New plastic sorting system relies on fluorescent signatures
August 22, 2014
America has a plastic problem. According to a report issued by Columbia University, only 6.5 percent of used plastics generated in the United States is recycled, 7.7 percent are incinerated and the remaining 85.8 percent ends up in landfills. That accounts for nearly 28.9 million tons of plastic that could be recycled that ends up taking up space in landfills. Fortunately, a new technique for sorting plastic may change the game for recycling by helping to automate the process of separating recyclables from trash.
Developed by researchers at Ludwig-Maximilians-Universitaet Muenchen, the new process automatically identifies polymers, increasing the speed and accuracy of sorting methods. Led by Heinz Langhals, PhD of LMU's Department of Chemistry, the research team was able to create a method for identifying polymer-specific intrinsic fluorescence induced by photoexcitation. With a machine that is able to pinpoint the presence of plastic's telltale fluorescent signature, it can quickly locate recyclable polymers and extract them from the rest of the trash.
According to Langhals, "Plastics emit fluorescent light when exposed to a brief flash of light, and the emission decays with time in a distinctive pattern. Thus, their fluorescence lifetimes are highly characteristic for the different types of polymers, and can serve as an identifying fingerprint."
The fluorescence that occurs after exposure to a brief flash of light is read by photoelectric sensors that can measure the intensity of the light. Based on the intensity as well as the rate and pattern of the decay allows the sensors to determine which objects are plastic. In fact, this device can even detect different kinds of plastic, due to the fact that different blends of polymers show up with different fluorescent signatures.
This is incredibly important for recycling plants, because the different types of plastic can only be recycled for certain purposes. For instance, number one plastics, or polyethylene terephthalate, is used for storing edible and potable products. This plastic is safe to recycle for just about any purpose. Number three plastic, on the other hand, is highly toxic if consumed. Also known as polyvinyl chloride, or PVC, this material is used for bags, bedding, shrink wrap, plastic toys and piping, but it contains DEHP, which is a plastic softener. DEHP also cause endocrine disruptions leading to testicular cancer, genital deformations and low sperm count.
By quickly identifying the different fluorescent signatures of the different kinds of plastic, LMU's new device should prove immensely useful in recycling plants and greatly reduce the amount of plastic that ends up in landfills.
Magnetism more important to superconductivity than previously thought
August 22, 2014
Scientists have been working with superconductors for decades, but they have only recently begun to unravel some of the complicated processes that make these promising devices function. Interestingly, some of the discoveries they have made actually fly in the face of established models of how superconductors work, specifically, the presence of complex magnetic fields.
According to Claudia Cantoni, PhD, a researcher at the Department of Energy's Oak Ridge National Laboratory, "In the past, everyone thought that magnetism and superconductivity could not coexist. The whole idea of superconductors is that they expel magnetic fields, but in reality, things are more complicated."
This was first proven this past may when a group of scientists at the U.S. Department of Energy's Argonne National Laboratory first discovered a magnetic phase in iron arsenides superconductors. The new phase had never before been observed, and entirely disrupted conventional models of superconductivity.
This is not to say that these older understandings of how superconductivity works were wrong, rather, they described a different kind of device. Traditionally, conventional superconductors must be cooled to extremely low temperatures, which effectively slows down the movement of the atoms that make up the device. This allows electrons to flow more freely through the superconductor without crashing into other atoms. As an added effect, the electrons, which normally repel each other, cluster together in order to navigate the path of least resistance through the superconductor. The result is that energy transfer is more efficient since no electrons spend their potential by smashing into atoms.
In recent years, engineers have been able to create unconventional superconductors that do not need to be cooled nearly as much, yet electrons still form pairs, which seemed impossible. Although researchers were able to create devices that demonstrated these attributes, they had no idea how they worked.
One popular model of unconventional superconductor that researchers have been experimenting with is known as an iron arsenides superconductor. With this model, engineers use iron arsenides, which are normally magnetic, but when combined with sodium, the magnetism is greatly diminished. This allows the materials to become superconductive when cooled to approximately -400 degrees Fahrenheit.
The reason temperature is so important is that it affects the atomic structure of the material. At approximately 60 degrees Fahrenheit, the iron atoms rest in a square lattice, which has four-fold symmetry. However, when the material's temperature is lowered below the point of magnetic transition, the iron atoms change shape to form a rectangular lattice, and the symmetry reduces from four-fold to two-fold. This phase shift is called the nematic order, which scientists believed persisted during superconduction.
