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A liquid crystal elastomer fiber can produce morphing fabrics

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An interdisciplinary MIT team has developed FibeRobo- a programmable, actuating fiber that could someday be used in textiles. This thermally-actuated liquid crystal elastomer (LCE) fiber could enable silent and responsive interactions with shape-changing, fiber-based interfaces.

Fiberobo contracts in response to an increase in temperature, then self-reverses when the temperature decreases, without any embedded sensors or other complex components. It can be coupled with a conductive thread, an element when an electric current is heated. In this sense, the fibers are electrically actuated, giving the user digital control over the shape of a textile. A fabric might, for example, alter its structure in response to any digital data, including heart rate sensor measurements.

The drawbacks of the current shape-changing fibers have mainly prohibited their use in textiles outside of experimental settings.

A single fiber, a shape-changing alloy, seldom ceases functioning after a few actions, only contracts by roughly 5%, and cannot self-reverse. Another is a pneumatically powered device, a McKibben actuator, which needs an air compressor to operate.

The MIT researchers’ project aimed to create a fiber that could function silently, undergo significant morphological changes and work with standard textile production processes. They employed a liquid crystal elastomer (LCE) to do this.

Caption:The fiber contracts in response to an increase in temperature, then self-reverses when the temperature decreases, without any embedded sensors or other hard components. Credit: MIT

A liquid crystal comprises a group of molecules that flow like liquids yet stack into periodic crystal arrangements when given time to settle. The scientists integrate these crystal structures into an elastic network called an elastomer, which resembles a rubber band.

The fiber contracts as the LCE material heats up because the crystal molecules misalign and pull the elastomer network together. According to Forman, when the heat is removed, the molecules realign, and the material stretches to its initial length.

The ultimate characteristics of the fiber, such as its thickness and the temperature at which it actuates, may be precisely controlled by the researchers by carefully combining chemicals to create the LCE. They developed a method of preparation that yields LCE fiber that is acceptable for wearable fabrics and can actuate at temperatures that are safe for human skin. This was not possible for scientists to achieve with other LCE fibers.

In their study, scientists built a machine using 3D-printed and laser-cut parts and basic electronics to overcome the fabrication challenges. They begin by heating the thick and dense LCE resin and then slowly squeezing through a nozzle like a glue gun.

After extracting the resin, it is carefully cured with UV rays on both sides of the fiber as it progressively extrudes.

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The material will separate and flow out of the machine if the light is too faint, but clumps may form if the light is too bright, resulting in rough strands.

After that, the fiber is coated with oil to make it slippery and is once more cured under intense UV radiation to produce a robust and smooth yarn. The material is gathered onto a top spool and coated with powder to facilitate its easy insertion into textile manufacturing machinery.

The entire process, from chemical synthesis to completed spool, takes about one day and yields roughly one kilometer of usable fiber.

As scientists reported, FibeRobo can contract up to 40 percent without bending actuate at skin-safe temperatures. It can be produced with a low-cost setup for 20 cents per meter, which is about 60 times cheaper than commercially available shape-changing fibers.

industrial knitting machine
Caption: They also used an industrial knitting machine to create a compression jacket for lead author Jack Forman’s dog, whose name is Professor. The jacket would actuate and “hug” the dog based on a Bluetooth signal from Forman’s smartphone. Credits: MIT

Using the Fiberobo, scientists created a jacket for a dog named Professor. The jacket would ” hug ” the dog when it received a Bluetooth signal from Forman’s smartphone. When a dog’s owner is away, compression jackets are frequently used to help ease their separation anxiety.

Lining Yao, the Cooper-Siegel Associate Professor of Human-Computer Interaction at Carnegie Mellon University, who was not involved with this work, said“LCE fibers come to life when integrated into functional textiles. It is particularly fascinating to observe how the authors have explored creative textile designs using a variety of weaving and knitting patterns.”

Journal Reference:

  1. Jack Forman, Ozgun Kilic Afsar, Sarah Nicita et al. FibeRobo: Fabricating 4D Fiber Interfaces by Continuous Drawing of Temperature Tunable Liquid Crystal Elastomers. ACM Symposium on User Interface Software and Technology. DOI: 10.1145/3586183.3606732

 

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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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