Quantum Levitation

Researchers at the school of physics and astronomy at Tel-Aviv University have created a track around which a semi-conductor can float, thanks to the phenomenon of "quantum levitation". 

This levitation effect is explained by the Meissner effect, which describes how, when a material makes the transition from its normal to its superconducting state, it actively excludes magnetic fields from its interior, leaving only a thin layer on its surface.

When a material is in its superconducting state -- which involves very low temperatures -- it is strongly diamagnetic. This means that when a magnetic field is externally applied, it will create an equally-opposing magnetic field, locking it in place.

A material called yttrium barium copper oxide can be turned into a superconductor by exposure to liquid nitrogen -- which makes it one of the highest-temperature superconductors.

In the video it appears that a puck of yttrium barium copper oxide cooled by liquid nitrogen is repelling the magnets embedded on the handheld device. It also shows that the angle of the magnet can be locked in a magnetic field. Later in the video the puck can be seen to zoom round a circular track of magnets, in the same way that Maglev high-speed trains do.

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Mapping the Dark Matter

When the Euclid mission lifts off at the end of this decade, it will map galaxy clusters in infrared and visible light, helping to blueprint the large-scale structure of the universe. And a bunch of amateur science geeks who signed up for the competition will use their specialized skills to elucidate those findings.

The Mapping Dark Matter competition proves that Arabic handwriting analysis, glaciology and particle physics are more relevant to cosmology than anyone would have thought — and that when you ask people to solve problems for bragging rights, you get some very creative results. 

NASA’s Jet Propulsion Laboratory sponsored the competition in cooperation with Kaggle, a startup that hosts prediction and data modeling competitions. In all, 73 teams signed up to measure the ellipticity of galaxies in astronomy images, a key element in studying cosmology's dark materials. Physics professor David Kirkby and graduate student Daniel Margala from the University of California-Irvine won the prize and brought their findings to JPL last week.

The problem: estimating the shapes of simulated postage-stamp-sized galaxy images that had been deliberately blurred. Kirkby’s background is in particle physics, but he’s interested in cosmology, so he was intrigued when he saw the competition online.

“It’s hard to get into a new area of research, because so much has already gone on before, and there’s so much jargon, it’s hard to work with the data,” Kirkby said in an interview. “But because this was a competition, it was a really well-designed problem. It posed the question in a way that was really easy for us to understand and jump in — they wanted to bring in unique ideas to work on the problem.”

And it worked. Right off the bat, Martin O’Leary, a Ph.D student in glaciology from Cambridge University, spends most of his time studying satellite images to detect the edges of glaciers; his techniques also applied to determining galactic edges. Then teammates Eu Jin Lok, an Australian graduate student at Deloitte, and Ali Hassaine, a signature verification specialist from Qatar University, built on O’Leary’s findings. Kirkby and Margala built an artificial neural network and were able to come up with the most accurate values for the galaxies’ ellipticity.

Jason Rhodes, an astrophysicist at JPL and an investigator on the Euclid mission, said the results will likely be incorporated into future algorithms that will measure real data.

“We’ll have the best quality of data from Euclid, and we need these techniques to fully exploit that data,” he said.

Looking for dark matter is something like looking for the wind — it’s invisible, but you can tell it’s there because of its impact on other objects. (Obviously wind has more observable effects than dark matter, but you get the idea.) Just as you might study a waving flag to infer that it’s windy, dark matter researchers look at warps in galaxy light to infer that the dark matter is present.

The image above, of the Bullet Cluster, is probably the best example of this. It depicts two colliding clusters of galaxies that have passed through one another at unspeakably energetic speeds. As they moved past each other in opposite directions, the stars slowed down a little, and the hot gas, which is the pinkish areas, slowed down a lot. But the dark matter, which doesn’t interact with anything except gravitationally, didn’t slow down. It is represented in blue here, way ahead of the rest of the material in these clusters. It’s not directly visible in this image; the blue shading is inferred from the effect that its gravity has on background radiation. The gravity of dark matter acts like a lens, warping the passing light.

