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  • richardmitnick 4:40 pm on January 2, 2018 Permalink | Reply
    Tags: , , , Mallory Ladd, Mallory Ladd began trekking to the Arctic even before her time at the Department of Energy's Oak Ridge National Laboratory, NGEE-Arctic program, ORNL, Soil chemistry,   

    From ORNL: Women in STEM- “Mallory Ladd: A molecular-scale Arctic expedition” 

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    Oak Ridge National Laboratory

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    Mallory Ladd gathers field samples on the coastal plain of northern Alaska. Photo courtesy, Mallory Ladd.

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    Mallory Ladd is a Bredesen Center student working with the NGEE-Arctic program at ORNL, seeking a better understanding of how soil water chemistry affects the aboveground environment. Photo courtesy, Jason Richards

    January 2, 2018

    Stephanie G. Seay, Communications
    seaysg@ornl.gov
    865.576.9894

    Mallory Ladd began trekking to the Arctic, even before her time at the Department of Energy’s Oak Ridge National Laboratory, in search of a better understanding of what’s going on belowground and how it links to changes in the larger landscape.

    The University of Tennessee, Knoxville (UTK) Bredesen Center student last year finished her third trip to Alaska to collect field data for the Next Generation Ecosystem Experiments-Arctic (NGEE-Arctic) program, supported by the U.S. Department of Energy’s Office of Biological and Environmental Research. The program harnesses the expertise of more than 140 scientists from national labs and universities studying how permafrost thaw may affect regional and global climate systems.

    Ladd is using her capabilities in analytical chemistry and mass spectrometry to examine how soil water chemistry is changing in the Arctic because of warming and thawing conditions, in order to better inform earth science models. She has been exploring those changes since her undergraduate days researching Arctic soil nitrogen at the University of Toledo.

    “Chemists usually spend a lot of time in the lab,” Ladd said. “But with this type of research I’m encouraged to get out and collect samples in the field. I feel closer to the science questions that way; working from sample collection to data analysis, from start to finish, has been enlightening.”

    Her path to the Arctic began at Toledo as the result of a chance encounter with Professor Mike Weintraub, who had just received funding from the National Science Foundation (NSF) to examine seasonality in the Arctic. Ladd was a senior at the university at the time, watching a screening of the documentary Dirt! with a friend. “We were talking about how interesting the movie was, how important the nutrient profile and soil chemistry are to so many things, when Mike joined in the conversation and told us he was looking for a lab technician with a chemistry background to join his team,” said Ladd. She worked with Weintraub for two years, visiting the Arctic twice for sampling as she studied soil nitrogen availability and impacts on plant life.

    Advancing science with cutting-edge instruments

    The work greatly influenced where Ladd would go for her doctoral studies. She was attracted to the Bredesen Center for Interdisciplinary Research & Graduate Education for its close ties to the national lab and the NGEE-Arctic program led by ORNL Environmental Sciences Division Director Stan Wullschleger—as well as by the offer of a personalized Ph.D. program that allows her to pursue science and a parallel track in policy. She began her time with ORNL and UTK in 2013, and is currently pursuing a doctorate in energy science and engineering. She is also an NSF Graduate Research Fellow.

    Wullschleger and UTK adviser Robert Hettich, a scientist in the Mass Spectrometry/Laser Spectroscopy Group at ORNL, helped Ladd design a program around Arctic metabolomics. In this focus area, she studies small molecules in the soil—how they are transported and break down over time, and how soil chemistry changes as temperatures rise.

    “Much of the success with this research is owed to being at ORNL with all the cutting-edge technologies it offers. The mass spectrometry resources here have been integral to getting high-resolution measurements in a short amount of time,” Ladd said.

    Her work for NGEE-Arctic started out in Barrow, Alaska, a coastal plain environment that has interesting microtopography where the soil physically moves as it freezes and thaws, creating rifts and valleys in the landscape. This summer, NGEE-Arctic conducted sampling in Nome, a sub-Arctic region that has undergone more warming and has markedly different, abundant plant life compared with Barrow.

    “My work at ORNL has allowed me to connect my fundamental scientific questions with DOE deliverables,” Mallory said. “It’s a great time to advocate for science, and to make sure we have strong, motivated young scientists doing excellent work.”

    Supporting the next generation of scientists

    Ladd has been very active in supporting her peers. She maintains a blog, “Think Like a Postdoc,” that chronicles her work and dispenses advice to other students.

    She also founded a student group at UTK called Pipeline: Vols for Women in STEM. A part of the university’s Commission for Women, the group works to enhance the status and representation of women in the 50-plus science, technology, engineering, and math fields at UTK through events such as an annual research symposium, interdisciplinary mentoring, monthly lectures, community outreach, and professional and social networking events.

    “The name ‘Pipeline’ refers to the analogy often used to describe the phenomenon that young girls and women are shown to be just as interested and scoring just as high as boys and men in STEM areas in K-12 and as college undergrads. But after graduating we see a divergence in the gender balance where men start to dominate these fields, often referred to as the leaky pipeline,” she said. Research in the past decade has discarded the notion that those changes happen because women start having children or are not “cut out” for long hours, she added.

    “Instead, studies are showing that the culprit is unconscious, or implicit, biases at the systemic level that are discouraging women from pursuing these careers as compared to their white male counterparts. The numbers are even worse for women of color, and especially at the leadership level,” she said. The Pipeline group tracks statistics on gender distribution in STEM areas at the university and aims to reverse that trend.

    Ladd’s curiosity and questioning nature began early. “I always questioned everything, and my parents were a huge part of that. They always encouraged me to not be afraid of standing out and to challenge the status quo. Science has been an outlet for that tendency,” she said. “I like the phrase that science turns ‘I don’t know’ into ‘I don’t know yet.’”

