Science & Technology News (1216)
Posted: April 29, 2016 11:08AM
As silicon-based electronics approach their theoretical limitations, many new technologies are being developed and investigated for replacing this long-lived standard. Among these are optical based systems that use photons or plasmons for transmitting, processing, and storing data. Researchers at ITMO University have recently found a way to build hybrid nanoantennas that could help optical technologies replace modern devices.
There are a number of reasons why people want to see photons replace electrons in computers, including their greater speed, ability to store more data, and the fact that they do not generate as much heat when used. Working with them, however, is difficult and require precisely created nanoantennas to localize light to specific areas. Building these nanoantennas is not easy, but the ITMO researchers have found a way to create arrays of hybrid nanoantennas, and to adjust those antennas. The antennas themselves are comprised of a truncated silicon cone with a particle of gold on top. This gold particle may start as a disk, but with a femtosecond laser, it is possible to change its shape to a sphere or a cup, altering the antenna's optical properties. This will allow the nanostructure to have its properties manipulated to fit desired roles.
These nanoantennas are roughly the same size as a bit in a modern optical disk, which can store about 10 Gb/in2. Unlike those bits though, the antennas are able to control the color of light, so if used for data storage, the capacity would be greatly increased by this added dimension.
Source: ITMO University
Posted: April 28, 2016 08:02AM
Ever since electronic computers were first developed, one of their primary applications has been for simulating various systems. These simulations allow predictions to be made but they are also a means for researchers to more closely study and analyze the processes involved. Some systems are harder to simulate than others, such as those ruled by quantum mechanics, because of how fragile they are, but researchers at the University of New South Wales have built a device that could serve as a quantum simulator.
The idea behind many simulators is to take a hard to examine process or system, and recreate it in an environment more easily studied. A computer simulation allows every aspect to be studied, but quantum systems can be so complicated that even the most powerful supercomputers cannot run them efficiently. What the New South Wales researchers have done is doped a pair of boron atoms into a silicon crystal, separated by just a few nanometers. In this configuration, they behaved like valence bonds, which are what hold many molecules together when the orbits of unpaired electron overlap. The researchers were then able to directly measure the clouds of electrons around the atoms, and the interactions between the spins of the electrons.
The observed behavior in this simulation matches the Hubbard model, which is what describes how electrons interact, with their wave-like properties, and is central to explaining many phenomena. The researchers also made a curious discovery as the electrons involved were entangled with each other, but this entanglement actually increased with their separation, instead of decreasing. It is quantum mechanics though, where the counterintuitive is so often the norm.
Source: University of New South Wales
Posted: April 27, 2016 09:14AM
It might not be the most pleasant image for some people, but we are approaching a time when robotic drones will be freely moving around us for various reasons. In some cases a swarm of robots might be used instead single drones, which makes it vital that they all act in concert. In general this can involve centralized or decentralized algorithms, and now researchers at MIT have developed a new decentralized algorithm that significantly reduces the amount of communication needed between the drones.
A centralized algorithm for controlling a swarm involves having a single computer make all of the decisions for a swarm of robots, which is fine unless that computer goes offline. Decentralized algorithms, where each robot is making its own decisions, do not suffer from these problems, but are much harder to design as each robot guesses what the others are doing. To that end, these algorithms will have the robots scan their local environment for obstacles and transmit their map to the rest of the swarm, so everyone robot has the same information to work with. What the new MIT algorithm does is cut down on the size of the map dramatically by only transmitting the intersection between different maps. So after the first drone transmits its complete map to its neighbors, these neighbors identify the overlap with the map they constructed, and then that is transmitted.
As this intersection is significantly less information than the entire, composited map, it cuts down on the communication between the drones, but the robots will still have a map of every detected obstacle. It also works for detecting moving obstacles and is completed many times a seconds, so sudden changes in an obstacles velocity should not be an issue.
Posted: April 26, 2016 08:50AM
When it comes to storing electricity, the two main ways to do so are batteries or supercapacitors, which both offer their own advantages and disadvantages. Hybrid batteries try to combine the two to get the best of both worlds, and now researchers at PNNL have found a way to make them even better.
The advantage batteries come with is tremendous energy density for their size, while supercapacitors store less energy but can be very quickly charged and discharged, unlike batteries. Hybrid batteries contain both technologies by making the electrodes out of supercapacitors, so that one can have a fast charging and long lasting device. These electrodes can be made from carbon nanotubes and it has been discovered before that spraying polyoxometalate, or POM onto them can improve their performance by adding ions to the surface. The catch is that only negative ions are desired, but POM includes both positive and negative ions. What the PNNL researchers did is change the method of applying the POM to ion soft-landing, which allows for precise control over what is applied; in this case applying only negative ions.
