|  Author | Topic: New Millenium Technology IV (Read 14,769 times) |
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|  | Re: New Millenium Technology IV
« Reply #285 on Oct 4, 2008, 11:16am » | |
See What I See – Machines With Mental Muscle
ScienceDaily (Oct. 3, 2008) — The way we use and interact with machines is undergoing a profound change as computers are programmed to learn from experience and see more how we see. European research into machine learning is pushing back the boundaries of computer capabilities.
Computers do not see things the way we do. Sure, they can manipulate recorded images, for example, but they currently understand very little about what is inside these pictures or videos. All the interpretation work must be done by humans, and that is expensive. But one European project is making computers more similar to us in their ability to interpret images and their surrounds.
Individuals from all walks of life, as well as sectors such as industry, services and education, stand to reap immense benefits from semi-autonomous, more intuitive machines that are able to do things which were, until now, either not possible, super expensive or the preserve of humans.
This has been made possible thanks to the developments in, and convergence of, methods for creating, obtaining and interpreting metadata – at its simplest level this is data about data, or facts about facts – in complex multimedia environments.
MUSCLE, an EU-funded super project which created a pan-European network of excellence involving more than 30 academic and research institutions from 14 countries, has come up not only with new paradigms but a range of practical applications.
Vast scale
The scale of the project was so vast, a special section to showcase its achievements has been set up in the 3D Second Life internet virtual world, which has millions of denizens.
The Virtual MUSCLE experience inside Second Life has been created as a one-stop information centre to ensure the continuation and sustainability of the project’s achievements. Users are impersonated as avatars (computer representations of themselves) enabling them to experience multimedia content by literally walking through it. They are able to hold real-time conversations with other members of the community, exchange experiences, or just simply browse.
After an initial two years of collaborative research across the MUSCLE network, a series of showcases were established with several institutions working together on each one to produce practical applications.
Virtual tongue twister
One of these is an articulatory talking head, developed to help people who have difficulties in pronouncing words and learning vocabulary. This ‘insightful’ head models what is happening inside the human mouth, including where the tongue is positioned to make particular sounds, so the users can copy what they see on screen.
A second showcase functions as a support system for complex assembly tasks, employing a user-friendly multi-modal interface. By augmenting the written assembly instructions with audio and visual prompts much more in line with how humans communicate, the system allows users to easily assemble complex devices without having to continually refer to a written instruction manual.
In another showcase, researchers have developed multi-modal Audio-Visual Automatic Speech Recognition software which takes its cues from human speech patterns and facial structures to provide more reliable results than using audio or visual techniques in isolation.
Similarly, a showcase which has already attracted a lot of publicity, especially in the USA, is one that analyses human emotion using both audio and visual clues.
“It was trialled on US election candidates to see if their emotional states actually matched what they were saying and doing, and it was even tried out, visually only of course, on the enigmatic Mona Lisa,” says MUSCLE project coordinator Nozha Boujemaa.
Horse or strawberry?
Giving computers a better idea of what they are seeing or what the inputs mean, another showcase developed a web-based, real-time object categorisation system able to perform searches based on image recognition - photos including horses, say, or strawberries! It can also automatically categorise and index images based on the objects they contain.
In an application with anti-piracy potential, one showcase came up with copy detection software. “This is an intelligent video method of detecting and preventing piracy. There is a lot of controversy at the moment about copyright film clips being posted on YouTube and other websites. This software is able to detect copies by spotting any variation from original recordings,” Boujemaa explains.
“Another application is for broadcasters to be able to detect if video from their archives is being used without royalties been paid or acknowledgement of the source being made.
Europe’s largest video archive, the French National Audiovisual Archive, has now been able to ascertain that broadcasters are only declaring 70% of the material they are using,” she tells ICT Results.
Other types of recognition software, effectively helping computers see what we see, can remotely monitor, detect and raise the alarm in a variety of scenarios from forest fires to old or sick people living alone falling over. The latter falls under the heading of “unusual behaviour” which also has applications in video security monitoring with “intelligent” cameras able to alert people in real time if they think somebody is suspicious.
“During the course of the project, we produced more than 600 papers for the scientific community, as well as having two books published, one on audiovisual learning techniques for multimedia and the other on the importance of using multimedia rather than just monomedia,” she says.
Although the massive project has now wound down, its legacy remains online, in print and most of all in a host of new applications that will affect the lives of people all over the world.
http://www.sciencedaily.com/releases/2008/10/081003123246.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #286 on Oct 4, 2008, 11:19am » | |
Step Right Up, Let The Computer Look At Your Face And Tell You Your Age
![[image]](http://img524.imageshack.us/img524/4751/080923121949large709732so5.jpg "[image]")
In addition to performing tasks such as security control and surveillance monitoring, age-estimation software also could be used for electronic customer relationship management or to target specific audiences with advertising, said Thomas S. Huang, the William L. Everitt Distinguished Professor of Electrical and Computer Engineering at the U. of I. (Credit: Photo by L. Brian Stauffer)
ScienceDaily (Oct. 3, 2008) — People who hope to keep their age a secret won't want to go near a computer running this software.
Like an age-guesser at a carnival, computer software being developed at the University of Illinois can fairly accurately estimate a person's age. But, unlike age-guessers, who can view a person's body, the software works by examining only the person's face.
"Age-estimation software is useful in applications where you don't need to specifically identify someone, such as a government employee, but would like to know their age," said Thomas S. Huang, the William L. Everitt Distinguished Professor of Electrical and Computer Engineering at the U. of I.
For example, age-recognition algorithms could stop underage drinkers from entering bars, prevent minors from purchasing tobacco products from vending machines, and deny children access to adult Web sites, said Huang, who leads the Image Formation and Processing group at the university's Beckman Institute.
Estimating someone's age is not an easy task, even for a computer. That's partly because the aging process is determined not only by a person's genetic makeup, but by many other factors as well, including health, location and living conditions.
