Lifeboat Foundation

Like all metals, silver, copper, and gold are conductors. Electrons flow across them, carrying heat and electricity. While gold is a good conductor under any conditions, some materials have the property of behaving like metal conductors only if temperatures are high enough; at low temperatures, they act like insulators and do not do a good job of carrying electricity. In other words, these unusual materials go from acting like a chunk of gold to acting like a piece of wood as temperatures are lowered. Physicists have developed theories to explain this so-called metal-insulator transition, but the mechanisms behind the transitions are not always clear.

“In some cases, it is not easy to predict whether a material is a metal or an insulator,” explains Caltech visiting associate Yejun Feng of the Okinawa Institute for Science and Technology Graduate University. “Metals are always good conductors no matter what, but some other so-called apparent metals are insulators for reasons that are not well understood.” Feng has puzzled over this question for at least five years; others on his team, such as collaborator David Mandrus at the University of Tennessee, have thought about the problem for more than two decades.

Now, a new study from Feng and colleagues, published in Nature Communications, offers the cleanest experimental proof yet of a metal-insulator transition theory proposed 70 years ago by physicist John Slater. According to that theory, magnetism, which results when the so-called “spins” of electrons in a material are organized in an orderly fashion, can solely drive the metal-insulator transition; in other previous experiments, changes in the lattice structure of a material or electron interactions based on their charges have been deemed responsible.

Scientists in South Korea have made a breakthrough in battery research that could help us bust through a key bottleneck in energy storage. The team’s advance overcomes a technical issue that has held back highly promising lithium-metal battery architecture and could pave the way for batteries with as much as 10 times the capacity of today’s devices.

The reason lithium-metal batteries hold so much promise is because of the excellent energy density of pure lithium metal. Scientists hope to swap out the graphite used for the anode in today’s lithium batteries for this “dream material,” though this comes with some complicated problems to solve.

One of the key issues relates to needle-like structures called dendrites, which form on the anode surface as the battery is charged. These penetrate the barrier between the anode and the battery’s other electrode, the cathode, and quickly cause the battery to short-circuit, fail, or even catch fire.

The dynamics of water molecules at interfaces controls natural and artificial processes, but experimental investigations have been challenging. Here the authors investigate water molecules on a graphene surface using helium spin-echo spectroscopy, and reveal a regime where freely mobile molecules undergo strong repulsive mutual interactions which inhibit ice nucleation.

Enlight uses light polarization to maximize resolution and to find critical defects in half the time of the typical optical scanner. The scanner for the first time will capture both direct light bouncing off the wafer surface, and scattered light, known as “brightfield” and “greyfield,” respectively. That’s like scanning two things in one pass, cutting in half the time required.

In the concrete jungle of Singapore, some people are ditching the comforts of the air-conditioned offices and opting to get their hands dirty instead. CNBC’s Nessa Anwar meets some of the trailblazers marrying traditional jobs with technology.
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Earth’s oldest known material: Some zircons from Australia date back more than 4 billion years.

Crystals of the mineral zircon are rugged enough to survive the most violent geologic events.

Plastic pollution and other ocean debris are a complex global environmental problem. Every year, ten million tons of plastic are estimated to be mismanaged, resulting in entry into the ocean, of which half will float initially. Yet, only 0.3 million tons of plastic can be found floating on the surface of the ocean. Where has the rest of the plastic gone?

The key mechanisms for plastic transport are currents, wind, and waves. Currents and wind transport ocean debris in a straightforward manner like the forces on a sailing boat. However, ocean waves predominantly move objects in circular-like orbits. The orbits do not quite close, resulting in a so-called Stokes drift in the direction in which the waves travel.

A joint team from the Universities of Oxford, Plymouth, Edinburgh, Auckland and TU Delft have investigated how waves transport floating ocean debris while including, for the first time, the effects of an object’s size, buoyancy, and inertia on its transport. Their results are published in the Journal of Fluid Mechanics.

Summary: The reactivation of learned material during slow oscillation/sleep spindle complexes, and the precision of SO-spindle coupling predicts how strong a memory will be reactivated in the brain.

Source: University of Birmingham.

While we sleep, the brain produces particular activation patterns. When two of these patterns – slow oscillations and sleep spindles – gear into each other, previous experiences are reactivated. The stronger the reactivation, the clearer will be our recall of past events, a new study reveals.

Our oceans are filled with tiny pieces of plastic. These tiny devices can break them down.