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Archive for the ‘particle physics’ category: Page 450

Nov 29, 2018

MIT Studies Micro-Impacts at 100 Million Frames Per Second

Posted by in categories: particle physics, space travel

Engineers know that tiny, super-fast objects can cause damage to spacecraft, but it’s been difficult to understand exactly how the damage happens because the moment of impact is incredibly brief. A new study from MIT seeks to reveal the processes at work that produce microscopic craters and holes in materials. The hope is that by understanding how the impacts work, we might be able to more durable materials.

Accidental space impacts aren’t the only place these mechanisms come into play. There are also industrial applications on Earth like applying coatings, strengthening metallic surfaces, and cutting materials. A better understanding of micro-impacts could also make these processes more efficient. Observing such impacts was not easy, though.

For the experiments, the MIT team used tin particles about 10 micrometers in diameter accelerated to 1 kilometer per second. They used a laser system to launch the projectile that instantly evaporates a surface material and ejects the particles, ensuring consistent timing. That’s important because the high-speed camera pointed at the test surface (also tin) needed specific lighting conditions. At the appointed time, a second laser illuminated the particle allowing the camera to follow the impact at up to 100 million frames per second.

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Nov 28, 2018

Ultracold quantum mix

Posted by in categories: particle physics, quantum physics

The experimental investigation of ultracold quantum matter makes it possible to study quantum mechanical phenomena that are otherwise inaccessible. A team led by the Innsbruck physicist Francesca Ferlaino has now mixed quantum gases of two strongly magnetic elements, erbium and dysprosium, and created a dipolar quantum mixture.

A few years ago, it seemed unfeasible to extend the techniques of atom manipulation and deep cooling in the ultracold regime to many-valence-electron atomic species. The reason is the increasing complexity in the atomic spectrum and the unknown scattering properties. However, a team of researchers, led by Ben Lev at Stanford University and an Austrian team directed by Francesca Ferlaino at the University of Innsbruck demonstrated degeneracy of rare-earth species. Ferlaino’s group focused the on and developed a powerful, yet surprisingly simple approach to produce a Bose-Einstein condensate.

“We have shown how the complexity of atomic physics can open up new possibilities,” says Ferlaino. Magnetic species are an ideal platform to create dipolar quantum matter, in which particles interact with each other via a long-range and orientation dependent interaction as little quantum magnets.

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Nov 27, 2018

First sun-dimming experiment will test a way to cool Earth

Posted by in category: particle physics

Researchers plan to spray sunlight-reflecting particles into the stratosphere, an approach that could ultimately be used to quickly lower the planet’s temperature.

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Nov 26, 2018

Quantum computing at scale: Scientists achieve compact, sensitive qubit readout

Posted by in categories: computing, particle physics, quantum physics

Professor Michelle Simmons’ team at UNSW Sydney has demonstrated a compact sensor for accessing information stored in the electrons of individual atoms—a breakthrough that brings us one step closer to scalable quantum computing in silicon.

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Nov 26, 2018

Environment turns molecule into a switch

Posted by in category: particle physics

It looks like a cross with four arms of equal length that have a central atom at their intersection. All atoms are arranged in one plane so that the molecule is absolutely planar – at least in the normal state.

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Nov 26, 2018

Scientists Hunt for A Seeming Paradox: A Magnet With Only One Pole

Posted by in category: particle physics

For centuries, physicists have hunted for particles with a single north or south pole to help put together their theory of everything. They may be closer than ever.

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Nov 23, 2018

Riccardo Levi-Setti, Holocaust survivor who uncovered trilobites and subatomic particles, dies at 91

Posted by in category: particle physics

While on the run, he also developed a lifelong interest in fossils — possibly the result of scrambling across a fossil-filled rock pile while evading German patrols, his son said — and in physics.

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Nov 23, 2018

Researchers Just Found a Way to Turn CO2 Into Plastic With Unprecedented Efficiency

Posted by in categories: particle physics, sustainability

Researchers have developed catalysts that can convert carbon dioxide—the main cause of global warming—into plastics, fabrics, resins, and other products.

The electrocatalysts are the first materials, aside from enzymes, that can turn carbon dioxide and water into carbon building blocks containing one, two, three, or four carbon atoms with more than 99 percent efficiency.

Two of the products—methylglyoxal (C3) and 2,3-furandiol (C4)—can be used as precursors for plastics, adhesives, and pharmaceuticals. Toxic formaldehyde could be replaced by methylglyoxal, which is safer.

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Nov 23, 2018

Meet Dawn Shaughnessy, the Real-Life Alchemist Who Expanded the Periodic Table

Posted by in categories: chemistry, particle physics

The periodic table is chemistry’s holy text. Not only does it list all of the tools at chemists’ disposal, but its mere shape—where these elements fall into specific rows and columns—has made profound predictions about new elements and their properties that later came true. But few chemists on Earth have a closer relationship with the document than Dawn Shaughnessy, whose team is partially responsible for adding six new elements to table’s ranks.

Shaughnessy leads a team of real-life alchemists. You might be familiar with alchemy as a medieval European practice where mystics attempted to transmute elements into more valuable ones. But rather than turn the element lead into gold, Shaughnessy and her team turned plutonium into flerovium.

Shaughnessy’s parents encouraged her to pursue science from a young age—her father was an engineer, and she had an electronics kit as well as a chemistry set as a child. She’d first thought about doing orthopedic research but didn’t want to cut people open, she explained to me, and chemistry was a natural fit. But when she arrived at the University of California, Berkeley as an undergraduate, she learned that chemistry could be more than just mixing liquids in beakers. She could create the atoms themselves.

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Nov 21, 2018

The microscope revolution that’s sweeping through materials science

Posted by in categories: particle physics, science

Scientists can’t study what they can’t measure — as David Muller knows only too well. An applied physicist, Muller has been grappling for years with the limitations of the best imaging tools available as he seeks to probe materials at the atomic scale.

One particularly vexing quarry has been ultra-thin layers of the material molybdenum disulfide, which show promise for building thin, flexible electronics. Muller and his colleagues at Cornell University in Ithaca, New York, have spent years peering at MoS2 samples under an electron microscope to discern their atomic structures. The problem was seeing the sulfur atoms clearly, Muller says. Raising the energy of the electron beam would sharpen the image, but knock atoms out of the MoS2 sheet in the process. Anyone hoping to say something definitive about defects in the structure would have to guess. “It would take a lot of courage, and maybe half the time, you’d be right,” he says.

This July, Muller’s team reported a breakthrough. Using an ultra-sensitive detector that the researchers had created and a special method for reconstructing the data, they resolved features in MoS2 down to 0.39 angstroms, two and a half times better than a conventional electron microscope would achieve. (1 Å is one-tenth of a nanometre, and a common measure of atomic bond lengths.) At once, formerly fuzzy sulfur atoms now showed up clearly — and so did ‘holes’ where they were absent. Ordinary electron microscopy is “like flying propeller planes”, Muller says. “Now we have a jet.”

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