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A chapter of the layered geological history of Mars is laid bare in this postcard from NASA’s Curiosity rover. The image shows the base of Mount Sharp, the rover’s eventual science destination. Image credit: NASA/JPL-Caltech/MSSS

Using the 100-millimeter telephoto lens and the 34-millimeter wide angle lens of the Mast Camera instrument, Curiosity beamed back a new image of the base of Mount Sharp and also sent back the first planet to planet radioed words.

Pasadena, California — NASA’s Mars Curiosity has debuted the first recorded human voice that traveled from Earth to another planet and back.

In spoken words radioed to the rover on Mars and back to NASA’s Deep Space Network (DSN) on Earth, NASA Administrator Charles Bolden noted the difficulty of landing a rover on Mars, congratulated NASA employees and the agency’s commercial and government partners on the successful landing of Curiosity earlier this month, and said curiosity is what drives humans to explore.

“The knowledge we hope to gain from our observation and analysis of Gale Crater will tell us much about the possibility of life on Mars as well as the past and future possibilities for our own planet. Curiosity will bring benefits to Earth and inspire a new generation of scientists and explorers, as it prepares the way for a human mission in the not too distant future,” Bolden said in the recorded message.

The voice playback was released along with new telephoto camera views of the varied Martian landscape during a news conference today at NASA’s Jet Propulsion Laboratory, Pasadena, California.

“With this voice, another small step is taken in extending human presence beyond Earth, and the experience of exploring remote worlds is brought a little closer to us all,” said Dave Lavery, NASA Curiosity program executive. “As Curiosity continues its mission, we hope these words will be an inspiration to someone alive today who will become the first to stand upon the surface of Mars. And like the great Neil Armstrong, they will speak aloud of that next giant leap in human exploration.”

The telephoto images beamed back to Earth show a scene of eroded knobs and gulches on a mountainside, with geological layering clearly exposed. The new views were taken by the 100-millimeter telephoto lens and the 34-milllimeter wide angle lens of the Mast Camera (Mastcam) instrument. Mastcam has photographed the lower slope of the nearby mountain called Mount Sharp.

“This is an area on Mount Sharp where Curiosity will go,” said Mastcam principal investigator Michael Malin, of Malin Space Science Systems in San Diego. “Those layers are our ultimate objective. The dark dune field is between us and those layers. In front of the dark sand you see redder sand, with a different composition suggested by its different color. The rocks in the foreground show diversity — some rounded, some angular, with different histories. This is a very rich geological site to look at and eventually to drive through.”

A drive early Monday placed Curiosity directly over a patch where one of the spacecraft’s landing engines scoured away a few inches of gravelly soil and exposed underlying rock. Researchers plan to use a neutron-shooting instrument on the rover to check for water molecules bound into minerals at this partially excavated target.

During the news conference, the rover team reported the results of a Prognostics and Health Management   test on Curio vending vms sity’s Sample Analysis at Mars (SAM) instrument, which can measure the composition of samples of atmosphere, powdered rock or soil. The amount of air from Earth’s atmosphere remaining in the instrument after Curiosity’s launch was more than expected, so a difference in pressure on either side of tiny pumps led SAM operators to stop pumping out the remaining Earth air as a precaution. The pumps subsequently worked, and a chemical analysis was completed on a sample of  Vending Telemetry  Earth air.

“As a test of the instrument, the results are beautiful confirmation of the sensitivities for identifying the gases present,” said SAM principal investigator Paul Mahaffy of NASA’s Goddard Space Flight Center in Greenbelt, Md. “We’re happy with this test and we’re looking forward to the next run in a few days when we can get Mars data.”

Curiosity already is returning more data from the Martian surface than have all of NASA’s earlier rovers combined.

“We have an international network of telecommunications relay orbiters bringing data back from Curiosity,” said JPL’s Chad Edwards, chief telecommunications engineer for NASA’s Mars Exploration Program. “Curiosity is boosting its data return by using a new capability for adjusting its transmission rate.”

Curiosity is 3 weeks into a two-year prime mission on Mars. It will use 10 science instruments to assess whether the selected study area ever has offered environmental conditions favorable for microbial life.

JPL manages the mission for NASA’s Science Mission Directorate in Washington. The rover was designed, developed and assembled at JPL. NASA’s DSN is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.

