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  • richardmitnick 10:06 am on January 10, 2020 Permalink | Reply
    Tags: , , Julia Ortony, , Nanotechnology, Self-assembling nanostructures,   

    From MIT News: Women in STEM- “Julia Ortony: Concocting nanomaterials for energy and environmental applications” 

    MIT News

    From MIT News

    January 9, 2020
    Leda Zimmerman | MIT Energy Initiative

    1
    Julia Ortony is the Finmeccanica Career Development Assistant Professor of Engineering in the Department of Materials Science and Engineering. Photo: Lillie Paquette/School of Engineering

    2
    Assistant Professor Julia Ortony (right) and graduate student William Lindemann discuss his experiments on self-assembling nanofibers. Work at the Ortony lab focuses on molecular design and synthesis to create new soft nanomaterials for tackling problems related to energy and the environment. Photo: Lillie Paquette/School of Engineering

    The MIT assistant professor is entranced by the beauty she finds pursuing chemistry.

    A molecular engineer, Julia Ortony performs a contemporary version of alchemy.

    “I take powder made up of disorganized, tiny molecules, and after mixing it up with water, the material in the solution zips itself up into threads 5 nanometers thick — about 100 times smaller than the wavelength of visible light,” says Ortony, the Finmeccanica Career Development Assistant Professor of Engineering in the Department of Materials Science and Engineering (DMSE). “Every time we make one of these nanofibers, I am amazed to see it.”

    But for Ortony, the fascination doesn’t simply concern the way these novel structures self-assemble, a product of the interaction between a powder’s molecular geometry and water. She is plumbing the potential of these nanomaterials for use in renewable energy and environmental remediation technologies, including promising new approaches to water purification and the photocatalytic production of fuel.

    Tuning molecular properties

    Ortony’s current research agenda emerged from a decade of work into the behavior of a class of carbon-based molecular materials that can range from liquid to solid.

    During doctoral work at the University of California at Santa Barbara, she used magnetic resonance (MR) spectroscopy to make spatially precise measurements of atomic movement within molecules, and of the interactions between molecules. At Northwestern University, where she was a postdoc, Ortony focused this tool on self-assembling nanomaterials that were biologically based, in research aimed at potential biomedical applications such as cell scaffolding and regenerative medicine.

    “With MR spectroscopy, I investigated how atoms move and jiggle within an assembled nanostructure,” she says. Her research revealed that the surface of the nanofiber acted like a viscous liquid, but as one probed further inward, it behaved like a solid. Through molecular design, it became possible to tune the speed at which molecules that make up a nanofiber move.

    A door had opened for Ortony. “We can now use state-of-matter as a knob to tune nanofiber properties,” she says. “For the first time, we can design self-assembling nanostructures, using slow or fast internal molecular dynamics to determine their key behaviors.”

    Slowing down the dance

    When she arrived at MIT in 2015, Ortony was determined to tame and train molecules for nonbiological applications of self-assembling “soft” materials.

    “Self-assembling molecules tend to be very dynamic, where they dance around each other, jiggling all the time and coming and going from their assembly,” she explains. “But we noticed that when molecules stick strongly to each other, their dynamics get slow, and their behavior is quite tunable.” The challenge, though, was to synthesize nanostructures in nonbiological molecules that could achieve these strong interactions.

    “My hypothesis coming to MIT was that if we could tune the dynamics of small molecules in water and really slow them down, we should be able to make self-assembled nanofibers that behave like a solid and are viable outside of water,” says Ortony.

    Her efforts to understand and control such materials are now starting to pay off.

    “We’ve developed unique, molecular nanostructures that self-assemble, are stable in both water and air, and — since they’re so tiny — have extremely high surface areas,” she says. Since the nanostructure surface is where chemical interactions with other substances take place, Ortony has leapt to exploit this feature of her creations — focusing in particular on their potential in environmental and energy applications.

    Clean water and fuel from sunlight

    One key venture, supported by Ortony’s Professor Amar G. Bose Fellowship, involves water purification. The problem of toxin-laden drinking water affects tens of millions of people in underdeveloped nations. Ortony’s research group is developing nanofibers that can grab deadly metals such as arsenic out of such water. The chemical groups she attaches to nanofibers are strong, stable in air, and in recent tests “remove all arsenic down to low, nearly undetectable levels,” says Ortony.

    She believes an inexpensive textile made from nanofibers would be a welcome alternative to the large, expensive filtration systems currently deployed in places like Bangladesh, where arsenic-tainted water poses dire threats to large populations.

    “Moving forward, we would like to chelate arsenic, lead, or any environmental contaminant from water using a solid textile fabric made from these fibers,” she says.

    In another research thrust, Ortony says, “My dream is to make chemical fuels from solar energy.” Her lab is designing nanostructures with molecules that act as antennas for sunlight. These structures, exposed to and energized by light, interact with a catalyst in water to reduce carbon dioxide to different gases that could be captured for use as fuel.

    In recent studies, the Ortony lab found that it is possible to design these catalytic nanostructure systems to be stable in water under ultraviolet irradiation for long periods of time. “We tuned our nanomaterial so that it did not break down, which is essential for a photocatalytic system,” says Ortony.

    Students dive in

    While Ortony’s technologies are still in the earliest stages, her approach to problems of energy and the environment are already drawing student enthusiasts.

    Dae-Yoon Kim, a postdoc in the Ortony lab, won the 2018 Glenn H. Brown Prize from the International Liquid Crystal Society for his work on synthesized photo-responsive materials and started a tenure track position at the Korea Institute of Science and Technology this fall. Ortony also mentors Ty Christoff-Tempesta, a DMSE doctoral candidate, who was recently awarded a Martin Fellowship for Sustainability. Christoff-Tempesta hopes to design nanoscale fibers that assemble and disassemble in water to create environmentally sustainable materials. And Cynthia Lo ’18 won a best-senior-thesis award for work with Ortony on nanostructures that interact with light and self-assemble in water, work that will soon be published. She is “my superstar MIT Energy Initiative UROP [undergraduate researcher],” says Ortony.

    Ortony hopes to share her sense of wonder about materials science not just with students in her group, but also with those in her classes. “When I was an undergraduate, I was blown away at the sheer ability to make a molecule and confirm its structure,” she says. With her new lab-based course for grad students — 3.65 (Soft Matter Characterization) — Ortony says she can teach about “all the interests that drive my research.”

    While she is passionate about using her discoveries to solve critical problems, she remains entranced by the beauty she finds pursuing chemistry. Fascinated by science starting in childhood, Ortony says she sought out every available class in chemistry, “learning everything from beginning to end, and discovering that I loved organic and physical chemistry, and molecules in general.”

    Today, she says, she finds joy working with her “creative, resourceful, and motivated” students. She celebrates with them “when experiments confirm hypotheses, and it’s a breakthrough and it’s thrilling,” and reassures them “when they come with a problem, and I can let them know it will be thrilling soon.”

    See the full article here .


