Oak Ridge Today

ORNL paper examines clues for superconductivity in an iron-based material

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FERMI Figure

A change of Hall and Seebeck effects point to large Fermi surface modification at the structural transition, preventing superconductivity at low temperatures. The change in the Fermi surface topology has been confirmed by angle-resolved photoemission spectroscopy. (Image courtesy ORNL)

For the first time, scientists have a clearer understanding of how to control the appearance of a superconducting phase in a material, adding crucial fundamental knowledge and perhaps setting the stage for advances in the field of superconductivity.

The paper, published in Physical Review Letters, focuses on a calcium-iron-arsenide single crystal, which has structural, thermodynamic, and transport properties that can be varied through carefully controlled synthesis, similar to the application of pressure. To make this discovery, researchers focused on how these changes alter the material’s Fermi surface, which maps the specific population and arrangement of electrons in materials.

“The Fermi surface is basically the ‘genetic code’ for causing a certain property, including superconductivity, in a material,” said Athena Safa-Sefat of the U.S. Department of Energy’s Oak Ridge National Laboratory, which led the research team. “We can make different phases of this material in single crystal forms and measure their structure and properties, but now we have Fermi surface signatures that explain why we can’t induce superconductivity in a certain structural phase of this material.” [Read more…]

Thinner, flexible tablets, TVs possible through UT research, visiting ORNL scientist

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David Mandrus, Stephen Pennycook, and Jiaqing Yen

David Mandrus, Stephen Pennycook, and Jiaqiang Yan, from left, recently helped in a Vanderbilt-led project that could result in paper-thin, flexible tablets and TVs. (Photo courtesy University of Tennessee)

KNOXVILLE—Researchers from the University of Tennessee in Knoxville recently garnered national attention for their part in a study that could lead to the development of tablets, televisions, and mobile devices the width of a piece of paper.

First published in Nature, the article details how researchers have been able to create wires only three atoms wide using an electron beam.

The lead researcher on the project was Vanderbilt Ph.D. student Junhao Lin, who was a visiting scientist at Oak Ridge National Laboratory at the time.

Through the ORNL connection, UT’s Stephen Pennycook, David Mandrus, and Jiaqiang Yan—all of the College of Engineering’s Department of Materials Science and Engineering—got involved. [Read more…]

More than 100 jobs terminated as B&W work on USEC centrifuge project ends

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American Centrifuge Technology Manufacturing Center

The American Centrifuge Technology Manufacturing Center in south Oak Ridge is pictured above. (Photos courtesy USEC)

But hundreds of jobs maintained in Ohio and Tennessee, USEC says

Babcock and Wilcox has terminated the employment of more than 100 workers who had been involved in the American Centrifuge project with USEC, and Monday was the last day of work for most of them, a spokesperson said.

“B&W’s involvement in the American Centrifuge Manufacturing LLC has transitioned fully to USEC, which will result in the termination of all 122 employees B&W had engaged in the effort,” said Aimee Mills, B&W media relations lead.

Mills said roughly 25 employees will be released during the next two months as the “final steps of demobilization take place” on the advanced uranium enrichment project, which has included centrifuge manufacturing in Oak Ridge and the American Centrifuge Plant in Piketon, Ohio.

“Some of those affected have been reassigned within B&W,” Mills said. “We have also provided assistance by way of job fairs and workshops to update resumes.”

Meanwhile, USEC has notified a small group of its Oak Ridge employees who worked on manufacturing activities that they would be laid off, Communications Manager Jeremy Derryberry said Tuesday. Several were transferred to other parts of the centrifuge program. [Read more…]

‘Double-duty’ electrolyte enables new chemistry for longer-lived batteries

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ORNL Battery Chemistry

When ORNL researchers incorporated a solid lithium thiophosphate electrolyte into a lithium-carbon fluoride battery, the device generated a 26 percent higher capacity than what would be its theoretical maximum if each component acted independently. (Image courtesy ORNL)

 

Researchers at Oak Ridge National Laboratory have developed a new and unconventional battery chemistry aimed at producing batteries that last longer than previously thought possible.

In a study published in the Journal of the American Chemical Society, ORNL researchers challenged a long-held assumption that a battery’s three main components—the positive cathode, negative anode, and ion-conducting electrolyte—can play only one role in the device.

