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Showing posts with label THERMODYNAMICS. Show all posts
Showing posts with label THERMODYNAMICS. Show all posts

A new wireless energy transfer device can charge any device without using cables

Written By Unknown on Thursday, January 8, 2015 | 4:58 AM

Researchers have designed a new device for wireless energy transfer that will charge mobile phones or laptops without the need for wires. Credit: UPV
Researchers at the Universitat Politècnica de València (UPV) have designed a new device for wireless energy transfer that will, for example, charge mobile phones or laptops without needing wires.

The system, patented by the UPV, is based on the use of resonators designed with radial photonic crystals; one of them would act as an energy transmitter and the other would be set on the device that needed to be charged. Between them a phenomena known as resonant coupling is produced, which is what finally produces the charging or recharging of the equipment.

"This phenomena is produced when a resonant object is moved closer to a second resonant element and both resonance frequencies are equal or quite similar. This physical proximity produces an energy coupling from the first device, that acts as the source, to the second one, that acts as the charge," says José Sánchez-Dehesa, researcher at the Wave Phenomena 
Group of the Universitat Politècnica de València.

The device could also be used as a power supply system for equipment such as keyboards and wireless mice, speakers, etc. Besides consumer electronics, it could also be used in an industrial environment as power supply for robots or guided vehicles, and bioelectric devices (cardiac pacemakers, defibrillators, etc.)

The UPV researchers' study was released last June in the Annals of Physics magazine. After the first laboratory simulations and calculations of the system's performance, the engineers of the Wave Phenomena Group are now working on the development of the first prototype.

Technology implementation

With regard to the implementation of these devices, UPV researchers say that, "although it may seem futuristic, it is foreseeable that they become universal due to the spread of charging infrastructure in many settings. This technology could follow the same path as WIFI networks," explains Jorge Carbonell, researcher at the Wave Phenomena Group.

Source: Asociación RUVID

Software to automatically outline bones in x-rays

Written By Unknown on Wednesday, January 7, 2015 | 11:37 PM

An image from the Bone Finder software. Credit: Image courtesy of Manchester University
Research into disorders such as arthritis is to be helped by new software developed at the University of Manchester which automatically outlines bones -- saving thousands of hours of manual work.

Amidst a national shortage of radiographers in the UK and an increasing requirement for researchers to work with large databases of radiograph images, the software which is being funded by the Engineering and Physical Sciences Research Council, is being designed to automatically pick out the shapes of bones in the images, rather than relying on individual researchers.

The system can already identify hips, but the researchers from the University's Institute of Population Health will now adapt it to map out knees and hands and to be able to learn to identify other bones and structures within the body.

The funding will allow further development to ensure the system is accurate enough that it can be used in hospitals to help provide faster diagnosis of problems in patients.

Professor of Computer Vision, Tim Cootes said: "Mapping the outlines of bones from radiographs is hard work that takes time and skill. When researchers into conditions like arthritis are working with hundreds of images, it's a very inefficient way of obtaining data.

"The idea of this software is to take the routine tasks out of human hands, so scientists can 
focus on drawing conclusions and developing treatments."

The funding of £300,000 lasts for three years and builds on earlier work which developed software, called Bonefinder, to identify problems and find the outlines of hips. This free software has been adopted by a number of research groups, including some based in Oxford and California.

Professor Cootes added: "We have a growing problem with arthritis which affects more than 30% of over 65s and costs around £30 billion to the UK economy year.

"Ultimately we want to get this technology into hospitals where it can save time and resources for the benefit of patients."

Source: Manchester University

Instant-start computers possible with new breakthrough

Written By Unknown on Tuesday, January 6, 2015 | 6:08 AM

Power button (stock image)
To encode data, today's computer memory technology uses electric currents -- a major limiting factor for reliability and shrinkability, and the source of significant power consumption. If data could instead be encoded without current -- for example, by an electric field applied across an insulator -- it would require much less energy, and make things like low-power, instant-on computing a ubiquitous reality.

