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Category: materials – Page 201

Scientists take control of magnetism at the microscopic level

Atoms in magnetic materials are organized into regions called magnetic domains. Within each domain, the electrons have the same magnetic orientation. This means their spins point in the same direction. “Walls” separate the magnetic domains. One type of wall has spin rotations that are left-or right-handed, known as having chirality. When subjected to a magnetic field, chiral domain walls approach one another, shrinking the magnetic domains.

Researchers have developed a magnetic material whose thickness determines whether chiral domain walls have the same or alternating handedness. In the latter case, applying a leads to annihilation of colliding domain walls. The researchers combined and electron microscopy to characterize these internal, microscopic features, leading to better understanding of the magnetic behavior.

An emerging field of technology called spintronics involves processing and storing information by harnessing an electron’s spin instead of its charge. The ability to control this fundamental property could unlock new possibilities for developing electronic devices. Compared to current technology, these devices could store more information in less space and operate at higher speeds with less energy consumption.

New hafnium polyhydrides superconductive above 80 K

The discovery of high temperature superconductors in polyhydrides encourages searching for new types of hydrogen rich superconductors. Most of experimentally reported high Tc polyhydride superconductors are binary hydrides of main group elements, rare earth metals (La, Y etc.) or alkali earth metal (Ca).

Prof. Jin team at Institute of Physics of Chinese Academy of Sciences (IOPCAS) recently discovered new hafnium polyhydrides using synergetic techniques based on diamond anvil cell in combination with in situ laser heating during a search for new types of hydrogen rich superconducting materials.

“The hafnium polyhydrides are synthesized at 243GPa and 2000 K high pressure high temperature conditions and exhibits superconductivity with Tc ~83 K at 243GPa,” explained coauthor Xiancheng Wang who is a professor at IOPCAS. The upper critical field was estimated to be ~24 Tesla while the Ginzburg Landau superconducting coherent length obtained is ~37Å.

Anti-laser can make any object suck in light

Inserting any material into a special maze of mirrors and lenses can make it absorb light perfectly. This approach could be used to detect faint starlight or for charging faraway devices with lasers.

Ori Katz at the Hebrew University of Jerusalem in Israel and his colleagues created an almost perfect absorber of light by building an “anti-laser”.

In a laser, light bounces between mirrors until it becomes amplified enough to exit the device in a concentrated beam. In an “anti-laser”, says co-author Stefan Rotter at Vienna University of Technology in Austria, light enters the device then gets stuck in an inescapable series of bounces within it.

Nile waterscapes facilitated the construction of the Giza pyramids during the 3rd millennium BCE

Ancient engineers might have built a canal on the Nile.

No one has solved the mystery of the Giza pyramids for centuries. Although archaeologists and scientists have tried to reveal how they were made over the years, it is difficult to say the “exact method” for sure. However, very recently, an idea has been put forward by researchers about how the pyramids were built.

According to a recent study — published in PNAS in August. 29 —the pyramids of Giza may have been built using a former arm of the Nile River. This river branch would have served as a navigable route for the transportation of goods not previously known.

The pyramids of Giza constitute one of the world’s most iconic cultural landscapes and have fascinated humanity for thousands of years. Indeed, the Great Pyramid of Giza (Khufu Pyramid) was one of the Seven Wonders of the Ancient World. It is now accepted that ancient Egyptian engineers exploited a former channel of the Nile to transport building materials and provisions to the Giza plateau. However, there is a paucity of environmental evidence regarding when, where, and how these ancient landscapes evolved. New palaeoecological analyses have helped to reconstruct an 8,000-year fluvial history of the Nile in this area, showing that the former waterscapes and higher river levels around 4,500 years ago facilitated the construction of the Giza Pyramid Complex.

The Ocean Cleanup is a non-profit project developing and scaling technologies to rid the oceans of plastic

Our innovative ocean cleaning system is already removing plastic from the Pacific Ocean. Combined with our Interceptor river solutions deployed around the world, we aim to reduce floating ocean plastic by 90% by 2040.

Trillions of pieces of plastic float on the surface of our oceans, damaging habitats and contaminating food chains; a problem forecast to worsen exponentially as the stream of plastic flowing into the ocean from rivers increases. We address the plastic problem with a dual strategy: removing plastic that is already polluting the oceans, while also intercepting plastic in rivers to prevent it reaching the ocean and adding to the problem.

Throughout 2021 and 2022, our ocean cleaning system has been harvesting plastic from the Great Pacific Garbage Patch (GPGP), estimated to contain around 100,000,000 kilograms of plastic. Each branch of this strategy is essential to efficiently rid the oceans of plastic.

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