Post Syndicated from Mark Anderson original https://spectrum.ieee.org/energywise/energy/environment/a-very-close-look-at-carbon-capture-and-storage
A material called ZIF-8 swells up when carbon dioxide molecules are trapped inside, new images reveal
A new kind of molecular-scale microscope has been trained for the first time on a promising wonder material for carbon capture and storage. The results, researchers say, suggest a few tweaks to this material could further enhance its ability to scrub greenhouse gases from emissions produced by traditional power plants.
The announcement comes in the wake of a separate study concerning carbon capture published in the journal Nature. The researchers involved in that study found that keeping the average global temperature change to below 1.5 degrees C (the goal of the Paris climate accords) may require more aggressive action than previously anticipated. It will not be enough, they calculated, to stop building new greenhouse-gas-emitting power stations and allow existing plants to age out of existence. Some existing plants will also need to be shuttered or retrofitted with carbon capture and sequestration technology.
Post Syndicated from Amy Nordrum original https://spectrum.ieee.org/tech-talk/energy/environment/an-oftstruck-mountaintop-tower-gets-a-new-lightning-sensor
Säntis Tower in the Swiss Alps is struck by lightning more than 100 times a year
Atop a rocky peak in the Swiss Alps sits a telecommunications tower that gets struck by lightning more than 100 times a year, making it perhaps the world’s most frequently struck object. Taking note of the remarkable consistency with which lightning hits this 124-meter structure, researchers have adorned it with instruments for a front-row view of these violent electric discharges.
On Wednesday, a small team installed a new gadget near Säntis Tower in their years-long quest to better understand how lightning forms and why it behaves the way it does. About two kilometers from the tower, they set up a broadband interferometer that one member, Mark Stanley of New Mexico Tech, had built back in his lab near Jemez, New Mexico.
“You can’t really go to a company and find an instrument that’s built just for studying lightning,” says Bill Rison, Stanley’s collaborator who teaches electrical engineering at New Mexico Tech. “You have to build your own.”
The one Stanley built has three antennas with bandwidth from 20 to 80 megahertz (MHz) to record powerful electromagnetic pulses in the very high-frequency range that lightning is known to produce. The device also has a fourth antenna to measure sferics, which are low-frequency signals that result from the movement of charge that occurs with a strike or from storm activity within clouds. “Basically, lightning is a giant spark,” Rison explains. “Sparks give off radio waves and the interferometer detects the radio waves.”
To anyone who has witnessed a lightning strike, everything seems to happen all at once. But Stanley’s sensor captures several gigabytes of data about the many separate pulses that occur within each flash. Those data can be made into a video that replays, microsecond by microsecond, how “channels” of lightning form in the clouds.
By mapping lightning in this way, the Säntis team, which hired Stanley and Rison to haul their interferometer to Switzerland, hopes to better understand what prompts lightning’s “initiation”—that mysterious moment when it cracks into existence.
So far, measurements have raised more questions than they’ve answered. One sticking point is, in order for a thunderstorm to emit a lightning strike, the electric field within it must build to an intensity on the order of several megavolts per meter. But while researchers have sent balloons into thunderstorms, no one has measured a field beyond 200 kilovolts per meter, or one-tenth of the required value, says Farhad Rachidi of the Swiss Federal Institute of Technology (EPFL), who co-leads the Säntis research team.
“The conditions required for lightning to be started within the clouds never seem to exist based on the measurements made in the clouds,” says Marcos Rubinstein, a telecommunications professor at Switzerland’s School of Business and Engineering Vaud and co-leader of the Säntis team with Rachidi. “This is a big, big question.”
In his own research at New Mexico Tech, Rison has laid some groundwork that could explain how small electric fields can produce such big sparks. In 2016, he and his colleagues published a paper in Nature Communications that described experimental evidence showing that a process known as fast positive breakdown can create a series of streamers, or tiny sparks, and may arise from much stronger local electric fields that occur in small pockets within a storm.
If enough streamers occur in quick succession and within close vicinity to one another, they make more streamers, adding up to a streamer “avalanche” that turns into positive leaders, or mini-bolts that branch toward clouds or the ground.
“We haven’t hit any roadblocks yet to say, this is something that isn’t the process for the initiation of lightning,” Rison says. With his evidence in hand, theorists are now trying to explain exactly how and why these fast positive breakdowns occur in the first place.
Meanwhile, the Säntis team wants to adapt a mathematical technique called time-reversal, which was originally pioneered for acoustics, to better understand lightning’s initiation. With this method, they intend to use data gathered by the tower’s many instruments (which include a collection of six antennas called a lightning mapping array, two Rogowski coils to measure current, two B-Dot sensors to measure the current time-derivative, broadband electric and magnetic field sensors, and a high-speed camera) to reconstruct the total path of strikes soon after they happen, tracing the electromagnetic radiation all the way back to its original source.
As has been true of past lightning research, their findings may someday inform the design of airplanes or electric grids, and help protect people and equipment against lightning strikes and other sudden power surges. The Säntis team’s work has held particular relevance for wind farm operators. That’s because most strikes recorded at the tower are examples of upward lightning—which travels from ground-to-cloud instead of cloud-to-ground.
Upward lightning often originates from tall buildings and structures, which can actually create a lightning bolt that shoots skyward, and this process can damage wind turbines. In 2013, the team published one of the most extensive descriptions to date of this type of flash.
More recently, their work has raised questions about why industry safety certifications for aircraft are based on data about downward strikes, instead of upward ones, which commonly occur with aircraft and cause particular kinds of damage that look more like lightning damage reported by pilots and mechanics.
