New Technology to Speed Cleanup of Nuclear Contaminated Sites

A patent has been granted on this new type of radiation spectrometer, and the first production of devices will begin soon. The advance has also led to creation of a Corvallis-based spinoff company, Avicenna Instruments, based on the OSU research. The market for these instruments may ultimately be global, and thousands of them could be built, researchers say.

Hundreds of millions of dollars are spent on cleanup of some major sites contaminated by radioactivity, primarily from the historic production of nuclear weapons during and after World War II. These include the Hanford site in Washington, Savannah River site in South Carolina, and Oak Ridge National Laboratory in Tennessee.

"Unlike other detectors, this spectrometer is more efficient, and able to measure and quantify both gamma and beta radiation at the same time," said David Hamby, an OSU professor of health physics."Before this two different types of detectors and other chemical tests were needed in a time-consuming process."

"This system will be able to provide accurate results in 15 minutes that previously might have taken half a day," Hamby said."That saves steps, time and money."

The spectrometer, developed over 10 years by Hamby and Abi Farsoni, an assistant professor in the College of Engineering, can quickly tell the type and amount of radionuclides that are present in something like a soil sample -- contaminants such as cesium 137 or strontium 90 -- that were produced from reactor operations. And it can distinguish between gamma rays and beta particles, which is necessary to determine the level of contamination.

"Cleaning up radioactive contamination is something we can do, but the process is costly, and often the question when working in the field is how clean is clean enough," Hamby said."At some point the remaining level of radioactivity is not a concern. So we need the ability to do frequent and accurate testing to protect the environment while also controlling costs."

This system should allow that, Hamby said, and may eventually be used in monitoring processes in the nuclear energy industry, or possibly medical applications in the use of radioactive tracers.

The OSU College of Engineering has contracted with Ludlum Instruments, a Sweetwater, Texas, manufacturer, to produce the first instruments, and the OSU Office of Technology Transfer is seeking a licensee for commercial development. The electronic systems for the spectrometers will be produced in Oregon by Avicenna Instruments, the researchers said.

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New Cognitive Robotics Lab Tests Theories of Human Thought

"The real world has a lot of inconsistency that humans handle almost without noticing -- for example, we walk on uneven terrain, we see in shifting light," said Professor Vladislav Daniel Veksler, who is currently teaching Cognitive Robotics."With robots, we can see the problems humans face when navigating their environment."

Cognitive Robotics marries the study of cognitive science -- how the brain represents and transforms information -- with the challenges of a physical environment. Advances in cognitive robotics transfer to artificial intelligence, which seeks to develop more efficient computer systems patterned on the versatility of human thought.

Professor Bram Van Heuveln, who organized the lab, said cognitive scientists have developed a suite of elements -- perception/action, planning, reasoning, memory, decision-making -- that are believed to constitute human thought. When properly modeled and connected, those elements are capable of solving complex problems without the raw power required by precise mathematical computations.

"Suppose we wanted to build a robot to catch fly balls in an outfield. There are two approaches: one uses a lot of calculations -- Newton's law, mechanics, trigonometry, calculus -- to get the robot to be in the right spot at the right time," said Van Heuveln."But that's not the way humans do it. We just keep moving toward the ball. It's a very simple solution that doesn't involve a lot of computation but it gets the job done."

Robotics are an ideal testing ground for that principle because robots act in the real world, and a correct cognitive solution will withstand the unexpected variables presented by the real world.

"The physical world can help us to drive science because it's different from any simulated world we could come up with -- the camera shakes, the motors slip, there's friction, the light changes," Veksler said."This platform -- robotics -- allows us to see that you can't rely on calculations. You have to be adaptive."

The lab is open to all students at Rensselaer. In its first semester, the lab has largely attracted computer science and cognitive science students enrolled in a Cognitive Robotics course taught by Veksler, but Veksler and Van Heuveln hope it will attract more engineering and art students as word of the facility spreads.

"We want different students together in one space -- a place where we can bring the different disciplines and perspectives together," said Van Heuveln."I would like students to use this space for independent research: they come up with the research project, they say 'let's look at this.'"

The lab is equipped with five"Create" robots -- essentially a Roomba robotic vacuum cleaner paired with a laptop; three hand-eye systems; one Chiara (which looks like a large metal crab); and 10 LEGO robots paired with the Sony Handy Board robotic controller.

