Tagged: Material Sciences Toggle Comment Threads | Keyboard Shortcuts

  • richardmitnick 2:52 pm on October 8, 2017 Permalink | Reply
    Tags: , , , , , Material Sciences, NAE-National Academy of Engineering, ,   

    From Wyss: Women in STEM: “Jennifer Lewis elected to National Academy of Engineering” 

    Harvard bloc tiny
    Wyss Institute bloc
    Wyss Institute

    February 9, 2017 [Egad!! I guess this was really important to Wyss. This neglect is more like Rutgers]
    Leah Burrows

    1

    Jennifer A. Lewis, a Core Faculty member of the Wyss Institute of Biologically Inspired Engineering and the Hansjörg Wyss Professor of Biologically Inspired Engineering at the Harvard John A. Paulson School of Engineering and Applied Sciences has been elected to the National Academy of Engineering (NAE).

    Lewis’ research focuses on the design and fabrication of functional, structural and biological materials. Her pioneering work in the field of microscale 3D printing is advancing the development of electronics, soft robotics, lightweight structures, and vascularized human tissues.

    Lewis is an inventor on more than 40 pending or issued patents and founded the startup company Voxel8, Inc., to commercialize the first multi-material 3D printing for the fabrication of embedded electronics.

    She is among 84 new members elected to the NAE, chosen for their outstanding contributions to engineering research, practice, or education and their pioneering work into new and developing fields of technology. Lewis is being honored for her “development of materials and processes for 3-dimensional direct fabrication of multifunctional structures.”

    Lewis earned a Sc.D. in Ceramic Science from the Massachusetts Institute of Technology. Her many honors include the NSF Presidential Faculty Fellow Award, the Brunauer and Sosman Awards from the American Ceramic Society, the Langmuir Lecture Award from the American Chemical Society and the Materials Research Society Medal. She is a Fellow of the American Ceramic Society, the American Physical Society, the Materials Research Society, the National Academy of Inventors and the American Academy of Arts and Sciences.

    Individuals in the newly elected class will be formally inducted during a ceremony at the NAE’s annual meeting in Washington, D.C., on Oct. 8, 2017.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    Wyss Institute campus

    The Wyss (pronounced “Veese”) Institute for Biologically Inspired Engineering uses Nature’s design principles to develop bioinspired materials and devices that will transform medicine and create a more sustainable world.

    Working as an alliance among Harvard’s Schools of Medicine, Engineering, and Arts & Sciences, and in partnership with Beth Israel Deaconess Medical Center, Boston Children’s Hospital, Brigham and Women’s Hospital, Dana Farber Cancer Institute, Massachusetts General Hospital, the University of Massachusetts Medical School, Spaulding Rehabilitation Hospital, Tufts University, and Boston University, the Institute crosses disciplinary and institutional barriers to engage in high-risk research that leads to transformative technological breakthroughs.

    Advertisements
     
  • richardmitnick 10:45 am on September 28, 2017 Permalink | Reply
    Tags: "DLR and JAXA and AIST sign cooperation in energy research, , , , Faster development based on international standards for thermoelectric generators, Material Sciences, More durable batteries for space missions,   

    From DLR: “DLR, JAXA and AIST sign cooperation in energy research” 

    DLR Bloc

    German Aerospace Center

    22 September 2017

    Contacts

    Dorothee Bürkle
    German Aerospace Center (DLR)
    Media Relations, Energy and Transport Research
    Tel.: +49 2203 601-3492
    Fax: +49 2203 601-3249

    Dr. Niklas Reinke
    Deutsches Zentrum für Luft- und Raumfahrt (DLR) – German Aerospace Center
    Tel.: +49 228 447-394
    Fax: +49 228 447-386

    Prof. Dr. Arnulf Latz
    German Aerospace Center (DLR)
    DLR Institute of Engineering Thermodynamics
    Tel.: +49 731 5034084

    Pawel Ziolkowski
    German Aerospace Center (DLR)
    Thermoelectric Materials and Systems
    Tel.: +49 22 036013-576

    Martin Kober
    German Aerospace Center (DLR)
    Institute of Vehicle Concepts, Alternative Energy Converters
    Tel.: +49 711 6862-457

    Dr Thorsten Nix
    German Aerospace Center (DLR)
    International Cooperation
    Tel.: +49 2203 601-2177

    1

    2

    3

    The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), the Japanese space agency, JAXA, and the Nationale Institute of Advanced Industrial Science and Technology in Japan (AIST) signed two cooperation agreements on 21 September 2017 in Tokyo. The research institutes will collaborate in future on the development of high-performance and durable batteries for space missions. The scientists will also conduct research to develop thermoelectric generators, as well as standards to measure the efficiency of their performance.

    “In AIST and JAXA, DLR has found two research institutes that are highly regarded on the international stage and with whom it can explore extremely topical issues of batteries and thermoelectric energy generators. This opens up many opportunities to pool competencies and will likely produce rapid progress in joint developments,” said Pascale Ehrenfreund, Chair of the DLR Executive Board, during the signing of the cooperation agreements in Tokyo.

    More durable batteries for space missions

    In the coming years, the Department of Computational Electrochemistry at the DLR Institute of Engineering Thermodynamics will collaborate with Japanese researchers on the development of high-performance and durable batteries for space missions. Among other things, their research in this field will focus on the Japanese satellite mission REIMEI. This satellite was equipped with one of the first modern lithium-ion batteries that has been operating for over 10 years already in space and will continue to do so for several years. Data on its battery performance has been collected since REIMEI’s launch. This unique database will allow the DLR scientists to continue optimising their highly precise battery simulation. The aim is to develop a simulation method and to acquire data with which the battery condition can be predicted and influenced exactly.

    The Department of Computational Electrochemistry is among the world’s leading research facilities that is able to investigate and create 3D simulations of the processes at play inside a battery down to the microscale of the electrode structure. The researchers are therefore in a position to detect signs of ageing and fatigue and to identify their causes. The cycle life of the battery can be increased by means of improved design and optimised charging and discharging cycles. The research is highly relevant for electromobility and terrestrial applications as well, given the spiralling importance of batteries as energy storage units. This cooperation with AIST and JAXA is an outstanding opportunity to deploy the competencies and resources of the participating institutions in a more targeted form.