Think of a penny in a pool of water — the penny you see is distorted because the light reflecting off it has to travel through water, Rhodes explained.

“In the same way, a very distant galaxy has a shape that we see as distorted, as it is moving through the intervening dark matter,” he said.

To know how much the light has been distorted, you’d need to know the shape of the object emitting it — a galaxy that looks warped might just be a particularly ovoid galaxy. Determining galactic ellipticity helps astronomers determine how much of that ellipticity is the result of dark matter. 

Kirkby and Margala came up with a model for each galaxy, involving six or seven different parameters. This global view, rather than looking at each data point on its own, was a novel approach, according to Rhodes. Then they fed the data into an artificial neural network, which they used to find the galaxies’ elliptical shapes. Kirkby said he planned to write a paper about his work. 

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How water cuts through steel?

A waterjet is a tool used in machine shops to cut metal parts with a (very) high-pressure stream of water. As amazing as it sounds, if you get water flowing fast enough it can actually cut metal. 

Think of a waterjet as something with about 30 times the pressure of the power washer wand at your local car wash. Power washing at car washes is an everyday example of a dirt film being "cut" off the body, wheels and tires of an automobile. 

The key to cutting metal with water is to keep the spray coherent. Waterjets are able to cut because the spray is channeled through a very narrow jeweled nozzle at a very high pressure to keep the spray coherent. Unlike metal cutters, a waterjet never gets dull and it cannot overheat. 

Low pressure waterjets were first used for mining gold in California in 1852. Steam and hot water jets were used in the early 1900s for cleaning. High pressure waterjets were used for mining in the 1960s, and about 10 years ago industry began using waterjets for cutting. Abrasive water jets (abrasivejets) were first used in industry in about 1980. 

In the past, only one piece of metal could be cut at a time with a saw or other metal cutting mechanical process. It was time intensive and expensive. Computer-controlled waterjet and abrasivejet cutting are used today in industry to cut many soft and hard materials. The plain water-abrasive mixture leaves the nozzle at more than 900 mph. The latest machines can cut to within two thousandths of an inch, and have jet speeds around Mach 3.

Waterjets can cut:

• Marble
• Granite
• Stone
• Metal
• Plastic
• Wood
• Stainless steel 

A water jet can cut a "sandwich" of different materials up to four inches thick. This odorless, dust-free and relatively heat-free process can also cut something as thin as five thousandths of an inch. The tiny jet stream permits the first cut to also be the final finished surface. This single cutting process saves material costs and machining costs. For example, the engineer merely gives a gear drawing to the cutting shop via a diskette or e-mail and gets the finished gear back.  

Waterjets cut softer materials, while abrasive jets are used for harder materials. The actual cutting is often done under water to reduce splash and noise. Faster feed rates are used to prevent the jet from cutting all the way through. 

 

The water pressure is typically between 20,000 and 55,000 pounds per square inch (PSI). The water is forced through a 0.010" to 0.015" in diameter orifice (hole) in a jewel. 

A waterjet can remove the bark from a tree at a distance of 40 feet if one alters the chemistry of plain water by adding SUPER-WATER®, available from Berkeley Chemical Research. The SUPER-WATER® is a soluble polymeric chemical that acts like a series of molecular spinal columns or concrete reinforcement bars that tie the individual water molecules together in a more structured way to form a coherent jet. Imagine the potential for cutting down roadside weeds.

How fast does a waterjet cut?

An abrasive jet can cut half-inch thick titanium at the rate of 7 inches per minute when a 30 HP pump is used. The abrasive jet moves in a manner very similar to a slowed-down pen plotter.

