Hard As Diamond? 43 New Forms of Superhard C…

Hard As Diamond? 43 New Forms of Superhard Carbon Predicted by Scientists.

A study identifies dozens of new carbon structures that are expected to be superhard, including some that may be about as hard as diamonds.

Superhard materials can slice, drill and polish other objects. They also hold potential for creating scratch-resistant coatings that could help keep expensive equipment safe from damage.

Now, science is opening the door to the development of new materials with these seductive qualities.

Researchers have used computational techniques to identify 43 previously unknown forms of carbon that are thought to be stable and superhard — including several predicted to be slightly harder than or nearly as hard as diamonds. Each new carbon variety consists of carbon atoms arranged in a distinct pattern in a crystal lattice.

The study — published on Sept. 3 in the journal npj Computational Materials — combines computational predictions of crystal structures with machine learning to hunt for novel materials. The work is theoretical research, meaning that scientists have predicted the new carbon structures but have not created them yet.

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High-entropy nanoparticles hold promise for …

High-entropy nanoparticles hold promise for catalytic applications

Alloying is a magic trick used to produce new materials by synergistically mixing at least two metallic elements to form a solid solution. Recent developments in science have found great applications of alloy materials in catalysis, for which nanometer scale bi- or tri-metallic particles are used to accelerate the rate of chemical reactions. But the application of alloys as catalysts is limited by so-called “miscibility,” as not any arbitrary combination of elements can form a homogeneous alloy, neither for robust tuning of the ratio between the two components.

Reported in Nature Communications this week, a research team led by Johns Hopkins University researcher Chao Wang, working with collaborators from the University of Maryland, University of Illinois at Chicago, and University of Pittsburgh, uncovered a new method to break through this limitation. In this work, they mix Co and Mo, two elements that are rarely miscible, but which combination is believed to be important for catalyzing energy-relevant chemical reactions, such as decomposition of ammonia. Instead of directly blending them together, Chao and his team added another three ingredients, Fe, Ni and Cu, all of which are earth-abundant transition metals. When the five elements come together in a particle of nanometer large, a single homogeneous solid solution forms that allows for the incorporation of Co and Mo atoms at various ratios. Scientists call this group of materials “high-entropy alloys.”

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Metal-organic framework nanoribbons

Metal-organic framework nanoribbons

The nanostructure of metal-organic frameworks (MOFs) plays an important role in various applications since different nanostructures usually exhibit different properties and functions. In this work, the authors reported the preparation of ultrathin MOF nanoribbons by using metal hydroxide nanostructures as the precursors. Importantly, this general method can be used to synthesize various kinds of ultrathin MOF nanoribbons. The as-prepared ultrathin nanoribbons have been used for DNA detection, exhibiting excellent sensitivity and selectivity.

Metal-organic frameworks (MOFs) have attracted great attentions in the past decades due to their many noticeable features, such as large surface areas, highly ordered pores, tunable structures and unique functions, making them promising for many applications. The structure engineering of MOFs at the nanometer scale is essential to customize MOFs for specific applications.

Among various nanostructures, ultrathin nanoribbons (NRBs) show great potentials in both fundamental studies and technological applications. Their unique features like high surface-to-volume ratio, highly active surface, and high concentration of selectively exposed crystal facets enable them to exhibit unique electronic structures, mechanical properties, and excellent catalytic efficiency. However, so far, the preparation of ultrathin MOF NRBs still remains a great challenge due to the complicated nucleation and growth processes of MOFs.

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Scientists couple magnetization to supercond…

Scientists couple magnetization to superconductivity for quantum discoveries

Quantum computing promises to revolutionize the ways in which scientists can process and manipulate information. The physical and material underpinnings for quantum technologies are still being explored, and researchers continue to look for new ways in which information can be manipulated and exchanged at the quantum level.

In a recent study, scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory have created a miniaturized chip-based superconducting circuit that couples quantum waves of magnetic spins called magnons to photons of equivalent energy. Through the development of this “on chip” approach that marries magnetism and superconductivity for manipulation of quantum information, this fundamental discovery could help to lay the foundation for future advancements in quantum computing.

Magnons emerge in magnetically ordered systems as excitations within a magnetic material that cause an oscillation of the magnetization directions at each atom in the material—a phenomenon called a spin wave. “You can think of it like having an array of compass needles that are all magnetically linked together,” said Argonne materials scientist Valentine Novosad, an author of the study. “If you kick one in a particular direction, it will cause a wave that propagates through the rest.”

