Archive for Northwestern University
You are browsing the archives of Northwestern University.
You are browsing the archives of Northwestern University.
The Strategic Materials Advisory Council has cautioned the Department of Defense to avoid the risky mitigation strategy of stockpiling strategic and critical materials from China. The DOD recently completed its biannual “Strategic and Critical Materials 2013 Report on Stockpile Requirements,” which recommended stockpiling $120.43 million of heavy rare earth elements—materials produced only in China. ”The root cause of these material shortages is our ongoing dependence on Chinese suppliers,” says Council Executive Director Jeff Green. “While it is encouraging that DoD acknowledges these risks, we urge DOD to move from theoretical studies to the only appropriate and permanent solution: the creation and nurturing of a US-based rare earth supply chain.” The rare earth stockpile recommendation represents over one-third of a $319.74 million stockpiling plan to mitigate a $1.2 billion shortfall of 23 strategic and critical materials. This encouraging recommendation contrasts dramatically with previous DOD assessments that asserted domestic sources could meet all military requirements by 2013, except for yttrium, and that substitution would be a viable approach to risk mitigation for heavy rare earths.
A new chemotherapy drug in the form of nanoparticles is less toxic to young women’s fertility but extra tough on cancer, say researchers. “Our overall goal is to create smart drugs that kill the cancer but don’t cause sterility in young women,” says Teresa Woodruff, a co-principal investigator of the study and chief of fertility preservation at Northwestern University. The chemotherapy drug, arsenic trioxide, is packed into a very tiny Trojan horse called a nanobin. The nanobin consists of nano-size crystalline arsenic particles densely packed and encapsulated in a fat bubble. The fat bubble, a liposome, disguises the deadly cargo-half a million drug molecules. The fat bubble is the perfect size to stealthily slip through holes in the leaky blood vessels that rapidly grow to feed tumors. The local environment of the tumor is often slightly acid and it’s this acid that causes the nanobin to release its drug cargo and deliver a highly effective dose of arsenic where it is needed. The scientists show this approach to packaging and delivering the active drug has the desired effect on the tumor cells but prevents damage to ovarian tissue, follicles, or eggs. Arsenic trioxide was approved a few years ago for treating some types of blood cancers such as leukemia in humans, but the researchers think the arsenic trioxide nanobins can be used against breast cancer and other solid tumors.
At the Hannover trade fair, Fraunhofer researchers are now presenting a new manufacturing process with which these thermoelectric generators can be cost-effectively produced in the form of large-area flexible components from non-toxic synthetic materials. The scientists‘ vision is described by Aljoscha Roch of the Fraunhofer Institute for Material and Beam Technology IWS in Dresden: “Thermoelectric generators (TEG) currently have an efficiency of around eight percent. That sounds very small. But if we succeed in producing TEG cost-effectively, on a large scale and from flexible materials we can install them extensively on the insides of the concave cooling tower wall. In this way, through the enormous amount of energy produced in the huge plants—around 1500 liters of water evaporate per minute—we could generate large quantities of electricity.” The scientists have succeeded in producing TEGs by means of a printing process. The miniaturized generators can not only be produced cost-effectively, on large surfaces and in a flexibly manageable manner, but an additional major advantage is that the materials used are environmentally-friendly. “TEG are today largely produced by hand from toxic components which contain lead for example. We are now using modern 3D printing technology and harmless polymers (plastics) that are electrically conductive,” explains Roch. The IWS researchers are demonstrating the printed TEG for the first time in a cooling tower model at the Hannover trade fair.
Researchers have developed a “hyperbolic metamaterial waveguide” that halts and ultimately absorbs each frequency of light, at slightly different places in a vertical direction, to catch a “rainbow” of wavelengths. The technology is essentially an advanced microchip made of ultrathin films of metal and semiconductors and/or insulators. ”Right now, researchers are developing compact light absorbers based on optically thick semiconductors or carbon nanotubes. However, it is still challenging to realize the perfect absorber in ultrathin films with tunable absorption band,” says Qiaoqiang Gan, an assistant professor of electrical engineering at University at Buffalo. Gan previously helped pioneer a way to slow light without cryogenic gases. He and other researchers at Lehigh University made nanoscale-sized grooves in metallic surfaces at different depths, a process that altered the optical properties of the metal. While the grooves worked, they had limitations. For example, the energy of the incident light cannot be transferred onto the metal surface efficiently, which hampered its use for practical applications. As reported in the journal Scientific Reports, the waveguide solves that problem because it is a large area of patterned film that can collect the incident light efficiently. Researchers say the technology could lead to advancements in an array of fields, such as preventing crosstalk in electronics or energy-harvesting devices.