    Faster development based on international standards for thermoelectric generators

    Thermoelectric generators (TEGs) convert waste heat from combustion processes into electrical energy. They can be used to increase energy efficiency in automobiles, aircraft and in stationary applications, and are suitable as independent, mobile electricity sources as well. In automobiles, for instance, converting the waste heat in exhaust fumes into electrical energy for the vehicle is expected to reduce fuel consumption by up to five percent. Laboratories worldwide are creating increasingly efficient modules – a precondition for the development of many new applications. In addition to solutions for industrial integration, another requirement for smooth transfer into the practical arena is the definition of standardised measurement procedures to determine the efficiency and performance of the TEG modules, which so far has not been done either at a national or international level. Measurement uncertainties of more than 15 percent continue to occur regularly with current measurement techniques. This is inadequate for scientific investigations and industrial developments and is delaying the market penetration of thermoelectric systems across all areas of application. Joint performance of more realistic testing will narrow the gap to the successful roll-out of a technology that has the potential to significantly reduce emissions and greenhouse gases, for instance in passenger and freight transport.

    In future, the DLR Institute of Materials Research, the Institute of Vehicle Concepts and AIST will work on precise measurement procedures to obtain more meaningful measurement results. First, this will advance standardisation of these methods to enable reproducible and comparable findings that are in line with scientific requirements. Second, the thermoelectric generators will be measured more realistically when integrated into a motor vehicle and their efficiency can thus be improved. Intense research of thermoelectric materials and systems is currently ongoing in Japan and in Germany – both by the scientific community and in industry. Defined standards should enable the faster developments of TEGs in future. The partners will therefore be able to offer crucial support to manufacturers of thermoelectric generators and measurement systems in the market introduction of their products.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    DLR Center

    DLR is the national aeronautics and space research centre of the Federal Republic of Germany. Its extensive research and development work in aeronautics, space, energy, transport and security is integrated into national and international cooperative ventures. In addition to its own research, as Germany’s space agency, DLR has been given responsibility by the federal government for the planning and implementation of the German space programme. DLR is also the umbrella organisation for the nation’s largest project management agency.

    DLR has approximately 8000 employees at 16 locations in Germany: Cologne (headquarters), Augsburg, Berlin, Bonn, Braunschweig, Bremen, Goettingen, Hamburg, Juelich, Lampoldshausen, Neustrelitz, Oberpfaffenhofen, Stade, Stuttgart, Trauen, and Weilheim. DLR also has offices in Brussels, Paris, Tokyo and Washington D.C.

     
  • richardmitnick 8:03 am on September 1, 2017 Permalink | Reply
    Tags: , Material Sciences, Nanocrystals rapidly forming superlattices while they are themselves still growing, , , Scientists Watch ‘Artificial Atoms’ Assemble into Perfect Lattices with Many Uses, , Superlattices can form superfast   

    From SLAC: “Scientists Watch ‘Artificial Atoms’ Assemble into Perfect Lattices with Many Uses” 


    SLAC Lab

    July 31, 2017
    Andrew Gordon
    agordon@slac.stanford.edu
    (650) 926-2282
    Written by Glennda Chui

    1
    An illustration shows nanocrystals assembling into an ordered ‘superlattice’ – a process that a SLAC/Stanford team was able to observe in real time with X-rays from the Stanford Synchrotron Radiation Lightsource (SSRL). They discovered that this assembly takes just a few seconds when carried out in hot solutions. The results open the door for rapid self-assembly of nanocrystal building blocks into complex structures with applications in optoelectronics, solar cells, catalysis and magnetic materials. (Greg Stewart/SLAC National Accelerator Laboratory)

    A serendipitous discovery lets researchers spy on this self-assembly process for the first time with SLAC’s X-ray synchrotron. What they learn will help them fine-tune precision materials for electronics, catalysis and more.

    Some of the world’s tiniest crystals are known as “artificial atoms” because they can organize themselves into structures that look like molecules, including “superlattices” that are potential building blocks for novel materials.

    Now scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have made the first observation of these nanocrystals rapidly forming superlattices while they are themselves still growing. What they learn will help scientists fine-tune the assembly process and adapt it to make new types of materials for things like magnetic storage, solar cells, optoelectronics and catalysts that speed chemical reactions.

    The key to making it work was the serendipitous discovery that superlattices can form superfast – in seconds rather than the usual hours or days – during the routine synthesis of nanocrystals. The scientists used a powerful beam of X-rays at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) to observe the growth of nanocrystals and the rapid formation of superlattices in real time.

    SLAC/SSRL

    A paper describing the research, which was done in collaboration with scientists at the DOE’s Argonne National Laboratory, was published today in Nature.

    “The idea is to see if we can get an independent understanding of how these superlattices grow so we can make them more uniform and control their properties,” said Chris Tassone, a staff scientist at SSRL who led the study with Matteo Cargnello, assistant professor of chemical engineering at Stanford.

    Tiny Crystals with Outsized Properties

    2
    Stanford Assistant Professor Matteo Cargnello at a lab in the Stanford Chemical Engineering Department where nanocrystals are grown. Cargnello and Chris Tassone, a staff scientist at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL), led a team that discovered how superlattices can grow unexpectedly fast – in seconds, rather than hours or days – during routine nanocrystal synthesis. (Dawn Harmer/SLAC National Accelerator Laboratory)

    Scientists have been making nanocrystals in the lab since the 1980s. Because of their tiny size –they’re billionths of a meter wide and contain just 100 to 10,000 atoms apiece — they are governed by the laws of quantum mechanics, and this gives them interesting properties that can be changed by varying their size, shape and composition. For instance, spherical nanocrystals known as quantum dots, which are made of semiconducting materials, glow in colors that depend on their size; they are used in biological imaging and most recently in high-definition TV displays.

    In the early 1990s, researchers started using nanocrystals to build superlattices, which have the ordered structure of regular crystals, but with small particles in place of individual atoms. These, too, are expected to have unusual properties that are more than the sum of their parts.

    But until now, superlattices have been grown slowly at low temperatures, sometimes in a matter of days.

    That changed in February 2016, when Stanford postdoctoral researcher Liheng Wu serendipitously discovered that the process can occur much faster than scientists had thought.

    3
    The experimental set-up at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) where scientists used an X-ray beam to observe superlattices forming during the synthesis of nanocrystals for the first time. The vessel where the reactions took place is at bottom center, wrapped in gold heating tape that boosted the temperature inside to more than 230 degrees Celsius. (Liheng Wu/Stanford University)

    ‘Something Weird Is Happening’

    He was trying to make nanocrystals of palladium – a silvery metal that’s used to promote chemical reactions in catalytic converters and many industrial processes – by heating a solution containing palladium atoms to more than 230 degrees Celsius. The goal was to understand how these tiny particles form, so their size and other properties could be more easily adjusted.

    The team added small windows to a reaction chamber about the size of a tangerine so they could shine an SSRL X-ray beam through it and watch what was happening in real time.

    “It’s kind of like cooking,” Cargnello explained. “The reaction chamber is like a pan. We add a solvent, which is like the frying oil; the main ingredients for the nanocrystals, such as palladium; and condiments, which in this case are surfactant compounds that tune the reaction conditions so you can control the size and composition of the particles. Once you add everything to the pan, you heat it up and fry your stuff.”

