Tuesday, May 26, 2015

"Slinky" Lens Could See Cancer and Other Tiny Objects

Looking like a miniature Slinky, a new lens can manipulate and resolve light in ways impossible for traditional lenses. Researchers say this "hyperlens" may help detect early-stage cancer and identify single molecule sequences. 
This "Slinky" hyperlens measures a few micrometers across. The light-colored, grainy layers are made of gold and the darker, smoother layers are made of a transparent thermoplastic, PMMA. The two slits in the gold at the bottom of the arch create a 250-nanometer-wide object to image. Credit: Sun et al. 2015.
Resolving two points near the diffraction limit
as the spacing between them decreases.
Eventually the two points merge in a blur.
Credit: Public domain
Traditional lenses can only resolve so much detail. A fundamental "diffraction limit" prevents microscopes from imaging features smaller than about half the wavelength of light used. For yellow light with a wavelength of 780 nm, this limit is about 390 nm. Any object or feature smaller than this, including viruses, proteins, and many molecules, would simply be a blur in traditional microscopes.

Now researchers at the University at Buffalo have engineered a new type of lens that breaks this barrier and resolves objects to at least 250 nm using yellow light, as they describe in a recent paper in Nature Communications.

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Friday, May 22, 2015

Good Vibrations For Computations

Image credit: Stefan Kontur| http://bit.ly/1PtZ2IG
Rights information: http://bit.ly/cEcCkh
Electronic computers, like the one you're using to read this story, are a fantastically successful technology, having grown in just 70 years into a bedrock of the global economy. But within the next decade, experts say computer and personal electronics designers will start to reach the physical limits of how small and fast such devices can get.
Some physicists are now trying to put a new spin on the technology, by building computers that would store, move and process information using vibrations in solid materials.

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Thursday, May 21, 2015

Physics in Verse: Maxwell's "I come from fields of fractured ice..."

Here's another lovely bit of physics poetry. Last week it was John Updike on neutrinos. This week it is Scottish mathematican and physicist, James Clerk Maxwell, who is most famous for his theory of electromagnetic radiation (commonly known as Maxwell's equations).

James Clerk Maxwell and his wife, Katherine,
circa 1869. Credit: Public domain
Maxwell was the first person to realize that magnetic and electric fields are intimately related, and that light (ranging from radio waves to visible light to gamma rays) is the result of oscillating electromagnetic fields.

On the side, Maxwell enjoyed reading and writing poetry, and many of his poems survive in a collection published by his life-long friend, Lewis Campbell, in 1882.

This poem, "To The Chief Musician Upon Nabla: A Tyndallic Ode", describes the magic and allure of physical phenomena. Maxwell composed it for his friend and fellow-physicist, Peter Guthrie Tait, and first published it anonymously in Nature in 1871, during the final decade of Maxwell's life.

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Wednesday, May 20, 2015

Holograms in Everyday Life: Going to the Movies

As someone who has trouble understanding and following movies without subtitles, I got into the habit of not jumping to go see new movies in the theater growing up. My local theaters’ closed captioning devices were these small, LED screens you could set in a cup holder that would provide titles, and did not lend themselves to easy viewing experiences. A few years ago, Regal Entertainment theaters began rolling out Sony holographic glasses that project captions. In addition to providing a better visual experience for viewing closed captions in movies, it puts to use some interesting physics.

Sony Entertainment Access Glasses. Image Credit: Sony Product Details

It’s hard to say exactly how the glasses work - it's in Sony's best interested not to disclose all the technical specs - but we can make some solid guesses. In 2008, scientists from Sony published a white paper on a full-color version of the holographic glasses that look similar to the glasses that you can pick up at the movie theater.

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Tuesday, May 19, 2015

Octopus-inspired Robotic Arm Manipulates "Organs"

The strength and flexibility of an octopus arm has inspired Italian researchers from the Sant'Anna School of Advanced Studies to create a robotic tool that may assist in future keyhole surgeries.

An octopus-inspired robotic arm adapts to delicate objects in its environment.
Image courtesy of Tommaso Ranzani, The BioRobotics Group, Sant'Anna School of Advanced Studies

Much like the dexterous limb of an octopus, which can weave around corners and grasp objects, this prototype arm can perform multiple tasks at the same time, potentially reducing the number of tools needed in a surgery. By adjusting the stiffness in different parts of the same arm, the researchers hope to prevent damage to soft organs (represented by water balloons in their lab experiments).

