ooo

ooo

ooo

ooo

Forget chocolate melting in your hands, try Gallium. Its a strange metal that has a melting point at 85 degrees (F). Pick up a solid piece of gallium and squeeze it in your hand for a few minutes. Soon, you’ll have a liquid puddle of metal jiggling in your hand. Scientists love to show off experiments with Gallium. Set a drop on an aluminum can and watch it slowly turn the aluminum into brittle tissue paper. Set the stuff in sulfuric acid and you’ll see it start beating like a heart. Dmitri Mendeleyev first predicted Gallium and placed it in the Period Table before it was officially discovered in 1875.
OOO
Henry Sapiecha

roman-concrete-& brickwork image www.sciencearticlesonline.com

Monuments of Imperial Rome have survived for more than a thousand years, despite repeated floods and earthquakes. Now researchers have a new clue as to why—the use of volcanic rock in their cement.

Researchers looked at Trajan’s Market and several other Imperial Roman structures to analyze the remarkable resilience of the concrete. They then reproduced a standard Imperial-age mortar—a simple mix of lime, water, and a specific kind of volcanic ash from an area now known as Pozzuoli. The recipe was taken from records of the Roman architect and engineer Vitruvius.

Scientists already knew that this particular Roman blend of concrete proved extremely tough; what they didn’t know was exactly why. After letting the test concrete toughen up over 180 and then looking at it via X-rays, the scientists here noticed dense growths of plate-like crystals made of a durable mineral known as strätlingite. Those crystals prevented the spread of microscopic cracks in parts of the mortar, which usually breaks down in modern-day cements.

They detailed their findings in the Proceedings of the National Academy of Sciences.

OOO

Henry Sapiecha

University of michigan_color_seal logo image www.sciencearticlesonline.com

ANN ARBOR–An odd, iridescent material that’s puzzled physicists for decades turns out to be an exotic state of matter that could open a new path to quantum computers and other next-generation electronics.

Physicists at the University of Michigan have discovered or confirmed several properties of the compound samarium hexaboride that raise hopes for finding the silicon of the quantum era. They say their results also close the case of how to classify the material–a mystery that has been investigated since the late 1960s.

The researchers provide the first direct evidence that samarium hexaboride, abbreviated SmB6, is a topological insulator. Topological insulators are, to physicists, an exciting class of solids that conduct electricity like a metal across their surface, but block the flow of current like rubber through their interior. They behave in this two-faced way despite that their chemical composition is the same throughout.

The U-M scientists used a technique called torque magnetometry to observe tell-tale oscillations in the material’s response to a magnetic field that reveal how electric current moves through it. Their technique also showed that the surface of samarium hexaboride holds rare Dirac electrons, particles with the potential to help researchers overcome one of the biggest hurdles in quantum computing.

These properties are particularly enticing to scientists because SmB6 is considered a strongly correlated material. Its electrons interact more closely with one another than most solids. This helps its interior maintain electricity-blocking behavior.

This deeper understanding of samarium hexaboride raises the possibility that engineers might one day route the flow of electric current in quantum computers like they do on silicon in conventional electronics, said Lu Li, assistant professor of physics in the College of Literature, Science, and the Arts and a co-author of a paper on the findings published in Science.

“Before this, no one had found Dirac electrons in a strongly correlated material,” Li said. “We thought strong correlation would hurt them, but now we know it doesn’t. While I don’t think this material is the answer, now we know that this combination of properties is possible and we can look for other candidates.”

The drawback of samarium hexaboride is that the researchers only observed these behaviors at ultracold temperatures.

Quantum computers use particles like atoms or electrons to perform processing and memory tasks. They could offer dramatic increases in computing power due to their ability to carry out scores of calculations at once. Because they could factor numbers much faster than conventional computers, they would greatly improve computer security.

In quantum computers, “qubits” stand in for the 0s and 1s of conventional computers’ binary code. While a conventional bit can be either a 0 or a 1, a qubit could be both at the same time–only until you measure it, that is. Measuring a quantum system forces it to pick one state, which eliminates its main advantage.

Dirac electrons, named after the English physicist whose equations describe their behavior, straddle the realms of classical and quantum physics, Li said. Working together with other materials, they could be capable of clumping together into a new kind of qubit that would change the properties of a material in a way that could be measured indirectly, without the qubit sensing it. The qubit could remain in both states.

While these applications are intriguing, the researchers are most enthusiastic about the fundamental science they’ve uncovered.

“In the science business you have concepts that tell you it should be this or that and when it’s two things at once, that’s a sign you have something interesting to find,” said Jim Allen, an emeritus professor of physics who studied samarium hexaboride for 30 years. “Mysteries are always intriguing to people who do curiosity-driven research.”