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    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

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  • richardmitnick 10:30 pm on December 17, 2019 Permalink | Reply
    Tags: "Scientists discover how proteins form crystals that tile a microbe’s shell", , , , Nanotechnology, , ,   

    From SLAC National Accelerator Lab: “Scientists discover how proteins form crystals that tile a microbe’s shell” 

    From SLAC National Accelerator Lab

    December 17, 2019
    Glennda Chui

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    In this illustration, protein crystals join six-sided ’tiles’ forming at top left and far right, part of a protective shell worn by many microbes. A new study zooms in on the first steps of crystal formation and helps explain how microbial shells assemble themselves so quickly. Credit: Greg Stewart/SLAC National Accelerator Laboratory

    A new understanding of the nucleation process could shed light on how the shells help microbes interact with their environments, and help people design self-assembling nanostructures for various tasks.

    Many microbes wear beautifully patterned crystalline shells, which protect them from a harsh world and can even help them reel in food. Studies at the Department of Energy’s SLAC National Accelerator Laboratory and Stanford University have revealed this food-reeling process and shown how shells assemble themselves from protein building blocks.

    Now the same team has zoomed in on the very first step in microbial shell-building: nucleation, where squiggly proteins crystallize into sturdy building blocks, much like rock candy crystallizes around a string dipped into sugar syrup.

    The results, published today in the Proceedings of the National Academy of Sciences, could shed light on how the shells help microbes interact with other organisms and with their environments, and also help scientists design self-assembling nanostructures for various tasks.

    2

    Jonathan Herrmann, a graduate student in Professor Soichi Wakatsuki’s group at SLAC and Stanford, collaborated with the structural molecular biology team at SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) on the study.

    SLAC/SSRL

    They scattered a powerful beam of X-rays off protein molecules that were floating in a solution to see how the atomic structures of the molecules changed as they nucleated into crystals. Meanwhile, other researchers made a series of cryogenic electron microscope (cryo-EM) images at various points in the nucleation process to show what happened over time.

    They found out that crystal formation takes place in two steps: One end of the protein molecule nucleates into crystal while the other end, called the N-terminus, continues to wiggle around. Then the N-terminus joins in, and the crystallization is complete. Far from being a laggard, the N-terminus actually speeds up the initial nucleation step ­– although exactly how it does this is still unknown, the researchers said – and this helps explain why microbial shells can form so quickly and efficiently.

    Some of the X-ray data was collected at Lawrence Berkeley National Laboratory’s Advanced Light Source, which like SSRL is a DOE Office of Science user facility.

    LBNL ALS

    Researchers from the University of British Columbia and from Professor Lucy Shapiro’s laboratory at Stanford also contributed to this work, funded in part by the National Institute of General Medical Sciences and the Chan Zuckerberg Biohub. Work in Wakatsuki’s labs at SLAC and Stanford was funded by a Laboratory Directed Research and Development grant from SLAC, the DOE Office of Science’s Office of Biological and Environmental Research, and Stanford’s Precourt Institute for Energy.

    See the full article here .


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    SLAC/LCLS


    SLAC/LCLS II projected view


    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.
    The scientists used special software, designed by van den Bedem, that is highly sensitive to identifying protein movement from X-ray crystallography data to interpret the results, revealing never-before-seen motions that play a key role in catalyzing complex reactions, such as breaking down antibiotics. Next, the researchers hope to use LCLS to obtain room temperature structures of other enzymes to get a better look at how the motions occurring within them help move along reactions.
    SSRL and LCLS are DOE Office of Science user facilities. This work was funded by the DOE Office of Science and the National Institutes of Health, among other sources.

     
  • richardmitnick 3:30 pm on December 16, 2019 Permalink | Reply
    Tags: "Nanoscience breakthrough: Probing particles smaller than a billionth of a meter", , , Enabling the development and application of minuscule materials in the fields of electronics; biomedicine; chemistry; and more., Nanotechnology, , SNCs-"subnano clusters", Subnanoscale science, Surface plasmon resonance, Surface-enhanced Raman spectroscopy,   

    From Tokyo Institute of Technology- “Nanoscience breakthrough: Probing particles smaller than a billionth of a meter” 

    tokyo-tech-bloc

    From Tokyo Institute of Technology

    December 16, 2019

    Professor Kimihisa Yamamoto
    Institute of Innovative Research,
    Tokyo Institute of Technology
    Email yamamoto@res.titech.ac.jp
    Tel +81-45-924-5260

    Contact
    Public Relations Section, Tokyo Institute of Technology
    Email media@jim.titech.ac.jp
    Tel +81-3-5734-2975

    Scientists at Tokyo Institute of Technology (Tokyo Tech) developed a new methodology that allows researchers to assess the chemical composition and structure of metallic particles with a diameter of only 0.5 to 2 nm. This breakthrough in analytical techniques will enable the development and application of minuscule materials in the fields of electronics, biomedicine, chemistry, and more.

    1
    Figure: A schematic diagram of the direct detection of subnano clusters.

    Tin oxide SNCs finely prepared by a dendrimer template method are loaded on the thin silica shell layers of plasmonic amplifiers, such that the Raman signals of the SNCs are substantially enhanced to a detectable level. The strength of the electromagnetic fields generated due to the surface plasmon resonance properties of the Au or Ag nanoparticles decays exponentially with distance from the surface. Therefore, a rational interfacial design between the amplifiers and SNCs is the key to acquiring strong Raman signals.

    The study and development of novel materials have enabled countless technological breakthroughs and are essential across most fields of science, from medicine and bioengineering to cutting-edge electronics. The rational design and analysis of innovative materials at nanoscopic scales allows us to push through the limits of previous devices and methodologies to reach unprecedented levels of efficiency and new capabilities. Such is the case for metal nanoparticles, which are currently in the spotlight of modern research because of their myriad potential applications. A recently developed synthesis method using dendrimer molecules as a template allows researchers to create metallic nanocrystals with diameters of 0.5 to 2 nm (billionths of a meter). These incredibly small particles, called “subnano clusters” (SNCs), have very distinctive properties, such as being excellent catalyzers for (electro)chemical reactions and exhibiting peculiar quantum phenomena that are very sensitive to changes in the number of constituent atoms of the clusters.

    Unfortunately, the existing analytic methods for studying the structure of nanoscale materials and particles are not suitable for SNC detection. One such method, called Raman spectroscopy, consists of irradiating a sample with a laser and analyzing the resulting scattered spectra to obtain a molecular fingerprint or profile of the possible components of the material. Although traditional Raman spectroscopy and its variants have been invaluable tools for researchers, they still cannot be used for SNCs because of their low sensitivity. Therefore, a research team from Tokyo Tech, including Dr. Akiyoshi Kuzume, Prof. Kimihisa Yamamoto and colleagues, studied a way to enhance Raman spectroscopy measurements and make them competent for SNC analysis (Figure).

