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How a Single Chemical Bond Balances Cells Between Life and Death

With SLAC's X-ray laser and synchrotron, scientists measured exactly how much energy goes into keeping a crucial chemical bond from triggering a cell's death spiral.

New Efficient, Low-Temperature Catalyst for Converting Water and CO to Hydrogen Gas and CO2

Scientists have developed a new low-temperature catalyst for producing high-purity hydrogen gas while simultaneously using up carbon monoxide (CO). The discovery could improve the performance of fuel cells that run on hydrogen fuel but can be poisoned by CO.

Study Sheds Light on How Bacterial Organelles Assemble

Scientists at Berkeley Lab and Michigan State University are providing the clearest view yet of an intact bacterial microcompartment, revealing at atomic-level resolution the structure and assembly of the organelle's protein shell. This work can help provide important information for research in bioenergy, pathogenesis, and biotechnology.

A Single Electron's Tiny Leap Sets Off 'Molecular Sunscreen' Response

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

Researchers Find New Mechanism for Genome Regulation

The same mechanisms that separate mixtures of oil and water may also help the organization of an unusual part of our DNA called heterochromatin, according to a new study by Berkeley Lab researchers. They found that liquid-liquid phase separation helps heterochromatin organize large parts of the genome into specific regions of the nucleus. The work addresses a long-standing question about how DNA functions are organized in space and time, including how genes are silenced or expressed.

The Rise of Giant Viruses

Research reveals that giant viruses acquire genes piecemeal from others, with implications for bioenergy production and environmental cleanup.

Grasses: The Secrets Behind Their Success

Researchers find a grass gene affecting how plants manage water and carbon dioxide that could be useful to growing biofuel crops on marginal land.

SLAC Experiment is First to Decipher Atomic Structure of an Intact Virus with an X-ray Laser

An international team of scientists has for the first time used an X-ray free-electron laser to unravel the structure of an intact virus particle on the atomic level. The method dramatically reduces the amount of virus material required, while also allowing the investigations to be carried out several times faster than before. This opens up entirely new research opportunities.

New Perspectives Into Arctic Cloud Phases

Teamwork provides insight into complicated cloud processes that are important to potential environmental changes in the Arctic.

Illuminating a Better Way to Calculate Excitation Energy

In a new study appearing this week in The Journal of Chemical Physics, researchers demonstrate a new method to calculate excitation energies. They used a new approach based on density functional methods, which use an atom-by-atom approach to calculate electronic interactions. By analyzing a benchmark set of small molecules and oligomers, their functional produced more accurate estimates of excitation energy compared to other commonly used density functionals, while requiring less computing power.


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Chicago Quantum Exchange to Create Technologically Transformative Ecosystem

The University of Chicago is collaborating with the U.S. Department of Energy's Argonne National Laboratory and Fermi National Accelerator Laboratory to launch an intellectual hub for advancing academic, industrial and governmental efforts in the science and engineering of quantum information.

Department of Energy Awards Six Research Contracts Totaling $258 Million to Accelerate U.S. Supercomputing Technology

Today U.S. Secretary of Energy Rick Perry announced that six leading U.S. technology companies will receive funding from the Department of Energy's Exascale Computing Project (ECP) as part of its new PathForward program, accelerating the research necessary to deploy the nation's first exascale supercomputers.

Cynthia Jenks Named Director of Argonne's Chemical Sciences and Engineering Division

Argonne has named Cynthia Jenks the next director of the laboratory's Chemical Sciences and Engineering Division. Jenks currently serves as the assistant director for scientific planning and the director of the Chemical and Biological Sciences Division at Ames Laboratory.

Argonne-Developed Technology for Producing Graphene Wins TechConnect National Innovation Award

A method that significantly cuts the time and cost needed to grow graphene has won a 2017 TechConnect National Innovation Award. This is the second year in a row that a team at Argonne's Center for Nanoscale Materials has received this award.