The electrolyte in the team’s new battery design has dual functions: It serves not only as an ion conductor but also as a cathode supplement. This cooperative chemistry, enabled by the use of an ORNL-developed solid electrolyte, delivers an extra boost to the battery’s capacity, and extends the lifespan of the device.

“This bi-functional electrolyte revolutionizes the concept of conventional batteries and opens a new avenue for the design of batteries with unprecedented energy density,” said ORNL’s Chengdu Liang. [Read more…]

Field work complete, cleanup projects used $751 million in Recovery Act funding

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Building K-33

Building K-33 at the East Tennessee Technology Park, also known as the former K-25 site, before demolition. (DOE photo)

 

Note: This story was updated at 5:30 p.m.

The field work is complete on 27 cleanup projects at three federal sites in Oak Ridge that used $751 million in Recovery Act funds.

The U.S. Department of Energy’s Oak Ridge Office of Environmental Management, or EM, announced the end of the field work on Thursday.

“We’re done knocking down buildings and with all the work in the field,” said Mike Koentop, executive officer in Oak Ridge Office of Environmental Management. “We have paperwork left to do to close out projects.”

The American Recovery and Reinvestment Act of 2009, also known as the Recovery Act or stimulus bill, was passed by Congress and signed by President Barack Obama in February 2009. It was meant to help stimulate an economic recovery during the depths of the Great Recession, and it was intended to address long-neglected infrastructure projects and programs.

In Oak Ridge, the Recovery Act funding paid for several demolition projects such as the demolition of the 1.4-million-square-foot K-33 Building at the East Tennessee Technology Park and other projects ranging from mercury reduction at the Y-12 National Security Complex to transuranic waste processing at Oak Ridge National Laboratory. [Read more…]

Urban design leader named newest UT-ORNL Governor’s Chair

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Phil Enquist

Phil Enquist

KNOXVILLE—Philip Enquist, partner in charge of urban design and planning and leader of the City Design Practice at Skidmore, Owings and Merrill, has been named the 16th University of Tennessee-Oak Ridge National Laboratory Governor’s Chair. Skidmore, Owings, and Merrill is one of the world’s leading urban planning, architecture, and engineering firms, a press release said.

Enquist and a select research team will serve as Governor’s Chair for High Performance Energy Practices in Urban Environments and will be affiliated with and administer projects through the UT College of Architecture and Design.

The Governor’s Chair team will be a research partnership among many designers at the firm who specialize in sustainable urbanism and high-performance buildings. Skidmore, Owings, and Merrill’s City Design Practice is the world’s most highly awarded urban planning group.

The contract between ORNL, UT, and the design firm is pending, the press release said. [Read more…]

Oak Ridge senior Andrew Skipper earns UT-Battelle scholarship

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Andrew Skipper and Thom Mason

Andrew Skipper, left, the 2014 UT-Battelle Scholarship winner, is congratulated by ORNL Director Thom Mason. (Submitted photo)

Andrew Skipper, a senior at Oak Ridge High School, is the recipient of the 2014 UT-Battelle Scholarship to the University of Tennessee.

The four-year, $20,000 scholarship is presented annually to a graduating senior who plans to study science, engineering, or mathematics at UT and whose mother or father works at Oak Ridge National Laboratory.

Andrew is the son of David and Maria Skipper. David Skipper works in ORNL’s Environmental Protection and Waste Services Division, and Maria Skipper works in ORNL’s Business Management Services Division. His grandmother, Margie Skipper, worked in ORNL’s Laboratory Protection Division for many years prior to her retirement in 1999.

Andrew’s goal at UT is to pursue a bachelor’s degree in chemical and biomolecular engineering before enrolling in graduate or medical school. [Read more…]

FORNL has third talk on international thermonuclear project on Tuesday

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Graeme Murdoch

Graeme Murdoch

Friends of Oak Ridge National Laboratory will have its third talk on the U.S. ITER project on Tuesday. ITER is the International Thermonuclear Experimental Reactor, and it will be constructed at Cadarache, France, and is expected to be completed within 10 years.

The Friends of ORNL lecture starts at noon Tuesday at the University of Tennessee Resource Center. It will feature Graeme Murdoch, who will discuss U.S. ITER non-nuclear systems.