The resulting hybrid batteries stored 27% more energy than those made by more conventional methods. They also only lost a few percent of their capacity after 1000 charge and discharge cycles, while the conventional hybrid batteries were at half-capacity by then. When the researchers closely examined the electrodes they found that the ion soft-landing method allowed the negative ions to more evenly cover the electrodes, while the positive ions deposited by other methods resulted in the material clumping up on the electrode. This also means less POM was needed to achieve optimal results.
Posted: April 25, 2016 08:25AM
Something shared across many video games are certain specific archetypes, such as tanks, fighters, mages, rogues, assassins, and so on. In some games you are able to select what role you get to play as, while in other games it may be selected for you, or never even described. Researchers at North Carolina State University decided to look into these roles and see if they influence a player's behavior, and if selecting a role makes any difference.
To do this experiment, the researchers create a single-player RPG (which you can play at http://go.ncsu.edu/ixd-demo-rpg) and had 210 people play it. Of those, 78 were assigned the role of fighter, mage, or rogue, while 91 were allowed to select their role, and the final 41 played without a role. The game contained twelve multiple choice decisions that were careful constructed to be aligned with the three roles, to see if players maintained the role as they played. The results showed that whether the players selected or were assigned the role, they maintained them most of the time, with fighters being consistent 65.7% of the time, mages 76.1% of the time, and rogues 69.7% of the time. Even for the players who were not given a specific role, made decisions consistent with a specific role.
This study indicates that even without explicit role-playing elements to a game, players will assume and maintain roles on their own, which could influence how game designers develop games. It also means that other studies that examine player choice should be careful to remove role as a variable, as it could skew results.
Source: North Carolina State University
Posted: April 22, 2016 06:58AM
Wireless communication is something many of us rely on today for connecting or various devices to the Internet, so there is a constant drive to increase wireless speeds. One way to achieve this is to build systems that allow for the simultaneous transmission and reception of signals, but achieving this is somewhat difficult with a single antenna. Researchers at the Columbia University School of Engineering and Applied Science though have built an on-chip solution that could bring full duplexing and doubled speeds to devices like our phones.
Currently many devices use half-duplexing to connect to a Wi-Fi network, which means that while one antenna is sending and receiving all of the information, it is not doing so at the same time. This is because the electronic structures used exhibit Lorentz Reciprocity; electromagnetic waves travel in both directions at the same time. One way to overcome this issue requires using magnetic materials to create a radio frequency circulator. When the material is exposed to an external magnetic field, reciprocity is lost, allowing the incoming and outgoing signals to be separated. Such circulators cannot be integrated into silicon chips though, and even then they are rather large for using in something like a phone. To solve this problem, the Columbia researchers created a new, electronic circulator that is highly miniaturized and uses a set of capacitors to replicate the non-reciprocal twist the magnetic circulators produce.
The researchers have already demonstrated this new circulator design by building a prototype of their full-duplex system that also features an echo-cancelling receiver. By integrating the circulator into the same chip as the rest of the radio, it should be possible to keep the size of the system and the cost down, allowing for full-duplex communications and potentially doubling network capacity.
Source: Columbia University
Posted: April 21, 2016 12:38PM
The next time you archive some files and compress them, you might think about the process a little differently. Researchers at the National University of Singapore have discovered a common compression algorithm can be used to detect quantum entanglement. What makes this discovery so interesting is that it does not rely on heavily on an assumption that the measured particles are independent and identically distributed.
If you measure the property of a particle and then measure the same property of another particle, in classical mechanics there is no reason for them to match but pure chance. In quantum mechanics though, the two particles can be entangled, such that the results will match each other. This follows from Bell's theorem, which is applied to test if particles are in fact entangled. The catch is that the theorem is derived for testing pairs of particles, but many pairs have to be measured and the probabilities they are entangled calculated. This is where the researchers' discovery comes into play because instead of calculating probabilities, the measurements can be fed into the open-source Lempel-Ziv-Markov chain algorithm (LZMA) to get their normalized compression difference. Compression algorithms work by finding patterns in data and encoding them more efficiently, and in this case they also find correlations from quantum entanglement. If the data is classical, the normalized compression difference must be less than zero, but with quantum mechanics it can reach 0.24.