    One particular type of Raman spectroscopy approach is called surface-enhanced Raman spectroscopy. In its more refined variant, gold and/or silver nanoparticles enclosed in an inert thin silica shell are added to the sample to amplify optical signals and thus increase the sensitivity of the technique. The research team first focused on theoretically determining their optimal size and composition, where 100-nm silver optical amplifiers (almost twice the size commonly used) can greatly amplify the signals of the SNCs adhered to the porous silica shell. “This spectroscopic technique selectively generates Raman signals of substances that are in close proximity to the surface of the optical amplifiers,” explains Prof. Yamamoto. To put these findings to test, they measured the Raman spectra of tin oxide SNCs to see if they could find an explanation in their structural or chemical composition for their inexplicably high catalytic activity in certain chemical reactions. By comparing their Raman measurements with structural simulations and theoretical analyses, they found new insights on the structure of the tin oxide SNCs, explaining the origin of atomicity-dependent specific catalytic activity of tin oxide SNCs.

    The methodology employed in this research could have great impact on the development of better analytic techniques and subnanoscale science. “Detailed understanding of the physical and chemical nature of substances facilitates the rational design of subnanomaterials for practical applications. Highly sensitive spectroscopic methods will accelerate material innovation and promote subnanoscience as an interdisciplinary research field,” concludes Prof. Yamamoto. Breakthroughs such as the one presented by this research team will be essential for broadening the scope for the application of subnanomaterials in various fields including biosensors, electronics, and catalysts.

    Reference
    Authors :
    Akiyoshi Kuzume1, Miyu Ozawa2, Yuansen Tang2, Yuki Yamada2, Naoki Haruta1, Kimihisa Yamamoto1,2
    Title of original paper : Ultrahigh sensitive Raman spectroscopy for subnanoscience: Direct observation of tin oxide clusters
    Journal : Science Advances, 5, eaax6455 (2019)

    See the full article for other references with links.

    See the full article here .

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    tokyo-tech-campus

    Tokyo Tech is the top national university for science and technology in Japan with a history spanning more than 130 years. Of the approximately 10,000 students at the Ookayama, Suzukakedai, and Tamachi Campuses, half are in their bachelor’s degree program while the other half are in master’s and doctoral degree programs. International students number 1,200. There are 1,200 faculty and 600 administrative and technical staff members.

    In the 21st century, the role of science and technology universities has become increasingly important. Tokyo Tech continues to develop global leaders in the fields of science and technology, and contributes to the betterment of society through its research, focusing on solutions to global issues. The Institute’s long-term goal is to become the world’s leading science and technology university.

     
  • richardmitnick 1:36 pm on December 10, 2019 Permalink | Reply
    Tags: "Meet the microorganism that likes to eat meteorites", , , , , , , For this study the researchers ran tests on material from a meteorite labeled Northwest Africa 1172 (NWA 1172)., Nanotechnology, Redox is is a type of chemical reaction in which the oxidation states of atoms are changed and is common in biological processes., The microbe M. sedula,   

    From University of Vienna via EarthSky: “Meet the microorganism that likes to eat meteorites” 

    From University of Vienna

    via

    1

    EarthSky

    December 10, 2019
    Paul Scott Anderson

    At least one type of microbe on Earth not only likes to eat meteorites but actually prefers them as a food source, according to a new international scientific study.

    1
    Meteorite dust fragments colonized and bioprocessed by the microbe M. sedula. Image via Tetyana Milojevic/ Universität Wien.

    You’ve gotta eat to live. That’s a truism not just for humans but for other lifeforms, including microbes. Now an international team of scientists has announced a new study, showing that at least one type of earthly bacteria has a fondness for extraterrestrial food: meteorites, or rocks from space. These microbes even seem to prefer space rocks to their usual earthly fare of earthly rocks.

    The intriguing peer-reviewed results were published in Nature Scientific Reports on December 2, 2019.

    Astrobiologist Tetyana Milojevic of the University of Vienna in Austria led the research, which demonstrated that an ancient single-celled bacteria known as Metallosphaera sedula (M. sedula) can not only process material in meteorites for food, but will even colonize meteorites faster than earthly rocks.

    M. sedula belong to a family of bacteria known as lithotrophs; that is, they derive their energy from inorganic sources. The term “lithotroph” was created from the Greek terms ‘lithos’ (rock) and ‘troph’ (consumer), meaning “eaters of rock.”

    For this study, the researchers ran tests on material from a meteorite labeled Northwest Africa 1172 (NWA 1172). They found that the microbes colonized the material much more quickly than they would terrestrial material.

    3
    Graphic showing the ingestion of inorganic material by the microbe M. sedula in the meteorite NWA 1172. Image via Tetyana Milojevic/ Universität Wien.

    As Milojevic said in a statement:

    “Meteorite-fitness seems to be more beneficial for this ancient microorganism than a diet on terrestrial mineral sources. NWA 1172 is a multimetallic material, which may provide much more trace metals to facilitate metabolic activity and microbial growth. Moreover, the porosity of NWA 1172 might also reflect the superior growth rate of M. sedula.”

    This is certainly interesting, suggesting that M. sedula actually prefers the material coming from space over its local, home-grown, earthly food sources.

    4
    Scanning electron microscope image of meteorite NWA 1172, showing colonization of M. sedula microbes. Image via Tetyana Milojevic/ Universität Wien/ Daily Mail.

    So how did the scientists make these findings?

    “They examined the meteorite-microbial interface at nanometer scale – one billionth of a meter – and traced how the material was consumed, investigating the iron redox behavior. Redox is is a type of chemical reaction in which the oxidation states of atoms are changed, and is common in biological processes. By combining several analytical spectroscopy techniques with transmission electron microscopy, they found a set of biogeochemical fingerprints left upon M. sedula growth on the meteorite. As Milojevic explained:

    Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry.”

    See the full article here .

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    The University of Vienna (German: Universität Wien) is a public university located in Vienna, Austria. It was founded by Duke Rudolph IV in 1365 and is one of the oldest universities in the German-speaking world. With its long and rich history, the University of Vienna has developed into one of the largest universities in Europe, and also one of the most renowned, especially in the Humanities. It is associated with 15 Nobel prize winners and has been the academic home to a large number of scholars of historical as well as of academic importance.

     
  • richardmitnick 11:08 am on December 9, 2019 Permalink | Reply
    Tags: , INFLUENCING NANOSCALE INSTRUMENTATION, Maya Lassiter, Nanotechnology, ,   

    From Penn Today: Women in STEM- “When Curiosity Meets Nano Device Fabrication” Maya Lassiter 


    From Penn Today

    Nov 21, 2019 [Just now in social media]

    1
    Maya Lassiter

    Experiencing the democratization of media through third-party applications like LimeWire, YouTube and MySpace may have influenced the perspective and career trajectory of a woman who wants to impact the process of nanofabrication.

