Exotic Material Shows Promise as Flexible, Transparent Electrode

Engineerblogger
March 8, 2012

An array of microcircuits made of a 10-nanometer-thick film of bismuth sulfide, an exotic material called a topological insulator, on an insulating mica substrate can be flexed without damaging its electrical properties.

Photo by Hailin Peng, Peking University.

An international team of scientists with roots at SLAC and Stanford has shown that ultra-thin sheets of an exotic material remain transparent and highly conductive even after being deeply flexed 1,000 times and folded and creased like a piece of paper.

The result could open this class of unusual materials, called topological insulators, to its first practical applications: flexible, transparent electrodes for solar cells, sensors and optical communications devices.

“It’s rare for a good conductor to be both transparent and durable as well,” said Zhi-Xun Shen of SLAC and Stanford’s Institute for Materials and Energy Sciences (SIMES).

Researchers led by Shen, Zhongfan Liu and Hailin Peng of Peking University in China, and Yulin Chen of Oxford University in England published their results last week in Nature Chemistry. Until recently, Peng and Chen were graduate students and postdoctoral researchers at Stanford and SIMES. They have continued to collaborate with Shen’s research team after being named professors at their current universities.

The researchers made and tested samples of a compound in which sheets of bismuth and selenium, each just one atom thick, alternate to form five-layer units. The bonds between the units are weak, allowing the overall material to flex while retaining its durability. And as a topological insulator – a new state of quantum matter – the material conducts electricity only on its surface while its interior remains insulating, an unexpected property with unknown potential for fundamental research and practical applications.

Since surface atoms dominate the structure of bismuth selenide, it is an exceptionally good electrical conductor – as good as gold. Unlike gold, however, bismuth selenide is transparent to infrared light, which we know as heat. While about half the solar energy that hits the Earth comes in the form of infrared light, few of today’s solar cells are able to collect it. The transparent electrodes on the surfaces of most cells are either too fragile or not transparent or conducting enough. The new material could get around that problem and allow cells to harvest more of the sun’s spectrum of wavelengths.

The researchers’ experiments also showed that bismuth selenide does not degrade significantly in humid environments or when exposed to oxygen treatments that are common in manufacturing.

“In addition to being a scientific success,” Chen said, “this demonstration should alert engineers and companies that topological insulators can also be important commercially.”

Peng added, “Infrared light pulses carry phone calls and data through optical fiber networks, so bismuth selenide may be useful in communications devices. This material could also improve infrared sensors common in scientific equipment and aerospace systems.”

Peng and colleagues made the bismuth selenide samples and conducted the flexing, conductivity and transparency tests in China. The researchers confirmed that the samples were topological insulators at the Stanford Synchrotron Radiation Lightsource’s Beam Line 5-4 at SLAC.

Theorists first proposed topological insulators in 2004, and experimentalists made the first examples, using mercury telluride at very low temperatures, two years later. Guided by theory, Chen, Shen and colleagues proved in 2009 that cheaper, more abundant and easier-to-handle bismuth telluride and similar compounds containing antimony and selenium are topological insulators at room temperature. Also in 2009, Peng, Shen and colleagues discovered important electrical conduction behavior in bismuth selenide nanoribbons.





Source:  SLAC National Accelerator Laboratory

The Future of Nuclear Energy

Engineerblogger
March 7, 2012

Aerial photograph of Vogtle nuclear power plant site, just outside Augusta, Georgia. The existing Vogtle 1 adn 2 operating units to the left and the Vogtle 3 and 4 construction site to the right. Courtesy: Southern Company 2011

Last March, the world watched closely as Japan struggled to contain a series of equipment failures, hydrogen explosions and releases of radioactive materials at the Fukushima Daiichi Nuclear Power Plant.

The historic tsunami following the 9.0-magnitude earthquake destroyed the reactors’ connection to the power grid, causing them to overheat. Hundreds of people were exposed to increased levels of radiation. Thousands more were evacuated. Although Japanese officials have since declared the plant stable, the cleanup will be expensive and is expected to take decades.

A year later, however, the United States is moving forward with nuclear power. For the first time since 1978, the National Regulatory Commission has approved two new plants. The $14 billion facilities will be built just outside Augusta and operated by Atlanta-based Southern Company. They’re scheduled to be up and running by 2016 and 2017 and should produce about 10 percent of Georgia’s power.

“It’s smart to continue generating nuclear power in the United States,” said Marilyn Brown, professor in Georgia Tech’s School of Public Policy. “It is a reliable, cost-competitive option that doesn’t contribute to air pollution or contribute to greenhouse gas emissions.” Brown helps shape the nation’s energy policies as a board member of the Tennessee Valley Authority (TVA) and chair of the company’s Nuclear Oversight Committee.

Brown said that nuclear power plants are expensive to build, compared to natural gas facilities.

“But they are clearly worth the investment,” she said. “A nuclear plant produces no carbon dioxide emissions and four times the power of a typical natural gas facility. Fourteen billion is a big number, but the plants should stay online for 50 to 70 years.”

Despite the benefits, critics will always point to the risk of a nuclear catastrophe. These are the nation’s first approved nuclear facilities since Pennsylvania’s Three Mile Island accident in 1979. Experts contend that modern plant designs are much safer than those built previously.

“The new plant designs are passively safe, so there are far fewer issues to worry about, like those that occurred with the older plants at Fukushima with the loss of off-site power,” said Glenn Sjoden, Georgia Tech professor of nuclear and radiological engineering. “With the new plants, you have a convection cooling loop that uses gravity and runs by itself for days in the event of lost power. There would be no active pumping required. . . . The more modern designs and precautions taken make nuclear the best option to satisfy our energy needs.”

Since last year’s incident, the Nuclear Regulatory Commission has been reviewing existing U.S. plants to ensure that they can withstand earthquakes, floods and other natural disasters and making retrofit upgrades when necessary, Sjoden said.

Critics point to nuclear waste as another challenge with nuclear power. Each of the nation’s 104 plants store the radioactive waste on-site in steel casks protected by concrete and other safety systems. These are safe too, Brown said, because of careful construction and maintenance.

Nuclear waste would be a nonissue if the U.S. reprocessed its spent fuel like other nations such as France, Sjoden said.

“Like most nations, they recycle their used fuel, since 95 percent of the fuel can be recycled back into the reactor and used again, making nuclear power the most ‘green’ energy source out there,” Sjoden said. “Burying the waste, as we do in the United States, is completely wasteful.”

The United States generates almost 20 percent of its energy from nuclear plants, the same amount as natural gas. Coal supplies 50 percent. The remainder is generated from hydropower and other natural sources.

“We must develop more renewables sources, such as wind, solar and biopower,” says Brown. “Industry leaders, business and the general public must also become more energy efficient. That is the key to our future.”