When tested, this approach returned a value of 0.0494 ± 0.0076, which shows the data did cross the classical-quantum boundary. It is below the 0.24 theoretical maximum because the quantum states cannot be created and measured perfectly, and the compression algorithm is not ideal.
Posted: April 21, 2016 07:01AM
While many of us may be transitioning to solid state data storage for greater read and write speeds, magnetic storage devices still have great data density. That density may be hitting new highs in the future as researchers at EPFL have demonstrated single-atom magnets that remain stable at a new record-high temperature of 40 K.
Magnetism is the result of the spin of electrons, which is a quantum mechanical property but works on the macroscale when the spins of many electrons line up. In a single atom though, the spin of an electron can be easily flipped by the environment, with magnetic remanence describing how well a magnet remains magnetized. The researchers were able to build prototype single-atom magnets using holmium atoms that were placed in ultrathin films of magnesium oxide. The electronic structure of the holmium atoms protect their magnetic fields from flipping, and at 40 K, the magnetic remanence is stable. Previous magnets consisting of three to twelve atoms have required even lower temperatures or poorer remanence where the holmium magnets are stable.
While 40 K is a bit too low for many practical uses, this still sets the record for smallest and most stable single-atom magnet, the ultimate goal for miniaturized data storage. Hopefully we will see this record broken before long.
Posted: April 20, 2016 08:34AM
Heat engines have been around for a long time and are used to convert thermal energy into mechanical force. Now thanks to researchers at Johannes Gutenberg University, a single atom has been turned into a heat engine, which could have applications for studying thermodynamics and quantum thermodynamics.
The core of this heat engine is a single calcium atom that has been electrically charged to be held in a trap. It can then be heated with electrically-generated noise and cooled with a laser beam, which results in it going through a thermodynamic cycle. That means the atom moves back and forth within the trap, just like the strokes of a heat engine. While the single atom only generates 10-22 watts at 0.3% efficiency, scaling the engine up to match the mass of a car engine, the output would be comparable.
Chances this design will not be used to actually generate power, but instead be used to study the thermodynamics of single-particles and if the operating temperatures can be lowered sufficiently, it could become a window to thermodynamic quantum effects. It is also possible to reverse the cycle to make it a single-atom refrigerator for cooling nanosystems.
Source: Johannes Gutenberg University
Posted: April 19, 2016 02:03PM
Currently thin is in for many devices, including phones, tablets, and laptops, but in the future we may see flexibility become the physical feature of choice. For some technologies this makes sense, as the flexibility can allow it to be deployed in more places by wrapping around any object. Researchers at Columbia University are working towards flexible cameras and have recently developed a flexible lens array without aliasing artifacts.
One way to create a flexible lens array is to attach rigid lenses with fixed focal length to a flexible material, but it has a significant flaw. As the material is bent, gaps will form between the lenses' fields of view. The researchers solved this problem by making the lenses themselves flexible, so the bending alters the focal length as needed. This prevents any gaps, or aliasing artifacts from forming, and it was achieved passively by optimizing the geometry and material properties of the silicone used, so no special mechanical or electrical systems are needed.
This lens is just half of a flexible camera as a large-format flexible detector also has to be developed. Once that is created though, the new class of cameras will have many new applications not currently possible with rigid cameras, and we could potentially see them made cheaply, like a roll of plastic.
Posted: April 18, 2016 09:09AM
So many items around us are becoming connected now, and eventually even our clothes will contain electronics. Creating e-textiles has not proven to be easy though, as textiles must be flexible while electronic components are typically rigid and fragile. Several advances have been made over recent years though, and now researchers at Ohio State University have successfully found a new means of embroidering circuits into clothes.
Previously the Ohio State researchers worked with a silver-coated polymer thread that measured about 0.5 mm in diameter, with each thread consisting of 600 smaller filaments. What the researchers have done recently though is switch to a new thread just 0.1 mm in diameter and made of just seven filaments. This new thread has a copper core that is enameled with pure silver, but is still able to be embroidered like a traditional thread. The researchers have already demonstrated this by feeding it into a sewing machine that then embroidered different shapes into textiles, and these shapes were functional circuits and antennas. In fact, a broadband antenna they made, which is able to work over a broad spectrum of frequencies like our mobile devices, showed off near-perfect efficiency from 1 to 5 GHz.
