Welcome Stranger to OCC!Login | Register

Science & Technology News (808)

Improving Radio-Chip Efficiencies

Category: Science & Technology
Posted: March 2, 2015 06:53AM
Author: Guest_Jim_*

Efficiency is important for just about all electronics, and that is not going to change any time soon. In fact if we do see the Internet of Things become a reality, efficiency is going to be key to connecting all of our various devices and appliances. To that end, researchers at MIT have developed a way to significantly improve the efficiency of radio chips by reducing off-state leakage.

Semiconductors are interesting electronic materials as they possess both conductive and insulating properties, which can be switched on and off. Because they are not perfect insulators, the transistors made of them can leak some energy when they are in their off-state. To improve the insulating properties, the researchers push a negative charge into a wire running across the transistor, as this stops the electrons that would otherwise leak out. A charge pump is used to create the negative charge.

As you may have guessed, this negative charge does take some power to produce, but at the cost of 20 picowatts, some 10,000 pW can be saved. If devices are going to start having sensors and transmitters built in to build an Internet of things, such efficiency will practically be a necessity.

Source: MIT

Trapping Vortices to Improve Superconductors

Category: Science & Technology
Posted: February 27, 2015 09:58AM
Author: Guest_Jim_*

The prospect of materials being able to carry electrical currents without resistance has been of great interest to people for a long time now, but achieving it has proven very difficult. Superconductivity is a somewhat fragile state, as many things can disrupt it, so we need to find ways to either remove these disruptions, or control them. Researchers at John Hopkins University have done the latter by trapping electron vortices.

Electron vortices occur in superconductors when they are exposed to magnetic fields, and they can disrupt the resistance-free supercurrents as they move around. Along the edge of the superconductor, the vortices will be pinned in place, but in the bulk of a material it is much harder to stop them from moving. The researchers' solution to the problem was to make an aluminum nanowire, as it is mostly edges. This caused the vortices to become trapped on the edge and form a single row, which the supercurrent was able to avoid.

Besides demonstrating a way to stop these vortices from interfering, this research could also prove useful in other ways. Some day we could see the vortices used to transmit information, like how electrical charges are used today.

Source: John Hopkins University

Another Use for Graphene: Treating Cancer

Category: Science & Technology
Posted: February 27, 2015 06:14AM
Author: Guest_Jim_*

I am starting to wonder if graphene is more amazing or ridiculous as its number of applications continues to increase. Researchers at the University of Manchester have discovered that graphene oxide could be used to treat cancer. More specifically it can target cancer stem cells and prevent them from forming tumor-spheres.

Cancer stem cells (CSCs) are exactly what they sound like; cancer cells that can differentiate into other cancers and are what causes cancer to spread. They also have to do with cancer recurring after treatment. Graphene oxide has been investigated for use in biomedicine before, because it is able to enter or attach to cell surfaces, but this is the first time it has been shown to work as an anti-cancer drug on its own. It appears it attaches to the surfaces of the CSCs and blocks the pathways used to form tumor-spheres. The researchers also observed it triggering the differentiation of the CSCs into non-cancer stem cells. The tests were done with six different cancer types (breast, pancreatic, lung, brain, ovarian, and prostate) and it was effective against all of them, suggesting it could work with a larger number of cancers, and perhaps even all of them.

Normally CSCs are unaffected by radiation and chemotherapies, which kill bulk cancer cells, so a means to target them directly is very important. Of course a lot of work will have to be done before graphene oxide flakes could be used for treating cancer, but this is still a very significant discovery.

Source: University of Manchester

Potentially New Class of Superconductors Found

Category: Science & Technology
Posted: February 26, 2015 02:04PM
Author: Guest_Jim_*

Many people want to see a future filled with superconductors, because these materials are capable of transmitting electricity without resistance. One of the reasons why we are not currently using them much is that they require being cooled to very low temperatures; some near absolute zero. Researchers at the University of Southern California however have recently discovered a potentially new class of superconductors based on superatoms.

Superatoms are homogenous clusters of normal atoms, so even though they consist of many atoms, they will act as one, though a rather large one. This made the researchers wonder if some phenomena, such as Cooper pairs, could by exhibited by the superatoms. Cooper pairs are pairs of electrons that form in superconductors and help achieve that superconductivity. To test this hypothesis the research built superatoms containing 37, 44, 66, and 68 atoms of aluminum and then shot lasers of increasing energy at them. Normally laser pulses of higher energy will cause more electrons to be ejected, but at certain energy levels the electrons resisted.