Source:  Georgia Institute of Technology

Graphene Battery Turns Ambient Heat Into Electric Current

Engineerblogger
March 7, 2012

Credit: Technology Review

Here's an interesting idea for a battery. The thermal velocity of ions in aqueous solution is huge--hundreds of metres per second at room temperature. And yet few people have studied this process or its potential to generate current.

Step forward Zihan Xu at The Hong Kong Polytechnic University and a few buddies who have not only studied this process but seemingly mastered it too.

These guys have created a circuit consisting of an LED connected to a strip of graphene by some wire. They simply placed the graphene in a solution of copper chloride and watched. Sure enough, the LED lights up. (Actually, they needed six of these graphene circuits in series to generate the 2V needed to make the LED light up but you get the picture.)

Here's what's going on, according to Zihan and co. The copper ions, which have a double positive charge, move through the solution at a rate of about 300 metres per second thanks to the thermal energy of the solution at room temperature.

When an ion smashes into the graphene strip, the collision generates enough energy to kick a delocalised electron out of the graphene.

The electron then has two options: it can either leave the graphene strip and combine with the copper ion or it can travel through the graphene strip and into the circuit.

It turns out that the mobility of electrons is much higher in graphene than it is through the solution, so the electron naturally chooses the route through the circuit. It is this that lights up the LED.

"The released electrons prefer to travel across the graphene surface...instead of going into the electrolyte solution. That is how the voltage was produced by our device," say Zihan and co.

So the energy generated by this device comes from ambient heat. These guys say there were able to increase the current by heating the solution and also by accelerating the copper ions with ultrasound. They even claim to have kept their graphene battery running for 20 days on nothing but ambient heat.

But there's an important question mark. One alternative hypothesis is that some kind of chemical reaction is generating the current, just as in an ordinary battery.

However, Zihan and co say they ruled this out with a couple of control experiments. However, these are described in some supplementary material that they do not appear to have put on the arXiv. They'll need to make this available before others will take the claim seriously, of course.

Taken at face value, however, this looks to be a hugely important result. Others have generated current in graphene simply by passing moving water over it, so it's not really a surprise that moving ions can do the job as well.

It raises the prospect of clean, green batteries powered by nothing but ambient heat. As Zihan and co modestly put it: "it represents a huge breakthrough for the research of self-powered technology".

Let's hope they're right. But for the moment at least, the jury must remain undecided.

Source: Technology Review

Additional Information:

•  To read the abstract"Self-Charged Graphene Battery Harvests Electricity from Thermal Energy of the Environment" in the Cornell University Library.

Nanotrees harvest the sun's energy to turn water into hydrogen fuel

Engineerblogger
March 7, 2012

Schematic shows the light trapping effect in nanowire arrays. Photons on are bounced between single nanowires and eventually absorbed by them (R). By harvesting more sun light using the vertical nanotree structure, Wang’s team has developed a way to produce more hydrogen fuel efficiently compared to planar counterparts (L) where light is simply reflected off the surface. Image Credit: Wang Research Group, UC San Diego Jacobs School of Engineering.

University of California, San Diego electrical engineers are building a forest of tiny nanowire trees in order to cleanly capture solar energy without using fossil fuels and harvest it for hydrogen fuel generation. Reporting in the journal Nanoscale, the team said nanowires, which are made from abundant natural materials like silicon and zinc oxide, also offer a cheap way to deliver hydrogen fuel on a mass scale.

“This is a clean way to generate clean fuel,” said Deli Wang, professor in the Department of Electrical and Computer Engineering at the UC San Diego Jacobs School of Engineering.

The trees’ vertical structure and branches are keys to capturing the maximum amount of solar energy, according to Wang. That’s because the vertical structure of trees grabs and adsorbs light while flat surfaces simply reflect it, Wang said, adding that it is also similar to retinal photoreceptor cells in the human eye. In images of Earth from space, light reflects off of flat surfaces such as the ocean or deserts, while forests appear darker.

Wang’s team has mimicked this structure in their “3D branched nanowire array” which uses a process called photoelectrochemical water-splitting to produce hydrogen gas. Water splitting refers to the process of separating water into oxygen and hydrogen in order to extract hydrogen gas to be used as fuel. This process uses clean energy with no green-house gas byproduct. By comparison, the current conventional way of producing hydrogen relies on electricity from fossil fuels

“Hydrogen is considered to be clean fuel compared to fossil fuel because there is no carbon emission, but the hydrogen currently used is not generated cleanly,” said Ke Sun, a PhD student in electrical engineering who led the project.

By harvesting more sun light using the vertical nanotree structure, Wang’s team has developed a way to produce more hydrogen fuel efficiently compared to planar counterparts. Wang is also affiliated with the California Institute of Telecommunications and Information Technology and the Material Science and Engineering Program at UC San Diego.

The vertical branch structure also maximizes hydrogen gas output, said Sun. For example, on the flat wide surface of a pot of boiling water, bubbles must become large to come to the surface. In the nanotree structure, very small gas bubbles of hydrogen can be extracted much faster. “Moreover, with this structure, we have enhanced, by at least 400,000 times, the surface area for chemical reactions,” said Sun.

In the long run, what Wang’s team is aiming for is even bigger: artificial photosynthesis. In photosynthesis, as plants absorb sunlight they also collect carbon dioxide (CO2) and water from the atmosphere to create carbohydrates to fuel their own growth. Wang’s team hopes to mimic this process to also capture CO2 from the atmosphere, reducing carbon emissions, and convert it into hydrocarbon fuel.

In this experiment, nanotree electrodes are submersed in water and illuminated by simulated sun light to measure electricity output of the device. Photo Credit: Joshua Knoff, UC San Diego Jacobs School of Engineering.

“We are trying to mimic what the plant does to convert sunlight to energy,” said Sun. “We are hoping in the near future our ‘nanotree’ structure can eventually be part of an efficient device that functions like a real tree for photosynthesis."

The team is also studying alternatives to zinc oxide, which absorbs the sun’s ultraviolet light, but has stability issues that affect the lifetime usage of the nanotree structure.

Source: University of California, San Diego

Researchers Discover New Method of Making Nanoparticles

Engineerblogger
March 6, 2012

Keith Roper, University of Arkansas

An engineering researcher at the University of Arkansas and his colleagues at the University of Utah have discovered a new method of making nanoparticles and nanofilms to be used in developing better electronic devices, biosensors and certain types of high-powered and highly specific microscopes used for scientific research.

The never-ending quest to build faster, more efficient and more reliable electronic devices starts deep down below the molecular level, where nanoparticles – far too small for the human eye to detect – make up the building blocks of the latest processing hardware. In pursuit of this goal, scientists and engineers are constantly investigating new materials and better methods of developing or assembling these materials.

