. Scientific Frontline

Monday, December 6, 2021

Sodium-based Material Yields Stable Alternative to Lithium-ion Batteries

Scientists at the University of Texas at Austin have developed a new sodium metal anode for rechargeable batteries (left) that resists the formation of dendrites, a common problem with standard sodium metal anodes (right) that can lead to shorting and fires. Images were taken with a scanning electron microscope.
Image credit: Yixian Wang/University of Texas at Austin.

University of Texas at Austin researchers have created a new sodium-based battery material that is highly stable, capable of recharging as quickly as a traditional lithium-ion battery and able to pave the way toward delivering more energy than current battery technologies.

For about a decade, scientists and engineers have been developing sodium batteries, which replace both lithium and cobalt used in current lithium-ion batteries with cheaper, more environmentally friendly sodium. Unfortunately, in earlier sodium batteries, a component called the anode would tend to grow needle-like filaments called dendrites that can cause the battery to electrically short and even catch fire or explode.

Migratory birds have lighter-colored feathers

As a result, the plumage absorbs less solar energy and thus prevents overheating during long flights

Migratory birds are specially adapted to find their way over extreme distances that represent remarkable tests of endurance. Now, researchers of the Max Planck Institute for Ornithology in Seewiesen and colleagues have discovered an unexpected way that migratory birds keep their cool during such arduous journeys: lighter-colored feathers.

"We found across nearly all species of birds, migratory species tend to be lighter colored than non-migratory species,” said Kaspar Delhey of the Max Planck Institute for Ornithology, Seewiesen, Germany. “We think that lighter plumage coloration is selected in migratory species because it reduces the risk of overheating when exposed to sunshine. Lighter surfaces absorb less heat than darker ones, as anybody wearing dark clothes on a sunny day can attest! This would be particularly important for long-distance migrants that undertake extensive flights during which they cannot stop to rest in the shade.”

Delhey and colleagues had been studying the effects of climate on bird coloration. Their earlier studies showed that, in general, lighter colored birds are found where temperatures are high and there is little shade. Presumably that’s at least in part because the birds’ lighter plumage helps to keep them cooler in the hot sun. Around that same time, the researchers came across studies by others showing that some birds fly at much higher altitudes during the day compared to at night.

Trees are biggest methane 'vents' in wetland areas – even when they're dry

Image credit: Viviane Figueiredo Souza
Most of the methane gas emitted from Amazon wetlands regions is vented into the atmosphere via tree root systems – with significant emissions occurring even when the ground is not flooded, say researchers at the University of Birmingham.

In a study published in the Royal Society journal, Philosophical Transactions A, the researchers have found evidence that far more methane is emitted by trees growing on floodplains in the Amazon basin than by soil or surface water and this occurs in both wet and dry conditions.

Methane is the second most important greenhouse gas and much of our atmospheric methane comes from wetlands. A great deal of research is being carried on into exactly how much methane is emitted via this route, but models typically assume that the gas is only produced when the ground is completely flooded and underwater.

In wetland areas where there are no trees, methane would typically be consumed by the soil on its way to the surface, but in forested wetland areas, the researchers say the tree roots could be acting as a transport system for the gas, up to the surface where it vents into the atmosphere from the tree trunks.

Methane is able to escape via this route even when it is produced in soil and water that is several meters below ground level.

This would mean that existing models could be significantly underestimating the likely extent of methane emissions in wetland areas such as the Amazon basin.

Thursday, December 2, 2021

Color-changing magnifying glass gives clear view of infrared light

Nano-antennas convert invisible infrared into visible light 
Credit: NanoPhotonics Cambridge/Ermanno Miele, Jeremy Baumberg
Detecting light beyond the visible red range of our eyes is hard to do, because infrared light carries so little energy compared to ambient heat at room temperature. This obscures infrared light unless specialized detectors are chilled to very low temperatures, which is both expensive and energy-intensive.

Now researchers led by the University of Cambridge have demonstrated a new concept in detecting infrared light, showing how to convert it into visible light, which is easily detected.

In collaboration with colleagues from the UK, Spain and Belgium, the team used a single layer of molecules to absorb the mid-infrared light inside their vibrating chemical bonds. These shaking molecules can donate their energy to visible light that they encounter, ‘upconverting’ it to emissions closer to the blue end of the spectrum, which can then be detected by modern visible-light cameras.

