Science & Technology News (204)
Posted: December 13, 2013 06:04AM
Everybody is familiar with magnets and there is a good chance many of us are also familiar with what happens when a magnet breaks; you get two magnets. The reason breaking a magnet gives you two is that the magnet itself is made up of many smaller magnets, but when you get down to the size of atoms, magnetism is not as well understood. Researchers at the London Center for Nanotechnology have recently made a discovery about the directionality of magnetic atoms that could have many impacts.
For the magnets we deal with on a daily basis, the directionality or anisotropy or the magnet is determined by its shape. As atoms are incredibly small, it is hard to characterize a shape for them, which makes it hard to manipulate their magnetic anisotropy. At least that is what had been believed, but the LCN researchers have discovered the Kondo effect can also impact this property. The Kondo effect comes from a magnetic atom and metal coupling, and the researchers discovered the relationship measuring the anisotropy with a scanning tunneling microscope of cobalt atoms between a copper surface and atomically thin sheet of copper nitride.
Being able to affect the magnetic anisotropy of an atom could be very powerful, especially as the Kondo effect can be controlled and tuned electrically. This could lead to new kinds of magnets that rival the strength of rare earth magnets, without the rare and expensive metals.
Source: London Center for Nanotechnology
Posted: December 12, 2013 05:00PM
Changing shape can be a very useful ability in many situations, but can also be hard to achieve. After all, most materials will only deform when a force is applied to them, which means a mechanism is needed to apply that force. Researchers at Rice University though have created a composite material that can change its shape when heated.
The composite is made of two layers. One layer is a simple but important polystyrene, and the other is a liquid crystal elastomer (LCE). The elastomer is made of cross-linked polymers that align to an axis called the nematic director. When heated, the LCE will expand or contact along that axis, but because of the polystyrene, the expanding material cannot stay flat, but bends, wrinkles, or folds the entire material. By controlling the geometry of the polystyrene and the temperature it was applied at, the researchers found they could control the shapes the composite will take.
The ability to have a material change shape based on environmental conditions has potential applications in optics, biology, and medicine. For example, scaffolds and substrates for cells to grow on could be designed to react to different stimuli, and expand or contract as needed.
Source: Rice University
Posted: December 12, 2013 08:07AM
While I doubt that physical controls such as keyboards and mice will ever go away, motion controls are growing more common and popular. The many motion control systems currently available use a variety of technologies, but most if not all rely on being able to see the user. That is not the case with WiTrack, a new system developed by MIT researchers as it can capture your motion through walls.
This is not MIT's first venture into motion tracking through walls, but the previous attempt, called Wi-Vi, relies on Wi-Fi signals. The new WiTrack system instead uses lower energy signals that allow for much higher accuracy. Specifically, it is able to determine a person's position to within ten to twenty centimeters. The hardware achieving this includes one transmitter and three receivers, while the software uses algorithms capable of filtering out echoes and identifying when the pulse of radio waves was emitted. Combined this is able to not only follow you behind a wall but also track gestures, so you can turn lights off in another room, just by pointing in the right direction.
It is easy to see the WiTrack technology being used for video games as well as monitoring elderly people at risk of falls, but its true potential may be far greater. This is in part because the radio signals it uses are of very low power (100 times less than Wi-Fi and 1000 times less than what cell phones use) and the physical technology is already cheap to produce, and could be made cheaper.
Posted: December 11, 2013 06:45PM
In most situations, we find that plastics are electrical insulators, but in the seventies it was discovered that some were actually semiconductors. Now researchers at Linköping University, and many other institutions around the world, have found a polymer that is a semimetal, which could affect the future use of thermoelectric devices.
Semimetals are a family of materials resting between metals and semiconductors, characterized by a small bridge between the conduction electron bands of their atoms, and the valence band. This means they do not have a band gap, but they also do not have much room for electrons at the energy level needed to conduct. The idea that a polymer can be a semimetal was first hypothesized a few years ago, when a high thermoelectric effect was measured in a polymer. This indicated it was a semimetal, but was not proof on its own. Bow the team of twenty scientists from around the world have confirmed that a doped version of the plastic PEDOT is a semimetal.