However, the Argonne researchers were surprised when they discovered that iron atoms returned two a four-fold symmetry when the material is just on the edge of superconductivity. According to Ray Osborn, an Argonne physicist on the project, "[the shift] is visible using neutron powder diffraction, which is exquisitely sensitive, but which you can only perform at this resolution in a very few places in the world." That is because the neutron powder diffraction allows scientists to pinpoint both the locations of atoms and the directions of their microscopic magnetic moments.
In addition to challenging theoretical models of superconductors, this discovery also sheds light on the question of whether nematic order is caused by magnetism or orbital ordering. According to some scientists, the orbital ordering understanding of nematic order purports that electrons tend to sit in specific d orbitals, forcing the lattice into the nematic phase. On the other hand, magnetic models of nematic phases argue that magnetic interactions drive two-fold symmetry, making them critical for superconductivity.
According to Osborn, "Orbital theories do not predict a return to four-fold symmetry, but magnetic models do."
Magnetism even more important than previously thought
While this observation seems to support a magnetic understanding of nematic order, it also opened the door for additional study of the role magnetism plays in superconduction. Following up on this potential, researchers from ORNL and Vanderbilt University have been studying the atomic-scale magnetic behavior of iron-based superconductors.
According to Cantoni, "One would think for superconductivity to exist, not only the long-range order but also the local magnetic moments would have to die out." However, by taking what can be described as an atomic snapshot, the team discovered that magnetism is actually at its maximum when superconductivity is also at its maximum.
This is an interesting discovery, considering that normally, superconductivity is diminished in strength when long-range magnetic forces, which cause atoms to align their magnetic moments on a large scale, are present. However, the ORNL study indicates that rapid fluctuations of local magnetic moments actually yield substantially different results than what was previously thought.
The team accomplished this feat with the aid of scanning transmission electron microscopy and electron energy loss spectroscopy, which were used to characterize the magnetic characteristics of individual atoms. This represents the most successful and accurate combination of observation devices ever employed to this purpose.
The thorough study took place over four years and analyzed materials across a wide spectrum of iron-based superconductors. By looking at a large sample size, the team was able to identify universal trends across different compounds. By further crunching the numbers, the researchers were able to deduce the total number and distribution of electrons in atomic energy levels, which led them to determine the approximate levels of magnetism during superconductivity.
Cantoni reports that "We find this number remains constant for all the members of this family. The number of electrons doesn't change - what changes are the positions and distribution of electrons in different levels. This is why the magnetic moment differs across families."
This represents a significant step in the advancement of nontraditional superconductor research. Historically, practical application of superconductors has been challenging due to the fact that they must be kept at such incredibly cold temperatures. This not only limits the location of their deployment, but also presents significant engineering challenges. By better understanding the role magnetism plays in alternative superconductors, it is likely that the technology could be improved and eventually implemented in the real world.
New active camouflage device adapts to its environment
August 21, 2014
Up until very recently, technology that could render objects invisible was rarely discussed outside of the realm of science fiction. However, in less than a decade, cloaking technology, as it is often referred to, has been making massive advancements thanks to the innovative research of clever scientists who have set out to turn this Star Trek trope from science fiction to science fact.
While some researchers have attempted to realize cloaking by deflecting or reflecting light, others have focused on camouflage. The two approaches are equally viable, though purists would likely insist that camouflage is not a form of cloaking. Nonetheless, the end result is comparable as both render an object effectively invisible to all but the most astute observer.
Active camouflage and cephalopods
Recently, scientists at the University of Houston have drawn inspiration from octopus to create a new kind of camouflage. Obviously, hunters and the military have been using patterns to blend into their environments for years, but the research coming out of UH is focused on creating active camouflage, which can change its appearance on the fly to blend into changing surroundings.
The new technology allows materials to automatically detect aspects of their environments and adapt to blend in. Published this week in the Proceedings of the National Academy of Sciences, the research could potentially change the face of warfare.
According to Cunjiang Yu, lead researcher and mechanical engineering assistant professor at UH, the research was inspired by the skins of cephalopods, which can quickly change their color to blend into their surroundings or to communicate with each other. The new optoelectronic camouflage device is able to detect colors and adapt to mimic those colors.
Yu claims that "Our device sees color and matches it. It reads the environment using thermochromatic material."
The UH device is currently in prototype testing, and features a simplified version that only senses black, white and shades of gray. However, Yu claims that the device could be modified to mimic a full range of colors. Furthermore, the prototype device is less than one-square inch in size, but Yu says that the size could easily be increased for more practical applications.