Honeywell UOP and Argonne Seek Research Collaborations in Catalysis Under Technologist in Residence Program

Researchers at Argonne are collaborating with Honeywell UOP scientists to explore innovative energy and chemicals production.

Follow the Fantastic Voyage of the ICARUS Neutrino Detector

The ICARUS neutrino detector, born at Gran Sasso National Lab in Italy and refurbished at CERN, will make its way across the sea to Fermilab this summer. Follow along using an interactive map online.

JSA Awards Graduate Fellowships for Research at Jefferson Lab

Jefferson Sciences Associates announced today the award of eight JSA/Jefferson Lab graduate fellowships. The doctoral students will use the fellowships to support their advanced studies at their universities and conduct research at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) - a U.S. Department of Energy nuclear physics laboratory managed and operated by JSA, a joint venture between SURA and PAE Applied Technologies.

Muon Magnet's Moment Has Arrived

On May 31, the 50-foot-wide superconducting electromagnet at the center of the Muon g-2 experiment saw its first beam of muon particles from Fermilab's accelerators, kicking off a three-year effort to measure just what happens to those particles when placed in a stunningly precise magnetic field. The answer could rewrite scientists' picture of the universe and how it works.

Seven Small Businesses to Collaborate with Argonne to Solve Technical Challenges

Seven small businesses have been selected to collaborate with researchers at Argonne to address technical challenges as part of DOE's Small Business Vouchers Program.

JSA Names Charles Perdrisat and Charles Sinclair as Co-Recipients of its 2017 Outstanding Nuclear Physicist Prize

Jefferson Science Associates, LLC, announced today that Charles Perdrisat and Charles Sinclair are the recipients of the 2017 Outstanding Nuclear Physicist Prize. The 2017 JSA Outstanding Nuclear Physicist Award is jointly awarded to Charles Perdrisat for his pioneering implementation of the polarization transfer technique to determine proton elastic form factors, and to Charles Sinclair for his crucial development of polarized electron beam technology, which made such measurements, and many others, possible.


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Oxygen: The Jekyll and Hyde of Biofuels

Scientists are devising ways to protect plants, biofuels and, ultimately, the atmosphere itself from damage caused by an element that sustains life on earth.

The Rise of Giant Viruses

Research reveals that giant viruses acquire genes piecemeal from others, with implications for bioenergy production and environmental cleanup.

Grasses: The Secrets Behind Their Success

Researchers find a grass gene affecting how plants manage water and carbon dioxide that could be useful to growing biofuel crops on marginal land.

New Perspectives Into Arctic Cloud Phases

Teamwork provides insight into complicated cloud processes that are important to potential environmental changes in the Arctic.

Mountaintop Plants and Soils to Become Out of Sync

Plants and soil microbes may be altered by climate warming at different rates and in different ways, meaning vital nutrient patterns could be misaligned.

If a Tree Falls in the Amazon

For the first time, scientists pinpointed how often storms topple trees, helping to predict how changes in Amazonia affect the world.

Turning Waste into Fuels, Microbial Style

A newly discovered metabolic process linking different bacteria in a community could enhance bioenergy production.

Department of Energy Awards Six Research Contracts Totaling $258 Million to Accelerate U.S. Supercomputing Technology

Today U.S. Secretary of Energy Rick Perry announced that six leading U.S. technology companies will receive funding from the Department of Energy's Exascale Computing Project (ECP) as part of its new PathForward program, accelerating the research necessary to deploy the nation's first exascale supercomputers.

Electrifying Magnetism

Researchers create materials with controllable electrical and magnetic properties, even at room temperature.

One Step Closer to Practical Fast Charging Batteries

Novel electrode materials have designed pathways for electrons and ions during the charge/discharge cycle.