Image: NASA/JPL-Caltech/MSSS

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National Geographic knows a thing or two about quality photographs. The photo above was taken by Stefano Pesarelli in the Masai Mara National Reserve in Kenya and received an Honorable Mention in this year’s National Geographic photo contest. It’s easy to see why. It is a striking ph DIN-Rail router  oto that illustrates the amazing speed of the Cheetah.

Pesarelli says, “This panning effect, even in its imperfection, with the chromatic harmony of the background, with all the needless information eliminated and the luck of having the big cat’s lifted tail in symmetry with the impala4g modem router horns, brings the observer inside the hunting without distractions.”

If it seems all a blur of speed to you, just imagine how its prey felt. Cheetahs can reach speeds of up to 120 km/h over short distances. They stalk their prey until they are less than 30 meters away. That’s when they make the su retrofit  dden dash after them.

The contest had over 20,000 photographs submitted from over 130 countries depicting scenes of people, places, or nature. You can see all of the winners here.

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Researchers demonstrating the ability of aluminum to repel oil underwater. Courtesy of the researchers

New battery design could greatly extend the shelf life of single-use metal-air batteries for electric vehicles, off-grid storage, and other applications.

Metal-air batteries are one of the lightest and most compact types of batteries available, but they can have a major limitation: When not in use, they degrade quickly, as corrosion eats away at their metal electrodes. Now, MIT researchers have found a way to substantially reduce that corrosion, making it possible for such batteries to have much longer shelf lives.

While typical rechargeable lithium-ion batteries only lose about 5 percent of their charge after a month of storage, they are too costly, bulky, or heavy for many applications. Primary (nonrechargeable) aluminum-air batteries are much less expensive and more compact and lightweight, but they can lose 80 percent of their charge a month.

The MIT design overcomes the problem of corrosion in aluminum-air batteries by introducing an oil barrier between the aluminum electrode and the electrolyte — the fluid between the two battery electrodes that eats away at the aluminum when the battery is on standby. The oil is rapidly pumped away and replaced with electrolyte as soon as the battery is used. As a result, the energy loss is cut to just 0.02 percent a month — more than a thousandfold improvement.

The findings are reported today in the journal Science by former MIT graduate student Brandon J. Hopkins ’18, W.M. Keck Professor of Energy Yang Shao-Horn, and professor of mechanical engineering Douglas P. Hart.

Photo shows the proof-of-concept battery built by the research team to demonstrate how their system could work in practice. The battery lasted through 24 days of use and standby cycles, compared to just three days for a comparable battery without the new protective system inpower sensor place. Courtesy of the researchers

While several other methods have been used to extend the shelf life of metal-air batteries (which can use other metals such as sodium, lithium, magnesium, zinc, or iron), these methods can sacrifice performance Hopkins says. Most of the other approaches involve replacing the electrolyte with a different, less corrosive chemical formulation, but these alternatives drastically reduce the battery power.

Other methods involve pumping the liquid electrolyte out during storage and back in before use. These methods still enable significant corrosion and can clog plumbing systems in the battery pack. Because aluminum is hydrophilic (water-attracting) even after electrolyte is drained out of the pack, the remaining electrolyte will cling to the aluminum electrode surfaces. “The batteries have complex structures, so there are many corners for electrolyte to get caught in,” which results in continued corrosion, Hopkins explains.

To demonstrate the ability of aluminum to repel oil underwater, the researchers plunged this sample of aluminum into a beaker containing a layer of oil floating on water. When the sample enters the water layer, all the oil that clung to the surface on the way down quickly falls away, showing its property of underwater oleophobicity. Courtesy of the researchers.

A key to the new system is a thin membrane placed between the battery electrodes. When the battery is in use, both sides of the membrane are filled with a liquid electrolyte, but when the battery is put on standby, oil is pumped into the side closest to the aluminum electrode, which protects the aluminum surface from the electrolyte on the other side of the membrane.

The new battery system also takes advantage of a property of aluminum called “underwater oleophobicity” — that is, when aluminum is immersed in water, it repels oil from its surface. As a result, when the battery is reactivated and electrolyte is pumped back in, the electrolyte easily displaces the oil from the aluminum surface, which restores the power capabilities of the battery. Ironically, the MIT method of corrosion suppression exploits the same property of aluminum that promotes corrosion in conventional systems.