The high thermoelectric effect could have some interesting implications, in part because polymers are cheaper to manufacture, while the metals used in thermoelectric devices are quite rare and expensive. Now that we know the job can be done with polymers, a new field of organic electronics could grow.
Source: Linköping University
Posted: December 11, 2013 09:30AM
Anyone who works with computers, cars, and many other devices can tell you how hot they get, and all of that heat is coming from wasted energy. For some time, people have been trying to reduce or capture that wasted energy, and thermoelectric materials, which can convert heat into electricity, can help. Sadly, thermoelectric materials are hard to produce, and thus have been limited to laboratories, but now researchers at the Fraunhofer Institute for Physical Measurement Techniques IPM may be changing that.
For a thermoelectric material to be useful at capturing wasted energy, it has to have certain properties. Among these is ZT value, which relates to their efficiency, higher than one and the ability to withstand high temperatures without increasing resistance. One family of materials, called half-Heusler compounds, can satisfy these requirements, but have never been produced cost effectively before. That is what the researchers and their partners have changed by successfully producing the material, with most of the needed properties, in kilogram quantities.
With so many systems generating large amounts of wasted heat every day, it is obvious just how important this research could become. Hopefully it will not be long before these materials are fully, industry-ready.
Posted: December 10, 2013 09:34AM
Ideally, a user will use a different password for every online account they have, but the reality is that one person can have some many accounts, it is almost impossible for them to remember them all, without help. Some of these solutions though, can actually put your security at risk. Researchers at Carnegie Melon University however, have taken advantage of some cognitive research and built a system to aid a user's memory, without compromising security.
Our memory works by encoding information with connections, and generally the more connections, the more easily you can recall the information. For example, remembering a specific sentence is easier when the sentence is tied to pictures. This is what the researchers are using to help remember passwords, by creating an app that shows a user a few pictures, and asks them to create a story about a sentence long, based on the pictures. The password is then formed from parts of the sentence, such as the first letters. As the story is the key and only known to the user, the pictures do not need to be secured, but for further security, the app associates multiple image groups with one password, so the user will also have multiple stories associated with the password as well.
Currently the app is undergoing development as part of an undergraduate research project, but when finished, it could allow some to generate 126 different passwords, by memorizing just nine stories. There is one flaw to the system though, and that is the reliance on letters, while some sites require numbers, capital letters, or passwords of specific lengths. Just another bit of information to remember.
Source: Carnegie Melon University
Posted: December 10, 2013 08:19AM
So often it seems in science that technologies start with the most expensive materials and tools, making it nearly impossible to take out of the lab. Of course there are reasons why expensive materials, such as gold and silver are used, but it is always welcome research to find another, cheaper material that can do the job just as well, or even better. Such appears to be the case with plasmonics and aluminum, according to some Rice University researchers.
Plasmons are a kind of quasiparticle, formed by the coupling of a photon and electron. This combination can allow the energy of a photon to flow over a metal as though it were an electrical current, which can be exploited for some interesting optical devices. Gold and silver nanoparticles are often uses in plasmonics, in part because they do not oxidize. Aluminum does naturally oxidize, which has prevented it from being adopted as the materials response to different light frequencies has seemed to change in prior studies. This new research indicates however, that that the optical response of aluminum nanoparticles is partially related to the amount of oxidation. As aluminum oxidizes only to a point, this means that the changes to a nanoparticle's optical properties eventually stabilize, in a predictable way.
The researchers also discovered that plasmons on aluminum nanoparticles will obey quantum mechanics across a larger range than silver or gold nanoparticles. This could have a great impact on the future of plasmonics, in more ways than just reducing costs.
Source: Rice University
Posted: December 9, 2013 08:39AM
Gravity is a very odd phenomenon, in part because we do not really know where it comes from or how it is able to affect spacetime the way it does. Further complicating matters is that the gravity described by the General Theory of Relativity is not compatible with quantum mechanics. Thanks to the recent work of other researchers, some at MIT have developed a new theory concerning worm holes and quantum entanglement, which may explain the source of gravity.