One explanation for this resistance is that the electrons had formed Cooper pairs, which is supported by fewer electrons being knocked at as the temperature dropped, with the critical point around 100 K. While that is still a pretty cold temperature, it is only the beginning so with more work, the researchers think they may be able to create superatoms with higher superconducting critical points.

Source: University of Southern California

Simulating Materials to Hopefully Understand Superconductivity

Category: Science & Technology
Posted: February 26, 2015 06:38AM
Author: Guest_Jim_*

For decades we have known about high temperature superconductors, but despite our time with them, we know little about how they work. With such understanding it may be possible to design new superconductors that work at room temperature. There is a model that may provide the explanation, and finally researchers at Rice University with an international team have taken an important step in testing the model.

The Hubbard model was developed in the 1960s to describe the magnetic and conduction properties of electrons in transition metals and their oxides. It is actually a simple model, but it becomes exponentially more difficult to process as more electrons are involved, which is why even supercomputers have been unable to test it. The solution the Rice researchers developed is to physically model the materials in question. Instead of working with electrons moving between sites in a lattice, the researchers placed ultracold atoms in an optical lattice and watched the movement of ions in the lattice. They observed antiferromagnetic order, just as the Hubbard model predicts, and by using the Quantum Monte Carlo method, the results of the experiment were confirmed to match the Hubbard model.

Even though it was not superconductivity that was observed, this is an important step towards that goal as most parent materials of high temperature superconductors are antiferromagnetic. By developing new measurement methods and finding ways to chill the atoms even more, the researchers hope to be able to model the electron pair correlations that result in superconductivity.

Source: Rice University

New Electrolyte for Better Batteries

Category: Science & Technology
Posted: February 25, 2015 02:25PM
Author: Guest_Jim_*

The world would be a very different place if not for batteries; especially modern lithium-ion batteries. These batteries seem to be approaching their limits though, unless new technologies and materials are developed. One thing holding back some new designs has been the formation of dendrites, but researchers at the Pacific Northwest National Laboratory have found a solution to that.

Dendrites are small structures that can form in batteries and lead to reduce capacities, short circuits, and even fires. If a material for a battery's anode reacts with the electrolyte to produce dendrites, it does not matter how much better that anode would be, because the battery will fail sooner. What the PNNL researchers have been investigating is new electrolytes that prevent dendrites from forming. In this area some others of have had success with electrolyte with high salt concentrations, so that is where the researchers started. They built a circular test cell with their new electrolyte and a lithium anode. Lithium anodes can hold ten times the energy of conventional graphite anodes, but easily form dendrites. In the test cell though, instead of dendrites forming, a thin layer of lithium nodules formed, which did not short-circuit the battery.

After 1000 cycles, the test cell still held 98.4% of its original energy at 4 milliAmps per square centimeter. With such high efficiency the researchers suspect it may be possible to do away with the anode in batteries using this electrolyte, and use a current collector, but more work needs to be done to determine that.

Source: Pacific Northwest National Laboratory

Bringing Spintronics Closer to Reality With a New Semiconductor

Category: Science & Technology
Posted: February 25, 2015 05:02AM
Author: Guest_Jim_*

The traditional electronics we use every day are approaching their limits, so researchers have been working on a variety of replacements, including spintronics. Instead of relying on the charge of electrons, spintronics uses the spin of the fundamental particles, which can off several performance benefits. One of the challenges still to overcome though is finding a suitable material to make spintronics out of, but researchers at the University of Michigan have created one that could do the trick.

The ideal semiconductor for spintronics could have a number of its properties precisely tuned, including magnetism and conductivity. These characteristics can be tuned already by adding atoms to the crystal lattice, but typically this happens evenly across the whole semiconductor, and spintronics would want them to vary. To hopefully solve this problem, the researchers have developed a new material without a symmetrical crystal structure. That means the holes for accepting the doping atoms vary in size across the material, allowing for new arrangements and combinations.

The semiconductor is made of iron, bismuth, and selenium and while it has great potential, it will be a bit longer before it can be tested. So far the researchers have only made it in powder form, but next they plan on making it into the thin films that would actually be used in a spintronic device.

Source: University of Michigan

New Ultra-Thin Lens Developed

Category: Science & Technology
Posted: February 24, 2015 02:03PM
Author: Guest_Jim_*

It is hard to say how many lenses you may have encountered in your life, but I know some I have come across have been quite large and thick. That may change in the future though, as many are looking to nanotechnology and metamaterials to create flat lenses. Now researchers at Harvard University have developed the first flat lens that can work with multiple frequencies of light at the same time.