The result is an aluminum-air prototype with a much longer shelf life than that of conventional aluminum-air batteries. The researchers showed that when the battery was repeatedly used and then put on standby for one to two days, the MIT design lasted 24 days, while the conventional design lasted for only three. Even when oil and a pumping system are included in scaled-up primary aluminum-air battery packs, they are still five times lighter and twice as compact as rechargeable lithium-ion battery packs for electric vehicles, the researchers report.

Hart explains that aluminum, besides being very inexpensive, is one of the “highest chemical energy-density storage materials we know of” — that is, it is able to store and deliver more energy per pound than almost anything else, with only bromines, which are expensive and hazardous, being comparable. He says many experts think aluminum-air batteries may be the only viable replacement for lithium-ion batteries and for gasoline in cars.

Aluminum-air batteries have been used as r4g lte modemange extenders for electric vehicles to supplement built-in rechargeable batteries, to add many extra miles of driving when the built-in battery runs out. They are also sometimes used as power sources in remote locations or for some underwater vehicles. But while such batteries can be stored for long periods as long as they are unused, as soon as they are turned on for the first time, they start to degrade rapidly.

Such applications could greatly benefit from this new system, Hart explains, because with the existing versions, “you can’t really shut it off. You can flush it and delay the process, but you can’t really shut it off.” However, if the new system were used, for example, as a range extender in a car, “you could use it and then pull into your driveway and park it for a month, and then come back and still expect it to have a usable battery. … I really think this is a game-changer in terms of the use of these batteries.”

With the greater shelf life that could be afforded by this new system, the use of aluminum-air batteries could “exten industrial IoT router  d beyond current niche applications,” says Hopkins. The team has already filed for patents on the process.

“The technique introduced here is eloquent in that it uses fundamental surface physics to estimate required oil and membrane properties, and the results demonstrate predicted performance,” says Robert Savinell, a professor of engineering at Case Western Reserve University in Ohio, who was not involved in this research. “This work may indeed mitigate the need for costly high-purity metals and alloys for primary metal-air batteries, and might reduce the complexities of electrolyte additives.”

Savinell adds, “The ability to efficiently extract usable energy from high energy-density aluminum-air batteries, especially under intermittent use conditions, will facilitate the development and improvement of technologies requiring very high energy-densities for extended operation.”

The research was supported by MIT Lincoln Laboratory.

Publication: Brandon J. Hopkins, et al., “Suppressing corrosion in primary aluminum–air batteries via oil displacement,” Science 09 Nov 2018: Vol. 362, Issue 6415, pp. 658-661 DOI: 10.1126/science.aat9149

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How does the human brain recognize faces and distinguish between genuine faces and objects that resemble faces? A new study by Professor Pawan Sinha at MIT and his colleagues indicates that looked at brain activity indicates that both hemispheres are involved in this decision.

Objects that resemble faces are everywhere. Whether it’s New Hampshire’s erstwhile granite “Old Man of the Mountain,” or Jesus’ face on a tortilla, our brains are adept at locating images that look like faces. However, the normal human brain is almost never fooled into thinking such objects actually are human faces.

“You can tell that it has some ‘faceness’ to it, but on the other hand, you’re not misled into believing that it is a genuine face,” says Pawan Sinha, professor of brain and cognitive sciences at MIT.

A new study fro industrial 4G/3G router  m Sinha and his colleagues reveals the brain activity that underlies our ability to make that distinction. On the left side of the brain, the fusiform gyrus — an area long associated with face recognition — carefully calculates how “facelike” an image is. The right fusiform gyrus then appears to use that information to make a quick, categorical decision of whether the object is, indeed, a face.

This distribution of labor is one of the first known examples of the left and right sides of the brain taking on different roles in high-level visual-processing tasks, Sinha says, although hemispheric differences have been seen in other brain functions, most notably language and spatial perception.

Lead author of the paper, published Jan. 4 in the Proceedings of the Royal Society B, is Ming Meng, a former postdoc in Sinha’s lab and now an assistant professor at Dartmouth College. Other authors are Tharian Cherian ’09 and Gaurav Singal, who recently earned an MD from the Harvard-MIT Division of Health Sciences and Technology and is now a resident at Massachusetts General Hospital.