A team at Cornell University led by postdoctoral associate John Heron, who works jointly with Darrell Schlom, professor of Industrial Chemistry in the Department of Materials Science and Engineering, and Dan Ralph, professor of Physics in the College of Arts and Sciences, has made a breakthrough in that direction with a room-temperature magnetoelectric memory device. Equivalent to one computer bit, it exhibits the holy grail of next-generation nonvolatile memory: magnetic switchability, in two steps, with nothing but an electric field. Their results were published online Dec. 17 in Nature, along with an associated "News and Views" article.

"The advantage here is low energy consumption," Heron said. "It requires a low voltage, without current, to switch it. Devices that use currents consume more energy and dissipate a significant amount of that energy in the form of heat. That is what's heating up your computer and draining your batteries."

The researchers made their device out of a compound called bismuth ferrite, a favorite among materials mavens for a spectacularly rare trait: It's both magnetic -- like a fridge magnet, it has its own, permanent local magnetic field -- and also ferroelectric, meaning it's always electrically polarized, and that polarization can be switched by applying an electric field. Such so-called ferroic materials are typically one or the other, rarely both, as the mechanisms that drive the two phenomena usually fight each other.

This combination makes it a "multiferroic" material, a class of compounds that has enjoyed a buzz over the last decade or so. Paper co-author Ramamoorthy Ramesh, Heron's Ph.D. adviser at University of California, Berkeley, first showed in 2003 that bismuth ferrite can be grown as extremely thin films and can exhibit enhanced properties compared to bulk counterparts, igniting its relevance for next-generation electronics.

Because it's multiferroic, bismuth ferrite can be used for nonvolatile memory devices with relatively simple geometries. The best part is it works at room temperature; other scientists, including Schlom's group, have demonstrated similar results with competing materials, but at unimaginably cold temperatures, like 4 Kelvin (-452 Fahrenheit) -- not exactly primed for industry. "The physics has been exciting, but the practicality has been absent," Schlom said.
A key breakthrough by this team was theorizing, and experimentally realizing, the kinetics of the switching in the bismuth ferrite device. They found that the switching happens in two distinct steps. One-step switching wouldn't have worked, and for that reason theorists had previously thought what they have achieved was impossible, Schlom said. But since the switching occurs in two steps, bismuth ferrite is technologically relevant.

The multiferroic device also seems to require an order of magnitude lower energy than its chief competitor, a phenomenon called spin transfer torque, which Ralph also studies, and that harnesses different physics for magnetic switching. Spin transfer torque is already used commercially but in only limited applications. They have some work to do; for one thing they made just a single device, and computer memory involves billions of arrays of such devices. They need to ramp up its durability, too. But for now, proving the concept is a major leap in the right direction.

"Ever since multiferroics came back to life around 2000, achieving electrical control of magnetism at room temperature has been the goal," Schlom said.

Source: Cornell University

Acoustic levitation made simple

Written By Unknown on Monday, January 5, 2015 | 8:29 PM

Levitation of expanded polystyrene particles by ultrasonic sound waves. Credit: M. Andrade/University of São Paulo
A team of researchers at the University of São Paulo in Brazil has developed a new levitation device that can hover a tiny object with more control than any instrument that has come before.

Featured on this week's cover of the journal Applied Physics Letters, from AIP Publishing, the device can levitate polystyrene particles by reflecting sound waves from a source above off a concave reflector below. Changing the orientation of the reflector allow the hovering particle to be moved around.

Other researchers have built similar devices in the past, but they always required a precise setup where the sound source and reflector were at fixed "resonant" distances. This made controlling the levitating objects difficult. The new device shows that it is possible to build a 
"non-resonant" levitation device -- one that does not require a fixed separation distance between the source and the reflector.

This breakthrough may be an important step toward building larger devices that could be used to handle hazardous materials, chemically-sensitive materials like pharmaceuticals -- or to provide technology for a new generation of high-tech, gee-whiz children's toys.