The High-Pressure Collaborative Access Team (HPCAT), a group linked to the Advanced Photon Source (APS) facility at the Argonne National Lab, held a workshop Oct. 10-12, 2012, to review the successes of HPCAT over the past 10 years, as well as opportunities for addressing key grand challenges in future of extreme conditions science. During the past decade, HPCAT has taken advantage of the nation’s most brilliant high-energy synchrotron source and developed a multitude of integrated synchrotron radiation techniques optimized for high-pressure research. These X-ray probes, integrated with hydrostatic or uniaxial compression, static or dynamic loading, resistive or laser heating, and cryogenic cooling, have enabled users’ investigations of structural, vibrational, electronic, and magnetic properties at high pressure and high/low temperature that were not possible a decade ago. The workshop consisted of over 120 people from the US and abroad. Emerging from the workshop and its discussions is a clear signal of the outstanding opportunities for the future of extreme conditions science at the APS in the years to come. The report is approximately 120 pages (pdf)
New experiments set the record of the superconducting transition temperatures for a new family of iron-based selenide superconductors. These materials were recently found to superconduct below 30 K, but their transition temperatures decline until approaching absolute zero temperature with the application of pressure. Now Carnegie scientists Xiao-Jia Chen, Lin Wang, and Ho-Kwang Mao, in collaboration with scientists from from the National Institute of Standards and Technology, the Chinese Academy of Science, and Zhejiang University, have uncovered reemerging superconductivity above 48 K in iron selenides upon further compression. The disappearance of superconductivity in the low-pressure cycle and the re-emergence of superconductivity with higher transition temperatures in the high-pressure cycle reflect detailed structural variances within the basic unit cell itself. The two superconducting domes were likely the result of different charge carriers. Finding the reentrance of superconductivity at 48 K in the new iron family of superconductors points to the possibility of achieving similar higher transition temperatures at ambient pressure through some structural modifications
New research carried out at MIT and elsewhere has demonstrated for the first time that when inserted into a pool of liquid, nanowires - wires that are only hundreds of nanometers across - naturally draw the liquid upward in a thin film that coats the surface of the wire. The finding could have applications in microfluidic devices, biomedical research and inkjet printers. Although this upward pull is always present with wires at this tiny scale, the effect can be further enhanced in various ways: Adding an electric voltage on the wire increases the force, as does a slight change in the profile of the wire so that it tapers toward one end. The researchers used nanowires made of different materials—silicon, zinc oxide and tin oxide, as well as two-dimensional graphene—to demonstrate that this process applies to many different materials. The results are published in the journal Nature Nanotechnology by a team of researchers led by Ju Li, an MIT professor of nuclear science and engineering and materials science and engineering, along with researchers at Sandia National Laboratories in New Mexico, the University of Pennsylvania, the University of Pittsburgh, and Zhejiang University in China. Several brief videos of the nanowires in action have been posted on YouTube by Li’s research group.
Even graphene, the Superman of materials, has its kryptonite: Defects in polycrystalline graphene will sap its strength. The unexpected weakness is in the form of a seven-atom ring that inevitably occurs at the junctions of grain boundaries in graphene, where the regular array of hexagonal units is interrupted, report researchers. At these points, under tension, polycrystalline graphene has about half the strength of pristine samples of the material. New research shows defects in polycrystalline forms of graphene will sap its strength. The new calculations could be important to materials scientists using graphene in applications where its intrinsic strength is a key feature, like composite materials and stretchable or flexible electronics. The team calculated that the particular seven-atom rings found at junctions of three islands are the weakest points, where cracks are most likely to form. These are the end points of grain boundaries between the islands and are ongoing trouble spots.
(Updated) A few days ago I posted a story and video to introduce ACerS’s new Art, Archaeology and Conservation Science Division. The video features Katherine Faber, who teaches and engages in materials science and engineering research at Northwestern University. Faber, the trustee of the new Division, has been involved with art conservation science for many years, and this work just has been rewarded. Just recently, it was announced that Faber and colleagues connected with Chicago Art Institute will establish an entirely new, multimillion-dollar institute dedicated to interdisciplinary research among scientists, conservators, and curators.
The new institute—to be called NU-ACCESS (the Northwestern University—Art Institute of Chicago Center for Scientific Studies in the Arts—is being made possible by a $2.5 million, six-year grant from the Mellon Foundation, a group that has been supporting this type of work for several years.