Face versus nonface

Many earlier studies have shown that neurons in the fusiform gyrus, located on the brain’s underside, respond preferentially to faces. Sinha and his students set out to investigate how that brain region decides what is and is not a face, particularly in cases where an object greatly resembles a face.

To help them do that, the researchers created a continuum of images ranging from those that look nothing like faces to genuine faces. They found images that very closely resemble faces by examining photographs that machine vision systems had falsely tagged as faces. Human observers then rated how facelike each of the images were by doing a series of one-to-one comparisons; the results of those comparisons allowed the researchers to rank the images by how much they resembled a face.

The research team then used functional magnetic resonance imaging (fMRI) to scan the brains of research subjects as they categorized the images. Unexpectedly, the scientists found different activity patterns on each side of the b router industrial  rain: On the right side, activation patterns within the fusiform gyrus remained quite consistent for all genuine face images, but changed dramatically for all nonface images, no matter how much they resembled a face. This suggests that the right side of the brain is involved in making the categorical declaration of whether an image is a face or not.

Meanwhile, in the analogous region on the left side of the brain, activity patterns changed gradually as images became more facelike, and there was no clear divide between faces and nonfaces. From this, the researchers concluded that the left side of the brain is ranking images on a scale of how facelike they are, but not assigning them to one category or another.

“From the computational perspective, one speculation one can make is that the left does the initial heavy lifting,” Sinha says. “It tries to determine how facelike is a pattern, without making the final decision on whether I’m going to call it a face.”

Key to the research was imaging-analysis technology that allowed the scientists to look at patterns of activity across the fusiform gyrus.

“This is a relatively recent innovation — looking at the pattern of activation as opposed to overall activation,” says Thomas Busey, associate professor of psychological and brain sciences at Indiana University, who was not involved in this research. “Anytime you have a measure that replicates and correlates with human behavior, that seems to be a pretty compelling story.”

Timing is instructive

The researchers found that activation in the left side of the fusiform gyrus preceded that of the right side by a couple of seconds, supporting the hypothesis that the left side does its job first and then passes information on to the right side.

Sinha says that given the sluggishness of fMRI signals (which rely on blood-flow changes), the timing does not yet constitute definitive evidence, “but it’s a very interesting possibility because it begins to tease apart this monolithic notion of face processing. It’s now beginning to get at what the constituents are of that overall face-processing system.”

The researchers hope to obtain mo inhand network  re solid evidence of temporal relationships between the two hemispheres with studies using electroencephalography (EEG) or magnetoencephalography (MEG), two technologies that offer a much more precise view of the timing of brain activity. They also hope to discover how and when the right and left sides of the fusiform gyrus develop these independent functions by studying blind children who have their sight restored at a young age. Many such children have been treated by Project Prakash, an effort initiated by Sinha to find and treat blind children in India.

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A new study finds ancient Antarctica was much warmer and wetter than previously suspected, with a climate that was suitable to support substantial vegetation—including stunted trees—along the edges of the frozen continent. This artist’s rendition created from a photograph of Antarctica shows what Antarctica possibly looked like during the middle Miocene epoch, based on pollen fossil data. The landscape featured freshwater algae growing in meltwater ponds, low tundra vegetation on coastal plains and tundra with shrub-like southern beech and low podocarp trees growing on warmer sites, with shrubs as high as approximately 20 inches (50 centimeters). Image credit: NASA/JPL-Caltech/Dr. Philip Bart, LSU

In an effort to better understand what the future of climate change may look like, a team of scientists examined plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, finding that ancient Antarctica was much warmer and wetter than previously suspected.

Pasadena, California — A new university-led study with NASA participation finds ancient Antarctica was much warmer and wetter than previously suspected. The climate was suitable to support substantial vegetation — including stunted trees — along the edges of the frozen continent.

The team of scientists involved in the study, published online June 17 in Nature Geoscience, was led by Sarah J. Feakins of the University of Southern California in Los Angeles, and included researchers from NASA’s Jet Propulsion Laboratory in Pasadena, California, and Louisiana State University in Baton Rouge.