The researchers’ nanoparticles, made of gold and deposited onto silicon substrates by a unique chemical process, are nontoxic and inexpensive to make and have superior dimensions, densities and distribution when compared to other nanoparticles and conventional methods of producing nanoparticles. The unique deposition technique has the further advantage of being able to rapidly coat fragile, three-dimensional and internal surfaces at the temperature and pressure of its surroundings without requiring conductive substrates or expensive, sophisticated equipment.

“Using successive thermal treatments, we characterized optical and structural features of an inexpensive, molecule-to-molecule, bottoms-up approach to create thermally stable, gold-nanoparticle ensembles on silica,” said Keith Roper, associate professor of chemical engineering at the University of Arkansas. “Images and analysis from scanning electron microscopy and atomic force microscopy revealed that particle densities are the highest reported to date. Our method also allows faster preparation than self-assembly or lithography and allows directed assembly of nanoparticle ensembles on 3D surfaces.”

The researchers’ unique approach improves upon a method that involves depositing atoms from a solution onto a substrate with a tin-sensitized surface. The researchers use a novel continuous-deposition process and then heat these deposited atoms to transform “islands” of nanoparticle material into desired forms. The resulting spherical nanoparticles can have diameters between 5 and about 300 nanometers. A nanometer is a billionth of a meter. A human hair typically has a diameter of 70,000 nanometers.

Roper said that microscopic images and spectroscopic data suggest that ultrathin films prepared by their new approach are smoother than conventional “sputtered” or evaporated gold films and may exhibit better optical features, such as reduced surface-roughness scattering. These features are desirable in devices such as photovoltaic cells in which narrow metal layers significantly affect local electromagnetic fields. Smoother thin films also could improve the limits of detection, sensitivity and photocurrent, respectively, in such applications.

The researchers’ recent studies in this area have been published in Langmuir and Journal of Physical Chemistry C, journals of the American Chemical Society. The researchers were awarded U.S. Patent No. 8,097,295 on Jan. 17 for the development.

Roper is holder of the Charles W. Oxford Professorship of Emerging Technologies. He is also assistant director of the graduate program in microelectronics/photonics.

Source:  University of Arkansas

Developing Robots That Can Teach Humans

Engineerblogger
March 6, 2012

A few years ago, AnthroTronix, Inc., an engineering research and development firm in College Park, Md., introduced Cosmobot, a type of social robot for therapists and educators who work with developmentally and learning disabled children, including those with autism and cerebral palsy. By imitating human joint movement in its shoulders, arms, hands and head, Cosmobot motivates children to develop new skills more quickly than is typical with traditional therapy. But why does this work? Why do children respond so favorably to educational programs taught by technology? And, when the technology is a robot made from inanimate materials, how do children learn to distinguish between the robot and a living thing? Credit: NSF

Researchers are programming robot teachers to gaze and gesture like humans

When it comes to communication, sometimes it's our body language that says the most--especially when it comes to our eyes.

"It turns out that gaze tells us all sorts of things about attention, about mental states, about roles in conversations," says Bilge Mutlu, a computer scientist at the University of Wisconsin-Madison.

Mutlu knows a thing or two about the psychology of body language. He bills himself as a human-computer interaction specialist. Support from the National Science Foundation (NSF) is helping Mutlu and his fellow computer scientist, Michael Gleicher, take gaze behavior in humans and create algorithms to reproduce it in robots and animated characters.

"These are behaviors that can be modeled and then designed into robots so that they (the behaviors) can be used on demand by a robot whenever it needs to refer to something and make sure that people understand what it's referring to," explains Mutlu.

Both Mutlu and Gleicher are betting that there will be significant benefits to making robots and animated characters "look" more like humans. "We can build animated agents and robots that can communicate more effectively by using the very subtle cues that people use," says Gleicher.

Mutlu sets up experiments to study the effect of a robot gaze on humans. "We are interested in seeing how referential gaze cues might facilitate collaborative work such that if a robot is giving instructions to people about a task that needs to be completed, how does that gaze facilitate that instruction task and people's understanding of the instruction and the execution of that task," says Mutlu.

To demonstrate, a three-foot-tall, yellow robot in the computer sciences lab greets subjects, saying: "Hi, I'm Wakamaru, nice to meet you. I have a task for you to categorize these objects on the table into boxes."

In one case, the robot very naturally glances toward the objects it "wants" sorted as it speaks. In another case, the robot just stares at the person. Mutlu says the results are pretty clear. "When the robot uses humanlike gaze cues, people are much faster in locating the objects that they have to move."

Another experiment run by Mutlu and Gleicher's team explores how an animated character's eyes affect human learning. A character projected on a screen says to the viewer, "Today, I'll be telling you a story that comes straight from ancient China." Behind the animated character is a map of China that he'll be referring to in the lecture that runs several minutes.

"The goal of the experiment is to see if we could achieve a high-level outcome, like learning, by controlling an animated character's gaze," says Gleicher. "What we found was when the lecturer looked at the map at appropriate times to indicate to the participant that now I'm talking about something on the map, the participant ended up learning more about spatial locations."

The team hopes their work will transform how humanoid robots and animated characters interface with people, especially in classrooms. "We can design technology that really benefits people in learning, in health and in well-being, and in collaborative work," notes Mutlu.

Now, that's technology worth keeping an eye on!




Source:  National Science Foundation (NSF)

Energy Squeeze: Squeezing polymers produces chemical energy

Engineerblogger
March 5, 2012

Bartosz A. Grzybowski

A polymer is a mesh of chains, which slowly break over time due to the pressure from ordinary wear and tear. When a polymer is squeezed, the pressure breaks chemical bonds and produces free radicals: ions with unpaired electrons, full of untapped energy. These molecules are responsible for aging, DNA damage and cancer in the human body.

In a new study, Northwestern University scientists turned to squeezed polymers and free radicals in a search for new energy sources. They found incredible promise but also some real problems. Their report is published by the journal Angewandte Chemie.

The researchers demonstrated that radicals from compressed polymers generate significant amounts of energy that can be used to power chemical reactions in water. This energy has typically been unused but now can be harnessed when polymers are under stress in ordinary circumstances -- as in shoe soles, car tires or when compacting plastic bags.

They also discovered during the study that a silicone polymer commonly used in implants for cosmetic procedures releases a large quantity of harmful free radicals when the polymer is under only a moderate amount of pressure. These findings suggest the safety of certain polymer-based medical implants should be looked at more closely.

“We have established that polymers under stress create free radicals with overall efficiencies of up to 30 percent and shoot the radicals out into the surrounding medium where they can drive chemical reactions,” said Bartosz A. Grzybowski, an author of the paper and the Kenneth Burgess Professor of Physical Chemistry and Chemical Systems Engineering. “These radicals can be useful or they can be harmful, depending on the situation.”

Grzybowski and his team are the first to use this energy to drive chemical reactions by simply surrounding the compressed polymer with water containing desired reagents.

The radicals created in the polymer migrate toward the polymer/water interface where they produce hydrogen peroxide, which then can drive chemical processes.