NU-ACCESS, the first of its type in the United States, is the direct fruit of the work of Faber and Francesca Casadio, the Andrew W. Mellon Senior Conservation Scientist at the Chicago Art Institute, who teamed up with her in 2004 to launched an ad hoc museum–Northwestern University partnership. The new grant will allow Faber and Casadio to expand and institutionalize the partnership. According to a Northwestern University press release, the new center will “serve as a collaborative hub, facilitating interdisciplinary research partnerships in art studies and conservation on a national scale. Academic researchers and scholars in training will meet and engage in mutual learning.”
The release also recounts how partnership’s remarkable discoveries over the years have been woven into major exhibitions at the Art Institute, including exhibitions of the works by Matisse and Winslow Homer. An upcoming show, “Picasso and Chicago,” will include findings from a study of modern bronze sculptures in which Northwestern and museum researchers traced some of Picasso’s unmarked sculptures to the Valsuani foundry in Paris, based on materials evidence.
Faber and Casadio also showcased several of the partnerships efforts as part of a tour of the museum held during the 2012 International Congress on Ceramics held last July (see photo, above).
“Art and technology are prime material evidence of humanity’s accomplishment,” Casadio says in the press release. “By bringing the two together in this center, we will have a chance to enhance our understanding of the world’s shared cultural objects and preserve them for future generations. This landmark initiative represents a tectonic shift from the isolated museum scientist to a dynamic hub that will serve as incubator of new ideas and significantly accelerate the rate of discoveries by providing the latest technological innovations brewing in the academic environment,” says Casadio.
NU-ACCESS will be located at NU, and will eventually be staffed by a senior scientist and two postdoctoral fellows. The concept is that museums and other cultural institutions will submit research proposals to CSSA to investigate objects in their collection, or investigate scientific issues raised by those objects.
“As the first such initiative in the United States, the center will inspire a new model for research partnerships between museums and academia, and we are especially excited by the promise of bringing museum professionals, researchers and students together to contribute original and groundbreaking research to their respective fields,” says Douglas Druick, president of the Art Institute, also in the press release.
An example of the type of work the NU-ACCESS will engage in is contained in a new paper by Casadio and coauthor Volker Rose, a physicist at the Argonne National Lab, published in Applied Physics A (doi:10.1007/s00339-012-7534-x) that for the first time documents that Pablo Picasso eventually employed common house paint in many of his works, such as his The Red Chair painting on display in the Art Institute. Casadio and Rose used ANL’s hard X-ray nanoprobe, an instrument at the Advanced Photon Source facility located at the lab. According to a new ANL press release, the X-ray nanoprobe “is designed to advance the development of high-performance materials and sustainable energies by giving scientists a close-up view of the type and arrangement of chemical elements in material.”
Investigators had previously used optical and electron microscopy to resolve the mystery of Picasso’s paints, but had failed. According to the ANL release, “Those art world detectives all failed, because traditional tools wouldn’t let them see deeply enough into the layers of paint or with enough resolution to distinguish between store-bought enamel paint and techniques designed to mimic its appearance.” Using the X-ray nanoprobe, Casadio and Rose were able to match Picasso’s paints to the chemical composition, particularly in regard to zinc oxide, of one of the first brands of commercial enamel house paints (Ripolin).
The benefits of this work apparently don’t accrue just in the art world. The ANL release also notes that in the course of doing this work, “Scientists also learned about the correlation of the spacing of impurities at the nanoscale in zinc oxide, offering important clues to how zinc oxide could be modified to improve performance in a variety of products, including sensors for radiation detection, LEDs and energy-saving windows, as well as liquid-crystal displays for computers, TVs, and instrument panels.”
With the election behind it, the Obama administration appears to be quickly returning to a major emphasis on energy and “materials genome” related research.
First, according to a new story coauthored by Cyrus Wadia, the Office of Science and Technology Policy’s point person for the Materials Genome Initiative, $25 million worth of grants recently announced by NSF and DOE will directly impact the initiative and are “a significant milestone” for the project.
Wadia, and coauthor Meredith Drosback, a TMS fellow at OSTP, highlight seven particular MGI-related projects that received the new awards:
• A new Lawrence Berkeley National Laboratory/MIT software center focused on computer simulations to rapidly prototype lithium ion battery electrolyte candidates;
• A University of Washington/GM collaboration to model thermoelectric materials to add efficiencies to next-gen auto engines;
• A University of Michigan center to create a suite of software tools to predict the behavior of magnesium alloys in lightweight vehicles;
• A University of Minnesota center to develop computer algorithms for the design of porous materials aimed at delivering advanced utility-scale carbon capture and sequestration technologies;
• A collaboration between the Universities of Pennsylvania and Delaware to create models to predict and assemble efficient and low-cost solar energy biomaterials;
• A project by researchers from University of Virginia and University of Alabama Tuscaloosa that will model, synthesize, and test new materials to be incorporated into circuits for faster computer memory;
• A research network between University of Illinois and Oak Ridge, Sandia, Argonne and Lawrence Livermore National Labs to develop computer code to better predict the behavior and performance of catalysts, semiconductor and related materials.
