Archive for the ‘energy’ category: Page 2

Apr 18, 2023

Room-temperature superfluidity in a polariton condensate Physics

Posted by in categories: energy, information science, mapping, mathematics, quantum physics, space

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First observed in liquid helium below the lambda point, superfluidity manifests itself in a number of fascinating ways. In the superfluid phase, helium can creep up along the walls of a container, boil without bubbles, or even flow without friction around obstacles. As early as 1938, Fritz London suggested a link between superfluidity and Bose–Einstein condensation (BEC)3. Indeed, superfluidity is now known to be related to the finite amount of energy needed to create collective excitations in the quantum liquid4,5,6,7, and the link proposed by London was further evidenced by the observation of superfluidity in ultracold atomic BECs1,8. A quantitative description is given by the Gross–Pitaevskii (GP) equation9,10 (see Methods) and the perturbation theory for elementary excitations developed by Bogoliubov11. First derived for atomic condensates, this theory has since been successfully applied to a variety of systems, and the mathematical framework of the GP equation naturally leads to important analogies between BEC and nonlinear optics12,13,14. Recently, it has been extended to include condensates out of thermal equilibrium, like those composed of interacting photons or bosonic quasiparticles such as microcavity exciton-polaritons and magnons14,15. In particular, for exciton-polaritons, the observation of many-body effects related to condensation and superfluidity such as the excitation of quantized vortices, the formation of metastable currents and the suppression of scattering from potential barriers2,16,17,18,19,20 have shown the rich phenomenology that exists within non-equilibrium condensates. Polaritons are confined to two dimensions and the reduced dimensionality introduces an additional element of interest for the topological ordering mechanism leading to condensation, as recently evidenced in ref. 21. However, until now, such phenomena have mainly been observed in microcavities embedding quantum wells of III–V or II–VI semiconductors. As a result, experiments must be performed at low temperatures (below ∼ 20 K), beyond which excitons autoionize. This is a consequence of the low binding energy typical of Wannier–Mott excitons. Frenkel excitons, which are characteristic of organic semiconductors, possess large binding energies that readily allow for strong light–matter coupling and the formation of polaritons at room temperature. Remarkably, in spite of weaker interactions as compared to inorganic polaritons22, condensation and the spontaneous formation of vortices have also been observed in organic microcavities23,24,25. However, the small polariton–polariton interaction constants, structural inhomogeneity and short lifetimes in these structures have until now prevented the observation of behaviour directly related to the quantum fluid dynamics (such as superfluidity). In this work, we show that superfluidity can indeed be achieved at room temperature and this is, in part, a result of the much larger polariton densities attainable in organic microcavities, which compensate for their weaker nonlinearities.

Our sample consists of an optical microcavity composed of two dielectric mirrors surrounding a thin film of 2,7-Bis[9,9-di(4-methylphenyl)-fluoren-2-yl]-9,9-di(4-methylphenyl)fluorene (TDAF) organic molecules. Light–matter interaction in this system is so strong that it leads to the formation of hybrid light–matter modes (polaritons), with a Rabi energy 2 ΩR ∼ 0.6 eV. A similar structure has been used previously to demonstrate polariton condensation under high-energy non-resonant excitation24. Upon resonant excitation, it allows for the injection and flow of polaritons with a well-defined density, polarization and group velocity.

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Apr 17, 2023

Vertical farm cuts energy use 75 per cent

Posted by in categories: energy, food, sustainability

A vertical farm built inside a greenhouse in Texas can produce hundreds of thousands of heads of lettuce with significantly less energy than usual.

By James Dinneen

Apr 17, 2023

Jetoptera Just Reinvented Flight With ‘Bladeless Fans on Steroids’

Posted by in categories: energy, transportation

Nearly every air taxi concept involves rapidly spinning propellers or ducted fans placed in strategic positions outside of the main fuselage of the aircraft — moving air fast enough to achieve thrust in the direction of propulsion.

However, a new air taxi concept from a company in Seattle breaks from the norm — reinventing flight with bladeless fans at incredible power levels, according to Jetoptera’s official website.

