NASA’s Marshall Spaceflight Center recently tested a novel aluminum alloy 6061-RAM2 3D printed rocket nozzle. They ran it with both LH2/LOX and CH4/LOX to test its performance in high heat environments. Usually aluminum cracks under these conditions but this new alloy is promising for weight savings and ease of manufacturing.
Researchers at the University of Tokyo have developed an innovative plastic that is stronger and stretchier than the current standard type. The plastic is also partially biodegradable, remembers its shape, and can be healed with heat. The researchers created it by adding the molecule polyrotaxane to an epoxy resin vitrimer, a type of plastic.
Named VPR, the material can hold its form and has strong internal chemical bonds at low temperatures. However, at temperatures above 150° Celsius, those bonds recombine and the material can be reformed into different shapes.
Applying heat and a solvent breaks VPR down into its raw components. Submerging it in seawater for 30 days also resulted in 25% biodegradation, with the polyrotaxane breaking down into a food source for marine life. This new material could have wide-reaching applications for a more circular economy to recirculate resources and reduce waste, from engineering and manufacturing, to medicine and sustainable fashion.
The way light interacts with naturally occurring materials is well-understood in physics and materials science. But in recent decades, researchers have fabricated metamaterials that interact with light in new ways that go beyond the physical limits imposed on naturally occurring materials.
A metamaterial is composed of arrays of "meta-atoms," which have been fabricated into desirable structures on the scale of about a hundred nanometers. The structure of arrays of meta-atoms facilitate precise light-matter interactions. However, the large size of meta-atoms relative to regular atoms, which are smaller than a nanometer, has limited the performance of metamaterials for practical applications.
Now, a collaborative research team led by Bo Zhen of the University of Pennsylvania has unveiled a new approach that directly engineers atomic structures of material by stacking the two-dimensional arrays in spiral formations to tap into novel light-matter interaction. This approach enables metamaterials to overcome the current technical limitations and paves the way for next-generation lasers, imaging, and quantum technologies. Their findings were published in the journal Nature Photonics.
Read more here: https://www.futurity.org/quasicrystal- ... 97912-2/(Futurity) Nanoengineers have created a quasicrystal—a scientifically intriguing and technologically promising material structure—from nanoparticles using DNA, the molecule that encodes life.
The team reports the results in the journal Nature Materials.
Unlike ordinary crystals, which are defined by a repeating structure, the patterns in quasicrystals don’t repeat. Quasicrystals built from atoms can have exceptional properties—for example, absorbing heat and light differently, exhibiting unusual electronic properties such as conducting electricity without resistance, or their surfaces are very hard or very slippery.
Engineers studying nanoscale assembly often view nanoparticles as a kind of “designer atom,” which provides a new level of control over synthetic materials. One of the challenges is directing particles to assemble into desired structures with useful qualities, and in building this first DNA-assembled quasicrystal, the team entered a new frontier in nanomaterial design.
Somewhat squashed pentagonal bipyramids pack together on the left side of the image (see link below to view image), fading into a ball-and-stick model of the connections between neighboring particles. The model sketches out triangles and rhombuses without a consistent pattern, as each ball has five or six connections.
A team led by chemists at the University of Liège has developed a new polyurethane production technique using CO2 to create new types of easily recyclable plastics. The study, published in the Journal of the American Chemistry Society, could provide a solution for the development of truly sustainable plastics.
Commodity plastics have transformed global industry. Whether in construction, clothing, vehicles or food packaging, these plastics are everywhere in our daily lives, so much so that their global use has been estimated at around 460 million tons in 2019.
"This number is staggering, but not surprising, because plastics, also known as synthetic polymers, have met a large success thanks to their irreplaceable characteristics: they are light, cheap and incredibly versatile," explains Christophe Detrembleur, chemist at the Center for Education and Research on Macromolecules (CERM) of the University of Liège. "However, the fact that they are difficult to recycle, or even impossible to recycle in the case of thermosets, has serious consequences."
https://www.extremetech.com/science/goo ... structuresSome 380,000 of them are believed to be stable enough to aid in developing new technology.
