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Category: materials – Page 111

In the three-dimensional printing process of ceramic with low-angle structures, additional supporting structures are usually employed to avoid collapse of overhanging parts. However, the extra supporting structures not only affect printing efficiency, but the problems caused by their removal are also a matter of concern. Herein, we present a ceramic printing method, which can realize printing of unsupported multi-scale and large-span ceramics through the combination of direct ink writing and near-infrared induced up-conversion particles-assisted photopolymerization. This printing technology enables in-situ curing of multi-scale filaments with diameters ranging from 410 µm to 3.50 mm, and ceramic structures of torsion spring, three-dimensional bending and cantilever beam were successfully constructed through unsupported printing. This method will bring more innovation to the unsupported 3D manufacturing of complex shape ceramics.

In 3D ceramic printing, the need for additional supports can increase processing time and introduce defects during post-processing removal. Here, authors merge direct ink writing and up-conversion particles-assisted photopolymerization under near-infrared irradiation for support-free printing with controlled curing rates reducing material waste, printing time, and post-processing steps.

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Meeting the world’s energy demands is reaching a critical point. Powering the technological age has caused issues globally. It is increasingly important to create superconductors that can operate at ambient pressure and temperature. This would go a long way toward solving the energy crisis.

Advancements with superconductivity hinge on advances in . When electrons inside of quantum materials undergo a phase transition, the electrons can form intricate patterns, such as fractals. A fractal is a never-ending pattern. When zooming in on a fractal, the image looks the same. Commonly seen fractals can be a tree or frost on a windowpane in winter. Fractals can form in two dimensions, like the frost on a window, or in three-dimensional space like the limbs of a tree.

Dr. Erica Carlson, a 150th Anniversary Professor of Physics and Astronomy at Purdue University, led a team that developed theoretical techniques for characterizing the fractal shapes that these electrons make, in order to uncover the underlying physics driving the patterns.

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An unusual quasicrystal has been discovered by a team from the Martin Luther University Halle-Wittenberg (MLU), the University of Sheffield and Xi’an Jiaotong University. It has a dodecagonal honeycomb structure that has never been seen before. Until now, similar quasicrystals were only known to come in a solid—not liquid—form. The team presents its results in the journal Nature Chemistry.

Quasicrystals have a special structure. They have a regular pattern similar to normal crystals, however, in normal crystals, the arrangement of the individual components is repeated over and over at . In the case of quasicrystals, the components do not fit together in such a periodic pattern. This special structure gives them special properties that normal crystals do not have.

The newly discovered consists of dodecagons, which in turn are made up of a mixture of triangular, square and, for the first time, trapezoidal shaped cells. These are generated from the self-assembly of “T-shaped” molecules. “We have discovered a perfectly ordered liquid quasicrystal. Such a material has never been seen before,” says chemist Professor Carsten Tschierske at MLU.

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In a study published in Nature Communications, Prof. Xiang Bin’s group from University of Science and Technology of China of the Chinese Academy of Sciences, in collaboration with Assoc. Prof. Wang Zhi from Sun Yat-sen University, discovered the long-range skin Josephson supercurrent across a van der Waals ferromagnet.

They bridged two spin-singlet superconductors NbSe2 (S) by constructing the van der Waals metal Fe3GeTe2 (F), and observed long-range supercurrent in the lateral Josephson junction (S/F/S) for the first time, which exhibits astonishing skin characteristics.

Ferromagnetism and superconductivity are two antagonistic macroscopic orderings. When the singlet supercurrent enters the ferromagnet, rapid decoherence of the Cooper pairs will be triggered.

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An unsettling report released barely a year ago painted a grim picture of the plastics industry—only about 5 percent of the 46 million annual tons of plastic waste in the US makes it to recycling facilities. The number is even more depressing after realizing that is roughly half of experts’ previous estimates. But if all that wasn’t enough, new information throws a heaping handful of salt on the wound: of the plastic that does make it to recycling, a lot of it is still released into the world as potentially toxic microplastics.

According to the pilot study recently published in the Journal of Hazardous Materials Advances focused on a single, modern facility, recycling plants’ wastewater contains a staggering number of microplastic particles. And as Wired explained on Friday, all those possibly toxic particulates have to go somewhere, i.e. potentially city water systems, or the larger environment.

The survey focusing on one new, unnamed facility examined its entire recycling process. This involves sorting, shredding, and melting plastics down into pellets. During those phases of recycling, however, the plastic waste is washed multiple times, which subsequently sheds particles smaller than 5 millimeters along the way. Despite factoring in the plant’s state-of-the-art filtration system designed to capture particulates as tiny as 50 microns, the facility still produced as many as 75 billion particles per cubic meter of wastewater.

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Chemists have made an iridescent, plant-based film that gets cooler in sunlight.

The material, which comes in a range of shining colours, could one day coat buildings and cars, lowering the need for air conditioning.

The film exhibits a smart property: called passive daytime radiative cooling, or PDRC, it doesn’t absorb much light, and it radiates heat out at a wavelength that escapes the atmosphere and zooms straight into space.

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Year 2013 😗😁

Shamees Aden, a British designer and scientist, has come up with a concept for a pair of self-repairing shoes of synthetic protocell materials.

Protocells are molecules that on their own are not alive, but when used with other types of protocells can mimic the properties of living organisms. They react to heat, light and pressure like live cells.

Aden’s concept for the shoes is that they could be 3D printed to the exact size of the wearer and when worn the shoes would react to heat and pressure to grow and expand in pressure points where more cushioning is needed. They would be kept in protocell fluid overnight to regenerate.

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An international team of scientists has imaged and analyzed THz waves that propagate in the form of plasmon polaritons along thin anisotropic semiconductor platelets with wavelengths reduced by up to 65 times compared to THz waves in free space.

What’s even more intriguing is that the wavelengths vary with the direction of propagation. Such THz waves can be applied for probing fundamental material properties at the nanometer scale and pave the way to the development of ultra-compact on-chip THz devices. The work has been published in Nature Materials.

Polaritons are hybrid states of light and matter that arise from the coupling of light with matter excitations. Plasmon and phonon polaritons are among the most prominent examples, formed by the coupling of light to collective electron oscillations and crystal lattice vibrations, respectively.

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