    Wu and Stanford graduate student Joshua Willis expected to see the characteristic pattern made by X-rays scattering off the tiny particles. They saw a completely different pattern instead.

    “So something weird is happening,” they texted their adviser.

    The something weird was that the palladium nanocrystals were assembling into superlattices.

    A Balance of Forces

    At this point, “The challenge was to understand what brings the particles together and attracts them to each other but not too strongly, so they have room to wiggle around and settle into an ordered position,” said Jian Qin, an assistant professor of chemical engineering at Stanford who performed theoretical calculations to better understand the self-assembly process.

    Once the nanocrystals form, what seems to be happening is that they acquire a sort of hairy coating of surfactant molecules. The nanocrystals glom together, attracted by weak forces between their cores, and then a finely tuned balance of attractive and repulsive forces between the dangling surfactant molecules holds them in just the right configuration for the superlattice to grow.

    To the scientists’ surprise, the individual nanocrystals then kept on growing, along with the superlattices, until all the chemical ingredients in the solution were used up, and this unexpected added growth made the material swell. The researchers said they think this occurs in a wide range of nanocrystal systems, but had never been seen because there was no way to observe it in real time before the team’s experiments at SSRL.

    “Once we understood this system, we realized this process may be more general than we initially thought,” Wu said. “We have demonstrated that it’s not only limited to metals, but it can also be extended to semiconducting materials and very likely to a much larger set of materials.”

    The team has been doing follow-up experiments to find out more about how the superlattices grow and how they can tweak the size, composition and properties of the finished product.

    Ian Salmon McKay, a graduate student in chemical engineering at Stanford, and Benjamin T. Diroll, a postdoctoral researcher at Argonne National Laboratory’s Center for Nanoscale Materials (CNM), also contributed to the work.

    SSRL and CNM are DOE Office of Science User Facilities. The research was funded by the DOE Office of Science and by a Laboratory Directed Research and Development grant from SLAC.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
    i1

     
  • richardmitnick 5:31 pm on July 20, 2017 Permalink | Reply
    Tags: , , If all the states in a group of bands are filled with electrons then the electrons cannot move and the material is an insulator, Material Sciences, , , The approach combined tools from such disparate fields as chemistry and mathematics also physics and materials science, The nearly century-old band theory of solids considered one of the early landmark achievements of quantum mechanics, The research shows that symmetry and topology also chemistry and physics all have a fundamental role to play in our understanding of materials, The theory describes the electrons in crystals as residing in specific energy levels known as bands,   

    From Princeton: “Researchers find path to discovering new topological materials, holding promise for technological applications” 

    Princeton University
    Princeton University

    July 20, 2017
    No writer credit

    1
    Researchers have discovered how to identify new examples of topological materials, which have unique and desirable electronic properties. The technique involves finding the connection between band theory, which describes the energy levels of electrons in a solid, with a material’s topological nature. The disconnected bands indicate the material is a topological insulator. Image courtesy of Nature.

    Researchers find path to discovering new topological materials, holding promise for technological applications.

    An international team of researchers has found a way to determine whether a crystal is a topological insulator — and to predict crystal structures and chemical compositions in which new ones can arise. The results, published July 20 in the journal Nature, show that topological insulators are much more common in nature than currently believed.

    Topological materials, which hold promise for a wide range of technological applications due to their exotic electronic properties, have attracted a great deal of theoretical and experimental interest over the past decade, culminating in the 2016 Nobel Prize in physics. The materials’ electronic properties include the ability of current to flow without resistance and to respond in unconventional ways to electric and magnetic fields.

    Until now, however, the discovery of new topological materials occurred mainly by trial and error. The new approach described this week [see above reference to the Nature article] allows researchers to identify a large series of potential new topological insulators. The research represents a fundamental advance in the physics of topological materials and changes the way topological properties are understood.

    The team included: at Princeton University, Barry Bradlyn and Jennifer Cano, both associate research scholars at the Princeton Center for Theoretical Science, Zhijun Wang, a postdoctoral research associate, and B. Andrei Bernevig, professor of physics; professors Luis Elcoro and Mois Aroyo at the University of the Basque Country in Bilbao; assistant professor Maia Garcia Vergniory of University of the Basque Country and Donostia International Physics Center (DIPC) in Spain; and Claudia Felser, professor at the Max Planck Institute for Chemical Physics of Solids in Germany.

    “Our approach allows for a much easier way to find topological materials, avoiding the need for detailed calculations,” Felser said. “For some special lattices, we can say that, regardless of whether a material is an insulator or a metal, something topological will be going on,” Bradlyn added.

    Until now, of the roughly 200,000 materials catalogued in materials databases, only around a few hundred are known to host topological behavior, according to the researchers. “This raised the question for the team: Are topological materials really that scarce, or does this merely reflect an incomplete understanding of solids?” Cano said.

    To find out, the researchers turned to the nearly century-old band theory of solids, considered one of the early landmark achievements of quantum mechanics. Pioneered by Swiss-born physicist Felix Bloch and others, the theory describes the electrons in crystals as residing in specific energy levels known as bands. If all the states in a group of bands are filled with electrons, then the electrons cannot move and the material is an insulator. If some of the states are unoccupied, then electrons can move from atom to atom and the material is capable of conducting an electrical current.

    Because of the symmetry properties of crystals, however, the quantum states of electrons in solids have special properties. These states can be described as a set of interconnected bands characterized by their momentum, energy and shape. The connections between these bands, which on a graph resemble tangled spaghetti strands, give rise to topological behaviors such as those of electrons that can travel on surfaces or edges without resistance.

    The team used a systematic search to identify many previously undiscovered families of candidate topological materials. The approach combined tools from such disparate fields as chemistry, mathematics, physics and materials science.

    First, the team characterized all the possible electronic band structures arising from electronic orbitals at all the possible atomic positions for all possible crystal patterns, or symmetry groups, that exist in nature, with the exception of magnetic crystals. To search for topological bands, the team first found a way to enumerate all allowed non-topological bands, with the understanding that anything left out of the list must be topological. Using tools from group theory, the team organized into classes all the possible non-topological band structures that can arise in nature.

    Next, by employing a branch of mathematics known as graph theory — the same approach used by search engines to determine links between websites — the team determined the allowed connectivity patterns for all of the band structures. The bands can either separate or connect together. The mathematical tools determine all the possible band structures in nature — both topological and non-topological. But having already enumerated the non-topological ones, the team was able to show which band structures are topological.

    By looking at the symmetry and connectivity properties of different crystals, the team identified several crystal structures that, by virtue of their band connectivity, must host topological bands. The team has made all of the data about non-topological bands and band connectivity available to the public through the Bilbao Crystallographic Server. “Using these tools, along with our results, researchers from around the world can quickly determine if a material of interest can potentially be topological,” Elcoro said.