"Human faces do convey a significant amount of information, however, and provide important visual cues for estimating age," Huang said. "Facial attributes, such as expression, gender and ethnic origin, play a crucial role in our image analysis."
Consisting of three modules – face detection, discriminative manifold learning, and multiple linear regression – the researchers' age-estimation software was trained on a database containing photos of 1,600 faces.
The software can estimate ages from 1 year to 93 years. The software's accuracy ranges from about 50 percent when estimating ages to within 5 years, to more than 80 percent when estimating ages to within 10 years. The accuracy can be improved by additional training on larger databases of faces, Huang said.
In addition to performing tasks such as security control and surveillance monitoring, age-estimation software also could be used for electronic customer relationship management.
For example, a camera snapping photos of customers could collect demographic data – such as how many adult men and women buy burgers, or what percentage of teenagers purchase a particular soft drink.
Or, combined with algorithms that identify a person's sex, age-estimation software could help target specific audiences for specific advertisements. For example, a store display might advertise a new automobile or boat as a man walks by, or new clothing or cosmetics as a woman walks by.
"All of this can be done without violating anyone's privacy," Huang said. "Our software does not identify specific individuals. It just estimates their ages."
Huang is affiliated with the university's Center for Advanced Study, Coordinated Science Laboratory, Information Trust Institute, and department of computer science.
Funding was provided by the National Science Foundation and the Intelligence Advanced Research Projects Activity. The researchers published their findings in the two journals IEEE Transactions on Multimedia and IEEE Transactions on Image Processing in 2008.
http://www.sciencedaily.com/releases/2008/09/080923121949.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #287 on Oct 4, 2008, 11:20am » | |
Tweezers Trap Nanotubes By Color
ScienceDaily (Sep. 29, 2008) — Singled-walled carbon nanotubes are graphene sheets wrapped into tubes, and are typically made up of various sizes and with different amounts of twist (also known as chiralities). Each type of nanotube has its own electronic and optical properties.
Physicists at Osaka University in Japan used colored light to selectively manipulate different types of carbon nanotubes. They found that some of nanotubes displayed a tendency to cluster at the focal area of a focused laser beam.
Nanotubes are known for their strong color-dependant interactions with light. By using an optical tweezer, a device that traps microscopic or nanoscopic objects in laser beams, researchers were able to selectively pull only specific colors of nanotube into focus.
Their results are the first experimental evidence demonstrating that colored light drives the clustering of nanotubes in a laser tweezer. Moreover, this color dependence can be exploited to select one type of nanotube over another. The study is a significant step towards developing optical methods for sorting and purification of nanotubes, a process that remains a major challenge for the application of nanotubes to engineering.
Journal reference:
1. Thomas Rodgers, Satoru Shoji, Zouheir Sekkat, and Satoshi Kawata. Selective Aggregation of Single-Walled Carbon Nanotubes Using the Large Optical Field Gradient of a Focused Laser Beam. Physical Review Letters, 2008; 101 (12): 127402 DOI: 10.1103/PhysRevLett.101.127402
http://www.sciencedaily.com/releases/2008/09/080926184949.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
|
Big Bunny
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| | Re: New Millenium Technology IV
« Reply #288 on Oct 4, 2008, 11:23am » | |
Micro Honeycomb Materials Enable New Physics In Aicraft Sound Reduction
![[image]](http://img243.imageshack.us/img243/2021/080929163717large727082zj8.jpg "[image]")
Georgia Tech Research Institute research engineer Jason Nadler has developed a new microchanneled material that reduces aircraft engine noise by wearing it down through a process called viscous shear. (Credit: Georgia Tech Photo: Gary Meek)
ScienceDaily (Sep. 30, 2008) — Noise from commercial and military jet aircraft causes environmental problems for communities near airports, obliging airplanes to follow often complex noise-abatement procedures on takeoff and landing. It can also make aircraft interiors excessively loud.
To address this situation, engineers at the Georgia Tech Research Institute (GTRI) are turning to innovative materials that make possible a new approach to the physics of noise reduction. They have found that honeycomb-like structures composed of many tiny tubes or channels can reduce sound more effectively than conventional methods.
"This approach dissipates acoustic waves by essentially wearing them out," said Jason Nadler, a GTRI research engineer. "It's a phenomenological shift, fundamentally different from traditional techniques that absorb sound using a more frequency-dependent resonance."
The two-year project is sponsored by EADS North America, the U.S. operating entity of EADS.
Most sound-deadening materials – such as foams or other cellular materials comprising many small cavities – exploit the fact that acoustic waves resonate through the air on various frequencies, Nadler explains.
Just as air blowing into a bottle produces resonance at a particular tone, an acoustic wave hitting a cellular surface will resonate in certain-size cavities, thereby dissipating its energy. An automobile muffler, for example, uses a resonance-dependent technique to reduce exhaust noise.
The drawback with these traditional noise-reduction approaches is that they only work with some frequencies – those that can find cavities or other structures in which to resonate.
Nadler's research involves broadband acoustic absorption, a method of reducing sound that doesn't depend on frequencies or resonance. In this approach, tiny parallel tubes in porous media such as metal or ceramics create a honeycomb-like structure that traps sound regardless of frequency. Instead of resonating, sound waves plunge into the channels and dissipate through a process called viscous shear.
Viscous shear involves the interaction of a solid with a gas or other fluid. In this case, a gas – sound waves composed of compressed air – contacts a solid, the porous medium, and is weakened by the resulting friction.
"It's the equivalent of propelling a little metal sphere down a rubber hose when the sphere is just a hair bigger than the rubber hose," Nadler explained. "Eventually the friction and the compressive stresses of contact with the tube would stop the sphere."
This technique, Nadler adds, is derived from classical mechanical principles governing how porous media interact with gases – such as the air through which sound waves move. Noise abatement using micro-scale honeycomb structures represents a new application of these principles.
"You need to have the hole big enough to let the sound waves in, but you also need enough surface area inside to shear against the wave," he said. "The result is acoustic waves don't resonate; they just dissipate."