    Ladd grew up playing volleyball, with siblings who played rugby and soccer—meaning a lot of time on the road with various teams. “Our parents always told us it was okay to play in the dirt,” she said. Today away from the lab, she continues to spend time outdoors, kayaking, biking, and rock climbing, adding, “I’m a huge advocate for grad students making time for outside interests.”

    See the full article here .

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    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. 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.

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  • richardmitnick 3:35 pm on December 28, 2017 Permalink | Reply
    Tags: Femtosecond X-ray lasers, Inelastic X-ray scattering, , , ORNL, , , , XFELs   

    From Optics & Photonics: “X-Ray Studies Probe Water’s Elusive Properties” 

    Optics & Photonics

    28 December 2017
    Stewart Wills

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    Unlike most substances, liquid water is denser than its solid phase, ice. [Image: Stockholm University]

    In two different X-ray investigations, researchers have dug into some of the exotic properties of that most familiar of substances—water.

    In one study, researchers from Sweden, Japan and South Korea used a femtosecond X-ray laser to investigate the behavior of evaporatively supercooled liquid water, and to confirm the long-suspected view that water at low temperatures can exist in two different liquid phases (Science). In the other, a U.S.-Japanese team used high-resolution inelastic X-ray scattering to probe the dynamics of water molecules and how the liquid’s hydrogen bonds contribute to its unusual characteristics (Science Advances).

    Burst pipes and floating cubes

    Anyone who has confronted a burst water pipe on a frozen winter morning has firsthand knowledge of one of H20’s unusual characteristics. Whereas most substances increase in density as they go from a liquid to a solid state, water reaches its maximum density at 4°C, above its nominal freezing point of 0°C. That’s also the reason that the ice cubes float at the top of your water glass rather than sinking to the bottom.

    Grappling with this anomalous behavior, a research team at Boston University suggested around 25 years ago, based on computer simulations, that in a metastable, supercooled state, water might actually coexist in two liquid phases—a low-density liquid and a high-density liquid. Those two phases, the researchers proposed, merged into a single phase at a critical point in water phase diagram at around –44°C (analogous to the better-known critical point at a higher temperature between water’s liquid and gas phases).

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    Experiments using femtosecond X-ray free-electron lasers illuminated fluctuations between two different phases of liquid water—a high-density liquid (red) and a low-density liquid (blue)—as a function of temperature in the supercooled regime. [Image: Stockholm University]

    Actually getting liquid water to that frigid point has, however, seemed a bit of a pipe dream. While very pure liquid water can be rapidly supercooled to temperatures moderately below 0°C relatively easily, the proposed critical point lies far below that temperature range, in what researchers have dubbed a “no-man’s land” in which ice crystalizes much faster than the timescale of conventional lab measurements.

    Leveraging ultrafast lasers

    To move past that barrier, a research team led by Anders Nilsson of Stockholm University, Sweden, turned to the rapid timescales enabled by femtosecond X-ray free-electron lasers (XFELs). At XFEL facilities in Korea and Japan [un-named], the team sent a stream of tiny water droplets (approximately 14 microns in diameter) into a vacuum chamber, and fired the XFEL at the droplets at varying distances from the water-dispensing nozzle to obtain ultrafast X-ray scattering data.

    The tiny size of the droplets meant that as they traveled through the vacuum they rapidly evaporatively cooled—with the amount of cooling related to the time they spent in vacuum under a well-established formula. Thus, by taking X-ray measurements at varying distances from the nozzle, the researchers could examine the structural behavior of the liquid water at multiple temperatures in the deep-supercooling regime, near the hypothesized critical point. “We were able to X-ray unimaginably fast before the ice froze,” Nilsson said in a press release, “and could observe how it fluctuated” between the two hypothesized metastable phases of liquid water.

    The experiments allowed the team to flesh out the phase diagram of liquid water in a supercooled region previously thought to be inaccessible to experiment. And the researchers believe that the use of femtosecond XFELs to probe thermodynamic functions and structural changes at extreme states “can be generalized to many supercooled liquids.”

    Illuminating water’s dynamics

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    A team led by scientists at the U.S. Oak Ridge National Laboratory used inelastic X-ray scattering to visualize and quantify the movement of water molecules in space and time. [Image: Jason Richards/Oak Ridge National Laboratory, US Dept. of Energy]

    A second set of experiments, from researchers at the U.S. Oak Ridge National Laboratory, the University of Tennessee, and the SPring-8 synchrotron laboratory in Japan, looked at water’s dynamics at room temperature, using inelastic X-ray scattering (IXS).

    SPring-8 synchrotron, located in Hyōgo Prefecture, Japan

    The researchers illuminated these dynamics through a series of experiments in which they trained radiation from the SPring-8 facility’s high-resolution IXS beamline, BL35XU, onto a 2-mm-thick sample of liquid water. Through multiple scattering measurements across a range of momentum and energy-transfer values, the team was able to build a detailed picture of the so-called Van Hove function, which describes the probability of interactions between a molecule and its nearest neighbors as a function of distance and time.

    The team found that water’s hydrogen bonds behave in a highly correlated fashion with respect to one another, which gives liquid water its high stability and explains its viscosity characteristics. And, in a press release, the researchers further speculated that the techniques used here could be extended to studying the dynamics and viscosity of a variety of other liquids. Some of those studies, they suggested, could prove useful in “the development of new types of semiconductor devices with liquid electrolyte insulating layers, better batteries and improved lubricants.”

    Here, the research team was interested in sussing out how water molecules interact in real time, and how the strongly directional hydrogen bonds of water molecules work together to determine properties such the liquid’s viscosity.

    See the full article here .

