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Category: materials – Page 340

A new test could tell us whether an AI has common sense

Virtual assistants and chatbots don’t have a lot of common sense. It’s because these types of machine learning rely on specific situations they have encountered before, rather than using broader knowledge to answer a question. However, researchers at the Allen Institute for AI (Ai2) have devised a new test, the Arc Reasoning Challenge (ARC) that can test an artificial intelligence on its understanding of the way our world operates.

Humans use common sense to fill in the gaps of any question they are posed, delivering answers within an understood but non-explicit context. Peter Clark, the lead researcher on ARC, explained in a statement, “Machines do not have this common sense, and thus only see what is explicitly written, and miss the many implications and assumptions that underlie a piece of text.”

The test asks basic multiple-choice questions that draw from general knowledge. For example, one ARC question is: “Which item below is not made from a material grown in nature?” The possible answers are a cotton shirt, a wooden chair, a plastic spoon and a grass basket.

Could hemp nanosheets topple graphene for making the ideal supercapacitor?

As hemp makes a comeback in the U.S. after a decades-long ban on its cultivation, scientists are reporting that fibers from the plant can pack as much energy and power as graphene, long-touted as the model material for supercapacitors. They’re presenting their research, which a Canadian start-up company is working on scaling up, at the 248th National Meeting & Exposition of the American Chemical Society (ACS).

David Mitlin, Ph.D., explains that are energy storage devices that have huge potential to transform the way future electronics are powered. Unlike today’s rechargeable batteries, which sip up energy over several hours, supercapacitors can charge and discharge within seconds. But they normally can’t store nearly as much energy as batteries, an important property known as energy density. One approach researchers are taking to boost supercapacitors’ energy density is to design better electrodes. Mitlin’s team has figured out how to make them from certain fibers—and they can hold as much energy as the current top contender: graphene.

“Our device’s electrochemical performance is on par with or better than graphene-based devices,” Mitlin says. “The key advantage is that our electrodes are made from biowaste using a simple process, and therefore, are much cheaper than graphene.”

Scientists successfully inverted the circularly propagating optical waves

A new study has revealed that the optical waves or light waves can be turned upside down when they are allowed to propagate through specifically structured surfaces. Normally what happens is that the optical waves emerging out from a point source propagate circularly. That means the optical waves traveling away from a point source characteristically display circular, or convex, wavefronts.

The scientists compared these circular wavefronts to the waves seen on the water surface when a stone is dropped into the water. But the latest study revealed that these circularly propagating light waves’ wavefronts can be turned upside down with the help of a special surface. They developed a new material having a hyperbolic metasurface and successfully inverted the optical waves.

The study was led by Peining Li, an EU Marie Sklodowska-Curie fellow at nanoGUNE. According to him, the reason behind this circular propagation of optical waves is because of the fact that the medium through which light waves propagate is isotropic and homogenous. If the waves are isotropic in nature then their propagation is uniform in all direction and being homogenous means they carry the same characteristics throughout the propagation. But these optical waves can be inverted using specifically structured surfaces like the hyperbolic metasurfaces.

This New Graphene Invention Makes Filthy Seawater Drinkable in One Simple Step

Using a type of graphene called Graphair, scientists from Australia have created a water filter that can make highly polluted seawater drinkable after just one pass.

The technology could be used to cheaply provide safe drinking water to regions of the world without access to it.

“Almost a third of the world’s population, some 2.1 billion people, don’t have clean and safe drinking water,” said lead author Dong Han Seo.

Researchers create first superatomic 2-D semiconductor

(Left) Superatomic structure and (right) exfoliated 15-nm-thick flakes of the material Re6Se8Cl2. Credit: Zhong et al. ©2018 American Chemical Society Atoms are the basic building blocks of all matter—at least, that is the conventional picture. In a new study, researchers have fabricated the first superatomic 2-D semiconductor, a material whose basic units aren’t atoms but superatoms—atomic clusters that exhibit some of the properties of one or more individual atoms. The researchers expect that the new material is just the first member of what will become a new family of 2-D semiconductors…

Graphene film makes dirty water drinkable in a single step

Every year, millions of people around the world die from drinking unclean water. Now, researchers have developed a process that can purify water, no matter how dirty it is, in a single step. Scientists from Australian research organization CSIRO have created a filtration technique using a graphene film with microscopic nano-channels that lets water pass through, but stops pollutants. The process, called “Graphair”, is so effective that water samples from Sydney Harbor were safe to drink after being treated.

And while the film hails from graphene, Graphair is comparatively cheaper, faster and more environmentally-friendly to make, as its primary component is renewable soybean oil, which also helps maximise the efficiency of the purifying technique’s filter counterpart. Over time, oil-based pollutants can impede water filters, so contaminants have to be removed before filtering can even begin, but using Graphair removes these pollutants faster than any other method.

Water purification usually involves a complex process of several steps, so this breakthrough could have a significant impact on the some 2.1 billion people who don’t have clean, safe drinking water. “All that’s needed is heat, our graphene, a membrane filter and a small water pump. We’re hoping to commence field trials in a developing world community next year,” said lead author Dr Dong Han Seo, who added that the team is looking for industry partners to help scale up the technology, and is also working on other applications for Graphair, such as seawater and industrial effluents.

Microscopy breakthrough paves the way for atomically precise manufacturing

A University of Texas at Dallas graduate student, his advisor and industry collaborators believe they have addressed a long-standing problem troubling scientists and engineers for more than 35 years: How to prevent the tip of a scanning tunneling microscope from crashing into the surface of a material during imaging or lithography. Details of the group’s solution appeared in the January issue of the journal Review of Scientific Instruments, which is published by the American Institute of Physics. Scanning tunneling microscopes (STMs) operate in an ultra-high vacuum, bringing a fine-tipped p…

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