“The United States has joined with China, the European Union, India, Japan, Korea, and Russia to construct and operate ITER, a full-scale, 500 megawatt experimental fusion device,” a press release said. “U.S. Contributions to ITER include hardware (with supporting research and development and design), personnel (U.S. engineers and scientists) to the ITER site in Cadarache, and cash contributions to the ITER organization. US-supplied hardware includes magnets, blankets, diagnostics, tritium processing, ion cyclotron and electron cyclotron heating and current drive systems, pellet fueling, and more conventional systems such as cooling water and electrical power systems.”

ITER is a large-scale project that presents many engineering challenges, the press release said. [Read more…]

DOE explores options for enriched uranium technology for national security

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American Centrifuge Technology Manufacturing Center

The American Centrifuge Technology Manufacturing Center in south Oak Ridge is pictured above. (Photos courtesy USEC)

USEC, UT-Battelle to preserve centrifuge enrichment capabilities on interim basis

USEC and UT-Battelle have signed a $33.7 million, five-month contract to continue operating centrifuges and conducting research and development activities on a uranium enrichment project deemed important for national security and possible commercial use.

The agreement with UT-Battelle, which manages Oak Ridge National Laboratory, was signed May 1. The five-month term ends Sept. 30. The new agreement includes options for two six-month extensions valued at about $41.7 million each. The total price of the contract with the options is roughly $117 million.

USEC, which is now an ORNL subcontractor, previously performed research, development, and demonstration work on the project, the American Centrifuge Project, under an agreement with the U.S. Department of Energy that had been in place since June 12, 2012. That cost-sharing agreement expired April 30. [Read more…]

Society of Automotive Engineers honors Storey, Wagner, Sluder

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Robert Wagner, John Storey, and Scott Sluder

The Society of Automotive Engineers has honored ORNL researchers, from left, Robert Wagner, John Storey, and Scott Sluder. (Submitted photo)

Three researchers from the Fuels, Engines, and Emissions Research Center at Oak Ridge National Laboratory received major awards at the recent Society of Automotive Engineers World Congress.

John Storey was elected an SAE Fellow. The fellowship is the highest level of SAE membership, honoring significant contributions to the automotive field.

Storey was recognized for pioneering new techniques in the characterization of particulate matter and exhaust emissions and for leading a critical sub-committee for the diesel fuel sulfur rule. SAE International also recognized Storey for multiple contributions to the development of lean exhaust emissions control. [Read more…]

‘Atomic switcheroo’ explains origins of thin-film solar cell mystery

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Current Maps

Cross-sectional electron beam-induced current maps show the difference in cadmium telluride solar cells before (pictured above) and after (below) cadmium chloride treatment. The increased brightness after treatment indicates higher current collection at the grain boundaries. (Submitted photo)

Treating cadmium-telluride (CdTe) solar cell materials with cadmium-chloride improves their efficiency, but researchers have not fully understood why. Now, an atomic-scale examination of the thin-film solar cells led by Oak Ridge National Laboratory has answered this decades-long debate about the materials’ photovoltaic efficiency increase after treatment.

A research team from ORNL, the University of Toledo, and the U.S. Department of Energy’s National Renewable Energy Laboratory used electron microscopy and computational simulations to explore the physical origins of the unexplained treatment process. The results are published in Physical Review Letters, or PRL.

Thin-film CdTe solar cells are considered a potential rival to silicon-based photovoltaic systems because of their theoretically low cost per power output and ease of fabrication. Their comparatively low historical efficiency in converting sunlight into energy, however, has limited the technology’s widespread use, especially for home systems. [Read more…]

Student at UT’s Bredesen Center wins $50,000 ORNL prize

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Andrew Lepore Big Idea ORNL Check

Bredesen Center student Andrew Lepore stands with the $50,000 check he won as part of Oak Ridge National Laboratory’s Next Big Idea competition. (Photo courtesy University of Tennessee)

KNOXVILLE—With the first set of Bredesen Center graduates at the University of Tennessee set to receive their doctorates next week, students who will be in the next wave of graduates are already finding success.

Andrew Lepore, working out of the Materials Science and Technology Division through the center, recently won a prestigious Oak Ridge National Laboratory-related prize at the Next Big Idea competition. Lepore is on track to receive his doctorate in 2016.

“For him to go in there against some more seasoned researchers, against students who are further along, and come out with one of the three awards speaks highly of him and of the quality of students we have here,” said Bredesen Center Director Lee Riedinger. [Read more…]