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    Optics & Photonics News (OPN) is The Optical Society’s monthly news magazine. It provides in-depth coverage of recent developments in the field of optics and offers busy professionals the tools they need to succeed in the optics industry, as well as informative pieces on a variety of topics such as science and society, education, technology and business. OPN strives to make the various facets of this diverse field accessible to researchers, engineers, businesspeople and students. Contributors include scientists and journalists who specialize in the field of optics. We welcome your submissions.

     
  • richardmitnick 4:48 pm on November 28, 2017 Permalink | Reply
    Tags: Cleaning automotive exhaust, , ORNL, SSZ-13 and ZSM-5 catalysts, Zeolite (hydrous silicate) catalytic converters   

    From ORNL: “Researchers compare ‘new’ and ‘aged’ catalytic converter at the nanoscale level” 

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    Oak Ridge National Laboratory

    November 28, 2017
    Dawn Levy, Communications
    levyd@ornl.gov
    865.576.6448

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    Scientists peer inside materials used to clean automotive exhaust to understand why one works better than the other. Red and blue dots represent positions of copper and aluminum atoms, respectively, for two zeolite catalysts (SSZ-13 and ZSM-5) used in a diesel catalytic converter for a new car (fresh catalyst) and a car that has driven 135,000 miles (aged catalyst). After long use, SSZ-13 cleans exhaust better than ZSM-5. These atom-by-atom images reveal that this result is due to greater aggregation of copper and aluminum in ZSM-5. Image credit: Oak Ridge National Laboratory, U.S. Dept. of Energy

    Diesel vehicles today emit far fewer pollutants than older vehicles, thanks to a zeolite (hydrous silicate) catalytic converter that was invented around 10 years ago to reduce pollutants that cause the formation of acid rain and smog. Although many groups have investigated this catalyst, it remains unclear why a specific zeolite catalyst is much more effective than previous catalysts.

    By managing to “see inside” the zeolite particles in three dimensions at the nanoscale, researchers from Utrecht University in the Netherlands and the Department of Energy’s Oak Ridge National Laboratory have been able to directly image phenomena responsible for their enhanced stability and durability.

    After simulating 135,000 miles of engine use, they compared a ‘new’ and an ‘aged’ version of the zeolite catalyst, which revealed that this catalyst retains much more of its original structure than other diesel catalyst formulations. The researchers also found the underlying reasons this zeolite catalyst is so much more stable over its lifespan and experiences only minimal damage. The results are published in Nature Communications.

    Diesel catalytic converters are exposed to frequent temperature changes, extremely hot steam and pollutants, but they must remain stable for the entire life of the vehicle. The observed stability of this particular catalyst is due in part to its complexity.

    “At first glance, zeolites may seem easy to understand, but the more you study them, the more fascinated you become by their complexity,” said Joel Schmidt of Utrecht University, lead author of the publication. “In this material, it is becoming more and more evident that the way its structure isolates the active reaction site is key to its stability, and advanced characterization methods that can help us understand the active catalyst site environment are vital to knowing the subtle, but important details of materials utilized in zeolite catalytic converters.”

    Schmidt and his colleagues from Utrecht University connected with Jonathan Poplawsky at the Center for Nanophase Materials Sciences (CNMS), a DOE Office of Science User Facility at ORNL, to analyze the three-dimensional elemental distribution within the zeolite catalyst using a unique and powerful tool called local electrode atom probe tomography. With this technique, they could visualize all of the catalysts’ relevant chemical elements with three-dimensional resolution close to the atomic scale, for the as-produced “new” catalyst and after a 135,000-mile simulated aging procedure.

    The researchers found that after aging, the zeolite catalyst exhibits enhanced stability compared with other diesel-vehicle catalysts due primarily to structural and chemical properties that prevent the formation of a deactivating copper-aluminum-oxide phase. Thus, the optimal nanoscale distribution of elements within the zeolite structure—which enables optimal cleaning of combustion byproducts—remains intact during aging.

    “With this unique approach, we were able to add another piece to the puzzle of how to design catalysts that perform just as well at the end of a vehicle’s life as they did the day they rolled out of the factory,” said Bert Weckhuysen, Utrecht professor and co-author of the publication. “Since zeolite catalysts are used broadly in the chemical industry as well, insight on the migration of chemical elements under catalytic operating conditions is a very relevant contribution to realize more sustainable processes.”

    This work is supported by the NWO Gravitation program, Netherlands Center for Multiscale Catalytic Energy Conversion, and the European Research Council. The atom probe tomography measurements were conducted at CNMS.

    See the full article here .

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  • richardmitnick 8:24 pm on October 13, 2017 Permalink | Reply
    Tags: A new ultrafast optical technique for thermal measurements—time-domain thermoreflectance, , Chengyun Hua, , ORNL, ,   

    From ORNL: Women in STEM – “Laser-Focused: Chengyun Hua turns the heat up on materials research” 

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    Oak Ridge National Laboratory

    October 13, 2017
    Bill Cabage
    cabagewh@ornl.gov
    865.574.4399

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    Chengyun Hua applied for a Liane B. Russell Distinguished Early Career Fellowship after meeting ORNL researchers at a Society of Women Engineers conference.

    In Chengyun Hua’s research, everything revolves around heat and how it moves. As a Russell Fellow at the Department of Energy’s Oak Ridge National Laboratory, Hua carefully analyzes nanoscale heat transfer mechanisms using laser spectroscopy.

    “Heat is being generated from everywhere and we can collect that heat and convert it to energy,” she explained. “We essentially have enough heat being produced 24/7 through electronics and other sources that we could potentially impact the world’s energy production and ease today’s energy concerns.”

    Although heat has the potential to generate enough energy to power the universe, if not channeled properly, it can also become problematic.