    The research shows that symmetry, topology, chemistry and physics all have a fundamental role to play in our understanding of materials, Bernevig said. “The new theory embeds two previously missing ingredients, band topology and orbital hybridization, into Bloch’s theory and provides a prescriptive path for the discovery and characterization of metals and insulators with topological properties.”

    David Vanderbilt, a professor of physics and astronomy at Rutgers University who was not involved in the study, called the work remarkable. “Most of us thought it would be many years before the topological possibilities could be catalogued exhaustively in this enormous space of crystal classes,” Vanderbilt said. “This is why the work of Bradlyn and co-workers comes as such a surprise. They have developed a remarkable set of principles and algorithms that allow them to construct this catalogue at a single stroke. Moreover, they have combined their theoretical approach with materials database search methods to make concrete predictions of a wealth of new topological insulator materials.”

    The theoretical underpinnings for these materials, called “topological” because they are described by properties that remain intact when an object is stretched, twisted or deformed, led to the awarding of the Nobel Prize in physics in 2016 to F. Duncan M. Haldane, Princeton’s Sherman Fairchild University Professor of Physics; J. Michael Kosterlitz of Brown University; and David J. Thouless of the University of Washington.

    Chemistry and physics take different approaches to describing crystalline materials, in which atoms occur in regularly ordered patterns or symmetries. Chemists tend to focus on the atoms and their surrounding clouds of electrons, known as orbitals. Physicists tend to focus on the electrons themselves, which can carry electric current when they hop from atom to atom and are described by their momentum.

    “This simple fact — that the physics of electrons is usually described in terms of momentum, while the chemistry of electrons is usually described in terms of electronic orbitals — has left material discovery in this field at the mercy of chance,” Wang said.

    “We initially set out to better understand the chemistry of topological materials — to understand why some materials have to be topological,” Vergniory said.

    Aroyo added, “What came out was, however, much more interesting: a way to marry chemistry, physics and mathematics that adds the last missing ingredient in a century-old theory of electronics, and in the present-day search for topological materials.”

    Funding for the study was provided by the U.S. Department of Energy (DE-SC0016239), the U.S. National Science Foundation (EAGER DMR-1643312 and MRSEC DMR-1420541), and the U.S. Office of Naval Research (N00014-14-1-0330). Additional funding came from a Simons Investigator Award, the David & Lucile Packard Foundation, and Princeton University’s Eric and Wendy Schmidt Transformative Technology Fund. Funding was also provided by the Spanish Ministry of Economy and Competitiveness (FIS2016-75862-P and FIS2013-48286-C2-1-P), the Government of the Basque Country (project IT779-13), and the Spanish Ministry of Economy and Competitiveness and European Federation for Regional Development (MAT2015-66441-P).

    The study, Topological quantum chemistry, by Barry Bradlyn, Luis Elcoro, Jennifer Cano, Maia Garcia Vergniory, Zhijun Wang, Claudia Felser, Mois Aroyo and B. Andrei Bernevig, was published in the journal Nature on July 20, 2017.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    Princeton University Campus

    About Princeton: Overview

    Princeton University is a vibrant community of scholarship and learning that stands in the nation’s service and in the service of all nations. Chartered in 1746, Princeton is the fourth-oldest college in the United States. Princeton is an independent, coeducational, nondenominational institution that provides undergraduate and graduate instruction in the humanities, social sciences, natural sciences and engineering.

    As a world-renowned research university, Princeton seeks to achieve the highest levels of distinction in the discovery and transmission of knowledge and understanding. At the same time, Princeton is distinctive among research universities in its commitment to undergraduate teaching.

    Today, more than 1,100 faculty members instruct approximately 5,200 undergraduate students and 2,600 graduate students. The University’s generous financial aid program ensures that talented students from all economic backgrounds can afford a Princeton education.

    Princeton Shield

     
  • richardmitnick 7:35 am on July 7, 2017 Permalink | Reply
    Tags: , , , Material Sciences, ,   

    From BNL: “Electron Orbitals May Hold Key to Unifying Concept of High-Temperature Superconductivity” 

    Brookhaven Lab

    July 6, 2017
    Karen McNulty Walsh,
    kmcnulty@bnl.gov
    (631) 344-8350

    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    1
    Iron-based superconductivity occurs in materials such as iron selenide (FeSe) that contain crystal planes made up of a square array of iron (Fe) atoms, depicted here. In these iron layers, each Fe atom has two active electron “clouds,” or orbitals—dxz (red) and dyz (blue)—each containing one electron. By directly visualizing the electron states in the iron planes of FeSe, the researchers revealed that that electrons in the dxz orbitals (red) do not form Cooper pairs or contribute to the superconductivity, but instead form an incoherent metallic state along the horizontal (x) axis. In contrast, all electrons in the dyz orbitals (blue) form strong Cooper pairs with neighboring atoms to generate superconductivity. Searching for other materials with this exotic “orbital-selective” pairing may lead to the discovery of new superconductors. No image credit.

    2
    The custom-built Spectroscopic Imaging Scanning Tunneling Microscope used for these experiments stands one meter high, with cryogenic circuitry at the top for cooling samples to temperatures just above absolute zero (nearly -273 degrees Celsius). Inside, a needle with single atom on the end scans across the crystal surface in steps as small as 2 trillionths of a meter, measuring the electron tunneling current at each location. These measurements reveal the quantum wavefunctions of electrons in the material with exquisite precision. No image credit.

    A team of scientists has found evidence for a new type of electron pairing that may broaden the search for new high-temperature superconductors. The findings, described in the journal Science, provide the basis for a unifying description of how radically different “parent” materials—insulating copper-based compounds and metallic iron-based compounds—can develop the ability to carry electrical current with no resistance at strikingly high temperatures.

    According to the scientists, the materials’ dissimilar electronic characteristics actually hold the key to commonality.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world. Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

     
  • richardmitnick 1:35 pm on June 23, 2017 Permalink | Reply
    Tags: , , , , Magnetic materials, Magnetocaloric effect, Material Sciences,   

    From Ames Lab- “Scientists’ surprising discovery: making ferromagnets stronger by adding non-magnetic element” 


    Ames Laboratory

    June 23, 2017
    Yaroslav Mudryk
    Division of Materials Science and Engineering
    (515) 294-2728
    slovkomk@ameslab.gov

    Durga Paudyal
    Division of Materials Science and Engineering
    (515)-294-2041
    durga@ameslab.gov

    Laura Millsaps
    Ames Laboratory Public Affairs
    (515) 294-3474
    millsaps@ameslab.gov

    1
    No image caption or credit.

    Researchers at the U.S. Department of Energy’s Ames Laboratory discovered that they could functionalize magnetic materials through a thoroughly unlikely method, by adding amounts of the virtually non-magnetic element scandium to a gadolinium-germanium alloy.

