April 08, 2019
Broken phone screens might become a thing of the past! You know how many phones I've gone through? Let's make this happen University of Warwick!
Learn about this and more interesting stories from the scientific community in today's issue.
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*-- No more broken phone screens: New see-through film stronger than aluminum --*
For those in the business of phone repair, researchers in England have some bad news.
Thanks to a new transparent polythene film, shattered phone screens "could be a thing of the past," according to Ton Peijs, professor at the University of Warwick.
Peijs and research partner Cees Bastiaansen, a professor at Queen Mary University of London, developed a new technique for creating the see-through film.
Material engineers have developed impressive high-strength films, including the hot-drawing of high-density polyethylene, HDPE. While these films can compete with the strength of industrial materials, including metals, they're not very transparent, making them poor replacements for glass.
"The microstructure of polymers before drawing very much resembles that of a bowl of cooked spaghetti or noodles, while after stretching or drawing the molecules become aligned in a way similar to that of uncooked spaghetti, meaning that they can carry more load," Yunyin Lin, a PhD student with Peijs and Bastiaansen, said in a news release.
Meanwhile, the most popular transparent plastic replacements for glass, such as polycarbonate, are quite weak.
Peijs and Bastiaansen found they could create polythene films that are see-through and high-strength by fine tuning the drawing temperature.
In the lab, researchers drew out HDPE polythene sheets at a range of temperatures. Scientists found the best balance between strength and transparency was achieved when drawing the sheets between 195 and 230 degrees Fahrenheit.
"We expect greater polymer chain mobility at these high drawing temperatures to be responsible for creating fewer defects in the drawn films, resulting in less light scattering by defects and therefore a higher clarity," Peijs said.
Tests showed the resulting films were 10 times stronger than conventional see-through films. The new transparent polythene film boosted a great maximum tensile strength to that of space grade aluminum. The films are extremely light in weight, making them ideal for uses in small electronics and as an added coating on windshields.
Scientists described their new hot-draw process this week in the journal Polymer.
*-- Scientists trace origins of photons emitted by gamma ray bursts --*
Scientists in Japan have traced the origins of photons emitted by long duration gamma-ray bursts, the brightest electromagnetic events in the universe, to the visible portion of the relativistic jet produced by supernovae.
First discovered in 1967, long duration gamma-ray bursts, or GRBs, are extremely powerful explosions. For decades, scientists struggled to explain the high-energy events. Researchers eventually traced one type of GRB to the relativistic jets produced when massive stars die fiery deaths.
But until now, scientists weren't exactly sure how these jets spark GRBs.
Researchers at the RIKEN Cluster for Pioneering Research in Japan developed models to pinpoint the origins of the high-speed photons produced by GRBs. The team was able to measure the results of their simulations against an important new benchmark called the Yonetoku relation.
The Yonetoku relation describes a tight correlation between spectral peak energy and peak luminosity in GRB emissions.
With the Yonetoku relation as the standard, scientists used their simulations to test what's called the photospheric emission model. The model posits that GRB photons originate in the relativistic jet's photosphere. The quick expansion of the relativistic jet allows photons to escape.
To ensure the precision of their simulations, scientists replicated the complex dynamics of relativistic jets. The results showed the type of long duration gamma-ray bursts that escape the stellar envelope of an exploding massive star yielded the emissions correlation known as the Yonetoku relation.
Interactions between the dying star and relativistic jet naturally produced the Yonetoku relation.
"To us, this strongly suggests that photospheric emission is the emission mechanism of GRBs," Hirotaka Ito, scientist at the Cluster for Pioneering Research, said in a news release.
Ito and his colleagues published their findings Wednesday in the journal Nature Communications.
"While we have elucidated the origin of the photons, there are still mysteries concerning how the relativistic jets themselves are generated by the collapsing stars," Ito said. "Our calculations should provide valuable insights for looking into the fundamental mechanism behind the generation of these tremendously powerful events."