By examining plant leaf wax remnants in sediment core samples taken from beneath the Ross Ice Shelf, the research team found summer temperatures along the Antarctic coast 15 to 20 million years ago were 20 degrees Fahrenheit (11 degrees Celsius) warmer than today, with temperatures reaching as high as 45 degrees Fahrenheit (7 degrees Celsius). Precipitation levels also were found to be several times higher than today.

Pollen grains and leaf waxes record vegetation on Antarctica during a time of global warmth 20-15 million years ago, when greenhouse gas concentrations may have been similar to projections for the end of the 21st Century. Image credit: Sophie Warny and Kate Griener (Louisiana State University, Baton Rouge

“The ultimate goal of the study was to better understand what the future of climate change may look like,” said Feakins, an assistant professor of Earth sciences at the USC Dornsife College of Letters, Arts and Sciences. “Just as history has a lot to teach us about the future, so does past climate. This record shows us how much warmer and wetter it can get around the Antarctic ice sheet as the climate system heats up. This is some of the first evidence of just how much warmer it was.”

Scientists began to suspect that high-latitude temperatures during the middle Miocene epoch were warmer than previously believed when co-author Sophie Warny, assistant professor at LSU, discovered large quantities of pollen and algae in sediment cores taken around Antarctica. Fossils of plant life in Antarctica are difficult to come by because the movement of the massive ice sheets covering the landmass grinds and scrapes away the evidence.

Rendering of drilling operations during the ANDRILL campaign in Southern McMurdo Sound, Antarctica, October – December 2007. The successful drilling campaign recovered more than 3,280 feet (1,000 meters) of sediments using new drilling technology on an ice sheet platform. Image credit: University of Nebraska-Lincoln

“Marine sediment cores are ideal to look for clues of past vegetation, as the fossils deposited are protected from ice sheet advances, but these are technically very difficult to acquire in the Antarctic and require international collaboration,” said Warny.

Tipped off by the tiny pollen samples, Feakins opted to look at the remnants of leaf wax taken from sediment cores for clues. Leaf wax acts as a record of climate change by documenting the hydrogen isotope ratios of the water the plant took up while it was alive.

“Ice cores can only go back about one million years,” Feakins said. “Sediment cores allow us to go into ‘deep time.'”

Based upon a model originally developed to analyze hydrogen isotope ratios in atmo router industrial  spheric water vapor data from NASA’s Aura spacecraft, co-author and JPL scientist Jung-Eun Lee created experiments to find out just how much warmer and wetter climate may have been.

“When the planet heats up, the biggest changes are seen toward the poles,” Lee said. “The southward movement of rain bands associated with a warmer climate in the high-latitude southern hemisphere made the margins of Antarctica less like a polar desert, and more like present-day Iceland.”

The peak of this Antarctic greening occurred during the middle Miocene period, between 16.4 and 15.7 million years ago. This was well after the age of the dinosaurs, which became extinct 64 million years ago. During the Miocene epoch, mostly modern-looking animals roamed Earth, such as three-toed horses, deer, camel and various species of apes. Modern humans did not appear until 200,000 years ago.

Warm conditions during the middle Miocene are thought to be associated with carbon dioxide levels of around 400 to 600 parts per million (ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the highest they’ve been in the past several million years. At the current rate of increase, atmospheric carbon dioxide levels are on track to reach middle Miocene levels by the end of this century.

High carbon dioxide levels during the middle Miocene epoch have been documented in other studies through multiple lines of evidence, incPower Fault Detectionluding the number of microscopic pores on the surface of plant leaves and geochemical evidence from soils and marine organisms. While none of these ‘proxies’ is as reliable as the bubbles of gas trapped in ice cores, they are the best evidence available this far back in time. While scientists do not yet know precisely why carbon dioxide was at these levels during the middle Miocene, high carbon dioxide, together with the global warmth documented from many parts of the world and now also from the Antarctic region, appear to coincide during this period in Earth’s history.

This reseaGrid Analytics Systemrch was funded by the U.S. National Science Foundation with additional support from NASA. The California Institute of Technology in Pasadena manages JPL for NASA.

Images: NASA/JPL-Caltech/Dr. Philip Bart, LSU; Sophie Warny and Kate Griener; University of Nebraska-Lincoln

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Engineers from MIT have discovered a way to make “quantum dots” that emit infrared light when injected into the body, providing researchers with highly detailed images of internal body structures. The new research may open up a new way of making detailed images of internal body structures such as fine networks of blood vessels.