    It was so unlikely they called it a “counterintuitive experimental finding” in their published work on the research.

    “People don’t talk much about scandium when they are talking magnetism, because there has not been much reason to,” said Yaroslav Mudryk, an Associate Scientist at Ames Laboratory. “It’s rare, expensive, and displays virtually no magnetism.”

    “Conventional wisdom says if you take compound A and compound B and combine them together, most commonly you get some combination of the properties of each. In the case of the addition of scandium to gadolinium, however, we observed an abrupt anomaly.”

    Years of research exploring the properties of magnetocaloric materials, relating back to the discovery of the giant magnetocaloric effect in rare earth alloys in 1997 by Vitalij Pecharsky and the late Karl Gschneidner, Jr., laid the groundwork for computational theory to begin “hunting” for hidden properties in magnetic rare-earth compounds that could be discovered by introducing small amounts of other elements, altering the electronic structure of known materials.

    “From computations, we projected that scandium may bring something really unusual to the table: we saw an unexpectedly large magnetic moment developing on its lone 3d electron,” said Ames Laboratory Associate Scientist Durga Paudyal. “It is the hybridization between gadolinium 5d and the scandium 3d states that is the key that strengthens magnetism with the scandium and transforms it to a ferromagnetic state.”

    “Basic research takes time to bear fruit. This is an exemplary case when 20 years ago our team started looking into what are called the 5:4 compounds,” said Ames Laboratory group leader and Iowa State University Distinguished Professor Vitalij Pecharsky. “Only now we have learned enough about these unique rare earth element-containing materials to become not only comfortable but precise in predicting how to manipulate their properties at will.”

    The discovery could greatly change the way scandium and other ‘conventionally’ non-magnetic elements are considered and used in magnetic materials research and development, and possibly creates new tools for controlling, manipulating, and functionalizing useful magnetic rare-earth compounds.

    The research is further discussed in the paper, Enhancing Magnetic Functionality with Scandium: Breaking Stereotypes in the Design of Rare Earth Materials, authored by Yaroslav Mudryk, Durga Paudyal, Jing Liu, and Vitalij K. Pecharsky; and published in the Chemistry of Materials.

    The work was supported by the U.S. Department of Department of Energy’s Office of Science.

    Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

    DOE’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit http://science.energy.gov.

    See the full article here .

    Please help promote STEM in your local schools.
    STEM Icon
    Stem Education Coalition

    Ames Laboratory is a government-owned, contractor-operated research facility of the U.S. Department of Energy that is run by Iowa State University.

    For more than 60 years, the Ames Laboratory has sought solutions to energy-related problems through the exploration of chemical, engineering, materials, mathematical and physical sciences. Established in the 1940s with the successful development of the most efficient process to produce high-quality uranium metal for atomic energy, the Lab now pursues a broad range of scientific priorities.

    Ames Laboratory is a U.S. Department of Energy Office of Science national laboratory operated by Iowa State University. Ames Laboratory creates innovative materials, technologies and energy solutions. We use our expertise, unique capabilities and interdisciplinary collaborations to solve global problems.

    Ames Laboratory is supported by the Office of Science of the U.S. Department of Energy. The Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
    DOE Banner

    DOE Banner

     
  • richardmitnick 8:06 am on June 23, 2017 Permalink | Reply
    Tags: A Single Electron’s Tiny Leap Sets Off ‘Molecular Sunscreen’ Response, , , , , Material Sciences, ,   

    From SLAC: “A Single Electron’s Tiny Leap Sets Off ‘Molecular Sunscreen’ Response” 


    SLAC Lab

    June 22, 2017
    Glennda Chui

    1
    Thymine – the molecule illustrated in the foreground – is one of the four basic building blocks that make up the double helix of DNA. It’s such a strong absorber of ultraviolet light that the UV in sunlight should deactivate it, yet this does not happen. Researchers used an X-ray laser at SLAC National Accelerator Laboratory to observe the infinitesimal leap of a single electron that sets off a protective response in thymine molecules, allowing them to shake off UV damage. (Greg Stewart/SLAC National Accelerator Laboratory)

    In experiments at the Department of Energy’s SLAC National Accelerator Laboratory, scientists were able to see the first step of a process that protects a DNA building block called thymine from sun damage: When it’s hit with ultraviolet light, a single electron jumps into a slightly higher orbit around the nucleus of a single oxygen atom.

    This infinitesimal leap sets off a response that stretches one of thymine’s chemical bonds and snaps it back into place, creating vibrations that harmlessly dissipate the energy of incoming ultraviolet light so it doesn’t cause mutations.

    The technique used to observe this tiny switch-flip at SLAC’s Linac Coherent Light Source (LCLS) X-ray free-electron laser can be applied to almost any organic molecule that responds to light – whether that light is a good thing, as in photosynthesis or human vision, or a bad thing, as in skin cancer, the scientists said. They described the study in Nature Communications today.

    SLAC/LCLS

    “All of these light-sensitive organic molecules tend to absorb light in the ultraviolet. That’s not only why you get sunburn, but it’s also why your plastic eyeglass lenses offer some UV protection,” said Phil Bucksbaum, a professor at SLAC and Stanford University and director of the Stanford PULSE Institute at SLAC. “You can even see these effects in plastic lawn furniture – after a couple of seasons it can become brittle and discolored simply due to the fact that the plastic was absorbing ultraviolet light all the time, and the way it absorbs sun results in damage to its chemical bonds.”

    Catching Electrons in Action

    Thymine and the other three DNA building blocks also strongly absorb ultraviolet light, which can trigger mutations and skin cancer, yet these molecules seem to get by with minimal damage. In 2014, a team led by Markus Guehr ­– then a SLAC senior staff scientist and now on the faculty of the University of Potsdam in Germany – reported that they had found the answer: The stretch-snap of a single bond and resulting energy-dissipating vibrations, which took place within 200 femtoseconds, or millionths of a billionth of a second after UV light exposure.

    But what made the bond stretch? The team knew the answer had to involve electrons, which are responsible for forming, changing and breaking bonds between atoms. So they devised an ingenious way to catch the specific electron movements that trigger the protective response.

    It relied on the fact that electrons don’t orbit an atom’s nucleus in neat concentric circles, like planets orbiting a sun, but rather in fuzzy clouds that take a different shape depending on how far they are from the nucleus. Some of these orbitals are in fact like a fuzzy sphere; others look a little like barbells or the start of a balloon animal. You can see examples here.

    2
    No image caption or credit, but there is a comment,
    “I see the distribution in different orbitals. So if for example I take the S orbitals, they are all just a sphere. So wont the 2S orbital overlap with the 1S overlap, making the electrons in each orbital “meet” at some point? Or have I misunderstood something?”

