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Science & Technology News (589)

Bringing Phase-Change Materials Closer to Computers

Category: Science & Technology
Posted: September 23, 2014 06:38AM
Author: Guest_Jim_*

Silicon is potentially one of the most important elements to certain human societies, with how reliant we are on our electronics. When silicon is eventually replaced with something better though, it will be truly amazing what may be achieved. Researchers at the University of Cambridge, the Singapore A*STAR Data Storage Institute, and the Singapore University of Technology and Design have recently made an important discovery for phase-change materials, which could be one of silicon's replacements.

Semiconductors, like silicon are used in electronics because they can be used to switch electrical signals on and off, and thereby logic devices can be built with them. Phase-change materials, however, actually switch between phases with different electrical properties, using electrical pulses. This switching can take just nanoseconds to happen, and once done, the material will persist in that phase. Naturally this gives PCMs a potential use for storing data, as non-volatile memory, but it could also be used to perform logic operations. Such in-memory logic devices have been demonstrated, but they have been slower than silicon devices and lack stability. However, the researchers have discovered that by reversing the process that had been used, starting from the conducting, crystalline phase and going to the insulating, amorphous phase, the devices could be faster and more stable.

Combining memory and logic operations into a single device could have dramatic impacts on computing, by conserving space and improving speed. Also, as PCM memory devices are non-volatile, there would be energy savings compared to DRAM, which must refresh the data it stores, or risk losing it.

Source: University of Cambridge



Bringing Gesture Control to Smartphones

Category: Science & Technology
Posted: September 22, 2014 03:30PM
Author: Guest_Jim_*

According to science fiction, it is cool and futuristic to be able to control devices by waving one's hands. Some technologies already exist to let us do just that, and many of these rely on a device's camera, which works, but is not necessarily the ideal solution. Researchers at the University of Washington have developed a way to use a cellphone's data transmissions to track movement in the area around it for input.

For any number of reasons, our phones broadcast wireless signals that penetrate many materials, including our bodies, very well, but not perfectly. Some of the transmitted signals will be reflected back to the device. With multiple, low-power receivers in a smartphone, the reflection could be picked up and analyzed to track position and movement, and the researchers have aptly named this project SideSwipe.

Compared to camera-based systems, SideSwipe could cut down on battery use, as the data processing involved is much simpler than the video processing cameras require. Also the penetrating nature of wireless transmissions allows SideSwipe to function even when the smartphone would is in a user's pocket or bag.

Source: University of Washington



New Touch Sensor gives Robots Great Dexterity

Category: Science & Technology
Posted: September 22, 2014 09:22AM
Author: Guest_Jim_*

There are some senses we cannot imagine being without, and touch is definitely one of them. Robots however have only had limited experience with the sense of touch, and they would have as much use for it as we do. Researchers at MIT have recently created a new touch sensor that can give robots touch with impressive accuracy in real time.

The new sensor is actually based on an old design called GelSight, which uses light to measure touch. The sensor consists of a plastic cube with metallic paint on one side, along with multiple lights and detectors. These lights, each a different color, shine through the cube, bouncing around and reflecting off of the paint, until eventually returning to the light detectors. These detectors measure the intensity of the light and feed that data to a computer-vision algorithm that uses it to reconstruct the surface of the cube. The original GelSight sensors could resolve deformations on the micrometer scale, while this version works on the millimeter scale. That is still more sensitive than our fingers though and the loss in resolution does allow the sensor to be smaller and for the processing to be done in real time.

The researchers have already tested a robot with a single one of these sensors by having it plug a USB cable into a plug (something some people even have trouble with). With luck, we may see this prototype developed into a practical device before long.

 

 

Source: MIT



Another Potential Silicon Replacement has been Discovered

Category: Science & Technology
Posted: September 22, 2014 06:09AM
Author: Guest_Jim_*

As we approach the limits of silicon circuitry, more and more replacements are appearing to claim the element's throne. Hopefully silicon's reign will last long enough for a clear successor to be found. Researchers at Harvard though have discovered a new material that could be that successor.

This new material is what is called a correlated oxide and uses quantum mechanics to challenge silicon. The base material is samarium nickelate, but by doping it with hydrogen or lithium, the researchers were able to manipulate its band gap. The band gap is a very important characteristic of many materials as it determines the energy difference between conducting and non-conducting electrons. Silicon transistors require the ratio between conducting and non-conducting, or on/off states, to be 104. Previous attempts with correlated oxides have only had an on/off ratio of 10 or 100, but the Harvard researchers were able to achieve a ratio greater than 105, putting it near state-of-the-art silicon transistors. This ratio is present when the material is at room temperature, or even hundreds of degrees above it.