In researching this approach, Nadler constructed an early prototype from off-the-shelf capillary tubes, which readily formed a low-density, honeycomb-like structure. Further research showed that the ideal material for broadband acoustic absorption would require micron-scale diameter tubes and a much lower structural density.
Creating such low-density structures presents an interesting challenge, Nadler says. It requires a material that's light, strong enough to enable the walls between the tubes to be very thin, and yet robust enough to function reliably amid the high-temperature, aggressive environments inside aircraft engines.
Among the likely candidates are superalloys, materials that employ unusual blends of metals to achieve desired qualities such as extreme strength, tolerance of high temperatures and corrosion resistance.
Nadler has developed what could be the world's first superalloy micro honeycomb using a nickel-base superalloy. At around 30 percent density, the material is very light – a clear advantage for airborne applications – and also very strong and heat resistant.
He estimates this new approach could attenuate aircraft engine noise by up to 30 percent. Micro-honeycomb material could also provide another means to protect the aircraft in critical areas prone to impact from birds or other foreign objects by dissipating the energy of the collision.
http://www.sciencedaily.com/releases/2008/09/080929163717.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #289 on Oct 4, 2008, 11:32am » | |
Method Of Predicting Clear Air Turbulence Could Make Flights Smoother In The Future
![[image]](http://img376.imageshack.us/img376/3883/081001093239large775536fy7.jpg "[image]")
A new forecasting method could help pilots chart new courses around patches of rough but clear air that can turn an otherwise unremarkable flight into a nightmare. (Credit: iStockphoto/David Joyner)
ScienceDaily (Oct. 1, 2008) — It comes blasting out of the blue on your airplane flight: sudden bumpiness and sometimes even a violent plummeting. It arrives without warning, and it can be more than frightening, since it causes tens of millions of dollars in injury claims every year.
It's called clear air turbulence (CAT), and a new forecasting method, published in the Journal of Atmospheric Sciences and led by a researcher at the University of Georgia, could help pilots chart new courses around these patches of rough but clear air that can turn an otherwise unremarkable flight into a nightmare.
"Our new method allows superior forecasts for CAT beyond the tools that have been in use," said John Knox, an assistant professor in the department of geography in UGA's Franklin College of Arts and Sciences. "Commercial aircraft encounter severe-or-greater turbulence about 5,000 times each year, and the majority of these occur 10,000 feet above the Earth's surface. This new method gives pilots a way to avoid turbulence that's not associated with nearby thunderstorms or significant cloudiness."
Other authors on the paper include Donald McCann of McCann Aviation Weather Research, Inc., of Overland Park, Kan., and Paul Williams of the department of meteorology at the University of Reading in Great Britain.
The new method predicts energy associated with gravity waves—phenomena in the atmosphere that look like ocean waves but which can occur in clear air. They can be created by air flow over mountains, frontal boundaries or other causes. The type of gravity wave that Knox and his colleagues identified as a possible source of bumpiness comes from a different source. These waves are spontaneously generated and associated with jet streams at high altitudes, near cruising levels for airplanes.
When a plane flies through them, the sensation is like being in a small boat on a stormy sea. But where a boat's skipper can see rough sea, gravity waves in the air are usually invisible, and pilots often don't know they're present until they're flying right into them.
Predicting turbulence caused by nearby storms or low pressure systems is much easier than knowing when CAT might hit, said Knox. Still, several hundred significant injuries occur in the U.S. because of clear air turbulence, and because it occurs in the absence of obvious weather, wary passengers tend to wonder if they are in danger.
There are predictive models in use now, and an improved version of the Graphical Turbulence Guidance (GTG) algorithm, currently the best CAT forecasting method, will soon be online for airline pilots, said Knox. But he noted that even the GTG doesn't have some of the desirable features of the method just published in the Journal of Atmospheric Sciences.
The new method is based on something called the Lighthill-Ford theory of spontaneous imbalance, developed by a British theoretician in the early 1990s. Knox and his colleagues spent several years turning this theory into a forecast tool.
The team first simplified the theory then developed an algorithm to use the theory to make predictions of turbulence. The algorithm was next tested on five months' worth of high-resolution weather forecast model output from 2005-2006. The researchers then compared the algorithm's prediction of turbulence to actual pilot observations of it. The results of this statistical analysis demonstrated that the team's method performed better than the best methods of CAT forecasting available during that period, said Knox.
"Essentially what we have is a mathematical model that translates the theory into numbers that describe the gravity waves," said Knox. "These numbers can then drive an algorithm that gives you a forecast of the kinetic energy associated with turbulence."
The researchers hypothesize that a clear sequence of events occurs to create CAT and understanding that sequence is crucial to predicting the location of the turbulence.
"Gravity waves act upon the environment and then destabilize it," said Knox. "Even weak gravity waves may initiate turbulence."
One problem with current CAT-forecasting models is that they are "at least partly empirical," said Knox. "Current methods often rely on rules-of-thumb based on pilot experience that aren't always grounded in rigorous theory." The new method is based "on a single, consistent theory of spontaneous imbalance," and thus should at least theoretically be more reliable, Knox said.
He added that adoption of the new method could potentially create "major improvements in CAT forecasting." Thousands of passengers who are fearful of "things that go bump in the flight" hope he's correct.
http://www.sciencedaily.com/releases/2008/10/081001093239.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #290 on Oct 4, 2008, 11:33am » | |
Smart Electricity Meter Developed
ScienceDaily (Oct. 1, 2008) — The Power Electronics team from Swansea University’s School of Engineering has developed one of the world’s most advanced Smart Electricity Meters. And the team is now supplying nearly 1.5MWh per year of free ‘Green electricity’ to the University, helping to reduce its carbon footprint.
The team, based within the Electronic Systems Design Centre, implemented their prototype Smart Meter to highlight the potential of electricity metering technologies in the near future.
The Smart Meter is to be the focal point for a consumer’s personal energy queries. It monitors their energy consumption, giving information not just through a traditional power reading, but in a user-friendly way by displaying animated graphics of money on a large clear screen on the meter.