    Strong Signal Could Solve Long-Standing Debate

    For this new experiment, the scientists hit thymine molecules with a pulse of UV laser light and tuned the energy of the LCLS X-ray laser pulses so they would home in on the response of the oxygen atom that’s at one end of the stretching, snapping bond.

    The energy from the UV light excited one of the atom’s electrons to jump into a higher orbital. This left the atom in a sort of tippy state where just a little more energy would boost a second electron into a higher orbital; and that second jump is what sets off the protective response, changing the shape of the molecule just enough to stretch the bond.

    The first jump, which was previously known to happen, is difficult to detect because the electron winds up in a rather diffuse orbital cloud, Guehr said. But the second, which had never been observed before, was much easier to spot because that electron ended up in an orbital with a distinctive shape that gave off a big signal.

    “Although this was a very tiny electron movement, the signal kind of jumped out at us in the experiment,” Guehr said. “I always had a feeling this would be a strong transition, just intuitively, but when we saw this come in it was a special moment, one of the best moments an experimentalist can have.”

    Settling a Longstanding Debate

    Study lead author Thomas Wolf, an associate staff scientist at SLAC, said the results should settle a longstanding debate about how long after UV exposure the protective response kicks in: It happens 60 femtoseconds after UV light hits. This time span is important, he said, because the longer the atom spends in the tippy state between the first jump and the second, the more likely it is to undergo some sort of reaction that could damage the molecule.

    Henrik Koch, a theorist at NTNU in Norway who was a guest professor at Stanford at the time, led the study with Guehr. He led the effort to model, understand and interpret what happened in the experiment, and he participated in it to an unusual extent, Guehr said.

    “He is extremely experienced in applying theory to methodology development, and he had this curiosity to bring this to our experiment,” Guehr said. “He was so fascinated by this research that he did something completely untypical of a theorist – he came to LCLS, into the control room, and he wanted to see the data coming in. I found that completely amazing and very motivating. It turned out that some of my previous thinking was completely right but other aspects were completely wrong, and Henrik did the right theory at the right level so we could learn from it.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
    i1

     
  • richardmitnick 6:36 am on June 15, 2017 Permalink | Reply
    Tags: , , , , Material Sciences, , RIXS, SIMES - Stanford Institute for Materials & Energy Sciences,   

    From SLAC: “New Research Finds a Missing Piece to High-Temperature Superconductor Mystery” 


    SLAC Lab

    June 14, 2017
    Mike Ross

    1
    This sketch shows how resonant inelastic X-ray scattering (RIXS) helps scientists understand the electronic behavior of copper oxide materials. An X-ray photon aimed at the sample (blue arrow) is absorbed by a copper atom, which then emits a new, lower-energy photon (red arrow) as it relaxes. The amount of momentum transferred and energy lost in this process can induce changes in the charge density waves thought to be important in high-temperature superconductivity. (Wei-Sheng/SLAC National Accelerator Laboratory)

    An international team led by scientists from the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University has detected new features in the electronic behavior of a copper oxide material that may help explain why it becomes a perfect electrical conductor – a superconductor – at relatively high temperatures.

    Using an ultrahigh-resolution X-ray instrument in France, the researchers for the first time saw dynamic behaviors in the material’s charge density wave (CDW) – a pattern of electrons that resembles a standing wave – that lend support to the idea that these waves may play a role in high-temperature superconductivity.

    Data taken at low (20 kelvins) and high (240 kelvins) temperatures showed that as the temperature increased, the CDW became more aligned with the material’s atomic structure. Remarkably, at the lower temperature, the CDW also induced an unusual increase in the intensity of the oxide’s atomic lattice vibrations, indicating that the dynamic CDW behaviors can propagate through the lattice.

    “Previous research has shown that when the CDW is static, it competes with and diminishes superconductivity,” said co-author Wei-Sheng Lee, a SLAC staff scientist and investigator with the Stanford Institute for Materials and Energy Sciences (SIMES), which led the study published June 12 in Nature Physics. “If, on the other hand, the CDW is not static but fluctuating, theory tells us they may actually help form superconductivity.”

    A Decades-long Search for an Explanation

    The new result is the latest in a decades-long search by researchers worldwide for the factors that enable certain materials to become superconducting at relatively high temperatures.

    Since the 1950s, scientists have known how certain metals and simple alloys become superconducting when chilled to within a few degrees of absolute zero: Their electrons pair up and ride waves of atomic vibrations that act like a virtual glue to hold the pairs together. Above a certain temperature, however, the glue fails as thermal vibrations increase, the electron pairs split up and superconductivity disappears.

    In 1986, complex copper oxide materials were found to become superconducting at much higher – although still quite cold – temperatures. This discovery was so unexpected it caused a worldwide scientific sensation. By understanding and optimizing how these materials work, researchers hope to develop superconductors that work at room temperature and above.

    At first, the most likely glue holding superconducting electron pairs together at higher temperatures seemed to be strong magnetic excitations created by interactions between electron spins. But in 2014, a theoretical simulation and experiments led by SIMES researchers concluded that these high-energy magnetic interactions are not the sole factor in copper oxide’s high-temperature superconductivity. An unanticipated CDW also appeared to be important.

    The latest results continue the SIMES collaboration between experiment and theory. Building upon previous theories of how electron interactions with lattice vibrations can be probed with resonant inelastic X-ray scattering, or RIXS, the signature of CDW dynamics was finally identified, providing additional support for the CDW’s role in determining the electronic structure in superconducting copper oxides.

    The Essential New Tool: RIXS

    The new results are enabled by the development of more capable instruments employing RIXS. Now available at ultrahigh resolution at the European Synchrotron Radiation Facility (ESRF) in France, where the team performed this experiment, RIXS will also be an important feature of SLAC’s upgraded Linac Coherent Light Source X-ray free-electron laser, LCLS-II.


    ESRF. Grenoble, France

    SLAC LCLS-II

    The combination of ultrahigh energy resolution and a high pulse repetition rate at LCLS-II will enable researchers to see more detailed CDW fluctuations and perform experiments aimed at revealing additional details of its behavior and links to high-temperature superconductivity. Most importantly, researchers at LCLS-II will be able to use ultrafast light-matter interactions to control CDW fluctuations and then take femtosecond-timescale snapshots of them.

    RIXS involves illuminating a sample with X-rays that have just enough energy to excite some electrons deep inside the target atoms to jump up into a specific higher orbit. When the electrons relax back down into their previous positions, a tiny fraction of them emit X-rays that carry valuable atomic-scale information about the material’s electronic and magnetic configuration that is thought to be important in high-temperature superconductivity.