Flat lenses have been built before, but they normally only focus one color of light, while others are diffracted at different angles. The Harvard researchers' new device however uses silicon antennas on a glass substrate to bend multiple colors of light at the same angle. Other designs would bend different frequencies at different angles, but this one compensates for that. So far the researchers have built two prototype achromatic metasurfaces, as they are calling the lenses, which are able to work with three different colors. One of the lenses deflects the three colors at the same angle, while the second instead focuses all three to the same point. Simulations suggest the design could be adapted to work with many more wavelengths than just three.

Flat lenses like these could be used in a variety of optical devices, including microscopes, telescopes, and even computers. Anywhere that the bulk of traditional lenses can pose a problem, this research could be applied.

Source: Harvard University

Repairing Nerves with 3D Printed Guides

Category: Science & Technology
Posted: February 24, 2015 06:44AM
Author: Guest_Jim_*

There are many applications for 3D printing, and not least among them are medical uses such as specialized scaffolds that direct and promote cell growth. Researchers at the University of Sheffield have recently printed a nerve guidance conduit (NGC) which is able to guide nerve ends to repair naturally. This could have an enormous impact on future treatments for various traumatic injuries.

Normally repairing nerve damage involves surgery that sutures or grafts endings together, which tends to produce imperfect results. The use of an NGC however can improve results, as its framework of tubes guide nerve ends to toward each other for natural repairs. Some are already used in surgery, but they are limited in design and materials, which naturally restricts the injuries they can be used to treat. By using Computer Aided Design (CAD) and a form of 3D printing (laser direct writing) the Sheffield researchers are able to craft NGCs for any kind of nerve damage, and even tailor designs for specific patients.

The researchers have tested their NGCs using a novel mouse model and shown that they were able demonstrate a repair over an injury gap of 3 mm in just three weeks. With more work the printed NGCs could be made to repair larger injuries, and be made from biodegradable materials.

Source: University of Sheffield

Developing Tools to Advance Wireless Communication

Category: Science & Technology
Posted: February 23, 2015 02:08PM
Author: Guest_Jim_*

In one way or another, chances are that we all rely on wireless communications like cellular connections or Wi-Fi. These various technologies have been serving us well for years now, but like all technologies, we want them to improve and that is going to require pushing limits and entering new territories. In this case, those new territories are higher frequencies and to help us get there, NIST is developing tools to measure signals at these higher frequencies.

Most wireless communications today operate below 3 GHz, but thanks to silicon-germanium radio chips we are reaching into the millimeter wavelengths, which are above 10 GHz. The NIST researchers are aiming for 100 GHz, and greater. One of the issues with frequencies this high is that the high speed circuits needed to generate them can also distort them. Even small errors can pose a problem. Also mm waves have a harder time going around corners than lower frequencies, which will make modeling the wireless channels more difficult. One way to solve that problem is to use complex arrays of antennas that allow beams to be steered directly to devices.

So far the researchers have built test receivers and channel sounders and demonstrated a calibrated signal source capable of generating 44 GHz and 94 GHz signals. The source uses commercial parts, so companies should be able to build their own systems for testing.

Source: NIST

Bringing Electronics Into Fibers

Category: Science & Technology
Posted: February 23, 2015 05:52AM
Author: Guest_Jim_*

Always in science, a failure is something to learn from, and sometimes a failure is just an unexpected success. Such was the case for some MIT researchers who accidentally discovered a way to produce a pure silicon core in a fiber. This discovery could potentially lead to many new technologies, if more complex electronics structures can be built inside the fibers.

Originally the researchers were trying to find ways to incorporate metal wires inside of fibers, so they were working with common silica and silver, copper, and aluminum. They would start by arranging the materials inside what is called a preform, which is a larger block or cylinder, and then heat and draw it out, resulting in a thin fiber with the same composition as the preform. At least that is what they expected, but when the fiber with aluminum was pulled out, instead of a shiny metallic core, the core was a darker material. Initially the sample was going to be discarded as a failure, but the researchers instead decided to examine it more closely and found that the black core was actually pure silicon. What happened was actually a well-known chemical reaction, which converted the silica and aluminum into pure silicon and aluminum oxide.

With a pure silicon core, these fibers could be used to build advanced electronics, like transistors or solar cells, if other materials could be integrated as well. The best part though might be that the process starts with inexpensive silica and gives you pure silicon in the end, instead of requiring the more expensive material at the beginning.

Source: MIT

Predicting the Past in Quantum Mechanics

Category: Science & Technology
Posted: February 20, 2015 02:49PM
Author: Guest_Jim_*

If you are not convinced that quantum mechanics is weird, keep reading and check out the source too. For the physics we live with every day, time runs in one direction, and the past influences the future, but not the other way around. As researchers at Washington University in St. Louis have discovered though, in the quantum world the future and the past can influence the state of a system, instead of just the past.

