Category: applied physics

An evocative image, no doubt.

Via Phys.org: New green technology generates electricity ‘out of thin air’

Caption:

Graphic image of a thin film of protein nanowires generating electricity from atmospheric humidity. UMass Amherst researchers say the device can literally make electricity out of thin air.

Credit: UMass Amherst/Yao and Lovley labs

Fragile topology: Two new studies explain the strange electron flow

in future materials.

“…topological insulators have an uncommon property:

their interiors are insulators—where electrons cannot flow—but their surfaces are perfect conductors, where electrons flow without resistance […]

That was the picture until the discovery two years ago that some topological materials are actually unable to conduct current on their surface, a phenomenon that earned the name fragile topology.”

Caption: “

Remarkable materials known as topological insulators have a fragile side. Credit: Zhi-Da Song, Princeton University.

Via Phys.org´

(arXiv preprintPDF)

Researchers build a particle accelerator that fits on a chip

Caption. This image, magnified 25,000 times, shows a section of a prototype accelerator-on-a-chip. The segment shown here are one-tenth the width of a human. The oddly shaped gray structures are nanometer-sized features carved in to silicon that focus bursts of infrared laser light, shown in yellow and purple, on a flow of electrons through the center channel. As the electrons travel from left to right, the light focused in the channel is carefully synchronized with passing particles to move them forward at greater and greater velocities. By packing 1,000 of these acceleration channels onto an inch-sized chip, Stanford researchers hope to create an electron beam that moves at 94 percent of the speed of light, and to use this energized particle flow for research and medical applications.

Credit: Neil Sapra

Via Phys.org

Paper: 

On-chip integrated laser-driven particle accelerator (Science, arXiv preprintPDF)

Precision vs. accuracy

Imagine an archer who has shot ten arrows. In this scenario, precision is a measurement of the arrows’ positions relative to each other and accuracy is a measurement of their positions relative to the bullseye. A precise archer isn’t necessarily an accurate one, and vice versa.

The precision of an archer is analogous to a concept called clock stability. If one thinks of each tick of the clock as a shot and hitting the bullseye as keeping the exact right time between every tick, then a precise but not accurate clock would consistently tick either slower or faster than the desired amount of time. On the other hand, an accurate but imprecise clock would tick sometimes faster and sometimes slower, but the accumulated errors would average out somewhat over time.

Via Inside Science: Why Do We Need Super Accurate Atomic Clocks?

The stunning emergence of a new type of superconductivity with the mere twist of a carbon sheet.

It’s exceptionally difficult to twist two sheets of graphene exactly 1.1 degrees out of alignment. But this “magic angle” leads to extraordinary effects.

Credits: Olena Shmahalo/Quanta Magazine

Via Quanta Magazine

A 100-hour MRI scan captured the most detailed look yet at a whole human brain (Science News)

Paper (bioRxiv.org): 7 Tesla MRI of the ex vivo human brain at 100 micron resolution 

Maps of tumours grown in mice. (Credit: Arvind Pathak)

Via Physics World / Biophysics

M87 Black Hole Size Comparison

xkcd

Alt/title text:

“I think Voyager 1 would be just past the event horizon, but slightly less than halfway to the bright ring.”

More:

– Explain xkcd

– Focus on the First Event Horizon Telescope Results – The Astrophysical Journal Letters – IOPscience

– NASA news: Black Hole Image Makes History; NASA Telescopes Coordinated Observations

NSF Media resources

– Event Horizon Telescope (Official website)

Robotic bees are joining the International Space Station

Via Tech Xplore

Astrobee is “a compact one-foot-cube of a robot in development at NASA’s Ames Research Center in Silicon Valley. This robot is designed to work autonomously without astronaut supervision, or to be remotely operated by mission controllers.

NASA captures unprecedented images of supersonic shockwaves

The ability to capture such detailed images of shockwaves will be “crucial” to NASA’s development of the X-59, the agency said, an experimental supersonic plane it hopes will be able to break the sound barrier with just a rumble instead of a sonic boom.

Via Phys.org