    “To date, no other technique has seen evidence of propagating CDW dynamics,” Lee said.

    RIXS was first demonstrated in the mid-1970s [Physical Review Letters], but it could not obtain useful information to address key problems until 2007, when Giacomo Ghiringhelli, Lucio Braicovich at Milan Polytechnic in Italy and colleagues at Swiss Light Source made a fundamental change that improved its energy resolution to a level where significant details became visible – technically speaking to about 120 milli-electronvolts (meV) at the relevant X-ray wavelength, which is called a copper L edge. The new RIXS instrument at ESRF is three times better, routinely attaining an energy resolution down to 40 meV. Since 2014, the Milan group has collaborated with SLAC and Stanford scientists in their RIXS research.

    “The new ultrahigh resolution RIXS makes a huge difference,” Lee said. “It can show us previously invisible details.”

    Other researchers involved in this result were from Milan Polytechnic, European Synchrotron Radiation Facility, Japan’s National Institute of Advanced Industrial Science and Technology and Italy’s National Research Council Institute for Superconductors, Oxides and Other Innovative Materials and Devices (CNR-SPIN). Funding for this research came from the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    SLAC Campus
    SLAC is a multi-program laboratory exploring frontier questions in photon science, astrophysics, particle physics and accelerator research. Located in Menlo Park, California, SLAC is operated by Stanford University for the DOE’s Office of Science.
    i1

     
  • richardmitnick 3:22 pm on June 9, 2017 Permalink | Reply
    Tags: , , , Dynamic boundary, Liquid crystal study, Material Sciences, , Phononic or optomechanical applications, , Scattering angle, Tracking dynamic molecular features in soft materials including the high-frequency molecular vibrations that transmit waves of heat sound and other forms of energy, Tuning the structure   

    From BNL: “X-ray Study Reveals Way to Control Molecular Vibrations that Transmit Heat” 

    Brookhaven Lab

    June 6, 2017
    Karen McNulty Walsh
    kmcnulty@bnl.gov
    (631) 344-8350

    Peter Genzer
    genzer@bnl.gov
    (631) 344-3174

    Findings open new pathway for “tuning” materials to ease or insulate against the flow of heat, sound, and other forms of energy.

    1
    Brookhaven Lab members of the research team at the IXS beamline of the National Synchrotron Light Source II, left to right: Dima Bolmatov, Alessandro Cunsolo, Mikhail Zhernenkov, Ronald Pindak (sitting), Alexei Suvorov (sitting), and Yong Cai. The circular track accommodates utility cables and allows the arm housing the detectors to move to different locations to select the scattering angle for the measurement.

    Scientists at the U.S. Department of Energy’s (DOE) Brookhaven National Laboratory have developed a new way to track dynamic molecular features in soft materials, including the high-frequency molecular vibrations that transmit waves of heat, sound, and other forms of energy. Controlling these vibrational waves in soft materials such as polymers or liquid crystal compounds could lead to a range of energy-inspired innovations—from thermal and acoustic insulators, to ways to convert waste heat into electricity, or light into mechanical motion.

    In a paper just published in Nano Letters, the scientists describe using the newly constructed inelastic x-ray scattering (IXS) beamline at the National Synchrotron Light Source II (NSLS-II), which has unprecedented energy resolution, to monitor the propagation of vibrations through a liquid crystal compound in three different phases.


    BNL NSLS-II

    Their findings show that the nanoscale structural changes that occur with increasing temperature—as the liquid crystals become less ordered—dramatically disrupt the flow of vibrational waves. Thus choosing or changing the “phase,” or arrangement of molecules, could control the vibrations and the flow of energy.

    “By tuning the structure, we can change the dynamic properties of this material,” said Brookhaven physicist Dima Bolmatov, the paper’s lead author.

    The technique could also be used to study dynamic processes in other soft systems such as biological membranes or any kind of complex fluid.

    “For example, we could look at how the lipid molecules in a cell membrane cooperate with each other to create tiny porous regions where even smaller molecules, like oxygen or carbon dioxide, can pass through—to see how gas exchange operates in gills and lungs,” Bolmatov said.

    The ability to track such fast dynamic properties would not be possible without the unique capabilities of NSLS-II—a DOE Office of Science User Facility at Brookhaven Lab. NSLS-II produces extremely bright x-rays for studies in a wide range of scientific fields.

    At the IXS beamline, scientists bombard samples with these x-rays and measure the energy they give up or gain with a precision to within two thousandths of an electron volt, as well as the angle at which they scatter off the sample—even at very small angles.

    The energy exchange tells us how much energy it took to make some molecules vibrate in a wave-like motion. The scattering angle probes the vibrations propagating over different length scales inside the sample—from nearly a single molecule to tens of nanometers. The new IXS beamline at NSLS-II can resolve those length scales with unprecedented precision,” said Yong Cai, the lead scientist of the IXS beamline.

    “These two parameters—the scattering angle and the energy—have never before been so well measured in soft materials. So the technical properties of this beamline enable us to precisely locate the vibrations and track their propagation in different directions over different length scales—even in materials that lack a well-ordered solid structure,” he added.

    2
    The colorful scattering pattern at left reveals molecular level structural information about the layered smectic phase of a liquid crystal material. The inner arcs indicate that the molecules are arrayed in ordered layers with regular spacing, while the outer arcs indicate there is still liquid-like mobility within the layers. The graph (top, right) represents inelastic x-ray scattering measurements from this smectic phase. Each peak (pink, orange, purple) represents a unique vibrational motion moving through the material, where the two “bumps” that make up each peak represent the energy gained or lost by the vibration. The purple and orange vibrations match the frequency of sound waves while the third, pink, vibration is linked to the tilt of the molecules (bottom, right). The out-of-phase rocking back-and-forth of these molecules matches the frequency of infrared light (heat).

    In the liquid crystal study, the Brookhaven Lab scientists and their collaborators at Kent State University and the University at Albany made measurements at three different temperatures as the material went from an ordered, crystalline phase through transitions to a less-ordered “smectic” state, and finally an “isotropic” liquid. They easily detected the propagation of vibrational waves through the most ordered phase, and showed that the emergence of disorder “killed” the propagation of low energy “acoustic shear” vibrations. Acoustic shear vibrations are associated with a compression of the molecules in a direction perpendicular to the direction of propagation.

    “Knowing where the dynamic boundary is—between the material behaving like an ordered solid and a disordered soft material—gives us a way to control the transmission of energy at the nanoscale,” Bolmatov said.

    In the “smectic” phase, the scientists also observed a vibration that was associated instead with molecular tilt. This type of vibration can interact with light and absorb it because the terahertz frequency of the vibrations matches the frequency of infrared light or heat waves. So changing the material properties can control the way these forms of energy move through the material. Those changes can be achieved by changing the temperature of the material, as was done in this experiment, but also by applying external electric or magnetic fields, Bolmatov said.