Apr 16, 2023

Tesla Megapack project breaks ground, Arizona’s largest project yet

Posted by in categories: energy, sustainability

A new Tesla Megapack project has broken ground in Arizona, and when it comes online in 2024, it will be the state’s largest energy storage system.

For utilities, battery energy storage is one of the most helpful new technologies they can employ to reduce fossil fuel dependence and increase the reliability of their associated grid. By holding onto excess power generated during lulls in demand, power companies can more easily address peak demand and, importantly, reduce costs. Now, a new Tesla Megapack energy storage system is set to do just that in Arizona.

The Sierra Estrella energy storage facility, constructed by utility company Salt River Project (SRP) and energy system constructor Plus Power LLC, will be the largest of its kind in Arizona. The massive network of Tesla Megapacks will have a capacity of 1,000MWh, enough energy to power 56,000 homes for four hours. According to previous information released by SRP, the project was set to cost $400 million, but this does not account for the recent Tesla Megapack price cut.

Apr 12, 2023

Exclusive: Tesla is about to launch Powerwall 3

Posted by in categories: energy, sustainability

Tesla is preparing to launch Powerwall 3, the third generation of its home battery pack, according to information obtained by Electrek.

In 2015, when launching its Tesla Energy division, Tesla launched the first generation of the Powerwall, and it quickly became, by far, the most popular home battery pack in the residential market.

Shortly after, Tesla launched Powerwall 2, a new version of the residential battery pack with more energy and power capacity.

Apr 12, 2023

Battery Technology Advancing At A Good Clip

Posted by in categories: chemistry, energy, sustainability, transportation

Electric vehicles feature lithium-ion battery packs today. They are heavy. But in the future lithium-air batteries that are more energy dense, lighter, and smaller could revolutionize EV design.

Lithium-air provides 4x greater energy density, and gets the oxygen needed in the chemical process from the surrounding air.

Apr 9, 2023

Elon Musk unveils $10 trillion ‘Master Plan’ to eliminate fossil fuels

Posted by in categories: Elon Musk, energy, sustainability

Yahoo Finance Live anchors Brad Smith and Jared Blikre break down Tesla’s ‘Master Plan Part 3’.

Video Transcript

BRAD SMITH: Tesla CEO Elon Musk reveals the third part of the EV maker’s master plan is to lead the global effort to convert the world to sustainable energy here. And as part of that, according to Musk, Tesla’s projects will take $10 trillion in investments.

Apr 9, 2023

Physicists Discover that Gravity Can Create Light

Posted by in categories: energy, physics

Researchers have discovered that in the exotic conditions of the early universe, waves of gravity may have shaken space-time so hard that they spontaneously created radiation.

The physical concept of resonance surrounds us in everyday life. When you’re sitting on a swing and want to go higher, you naturally start pumping your legs back and forth. You very quickly find the exact right rhythm to make the swing go higher. If you go off rhythm then the swing stops going higher. This particular kind of phenomenon is known in physics as a parametric resonance.

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Apr 7, 2023

Tokyo Scientists Unveil Solid-State Battery Breakthrough

Posted by in categories: energy, innovation

Researchers at Tokyo University of Science have achieved a two-order improvement in the response speed of solid-state batteries.

Apr 7, 2023

Living electrodes with bacteria and organic electronics

Posted by in categories: chemistry, energy

Researchers at the Laboratory of Organic Electronics, Linköping University, have together with colleagues at the Lawrence Berkeley National Laboratory in Berkeley, California, developed a method that increases the signal strength from microbial electrochemical cells by up to twenty times. The secret is a film with an embedded bacterium: Shewanella oneidensis.

Adding to electrochemical systems is often an environmentally sensitive means to convert chemical energy to electricity. Applications include water purification, bioelectronics, biosensors, and for the harvesting and storage of energy in fuel cells. One problem that miniaturisation of the processes has encountered is that a high requires large electrodes and a large volume of liquid.

Researchers at Linköping University, together with colleagues at the Lawrence Berkeley National Laboratory in Berkeley, California, USA, have now developed a method in which they embed the electroactive Shewanella oneidensis into PEDOT: PSS, an electrically conducting polymer, on a substrate of carbon felt.

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