One would expect that a material to potentially replace silicon would come from a lab investigating such replacements. This discovery actually came out of a fuel cell lab though, where the researcher's experience with thin films and ionic transport was used to create the correlated oxide.

Source: Harvard University



NVIDIA Uses Maxwell GPU Architecture to Prove Apollo 11 Moon Landing Was Legit

Category: Science & Technology
Posted: September 20, 2014 08:15AM
Author: ClayMeow


NVIDIA's debut of the GTX 900 Series graphics cards issued in the first wave of Maxwell-based GPUs; an architecture that is pretty damn impressive. Among its many features (such as Dynamic Super Resolution), NVIDIA "designed Maxwell to solve some of the most complex lighting and graphics challenges in visual computing." NVIDIA's game demo team decided to test the capabilities of its new technology in a rather unique way, recreating the moon landing scene in Unreal Engine 4 using one of Maxwell's key technologies – Voxel-Based Global Illumination, or VXGI.

VXGI is a new and improved representation of the way light bounces from one object to another in real time, by breaking a scene's geometry into many thousands of tiny boxes called voxels (essentially a pixel in 3D). Maxwell accelerates the creation of these voxels using a technology called "multi-projection", which lets the GPU process the geometry just once for each box's six sides. So how did the demo team use this technology to prove the legitimacy of the moon landing?

Conspiracy theorists have argued for decades that Buzz Aldrin's suit must have been lit from something other than the sun, since the sun was behind the lunar module. The only explanation was that it was an auxiliary light source... in a studio. The photo was just too perfect. After NVIDIA's demo team "researched the rivets on the lunar lander, identified the properties of the dust coating the moon's surface, and measured the reflectivity of the material used in the astronauts' space suits," NVIDIA got to work on recreating the scene. Not only was the demo team able to reproduce how the light illuminated Aldrin, proving there was no artificial light source, it was also able to prove that the reason there were no stars in the photo was simply due to the exposure level of the camera.

NVIDIA's demonstration is quite the fascinating and unique use of a technology we typically think as only applicable to gaming or rendering. So now that one of the top conspiracy theories has been debunked, what's next for the green team? The Kennedy Assassination?

Source: Press Release and NVIDIA Blog




Supermassive Black Hole Found in Dwarf Galaxy

Category: Science & Technology
Posted: September 19, 2014 02:07PM
Author: Guest_Jim_*

They say great things can come in small packages, and it appears that may be true, if you can think of a dwarf galaxy as 'small.' Researchers at the University of Utah have discovered that a dwarf galaxy may have at its center a supermassive black hole many times larger than the one at the center of our own Milky Way.

M60-UCD1 is a so-called ultracompact dwarf galaxy orbiting M60, which is one of the larger galaxies in our area. The researchers had previously examined the dwarf galaxy, noting the rate at which it was emitting X-rays. The rate matches that of gas falling into the supermassive black holes of other, much larger galaxies. Using the Gemini North telescope on Hawaii's Mauna Kea, the researchers determined that M60-UCD1 may have at its core a supermassive black hole weighing it at 21 million solar masses. With a total mass of 140 million solar masses, that black hole would make up 15% of the galaxy's mass. For comparison, the black hole at the center of the Milky Way comes in at 4 million solar masses, but our galaxy weighs 50 billion solar masses (50,000 million, to be clear).

The obvious question is how could a dwarf galaxy have such a large black hole at its core? The researchers suggest that the dwarf galaxy is possibly what remains of a once larger galaxy, where a supermassive black hole is more expected. When it passed by another galaxy, likely M60, most of the gas and stars were stripped off, leaving what looks like a dwarf galaxy behind. If this is accurate, then other dwarf galaxies may also house similarly large supermassive black holes.

Source: University of Utah



Future Spacesuits may be Skin Tight

Category: Science & Technology
Posted: September 19, 2014 09:18AM
Author: Guest_Jim_*

Many children once envisioned that when they grew up, their work attire would be a spacesuit. While it is easy to say that spacesuits are cool, future spacesuits may have a very different look to them in the future. Researchers at MIT are working on a design that could see modern bulky spacesuits replaced with suits that are effectively a second skin.

Spacesuits are really just small spacecraft with life support systems to keep the occupant warm and at a livable pressure. Modern designs achieve that pressure using gases, but the design the researchers are working on would rely on mechanical pressure instead. That pressure would be delivered by coils of a shape-memory alloy. These materials are special metals that can learn a specific shape that they will return to, when heated to a certain temperature. Below that temperature, the alloy is pliable like a paperclip. The idea is to incorporate these coils into the spacesuit, which will be flexible enough for an astronaut to put on, and once on the alloys will be heated to return to their learned shape, which will be smaller, pulling the suit onto the person.