Understanding Tungsten "Fuzz"

Article ID: 675839

Released: 2017-06-05 06:05:44

Source Newsroom: Department of Energy, Office of Science

  • Credit: Image courtesy of Oak Ridge National Laboratory

    Tungsten fuzz growth due to exposure to low energy helium plasma (left), akin to normal operations of a fusion reactor, and exposure to high energy helium plasma (right), emulating plasma disruptions.

The Science

When exposed to energetic helium bombardment as in the plasma-facing components of fusion devices, tungsten will grow a mat of “fuzz.” The fuzz is typically a few tens of nanometers in diameter and up to several microns in length. For comparison, a strand of human DNA is 2.5 nanometers in diameter and a red blood cell is 5 microns wide. Generally, the detailed mechanisms of growth and structure of these tendrils are not well understood. In this study, researchers grew tungsten “fuzz” and characterized it at a number of conditions. Their results help to validate and inform models and theoretical understanding.

The Impact

Tungsten “fuzz” is likely to have both beneficial and detrimental properties in terms of overall materials performance for fusion reactors. On the plus side, fuzzy tungsten is expected to take heat loads that would crack bulk tungsten. Also, erosion is orders of magnitudes less in fuzzy than in bulk tungsten. On the minus side, the fuzz, or nanotendrils, are fragile. They can break off, forming a dust that can cool the plasma. Until more is known about the tungsten fuzz, engineering these materials to eliminate the bad while accentuating the good is impossible. With this in mind, the researchers focused on understanding the fundamental behavior and degradation mechanisms of these plasma-facing materials. The ultimate goal is designing more robust materials for service in the harsh fusion environment.

Summary

Under helium plasma exposure in tokamak-relevant conditions, nanotendril “fuzz” will grow on tungsten plasma-facing components in a magnetic fusion energy device. Researchers at Oak Ridge National Laboratory, in conjunction with collaborators, have grown tungsten nanotendrils at varying helium bombardment energies and characterized them using electron microscopy. The scientists showed that exposure to both low and high-energy helium plasmas form narrow grass-like mats of tendrils. Tendrils grown under lower energy bombardment are both finer and smoother than those grown under high-energy bombardment. Additionally, the team showed that both families of tendrils are nanocrystalline with fine-scale cavities, believed to be helium bubbles, just a few nanometers in size. Finally, the team used electron diffraction to perform crystallographic mapping of the grains to gain insight into growth mechanisms of the fuzz. Although they observed no preferential growth axes or angles/axis pairs, patterns did emerge that indicate differing growth mechanisms depending on helium bombardment energy. Although the details of these mechanisms remain unresolved, the results presented here indicate engineering solutions to the amelioration of nanotendril growth, or surface degradation in general, will need to address multiple mechanisms of degradation.

 

Funding

This work was primarily supported by an Early Career Award, U.S. Department of Energy (DOE), Office of Science, Fusion Energy Sciences, under contract DE-AC05-00OR22725. Additional support was provided by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for DOE. Instrumentation support was provided by DOE, Office of Nuclear Energy, Fuel Cycle Research and Development Program and the Nuclear Science User Facilities.

Publications

K. Wang, R.P. Doerner, M.J. Baldwin, F.W. Meyer, M.E. Bannister, A. Darbal, R. Stroud, and C.M. Parish, “Morphologies of tungsten nanotendrils grown under helium exposureExternal link.” Scientific Reports 7, 42315 (2017). [DOI: 10.1038/srep42315]

K. Wang, M.E. Bannister, F.W. Meyer, and C.M. Parish, “Effect of starting microstructure on helium plasma-materials interactions in tungstenExternal link.” Acta Materialia 124, 556-567 (2017). [DOI: 10.1016/j.actamat.2016.11.042]

C.M. Parish, K. Wang, R.P. Doerner, and M.J. Baldwin, “Grain orientations and grain boundaries in tungsten nanotendril fuzz grown under divertor-like conditionsExternal link.” Scripta Materialia 127, 132-135 (2017). [DOI: 10.1016/j.scriptamat.2016.09.018]