After demonstrating the first acoustically driven tractor beam platform, researchers develop a simpler, cheaper version using 3-D printable parts and open-source electronic components for the maker community
Last year Asier Marzo, then a doctoral student at the Public University of Navarre, helped develop the first single-sided acoustic tractor beam — that is, the first realization of trapping and pulling an object using sound waves from only one direction. Now a research assistant at the University of Bristol, Marzo has lead a team that adapted the technology to be, for all intents and purposes, 3-D printable by anyone (with some assembly required, of course).
In addition to a fully detailed how-to video that the group produced for the public, the results of the work developing this do-it-yourself, handheld acoustic tractor beam will appear this week as an open access paper in Applied Physics Letters, from AIP Publishing.
Sonic levitation is not new, and the use of sound waves to push around macroscopic objects, or create patterns in resting sand and flowing water, is scattered throughout YouTube and has been for years. This technology, however, is not simply sonic levitation, using sound to push objects around.
Based on similar fundamental physics used for decades to create optical traps, these tractor beams are true to their name in that they pull objects, trapping small beads — and even insects — at their foci.
“The most important thing is that it can attract the particle towards the source,” said Marzo. “It’s very easy to push particles from the source, but what’s hard is to pull them toward the source; to attract the particles. When you move the tractor beam, the particle moves, but otherwise the trap is static. It can levitate small plastics; it can also levitate a fly and small biological samples. It’s quite handy.”
The first versions of the device that proved the concept possible were not much larger than these new, 3-D printable versions. However, their underlying technology was more complex and required expensive electronics.
Much of the expense arose from the array of active components that electronically shaped sound waves, manipulating how and where they interfere to create the resulting object-trapping environment just above the array.
“Previously we developed a tractor beam, but it was very complicated and pricey because it required a phase array, which is a complex electronic system,” Marzo said. “In this paper, we made a simple, static tractor beam that only requires a static piece of matter.”
The simplicity (and affordability) of this passive, static-matter approach comes from the special architecture of that matter, designed to replace the phase array components and to shape sound waves structurally instead of electronically. As the sound, which now can be generated from a single source, passes through these carefully designed elements, the waves are shaped by the internal structure of the 3-D printed material.
“We can modulate a simple wave using what’s called a metamaterial which is basically a piece of matter with lots of tubes of different lengths. The sound passes through these tubes and when it exits the metamaterial, it has the correct phases to create a tractor beam,” said Marzo.
With an effect that is primarily determined by the shape of the tubes, the research team focused on optimizing the design to allow fabrication with common 3-D printers, ensuring it could be constructed even by at-home hobbyists.
According to Marzo, this was primarily a challenge in resolution, requiring a design that would not suffer from the limited precision of lower-end 3-D printer nozzles. “We needed to engineer the tubes very well to allow them to be 3-D printed with a normal 3-D printer. A normal 3-D printer has a lot of limitations,” he said.
With those limitations overcome, the group developed the rest of the tractor beam system using easily accessible components, such as from the popular open-source electronics supplier, Arduino. They even produced a detailed how-to video for its construction, a link to which is included below. “There will be a set of instructions with a list of the needed components and a step-by-step video. The components are very simple, like an Arduino and a motor driver, and everything can be bought on Amazon for less than £50 (about $70),” Marzo said.
Besides seriously impressing dinner guests, these DIY tractor beams have many potential uses and may even become a new tool for studying low-gravity effects on biological samples. Marzo pointed out this type of “micro-gravity” research is already of interest and encouraged biologists to find their own applications for the device.
“Recently there have been several papers about what happens if we levitate an embryo, how does it develop? Or what happens if we levitate bacteria?” he said. “For instance, they discovered salmonella is three times more [virulent] when it’s levitated. Certain microorganisms react differently to microgravity.”
There are three designs of the device, each with trapping profiles suitable for different object sizes relative to the wavelength of sound used. However, even for the full lab implementation where the group traps heavier objects and even liquids, trapping objects larger than half the wavelength of sound still poses a challenge. For practical frequencies, just above what humans can hear, this limits the size of trappable objects to a few millimeters.
As Marzo and his group work to overcome this challenge and continue to improve the capabilities of their tractor beams, the democratization of their technology paves the way for untold uses and tweaks from the maker community. So, the question really is — what would you do with your own tractor beam?
Learn more: How to 3-D Print Your Own Sonic Tractor Beam
Controls engineers at UC San Diego have developed practical strategies for building and coordinating scores of sensor-laden balloons within hurricanes.
Using onboard GPS and cellphone-grade sensors, each drifting balloon becomes part of a “swarm’’ of robotic vehicles, which can periodically report, via satellite uplink, their position, the local temperature, pressure, humidity and wind velocity.
