Using this next-generation in instrumentation for 21-cm cosmology — the wavelength of neutral hydrogen gas radio waves — HERA will probe the 3-D structure of the universe during the very first appearance of stars, galaxies, and black holes. This first generation of hot massive stars and black-hole binaries filled the intergalactic medium with X-rays. 

“These X-rays would have heated up the hydrogen surrounding galaxies and should produce detectable fluctuations in the 21cm line,” said Jacqueline N Hewitt, lead investigator on the Moore Foundation grant, and director of the MIT Kavli Institute for Astrophysics and Space Research. “Measurements of the ‘Epoch of X-rays’ power spectrum could, in principle, distinguish between different scenarios for the very first generation of stars.”

Located at the South African Karoo Astronomy Reserve, HERA’s radio antennae use a low-frequency range of 50-250 MHz to detect fluctuations in emissions from neutral hydrogen gas found throughout the universe during the formation of stars, galaxies, and black holes. The array’s 14-meter dishes are sensitive to hydrogen at great distances, shifted downward in radio frequency by the expansion of the universe. The performance of the array will be enhanced by adding 110 antennae elements to the currently planned 240-antennae array and by extending its performance to lower radio frequencies.  

Work to begin adding the additional antennae to the array will begin in the summer of 2018, and collection of data with the full array is slated to begin about a year later.  NSF originally began supporting parallel efforts by U.S. teams to develop instrumentation to observe the EoR in the early 2000s, leading to a convergence of those teams to build HERA.  

This research is funded by the Gordon and Betty Moore Foundation. HERA received major grants from NSF's Mid-Scale Innovations Program in 2014 and 2016. The HERA collaboration consists of Arizona State University, Brown University, Cambridge University, MIT, the National Radio Astronomy Observatory, Scuola Normale Superiore (Pisa), the Square Kilometre Array Organization South Africa, the University of California at Berkeley, the University of California at Los Angeles, the University of Pennsylvania, and the University of Washington.

de MIT News http://ift.tt/2mLMxMX

Global cement meeting paves the way for worldwide collaboration

Leaders of cement and concrete industry organizations from 11 countries and regions from around the U.S. met with researchers from the MIT Concrete Sustainability Hub (CSHub) in February to discuss cement and sustainability research and collaborate on opportunities to advance further research.

“Concrete plays a fundamental role in shaping modern life. Thanks to scientific and technological breakthroughs, it also is part of the solution when it comes to planning for more sustainable development,” said Jeremy Gregory, CSHub executive director and research scientist in the MIT Department of Civil and Environmental Engineering. “Events like this meeting ensure in the important research in this arena has the largest possible impact.”

Since its founding in 2009, the CSHub has been a leader in research designed to reduce the environmental impact of concrete both in its manufacturing and its use. Such work is vitally important because there is no other material on the planet that can replace concrete when it comes to meeting demands of our civilization for housing, business, transportation and infrastructure.

Work by the CSHub has always been collaborative — the CSHub itself is an interdisciplinary team of researchers from multiple departments across MIT, and the team’s work regularly brings together leaders from academia, industry, and government. The meeting gave the industry leaders an opportunity to present information about sustainability trends in their regions and countries, to learn about current work at the CSHub, and to see where there might be opportunities for cooperation.

Among the current projects discussed with attendees was one in which the CSHub has teamed up with researchers at Oregon State University (OSU) and the University of New Brunswick (UNB), Canada, to gain scientific understanding to improve the durability of concrete, including potential means to mitigate freeze-thaw and alkali-silica reaction (ASR). MIT is providing atomic and meso-scale modeling expertise and applications for the durability project, while OSU and UNB are contributing micro- and material macro-scale empirical expertise.

Gregory told the meeting attendees, “The interesting thing about the collaboration with OSU and UNB is that it was facilitated by our industry partners. Our partners knew that we had certain pieces to this puzzle and that the researchers at these other schools had some important pieces as well.”

The Portland Cement Association (PCA) convened the global meeting, and along with the Ready Mixed Concrete Research and Education Foundation, provides funding to the CSHub. With attendees hailing from Belgium, Columbia, Germany, Switzerland, the Netherlands, Australia, South Africa, China, India, and Canada, along with U.S. regions, the meeting represented a widening of the circle of leaders worldwide who can contribute to future research breakthroughs.

“We see the MIT CSHub as a hub of knowledge — a forum where the brightest minds from the academic world and private industry can connect to plan and conduct important industry research,” said James G. Toscas, PCA President and CEO. “This meeting was about inviting ideas and creating new connections on the international scale.”   

PCA is the primary policy, research, education, and market intelligence organization serving America’s cement manufacturers. PCA members represent 93 percent of U.S. cement production capacity and have facilities in all 50 states. The association promotes safety, sustainability, and innovation in all aspects of construction, fosters continuous improvement in cement manufacturing and distribution, and generally promotes economic growth and sound infrastructure investment.   

“As vocal advocates for sustainability, cement manufacturers are acutely aware of the role that concrete has had — and will continue to have — in building a resilient, sustainable world,” said Toscas. “We believe that the connections made during this meeting will result in research partnerships and revolutionary ideas that lead to even more durable and sustainable homes, buildings, and infrastructure across the globe.”

de MIT News http://ift.tt/2lzdIZt