For certain frequencies of short-wave infrared light, most biological tissues are nearly as transparent as glass. Now, a team of engineers has made tiny particles that can be injected into the body, where they emit tho Industrial LTE Router  se penetrating frequencies.

The new research is based on the use of light-emitting particles called quantum dots and is described in a paper in the journal Nature Biomedical Engineering. The study is led by MIT research scientist Oliver Bruns.

Near-infrared imaging for research on biological tissues, with wavelengths between 700 and 900 nanometers (billionths of a meter), is widely used, but wavelengths of around 1,000 to 2,000 nanometers have the potential to provide even better results, because body tissues are more transparent to that light. “We knew that this imaging mode would be better” than existing methods, Bruns explains, “but we were lacking high-quality emitters” — that is, light-emitting materials that could produce these precise wavelengths.

Light-emitting particles have been a specialty of Moungi Bawendi, the Lester Wolf Professor of Chemistry, whose lab has over the years developed new ways of making quantum dots. These nanocrystals, made of semiconductor materials, emit light whose frequency can be precisely tuned by controlling the exact size and composition of the particles.

The key was to develop versions of these quantum dots whose emissions matched the desired short-wave infrared frequencies and were bright enough to then be easily detec redundant  ted through the surrounding skin and muscle tissues. The team succeeded in making particles that are “orders of magnitude better than previous materials, and that allow unprecedented detail in biological imaging,” Bruns says. The synthesis of these new particles was initially described in a paper by graduate student Daniel Franke and others from the Bawendi group in Nature Communications last year.

The quantum dots the team produced are so bright that their emissions can be captured with very short exposure times, he says. This makes it possible to produce not just single images but video that captures details of motion, such as the flow of blood, making it possible to distinguish between veins and arteries.

The new light-emitting particles are also the first that are bright enough to allow imaging of internal organs in mice that are awake and moving, as opposed to previous methods that required them to be anesthetized, Bruns says. Initial applications would be for preclinical research in animals, as the compounds contain some materials that are unlikely to be approved for use in humans. The researchers are also working on developing versions that would be safer for humans.

The method also relies on the use of a newly developed camera that is highly sensitive to this particular range of short-wave infrared light. The camera is a commercially developed product, Bruns says, but his team was the first customer for the camera’s specialized detector, made of indium-gallium-arsenide. Though this camera was developed for research purposes, these frequencies of infrared light are also used as a way of seeing through fog or smoke.

Not only can the new method determine the direction of blood flow, Bruns says, it is detailed enough to track individual blood cells within that flow. “We can track the flow in each and every capillary, at super high speed,” he says. “We can get a quantitative measure of flow, and we can do such flow measurements at very high resolution, over large areas.”

Such imaging could Vending Telemetry   potentially be used, for example, to study how the blood flow pattern in a tumor changes as the tumor develops, which might lead to new ways of monitoring disease progression or responsiveness to a drug treatment. “This could give a good indication of how treatments are working that was not possible before,” he says.

“This is an exciting and potentially revolutionary development for small animal imaging,” says Guillermo Tearney, a professor of pathology at Harvard Medical School, who was not involved in this work. “By using probes that are tuned to wavelengths further out in the short-wave near-infrared, the investigators overcome scattering, which is the major phenomenon” limiting such in vivo microscopy, he says.

“In so doing, simpler and less invasive interrogation methods can be utilized to understand structure and function in animal models, on both the organ and cellular level,” Tearney says. “I anticipate that these probes will have a major impact on the field of intravital [done with living subjects] imaging and bioscience research.”

Publication: Oliver T. Burns, et al., “Next-generation in vivo optical imaging with short-wave infrared quantum dots,” Nature Biomedical Engineering 1, Article number: 0056 (2017) doi:10.1038/s41551-017-0056

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Neutron scattering studies of lattice excitations in a fresnoite crystal revealed a way to speed thermal conduction. Oak Ridge National Laboratory, US Dept. of Energy; graphic artist Jill Hemman

Researchers at the Department of Energy’s Oak Ridge National Laboratory made the first observations of waves of atomic rearrangements, known as phasons, propagating supersonically through a vibrating crystal lattice–a discovery that may dramatically improve heat transport in insulators and enable new strategies for heat management in future electronics devices.