This new, comparatively low-cost sensing strategy promises to provide much-needed in situ sampling of environmental conditions for a longer range of time and from many vantage points within developing hurricanes. This has the potential to greatly improve efforts to estimate and forecast the intensity and track of future hurricanes in real time.
Current two to five day forecasts of many hurricanes deviate significantly from each other, and from the truth. For example, as Hurricane Matthew churned toward the eastern seaboard in early October of 2016, various news outlets reported “forecasts” like “Hurricane Matthew will probably make landfall somewhere between Charleston and Boston, so everyone brace yourselves.”
“Guidance like this is entirely inadequate for evacuation and emergence response preparations,” said Thomas Bewley, a professor at the Jacobs School of Engineering at UC San Diego and the paper’s senior author.
Improved forecasts, to be greatly facilitated by improved in situ environmental sampling, are essential to protect property and save lives from such extreme environmental threats, he added.
Key challenges in this effort include the design of small, robust, buoyancy-controlled balloons that won’t accumulate ice; the efficient coordination of the motion of these balloons to keep them moving within the hurricane, between an altitude of 0 and 8 kilometers (about 5 miles); and to keep them well distributed over the dynamically significant regions within the hurricane, for up to a week at a time.
Bewley and UC San Diego post-doctoral researcher Gianluca Meneghello detail various aspects of their work on this problem in the October 2016 issue of the Physical Review Fluids, building upon work they published in the proceedings of the eighth International Symposium on Stratified Flows (ISSF) in San Diego, (Sept. 1, 2016). They plan to expand on their work at the forthcoming IEEE Aerospace Conference in Big Sky, Mont. (March 6, 2017).
|Typical spread of the zero- to five-day forecasts of the track of Hurricane Matthew, as performed by the major hurricane forecasting centers on (left) Oct 3, (middle) Oct 6, and (right) Oct 7, 2016.|
Data from http://www.emc.ncep.noaa.gov/gc_wmb/vxt/HWRF/tcall.php?selectYear=2016&selectBasin=North+Atlantic&selectStorm=MATTHEW14L
How the model works
The model for large-scale coordination of balloon swarms within hurricanes, as discussed in the Physical Review Fluids article, uses a clever strategy to model predictive control by leveraging the cutting-edge Weather Research and Forecasting code developed by the National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration and the Air Force Weather Agency (AFWA). Multiple simulations indicate the remarkable effectiveness of this approach, including a simulation based on the evolution of Hurricane Katrina as it moved across the Gulf of Mexico, as summarized in the video available at http://flowcontrol.ucsd.edu/katrina.mp4
`The key idea of our large-scale balloon coordination strategy,’’ said Bewley, “is to `go with the flow,’ commanding small vertical movements of the balloons and leveraging the strong vertical stratification of the horizontal winds within the hurricane to distribute the balloons in the desired fashion horizontally.”
Intermediate-scale and small-scale fluctuations in the violent turbulent flow of a hurricane, which are unresolved by forecasting codes like WRF, are quite substantial. The researchers’ strategy? “We simply ride out the smaller-scale fluctuations of the flow,” said Meneghello. “The smaller-scale flowfield fluctuations induce something of a random walk in the balloon motion. We model these fluctuations statistically, and respond with corrections only if a balloon deviates too far from its desired location in the formation.”
Background on the project
As summarized in their ISSF paper, the researchers’ strategy for applying such corrections, dubbed Three Level Control (and endearingly abbreviated TLC), applies a finite shift to the vertical location of the displaced balloon for a short period of time, again leveraging the strong vertical stratification of the horizontal winds to return the balloon to its nominal desired location.
A third essential ingredient of the project, summarized in the researchers’ IEEE paper, is the design of small (about 3 kg or 6.5 lbs.), robust, energetically-efficient, buoyancy-controlled balloons that can survive, without significant accumulation of ice, in the cold, wet, turbulent, electrically active environment of a hurricane. The balloons can operate effectively for up to a week at a time on a battery charge not much larger than that of a handful of iPhones. “Cellphone-grade technologies, for both environmental sensors as well as low-energy radios and microprocessors, coupled with new space-grade balloon technology developed by Thin Red Line Aerospace, are on the cusp of making this ambitious robotic sensing mission feasible,” said Bewley.
Control theory applied
In addition to robotics, Bewley’s team specializes in the field of control theory, which is the essential “hidden technology” in many engineering applications, such as cruise control and adaptive suspension systems in cars, stability augmentation systems in high-performance aircraft and adaptive noise cancellation in telecommunication. Control theory made it possible for SpaceX rockets to land on barges at sea.
