Science & Technology News (884)
Posted: April 28, 2015 06:13AM
Since their creation, lasers have proven an invaluable tool for analysis, and that is not going to change anytime soon. With a push towards developing lab-on-a-chip technologies, lasers may become even more useful, in their smallest forms. Researchers at Northwestern University have recently created a nanolaser that is partially liquid and tunable, which would be of great use in various technologies, including lab-on-a-chip devices.
Instead of using a lasing material between two mirrors to stimulate and amplify light of a specific frequency, this new lasers uses gold nanoparticles in a solution. Thanks to plasmonics, the gold nanoparticles concentrate the light around themselves, amplifying it. Plasmonic lasers have been made before, but always with a solid gain material, so this is the first liquid nanolaser. Among the advantages to using a liquid is that the liquid can be manipulated to alter the laser, such as changing the index of refraction to tune the frequency of the laser. This tuning can even be done in real time.
While lab-on-a-chip devices may be one of the best examples of an application for this technology, it could also be used in optical data storage and lithography. All of these applications would likely benefit from how relatively inexpensive the design is and its stability, as the gain molecules can be constantly replaced.
Source: Northwestern University
Posted: April 27, 2015 05:26AM
Securing our data can be very important, especially if that data is something sensitive like credit or medical information. This can be tricky to accomplish though, as many systems are moving to the Cloud, where a user's data may be on the same server as an attacker. Two years ago researchers at MIT designed a way to thwart some of these attacks, and now they have successfully built it into chips, which would make actually deploying it much simpler.
Many people may think that so long as data cannot be read, it is protected, but actually attackers can learn a great deal without ever seeing the data. Instead they can look to what a system does with it, such as how it calls the memory. To secure against such attacks, the MIT researchers developed a technique that calls multiple memory addresses at a time, obfuscating what the desired address was from the attacker. This was accomplished by treating all of the addresses as nodes in a tree, with one node immediately above, and several nodes below. When calling one address, the entire path of nodes from it to the top of the tree is called, and so the entire path is written to as well.
By building this method into hardware, it can be run much more efficiently, but to achieve this, the researchers had to develop some interesting tricks. For example, writing to a path on the tree is difficult to do on hardware, because it would normally require sorting. By adding an extra memory circuit though, the information can be stored there and then written to the main memory once its location has been determined. This writing is also done on only ever fifth read, to further improve efficiency.
Posted: April 24, 2015 02:38PM
Our voices and how we speak are part of how we stand apart from each other, but as we age, these can change. Over time the muscles and tissues involved degrade, leading to weaker or strained voices, but some researchers at the Beckman Institute are interested in finding ways to prevent or reverse this. To that end the researchers have used an advanced MRI technique that allows for detailed images to be captured at an unprecedented speed of 100 frames per second.
There are over one hundred muscles involved with speech, spanning from our chest and neck to our jaw, tongue, and lips. To understand how they all work together and how they change over time, the researchers needed a view inside the human body, while the subject was speaking. Actually the subject was singing 'If I Only Had a Brain.' Obviously the person does, as you can see it in the MRI, and much more. The MRI technique was also developed at the Beckman Institute, and at 100 FPS is significantly faster than any other technique. Typical MRIs operate at around 10 FPS.
Posted: April 24, 2015 05:59AM
Nanotubes are among the carbon allotropes that have piqued the interest of many since their discovery, thanks to their special properties. One of the hopes for these materials is that they can be used to create advanced electronic devices. Now researchers at Rice University have found that some important properties can be tuned for double-walled nanotubes.
Carbon nanotubes are long cylinders of carbon atoms, arranged in hexagons, and come in various forms, include single and multi-walled. Single-walled nanotubes are made of a single cylinder, whereas multi-walled nanotubes are comprised of multiple concentric tubes, and are stronger and stiffer than the single-walled versions. It turns out that double-walled nanotubes exist in a nice place as they have some of the useful properties of single-walled nanotubes, while still being stronger and stiffer. Now the Rice researchers have determined, with atomic-level models, that the properties of double-walled nanotubes can be tuned by manipulating specific properties. For example, the band gap can be controlled by altering the separation between the inner and outer tubes, if the inner tube is semiconducting and outer tube is metallic.
