Lifeboat Foundation

Scientists have examined the performance of pure boron, boron carbide, high-density carbon and boron nitride ablators—the material that surrounds a fusion fuel and couples with the laser or hohlraum radiation in an experiment—in the polar direct drive exploding pusher (PDXP) platform, which is used at the National Ignition Facility (NIF). The platform uses the polar direct drive configuration to drive high ion temperatures in a room-temperature capsule and has potential applications for plasma physics studies and as a neutron source.

The key findings of the work, featured in High Energy Density Physics, show that these alternate ablators do not improve the symmetry of the PDXP implosion, according to lead author Heather Whitley, associate program director for High Energy Density Science in the Fundamental Weapon Physics section at Lawrence Livermore National Laboratory (LLNL).

“While our simulations predict that the platform is not amenable to the electron-ion coupling measurements due to a lack of implosion symmetry, the alternate materials do enable better coupling between the laser and capsule,” she said. “We plan to test those predicted impacts on future neutron source experiments.”

While the remaining supersonic contenders duke it out to bring faster jets to market, private jet operators are doing their best to address the business traveler’s appetite for speed with aircraft that are as close to the sound barrier as they can be without actually breaking it, which poses all kinds of environmental issues.

With the news that supersonic planemaker Aerion has unexpectedly folded, is the dream of a successor to Concorde running out of fuel?

Everything is weird on the Sun, where things are not where you’d expect.

This spike in temperature, despite the increased distance from the Sun’s main energy source, has been observed in most stars and represents a fundamental puzzle that astrophysicists have mulled over for decades.

Continue reading “Scientists solve an 80-year-old paradox about the Sun” »

Thermoelectric (TE) conversion offers carbon-free power generation from geothermal, waste, body or solar heat, and shows promise to be the next-generation energy conversion technology. At the core of such TE conversion, there lies an all solid-state thermoelectric device which enables energy conversion without the emission of noise, vibrations, or pollutants. To this, a POSTECH research team proposed a way to design the next-generation thermoelectric device that exhibits remarkably simple manufacturing process and structure compared to the conventional ones, while displaying improved energy conversion efficiency using the spin Seebeck effect (SSE).

A POSTECH joint research team—led by Professor Hyungyu Jin and Ph.D. candidate Min Young Kim of the Department of Mechanical Engineering with Professor Si-Young Choi of the Department of Materials Science and Engineering—has succeeded in designing a highly efficient thermoelectric device by optimizing the properties of both the interior and surface of the magnetic material that makes up the SSE thermoelectric device. This is a pioneering study to show the possibility of fabricating a next-generation thermoelectric device by utilizing the SSE, which has remained in fundamental research. These research findings were recently published in the online edition of Energy and Environmental Science, an international academic journal in the field of energy.

Conventional TE devices rely on the charge Seebeck effect, a thermoelectric effect wherein a charge current is generated in the direction parallel to an applied temperature gradient in a solid material. This longitudinal geometry complicates the device structure and limits manufacturing such TE devices.

Signals can be amplified by an optimum amount of noise, but stochastic resonance is a fragile phenomenon. Researchers at AMOLF were the first to investigate the role of memory for this phenomenon in an oil-filled optical microcavity. The effects of slow non-linearity (i.e. memory) on stochastic resonance were never considered before, but these experiments suggest that stochastic resonance becomes robust to variations in the signal frequency when systems have memory. This has implications in many fields of physics and energy technology. In particular, the scientists numerically show that introducing slow nonlinearity in a mechanical oscillator harvesting energy from noise can increase its efficiency tenfold. They have published their findings in Physical Review Letters on May 27th.

It is not easy to concentrate on a difficult task when two people are having a loud discussion right next to you. However, complete silence is often not the best alternative. Whether it is some soft music, remote traffic noise or the hum of people chatting in the distance, for many people, an optimum amount of noise enables them to concentrate better. “This is the human equivalent of stochastic resonance,” says AMOLF group leader Said Rodriguez. “In our scientific labs, stochastic resonance happens in nonlinear systems that are bistable. This means that, for a given input, the output can switch between two possible values. When the input is a periodic signal, the response of a non-linear system can be amplified by an optimum amount of noise using the stochastic resonance condition.”

Paradoxically, Jupiter’s ice-covered moon of Europa may have seafloor volcanoes capable of generating enough chemical energy and heat to support life, says new paper.

Researchers have also long been chasing lithium-air batteries that could realize a huge jump in energy density. And beyond lithium, there are other entirely different chemistries in development out there. At some point, one of them should click for one application or another.

Lithium-ion or not, an explosion of grid-scale battery installations is coming as prices continue to fall. The nascent art of lithium-ion battery recycling is also sure to mature and expand, improving the sustainability of these batteries by recovering and resetting their chemical building blocks.

Adopt cold-fusion-like skepticism of any of these future-looking statements as you please, but today’s batteries aren’t those of 20 or even 10 years ago. The same thing is bound to be true in another 10 years—even if that progress doesn’t come in a single, giant leap with global fanfare.

Zinc-air batteries (ZABs) are among the most promising next-generation battery technologies due to their many advantageous characteristics. Most notably, these batteries have unique half-open structures, a significant theoretical energy density (1086 and 1370 Wh kg⁻¹ when including and excluding oxygen, respectively), flexible electrodes and an inherently aqueous electrolyte. Moreover, in contrast with other materials used in batteries, Zinc (Zn) is less harmful for the environment and more abundant.

Researchers at Hanyang University in South Korea recently designed a new type of zinc-air pouch cell that can outperform other commercially available battery technologies. These pouch cells, presented in a paper published in Nature Energy, use (101)-facet copper phosphosulfide [CPS(101)] as a cathode, anti-freezing chitosan-biocellulosics as super-ionic conductor electrolytes, and patterned Zn as the anode.

“Previous ZABs employing liquid (6 M KOH) electrolytes failed because of the sluggish kinetics for the oxygen reduction and evolution reactions (ORR/OER) and irreversibility of Zn accompanying the parasitic reactions over wide temperatures,” Jung-Ho Lee, one of the researchers who carried out the study, told Tech Xplore. “This feature inspired us to develop solid-state electrolytes, such as functionalized biocellulose, capable of transferring OH^- ions effectively without parasitic reactions.”

Israel’s Aquarius Engines this week gave the world a first look at the tiny hydrogen engine it hopes can supplant gas engine-generators and hydrogen fuel cells in future electrified vehicles. Weighing just 22 lb (10 kg), the simple engine uses a single moving piston to develop power. Beyond vehicles, Aquarius is developing the engine for use as an off-grid micro-generator.

First created in 2014, Aquarius’ efficient single-piston linear engine has a single central cylinder in which the piston moves between two engine heads. In previous iterations, Aquarius used more conventional fossil fuels to create combustion, but now it’s turning attention to emissions-slashing hydrogen. The company says Austrian engineering firm AVL-Schrick recently completed third-party testing, verifying that a modified version of the engine can operate purely on hydrogen.

“It was always our dream at Aquarius Engines to breathe oxygen into hydrogen technology as the fuel of the future,” explains Aquarius chairman Gal Fridman. “From initial tests, it appears that our hydrogen engine, that doesn’t require costly hydrogen fuel-cells, could be the affordable, green and sustainable answer to the challenges faced by global transport and remote energy production.”