    “We’ve seen recent news of cell phones bursting into flames,” Hua said. “The reason is too much heat is produced locally, and it has nowhere to go in a short period of time. The challenge is to capture that heat flow at the nanoscale and understand how we can more effectively dissipate it.”

    Through Hua’s work in ORNL’s Building Equipment Research group, a new ultrafast optical technique for thermal measurements—time-domain thermoreflectance—was deployed at ORNL for the first time. The technique measures the thermal properties of materials, including thermal conductivity. Using ORNL’s Ultrafast Laser Spectroscopy Laboratory, Hua measures material conductivity down to the nanometer.

    “When a material is heated using a pulsed laser, thermal stress is induced,” she explained. “The objective of raising the temperature of a material is to unveil the microscopic processes of the phonons [a type of elementary particle that plays an important role in many of the physical properties of solids, such as the thermal conductivity and the electrical conductivity] that govern the heat transport in solids. Ultimately, with this better understanding, we can design the next generation of materials—materials that not only withstand heat but also manage the heat and convert it into energy.”

    For the love of physics

    Hua grew up a world away in Shanghai, China. An only child of accountant parents, she excelled in mathematics and science, something that was not unusual in her home country.

    “It’s easy to get a job in the engineering discipline in China; it’s a highly respected profession,” she said. For Hua, however, getting accepted to study engineering physics at the University of Michigan, Ann Arbor, was an opportunity not to be missed.

    “Studying in Michigan was the first time I had ever been to the United States,” she said. “But it wasn’t until I entered the mechanical engineering program at Cal Tech that I truly felt at home.”

    Hua completed her PhD in mechanical engineering at the California Institute of Technology at Pasadena. There she met an advisor and professor who helped steer her current career path, challenging her to continue focusing on nanoscale heat transfer properties. “Cal Tech was a unique playground if you love mathematics and physics,” she said.

    After meeting some ORNL researchers at a Society of Women Engineers conference, Hua made the decision in early 2016 to apply for a fellowship that would allow her to focus on micro- and nanoscale heat transfer and energy conversion at the lab. The Liane B. Russell Distinguished Early Career Fellowship attracts scientists who have demonstrated outstanding scientific ability and research interests that align with core capabilities at the lab.

    “My advisor encouraged me to apply and within one week I wrote my proposal on ‘Exploring Thermal Transport in Nanostructured Materials for Thermal Energy Conversion and Management.’ I interviewed in November 2015 and four days after the new year, I was invited to become a fellow at ORNL,” she said.

    Uprooting again to East Tennessee, Hua has found a supportive community that encourages the sharing of new ideas and interdisciplinary research.

    “I’ve been able to live in different parts of the U.S.,” she said. “But, everywhere I’ve been, I’ve found support and an environment that promotes ideas and stimulating conversation between scientists.”

    While Hua has adapted to many moves and changes, one part of her research and studies remains unchanged.

    “Heat always flows from hot to cold,” she said. “It’s the constant in the continuum.”

    See the full article here .

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  • richardmitnick 9:32 am on July 7, 2017 Permalink | Reply
    Tags: , , , ORNL, St. Jude Children’s Research Hospital   

    From ORNL: “ORNL researchers apply imaging, computational expertise to St. Jude research” 

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    Oak Ridge National Laboratory

    July 6, 2017
    Stephanie G. Seay
    seaysg@ornl.gov
    865.576.9894

    1
    Left to right: ORNL’s Derek Rose, Matthew Eicholtz, Philip Bingham, Ryan Kerekes, and Shaun Gleason.

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    Measuring migrating neurons in a developing mouse brain.

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    Identifying and analyzing neurons in a mouse auditory cortex.
    No image credits for above images

    In the quest to better understand and cure childhood diseases, scientists at St. Jude Children’s Research Hospital accumulate enormous amounts of data from powerful video microscopes. To help St. Jude scientists mine that trove of data, researchers at Oak Ridge National Laboratory have created custom algorithms that can provide a deeper understanding of the images and quicken the pace of research.

    The work resides in St. Jude’s Department of Developmental Neurobiology in Memphis, Tennessee, where scientists use advanced microscopy to capture the details of phenomena such as nerve cell growth and migration in the brains of mice. ORNL researchers take those videos and leverage their expertise in image processing, computational science, and machine learning to analyze the footage and create statistics.

    A recent Science article details St. Jude research on brain plasticity, or the ability of the brain to change and form new connections between neurons. In this work, ORNL helped track mice brain cell electrical activity in the auditory cortex when the animals were exposed to certain tones.

    ORNL researchers created an algorithm to measure electrical activations, or signals, across groups of neurons, collecting statistics and making correlations between cell activity in the auditory cortex and tones heard by the mice. The team first had to stabilize the video because it was taken while the mice were awake and moving to ensure a proper analysis was being conducted, said Derek Rose, who now leads the work at ORNL.

    See the full article here .

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    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. 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.

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  • richardmitnick 3:37 pm on July 5, 2017 Permalink | Reply
    Tags: A condensed matter cousin of the Higgs boson, Condensed matter researchers have recently uncovered new quantum states known as quasiparticles including the Higgs mode, Higgs amplitude mode, Neutron scattering techniques, ORNL   

    From ORNL: “Neutrons detect elusive Higgs amplitude mode in quantum material” 

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    Oak Ridge National Laboratory

    July 5, 2017
    Sara Shoemaker
    shoemakerms@ornl.gov
    865.576.9219

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    ORNL’s Tao Hong analyzed a copper bromide compound’s low-energy behavior during a neutron scattering experiment at the lab’s High Flux Isotope Reactor that yielded the elusive Higgs amplitude mode in two dimensions with no decay.