“The discovery gives you a different way to control the flow of heat,” said lead author Michael Manley of the paper published in Nature Communications. “It provides a shortcut through the material–a way to send the energy of pure atomic motion at a speed that’s higher than you can with phonons [atomic vibrations]. This shortcut may open possibilities in heat management of nanoscale materials. Imagine the possibility of a thermal circuit breaker, for example.”

The scientists used neutron scattering to measure phasons with velocities about 2.8 times and about 4.3 times faster than the natural “speed limits” of longitudinal and transverse acoustic waves, respectively. “We didn’t expect them to be going that fast without [fading],” Manley said.

Insulators are necessary in electronic devices to prevent short circuits; but without free electrons, thermal transport is limited to the energy of atomic motion. Hence, understanding the transport of heat by atomic motion in insulators is important.

The researchers scattered neutrons in fresnoite, a crystalline mineral so named because it was first found in Fresno, California. It is promising for sensor applications through its piezoelectric property, which allows it to turn mechanical stress into electrical fields.

Fresnoite has a flexible framework structure that develops a competing order in the structure that does not match the underlying crystal order, like an overlay of mismatched tiles. Phasons are excitations associated with atomic rearrangements in the crystal that change the phase of waves describing the mismatch in the structure.

Phase differences accumulat router  e in a lattice of wrinkl industrial wireless router es–called solitons. Solitons are solitary waves that propagate with little loss of energy and retain their shape. They can also warp the local environment in a way that allows them to travel faster than sound.

“The soliton is a very deformed region in the crystal where the displacements of the atoms are large and the force-displacement relationship is no longer linear,” Manley said. “The material stiffness is locally enhanced within the soliton, leading to a faster energy transfer.”

Raffi Sahul of Meggitt Sensing Systems of Irvine, California, grew a single crystal of fresnoite and sent it to ORNL for neutron scattering experiments that Manley conceived to characterize how energy moved through the crystal. “Neutrons are the best way to study this because their wavelengths and energies are in a sense matched to the atomic vibrations,” Manley said.

Manley performed measurements with Paul Stonaha, Doug Abernathy and John Budai using time-of-flight neutron scattering at the Spallation Neutron Source, and with Stonaha, Songxue Chi, and Raphael Hermann using triple-axis neutron scattering at the High Flux Isotope Reactor.

At SNS, the scientists started with a pulsed source of neutrons of different energies and used the ARCS instrument, which selects neutrons in a narrow energy range and scatters them off a sample so detectors can map the energy and momentum transfer over a wide range.

“The large measurement area was important to this study because the features weren’t where you would normally expect them to be,” said Abernathy. “This gives the neutron measurements a great chance to determine the velocities of the propagating phasons, calculated from the slope of their dispersion curves.”

Dispersion is the relationship between the wavelength and the energy that characterizes a propagating wave.

“Once the SNS measurements told us where to look, we used triple-axis spectrometry at HFIR, which provided a constant flux of neutrons, to focus on that one point,” Manley said. “A unique thing about Oak Ridge National Laboratory is that we have both a world-class spallation source and a world-class reactor source for neutron research. We can go back and forth between facilities and really get a comprehensive view of things.”

Next the researchers will explore other crystals that, like fresnoite, can rotate phasons. Strain applied with an electric field may be able to change the rotation. Changes in temperature may vary properties too.

Pu low-cost M2M router blication: M. E. Manley, et al., “Supersonic propagation of lattice energy by phasons in fresnoite,” Nature Communications, volume 9, Article number: 1823 (2018) doi:10.1038/s41467-018-04229-1

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Lake Tahoe is renowned for its intense blue hue. Credits: Wikimedia Commons

New research from UC Davis and NASA reveals that the blueness of Lake Tahoe is controlled by algal concentration, which in turn is driven by the level of nutrients available to the algae.

Lake Tahoe’s iconic blueness is most strongly related to algae, not clarity, according to research released today from the UC Davis Tahoe Environmental Research Center, telemeter   or TERC. In the “Tahoe: State of the Lake Report 2015,” researchers found the lower the algal concentration, the bluer the lake.

The report also includes updates related to clarity, climate change, drought and new research at Lake Tahoe.