Though the math and numerical methods involved are sophisticated, the fundamental principle is straightforward: sensors take measurements of the physical environment, then a computer uses these measurements in real time to coordinate appropriate responses by the system (in this case, the buoyancy of the balloons) to achieve the desired effect.
Bewley, Meneghello and colleagues are now working towards testing the balloons and algorithms designed in this study in the real world. With sensor balloon swarms and the special TLC coming out of their lab, fire and safety officials may soon have a crucial extra couple of days to move people out of harm’s way, and to prepare emergency responses, when the next Katrina or Sandy threatens.
AlbertaSat will bring home world-class data using smaller-than-ever instruments with the fluxgate magnetometer on the Ex-Alta 1 CubeSat.
Smaller, faster, cheaper—miniaturised space technology opens the door to future University-based space exploration.
Researchers with the University of Alberta’s AlbertaSat team present the miniature fluxgate magnetometer, destined to go where no such magnetometer has gone before atop the Ex-Alta 1 CubeSat set for launch in spring 2017.
Designed and built by faculty and students with the University of Alberta Faculty of Science and Faculty of Engineering, the modern, low-cost, and miniature instrument will facilitate cutting-edge space research conducted from its place on-board cube satellites.
Democratizing the space race
“Historically, space research has used one, or at most a handful, of large, expensive spacecraft to explore near-Earth space and our solar system,” explains David Miles, PhD candidate in the Department of Physics and principal investigator for the instrument. “While this has provided stunning insight into our planet and our solar system, it necessarily gives a limited and incomplete picture.”
Nanosatellite technology, such as the fluxgate magnetometer, ushers in the next generation of space research which in future can open the door to swarms of miniaturised spacecraft encircling the Earth.
“Imagine trying to understand and predict the path hurricanes with only a few weather stations dotted around the world” said Ian Mann, professor in the Department of Physics and the co-lead for Ex-Alta-1. “That’s the current challenge for accurate space weather forecasting in the vastness of space around the Earth. However, miniaturised technology would enable swarms of perhaps hundreds of spacecraft or more to pin-point the potentially destructive paths of space storms.”
Weathering the storm
The newest space science instrument from the University of Alberta is a novel fluxgate magnetometer which will fly into space atop AlbertaSat’s Ex-Alta 1 CubeSat early next year. The miniature, low-cost instrument will take world-class measurements of the near-Earth magnetic field which influences space weather, demonstrating the potential of nanosatellite technology to significantly reduce barriers to entry and democratize the space race.
“Once we have a flight-proven instrument, we have several international collaborators interested in flying our instrument for their own research,” says Miles. “Tens or even hundreds of spacecraft can provide a dynamic, three-dimensional, and high-resolution picture of the space we inhabit, thereby improving the understanding of such threating space weather storms.”
Researchers at the University of Alberta have opportunities for undergraduate and graduate students to participate in this new space race using hands-on space research involving modelling, data analysis, meteorites, high-altitude balloons, sub-orbital rockets, and CubeSat missions. Interested students should contact the University of Alberta’s Institute for Space Science, Exploration and Technology.
A West Virginia University mathematics researcher has developed an algorithm to mobilize unmanned aerial vehicles (UAVs) in team missions.
The new technology allows a team of UAVs to fly autonomously to complete complex coordinated missions.
“Someone on the ground sets an area to be scanned by the UAVs. Within the area, the person selects different priority points for information-gathering. The algorithm then sets what coordinates are surveyed by which UAVs, and determines a plan for them so that it also covers as much of the area as possible without depleting the battery life,” said Marjorie Darrah, whose project is funded by the Army Research Laboratory.
“The technology is not bypassing the ground station, not taking over the flight plan. It is just giving the ground station help to complete a complex mission with three planes at once.”
The new genetic algorithm is designed for the Raven, a UAV used by United States military and Special Operations Command as well as military operations in Austria, Estonia, Italy, Denmark, Spain and the Czech Republic.
More than 19,000 Ravens are in service, making them one of the most widely adopted UAV systems in the world. However, they can only be purchased in packages of three. Because they are generally flown individually, this research is an opportunity to use the technology more efficiently.
“(Ravens) are never really used in the capacity of what’s at their disposal,” Darrah said. “What we’ve developed can encourage the military to use a piece of add-on software that works along with the ground station.”
Military operations typically use UAVs for wide area searches and surveillance, enemy air defense and conducting intelligence, surveillance and reconnaissance, such as securing a military base or a specific area.
Civilian operations can also utilize UAVs in teams with the genetic algorithm. The team-approach is useful for monitoring biological threats to agriculture, detecting fires, conducting transportation surveillance and managing natural disasters.