In our normal world, if you follow a system up to some event, you can predict what happens with the information you collected. In quantum mechanics though, the odds of guessing right are about 50-50, even if you know everything about a quantum particle leading up to the event. To confirm this, the researchers put a superconducting circuit into a superposition, creating a qubit, and placed it in a microwave box. When some microwave photons are put in the box, they will interact with the qubit and gain some information about it, without collapsing the superposition. The researchers then took a strong measurement of the qubit, which would cause it to collapse, but they hid the result and continued using the photons to make weak measurements.

When the researchers predicted what the strong measurement would be using just the information leading up to it, they were correct half of the time. However, when they ran the equations backwards with the weak measurements following the hard measurement, creating hindsight predictions or "retrodictions," they were right 90% of the time. This indicates that the state of the qubit incorporates information not only from what led up to the strong measurement, but also from what followed it. This results returns time symmetry to quantum mechanics and could have some interesting applications, such as making more robust chemical reactions and improving quantum computing.

Source: Washington University in St. Louis

Star May Have Come Within a Light Year of Earth

Category: Science & Technology
Posted: February 20, 2015 06:25AM
Author: Guest_Jim_*

When you look up into the night sky, you can think about how remote much of the Universe is, but some of it was once closer than you may think. Researchers at the University of Rochester and institutions across the world, have recently determined that a star likely passed within a light year of the Sun about 70,000 year ago.

Called Scholz's star for its discoverer, the star is a dim red dwarf, about 8% the Sun's mass, and is part of a binary system that includes a brown dwarf, that weighs in at 6% of the Sun's mass. Currently it is about 20 light years away but it has some unusual characteristics. The main thing is that it has little tangential motion, which means it is moving almost directly away from the Solar System, unlike most stars at that distance. This indicates it either passed by us in the past, or will in the future. Radial velocity measurements showed that it is moving away, so it must have gone by us before. To determine when it did and what its influence may have been, the researchers modelled its orbit 10,000 times, and of those 98% showed it passed through the outer Oort cloud, at a distance of just 0.8 light years away.

While it may have passed through the outer Oort cloud, which is at the edge of the Solar System and holds trillions comets, it likely did not perturb it much. It may have been visible to humans 70,000 years ago, because even though it is too dim to see with the naked eye, it could have flared and become visible for minutes or hours at a time.

Source: University of Rochester

Better Data Placement in Multicore Chips

Category: Science & Technology
Posted: February 19, 2015 02:08PM
Author: Guest_Jim_*

When we have work to do, we like keeping what we need nearby, to speed up the process. The processing cores in our computers also like keeping their work nearby, but finding the best placement is anything but easy. However, researchers at MIT have developed a new optimization algorithm that is significantly faster than others, and could significantly speed up processors.

The problem has to do with the placement of data and keeping the related computations nearby. This is similar to the 'place and route' problem of minimizing the distance between logic circuits, which is NP-hard, meaning it is computationally impossible to find the optimal solution to. However, algorithms that approximate the optimal solution can be run over the course of several hours. The new MIT algorithm however completes in just 25 milliseconds and is better than 99% efficient, compared to those other algorithms. It works by roughly placing the data across the memory banks, to keep it all spread out and not clumped into the same area. It then places the computational threads near the data, and refines the placement of the data, based on the placement of the threads. While this process could be repeated, it only provides a 1% increase, which is not exactly worth it. When the researchers applied the algorithm to a simulated 64-core chip, it improved computational speeds by 64% and reduced power consumption by 36%.

If built into real chips, the dedicated circuitry would take up about 1% of the chip's area. The researchers believe chipmakers will consider this a fair loss, considering the performance improvements this algorithm could provide by constantly monitoring a processor.

Source: MIT

Silicon Nanofibers for Better Batteries

Category: Science & Technology
Posted: February 19, 2015 06:45AM
Author: Guest_Jim_*

Battery technology is quickly approaching a limit that can only be avoided with new materials, as graphite electrodes can only hold so many ions. Other materials are being investigated, but they present their own challenges, like silicon's significant expansion as it absorbs ions. Researchers at the University of California, Riverside have found a way around that problem though, and another, with nanofibers.