    “I lived through the CD-to-iPod-to-iPhone progression and felt that computers and technology could be a means by which to increase expression and understanding. That probably has a lot to do with my fascination with electrical and computer engineering,” says Maya Lassiter, doctoral GEM Fellow in the Department of Electrical and Systems Engineering at Penn Engineering.

    At Penn, Lassiter is applying an instrumentation and systems perspective to understand how nanoscale robots can be fabricated, controlled and used to further biological research. Along the way she hopes to inform the practice of creating devices from a holistic understanding of design, resource use and application.

    INFLUENCING NANOSCALE INSTRUMENTATION

    “I am interested in what nanoscale instrumentation can uncover regarding cell behavior and tissue dynamics, and how they affect larger systems,” says Lassiter. “I hope to create devices that have rhyme and reason — such as a clear rationale for materials use. As we advance the science of nanofabrication, we should introduce manufacturing processes and creative solutions that are much broader than those currently being implemented. Those changes can be changes for the better, and I want to be part of that.”

    Ultimately, she also wants her research to help further the understanding of how biological systems work in order to engineer nanoscale instrumentation that works with the systems, not against them. “I am especially interested in developing non-destructive devices for neural systems so our attempts to engage with specific cells do not come at the expense of harming the surrounding tissue.”

    TAKING A HOLISTIC FOCUS ON TECHNOLOGY

    Lassiter, who earned her BS and MS degrees in Electrical and Computer Engineering and was named the Outstanding Woman in Engineering at Carnegie Mellon University, was excited to continue her education at Penn Engineering for a number of reasons. “I get to work in the Singh Center for Nanotechnology, an exciting facility with world-class technical staff. Plus, I have the resource of Penn Engineering’s faculty who are at the frontier of science and technology,” she says. “Philadelphia is a well-connected city and a great place to be a graduate student. Coming from Pittsburgh, I am glad to experience another part of the state, where there is an active art and broader city culture that I want to get to know!”

    Lassiter is a GEM Fellow, part of the National GEM Consortium that is dedicated to enhancing the value of the nation’s human capital by increasing the participation of underrepresented groups (African Americans, American Indians, and Hispanic Americans) at the master’s and doctoral levels in engineering and science. “I believe I have something to offer in the creation of technology,” she says. “My long-term goal is to change how we think about community in engineering. I am not sure about the path to get there, but my next step will be to make work that conveys a holistic understanding of technology.

    See the full article here .

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    U Penn campus

    Academic life at Penn is unparalleled, with 100 countries and every U.S. state represented in one of the Ivy League’s most diverse student bodies. Consistently ranked among the top 10 universities in the country, Penn enrolls 10,000 undergraduate students and welcomes an additional 10,000 students to our world-renowned graduate and professional schools.

    Penn’s award-winning educators and scholars encourage students to pursue inquiry and discovery, follow their passions, and address the world’s most challenging problems through an interdisciplinary approach.

     
  • richardmitnick 5:59 pm on November 30, 2019 Permalink | Reply
    Tags: , , Black phosphorus, , , Chromium triiodide, , , Nanotechnology, Phosphorene, ,   

    From Discover Magazine: “Move over Graphene: Next-Gen 2D Materials Could Revolutionize Technology” 

    DiscoverMag

    From Discover Magazine

    November 29, 2019
    John Wenz

    Move over, flat carbon. Meet borophene, phosphorene and the rest of the next generation of “atomically thin” super-materials.

    1
    An illustration of graphene’s hexagonal molecular structure. (Credit: OliveTree/Shutterstock)

    The wonder material graphene — an array of interlinked carbon atoms arranged in a sheet just one atom thick — promised a world of applications, including super-fast electronics, ultra-sensitive sensors and incredibly durable materials. After a few false starts, that promise is close to realization. And a suite of other extremely thin substances is following in its wake.

    Graphene got its beginnings in 2003, when scientists at the University of Manchester found they could peel off a gossamer film of the material just by touching a piece of ordinary sticky tape to a block of purified graphite — the solid form of carbon that’s mixed with clay and used as the “lead” in most pencils. Graphene proved stronger than steel but extremely flexible, and electrons could zip through it at high speeds. It earned its discoverers the Nobel Prize in 2010, but researchers spent years struggling to manufacture it on larger scales and figuring out how its remarkable properties could best be used.

    They didn’t get it right straight out of the gate, says Todd Krauss, a chemist at the University of Rochester. “Scientists are pretty bad at predicting what’s going to be useful in applications,” he says.

    With its atom-thin sheets layered into tiny particles known as quantum dots, graphene was tried as a microscopic medical sensor, but it didn’t perform as desired, Krauss says. With its sheets rolled up into straw-like nanotubes, graphene was built into items like hockey sticks and baseball bats in the hopes that its strength and durability could better existing carbon fiber. But Krauss notes that there has since been a trend away from using nanotubes in consumer products. (Some also worry that long carbon nanotubes could harm the lungs since they have been shown to have some chemical resemblance to asbestos.)

    Today graphene is finding its way into different types of products. “Graphene is here,” says Mark Hersam of Northwestern University. Layered over zinc, graphene oxide is actively being developed as a replacement, with higher storage capacity, for the sometimes unreliable graphite now used in battery anodes. And nanotubes were recently used as transistors to build a microprocessor, replacing silicon (unlike flat graphene, nanotubes can be coaxed into acting like a semiconductor). Though the microprocessor was primitive by modern computing standards, akin to the processing level of a Sega Genesis, materials scientists think it could ultimately pave the way for more efficient, faster and smaller carbon components for computer processors.

    At the same time, a new generation of two-dimensional materials is emerging. The success of graphene further fueled the ongoing effort to find useful atomically thin materials, working with a range of different chemicals, so as to exploit the physical properties that emerge in such super-thin substances. The newcomers include an insulator more efficient than conventional ones at stopping the movement of electrons, and another that allows electrons to glide across it at a good percent of the speed of light, with little friction. Researchers think some of these may one day replace silicon in computer chips, among other potential uses.

    Other materials now in development have even higher aspirations, such as advancing scientists toward one of the most tantalizing goals in chemistry — the creation of high-temperature superconductors.

    Speedy Electrons

    In graphene, carbon atoms link up in an orderly honeycomb pattern, each atom sharing electrons with three neighboring carbon atoms. That structure allows any added electrons to move speedily across its surface. Ordinarily, a single electron might move through a conducting metal like copper at 1.2 inches per minute (given a 12-gauge wire with 10 amps of electricity). But in early experiments on graphene, electrons zipped along at 2.34 billion inches per minute — which could make for electronics that charge in just a few minutes and eventually in a matter of seconds.

    Graphene’s physical properties have inspired many potential applications, including in medicine. A variant of graphene, graphene oxide, is being studied as an experimental drug delivery vehicle. Seen here through a microscope, this chunk of graphene oxide is about 80 nanometers high. A single sheet of graphene is just 0.34 nanometers thick.

    Graphene conducts heat just as well as it conducts electricity. It’s also one of the strongest materials ever studied — stronger than steel, it can stop a bullet — but oddly stretchy too, meaning it’s both flexible and tough.