    ORNL High Flux Isotope Reactor

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    The ORNL-led research team selected a crystal composed of copper bromide – because the copper ion is ideal for studying exotic quantum effects – to observe the elusive Higgs amplitude mode in two dimensions. The sample was examined using cold neutron triple-axis spectrometer beams for neutron scattering at the High Flux Isotope Reactor.

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    During the neutron scattering experiment, the sample containing copper ions exhibited exotic quantum properties as certain quasiparticles spin in a wave-like configuration, eventually revealing the Higgs amplitude mode.

    A team led by the Department of Energy’s Oak Ridge National Laboratory has used sophisticated neutron scattering techniques to detect an elusive quantum state known as the Higgs amplitude mode in a two-dimensional material.

    The Higgs amplitude mode is a condensed matter cousin of the Higgs boson, the storied quantum particle theorized in the 1960s and proven experimentally in 2012. It is one of a number of quirky, collective modes of matter found in materials at the quantum level. By studying these modes, condensed matter researchers have recently uncovered new quantum states known as quasiparticles, including the Higgs mode.

    These studies provide unique opportunities to explore quantum physics and apply its exotic effects in advanced technologies such as spin-based electronics, or spintronics, and quantum computing.

    “To excite a material’s quantum quasiparticles in a way that allows us to observe the Higgs amplitude mode is quite challenging,” said Tao Hong, an instrument scientist with ORNL’s Quantum Condensed Matter Division.

    Although the Higgs amplitude mode has been observed in various systems, “the Higgs mode would often become unstable and decay, shortening the opportunity to characterize it before losing sight of it,” Hong said.

    The ORNL-led team offered an alternative method. The researchers selected a crystal composed of copper bromide, because the copper ion is ideal for studying exotic quantum effects, Hong explained. They began the delicate task of “freezing” the material’s agitating quantum-level particles by lowering its temperature to 1.4 Kelvin, which is about minus 457.15 degrees Fahrenheit.

    The researchers fine-tuned the experiment until the particles reached the phase located near the desired quantum critical point—the sweet spot where collective quantum effects spread across wide distances in the material, which creates the best conditions to observe a Higgs amplitude mode without decay.

    With neutron scattering performed at ORNL’s High Flux Isotope Reactor, the research team observed the Higgs mode with an infinite lifetime: no decay.

    “There’s an ongoing debate in physics about the stability of these very delicate Higgs modes,” said Alan Tennant, chief scientist of ORNL’s Neutron Sciences Directorate. “This experiment is really hard to do, especially in a two-dimensional system. And, yet, here’s a clear observation, and it’s stabilized.”

    The research team’s observation provides new insights into the fundamental theories underlying exotic materials including superconductors, charge-density wave systems, ultracold bosonic systems and antiferromagnets.

    “These breakthroughs are having widespread impact on our understanding of materials’ behavior at the atomic scale,” Hong added.

    The study, titled, Direct observation of the Higgs amplitude mode in a two-dimensional quantum antiferromagnet near the quantum critical point, was published in Nature Physics. It was co-authored by ORNL’s Tao Hong, Sachith E. Dissanayake, Harish Agrawal and David A. (Alan) Tennant, and scientists from Shizuoka University, the National Institute of Standards and Technology [NIST], University of Maryland, University of Jordan, Clark University, Helmholtz-Zentrum Berlin for Materials and Energy and Lehrstuhl für Theoretische Physik I.

    The team used cold neutron triple-axis spectrometer beams for studying exotic magnetic effects and analyzed low-energy excitations in the copper bromide compound. The unpolarized neutron scattering measurements were performed at ORNL’s HFIR and at Helmholtz-Zentrum Berlin for Materials and Energy. For contrasting data from polarized neutron-scattering measurements, they also employed a high-intensity multi-axis crystal spectrometer at NIST’s Center for Neutron Research.

    The work performed at ORNL’s HFIR, a DOE Office of Science User Facility, and was funded by the DOE Office of Science.

    See the full article here .

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  • richardmitnick 3:19 pm on June 28, 2017 Permalink | Reply
    Tags: , IMAGINE neutron scattering diffractometer, LPMOs - lytic polysaccharide monooxygenases, , North Carolina State University, ORNL, ORNL’s High Flux Isotope Reactor   

    From ORNL: “‘On your mark, get set'” 

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    Oak Ridge National Laboratory

    June 27, 2017
    Jeremy Rumsey
    rumseyjp@ornl.gov
    865.576.2038

    1
    A combination of X-ray and neutron scattering has revealed new insights into how a highly efficient industrial enzyme is used to break down cellulose. Knowing how oxygen molecules (red) bind to catalytic elements (illustrated by a single copper ion) will guide researchers in developing more efficient, cost-effective biofuel production methods. (Image credit: ORNL/Jill Hemman)

    Producing biofuels like ethanol from plant materials requires various enzymes to break down the cellulosic fibers. Scientists using neutron scattering have identified the specifics of an enzyme-catalyzed reaction that could significantly reduce the total amount of enzymes used, improving production processes and lowering costs.

    Researchers from the Department of Energy’s Oak Ridge National Laboratory and North Carolina State University used a combination of X-ray and neutron crystallography to determine the detailed atomic structure of a specialized fungal enzyme.

    A deeper understanding of the enzyme reactivity could also lead to improved computational models that will further guide industrial applications for cleaner forms of energy. Their results are published in the journal Angewandte Chemie International Edition.

    Part of a larger family known as lytic polysaccharide monooxygenases, or LPMOs, these oxygen-dependent enzymes act in tandem with hydrolytic enzymes—which chemically break down large complex molecules with water—by oxidizing and breaking the bonds that hold cellulose chains together. The combined enzymes can digest biomass more quickly than currently used enzymes and speed up the biofuel production process.