“You can get a surprisingly large amount of chemical energy from a polymer under compression,” Grzybowski said. “This energy is, in a sense, free for the taking. Under normal circumstances, the energy is virtually never retrieved from deformed polymers, which then age unproductively. But you could recharge a battery from the energy produced by walking or driving a car. And you could capture even more energy when compacting millions of plastic bags.”

Grzybowski is also director of Northwestern’s Non-Equilibrium Energy Research Center, which is funded by the U.S. Department of Energy.

“We are interested in new sources of chemical energy, and this energy from the simple breaking of polymers’ bonds is not being used,” he said. “By surrounding the polymer with a medium, such as water, we can produce environmentally friendly chemical energy. One direction we are pursuing is to use this energy to sanitize water in developing countries. This is possible because hydrogen peroxide produced by squeezed polymers kills bacteria.”

The researchers confirmed that mechanical deformation -- moderate squeezing -- created free radicals in the polymers. They also determined the number of radicals produced in a polymer under pressure is approximately 1016 (10 to the 16th) radicals per cubic centimeter of polymer -- a substantial amount.

They next filled polymer tubes with water, squeezed the tubes and measured the total number of radicals that migrated into the surrounding solution. They found that nearly 80 percent of the radicals made the trip.

Grzybowski and his team demonstrated they can squeeze a polymer, such as what might be found in a shoe, tire or plastic bag, and get a mechanical-to-chemical energy conversion of up to 30 percent -- approaching the energy efficiency of a car engine.

The hydrogen peroxide produced when a polymer surrounded by water is squeezed can power a variety of chemical reactions, including fluorescence, nanoparticle synthesis and dye bleaching, the researchers showed.

To illustrate the process, they converted a Nike Air LeBron shoe into a “lightning shoe,” where the air pockets in the polymeric sole are filled with a solution of a compound that lights up in the presence of radicals. After a person walked in the shoe for 30 minutes or more, enough radicals were created to generate a blue glow visible to the naked eye.

The researchers studied seven different polymers, including a number of particular public interest. Poly(dimethylsiloxane), a silicon-based material commonly used in medical implants, was one of them. In the lab experiments, the medium surrounding the polymer and the amount of pressure exerted on the material were similar to what would be found in the human body, Grzybowski pointed out.

“Our findings are somewhat worrisome since every polymeric implant in the human body experiences mechanical stresses and, as we now know, can produce harmful free radicals and liberate them into surrounding tissues, which may contribute to diseases such as cancer, stroke, myocardial infarction, diabetes and other major disorders,” Grzybowski said. “With this knowledge, I am quite happy to have a metal implant in my knee, rather than a polymer implant.

“From a scientific perspective, our work proves yet again that a phenomenon can be useful or harmful depending on how we implement it,” he said. “The same polymer can be a useful source of energy when outside of a human body, yet a potential risk hazard when implanted into it.”

The U.S. Department of Energy funded the research.

Source: Northwestern University

Additional Information:

• The title of the paper is “Mechanoradicals Created in ‘Polymeric Sponges’ Drive Reactions in Aqueous Media.” In addition to Grzybowski, other authors of the paper are H. Tarik Baytekin and Bilge Baytekin.
  

Heart-powered pacemaker could one day eliminate battery-replacement surgery

Engineerblogger
March 5, 2012

An artificial pacemaker from St. Jude Medical, with electrode.

A new power scheme for cardiac pacemakers turns to an unlikely source: vibrations from heartbeats themselves.

Engineering researchers at the University of Michigan designed a device that harvests energy from the reverberation of heartbeats through the chest and converts it to electricity to run a pacemaker or an implanted defibrillator. These mini-medical machines send electrical signals to the heart to keep it beating in a healthy rhythm. By taking the place of the batteries that power them today, the new energy harvester could save patients from repeated surgeries. That's the only way today to replace the batteries, which last five to 10 years.

"The idea is to use ambient vibrations that are typically wasted and convert them to electrical energy," said Amin Karami, a research fellow in the U-M Department of Aerospace Engineering. "If you put your hand on top of your heart, you can feel these vibrations all over your torso."

The researchers haven't built a prototype yet, but they've made detailed blueprints and run simulations demonstrating that the concept would work. Here's how: A hundredth-of-an-inch thin slice of a special "piezoelectric" ceramic material would essentially catch heartbeat vibrations and briefly expand in response. Piezoelectric materials' claim to fame is that they can convert mechanical stress (which causes them to expand) into an electric voltage.

Karami and his colleague Daniel Inman, chair of Aerospace Engineering at U-M, have precisely engineered the ceramic layer to a shape that can harvest vibrations across a broad range of frequencies. They also incorporated magnets, whose additional force field can drastically boost the electric signal that results from the vibrations.

The new device could generate 10 microwatts of power, which is about eight times the amount a pacemaker needs to operate, Karami said. It always generates more energy than the pacemaker requires, and it performs at heart rates from 7 to 700 beats per minute. That's well below and above the normal range.

Karami and Inman originally designed the harvester for light unmanned airplanes, where it could generate power from wing vibrations.

A paper on the research, titled "Powering pacemakers from heartbeat vibrations using linear and nonlinear energy harvesters," is published in the current print edition of Applied Physics Letters.

The research is funded by the National Institute of Standards and Technology and the Institute for Critical Technology and Applied Science at Virginia Tech.

Source: University of Michigan

Graphene-Based Optical Modulators Poised to Break Speed Limits in Digital Communications

Engineerblogger
March 2, 2012

In yet another astounding application of the “wonder material” graphene, scientists at the University of California, Berkeley discovered that it makes an excellent active media for optical modulators. Graphene-based modulators are expected to significantly enhance ultrafast optical communication and computing. The team will report on their findings at the Optical Fiber Communication Conference and Exhibition/National Fiber Optic Engineers Conference (OFC/NFOEC) taking place next week in Los Angeles.

Modulators play a vital role in communications due to their switching ability, because this is what controls the speed that data packets can travel through networks. As the speed of data pulses sent out increases, it means that greater volumes of information can be transmitted.

“We demonstrated a graphene-based optical modulator with a broad optical bandwidth (1.35-1.6 µm), a small device footprint (25 µm2), and high operational speed (1.2 GHz at 3dB) under ambient conditions—all of which are essential for optical interconnects for future integrated optoelectronic systems,” says Ming Liu, a post-doctoral researcher working at UC Berkeley’s NSF Nanoscale Science and Engineering Center. “The modulation efficiency of a single layer of a hexagonal carbon atom is already comparable to, if not better than, traditional semiconductor materials, which are orders of magnitude larger in active volume.”

Looking into future applications, graphene-based modulators could be very compact and potentially perform at speeds up to 10 times faster than today’s technology allows. They may someday enable consumers to stream full-length, high-definition, 3-D movies onto their smartphones within mere seconds.