It also goes one step further than most other potential Smart Meters in that it monitors individual power circuits in the home, including upstairs lighting, downstairs lighting and kitchen sockets.
The team believes there is also the possibility to monitor individual appliances when the technology is adopted further.
The presentation of consumption information is complemented by the ability to show power generated from micro-renewable technologies in a ‘plug and play’ manner, similar to the wind turbine currently commercially available, and generic solar panels.
This is an effort to provide a simple, easy to set up method for people with no expertise in Power Electronics.
The Smart Meter is linked to a number of solar panels on the roof of the University’s Engineering building through a power converter.
The power delivered from the solar panels is monitored within the meter to allow the ‘Green energy’ produced to be reviewed in an easy to understand way.
This allows clear indications whether the renewable technology has been a beneficial purchase and the likely financial performance from the initial investment.
The meter also has communication abilities, allowing the readings of power consumption and generation to be instantly available to the supplier and to the consumer via web pages, wireless in-home displays, or potentially even a television channel.
Richard Lewis, a leading researcher on the Swansea Smart Meter team, said: “The time for complacency is over! Swansea University, through its team and initiatives, is leading the effort in making energy awareness a top priority and is working to provide the tools to do it.
“We are currently looking to create a fully functional prototype from the current demonstration unit and plan to begin residential trials within the next 18 months.”
Interest in Smart Metering technologies has been sparked by a number of television commercials highlighting the availability of Smart Meters to business, but the residential sector still has some way to go.
Small scale trials are still underway and the adoption of Smart Metering in the residential sector could be a few years away.
The Swansea team are looking to be the UK pioneers, by offering metering technologies to those who wish to be early adopters.
Dr Petar Igic, who is leading the Energy and Power Electronics research within the University’s School of Engineering, said: “The project is one of a number of Welsh Assembly Government Knowledge Exploitation Fund research projects being undertaken in Wales and facilitated by the Welsh Energy Research Centre (WERC) to ensure Wales is at the forefront of current energy technologies.
“Smart Electricity Metering is a key part of the Energy Efficiency research theme, since making more efficient and more responsible use of the electric power generated is as important as finding renewable energy sources.”
http://www.sciencedaily.com/releases/2008/10/081001130044.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #291 on Oct 4, 2008, 11:34am » | |
Zooming Way In, Technique Offers Close-ups Of Electrons, Nuclei
ScienceDaily (Oct. 1, 2008) — Providing a glimpse into the infinitesimal, physicists have found a novel way of spying on some of the universe's tiniest building blocks.
Their "camera," described this week in the journal Nature, consists of a special "flaw" in diamonds that can be manipulated into sensitively monitoring magnetic signals from individual electrons and atomic nuclei placed nearby.
The new work represents a dramatic sharpening of the basic approach used in nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI), which ascertain chemical structures and image inside human bodies by scanning the magnetic activity of billions of individual nuclei. The new diamond-based magnetic sensor could enable novel forms of imaging, marrying NMR's noninvasive nature with atomic-scale spatial resolution, potentially benefiting fields ranging from materials science, spintronics, and quantum information to structural biology, neuroscience, and biomedicine.
Among other applications, the new research could make it possible to peer inside proteins, map the structure of impossibly intricate molecules, closely observe the dynamics of microscopic biochemical processes, monitor the activity of neural circuits, or use single electrons and nuclei for storing and processing information. Some of these applications were recently described by the authors in a separate contribution published online Sept. 14 in the journal Nature Physics.
"Although some existing magnetic field sensors have higher sensitivity, they probe magnetic fields over large volumes of space," says Mikhail D. Lukin, professor of physics in Harvard University's Faculty of Arts and Sciences. "The combination of excellent sensitivity and nanoscale spatial resolution that we demonstrate is completely unique. Potentially, it may allow one to image single nuclei in individual molecules."
The collaborative research, led by Lukin and Harvard physicists Amir Yacoby and Ronald L. Walsworth, involved scientists from Harvard, the Smithsonian Institution, the Massachusetts Institute of Technology, and the University of Pittsburgh.
The work builds on a Science paper published last year by Lukin and colleagues. That paper reported that single atoms of carbon-13 -- which make up some 1.1 percent of natural diamond -- can be manipulated via a nearby single electron that can, in turn, be controlled by focusing laser light on a diamond lattice flaw where nitrogen replaces an atom of carbon. Such excitation using optical and microwave radiation causes the diamond flaw's electron spin to act as a very sensitive magnetic probe with extraordinary spatial resolution.
An electron's spin, or intrinsic angular momentum, acts like a tiny magnet, providing one of the few outwardly detectable signs of an atom's location. An atomic nucleus can also have a spin, but because a nucleus is much heavier than an electron, its magnetic field is a thousand times smaller, making it much harder to detect.
"Our magnetic sensor is based on a single electronic spin associated with an impurity or flaw in a small diamond crystal. We managed to turn our understanding of quantum information physics into an extraordinary measuring apparatus," says Yacoby, professor of physics at Harvard. "A nanocrystal of diamond containing this specific type of impurity could be placed on the tip of a needle as a minuscule probe of extremely weak magnetic fields, such as those generated by the spin of an electron or even an atomic nucleus."
The 2007 work effectively brought the futuristic technology of quantum information systems into the realm of solid-state materials under ordinary conditions; the current research builds on that advance to develop new nanometer-scale magnetic sensors that could have important new implications in imaging of a variety of materials, biological compounds, and tissues.
"Precision sensing of magnetic fields is at the forefront of a wide range of scientific fields -- from nanoscience to bioimaging," says Walsworth, senior lecturer on physics at Harvard and senior physicist at the Smithsonian. "Potential nanoscale applications of the diamond magnetic sensor include detection of individual electron and nuclear spins in complex biological molecules, and serving as a universal 'quantum magnetic head' for addressing and readout of quantum bits of information encoded in an electron or nuclear spin memory."
Accompanying this work in the current issue of Nature is a report from scientists at the University of Stuttgart who've obtained the first scanning images using a diamond magnetic sensor.