The recent work considered what would happen if two black holes were entangled, and then separated. The conclusion of that work was that a wormhole would form between them, allowing information to be shared by the two objects, no matter how separated they are. The MIT asked a similar question, but worked with quarks, which are sub-nucleonic particles, and what would happen if they were entangled and separated. The researchers first mapped this onto a four-dimensional space, representing the one we live in, but then determined what it would look like in a fifth-dimensional space. The result was a wormhole.
As wormholes are believed to be connected by gravity, and that gravity exists in five dimensions, this conclusion could suggest that gravity originates from quantum entanglement. Just the idea that entanglement leads to some kind of geometry suggests some interesting questions, but if it does indeed lead to gravity, then the answers could be far more intriguing.
Posted: December 6, 2013 07:15AM
Black holes have been a part constant of science fiction for as long as I can remember, with storytellers using them as means to travel across the Universe and even to other universes. Of course, these concepts just exist within the realm of fiction. The reality of black holes though may be a bit weirder than expected, according to researchers at the University of Washington.
Quantum entanglement is an interesting phenomenon which links the quantum states of two particles. This means that the properties of one will dictate those of the other, when they are observed, no matter how physically separated the two particles are. What the researchers have done is considered what would happen if two black holes were entangled, and their conclusion is that a wormhole would form. The catch is that you would not be able to transport any information through the wormhole, because black holes do not allow light to escape. However, if you and a friend were to jump into the two black holes, what you would see and experience inside would be identical.
Perhaps this research will dash the hopes of some readers and writers, but it will likely increase our understanding of entangled quantum systems. Forming this theory required showing a relationship between quantum mechanics and classical geometry, which will be a useful tool for other researchers.
Source: University of Washington
Posted: December 5, 2013 11:35AM
First introduced in the 1970s, fiber optics has provided the world with high speed communication, and is now part of the backbone of the Internet. Since its introduction, the capacity of the technology has increased by an order of magnitude about every four years, through the development of associated technologies. Recently though, that trend has slowed as researchers have hit a bottleneck, but those at EPFL have found a way to greatly improve throughput in one advancement.
A datum traveling through an optical cable is represented by the presence or absence of a light pulse. This is works well for digital data, which is stored as zeroes and ones, but to protect the integrity of the data, each datum must be enough separated from the others that they will not interfere with each other. That means there is a fair amount of empty space in an optical signal. What the EPFL researchers have done is demonstrate an efficient way to reduce the necessary distance between two data. By making the pulses rectangular, so they are equal intensity over a range of frequencies, it is much easier to keep prevent interference, that would otherwise corrupt data.
The idea of creating these 'Nyquist sinc pulses' in optical fibers is not new, but this is the first time it has been achieved with nearly perfect rectangular pulses, and without a complicated infrastructure supporting it. To deploy this solution in an optical fiber network one would just have to replace the transmitters in the system, not the cables, and the new ones would be using technology that has already matured.
Posted: December 5, 2013 06:39AM
There are many situations where you want to measure the distance to an object, such as surveying or controlling an autonomous car. A common tool for those situations is the lidar rangefinder, which reflects laser light off of objects to make the measurement. Researchers at MIT have recently made some clever advances to the system, enabling it to use significantly less light, which should have some interesting benefits.
A typical lidar system will repeatedly fire laser pulses at a position, until it gathers enough consistent data to be confident in the distance, and moves on to another position. The new MIT system however only accepts one photon before moving on, but records number of pulses it fired before receiving the photon. This allows it to generate a map based just on that data, roughly indicating the reflectivity of different objects. Of course, capturing only a single photon puts the system at risk of being fooled by a stray photon, from another source. To correct for that the researchers are applying a statistical trick that takes advantage of the fact that such photons follow a pattern known as Poisson noise. Instead of just filtering out the noise pixel-by-pixel, this system considers how much filtering was required in adjacent pixels, as they will likely have similar reflective properties, at the same depth.
Altogether, this new system should be able to generate a depth map with just a hundredth the number of photons a conventional lidar system uses, and generate an image with one nine-hundredth the number of photons. This should result in energy and time savings, and should prove useful in low-light situations.