    Other 2D materials under exploration may have similar attributes as well as novel qualities all their own, but chemical impurities have until recently kept them hidden, says Angela Hight Walker, a project leader at the National Institute of Standards and Technology in Gaithersburg, Maryland. “We’re now getting to the point where we can see the new physics that’s been covered up by poor sample quality,” she says.

    One of the newcomers is black phosphorus, explored by Hersam and his coauthor Vinod Sangwan in the 2018 Annual Review of Physical Chemistry. When white phosphorus — a caustic, highly reactive chemical — is super-heated under high pressure, it becomes a flaky, conductive material with graphite-like behavior. Peeling off an atom-thin layer of this black phosphorus with sticky tape produces a material called phosphorene. First fabricated in 2014, phosphorene rivals graphene in terms of strength and ability to efficiently move electrons. But at the atomic level, it isn’t as perfectly flat as graphene — and that has intriguing consequences.

    Phosphorene interacts with electrons and photons in quirky ways, pointing to potential uses in future computer chips and fiber optics.

    In graphene, carbon atoms lie side by side, hence its flatness. But phosphorene’s 2D configuration looks a bit like a pleat, with two atoms at a lower level connected to two at a higher level, forming what’s called a bandgap. This wavy structure, in turn, affects the flow of electrons in a way that makes phosphorene a “semiconductor,” meaning that it’s very easy to switch the flow of electrons on or off. Phosphorene, like silicon, could find application in computer chips, where the toggled electrons represent 1s or 0s.

    Phosphorene also is especially good at emitting or absorbing photons at infrared wavelengths. This optical trick gives phosphorene huge potential for use in fiber-optic communication, Hersam says, because the bandgap matches the energy of infrared light near-exactly. It could also prove very useful in solar cells.

    Working with phosphorene is not easy, however. It is highly unstable and rapidly oxidizes unless stored correctly. “Literally, it will decompose if it is sitting out in the room,” Hight Walker says, typically in less than a minute. Layering it with other 2D materials could help protect the fragile chemical.

    Two Sides of Boron

    Boron would seem an odd fit for electronic applications. It’s better known as a fertilizer, an ingredient in fiberglass or (combined with salt) a laundry-detergent additive. But make it very thin and very flat, and boron begins to act more like a metal, conducting electricity easily. Two-dimensional boron, called borophene, is also ultra-flexible and transparent. Combined with its conductive properties, borophene’s flexibility and transparency could eventually make it a go-to material for new gadgets, including ultra-thin, foldable touch screens.

    Like graphene, borophene’s structure allows electrons to fly through it. It’s such a good conductor that it’s now being studied as a way to boost energy storage in lithium-ion batteries. Some researchers even think it might be coaxed into superconducting states at relatively high temperatures — though that’s still very cold (initial tests show the effect between minus-415 to minus-425 degrees Fahrenheit). Most current superconductors work close to absolute zero, or nearly minus -460 degrees F. A superconducting material allows electrons to move through it without any resistance, creating the potential for a device that accomplishes robust electronic feats while using only a small amount of power.

    3
    Emerging 2D materials phosphorene, borophene and boron nitride form thin films. Their atomic arrangements are viewed here from above and in profile. (Credit: Modified from V.K. Sangwan and M.C. Hersam/AR Physical Chemistry 2018)

    In the form of borophene, boron can conduct electrons like a metal. Yet, as part of a 2D-film of boron nitride, it can block the flow of electrons quite effectively. “In other words, 2D boron and [2D] boron nitride are on opposite ends of the electrical conductivity spectrum,” Hersam says.

    Boron nitride’s insulative property has come in handy for research on other 2D materials. Take that ephemeral black phosphorus: One way scientists have managed to keep it stable enough to study is by sandwiching it between two sheets of boron nitride.

    Even as it is blocking electrons, however, boron nitride will allow photons to pass, says physicist Milos Toth of the University of Technology Sydney, who coauthored an article about the potential of boron nitride, and other 2D materials, in the 2019 Annual Review of Physical Chemistry. That’s ideal for creating things called single-photon sources, which can emit a single particle of light at a time and are used in quantum computing, quantum information processing and physics experiments.

    Magnetic Material

    Another atomically thin material creating quite a buzz in materials science circles is a compound of chromium and iodine called chromium triiodide. It’s the first 2D material that naturally generates a magnetic field. Scientists working on chromium triiodide propose the material could eventually find uses in computer memory and storage, as well as in more research-focused purposes such as controlling how an electron spins.

    There’s a hitch, Hersam says: “This material is extremely hard to work with,” because it is both tough to synthesize and unstable once it’s made. Right now the only way to work with it is at extremely low temperatures, at minus-375 degrees Fahrenheit and below. But boron nitride might again come to the rescue: Some chromium triiodide samples have been preserved for months on end inside boron nitride sandwiches.

    Because of its finicky properties, chromium triiodide may not itself end up built into devices, Hight Walker says. “But when we understand the physics of what’s happening, we can go look for this 2D magnetic behavior in other materials.” A number of 2D magnetic materials are now being explored — single-layer manganese crystals woven into an insulating material is one possibility.

    Thin Sandwichesere

    Wrangling any of these thin layers into something usable may ultimately depend — literally — on how they stack up. Different super-thin materials would be layered together so that the properties inherent in each material can complement one another. “We have insulators, semiconductors, metals and now magnets,” Hight Walker says. “Those are the pieces that you need to make almost anything you want.”

    One potential application especially exciting to Hight Walker is in quantum computing. Unlike traditional computing, in which bits of information are either ones or zeroes, quantum computing allows each “qubit” of information to be both one and zero at once. In principle, this would allow quantum computers to quickly solve problems that would take an impossibly long time with conventional machines.

    Right now, though, most qubits are made of superconductors that have to be kept freezing cold, limiting their real-world use and motivating the search for new types of superconducting materials. For this reason, researchers are eager to explore borophene’s ability to superconduct. (Graphene, layered a certain way, also has shown potential superconducting properties.)

    But a stacked material involving several superconducting layers separated by strong insulators could enable smaller, more stable qubits that don’t require quite as low temperatures — which could reduce the overall size of quantum computers. Right now, these are room-sized affairs, much like early computers were. Reducing their size is going to require novel approaches and, possibly, very thin materials — layered sheet by little sheet.

    See the full article here .

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  • richardmitnick 9:45 am on November 22, 2019 Permalink | Reply
    Tags: , , , Nanotechnology,   

    From Brookhaven National Lab: “Turning Up the Heat to Create New Nanostructured Metals” 

    From Brookhaven National Lab

    November 20, 2019
    Ariana Manglaviti
    amanglaviti@bnl.gov
    (631) 344-2347

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

    Scientists used heat to drive a spontaneous process in which different metals mixed to form 3-D interlocking nanostructures in thin films, with applications for catalysts, solar cells, and biomedical sensors.