While tests show that such a spacesuit would be able to apply the needed amount of pressure to a body, it does have the problem of requiring temperatures that would eventually cook the astronaut, unless a locking mechanism can be developed. Given the reduction in weight and potential increase in mobility though, you can bet that the flaws will be worked out eventually.

Source: MIT



Experiment Suggests Alternative View of Quantum Mechanics

Category: Science & Technology
Posted: September 19, 2014 06:50AM
Author: Guest_Jim_*

According to quantum mechanics, the quanta that make up the Universe exist in a wave-particle duality. The interpretation that has been traditionally used of this is the Copenhagen interpretation, which treats all particles as waves, and that measuring the wave causes it to collapse down to a particle. This is not the only interpretation though, and one that some of the founders of quantum mechanics is getting new life breathed into it, thanks to a recent experiment at MIT.

Pilot-wave theory presents a very different interpretation of the quantum world as instead of treating particles as the result of observing waves, it keeps them as particles. These particles are on top of some kind of wave though, which influence the particle's trajectory and that explains the wavelike behavior of the particles. The experiment the researchers did involved vibrating a bath of fluid at a rate just below what would cause waves to appear on the surface. A drop of the fluid was then dropped onto the surface, causing waves to radiate from the impact. That droplet was then propelled by those waves, similar to how the pilot-waves would influence the movement of a particle.

As the researchers do point out, there are many quantitatively and qualitative differences between the quantum theory and fluid experiment, which prevent it from being actual evidence of the theory. However, they could be philosophically similar enough to suggest that pilot-wave theory be reexamined with the new tools of chaos theory and the results of this experiment. Perhaps in the future it or another interpretation may become the new standard.

Source: MIT



New Water-Based Nuclear Battery Created

Category: Science & Technology
Posted: September 18, 2014 02:00PM
Author: Guest_Jim_*

In the quest for a superior battery, researchers at the University of Missouri-Columbia have developed a new long-lasting battery. This battery design is a bit different from what you will find in your devices though, as it is a nuclear battery.

Nuclear materials have seen various energy uses over the years, from large-scale power plants to small thermoelectric systems, like those in some space missions. This battery operates in a different way though, by using betavoltaics instead of any use of thermal energy. In betavoltaics, the nuclear material, in this case strontium-90, emits beta particles into a water-based solution, which increases its electrochemical energy. A titanium dioxide electrode coated in platinum then collects and converts that energy into useable electricity.

With the battery's long life and efficiency, it could see use in automobiles and in space flight. It is likely worth noting that controlled nuclear technologies need not be dangerous, such as those that are used in fire detectors and emergency exit signs.

Source: University of Missouri-Columbia



Tuning a Potential Optoelectronic Chip Light Source

Category: Science & Technology
Posted: September 18, 2014 10:15AM
Author: Guest_Jim_*

Some day we may see parts of our computer using photons instead of electrons to carry information. Photons can carry information faster and are more efficient at doing so, but the necessary components, especially emitters, are difficult to make. Researchers at MIT have recently found that one material that could work as a light source can be tuned to produce specific frequencies.

Monolayers of molybdenum disulfide (MoS2) have very good optical properties that could be integrated into optoelectronic chips. These good properties come from, in part, the direct band gap of the material, which makes it easier for excited electrons to drop in energy, emitting a photon in the process. Normally MoS2 is used just as a single layer, but the MIT researchers worked with it in pairs of layers. The presence of the second layer did reduce the intensity of the emitted photons, but it also interfered with where the excited electrons would drop to. Instead of dropping back to the same MoS2 layer, the electrons could drop into the other layer, releasing a photon of a different frequency. The specific frequency could be tuned by controlling the relative angle between the two layers.

With the ability to tune the frequencies of the photons, optoelectronic chips could be designed to carry information along multiple frequencies, like what is done currently to increase bandwidth. Naturally MoS2 does have competition as a light source, but being a thin film keeps it simple and cheap to produce, unlike the 3D, complex systems also being investigated.

Source: MIT



Bringing Lithium-Sulfur Batteries Closer to Reality

Category: Science & Technology
Posted: September 18, 2014 07:28AM
Author: Guest_Jim_*

Lithium-ion batteries are something of a standard technology now, with them being used in everything from electric cars to cellphones. While the technology has been serving us well for some time, we are approaching its limits and have to look for a replacement. As reported by the American Chemical society, one of these replacements got a big boost recently.

One of the ways to improve a battery is to use better electrodes in it, and for a while it has been known that sulfur would be better for lithium batteries than the current metal oxides. The problem is that lithium sulfur compounds have a tendency to escape, and take what energy they have with them. To address this, researchers have made small, hollow shells of carbon to hold the lithium sulfur compounds, and coated the shells with a polymer.