"Modern factories have hundreds of robots to move parts from one place to another," said Marco Aurélio Brizzotti Andrade, who led the research. "Why not try to do the same without touching the parts to be transported?"

The device Andrade and his colleagues devised was only able to levitate light particles (they tested it polystyrene blobs about 3 mm across). "The next step is to improve the device to levitate heavier materials," he said.

How the Acoustic Levitation Device Works

In recent years, there has been significant progress in the manipulation of small particles by acoustic levitation methods, Andrade said.

In a typical setup, an upper cylinder will emit high-frequency sound waves that, when they hit the bottom, concave part of the device, are reflected back. The reflected waves interact with newly emitted waves, producing what are known as standing waves, which have minimum acoustic pressure points (or nodes), and if the acoustical pressure at these nodes is strong enough, it can counteract the force of gravity and allow an object to float.

The first successful acoustical levitators could successfully trap small particles in a fixed position, but new advances in the past year or so have allowed researchers not only to trap but also to transport particles through short distances in space.

These were sorely won victories, however. In every levitation device made to date, the distance between the sound emitter and the reflector had to be carefully calibrated to achieve resonance before any levitation could occur. This meant that the separation distance had to be equal to a multiple of the half-wavelength of the sound waves. If this separation distance were changed even slightly, the standing wave pattern would be destroyed and the levitation would be lost.

The new levitation device does not require such a precise separation before operation. In fact, the distance between the sound emitter and the reflector can be continually changed in mid-flight without affecting the levitation performance at all, Andrade said.
"Just turn the levitator on and it is ready," Andrade said.

Source: American Institute of Physics (AIP)

Successful launch of NASA's Orion spacecraft heralds first step on journey to Mars

Written By Unknown on Friday, January 2, 2015 | 5:36 PM

The United Launch Alliance Delta IV Heavy rocket, with NASA's Orion spacecraft mounted atop, lifts off from Cape Canaveral Air Force Station's Space Launch Complex 37 at at 7:05 a.m. EST, Friday, Dec. 5. Credit: NASA/Bill Ingalls
NASA marked a critical step on the journey to Mars with its Orion spacecraft during a roaring liftoff into the dawn sky over eastern Florida on Friday, Dec. 5, 2014, aboard a Delta IV Heavy rocket.

Once on its way, the Orion spacecraft accomplished a series of milestones as it jettisoned a set of fairing panels around the service module before the launch abort system tower pulled itself away from the spacecraft as planned.

The spacecraft and second stage of the Delta IV rocket settled into an initial orbit about 17 minutes after liftoff. Flight controllers put Orion into a slow roll to keep its temperature controlled while the spacecraft flew through a 97-minute coast phase.

The cone-shaped spacecraft did not carry anyone inside its cabin but is designed to take astronauts farther into space than ever before in the future.

Orion's first flight test is expected to be one for the books: the first mission since Apollo to carry a spacecraft built for humans to deep space, the first time NASA's next-generation spacecraft is tested against the challenges of space, and the first operational test of a heat shield strong enough to protect against 4,000-degree temperatures.

From today's launch on a gigantic United Launch Alliance Delta IV Heavy from Florida to the expected splashdown under billowing parachutes, the mission will test many of the riskiest events Orion will see when it sends astronauts to an asteroid and onward toward Mars in the future.

"Orion is the exploration spacecraft for NASA, and paired with the Space Launch System, or SLS, rocket it will allow us to explore the solar system," said Mark Geyer, program manager of Orion, which is based at Johnson Space Center in Houston.

While the Delta IV Heavy will send Orion on its flight test, SLS will launch the spacecraft on future missions.

NASA's Orion program has arrived at a fulcrum point that will tell its designers and builders how it stacks up technically. It also will show that NASA is ready to take the next step on its journey into deep space -- and ultimately to Mars.

So even though Orion is poised for a mere 4 1/2-hour, two-orbit mission without anyone on board, the cone-shaped craft needs to perform its roster of tasks well, including an all-important descent through Earth's atmosphere and splashdown.