At the moment there is sadly no way to control the growth of double-walled nanotubes with the necessary accuracy, but this research still indicates a great future for such efforts. Also other configurations of nanotubes could have other properties beneficial for various applications.
Source: Rice University
Posted: April 23, 2015 02:28PM
Aerogels are a fun class of materials as they are unbelievably light and have some unique uses, such as collecting dust from a comet's tail. By making them out of different materials, one can get special properties, but some materials are harder to work with than others. Researchers at Lawrence Livermore National Laboratory have recently managed to create an aerogel out of graphene by 3D printing, which is something many have tried and failed to do before.
Aerogels sometimes referred to as 'liquid smoke' and are made by replacing the liquid component of a gel with a gas. Attempts at making one from graphene have more or less failed because the pore structure has been so random, making it impossible to control its mass transport and mechanical properties. The LLNL researchers solved this problem though by turning to a kind of 3D printing called direct ink writing. The ink in this case was an aqueous solution of graphene oxide, mixed with silica, and it was extruded from a micronozzle to form the 3D structure. This allows for the necessary control over pore structure and physical properties.
The resulting aerogel is electrically conductive, lightweight, has a high surface area, and demonstrates supercompressibility. The material could end up finding uses in energy storage, sensors, nanoelectronics, catalysis and separations, and more thanks to the ability to print almost any complex structure desired.
Posted: April 23, 2015 06:50AM
It has been interesting to see how the Internet has changed over the past decade, with social media effectively replacing forums as a means of interacting with others. Despite that change though, forums are still regularly used by many, and are impacting people's lives. That impact may be more than you expect though, as researchers at the University of Exeter have found forum use can significantly improve a user's well-being.
For their study, the researchers surveyed users of forums with stigmatized and non-stigma-related topics, such as mental health issues for the former, and golf for the latter. The survey asked about why people joined the forum, how their expectations were fulfilled, how they identified with other users, their satisfaction with life, and their offline engagement with forum issues. What the researchers found is that those who sought out forums for answers also found them to be sources of support, especially for stigmatizing issues. As the users engaged more, regardless of the nature of the topic, they became more willing to get involved in related offline activities.
As the researchers sum up, by putting more into a forum, the users can get more back. As this also results in more offline engagement and activities, such as volunteering and donating, society can come to be significantly impacted as well.
Source: University of Exeter
Posted: April 22, 2015 02:28PM
Right now billions of neutrinos are streaming through your body, without interacting with any of your cells. Neutrinos are weird particles like that, as they do not interact with much of anything, so we have little knowledge of them. Researchers at MIT, however, may be bringing us closer to determining their mass with a new particle detector.
Many processes emit neutrinos, including the decay of tritium into an isotope of helium. When this happens, a neutrons turns into a proton and emits an electron and a neutron. As the sum of the output must add up to the input, researchers want to narrow down the energy of a single electron to determine the mass of a single neutrino. To that end the MIT researchers have built a particle detector that can pick up the emissions of a single electron. It works by trapping the electron in a magnetic bottle, and then, when the electron moves through a magnetic field, it emits radio waves, which can be used to analyze the electron.
This new detector is small enough to fit on a table top and the area the electrons are tracked in is smaller than a stamp. This in comparison to an advanced spectrometer being used elsewhere that barely fit in city streets. Currently the detector has only worked with krypton, but in a couple years it should be able to move up to tritium.
Posted: April 22, 2015 06:02AM
One day we may be able to say graphene has no secrets left, but that time has not come yet. One of the material's potential uses is for converting light to electrical signals, which could find it applications in cameras, sensors, solar cells, and data communication. Now researchers at the Institute of Photonic Sciences (ICFO) have determined just how fast this conversion process is; under 50 femtoseconds.
Graphene is an atom-thick sheet of carbon atoms that has some special electrical properties, including very fast and efficient interactions between electrons. These interactions naturally come into play with this high conversion speed. When a pulse of light strikes graphene, the researchers found, it causes the electrons to disperse and their temperatures to rise very quickly. This electron heat is converted into a voltage when it comes to the interface between graphene regions with different doping. Thus the effect is actually photo-thermoelectric and occurs almost instantly.
