image: Scientists used neutrons produced at Oak Ridge National Laboratory to discover the molecular mechanism responsible for the flow in a hydrogen-bonding liquid. view more
Credit: Jill Hemman/Oak Ridge National Laboratory, U.S. Dept. of Energy
Datasets - Supporting hurricane damage assessments
Geospatial scientists at Oak Ridge National Laboratory have developed a novel method to quickly gather building structure datasets that support emergency response teams assessing properties damaged by Hurricanes Harvey and Irma. By coupling deep learning with high-performance computing, ORNL collected and extracted building outlines and roadways from high-resolution satellite and aerial images. As hurricanes formed in the Gulf Coast and the Atlantic Ocean, ORNL activated their technique. "During devastating weather events, it's difficult and time consuming to assess damage manually," said ORNL's Mark Tuttle. "Our method supports emergency response efforts by providing preliminary building structure data--which can be categorized for residential, multi-family and commercial properties--on the county level, and this has been applied for hurricane-impacted areas of Texas, Florida, Puerto Rico and other U.S. Caribbean territories." During Hurricane Harvey, ORNL analyzed nearly 2,000 images covering nearly 26,000 square miles of building structures in Texas' coastal counties in just 24 hours, a process that would typically take up to nine months. [Contact: Sara Shoemaker, (865) 576-9219; shoemakerms@ornl.gov]
Image #1: https://www.ornl.gov/sites/default/files/01%201%20-%20Impacts.jpg
Caption #1: As hurricanes formed in the Gulf Coast, ORNL activated a computing technique to quickly gather building structure data from Texas' coastal counties. Credit: Mark Tuttle/Oak Ridge National Laboratory, U.S. Dept. of Energy
Image #2: https://www.ornl.gov/sites/default/files/01%202%20-%20Texas_coastal_counties_ORNL.jpg
Caption #2: ORNL's novel computing method supports emergency response efforts by providing preliminary building structure data on the county level. This technique has been applied for hurricane-impacted areas of Texas, Florida, Puerto Rico and other U.S. Caribbean territories. Credit: Mark Tuttle/Oak Ridge National Laboratory, U.S. Dept. of Energy
Neutrons - Go with the flow
Using neutrons produced at Oak Ridge National Laboratory, scientists discovered the molecular mechanism responsible for the flow in a hydrogen-bonding liquid, which has similar characteristics to the molecular motions in organic molecules such as DNA and proteins. Their observation demonstrates Maxwell's Law, which relates how fast molecules inside a liquid rearrange to flow with a syrupy or water-like viscosity. "Maxwell's theory was confirmed long ago for many liquids, but hydrogen-bonding liquids were a complicated exception," University of Cincinnati professor Jonathan Nickels said. "We unexpectedly discovered that flow in this liquid was connected to fluctuations in the hydrogen-bond network connectivity, rather than the dynamics of molecular collisions or the fluctuations of H-bonds themselves." Understanding this mechanism will help scientists develop safe and more environmentally friendly solvents and advance protein and water research for biomedical applications. The team used ORNL's Spallation Neutron Source, a DOE user facility. Nickels' team, including coauthors Stefania Perticaroli and Barmak Mostofian, published their findings in the Journal of Physical Chemistry Chemical Physics. [Contact: Kelley Smith, (865) 576-5668; smithks@ornl.gov]
Image: https://www.ornl.gov/sites/default/files/news/images/02%20-%2017-G01000_PCCP_Nickels.jpg
Caption: Scientists used neutrons produced at Oak Ridge National Laboratory to discover the molecular mechanism responsible for the flow in a hydrogen-bonding liquid. Credit: Jill Hemman/Oak Ridge National Laboratory, U.S. Dept. of Energy
Video: https://youtu.be/9hCI3E4dKXY
Video caption: This video shows the rearrangement of the molecular backbone and hydrogen bonds in a green solvent. Credit: Jonathan Nickels, University of Cincinnati
Materials - Ripple effect
