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A Lab Version of Planetary Atmospheres

Researchers recreate key features of atmospheric turbulence in a meter-sized rotating cylinder.

Atmospheric turbulence encompasses a wide range of flow patterns, from 10-m-wide eddies to 1000-km-long wind streams. Geoscientists want to understand how energy and rotational motion transfer (or “cascade”) from one length scale to another, but atmospheric observations have not provided clear answers. A new model of the atmosphere consisting of fluid in a rotating, meter-wide cylinder is able to reproduce key features of observed turbulence [1]. Using video tracking, researchers mapped out the flow velocity in this system, uncovering the dominant role of a “vorticity” transfer that distributes rotational motion from large vortices into smaller ones. This form of cascade may explain the energy distribution in large-scale turbulence on Earth as well as on other planets.

Turbulence can be characterized by a kinetic energy spectrum, which indicates the amount of energy found in fluctuations at each length scale. The typical turbulence spectrum has a mathematical form called a power law, in which the energy density steadily decreases from large to small scales. Fluid dynamics models of Earth’s atmosphere have predicted that the power law should be relatively flat at large scales (with an exponent of −5÷3) and steeper at small scales (with an exponent of −3). However, these predictions aren’t supported by observations. “The basic shape of the spectrum is all wrong,” says Peter Read from the University of Oxford in the UK. Data taken by airplanes have revealed a spectrum that starts out steep at large scales (greater than 500 km) and becomes flatter at small scales.

First quantum oscillations observed in gallium nitride holes

Gallium nitride, a semiconductor that can operate at high voltages, temperatures, and frequencies, has enabled technologies from LED lighting to high-power electronics. Now Cornell researchers have observed a quantum property of the material for the first time, an advance that could expand its technological reach.

Much of gallium nitride’s value as a semiconductor lies in how quickly negatively charged electrons move through the material. But the material could become even more useful if scientists better understood its positively charged “holes,” which behave like mobile pockets of missing electrons but have been difficult to study.

Understanding how to control the flow of the holes—as engineers have achieved in silicon semiconductors—would allow gallium nitride to reach its full potential.

New controls can stretch, blur and even reverse quantum time flow

In new research published in Physical Review X, scientists have designed quantum control protocols that generate processes more consistent with time flowing backward than forward. The protocols—techniques to control quantum systems—modify a quantum system’s “arrow of time,” the concept of time as moving in one forward direction. The work opens up possibilities for energy extraction from quantum systems and for quantum state preparation.

A quantum system, such as a collection of qubits, is governed by the laws of quantum mechanics. The team’s control protocols can prevent the emergence of the arrow of time in a quantum system or even invert its direction—that is, cause quantum time to appear to flow in reverse.

As an application of their research, the team leveraged their control protocols to design a measurement engine that extracts energy from quantum measurements performed on the system.

Atomic disorder strategy could help high-capacity batteries last longer

Researchers at UNIST, in collaboration with the Pohang Accelerator Laboratory (PAL) and KAIST, have introduced a novel approach to stabilizing high-capacity battery materials. By intentionally inducing atomic-level disorder within lithium-rich layered oxide (LRLO) cathodes, the team has effectively minimized structural degradation and energy losses, paving the way for next-generation batteries with higher energy density and longer lifespan.

The findings of this research have been published online in ACS Energy Letters.

Lithium-rich layered oxides (LRLO) are among the most promising cathode materials for future energy storage solutions due to their exceptional capacity, which involves not only metal ions but also oxygen participating in electrochemical reactions. However, their practical application has been hindered by structural instability during repeated charge and discharge cycles, leading to capacity fade and voltage degradation.

Next-generation memory material has the surprising property of shrinking when heated

Most materials we use in everyday life expand slightly when heated and return to their original size when cooled. In addition to such thermal properties, materials can also have electrical properties or magnetic properties, and traditionally we have used these characteristics separately. However, some materials allow multiple properties to coexist within a single substance.

Research on such materials is expected to contribute to the development of next-generation memory devices that can store and retain information while consuming far less energy.

How multiferroics could transform memory A representative example is a class of materials known as multiferroics, which combine the properties of a capacitor (the ability to store electric charge) and a magnet. Among them, bismuth ferrite (BiFeO₃) is one of the most intensively studied materials in the field. When an external voltage is applied, the direction of its stored electric polarization can be switched, and this change can also influence its magnetic properties.

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Hosted by Matt O’Dowd
Written by Fernando Franco Félix & Matt O’Dowd
Post Production by Leonardo Scholzer, Yago Ballarini, Pedro Osinski, Adriano Leal & Stephanie Faria
GFX Visualizations: Ajay Manuel
Directed by Andrew Kornhaber
Assistant Producer: Setare Gholipour
Executive Producers: Eric Brown & Andrew Kornhaber.

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Wearable thermoelectric technology uses thin films to generate electricity from body heat

Seoul National University College of Engineering has announced that a research team led by Prof. Jeonghun Kwak of the Department of Electrical and Computer Engineering, with co-first authors Dr. Juhyung Park and Dr. Sun Hong Kim, has developed a flexible and thin “pseudo-transverse thermoelectric generator” capable of producing electricity from body heat. The research findings appear in Science Advances.

Thermoelectric generators, which convert temperature differences into electricity, are attracting attention as a next-generation energy technology for wearable electronics because they can supply power without batteries. In particular, thin-film thermoelectric generators are lightweight and flexible, allowing them to be comfortably attached to skin or clothing.

However, this thin structure also presents a limitation. Thermoelectric generators require a temperature difference between hot and cold sides to generate electricity. When such a device is attached flat to the skin, body heat passes directly through the thin film and dissipates into the surrounding air—similar to heat passing through a sheet of paper. As a result, little to no temperature difference is formed across the device, making electricity generation difficult.

Redox regulation of the transcription factor HAT1 limits basal defenses and promotes responses to infection in Arabidopsis thaliana

A study in Science Signaling reveals a molecular “brake” in plants that fine-tunes the immune response to infection, casting light on the sophisticated and dynamic pathways that enable plants to balance energy between growth and immune defense.

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The redox status of cysteine residues in a transcription factor balances plant defense gene expression.

Physicists break longstanding high-temperature superconductivity record at ambient pressure

Researchers from the Texas Center for Superconductivity (TcSUH) and the department of physics at the University of Houston have broken the temperature record for superconductivity at ambient pressure—a breakthrough that could eventually lead to more efficient ways to generate, transmit, and store energy.

The UH team achieved a transition temperature (Tc) of 151 Kelvin (about minus 122 degrees Celsius) under ambient pressure—the highest ever recorded for all the reported superconductors at ambient pressure since the discovery of superconductivity in 1911. The transition temperature is the point below which a material becomes superconducting, meaning electricity can flow through it without resistance.

Raising this temperature has been a major goal in superconductivity research for decades. The closer scientists can push the Tc toward room temperature, the more practical and affordable superconducting technologies could become.

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