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Category: materials – Page 229

Astronomers have used NASA’s Chandra X-ray Observatory to record material blasting away from the site of an exploded star at speeds faster than 20 million miles per hour. This is about 25,000 times faster than the speed of sound on Earth.

Kepler’s supernova remnant is the debris from a detonated star that is located about 20,000 light years away from Earth in our Milky Way galaxy. In 1604 early astronomers, including Johannes Kepler who became the object’s namesake, saw the supernova explosion that destroyed the star.

We now know that Kepler’s supernova remnant is the aftermath of a so-called Type Ia supernova, where a small dense star, known as a white dwarf, exceeds a critical mass limit after interacting with a companion star and undergoes a thermonuclear explosion that shatters the white dwarf and launches its remains outward.

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Circa 2012

Back in 1871, James Clerk Maxwell predicted that light exerts a force on any surface it hits. This radiation pressure was experimentally discovered some 30 years later and has since emerged as a hugely important force that is now exploited in systems such as solar sails and laser cooling.

Today, John Zhang and buddies at the University of Southampton in the UK go one better. These guys predict that a far more powerful optical force can exist between a metal or dielectric plate and a metamaterial, a substance with optical properties that have been engineered to control light in specific ways.

Metamaterials can be designed so they allow tiny oscillations of electrons called plasmons to exist on their surfaces. The oscillations are tiny–measured in nanometres, that’s about the same as the wavelength of visible light.

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Technology that can convert salty seawater or brackish water into safe, clean drinking water has the potential to transform millions of lives across the globe, which is why so many scientists are busy working on projects to do just that.

Now, a new innovation developed by scientists in Australia could be the most promising one yet, with researchers using metal-organic framework compounds (or MOFs) together with sunlight to purify water in just half an hour, using a process that’s more efficient than existing techniques.

It’s cheap, it’s stable, it’s reusable, and it produces water that meets the World Health Organisation (WHO) standards for desalination. Around 139.5 litres (nearly 37 gallons) of clean water can be produced per day from a kilogram (2.2 pounds) of MOF material, based on early testing.

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Hubble Finds That Betelgeuse’s Mysterious Dimming Is Due to a Traumatic Outburst

Observations by NASA ’s Hubble Space Telescope are showing that the unexpected dimming of the supergiant star Betelgeuse was most likely caused by an immense amount of hot material ejected into space, forming a dust cloud that blocked starlight coming from Betelgeuse’s surface.

Hubble researchers suggest that the dust cloud formed when superhot plasma unleashed from an upwelling of a large convection cell on the star’s surface passed through the hot atmosphere to the colder outer layers, where it cooled and formed dust grains. The resulting dust cloud blocked light from about a quarter of the star’s surface, beginning in late 2019. By April 2020, the star returned to normal brightness.

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Novel two-dimensional materials are currently a hot research topic around the world. Of special interest are van der Waals heterostructures, which are made up of individual layers of different materials held together by van der Waals forces. The interactions between the different layers can give the resulting material entirely new properties.

Double layer unlocks crucial properties

There are already van der Waals heterostructures that absorb up to 100 percent of light. Single-layers of molybdenum disulfide offer absorption capacities in this range. When light is absorbed, an electron vacates its original position in the , leaving behind a positively charged hole. The electron moves to a higher energy level, known as the conduction band, where it can move freely.

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MEDAN, Indonesia — Indonesia’s rumbling Mount Sinabung erupted Monday, sending a column of volcanic materials as high as 16,400 feet into the sky and depositing ash on villages.

It is the second eruption since Saturday after the volcano sat dormant for more than a year.

Falling grit and ash accumulated up to 2 inches in already abandoned villages on the volcano’s slopes, said Armen Putra, an official at the Sinabung monitoring post on Sumatra Island.

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Imagine plugging in to your brick house.

Red bricks—some of the world’s cheapest and most familiar building materials—can be converted into storage units that can be charged to hold electricity, like a battery, according to new research from Washington University in St. Louis.

Brick has been used in walls and buildings for thousands of years, but rarely has been found fit for any other use. Now, chemists in Arts & Sciences have developed a method to make or modify “smart bricks” that can store energy until required for powering devices. A proof-of-concept published Aug. 11 in Nature Communications shows a brick directly powering a green LED light.

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Scientists at the University of Bath have taken an important step towards understanding the interaction between layers of atomically thin materials arranged in stacks. They hope their research will speed up the discovery of new, artificial materials, leading to the design of electronic components that are far tinier and more efficient than anything known today.

Smaller is always better in the world of electronic circuitry, but there’s a limit to how far you can shrink a silicon component without it overheating and falling apart, and we’re close to reaching it. The researchers are investigating a group of atomically thin materials that can be assembled into stacks. The properties of any final material depend both on the choice of raw materials and on the angle at which one layer is arranged on top of another.

Dr. Marcin Mucha-Kruczynski who led the research from the Department of Physics, said: “We’ve found a way to determine how strongly atoms in different layers of a stack are coupled to each other, and we’ve demonstrated the application of our idea to a structure made of .”

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