X
X
X

Filters:

How X-Rays Helped to Solve Mystery of Floating Rocks

Experiments at Berkeley Lab's Advanced Light Source have helped scientists to solve a mystery of why some rocks can float for years in the ocean, traveling thousands of miles before sinking.

Special X-Ray Technique Allows Scientists to See 3-D Deformations

In a new study published last Friday in Science, researchers at Argonne used an X-ray scattering technique called Bragg coherent diffraction imaging to reconstruct in 3-D the size and shape of grain defects. These defects create imperfections in the lattice of atoms inside a grain that can give rise to interesting material properties and effects.

Neptune: Neutralizer-Free Plasma Propulsion

The most established plasma propulsion concepts are gridded-ion thrusters that accelerate and emit a larger number of positively charged particles than those that are negatively charged. To enable the spacecraft to remain charge-neutral, a "neutralizer" is used to inject electrons to exactly balance the positive ion charge in the exhaust beam. However, the neutralizer requires additional power from the spacecraft and increases the size and weight of the propulsion system. Researchers are investigating how the radio-frequency self-bias effect can be used to remove the neutralizer altogether, and they report their work in this week's Physics of Plasmas.

Report Sheds New Insights on the Spin Dynamics of a Material Candidate for Low-Power Devices

In a report published in Nano LettersArgonne researchers reveal new insights into the properties of a magnetic insulator that is a candidate for low-power device applications; their insights form early stepping-stones towards developing high-speed, low-power electronics that use electron spin rather than charge to carry information.

Researchers Find Computer Code That Volkswagen Used to Cheat Emissions Tests

An international team of researchers has uncovered the mechanism that allowed Volkswagen to circumvent U.S. and European emission tests over at least six years before the Environmental Protection Agency put the company on notice in 2015 for violating the Clean Air Act. During a year-long investigation, researchers found code that allowed a car's onboard computer to determine that the vehicle was undergoing an emissions test.

Physicists Discover That Lithium Oxide on Tokamak Walls Can Improve Plasma Performance

A team of physicists has found that a coating of lithium oxide on the inside of fusion machines known as tokamaks can absorb as much deuterium as pure lithium can.

Scientists Perform First Basic Physics Simulation of Spontaneous Transition of the Edge of Fusion Plasma to Crucial High-Confinement Mode

PPPL physicists have simulated the spontaneous transition of turbulence at the edge of a fusion plasma to the high-confinement mode that sustains fusion reactions. The research was achieved with the extreme-scale plasma turbulence code XGC developed at PPPL in collaboration with a nationwide team.

Green Fleet Technology

New research at Penn State addresses the impact delivery trucks have on the environment by providing green solutions that keep costs down without sacrificing efficiency.

Scientists Demonstrate New Real-Time Technique for Studying Ionic Liquids at Electrode Interfaces

This electron microscope-based imaging technique could help scientists optimize the performance of ionic liquids for batteries and other energy storage devices.

How Scientists Turned a Flag Into a Loudspeaker

A paper-thin, flexible device created at Michigan State University not only can generate energy from human motion, it can act as a loudspeaker and microphone as well, nanotechnology researchers report in the May 16 edition of Nature Communications.


Filters:

Rensselaer Polytechnic Institute Graduates Urged to Embrace Change at 211th Commencement

Describing the dizzying pace of technological innovation, former United States Secretary of Energy Ernest J. Moniz urged graduates to "anticipate career change, welcome it, and manage it to your and your society's benefit" at the 211th Commencement at Rensselaer Polytechnic Institute (RPI) Saturday.

ORNL Welcomes Innovation Crossroads Entrepreneurial Research Fellows

Oak Ridge National Laboratory today welcomed the first cohort of innovators to join Innovation Crossroads, the Southeast region's first entrepreneurial research and development program based at a U.S. Department of Energy national laboratory.

Department of Energy Secretary Recognizes Argonne Scientists' Work to Fight Ebola, Cancer

Two groups of researchers at Argonne earned special awards from the office of the U.S. Secretary of Energy for addressing the global health challenges of Ebola and cancer.

Jefferson Science Associates, LLC Recognized for Leadership in Small Business Utilization

Jefferson Lab/Jefferson Science Associates has a long-standing commitment to doing business with and mentoring small businesses. That commitment and support received national recognition at the 16th Annual Dept. of Energy Small Business Forum and Expo held May 16-18, 2017 in Kansas City, Mo.

Rensselaer Polytechnic Institute President's Commencement Colloquy to Address "Criticality, Incisiveness, Creativity"

To kick off the Rensselaer Polytechnic Institute Commencement weekend, the annual President's Commencement Colloquy will take place on Friday, May 19, beginning at 3:30 p.m. The discussion, titled "Criticality, Incisiveness, Creativity," will include the Honorable Ernest J. Moniz, former Secretary of Energy, and the Honorable Roger W. Ferguson Jr., President and CEO of TIAA, and will be moderated by Rensselaer President Shirley Ann Jackson.

ORNL, University of Tennessee Launch New Doctoral Program in Data Science

The Tennessee Higher Education Commission has approved a new doctoral program in data science and engineering as part of the Bredesen Center for Interdisciplinary Research and Graduate Education.

SurfTec Receives $1.2 Million Energy Award to Develop Novel Coating

The Department of Energy has awarded $1.2 million to SurfTec LLC, a company affiliated with the U of A Technology Development Foundation, to continue developing a nanoparticle-based coating to replace lead-based journal bearings in the next generation of electric machines.

Ames Laboratory Scientist Inducted Into National Inventors Hall of Fame

Iver Anderson, senior metallurgist at Ames Laboratory, has been inducted into the National Inventors Hall of Fame.

