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PUBLIC RELEASE DATE:
1-Dec-2011

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Contact: Ron Walli
wallira@ornl.gov
865-576-0226
DOE/Oak Ridge National Laboratory
@ORNL

Story tips from the Department of Energy's Oak Ridge National Laboratory, Dec. 2011

To arrange for an interview with a researcher, please contact the Communications and External Relations staff member identified at the end of each tip. For more information on ORNL and its research and development activities, please refer to one of our Media Contacts. If you have a general media-related question or comment, you can send it to news@ornl.gov.

CYBERSECURITY -- Foiling exfiltration . . .

Computer hackers could lose a huge advantage because of a system being developed by a team led by Justin Beaver of Oak Ridge National Laboratory. "As we have seen in recent months, attackers who breach a system's defense have a distinct advantage because their presence is difficult to detect, they have a window into potentially sensitive data and their true identity and location are hidden," Beaver said. The ORNL technology detects exfiltration, or the unauthorized release of data, through the analysis of a user's behavior. In response, the system isolates a malicious user from access to any sensitive data by diverting the attacker to a virtual host. [Contact: Ron Walli, 865-576-0226; wallira@ornl.gov]

ENERGY -- Inexpensive renewable hydrogen . . .

Solar and wind energy could become more viable because of an innovation that produces a hydrogen stream of greater than 99 percent purity without using the more traditional proton-conducting polymers. This allows electricity generated by solar panels or wind turbines to feed the electrolyzers that produce hydrogen gas, which is then fed into a biofuels reactor for the production of liquid biofuels. Making this possible is a new materials and structural approach to electrolytic hydrogen production. Using modern lithographic techniques, a team led by Oak Ridge National Laboratory's Ivan Kravchenko fabricated porous silicon and plastic wafer barriers that serve as both proton conductors and electrode surface supports. Kravchenko demonstrated the feasibility of this approach using a 30-centimeter prototype design tower that separated the flow of hydrogen and oxygen bubbles. [Contact: Ron Walli, 865-576-0226; wallra@ornl.gov]

MAGNETISM -- Chilling discovery . . .

Something odd happens when you expose the element gadolinium to a strong magnetic field: Its temperature jumps up. Remove the field and the temperature drops below the starting point. This behavior, known as the magnetocaloric effect, is usually found in ferromagnets, materials that lose their magnetism above a certain temperature. If it can be exploited it will prove very useful in refrigerators and air conditioners that no longer need motorized compressors and special refrigerants. Oak Ridge National Laboratory's Markus Eisenbach and colleagues are using ORNL's Jaguar supercomputer to push forward on a very important part of this puzzle. Using an application that took the 2009 Gordon Bell Prize as the world's most advanced scientific application, Eisenbach's team has been simulating the magnetic properties of promising materials, focusing in particular on the magnetocaloric effect. Its work is detailed in three recent papers in the Journal of Applied Physics. (http://jap.aip.org/resource/1/japiau/v109/i7/p07E161_s1, http://jap.aip.org/resource/1/japiau/v109/i7/p07E138_s1, http://jap.aip.org/resource/1/japiau/v109/i7/p07A942_s1) [Contact: Leo Williams, 865-574-8891; williamsjl2@ornl.gov]

MATERIALS -- Rebuffing temperatures . . .

Carefully combining materials that shrink when heated with materials that expand creates a material unaffected by extreme temperature. Researchers can apply this concept to satellites that experience drastic temperature changes as they orbit the Earth but must also maintain precise data. Researchers at the California Institute of Technology combined data from Oak Ridge National Laboratory's Spallation Neutron Source with computer modeling to discover the origin of negative thermal expansion from fourth order potentials in cubic scandium tri-fluoride - one of the few materials that shrink when exposed to heat. ORNL's Doug Abernathy contributed to these findings, which appear in a paper recently published in Physical Review Letters. Understanding the phenomenal properties of this material helps scientists design materials with more desirable temperature properties. [Contact: Emma Macmillan, 865-241-9515; macmillanee@ornl.gov]

DIESEL -- Greater expectations . . .

A recent study of diesel particulate filter performance has revealed positive news for manufacturers and industry, indicating longer service lifetime expectations than ever before. Critical to vehicle emissions control, the filter removes soot and particulates from diesel exhaust. Under excessive stress, it can crack and fail -- yet the technology very often outlasts manufacturer warranties. Exploring the low failure rate, Oak Ridge National Laboratory and General Motors researchers found the apparent elastic modulus of the filter ceramics to be almost an order of magnitude lower than industry-accepted values. According to ORNL's Andrew Wereszczak, "The measurements indicate that while the filter is under thermally-induced strain, such as during regeneration, the actual internal stresses are much lower and mechanical reliability is much higher than manufacturer models have predicted in the past." [Contact: Kathy Graham, 865-946-1861; grahamkj@ornl.gov]

MATERIALS -- Conductive at the core . . .

Adaptive one-dimensional wires operating at 1 volt could eventually pave the way for oxide electronics, such as electronic devices that mimic human brain function. Using the piezoresponse force microscopy technique, researchers at Oak Ridge National Laboratory artificially arranged ferroelectric polarization in a "tornado"-like vortex pattern and discovered enhanced conductivity through the center. ORNL's Sergei Kalinin said these one-dimensional wires are essential for creating high-density electronics with less wasted power and faster operations. Nina Balke, the lead author on the paper, believes these findings will help researchers study new states of matter induced by unusual polarization patterns, ultimately helping create fundamentally new materials and devices. The results of this research are published in Nature Physics. [Contact: Emma Macmillan, 865-241-9515; macmillanee@ornl.gov]

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