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Diversity Challenge: Celebrating under-represe…

materialsworld:

By Ceri Jones 

Diversity is a hot topic – and rightly so. Science exists to challenge how we work, exploring new ways of thinking and alternative approaches to problem-solving. But the scientific community itself is not immune to scrutiny, and it is important to apply the same keen eye to the socio-political aspects of our working relationships as we do to actual projects.

As an advocate or ally, it is vital that we ask the tough questions around inclusive, intersectional diversity to keep the topic at the front of people’s awareness. To learn more about it, the Materials World team is going to the first ever Diversity Challenge event in London, UK this week.

We spoke to co-founder Luke Davis to find out what to expect on the night.

Luke Davis: 

Science, the incredible body of knowledge that has led to significant medical and technological advances, is presented as something only a privileged group of people can do. In history books, classrooms and in films, we are taught that mainly rich, abled, cis-gendered white men do science. Therefore, those of us who are different find it hard to see ourselves as physicists, engineers, biologists, or programmers. Finding role models who look and talk like us, who have achieved in science, gives us hope that we too can do it.  

Inspired by the popular BBC2 quiz show University Challenge, this newly launched event, Diversity Challenge aims to showcase the incredible stories and achievements of under-represented scientists. It consists of two teams of diverse scientists from around the UK, who battle out their knowledge on under-represented scientists and their work.

Before the mind-boggling quiz there are short talks by early career researchers, highlighting under-represented scientists from the past and the present, while looking to those of the future. The idea is attributed to Luke Davis, a physics PhD student at UCL, who is currently working with co-organiser Dr Faith Uwadiae, an immunologist at the Francis Crick Institute, and Kayisha Payne, a chemical engineer at AstraZeneca and founder of BBSTEM.  

The launch event takes place on ​19 September 2019 at The Royal Institution, London, at 6:00 – 8:00pm​. Assuming the role of Jeremy Paxman as quizmaster, is Dr Suze Kundu, a nanochemist, writer (Forbes Science), presenter, and head of public engagement at Digital Science. Fellow materials scientist, Dr Jessica Boland, a lecturer of functional materials and devices at the University of Manchester, is also taking part.  

Join us at the launch event by getting your tickets here: https://bit.ly/2lSBLsl.

And don’t forget to follow us on Twitter @DiversityChall, where this week we will be tweeting out sample questions to get you ready. 

Think you know your stuff?

Glasses: Smart glass

Glasses: Smart glass

Smart materials are those materials specifically designed to have one or more properties that will change in a desired manner in response to an anticipated external stimuli. Smart glass, then, is any type of glass that fits this category, of which there are many.

Thermochromic glasses are glasses which change color (typically tint) in response to changes in heat. Often these glasses are responsive enough to change in direct response to sunlight, letting in more light (i.e. being more transparent) when the sun is not shining as brightly. This can help control the amount of light needed within a structure, as well as the energy consumption of heating or cooling, depending on the climate. Thermochromic windows are typically produced in layers, as shown in the upper left image above.

Electrochromic glasses, then, are glasses which change color (or tint) in response to the amount of voltage applied to the glass. These types of glasses (often used for windows) allow occupants to tint the glass at will, sometimes for the same reasons as mentioned above, but occasionally simply for comfort or privacy. Electrochromic glasses offer more control than thermochromic glasses, but it requires the ability to control the voltage as well. (The amount of electricity used, however, can be far less than the amount that could potentially be saved by allowing for natural lighting.)

Finally, photochromic glasses also have a similar effect, those these glasses react to the presence of light, not heat as with thermochromic glasses. Photochromic glasses are most popular in lenses.

Other types of smart glass include suspended particle and polymer dispersed liquid crystals. The latter is not actually a form of glass, but rather a layer between the glass. As with electrochromic glass, the application of voltage changes the tint, but PDLCs react much faster than electrochromic materials.

Technically speaking, it is often glazings added to glasses that help produce these effects, which is why windows of these types of glasses are constructed in layers. The movement of ions or electrons through the layers can often be the basis for the change in tint. As such, materials which claim to be ‘smart glass’ are typically combinations of glass and coatings, thin films, or other layers between the glass. There are, however, exceptions.

Sources/Further Reading: ( 1 – image 1 ) ( 2 – image 2 ) ( 3 – image 3 ) ( 4 – image 4 ) ( 5 – image 5 ) ( 6 ) ( 7 ) ( 8 ) ( 9 ) ( 10 )

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