In theory, lithium-ion batteries that use silicon electrodes could store ten times more energy, because silicon can hold that many much more charge for its weight. The problem is that as the silicon absorbs ions, it expands so much that it can fracture and degrade performance or destroy the battery. The Riverside researchers however are working with silicon nanofibers in a sponge-like structure that can get around that expansion issue. They make the fibers using electrospinning, which applies 20,000 to 40,000 volts to a rotating drum and nozzle as it emits a solution of tetraethyl orthosilicate. This materials used in the semiconductor industry, and by exposing it to a magnesium vapor, the sponge-like structure is produced.

While the ability of the silicon to survive hundreds of charge/discharge cycles is significant on its own, the production method offers another benefit. In the lab the researchers were able to create several grams of the material, while other potential graphite replacements, like carbon nanotubes and silicon nanowires, are only produced micrograms at a time.

Source: University of California, Riverside

Life May Be Older Than We Thought

Category: Science & Technology
Posted: February 18, 2015 02:14PM
Author: Guest_Jim_*

Currently, Earth supports the only known life in the Universe, but it took a long time before the planet could support much life. One of the steps required for this transformation was for nitrogen to be pulled out of the atmosphere so it could build various molecules necessary for life. Analysis of these nitrogen-fixing enzymes puts their age between 1.5 and 2.2 billion years, but researchers at the University of Washington have found evidence to push that back another billion years.

For their study, the researchers used fifty-two rock samples between 2.75 and 3.2 billion years old, and they represent some of the oldest and best-preserved rocks on the planet. Part of the reason these rocks are so well preserved is because they formed before the atmosphere gained oxygen, which can destroy chemical clues. All of these rocks, even the oldest ones, indicated nitrogen was being pulled out of the air by the ratio of heavier and lighter nitrogen isotopes. This ratio could only be achieved in the presence of nitrogen-fixing enzymes in single-celled organisms.

Further analysis of the rock samples indicate the enzyme was based on molybdenum, which is common today, but indicates something else about that prehistoric life. Today molybdenum-based enzymes are common because of oxygen reacting with rocks and it washing into the ocean, but little oxygen would have been present 3.2 billion years ago. To explain this, the researchers suggest that some life may have existed on land, releasing enough oxygen to provide the necessary molybdenum.

Source: University of Washington

New Material Stretches Itself When Cooled

Category: Science & Technology
Posted: February 18, 2015 06:33AM
Author: Guest_Jim_*

Most materials will expand, if only slightly, when heated but there are some polymers that will actually expand when cooled. These shape-memory polymers have some drawbacks though, but researchers at the University of Rochester have developed a new material without those issues.

Normally shape-memory polymers need to be programmed each time they are heated and cooled, as to what shape they are supposed to take on. This programming requires attaching small loads to it to direct the process. The Rochester researchers got around this by introducing permanent stress inside of the material. When the material was heated, they attached a load to cause it to take a shape. They then added crosslinks to the otherwise loose network of molecules, so when the material cooled and crystallized, it did so in a preferred direction. By building the stress into the molecular structure, the loads are no longer necessary for the material to remember what shape to take when cooled. Even after multiple heating and cooling cycles, the material returned to its original and programmed shape without noticeable deviation.

Besides being cool, a shape-memory polymer like this could find many useful applications with biotechnology, artificial muscles, and robotics. Next the researchers are working on optimizing the system by adjusting how the crosslinks tie together.

Source: University of Rochester

Working with New 2D Materials

Category: Science & Technology
Posted: February 17, 2015 02:46PM
Author: Guest_Jim_*

Two dimensional materials have been of great interest for years now, as they can possess some very unusual and useful properties. Graphene is a prime example of this, with it tremendous strength, conductivity, and flexibility, and so is germanane, an atom-thick sheet of germanium. Germanane was first made a couple years ago at Ohio State University, and since then the researchers have been tinkering with it and making some interesting discoveries.

There is a little irony to the work with germanane for potential use in future computers, as germanium was used to make transistors before silicon, the current standard. The researchers are trying to keep the work within what is possible with silicon fabrication methods though. Part of their work has been focused on manipulating germanane's optical properties. It already transmits electron some 10 times faster than silicon and is better at absorbing light, but by tuning germanane's electron structure, it may be able to interact with a significantly wider portion of the spectrum than currently possible. This could lead to improved LEDs, lasers, solar cells, and more.

The researchers have also been investigating a 2D tin material by making germanane samples that contain 9% tin atoms. It has been theoretically predicted that a 2D tin material would be a topological insulator and capable of transmitting electrons with 100% efficiency, at room temperature. The predictions also state that only certain bonds would form on the material's top and bottom, which the researchers observed with the germanane samples.