    1
    Kim Kisslinger, Karen Chen-Wiegart, Bruce Ravel, Xiaojing Huang, Fernando Camino, Yong Chu, Hanfei Yan, Ming Lu, Chonghang Zhao, Cheng-Hung Lin, Mingzhao Liu, and Evgeny Nazaretski outside Brookhaven Lab’s Center for Functional Nanomaterials (CFN). The scientists used the Nanofabrication and Electron Microscopy facilities at the CFN and the Hard X-ray Nanoprobe and Beamline for Materials Measurement at the National Synchrotron Light Source II (pictured in the background) to synthesize and characterize metallic thin films with a bicontinuous structure formed via dealloying.

    Scientists have developed a new approach for making metal-metal composites and porous metals with a 3-D interconnected “bicontinuous” structure in thin films at size scales ranging from tens of nanometers to microns. Metallic materials with this sponge-like morphology—characterized by two coexisting phases that form interpenetrating networks continuing over space—could be useful in catalysis, energy generation and storage, and biomedical sensing. Called thin-film solid-state interfacial dealloying (SSID), the approach uses heat to drive a self-organizing process in which metals mix or de-mix to form a new structure. The scientists used multiple electron- and x-ray-based techniques (“multimodal analysis”) to visualize and characterize the formation of the bicontinuous structure.

    “Heating gives the metals some energy so that they can interdiffuse and form a self-supported thermodynamically stable structure,” explained Karen Chen-Wiegart, an assistant professor in Stony Brook University’s (SBU) Materials Science and Chemical Engineering Department, where she leads the Chen-Wiegart Research Group, and a scientist at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at Brookhaven National Laboratory. “SSID has been previously demonstrated in bulk samples (tens of microns and thicker) but results in a size gradient, with a larger structure on one side of the sample and a smaller structure on the other side. Here, for the first time, we successfully demonstrated SSID in a fully integrated thin-film processing, resulting in a homogenous size distribution across the sample. This homogeneity is needed to create functional nanostructures.”

    Chen-Wiegart is the corresponding author on a paper published online in Materials Horizons that is featured on the Nov. 18 online journal issue cover. The other collaborating institutions are the Center for Functional Nanomaterials (CFN)—another DOE Office of Science User Facility at Brookhaven Lab—and the National Institute of Standards and Technology (NIST).

    To demonstrate their process, the scientists prepared magnesium (Mg) and iron (Fe) and nickel (Ni) alloy thin films on silicon (Si) wafer substrates in the CFN Nanofabrication Facility. They heated the samples to high temperature (860 degrees Fahrenheit) for 30 minutes and then rapidly cooled them down to room temperature.

    “We found that Mg diffuses into the Fe-Ni layer, where it combines only with Ni, while Fe separates from Ni,” said first author Chonghang Zhao, a PhD student in the Chen-Wiegart Research Group. “This phase separation is based on enthalpy, an energy measurement that determines whether the materials are “happily” mixing or not, depending on properties such as their crystal structure and bonding configurations. The nanocomposite can be further treated to generate a nanoporous structure through chemically removing one of the phases.”

    2
    A schematic showing thin-film SSID for the Fe-Ni/Mg system. The thin films of Mg and Fe-Ni are layered on top of an Si substrate. Upon exposure to heat, the Mg dealloys Fe-Ni to form an Mg-Ni composite and pure Fe with a 3-D bicontinuous structure.

    Nanoporous structures have many applications, including photocatalysis. For example, these structures could be used to accelerate the reaction in which water is split into oxygen and hydrogen—a clean-burning fuel. Because catalytic reactions happen on material surfaces, the high surface area of the pores would improve reaction efficiency. In addition, because the nanosized “ligaments” are inherently interconnected, they do not need any support to hold them together. These connections could provide electrically conductive pathways.

    The team identified the dealloyed bicontinuous structure of Fe and Ni-Mg through complementary electron microscopy techniques at the CFN and x-ray synchrotron techniques at two NSLS-II beamlines: the Hard X-ray Nanoprobe (HXN) and Beamline for Materials Measurement (BMM).

    “Using the scanning mode in a transmission electron microscope (TEM), we rastered the electron beam over the sample in specific locations to generate 2-D elemental maps showing the spatial distribution of elements,” explained Kim Kisslinger, a technical associate in the CFN Electron Microscopy research group and the point of contact for the instrument.

    3
    The scientists used a scanning transmission electron microscope (STEM) to study the structure and composition of Fe-Ni films dealloyed by an Mg film. In particular, they combined high-angle annular dark-field (HAADF) imaging with energy-dispersive x-ray spectroscopy (EDS). HAADF imaging is sensitive to the atomic number of elements in the sample. Elements with a higher atomic number scatter more electrons, causing them to appear brighter in the resulting greyscale image. For the EDS maps, the different colors correspond to individual elements and the color intensity to their local relative concentration. STEM analysis revealed the formation of two phases: pure Fe (magenta) and an Ni-Mg (yellow-purple) composite.

    The team also used TEM to obtain electron diffraction patterns capturing the crystal structure and a scanning electron microscope (SEM) to study surface morphology.

    This initial analysis provided evidence of the formation of a bicontinuous structure locally in 2-D at high resolution. To further confirm that the bicontinuous structure was representative of the entire sample, the team turned to HXN beamline, which can provide 3-D information over a much larger region.

    “With HXN, we can focus hard, or high-energy, x-rays to a very tiny spot of about 12 nanometers,” said coauthor and HXN physicist Xiaojing Huang. “The world-leading spatial resolution of hard x-ray microscopy at HXN is sufficient to see the sample’s smallest structures, which range in size from 20 to 30 nanometers. Though TEM provides higher resolution, the field of view is limited. With the x-ray microscope, we were able to observe the 3-D element distributions within a bigger area so that we could confirm the homogeneity.”

    Measurements at HXN were conducted in a multimodality manner, with the simultaneous collection of x-ray scattering signals that reveal 3-D structure and fluorescence signals that are element-sensitive. Atoms emit fluorescence when they jump back to their lowest-energy (ground) state after being excited to an unstable higher-energy state in response to the x-ray energy. By detecting this characteristic fluorescence, scientists can determine the type and relative abundance of elements present at specific locations.


    A video based on the 3-D x-ray fluorescence nanotomography of the Fe-Ni thin film conducted at the Hard X-ray Nanoprobe.

    Coauthor and NIST Synchrotron Science Group physicist Bruce Ravel confirmed the sample’s chemical composition and obtained the precise chemical forms (oxidation states) of the elements at BMM, which is funded and operated by NIST. The x-ray absorption near-edge structure (XANES) spectra also showed the presence of pure Fe.

    Now that the scientists have shown that SSID works in thin films, their next step is to address the “parasitic” events they identified in the course of this study. For example, they discovered that Ni diffuses into the Si substrate, leading to voids, a kind of structural defect. They will also make pore structures from the metal-metal composites to demonstrate applications such as photocatalysis, and apply their approach to other metal systems, including titanium-based ones.