Posted: December 4, 2013 08:13AM
For billions of years, plants have been breaking apart water molecules to store solar energy in chemical bonds. Humanity has been trying to achieve a similar feat for considerably less time, and one issue with many of our attempts is the use of the expensive and fragile material, indium tin oxide (ITO). Researchers at Duke University however, have found that films of copper nanowire could do the job as well or better, while being cheaper and more flexible.
Like it or not, ITO has proven to be a very valuable material, thanks to its conductivity and transparency, but the rarity of indium and complicated manufacturing processes make it less than ideal. This has made the search for a replacement material an important one, and copper nanowires could be it. Copper is roughly one thousand times more common than indium, making it considerably cheaper, but also copper nanowires are much cheaper to work with as they can be printed directly onto materials, such as glass or plastic. Also important is that films of copper nanowires are transparent and flexible. Even when coated with nickel or cobalt, metals useful as catalysts for separating water molecules, the nanowires allowed almost seven times more sunlight to pass through them than ITO.
Currently the nanowires have only been used for half of the water splitting process, but the researchers are working on that other half. Once that is achieved, we could eventually see copper nanowires being used to build fuel cells that will fit in backpacks and cars, or being components of OLED lights, displays, and smart glass.
Source: Duke University
Posted: December 3, 2013 08:53AM
One of the weird aspects of quantum mechanics is that observing a system can change it, causing information to be lost. This is a challenge for quantum computers, which require information is stored in qubits for extended periods of time. Researchers at NIST and other institutions however have found actually protect the information in qubits by causing them to give up information.
Typically, once information is encoded into the quantum states of particles, forming a qubit, one would want to protect it from the environment and any interference that could cause that information to be lost. What the NIST researchers have done though is taken advantage of that interference to protect the information they want. The researchers used two ultraviolet lasers to entangle two beryllium atoms, forming a qubit, and had two partner magnesium ions nearby. With an ultraviolet laser and microwaves, the researchers caused the qubit to release information to the magnesium ions, but that information only concerned properties of the particles besides their entanglement. The magnesium ions were then cooled with multiple lasers, causing that information to be lost to the environment.
Eventually what happens is the qubit enters a ground state where only the desired entanglement is left, and it is protected from electromagnetic fields. Essentially, everything unwanted about the qubit was removed, so only what the researchers wanted was left, making it hard to destroy. The researchers found they could successfully entangle the correct state within milliseconds, 75% of the time, and with more time the accuracy grew to 89%.
Posted: December 2, 2013 06:13AM
Self-healing polymers are pretty cool materials that have the ability to repair cracks, scratches, and cuts on their own. If an object has lost a major piece of itself though, the self-healing property will not be able to do much. Researchers at the University of Pittsburgh and Carnegie Mellon University however have developed a model for materials with the ability to regenerate bulk sections.
Regeneration is not a new concept for science, as many animals are able to regenerate severed limbs. This already-studied process helped the researchers identify the criteria for this work: initiation; propagation; and termination. To allow a material to sense when a portion of itself has been removed, the researchers added nanorods, of which the ones nearest to the new surface, move towards it. These nanorods then will cause polymerization reactions with molecules in a solution, to grow more of polymer. Through the computer model, the researchers also realized how to control the process, so as to stop it when necessary, and ensure the newly-grown material looks like the old one.
As this is currently just a computer model, it could be years before an actual regenerating polymer is created. For now though, the researchers will continue to work to optimize the model for when that polymer is ready to be made.
Source: University of Pittsburgh
Posted: November 28, 2013 09:10AM
Though not exactly news, here is a topical and interesting story from the Optical Society, which will be celebrating its one hundredth birthday in a few years. If you know someone that has undergone laser-assisted in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) surgery, of have undergone it yourself, you can actually thank the traditional Thanksgiving dinner of turkey.
In 1981, a group of researchers were working with an argon fluoride (ArF) excimer laser, which is capable of producing short pulses of ultraviolet light. Thanks to the high frequency and short bursts of the laser, they believed it should be possible to use the laser to cleanly cut tissue, without damaging cells around or behind it. Testing this hypothesis was proving difficult though, as the researchers could not immediately decide on a sample to use. During Thanksgiving dinner though, one of the researchers realized that a turkey bone with some cartilage would be perfect, as it is rigid and has a smooth surface. The next day the researcher brought in the bone, put it under the laser, and made multiple clean cuts in it. The researchers also used a green laser for comparison, and found it did considerably more damage to surrounding tissue than the ArF laser.