We will be working on providing more links to these projects. In the meantime, we are also working on an a related story for next week about the new report on the results of a NIST workshop held in May on the topic of Building the Materials Innovation Infrastructure: Data and Standards.
Also, the administration announced today that it is investing $120 million over the next five years in a new Joint Center for Energy Storage Research that will be led by Argonne National Lab. JCESR also will involve several universities, other federal labs and a handful of private sector partners. Participants include Lawrence Berkeley National Lab, Pacific Northwest National Lab, Sandia National Labs, SLAC National Accelerator Lab, Northwestern University, University of Chicago, University of Illinois-Chicago, University of Illinois-Urbana Champaign, University of Michigan, Dow Chemical, Applied Materials, Johnson Controls and Clean Energy Trust.
According to a DOE news release, JCESR will focus on “advancements in batteries and energy storage technology are essential for continued efforts to develop a fundamentally new energy economy with decisively reduced dependence on imported oil. Improved storage will be vital to fully integrating intermittent renewable energy sources such as wind and solar into the electrical grid. It will also be critical to transitioning the transportation sector to more flexible grid power.” The hub, formerly known as the Batteries and Energy Storage Hub, is supposed to address
• Efficacy of materials architectures and structure in energy storage;
• Charge transfer and transport;
• Multi-scale modeling; and
• Probes of energy storage chemistry and physics at all time and length scales.
JCESR is DOE’s fourth Energy Innovation Hub. DOE is planning a fifth hub dedicated to “critical materials” research. The agency is still accepting and evaluating proposals for this hub.
There were several pre-MS&T’12 events over the weekend before the mega-meeting’s official reception Sunday night, including the start of The American Ceramic Society’s Annual Meeting, a roundtable meeting of the Society’s division leaders, division executive committee meetings, several student-based activities and the Frontiers of Science and Society—Rustum Roy Reception and Lecture.
Here are what some of the events looked like:
Some developments worth reading about:
Though the concept of high temperature superconductors is more than two decades old, finding and controlling the right materials has been a challenge. Now Yoram Dagan of Tel Aviv University’s Department of Physics and Center for Nanoscience and Nanotechnology has discovered an innovative way to manipulate superconducting materials. By manipulating different types of light, including UV and visible light, Dagan and his fellow researchers are able to alter the critical temperatures of superconducting materials. This finding adds to a growing toolbox for controlling and improving the technology. The research has been published in Angewandte Chemie and featured in Nature Nanotechnology. In the lab, they put a thin layer, one organic molecule thick, atop a superconducting film, approximately 50 nanometers thick. When researchers shined a light on these molecules, the molecules stretched and changed shape, altering the properties of the superconducting film-most importantly, altering the critical temperature at which the material acted as a superconductor. The researchers tested three separate molecules. The first was able to increase the critical temperature of the superconducting film. With the second molecule, they found that shining an ultraviolet light heightened the material’s critical temperature, while visible light lowered it. Finally, with the third molecule, they found that simply by turning a light on, critical temperature was raised-and lowered again when the light was switched off.
Researchers have created a new type of biosensor that can detect minute concentrations of glucose in saliva, tears and urine and might be manufactured at low cost because it does not require many processing steps to produce. “Most sensors typically measure glucose in blood,” says Jonathan Claussen, a former Purdue University doctoral student and now a research scientist at the Naval Research Laboratory. “Many in the literature aren’t able to detect glucose in tears and the saliva. What’s unique is that we can sense in all four different human serums: the saliva, blood, tears and urine. And that hasn’t been shown before.” The sensor has three main parts: layers of graphene nanosheets resembling tiny rose petals; platinum nanoparticles; and the enzyme glucose oxidase. Each petal contains a few layers of stacked graphene. The edges of the petals have dangling, incomplete chemical bonds, defects where platinum nanoparticles can attach. Electrodes are formed by combining the nanosheet petals and platinum nanoparticles. Then the glucose oxidase attaches to the platinum nanoparticles. The enzyme converts glucose to peroxide, which generates a signal on the electrode. “The good thing about these petals is that they can be grown on just about any surface, and we don’t need to use any of these steps, so it could be ideal for commercialization,” says Purdue doctoral student Anurag Kumar.
