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Resolve your vision issues efficiently using Laser Technology Vision

Clar — Thu, 05 Jan 2012 06:26:43 +0000

Today, there is a rapid advancement of technology in every field and ophthalmology is not excluded. Laser technology vision is one good example of the technology innovation. People who suffer with poor eye sight know how frustrating this situation can be. However, there is nothing to worry about. Today, with the use of laser technology, you can resolve various vision issues in style.

Using glasses to overcome poor eye sight is good to some extent. However, beauty conscious people are not happy with glasses. Contact lens can serve the purpose to some extent. However, you need to maintain them in a careful manner. With the laser technology you can get rid of all these issues and wear a great look permanently. The process involved in the laser treatment is simple and is affordable by most people. The success rate of this laser technology for vision issues is high. This is why most people prefer laser technology vision treatment to other alternate methods.

New method for enhancing thermal conductivity could cool computer chips, lasers and other devices

las_pla — Thu, 05 Jan 2012 05:56:46 +0000

The surprising discovery of a new way to tune and enhance thermal conductivity — a basic property generally considered to be fixed for a given material — gives engineers a new tool for managing thermal effects in smart phones and computers, lasers and a number of other powered devices.
The finding was made by a group of engineers headed by Deyu Li, associate professor of mechanical engineering at Vanderbilt University, and published online in the journal Nature Nanotechnology on Dec. 11.
Li and his collaborators discovered that the thermal conductivity of a pair of thin strips of material called boron nanoribbons can be enhanced by up to 45 percent depending on the process that they used to stick the two ribbons together. Although the research was conducted with boron nanoribbons, the results are generally applicable to other thin film materials.
An entirely new way to control thermal effects
“This points at an entirely new way to control thermal effects that is likely to have a significant impact in microelectronics on the design of smart phones and computers, in optoelectronics on the design of lasers and LEDs, and in a number of other fields,” said Greg Walker, associate professor of mechanical engineering at Vanderbilt and an expert in thermal transport who was not directly involved in the research.
According to Li, the force that holds the two nanoribbons together is a weak electrostatic attraction called the van der Waals force. (This is the same force that allows the gecko to walk up walls.)
“Traditionally, it is widely believed that the phonons that carry heat are scattered at van der Waals interfaces, which makes the ribbon bundles’ thermal conductivity the same as that of each ribbon. What we discovered is in sharp contrast to this classical view. We show that phonons can cross these interfaces without being scattered, which significantly enhances the thermal conductivity,” said Li. In addition, the researchers found that they could control the thermal conductivity between a high and a low value by treating the interface of the nanoribbon pairs with different solutions.
The enhancement is completely reversible
One of the remarkable aspects of the effect Li discovered is that it is reversible. For example, when the researchers wetted the interface of a pair of nanoribbons with isopropyl alcohol, pressed them together and let them dry, the thermal conductivity was the same as that of a single nanoribbon. However, when they wetted them with pure alcohol and let them dry, the thermal conductivity was enhanced. Then, when they wetted them with isopropyl alcohol again, the thermal conductivity dropped back to the original low value.
“It is very difficult to tune a fundamental materials property such as thermal conductivity and the demonstrated tunable thermal conductivity makes the research especially interesting,” Walker said.
One of the first areas where this new knowledge is likely to be applied is in thermal management of microelectronic devices like computer chips. Today, billions to trillions of transistors are jammed into chips the size of a fingernail. These chips generate so much heat that one of the major factors in their design is to prevent overheating. In fact, heat management is one of the major reasons behind today’s multi-core processor designs.
“A better understanding of thermal transport across interfaces is the key to achieving better thermal management of microelectronic devices,” Li said.
Discovery may improve design of nanocomposites
Another area where the finding will be important is in the design of “nanocomposites” — materials made by embedding nanostructure additives such as carbon nanotubes to a host material such as various polymers — that are being developed for use in flexible electronic devices, structural materials for aerospace vehicles and a variety of other applications.
Collaborators on the study were post-doctoral research associate Juekan Yang, graduate students Yang Yang and Scott Waltermire from Vanderbilt; graduate students Xiaoxia Wu and Youfei Jiang, post-doctoral research associate Timothy Gutu, research assistant professor Haitao Zhang, and Associate Professor Terry T. Xu from the University of North Carolina; Professor Yunfei Chen from the Southeast University in China; Alfred A. Zinn from Lockheed Martin Space Systems Company; and Ravi Prasher from the U.S. Department of Energy.
The research was performed with financial support from the National Science Foundation, Lockheed Martin’s Engineering and Technology University Research Initiatives program and the Office of Naval Research.