Perhaps one of the most interesting aspects of this new technology is that it is flexible. The device is made from a compound of ultrathin layers of material, which are embedded with semiconductor actuators, light sensors, inorganic reflectors and organic-color changing chemicals.
Octopus and squid are able to change their coloration due to meticulously constructed arrays of tiny dots of color changing tissue, like pixels on a computer monitor. According to the UH research team, their device emulates the pixelated technique that is used by cephalopods. In fact, they claim that their camouflage is a synthetic analog to octopus with the exception that it is lacking iridophores and central ocular organs.
Hiding from infrared scanners with squid proteins
This UH researchers are not the first scientists to attempt to unlock the active camouflage capabilities of cephalopods. In September 2013, a group from University of California - Irvine released their research on squids in Advanced Materials.
The UC Irvine team, led by Alon Gorodetsky, an assistant professor of chemical engineering and materials science, managed to artificially create reflectin, which is the protein responsible for a squid's ability to reflect light and change color. They were able to accomplish this feat by growing the reflectin with common bacteria to produce thin films of the color changing protein.
They found that by chemically stimulating the protein, they were able to cause the film to change its coloration and reflective properties. Although they could not dial in an exact color or reflective state, they found that when viewing the film with an infrared camera, the material would disappear and reappear as the protein's properties fluctuated.
Speaking on his research, Gorodetsky said, "Our approach is simple and compatible with a wide array of surfaces, potentially allowing many simple objects to acquire camouflage capabilities."
The UC Irvine team suggests that their material would most likely see military use due to how many defense agencies rely on infrared sensors for night vision. A soldier or military vehicle that was concealed with the synthetic reflectin would be nearly invisible to infrared sensors, thus providing a significant combat advantage.
Yu and her researchers from the University of Houston also imagine that their active camouflage device could be used by the military. The fact that the novel material is both lightweight and flexible means that it could easily be adapted for covert field operations in order to conceal special forces behind enemy lines.
Although researchers may be a long way from being able to bend light around an object to truly achieve invisibility, the recent advances in active camouflage technology are certainly raising the stakes for high tech concealment.
New technologies improve cystic fibrosis treatment options
August 19, 2014
Cystic fibrosis is a fast moving and often lethal disease, but new research over the past few months should allow for much more aggressive treatment. Back in June, researchers from Queen's University in Belfast developed a breakthrough, combined therapy that improves lung functionality and reduces the rate of hospitalizations for patients with cystic fibrosis. This development was recently followed up by new research from Monash University, where researchers have developed an X-ray imaging system that allows doctors to more closely and quickly evaluate the effectiveness of treatment in cystic fibrosis patients, a process that was previously cost and time intensive.
Working with partners in the United States and Australia, Stuart Elborn of Queen's University Belfast pioneered a new treatment for cystic fibrosis back in June. In testing, Elborn and his colleagues focused on the drugs ivacaftor and lumacaftor. In two Phase 3 studies, which included over 1,100 cystic fibrosis patients, worked from previous research on G551D patients' reactions to ivacaftor. Previously, most cystic fibrosis drugs merely treated symptoms, but ivacaftor actually treats the underlying causes of the disease. Also, the market-ready drug can treat the celtic gene mutation, which is only carried by approximately 10-15 percent of patients of Irish descent.
The recent testing examined the treatment of cystic fibrosis patients with two copies of the F508DEL mutation, which is accounts for almost 50 percent of all cases of the disease. The results were interesting since they discovered that a combination of ivacaftor and lumacaftor was more effective at improving lung functionality, in some cases as much as 2.6 to 4 percent.
Speaking on his research, Elborn said," This is a very significant breakthrough for people with cystic fibrosis. While we had previously found an effective treatment for those with the celtic gene, this new combination treatment has the potential to help roughly half of those with cystic fibrosis, those who have two copies of the F608DEL mutation."
However, there remained one problem, the effectiveness of cystic fibrosis treatment is surprisingly hard to track. Historically, the disease has been tracked by symptoms. As such, most medicine has focused on relieving those symptoms. But without accurate readings of the actual lung tissue, which is both invasive and time intensive, it can be hard to determine how much of a difference treatment is actually making.
With cystic fibrosis, timing is everything. Treatment that alleviates symptoms may provide immediate relief, but unless the underlying causes are addressed, then the disease can quickly lead to death. With this in mind, Kaye Morgan, PhD, of Monash University in Melbourne, Australia, developed an x-ray imaging method that allows researchers to look at soft tissue structures such as airways, lungs and the brain. These structures are normally invisible to conventional x-ray images, so they have traditionally required the use of invasive or slow procedures.