"This is a case where the sum of two contributions is really greater than their parts," says Lukin. "Together, they really jump-start a new research field."
Lukin, Yacoby, and Walsworth's co-authors on the Nature paper are Jeronimo Maze, Sungkun Hong, Liang Jiang, Emre Togan, and Alexander Zibrov, all at Harvard; Paul Stanwix of the Smithsonian; Jonathan Hodges at Harvard and MIT; Jacob Taylor at MIT; and M.V. Gurudev Dutt at Pittsburgh. The work was supported by the National Science Foundation, the Defense Advanced Research Projects Agency, the Packard Foundation, and Harvard's Center for Nanoscale Systems.
http://www.sciencedaily.com/releases/2008/10/081001145014.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #292 on Oct 4, 2008, 11:41am » | |
Flexi Display Technology Is Now
![[image]](http://img162.imageshack.us/img162/8008/0810020842178333737zo9.jpg "[image]")
Flexi display technology. (Credit: Image courtesy of Institute of Physics)
ScienceDaily (Oct. 2, 2008) — Rigid television screens, bulky laptops and still image posters are to be a thing of the past as new research, published in the New Journal of Physics, heralds the beginning of a technological revolution for screen displays.
Screen display technology is taking a significant step forward as researchers from Sony and the Max Planck Institute demonstrate the possibility of bendable optically assessed organic light emitting displays for the first time, based on red or IR-A light upconversion.
The paper, 'Annihilation Assisted Upconversion: All-Organic, Flexible and Transparent Multicolour Display', makes feasible the design of computers that can be folded up and put in your pocket, the mass-production of moving image posters for display advertising, televisions which can be bended to view or, even, newspaper display technology which allows readers to upload daily news to an easy-to-carry display contraption.
* All organic, upconversion multicolour displays have significant advantages when compared to the traditional technology used for projection displays and televisions. Namely UC displays are:
* All-organic − transparent and flexible
* Ultra low excitation intensity (red or IR)– less than 15 mWcm-2
* Emissive display – no speckles
* Coherent or non-coherent excitation allowed
* High efficiency – at the moment ca. 6 %
* Fast response times – ca. 1 µs up to 500 µs on request (LCDs have ms)
* Almost unlimited viewing angle – up to the total internal reflection angle
* Tailoring of emitted colours realised even when using the same excitation source
* Multilayer Displays
* Size limited only by the size of the substrates
With LCD-based projection displays, the liquid crystal acts as a filter for the light being shone through so when coherent excitation is used (e.g. laser diodes) the problems with speckles are serious. For this organic emissive UC displays, the organic molecules themselves emit non-coherent light in 4 (all directions) to produce an image.
Sony announced the development of flexible OLED display screens in 2006 but glitches such as size and resolution limitations, and the difficulty of structuring the organic compounds so as not to be distorted when bent, have stopped designs coming to market. This new technology for optically excited organic emissive displays hasn't got this problem and gives further opportunities for new applications.
The research published today concludes through the use of a new structure and unique combinations for the organic compounds within viscous polymeric matrix, that there need be no size or resolution limitations for the new screens.
The researchers conclude, "To the best of our knowledge we demonstrate for the first time a versatile colour all-organic and transparent UC-display. The reported displays are also flexible and have excellent brightness."
http://www.sciencedaily.com/releases/2008/10/081002084217.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
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"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #293 on Oct 4, 2008, 11:43am » | |
Immune System For Electronics? Electronics That Can Diagnose And Heal Themselves Under Development
ScienceDaily (Oct. 2, 2008) — Researchers at the University of the West of England (UWE) are to carry out ground breaking research with collaborators from the University of York* into creating electronic systems that can diagnose and heal their own faults in ways similar to the human immune system.
The project is called SABRE (Self-healing cellular Architectures for Biologically-inspired highly Reliable Electronic systems). The part of the project to be carried out in Bristol will be based at Bristol Robotics lab (BRL), which is jointly run by the University of Bristol and UWE.
Increasingly, our lives are intertwined with digital electronic equipment. From gadgets to household appliances, computers, and the life-saving systems which ensure that cars and planes are safe, these devices can be extremely complex and often have hundreds of thousands of components on a single chip. However, if one component fails this commonly causes catastrophic failure of the whole system.
Electronic hardware designers have achieved fantastic levels of reliability so far but, as such devices become more and more complex, such instances can only become more common. Under fault conditions it would, therefore, be highly desirable for the system to be able to cope with faults, and continue to operate effectively even if one or more components have failed; but this is not the way electronic systems are currently designed.
Drawing on inspiration from nature, the researchers at York and Bristol will look for ways to create electronic systems based on a structure of ‘cells’ which have the ability to work together to defend system integrity, diagnose faults, and heal themselves. The researchers will be looking at the way complex biological systems, such as the defence mechanism of the human body, are able to deal with faults and still keep functioning.
Dr. Tony Pipe, (Bristol Robotics Laboratory) explains, “When an electronic system malfunctions it should be able to cope with minor faults and continue to operate effectively even if one or more components fail. Currently, those few electronic systems that are designed to be fault-tolerant either replicate whole sub-systems at a high level in the overall architecture (similar to having two lungs), or roll back to a simpler, safer mode when there is a malfunction, but still replicate the whole system or a large part of it in a simplified form. This is a vital function in current safety-critical systems such as anti-lock breaking, fly-by-wire aircraft, space exploration, as well as industrial control and shutdown systems.
“However highly complex living organisms such as the human body are able to deal with malfunctions at a much lower level, that of the cells, defending the system overall by repairing damage to cells, thus maintaining normal functionality. The human body is both reliable and highly complex. It is this ability that we want to try to replicate in electronic systems. By studying the multi-cellular structure of living organisms and their protective immune systems, we hope to be able to design ‘nature-like’ fault tolerant architectures for electronics. This research has the potential to influence the way complex electronic systems are designed in the future, creating a new generation of electronic systems which are fault tolerant and self healing.”
