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Category: materials – Page 219

Fastest-ever logic gates could make computers a million times faster

Logic gates are the fundamental building blocks of computers, and researchers at the University of Rochester have now developed the fastest ones ever created. By zapping graphene and gold with laser pulses, the new logic gates are a million times faster than those in existing computers, demonstrating the viability of “lightwave electronics.”

Logic gates take two inputs, compare them, and then output a signal based on the result. They can, for example, output a 1 if both incoming signals are a 1 or a 0, or if either or neither of them is a 1, among other “rules.” Billions of individual logic gates are crammed into chips to create processors, memory and other electronic components.

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Creating a less fragile diamond using fullerenes

A team of researchers from China, Germany and the U.S. has developed a way to create a less fragile diamond. In their paper published in the journal Nature, the group describes their approach to creating a paracrystalline diamond and possible uses for it.

Prior research has shown that diamond is the hardest known material but it is also fragile—despite their hardness, can be easily cut or even smashed. This is because of their ordered atomic structure. Scientists have tried for years to synthesize diamonds that retain their hardness but are less fragile. The team has now come close to achieving that goal.

Currently, the way to create diamonds is to place a carbon-based material in a vice-like device where it is heated to very high temperatures while it is squeezed very hard. In this new effort, the researchers have used the same approach to create a less ordered type of diamond but have added a new twist—the carbon-based material was a batch of fullerenes, also known as buckyballs ( arranged in a hollow spherical shape). They heated the material to between 900 and 1,300 °C at pressures of 27 to 30 gigapascals. Notably, the pressure exerted was much lower than is used to make commercial diamonds. During processing, the spheres were forced to collapse, and they formed into transparent paracrystalline diamonds which could be extracted at room temperature.

Scientists develop powerful family of 2D materials

A team from the Tulane University School of Science and Engineering has developed a new family of two-dimensional materials that researchers say has promising applications, including in advanced electronics and high-capacity batteries.

Led by Michael Naguib, an assistant professor in the Department of Physics and Engineering Physics, the study has been published in the journal Advanced Materials.

“Two-dimensional are nanomaterials with thickness in the nanometer size (nanometer is one millionth of a millimeter) and lateral dimensions thousands of times the thickness,” Naguib said. “Their flatness offers unique set of properties compared to bulk materials.”

Rechargeable Molten Salt Battery Freezes Energy in Place for Long-Term Storage

Creating a battery that can withstand repeated cycles of heating and cooling is no small feat. Temperature fluctuations cause the battery to expand and contract, and the researchers had to identify resilient materials that could tolerate these changes. “What we’ve seen before is a lot of active research to make sure you do not have to go through that thermal cycle,” says Vince Sprenkle, a strategic advisor in energy storage at PNNL and a co-author of the new paper. “We’re saying, ‘We want to go through it, and we want to be able to survive and use that as a key feature.’”

The result is a rechargeable battery made from relatively inexpensive materials that can store energy for extended periods. “It’s a great example of a promising long-duration energy-storage technology,” says Aurora Edington, policy director of the electricity industry association GridWise Alliance, who was not involved with this research. “I think we need to support those efforts and see how far we can take them to commercialization.”

The technology could be particularly useful in a place such as Alaska, where near-constant summer sunlight coincides with relatively low rates of energy use. A battery that can store energy for months could allow abundant summer solar power to fulfill winter electricity needs. “What is so attractive about the freeze-thaw battery is that seasonal shifting capability,” says Rob Roys, chief innovation officer at Launch Alaska, a nonprofit organization that works to accelerate the deployment of climate technologies in the state. Roys hopes to pilot the PNNL battery in a remote part of his state.

Ceramic 3D Printing Capabilities Expand with New Admatec Debinding and Sintering Equipment

Admatec has steadily been increasing its 3D printing capabilities, taking its slurry-based digital light processing (DLP) process further. First it expanded from resins loaded with ceramic particles to those loaded with metal particles. It then increased the build volume of its Admaflex300 3D printer. Now, the company has introduced a new integrated debinding and sintering furnace with a larger work volume.

The majority of ceramic 3D printing processes rely on the use of a photopolymer slurry loaded with ceramic particles. Once printed, these green parts first go through a debinding process, in which the photopolymer material is removed, followed by sintering, causing the part to become fully dense.

Mars scientists discover a puzzling impact crater on the Red Planet

Most craters are circular in shape due to material ejecting out in all directions as a result of an impact. Below is a group of impact craters in Noachis Terra, a large region in Mars’ southern hemisphere. These are all classified as simple craters, which are small bowl-shaped, smooth-walled craters.

Complex craters, on the other hand, are large craters with complicated features, such as terraces, central peaks, and rims and walls their own features. Oblong craters, like the one in the lead image — which is also located in Noachis Terra — can sometimes be created by impacts striking the surface at a very low grazing angle.

Ultra-thin speakers roll out like wallpaper for sound-blasting surfaces

Engineers at MIT have developed an ultra-thin speaker that could be used to make entire surfaces produce sound. The unique design should be energy efficient and easy to produce at scale, the team says.

In a basic sense, speakers work by vibrating a membrane, which manipulates the air above it to produce sound waves. In speakers commonly found in audio systems or headphones, that’s done using electrical currents and magnetic fields.

But in recent years scientists have developed ways to achieve similar results in much slimmer devices. Thin film speakers work using piezoelectric materials, which vibrate in response to the application of a voltage. These have been used in phones and TVs, and even experimentally to create speakers out of things as unusual as flags.

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