According to Morgan, "At the moment, we typically need to wait for a cystic fibrosis treatment to have an effect on lung health, measured by either a lung CT scan or breath measurement, to see how effective that treatment is. However, the new imaging method allows us for the first time to non-invasively see how the treatment is working 'live' on the airway surface."
This is especially valuable data for the treatment of cystic fibrosis. Considering the importance of speed and accuracy in regards to therapy, this imaging will allow doctors to cycle very quickly through treatment options by discarding ineffective methods as soon as they fail to yield positive results.
The new imaging method was developed using a synchrotron x-ray source, and it may see wider usage outside of cystic fibrosis. Given that it allows doctors to observe organs that were previously rendered invisible to most imaging methods, it should open new avenues for the treatment of other lung, heart and brain diseases.
Recycled lead from car batteries to fuel perovskite solar panels
August 18, 2014
According to Duke University's Center for Sustainability and Commerce, Americans generate 220 million tons of waste each year, and 55 percent of that ends up in landfills. For many researchers across a plethora of disciplines, reducing the amount of waste that ends up in landfills has been a longstanding goal. There are two main ways to accomplish this. One is to produce less waste, but given the United States' consumer culture, this does not seem likely. The other is to recycle trash into useful objects or materials. Most people know that you can recycle aluminum cans and plastic bottles, but new research from MIT will soon allow for the recycling of depleted car batteries by turning them into solar panels.
Old lead, new tech
Recently, Angela M. Belcher, PhD, Paula T. Hammon, PhD and a handful of graduate students at MIT has described this novel system in the journal Energy and Environmental Science. The science is based on the unique properties of perovskite, a mineral that is making waves because of its remarkable potential for solar panels. Perovskite, specifically, organolead halide perovskite, has been used to great effect in making affordable, highly efficient solar cells. In just a few years, perovskite went from being an obtuse mineral, to one of the most promising materials in solar research. Already, researchers have been able to make photovoltaic cells that have close to a 19 percent power-conversion efficiency, which is nearly equivalent with some of the best silicon-based solar cells currently available on the market.
However, perovskite solar cells require the use of refined lead, which, though relatively innocuous, needs to be processed from raw ore. This procedure creates significant toxic residue, which has led early studies into perovskite as a material for the construction of solar cells have identified the use of lead as a major problem. However, by taking advantage of abundant sources of refined lead from car batteries, this potential issue becomes insignificant.
This research represents more than an alternative source of lead. If acted on, this recycling method will reduce the number of car batteries dumped in landfills significantly. More importantly, this is not a compromise or a second-rate solution. Since the perovskite photovoltaic material is only a thin film that is less than half a micrometer thick, the MIT research demonstrates that the lead from a single car battery could produce enough solar panels to power as many as 30 households. Perovskite solar cells are fairly simple to produce, and it will be even easier if engineers can supply their factories with recycled lead from batteries instead of needing to refine it from raw ore.
Phasing out batteries
This comes at a fortuitous time for both the industries of solar panels and automobiles. According to the U.S. Energy Information Administration, there were 1,191,786 alternative fuel vehicles in use in 2011. That number has risen significantly in the past three years, especially with the introduction of electric car manufacturers like Tesla to the market. With this technology trending, it is only a matter of time before old-fashioned lead car batteries are a thing of the past.
According to Belcher, "Once the battery technology evolves, over 200 million lead-acid batteries will potentially be retired in the United States, and that could cause a lot of environmental issues."
Car batteries have been recycled for years, but according to the article, 90 percent of the lead recovered from recycled car batteries is used to make new batteries. However, when the market for lead-acid batteries deflates, then there will be no devisable purpose for depleted batteries. It is very likely that without this research, many of those batteries would end up in landfills where the lead would seep into ground water, causing significant environmental problems in the surrounding areas.
If turned into solar panels, the lead would be fully protected by other materials, such as perovskite. This would contain the lead, keeping it from seeping and causing problems. When the solar cell is eventually retired, the lead could easily be retrieved and recycled into new solar cells since the lead would still be entirely reusable.
Belcher and her team hope that their solution to the lead problem will be adopted by perovskite photovoltaics scientists, especially since their research demonstrates that recycled lead is just as potent and usable as freshly refined lead.
As more factories are beginning to consider the very real possibility of mass producing perovskite solar panels in the near future, the potential for the use of car batteries could be a game changer.
Solar power is one of the hottest new trends in alternative energy. Nearly every state in the country has initiated some kind of solar incentive plan, and it's not likely to slow down anytime soon. Perovskite solar panels will make this technology even more widely accessible. By using recycled car batteries, manufacturers will be removing toxic chemicals from landfills while providing affordable green energy.