The research will pave the way for a biologically inspired unique design approach for electronic systems across a wide range of applications, from communication through computing and control, to systems operating in safety-critical or hostile environments.
The project is funded by EPSRC.
http://www.sciencedaily.com/releases/2008/10/081002095018.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #294 on Oct 4, 2008, 11:55am » | |
Under Pressure At The Nanoscale, Polymers Play By Different Rules
ScienceDaily (Oct. 2, 2008) — Scientists putting the squeeze on thin films of polystyrene have discovered that at very short length scales the polymer doesn't play by the rules.
From buttons to storage bins, the molding of polymers is big business. At the nanoscale, processes such as nanoimprint lithography squeeze polymers to form patterns during the manufacture of semiconductor devices, organic electronics and optics. Thin films of polymer are important in adhesives, coatings and lubricants.
"Although applications for nanoscale polymer flow are being widely investigated, the underlying, fundamental polymer physics is not," said William P. King, a Kritzer Faculty Scholar and professor of mechanical engineering at the University of Illinois.
"Understanding the way a polymer flows during nanoscale molding or imprinting processes is essential for designing new, nanoscale manufacturing processes," said King, who also is a researcher at the university's Beckman Institute.
In a paper to be published Thursday (Oct. 2), by Science Express, the online version of the journal Science, King and collaborators at the U. of I. and Trinity College, Dublin, report polymer squeeze flow measurements made at unprecedented, short length scales.
"We found an unexpected increase in the squeeze flow of thin films when the film thickness was smaller than 100 nanometers," King said. "This seemed backwards. Normally, you would expect the polymer to become harder and harder to press into thinner films."
The effect was even more pronounced in polymers of higher molecular weight, King said. "We expected the viscosity to increase with increasing molecular weight, but we found the opposite to be true when the films were thin enough."
Film thickness and molecular entanglement was the key, King said. In thick films, polymer chains are tangled together like cooked spaghetti. However, when the polymer film starts with a smaller initial thickness, a point is reached where the polymer chains change the way they interact with their neighbors. In very thin films, the polymer chains can no longer intertwine, and become like isolated blobs. This change in entanglement decreases the viscosity and increases the lateral squeeze flow.
To make the measurements, the researchers used a modified nanoscale indentation technique, which pressed a flat "punch" into very thin films of polystyrene. The punch, which was much wider than the thickness of the film, forced the polymer to flow around it. This lateral squeeze flow governs the dynamics of polymer movement during processes such as nanoimprint nanomanufacturing.
The research is a significant step forward in the understanding of polymer deformation that is directly related to nanoscale manufacturing, King said. "Our results suggest that polymer flow during nanoscale manufacturing may be enhanced by selecting polymers of higher molecular weight."
With King, co-authors of the paper are former U. of I. postdoctoral researcher Harry Rowland, and physics professor John Pethica and physics lecturer Graham Cross, both at Trinity College.
The work was funded by the Science Foundation of Ireland, the U.S. Department of Energy, and the U.S. National Science Foundation through the U. of I.'s Center for Nanoscale Chemical-Electrical-Mechanical Manufacturing Systems.
http://www.sciencedaily.com/releases/2008/10/081002172011.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #295 on Oct 4, 2008, 11:56am » | |
Scientists Explore Putting Electric Cars On A Two-way Power Street
ScienceDaily (Oct. 2, 2008) — Think of it as the end of cars’ slacker days: No more sitting idle for hours in parking lots or garages racking up payments, but instead earning their keep by providing power to the electricity grid.
Scientists at the University of Michigan, using a $2 million grant from the National Science Foundation (NSF), are exploring plug-in hybrid electric vehicles (PHEV) that not only use grid electricity to meet their power needs, but return it to the grid, earning money for the owner.
“Cars sit most of the time,” said Jeff Stein, a professor in the Department of Mechanical Engineering. “What if it could work for you while it sits there? If you could use a car for something more than just getting to work or going on a family vacation, it would be a whole different way to think about a vehicle, and a whole different way to think about the power grid, too.”
The concept, called vehicle-to-grid (V2G) integration, is part of a larger effort to embrace large-scale changes that are needed to improve the sustainability and resilience of the transportation and electric power infrastructures. If V2G integration succeeds, it will enable the grid to utilize PHEV batteries for storing excess renewable energy from wind and the sun, releasing this energy to grid customers when needed, such as during peak hours.
This will lead to more sustainable transportation and grid infrastructures, and will also increase the resilience of these infrastructures to sharp changes in energy costs, supply, or demand.
The NSF’s Emerging Frontiers in Research and Innovation program created a topic for a 2007-2008 call for proposals on resilient and sustainable infrastructures. This topic argues that the nation’s infrastructures over the past century have evolved largely independently but new technologies have emerged that coupled some of these infrastructures. This has created a need for fundamental tools to design and develop these new technologies and to evolve these coupled infrastructures.
Stein and others see the PHEV as a perfect example of such a new technology that in this case is coupling the transportation and power grid infrastructures.
V2G is an opportunity to look at vehicles beyond shaving miles per gallon. A team of experts in mechanical and power systems engineering, economics, and industrial ecology will examine every aspect of a PHEV and how it interacts with the electrical grid.
If PHEVs, which are anticipated to be on the market in 2010, fulfill their promise, millions could be on the road in the decades to come. This potentially will provide unprecedented shared battery storage to the grid and transportation infrastructures, thereby allowing these infrastructures to store renewable energy when available and use it when needed.
Aging electric plants are good at generating power, Stein said, but they face challenges in storing it, and lack ways to buffer against either big surges in demands, or interruptions in supply. Massive storage systems can be costly and problematic.
But, Stein said, think of all the “distributed” storage packed into millions of PHEVs on the road. He and his colleagues envision a world where the electric cars could double as mobile holding tanks for electricity, ready to serve in their down time.
“If we had lots of PHEVs all plugged into the grid, then what seems like an insignificant amount of energy storage becomes a large energy storage,” he said.