Source: Ohio State University

Telescopic Contacts and Wink-to-Zoom Glasses

Category: Science & Technology
Posted: February 17, 2015 07:09AM
Author: Guest_Jim_*

Vision is a very important sense and many people would say they cannot live without it, so naturally many technologies have been developed to correct imperfect vision. Age-related macular degeneration is the leading cause of blindness in older adults, so it has gotten some special attention. Researchers from Ecole Polytechnique Fédérale de Lausanne recently demonstrated telescopic contact lenses and smart glasses for fighting the condition.

The contact lenses utilize a thin reflective telescope made of plastics, aluminum mirrors, polarizing thin films, and biologically safe glues to hold it all together. When light enters the lenses, it is bounced around by the mirrors, to expand the image resulting in a 2.8 times magnification. To keep the lenses safe to use, the researchers have incorporated 0.1 mm wide air channels in them, to allow oxygen to reach the eye.

The glasses work with the contact lenses to select whether you see a normal or magnified image. When you wish to see normal vision, the glasses allow through light of with the polarization matching the lenses' 1x aperture, while a different polarization matches the 2.8x aperture. The glasses have a light source and detector in order to distinguish winks from blinks, because it is winking one eye or the other that switches between the magnifications.

Source: Ecole Polytechnique Fédérale de Lausanne via EurekAlert!

Long Term Data Storage with DNA

Category: Science & Technology
Posted: February 16, 2015 07:03AM
Author: Guest_Jim_*

Every day, information about our past is lost as people die, films fade, and objects erode away. While there are many preservations initiatives to prevent the loss of our history, a means to store this information for the long term is still needed. One possibility is to write the information into DNA, and now researchers at ETH Zurich have found a way to overcome that particular medium's issues.

One of the issues of DNA data storage is that the DNA must be protected from the environment. Samples that are hundreds of thousands of years old are retrieved from bones, so to replicate this protection, the researchers used silica microspheres some 150 nm wide. The researchers tested it against the DNA being stored in a biopolymer and on impregnated filter paper, and it showed itself to be particularly robust. It is also rather easy to retrieve the DNA using a fluoride solution.

Another issue is that errors can occur in the data, which is naturally undesirable for long-term data storage. To address this, the researchers applied a scheme similar to those used for long-range data transmission and found it enabled the data to be retrieved, error-free.

Source: ETH Zurich

Predicting Nonlinear Optical Properties for Metamaterials

Category: Science & Technology
Posted: February 13, 2015 02:45PM
Author: Guest_Jim_*

Metamaterials are a curious class of materials that have the unique quality of possessing properties not found in Nature. Some of these materials' properties have been engineered by the people making them, but not all of them. The nonlinear optical properties are one example where the physics still need to be understood, but now researchers at Berkeley Lab have found a theory to predict these properties.

If you shine a light into a material, you expect the color of the light to remain the same, but some materials will change it. These are called nonlinear materials and they have a number of uses, for example some lasers use them to produce otherwise unobtainable higher frequencies of light. Some metamaterials are also nonlinear, but they cannot be described with the same rule used for natural materials. What the Berkeley researchers have found is that a nonlinear light scattering theory developed for nanostructures actually does work.

Metamaterials with their engineered optical properties could see use in advanced microscopes and other devices, but all of their properties will have to be understood first. By discovering this theory can be applied, that level of understanding is coming closer.

Source: Berkeley Lab

Reality, Not Perfection Preferred for Online Dating Profiles

Category: Science & Technology
Posted: February 13, 2015 06:51AM
Author: Guest_Jim_*

Fairly often we want to present ourselves in the best light by focusing on our successes and avoiding or downplaying our failings, because we think it will make us look better in the eyes of others. Researchers at the University of Iowa decided to investigate how effective that strategy is for online dating profiles and found that looking perfect is not the perfect plan.

The researchers put together eight profile, four men and four women, that lay along the spectrum between Selective Self-Presentation (SSP) and Warranting. Warranting contains information that is easily traced to a real person, such as links to what is mentioned in the profile, while SSP only shows what is good about the person. These profiles were then shown to 317 adults, of which 150 were men and 167 were women, with an average age of 40. The researchers expected the high SSP profiles, which sounded perfect, to be the most popular, but the reverse was the case.

Instead of the perfect profiles, the people preferred the more realistic profiles as they viewed it as more trustworthy. It appears this may come from the expectation of people misrepresenting themselves in these profiles, making the realistic ones more appreciated.

Source: University of Iowa

Influenza Virion Modelled on a Computer

Category: Science & Technology
Posted: February 12, 2015 02:05PM
Author: Guest_Jim_*

It is never fun to catch the flu, so it is not surprising that a number of treatments have been developed, from those deployed by doctors to old wives' tales. To help improve and discover new strategies, researchers at the University of Oxford have built the first complete model of the outer envelope of an influenza A virion.