Liu’s talk, “Graphene-based optical modulators,” takes place Tuesday, March 6 at 3:30 p.m. in the Los Angeles Convention Center.

About OFC/NFOEC

For more than 35 years, the Optical Fiber Communication Conference and Exposition/ National Fiber Optic Engineers Conference (OFC/NFOEC) has been the premier destination for converging breakthrough research and innovation in telecommunications, optical networking and, recently, datacom and computing. Uniting service providers, systems companies, enterprise customers, IT businesses and component manufacturers, along with researchers, engineers and development teams, OFC/NFOEC combines dynamic business programming, an exposition of more than 500 companies and cutting-edge peer-reviewed research into one event that showcases the trends and pulse of the entire optical communications industry. OFC/NFOEC is managed by the Optical Society (OSA) and co-sponsored by OSA, the Institute of Electrical and Electronics Engineers/Communications Society (IEEE/ComSoc) and the IEEE Photonics Society. Acting as a non-financial technical co-sponsor is Telcordia Technologies

Source:  Optical Society of America (OSA)

Job Posting: Oregon State University

OSU is hiring an Assistant Ombuds for its new Ombuds program. This is a full-time, 12-month, fixed term professional faculty position that reports to University Ombudsman, Sue Theiss. The Assistant Ombuds is responsible for communication and marketing; coordination of programming and training; administrative support and office management; and assistant-level Ombuds services. 

Applicants must have a bachelor's degree in a related field or combination of education and experience, and one to three years comparable professional experience (including knowledge of conflict resolution and mediation techniques and principles, and the role of the Ombuds, and experience working in higher education). Applications are due March 31, 2012. No salary indicated. (OSU Jobs.)

Related posts: Oregon State University Will Create an Ombuds Program; Guide to Oregon Ombuds Programs; Job Posting; University of Arkansas Ombuds Posts 2010-11 Annual Report; Oregon State University Names First Ombuds.

Exotic Material Boosts Electromagnetism Safely

Engineerblogger
March 1, 2012

Yaroslav Urzhumov

By using exotic man-made materials, scientists from Duke University and Boston College believe they can greatly enhance the forces of electromagnetism (EM), one of the four fundamental forces of nature, without harming living beings or damaging electrical equipment.


This theoretical finding could have broad implications for such applications as magnetic levitation trains, which ride inches above the surface without touching it and are propelled by magnets receiving electrical current.

As the term indicates, EM is made up of two types of fields – electric and magnetic. Alternating current sources generate both electric and magnetic fields, and increasing one of them generally leads to the increase in the other. Electrical fields can cause problems if they get too high.

“For any EM applications dealing with things on the human scale, high-intensity EM fields needed for the generation of strong EM forces interfere with other devices and may be harmful to biological tissues, including humans,” said Yaroslav Urzhumov, assistant research professor in electrical and computer engineering at Duke’s Pratt School of Engineering.

“The severity of this problem is substantially reduced if the fields are predominantly magnetic, since virtually all biological substances and the majority of conventional materials are transparent to magnetic fields,” Urzhumov said. “While we can’t suppress the electric field completely, a magnetically-active metamaterial could theoretically reduce the amount of current needed to generate a high enough magnetic field, thus reducing parasitic electric fields in the environment and making high-power EM systems safer. ”

The results of Urzhumov’s analysis were published online in the journal Physical Review B, and the team’s research was supported by the Air Force Office of Scientific Research.

The solution to this problem comes from the recent ability to fabricate exotic composite materials known as metamaterials, which are not so much a single substance, but an entire man-made structure that can be engineered to exhibit properties not readily found in nature. These metamaterials can be fabricated into a limitless array of sizes, shapes and properties depending on their intended use.

In the magnetic levitation train example, conventional electromagnets could be supplemented by a metamaterial, which would have been designed to produce significantly higher intensities of magnetic fields using the same amount of electricity.

The Duke scientists came up with the theoretical underpinning for the metamaterial, which is being fabricated by collaborators at Boston College, led by Willie Padilla, associate professor of physics.

“The metamaterial should be able to increase the magnetic force without increasing the electric current in the source coil,” Urzhumov said. “The phenomenon of magnetostatic surface resonance could allow magnetic levitation systems to increase the mass of objects being levitated by one order of magnitude while using the same amount of electricity.”

EM is currently being used in a host of devices and applications, ranging from subatomic “optical tweezers” scientists use to manipulate microscopic particles with laser beams, to potentially highly destructive weapons.

Urzhumov works in the laboratory of Duke’s David R. Smith, William Bevan Professor of electrical and computer engineering and director of Duke’s Center for Metamaterials and Integrated Plasmonics. Smith has previously demonstrated that similarly designed metamaterials could act as a “cloak” to different frequencies of light and other waves.

Wenchen Chen and Chris Bingham from Boston College’s physics department were also members of the research team.

Source: Duke University

Additional Infomation:

• The abstract "Magnetic levitation of metamaterial bodies enhanced with magnetostatic surface resonances" by Yaroslav Urzhumov, Wenchen Chen, Chris Bingham, Willie Padilla, and David R. Smith published in the journal Physical Review B, on Feb. 27, 2012

Seeking Cheaper, Nimbler Satellites and Safer Disposal of Space Debris

Engineerblogger
Feb 29, 2012

Credit: RPI

A new research program at Rensselaer Polytechnic Institute seeks to define the next-generation of low-orbit satellites that are more maneuverable, cheaper to launch, easier to hide, and longer lived. Additionally, this research holds the promise of guiding dead satellites and other space debris more safely to the Earth’s surface.

Led by Rensselaer faculty member Riccardo Bevilacqua, the research team is challenged with developing new theories for exploiting the forces of atmospheric drag to maneuver satellites in low-Earth orbits. Atmospheric drag is present up to 500 kilometers of altitude. Using this drag to alter the trajectory of a satellite alleviates the need to burn propellant to perform such action. Decreasing the amount of required propellant will make satellites weigh less, which reduces the overall cost of launching satellites into orbit.

Additionally, this new research holds the promise of using drag to control and maneuver dead satellites that are inoperable or have run out of propellant.

This project, titled “Propellant-free Spacecraft Relative Maneuvering via Atmospheric Differential Drag,” is funded by the Air Force Office of Scientific Research (AFOSR) Young Investigator Research Program with an expected three-year, $334,000 grant.

“Using differential drag to maneuver multi-spacecraft systems in low-Earth orbit is a new, non-chemical way to potentially reduce or even eliminate the need for propellant,” said Bevilacqua, assistant professor in the Department of Mechanical, Aerospace, and Nuclear Engineering (MANE) at Rensselaer. “Reducing the satellite’s overall mass at launch, by carrying less propellant, allows for easier, cheaper, and faster access to space. In addition, the ability to maneuver without expulsion of gases enables spacecraft missions that are harder to detect.”