On a recent day, Jacqui Brunelli and Benno Lee were working on their robot"cat" and"mouse" pair, which try to chase and evade each other respectively; Shane Reilly was improving the computer"vision" of his robotic arm; and Ben Ball was programming his robot to maintain a fixed distance from a pink object waved in front of its"eye."

"The thing that I've learned is that the sensor data isn't exact -- what it 'sees' constantly changes by a few pixels -- and to try to go by that isn't going to work," said Ball, a junior and student of computer science and physics.

Ball said he is trying to pattern his robot on a more human approach.

"We don't just look at an object and walk toward it. We check our position, adjusting our course," Ball said."I need to devise an iterative approach where the robot looks at something, then moves, then looks again to check its results."

The work of the students, who program their robots with the Tekkotsu open-source software, could be applied in future projects, said Van Heuveln.

"As a cognitive scientist, I want this to be built on elements that are cognitively plausible and that are recyclable -- parts of cognition that I can apply to other solutions as well," said Van Heuveln."To me, that's a heck of a lot more interesting than the computational solution."

In a generic domain, their early investigations clearly show how a more cognitive approach employing limited resources can easily outpace more powerful computers using a brute force approach, said Veksler.

"We look to humans not just because we want to simulate what we do, which is an interesting problem in itself, but also because we're smart," said Veksler."Some of the things we have, like limited working memory -- which may seem like a bad thing -- are actually optimal for solving problems in our environment. If you remembered everything, how would you know what's important?"

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Doctor Who's Trusty Invention Is Anything but Sci-Fi: Sonic Screwdriver to Solve Future DIY Woes

Ultrasonic engineers at Bristol University and The Big Bang: UK Young Scientists and Engineers Fair (http://www.thebigbangfair.co.uk/) are uncovering how a real life version of the fictional screwdriver -- which uses sonic technology to open locks and undo screws -- could be created.

Professor of Ultrasonics, Bruce Drinkwater, who is working with The Big Bang to inspire young scientists of the future, says the answer lies in ultrasonic sound waves. By operating the waves at frequencies way beyond the realms of human hearing, they can be used to apply forces to objects.

The technology is already being trialled in modern manufacturing to fix parts together and ultrasonic force fields are being developed within the medical field to separate diseased cells from healthy cells. Professor Drinkwater and The Big Bang team are now exploring whether super powerful versions of these sound beams could bring Doctor Who's iconic device to life.

He says:"Doctor Who is renowned for bending the rules of science. But technology has radically moved on since the Doc first stepped out of his Tardis in the sixties. Whilst a fully functioning time machine may still be light years away, engineers are already experimenting with ultrasonic waves to move and manipulate small objects."

Engineers are looking into how ultrasonic waves can be spun at high speed to create a twisting force similar to that of a miniature tornado, which could undo screws remotely. They have also experimented with rotating ultrasonic force fields which would act like the head of a real screwdriver.

Doctor Who and DIY fans may still have to wait before they can add the sonic screwdriver to their Christmas wish lists. However, Professor Drinkwater hopes his work to make the impossible possible will inspire engineers, technologists and inventors of the future.

"Doctor Who's adventures have captured the imaginations of millions, young and old. And, however far fetched the Time Lord's encounters may seem, there are engineers and scientists out there who are using their skills to bring the magic to life.

"The sonic screwdriver may still be sometime in the making but ultrasonic technology is already making its mark in the medical and manufacturing arenas with some exciting results."

Professor Drinkwater has teamed up with The Big Bang, one of the UK's biggest celebrations of science and engineering, to inspire young people from all walks of life.

Taking place at ICC London ExCeL from 10 -- 12 March 2011, The Big Bang offers young people the chance to take part in a host of free interactive shows and workshops including Sky One's Brainiac Live! and BBC One's Bang Goes the Theory. It is also the ideal place to find out about the exciting career options available in science and engineering. The Big Bang hosts the finals of the prestigious National Science& Engineering Competition and also kicks off National Science& Engineering Week 2011.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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Color-Changing 'Blast Badge' Detects Exposure to Explosive Shock Waves

The findings are described in the ahead-of-print online issue ofNeuroImage.

"We wanted to create a 'blast badge' that would be lightweight, durable, power-free, and perhaps most important, could be easily interpreted, even on the battlefield," says senior author Douglas H. Smith, MD, director of the Center for Brain Injury and Repair and professor of Neurosurgery at Penn."Similar to how an opera singer can shatter glass crystal, we chose color-changing crystals that could be designed to break apart when exposed to a blast shockwave, causing a substantial color change."