Using gasoline-fueled conventional vehicles to generate electricity would be neither cost effective nor clean. But Stein says that hydrogen fuel cells could in the future power both the transportation and grid infrastructures. Stein and his colleagues see this as a long-term possibility likely to become more and more attractive as fuel cell costs continue to fall.
The team’s success will depend on its ability to bring together expertise in transportation and grid systems, economics, industrial ecology, and natural resources. This explains the impressive size of the team, which also includes Hosam Fathy, Zoran Filipi and Huei Peng in the Department of Mechanical Engineering; Duncan Callaway and Greg Keoleian in the School of Natural Resources and Environment; John Sullivan in the Transportation Research Institute; Jing Sun in the Department of Electrical Engineering and Computer Science and Carl Simon, in the Gerald R. Ford School of Public Policy; as well as Mariesa Crow from the Missouri University of Science and Technology.
The four-year project has several components, including:
* Designing new generations of PHEV powertrains, grid systems, and intelligent controllers for these powertrains and systems, to maximize the benefit of V2G integration.
* Understanding the impacts of PHEVs – no small task since the supply chains for an automobile contain some 20,000 parts and components – and from there developing environmental and energy sustainability models. The research team will look at life-cycle assessment, that is, understanding how energy is distributed through a system throughout its life, what kind of demands PHEV will place on the electric grid, and what needs the grid will have.
* Building computer models to help understand and predict market penetration of PHEVs. The team will evaluate the long-term sustainability of joining transportation and electricity systems.
* Developing models to understand how PHEVs can influence the reliability and stability of the electrical grid. The team will look at issues both of resilience and redundancy---how well a system can shift to a back up plan. The models they create ultimately can be turned over to industry.
“Only by applying thoughtful, well developed science will the nation be able to make the right decisions to effectively address our energy challenges,” said Gary Was, director of the Michigan Memorial Phoenix Energy Institute which develops, coordinates and promotes multidisciplinary energy research and education at U-M. “This project will provide policy makers, industry leaders and the public with critical information so that they can make well informed decisions. It is the new face of informed decision making.”
http://www.sciencedaily.com/releases/2008/10/081002172140.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #296 on Oct 4, 2008, 11:59am » | |
Baked Slug: New Method To Test Fireproofing Material
![[image]](http://img114.imageshack.us/img114/6486/081002172144large943495jw3.jpg "[image]")
Microtomography image of the pore structure of a fireproofing material. The different colors identify different individual pores within the material, whose size and shape have a large influence on the thermal conductivity of the material at high temperatures. (Credit: NIST)
ScienceDaily (Oct. 2, 2008) — In a high-temperature blaze, how well does a fireproofing material shield a building’s important steel structures from heat? Answering this question has been surprisingly difficult, but it is important information for builders selecting high-performance fire-resistive materials and for scientists conducting computer simulations that investigate fires.
Now, researchers at the National Institute of Standards and Technology (NIST) and their colleagues have developed a technique for measuring a key thermal property of fire-resistive materials at high temperatures. The measurement technique has already been adopted commercially and incorporated into a national standard.*
In creating computer simulations to study the collapses of the World Trade Center buildings on Sept. 11, 2001, NIST researchers needed to know important properties of the fireproofing materials that protected structural steel columns. One key property was the thermal conductivity of the material: How quickly does heat transfer through it? Thermal insulation has a low thermal conductivity and metals have a high thermal conductivity.
There are long-established methods for measuring thermal conductivity under ambient conditions, but a material’s thermal conductivity can change markedly when it is subjected to extremely high temperatures that cause important chemical and structural changes. Traditional methods for measuring thermal conductivity at high temperatures have not been adequate. They have relied on “hot wire” techniques, which use wire probes to measure heat flow through a wire surrounded by the material of interest. At sufficiently elevated temperatures, the material can separate from the wire preventing the measurement of the thermal conductivity in a highly heated material.
NIST’s Dale Bentz and his colleagues developed a “slug calorimeter” technique for obtaining the thermal conductivity information at elevated temperatures. In this technique, they use a thin square slab of steel material known as a slug and sandwich it between slabs of the fireproofing material of interest. Guard insulation surrounds the sides of the sample so that heat flows preferentially through the sandwich when it is placed in a high-temperature furnace. Three temperature probes inserted into the steel slug measure the heat flowing to the steel. Combining this data with the known heat capacities and densities of the steel slug and the fire-resistive material, the researchers can determine the material’s thermal conductivity at various temperatures.
Following the successful demonstration of this method at NIST, two large U.S. testing labs have worked with NIST to develop their own in-house slug calorimeters as a testing service to their clients, and a third U.S. company recently introduced a commercial version of a slug calorimeter. ASTM International (formerly the American Society for Testing and Materials) has published a standard (ASTM E 2584) detailing how to conduct thermal conductivity measurements with the new method. Possible applications beyond steel fireproofing material, Bentz says, involve measuring the thermal conductivity of wood-based materials, as well as the insulating materials used to protect spacecraft such as the Space Shuttle.
* D.P. Bentz, D. Flynn, J.H. Kim and R.R. Zarr. Fire Materials, 2006; 30:257-270; and ASTM Standard E 2584-07, “Standard Practice for Thermal Conductivity of Materials.”
http://www.sciencedaily.com/releases/2008/10/081002172144.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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| | Re: New Millenium Technology IV
« Reply #297 on Oct 4, 2008, 12:15pm » | |
Coastlines Could Be Protected From Large Water Waves By Invisibility Cloak
![[image]](http://img151.imageshack.us/img151/310/0810020948420392325ev6.jpg "[image]")
The 'invisibility cloak' consists of pillars that guide water along corridors to its centre. (Credit: Image courtesy of University of Liverpool)
ScienceDaily (Oct. 2, 2008) — Scientists at the University of Liverpool have tested an ‘invisibility cloak’ that could reduce the risk of large water waves overtopping coastal defences.
