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Category: materials – Page 67

Anthropogenic plastic pollution is often experienced through evocative images of marine animals caught in floating debris, yet its reach is far more expansive. The polar regions of the Arctic and Antarctica are increasingly experiencing the impacts of plastic reaching floating ice and land, not solely as larger macroplastics (>5 cm), but as microplastics (0.1 µm—5 mm) and nanoplastics (<0.1 µm) that may be carried vast distances from their source or be ingested in more populated areas during seasonal migration.

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Using sugarcane waste as bricks for construction.

Architecture studio Grimshaw and the University of East London have collaborated to create Sugarcrete, a biomaterial construction block with an interlocking shape made from the sugarcane by-product bagasse.

Sugarcrete was developed to be a low-cost and low-carbon reusable construction-material alternative to brick and concrete.

The concept, design and fabrication of the material were led by staff and fellows of the University of East London (UEL), including senior architecture lecturer Armor Gutierrez Rivas, Sustainability Research Institute co-director Alan Chandler and research fellow Bamdad Ayati.

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Harvard researchers say they have developed a programmable metafluid they are calling an ‘intelligent liquid’ that contains tunable springiness, adjustable optical properties, variable viscosity, and even the seemingly magical ability to shift between a Newtonian and non-Newtonian fluid.

The team’s exact formula is still a secret as they explore potential commercial applications. However, the researchers believe their intelligent liquid could be used in anything from programmable robots to intelligent shock absorbers or even optical devices that can shift between transparent and opaque states.

“We are just scratching the surface of what is possible with this new class of fluid,” said Adel Djellouli, a Research Associate in Materials Science and Mechanical Engineering at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) and the first author of the paper. “With this one platform, you could do so many different things in so many different fields.”

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Many biological structures form through the self-assembly of molecular building blocks. A new theoretical study explores how the shape of these building blocks can affect the formation rate [1]. The simplified model shows that hexagonal blocks can form large structures much faster than triangular or square blocks. The results could help biologists explain cellular behavior, while also giving engineers inspiration for more efficient self-assembly designs.

Certain viruses and cellular structures are made from self-assembling pieces that can be characterized by geometrical shapes. For example, some types of bacteria host carboxysomes, which are icosahedral (20-face) compartments built up from self-assembling hexagonal and pentagonal subunits.

To investigate the role of shape, Florian Gartner and Erwin Frey from Ludwig Maximilian University of Munich simulated self-assembly of two-dimensional structures with three types of building blocks: triangles, squares, and hexagons. The model assumed that the blocks bind along their edges, but these interactions are reversible, meaning that the resulting structures can fall apart before growing very large. Gartner and Frey found that certain shapes were better than others at assembling into larger structures, as they tended to form intermediate structures with more bonds around each block. In particular, hexagonal blocks were the most efficient building material, forming 1000-piece structures at a rate that was 10,000 times faster than triangular blocks.

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Graphene is the setting for the first demonstration of relativistic electrons’ paradoxical ability to whiz through a barrier, provided the barrier is high enough.

If an electron in a material has a speed that is independent of its energy and if it encounters a barrier head on, it can tunnel straight through. Derived by theorist Oskar Klein in 1929, this counterintuitive finding remained little tested in the lab because it is hard to make electrons approach a barrier head on and to stop them scattering off the edges of the sample. Now Mirza Elahi of the University of Virginia and his collaborators have observed evidence of Klein tunneling in monolayer graphene. What’s more, they also observed the opposite effect, anti-Klein tunneling, in bilayer graphene. In anti-Klein tunneling, head-on electrons do not tunnel at all, while others approaching the barrier at an intermediate angle do [1].

Graphene’s hexagonal lattice can be thought of as two identical interpenetrating triangular sublattices. One consequence of that view is that graphene’s charge carriers—electrons that hop between the two sublattices—behave as if massless and relativistic at low energies. Another consequence is that the two sublattices bestow on the electrons a chiral property, pseudospin, that resembles spin, which controls the nature of the transmission across the barrier.

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The last time you dropped a favorite mug or sat on your glasses, you may have been too preoccupied to take much notice of the intricate pattern of cracks that appeared in the broken object. But capturing the formation of such patterns is the specialty of John Kolinski and his team at the Laboratory of Engineering Mechanics of Soft Interfaces (EMSI) in EPFL’s School of Engineering. They aim to understand how cracks propagate in brittle solids, which is essential for developing and testing safe and cost-effective composite materials for use in construction, sports, and aerospace engineering.

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Dielectric metasurfaces, known for their low loss and subwavelength scale, are revolutionizing optical systems by allowing multidimensional light modulation. Researchers have now innovated in this field by developing a liquid crystal-based dielectric metasurface that streamlines manufacturing and enhances device performance.

Dielectric metasurfaces represent one of the cutting-edge research and application directions in the current optical field. They not only possess the advantage of low loss but also enable the realization of device thicknesses at subwavelength scales. Moreover, they can freely modulate light in multiple dimensions such as amplitude, phase, and polarization. This capability, which traditional optics lacks, holds significant importance for the integration, miniaturization, and scaling of future optical systems. Consequently, dielectric metasurfaces have attracted increasing industrial attention.

In this study, Professor Daping Chu’s team at the University of Cambridge developed a novel liquid crystal-based tunable dielectric metasurface. By leveraging the dielectric metasurface’s inherent alignment effect on liquid crystals on top of its electrically controllable properties, the need for liquid crystal alignment layer materials and related processes is eliminated, thus saving device manufacturing time and costs. This has practical implications for devices such as liquid crystal on silicon (LCoS).

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Many of us have seen photos of and read stories about robots working on the production floor in factories, speeding up old-school assembly lines to build products more quickly. And while the robotics trend in manufacturing is continuing to grow, that’s not the only way technology (including artificial intelligence) and automation are impacting the industry.

From enhancing worker safety to more efficiently moving goods and materials from point A to point B, automation is making its mark on the manufacturing industry, and tech experts expect even more changes and improvements in the near future. Below, 17 members of Forbes Technology Council discuss specific manufacturing tasks that are (or soon will be) handled more efficiently, safely and productively by technology and automation.

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