When tested, the energy storage capacity was 630 milliampere hours per gram, compared to the 200 mAh/g of modern lithium-ion batteries, and that capacity persisted over 600 charging cycles. Theoretically a lithium-sulfur battery could store five to eight times more energy than modern batteries.

Source: American Chemical Society



Entangled Photon Triplets Detected

Category: Science & Technology
Posted: September 17, 2014 04:06PM
Author: Guest_Jim_*

Quantum mechanics allows for some odd things, such as particles being so strongly coupled, that information about one determines the information about the others. This phenomenon, entanglement, is one that many hope to exploit for quantum computers, but is not particularly easy to work with. Researchers at the University of Waterloo, using single-photon detectors developed by NIST, have recently succeeded in creating entangled photon triplets, which could prove especially useful in future quantum technologies.

To create the triplets the researchers started with a blue photon that was polarized both vertically and horizontally, thanks to superposition, another quantum mechanical phenomenon, and sent it through a special crystal. This crystal converted the single blue photon into two red photons that have the same polarization. One of these daughter photons then entered another special crystal that converted it into two infrared granddaughter photons, which just happen to be at a frequency commonly used in telecommunications. Thus they could actually be transmitted along a fiber optic cable.

As all of these photons have the same polarization, they form an entangled triplet, but this process, called cascaded down-conversion, is hardly efficient. The first stage only works one in a billion times, and the second is one in a million. That is where the NIST single-photon detectors came into play, as they drastically simplified the work of finding the number of triplets, confirming that the system worked at all. Eventually, as the process is improved, the researchers hope to go past triplets and generate four or more entangled photons at a time.

Source: NIST



Using Nanoribbons to Melt Ice

Category: Science & Technology
Posted: September 17, 2014 11:11AM
Author: Guest_Jim_*

Ice can be quite a problem, even when it is not causing us to slip and fall. When it builds up on radar domes, for example, it can actually interfere with their performance, which is why researchers at Rice University developed a new deicing system. Now they have refined the technology and succeeded in making it optically and radio-frequency transparent.

Originally the researchers created a paint containing graphene nanoribbons, made by splitting carbon nanotubes, mixed with polyurethane. By applying a voltage to the paint, the nanoribbons heat up and melt the ice that may have collected on the paint. What the researchers originally created though had the problem of heating up when exposed to extremely high RF, to the point that it burned up. To correct that, the researchers have made the films in the paint more consistent and coated the nanoribbons in the polyurethane, to prevent them from forming active networks. These changes preserved the films' transparency, so the researchers tried coating a glass slides with it, and then iced them. Even at temperatures of -20 ºC, the ice melted when a voltage was applied.

Naturally this deicing system will still be of use with radar systems, which would otherwise rely on larger, less efficient metal oxide systems, but thanks to being optically transparent, it could also be integrated into windshields and even skyscraper windows. In these situations the RF transparency could also prove useful, as cell transmissions and Wi-Fi would not be blocked.

Source: Rice University



Manipulating Liquid Metals by Controlling Surface Tension

Category: Science & Technology
Posted: September 17, 2014 06:34AM
Author: Guest_Jim_*

Liquid metals have been fascinating people for many years, and now researchers at North Carolina State University have found an interesting way to control them. Like other liquids, liquid metals have a surface tension, which is what the researchers have now learned to manipulate, using voltages under one volt.

For their study, the researchers worked with a liquid metal alloy of gallium and indium, which normally has a surface tension of 500 millinewtons per meter. That is pretty high and causes the metal to bead up. By applying a positive charge of less than one volt to it though, an oxide layer will form on the surface and act as a surfactant. The result is that the surface tension drops from 500 mN/meter to just 2 mN/meter, causing the liquid metal to spread out as a result of gravity. By reversing the charge of the voltage, the oxide layer is removed and the surface tension restored. The surface tension can be tuned by applying voltages between the two extremes.

Such control could be used to affect the movement of the liquid, as well as the shape, allowing circuits to be made and broken. Microelectromechanical systems, microfluidic channels, and photonic and optical devices could all be potentially applications for this discovery.

 

 

Source: North Carolina State University



Batteries Behave Differently than Expected

Category: Science & Technology
Posted: September 16, 2014 03:14PM
Author: Guest_Jim_*

Everyone with a mobile device, whether it is a laptop or smartphone, wants it to be charged as quickly as possible, so we can get back to using it. Charging and discharging a battery too quickly can damage it though, by the rapid swelling of the electrodes. At least that is what we have all believed for some time now, but researchers at SLAC have recently discovered that may not be the case.