This research could obviously lead to ultra-fast optoelectronic conversion systems, which could be put to use for data transmission, amongst other applications.
Posted: April 21, 2015 02:25PM
As people rely on their mobile devices more and more, we also come to depend on wireless networks. In our homes and on our private networks, bandwidth may not be a problem, but in public places where large numbers of devices may try to connect to the same network, speeds can drop significantly. To help speed things back up, researchers at Oregon State University have developed WiFO, which leverages LEDs for faster transmissions.
Current Wi-Fi networks use radio waves that work well for covering large areas, but have some speed limitations. By shifting to higher frequencies of light, transmission rates can be increased, so many researchers have been working on ways to use LEDs for sending information. The Oregon researchers are using recent advances that allow for faster modulation of LEDs, which is necessary for high speed transmissions, in their WiFO system. The system is more than just LED transmitters though as it is a hybrid system that works across multiple ceiling-mounted LEDs and existing Wi-Fi systems.
Potentially the WiFO LEDs could transmit at 100 Mbps, and as numerous LEDs would be used across an area, each covering about a square meter, users could see 50 – 100 Mbps. Of course devise will need a compatible receiver, which are small photodiodes that cost less than a dollar and could use USB ports on old devices, or integrated into future ones.
Source: Oregon State University
Posted: April 21, 2015 06:13AM
Battery technology is important all over the world, so a great many are working on ways to advance the field. One of the ways of doing this is to change the chemistry involved and move away from lithium ions, to something more potent. This is what researchers at the University of Illinois at Chicago have been working towards, by replacing lithium with magnesium.
Lithium ions possess a single positive charge, which translates to a single electron that a battery can release or store. Magnesium ions though have two positive charges, so a magnesium-ion battery would have double the energy density and power. Actually creating a magnesium-ion battery is not easy, but the Illinois researchers have made an important step by successfully swapping them in for lithium in part of a battery. It is important to show that magnesium ions can move in and out of the electrodes of a battery like lithium ions already do, before a battery can be realized, and that is what the researchers have achieved.
What the researchers have built is still only part of a battery, but it demonstrates the reaction we would find in a battery. Obviously more work needs to be done to reach that goal, but you can believe many are going to take this research and run with it.
Posted: April 20, 2015 02:03PM
Something you may not realize when looking at them is that solar panels and digital cameras operate in very similar ways. Both technologies rely on photodiodes to convert light to an electrical current, but while one uses the current for power, the other measures it for optical information. Researchers at Columbia University decided to combine these two purposes and built a camera that is actually able to power itself.
The camera is housed in a 3D printed body, consists of 40 x 30 pixels, and each pixel is made up of just two transistors. When in operation, the pixels switch between image capture and energy harvesting modes, charging capacitors to provide the necessary power. The researchers could have used a rechargeable battery instead, but opted for capacitors to better demonstrate the self-powered design. If the camera is not set up to record images, it can be used to power other devices.
The hope for this first fully self-powered video camera is to lead to camera capable of running for very long durations, or even forever, as it is not reliant on an external power source. It could also be developed into a compact solid-state imaging chip.
Source: Columbia University
Posted: April 20, 2015 06:04AM
From track pads to touchscreens, touch-based interfaces are around us every day, somehow improving how we connect and use a device. Sometimes our hands are filled though, or cannot reach for our phones or laptops, so some other solution is needed. Researchers at MIT may have come up with just such a solution by building a trackpad the size of a thumbnail.
Named NailO, the device consists of a capacitive sensor and corresponding chip, microcontroller, Bluetooth radio, and small battery. At first the sensor was made of copper electrodes printed onto flexible polyester sheets, but later these were replaced with off-the-shelf sheets already used in some trackpads. All of these were designed to fit on our thumbnail, where a user can comfortable reach and use it. As the thumbnail is hard and lacks nerve endings, it can be affixed and used without causing any discomfort.
Obviously the technology has applications for subtly controlling devices, but it will likely find other uses as well. It really depends on how we decide to interact with devices in the future.