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New method for enhancing thermal conductivity could cool computer chips, lasers and other devices

Stress causes clogs in coffee and coal

las_pla — Thu, 05 Jan 2012 05:56:46 +0000

It’s easy to get in a jam. But it’s much harder to explain exactly how or when it started.
Scientists still aren’t sure what causes clogs in flowing macroscopic particles, like corn, coffee beans and coal chunks. But new experiments by Duke physicist Robert Behringer and his colleagues suggest that when particles undergo a force called shear strain, they jam sooner than expected. The results appear in the Dec. 15 issue of Nature.
Shear strain is sort of like cupping sand between your hands, and then, without changing the width between them, moving one hand forward and the other hand backward, Behringer said. Not much sand flows between your hands with a force like this.
Many flows, including those of nuts, coffee and coal, inherently produce this type of movement among grains, but the design and engineering for hoppers and other dispensers that don’t account for it won’t work well, Behringer said.
The new work “points out the deficiencies in our current theoretical framework for when granular materials jam,” said Corey O’Hern, an expert in granular media at Yale University who was not involved in the new study.
A deeper understanding of this point will lead to the design of new composite granular matter and also to the development of advanced materials that could counter weapons of mass destruction, including amplifiers and other countermeasures for deflecting blast waves, he said.
In past studies, physicists calculating how grains flow estimated their jamming point without accounting for friction forces among individual particles. Eliminating friction makes jamming easier to explain mathematically. It also suggested that just an increase in density would cause granular materials to jam.
“It’s been an uphill battle to convince the scientific community that friction is important, and that shear causes jamming where it was not expected. No other experimentalists have really looked at what’s happening with both friction and shear,” Behringer said.
In his new experiments, Behringer and his team controlled the number of discs placed in a box designed to produce a shear strain. The researchers applied the shearing strain while allowing the discs to flow where they wanted.
The discs had distinct properties that allowed the team to measure the force each one experienced due to friction and shearing. The team also took pictures showing how those forces developed into branched chains, which spread through many discs and ultimately block their flow. The images and experiments show that because of friction forces and shear strain, the discs jammed when they were much farther apart, or at a lower density, than what had been previously predicted.
It’s not just the number of particles that put them in a jam, it’s also the strain and the real-world forces, like friction, that cause the back-up, Behringer said. The discovery could change the design of coal and grain silos and even the bulk dispensers at Whole Foods.
Friction and shear reveal the richness of possible states of granular matter, pointing scientists down a road paved with new discoveries, said Daryl Hess, program director for condensed matter and materials theory at NSF. Studying these new states of granular matter may also expose deeper connections between jamming and seemingly unrelated phenomena, from earthquakes to transformations occurring in other kinds of matter, like water to ice, he said.

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Stress causes clogs in coffee and coal

