Story tips from the Department of Energy’s Oak Ridge National Laboratory, November 2018

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Credit: Oak Ridge National Laboratory, US Dept. of Energy

Transportation–Going with the flow

Self-driving cars promise to keep traffic moving smoothly and reduce fuel usage, but proving those advantages has been a challenge with so few connected and automated vehicles, or CAVs, currently on the road. To study the potential benefits, researchers at Oak Ridge National Laboratory developed a simulation framework that analyzes the impact of partial market penetration of CAVs on fuel consumption, travel time and traffic flow in a merging on-ramp scenario under low, medium and heavy traffic volumes. "We observed that an increased number of CAVs communicating and coordinating driving activity stabilize traffic flow and, depending on the traffic volume, can reduce fuel use by more than 40 percent," said ORNL's Jacky Rios-Torres. "A steady traffic pattern, in turn, improves travel time." Future research will explore the impact of CAVs in various traffic scenarios and determine whether CAVs can indirectly influence the driving performance of human-driven cars. The team's results were published in IEEE Transactions on Intelligent Vehicles. [Contact: Jennifer Burke, (865) 576-3212; [email protected]]

Image: https://www.ornl.gov/sites/default/files/Autonomous_vehicle_simulation_ORNL.jpg

Caption: ORNL researchers created a simulation framework to study how coordinated connected and automated vehicles could improve traffic flow and reduce energy consumption during a merging on-ramp scenario while interacting with human drivers. Credit: Oak Ridge National Laboratory, U.S. Dept. of Energy

Physics–Elements at extremes

In neutron star mergers and supernovae, lighter elements absorb neutrons to create heavier elements whose nuclei are neutron-rich and radioactive. To better understand this phenomenon, physicists turned to the "doubly magic" tin isotope Sn-132, colliding it with a target at Oak Ridge National Laboratory to assess its properties as it lost a neutron to become Sn-131. The results, published after years of complex data analysis, were combined with a prior experiment in which a nucleus of Sn-132 gained a neutron to become Sn-133. "Many ambiguities are reduced by systematically studying the addition and subtraction of neutrons," said ORNL's Steven Pain. "This is the first time this technique has been applied to such a heavy neutron-rich nucleus. These results will help benchmark theoretical models and guide future investigations of unstable nuclei with even greater neutron surpluses." The experiment was the last conducted at ORNL's Holifield Radioactive Ion Beam Facility before it ceased operations in 2012. [Contact: Dawn Levy, (865) 576-6448; [email protected]]

Image: https://www.ornl.gov/sites/default/files/Physics_silicon-detectors.jpg

Caption: Position-sensitive silicon detectors form the "nerves" of the Super Oak Ridge Rutgers University Barrel Array and yield high spatial resolution that enabled the Sn-132 experiment at ORNL–the first neutron-removal reaction on such a heavy, neutron-rich nucleus. The array, installed at Michigan State University, should begin operations in 2022. Credit: Steven Pain/Oak Ridge National Laboratory, U.S. Dept. of Energy

Grid–Balancing act

Oak Ridge National Laboratory scientists have devised a method to control the heating and cooling systems of a large network of buildings for power grid stability–all while ensuring the comfort of occupants. Buildings consume about 73 percent of the nation's electricity and about half of that is for heating, ventilation and air conditioning systems. Harnessing the HVAC-related demand of a fleet of buildings "can make a difference in frequency regulation," or what grid operators refer to as the balance between electricity supply and demand, said ORNL's Mohammed Olama. "We developed control schemes that don't require a large number of calculations and can be implemented easily on existing HVAC systems that have simple on-off controls." Simulations found that the controls are successful in providing frequency regulation from a fleet of 50 buildings, while keeping indoor temperatures within 0.5 degrees Celsius of a set range. The research is detailed in the journal Energies. [Contact: Stephanie Seay, (865) 576-9894; [email protected]]

Image: https://www.ornl.gov/sites/default/files/hvac_grid03.png

Caption: ORNL scientists have devised a control architecture for a fleet of HVAC units, which could allow utilities to harness the demand from a city's worth of buildings to help balance the power grid. The research is funded by DOE's Building Technologies Office. Credit: Andy Sproles/Oak Ridge National Laboratory, U.S. Dept. of Energy

Neutrons–Gentle strain

Scientists from AK Steel Corporation are using neutrons at Oak Ridge National Laboratory's Spallation Neutron Source to discover how different manufacturing processes will affect the performance of the company's new AHSS, or advanced high strength steel, called NEXMET 1000. Neutrons, unlike electrons or X-rays, are highly penetrating, non-destructive and sensitive to lighter elements, making them an ideal probe for this novel category of steel materials. "The VULCAN instrument at SNS provides information about the crystal structure of AHSS during different stages of the stamping process that we cannot get anywhere else in the United States," said Wei Wu of AK Steel. "This data will be vital to improving our manufacturing methods and will make it easier to quickly identify the best new materials to blend with NEXMET® 1000 to produce lighter, safer and more durable automotive components." [Contact: Kelley Smith, (865) 576-5668; [email protected]]

Image: https://www.ornl.gov/sites/default/files/AK_Steel_story-tip.jpg

Caption: AK Steel Corporation scientist Wei Wu holds a sample of the company's new advanced high strength steel. Wu is using neutrons to study how the material is affected by various manufacturing processes to produce automotive components that improve fuel efficiency, last longer and are safer. Credit: Kelley Smith/Oak Ridge National Laboratory, U.S. Department of Energy

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Sara Shoemaker
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