    This work was in part supported by a student fellowship by the Brookhaven-SBU Joint Photon Sciences Institute and the National Science Foundation’s Faculty Early Career Development Program and Metals and Metallic Nanostructures Program.

    See the full article here .


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    Please help promote STEM in your local schools.

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    BNL Campus


    BNL Center for Functional Nanomaterials

    BNL NSLS-II


    BNL NSLS II

    BNL RHIC Campus

    BNL/RHIC Star Detector

    BNL RHIC PHENIX

    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 3:41 pm on November 12, 2019 Permalink | Reply
    Tags: "SMART discovers nondisruptive way to characterize the surface of nanoparticles", , , , , Nanotechnology   

    From MIT News: “SMART discovers nondisruptive way to characterize the surface of nanoparticles” 

    MIT News

    From MIT News

    November 12, 2019
    Singapore-MIT Alliance for Research and Technology

    New method overcomes limitations of existing chemical procedures and may accelerate nanoengineering of materials.

    1
    Schematic illustration of probe adsorption influenced by an attractive interaction within the corona.

    Researchers from the Singapore-MIT Alliance for Research and Technology (SMART) have made a discovery that allows scientists to “look” at the surface density of dispersed nanoparticles. This technique enables researchers to understand the properties of nanoparticles without disturbing them, at a much lower cost and far more quickly than with existing methods.

    The new process is explained in a paper entitled “Measuring the Accessible Surface Area within the Nanoparticle Corona using Molecular Probe Adsorption,” published in the academic journal Nano Letters. It was led by Michael Strano, co-lead principal investigator of the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) research group at SMART and the Carbon P. Dubbs Professor at MIT, and MIT graduate student Minkyung Park. DiSTAP is a part of SMART, MIT’s research enterprise in Singapore, and develops new technologies to enable Singapore, a city-state which is dependent upon imported food and produce, to improve its agriculture yield to reduce external dependencies.

    The molecular probe adsorption (MPA) method is based on a noninvasive adsorption of a fluorescent probe on the surface of colloidal nanoparticles in an aqueous phase. Researchers are able to calculate the surface coverage of dispersants on the nanoparticle surface — which are used to make it stable at room temperature — by the physical interaction between the probe and nanoparticle surface.

    “We can now characterize the surface of the nanoparticle through its adsorption of the fluorescent probe. This allows us to understand the surface of the nanoparticle without damaging it, which is, unfortunately, the case with chemical processes widely used today,” says Park. “This new method also uses machines that are readily available in labs today, opening up a new, easy method for the scientific community to develop nanoparticles that can help revolutionize different sectors and disciplines.”

    The MPA method is also able to characterize a nanoparticle within minutes compared to several hours that the best chemical methods require today. Because it uses only fluorescent light, it is also substantially cheaper.

    DiSTAP has started to use this method for nanoparticle sensors in plants and nanocarriers for delivery of molecular cargo into plants.

    “We are already using the new MPA method within DiSTAP to aid us in creating sensors and nanocarriers for plants,” says Strano. “It has enabled us to discover and optimize more sensitive sensors and understand the surface chemistry, which in turn allows for greater precision when monitoring plants. With higher-quality data and insight into plant biochemistry, we can ultimately provide optimal nutrient levels or beneficial hormones for healthier plants and higher yields.”

    See the full article here .


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    Please help promote STEM in your local schools.


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    MIT Seal

    The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the twenty-first century. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

    MIT Campus

     
  • richardmitnick 12:54 pm on November 6, 2019 Permalink | Reply
    Tags: "Engineers Create Tiny 'Artificial Sunflowers' That Bend Towards The Light", , , Heliotropism, Nanotechnology, , SunBOTs, The research team looked to gels and polymers that respond predictably to light or heat.,   

    From UCLA and From Arizona State University via Science Alert: “Engineers Create Tiny ‘Artificial Sunflowers’ That Bend Towards The Light” 

    UCLA bloc

    From UCLA

    and

    ASU Bloc

    From Arizona State University

    via

    ScienceAlert

    Science Alert

    6 NOV 2019
    MIKE MCRAE

    1
    (Qian et al., Nature Nanotechnology, 2019)

    When it comes to squeezing maximum amounts of energy out of the daylight hours, plants have a head start thanks to evolution.

    Now, engineers have designed solar panels that mimic the sunflower’s sun-chasing talent, through clever use of nanotechnology.

    By moulding temperature-sensitive materials into thin, supportive structures, scientists have come up with tiny ‘stems’ that bend towards a bright light source, providing a moving platform that could dramatically improve the efficiency of a range of solar technologies.

    Researchers from the University of California Los Angeles and Arizona State University refer to their system as a sunflower-like biomimetic omnidirectional tracker. Or ‘SunBOT’, if you like your acronyms.

    In biological terms, any general movement in response to specific changes in the environment is described as a nastic behaviour. Flowers that open at dawn and close at dusk are a good example of this.

    Chemists have had little trouble making synthetic nastic materials [International Journal of Smart and Nano Materials] and structures that open and close, or bend and twist in response to changes in light intensity or fluctuating temperatures.

    But nature has another, slightly more complicated behaviour that directs the movements of organisms towards good things and away from threats.

    These tropic behaviours are what we see when sunflowers tilt their flowers to face the Sun, warming their reproductive bits [Science ABC] in order to attract pollinators.

    Sun-chasing actions, or heliotropism, would be mighty handy for things like photovoltaics, which are most efficient when bathed in a dense glow of radiation hitting their surface straight-on, rather than from a more shallow angle.

    In practical terms, compared to rays from an overhead illumination source, light coming in at an angle of around 75 degrees carries as much as 75 percent less energy.

    To solve this problem of oblique-incidence energy-density loss, the research team looked to gels and polymers that respond predictably to light or heat.

    A handful of different materials were selected as candidates worth closer investigation, including a hydrogel containing gold nanoparticles, a tangle of light-sensitive polymers, and a type of liquid crystalline elastomer embedded with a light-absorbing dye.

    Each arrangement was shaped into a millimetre-wide thread several centimetres in length. When targeted by a laser, the tiny artificial stalks responded rapidly to the light’s warmth, shrinking on one side and expanding on the other to cause the thread to kink and lean towards the laser.

    To put their synthetic sunflowers to the test, the researchers assembled an array of SunBOTs and submerged them in water, letting them sit right at the water-air boundary.

    To detect the harvesting capabilities of their invention, the team then determined how much light was converted to heat by measuring the water vapour their setup generated.

    Changes in the amount of vapour indicated that the SunBOTs were up to four times better at harvesting energy at steep angles than a boring old flat, static surface.

    By demonstrating that a variety of materials could serve as a synthetic tropic material, the researchers argue their devices could potentially be a solution for just about any system that experiences a loss of efficiency due to a moving energy source.