New sensors run on sweat, charge biobatteries
August 14, 2014
In the next few years, wearable tech will be nearly ubiquitous, especially in gyms. Sensors and smartwatches will be able to give users massive amounts of data regarding their heart rate, blood sugar levels and now, thanks to new research from the University of California San Diego, lactate levels. However, these wearable sensors will do more than measure lactate levels during exercise, they will be powered by the naturally occurring biochemical.
At a recent gathering of the American Chemical Society, Joseph Wang, PhD, of UCSD presented his work on biosensors. The tiny, unobtrusive devices are as easily applied to skin as a temporary tattoo, so they can monitor levels of lactate, a form of lactic acid that is released in sweat. Lactate is a product of anaerobic metabolism, which is a process that bodies employ to provide muscles with energy when oxygen is not readily available.
Normally, the testing process for measuring lactate levels are cumbersome and intrusive. Most commonly, blood must be drawn and tested in a laboratory setting. This means that results are never instantaneous, and not likely to provide relevant information in the short term.
Wang's biosensors accurately measure lactate levels on the fly, giving athletes relevant information regarding their body chemistry over the course of their exercise. According to the press release by the ACS, test results on 10 volunteer test subjects indicated that the flexible sensors could accurately measure lactate levels from sweat during exercise.
Armed with this information, athletes can determine when they are close to reaching critical levels of lactate. When too much lactate accumulates in a person's body, his or her muscles will eventually seize and stop working. This is not only painful, but massively detrimental. This technology would allow athletes to monitor their levels and adjust their exercise accordingly so as to avoid critical failure.
Running on sweat
This breakthrough would be impressive on its own, but with additional engineering research and development Wang and his team quickly figured out how to improve on the biosensor. Not only can the device measure lactate levels, but it can actually use the lactate it gathers to power a battery. The more lactate a person produces, the more power the sensor can generate.
The sweat powered biobattery functions by passing current from an anode to a cathode, like any battery. But unlike normal batteries, Wang's device features anodes containing an enzyme that strips electrons from lactate. Those electrons then flow to the cathode, creating a current.
According to the UCSD research, most people can generate 70 microwatts per square centimeter of skin. However, in its current configuration, the biobattery's electrodes are only 2 by 3 millimeters, so they can only generate approximately 4 microwatts of power. Wenzhao Jia, PhD, one of the other researchers working on the lactate sensor, admits that "The current produced is not that high, but we are working on enhancing it so that eventually we could power some small electronic devices." Watches, for example, require 10 microwatts, so it may soon be possible to run a watch off of sweat.
Wearable sensors are trending as one of the most popular emerging technological innovations. If the hype is to be believed, smartwatches and health monitors will be able to help people manage their well-being and optimize their workouts. These devices could soon read blood sugar levels, heart rates and even caloric intake and burn. However, considering that many are meant to be worn as close to 24/7 as possible, the question of how to power them remains an issue. Devices that can run on sweat would prove especially useful for athletes, like marathon runners, who might not have the opportunity to stop and charge their sensor in the middle of a race. Instead, it would charge constantly as long as they were sweating and producing lactate.
2 new methods of creating clean energy from biomass waste and methane
August 13, 2014
Landfills are most often associated with their unbearable stink, but a new procedure could transform the offending gases into clean electricity by way of fuel cells. In related news, a team of researchers have developed a method for extracting gas from waste biomass, adding yet another level of use to what is fast becoming one of the hottest energy industries in the world.
Methane to hydrogen
In a paper to be presented at the 248th National Meeting of the American Chemical Society, the Brazil-based research team has announced a new method of extracting hydrogen from methane. Hydrogen is a paradigm of clean fuel. When run through a specialized fuel cell, hydrogen transforms into electricity, and the only waste product is water vapor.
Led by Fabio B. Noronha, PhD, of the National Institute of Technology in Rio de Janeiro, the researchers sought to solve a basic chemistry equation that had previously proven challenging to accomplish. On paper, it is possible to balance an equation such that methane and carbon dioxide can be turned into hydrogen and carbon monoxide. Without the proper catalyst, the process takes a prohibitively long amount of time. Unfortunately, carbon formed in the procedure binds onto the catalyst, making it ineffective.
As a work-around, Noronha and his team developed a self-cleaning catalyst using perovskite oxide supported on ceria, a ceramic component. Based on existing automotive technology for controlling emissions, this custom-made catalyst material is able to purge carbon from the system as soon as it is formed.