    “These enzymes are already used in industrial applications, but they’re not well understood,” said lead author Brad O’Dell, a graduate student from NC State working in the Biology and Soft Matter Division of ORNL’s Neutron Sciences Directorate. “Understanding each step in the LPMO mechanism of action will help industry use these enzymes to their full potential and, as a result, make final products cheaper.”

    In an LPMO enzyme, oxygen and cellulose arrange themselves through a sequence of steps before the biomass deconstruction reaction occurs. Sort of like “on your mark, get set, go,” says O’Dell.

    To better understand the enzyme’s reaction mechanism, O’Dell and coauthor Flora Meilleur, ORNL instrument scientist and an associate professor at NC State, used the IMAGINE neutron scattering diffractometer at ORNL’s High Flux Isotope Reactor to see how the enzyme and oxygen molecules were behaving in the steps leading up to the reaction—from the “resting state” to the “active state.”

    ORNL IMAGINE neutron scattering diffractometer

    The resting state, O’Dell says, is where all the critical components of the enzyme assemble to bind oxygen and carbohydrate. When electrons are delivered to the enzyme, the system moves from the resting state to the active state—i.e., from “on your mark” to “get set.”

    In the active state, oxygen binds to a copper ion that initiates the reaction. Aided by X-ray and neutron diffraction, O’Dell and Meilleur identified a previously unseen oxygen molecule being stabilized by an amino acid, histidine 157.

    Hydrogen is a key element of amino acids like histidine 157. Because neutrons are particularly sensitive to hydrogen atoms, the team was able to determine that histidine 157 plays a significant role in transporting oxygen molecules to the copper ion in the active site, revealing a vital detail about the first step of the LPMO catalytic reaction.

    “Because neutrons allow us to see hydrogen atoms inside the enzyme, we gained essential information in deciphering the protein chemistry. Without that data, the role of histidine 157 would have remained unclear,” Meilleur said. “Neutrons were instrumental in determining how histidine 157 stabilizes oxygen to initiate the first step of the LPMO reaction mechanism.”

    Their results were subsequently confirmed via quantum chemical calculations performed by coauthor Pratul Agarwal from ORNL’s Computing and Computational Sciences Directorate.

    Research material preparation was supported by the ORNL Center for Structural Molecular Biology. X-ray data were collected at the Argonne National Laboratory Advanced Photon Source through access provided by the Southeast Regional Collaborative Access Team.

    O’Dell says their results refine the current understanding of LPMOs for science and industry researchers.

    “This is a big step forward in unraveling how LPMO’s initiate the breakdown of carbohydrates,” O’Dell said. “Now we need to characterize the enzyme’s activated state when the protein is also bound to a carbohydrate that mimics cellulose. Then we’ll have the chance to see what structural changes happen when the starting pistol is fired and the reaction takes off.”

    HFIR is a DOE Office of Science User Facility. UT-Battelle manages ORNL for the Office of Science. 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 http://science.energy.gov/.

    See the full article here .

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    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. 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.

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  • richardmitnick 3:19 pm on May 9, 2017 Permalink | Reply
    Tags: $3.9 Million to Help Industry Address High Performance Computing Challenges, , ORNL   

    From ORNL via energy.gov: “Energy Department Announces $3.9 Million to Help Industry Address High Performance Computing Challenges” 

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    Oak Ridge National Laboratory

    ENERGY.GOV

    May 8, 2017
    Today, the U.S. Department of Energy announced nearly $3.9 million for 13 projects designed to stimulate the use of high performance supercomputing in U.S. manufacturing. The Office of Energy Efficiency and Renewable Energy (EERE) Advanced Manufacturing Office’s High Performance Computing for Manufacturing (HPC4Mfg) program enables innovation in U.S. manufacturing through the adoption of high performance computing (HPC) to advance applied science and technology relevant to manufacturing. HPC4Mfg aims to increase the energy efficiency of manufacturing processes, advance energy technology, and reduce energy’s impact on the environment through innovation.

    The 13 new project partnerships include application of world-class computing resources and expertise of the national laboratories including Lawrence Livermore National Laboratory, Oak Ridge National Laboratory, Lawrence Berkley National Laboratory, National Renewable Energy Laboratory, and Argonne National Laboratory. These projects will address key challenges in U.S. manufacturing proposed in partnership with companies and improve energy efficiency across the manufacturing industry through applied research and development of energy technologies.

    Each of the 13 newly selected projects will receive up to $300,000 to support work performed by the national lab partners and allow the partners to use HPC compute cycles.

    The 13 projects selected for awards are led by:

    7AC Technologies
    8 Rivers Capital
    Applied Materials, Inc.
    Arconic Inc.*
    Ford Motor Company
    General Electric Global Research Center*
    LanzaTech
    Samsung Semiconductor, Inc.
    Sierra Energy
    The Timken Company
    United Technologies Research Corporation

    *Awarded two projects

    Read more about the individual projects.

    The Advanced Manufacturing Office (AMO) recently published a draft of its Multi-year Program Plan that identifies the technology, research and development, outreach, and crosscutting activities that AMO plans to focus on over the next five years. Some of the technical focus areas in the plan align with the high-priority, energy-related manufacturing activities that the HPC4Mfg program also aims to address.

    Led by Lawrence Livermore National Laboratory, with Lawrence Berkeley National Laboratory and Oak Ridge National Laboratory as strong partners, the HPC4Mfg program has a diverse portfolio of small and large companies, consortiums, and institutes within varying industry sectors that span the country. Established in 2015, it currently supports 28 projects that range from improved turbine blades for aircraft engines and reduced heat loss in electronics, to steel-mill energy efficiency and improved fiberglass production.

    ORNL Cray XK7 Titan Supercomputer

    See the full article here .

    Please help promote STEM in your local schools.

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    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. 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.