At first the team of researchers was finding it hard to share their results, but once they got out there, ophthalmologists and other surgeons approached. Earlier this year the team received the National Medal of Technology and Innovation for their work that has corrected the vision of million, and may go on to help even more in other ways.
Source: The Optical Society
Posted: November 27, 2013 06:50AM
Though many people may only associate 3D photography with movies, it is a growing technology that will likely find use in many fields, such as medical imaging, sensors for cars, and gaming. Researchers at MIT have recently demonstrated a 3D camera that uses time-of-flight technology and can achieve a time resolution approaching femtoseconds.
Time-of-flight (TOF) technology is pretty straightforward as it simply relies on the fact that the speed of light is known, so by measuring how long it takes a light pulse to reflect off an object, one can determine the distance to that object. This is how Microsoft's new Kinect technology works. One problem with TOF cameras is that they do not work well with semi-transparent or translucent objects. The researchers have managed to overcome that issue by applying algorithms similar to those that sharpen photos taken by a shaky hand. Combined with some other tools, the $500 camera is able to reach towards femtosecond resolution, making it a 'nano-camera.'
Of course, at $500 this is not particularly cheap technology, but because of this camera's similarities to the new Kinect, prices could drop due to the games industry. Once that happens, the MIT researchers will have already produced a number of ways for people to utilize the technology.
Posted: November 26, 2013 04:54PM
Have you ever noticed yourself picking up the expressions and mannerisms of others you spend a lot of time with? This is not uncommon and has some physiological basis. Researchers at Aalto University and Helsinki Institute for Information Technology have recently found that this linkage also occurs between two people playing video games together.
With facial electromyography to measure the reactions of facial muscles, and an EEG to measure brainwaves, the researchers pitted gamers against each other in a game called Hedgewars. This game features hedgehogs with artillery and the goal is to eliminate your opponent's hedgehogs first. When two human players were competing, the measurements indicated that their negative emotions became synchronized. Curiously, the more competitive the game, the more the positive emotions also became linked.
The researchers are not entirely sure why the linkage strengthened as the situation became more stressful, but it is possible this is to allow one to better anticipate their opponent, or to preserve any social bonds. The latter could definitely be true as the players were friends prior to playing the game, and would not have wanted to threaten that.
Source: Aalto University
Posted: November 26, 2013 08:02AM
Oh graphene, we hardly knew your high conductivity and two dimensional surface, and now you may be replaced. Well, at least in some scenarios, if researchers at SLAC National Accelerator Laboratory are correct about a prediction concerning stanene, a two dimensional form of tin. The name comes from the Latin word for tin, stannum, and the suffix used in graphene.
This latest work originated from a search for topological insulators. These are a special class of materials that conduct electricity along their surface without a speed limit, but resist electrical currents through their volume. Several of these materials have been discovered before, but none have had the necessary properties for use at room temperature. Knowing to look in the lower-right portion of the periodic table, the researchers have found that two-dimensional tin with some fluorine atoms should be a topological insulator at temperatures as high as 100 ºC.
If stanene were used in electronics, such as the wiring within microchips, we could see a significant drop in power consumption and heat, as an electrical current would travel with 100% efficiency. Of course, there is a lot of work to be done before then, including confirming the researchers predictions, and then, if accurate, developing a reliable means to manufacture stanene, which will not be easy.
Posted: November 25, 2013 07:11PM
Ferroelectric materials are a special class of materials that have the unique property of switching polarization when an electric field is applied. This property could see use in advanced forms of computing and memory storage, in part because electric fields are very easy to create. Researchers at Oak Ridge National Laboratory however, have made a rather unexpected discovery while writing domains of switched polarization onto a ferroelectric material.
Normally one would expect that when writing domains to a material, they would simply be written where and as you want them to be. As the domains got closer together though, forming denser arrays, the domains started affecting each other. Sometimes a new domain would not form or it would form with an alternating, checkerboard pattern. Not only has this never been seen before, but at first the researchers thought this was impossible. Upon further examination, the researchers determined that this behavior was chaotic, which is typically seen over a length of time, and not over a distance in space.