Potentially this antenna design could be allow our clothes to boost the reception of smartphones and tablets. The wire used costs about three cents a foot, and just one antenna takes about ten feet, so that is thirty cents, which is 24 times cheaper than similar antennas the researchers made in 2014. It is also cheaper because the technique has been refined so that only one embroidered layer is needed, saving on time and material.
Source: Ohio State University
Posted: April 15, 2016 08:44AM
When recharging a battery, it will start to heat up and for many applications, that is not too big a problem, but in some cases that heat can kill the battery, and even ignite it. To address the issue, work is being done to develop new battery components that can take the heat. Researchers at Rice University have recently developed a new combined electrolyte and separator that can survive temperatures up to 150 ºC.
Last year this same group of researchers discovered a kind of clay could be used as an electrolyte that would work at up to 120 ºC. From that work they speculated that hexagonal boron nitride (h-BN), or white graphene, could do an even better job. It is called white graphene because it is structurally similar to normal graphene, a form of carbon that is just one atom thick. Unlike graphene though, h-BN is an insulator and is also not a good ionic conductor. With properties like that, one would not expect it to improve a battery's performance, but it actually did. Despite being a relatively inert material, it combined with a piperidinium-based ionic liquid and lithium salt appeared to catalyze better reactions from the chemicals around it.
With the ability to operate from room temperature up to 150 ºC, the batteries using it can have very wide temperatures, which will be very important for some industrial and aerospace applications. For example, wellheads for the oil and gas industry require batteries that can survive the high temperatures they are exposed to. Non-rechargeable batteries have to be used currently, because only they can endure the temperatures involved, but now that may change.
Source: Rice University
Posted: April 14, 2016 07:36AM
As powerful as modern computers become, there are some operations they will never be able to do very well. Quantum computers however, do have the potential to complete some of these operations very quickly, because of the quantum mechanical effects they have at their disposal. The catch is that quantum mechanical systems are as fragile as they are powerful, but researchers at MIT have developed a new means of stabilizing quantum bits.
In traditional computer, information is stored with the charge of electrons, but in quantum computers, the quantum bits or qubits store information with properties that can enter a superposition. Superposition is a quantum mechanical phenomenon that allows a particle to exist in multiple, usually exclusive states, but is also very fragile. The qubit in this case is a nitrogen-vacancy (NV) center within a diamond. A pure diamond is comprised of carbon, but researchers discovered that by replacing a carbon atom with a nitrogen atom, and removing another carbon atom next to it, creates a quantum system that can be used as a qubit. What the researchers did is use microwave exposure to entangle the state of the electrons within the nitrogen-vacancy, with the state of the nitrogen atom's nucleus. This entanglement means that if anything goes wrong when the quantum computations are done, both the NV center and the nucleus will be affected. After the computation is completed, the nucleus and NV center are disentangled and are exposed to additional microwaves. These microwaves have been calibrated though, so that their effect on the NV center depends on the state of the nitrogen nucleus, so only if an error occurred would the qubit be touched.
With experiments the researchers found this method allowed the qubit to stay in it superposition for about a thousand times longer than if the method were not used. Obviously that is a significant accomplishment and we could see it quickly being used to as part of new protocols for quantum computing.
Posted: April 13, 2016 12:02PM
This bit of research is from the University of Montreal, which might not be all that surprising. Researchers there have discovered at maple syrup can actually help protect neurons from amyotrophic lateral sclerosis, or ALS. Before you start downing any syrup though, this study was done with C. elegans worms that do not have to worry about illnesses like diabetes, and was just for educational purposes.
The C. elegans worms used have been genetically modified to express TDP-43, which is related to ALS, and will result in 50% of the worms being completely paralyzed after two weeks. To see if maple syrup would make a difference, the worms were given some at various concentrations and compared with worms on a normal diet. At the two week mark, only 17% of the worms were paralyzed, showing that the syrup did in fact help protect them from the illness.
The reason maple syrup helped is because it contains sugar and some powerful antioxidants, polyphenols. Neurons use sugar for food, and diseased neurons need more to fight the toxic proteins associated with ALS. Two of the antioxidants identified, gallic acid and catechol, also have a neuroprotective effect, which certainly helped as well, even though they are only present in small concentrations.
Posted: April 12, 2016 07:58AM
As technology has advanced, video games have benefited with richer and sharper graphics, which is well demonstrated now by the virtual reality displays currently available and those scheduled to release later this year. This realism has resulted in several studies finding players will actually feel guilty after amoral acts, such as unjustified violence. Now researchers at the University of Buffalo have discovered gamers can become desensitized as they continue to play a particular game, and this spills over to similar games.