Posted: April 17, 2015 04:38PM
It is certainly true that there are some games in my library that I play just for fun, but there are also some, I would say go farther. Apparently this is not unique to me as researchers at Penn State have come to the same conclusion in a recent study.
The study took 512 gamers and split them into two groups. Both groups were asked to rate their perceptions about a game they played, but as one group had a particularly fun game, the other had a more meaningful game. The two groups agreed the games were fun to play, but those playing the more meaningful game appreciated the experience more.
This finding is probably not that surprising, but may still be important, to show that video games do have a place with other media forms, for giving the consumer a meaningful entertainment experience that is deeply appreciated. Given the interactive nature of video games, the experience could be even stronger, compared to books or movies. While there is nothing wrong with just silly, fun games, this shows that it can be worth it for developers to create the emotional stories and narratives of some games.
Source: Penn State
Posted: April 17, 2015 06:49AM
Never expect anything to be simple in quantum mechanics, but then somethings in classical mechanics can be very complicated as well. Temperature is one such example as that simple value describes absurdly complex and chaotic activity. Researchers at the Vienna University of Technology have at long last succeeded in studying how gases behave with temperature, when their quantum properties are brought out.
The molecules in the air around us are zipping around and bouncing off of each other and other objects so much that it would be impossible to track them all, but luckily scientists do not have to, in order to describe them. Instead they rely on statistical physics to determine the properties of the entire gas, but this has led to the question of how one gets from statistical mechanics to quantum mechanics. To answer that, the Vienna researchers used a microchip to catch and cool several thousand atoms to a little above absolute zero, to bring out their quantum properties. By manipulating the chip, the quantum gas could be manipulated as well, and the researchers found the gas could take on multiple temperatures at the same time. Though predicted, this behavior has never been observed before.
For now this research should lead to an improved understanding of quantum mechanics and its relationship to thermodynamics. Someday it may lead to new technological applications as well as how our classical laws of physics emerge from those of quantum mechanics.
Posted: April 16, 2015 02:14PM
One of the many uses of machine learning is computer vision, whereby a computer analyzes a scene and identifies the objects in it, without them exactly matching known models. Building these algorithms can requires thousands of lines of code, but some are turning to probabilistic programming languages to simplify the work. In the case of the Picture language MIT researchers developed, those thousands of lines can be simplified to less than 50.
Probabilistic programming differs from deterministic programming by being based more on inference, which fits well with machine learning. Instead of requiring very specific descriptions, programmers can describe a vague model that the program runs through inference schemes to solve, using inverse-graphics reasoning. The MIT researchers have tested Picture by giving it the simple description of the human face as having two symmetrically placed eyes, with the nose and mouth positioned beneath them. Armed just with that knowledge and examples, the program was tasked with working through 2D images to construct 3D models, and was able to match the thousand-line programs, and in some cases surpass them.
Technically more code than 50 lines is involved behind Picture, as it draws on multiple inference algorithms, but the model for the task itself is still much simpler. This is actually one of the purposes of probabilistic programming languages, where the language is generic and can be used with many inference algorithms, depending on the task.
Posted: April 16, 2015 05:53AM
One day we may see the construction of a quantum Internet that will be far more secure than today's global network. This is thanks to quantum encryption, which protects data from being read and alerts users to eavesdroppers. For it to work though, we need the ability to transmit photons in a quantum state over great distances, and researchers at the University of Toronto have designed a technology to help with that.
Even modern optical communications require repeaters to ensure classical signals survive their travels, so more fragile quantum signals need special repeaters to preserve the information. The current technology for doing so is complicated, acting like a mini quantum computers, requires low temperatures, and is kind of slow. What the Toronto researchers have created is an all-photonic quantum repeater that comes with several benefits. Just by being all photonic the system is much simpler, as it no longer requires a physical quantum memory system, or an interface between matter and light. It is also able to operate at room temperatures, has a higher communication rate, and a superior fault-tolerance.
One aspect to this design that is particularly interesting is that its components have already had proof-of-principle demonstrations made. This work started as an attempt to transmit polarization over long distances, but then the researchers decided to try for the 'fancier' quantum teleportation, which teleports the entire state of a particle from one location to another.