"Really, we're going to test the riskiest parts of the mission," Geyer said. "Ascent, entry and things like fairing separations, Launch Abort System jettison, the parachutes plus the navigation and guidance -- all those things are going to be tested. Plus we'll fly into deep 
space and test the radiation effects on those systems."

The flight test began at Space Launch Complex 37 at Cape Canaveral Air Force Station.

The second stage will ignite again about two hours into the flight to send Orion through the Van Allen radiation belts and to a peak altitude of 3,609 miles, some 15 times higher than the International Space Station. This is going to be a key point in the test flight as instruments inside Orion record the radiation doses inside the cabin -- critical data for mission planners considering the best way to safely send astronauts into deep space in the future. Orion's cameras will be turned off during its passes through the belts to protect them.

Three hours, 23 minutes into flight, the Orion crew module will fly on its own following separation from its service module and the Delta IV Heavy second stage. The spacecraft will be aimed at Earth's atmosphere and it will be up to Orion's onboard computers to set the spacecraft in the right position so its base heat shield can bear the brunt of the intense reentry heat.

Hitting the atmosphere at 20,000 mph four hours and 13 minutes after launch, Orion will encounter about 80 percent of the heat it would endure during a return from lunar orbit with astronauts aboard. Ground controllers will lose contact with Orion for 2 1/2 minutes during reentry when the spacecraft is surrounded by plasma. They should regain communications with the craft just before the forward bay cover is jettisoned in a process that will begin the parachute deployment. After about four hours, 23 minutes, Orion will be bobbing in the Pacific Ocean off the coast of Baja California as recovery forces move in.

Teams from NASA's Ground Systems Development and Operations Program based at Kennedy will work with U.S. Navy and Orion prime contractor Lockheed Martin personnel to bring the spacecraft into the well deck of the USS Anchorage, an amphibious ship with a protective enclosure that will allow Orion to basically float onboard without having to be lifted by a crane. A second ship, the USNS Salvor, also will be on hand as a backup.
Many aspects of the mission point to a future as ambitious as any time in NASA's 50-plus-year history.

With lessons learned from Orion's flight test, NASA can improve the spacecraft's design 
while building the first Space Launch System rocket, a heavy booster with enough power to send the next Orion to a distant retrograde orbit around the moon for Exploration Mission-
1. Following that, astronauts are gearing up to fly Orion on the second SLS rocket on a mission that will return astronauts to deep space for the first time in more than 40 years. 

These adventures will set NASA up for future human missions to an asteroid and even on the journey to Mars.

"To be able to even think about going to an asteroid and to be able to think about this kind of exploration, that's very exciting," Kennedy Space Center Director Bob Cabana said. "I think there's a genuine, positive atmosphere, and I don't think it's confined to just Kennedy. You go across all the NASA centers and I think the team is really excited about the future."
And while all that work is happening on the ground, astronauts on the International Space Station will continue the groundbreaking research that is already adding to humanity's understanding of everything from long-duration spaceflight to the continued experimentation on products and processes that improve life on Earth.

None of those plans has caused NASA or Lockheed Martin, which is operating this flight test, to look past the crucial steps needed to make this mission a success.

Lockheed Martin assembled the spacecraft in the high bay at the Operations and Checkout Building at NASA's Kennedy Space Center in Florida, a facility recently named for Neil Armstrong, first man to walk on the moon.

While the mission is expected to make a huge impact on the way the next Orion is built, many lessons from the buildup of this spacecraft are already being incorporated in the planning for the next one, Geyer said.

"This has shown it's a good design, it's a good mission and now it's time to go fly," Geyer said.

Source: NASA

Offsetting global warming: Targeting solar geoengineering to minimize risk and inequality

Written By Unknown on Sunday, December 7, 2014 | 5:27 PM

Sunset in the Arctic. A new study at Harvard explores the feasibility of using cautious and targeted solar geoengineering to counter the loss of Arctic sea ice.
A new study suggests that solar geoengineering can be tailored to reduce inequality or to manage specific risks like the loss of Arctic sea ice. By tailoring geoengineering efforts by region and by need, a new model promises to maximize the effectiveness of solar radiation management while mitigating its potential side effects and risks.