A sometimes used defense of violence in video games is that actions in a virtual world do not translate to the real world, but the findings that gamers feel guilty after committing these virtual acts would seem to challenge that claim. This new study adds on that playing a violent game over and over again desensitizes the player to this guilt, and that this applies to similar games as well. Why this happens and what the mechanisms are behind the desensitization is unclear though.
Currently the researchers have two arguments, with the first being that games become less sensitive to the stimuli causing guilt. The second argument considers tunnel vision, with a gamer's perception changing from that of a non-gamer with repeatedly play. Eventually a gamer might just be processing what they see differently, disregarding meaningless information and coming to recognize how artificial the virtual environment is. The researchers are planning future work to try to answer determine what the answer is.
Source: University of Buffalo
Posted: April 11, 2016 07:16AM
Undoubtedly encryption is a very important tool for securing communications, but modern encryption methods can all be beaten with clever tricks or brute force. In the future though, quantum encryption could be used to protect sensitive information in such a way that it cannot be compromised without the intended user's knowledge. Central to this kind of security is quantum key distribution, which has been limited to just hundreds of rather slow data rates, but researchers at the University of Cambridge have found a way to speed it up by up to six orders of magnitude.
Quantum encryption protects data because the key to decrypt it is transmitted using quantum mechanical particles, such as photons. When these photons are observed, to determine what the key is, their quantum mechanical properties change, meaning the key is altered and this can be detected. While theoretically quantum encryption cannot be broken, by attacking the real hardware components involved, it could potentially be compromised, so a protocol called measurement-device-independent quantum key distribution (MDI-QKD) was developed. While this has been demonstrated successfully, it has been limited to operating at just a few hundred bits per second, or less, because of how hard it is to create indistinguishable particles from the different lasers involved. The Cambridge researchers have addressed this problem by developed pulsed laser seeding for injecting photons from one laser beam into another. This method reduces the time jitter of the pulses, allowing them to be significantly shorter.
Using pulsed laser seeding, a data rate of up to one megabit per second is possible, which represents a one hundred to one million improvement factor. This new protocol could be leading us to the practical implementation of quantum cryptography.
Source: University of Cambridge
Posted: April 8, 2016 07:40AM
Many technologies we have today are only possible because of how much energy lithium-ion batteries can store, and their ability to be recharged. As the devices they power have improved though, these batteries have been approaching their limits, requiring new technologies or chemistry for the future. Thankfully researchers at NIST have found a way to improve the characteristics of a material that one day could serve as an energy storage medium.
The material in question is a compound of hydrogen and boron, and either lithium or sodium, with one of the boron atoms replaced with carbon. The researchers previously discovered this substitution improved the compound's ability to conduct ions by a factor of ten. What they have now found is a way to overcome an issue with its behavior at different temperatures. When in an environment hotter than boiling water, the material would conduct ions quite well, but at lower temperatures, such as room temperature, it lost its conductivity and thus its performance. The recent discovery is that by crushing the material into nanoscale particles, it maintains it conductivity at room temperature and far lower, making it potentially viable for batteries.
Now the researchers are investigating how the material might be used in next-generation batteries, with the hope of convincing people of the material's potential.
Posted: April 6, 2016 09:15AM
For many modern devices, the battery can be the bulkiest component, which is a problem as people demand smaller and thinner devices, without sacrificing battery life. One way to improve the performance of a battery is to use electrodes with 3D microstructured architectures, as these provide more places for ions to interact with. However, making such structures is difficult, but researchers at Aalto University have successfully demonstrated a way to build them.
This new method combines atomic and molecular layer deposition techniques to build thin films from lithium terephthalate. This is a hybrid organic/inorganic material recently found to be a viable anode for lithium-ion batteries. Surprisingly, even though lithium terephthalate is a hybrid compound, it survived the deposition technique that reaches temperatures between 200 ºC and 280 ºC. It also does not require conductive additives to achieve an excellent rate capability, but adding a protective layer of the solid-state electrolyte, LiPON does enhance its performance.
When the researchers tested the anodes they constructed, they found they retained 97% of their capacity after 200 charge/discharge cycles.
