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Category: materials – Page 180

Shock-formed carbon materials with intergrown sp3- and sp2-bonded nanostructured units

Studies of dense carbon materials formed by bolide impacts or produced by laboratory compression provide key information on the high-pressure behavior of carbon and for identifying and designing unique structures for technological applications. However, a major obstacle to studying and designing these materials is an incomplete understanding of their fundamental structures. Here, we report the remarkable structural diversity of cubic/hexagonally (c/h) stacked diamond and their association with diamond-graphite nanocomposites containing sp3-/sp2-bonding patterns, i.e., diaphites, from hard carbon materials formed by shock impact of graphite in the Canyon Diablo iron meteorite. We show evidence for a range of intergrowth types and nanostructures containing unusually short (0.31 nm) graphene spacings and demonstrate that previously neglected or misinterpreted Raman bands can be associated with diaphite structures. Our study provides a structural understanding of the material known as lonsdaleite, previously described as hexagonal diamond, and extends this understanding to other natural and synthetic ultrahard carbon phases. The unique three-dimensional carbon architectures encountered in shock-formed samples can place constraints on the pressure–temperature conditions experienced during an impact and provide exceptional opportunities to engineer the properties of carbon nanocomposite materials and phase assemblages.

New Graphene Electronic Tattoos Kickstart Healthcare Electronics 2.0

Graphene electronic tattoos are unique devices used in healthcare systems for personalized applications. Monolayered graphene electronic tattoos are used to monitor different electrophysiological signals in humans. Despite their innovative functionality, these devices suffer from an impermeability to sweat and difficulties in reproducibility.

Study: Graphene electronic tattoos 2.0 with enhanced performance, breathability and robustness. Image Credit: Tex vector/Shutterstock.com.

In an article recently published in the journal npj 2D Materials and Applications, an enhanced version of graphene electronic tattoos was introduced. This update is wearable on the skin with sweat permeability, superior electrical properties, and robustness. While the older systems suffered scattered electrical properties due to growth or transfer-related discrepancies, the reported graphene electronic tattoos with graphene nanoscrolls (GNS) or multilayered graphene structures showed enhanced properties.

Team tests the effects of oxygen on uranium

A team of researchers from Lawrence Livermore National Laboratory (LLNL) and the University of Michigan has found that the rate of cooling in reactions dramatically affects the type of uranium molecules that form.

The team’s experimental work, conducted over about a year and a half starting in October 2020, attempts to help understand what uranium compounds might form in the environment after a nuclear event. It has recently been detailed in Scientific Reports.

“One of our most important findings was learning that the rate of cooling affects the behavior of uranium,” said Mark Burton, the paper’s lead author and a chemist in the Lab’s Materials Science Division. “The big picture here is that we want to understand uranium chemistry in energetic environments.”

Vibrational Energy Harvester Taps Graphene for a Potential Unlimited Energy Source

Circa 2018 unlimited energy using graphene.

University of Arkansas researchers have shown that the motion of graphene could supply an unlimited amount of clean energy. (Image credit: Pixabay)Graphene advancements are rolling out on a regular basis, with new developments in production 0, strength 0, and have even used it to create 3D printed objects. Researchers from the University of Arkansas have also utilized the material to create a source of potential unlimited clean energy, thanks to its flexibility.

The observation of Chern mosaic and Berry-curvature magnetism in magic angle graphene

Researchers at the Weizmann Institute of Science, the Barcelona Institute of Science and Technology and the National Institute for Material Science in Tsukuba (Japan) have recently probed a Chern mosaic topology and Berry-curvature magnetism in magic-angle graphene. Their paper, published in Nature Physics, offers new insight about topological disorder that can occur in condensed matter physical systems.

“Magic angle twisted (MATBG) has drawn a huge amount of interest over the past few years due to its experimentally accessible flat bands, creating a playground of highly correlated physics,” Matan Bocarsly, one of the researchers who carried out the study, told Phys.org, “One such correlated phase observed in transport measurements is the quantum anomalous Hall effect, where topological edge currents are present even in the absence of an applied .”

The quantum anomalous Hall effect is a charge transport-related phenomenon, in which a material’s Hall resistance is quantized to the so-called von Klitzing constant. It resembles the so-called integer quantum Hall effect, which Bocarsly and his colleagued had studied extensively in their previous works, particularly in graphene and MATBG.

July 1957: Bardeen, Cooper, and Schrieffer submit their paper, “Theory of Superconductivity”

Bardeen, Cooper and Schrieffer (left to right)

In 1911, Heike Kamerlingh Onnes, in his quest to study materials at ever lower temperatures, happened to find that the electrical resistance of some metallic materials suddenly vanished at temperatures near absolute zero. He called the phenomenon superconductivity, and scientists soon found additional materials that exhibited this property.

But no one could completely explain how it worked. For the next few decades, many prominent physicists worked to develop a theory of the mechanism underlying superconductivity, but no one had much success, and some despaired of figuring it out. One such physicist, Felix Bloch, was quoted as proposing “Bloch’s theorem: Superconductivity is impossible.”

The Advanced Materials That Can Help Take Us to Mars

Scientists, designers and engineers across the space industry are working tirelessly to form innovative solutions for traveling to, living on and further understanding Mars.

Mars has long occupied our imagination as a site of wonder and possibility in film — from the high-tech invasion portrayed in The War of the Worlds to Andy Weir’s perhaps more accurate depiction The Martian.

Today, reality is closer than ever to the dreams of science fiction. As early as the 2030s, humans will be able to visit Earth’s planetary neighbor in the most ambitious aerospace mission yet.

The key to becoming an interplanetary species? Cutting-edge materials. Thankfully, scientists, designers, and engineers across the space industry are working tirelessly to form innovative solutions for traveling to, living on, and further understanding Mars.

Researchers develop antiviral face mask that can capture, deactivate SARS-CoV-2 spike protein on contact

A team of University of Kentucky researchers led by College of Engineering Professor Dibakar Bhattacharyya, Ph.D., and his Ph.D. student, Rollie Mills, have developed a medical face mask membrane that can capture and deactivate the SARS-CoV-2 spike protein on contact.

At the beginning of the COVID-19 pandemic in 2020, Bhattacharyya, known to friends and colleagues as “DB,” along with collaborators across disciplines at UK set out to create the material. Their work was published in Communications Materials on May 24.

SARS-CoV-2 is covered in spike proteins, which allow the virus to enter host cells once in the body. The team developed a membrane that includes that attach to the protein spikes and deactivates them.

Mushrooms could solve a huge problem in outer space

Circa 2021

Mycelium is very light in weight, it naturally floats on water, it can withstand the cold of space where we don’t have to worry about cold welding, and we can add in fine strains of metal material which is used to transmit almost any type of signal. As you can see, there are numerous reasons why mycelium is quite suitable for our satellites in space, on land, and in the air on its way to space.

Of course, there’s also the all-important issue of space debris, which is projected to become a severe hazard to satellites and spacecraft in Low Earth Orbit (LEO) in the coming years.

According to the SDO, more than 560 break-ups, explosions, collisions, or anomalous events that resulted in fragmentation have taken place since the launch of the first artificial satellite in 1957 (Sputnik 1). With the proliferation of small satellites and the mega-constellations that are (or soon will be) deployed, the risk of collision rises considerably.