Allen thought for years that samarium hexaboride must be a flawed insulator that behaved like a metal at low temperatures because of defects and impurities, but he couldn’t align that with all of its other properties.

“The prediction several years ago about it being a topological insulator makes a lightbulb go off if you’re an old guy like me and you’ve been living with this stuff your whole life,” Allen said.

In 2010, Kai Sun, assistant professor of physics at U-M, led a group that first posited that SmB6 might be a topological insulator. He and Allen were also involved in seminal U-M experiments led by physics professor Cagliyan Kurdak in 2012 that showed indirectly that the hypothesis was correct.

“But the scientific community is always critical,” Sun said. “They want very strong evidence. We think this experiment finally provides direct proof of our theory.”

Henry Sapiecha

STUFF WE DID NOT KNOW WE COULD LIVE WITHOUT

Henry Sapiecha

Published on 14 May 2012

Published on 14 May 2012

Not long ago we came to you with 25 inventions that changed our way of life. Well, we’re back, but this time we’re only concerned with those inventions that no one actually intended to invent. So, from dynamite to Penicillin these are the top 25 accidental inventions that changed the world.

Henry Sapiecha


Henry Sapiecha

Published on 17 Jul 2014

From hair wigs made for dogs to billy-bob teeth and pet rocks we count 20 weird inventions that made millions of dollars

Henry Sapiecha

Published on 25 Jun 2012

10 Suppressed Inventions

Fact or fiction? Hoax or conspiracy? Here are 10 incredible inventions that some believe have been deliberately covered up.

Henry Sapiecha

world communications men image www.sciencearticlesonline.com

Telescope lenses someday might come in aerosol cans.

Scientists at Rochester Institute of Technology and the NASA Jet Propulsion Laboratory are exploring a new type of space telescope with an aperture made of swarms of particles released from a canister and controlled by a laser.

These floating lenses would be larger, cheaper and lighter than apertures on conventional space-based imaging systems like NASA’s Hubble and James Webb space telescopes, said Grover Swartzlander, associate professor at RIT’s Chester F. Carlson Center for Imaging Science and Fellow of the Optical Society of America. Swartzlander is a co-investigator on the Jet Propulsion team led by Marco Quadrelli.

NASA’s Innovative Advanced Concepts Program is funding the second phase of the “orbiting rainbows” project that attempts to combine space optics and “smart dust,” or autonomous robotic system technology. The smart dust is made of a photo-polymer, or a light-sensitive plastic, covered with a metallic coating.

“Our motivation is to make a very large aperture telescope in space and that’s typically very expensive and difficult to do,” Swartzlander said. “You don’t have to have one continuous mass telescope in order to do astronomy–it can be distributed over a wide distance. Our proposed concept could be a very cheap, easy way to achieve large coverage, something you couldn’t do with the James Webb-type of approach.”

An adaptive optical imaging sensor comprised of tiny floating mirrors could support large-scale NASA missions and lead to new technology in astrophysical imaging and remote sensing.

Swarms of smart dust forming single or multiple lenses could grow to reach tens of meters to thousands of kilometers in diameter. According to Swartzlander, the unprecedented resolution and detail might be great enough to spot clouds on exoplanets, or planets beyond our solar system.

“This is really next generation,” Swartzlander said. “It’s 20, 30 years out. We’re at the very first step.”

Previous scientists have envisioned orbiting apertures but not the control mechanism. This new concept relies upon Swartzlander’s expertise in the use of light, or photons, to manipulate micro- or nano-particles like smart dust. He developed and patented the techniques known as “optical lift,” in which light from a laser produces radiation pressure that controls the position and orientation of small objects.

In this application, radiation pressure positions the smart dust in a coherent pattern oriented toward an astronomical object. The reflective particles form a lens and channel light to a sensor, or a large array of detectors, on a satellite. Controlling the smart dust to reflect enough light to the sensor to make it work will be a technological hurdle, Swartzlander said.

Two RIT graduate students on Swartzlander’s team are working on different aspects of the project. Alexandra Artusio-Glimpse, a doctoral student in imaging science, is designing experiments in low-gravity environments to explore techniques for controlling swarms of particle and to determine the merits of using a single or multiple beams of light.

Swartzlander expects the telescope will produce speckled and grainy images. Xiaopeng Peng, a doctoral student in imaging science, is developing software algorithms for extracting information from the blurred image the sensor captures. The laser that will shape the smart dust into a lens also will measure the optical distortion caused by the imaging system. Peng will use this information to develop advanced image processing techniques to reverse the distortion and recover detailed images.

“Our goal at this point is to marry advanced computational photography with radiation-pressure control techniques to achieve a rough image,” Swartzlander said. “Then we can establish a roadmap for improving both the algorithms and the control system to achieve ‘out of this world’ images.”

Henry Sapiecha