Mathematicians at Liverpool, working with physicists at the Centre National de la Recherche Scientifique (CNRS) and Aix-Marseille Universite have found that coastal defences could be made ‘invisible' when water is guided through a special structure called metamaterial.
Metamaterial was first invented by Sir John Pendry at Imperial College London where scientists discovered that this unique structure could bend electromagnetic radiation – such as visible light, radar or microwaves – around a spherical space, making an object within this region appear invisible.
The new structure is cylindrical and consists of rigid pillars that help guide water along concentric corridors. The pillars interact with the water, guiding it in different directions along the corridors and increasing its speed as it nears the centre of the structure - similar to a whirlpool. The water waves, however, are never broken-up and exit the structure as though they had never been disturbed.
Dr Sebastien Guenneau, from the University’s Department of Mathematical Science, explains: “Defending land against flooding and tidal waves is a big issue for scientists and engineers all over the world. Coastal defences have to withstand great forces and there is always a risk of water overtopping or penetrating these structures. Water crashes against these defences, breaking the wave and causing a lot of damage to roads and property hidden behind them.
“What is unique about this new structure is that it interacts with the water, guiding it to a particular destination rather than breaking it up and sending it everywhere. It is as though the defences are invisible to the wave and as such it does not recognise the structure as an obstacle. This makes it easier to manipulate water waves.
“We now need to investigate how to replicate this effect in a ‘real’ life situation to protect land from natural disasters such as tsunamis, and defend other structures such as oil rigs in the ocean.”
The research is published in Physical Review Letters.
http://www.sciencedaily.com/releases/2008/10/081002094842.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #298 on Oct 4, 2008, 12:16pm » | |
Using Molecules To Measure Rate Of Flow
ScienceDaily (Oct. 2, 2008) — Dutch researcher Jeroen Bominaar has developed a new measurement technique based on following molecules in a (turbulent) airflow. Its main advantage is that no measuring instruments or small particles, such as glass beads, need to be inserted into the flow.
These techniques fail if, for example, the particle density is too low or the measurement techniques influence the flow. Bominaar's research was part of a project funded by Technology Foundation STW.
Jeroen Bominaar set out to improve the new measurement technique, apply it and study its effect. The method involves directing a focused laser beam in a single line in an airflow, which results in some of the nitrogen and oxygen molecules in the line being converted into nitric oxide molecules. Shortly afterwards the line of new molecules is irradiated with a second laser and this causes the molecules to fluoresce. As these molecules move with the airflow, the speed of the airflow can be accurately measured.
The technique can be used in situations where current particle techniques fall short of the mark, for example, in accurate speed measurements in wind tunnels, on satellite engines or in the wake of moving objects. ILA GmbH, NMi, Philips Research and NLR were industrial partners in the research project.
http://www.sciencedaily.com/releases/2008/09/080929093752.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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Big Bunny
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| | Re: New Millenium Technology IV
« Reply #299 on Oct 4, 2008, 12:19pm » | |
Why Metal Alloys Degrade And Fail
![[image]](http://img376.imageshack.us/img376/3639/0809241752000639524cc7.jpg "[image]")
Jet turbine. Metal alloys can fail unexpectedly in a wide range of applications --- from jet engines to satellites to cell phones --- and new research from the University of Michigan helps to explain why. (Credit: iStockphoto/Maciej Noskowski)
ScienceDaily (Oct. 2, 2008) — Metal alloys can fail unexpectedly in a wide range of applications---from jet engines to satellites to cell phones---and new research from the University of Michigan helps to explain why.
Metal alloys are solids made from at least two different metallic elements. The elements are often mixed together as liquid, and when they "freeze," into solids, tiny grains of crystal form to create a polycrystalline material. A polycrystalline material is made of multiple crystals.
Within each of the grains of crystal, atoms are arranged in a periodic pattern. This pattern isn't perfect, though. For example, some of the places atoms should be are empty. These empty spaces are called vacancies. Atoms of each element in the alloy take advantage of these holes in the lattice. In a process called diffusion, atoms hop through the material, changing its structure.
"It's kind of like musical chairs," said Katsuyo Thornton, assistant professor in the U-M Department of Materials Science and Engineering. "Diffusion happens in nearly every material, and materials can degrade because diffusion causes certain changes in the structure of the material."
Atoms of different elements tend to hop at different rates because they are bound to their surrounding atoms with varying strength. Thornton and her colleagues have demonstrated that when there's a greater discrepancy in the hop rates in the different elements in the alloy, there's a more pronounced diffusion along grain boundaries. This possibly leads to a faster degradation. Thornton's collaborators on this project are Materials Science and Engineering doctoral student Hui-Chia Yu, and Anton Van der Ven, an assistant professor in the same department.
"In some cases, the grain-boundary diffusion is 100 times higher than what was commonly expected," Thornton said.
"This is a very generic finding," she said. "That's why it's important. It applies to a wide variety of materials. It applies to polycrystalline materials including electronic materials like solder."
Conventional solder, made of tin and lead, is a common alloy that connects electronic components in computer circuit boards and gadgets. Because lead is toxic, engineers are working to design new kinds of solder without lead. But they haven't found a substitute that works as well. The team's findings may help explain why "tin whiskers" form in some of these new solders. Tin whiskers have caused damage to satellites, for example.
"We are trying to apply this theory to whisker growth in solder," Thornton said.
This finding suggests that materials scientists could make longer-lasting alloys if they use metals with similar atomic hop rates, or manipulate the intrinsic hop rates by other mechanisms.
Journal reference:
1. Yu et al. Theory of grain boundary diffusion induced by the Kirkendall effect. Applied Physics Letters, 2008; 93 (9): 091908 DOI: 10.1063/1.2978161
http://www.sciencedaily.com/releases/2008/09/080924175200.htm
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"All truth passes through three stages. First, it is ridiculed, second it is violently opposed, and third, it is accepted as self-evident."
Arthur Schopenhauer, Philosopher, 1788-1860
"In the final analysis, our most basic common link is that we all inhabit this small planet, breathe the same air, and we all cherish our children’s future."
John F. Kennedy |
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