Source: Aalto University
Posted: April 5, 2016 09:34AM
Many people see electric vehicles becoming a dominant form of transportation in the future, but there remain several serious challenges to overcome. Among these issues are range and the time it takes to recharge batteries. Researchers at ORNL have recently achieved 20 KW wireless power transfer for vehicles that could help address both of these issues.
Wireless charging is something currently found today with several gadgets and small devices, because some enjoy the convenience of simply setting something like their phone on a special pad to charge it. Wirelessly charging a vehicle would provide a similar convenience, as one could park it in their garage and walk away. At 20 KW, this system is not comparable with commercial plug-in systems, but it does reach 90% efficiency, which is important for reducing wasted energy, but also keeping people safe from the magnetic fields involved. The researchers are already looking at reaching 50 KW, which would match those commercial units and make it a potentially viable product.
While parking a vehicle for several hours to charge is definitely a realistic scenario, the researchers also investigated this system's dynamic charging capabilities. This would mean an electric vehicle, like a bus that stops at specific places, could be partially charged while picking up or dropping people off. This would extend the bus's range between full recharges, but could also be applied to allow vehicles to charge without stopping.
Source: Oak Ridge National Laboratory
Posted: April 4, 2016 09:26AM
When most people think of titanium, I suspect many envision some very strong material that is used in only special situations like airplanes and spacecraft. Actually, titanium on its own is not all that strong and must be made into an alloy to get its amazing strength. Now, thanks to researchers at the Pacific Northwest National Laboratory, we may see titanium coming to cars because they have developed a new and very strong alloy that is also relatively inexpensive to make.
About fifty years ago, metallurgists discovered titanium could be combined with iron, vanadium, and aluminum to create an alloy called Ti185. This alloy is quite strong, but only in certain places because of how the mixture tends to clump and form defects. Six years ago, PNNL developed a new way to create Ti185 that uses titanium hydride powder instead of molten titanium, and now they have optimized the process to make an even stronger version. This optimization involved carefully examining the placement of the atoms within the alloy after it underwent heat treatment. Heat treatment involves heating a metal up to high temperatures and then rapidly cooling it water, which causes the atoms and molecules to be locked in arrangements they would not normally have. The researchers found that by repeatedly treating the alloy at specific temperatures, they could influence the structure to make the alloy stronger than before, and this whole process is actually fairly inexpensive.
The type of steel used in cars has a tensile strength of 800-900 megapascals, but this optimized Ti185 comes in at nearly 1700 megapascals, so approximately double the tensile strength while being half the weight. While still more expensive than steel, its strength-to-cost ratio makes it more affordable for use in lightweight vehicles, and this research could lead to other alloys that could be cheaper. For example, it might be possible to optimize alloys of aluminum to give them greater strength, while keeping costs and weight in check.
Posted: March 31, 2016 08:14AM
The ability to store electrical energy is of ever growing importance, as many nations push toward adopting technologies like solar and wind power, which do not always provide constant amounts of power. Storing energy on a large scale is not easy though, and can be very expensive as well. Fortunately, researchers at Sandia National Laboratories have developed an easier way to produce iron-nitride cores for transformers.
This new method starts by producing iron nitride powders by ball-milling iron powders in liquid nitrogen, followed by ammonia. The powders are then consolidated into a solid material using field-assisted sintering technique (FAST), which can be done at a much lower temperature than traditional sintering. This is important, as high temperatures could break apart the iron nitrides. It also can be completed in just minutes. Producing this specific kind of iron nitride in the past has required high-vacuum environments to produce thin-films, or only made it as inclusions with other materials.
Because the iron nitride is already magnetic, transformers using it at their core could be made much lighter and more compact, even allowing for open-air cooling. Potentially we could see it used to deploy energy storage and power conversion systems that fit inside a semi-trailer.
Source: Sandia National Laboratories
Posted: March 30, 2016 07:50AM
While 4G connectivity continues to grow, it should be no surprise that 5G is being developed across the world. This wireless standard will take advantage of several advances including multiple antenna technology, like MIMO currently used with Wi-Fi and 4G, though on a larger scale. Researchers at the University of Bristol, using their Massive MIMO System have set a new record for wireless spectrum efficiency.
The Massive MIMO system has 128 antennas at its base station and the researchers were able to connect 12 single antenna clients to it, all sharing the same 20 MHz channel at 3.5 GHz. The total throughput achieved was 1.59 Gbps, or a bandwidth efficiency of 79.4 bit/sec/Hz. This record should lead us to more efficient wireless networks by allowing more devices to use the same channel.