The results, reported in the journal Science, open up new low-cost ways to sense contaminants, track cancers, check gas mixtures, and remotely sense the outer universe.

The challenge faced by the researchers was to make sure the quaking molecules met the visible light quickly enough. “This meant we had to trap light really tightly around the molecules, by squeezing it into crevices surrounded by gold,” said first author Angelos Xomalis from Cambridge’s Cavendish Laboratory.

Researchers engineer magnetic complexity into atomically thin magnets

Layering two bilayer flakes of chromium triiodide
 and twisting them a tiny amount offsets the chromium atoms
within the material and creates a more complex magnetic moment.
Image credit: Zhao Lab, University of Michigan

Magnets are used in so many of our everyday objects including cell phones and in the strip of a credit card or a hotel key. They even power the engine in your vacuum.

And as most computers use magnets to store information, finding ever thinner magnets is key to faster, lighter electronics. Graphene, a material that is one atom thick, was discovered in 2004 and won the 2010 Nobel Prize in physics. While graphene is not magnetic itself, it triggered the interest of searching for atomically thin magnets.

In 2017, scientists found an ultrathin, magnetic material just three atoms, or one atomic unit, thick. But this material, called chromium triiodide, had a simple magnetic moment arrangement—the spin of the electrons within the material all aligned in the same direction, either up or down—which means it’s not able to store large amounts of information.

Now, University of Michigan physicist Liuyan Zhao and her team have developed a way to create a more complex magnetic moment arrangement in chromium triiodide, allowing this atomically thin material to store more information and to perhaps process information faster. Their results are published in Nature Physics.

“Over time, people began looking for smaller sizes and more complex forms of magnets in order to make our computers and electronics smaller, thinner and faster. To do this, the material that stores data or does information processing needs to also get smaller and smaller, while their magnetic forms should be more and more exotic,” Zhao said. “In very big, bulky materials, people find all kinds of magnetic forms called spin textures. So in this ultrathin material, we asked: Can we also create those kinds of complex spin textures so that we can store more information?”

To do this, Zhao and her team created an artificial sample by tearing a micron-sized (one millionth of a meter) flake of chromium triiodide into two. The flake of chromium triiodide is bilayer, which means the material is two atomic units, or six atoms, thick. Then, they layered one piece on top of the other and rotated it a tiny amount. Each flake is composed of a crystalline lattice structure, and when one structure is laid over another and rotated a small amount, the crystalline structures interfere with each other and form a periodic structure with a longer wavelength. This also creates an angular mismatch between the two flakes and leads to a superlattice with a longer period called a moiré superlattice.

Nanoracks, Voyager Space, And Lockheed Martin Awarded NASA Contract To Build First-Of-Its-Kind Commercial Space Station

Nanoracks, Voyager Space, and Lockheed Martin Awarded NASA Contract to Build First-of-its-Kind Commercial Space Station

Starlab to anchor NASA’s Commercial Low-Earth Orbit Destinations project as the space economy continues to grow

Nanoracks, in collaboration with Voyager Space and Lockheed Martin [NYSE: LMT], has been awarded a $160 million contract by NASA to design its Starlab commercial space station as part of the agency’s Commercial Low-Earth Orbit (LEO) Development program. Starlab will enable NASA’s initiative to stimulate the commercial space economy and provide science and crew capabilities prior to the retirement of the International Space Station (ISS).

“While today marks a major milestone for Nanoracks and our Starlab team, the impact goes far beyond this award,” said Dr. Amela Wilson, CEO at Nanoracks. “To receive this support from NASA validates over a decade of Nanoracks’ hard work forging commercial access to space, bringing over 1300 commercial payloads from 30 nations to the ISS. This opportunity opens far-reaching possibilities for critical research and commercial industrial activity in LEO. We are honored to be selected as one of three awardees to work with NASA, and we cannot wait to bring our existing global commercial customer base to Starlab.”

TESS discovers a planet the size of Mars but with the makeup of Mercury

Caption:An illustration of a red dwarf star orbited by an exoplanet.
Credits: NASA/ESA/G. Bacon (STScI)

Ultra-short-period planets are small, compact worlds that whip around their stars at close range, completing an orbit — and a single, scorching year — in less than 24 hours. How these planets came to be in such extreme configurations is one of the continuing mysteries of exoplanetary science.

Now, astronomers have discovered an ultra-short-period planet (USP) that is also super light. The planet is named GJ 367 b, and it orbits its star in just eight hours. The planet is about the size of Mars, and half as massive as the Earth, making it one of the lightest planets discovered to date.