Marcela Mera Trujillo, a mathematics graduate student in Darrah’s lab, is working to use a similar genetic algorithm approach to employ various mapping techniques in another civilian application. She is creating highly detailed, high resolution 3-D maps using multirotors that fly over structures and capture images from many different angles.
“This is an idea (Trujillo) is working on with 4-D Tech Solutions, a small business in Morgantown,” Darrah said. “It is a good model for the University to work with government labs and small business. Through a summer internship, Trujillo has helped develop a provisional patent for the 3-D mapping algorithm.”
Darrah’s research team was featured on the cover of the fall 2016 edition of DSIAC Journal, the Defense Systems Information Analysis Center’s quarterly magazine that introduces new technology to all branches of the military within the Department of Defense.
“15 years ago, this (technology) was an idea. Now it’s a reality,” Darrah said. “Now that we are seeing how the Raven is being used in many countries around the world—it’s versatile, hand-launched, robust—we can encourage people to use the technology in new ways.”
With Unmanned Aerial Vehicles (UAVs) or drones gaining popularity globally for commercial, recreational and industry purposes, hundreds of UAVs may soon be buzzing all over Singapore.
The lower cost of drones and rising demand for commercial drone services have already led to a boom in the number of drones taking to the skies in Singapore.
With Singapore’s limited airspace and dense population, the need for an aerial traffic management system to allow drones to fly safely has become more urgent.
Researchers at Nanyang Technological University, Singapore (NTU Singapore) are studying ways to allow hundreds of UAVs to fly efficiently and safely at any one time.
The aim is to develop a traffic management system for UAVs consisting designated air-lanes and blocks, similar to how cars on the roads have traffic lights and lanes.
Advanced technologies that will be developed include smart and safe routing, detect- and-avoid systems, and traffic management to coordinate air traffic.
Named Traffic Management of Unmanned Aircraft Systems, this initiative is spearheaded by NTU’s Air Traffic Management Research Institute (ATMRI).
ATMRI is a joint research centre by NTU and the Civil Aviation Authority of Singapore (CAAS). It aims to research and develop air traffic management solutions for Singapore and the Asia Pacific region, including UAV traffic management which is one of its key programmes.
Leading the research programme are NTU Professor Low Kin Huat, an expert in robotics and UAVs from the School of Mechanical and Aerospace Engineering, and ATMRI Senior Research Fellow, Mr Mohamed Faisal Bin Mohamed Salleh.
Prof Low said it is important to develop a traffic management solution for UAVs tailored to actual challenges faced by Singapore given the huge growth of UAV traffic expected over the next decade.
“At NTU, we have already demonstrated viable technologies such as UAV convoys, formation flying and logistics, which will soon become mainstream,” explained Prof Low. “This new traffic management project will test some of the new concepts developed with the aim of achieving safe and efficient drone traffic in our urban airways.”
“The implications of the project will have far reaching consequences, as we are developing ways for seamless travel of unmanned aircrafts for different purposes without compromising safety, which is of paramount importance.”
Professor Louis Phee, Chair of NTU’s School of Mechanical and Aerospace Engineering, said the UAV research at NTU is a natural progression, with the school’s deep expertise in autonomous vehicles and robotics developed over the last decade.
“This research will pave the way for appropriate rules and regulations to be implemented amidst the rapid growth of UAVs. The findings can help improve safety and address security concerns, which are especially important given today’s climate of uncertainty.”
Coordinating centres to track airborne drones
To ensure that traffic is regulated across the whole of Singapore, a possible solution is the establishment of coordinating stations for UAV traffic. These stations can then track all the UAVs that are in the air, schedule the traffic flow, monitor their speeds and ensure a safe separation between the UAVs.
Mr Faisal, the co-investigator of the programme, said various scenarios will be tested out using computer simulations and software to optimise UAV traffic routes, so as to minimise traffic congestions.
“We will also look into proposing safety standards, for instance how high UAVs should fly and how far they should be flying above buildings, taking privacy concerns and laws into consideration, and to suggest recommended actions during contingencies,” said Mr Faisal, who is also Deputy Director at ATMRI.
One proposed strategy is to use the current infrastructure such as open fields for take-off and landing and having UAVs fly above buildings and HDB flats, which can act as emergency landing sites to minimise risk to the public.
Currently, restricted airspace and zones where UAV operations are prohibited have already been identified, such as near airports and military facilities.
The researchers will test out several concepts, such as geofencing. The idea is to set up virtual fences where UAVs can be automatically routed around a restricted geographical location such as the airport.
Another important research area will be collision detection. UAVs will need to have sensors that enable detection and avoidance of collision with another UAV. This will allow UAVs to follow a set of actions to avoid any mid-air incidents, such as flying above, below, or around other UAVs.