"The human body represents a highly challenging and non-structured environment, where the capabilities of the octopus can provide several advantages with respect to traditional surgical tools," said lead author Tommaso Ranzani in an Institute of Physics press release.

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Monday, May 18, 2015

How Ants Go Marching And Never Cause Traffic Jams

Traffic scientists study ants because they manage traffic better than humans.

Originally published: May 11 2015 - 12:45pm, Inside Science News Service
By: Joel N. Shurkin, Contributor

(Inside Science) -- The old children's song about marching ants is a good explanation for why traffic engineers love them.

Ants -- most are teeny creatures with brains smaller than pinheads -- engineer traffic better than humans. Ants never run into stop-and-go-traffic or gridlock on the trail. In fact, the more ants of one species there are on the road, the faster they go, according to new research.

Image credit: Clicksy via flickr | http://bit.ly/1G06cyj
Rights information: http://bit.ly/NL51dk
Researchers from two German universities, the Universities of Potsdam and the Martin Luther University of Halle-Wittenberg, found a nest of black meadow ants (Formica pratensis) in the woods of Saxony. The nest had four trunk trails leading to foraging areas, some of them 60 feet long. They chose a small area and set up a camera that took time-lapse photography, and recorded the ants coming through the zone.

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Friday, May 15, 2015

The Amtrak Derailment And Newton's First Law

Walter Siegmund via wikimedia | http://bit.ly/1HjxEbL
Tuesday evening's deadly derailment that sent an Amtrak Northeast Regional train careening off its tracks has many people asking how such a tragedy could happen. Investigators on the case have not announced an official cause just yet, but it seems that speed played a major factor: the train was, apparently, traveling down the track at 106 mph, more than 50 mph over the posted speed limit on the bend where the train derailed, according to National Transportation Safety Board member Robert Sumwalt.
On a purely physical level, the train's derailment due to excessive speed can be understood in terms of Newton's first law of motion: an object in motion tends to stay in motion and an object at rest tends to stay at rest unless acted upon by an outside force.

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Thursday, May 14, 2015

A Sharper Focus in Underwater Sound Images

Murky water is an excellent cloak, masking underwater features and objects from view. Sound can pierce straight through the murk by traveling around suspended particles in the water with minimal scattering. But sound's penetrating ability, thanks to its relatively long wavelengths, also means that it is difficult to "see" underwater objects in any detail. Scientists are currently developing a new sonar technique that can image objects only a few inches in size.

For more than a hundred years, scientists have used sonar (SOund Navigation And Ranging) to pierce underwater depths, but the most common technique, called side-scan sonar, works best on very large objects like shipwrecks or the contours of the ocean floor.

Image of the shipwreck "Aid" in Estonia using side-scan sonar.
Credit: Subzone OÜ via Wikimedia Commons

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Tuesday, May 12, 2015

The Physics of Sailing: How Does a Sailboat Move Upwind?

Have you ever wondered how a sailboat sails upwind?

Sailboats racing upwind. Credit: Public domain

The sun is out, the wind is blowing, and I've been busy taking some sailing lessons. Turns out there's an interesting bit of physics that allows sailboats to not only travel downwind, being pushed by the wind, but also to travel upwind, or nearly so.

An 18th-century square-rigged ship sailing
downwind. Credit: Public domain
But first let's start with the downwind case. If the sailor wants to travel in the same direction as the wind, then all he or she has to do is hold the sail perpendicular to the wind and let the boat be pushed from behind.

This is the most basic point of sail, and was often used by ancient Egyptian, Greek, and Roman sailors. When they needed additional speed or wanted to travel upwind, they rowed.

The large square-rigged boats popular in the 18th and 19th centuries (the classic pirate ship, for instance) were also most effective on a downwind sail.

Modern sailboats can sail in any direction that is greater than about 45 degrees with respect to the wind. They can't sail exactly upwind but with a clever boat design, a well-positioned sail, and the patience to zig-zag back and forth, sailors can travel anywhere.

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Monday, May 11, 2015

Physics in Verse: A John Updike Poem about Neutrinos

There is a long history of poets taking Nature as their muse, from the call of the sea to the draw of the wild. But poems about physics phenomena are harder to find.

Some might argue that physicists and poets have little in common: particle physicist Paul Dirac once commented, "In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in the case of poetry, it's the exact opposite!"

But Dirac was also a firm believer in the inherent beauty of his theories and perhaps would not mind the overlap of physics and poetry that celebrates the magical and beautiful workings of the physical world.

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