Orbiting a nearby star that is 31 light years from our own sun, GJ 367 b is close enough that researchers could pin down properties of the planet that were not possible with previously detected USPs. For instance, the team determined that GJ 376 b is a rocky planet and likely contains a solid core of iron and nickel, similar to Mercury’s interior.

Due to its extreme proximity to its star, the astronomers estimate GJ 376 b is blasted with 500 times more radiation than what the Earth receives from the sun. As a result, the planet’s dayside boils at up to 1,500 degrees Celsius. Under such extreme temperatures, any substantial atmosphere would have long vaporized away, along with any signs of life, at least as we know it.

Stem cell-based treatment produces insulin in patients with Type 1 diabetes

Sentinel device in the Kieffer Lab.
In the first study of its kind, a team of researchers at the University of British Columbia’s faculty of medicine and Vancouver Coastal Health (VCH) has helped to demonstrate that a stem cell-based treatment delivered through an implantable device can produce insulin in the human body.

The treatment was provided to B.C. patients living with a severe form of Type 1 diabetes as part of a multi-year clinical trial. The study results were published today in Cell Stem Cell.

“Our findings demonstrate the incredible potential of this stem cell-based treatment. With further research, this treatment could one day eliminate dependence on insulin injections and transform the management of Type 1 diabetes,” said the study’s senior author Dr. Timothy Kieffer, professor in UBC faculty of medicine’s departments of surgery and cellular and physiological sciences, who was recently appointed as ViaCyte’s chief scientific officer.

At the start of the UBC-VCH study, 15 patients underwent surgery at Vancouver General Hospital, where several cell-containing devices developed by California-based biotechnology company ViaCyte were implanted just below the skin. Each device—about seven centimeters long and no thicker than a credit card—contained millions of lab-grown cells that originally came from a single stem cell line and were ‘coached’ into maturing into beta cells. Beta cells are responsible for making insulin, the hormone that controls a person’s blood sugar.

Volcanic eruptions drove severe mass extinction, say scientists

Abrupt climate change ~450-440 million years ago caused the demise of the trilobite, Selenopeltis (pictured, in Oxford University Museum of Natural History).
Photograph: Dr Tom Gernon

Two intense periods of volcanism triggered a period of global cooling which caused one of the most severe mass extinctions in Earth history, according to new research.

The study, published in Nature Geoscience, was conducted by scientists at the University of Plymouth, the University of Oldenburg, the University of Southampton and the University of Leeds.

They examined the effects of volcanism on ocean chemistry during a period of extreme environmental change around 450 million years ago.

This period brought about intense planetary cooling, which culminated in a glaciation and the major ‘Late Ordovician Mass Extinction’. It led to the loss of about 85% of species dwelling in the oceans, reshaping the course of evolution of life on Earth.

Through their research, the team identified that two exceptionally large pulses of volcanic activity across the globe – occurring in parts of present-day North America and South China – coincided very closely with two peaks in glaciation and extinction separated by about 10 million years.

New testing method yields pathway to better, longer-lasting batteries

This illustration shows how a team at Sandia National Laboratories used Kelvin probe force microscopy to locate places where electron flows get stuck, potentially leading to engineering longer-lasting, more efficient batteries.
Illustration courtesy of S. Kelley/National Institute of Standards and Technology.
Using a microscopic method for measuring electrical potential, a team of scientists at Sandia National Laboratories may have discovered how to make a longer-lasting, more efficient battery.

The team of Elliot Fuller, Josh Sugar and Alec Talin detailed their findings in an article published in American Chemical Society Energy Letters.

“One of the challenges with solid-state batteries is that at the boundaries between different parts of the battery — a cathode and a layer of ion-conducting electrolyte, let’s say — something interferes with the flow of electrons,” Talin said.

Solid-state batteries employ solid electrolytes instead of electrochemical gels and liquids and generally power small electronics. Most researchers suspected that there was a loss of voltage or electrical potential at interfaces within the battery, but not which interface was responsible for most of the impedance in the battery. The team started work five years ago to get some clarity.

“There were two main motivations for this. The first was fundamental: we want to have good models for batteries that we can use to develop better materials,” Talin explained. “The second thing was to figure out how we can engineer the interfaces to make them less impeding. In our case, it really has to do a lot with how fast lithium ions can move in the Si anode used in the study.”

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