This multidisciplinary research initiative will bring together faculty and researchers from different fields in NTU, from aerospace engineering and air traffic management to robotics and electronic engineering.
Spanning a period of four years, the project which will also tap on industry experts, is expected to complete its initial phase of conceptual design and software simulation by end 2017.
This is followed by actual test bedding of solutions using UAVs developed by NTU that can be used for relevant applications in 2018.
Instead of ordering batteries by the pack, we might get them by the ream in the future.
Researchers at Binghamton University, State University of New York have created a bacteria-powered battery on a single sheet of paper that can power disposable electronics. The manufacturing technique reduces fabrication time and cost, and the design could revolutionize the use of bio-batteries as a power source in remote, dangerous and resource-limited areas.
“Papertronics have recently emerged as a simple and low-cost way to power disposable point-of-care diagnostic sensors,” said Assistant Professor Seokheun “Sean” Choi, who is in the Electrical and Computer Engineering Department within the Thomas J. Watson School of Engineering and Applied Science. He is also the director of the Bioelectronics and Microsystems Lab at Binghamton.
“Stand-alone and self-sustained, paper-based, point-of-care devices are essential to providing effective and life-saving treatments in resource-limited settings,” said Choi.
On one half of a piece of chromatography paper, Choi and PhD candidate Yang Gao, who is a co-author of the paper, placed a ribbon of silver nitrate underneath a thin layer of wax to create a cathode. The pair then made a reservoir out of a conductive polymer on the other half of the paper, which acted as the anode. Once properly folded and a few drops of bacteria-filled liquid are added, the microbes’ cellular respiration powers the battery.
“The device requires layers to include components, such as the anode, cathode and PEM (proton exchange membrane),” said Choi. “[The final battery] demands manual assembly, and there are potential issues such as misalignment of paper layers and vertical discontinuity between layers, which ultimately decrease power generation.”
Different folding and stacking methods can significantly improve power and current outputs. Scientists were able to generate 31.51 microwatts at 125.53 microamps with six batteries in three parallel series and 44.85 microwatts at 105.89 microamps in a 6×6 configuration.
It would take millions of paper batteries to power a common 40-watt light bulb, but on the battlefield or in a disaster situation, usability and portability is paramount. Plus, there is enough power to run biosensors that monitor glucose levels in diabetes patients, detect pathogens in a body or perform other life-saving functions.
“Among many flexible and integrative paper-based batteries with a large upside, paper-based microbial fuel cell technology is arguably the most underdeveloped,” said Choi. “We are excited about this because microorganisms can harvest electrical power from any type of biodegradable source, like wastewater, that is readily available. I believe this type of paper biobattery can be a future power source for papertronics.”
The innovation is the latest step in paper battery development by Choi. His team developed its first paper prototype in 2015, which was a foldable battery that looked much like a matchbook. Earlier this year they unveiled a design that was inspired by a ninja throwing star.
Researchers at Columbia University, Princeton and Harvard University have developed a new approach for analyzing big data that can drastically improve the ability to make accurate predictions about medicine, complex diseases, social science phenomena, and other issues.
In a study published in the December 13 issue of Proceedings of the National Academy of Sciences (PNAS), the authors introduce the Influence score, or “I-score,” as a statistic correlated with how much variables inherently can predict, or “predictivity”, which can consequently be used to identify highly predictive variables.
“In our last paper, we showed that significant variables may not necessarily be predictive, and that good predictors may not appear statistically significant,” said principal investigator Shaw-Hwa Lo, a professor of statistics at Columbia University. “This left us with an important question: how can we find highly predictive variables then, if not through a guideline of statistical significance? In this article, we provide a theoretical framework from which to design good measures of prediction in general. Importantly, we introduce a variable set’s predictivity as a new parameter of interest to estimate, and provide the I-score as a candidate statistic to estimate variable set predictivity.”
Current approaches to prediction generally include using a significance-based criterion for evaluating variables to use in models and evaluating variables and models simultaneously for prediction using cross-validation or independent test data.
“Using the I-score prediction framework allows us to define a novel measure of predictivity based on observed data, which in turn enables assessing variable sets for, preferably high, predictivity,” Lo said, adding that, while intuitively obvious, not enough attention has been paid to the consideration of predictivity as a parameter of interest to estimate. Motivated by the needs of current genome-wide association studies (GWAS), the study authors provide such a discussion.
In the paper, the authors describe the predictivity for a variable set and show that a simple sample estimation of predictivity directly does not provide usable information for the prediction-oriented researcher. They go on to demonstrate that the I-score can be used to compute a measure that asymptotically approaches predictivity. The I-score can effectively differentiate between noisy and predictive variables, Lo explained, making it helpful in variable selection. A further benefit is that while usual approaches require heavy use of cross-validation data or testing data to evaluate the predictors, the I-score approach does not rely as much on this as much.