A semiconducting material with a puckered pentagonal atomic structure, characterized by Oak Ridge National Laboratory, could rival graphene and black phosphorus as a viable option for nanoscale electronics. The ORNL-led team studied a novel two-dimensional, or atomic-thin, layered material called palladium diselenide, or PdSe2. The team unveiled that the atoms of the material chemically bond in five-sided structures. This causes the resulting layers to "pucker" and makes the material exhibit properties that could benefit future optoelectronics. "The band gap of the material changed significantly as we exfoliated layers of PdSe2 from a bulk crystal," ORNL's Kai Xiao said. "The ability to tune the material's band gap from zero in the bulk to approximately 1.3 electron volts in the monolayer opens exciting new options for nanoelectronics." The team published their work in the Journal of the American Chemical Society and plans to grow scalable, large-area 2D PdSe2 crystals. [Contact: Sara Shoemaker, (865) 576-9219; shoemakerms@ornl.gov]
Image: https://www.ornl.gov/sites/default/files/news/images/03%20-%20Materials-Five-sided_phenom_ORNL.jpg
Caption: A novel, two-dimensional material "puckers" because its structure is composed of atoms that tile in the famous Cairo pentagonal pattern, opening exciting new opportunities for nanoelectronics. Credit: Christopher Rouleau and Kai Xiao/Oak Ridge National Laboratory, U.S. Dept. of Energy
Refrigerants - Cooling with propane
Cooling homes and small office spaces could become less costly and more efficient with new early stage technology developed by Oak Ridge National Laboratory. Researchers designed a window air conditioning unit that uses propane as the refrigerant, cooling the air with 17 percent higher efficiency than the best ENERGY STAR® commercial units. "Propane offers superior thermodynamic properties and creates 700 percent less pollution than standard refrigerants," said ORNL's Brian Fricke. "We developed a system that takes advantage of these qualities and reduces global warming potential." The team's early-stage technology includes a novel heat exchanger, compressor and controls that require less propane than similar units used overseas. The team's laboratory evaluations demonstrate the prototype unit is the first propane window air conditioner to meet U.S. building safety standards. [Contact: Kim Askey, (865) 946-1861; askeyka@ornl.gov]
Image: https://www.ornl.gov/sites/default/files/news/images/04%20-%20Bo_Shen_ORNL.jpg
Caption: Oak Ridge National Laboratory's Bo Shen works with a prototype window air conditioning unit that cools using propane, which lowers costs, increases efficiency and benefits the environment. Credit: Jason Richards/Oak Ridge National Laboratory, U.S. Dept. of Energy
Semiconductors - Making contact
A new approach developed by Oak Ridge National Laboratory creates seamless electrical contacts between precisely controlled nanoribbons of graphene, making the material viable as a building block for next-generation electronic devices. In a recent study, an ORNL-led team grew the popular, atomic-thick semi-metallic graphene material as semiconducting ribbons, constructed from the bottom up using a precise number of atoms across and a precise molecular structure at the edge. To be more useful in electronics, the team focused efforts on forming seamless interfaces between ribbons with different widths, which created a staircase configuration. "This novel configuration allows us to adjust the energy gap, tune the energy level alignment and direct the flow of electricity through the materials," said An-Ping Li, ORNL coauthor of a study published in Nano Letters that describes the approach. [Contact: Sara Shoemaker, (865) 576-9219; shoemakerms@ornl.gov]
Image: https://www.ornl.gov/sites/default/files/news/images/05%20-%20Staircase_ORNL_combined.jpg
Caption: An ORNL-led team formed seamless interfaces between graphene ribbons with different widths, creating a staircase configuration. This configuration has seamless electrical contacts, making the material viable as a building block for next-generation electronic devices. Credit: Chuanxu Ma and An-Ping Li/Oak Ridge National Laboratory, U.S. Dept. of Energy
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Journal
Zeitschrift für Physikalische Chemie/International journal of research in physical chemistry and chemical physics