With one domain able to affect those immediately next to it, and far away, this discovery could have impacts on memcomputing. This field of computing attempts to mimic neurons in our brains, which are able to both store and process information. Of course, far more research must be done before a computer operating on this domain interaction effect could be built.
Source: Oak Ridge National Laboratory
Posted: November 25, 2013 07:37AM
Right now there are high energy particles called neutrinos streaming through your body. These particles are produced from high energy events, such as the nuclear fusion of the Sun and experiments at particle accelerators. There are other sources of neutrinos in the Universe, and the IceCube observatory, manned by researchers from across the world, including Berkeley Lab, is helping to find them.
Neutrinos are an interesting family of particles that have very little mass, high energy, and no electrical charge. This makes them very useful, as they can pass through barriers like the atmosphere, and difficult to work with, because they do not always interact with a detector. The IceCube observatory however was designed to catch them, with its 5160 detectors buried under a kilometer and a half of Antarctic ice. So far it is found 28 extremely high energy neutrinos that most likely occurred from astronomical events that took place outside of the Solar System. Two of these were the highest energy neutrinos ever reported then, exceeding one quadrillion volts, and one more actually doubles that.
Now that we are finding some of these neutrinos, the question becomes, 'where are they coming from?' IceCube can point us in the right direction, and currently the best theory is that they are being produced as a result of particle jets from black holes.
Source: Berkeley Lab
Posted: November 22, 2013 08:00AM
Nowadays, everything is designed on a computer before being manufactured, including parts of an airplane, jet engine, and gearbox. Such components though can suffer friction and impacts that cannot be properly modelled on computers, making prototypes a necessity for safety. Researchers at the University of Bristol want to change that and have crafted a new modelling technique that can accurately predict the effect of those forces, without a prototype.
Algorithms to predict the damage a device will incur as a result of friction or impacts have been developed before, but have not been very accurate. In part this is because some of those behaviors are so nonlinear that they create great uncertainty in engineering systems. The new Bristol model however is able to better describe what happens as it takes effects into account previous models had not.
This model could have a number of impacts, including greatly reducing the cost of engineering systems that endure friction and impact. It could also affect the modelling of non-smooth systems.
Source: University of Bristol
Posted: November 21, 2013 07:06AM
We all know how important cooling is in our computers and can imagine how important it is in even larger devices. This is why so much is invested in developing better cooling systems. Researchers at MIT have recently found a rather intriguing means to improve cooling using magnets.
Many systems, such as power plants and some computers, use water to remove heat. As the water flows through a pipe and over a heat source, it picks up the thermal energy, and carries it away. Many techniques have been developed to improve that process, such as adding structures to the pipes, to increase surface area or pumping the water faster, which can be expensive and require a lot of energy. This new technique instead adds nanoparticles of magnetite to the water. Magnetite is a kind of iron oxide and, as the name suggests, is magnetic. By then placing a magnet on the outside of the pipes, the particles are drawn towards one side of the pipe, which disrupts the water flow and increases the temperature gradient of the water in that area. The end effect is an increase in performance by as much as 300%.
Though this is currently just a promising study, it could one day have implications in fusion reactors and our computers. Part of that impact could be from strategically placing the magnets, to cool particular hotspots better.
Posted: November 20, 2013 10:52AM
We have all come accustomed to LCDs as they surround us in phones, televisions, monitors, cameras, and more, but that ubiquitous technology has a rival that could potentially take its throne. That technology is the organic light emitting diode (OLED) and it has several qualities that could make it the display technology and light source of tomorrow, but tomorrow has not yet come. Researchers at Fraunhofer-Gesellschaft though have brought that day a great deal closer by finally starting to realize a promise for OLEDs.
The organic compounds used in OLEDs are naturally flexible. While this obviously allows for OLED displays and lights to be flexible, it can also allow for those devices to be printed like a newspaper. Put the ingredients in one end of the machine and at the other end, you get a finished product. Thus far though, such printing technology has been limited to laboratories and not ready for commercial manufacturing. That is what the researchers have started to change by developing the technology for large-scale printing of OLEDs and other organic electronics. The printer uses a robot to control the printers that spray layers of the appropriate polymer molecules onto a plastic substrate, like an inkjet printer deposits ink on paper. When done, you have a working organic-electronic device.