Using artificial intelligence to create new things is all the rage right now. Whether you want text, computer code, or images, there are uncountable generative AI models that can oblige. Google DeepMind announces that it has developed an AI model to generate something else: crystal structures. Its new Graph Networks for Materials Exploration (GNoME) system has successfully generated 2.2 million new crystalline materials, and the team thinks 380,000 of them are stable enough to be helpful in advanced technology.
Here is an article that has a little bit more background on this: https://www.axios.com/2023/12/02/ai-rob ... -materialsweatheriscool wrote: ↑Fri Dec 01, 2023 5:14 pm Google DeepMind AI Predicts Millions of New Crystal Structureshttps://www.extremetech.com/science/goo ... structuresSome 380,000 of them are believed to be stable enough to aid in developing new technology.
Using artificial intelligence to create new things is all the rage right now. Whether you want text, computer code, or images, there are uncountable generative AI models that can oblige. Google DeepMind announces that it has developed an AI model to generate something else: crystal structures. Its new Graph Networks for Materials Exploration (GNoME) system has successfully generated 2.2 million new crystalline materials, and the team thinks 380,000 of them are stable enough to be helpful in advanced technology.
December 4, 2023 by Brian WangLow Temperature Liquid Metal Could Save 90% of Chemical Industry Energy
Chemical production using solid processes is energy intensive and causes over 10% of greenhouse emissions by requiring temperatures of up to a thousand degrees centigrade.
A new process instead uses liquid metals, in this case dissolving tin and nickel which gives them unique mobility, enabling them to migrate to the surface of liquid metals and react with input molecules such as canola oil. This results in the rotation, fragmentation, and reassembly of canola oil molecules into smaller organic chains, including propylene, a high-energy fuel crucial for many industries.
Reserarchers dissolved high melting point nickel and tin in a gallium based liquid metal with a melting point of only 30 degrees centigrade. Dissolving nickel in liquid gallium let them get access to liquid nickel at very low temperatures. This acts as a ‘super’ catalyst. In comparison solid nickel’s melting point is 1455 degrees centigrade. The same effect, to a lesser degree, is also experienced for tin metal in liquid gallium,” Dr Tang said.
Read more here: https://www.sciencealert.com/cracked-p ... ientists(Science Alert) File this under 'That's not supposed to happen!': Scientists observed a metal healing itself, something never seen before. If this process can be fully understood and controlled, we could be at the start of a whole new era of engineering.
In a study published in July, a team from Sandia National Laboratories and Texas A&M University was testing the resilience of the metal, using a specialized transmission electron microscope technique to pull the ends of the metal 200 times every second.
They then observed the self-healing at ultra-small scales in a 40-nanometer-thick piece of platinum suspended in a vacuum.
Cracks caused by the kind of strain described above are known as fatigue damage: repeated stress and motion that causes microscopic breaks, eventually causing machines or structures to break.
Amazingly, after about 40 minutes of observation, the crack in the platinum started to fuse back together and mend itself before starting again in a different direction.
An international team of experts undertaking fundamental research has developed a way of using polyethylene waste (PE) as a feedstock and converted it into valuable chemicals, via light-driven photocatalysis.
The University of Adelaide's Professor Shizhang Qiao, Chair of Nanotechnology, and Director, Center for Materials in Energy and Catalysis, at the School of Chemical Engineering, led the team that published their findings in the journal Science Advances.
"We have upcycled polyethylene plastic waste into ethylene and propionic acid with high selectivity using atomically dispersed metal catalysts," said Professor Qiao.
"An oxidation-coupled room-temperature photocatalysis method was used to convert the waste into valuable products with high selectivity. Nearly 99% of the liquid product is propionic acid, alleviating the problems associated with complex products that then require separation. Renewable solar energy was used rather than industrial processes that consume fossil fuel and emit greenhouse gases."