Satellites experience drag while in low-Earth orbits, and this drag causes their orbits to decay—sending the satellites closer and closer to Earth. Bevilacqua wants to take advantage of this drag by attaching large retractable panels to satellites. When deployed, these panels would work like a parachute and create more drag in order to slow down or maneuver the satellite.

This type of system could be built into new satellites, or even designed as a separate device that could be attached to existing satellites already in orbit. The drag panel system would use electrical power—which can be recharged via solar panels—to perform its maneuvers. The system would not require any fuel or propellant. Bevilacqua said such a device could be attached to a dead satellite already in freefall, in order to help control where the satellite will land on the Earth’s surface.

This new project is a key component of Bevilacqua’s overall research portfolio, which focuses on the guidance, navigation, and control of multiple spacecraft. The overall trend in spacecraft design is to go smaller and smaller, he said. Today’s satellites are generally one big unit. In the future, satellite systems likely will be made up of many smaller satellites that join together and form one larger device. This type of modular system allows for individual components to be replaced or upgraded while the overall system remains functional in orbit. One of the major challenges to realizing this vision is developing a propellant-free means to maneuver small satellites so they’re able to rendezvous and join with one another. Differential drag could be one such way to accomplish this, Bevilacqua said.

Bevilacqua joined the Rensselaer School of Engineering faculty in 2010, before which he served as a lecturer and researcher at the Naval Postgraduate School in Monterey, Calif. He earned his laurea degree in aerospace engineering, and his doctoral degree in mathematical methods and models for applied sciences, both from the Sapienza University of Rome.

He is also a faculty member of the Center for Automation Technologies and Systems (CATS) at Rensselaer.


Source: Rensselaer Polytechnic Institute

Tiny 3D chips: Researchers develop a new approach to producing microchips

MIT News
Feb 29, 2012

A new approach helps researchers make tiny three-dimensional structures. Pictured are two packaged microchips, each with tiny bridges fabricated on their surfaces.

Microelectromechanical systems, or MEMS, are small devices with huge potential. Typically made of components less than 100 microns in size — the diameter of a human hair — they have been used as tiny biological sensors, accelerometers, gyroscopes and actuators.

For the most part, existing MEMS devices are two-dimensional, with functional elements engineered on the surface of a chip. It was thought that operating in three dimensions — to detect acceleration, for example — would require complex manufacturing and costly merging of multiple devices in precise orientations.

Now researchers at MIT have come up with a new approach to MEMS design that enables engineers to design 3-D configurations, using existing fabrication processes; with this approach, the researchers built a MEMS device that enables 3-D sensing on a single chip. The silicon device, not much larger than Abraham Lincoln’s ear on a U.S. penny, contains microscopic elements about the width of a red blood cell that can be engineered to reach heights of hundreds of microns above the chip’s surface.

Fabio Fachin, a postdoc in the Department of Aeronautics and Astronautics, says the device may be outfitted with sensors, placed atop and underneath the chip’s minuscule bridges, to detect three-dimensional phenomena such as acceleration. Such a compact accelerometer may be useful in several applications, including autonomous space navigation, where extremely accurate resolution of three-dimensional acceleration fields is key.

“One of the main driving factors in the current MEMS industry is to try to make fully three-dimensional devices on a single chip, which would not only enable real 3-D sensing and actuation, but also yield significant cost benefits,” Fachin says. “A MEMS accelerometer could give you very accurate acceleration [measurements] with a very small footprint, which in space is critical.”

Fachin collaborated with Brian Wardle, an associate professor of aeronautics and astronautics at MIT, and Stefan Nikles, a design engineer at MEMSIC, an Andover, Mass., company that develops wireless-sensor technology. The team outlined the principles behind their 3-D approach in a paper accepted for publication in the Journal of Microelectromechanical Systems.
To read more click here...

Job Posting: Strayer University

The private, for-profit educational institution is hiring a Student Financial Services Ombudsman. The position is primarily responsible for handling unresolved loan disputes between students and the university. (According to the U.S. Department of Education, the repayment rate of federal student loans at Strayer University is about 24%.) The position will be full time and based in Northern Virginia. 

According to the job posting, the Ombudsman will review and attempt to informally resolve disputes, maintain confidentiality, and remain independent, neutral and impartial. However, the posting also indicates that the Ombuds will be assisted by the Strayer University Legal team. This appears to be a new position and there is nothing on the Strayer website about the Ombuds program. No qualifications, salary or deadline indicated. (Strayer Recruiter; U.S. Dept. of Ed.)

Interview of DePaul University's Ombuds

Rev. Craig Mousin, has served as the Ombudsperson for faculty and staff at the private university in Chicago for the past 11 years. He is a minister with the United Church of Christ, a lawyer, and a law professor at DePaul. Before becoming an Ombuds, he was the director of the Center for Church-State Studies for the DePaul Law School.



Mousin was interviewed recently by the campus newspaper. 

The DePaulia: Finally, what is the goal of your position here as an ombudsperson? 

Craig Mousin: The overall goal of our office is to resolve conflicts peacefully and to help DePaul fulfill its Vincentian mission. We try to facilitate direct and candid conversations between all members of the university community and attempt to prevent miscommunication. The work being done in this office seems to affect nearly every aspect of the university because they cater to all faculty and staff members. The ombudsperson office is a division of the Office of Mission and Values. 

(The DePaulia.) 

Mousin published an article in the latest Journal of IOA and will be speaking at the IOA 2012 conference. 

Related posts: DePaul Ombuds Talks About Diversity and Workplace Conflict; Recap of 2010 Midwest Meeting of University & College Ombuds; Journal of IOA Explores Issues of Confidentiality; IOA Opens Registration and Posts Agenda for 2012 Conference.

New energy storage device based on water: Solution for increasing energy demand

Engineerblogger
Feb 27, 2012

Semiconductor and Energy Conversion”-group (pictured left to right): Alberto Battistel (Ph.D. Student), Dr. Edyta Madej (PostDoc), Dr. Fabio La Mantia (Junior Group Leader), Dr. Jelena Stojadinovic (PostDoc), Mu Fan (Ph.D. Student)

The global energy demand is still increasing. However, today's concepts for power generation aren't able to deliver the amount of electricity, which is needed in the future. Dr. Fabio La Mantia, junior group leader of the “Semiconductor and Energy Conversion”-group (Center for Electrochemical Sciences) of the Ruhr-Universität Bochum, is working on a solution for the problem. In March he and his team are going to start a project, with the ambition to develop an aqueous lithium-ion battery. They want to produce an accumulator, which is working at two volt with a three times decreased cost, compared to conventional ones. The Federal Ministry of Education and Research is going to support the project with 1.424.000 Euro for a duration of five years.