‘Green routing’ can cut car emissions without significantly slowing travel time

las_pla — Thu, 05 Jan 2012 05:56:46 +0000

The path of least emissions may not always be the fastest way to drive somewhere. But according to new research from the University at Buffalo, it’s possible for drivers to cut their tailpipe emissions without significantly slowing travel time.
In detailed, computer simulations of traffic in Upstate New York’s Buffalo Niagara region, UB researchers Adel Sadek and Liya Guo found that green routing could reduce overall emissions of carbon monoxide by 27 percent for area drivers, while increasing the length of trips by an average of just 11 percent.
In many cases, simple changes yielded great gains.
Funneling cars along surface streets instead of freeways helped to limit fuel consumption, for instance. Intelligently targeting travelers was another strategy that worked: Rerouting just one fifth of drivers — those who would benefit most from a new path — reduced regional emissions by about 20 percent.
Sadek, a transportation systems expert, says one reason green routing is appealing is because it’s a strategy that consumers and transportation agencies could start using today.
“We’re not talking about replacing all vehicles with hybrid cars or transforming to a hydrogen-fuel economy — that would take time to implement,” said Sadek, an associate professor of civil, structural and environmental engineering. “But this idea, green routing, we could implement it now.”
In the near future, GPS navigation systems and online maps could play an important role in promoting green routing, Sadek said. Specifically, these systems and programs could use transportation research to give drivers the option to choose an environmentally friendly route instead of the shortest route.
Sadek and Guo, a PhD candidate, presented their research on green routing at the 18th World Congress on Intelligent Transportation Systems in October.
In the UB study on green routing, the researchers tied together two computer models commonly known as “MOVES” and “TRANSIMS.”
The Motor Vehicle Emission Simulator (MOVES), created by the Environmental Protection Agency, estimates emissions. The Transportation Analysis and Simulation System (TRANSIMS) simulates traffic in great detail, taking into account information including the location and pattern of signals; the grade of the road; and the trips people take at different times of day.
After incorporating Buffalo-specific data into TRANSIMS, Sadek and Guo ran a number of simulations, rerouting travelers in new ways each time.
After running the models numerous times, the researchers reached a “green-user equilibrium” — a traffic pattern where all drivers are traveling along optimal routes. With the system in equilibrium, moving a commuter from one path to another would increase a user’s overall emissions by creating more congestion or sparking another problem.
The simulations were part of a broader study Sadek is conducting on evaluating the likely environmental benefits of green routing in the region. His project is one of seven that the U.S. Department of Transportation has funded through a Broad Agency Announcement that aims to leverage intelligent transportation systems to reduce the environmental impact of transportation.

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‘Green routing’ can cut car emissions without significantly slowing travel time

Trillion-frame-per-second video: Researchers have created an imaging system that makes light look slow