As part of the normal operations of batteries, ions will move in and out of the electrodes during charging and discharging cycles. If not all of the nanoparticles in the electrodes participate in the process, there is a risk of uneven swelling, which damages the electrodes. The SLAC researchers used many small coin cell, lithium-ion batteries that they charged with different levels of currents and over different amounts of time. They then took apart the cells and washed them, to stop the charge/discharge process, and cut the electrodes into thin slices for analysis. By looking at thousands of electrode nanoparticles at a time, the researchers discovered that only a small percentage of the nanoparticles were involved when charging, even when done very quickly. When the discharging rate increased however, more and more nanoparticles got involved, achieving a more uniform, and therefore less damaging mode.

This research would seem to indicate that lithium ion batteries could be discharged more quickly than they are currently, without necessarily sacrificing the life of the battery. Also it may be possible to tweak electrodes for better charging rates. The next step is to look at how the battery electrodes survive through hundreds or thousands of cycles, like what we put our devices through.

Source: SLAC National Accelerator Laboratory



Replicating Squid Skin to Create a Color Display

Category: Science & Technology
Posted: September 16, 2014 10:38AM
Author: Guest_Jim_*

For thousands of years, humanity has been working to uncover the mysteries of Nature, and we are still at it. Recently special attention has been given to the skin of cephalopods, which can change in color as well as 'see' color. Researchers at Rice University have now recreated the color changing aspect of the skin to create a color display that matches the vividness of modern displays.

The pixels in the new display are comprised of several hundred aluminum nanorods, and the color of each pixel is determined by their length and spacing. Electron-beam deposition was used to create the precise arrangement of nanorods, which ensure that only one color is produced by the aluminum. Previous attempts to use aluminum nanoparticles like this resulted in more muted colors, as a wider range of frequencies were created and mixed together.

Among the potential uses of these arrays is replacing the dyes in LCD displays. Dyes can wear out over time from prolonged light exposure, but the physics involved with the nanorods will never fade. Also the light produced by the nanorods is naturally polarized, which means that one less polarizer would be needed in a display using them.

Source: Rice University



Cheetah Robot Jumps and Runs Free

Category: Science & Technology
Posted: September 16, 2014 06:04AM
Author: Guest_Jim_*

Everyday many of us walk and run without much thought, because our brains and bodies know what to do. Robots however are still learning these actions and researchers at MIT recently constructed and programmed a robot to run and even leap over objects in its path. The robot is designed to emulate the cheetah, but does not yet match its speed, having only sprinted at 10 MPH.

To achieve this speed, each leg of the robotic cheetah follows a bounding algorithm that determines the amount of force that is applied to the ground. To determine exactly how much force is applied, the researchers looked to sprinters who extend their stride by pushing against the ground hard enough, to extend their airtime. Such a force-based approach actually makes it easier for the robot to navigate rough terrain and does not require force sensors on the feet. Also by simply increasing the force applied to the ground, the robot can leap over obstacles in its path.

One thing about this robot that sets it apart from many other is that it is all electric, which counters the belief some have that only a loud gasoline engine can provide the necessary power. The next goal the researchers have is to actually get the robot galloping, which should be easy to do from its current, bounding gait.

 

 

Source: MIT



Sound Used to Control Artificial Atom

Category: Science & Technology
Posted: September 15, 2014 02:08PM
Author: Guest_Jim_*

In the 1960s we learned about the sound of silence and now we are learning what the sound of an atom is. An artificial atom more specifically, which releases its vibrational energy is released as a kind of quantum particle. Researchers at Chalmers University of Technology have recently built a device to couple acoustic waves with the artificial atom, an achievement that could lead to some very interesting effects.

Artificial atoms are actually circuits made of a superconducting material, but they behave like atoms with the ability to be charged with energy, and emit it as a particle. Normal atoms emit this energy as light, but the researchers designed the artificial atom to actually emit and absorb acoustic energy. This energy would be comprised of quantum particles representing the weakest detectable sound. The frequency used was 4.8 GHz, which is close to microwave frequencies for light, but in music would be roughly D28, or 20 octaves above the highest note on a grand piano.

The value of coupling an artificial atom to sound is that sound is easier to control; with how much slower it is than light. This slow speed also translates to a very small wavelength that can actually be smaller than the atom, unlike light waves which are larger. That smaller relative size makes the properties of the atom easier to control, which could prove useful in future quantum technologies.