Source: University of Bristol
Posted: March 29, 2016 09:44AM
Quantum computers are coming, but not as soon as some science fiction has predicted because there is still a great deal of technology to be invented. Thanks to researchers at Griffith University and the University of Queensland though, we are a step closer as they have built a quantum Fredkin gate.
Like in modern computers, quantum computers will use logic gates to perform operations, but these gates will utilize quantum phenomena. To construct a large quantum circuit requires a great many smaller logic gates, but integrating so many gates together is difficult. Until now the Fredkin, controlled-SWAP gate has not been made because it would need five logic operators. The researchers overcame this by using photons to implement the operation directly, allowing the Fredkin gate to be built. What the gate does is swap two qubits, depending on the value of a third qubit. It can see use in a variety of algorithms, including Shor's algorithm for factoring large numbers, and can also directly compare two sets of qubits. The latter would be especially useful for secure quantum communications, by testing if two digital signatures are the same.
Source: Griffith University
Posted: March 28, 2016 07:20AM
With the ubiquity of digital cameras, people are taking all kinds of pictures, and if they are taking them through panes of glass, they might notice how reflections from the glass can disrupt the image. Naturally then, computer scientists have been searching for ways to remove these reflections. Now researchers at MIT have developed a method to remove reflections using a modified Microsoft Kinect One camera.
The key to this method is distinguishing between the reflected light and the light of the desired scene past the glass pane. To do this, the researchers are turning to the Fourier transform and the phase of the light. The Fourier transform is used throughout signal processing, as it is a means to break a complex signal up into the pure frequencies that comprise it. Describing these pure frequencies are their amplitude and phase, with phase being the offset of its crests and troughs. Differences in phase between two signals can be used to measure a signal's arrival time and thereby the distance from the camera. Typically, measuring phase is very difficult and therefore expensive, but the researchers came up with a solution by having the camera emit light of specific frequencies and feeding the algorithm information on how many reflectors are between the camera and the scene of interest.
Ideally the camera would only need to use one more frequency of light than there are reflectors, but because the emitted light is not going to be pure frequencies, the researchers used 45 frequencies. It took a full minute of exposure time, but the result was almost perfect image separation. It should be possible to make do with fewer measurements, but for now this is still an impressive accomplishment, considering it is using a modified consumer product, and not research-grade equipment.
Posted: March 25, 2016 03:06PM
Water is easily one of the most important materials on the planet, and while there is a great deal of it on Earth, very little is clean enough to use for drinking. For that reason, many technologies have been and continue to be developed to efficiently clean water. Now researchers at Monash University have made a discovery that could lead to a cheap means of removing contaminants with graphene and light.
Graphene is an atom-thick sheet of carbon typically investigated for its amazing electrical and mechanical properties. In this case though, it is how contaminants attach to graphene, and how it reacts with a special soap that is being used. When pieces of graphene are added to contaminated water, the contaminants stick to them. The soap that is also added does not immediately affect the graphene, but when the properly colored light strikes it, the soap's molecular structure changes. This change triggers the graphene to separate out, along with the contaminants, making it easier to remove the contaminants from the water. A different color of light will then allow the graphene to disperse back into the water, for reuse.
With light being quite plentiful, this could be used as a very effective means of removing contaminants from water, but there is still an important issue to overcome. While the graphene does separate from the water, it still needs to be extracted and the usual ways of doing so take large amounts of energy or adding a lot of polymers, which is costly. Hopefully it will not take long to address that issue.
Source: Monash University
Posted: March 25, 2016 08:49AM
If there is one thing true about the technology consumer, it is that we want more, especially more speed. Getting that additional speed is rarely easy though, but it will be necessary for telecommunications as demand for data continues to grow. To help satisfy future demand, researchers at the University of Illinois at Urbana-Champaign have achieved a new record of 57 Gbps for error-free data transmission at room temperature, and 50 Gbps at up to 85 ºC.
While the 57 Gbps transmission might seem more impressive at first, the 50 Gbps is very important. As the materials used in fiber optic transmission heat up, their performance degrades, making refrigeration systems necessary to cool them. By achieving such a high speed at 85 ºC, it will be possible to reduce the amount of cooling needed at data centers, and that needed for other commercial uses. For example, we could see this deployed in airplanes, as fiber optic cables are lighter than copper wires.