las_pla — Thu, 05 Jan 2012 05:56:45 +0000

MIT researchers have created a new imaging system that can acquire visual data at a rate of one trillion exposures per second. That’s fast enough to produce a slow-motion video of a burst of light traveling the length of a one-liter bottle, bouncing off the cap and reflecting back to the bottle’s bottom.
Media Lab postdoc Andreas Velten, one of the system’s developers, calls it the “ultimate” in slow motion: “There’s nothing in the universe that looks fast to this camera,” he says.
The system relies on a recent technology called a streak camera, deployed in a totally unexpected way. The aperture of the streak camera is a narrow slit. Particles of light — photons — enter the camera through the slit and pass through an electric field that deflects them in a direction perpendicular to the slit. Because the electric field is changing very rapidly, it deflects late-arriving photons more than it does early-arriving ones.
The image produced by the camera is thus two-dimensional, but only one of the dimensions — the one corresponding to the direction of the slit — is spatial. The other dimension, corresponding to the degree of deflection, is time. The image thus represents the time of arrival of photons passing through a one-dimensional slice of space.
The camera was intended for use in experiments where light passes through or is emitted by a chemical sample. Since chemists are chiefly interested in the wavelengths of light that a sample absorbs, or in how the intensity of the emitted light changes over time, the fact that the camera registers only one spatial dimension is irrelevant.
But it’s a serious drawback in a video camera. To produce their super-slow-mo videos, Velten, Media Lab Associate Professor Ramesh Raskar and Moungi Bawendi, the Lester Wolfe Professor of Chemistry, must perform the same experiment — such as passing a light pulse through a bottle — over and over, continually repositioning the streak camera to gradually build up a two-dimensional image. Synchronizing the camera and the laser that generates the pulse, so that the timing of every exposure is the same, requires a battery of sophisticated optical equipment and exquisite mechanical control. It takes only a nanosecond — a billionth of a second — for light to scatter through a bottle, but it takes about an hour to collect all the data necessary for the final video. For that reason, Raskar calls the new system “the world’s slowest fastest camera.”
Doing the math
After an hour, the researchers accumulate hundreds of thousands of data sets, each of which plots the one-dimensional positions of photons against their times of arrival. Raskar, Velten and other members of Raskar’s Camera Culture group at the Media Lab developed algorithms that can stitch that raw data into a set of sequential two-dimensional images.
The streak camera and the laser that generates the light pulses — both cutting-edge devices with a cumulative price tag of $250,000 — were provided by Bawendi, a pioneer in research on quantum dots: tiny, light-emitting clusters of semiconductor particles that have potential applications in quantum computing, video-display technology, biological imaging, solar cells and a host of other areas.
The trillion-frame-per-second imaging system, which the researchers have presented both at the Optical Society’s Computational Optical Sensing and Imaging conference and at Siggraph, is a spinoff of another Camera Culture project, a camera that can see around corners. That camera works by bouncing light off a reflective surface — say, the wall opposite a doorway — and measuring the time it takes different photons to return. But while both systems use ultrashort bursts of laser light and streak cameras, the arrangement of their other optical components and their reconstruction algorithms are tailored to their disparate tasks.
Because the ultrafast-imaging system requires multiple passes to produce its videos, it can’t record events that aren’t exactly repeatable. Any practical applications will probably involve cases where the way in which light scatters — or bounces around as it strikes different surfaces — is itself a source of useful information. Those cases may, however, include analyses of the physical structure of both manufactured materials and biological tissues — “like ultrasound with light,” as Raskar puts it.
As a longtime camera researcher, Raskar also sees a potential application in the development of better camera flashes. “An ultimate dream is, how do you create studio-like lighting from a compact flash? How can I take a portable camera that has a tiny flash and create the illusion that I have all these umbrellas, and sport lights, and so on?” asks Raskar, the NEC Career Development Associate Professor of Media Arts and Sciences. “With our ultrafast imaging, we can actually analyze how the photons are traveling through the world. And then we can recreate a new photo by creating the illusion that the photons started somewhere else.”
“It’s very interesting work. I am very impressed,” says Nils Abramson, a professor of applied holography at Sweden’s Royal Institute of Technology. In the late 1970s, Abramson pioneered a technique called light-in-flight holography, which ultimately proved able to capture images of light waves at a rate of 100 billion frames per second.
But as Abramson points out, his technique requires so-called coherent light, meaning that the troughs and crests of the light waves that produce the image have to line up with each other. “If you happen to destroy the coherence when the light is passing through different objects, then it doesn’t work,” Abramson says. “So I think it’s much better if you can use ordinary light, which Ramesh does.”
Indeed, Velten says, “As photons bounce around in the scene or inside objects, they lose coherence. Only an incoherent detection method like ours can see those photons.” And those photons, Velten says, could let researchers “learn more about the material properties of the objects, about what is under their surface and about the layout of the scene. Because we can see those photons, we could use them to look inside objects — for example, for medical imaging, or to identify materials.”
“I’m surprised that the method I’ve been using has not been more popular,” Abramson adds. “I’ve felt rather alone. I’m very glad that someone else is doing something similar. Because I think there are many interesting things to find when you can do this sort of study of the light itself.”

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Trillion-frame-per-second video: Researchers have created an imaging system that makes light look slow