Developed by a team of leading researchers, the study was published in the November issue of Nature Climate Change.

Solar geoengineering, the goal of which is to offset the global warming caused by greenhouse gases, involves reflecting sunlight back into space. By increasing the concentrations of aerosols in the stratosphere or by creating low-altitude marine clouds, the as-yet hypothetical solar geoengineering projects would scatter incoming solar heat away from Earth's surface.

Critics of geoengineering have long warned that such a global intervention would have unequal effects around the world and could result in unforeseen consequences. They argue that the potential gains may not be worth the risk.

Gordon McKay Professor of Applied Physics at the Harvard School of Engineering and Applied Sciences (SEAS) and Professor of Public Policy at Harvard Kennedy School. "Instead, we can be thoughtful about various tradeoffs to achieve more selective results, such as the trade-off between minimizing global climate changes and minimizing residual changes at the worst-off location."
The study -- developed in collaboration with Douglas G. MacMartin of the California Institute of Technology, Ken Caldeira of the Carnegie Institution for Science, and Ben Kravitz, formerly of Carnegie and now at the Department of Energy -- explores the feasibility of using solar geoengineering to counter the loss of Arctic sea ice.

"There has been a lot of loose talk about region-specific climate modification. By contrast, our research uses a more systematic approach to understand how geoengineering might be used to limit a specific impact. We found that tailored solar geoengineering might limit Arctic sea ice loss with several times less total solar shading than would be needed in a uniform case."

Generally speaking, greenhouse gases tend to suppress precipitation, and an offsetting reduction in the amount of sunlight absorbed by Earth would not restore this precipitation. Both greenhouse gases and aerosols affect the distribution of heat and rain on this planet, but they change the temperature and precipitation in different ways in different places. The researchers suggest that varying the amount of sunlight deflected away from Earth both regionally and seasonally could combat some of this problem.

"These results indicate that varying geoengineering efforts by region and over different periods of time could potentially improve the effectiveness of solar geoengineering and reduce climate impacts in at-risk areas," says co-author Ken Caldeira, Senior Scientist in the Department of Global Ecology at the Carnegie Institution for Science.

The researchers note that while their study used a state-of-the-art model, any real-world estimates of the possible impact of solar radiation management would need to take into account various uncertainties. Further, any interference in Earth's climate system, whether intentional or unintentional, is likely to produce unanticipated outcomes.

"While more work needs to be done, we have a strong model that indicates that solar geoengineering might be used in a far more nuanced manner than the uniform one-size-fits-all implementation that is often assumed. One might say that one need not think of it as a single global thermostat. This gives us hope that if we ever do need to implement engineered solutions to combat global warming, that we would do so with a bit more confidence and a great ability to test it and control it."


Source: Harvard University

Injecting sulfate particles into stratosphere won't fully offset climate change

A polar bear walks along an expanse of open water at the edge of Hudson Bay near Churchill, Manitoba, in 2011. The bears need pack ice to hunt for food, primarily seals, but climate change brings open water more often than it used to. Polar bears have been listed as a threatened species. Credit: Cecilia Bitz, U. of Washington
As the reality and the impact of climate warming have become clearer in the last decade, researchers have looked for possible engineering solutions -- such as removing carbon dioxide from the atmosphere or directing the sun's heat away from Earth -- to help offset rising temperatures.

New University of Washington research demonstrates that one suggested method, injecting sulfate particles into the stratosphere, would likely achieve only part of the desired effect, and could carry serious, if unintended, consequences.

The lower atmosphere already contains tiny sulfate and sea salt particles, called aerosols, that reflect energy from the sun into space. Some have suggested injecting sulfate particles directly into the stratosphere to enhance the effect, and also to reduce the rate of future warming that would result from continued increases in atmospheric carbon dioxide.