Source: University of Toronto
Posted: April 15, 2015 02:26PM
People have been fascinated with the idea of invisibility for millennia, but only in modern times may we actually achieve it. Metamaterials are man-made materials with properties impossible to find in Nature and can be used to cloak objects. As it turns out though, there is a simpler way of achieving invisibility, and researchers at ITMO University, Ioffe Institute and Australian National University have done just that.
What the researchers have done is take advantage of a classical problem concerning the scattering of light from a homogeneous sphere that was solved almost a century ago. When light strikes an object of high refractive index it can scatter by two mechanisms: resonant and non-resonant scattering. Instead of a sphere, the researchers were working with a glass cylinder filled with water, which they change the refractive index of by changing the water's temperature. By doing this correctly, the resonant and non-resonant mechanisms scattered waves of opposite phases, causing them to cancel each other out, making the object invisible. This was achieved for microwaves at 1.9 GHz and by changing the temperature of the water from 90 ºC to 50 ºC.
Though the current work dealt with microwaves, it could be applied to the visible spectrum of light. It could also have applications for the development of nanoantennas, such as building invisible support structures. As these structures would not need special, metamaterial coatings, they would be much simpler to make.
Source: ITMO University
Posted: April 15, 2015 05:56AM
Humans have been looking to the sky for probably as long as we have had eyes, and there are still many mysteries to solve. Among these is dark matter, a source of gravitational force that may have a link to galaxy formation and the continued existence of galaxies as well. Now researchers at the European Southern Observatory have found dark matter interacting with itself in an unpredicted way.
Nobody knows what dark matter is, but we do know we cannot see it. That is not the reason we refer to it as being 'dark' though, or at least it is not the only reason. It is also called dark because it does not interact directly with normal, light matter, which also interacts with light. It even seems that dark matter does not interact with itself, except through gravity. The only means we have to observe dark matter is by the bending of light its gravity causes as light travels through the Universe. The ESO researchers looked to a collision of four galaxies and mapped the distribution of dark matter in the collision, finding one clump of it lagging behind the galaxy it surrounds. The amount of lag cannot be described by gravity though, which means there must be some other force involved. Whether that force is something we already know or something completely exotic can only be determined with more research.
This research nicely pairs with that of another team looking at collisions of galaxy clusters, which also indicated that dark matter interacts with itself. Together these studies put brackets on the behavior of dark matter, and eventually we may be able to squeeze down to whatever dark matter really is.
Posted: April 14, 2015 02:03PM
Currently our computers rely on the charge of electrons to operate, but in the future computers may use electron spin instead, as it offers many benefits. Often these two properties seem to be kept separate, but by combining coupling these properties we can develop spin-orbitronics. Devices based on this field can be smaller, faster, and more energy efficient and researchers at Berkeley Lab have made a discovery to bring them closer to reality.
Central to many of our computers and the Internet is magnetic data storage, which relies on magnetic domains in magnetic films. What the Berkeley researchers have found concerns the walls between these domains and how they react to electrical currents. Within magnetic domains all of the spins of electrons are aligned either up or down, but the walls between them can be much more interesting. These walls can have spins that rotate in a helical spiral or in a cycloidal spiral, and either can have right or left-handed chirality. When a current runs through them the walls, depending on their spin, can be propelled with the current, against the current, or to the left or right. The researchers also found that the handedness of the walls can be flipped by controlling the strain on the film.
Spin-orbitronics could open up new ways to store data in magnetic memory devices. This would include storage devices that rely on electrical currents, instead of mechanical systems to retrieve data.
Source: Berkeley Lab
Posted: April 14, 2015 05:30AM
It is hard to say exactly when, but eventually we are going to have quantum computers capable of quickly performing operations even the best modern computers cannot. Much needs to be done before then though, both in terms of developing new technologies, and refining them to be easily produced. Researchers at the University of New South Wales have recently achieved both by successfully altering a qubit inside a silicon chip with an electric field.
Qubits, or quantum bits, are what quantum computers rely on, and unlike electronic bits that stores zeroes or ones, qubits are capable of representing both zero and one at the same time. This is thanks to the quantum mechanics phenomenon known as superposition. Manipulating qubits is somewhat challenging, in part because of how fragile they are, but the New South Wales researchers were able to control one using electric fields. The qubit was actually a phosphorus atom within silicon-28, an isotope of silicon that is completely non-magnetic and does not disturb the qubit. Normally manipulating such a qubit requires pulses of oscillating magnetic fields.
By achieving control over single qubits with just electric fields, a quantum computer could be made much more cheaply, by using voltage generators instead of high-frequency microwave sources. Also the manufacturing process needed to produce the qubit is similar to that used to create computer chips, further reducing costs.
Posted: April 13, 2015 02:27PM
Efficiency has always been a priority when it comes to designing electronics, and with today's nanotechnologies, the ways to achieve it are more becoming much more advanced. Researchers at the University of Texas at Arlington have been awarded a $300,000 grant from the NSF to work on a new transistor design that could improve efficiency by a factor of ten.
This new transistor design is quite different from traditional designs as all of the components are contained in a single nanopillar, less than 50 nm in diameter, and arranged vertically, so they can still be packed in on a chip. Besides its geometry, the transistors are also special because the electrons can flow through them without heating up. This is achieved by passing the electrons through a quantum well, which will cool them down to -228 ºC at room temperature, and without special external means. By keeping the electrons cool, the transistors can operate with less energy, and of course generate less heat. The results would be longer battery lives and/or lighter loads to carry.
Source: University of Texas at Arlington
Posted: April 13, 2015 06:23AM
For any scientific endeavor, you must have accurate measurements because without them a slew of calculations can be thrown off or produce incorrect results. A research team, led by researchers at the University of Arizona, has discovered that certain cosmological measurements are inaccurate, and that our understanding of dark energy may be off.
For a long time it was believed that the size of the Universe was constant, and then it was determined to be expanding, but today we know the expansion is actually accelerating. The exact cause of this acceleration is not known, but has been given the name dark energy. It was discovered by measuring the light emitted by type Ia supernovas, which are explosions of white dwarf stars, throughout the history of the Universe, and comparing their brightness. It has long been believed that this type of supernova is constant and thus always produces the same light, thereby allowing them to act as cosmic candles. What the researchers discovered is that these supernovae are not as constant as believed, as one looks back in time. Instead the researchers found that two distinct populations exist, with those nearer to us being more red than those farther away, from when the Universe was younger.
This discovery was only made possible thanks to the ultraviolet capabilities of the NASA Swift satellite, as the differences in visible light are much more subtle. The researchers found this different both in their own datasets and in others. The exact implications this discovery may have on our understanding of dark energy and astronomy are not yet known and will require a great deal more data to determine.
Source: University of Arizona
Posted: April 10, 2015 02:24PM
Whether it is hot or cold, heat transfer is important to us and in most cases it is well understood. For situations are covered by convection, conduction, or radiation, but at the small scale of a nanometer or less, things get harder to explain. That has changed now, thanks to researchers at MIT who have found that quantum tunneling can explain how heat can jump the gap.
When discussing heat at small scales, phonons must be part of the conversation as they are the energy units for vibrational energy and heat. Exactly explaining how phonons move has been a challenge for a long time now, as some theories skip over what happens at the atomic scale and others have obvious flaws to them. To find the solution, the MIT researchers turned to the microscopic Maxwell's equations, which are a form of the better known Maxwell's equations that govern electricity and magnetism. When these were applied the researchers found that phonons could actually tunnel across gaps between objects separated by just one nanometer or less. Tunneling is a quantum mechanical phenomenon where a particle or wave will skip over, or tunnel through a barrier it normally should not be able to.
With this answer, we have a more complete understanding of how heat flows, as now that understanding finally reaches to the nanoscale. It of course has practical applications wherever heat transfers, especially at very small scales.
Posted: April 10, 2015 06:30AM
If you heat a magnet up enough, it will lose its magnetism, but cooling a magnet should not remove that property. For some materials however, magnetism does disappear at temperatures near absolute zero, and these are called frustrate magnets. Due to this lack of magnetism, many believe that the Hall Effect, which relates to magnetism, would not exist at these temperatures, but some thought otherwise, and now researchers at Princeton University have confirmed it.
The Hall Effect is the deflection of a current of charge carriers, electrons, in a conductor by an external magnetic field. As a frustrated magnet contains neutral, non-charged particles at low temperatures, the Hall Effect seemingly would not work, but at these temperatures quantum mechanics reigns and expectations can mean very little. To test this, the researchers needed a frustrated magnet, to cool it to 0.5 K, and to be able to resolve temperature differences between opposite edges of the crystal. It was not easy to achieve, but the researchers succeeded and put a heat current through the crystal, which is analogous to an electrical current at these temperatures. When they then applied a magnetic field perpendicular to the current, they observed the current deflecting, just like the Hall Effect would suggest.
This research opens up some interesting possibilities, including potentially a new understanding of high-temperature superconductors. Some of these materials may rely on a particle called the spinon, the proposed carrier for heat currents in quantum systems, and this research may lead to a means of discovering it.
Source: Princeton University
Posted: April 9, 2015 02:00PM
One of the many challenges when it comes to cancer is finding circulating tumor cells (CTCs) in a blood sample. Traditional methods involve using special antibodies and centrifuges that run for ten minutes. Researchers at Penn State though have developed a much simpler technique that utilizes sound waves to separate cells at a rate better than 83%.
The new technique exploits the fact that sound waves are pressure waves, which means they can exert a force to move small objects, like cells and nanoparticles. The researchers worked with an acoustic-based microfluidic device, which allows blood to stream through continuously, and applied sound waves of the same frequency to both sides. This creates an area where the sound waves from the two sources cancel out, so an object pushed along by the waves will stop in that area, and continue flowing through the device, but separated from other, different particles. The researchers optimized the procedure to separate HELA and MCF7 cells, and achieved a separation rate better than 83%, and when they tested it with other cancer cells achieved the same better than 83% rate.
Obviously this could greatly help with the treatment of cancer by allowing for a simpler, faster, and cheaper process to identify cancer cells in the blood. Some more work is definitely needed though, such as finding how to mass produce these devices, so they can be disposable after having touched human blood.
Source: Penn State
Posted: April 9, 2015 06:46AM
There are several antennas in various devices surrounding me at the moment, and while we have understood how many of them work for over a century, some of them have been a puzzle. Specifically those antennas made from insulators, instead of conductors have been a mystery since their discovery. Researchers at the University of Cambridge have found the answer though, and the discovery has great potential both for practical devices and our understanding of physics.
Maxwell's equations explain how accelerating electrons generates electromagnetic radiation, which makes sense in conductors, but in dielectrics that restrict electrons from moving, another explanation is required. To do their work, the Cambridge researchers used thin films made of piezoelectric materials, which will physically deform or vibrate, when exposed to a voltage. At certain frequencies though, they become very efficient resonators and radiators of EM radiation. From this they were able to determine a link to symmetry breaking of the electric field. Accelerating electrons already breaks the symmetry of an electric field, but by applying asymmetric excitation to the thin films, the researchers were able to cause similar breaking, and thus generate EM radiation.
With this understanding, it may be possible to make ultra-small antennas, and potentially integrate them into computer chips. It also may provide a missing link between electromagnetism and quantum mechanics, which would lead to even more possibilities.
Source: University of Cambridge
Posted: April 8, 2015 01:59PM
Chances are we will never stop demanding faster devices, even if physics prevents some technologies from giving us those increases. Naturally then, other technologies need to be developed, which is why some, like plasmonics, are being worked on. Plasmons can provide the best of both electrons and photons, and now researchers at NIST have created a device that could help bring plasmonics to future computers.
Plasmons exist as a coupling of light and electrons, allowing the information of the light to be carried on metal wires far smaller than a photon could fit in. What the researchers developed is a plasmonic phase modulator, which acts like a speed bump for plasmons, though it is inverted. It consists of eleven strands of gold spanning 23 micrometers, positioned 270 nanometers above a gold surface below them, with the plasmons traveling through the gap between them. When a voltage is applied, the gold strands will bend down, toward the gold surface, constricting the plasmons and slowing them down. This also shortens their wavelength, potentially allowing another half plasmonic wave to enter at maximum voltage, which could be used to selectively cancel out the plasmon wave.
This ability to cancel out the waves means that the device can act as an optical switch, which would be of great use in plasmonic devices. Currently the prototype is pretty large, compared to modern electronics, but according to their calculations, it could be scaled down by a factor of 100 without increasing optical loss.
Posted: April 8, 2015 06:31AM
Batteries are an essential technology for modern life, which is why so many are working on ways to improve them. Potential improvements include ways to reduce cost and accelerate their charging, amongst many other goals. Researchers at the University of Houston appear to have succeeded with those two when they discovered how to create an N-doped polymer.
For quite some time now, researchers have been interested in electrically conductive polymers. What the Houston researchers found is that naphthalene-bithiophene can be doped with lithium ions, making it very conductive, and will remain stable and reversible for thousands of charge/discharge cycles. This is a pretty big deal as polymers are much cheaper and easier to produce than the materials needed in conventional, in-organic batteries. The polymer has previously been used in solar cells and even as transistors, but this is the first time anyone has made a battery from it.
Currently, modern in-organic batteries can still store more energy, but the organic battery has them beat in charging rate as it reached 80% in just 6 seconds, and was fully charged after another 18. The researchers are going to continue to work on the polymer and try to learn more about it.
Source: University of Houston
Posted: April 7, 2015 04:07PM
Gyroscopes are used in a variety of places for measuring movement, and without them many vehicles, like rockets and satellites, would not be able to guide their flights as necessary. Especially in those two examples, it is very important to keep size and weight down to a minimum, but accuracy also cannot be sacrificed. As published in The Optical Society's journal Optica, researchers have developed a new optical gyroscope that is the world's smallest, at just microns across.
Optical gyroscopes are not a new technology and operate very differently from the classic gyroscopes we have probably all encountered in school. Where those gyroscopes rely on Newton's laws, optical gyroscopes use the Sagnac effect, which describes a color shift when light splits and recombines as it exits a spinning system. The problem has been that both of the two basic designs, using either an optical cavity of optical fiber, have degraded performance as they are made smaller, so as much as six kilometers of optical fiber may be used. The researchers got around that though by changing what they were looking for. Instead of trying to sense a change in color, they instead watched for the small, but still measurable relativistic effect of rotating a light source bending spacetime. The resulting distortion can then be analyzed to determine the speed the cavity was rotating at.
By bringing the size down to potentially just 10 microns across, this new optical gyroscope design could be fit into a number of technologies, and integrated into optical circuit boards. More work needs to be done though, to take different optical modes into consideration and to enable measurements of full 3D movement.
Source: The Optical Society
Posted: April 7, 2015 06:59AM
Battery technology is a big deal as so much of our life uses devices that rely on them, in one form or another. While we may rely on them, there are some aspects to these batteries we dislike, such as slow charging speeds and potential safety hazards. Researchers at Stanford University may have developed a solution though by creating a rechargeable aluminum battery.
Aluminum is actually the most common metal on Earth, so it is very cheap, and because it has great potential for storing electrical charge, many have tried to make a battery with it before. One of the challenges preventing these batteries from existing has been the search for materials to produce a useful voltage from such a battery. The Stanford researchers were lucky in that regard as they accidentally found that a simple solution of graphite could act as a very effect cathode. They then built a prototype battery consisting of an aluminum anode, graphite cathode, and liquid electrolyte, all inside a flexible polymer-coated pouch. This design has many useful properties to it, including the electrolyte being liquid at room temperature and the components not being flammable, unlike lithium ion batteries. In fact the researchers drilled a hole through the battery, and it still functioned, and were also able to bend and fold it, while it worked. Besides these mechanical properties, the prototype battery can also be charged in just a minute and survive 7500 cycles before losing capacity. Lithium-ion batteries tend to last about 1000 cycles, for comparison, and previous aluminum batteries only survived about for 100.
While there are definitely more than enough properties to warrant further research into this technology, it does still have one significant flaw. The aluminum battery can match and exceed the voltage of AA and AAA batteries, but comes to only half that of a lithium-ion batteries. The researchers believe that improving the cathode can raise the voltage and energy density enough to compete with modern batteries.
Source: Stanford University