In its current form though, this printing technology is not quite ready for commercial use, in part because it is still expensive to set up. This will limit the potential applications of the printed OLEDs, but with the technology now available, others can learn from and improve it, and perhaps build something capable of mass production.
Posted: November 19, 2013 06:45PM
For most people, if they were to hold a piece of metal and a crystal in their hands, they would think the two materials have nothing in common. That would not be completely true as they are both crystals, meaning the molecules within them have a regular structure. When a material does not have such a regular structure, they are considered a glass, and metallic glasses are very interesting for many applications. One problem with them though is their brittleness, but researchers at Berkeley Lab and Caltech have found something that may help change that.
Thanks to their irregular molecular structures, metallic glasses can be stronger than their crystal counterparts, malleable as plastics, while also conducting electricity and resisting corrosion. With properties like those, it is not surprising that many industries are trying to use them. In bulk though, the glasses are brittle, so composite glasses, which can be less brittle, are used instead, but the researchers have found one kind of bulk glass that is as fatigue resistant as those composites. It turns out that palladium-based bulk metallic glasses have a unique staircase-like crack pattern within them. This pattern protects against large cracks by limiting the opening and closing of the any cracks.
If this pattern can be replicated in other metallic glasses, we may see pure, bulk metallic glasses being used for a variety of devices in the future. Such devices could include smartphones, biomedical implants, and more electronic devices.
Source: Berkeley Lab
Posted: November 19, 2013 06:49AM
One classic physics experiment I have seen multiple times is to quickly submerge one's hand in molten lead. Normally molten lead would immediately burn your flesh, but thanks some water and the Leidenfrost effect, a barrier protects your hand from the heat. Sometimes you actually do not want such a barrier, such as when trying to cool a reactor, and researchers at MIT have found a way to potentially dial back the effect.
In the molten-lead example, the person first dips their hand in water and then quickly dips it in the molten lead. When the lead touches the water, it causes the water film to evaporate, creating a vapor barrier to block the heat from reaching your skin (if done correctly), giving you a brief window to withdraw your undamaged digits. In a reactor the same thing happens when water is sprayed onto it, causing some of the water to bounce off of the vapor barrier, and not carry away any heat. What the researchers have found is that if you put a pattern of microscale posts with nanoparticles attached to them that vapor barrier will not form until a much higher temperature.
While reactors and steam generators are two obvious applications for this research, it could also find use in fuel-inject engines and potentially electronics. It depends on if a spray cooling system could be made to fit inside an electronic device.
Posted: November 18, 2013 06:37AM
We are all fairly familiar with binary systems, such as power switches going between on and off, and data being stored as zeroes and ones. In some systems though, where quantum mechanics is the dominant form of physics, multiple mutually exclusive traits can coexist, and this is called a superposition. Superpositions, like many quantum states, are fragile though, which makes constructing a quantum computer difficult, but researchers at the University of Oxford have recently developed a qubit that survived for 39 minutes at room temperature.
The well-known Schrodinger's Cat thought experiment was originally developed to demonstrate how fragile a state can be, by showing that measuring a system can affect it. This is very true with quantum states where even a little bit of energy can cause them to collapse into classical states. Such fragility makes it very difficult to create a quantum computer that operates at temperatures much warmer than absolute zero, but the Oxford researchers were able to create a qubit at 4 K (four degrees above absolute zero) and then raise its temperature to room temperature. At 298 K (room temperature), the qubit remained in its superposition for 39 minutes, which shatters the previous record of roughly two seconds.
Such a robust qubit could greatly impact efforts to build quantum computers as it seems to have no noise. Of course there is a catch though. The qubits the researchers made consisted of phosphorus atoms doped into silicon with other elements, and all ten billion phosphorus atoms were given the same quantum state. A quantum computer will need more diversity of quantum states to be very useful.