Source: Chalmers University of Technology



Finding Graphene's Friction Properties

Category: Science & Technology
Posted: September 15, 2014 09:14AM
Author: Guest_Jim_*

Friction is an inescapable phenomenon of the Universe, for better or worse, and ways to control it are always important. Adding fluorine to some carbon-based materials, like Teflon, is the key to making some non-stick materials, so it made sense to expect graphene to also become non-stick, by adding fluorine atoms. As researchers at the University of Pennsylvania discovered though, the result of that added fluorine atoms was actually increased friction, not decreased.

The reason for investigating how to make graphene, an atom-thick sheet of carbon, non-stick is to use it as a coating to protect surfaces from normal wear and tear. As graphene is so thin and exceptionally strong, its use as a coating makes sense, and making it non-stick would make it even better. The Pennsylvania researchers were not the only group to create fluorinated graphene, and both groups reported the increase in friction, but the other group attributed it to an increase in stiffness. The Pennsylvania researchers were not satisfied with this explanation though, and started examining and modelling the energy levels of the material. On the macroscale, energy levels do not impact friction, but at the scale graphene exists, energy levels can be just as powerful as physical levels.

What they determined was that the fluorine atoms were introducing peaks to the material's electronic energy levels, making it very rough compared to pure graphene. All is not lost though, as a coating of high-friction graphene could have a use, and this research improves our understanding of graphene's surface properties.

Source: University of Pennsylvania



Using Graphene to Block Corrosion

Category: Science & Technology
Posted: September 15, 2014 07:32AM
Author: Guest_Jim_*

Graphene has a long list of special properties, including great conductivity, flexibility, and mechanical strength. Also on the list is the curios ability to block gases and liquids, except for water. Researchers at the University of Manchester, however, have discovered a way to make graphene oxide completely impermeable, which would have numerous implications.

The reason stacks of graphene sheets let water through has to do with how the water molecules interact with the sheets, causing capillaries to form that the molecules can slip through, and sometimes bring other molecules with them. This has obvious uses for water purification, but it could also be used to protect surfaces from corrosion, weather elements, and more, if only water could also be blocked. The Manchester researchers found that simple chemical processes could actually be used to close those capillaries in graphene oxide films, making them stronger and impermeable.

Demonstrating what is possible with this the researchers covered copper plates with their graphene paint, and showed that they could store strongly corrosive acids. Potentially it could also find use in electronics, shipbuilding, the nuclear industry, and even for improving the shelf life of medicines.

Source: University of Manchester



Approaching the Quantum Mechanical Defeat of Classical Computers

Category: Science & Technology
Posted: September 12, 2014 02:02PM
Author: Guest_Jim_*

For years now, researchers have been working on quantum computers that, thanks to quantum mechanics, will be able to run algorithms no classical computer could complete, in a reasonable amount of time. So far though, no quantum computer has been built that actually surpasses its modern electronic counterparts. Thanks to researchers at the University of Bristol, University of Queensland, and Imperial College London though, that defeat of classic computers may be sooner than ever before.

The key to this defeat of classical computers is to successfully run a quantum algorithm they cannot. Recently MIT researchers developed an algorithm known as Boson Sampling, which uses single photons to sample an exponentially large probability distribution. A classical computer would find the same task to be extremely difficult. The catch for quantum computing is that producing the needed number of single photons is also difficult.

What the team of researchers recently discovered is that two-photon sources could be chained together to generate more of the single photons, using standard probabilistic methods. With that done, the researchers just needed to prove that this new photon source can solve the Boson Sampling algorithm, and with that, the last experimental hurdle for demonstrating the power of quantum computers should be overcome.

Source: University of Bristol



Possibly Improving the Efficiency of Electronics with Odd Electron Movement

Category: Science & Technology
Posted: September 12, 2014 09:36AM
Author: Guest_Jim_*

When multiple fields in science collide, crazy things can happen. Researchers at MIT and the University of Manchester have recently discovered a unique behavior of electrons in a superlattice of graphene and hexagonal boron nitride, which connects materials science, particle physics, relativity, and topology. What was actually observed though has, "no known analog in particle physics."

When electrons are exposed to an electric field, they will try to move and take the path of least resistance, which is in the direction of the field. This is true of traditional conductors and of graphene, which has the unique property of conducting electrons as though they were massless particles. When a layer of graphene is atop of layer of boron nitride however, the researchers observed the electrons actually moving in a perpendicular direction to the field. Normally a magnetic field would be required to alter the direction of an electrical current like this.

To make this phenomenon even weirder, the researchers also discovered that two electrical currents could flow perpendicular to the field, creating a "neutral, chargeless current," as the charges cancel each other out. This could possibly be exploited to improve the efficiency of computers as such a chargeless current would not lose much energy to heat. However, the researchers do point out that other parts of the system may offset those efficiency gains, so more work is required to determine how useful this would be. Even without that answer though, this is still a discovery that will impact our understanding of how the Universe works.