    For example, lawns of these miniature sun-worshippers could theoretically be used to tilt just about any solar process towards the light, from itty-bitty solar cells to evaporation devices that can purify water.

    According to the SunBOTs’ designers, the sky (if not beyond!) seems to be the limit for this kind of technology.

    “This work may be useful for enhanced solar harvesters, adaptive signal receivers, smart windows, self-contained robotics, solar sails for spaceships, guided surgery, self-regulating optical devices, and intelligent energy generation (for example, solar cells and biofuels), as well as energetic emission detection and tracking with telescopes, radars and hydrophones,” they write in their report.

    Even if just a handful of those predictions eventuates into real-world use, the future of synthetic tropic materials is certainly looking brighter.

    This research was published in Nature Nanotechnology.

    See the full article here .

    five-ways-keep-your-child-safe-school-shootings

    Please help promote STEM in your local schools.

    Stem Education Coalition

    ASU is the largest public university by enrollment in the United States. Founded in 1885 as the Territorial Normal School at Tempe, the school underwent a series of changes in name and curriculum. In 1945 it was placed under control of the Arizona Board of Regents and was renamed Arizona State College. A 1958 statewide ballot measure gave the university its present name.
    ASU is classified as a research university with very high research activity (RU/VH) by the Carnegie Classification of Institutions of Higher Education, one of 78 U.S. public universities with that designation. Since 2005 ASU has been ranked among the Top 50 research universities, public and private, in the U.S. based on research output, innovation, development, research expenditures, number of awarded.

    UC LA Campus

    For nearly 100 years, UCLA has been a pioneer, persevering through impossibility, turning the futile into the attainable.

    We doubt the critics, reject the status quo and see opportunity in dissatisfaction. Our campus, faculty and students are driven by optimism. It is not naïve; it is essential. And it has fueled every accomplishment, allowing us to redefine what’s possible, time after time.

    This can-do perspective has brought us 12 Nobel Prizes, 12 Rhodes Scholarships, more NCAA titles than any university and more Olympic medals than most nations. Our faculty and alumni helped create the Internet and pioneered reverse osmosis. And more than 100 companies have been created based on technology developed at UCLA.

     
  • richardmitnick 11:33 am on November 4, 2019 Permalink | Reply
    Tags: "Copper could help unlock the clean-energy potential of hydrogen fuel cells", , , , , , Nanotechnology   

    From JHU HUB: “Copper could help unlock the clean-energy potential of hydrogen fuel cells” 

    Johns Hopkins

    From JHU HUB

    11.1.19
    Lisa Ercolano
    Matthew Chin

    Hydrogen fuel cells may someday power automobiles and trucks, offering a source of energy that’s free of carbon emissions and pollutants. But their potential has been limited thus far by the high cost and instability of the platinum-nickel catalyst needed to spark the chemical reaction that produces clean electricity.

    Using experiments and computer simulations, materials scientists from Johns Hopkins University and the University of California, Los Angeles have taken a major leap toward making that future possible. Their study, published in Matter, sheds new light on a method of stabilizing catalysts by adding copper and provides details on why the method works.

    1
    Copper in the Periodic Table

    The UCLA team was led by Yu Huang, a professor of materials science and engineering. The Hopkins team was led by Tim Mueller, assistant professor of materials science and engineering.

    “The problem is that platinum-nickel catalysts, which are very promising for use in fuel cells, degrade over time as the nickel dissolves,” explains Mueller, whose research focuses on developing and applying computational methods to allow researchers to understand the real-world behavior of materials and to develop new materials for advanced technologies. “Professor Huang’s group discovered that adding copper to the catalysts helped reduce the amount of nickel dissolution, and our group helped them figure out why, which is important for people who want to build on this research.”

    In experiments, the UCLA researchers found that introducing copper atoms into specially shaped nanoparticles of platinum-nickel resulted in durability that proved to be 40% better, in terms of catalyst efficiency, than those without copper. These new catalysts were very stable—that is, more transition metals were retained in the platinum-nickel-copper particles, despite the corrosive condition that could leach them out. They were also more efficient in catalyzing the chemical reaction, compared to alloys of platinum-nickel and commercially used platinum-carbon.

    To figure out why this was happening, Mueller’s team at Hopkins devised a model based on experimental data and performed computer simulations that revealed how individual atoms moved around the nanoparticles in the type of environment that the catalysts would encounter in a fuel cell.

    “We ran simulations of the particles, both with and without copper, to see how the addition of copper affected the degradation of the particles,” said Liang Cao, a Johns Hopkins postdoctoral scholar of materials science and engineering, and a co-lead author of the study. “We were able to track the particles’ evolution on an atomic scale, and our simulations indicated that the particles that contained copper were more stable because they initially had more platinum on the surface, which protected the nickel and copper atoms from dissolving.”

    According to Huang, the new study is a milestone in understanding the “atomistic structure-function relations in nanoscale materials and opens the door to new design strategies for high-performing nanoscale catalysts.”

    See the full article here .


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    Please help promote STEM in your local schools.

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    About the Hub
    We’ve been doing some thinking — quite a bit, actually — about all the things that go on at Johns Hopkins. Discovering the glue that holds the universe together, for example. Or unraveling the mysteries of Alzheimer’s disease. Or studying butterflies in flight to fine-tune the construction of aerial surveillance robots. Heady stuff, and a lot of it.

    In fact, Johns Hopkins does so much, in so many places, that it’s hard to wrap your brain around it all. It’s too big, too disparate, too far-flung.

    We created the Hub to be the news center for all this diverse, decentralized activity, a place where you can see what’s new, what’s important, what Johns Hopkins is up to that’s worth sharing. It’s where smart people (like you) can learn about all the smart stuff going on here.

    At the Hub, you might read about cutting-edge cancer research or deep-trench diving vehicles or bionic arms. About the psychology of hoarders or the delicate work of restoring ancient manuscripts or the mad motor-skills brilliance of a guy who can solve a Rubik’s Cube in under eight seconds.

    There’s no telling what you’ll find here because there’s no way of knowing what Johns Hopkins will do next. But when it happens, this is where you’ll find it.

    Johns Hopkins Campus
    The Johns Hopkins University opened in 1876, with the inauguration of its first president, Daniel Coit Gilman. “What are we aiming at?” Gilman asked in his installation address. “The encouragement of research … and the advancement of individual scholars, who by their excellence will advance the sciences they pursue, and the society where they dwell.”

    The mission laid out by Gilman remains the university’s mission today, summed up in a simple but powerful restatement of Gilman’s own words: “Knowledge for the world.”

    What Gilman created was a research university, dedicated to advancing both students’ knowledge and the state of human knowledge through research and scholarship. Gilman believed that teaching and research are interdependent, that success in one depends on success in the other. A modern university, he believed, must do both well. The realization of Gilman’s philosophy at Johns Hopkins, and at other institutions that later attracted Johns Hopkins-trained scholars, revolutionized higher education in America, leading to the research university system as it exists today.

     
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