A virion is a complete virus particle, so modeling it allows people researchers to study how it behaves in different environments, and the efficacy of drugs meant to destroy the virus. In this case the researchers made the interesting discovery that the spike proteins on the particle's membrane spread out, instead of moving closer together. These proteins impact how the virion interacts with its host cell, and this information could be used to better design antigens.

Currently the model only spans a very short period of time for a single virion, but overtime it may expand to multiple particles in various environments. This would be useful for learning how the particles behave and survive over the course of a year.

Source: Biophysical Society via EurekAlert!

Inkjet-Like System Developed for Making OLED Displays

Category: Science & Technology
Posted: February 12, 2015 07:01AM
Author: Guest_Jim_*

Chances are that if you have been following displays in recent years you have heard about OLEDs. There is great interest in them because pixels in an OLED display emit their own light, instead of needing a backlight, and the displays can be flexible. While there are many products that use them, OLED displays are still uncommon in part because they are still expensive, but that should be changing soon, thanks to researchers at MIT and their startup Kateeva.

Like many relatively young technologies, the promise of OLEDs has been talked about a lot, but not all of them have been realized. The flexibility of the thin films has been demonstrated, as has the improved brightness and saturation, thanks to the pixels directly emitting light. What has not quite materialized yet though is the lower cost of manufacturing. This is what the MIT researchers have tackled with their inkjet-like YIELDjet platform. YIELDjet FLEX is one of two technologies they have developed, and this one protects the OLED material from being exposed to contaminates by using a nitrogen chamber. Normally a vacuum chamber would be used, but the nitrogen chamber is ten times more effective and cuts down on waste and cost. The researchers hope to see displays made with YIELDjet FLEX in products by the end of the year.

The second YIELDjet technology the researchers have created removes the need of shadow masks for laying down patterns. Instead of the masks, which cause waste and can cause defects, the new system uses print heads with hundreds of nozzles to deposit the OLED materials directly onto a substrate. This could potentially cut the costs of larger displays by half.

Source: MIT

Bringing Designer Chemistry to 3D Printing

Category: Science & Technology
Posted: February 11, 2015 02:27PM
Author: Guest_Jim_*

For many people, the promise of 3D printing is an easy way to produce parts and objects cheaply, from a table-top device. For some though, the technology has more potential by merging it with other things. Researchers at the University of Washington have done just that by adding special molecules to the filament.

The 3D printer the researchers were working with possessed two print heads and while one contained just polycaprolactone, the other contained a mixture of 99.5% of that plastic and insertions of spiropyran. Spiropyran is a molecule that will change color when it is stretched. With the inclusion of this molecule, the researchers were able to print objects that reacted to stretching, acting like a force meter. It took just 15 minutes for them to print their force sensitive object, with materials that cost less than a dollar, indicating that this incorporation of designer chemistry can be done quickly and cheaply.

By merging 3D printing and designer chemistry, there is definite potential for new applications, such as passive force meters and medical implants.

Source: University of Washington

Discovery in Haptics Could Lead to Touch-Back Technologies

Category: Science & Technology
Posted: February 11, 2015 06:37AM
Author: Guest_Jim_*

From rumble packs to clicky keyboards, haptics are an important part of our experiences with technologies. Except that is with touchscreens, as though surfaces remain flat to the touch, but work is being done to change that. Researchers at Northwestern University and Carnegie Mellon University have recently made a discovery that active haptic feedback to touchscreens.

To do their experiment, the researchers worked with the virtual bump illusion, which uses forces on fingers to make a person think they are touching a bump on a surface. This is a well-known phenomenon. What the researchers discovered has to do with how the brain interprets information from multiple fingers at the same time. The subjects were asked to run two of their fingers over a flat surface with two virtual bumps on it. However, if the distance between the two bumps matched the distance between the two fingers, the brain will actually think it encountered one bump instead of two.

This discovery provides a window into how the brain registers sensory information, which is important if haptic screens are ever developed.

Source: Northwestern University

Controlling Nanowire Growth with Catalysts

Category: Science & Technology
Posted: February 10, 2015 02:24PM
Author: Guest_Jim_*

Working with nanoscale structures can be very difficult for the obvious reason that they are very small. This includes nanowires, which could eventually be used for advanced optical technologies, because their optical properties can be tuned. That tuning is very difficult to realize though, on nanostructures, but researchers at Berkeley Lab have made a discovery that could ease that problem.