Abrasive jets have been used to:

• Remove materials inside train tunnels
• Help rescue "Baby Jessica" from the well in Midland, Texas
• Cut virtually any shape in bullet-proof glass
• Cut out the parts for the F-22 and Stealth bomber, and other aircraft and spacecraft
• Cut into the hull, using diamond powder abrasive, of the submarine Kursk to recover the bodies of the Russian crew
• Remove highway marking strips
• Carve wooden signs
• Create sculpture
• Cut logs in a sawmill 

Industries that can use abrasive waterjet and abrasivejet technologies:

• Building: Patterns in stone material for floors can be cut. Matching parts of a lettered sign, made from stone and metal can be cut. Special shapes for metal and tile roofs can be cut.
• Manufacturing: Precise gears and other intricate parts such as parts made of foam and rubber can be cut without use of any heat, like a laser would produce.
• Designers: Intricate shapes can be cut for jewelry, sculptures, and mirrors.
• Other: Waterjets are used to cut candy bars and diapers, too. There is a special drilling bit for oil exploration that has waterjets on the bottom to speed the drilling process. When used with a directional jets, a waterjet can bore under a road to route fiber optic cable.

Click the pressure reading to see and hear 5-second movie clip of a Flow Corporation abrasivejet. A 50 HP pump creates 52,400 PSI pressure for a jet of water and garnet abrasive mixture to cut 1/16-inch steel. This abrasivejet has an internal .013" ruby orifice to produce a .040" diameter jet of water. Look for a few sparks to fly! 

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Better Wind Turbines From Carbon Nanotube-Reinforced Polyurethane

Carbon nanotube-reinforced polyurethane could make for lighter and more durable wind turbine blades.

In the effort to capture more energy from the wind, the blades of wind turbines have become bigger and bigger to the point where the diameter of the rotors can be over 100 m (328 ft). Although larger blades cover a larger area, they are also heavier, which means more wind is needed to turn the rotor.

The ideal combination would be blades that are not only bigger, but also lighter and more durable. A researcher at Case Western Reserve University has built a prototype blade from materials that could provide just such a winning combination.

The new blade developed by Marcio Loos, a post-doctoral researcher in the Department of Macromolecular Science and Engineering, is the world's first polyurethane blade reinforced with carbon nanotubes. Using a small commercial blade as a template, Loos manufactured a 29-inch (73.6 cm) blade that is substantially lighter, more rigid and tougher than conventional blades. Rigidity is important because as a blade flexes in the wind it loses the optimal shape for catching air, so less energy is captured.

Working with colleagues at Case Western Reserve, and investigators from Bayer Material Science in Pittsburgh, and Molded Fiber Glass Co. in Ashtabula, Ohio, Loos compared the properties of the new materials with that of conventional blades manufactured using fiberglass resin.

"Results of mechanical testing for the carbon nanotube reinforced polyurethane show that this material outperforms the currently used resins for wind blades applications," said Ica Manas-Zloczower, professor of macromolecular science and engineering and associate dean in the Case School of Engineering.

Comparing reinforcing materials, the researchers found that the carbon nanotubes are lighter per unit of volume than carbon fiber and aluminum and had five times the tensile strength of carbon fiber and more than 60 times that of aluminum.

Meanwhile, fatigue testing showed the reinforced polyurethane composite lasts about eight times longer than epoxy reinforced with fiberglass, while delamination fracture tests showed it was also about eight times tougher.

The performance of the material was even better when compared against vinyl ester reinforced with fiberglass, another material used to make wind turbine blades. Fracture growth rates were also a fraction of that found for traditional epoxy and vinyl ester composites.

Loos and her team are now working to determine the optimal conditions for the dispersion of the nanotubes, the ideal distribution within the polyurethane and the ways to achieve both.

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From Spider Silk Artificial Skin

After 35 days of culturing, nearly 98 percent of the cells were detected as being vital (green), with dead cells (red) rarely observed

The secret to creating artificial skin might be spider silk, researchers now suggest.
Skin grafts are vital for treating burn victims and other patients. For instance, chronic wounds such as bedsores in hospitalized patients afflict 6.5 million in the United States alone for estimated costs of $25 billion annually.

