Lithium-ion batteries without fire risk developed

Agencies
August 23, 2018

Washington, Aug 23: Scientists have developed novel lithium-ion batteries with components that harden on impact, preventing them from catching fire and causing injuries to users.

Lithium-ion batteries commonly used in consumer electronics are notorious for bursting into flame when damaged or improperly packaged.

These incidents occasionally have grave consequences, including burns, house fires and at least one plane crash. Inspired by the property of some liquids that solidify on impact, researchers have developed a practical and inexpensive way to help prevent these fires.

"In a lithium-ion battery, a thin piece of plastic separates the two electrodes," said Gabriel Veith, from US Department of Energy's (DOE) Oak Ridge National Laboratory.

"If the battery is damaged and the plastic layer fails, the electrodes can come into contact and cause the battery’s liquid electrolyte to catch fire," said Veith.

To make these batteries safer, some researchers instead use a nonflammable, solid electrolyte. However, these solid-state batteries require significant retooling of the current production process, Veith said.

As an alternative, the team mixes an additive into the conventional electrolyte to create an impact-resistant electrolyte.

It solidifies when hit, preventing the electrodes from touching if the battery is damaged during a fall or crash. If the electrodes don't touch each other, the battery doesn't catch fire.

One of Veith's major advances involves the production process for the batteries. During manufacture of traditional lithium-ion batteries, an electrolyte is squirted into the battery case at the end of the production process, and then the battery is sealed.

"You can;t do that with a shear-thickening electrolyte because the minute you try to inject it, it solidifies," he said.

The researchers solved this by putting the silica in place before adding the electrolyte. They are seeking a patent on their technique.

In the future, Veith plans to enhance the system so the part of the battery that's damaged in a crash would remain solid, while the rest of the battery would go on working.

The team is initially aiming for applications such as drone batteries, but they would eventually like to enter the automotive market. They also plan to make a bigger version of the battery, which would be capable of stopping a bullet.

That could benefit soldiers, who often carry 20 pounds of body armor and 20 pounds of batteries when they are on a mission, Veith said.

"The battery would function as their armour, and that would lighten the average soldier by about 20 pounds," he said.

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Agencies
February 29,2020

Ahmedabad, Feb 29: The presence of two feral pigeons onboard a GoAir flight at the airport in Ahmedabad in Gujarat created a flutter among the amused passengers, even though the avian surprise did not lead to any untoward incident or delay in the flight.

The incident took place on Friday when the passengers were boarding the Ahmedabad-Jaipur flight.

"Two pigeons had found their way inside the flight G8 702 while the passengers were boarding," an airline statement said on Saturday.

"The crew immediately shooed away the birds. The flight took off at its scheduled time at 5 p.m.," it added.

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Agencies
July 2,2020

Leiden, Jul 2: Astronomers have discovered a luminous galaxy caught in the act of reionizing its surrounding gas only 800 million years after the Big Bang.

The research, led by Romain Meyer, PhD student at UCL in London, UK, has been presented at the virtual annual meeting of the European Astronomical Society (EAS).

Studying the first galaxies that formed 13 billion years ago is essential to understanding our cosmic origins. One of the current hot topics in extragalactic astronomy is 'cosmic reionization,' the process in which the intergalactic gas was ionized (atoms stripped of their electrons).

Cosmic reionization is similar to an unsolved murder: We have clear evidence for it, but who did it, how and when? We now have strong evidence that hydrogen reionization was completed about 13 billion years ago, in the first billion years of the universe, with bubbles of ionized gas slowly growing and overlapping.

The objects capable of creating such ionized hydrogen bubbles have however remained mysterious until now: the discovery of a luminous galaxy in which 60-100 percent of ionizing photons escape, is likely responsible for ionizing its local bubble. This suggests the case is closer to being solved.

The two main suspects for cosmic reionization are usually 1) a population of numerous faint galaxies leaking ~10 percent of their energetic photons, and 2) an 'oligarchy' of luminous galaxies with a much larger percentage (>50 percent) of photons escaping each galaxy.

In either case, these first galaxies were very different from those today: galaxies in the local universe are very inefficient leakers, with only <2-3 percent of ionizing photons escaping their host. To understand which galaxies governed cosmic reionization, astronomers must measure the so-called escape fractions of galaxies in the reionization era.

The detection of light from excited hydrogen atoms (the so-called Lyman-alpha line) can be used to infer the fraction of escaping photons. On the one hand, such detections are rare because reionization-era galaxies are surrounded by neutral gas which absorbs that signature hydrogen emission.

On the other hand, if this hydrogen signal is detected it represents a 'smoking gun' for a large ionized bubble, meaning we have caught a galaxy reionizing its surroundings. The size of the bubble and the galaxy's luminosity determines whether it is solely responsible for creating this ionized bubble or if unseen accomplices are necessary.

The discovery of a luminous galaxy 800 million years after the Big Bang supports the scenario where an 'oligarchy' of bright leakers emits most of the ionizing photons.

"It is the first time we can point to an object responsible for creating an ionized bubble, without the need for a contribution from unseen galaxies.

Additional observations with the upcoming James Webb Space Telescope will enable us to study further what is likely one of the best suspects for the unsolved case of cosmic reionization," said Meyer.

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Agencies
January 7,2020

Washington, Jan 7: Facebook will ban deepfake videos ahead of the US elections but the new policy will still allow heavily edited clips so long as they are parody or satire, the social media giant said Tuesday.

Deepfake videos are hyper-realistic doctored clips made using artificial intelligence or programs that have been designed to accurately fake real human movements.

In a blog published following a Washington Post report, Facebook said it would begin removing clips that were edited--beyond for clarity and quality--in ways that "aren't apparent to an average person" and could mislead people.

Clips would be removed if they were "the product of artificial intelligence or machine learning that merges, replaces or superimposes content onto a video, making it appear to be authentic," the statement from Facebook vice-president Monika Bickert said.

However, the statement added: "This policy does not extend to content that is parody or satire, or video that has been edited solely to omit or change the order of words."

US media noted the new guidelines would not cover videos such as the 2019 viral clip -- which was not a deepfake -- of House Speaker Nancy Pelosi that appeared to show her slurring her words.

Facebook also gave no indication on the number of people assigned to identify and take down the offending videos, but said videos failing to meet its usual guidelines would be removed, and those flagged clips would be reviewed by teams of third-party fact-checkers -- among them AFP.

The news agency has been paid by the social media giant to fact-check posts across 30 countries and 10 languages as part of a program starting in December 2016, and including more than 60 organisations.

Content labeled "false" is not always removed from newsfeeds but is downgraded so fewer people see it -- alongside a warning explaining why the post is misleading.

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