“We offer simulations and an application of the I-score on real data to demonstrate the statistic’s predictive performance on sample data,” he said. “These show that the I-score can capture highly predictive variable sets, estimates a lower bound for the theoretical correct prediction rate, and correlates well with the out of sample correct rate. We suggest that using the I-score method can aid in finding variable sets with promising prediction rates, however, further research in the avenue of sample-based measures of predictivity is needed.”
The authors conclude that there are many applications for which using the I-score would be useful, for example in formulating predictions about diseases with high dimensional data, such as gene datasets, in the social sciences for text prediction or financial markets predictions; in terrorism, civil war, elections and financial markets.
“We’re hoping to impress upon the scientific community the notion that for those of us who might be interested in predicting an outcome of interest, possibly with rather complex or high dimensional data, we might gain by reconsidering the question as one of how to search for highly predictive variables (or variable sets) and using statistics that measure predictivity to help us identify those variables to then predict well,” Lo said. “For statisticians in particular, we’re hoping this opens up a new field of work that would focus on designing new statistics that measure predictivity.”
The day of charging cellphones with finger swipes and powering Bluetooth headsets simply by walking is now much closer.
Michigan State University engineering researchers have created a new way to harvest energy from human motion, using a film-like device that actually can be folded to create more power. With the low-cost device, known as a nanogenerator, the scientists successfully operated an LCD touch screen, a bank of 20 LED lights and a flexible keyboard, all with a simple touching or pressing motion and without the aid of a battery (click the respective links to see a short video of each demonstration).
The groundbreaking findings, published in the journal Nano Energy, suggest “we’re on the path toward wearable devices powered by human motion,” said Nelson Sepulveda, associate professor of electrical and computer engineering and lead investigator of the project.
“What I foresee, relatively soon, is the capability of not having to charge your cell phone for an entire week, for example, because that energy will be produced by your movement,” said Sepulveda, whose research is funded by the National Science Foundation.
The innovative process starts with a silicone wafer, which is then fabricated with several layers, or thin sheets, of environmentally friendly substances including silver, polyimide and polypropylene ferroelectret. Ions are added so that each layer in the device contains charged particles. Electrical energy is created when the device is compressed by human motion, or mechanical energy.
The completed device is called a biocompatible ferroelectret nanogenerator, or FENG. The device is as thin as a sheet of paper and can be adapted to many applications and sizes. The device used to power the LED lights was palm-sized, for example, while the device used to power the touch screen was as small as a finger.
Advantages such as being lightweight, flexible, biocompatible, scalable, low-cost and robust could make FENG “a promising and alternative method in the field of mechanical-energy harvesting” for many autonomous electronics such as wireless headsets, cell phones and other touch-screen devices, the study says.
Remarkably, the device also becomes more powerful when folded.
“Each time you fold it you are increasing exponentially the amount of voltage you are creating,” Sepulveda said. “You can start with a large device, but when you fold it once, and again, and again, it’s now much smaller and has more energy. Now it may be small enough to put in a specially made heel of your shoe so it creates power each time your heel strikes the ground.”
Sepulveda and his team are developing technology that would transmit the power generated from the heel strike to, say, a wireless headset.
Researchers develop a simple processing technique that could cut the cost of organic photovoltaics and wearable electronics
With a new technique for manufacturing single-layer organic polymer solar cells, scientists at UC Santa Barbara and three other universities might very well move organic photovoltaics into a whole new generation of wearable devices and enable small-scale distributed power generation.
The simple doping solution-based process involves briefly immersing organic semiconductor films in a solution at room temperature. This technique, which could replace a more complex approach that requires vacuum processing, has the potential to affect many device platforms, including organic printed electronics, sensors, photodetectors and light-emitting diodes. The researchers’ findings appear in the journal Nature Materials.
“Because the new process is simple to use, general in terms of applicability and should be configurable into mass productions, it has the potential to greatly accelerate the widespread implementation of plastic electronics, of which solar cells are one example,” said co-author Guillermo Bazan, director of UCSB’s Center for Polymers and Organic Solids. “One can see impacts in technologies ranging from light-emitting devices to transistors to transparent solar cells that can be incorporated into building design or greenhouses.”
Studied in many academic and industrial laboratories for two decades, organic solar cells have experienced a continuous and steady improvement in their power conversion efficiency with laboratory values reaching 13 percent compared to around 20 percent for commercial silicon-based cells. Though polymer-based cells are currently less efficient, they require less energy to produce than silicon cells and can be more easily recycled at the end of their lifetimes.