Instead of using skin from a body for a graft, scientists are investigating artificial skin. Ideally such a graft would be of a material tolerated by the body, have skin cells embedded within it to replace lost tissue, degrade safely over time as the new skin grows in and be strong enough to withstand all the rigors ordinary skin experiences. Materials investigated until now did not seem strong enough for the task, said tissue engineer Hanna Wendt at Medical School Hannover in Germany.

Now Wendt and her colleagues suggest silk might be up for the job.
Spider silk is the toughest known natural material. Moreover, there is abody of folklore dating back at least 2,000 years regarding the potential medical value of webs — for instance, in fighting infections, stemming bleeding, healing wounds and serving as artificial ligaments.

The extraordinary strength and stretchiness of spider silk "are important factors for easy handling and transfer of many kinds of implants," Wendt said. In addition, unlike silk from silkworms, that from spiders apparently does not trigger the body's rejection reactions.

 On the spider-silk meshes, the team cultivated the skin cells into tissues resembling epidermis, the skin's outermost layer. 


To test spider silk's usefulness, first Wendt and her colleagues essentially milked golden silk orb-weaver spiders by stroking their silk glands and spooling up the silk fibers that came out. They next wove meshes from this silk onto steel frames.

The researchers found that human skin cells placed on these meshes could flourish, given proper nurturing with nutrients, warmth and air. They were able to cultivate the two main skin cell types, keratinocytes and fibroblasts, into tissue-like patterns resembling epidermis, the outermost layer of skin, and dermis, the layer of living tissue below the epidermis that contains blood capillaries, nerve endings, sweat glands, hair follicles and other structures.

"It was impressive to observe how human cells use spider silk," Wendt told LiveScience.
Currently, harvesting large amounts of spider silk for industrial standards is not practical. "I think in the long term, for widespread daily clinical use, synthetic silk fibers providing the same mechanical- and cell culture- properties will be needed," Wendt said. Currently, many research groups are investigating ways to grow synthetic spider silk.

The first (A) and fourth (B) day after seeding the mesh frame, the researchers found the skin cells spread from the corners into the meshes, reaching one another within a week.

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Energy From Proteins In Cow Brains

Could build better batteries, solar cells.

When we think of farming energy, we generally think of feedstocks like corn that can be processed into ethanol, or perhaps other plant life we can culture and harvest like algae. But don't underestimate the livestock; we've recently seen methane-trapping schemes that can power farms and giant cattle treadmills that turn idle dairy drones into power-producing machines. Now, a team of Stanford researchers wants to use a protein found in cow brains to make better batteries.

The concept centers on a particular protein called clathrin, which has a unique knack for assembling itself into versatile structures that foster the formation of complex molecules. Clathrin is present in every cell in the human body, but cows possess a vast wealth of it in their bovine brains that make them an ideal source for the stuff. And given the right biochemical directions, researchers think they can coax clathrin into creating better batteries and solar cells.

In cells, clathrin plays a key role in cell transport. Its tripod-like structure allows it to create a honeycomb-like lattice on the outer surface of cell walls. Atoms and molecules then attach themselves to clathrin according to the protein's will; when the right cargo is attached, the lattice collapses inward, pinching off the cell wall and delivering it's molecular payload into the cell's interior.

It's this ability to connect into structures and lure in the right molecules that makes clathrin an ideal candidate for creating battery electrodes and solar cells. Scientists can bend clathrin to their will relatively easily, coaxing it into a variety of very useful skeletal structures that they can then attach molecules to. By adding the right blend of inorganic atoms or molecules, the researchers can create electrodes, catalysts, and other battery cell building blocks.

The group has already mashed up gold and titanium dioxide into a material they call "titania" that has photocatalytic properties that allow it turn sunlight into a catalyst for water splitting. Other materials are in the works, all aimed at turning chemicals or sunlight into sweet, sweet energy. Show us an ear of corn that can do that.

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