At the moment, the Brazilian scientists are conducting lab tests on the catalyst, but they believe that a new, highly stable version of the perovskite and ceria catalyst will soon be ready for commercialization and mass production. The next phase of testing, barring any unexpected surprises, will take place in a local landfill.
Landfills provide the ideal environment for testing the new technique since they are rich sources of free methane gas. If the method of hydrogen production is successful, then it may pave the way for most extensive use of hydrogen fuel cells, which are a promising method of clean energy production.
Biomass waste to gas
A team of researchers from Universiti Teknologi MARA has also taken steps toward transforming otherwise useless waste materials into useful fuels. As more countries move away from fossil fuels, biomass based fuels are becoming increasingly popular. One of the more promising attributes of biomass is that it can be produced nearly anywhere. In the United States, for instance, corn has proven an effective base crop for creating ethanol. Elsewhere in the world, researchers have experimented with maple, bamboo and even municipal solid wastes. While biofuels are a viable alternative to fossil fuels, they still produce a massive amount of organic waste.
The scientists from UiTM saw potential in the waste left behind by biofuel production, and sought to make something of it. Led by Mohamad Asadullah, PhD, the team focused their sights on oil palm biomass, which is a common crop in Asian countries for creating biofuel. By using gasification, the scientists postulated, they could extract every ounce of energy potential from the waste left over from turning oil palm into biofuel.
However, they were faced with a major problem: most common gasification processes yield gases with high concentrations of impurities like tar, dust and acidic gases, which would render any product nearly useless. These materials often contain these impurities because the process of gasification requires the use of extremely hot liquids, such as tar or molten metal, which can add unwanted components to the resultant gas.
Asadullah and his team have purportedly devised a method of gasification that removes these unwanted impurities from the final product. Although the press release from Asia Research News is unfortunately vague regarding the methods by which Asadullah has accomplished this feat, the possibility of turning waste biomass into high quality gas is promising. Such gas could be used in various applications from internal combustion engines to fuel cell power generation.
Although fossil fuels are still the most widely used type of fuel, the fact that researchers are actively pursuing alternatives is nothing if not positive. More importantly, none of these alternative fuels are restricted to one geographical point of origin. Every country in the world has landfills, so everyone has equal access to methane. Similarly, just about any agricultural region can grow an array of biofuel crops, making such a method of energy production equally viable. As such, it is noteworthy that the gasification methods developed by Asadullah and his team is equally applicable to just about any other form of biomass as it is to oil palm. Indeed, it is possible that even municipal solid waste, which is largely biomass, could be gasified, reducing the amount of trash that is stored in landfills while creating useful gases.
Scientists develop water-based "tractor beam"
August 12, 2014
This week, science fiction became science fact when physicists from The Australian National University created what can only be described as a water-based "tractor beam," not unlike the ones featured in Star Trek. Contrary to previous models that have been used to propose a theoretical method of generating tractor beams, the ANU physicists employed waves rather than lasers to create vortices that can draw in small objects.
Photonics and lasers
In 2012, a team from The Agency for Science, Technology and Research published some data on the theoretical construction of a device that could use lasers to pull or push particle size objects. The microscale experiment was based on the work of Albert Einstein and Max Planck, which stated that light carries momentum. As such, light is able to enact a small amount of force on anything it comes in contact with, but particles are the only objects small enough to be affected by this force. However, this usually scatters the beam of light, meaning that although it can push things away, it cannot effectively draw things in, which is the defining attribute of a tractor beam.
The researchers from ASTAR, led by Haifeng Wang, worked with a novel form of laser, called a Bessel beam. These lasers feature a unique distribution of light intensity across the beam, which gives the beams peculiar properties. Instead of pushing a particle forward upon impact, the light from Bessel beams scatters forward. The result is that the particle is actually drawn toward the point of the beam's origin, not away from it.
Back in 2012, Wang and his co-workers acknowledged the limitations of such a device. Although they were able to prove their theory that objects could be moved with a laser, the scale of the objects their tractor beam was able to move was such that real world application would be extremely unlikely. Although a scaled up and refined version of the Bessel beam device could conceivably be used in nanoengineering or to manipulate biological cells on a micro level, it would never be able to move something as large or complex as a car or a person. That is because the laser intensity required to move larger objects would likely destroy the thing it was trying to move.