This new method, which provides a way of inducing p-type electrical doping in organic semiconductor films, offers a simpler alternative to the air-sensitive molybdenum oxide layers used in the most efficient polymer solar cells. Thin films of organic semiconductors and their blends are immersed in polyoxometalate solutions in nitromethane for a brief time — on the order of minutes. The geometry of these new devices is unique as the functions of hole and electron collection are built into the light-absorbing active layer, resulting in the simplest single-layer geometry with few interfaces.
“High-performing organic solar cells require a multiple layer device structure,” said co-author Thuc-Quyen Nguyen, a professor in UCSB’s Department of Chemistry and Biochemistry. “The realization of single-layer photovoltaics with our approach will simplify the device fabrication process and therefore should reduce the cost. The initial lifetime testing of these single layer devices is promising. This exciting development will help transform organic photovoltaics into a commercial technology.”
Organic solar cells are unique within the context of providing transparent, flexible and easy-to-fabricate energy-producing devices. These could result in a host of novel applications, such as energy-harvesting windows and films that enable zero-cost farming by creating greenhouses that support crops and produce energy at the same time.
Learn more: Solar Cell Game Changer
Nanyang Technological University, Singapore (NTU Singapore) has developed a new material that will make vehicles and buildings cooler and quieter compared to current insulation materials in the market.
Known as aerogel composites, this new foam insulates against heat 2.6 times better than conventional insulation foam.
When compared to traditional materials used in soundproofing, it can block out 80 per cent of outside noise, 30 per cent more than the usual ones.
Made from silica aerogels with a few other additives, this new material is now ready for commercialisation and is expected to hit the market early next year. The promising product has the potential to be used in a wide range of applications, including in building and construction, oil and gas and the automotive industry.
The aerogel composites took NTU Assoc Prof Sunil Chandrankant Joshi and his then-PhD student, Dr Mahesh Sachithanadam, four years to develop. The technology had been published in peer-reviewed scientific journals and a patent has been filed by NTU’s innovation and enterprise arm NTUitive.
A local company, Bronx Creative & Design Center Pte Ltd (BDC), has licensed this aerogel composites technology with a joint venture of S$7 million (USD$5.2 million), and a production plant that will be operational by 2017.
It will produce the aerogel composites in various forms such as sheets or panels, in line with current industry sizes.
Assoc Prof Sunil said the foam will be easy to install and use as it is thinner than conventional foam yet has better performance.
“Our NTU thin foam is also greener to manufacture, as it does not require high heat treatment or toxic materials in its production. It is therefore a lot more eco-friendly and less hazardous to the environment,” explained Prof Sunil who is from NTU’s School of Mechanical and Aerospace Engineering.
Mr Thomas Ng, R&D Director of BDC, said this new material could address a real market need for high-performance heat insulation and better sound proofing.
“With the global industries moving towards green manufacturing and a lowered carbon footprint, the new foam we produce will help address their needs and yet give a better performance,” Mr Ng said.
“Moving forward, we hope to show the current market that going green doesn’t mean that performance has to be compromised. We will be working with industry partners and certified testing labs to achieve the relevant standards and certifications.
“BDC has plans to have a footprint locally as we are now in talks with a few local parties to make this happen, in line with Singapore’s vision of being a global leader in the Advanced Manufacturing and Engineering sector,” he added.
BDC has various negotiations underway with other companies to expand the production to India and various Southeast Asia countries within the next three years.
High Performance Foam
The new aerogel composite has been branded “Bronx AeroSil” by BDC and is being developed for various applications by Dr Mahesh, now the Chief Technology Officer at BDC.
For example, to reduce the noise generated by a truck driving by to that of a normal conversation, only 15mm of the new material would be needed. On the other hand, common insulation foam requires a thickness of 25mm.
The aerogel composite can reduce noise by as much as 80 per cent whereas normal foam only reduces sound by 50 per cent, explained Dr Mahesh.
Against heat, Bronx AeroSil which is 50 per cent thinner than conventional foam will still out-perform it by 37 per cent.
“For both heat insulation and sound-proofing, we can now use less material to achieve the same effect, which will also lower the overall material and logistic costs,” Dr Mahesh said.
Apart from being a good thermal and acoustic insulator, it is also non-flammable – a crucial factor for materials used in high heat environments common in the oil and gas industries.
It is also resilient and can withstand high compression or heavy loads. A small 10cm by 10cm piece of the aerogel composite material weighing just 15 grams can take up to 300 kilogrammes of weight, maintaining its shape without being flattened.
In the first quarter of next year, BDC will begin mass producing the aerogel composites for their clients, which include companies from the automotive, electronics, and oil and gas sectors.