Source: University of Oxford
Posted: November 15, 2013 07:42AM
A classic technology in many works of fiction is a tool to render a user invisible, and is often described as a cloak. When scientists actually learned how to make an object invisible with metamaterials though, 'cloak' would hardly describe the large devices. Researchers at the University of Toronto however have created a thin cloak that operates in a different way than the previous cloaks.
The first invisibility cloaks used metamaterials to cause light to bend in unnatural ways. As this requires special structures to achieve, the devices were somewhat large, and had to completely cover the object to work. This new cloak however uses a layer of antennas covering the object, which is considerably thinner. The antennas create an electromagnetic field that cancels out any light reflected off of the object. As it is only when light reflects off of an object that it can be seen, this renders the object invisible.
Currently the device has only been demonstrated with radio waves, but as the technology matures it should be able to work with light in other parts of the spectrum, including visible light. While the ability to make a target invisible would have an obvious military value, this cloaking technology could also be applied to remove obstacles that would otherwise block wireless signals.
Source: University of Toronto
Posted: November 14, 2013 05:53PM
Ever wanted to build your own electrical circuit, but cannot afford the lithographic technology typically used to fabricate them? Thanks to the efforts of researchers at the Georgia Institute of Technology, the University of Tokyo, and Microsoft Research, you may be able to print your circuits for only about $300.
By modifying a commercially available inkjet printer, the researchers were able to print working circuits in just sixty seconds. The circuitry was made from silver nanoparticle ink, which took advantage of recent work in how metal particles chemically bond to avoid thermal bonding. Such thermal bonds could actually damage the circuitry, and would at least add time to the process. As important as the ink though was the medium it was printed onto. The researchers found that resin-coated paper, PET film, and glossy photo paper worked well, and that canvas or magnetic sheets did not.
To prove this approach to printing circuits work, the researchers connected a capacitive ribbon with embedded circuits to a drinking glass. This formed a sensor that could measure how much water was in the glass.
Source: Georgia Institute of Technology
Posted: November 14, 2013 07:46AM
Carbon is an important element for modern life, and not just because of its necessity for biochemistry. The element is also found in many materials and devices we use daily, in one form or another. Researchers at Virginia Commonwealth University, Peking University, and the Shanghai Institute of Technical Physics have recently discovered a new, theoretical, three-dimensional form of carbon with the special property of being a conductor at standard temperature and pressure (STP).
The saying may be 'diamonds are forever,' but the chemistry is the opposite as graphite is actually the most stable form of carbon at STP. This means that diamonds, graphene, fullerenes, and nanotubes, if left alone at room temperature and pressure, will eventually decay into graphite. As graphite is a rather poor electrical conductor, researchers have been looking for another crystalline structure of carbon that is stable at STP, but is a good conductor, and it appears the researchers have found one, in theory.
This new form of carbon is comprised of tetrahedrons that interlock to form hexagons, and these hexagons give it its electrical conductivity, like they do in graphene. Being theoretical and early in development though, it may be some time before this carbon allotrope is synthesized, but when it is, it could have applications as a lightweight metal or low-resistance conductor.
Source: Virginia Commonwealth University
Posted: November 13, 2013 12:08PM
Organic Light Emitting Diodes, or OLEDs, are a light-generating technology many people and companies are interested in for use in displays on phones, cameras, and even some televisions. They potentially offer cheap displays that are still bright and vibrant, but still have issues. One of these issues researchers at the University of Bonn, Regensburg University, the University of Utah, and MIT have managed to solve, and it should lead to a bright future.
In general, LEDs, organic or otherwise, generate light when a negative electron meets a positive hole, and energy is released as a photon. The problem is that it is not as simple as that, due to quantum mechanical effects. Specifically, if the spins of the two charge holders are the same, they will not collide and release energy as a photon, but instead create unwanted heat. Traditionally this was addressed by adding certain metals, such as platinum or iridium, which are both rare and expensive. What the researchers have found though is a new OLED design that allows it to hold energy long enough for the spins to flip naturally.
By removing the need for the noble metals, this research could significantly decrease the cost of OLED displays. Also, because more energy will be converted to light than heat, the resulting displays should be brighter and more efficient.
Source: University of Bonn