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  • richardmitnick 10:08 am on April 26, 2017 Permalink | Reply
    Tags: , , Building the Bridge to Exascale, , , , ORNL,   

    From OLCF at ORNL: “Building the Bridge to Exascale” 

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    Oak Ridge National Laboratory

    OLCF

    April 18, 2017 [Where was this hiding?]
    Katie Elyce Jones

    Building an exascale computer—a machine that could solve complex science problems at least 50 times faster than today’s leading supercomputers—is a national effort.

    To oversee the rapid research and development (R&D) of an exascale system by 2023, the US Department of Energy (DOE) created the Exascale Computing Project (ECP) last year. The project brings together experts in high-performance computing from six DOE laboratories with the nation’s most powerful supercomputers—including Oak Ridge, Argonne, Lawrence Berkeley, Lawrence Livermore, Los Alamos, and Sandia—and project members work closely with computing facility staff from the member laboratories.

    ORNL IBM Summit supercomputer depiction.

    At the Exascale Computing Project’s (ECP’s) annual meeting in February 2017, Oak Ridge Leadership Computing Facility (OLCF) staff discussed OLCF resources that could be leveraged for ECP research and development, including the facility’s next flagship supercomputer, Summit, expected to go online in 2018.

    At the first ECP annual meeting, held January 29–February 3 in Knoxville, Tennessee, about 450 project members convened to discuss collaboration in breakout sessions focused on project organization and upcoming R&D milestones for applications, software, hardware, and exascale systems focus areas. During facility-focused sessions, senior staff from the Oak Ridge Leadership Computing Facility (OLCF) met with ECP members to discuss opportunities for the project to use current petascale supercomputers, test beds, prototypes, and other facility resources for exascale R&D. The OLCF is a DOE Office of Science User Facility located at DOE’s Oak Ridge National Laboratory (ORNL).

    “The ECP’s fundamental responsibilities are to provide R&D to build exascale machines more efficiently and to prepare the applications and software that will run on them,” said OLCF Deputy Project Director Justin Whitt. “The facilities’ responsibilities are to acquire, deploy, and operate the machines. We are currently putting advanced test beds and prototypes in place to evaluate technologies and enable R&D efforts like those in the ECP.”

    ORNL has a unique connection to the ECP. The Tennessee-based laboratory is the location of the project office that manages collaboration within the ECP and among its facility partners. ORNL’s Laboratory Director Thom Mason delivered the opening talk at the conference, highlighting the need for coordination in a project of this scope.

    On behalf of facility staff, Mark Fahey, director of operations at the Argonne Leadership Computing Facility, presented the latest delivery and deployment plans for upcoming computing resources during a plenary session. From the OLCF, Project Director Buddy Bland and Director of Science Jack Wells provided a timeline for the availability of Summit, OLCF’s next petascale supercomputer, which is expected to go online in 2018; it will be at least 5 times more powerful than the OLCF’s 27-petaflop Titan supercomputer.

    ORNL Cray XK7 Titan Supercomputer.

    “Exascale hardware won’t be around for several more years,” Wells said. “The ECP will need access to Titan, Summit, and other leadership computers to do the work that gets us to exascale.”

    Wells said he was able to highlight the spring 2017 call for Innovative and Novel Computational Impact on Theory and Experiment, or INCITE, proposals, which will give 2-year projects the first opportunity for computing time on Summit. OLCF staff also introduced a handful of computing architecture test beds—including the developmental environment for Summit known as Summitdev, NVIDIA’s deep learning and accelerated analytics system DGX-1, an experimental cluster of ARM 64-bit compute nodes, and a Cray XC40 cluster of 168 nodes known as Percival—that are now available for OLCF users.

    In addition to leveraging facility resources for R&D, the ECP must understand the future needs of facilities to design an exascale system that is ready for rigorous computational science simulations. Facilities staff can offer insight about the level of performance researchers will expect from science applications on exascale systems and estimate the amount of space and electrical power that will be available in the 2023 timeframe.

    “Getting to capable exascale systems will require careful coordination between the ECP and the user facilities,” Whitt said.

    One important collaboration so far was the development of a request for information, or RFI, for exascale R&D that the ECP released in February to industry vendors. The RFI enables the ECP to evaluate potential software and hardware technologies for exascale systems—a step in the R&D process that facilities often undertake. Facilities will later release requests for proposals when they are ready to begin building exascale systems

    See the full article here .

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    The Oak Ridge Leadership Computing Facility (OLCF) was established at Oak Ridge National Laboratory in 2004 with the mission of accelerating scientific discovery and engineering progress by providing outstanding computing and data management resources to high-priority research and development projects.

    ORNL’s supercomputing program has grown from humble beginnings to deliver some of the most powerful systems in the world. On the way, it has helped researchers deliver practical breakthroughs and new scientific knowledge in climate, materials, nuclear science, and a wide range of other disciplines.

    The OLCF delivered on that original promise in 2008, when its Cray XT “Jaguar” system ran the first scientific applications to exceed 1,000 trillion calculations a second (1 petaflop). Since then, the OLCF has continued to expand the limits of computing power, unveiling Titan in 2013, which is capable of 27 petaflops.


    ORNL Cray XK7 Titan Supercomputer

    Titan is one of the first hybrid architecture systems—a combination of graphics processing units (GPUs), and the more conventional central processing units (CPUs) that have served as number crunchers in computers for decades. The parallel structure of GPUs makes them uniquely suited to process an enormous number of simple computations quickly, while CPUs are capable of tackling more sophisticated computational algorithms. The complimentary combination of CPUs and GPUs allow Titan to reach its peak performance.