Fueling nuclear reactors with uranium harvested from the ocean could become more feasible because of a material developed by a team led by the DOE’s Oak Ridge National Lab. The combination of ORNL’s high-capacity reusable adsorbents and a Florida company’s high-surface-area polyethylene fibers creates a material that can rapidly, selectively and economically extract valuable and precious dissolved metals from water. The material, HiCap, vastly outperforms today’s best adsorbents, which perform surface retention of solid or gas molecules, atoms or ions. HiCap also effectively removes toxic metals from water, according to results verified by researchers at Pacific Northwest National Lab. “We have shown that our adsorbents can extract five- to seven-times more uranium at uptake rates seven-times faster than the world’s best adsorbents,” says Chris Janke, one of the inventors and a member of ORNL’s Materials Science and Technology Division. ”Our HiCap adsorbents are made by subjecting high-surface area polyethylene fibers to ionizing radiation, then reacting these pre-irradiated fibers with chemical compounds that have a high affinity for selected metals.” After the processing, scientists can place HiCap adsorbents in water containing the targeted material, which is quickly and preferentially trapped. Scientists then remove the adsorbents from the water and the metals are readily extracted using a simple acid elution method. The adsorbent can then be regenerated and reused after being conditioned with potassium hydroxide. Results were presented today at the fall meeting of the American Chemical Society in Philadelphia.
(EE Times) MC10, a Cambridge, Mass., startup specializing in flexible electronics, has signed a one year contract with the Army to develop and test solar cell technology for military use. The technology will take the form of wearable solar panels built into military personnel’s clothing to power up America’s GIs, while decreasing the number of battery packs lugged around. MC10 specializes in re-engineering rigid electronics into flexible forms and has made significant strides in creating human vital stat sensors which have been successfully applied to surgical patients and athletes alike. The sensors are typically a 1-inch flexible patch that tracks temperature, heart rate and hydration. For the necessary flexibility required for solar powered clothing, MC10 uses flexible microgrids of solar cells, connected by gold ribbon wrapped in a soft conducting polymer. The wearable solar cells harness the power of gallium arsenide, the light harvesting metal compound built into high-efficiency solar panels found on rooftops.
A new class of organic materials developed at Northwestern University boasts a very attractive but elusive property: ferroelectricity. The crystalline materials also have a great memory, which could be very useful in computer and cellphone memory applications, including cloud computing. A team of organic chemists discovered they could create very long crystals with desirable properties using just two small organic molecules that are extremely attracted to each other. The attraction between the two molecules causes them to self assemble into an ordered network, order that is needed for a material to be ferroelectric. The starting compounds are simple and inexpensive, making the lightweight materials scalable and very promising for technology applications. In contrast, conventional ferroelectric materials—special varieties of polymers and ceramics—are complex and expensive to produce. The Northwestern materials can be made quickly and are very versatile. The study is published in the journal Nature. These new supramolecular materials derive their properties from the specific interaction, repeated over and over again between two small alternating organic molecules, not from the molecules themselves. The two complementary molecules interact electronically and so strongly that they come close together and form very long crystals. This highly ordered 3D network is based on hydrogen bonds.
A team of scientists led by Carnegie Institution for Science’s Lin Wang has observed a new form of very hard carbon clusters, which are unusual in their mix of crystalline and disordered structure. The material is capable of indenting diamond. This finding has potential applications for a range of mechanical, electronic, and electrochemical uses. The work is published in Science. Wang’s team started with carbon-60 cages. An organic xylene solvent was put into the spaces between the balls and formed a new structure. They then applied pressure to this combination of carbon cages and solvent, to see how it changed under different stresses. At relatively low pressure, the carbon-60’s cage structure remained. But, as the pressure increased, the cage structures started to collapse into more amorphous carbon clusters. However, the amorphous clusters still occupy their original sites, forming a lattice structure. The team discovered that there is a narrow window of pressure, about 320,000 times the normal atmosphere, under which this new structured carbon is created and does not bounce back to the cage structure when pressure is removed. This material was capable of indenting the diamond anvil used in creating the high-pressure conditions. If the solvent used to prepare the new form of carbon is removed by heat treatment, the material loses its lattice periodicity, indicating that the solvent is crucial for maintaining the chemical transition that underlies the new structure. Because there are many similar solvents, it is theoretically possible that an array of similar, but slightly different, carbon lattices could be created using this pressure method.