Jan 28, 2023
Can these rocks really power light bulbs?
Posted by Shubham Ghosh Roy in category: energy
Viral videos claim rocks found in Africa can produce an electrical charge. But is this really possible?
Viral videos claim rocks found in Africa can produce an electrical charge. But is this really possible?
A waveguide sculpted in air with lasers transmits light over a distance of nearly 50 meters, which is 60 times farther than previous air-waveguide schemes.
Conventional optical waveguides such as optical fibers and planar waveguides consist of a core surrounded by a cladding with a lower index of refraction. Light is efficiently confined in the core by total internal reflection at the core-cladding boundary. Optical fibers can transport light over 100s of kilometers, but there are applications—such as high-power transmission and atmospheric monitoring—where the use of fibers becomes impractical. Sending light directly through air is not an option, as diffraction effects cause the beam to spread out. A potential solution is to “sculpt” waveguides in the air with laser pulses that produce a low-density cladding around a central core of unperturbed air. Using a new method with donut-shaped beams, Andrew Goffin from the University of Maryland, College Park, and colleagues have created a 45-m-long waveguide in air [1], reaching 60 times farther than the record they previously established for an air waveguide.
The second law of thermodynamics is often considered to be one of only a few physical laws that is absolutely and unquestionably true. The law states that the amount of ‘entropy’—a physical property—of any closed system can never decrease. It adds an ‘arrow of time’ to everyday occurrences, determining which processes are reversible and which are not. It explains why an ice cube placed on a hot stove will always melt, and why compressed gas will always fly out of its container (and never back in) when a valve is opened to the atmosphere.
Only states of equal entropy and energy can be reversibly converted from one to the other. This reversibility condition led to the discovery of thermodynamic processes such as the (idealized) Carnot cycle, which poses an upper limit to how efficiently one can convert heat into work, or the other way around, by cycling a closed system through different temperatures and pressures. Our understanding of this process underpinned the rapid economic development during the Western Industrial Revolution.
The beauty of the second law of thermodynamics is its applicability to any macroscopic system, regardless of the microscopic details. In quantum systems, one of these details may be entanglement: a quantum connection that makes separated components of the system share properties. Intriguingly, quantum entanglement shares many profound similarities with thermodynamics, even though quantum systems are mostly studied in the microscopic regime.
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For high-cobalt cathodes such as lithium cobalt oxide (LCO) conventional pyrometallurgical (see section ‘Pyrometallurgical recovery’) or hydrometallurgical (see section ‘Hydrometallurgical recovery’) recycling processes can recover around 70% of the cathode value11. However, for other cathode chemistries that are not as cobalt-rich, this figure drops notably11. A 2019 648-lb Nissan Leaf battery, for example, costs US$6,500–8,500 new, but the value of the pure metals in the cathode material is less than US$400 and the cost of the equivalent amount of NMC (an alternative cathode material) is in the region of US$4,000. It is important, therefore, to appreciate that cathode material must be directly recycled (or upcycled) to recover sufficient value. As direct recycling avoids lengthy and expensive purification steps, it could be particularly advantageous for lower-value cathodes such as LiMn2O4 and LiFePO4, where manufacturing of the cathode oxides is the major contributor to cathode costs, embedded energy and carbon dioxide footprint95.
Direct recycling also has the advantage that, in principle, all battery components20 can be recovered and re-used after further processing (with the exclusion of separators). Although there is substantial literature regarding the recycling of the cathode component from spent LIBs, research on recycling of the graphitic anode is limited, owing to its lower recovery value. Nevertheless, the successful re-use of mechanically separated graphite anodes from spent batteries has been demonstrated, with similar properties to that of pristine graphite96.
Continue reading “Recycling lithium-ion batteries from electric vehicles” »
A team at the US Department of Energy’s Oak Ridge National Laboratory has developed a utility-scale solar and storage project that can provide power to both AC and DC high-voltage lines, and thus shore up grid stability – here’s how it works.
Most of the US power grid uses alternating current, or AC, which constantly switches the direction of electron flow. But solar and battery storage uses direct current, or DC, that flows in a single direction.
The US power grid includes a smaller number of high-voltage DC lines that are more efficient at delivering bulk power over long distances or to remote regions.
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If these organisms are eating viruses in nature, it could change the way scientists think about global carbon cycling.
The cooking with gas controversy misses the point. The real problem is the transitional fuel strategy.
Congressman Matt Gaetz reacted to a proposed suggestion to regulate gas stoves by saying “you’ll have to pry it from my COLD DEAD HANDS!”
Scientists from UNSW Sydney have demonstrated a novel technique for creating tiny 3D materials that could eventually make fuel cells like hydrogen batteries cheaper and more sustainable.
In the study published in Science Advances (“Synthesis of hierarchical metal nanostructures with high electrocatalytic surface areas”), researchers from the School of Chemistry at UNSW Science show it’s possible to sequentially ‘grow’ interconnected hierarchical structures in 3D at the nanoscale which have unique chemical and physical properties to support energy conversion reactions.
In chemistry, hierarchical structures are configurations of units like molecules within an organisation of other units that themselves may be ordered. Similar phenomena can be seen in the natural world, like in flower petals and tree branches. But where these structures have extraordinary potential is at a level beyond the visibility of the human eye – at the nanoscale.
Two astronauts from the International Space Station (ISS) yesterday performed the first spacewalk of the year, working on the exterior of the station as part of a long-term program to upgrade the ISS power system. The spacewalk took place on Friday, January 20, and lasted over seven hours, though one troublesome strut wasn’t bolted into place as planned.
The two astronauts performing the spacewalk were NASA astronaut Nicole Mann and Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, and this was the first spacewalk for each of them.
The ISS solar arrays which provide power to the station are getting old, so in a long-term project astronauts are installing new arrays called iROSAs at an offset on top of the old arrays — allowing both sets of arrays to provide power. The aim of the spacewalk yesterday was to install two mounting platforms, which would be used to install new solar arrays later this year.