    The OLCF gives the world’s most advanced computational researchers an opportunity to tackle problems that would be unthinkable on other systems. The facility welcomes investigators from universities, government agencies, and industry who are prepared to perform breakthrough research in climate, materials, alternative energy sources and energy storage, chemistry, nuclear physics, astrophysics, quantum mechanics, and the gamut of scientific inquiry. Because it is a unique resource, the OLCF focuses on the most ambitious research projects—projects that provide important new knowledge or enable important new technologies.

     
  • richardmitnick 10:31 am on March 29, 2017 Permalink | Reply
    Tags: A Seismic Mapping Milestone, , , , ORNL, ,   

    From ORNL: “A Seismic Mapping Milestone” 

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    Oak Ridge National Laboratory

    March 28, 2017

    Jonathan Hines
    hinesjd@ornl.gov
    865.574.6944

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    This visualization is the first global tomographic model constructed based on adjoint tomography, an iterative full-waveform inversion technique. The model is a result of data from 253 earthquakes and 15 conjugate gradient iterations with transverse isotropy confined to the upper mantle. Credit: David Pugmire, ORNL

    When an earthquake strikes, the release of energy creates seismic waves that often wreak havoc for life at the surface. Those same waves, however, present an opportunity for scientists to peer into the subsurface by measuring vibrations passing through the Earth.

    Using advanced modeling and simulation, seismic data generated by earthquakes, and one of the world’s fastest supercomputers, a team led by Jeroen Tromp of Princeton University is creating a detailed 3-D picture of Earth’s interior. Currently, the team is focused on imaging the entire globe from the surface to the core–mantle boundary, a depth of 1,800 miles.

    These high-fidelity simulations add context to ongoing debates related to Earth’s geologic history and dynamics, bringing prominent features like tectonic plates, magma plumes, and hotspots into view. In September 2016, the team published a paper in Geophysical Journal International on its first-generation global model. Created using data from 253 earthquakes captured by seismograms scattered around the world, the team’s model is notable for its global scope and high scalability.

    “This is the first global seismic model where no approximations—other than the chosen numerical method—were used to simulate how seismic waves travel through the Earth and how they sense heterogeneities,” said Ebru Bozdag, a coprincipal investigator of the project and an assistant professor of geophysics at the University of Nice Sophia Antipolis. “That’s a milestone for the seismology community. For the first time, we showed people the value and feasibility of running these kinds of tools for global seismic imaging.”

    The project’s genesis can be traced to a seismic imaging theory first proposed in the 1980s. To fill in gaps within seismic data maps, the theory posited a method called adjoint tomography, an iterative full-waveform inversion technique. This technique leverages more information than competing methods, using forward waves that travel from the quake’s origin to the seismic receiver and adjoint waves, which are mathematically derived waves that travel from the receiver to the quake.

    The problem with testing this theory? “You need really big computers to do this,” Bozdag said, “because both forward and adjoint wave simulations are performed in 3-D numerically.”

    In 2012, just such a machine arrived in the form of the Titan supercomputer, a 27-petaflop Cray XK7 managed by the US Department of Energy’s (DOE’s) Oak Ridge Leadership Computing Facility (OLCF), a DOE Office of Science User Facility located at Oak Ridge National Laboratory.


    ORNL Cray XK7 Titan Supercomputer

    After trying out its method on smaller machines, Tromp’s team gained access to Titan in 2013. Working with OLCF staff, the team continues to push the limits of computational seismology to deeper depths.

    Stitching Together Seismic Slices

    As quake-induced seismic waves travel, seismograms can detect variations in their speed. These changes provide clues about the composition, density, and temperature of the medium the wave is passing through. For example, waves move slower when passing through hot magma, such as mantle plumes and hotspots, than they do when passing through colder subduction zones, locations where one tectonic plate slides beneath another.

    Each seismogram represents a narrow slice of the planet’s interior. By stitching many seismograms together, researchers can produce a 3-D global image, capturing everything from magma plumes feeding the Ring of Fire, to Yellowstone’s hotspots, to subducted plates under New Zealand.

    This process, called seismic tomography, works in a manner similar to imaging techniques employed in medicine, where 2-D x-ray images taken from many perspectives are combined to create 3-D images of areas inside the body.

    In the past, seismic tomography techniques have been limited in the amount of seismic data they can use. Traditional methods forced researchers to make approximations in their wave simulations and restrict observational data to major seismic phases only. Adjoint tomography based on 3-D numerical simulations employed by Tromp’s team isn’t constrained in this way. “We can use the entire data—anything and everything,” Bozdag said.

    Digging Deeper

    To improve its global model further, Tromp’s team is experimenting with model parameters on Titan. For example, the team’s second-generation model will introduce anisotropic inversions, which are calculations that better capture the differing orientations and movement of rock in the mantle. This new information should give scientists a clearer picture of mantle flow, composition, and crust–mantle interactions.

    Additionally, team members Dimitri Komatitsch of Aix-Marseille University in France and Daniel Peter of King Abdullah University in Saudi Arabia are leading efforts to simulate higher-frequency seismic waves. This would allow the team to model finer details in the Earth’s mantle and even begin mapping the Earth’s core.

    To make this leap, Tromp’s team is preparing for Summit, the OLCF’s next-generation supercomputer.


    ORNL IBM Summit supercomputer depiction

    Set to arrive in 2018, Summit will provide at least five times the computing power of Titan. As part of the OLCF’s Center for Accelerated Application Readiness, Tromp’s team is working with OLCF staff to take advantage of Summit’s computing power upon arrival.

    “With Summit, we will be able to image the entire globe from crust all the way down to Earth’s center, including the core,” Bozdag said. “Our methods are expensive—we need a supercomputer to carry them out—but our results show that these expenses are justified, even necessary.”

    See the full article here .

    Please help promote STEM in your local schools.

    STEM Icon

    Stem Education Coalition

    ORNL is managed by UT-Battelle for the Department of Energy’s Office of Science. 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.

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