    This paves the way for new so-called phononic or optomechanical applications, where sound or light is coupled with the mechanical vibrations. Such coupling makes it possible to control a material by applying external light and sound or vice versa.

    “We’re all familiar with applications using the optical properties of liquid crystals in display screens,” Bolmatov said. “We’ve found new properties that can be controlled or manipulated for new kinds of applications.”

    The team will continue studies of soft materials at IXS, including planned experiments with block copolymers, nanoparticle assemblies, lipid membranes, and other liquid crystals over the summer.

    “The IXS beamline is also now opened to external users—including scientists interested in these and other soft materials and biological processes,” said Cai.

    The research team included Dima Bolmatov, Mikhail Zhernenkov, Alexey Suvorov, Ronald Pindak, Yong Cai, and Alessandro Cunsolo of NSLS-II, and Lewis Sharpnack, Deña M. Agra-Kooijman of Kent State University, and Satyendra Kumar of the University at Albany .

    This research was supported by the DOE Office of Science.

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition
    BNL Campus

    One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. The Laboratory’s almost 3,000 scientists, engineers, and support staff are joined each year by more than 5,000 visiting researchers from around the world.Brookhaven is operated and managed for DOE’s Office of Science by Brookhaven Science Associates, a limited-liability company founded by Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit, applied science and technology organization.
    i1

     
  • richardmitnick 8:19 pm on June 7, 2017 Permalink | Reply
    Tags: A more sustainable way to refine metals, , Material Sciences,   

    From McGill: “A more sustainable way to refine metals” 

    McGill University

    McGill University

    7Jun2017
    Contact Information
    Contact:
    Prof. Jean-Philippe Lumb
    jean-philip.lumb@mcgill.ca
    514 398-4201

    Secondary Contact Information
    Contact:
    Chris Chipello
    christopher.chipello@mcgill.ca

    New method could reduce environmental impact of extracting metals from raw materials and post-consumer electronics.

    1
    Strategy for reducing the environmental impact of a refining process: replace hazardous chemicals with more benign and recyclable compounds. CREDIT: Michael J. Krause (Western University)

    A team of chemists in Canada has developed a way to process metals without using toxic solvents and reagents. The system, which also consumes far less energy than conventional techniques, could greatly shrink the environmental impact of producing metals from raw materials or from post-consumer electronics.

    “At a time when natural deposits of metals are on the decline, there is a great deal of interest in improving the efficiency of metal refinement and recycling, but few disruptive technologies are being put forth,” says Jean-Philip Lumb, an associate professor in McGill University’s Department of Chemistry. “That’s what makes our advance so important.

    The discovery stems from a collaboration between Lumb and Tomislav Friščić at McGill in Montreal, and Kim Baines of Western University in London, Ont. In an article published recently in Science Advances, the researchers outline an approach that uses organic molecules, instead of chlorine and hydrochloric acid, to help purify germanium, a metal used widely in electronic devices. Laboratory experiments by the researchers have shown that the same technique can be used with other metals, including zinc, copper, manganese and cobalt.

    The research could mark an important milestone for the “green chemistry” movement, which seeks to replace toxic reagents used in conventional industrial manufacturing with more environmentally friendly alternatives. Most advances in this area have involved organic chemistry – the synthesis of carbon-based compounds used in pharmaceuticals and plastics, for example.

    “Applications of green chemistry lag far behind in the area of metals,” Lumb says. “Yet metals are just as important for sustainability as any organic compound. For example, electronic devices require numerous metals to function.”

    Taking a page from biology

    There is no single ore rich in germanium, so it is generally obtained from mining operations as a minor component in a mixture with many other materials. Through a series of processes, that blend of matter can be reduced to germanium and zinc.

    “Currently, in order to isolate germanium from zinc, it’s a pretty nasty process,” Baines explains. The new approach developed by the McGill and Western chemists “enables you to get germanium from zinc, without those nasty processes.”

    To accomplish this, the researchers took a page from biology. Lumb’s lab for years has conducted research into the chemistry of melanin, the molecule in human tissue that gives skin and hair their color. Melanin also has the ability to bind to metals. “We asked the question: ‘Here’s this biomaterial with exquisite function, would it be possible to use it as a blueprint for new, more efficient technologies?’”

    The scientists teamed up to synthesize a molecule that mimics some of the qualities of melanin. In particular, this “organic co-factor” acts as a mediator that helps to extract germanium at room temperature, without using solvents.


    Using solvent-free mechanochemical techniques, milling jars containing stainless-steel balls are shaken at high speeds to promote chemical reactions. CREDIT: Michael Brand (University of Cardiff) and Jean-Louis Do (McGill University)

    Next step: industrial scale

    The system also taps into Friščić’s expertise in mechanochemistry, an emerging branch of chemistry that relies on mechanical force – rather than solvents and heat – to promote chemical reactions. Milling jars containing stainless-steel balls are shaken at high speeds to help purify the metal.

    “This shows how collaborations naturally can lead to sustainability-oriented innovation,” Friščić says. “Combining elegant new chemistry with solvent-free mechanochemical techniques led us to a process that is cleaner by virtue of circumventing chlorine-based processing, but also eliminates the generation of toxic solvent waste”

    The next step in developing the technology will be to show that it can be deployed economically on industrial scales, for a range of metals.

    “There’s a tremendous amount of work that needs to be done to get from where we are now to where we need to go,” Lumb says. “But the platform works on many different kinds of metals and metal oxides, and we think that it could become a technology adopted by industry. We are looking for stakeholders with whom we can partner to move this technology forward.”

    Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the National Natural Science Foundation of China, the Soochow University-Western University Center for Synchrotron Radiation Research, and the Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University.

    “A chlorine-free protocol for processing germanium,” Martin Glavinović et al., Science Advances, 5 May 2017. DOI: 10.1126/sciadv.1700149 http://advances.sciencemag.org/content/3/5/e1700149

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    All about McGill

    With some 300 buildings, more than 38,500 students and 250,000 living alumni, and a reputation for excellence that reaches around the globe, McGill has carved out a spot among the world’s greatest universities.
    Founded in Montreal, Quebec, in 1821, McGill is a leading Canadian post-secondary institution. It has two campuses, 11 faculties, 11 professional schools, 300 programs of study and some 39,000 students, including more than 9,300 graduate students. McGill attracts students from over 150 countries around the world, its 8,200 international students making up 21 per cent of the student body.

     
c
Compose new post
j
Next post/Next comment
k
Previous post/Previous comment
r
Reply
e
Edit
o
Show/Hide comments
t
Go to top
l
Go to login
h
Show/Hide help
shift + esc
Cancel
%d bloggers like this: