Science & Technology News (524)
Posted: August 21, 2014 06:24AM
In many cases, electricity is generated by driving turbines with one fluid or another, such as steam or water. What can really set power plants apart is what puts the energy into the fluid that the turbines extract. One new method may use salt for that purpose, and researchers at MIT have found that such a system is not as simple as believed.
If you have two fluids with different solute concentrations separated by a semi-permeable membrane, such as having saltwater on one side and fresh water on the other, the fluids will move to try to equalize the concentrations on both sides of the membrane. The motion of the fluids is called osmosis, and pressure retarded osmosis (PRO) is a process some have been investigating for producing electricity. The idea would be to put pressurized salt water on one side of a membrane and fresh water on the other, and use the movement of the fresh water through the membrane to turn a turbine. What the MIT researchers have discovered is that the efficiency of a PRO system is more complicated than previously thought. According to their new model, the optimal membrane size is not the maximum membrane size, as a membrane half the area could produce 95% of the maximum output power.
Potentially PRO systems could be used to power desalination plants and water treatment plants, by putting saltwater or brine on one side of the membrane, and fresh or waste water on the other. To completely power some treatment plants may require some of the largest membranes in the world, but new configurations are being developed to fit the millions of square meters in relatively small packages.
Posted: August 20, 2014 02:06PM
Though we may not think about it much, we are all aware of Earth's magnetic field. The most obvious use of it is to orient compasses, but it has other uses too, as it is used for probing in geology and archaeology. Thanks to researchers at Berkeley Lab, it may soon also find use for analyzing chemical compositions of fluids, without removing them from their native environments.
Nuclear Magnetic Resonance (NMR) is a phenomenon that can be used to determine the materials in some sample, and possibly its most common use is medicine's MRI machines. It works by measuring how atoms behave when the angle of their spins are manipulated. Normally strong and uniform magnetic fields are used, but these are not always available. What is always available on Earth though is the planet's magnetic field. Attempts have been made before to use the Earth's magnetic field for NMR, but failed because the field is so weak and the equipment was not very sensitive. The Berkeley researchers have discovered that it appears to be possible now, by using highly sensitive optical magnetometers and by looking at how the spins of molecules relax and diffuse.
Potentially this technique could be used to characterize the contents of solids underground, such as in oil wells, and actually measure hydrocarbons and water within rock, as well as inspecting the curing process of polymers and cement. The researchers next want to increase the depth their method can reach inside of a material, possibly piercing a meter or more, instead of the inches possible with current technologies.
Source: Berkeley Lab
Posted: August 20, 2014 09:39AM
Many modern solar cells are made of materials like silicon and are expensive to produce. In the future though, new photovoltaics based on polymers could replace them by being cheaper and more resilient. Finding the right polymers is tricky though, but researchers at the University of Tsukuba and Nation Institute for Materials Science have found a way to speed up the search, as published by the American Institute of Physics.
Materials science can be an exhaustive field as the materials would be to be produced for testing, and only then could it be determined if the materials is of much use. By better understanding the behaviors of a material, it is easier to predict its properties and thereby speed up the process. This is what the Japanese researchers have accomplished for candidates for organic photovoltaics by combining two kinds of photo-induced spectroscopy. The two processes important for these materials are their charge formation and charge transport efficiencies, and it is believed that the charge formation efficiency is complicated and actually dependent on a thermal activation process. What the researchers discovered is that the temperature actually does not matter, as samples demonstrated the same efficiency at 80 K and 300 K.
This discovery indicates that the charge formation efficiency for organic photovoltaics is only quantum mechanical, which actually makes it simpler than expected. The result is that it should also be easier to quickly screen materials by this property, and in turn speed up searches for new organic photovoltaic materials.
Posted: August 20, 2014 05:57AM
More and more, fiber optic cables are being installed for carrying information across networks and across the Internet, because they are great speed and capacity. Many would like to see fiber optics enter our computers as well, but shrinking the cables has been proving difficult. Researchers at the University of Alberta though, have managed to create nano-optical cables that could enter our computer chips.
Presently copper wires are used within computer chips as interconnects, because the metal does a decent job. Optical fibers could do better, but their diameter has been limited to the micrometer range, which is too large. By turning to metamaterials however, the Alberta researchers were able to go an order of magnitude smaller, without losing data, slowing the signal, or creating heat. As you can no doubt guess, bringing fiber optics into chips would also bring significantly greater speeds and efficiencies than what we see now.
Source: University of Alberta
Posted: August 19, 2014 02:09PM
One of the biggest challenges with quantum computers is finding a way to store quantum information for extended periods of time. There are many different approaches being studied right now for preserving the information, and each has its own advantages and disadvantages. Now researchers at the Vienna University of Technology have combined two of these techniques and managed to extend the stability of the information.
One of the techniques being developed encodes the quantum information onto nitrogen atoms inside of diamonds, which protects them from external forces. Another technique encodes information onto photons trapped in a resonator. The researchers have combined these two concepts by using a microwave resonator to encode information onto multiple nitrogen atoms. This actually keeps the quantum information coherent for longer than it would normally by causing all of the nitrogen atoms to be coupled with the resonator. This mass coupling prevents the atoms from losing coherence, keeping the quantum information accessible for longer.
By opening the door to hybrid quantum technologies this way, it is hard to predict what new technologies may be created in the future. Of course quantum computers will see a benefit, but the potential of this research could be greater than longer memory storage.
Source: Vienna University of Technology
Posted: August 19, 2014 11:40AM
Unless you are exceptionally careful about what information is on the Internet, there is a good chance you have been presented with a recommendation based on your online activities. Of course we all know that services and websites collect information from emails, video views, and product views, but how exactly do they generate the recommendations? That is what researchers at Columbia University want to know, and so they have developed XRay to provide greater transparency on the Internet.
Approaching the problem of how our information is used is tricky, because much of the Internet operates like a black box. Without the ability to view the processes involved in generating the recommendations, XRay has to rely on black-box correlations between inputs and outputs. At first the researchers worked with theoretical results, which were encouraging, but only theoretical, so they soon started running experiments on Gmail, Amazon, and YouTube and refining the design. Eventually XRay achieved complete success with each experiment, matching theoretical predictions in complex cases, which suggests it can scale up well.
Though the current system has only been run on Gmail, Amazon, and YouTube, it should be service-agnostic, so any site that tracks you could be studied with XRay. Thus far it has revealed that it is possible to target sensitive topics and that there does appear to be abuse of the recommendation systems. You can see examples results at XRay's website: XRay: Transparency for the Web.
Source: Columbia University
Posted: August 19, 2014 06:36AM
Lead has quite a history as the soft metal once saw many uses, such as water pipes to additives for gasoline and paint, but is now restricted to just a few, due to its potential health hazards. That is also why we see so many recycling programs specifically for lead, to keep it from getting somewhere it should not, and to reduce the amount that needs to be acquired. Now researchers at MIT have devised another recycling program that could see lead repurposed for use in solar cells.
Perovskites are a family of compounds that share similar structures, and organolead halide perovskite is being looked at for use as solar cells. Some of these cells have already exceeded 19% efficiency, which makes them almost competitive with the silicon-based solar cells you can find today. The catch is the use of lead, especially as the solar cells would require more lead to be mined. The MIT researchers however have developed a process to take the lead from car batteries and use it for solar cells. As the lead compound would actually be a thin film, they predict that the lead of a single car battery would be enough to make enough solar panels to power 30 homes.
Along with providing another reason to recycle car batteries, this could also help bring the cost of solar cells down. The process is low temperature and requires fewer steps than conventional solar cells to produce, making it potentially easier to scale up cheaply.
Posted: August 18, 2014 01:57PM
Many people likely associate the image of a table covered with beakers, flasks, burners, and at least one microscope with a chemistry laboratory, but that is likely to change in the future. Many groups around the world are working on creating lab-on-a-chip systems that will condense chemical testing equipment onto something the size of a computer chip. Researchers at the University of California, Santa Cruz have recently created a chip with the ability to identify single molecules by combining electrical and optical measurement techniques.
The chip utilizes a nanopore that acts as a smart gate, to control the flow of molecules into a channel. The nanopore also allows the researchers to make electrical measurements as the molecules crosses it. For DNA passing through the nanopore, the electrical measurements would actually be able to determine the genetic sequence of the DNA, by fluctuations of the current. Once in the channel, the molecule is also exposed to a beam of light, and changes to the light's intensity indicates the size and optical properties of the molecule, as well as the flow speed through the channel.
When the researchers tested their chip with a mixture of influenza viruses and nanobeads of similar diameter, tagged with fluorescent labels, they found that they were able to distinguish between the two particle types using their electrical and flow properties with perfect accuracy. They were even able to count the number of virus particles, which would be very useful for analyzing samples.
Posted: August 18, 2014 08:40AM
Some people may not always think about it, but impurities are important to our way of life. The changes impurities can cause in many materials has enabled and improved many technologies we have come to rely on. Now researchers at Rice and Osaka universities have found how much impurities can disrupt graphene, a material many hope will be central to future technologies.
Graphene is an atom-thick sheet of carbon with special electrical properties, including great electron mobility. Of course for those properties to be useful in future technologies, they must persist, but the researchers have found that they can be greatly affected by impurities from the environment. The researchers grew a sheet of graphene and transferred it to an indium phosphide substrate for this research. When femtosecond laser pulses struck the graphene, the indium phosphide reacted by emitting terahertz radiation that passed through the graphene. Using a spectrometer, the researchers were able to detect imperfections as small as an oxygen molecule, as they affect the electric field of the graphene, and disrupted the terahertz radiation.
Of course the knowledge of how much graphene can be affected by imperfections is going to impact the development of technologies that may use it. One potential technology may be to actually adapt this experiment's design as a highly sensitive gas sensor.
Source: Rice University
Posted: August 18, 2014 05:30AM
Graphene is an amazing material with its special mechanical, electrical, and optical properties, making it of key interest to many. The hope is to one day use it in a variety of devices such as advanced sensors and higher speed and efficiency electronics. Now researchers at the National Physical Laboratory have discovered that the edge of graphene has some interesting properties that could influence some future applications.
One of the main reasons graphene is studied so much is that electrons can move along it at great speed and with little resistance. Such electron conduction would be very useful for many devices, but the NPL researchers have discovered that the edge of graphene conducts differently. While the bulk of the plane conducts electrons, the edges instead conduct the positively charged holes left behind by excited electrons. Effectively this makes the interior of a graphene sheet n-doped with the edge p-doped, and while both can conduct electricity, the differences are important for designing devices.
With side-gates the researchers were able to tune the conduction of the edges without affecting the center. The researchers also discovered that the differences in conduction were most pronounced after the graphene had been cleaned, but faded over time, suggesting it is the result of defects that were filled by airborne molecules.
Source: National Physical Laboratory
Posted: August 15, 2014 02:00PM
Normally one would expect that an object can be described as the sum of its parts, depending on what specific property you are describing. For protons, many believed that their spin was the combination of the spins of the particles that make it up, but in the 1980s experiments showed this was not the case. Since then researchers have been working to solve the proton spin crisis, and those at MIT have some new evidence.
According to the standard model, protons are made of two up quarks and one down quark, which do add up to the positive charge of the larger particle. Adding the spins of the quarks up does not result in the spin of the proton though, so researchers have been searching for where the additional spin must come from. One theory is that the bonds between the quarks occasionally break, and this allows pairs of quarks and antiquarks to briefly appear and annihilate, contributing to the proton's spin while they exist. To test this, the researchers collided a number of protons, which produced some W bosons. These bosons would have the spin of any antiquarks that were present when the proton collided, thereby allowing the researchers to determine how great an influence the quark-antiquark pairs have on proton spin.
As it turns out, the spin of the antiquarks is only marginal and not enough to solve the crisis. All is not lost though, in a larger sense, as the information collected gives a much better understanding of how up-flavored antiquarks behave and come to exist. This will aid future studies into the crisis as well.
Posted: August 15, 2014 09:20AM
Several years ago, NASA's Stardust mission took to space to collect particles from a comet's tail and possibly interstellar dust, before sending them back to Earth. There have already been many studies published about the particles from the comet's tail, but we are only starting to see analyses done of the much more special interstellar dust grains. Among those institutions studying the dust is Berkeley Lab.
While on its way to the comet, Wild 2 the Stardust spacecraft exposed its collector to space, with the hope of catching some dust particles that may be from outside the Solar System. As you can guess, such particles would be very rare and would provide unique insight into our little corner of the galaxy. To that end, the researchers have examined seven grains that may be interstellar dust using non-destructive techniques. Three of these were found in the aerogel while the other four left pits and residue on the aluminum foil. The two larger grains found in the aerogel surprised the researchers as they had a fluffy composition, like a snowflake, which is counter to the expectation of interstellar particles being dense. They also contained the mineral olivine, which would suggest they came from the disks or outflows of other stars. Three of the particles found in the foil contained sulfur compounds, which are not believed to exist in interstellar dust. Further study will be needed to explain the presence of these compounds.
While the current analyses of these grains will prove very informative, the most important examinations are still in the future. Those are to determine if these grains are indeed from outside the Solar System, but as the experiments would destroy the precious grains, tests are being done on analogs first.
Source: Berkeley Lab
Posted: August 15, 2014 06:15AM
One of the many interesting phenomena in Nature is swarming, whereby individual organisms, like ants, cells, and fish, will act together to achieve something no single individual could. This behavior is something many have been trying to replicate with robots, as a means to improve their effectiveness and to test their AI. Researchers at Harvard University have recently created the first thousand-robot swarm and gotten it to form human-specified shapes.
The swarm consists of 1024 robots called Kilobots, for obvious reasons, and each of these devices are just a few centimeters wide and stand on three thin, rigid legs. Two vibrating motors are used to get the robots sliding over a surface while infrared light is used for communication. This simple design kept the robots cheap, but also increased the chance of errors, but fortunately the algorithm driving them is smart enough to detect and actually correct the errors. In fact the algorithm has been proven to allow the robots to complete the task given to it. To get the robots started, they are given the image to recreate and four are then used to designate the origin of the image. Next the arbitrary mass of Kilobots starts moving one by one along the edge, until they reach the next point to fill in the image.
This is the first time a swarm consisting of a thousand robots has been tested and is an important milestone for distributed robotics. In the future we may see robots swarms being used for cleanup, rescue efforts, and even as chauffeurs as self-driving cars would be an example of distributed robotics.
Source: Harvard University
Posted: August 14, 2014 03:20PM
Carbon and silicon share many properties because they are in the same family of elements. This also means that the structures one element can form, the other likely can as well. Silicene is the silicon equivalent to graphene and now an international team of researchers has successfully demonstrated its stability in open air, as reported by the Institute of Physics.
Like graphene, silicene is an atom-thick sheet of silicon atoms in a hexagonal pattern, but it is tricky to make and can be destroyed by oxygen. To grow silicene, a silicon wafer has to be heated in a vacuum chamber, so the silicon atoms can come off of the wafer and deposit on a substrate, typically silver. If too many layers of silicene stack up, the material will degrade back into silicon, which is a more stable structure. Also if it is exposed to oxygen, the formation of the layers can be destroyed. The researchers however successfully built up 43 layers of silicene and exposed it to open air for a full day, before it degraded. It appears the oxygen in the air did react with the top layer to form a thin oxidation layer, which actually protected the stack.
The hope is that one day silicene and other 2D forms of silicon will be used in electronics. In particular the material may be used to create silicene-based MOSFETs.
Source: Institute of Physics
Posted: August 14, 2014 09:24AM
A classic technology of science fiction is the tractor beam, which by some means is able to hold and move a remote object without directly touching it. Such functionality has been reproduced optically, but that only works on relatively small objects. Now researchers at the Australian National University have discovered that it is possible to create a tractor beam using water waves quite easily.
Normally one would expect that water waves would push objects away, or leave them where they are. At certain amplitudes and frequencies though, the researchers found that the ping pong ball they were testing with would move against the waves. According to advanced particle tracking tools, the waves were generating flow patterns on the surface of the water that would move the ball around. Different patterns would result in different movements.
Presently, there is no mathematical theory to explain these observations, but we can already envision applications. This could be used to manipulating floating objects and even trap and confine oil spills to certain regions.
Source: Australian National University
Posted: August 14, 2014 06:02AM
Though some may find it disgusting, sweat is a useful material as performs a necessary for regulating body temperature. It also contains compounds that can provide information about a person thanks to some new research, as reported by the American Chemical Society. The researchers went farther than just creating a sensor though by building a biofuel cell powered by sweat.
When people exercise, the body needs energy to fuel its muscles, and for particularly strenuous activities it activates glycolysis. This process produces the needed energy as well as the compound lactate, and by measuring the amount of lactate, a doctor can determine the person's fitness. Traditionally making these measurements required taking blood samples, but the researchers discovered a way to actually measure it in sweat using electrochemistry. The sensor, which has been built into a temporary tattoo, actually pulls electrons off of the lactate molecule, creating a weak current, and measuring the current provides information on the amount of lactate. The researchers then took another step by adding a small biobattery to the device to current useable energy.
When tested on people of different fitness levels, the researchers found the least fit people produced the most lactate, which makes sense as their bodies are activating glycolysis earlier than more fit people. The maximum current was still only about 70 micro-Watts per cm2, or 4 micro-Watts, which is not much, but the researchers are confident they will be able to increase that with more work.
Source: American Chemical Society
Posted: August 13, 2014 02:15PM
If we lived in a perfect world, waste products could be easily converted into something useful, but thanks to the laws of chemistry and physics, that is not how things work. Reactions the produce energy also produce waste products that are more stable than the reactants, to changing them back is a difficult process. Researchers at Brown University though have found that copper foam could be used as a catalyst to convert carbon dioxide into more useful chemicals.
It has already been demonstrated that copper is the best choice of catalyst for reducing CO2 into more useful hydrocarbons, but it is not always that efficient at it. One way to improve it is to use a rough copper surface, as this creates more sites for the chemical reactions to occur. The Brown researchers investigated how well copper foam, which was only developed in the past few years, would perform, as its many pores and channels should also serve for reaction sites.
When tested the foam was much more efficient at converting CO2 into formic acid, which is used to feed microbes, than planar copper. The researchers also found that small amounts of propylene were also created, which has never been reported before with copper. It appears this was the result of characteristics of the foam structure, which could mean copper foam could be tuned to deliver certain hydrocarbons in greater amounts.
Source: Brown University
Posted: August 13, 2014 10:12AM
Some of you may have noticed that looking at water with polarized sunglasses can cause the water to change appearance, depending on the angle you look at it. The reason for this is that at a certain angle, the Brewster angle, the light reflecting off of the surface is polarized. Researchers at MIT have recently developed a way to manipulate the Brewster angle to create a material that will reflect light at every angle, but one.
Normally when light comes to the boundary of two materials with different refractive indices, it will be mostly reflected, but at the Brewster angle, only some of the light is reflected, with the rest passing through. What the MIT researchers have done is created a photonic crystal that has a very narrow band of angles that will allow light to pass through it. Basically it is a mirror at all but a single angle, its Brewster angle, when it becomes transparent. To create this crystal, the researchers actually stacked one hundred photonic crystals with alternating refractive indices.
There are a number of potential uses for this angular selectivity, including privacy filters, light detectors, telescopes, and even solar power. As sunlight strikes a solar panel, it will heat up and radiate out some of the energy, but with an angular selective layer on top, the sunlight could be let through while the radiated energy is reflected back to the absorber.
Posted: August 13, 2014 05:53AM
Metal oxides are very common materials on Earth, as is water, yet the interactions between them are not well understood. We do know enough to use metal oxides as catalysts for reactions involving water, but exactly what happens is not completely known. Researchers at the University of Wisconsin, Madison however have recently made a discovery that should shed some light on the mechanisms though.
It is somewhat easy to understand how water interacts with metals, as metals can be very homogenous. Once oxygen is added though, defects can be present in the oxide layer and affect the chemical processes by allowing hydroxyls to form. Using scanning tunneling microscopy and some quantum mechanics, the researchers were able to identify the chemical structures and atoms at the defect sites. The results indicate that when the metal oxide surface is smooth and free of defects, amorphous networks of water molecules form, but when there are defects and hydroxyls, the water molecules take on a more ordered structure.
The next step is to learn how these water structures interact with other materials, and that could lead to better metal-oxide catalysts. It could also lead to advances in geochemistry and atmospheric chemistry, wherever similar processes occur.
Source: University of Wisconsin, Madison
Posted: August 12, 2014 02:08PM
Many consider graphene to be a wonder material, with its amazing electrical, optical, and mechanical characteristics. For that reason it is being investigated for many uses, including in supercapacitors. As reported by the American Chemical Society, graphene may soon have a serious competitor for supercapacitor electrodes from hemp.
Before we get too far, it is worth stating that it is not hemp, but a cousin of the plant that can be turned into a drug. The researchers decided to investigate hemp bast fibers, from the inner bark of the plant, to see if they could be processed into a form of carbon similar to graphene. Graphene already makes an ideal electrode for supercapacitors, but is expensive to make. A hemp-based alternative would be less expensive, especially bast as it is typically discarded by the industries that use hemp to manufacture products. What the researchers found is that if the fibers were heated to over 350 ºF and then heat with more intense heat, what material was left would exfoliate useable carbon nanosheets.
When the researchers tested the electrodes with an ionic liquid electrolyte, they found that they can match and even surpass graphene electrodes. It already supplied two to three times the energy density of modern supercapacitors at 12 Watt-hours per kilogram, and has an operating temperature range from freezing to 200 ºF.
Source: American Chemical Society
Posted: August 12, 2014 10:05AM
Even though everybody has a brain (though we may not all use them) it is one of the least understood organs to the human body. We simply do not know how it responds to many stimuli and finding out is not easy to do in a living person. Researchers at Tufts University have recently created a 3D model of brain tissue that could possibly be used for the very research it is hard or impossible to do safely.
The model is a modular design comprised of a scaffold of cast silk protein, a collagen gel matrix, and cortical neurons from rats. The silk began as disks that had a hole punched in them to form a doughnut, and then neurons were seeded into each doughnut before being stacked to resemble the layers of the neocortex. The assembly was then immersed in the collagen gel, which allowed axons to connect the neurons between the layers. The resulting model had the structural support for the network connectivity needed for brain activity and was viable for an impressive nine weeks.
One of the tests the researchers put the model through was dropping a weight on it. The model reacted to the trauma similar to how actual brain cells do, by releasing a neurotransmitter associated with brain damage and even electrical hyperactivity, like what is observed in brain cells after trauma.
Source: Tufts University
Posted: August 12, 2014 06:04AM
Power bricks are part of the reality of many electronics, from game consoles to mobile devices, and they can come in many shapes and sizes. All serve a similar function though of converting power in one form to another, such as from AC to DC. This conversion process is not always simple and can actually cost energy, which is why researchers at MIT have been developing systems to improve the efficiency of power electronics.
One of the ways the researchers are working to improve performance is to increase the switching frequency of the devices. A higher frequency means less power needs to be buffered in capacitors, reducing their size and heat, and enables easier redirection of the energy, because it is working with less energy. The researchers built a prototype LED driver that uses higher frequencies and ceramic capacitors, instead of the more common electrolytic capacitors, and found it could also push a power density five to ten times more than current systems.
The researchers are also looking at ways to improve power systems at server farms. Currently the power coming in has to go through many stages before reaching the servers. By reducing the steps, such as making it all DC without converting to AC at any point, the efficiency could be increased, and potentially the system's ability to adapt to use.
Posted: August 11, 2014 02:19PM
I would never hazard to guess just how many scientific discoveries were the result of serendipity, but I do know the number is continuously growing. Researchers at Carnegie Mellon University have discovered a way to create protein/polymer nanostructures that will self-assemble by pure curiosity.
Green fluorescent protein (GFP) molecules are fairly well-known and understood, and are used in many experiments. Typically GFP molecules will not bind with each other, but when the researchers added PEO-dialkyne linkers to them, the molecules assembled into long fibers. Even in this assembled state, the molecules were still fluorescent, which is important as it shows their structures were not compromised. When the researchers exposed the fibers to sound waves, they found that the structures disassembled back into the GFP molecules, but after a few days, self-assembled again.
Scientists have been looking for a material capable of reversible fibrous self-assembly for some time, as it would have uses in tissue engineering, drug delivery, nanoreactors, and imaging. As the researchers have already successfully modelled the process, this discovery could be used for precision manipulation of nanoscale objects.
Source: Carnegie Mellon University
Posted: August 11, 2014 10:20AM
It may not be easy to recognize always, but hair has many uses in Nature when it can be controlled. One example is small hairs called cilia in our nasal passages that remove particles as they sway. Researchers at MIT have recently replicated this behavior with a microhair array that could see some interesting and important applications in the future.
The material is made of a transparent sheet of silicone with very small nickel pillars on it. Being nickel, these pillars respond to magnetic fields by aligning with them. Similar work has been done before using polymers with magnetic particles, but using just nickel gets around issues with distribution. By controlling the tilt of the pillars, the researchers found they were able to influence the flow of fluids on them. This effect was strong enough that the researchers succeeded in getting water to go against gravity, when the material was against a wall. The researchers also discovered that the microhairs affected the light passing through the material, akin to how blinds deflect light coming through a window.
With the ability to control fluids and light levels, the researchers see this material having potential use with smart windows and car windshields. It may also find applications with labs-on-a-chip, as a means to control the flow of fluids in realtime.
Posted: August 11, 2014 06:24AM
The shortest path between two points may be a straight line, but it is not always the easiest. For some systems, including electronics, the easiest path can be around the edges of a material, where impurities will have a reduced impact. Researchers at the Joint Quantum Institute have succeeded in making light take such a topological path, and the approach could one day make it onto photonic chips.
Topological insulators are materials that have the special property of only conducting electrons over their surface and not through their bulk. This results in the electrons travelling with very little resistance because they can flow around impurities. By recreating this effect with photons, light signals can be made to travel with very little lose. What the JQI researchers have accomplished is a photonic array on a chip that does more than just that. Provided the light follows the outside path of the array, it loses very little energy, compared to passing through its interior, but it also will cross the array in a set amount of time. The latter is an important feature as delaying optical signals normally takes optical fiber loops kilometers in length, but this is achieved on a chip.
All of this has also been achieved with great consistency, thanks to the reduced influence of irregularities. That is especially necessary for creating integrated photonic devices as irregularities could lead to device-to-device variations, which would cut into performance.
Posted: August 8, 2014 02:04PM
Graphene has been labeled a wonder material for its amazing electrical and mechanical properties, which is why many are working to ensure its presence in future technologies. While those researchers are intentionally looking for applications, others can find them by accident. Monash University researchers have recently discovered that graphene oxide sheets can be made to change shape, which is a property that could have medical uses.
While running routine tests, the researchers discovered that the graphene oxide sheets they were working with would spontaneously take on a spherical shape. Normally such a change requires atomizers and mechanical equipment, but all the researchers were using was an external magnetic field on the sheets, which were under special pH conditions.
This is a tremendous discovery as it opens up the possibility of using graphene-based structures for drug delivery systems. By just applying a magnetic field to a patient, the graphene would change shape and deliver medicines wherever needed. The researchers are now investigating how graphene behaves in the presence of toxin, which could make it useful for disease detection.
Posted: August 8, 2014 07:47AM
Many across the world are looking forward to quantum computers, which will have the ability to run problems too complex for traditional, electronic computers. Actually building a quantum computer is a very difficult task though, and so many designs have been proposed that rely on different systems. Researchers at the Vienna University of Technology, National Institute of Informatics, and NTT Basic Research Labs have recently developed a new design that is based on diamonds and has some very valuable advantages over other designs.
At the center of quantum computers are qubits, which are analogous to electronic bits but instead of being zero or one, qubits can be both zero and one thanks to superposition. Qubits can take many forms though, including ions inside of traps, superconductors, and defects in diamond. More specifically, the diamond defects are nitrogen atoms, and these defects are kept in between two mirrors, forming an optical resonator. An optical fiber is then used to deliver a photon coupled to the system, to read and write quantum information to the nitrogen atom. The researchers have come to the conclusion that this system and the architecture they have designed is best suited for quantum computers because it lends itself well to miniaturization, mass production, and integration onto chips.
One of the algorithms that may one day be run by quantum computers is Shor-2048, which is for finding the prime factorization of 2048 bit numbers. To run it though would require a quantum computer, with error correction, to have 4.5 billion quantum systems in it. The ability to miniaturize qubits would be invaluable for one day running that algorithm, which is exactly where the diamond-based architecture may succeed.
Source: Vienna University of Technology
Posted: August 8, 2014 05:23AM
When you were young, did you have an idea of what your adult life would be like? Is that what you actually achieved? For one stellar object, it changed quite a bit between its youth and adult lives, as researchers at the Carnegie Institution have discovered something that looks like a planet, but may have been like a star at first.
WISE J0304-2705 is an object classed as a Y dwarf, which is the coolest stellar temperature class, with a temperature between 100 ºC and 150 ºC. As that puts the object between Earth and Venus, that may not seem very odd, but after analyzing its spectrum, the researchers discovered that its age makes it one of the oldest objects in the galaxy. This would suggest then that when it was younger, in its first 20 million years of life, it likely was around 2800 ºC, which is as warm as red dwarf stars. At 100 million years old, it should have been around 1500 ºC, which is cool enough for silicate clouds to form, and at one billion years old, methane and water vapor would have dominated this 1000 ºC object. Now it is barely warm enough to even boil water.
Source: Carnegie Institution
Posted: August 7, 2014 03:19PM
To see some of the constructions you can make with origami, it is almost unbelievable that they started off as simple sheets of paper. This ability to assemble complex structures from simple materials has been of interest to many, in part because of the re-configurability of the structures. Now researchers at MIT have succeeded in creating a prototype origami robot that will actually assemble itself upon batteries being attached.
The robot is comprised mostly of parts produced with a laser cuter, similar to the bakable robots MIT demonstrated a couple months ago. Instead of using the heat of a hot plate though, this robot's joints fold when heated by electrical leads. This is an important distinction as the built-in microprocessor can order the folding in a sequence, instead of having joint fold together, providing greater control over the structure. Once assembled though, the motor or motors (different designs have been tested) were able to power the legs and get the robot moving.
It is interesting to envision the possibilities for this technology as the robots are effectively printable, making them very inexpensive. What is more, we know that hollow-shell structures can be very strong, as they give insects their ability to carry objects many times their own weight.
Posted: August 7, 2014 10:02AM
Light emitting diodes have been growing in popularity in recent years, thanks to their relatively high efficiency. Compared to more traditional light sources though, they can be quite expensive though, so many are searching for ways to bring down costs. Researchers at the University of Cambridge, University of Oxford, and Ludwig-Maximilians-Universität have recently discovered a form of perovskite that is inexpensive, but is still a very clean semiconductor.
Perovskite is a class of materials with a special structure made of cuboid and diamond shapes, which also have superconducting and ferroelectric properties. In this research, it was organometal halide perovskites, consisting of lead, carbon-based ions, and halides, that were used. These materials easily dissolve in common solvents and form crystals when dried, which makes them very cheap and easy to produce, especially compared to the materials traditional used to make LEDs. The key discovery to this research though was that the crystals that formed had very clean semiconductor properties, and would not need to be run through purification processes to be useable for LEDs.
Another aspect of perovskite that makes LEDs based on them interesting is that they can be easily tuned to emit different colors, potentially enabling them to be used in future displays. The researchers estimate it may be five years before we may see perovskite-based LEDs being commercially available though.
Source: University of Cambridge