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HPC helps identify new, cleaner source for white light – EurekAlert

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image: Upon irradiation by infrared light, adamantane-based molecular clusters with the general composition [(RT)4E5] (with R = organic group; T = C, Si, Ge, Sn; E = O, S, Se, Te, NH, CH2, ON•) emit highly directional white light.
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Credit: Elisa Monte, Justus-Liebig-Universität Gießen

When early humans discovered how to harness fire, they were able to push back against the nightly darkness that enveloped them. With the invention and widespread adoption of electricity, it became easier to separate heat from light, work through the night, and illuminate train cars to highways. In recent years, old forms of electric light generation such as halogen lightbulbs have given way to more energy efficient alternatives, further cheapening the costs to brighten our homes, workplaces, and lives generally.

Unfortunately, however, white light generation by newer technologies such as light-emitting diodes (LEDs) is not straightforward and often relies on a category of materials called “rare-earth metals,” which are increasingly scarce. This has recently led scientists to look for ways to produce white light more sustainably. Researchers at Giessen University, the University of Marburg, and Karlsruhe Institute of Technology have recently uncovered a new class of material called a “cluster glass” that shows great potential for replacing LEDs in many applications.

“We are witnessing the birth of white-light generation technology that can replace current light sources. It brings all the requirements that our society asks for: availability of resources, sustainability, biocompatibility,” said Prof. Dr. Simone Sanna, Giessen University Professor and lead computational researcher on the project.  “My colleagues from the experimental sciences, who observed this unexpected white light generation, asked for theoretical support. Cluster glass has an incredible optical response, but we don’t understand why. Computational methods can help to understand those mechanisms. This is exactly the challenge that theoreticians want to face.”

Sanna and his collaborators have turned to the power of high-performance computing (HPC), using the Hawk supercomputer at the High-Performance Computing Center Stuttgart (HLRS) to better understand cluster glass and how it might serve as a next-generation light source. They published their findings in Advanced Materials.

Clear-eyed view on cluster glass formation

If you are not a materials scientist or chemist, the word glass might just mean the clear, solid material in your windows or on your dinner table. Glass is actually a class of materials that are considered “amorphous solids;” that is, they lack an ordered crystalline lattice, often due to a rapid cooling process. At the atomic level, their constituent particles are in a suspended, disordered state. Unlike crystal materials, where particles are orderly and symmetrical across a long molecular distance, glasses’ disorder at the molecular level make them great for bending, fragmenting, or reflecting light.

Experimentalists from the University of Marburg recently synthesized a particular of glass called a “cluster glass.” Unlike a traditional glass that almost behaves as a liquid frozen in place, cluster glass, as the name implies, is a collection of separate clusters of molecules that behave as a powder at room temperature. They generate bright, clear, white light upon irradiation by infrared radiation.  While powders cannot easily be used to manufacture small, sensitive electronic components, the researchers found a way to re-cast them in glass form: “When we melt the powder, we obtain a material that has all the characteristics of a glass and can be put in any form needed for a specific application,” Sanna said.

While experimentalists were able to synthesize the material and observe its luminous properties, the group turned to Sanna and HPC to better understand how cluster glass behaves the way it does. Sanna pointed out that white light generation isn’t a property of a single molecule in a system, but the collective behaviors of a group of molecules. Charting these molecules’ interactions with one another and with their environment in a simulation therefore means that researchers must both capture the large-scale behaviors of light generation and also observe how small-scale atomic interactions influence the system. Any of these factors would be computationally challenging. Modeling these processes at multiple scales, however, is only possible using leading HPC resources like Hawk.

Collaboration between experimentalists and theoreticians has become increasingly important in materials science, as synthesizing many iterations of a similar material can be slow and expensive. High-performance computing, Sanna indicated, makes it much faster to identify and test materials with novel optical properties. “The relationship between theory and experiment is a continuous loop. We can predict the optical properties of a material that was synthesized by our chemist colleagues, and use these calculations to verify and better understand the material’s properties,” Sanna said. “We can also design new materials on a computer, providing information that chemists can use to focus on synthesizing compounds that have the highest likelihood of being useful. In this way, our models inspire the synthetization of new compounds with tailored optical properties”

In the case of cluster glass, this approach resulted in an experiment that was verified by simulation, with modelling helping to show the researchers the link between the observed optical properties and the molecular structure of their cluster glass material and can now move forward as a candidate to replace light sources heavily reliant on rare-earth metals.

HPC expedites R&D timelines

HPC plays a major role in helping researchers accelerate the timeline between new discovery and new product or technology. Sanna explained that HPC drastically cut down on the time to get a better understanding of cluster glass. “We spend a lot of time doing simulation, but it is much less than characterizing these materials in reality,” he said. “The clusters we model have a diamond-shaped core with 4 ligands (molecular chains) attached to it. Those ligands can be made of any number of things, so doing this in an experiment is time consuming.”

Sanna pointed out that the team is still limited by how long they can perform individual runs for their simulations. Many research projects on supercomputers can divide a complex system into many small parts and run calculations for each part in parallel. Sanna’s team needs to pay special attention to long-distance particle interactions across large systems, so they are limited by how much they can divide their simulation across computer nodes. He indicated that having regular access to longer run times—more than a day straight on a supercomputer—would allow the team to work more quickly.  

In ongoing studies of cluster glass Sanna’s team hopes to thoroughly understand the origin of its light generating properties. This could help to identify additional new materials and to determine how best to apply cluster glass in light generation.

Sanna explained that HPC resources at HLRS were essential for his team’s basic science research, which he hopes will lead to new products that can benefit society. “The main computational achievement in this journal article was only possible through our access to the machine in Stuttgart,” he said.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

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More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

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Follow AP’s climate coverage at https://apnews.com/hub/climate

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Follow Seth Borenstein on Twitter at @borenbears

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Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

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‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

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It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

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The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

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TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

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