Renewable energies fall short

The current world-wide consumption is predicted by experts to rise up from 13 to 25 terawatt by 2050. Renewable energies are only able to supply ten percent of the need, because they are expensive and not always available in the same extent. This applies especially for solar and wind energy. “Fast and economical systems, to cache the current, are in demand”, explains La Mantia. The idea is to produce batteries, which are appropriate for the application in the power grid.

Higher performance and lifespan

General lithium-ion batteries are based on organic solvents. They are the standard for all portable devices. However, for the use in power supply systems, they are too expensive and unsafe. They overheat too quickly, which can cause short circuits. To improve the performance, lifespan, energy density and the price-performance ratio, the young scientists concentrate themselves on the combination of appropriate materials, separators, cells and aqueous electrolytes (liquid conductor of electricity).

Source: Ruhr-University Bochum

Reduction in U.S. carbon emissions attributed to cheaper natural gas

Harvard University
Feb 27, 2012

Changes in carbon dioxide emissions from the power sector in the nine census regions of the contiguous United States, 2008-2009. Image courtesy of Xi Lu.

In 2009, when the United States fell into economic recession, greenhouse gas emissions also fell, by 6.59 percent relative to 2008.

In the power sector, however, the recession was not the main cause.

Researchers at the Harvard School of Engineering and Applied Sciences (SEAS) have shown that the primary explanation for the reduction in CO2 emissions from power generation that year was that a decrease in the price of natural gas reduced the industry's reliance on coal.

According to their econometric model, emissions could be cut further by the introduction of a carbon tax, with negligible impact on the price of electricity for consumers.

A regional analysis, assessing the long-term implications for energy investment and policy, appears in the journal Environmental Science and Technology.

In the United States, the power sector is responsible for 40 percent of all carbon emissions. In 2009, CO2 emissions from power generation dropped by 8.76 percent. The researchers attribute that change to the new abundance of cheap natural gas.

"Generating 1 kilowatt-hour of electricity from coal releases twice as much CO2 to the atmosphere as generating the same amount from natural gas, so a slight shift in the relative prices of coal and natural gas can result in a sharp drop in carbon emissions," explains Michael B. McElroy, Gilbert Butler Professor of Environmental Studies at SEAS, who led the study.

"That's what we saw in 2009," he says, "and we may well see it again."

Patterns of electricity generation, use, and pricing vary widely across the United States. In parts of the Midwest, for instance, almost half of the available power plants (by capacity) were built to process coal. Electricity production can only switch over to natural gas to the extent that gas-fired plants are available to meet the demand. By contrast, the Pacific states and New England barely rely on coal, so price differences there might make less of an impact.

To account for the many variables, McElroy and his colleagues at SEAS developed a model that considers nine regions separately.
To read more click here...

Mechanism Behind Capacitor’s High-Speed Energy Storage Discovered

Engineerblogger
Feb 27, 2012

Researchers at North Carolina State University have discovered the means by which a polymer known as PVDF enables capacitors to store and release large amounts of energy quickly. Their findings could lead to much more powerful and efficient electric cars.

Capacitors are like batteries in that they store and release energy. However, capacitors use separated electrical charges, rather than chemical reactions, to store energy. The charged particles enable energy to be stored and released very quickly. Imagine an electric vehicle that can accelerate from zero to 60 miles per hour at the same rate as a gasoline-powered sports car. There are no batteries that can power that type of acceleration because they release their energy too slowly. Capacitors, however, could be up to the job – if they contained the right materials.

NC State physicist Dr. Vivek Ranjan had previously found that capacitors which contained the polymer polyvinylidene fluoride, or PVDF, in combination with another polymer called CTFE, were able to store up to seven times more energy than those currently in use.

“We knew that this material makes an efficient capacitor, but wanted to understand the mechanism behind its storage capabilities,” Ranjan says.

In research published in Physical Review Letters, Ranjan, fellow NC State physicist Dr. Jerzy Bernholc and Dr. Marco Buongiorno-Nardelli from the University of North Texas, did computer simulations to see how the atomic structure within the polymer changed when an electric field was applied. Applying an electric field to the polymer causes atoms within it to polarize, which enables the capacitor to store and release energy quickly. They found that when an electrical field was applied to the PVDF mixture, the atoms performed a synchronized dance, flipping from a non-polar to a polar state simultaneously, and requiring a very small electrical charge to do so.

“Usually when materials change from a polar to non-polar state it’s a chain reaction – starting in one place and then moving outward,” Ranjan explains. “In terms of creating an efficient capacitor, this type of movement doesn’t work well – it requires a large amount of energy to get the atoms to switch phases, and you don’t get out much more energy than you put into the system.

“In the case of the PVDF mixture, the atoms change their state all at once, which means that you get a large amount of energy out of the system at very little cost in terms of what you need to put into it. Hopefully these findings will bring us even closer to developing capacitors that will give electric vehicles the same acceleration capabilities as gasoline engines.”

Source: North Carolina State University

Additional Information:

• The abstract "Electric Field Induced Phase Transitions in Polymers: A Novel Mechanism for High Speed Energy Storage" published on February 23, 2012 in the American Physical Society (APS)

Graphyne May Be Better than Graphene

Engineerblogger
Feb 27, 2012

Stretched honeycomb. The carbon lattice in this 6,6,12-graphyne has a rectangular symmetry, unlike the hexagonal symmetry of graphene. Credit: APS

Sheets of single-layer carbon with a variety of bonding patterns may have properties similar to the wonder material graphene, according to new computer simulations.

Super-strong, highly conducting graphene is the hottest ticket in physics, but new computer simulations suggest that materials called graphynes could be just as impressive. Graphynes are one-atom-thick sheets of carbon that resemble graphene, except in the type of atomic bonds. Only small pieces of graphyne have so far been fabricated, but the new simulations, described in Physical Review Letters, may inspire fresh efforts to construct larger samples. The authors show that three different graphynes have a graphenelike electronic structure, which results in effectively massless electrons. The unique symmetry in one of these graphynes may potentially lead to new uses in electronic devices, beyond those of graphene.

The singe-atom-thick structure of carbon atoms arranged in a honeycomb pattern, known as graphene, was first isolated in a lab 2004, but many of its remarkable electronic properties were revealed by theorists 60 years before. The most striking aspect of graphene is that its electronic energy levels, or “bands,” produce conduction electrons whose energies are directly proportional to their momentum. This is the energy-momentum relationship exhibited by photons, which are massless particles of light. Electrons and other particles of matter normally have energies that depend on the square of their momentum.

When the bands are plotted in three dimensions, the photonlike energy-momentum relationship appears as an inverted cone, called a Dirac cone. This unusual relationship causes conduction electrons to behave as though they were massless, like photons, so that all of them travel at roughly the same speed (about 0.3 percent of the speed of light). This uniformity leads to a conductivity greater than copper.