By the end of this year, the Säntis team expects to record its 1,000th lightning strike at the tower. And there’s one more elusive scientific matter with massive practical implications they hope to someday resolve. “If we understand how lightning is initiated, we could take a big step forward on one of the other questions we’ve been trying to solve for a long time, and that’s to be able to predict lightning before it happens,” says Rubinstein.
Post Syndicated from IEEE Spectrum Recent Content full text original https://spectrum.ieee.org/whitepaper/do-you-know-your-oscilloscopes-signal-integrity
Ebook: How to Determine Oscilloscope Signal Integrity
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Post Syndicated from Mark Anderson original https://spectrum.ieee.org/energywise/energy/environment/a-glass-battery-that-keeps-getting-better
A prototype solid-state battery based on lithium and glass faces criticism over claims that its capacity increases over time
Is there such a thing as a battery whose capacity to store energy increases with age? One respected team of researchers say they have developed just such a technology. Controversy surrounds their claims, however, in part because thermodynamics might seem to demand that a battery only deteriorates over many charge-discharge cycles.
The researchers have a response for that critique and continue to publish peer-reviewed papers about this work. If such claims came from almost any other lab, they might be ignored and shunned by the broader community of battery researchers, the same way physicists turn their noses up at anything that smacks of a perpetual motion machine.
But this lab belongs to one of the most celebrated battery pioneers today—and one of the inventors of the lithium-ion battery itself. John Goodenough, who at 96 continues to research and publish like scientists one-third his age, last year joined with three co-authors in publishing a paper that grabbed headlines. (Spectrum had profiled him and his battery technology the year before, following an initial announcement about his group’s new glass battery.)
Post Syndicated from John Boyd original https://spectrum.ieee.org/tech-talk/energy/environment/how-to-keep-a-close-eye-on-australias-great-barrier-reef
An Australian research team is using tech to monitor global climate change’s assault on the world’s largest living organism
The stats are daunting. The Great Barrier Reef is 2,300 kilometers long, comprises 2,900 individual coral reefs, and covers an area greater than 344,000 square kilometers, making it the world’s largest living organism and a UNESCO World Heritage Site.
A team of researchers from Queensland University of Technology (QUT) in Brisbane, is monitoring the reef, located off the coast of northeastern Australia, for signs of degradation such as the bleaching caused by a variety of environmental pressures including industrial activity and global warming.
The team, led by Felipe Gonzalez, an associate professor at QUT, is collaborating with the Australian Institute of Marine Science (AIMS), an organization that has been monitoring the health of the reef for many years. AIMS employs aircraft, in-water surveys, and NASA satellite imagery to collect data on a particular reef’s condition. But these methods have drawbacks, including the relatively low resolution of satellite images and high cost of operating fixed-wing aircraft and helicopters.
So Gonzalez is using an off-the-shelf drone modified to carry both a high-resolution digital camera and a hyperspectral camera. The monitoring is conducted from a boat patrolling the waters 15 to 70 km from the coast. The drone flies 60 meters above the reef, and the hyperspectral camera captures reef data up to three meters below the water’s surface. This has greatly expanded the area of coverage and is helping to verify AIMS’s findings.
The digital camera is used to build up a conventional 3D model of an individual reef under study, explains Gonzalez. But this conventional camera is capable of capturing light only from three spectral channels: the red, green, and blue covering the 380-to-740-nanometer portion of the electromagnetic spectrum. The hyperspectral camera, by contrast, collects the reflected light of 270 spectral bands.
“Hyperspectral imaging greatly improves our ability to monitor the reef’s condition based on its spectral properties,” says Gonzalez. “That’s because each component making up a reef’s environment—water, sand, algae, etc.—has its own spectral signature, as do bleached and unbleached coral.”
But this expansion in reef coverage and richness of gathered data presented the team with a new challenge. Whereas AIMS divers can gather information on 40 distinct points on a reef in an underwater session, just one hyperspectral image presents more than 4,000 data points. Consequently, a single drone flight can amass a thousand gigabytes of raw data that has to be processed and analyzed.
In processing the data initially, the team used a PC, custom software tools, and QUT’s high-performance computer, a process that took weeks and drew heavily on the machine’s run time.
So the team applied for and received a Microsoft AI for Earth grant, which makes software tools, cloud computing services, and AI deep learning resources available to researchers working on global environmental challenges.
“Now we can use Microsoft’s AI tools in the cloud to supplement our own tools and quickly label the different spectral signatures,” says Gonzalez. “So, where processing previous drone sweeps used to take three or four weeks, depending on the data, it now takes two or three days.”
This speedup in data processing is critical. If it took a year or more before the team were able to tell AIMS that a certain part of the reef is degrading rapidly, it might be too late to save it.
“And by being informed early, the government can then take quicker action to protect an endangered area of the reef,” Gonzalez adds.
He notes that the use of hyperspectral imaging is now a growing area of remote sensing in a variety of fields, including agriculture, mineral surveying, mapping, and location of water resources.
For example, he and colleagues at QUT are also using the technology to monitor forests, wheat crops, and vineyards that can be affected by pathogens, fungi, or aphids.
Meanwhile, over the next two months, Gonzalez will continue processing the spectral data collected from the reef so far; and then in September, he will start a second round of drone flights.
“We aim to return to the four reefs AIMS has already studied to monitor any changes,” he says, “then extend the monitoring to new reefs.”