Source: MIT



Phosphorus a Potential 2D Semiconductor

Category: Science & Technology
Posted: September 12, 2014 06:20AM
Author: Guest_Jim_*

Since graphene was first discovered, there has been a rush to find other two-dimensional materials, and discover their properties. The hope is to find one with properties that can be put to use in future technologies. Researchers at Rice University have recently discovered that 2D phosphorus may be an ideal semiconductor for advanced computers.

Like graphene, 2D phosphorus has a hexagonal lattice, but instead of being a flat sheet, alternating atoms jut out above the plane. This results in a greater variation to any defects in the material, which results in a deeper bandgap and decreased performance for many other materials. In this case though, because it is all phosphorus, the defects actually do not negatively impact the material's electrical properties. This makes it a superior semiconductor to the 3D silicon currently used in electronics, as grain boundaries and point defects do not affect its properties.

Obviously one potential application of 2D phosphorus is future computer chip, but it could see use in many of places. One example would be for solar cells as its bandgap should respond well to the spectrum of sunlight.

Source: Rice University



500 GHz Photon Switch Developed

Category: Science & Technology
Posted: September 11, 2014 02:02PM
Author: Guest_Jim_*

More and more people want optics used to carry data across the nation and to their homes. This makes sense as photons can travel much faster and more efficiently than electrons, but they are still not as fast at carrying information as they could be. Researchers at the University of California, San Diego though have created a new photon switch that operates more than ten times faster than anything previously reported.

To achieve that amazing switching speed of 500 GHz, the researchers had to identify the ideal fiber for carrying the photons, develop a new means of measuring the fiber core, and determine the fewest number of photons needed to trigger the switch. The ideal material turned out to be silica fibers, as it has very little optical loss and kilometer-scale interaction lengths, but that is only half the work. The other half required analyzing the fiber core to profile its fluctuations over a great distance and with sub-nanometer precision. The method they developed is so precise that if a fly were land on the fiber miles away, the distortion to the fiber core would be measurable.

The precision of the fiber is matched by the efficiency of the 500 GHz switching. The researchers found that 2.5 picosecond pulses containing just three photons would be enough to control the light pulses, at that switching speed.

Source: University of California, San Diego



Controlling Crystals of Sandwiched 2D Materials

Category: Science & Technology
Posted: September 11, 2014 10:10AM
Author: Guest_Jim_*

On its own, bread is nice, and on their own, cold cuts, hamburgers, sausages, peanut butter and jelly are nice, but combining them can give us something even better. (They can also make me hungry as I write about them.) Just as this is true for foods, advanced materials can also become more than what they were before when sandwiched together. Researchers at the University of Manchester have recently found that by manipulating a sandwich of graphene and white graphene, it is possible to tune the properties of the resulting crystal.

Graphene is an atom-thick sheet of carbon that is extraordinarily conductive, while so-called white graphene, hexagonal boron nitride (hBN) is actually a semiconductor. Some are hopeful that combinations of these two materials could result in new materials with superior properties to both, which could then be used in electronics. What the Manchester researchers have found is that when hBN is sandwiched between layers of graphene, the properties of the resulting hetrostructure can be controlled by altering the alignment of the layers.

With careful alignment of the graphene layers, conservation of energy and momentum can be achieved, which could allow for devices to operate with ultra-high frequencies. The next step, according to the researchers, is for someone to find a way to produce these multilayer materials using growth methods, instead of mechanical transfer.

Source: University of Manchester



Flexible Display with Graphene Components Created

Category: Science & Technology
Posted: September 11, 2014 06:15AM
Author: Guest_Jim_*

Graphene has often been described as a material that could revolutionize many technologies, but so far it has yet to escape the lab and enter consumer products. Thanks to a partnership between the University of Cambridge and Plastic Logic though, that may change sooner than ever. Together the two organizations have created a flexible display that uses graphene for its electrodes.

Graphene is an atom-thick sheet of carbon atoms that has extraordinary electrical and physical properties, including being strong, flexible, transparent, and highly conductive. All of these contribute to why we want to see it used in our devices. The prototype display uses solution-processed graphene electrodes to replace the sputtered metal electrodes normally found in Plastic Logic's devices. This allows the display to be more flexible than if indium tin oxide were used, and more transparent than metal films would allow. It was also created at temperatures below 100 ºC.

The display itself may not be impressive beyond its flexibility and use of graphene, as it is only150 ppi and monochrome, like ereader displays. However the researchers are working to achieve full color and video by incorporating LCD or and OLED technologies.