D. Kacy Cullen, PhD, assistant professor of Neurosurgery, and Shu Yang, PhD, associate professor of Materials Science and Engineering, were co-authors with Smith.

Blast-induced traumatic brain injury is the"signature wound" of the current wars in Iraq and Afghanistan. However, with no objective information of relative blast exposure, soldiers with brain injury may not receive appropriate medical care and are at risk of being returned to the battlefield too soon.

"Diagnosis of mild traumatic brain injury {TBI} is challenging under most circumstances, as subtle or slowly progressive damage to brain tissue occurs in a manner undetectable by conventional imaging techniques," notes Cullen. There is also a debate as to whether mild TBI is confused with post-traumatic stress syndrome."This emphasizes the need for an objective measure of blast exposure to ensure solders receive proper care," he says.

Sculpted by Lasers

The badges are comprised of nanoscale structures, in this case pores and columns, whose make-up preferentially reflects certain wavelengths. Lasers sculpt these tiny shapes into a plastic sheet.

Yang's group pioneered this microfabrication of three-dimensional photonic structures using holographic lithography."We came up the idea of using three-dimensional photonic crystals as a blast injury dosimeter because of their unique structure-dependent mechanical response and colorful display," she explains. Her lab made the materials and characterized the structures before and after the blast to understand the color-change mechanism.

"It looks like layers of Swiss cheese with columns in between," explains Smith. Although very stable in the presence of heat, cold or physical impact, the nanostructures are selectively altered by blast exposure. The shockwave causes the columns to collapse and the pores to grow larger, thereby changing the material's reflective properties and outward color. The material is designed so that the extent of the color change corresponds with blast intensity.

The blast-sensitive material is added as a thin film on small round badges the size of fill-in-the-blank circles on a multiple-choice test that could be sewn onto a soldier's uniform.

In addition to use as a blast sensor for brain injury, other applications include testing blast protection of structures, vehicles and equipment for military and civilian use.

This research was funded by the Philadelphia Institute of Nanotechnology, and supported in part by the Office of Naval Research and the Air Force Office of Scientific Research.

Disclaimer: This article is not intended to provide medical advice, diagnosis or treatment. Views expressed here do not necessarily reflect those of ScienceDaily or its staff.

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High Performance Infrared Camera Based on Type-II InAs/GaSb Superlattices Created

Created by Manijeh Razeghi, Walter P. Murphy Professor of Electrical Engineering and Computer Science, and researchers in the Center for Quantum Devices in the McCormick School of Engineering and Applied Science, the long wavelength infrared focal plane array camera provides a 16-fold increase in the number of pixels in the image and can provide infrared images in the dark.

Their results were recently published in the journalApplied Physics Letters.

The goal of the research is to offer a better alternative to existing long wavelength infrared radiation (LWIR) cameras, which, with their thermal imaging capabilities, are used in everything from electrical inspections to security and nighttime surveillance. Current LWIR cameras are based on mercury cadmium telluride (MCT) materials, but the Type-II superlattice is mercury-free, more robust, and can be deposited with better uniformity. This will significantly increase yield and reduce camera cost once the technology goes commercial.

"Not only does it prove Type-II superlattices as a viable alternative to MCT, but also it widens the field of applications for infrared cameras," Razeghi said."The importance of this work is similar to that of the realization of mega-pixel visible cameras in the last decade, which shaped the world's favor for digital cameras."

Type-II InAs/GaSb superlattices were first invented by Nobel laureate Leo Esaki in the 1970s, but it has taken time for the material to mature. The LWIR detection mechanism relies on quantum size effects in a completely artificial layer sequence to tune the wavelength sensitivity and demonstrate high efficiency. Razeghi's group has been instrumental in pioneering the recent development of Type-II superlattices, having demonstrated the world's first Type-II-based 256×256 infrared camera just a few years ago.

"Type-II is a very interesting and promising new material for infrared detection," Razeghi said."Everything is there to support its future: the beautiful physics, the practicality of experimental realization of the material. It has just taken time to prove itself, but now, the time has come."

Tremendous obstacles, especially in the fabrication process, had to be overcome to ensure that the 1024×1024 Type-II superlattice-based camera would have equivalent performance as the previously realized 320×256 cameras. Operating at 81 K, the new camera can collect 78 percent of the light and is capable of showing temperature differences as small as 0.02° C.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

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