Posted: March 23, 2016 07:52AM
As has been the case many times, this scientific discovery began as an accident when researchers at the Joint Quantum Institute found more atoms were reacting to a laser pulse than could be readily explained. Because excited atoms like these could one day be used to build quantum computers, this discovery could require new designs be developed.
Something many students are taught every year in science classes is that electrons exist in specific, well-defined orbitals around the nucleus of an atom, and only by absorbing or emitting the correct amount of energy, will an electron jump from one orbital to another. By pumping enough energy into an atom, it can enter a Rydberg state where an electron occupies an orbital quite far from the nucleus. This distance makes so-called Rydberg atoms appealing for quantum devices, as the electrons can be worked with easily. When the researchers pumped a cloud of rubidium atoms to enter Rydberg states though, they found many more atoms were excited than predicted, which could negatively impact their usefulness in a device.
The researchers suggest what happened is that some atoms entering the Rydberg state contaminated others, allowing them to be more easily excited. Those well-defined orbitals become sloppier and broader when atoms are able to interact with each other, so photons from the environment can excite more atoms than desired. Now more research will have to be done to test this theory and determine exactly what is happening, and how it could impact Rydberg-based, quantum devices.
Source: Joint Quantum Institute
Posted: March 22, 2016 08:14AM
Silicon has served us very well for in computers for decades now, but it is reaching its limit, so many potential replacements are being investigated. Among these are 2D materials, which could offer tremendous energy savings. Now researchers at ORNL have found a new way to direct-write and edit circuits onto 2D materials.
Currently multi-step lithographic processes are used to etch circuits onto silicon and build computer chips, but these methods have their limitations and disadvantages. What the researchers have done is used a helium ion microscope to manipulate the electrical and structural properties of a 2D material. Normally these microscopes are used to cut and shaper matter, but instead it was used to shape the ferroelectric domain distribution, improve conductivity, and grow nanostructures on bulk copper indium thiophosphate. This means several important properties for this material can be tailored to meet the needs of different applications, while also offering the reduced power consumption and flexibility of 2D materials.
Source: Oak Ridge National Laboratory
Posted: March 21, 2016 09:34AM
Unless you are particularly ruthless at culling and controlling your devices, there is probably a host of applications and apps tracking you and recording the data, possibly to upload to a server. Where that information is stored, whether it is being kept secure, and if it is being shared with other systems is something the user might never know. To at least demonstrate a different infrastructure that puts the user in greater control, researchers at MIT have developed Sieve.
With Sieve, the user uploads their information to the cloud, in an encrypted form, and then whenever an application wants to access the data it needs to get a secret key from the user to decrypt it. To make this work Sieve uses attribute-based encryption and key homomorphism, which are two new cryptographic techniques. Attribute-based encryption applies labels, or attributes, to different pieces of data so that secret keys can be generated for each label, and not the larger dataset. If an app is only asking for your address, the key will decrypt that information, but not your date of birth. Key homomorphism is necessary for scenarios when the user might want to revoke access to the data. This is done be changing the secret key for the data, and key homomorphism allows the data to be re-encrypted without first decrypting it.
Sieve will need app developers to support it before it can be commercially deployed, but in some cases the developers may benefit from this support. This benefit would be from the apps having access to data from other devices, also stored in Sieve.
Posted: March 18, 2016 01:48PM
Letting some sunshine in can really brighten up a room, literally and figuratively, but sometimes you want to block the light for privacy or other purposes. While you could use blinds or drapes to achieve this, in the future you may be able to flip a switch and have the window's opacity change. Researchers at Harvard University's School of Engineering and Applied Sciences have developed just such a tunable window.
The ability to make a window change its opacity is actually not new, but the previous methods used electrochemical reactions and expensive manufacturing processes. This new method works by sandwiching the glass or plastic of the window between transparent, soft elastomers. These elastomers have a coating of silver nanowires, which are two small to scatter light, so the whole package is transparent, until a voltage is applied. This voltage energizes the nanowires, causing them to move together, squeezing the elastomer. Because the nanowires are actually placed unevenly, the elastomer is deformed unevenly, reducing its transparency similar to how smooth ice is clear, but heavily scratched ice is cloudy. Applying different voltages will cloud the window by different amounts, so you can tune them to fit your needs.
By being a physical effect and not chemical, this should off an easier and cheaper way to make commercial tunable windows, as the nanowire layer could be sprayed or peeled onto the elastomer. Now the researchers are working on using thinner elastomers, as these would require lower voltages to work.
Source: Harvard University