Water and waves
The scientists at ASU took a different approach to the problem of creating a functional tractor beam. Rather than use lasers to move things through the air, the research team elected to use waves to move things through water. In their experimentation, the group, which was led by Michael Shats, PhD, and Horst Punzmann, PhD and professor at ANU's Research School of Physics and Engineering, discovered that they could use wave generators to control water flow patterns. With the correct manipulation, they further realized that they could move objects in the water in any direction.
According to Punzmann, "We have figured out a way of creating waves that can force a floating object to move against the direction of the wave."
The press release from ANU includes a video of the scientists controlling the movement of a ping-pong ball in a wave tank in which the size and frequency of the wave patterns were manipulated to push the ball away and pull it back in. This phenomenon, which has not yet been fully explained, occurs because the waves generate tiny currents on the surface of the water, which can draw items in or push them away depending on the flow.
Although a large scale version of this device does not yet exist, the real world applications of ANU's water tractor beam technology are promising. For instance, it could be used to control oil spills or manipulate other floating debris. Of course, on a much larger scale, it could be used to draw in ships, thus fully actualizing its sci-fi roots.
Synthetic cilia move water, deflect light
August 6, 2014
Inspired by nature, MIT engineers have designed a novel material that features microscopic, magnetic hairs embedded in an elastic skin-like compound. These hairs act like cilia, and can be manipulated with a magnetic field to move materials in any direction, including up, against gravity.
The tiny metallic hairs are made of nickel and fixed to an clear, stretchable layer of silicon. The microhairs, measuring a mere 70 microns high by 25 microns wide, are arranged in such a configuration that they are able to pass material between each other. The team that designed and fabricated the metal hair and silicon material was led by associate professor of mechanical engineering Evelyn Wang, Rong Xiao, a former graduate student and Dion Antao, a postdoc student.
By oscillating, the synthetic microstructures act can act like the hairs in a human nose or the cilia that line intestines. In noses, hairs are moved by a person's breath to brush foreign debris like dust out of the nasal passages. Similarly, intestinal cilia move and absorb nutrients as they are passed through the digestive system. Yangying Zhu, a graduate student in MIT's Department of Mechanical Engineering, explained the origin of the project.
"We see these dynamic structures a lot in nature, so we thought, 'What if we could engineer microstructures, and make them dynamic?' This would expand the functionality of surfaces."
In order to accomplish this feat, the research team made molds for the tiny hairs. They then filled these molds with nickel before carefully dissolving the molds, leaving microscopic pillars of nickel. Next, they bonded the nickel hairs to a pliant base of silicone, which allowed the metal to move when affected by magnetic force. By controlling the electromagnet, the researchers were able to get uniformly consistent movement from the synthetic cilia, which let them move materials like water.
In testing, the MIT researchers focused on moving droplets of water with the synthetic, magnetic hairs. The experiments involved carefully placing droplets of water onto the microhair array with a syringe. A video attached to the press release from the university clearly shows water changing its direction and even flowing against gravity as it is carried by the metallic hairs.
Experimenting on the new material, the engineering research team also discovered that it could affect light as well. The hairs are able to deflect light differently depending on its angle, which can be altered on an infinitesimally small scale through the use of magnetic waves. Zhu noticed this when shining a laser through the materials and modifying the angle of the hairs. She noticed that the sharper she made the angle, the less light was able to move through the material.
As a method of transporting materials across the surface of an object, the MIT engineers see potential use for the material in lab-on-a-chip devices. The magnetic nickel pillars could be manipulated to direct the flow of cells and other biological materials through a medical chip. They also speculate on the function of this material in the fabrication of water resistant materials like windshields and raincoats that would move water and other debris.
With the discovery of its properties of light deflection, the microhair arrays could also be used to create smartwindows that can be programmed to let in more or less light by manipulating a magnetic field. As an alternative to shades or blinds, smartwindows would maintain relative translucence while limiting the amount of solar radiation allowed through the glass. Such a material could be controlled by autonomous systems, and would require less energy to operate than blinds, which would require a motor if they were automated.
New advances in biofuel could save American farming
August 4, 2014
Efficient biofuel has been a goal of chemists and farmers alike for years, and it may finally be in sight. This week, teams at Kansas State University and University of California at Riverside have made significant advances toward creating cost-efficient biofuels that could be used in existing technology without any modifications. Although the dream of free energy from alternative energies like solar and wind is ultimately more sustainable, biofuels would serve as an effective bridge to zero emissions cars, power plants and factories.