Physicists say they are near epic Higgs boson discovery

las_pla — Thu, 05 Jan 2012 05:56:45 +0000

The Holy Grail of high-energy physics — the predicted but elusive Higgs boson — is almost within reach, and the Brandeis high-energy physics group, along with other particle physicists around the world collaborating on making the finding, is almost giddy with excitement.
The Brandeis group has contributed since 1994 to collaborative experiments to detect the Higgs particle in the world’s largest particle accelerator, the Large Hadron Collider (LHC). CERN, the international agency in Geneva that oversees experiments in the LHC, announced Dec. 13 in a progress report the news of mounting experimental evidence for the existence of this critically important speck of nature.
“It’s very exciting,” says Brandeis physics Professor Craig Blocker, explaining that experiments in the LHC’s two detectors have amassed enough evidence of the Higgs particle to suggest much more than an unexplained blip in the data produced by trillions of protons smashing into each other at almost the speed of light.
“The data look very tantalizing but we’re not there yet,” says Blocker. “We don’t have quite enough evidence to claim a discovery but it looks promising — there’s a good indication that this particle is there, so we’ll probably be able to announce the discovery next year with more data.”
What makes the prospect of finding the Higgs particle so electrifying for physicists is that its discovery could put in place the final piece of the puzzle that describes the fundamental building blocks of matter and their interactions — hence its description as the “God Particle.” Higgs particles are thought to interact with other subatomic particles to give them mass through a phenomenon known as the Higgs mechanism.
The Higgs mechanism was first described in the 1960s by Scottish physicist Peter Higgs. A few years later, physicist Steven Weinberg applied Higgs’ ideas to weak interactions and predicted the Higgs particle. It is the only elementary particle in the Standard Model — the description of the fundamental particles and the forces that hold them together — that has not been observed experimentally yet.
Blocker says detecting the Higgs is challenging because the strength with which it interacts with other particles depends on the mass of those other particles. The Higgs itself is quite massive (for something on the subatomic level); it interacts well with other massive particles, but very poorly with lightweight particles. However, massive particles generally require higher-energy conditions than lightweight particles to record experimentally — energy levels difficult to obtain even inside the mind-boggling fast Large Hadron Collider. Consequently, says Blocker, physicists don’t obtain the signature energy decay of a Higgs boson often in the supercollider.
The growing anticipation surrounding the Higgs particle seems almost overshadowed by a gathering anxiety that physicists might actually get what they wish for — a perfectly realized prediction that completes the Standard Model. If that happens says Blocker, “we’d be unhappy — the quest is what’s interesting.”
Higgs or no Higgs, the chances of particle physicists actually arriving at what Einstein called a “theory of everything” anytime soon seem infinitesimally remote. When it comes to particle physics, says Blocker, it is much more likely that new theories will be generated with each experimental advance

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Physicists say they are near epic Higgs boson discovery

Best routes found to self-assembling 3-D shapes

las_pla — Thu, 05 Jan 2012 05:56:45 +0000

ScienceDaily (Dec. 7, 2011) — Researchers at Brown and Johns Hopkins universities have found optimal configurations for creating 3-D geometric shapes — like tiny, highly simplified geodesic domes that assemble by themselves. The Brown team developed the algorithmic tools, and the Johns Hopkins team tested selected configurations. The research may lead to advances from drug-delivery containers to 3-D sensors and electronic circuits.

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Best routes found to self-assembling 3-D shapes

One of the world’s smallest electronic circuits created

las_pla — Thu, 05 Jan 2012 05:56:45 +0000

A team of scientists, led by Guillaume Gervais from McGill’s Physics Department and Mike Lilly from Sandia National Laboratories, has engineered one of the world’s smallest electronic circuits. It is formed by two wires separated by only about 150 atoms or 15 nanometers (nm). This discovery, published in the journal Nature Nanotechnology, could have a significant effect on the speed and power of the ever smaller integrated circuits of the future in everything from smartphones to desktop computers, televisions and GPS systems.

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One of the world’s smallest electronic circuits created

New ’3-D’ transistors promising future chips, lighter laptops

las_pla — Thu, 05 Jan 2012 05:56:45 +0000

The approach could enable engineers to build faster, more compact and efficient integrated circuits and lighter laptops that generate less heat than today’s. The transistors contain tiny nanowires made not of silicon, like conventional transistors, but from a material called indium-gallium-arsenide.”Industry and academia are racing to develop transistors from the III-V materials,” Ye said. “Here, we have made the world’s first 3-D gate-all-around transistor on much higher-mobility material than silicon, the indium-gallium-arsenide.”

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New ’3-D’ transistors promising future chips, lighter laptops

Micro Digi-Cam

las_pla — Tue, 30 Aug 2011 05:51:25 +0000

The article is all about The Micro Digi-Cam (MDC) which is a laser based digital imaging and its visitors health insurance advantages.MDC is turning out to be a helpful tool for the traffic police officers.It plays a vital role in recording the image of the vehicles which violates the speed regulations and limits.Unlike other systems it gives all the useful and necessary information about the violators.Moreover its built with the tamper proof security system.

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Micro Digi-Cam