But a UW modeling study shows that sulfate particles in the stratosphere will not necessarily offset all the effects of future increases in atmospheric carbon dioxide.

Additionally, there still is likely to be significant warming in regions where climate change impacts originally prompted a desire for geoengineered solutions, said Kelly McCusker, a UW doctoral student in atmospheric sciences.

The modeling study shows that significant changes would still occur because even increased aerosol levels cannot balance changes in atmospheric and oceanic circulation brought on by higher levels of atmospheric carbon dioxide.

"There is no way to keep the climate the way it is now. Later this century, you would not be able to recreate present-day Earth just by adding sulfate aerosols to the atmosphere," McCusker said.
She is lead author of a paper detailing the findings published online in December in the Journal of Climate. Coauthors are UW atmospheric sciences faculty David Battisti and Cecilia Bitz.

Using the National Center for Atmospheric Research's Community Climate System Model version 3 and working at the Texas Advanced Computing Center, the researchers found that there would, in fact, be less overall warming with a combination of increased atmospheric aerosols and increased carbon dioxide than there would be with just increased carbon dioxide.

They also found that injecting sulfate particles into the atmosphere might even suppress temperature increases in the tropics enough to prevent serious food shortages and limit negative impacts on tropical organisms in the coming decades.

But temperature changes in polar regions could still be significant. Increased winter surface temperatures in northern Eurasia could have serious ramifications for Arctic marine mammals not equipped to adapt quickly to climate change. In Antarctic winters, changes in surface winds would also bring changes in ocean circulation with potentially significant consequences for ice sheets in West Antarctica.

Even with geoengineering, there still could be climate emergencies -- such as melting ice sheets or loss of polar bear habitat -- in the polar regions, the scientists concluded. They added that the odds of a "climate surprise" would be high because the uncertainties about the effects of geoengineering would be added to existing uncertainties about climate change.

The research was funded by the Tamaki Foundation and the National Science Foundation.

Source: University of Washington

Oklahoma earthquakes induced by wastewater injection by disposal wells, study finds

Written By Unknown on Wednesday, October 29, 2014 | 7:58 PM

House damage in central Oklahoma from the magnitude 5.6 earthquake on Nov. 6, 2011. Credit: Brian Sherrod, USGS
The dramatic increase in earthquakes in central Oklahoma since 2009 is likely attributable to subsurface wastewater injection at just a handful of disposal wells, finds a new study to be published in the journal Science on July 3, 2014.

The research team was led by Katie Keranen, professor of geophysics at Cornell University, who says Oklahoma earthquakes constitute nearly half of all central and eastern U.S. seismicity from 2008 to 2013, many occurring in areas of high-rate water disposal.

"Induced seismicity is one of the primary challenges for expanded shale gas and unconventional hydrocarbon development. Our results provide insight into the process by which the earthquakes are induced and suggest that adherence to standard best practices may substantially reduce the risk of inducing seismicity," said Keranen. "The best practices include avoiding wastewater disposal near major faults and the use of appropriate monitoring and mitigation strategies."

The study also concluded:

  • Four of the highest-volume disposal wells in Oklahoma (~0.05% of wells) are capable of triggering ~20% of recent central U.S. earthquakes in a swarm covering nearly 2,000 square kilometers, as shown by analysis of modeled pore pressure increase at relocated earthquake hypocenters.
  • Earthquakes are induced at distances over 30 km from the disposal wells. These distances are far beyond existing criteria of 5 km from the well for diagnosis of induced earthquakes.
  • The area of increased pressure related to these wells continually expands, increasing the probability of encountering a larger fault and thus increasing the risk of triggering a higher-magnitude earthquake.
"Earthquake and subsurface pressure monitoring should be routinely conducted in regions of wastewater disposal and all data from those should be publicly accessible. This should also include detailed monitoring and reporting of pumping volumes and pressures," said Keranen. 'In many states the data are more difficult to obtain than for Oklahoma; databases should be standardized nationally. Independent quality assurance checks would increase confidence. "

Source: Cornell University
 
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