Clear and blue

The assumption that lake clarity is tied to blueness has driven advocacy and management efforts in the Lake Tahoe Basin for decades. But the report’s findings show that at times of the year when clarity increases, blueness decreases, and vice versa. This is due to the seasonal interplay of sediment, nutrients and algal production as the lake mixes.

Clarity is controlled by sediment. Blueness is controlled by algal concentration, which in turn is driven by the level of nutrients available to the algae.

“This is good news,” said Geoffrey Schladow, director of the UC Davis Tahoe Environmental Research Center and a civil engineering professor. “It shows that we better understand how Lake Tahoe works, and it reinforces the importance of controlling nutrient inputs to the lake, whether from the forest, the surrounding lawns or even from the air. It’s particularly encouraging that blueness has been increasing over the last three years.”

Low precipitation helped keep runoff from both nutrients and sediment low in 2014.

Blueness Index

Shohei Watanabe, a postdoctoral researcher at UC Davis TERC, led the blueness study in collaboration with NASA-Jet Propulsion Laboratory and Laval University. He produced a Blueness Index, quantifying Lake Tahoe’s color for the first time by using data from a NASA-JPL research buoy at the lake and hyperspectral radiometers that measure the amount of light leaving the lake at each waveband — in other words, its color.

Watanabe combined the Blueness Index with TERC measurements of Secchi depth — the depth at which a white disk remains visible when lowered into the water. He was surprised to see that blueness and clarity did not correspond. In fact, they varied in opposite directions.

“This does not mean that clarity should be dismissed,” said Watanabe. “Rather, it shows that algae concentrations and nutrient input should be managed more closely to truly keep Tahoe blue and clear.”

The JPL buoy u distribution automation  sed in the study is one of four established by NASA with support from TERC to calibrate and validate measurements taken by satellites flying overhead.

“This particular buoy has instruments beneath the water looking up, and an instrument on the buoy looking down,” said JPL’s 4g LTE router with SIM cardSimon Hook, who collaborated with Watanabe. “The combination of instruments in and above the water are used in this study to look at how light is being scattered and attenuated. That tells you something about both the color and the clarity of the lake.”

A record-breaking year

Other highlights from the State of the Lake Report include:

Clarity: Average annual water clarity was the best in more than a decade, improving from 70.2 feet in 2013 to 77.8 feet in 2014. The improvements were influenced, in part, by the drought: With little rain, fewer contaminants washed into the lake. Climate change: Warm, dry conditions continued for the third straight year in 2014. The average annual minimum and maximum air temperatures at Tahoe City were the highest recorded since 1910. Precipitation was only 61 percent of average, with only 18 percent of it falling as snow, well below normal. April snowpack in the Tahoe Basin was the lowest recorded in 100 years of record keeping. Evaporation: The largest water loss from Lake Tahoe is from evaporation. In 2014, 52 inches of water evaporated from the lake. One inch of evaporation is equal to 3.5 billion gallons of water. Lake level fell below the natural rim on Oct. 16, 2014, stopping the outflow of Lake Tahoe water to the Truckee River. By the end of 2014, the final lake level was a half-foot below the rim. Lake temperature: Annual average surface temperatures reached an all-time high of 53 F, and winter experienced that season’s warmest surface water temperature in the lake’s recorded history. Mixing. Lake Tahoe did not mix to its full depth for the third consecutive year, due to warmer water and record-high levels of lake stability (resistance to mixing). This lack of deep mixing also led to the highest nitrate-nitrogen levels on record, 20 micrograms per liter. Biology: Attached algae around the margins of the lake were at record-low values, largely due to the very low lake level.

The State of the Lake report informs nonscientists about the most important factors affecting lake health and helps influence decisions about ecosystem restoration and management within the Lake Tahoe Basin.

The 2015 State of the Lake report was funded by the California Tahoe Conservancy, IVGID Waste Not Program, League to Save Lake Tahoe, Parasol Tahoe Community Foundation, Tahoe Area Sierra Club, Tahoe Fund, Tahoe Lakefront Owners Association, Tahoe Regional Planning Agency, Tahoe Water Suppliers Association, Toiyabe Chapter of the Sierra Club, and the generosity of supporters who value the role of science to save the lake. TERC partners with other research institutions and with resource agencies in the Tahoe Basin to address the current challenges facing Lake Tahoe.