Graphynes differ from their carbon cousin graphene in that their 2D framework contains triple bonds in addition to double bonds. These triple bonds open up a potentially limitless array of different geometries beyond the perfect hexagonal lattice of graphene, although only small pieces of graphynes have been synthesized so far. Still, this hasn’t stopped theorists from exploring their properties [1]. Recent work gave an indication that certain graphynes might have Dirac cones [2]. To verify this, Andreas Görling of the University of Erlangen-Nürnberg in Germany and his colleagues have now performed a more rigorous investigation of graphyne using state-of-the-art methods.

The team selected three graphynes to study: two with hexagonal symmetry and a third with rectangular symmetry. The researchers first checked that these graphynes were stable by simulating their vibrations and checking that they returned to their original shape. They then determined the band structure using density-functional theory, the gold standard for dealing with the hopelessly large number of electron-electron interactions inside a material. The simulations showed that all three graphynes had Dirac cones. This was surprising in the case of the rectangular graphyne, Görling says, because most people assumed this sort of electronic structure was tied to hexagonal symmetry. The implication is that many other materials (some containing atoms other than carbon) could have Dirac cones.

On closer examination of the rectangularly symmetric graphyne, the team discovered that the Dirac cones were not perfectly conical. A vertical slice in the direction of the “short side” of the rectangular lattice gave an inverted triangle as would be expected, but in the perpendicular direction, parallel to the “long side,” the cross section was curved, like a triangle bent towards a parabola. This distortion should lead to a conductance that depends on the direction of the current, a property not found in graphene but one that could be exploited in nanoscale electronic devices, Görling says. Another potentially useful property of this graphyne is that it should naturally contain conducting electrons and should not require noncarbon “dopant” atoms to be added as a source of electrons, as is required for graphene.

The big challenge now is to make large graphyne samples. “Organic chemists like myself can synthesize (often with difficulty) complex molecular subunits,” but these small sections of graphyne do not exhibit the expected properties of a large lattice, says Michael Haley of the University of Oregon in Eugene. Andre Geim of the University of Manchester, UK, who was awarded the 2010 Nobel Prize for his experimental work on graphene, says that graphyne is “an extremely interesting material, and this report adds to the excitement.” He only hopes it won’t take 60 years for experimentalists to make the excitement a reality this time.

Source: American Physical Society

Additional Information:

• The abstract "Competition for Graphene: Graphynes with Direction-Dependent Dirac Cones" by Daniel Malko, Christian Neiss, Francesc Viñes, and Andreas Görling in the American Physical Society (APS), published 24 February 2012.   

• (1) R. H. Baughman, H. Eckhardt, and M. Kertesz, “Structure‐property predictions for new planar forms of carbon: Layered phases containing sp² and sp atoms,” J. Chem. Phys. 87, 6687 (1987).

•  (2)A. N. Enyashin and A. L. Ivanovskii, “Graphene allotropes,” Phys. Stat. Sol. B 248, 1879 (2011).

Team’s efficient unmanned aircraft jetting toward commercialization

Engineerblogger
Feb 25, 2012

CU-Boulder Assistant Professor Ryan Starkey, left, with some members of his team, looks over engine model nozzles for a first-of-its-kind supersonic unmanned aircraft vehicle, visible in the rendering on the computer screen. From left are Starkey; Sibylle Walter, doctoral degree student; Josh Fromm, master's degree graduate; and Greg Rancourt, master's degree student. (Photo by Glenn Asakawa/University of Colorado)

Propulsion by a novel jet engine is the crux of the innovation behind a University of Colorado Boulder-developed aircraft that’s accelerating toward commercialization.

Jet engine technology can be small, fuel-efficient and cost-effective, at least with Assistant Professor Ryan Starkey’s design. The CU-Boulder aerospace engineer, with a team of students, has developed a first-of-its-kind supersonic unmanned aircraft vehicle, or UAV. The UAV, which is currently in a prototype state, is expected to fly farther and faster -- using less fuel -- than anything remotely similar to date.

The fuel efficiency of the engine that powers the 50-kilogram UAV is already double that of similar-scale engines, and Starkey says he hopes to double that efficiency again through further engineering.

A rendering, created by master's degree student Greg Rancourt, of the UAV. (Courtesy Ryan Starkey)

Starkey says his UAV could be used for everything from penetrating and analyzing storms to military reconnaissance missions -- both expeditions that can require the long-distance, high-speed travel his UAV will deliver -- without placing human pilots in danger. The UAV also could be used for testing low-sonic-boom supersonic transport aircraft technology, which his team is working toward designing.

The UAV is intended to shape the next generation of flight experimentation after post-World War II rocket-powered research aircraft, like the legendary North American X-15, have long been retired.

“I believe that what we’re going to do is reinvigorate the testing world, and that’s what we’re pushing to do,” said Starkey. “The group of students who are working on this are very excited because we’re not just creeping into something with incremental change, we’re creeping in with monumental change and trying to shake up the ground.”

Its thrust capacity makes the aircraft capable of reaching Mach 1.4, which is slightly faster than the speed of sound. Starkey says that regardless of the speed reached by the UAV, the aircraft will break the world record for speed in its weight class.

Its compact airframe is about 5 feet wide and 6 feet long. The aircraft costs between $50,000 and $100,000 -- a relatively small price tag in a field that can advance only through testing, which sometimes means equipment loss.

Starkey’s technology -- three years in the making at CU-Boulder -- is transitioning into a business venture through his weeks-old Starkey Aerospace Corp., called Starcor for short. The company was incubated by eSpace, which is a CU-affiliated nonprofit organization that supports entrepreneurial space companies. Starkey’s UAV already has garnered interest from the U.S. Army, Navy, Defense Advanced Research Projects Agency and NASA. The acclaimed Aviation Week publication also has highlighted Starkey’s UAV.

Starkey says technology transfer is important because it parlays university research into real-life applications that advance societies and contribute to local and global economies.

It also can provide job tracks for undergraduate and graduate students, says Starkey who’s bringing some of the roughly 50 students involved in UAV development into his budding Starcor.

“There are great students everywhere, but one of the reasons why I came to CU was because of how the students are trained. We definitely make sure they understand everything from circuit board wiring to going into the shop and building something,” said Starkey. “It makes them very effective and powerful even as fresh engineers with bachelor’s degrees. They’re very good students to hire. That’s a piece that I’m interested in embracing -- finding the really good talent that we have right here in Colorado and pulling it into the company.”

Starkey and his students are currently creating a fully integrated and functioning engineering test unit of the UAV, which will be followed by a critical design review after resolving any problems. The building of the aircraft and process of applying for FAA approval to test it in the air will carry into next year.

Starkey’s continuing fascination with speed first began to burn inside of him when he visited Kennedy Space Center at the age of 5. “When I teach I tell my class, ‘If it goes fast and gets hot, I’m in it.’ That’s what I want to do. There needs to be fire involved somewhere.”

Source: University of Colorado at Boulder