The two schools, working independently from one another, have provided valuable data that could be used to solve two challenges of biofuel. The team at Kansas State took a more agricultural approach to creating more efficient biodiesel. Led by Timothy Durrett, an assistant professor of biochemistry and molecular biophysics, the KS researchers have developed a new strain of Camelina sativa, a non-food oil seed that can be used to create less viscous biodiesel. The researchers at UC Riverside, on the other hand, have set their efforts to developing a versatile, non-toxic method for converting raw agricultural and forestry wastes into biofuels and other valuable chemicals.
Running on vegetable oil
In terms of existing technologies, diesel engines are surprisingly effective at running on biofuels as simple as vegetable oil. However, in addition to smelling like a fast food restaurant, diesel engines running on vegetable oil quickly seize up due to the high viscosity of the fuel. As such, the oil needs to be converted to biodiesel through a relatively expensive process if it is to be used in existing technologies. Alternatively, engineers could conceivably design an engine that could run on high viscosity vegetable oil, but such a device has not yet been invented.
Durrett and his team concocted another solution. Since vegetable oil is too thick, they set out to figure out an alternative oil that is thinner. To this end, they began working with Camelina sativa, an oilseed that requires very little irrigation and fertilizer, and can be synthesized to create a substance not unlike vegetable oil, but significantly less viscous, making it a suitable drop in fuel for diesel engines.
Speaking on his work on Camelina sativa, Durrett said that "By reducing the viscosity, we want to make a biofuel that can be used directly by a diesel engine without requiring any kind of chemical modification. We would be able to extract the oil directly and use it in a diesel engine right away." This process completely circumvents the problem of refining organics into biodiesel since the vegetable oil can be safely burned in diesel engines without negative effects.
This crop could also come as a boon to farmers, particularly those who grow wheat. Carnelina sativa requires very little water or fertilizer, so it can be grown just about anywhere, even in extreme conditions. Furthermore, it can be cycled with wheat since it does not require the same nutrients as the staple food crop. This could prove invaluable for farmers in drought-ridden regions, like California. Not only would farmers be able to sell the raw product, but they could also run their farm equipment on the very oil they harvest.
Better living through chemistry
On the other side of the spectrum, the team from UC Riverside, which was led by Charles E. Wyman, PhD, relied much more heavily on chemistry than nature. In an effort to make the production of biofuels more cost-efficient, the Californian researchers developed a process known as Co-solvent Enhanced Lignocellulosic Fractionation, which has purportedly struck the Goldilocks zone of cost and yield.
By using tetrahydrofuran as a co-solvent, the team was able to break down raw biomass feedstocks and produce high yields of primary and secondary fuel precursors. Significantly, they were able to accomplish this at relatively moderate temperatures, further lowering the cost of the procedure. These precursor fuels are essentially chemical building blocks that can either be further refined into ethanol or drop-in fuels that can be customized to function either as conventional gasoline, jet fuel or diesel.
Tetrahydropfuran has proven so effective at transforming biomass into fuel thanks to several unique qualities: it mixes homogenously with water, has a low boiling point and can be recovered for additional use at the end of the process. Additionally, it allows for modifications of the Co-solvent Enhanced Lignocellulosic Fractionation process that can be employed to create different end products, namely the aforementioned fuel varieties.
To achieve these results, lignocellulosic biomass, which is one of the most abundant organic materials on the planet, is broken down into hydroxymethylfurfural, furfural and lignin. The hydroxymethylfurfural and furfural can both be synthesized into combustible liquid fuels. The lignin, though often burned as waste, can also be retrieved for additional use in synthesized biofuels, though the press release was not specific as to exact nature of these fuels.
In their flagship experiment for this research, the team from UC Riverside dissolved maple using their patent-pending procedure and iron chloride, a type of metal halide. Impressively, the researchers were able to obtain yields of 95 percent of the theoretical maximum for furfural and 51 percent of the theoretical maximum for hydroxymethylfurfural in a single pot reaction. This represents an improvement of nearly half again that achieved by current commercial technologies. Of note is the fact that this breaks the price point of fossil fuels, making biofuel more ecologically and economically viable than crude oil.
Saving America's farms
Both the research from Kansas State and UC Riverside should come as welcome news to America's farmers who have been struggling through some of the worst droughts since the dust bowl of the 1930s. Kansas State presents a new cash crop that can be grown with very little resources, which could potentially drag many at risk farms out of the red and into profitable margins. The research from UC Riverside, on the other hand, should allow for the monetization of any growth, even if it fails as its intended crop. Using Co-solvent Enhanced Lignocellulosic Fractionation, any plant material could potentially be turned into biofuel. This means that farmers could sell harvest waste, failed crops or waste surplus to help curb their losses while providing the building blocks for valuable biofuels.