Further research and optimisation would be carried out to improve the performance of the aerogel composite material to ensure it maintains its competitiveness edge against other technologies, said Dr Mahesh.
A trio of Clemson University scientists has unveiled a groundbreaking computational software called “GFlow” that makes wildlife habitat connectivity modeling vastly faster, more efficient and superior in quality and scope.
After eight years of research and development, the revolutionary software was announced in the scientific journal Methods in Ecology and Evolution. Clemson University postdoctoral fellow Paul Leonard is the lead author of the article, “GFlow: software for modeling circuit theory-based connectivity at any scale.” Clemson’s co-authors are Rob Baldwin, the Margaret H. Lloyd-Smart State Endowed Chair in the forestry and environmental conservation department; and Edward Duffy, formerly a computational scientist in the cyberinfrastructure technology integration department who recently left the university to join BMW.
“Historically, landscape connectivity mapping has been limited in either extent or spatial resolution, largely because of the amount of time it took computers to solve the enormous equations necessary to create these models. Even using a supercomputer, it could take days, weeks or months,” said Leonard, who is in the forestry and environmental conservation department along with Baldwin. “But GFlow is more than 170 times faster than any previously existing software, removing limitations in resolution and scale and providing users with a level of quality that will be far more effective in presenting the complexities of landscape networks.”
Habitat connectivity maps are paired with satellite imagery to display the potential corridors used by animal populations to move between both large and small areas. Billions of bytes of data – including fine-grain satellite photographs and on-the-ground research – produce geospatial models of the movements of everything from black bears to white salamanders. These models help federal and state governments, non-governmental organizations and individual landowners redefine their conservation priorities by computationally illustrating the passageways that will need to be preserved and enhanced for animals to be able to continue to intermingle.
“The take-home from this is that you can quickly compute very complicated scenarios to show decision-makers the impacts of various outcomes,” said Baldwin, whose conservation career has spanned decades throughout the United States and Canada. “You want to put a road here? Here’s what happens to the map. You want to put the road over there? We’ll recalculate it and show you how the map changes. GFlow is dynamic, versatile and powerful. It’s a game-changer in a variety of ways.”
When Leonard began his initial work under Baldwin’s tutorship, the existing software used for habitat connectivity mapping was slow, inefficient and consumed enormous amounts of computer memory. Leonard soon realized he would need the expertise of a computational scientist to overcome these frustrating limitations. Thus, his collaboration with Duffy began – and both ended up spending countless hours in front of their computer screens, synthesizing Leonard’s ecological know-how with Duffy’s cyber skills. The end result? A large-scale map that once would have taken more than a year to generate now takes just a few days.
“Until GFlow, the software available for ecologists was poorly conceived in terms of speed and memory usage,” said Duffy, who was the lead developer of the new software. “So I rewrote the code from scratch and reduced individual calculations from about 30 minutes to three seconds. And I also significantly reduced the amount of memory generated by the program. In the old code, one project we worked on took up 90 gigabytes of memory. With GFlow, only about 20 gigabytes would be needed. It’s most efficient when used in conjunction with a supercomputer, but it even works in a more limited capacity on desktop computers.”
GFlow will enable scientists to solve ecological problems that span large landscapes. But in addition to helping animals survive and thrive, GFlow can also be used for human health and well-being. For instance, GFlow has the capacity to monitor the spread of the Zika virus by documenting the location of each new case and then predicting its potential spread to previously uninfected areas.
“This software can monitor the flow of any natural phenomenon across space where there is heterogeneous movement that is based on some resistance to this movement,” Leonard said. “Besides Zika, there are other health and disease patterns that can be modeled using GFlow. And also other natural phenomena, such as the spread of wildfire in the southeastern United States and other areas around the country. We can parameterize wind strength and shifts, how much fuel is on the ground and calculate the spread across really large areas. So we’re examining all these possibilities and are open to collaboration with other domain experts who might be interested in using GFlow.”
Additional contributors to Friday’s journal article were Brad McRae, a senior landscape ecologist for The Nature Conservancy; and Viral Shah and Tanmay Mohapatra of Julia Computing, a privately held company. Ron Sutherland and the Wildlands Network provided valuable data that was used extensively during the development of GFlow
“Collaboration has played a huge role in this,” Baldwin said. “We’ve worked across departments. We’ve worked across boundaries. And without Clemson’s investment in the Palmetto Cluster supercomputer, none of this would have been possible. This collaboration has improved spatial modeling for ecological processes in time and space. And because it’s so computationally efficient, it can be done for extremely large areas – regions, nations, continents or possibly even the entire planet – in unprecedented detail.”