 

 

Source: Rice University



Graphene Drum Created with Quantum Computing Potential

Category: Science & Technology
Posted: September 10, 2014 02:33PM
Author: Guest_Jim_*

Drums are an important part of any orchestra and each one fills a specific role, based on its mechanical properties. Thanks to researchers at the Delft University of Technology, drums, though not of the musical kind, could see an interesting use in future quantum computers.

The drum in question is a multilayer sheet of graphene covering a hole in a silicon chip just four microns wide. What makes the drum special is that next to it is a superconducting microwave cavity. This cavity produces microwave photons that can move between the two structures and actually beat the drum. This beating is possible because photons do carry a small amount of momentum, despite being massless. In the macroscopic world, this momentum does not have much of an impact, but it is enough to move the very light sheet of graphene. Provided the movement is greater than 17 femtometers, (approximately ten thousand times smaller than the diameter of an atom) it can be measured by the interference of the photons reflecting off of it.

This is the first time a mechanical resonator has been shown to be coupled to a superconducting microwave cavity, and such a setup could have many uses, such as amplifying microwave signals and even storing microwave signals for up to 10 ms. It could also be used as RAM for quantum computers, by having the drum enter a superposition with its beat, being both up and down at the same time.

Source: Institute of Physics



Taping UHF for Broadband Wireless Data

Category: Science & Technology
Posted: September 10, 2014 10:48AM
Author: Guest_Jim_*

One of the consequences of the recent switch over from analog to digital of broadcast television was an opening up of spectrum blocks. Some hope to use these now available frequencies to serve wireless data over large areas, but typically increased range means decreased speed. By applying some modern wireless transmission methods, Rice University researchers hope to reach an acceptable balance.

One of the technologies being employed is MIMO or multiple-input, multiple-output, which uses multiple antennae to increase data rates without using for channels or power. This is a somewhat standard technology now that many devices now use. It is not enough to reach the needed balance though, which is why the Rice researchers developed the first open-source multiuser MIMO system. Instead of using the technology to provide a single user a better experience on a single channel, this multiuser system would serve multiple users all on the same channel.

The researchers have already tested their multiuser MIMO UHF system against 2.4 GHz and 5.8 GHz WiFi in both indoor and outdoor environments. The new system performed well with low-overhead wireless access and high spectral efficiency.

Source: Rice University



Using Social Media to Support Weight Loss

Category: Science & Technology
Posted: September 10, 2014 08:35AM
Author: Guest_Jim_*

Weight is a problem for many people, and for those that reach the obese levels it can also become a health hazard with increased risk for multiple illnesses. To address the issue, researchers have been devising many new strategies, and those at Imperial College London are suggesting that social media be leveraged to help people lose weight.

Instead of generating new data through new experiments, the researchers analyzed 12 studies from the US, Europe, east Asia, and Australia. All of these studies were examining how social networking could be used to encourage and support weight loss, and combined had 1884 participants. The ICL researchers compiled the data and found that those who used the social networking services saw a BMI decrease of 0.64. While that value is only modest, it is significant and is definitely an encouraging sign of what could be accomplished.

The idea behind social media for weight loss is to build a network of clinicians and peers that support efforts to lose weight. While you do potentially have reduced costs, thanks to less travel and more people served at once, there are potential privacy issues that will likely have to be addressed. Still, this shows that there is another tool that can be used to fight obesity and the associated illnesses.

Source: Imperial College London



New Alloy that Strengthens as it Cools

Category: Science & Technology
Posted: September 9, 2014 04:24PM
Author: Guest_Jim_*

Thousands of years ago, humanity discovered how to create metallic alloys, which can often have properties superior to the original materials used. One example would be bronze, which is stronger than the copper that it is largely comprised of. Now researchers at Berkeley Lab and ORNL have discovered a new high-entropy alloy that could be of special use in extremely cold situations.

Typically alloys are composed of a few elements, with one representing the primary component, such as copper in bronze and iron in steel. High-entropy alloys however are made of multiple elements, and none is more dominant than another, and it has been theorized that such a material would have special properties. The Berkeley and ORNL researchers have put that to the test with CrMnFeCoNi (chromium, manganese, iron, cobalt, and nickel) and were actually surprised by the results. The alloy's tensile strength and fracture toughness are among some of the highest values ever recorded, and actually improve at cryogenic temperatures. The researchers believe it is because of a phenomenon called 'nano-twinning' which involves deformations in one crystalline region to be mirrored in another. This causes continuous strain hardening, which protects against premature failing.

This unique improvement at cryogenic temperature makes the alloy of great interest for making storage tanks for liquefied natural gas, hydrogen, and oxygen. These special mechanical properties have not been optimized yet, so CrMnFeCoNi may improve as research continues.

Source: Berkeley Lab



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