The researchers were specifically working with gallium nitride nanowires, because in its bulk form the material interacts with blue and ultraviolet light but adding indium allows it to interact with red light as well. In this case the catch is that the indium atoms stress the material and degrade performance. As nanowires though, that stress is not an issue, but tunability still is. To address that issue the researchers investigated what would happen if bi-metallic catalysts were used to grow the nanowires. Normally only single metal catalysts have been used, but the gold nickel alloy used gave the researchers control over the orientation of the nanowires, depending on the amount of each metal.

It appears the reason for this control comes from how the nanowires align with the surface of the alloy substrate. The researchers also found that this affected the surface properties of the nanowires, and surface properties are very powerful for nanostructures. This is the area the researchers are focusing on next, to see how far they can go in tailoring the nanowires' optical properties.

Source: Berkeley Lab

New Allotrope of Carbon Discovered

Category: Science & Technology
Posted: February 10, 2015 07:19AM
Author: Guest_Jim_*

Carbon is an amazing element in part because it can form so many materials with various properties, including graphite, diamond, fullerenes, nanotubes, and graphene. Since its discovery, graphene has been of particular interest for its mechanical and electrical properties. Now a new allotrope of carbon modelled by researchers at Virginia Commonwealth University may steal away some of that interest.

Graphene is an atom-thick sheet of carbon atoms arranged in a hexagonal structure, like chicken wire. What the Virginia researchers have theorized is a pentagonal structure, which is why they call the new material penta-graphene. According to their predictions, the new material would be very stable, very strong, and survive temperatures up to 1000 K. It would also have the curious property that if you stretch it in one direction, it will expand in the perpendicular direction as well, instead of contracting. Perhaps most interesting is that it will be a semiconductor and not a conductor, like graphene is.

Sadly all of the work so far is theoretical and based on computer models, so a means of fabricating it must be discovered to test any of it. Once that is achieved though, you can bet a lot of people will be exploring penta-graphene's various applications.

Source: Virginia Commonwealth University

Mapping Temperatures in Transistors

Category: Science & Technology
Posted: February 9, 2015 02:43PM
Author: Guest_Jim_*

We all know how important it is to keep our electronics cool, and on the macroscale, this is not hard to achieve. On the microscale however, it is more difficult because even measuring the temperature of the components is a challenge. Researchers at the University of Southern California though have found an ingenious way to make those measurements, which should translate to the semiconductor industry easily.

Part of what makes it so hard to measure the temperature of a microelectronic device, like a transistor, is that a temperature probe will actually affect the temperature of the system. This makes accurate measurements impossible, so simulations have been used to infer temperatures within devices. The California researchers realized a way to make the measurements without a temperature probe by using an electron microscope. When the temperature of a material changes, so too does its volume and density, which is what the researchers are measuring with a transmission electron microscope. The electrons from the microscope creates plasmons in the material, which shift depending on its density, and now these shifts have been analyzed closely enough to make local temperature measurements.

Among the advantages of this new technique, named Plasmon Energy Expansion Thermometry, is that it can measure temperatures within a device, like a transistor, and not just on its surface. Semiconductor manufacturers already use transmission electron microscopes to measure the size of their devices, so measuring temperatures should not be too difficult for them to do as well. The research has so far been done with aluminum, so the next step is to translate the technique to other materials, including silicon.

Source: University of Southern California via EurekAlert!

Double the Distance of Fiber Optic Signals

Category: Science & Technology
Posted: February 9, 2015 06:02AM
Author: Guest_Jim_*

Of all the data used by humanity, some 99% of it travels along optical fibers, and with demand for the Internet rising, the capacity of optical fibers becomes more and more important. One way to carry more information on optical fibers is to send multiple signals at different frequencies. The issue is that these separate optical channels will still interfere with each other, causing errors, but researchers at University College London have found a way to address it.

What the researchers achieved was a way to receive all of the optical channels together, effectively eliminating the interactions between them. The researchers have already tested it using a 16QAM super-channel and high-speed super-receiver, successfully receiving all of the channels without error. The researchers are next want to test with 64QAM, 256QAM, and 1024QAM, which are super-channels used for digital cable TV, cable modems, and Ethernet connections respectively. To add a bit more context to this advancement, currently optical signals can travel about 3190 Km without error. This method would increase the error-free distance to 5890 Km just be changing the receiver; without having to replace the optical cables, which can be an expensive endeavor.

Source: University College London

Random Pic
© 2001-2015 Overclockers Club ® Privacy Policy

Also part of our network: TalkAndroid, Android Forum, iPhone Informer, Neoseeker, and Used Audio Classifieds

Elapsed: 0.2937140465