DOE HPC4Mfg Program Funds 13 New Projects to Improve U.S. Energy Technologies Through High Performance Computing

A U.S. Department of Energy (DOE) program designed to spur the use of high performance supercomputers to advance U.S. manufacturing is funding 13 new industry projects for a total of $3.9 million.

Penn State Wind Energy Club Breezes to Victory in Collegiate Wind Competition

The Penn State Wind Energy Club breezed through the field at the U.S. Department of Energy Collegiate Wind Competition 2017 Technical Challenge, held April 20-22 at the National Wind Technology Center near Boulder, Colorado--earning its third overall victory in four years at the Collegiate Wind Competition.


Filters:

Casting a Wide Net

Designed molecules will provide positive impacts in energy production by selectively removing unwanted ions from complex solutions.

New Software Tools Streamline DNA Sequence Design-and-Build Process

Enhanced software tools will accelerate gene discovery and characterization, vital for new forms of fuel production.

The Ultrafast Interplay Between Molecules and Materials

Computer calculations by the Center for Solar Fuels, an Energy Frontier Research Center, shed light on nebulous interactions in semiconductors relevant to dye-sensitized solar cells.

Supercapacitors: WOODn't That Be Nice

Researchers at Nanostructures for Electrical Energy Storage, an Energy Frontier Research Center, take advantage of nature-made materials and structure for energy storage research.

Groundwater Flow Is Key for Modeling the Global Water Cycle

Water table depth and groundwater flow are vital to understanding the amount of water that plants transmit to the atmosphere.

Finding the Correct Path

A new computational technique greatly simplifies the complex reaction networks common to catalysis and combustion fields.

Opening Efficient Routes to Everyday Plastics

A new material from the Inorganometallic Catalyst Design Center, an Energy Frontier Research Center, facilitates the production of key industrial supplies.

Fight to the Top: Silver and Gold Compete for the Surface of a Bimetallic Solid

It's the classic plot of a buddy movie. Two struggling bodies team up to drive the plot and do good together. That same idea, when it comes to metals, could help scientists solve a big problem: the amount of energy consumed by making chemicals.

Saving Energy Through Light Control

New materials, designed by researchers at the Center for Excitonics, an Energy Frontier Research Center, can reduce energy consumption with the flip of a switch.

Teaching Perovskites to Swim

Scientists at the ANSER Energy Frontier Research Center designed a two-component layer protects a sunlight-harvesting device from water and heat.


Finding the Correct Path

Article ID: 673990

Released: 2017-05-02 11:05:45

Source Newsroom: Department of Energy, Office of Science

  • Credit: Image courtesy of Ulissi et al. Nature Communications 8, 14621 (2017)

    Seemingly simple reactions, such as the reaction of syngas (carbon monoxide (CO) and hydrogen) on a rhodium surface to convert fossil and biomass resources into chemicals and fuels, can have hundreds of species and reactions within their reaction network. This creates thousands of potential reaction pathways, which would be very time consuming to individually investigate with high-performance computer simulations. Machine-learning techniques predict the most important reactions with a small number of simulations.

The Science

Turning fossil resources or biomass into fuels and countless other chemical reaction networks often involves hundreds of different species and reactions. The networks result in thousands of potential pathways for a reaction to proceed. A new computational technique uses machine-learning techniques and thermochemistry data to readily eliminate unlikely paths. Further, the technique reveals a subset of the most important pathways. More intensive computational methods can then be applied to only the important pathways.

The Impact

Decreasing the number of intensive calculations needed to identify reaction paths saves both researcher time and expensive high-performance computational resources. In addition, focusing the computation on key pathways improves the accuracy of the reaction network models. This new technique benefits all fields of chemistry that involve large reaction networks. Specifically, the technique benefits catalysis and combustion.

Summary

Identifying the correct mechanism of a reaction can still be one of the toughest tasks facing chemists. For example, when designing a catalyst, researchers must know which mechanism will occur in order to achieve the desired product. Additionally, the researcher will seek to minimize both undesirable side-products and the energy required to carry out the reaction. However, even a seemingly simple reaction can have thousands of possible pathways to reach a specific product. Fortunately, in most cases, only small portions of the possible pathways are relevant to the reaction. These important pathways are known as the rate-limiting steps. By focusing theoretical simulation efforts initially on identifying these important rate-limiting paths, researchers have reduced the time and computing resources needed to perform detailed investigations of very large reaction networks. This new technique uses approximations based on thermochemical and kinetic energy data to exclude clearly unfavorable sections of the reaction network. Intensive computational calculations are then applied to the remaining pathways, which represent the rate-limiting elementary reactions. Excluding the unnecessary sections of the reaction network allows the rate-limiting pathways to be studied in detail but now requires a significantly smaller number of intense calculations be carried out on high-performance computers, thus saving a great deal of researcher time and computer resources. Specifically, the researchers, from the SUNCAT Center for Interface Science and Catalysis and the Georgia Institute of Technology, applied this method to the reaction of syngas (carbon monoxide and hydrogen) on a rhodium(111) surface, a reaction scientists are developing to convert fossil and biomass resources to useful chemicals and fuels. Using the described method, the team determined the most likely reaction mechanism used far fewer intense calculations than previously possible. This technique is broadly applicable to virtually any reaction network and could improve computational methods for all fields of chemistry.

Funding

Funding was provided by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences to the SUNCAT Center for Interface Science and Catalysis. Additionally, A.J.M. was supported by the Department of Defense through the National Defense Science & Engineering Graduate Fellowship Program.

Publication

Z.W. Ulissi, A.J. Medford, T. Bligaard, and J.K. Nørskov, “To address surface reaction network complexity using scaling relations machine learning and DFT calculationsExternal link.” Nature Communications 8, 14621 (2017). [DOI: 10.1038/ncomms14621]