applied physics (55)

As The Worm Turns...

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Schematic diagram of the worm-inspired robot. Credit: Jin et al.

Topics: Applied Physics, Biomimetics, Instrumentation, Mechanical Engineering, Robotics

Bio-inspired robots, robotic systems that emulate the appearance, movements, and/or functions of specific biological systems, could help to tackle real-world problems more efficiently and reliably. Over the past two decades, roboticists have introduced a growing number of these robots, some of which draw inspiration from fruit flies, worms, and other small organisms.

Researchers at China University of Petroleum (East China) recently developed a worm-inspired robot with a body structure that is based on the oriental paper-folding art of origami. This robotic system, introduced in Bioinspiration & Biomimetics, is based on actuators that respond to magnetic forces, compressing and bending its body to replicate the movements of worms.

"Soft robotics is a promising field that our research group has been paying a lot of attention to," Jianlin Liu, one of the researchers who developed the robot, told Tech Xplore. "While reviewing the existing research literature in the field, we found that bionic robots, such as worm-inspired robots, were a topic worth exploring. We thus set out to fabricate a worm-like origami robot based on the existing literature. After designing and reviewing several different structures, we chose to focus on a specific knitting pattern for our robot."

A worm-inspired robot based on an origami structure and magnetic actuators, Ingrid Fadelli, Tech Xplore

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Solar...

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The LRESE parabolic dish: the solar reactor converts solar energy to hydrogen with an efficiency of more than 20%, producing around 0.5 kg of "green" hydrogen per day. (Courtesy: LRESE EPFL)

Topics: Applied Physics, Energy, Environment, Research, Solar Power

A new solar-radiation-concentrating device produces “green” hydrogen at a rate of more than 2 kilowatts while maintaining efficiencies above 20%. The pilot-scale device, which is already operational under real sunlight conditions, also produces usable heat and oxygen, and its developers at the École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland say it could be commercialized in the near future.

The new system sits on a concrete foundation on the EPFL campus and consists of a parabolic dish seven meters in diameter. This dish collects sunlight over a total area of 38.5 m2, concentrates it by a factor of about 1000, and directs it onto a reactor that comprises both photovoltaic and electrolysis components. Energy from the concentrated sunlight generates electron-hole pairs in the photovoltaic material, which the system then separates and transports to the integrated electrolysis system. Here, the energy is used to “split” water pumped through the system at an optimal rate, producing oxygen and hydrogen.

Putting it together at scale

Each of these processes has, of course, been demonstrated before. Indeed, the new EPFL system, which is described in Nature Energy, builds on previous research from 2019, when the EPFL team demonstrated the same concept at a laboratory scale using a high-flux solar simulator. However, the new reactor’s solar-to-hydrogen efficiency and hydrogen production rate of around 0.5 kg per day is unprecedented in large-scale devices. The reactor also produces usable heat at a temperature of 70°C.

The versatility of the new system forms a big part of its commercial appeal, says Sophia Haussener, who leads the EPFL’s Laboratory of Renewable Energy Science and Engineering (LRESE). “This co-generation system could be used in industrial applications such as metal processing and fertilizer manufacturing,” Haussener tells Physics World. “It could also be used to produce oxygen for use in hospitals and hydrogen for fuels cells in electric vehicles, as well as heat in residential settings for heating water. The hydrogen produced could also be converted to electricity after being stored between days or even inter-seasonally.”

Concentrated solar reactor generates unprecedented amounts of hydrogen, Isabelle Dumé, Physics World.

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Balsa Chips...

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Modified wood modulates electrical current: researchers at Linköping University and colleagues from the KTH Royal Institute of Technology have developed the world’s first electrical transistor made of wood. (Courtesy: Thor Balkhed)

Topics: Applied Physics, Biomimetics, Electrical Engineering, Materials Science, Research

Researchers in Sweden have built a transistor out of a plank of wood by incorporating electrically conducting polymers throughout the material to retain space for an ionically conductive electrolyte. The new technique makes it possible, in principle, to use wood as a template for numerous electronic components, though the Linköping University team acknowledges that wood-based devices cannot compete with traditional circuitry on speed or size.

Led by Isak Engquist of Linköping’s Laboratory for Organic Electronics, the researchers began by removing the lignin from a plank of balsa wood (chosen because it is grainless and evenly structured) using a NaClO2 chemical and heat treatment. Since lignin typically constitutes 25% of wood, removing it creates considerable scope for incorporating new materials into the structure that remains.

The researchers then placed the delignified wood in a water-based dispersion of an electrically conducting polymer called poly(3,4-ethylene-dioxythiophene)–polystyrene sulfonate, or PEDOT: PSS. Once this polymer diffuses into the wood, the previously insulating material becomes a conductor with an electrical conductivity of up to 69 Siemens per meter – a phenomenon the researchers attribute to the formation of PEDOT: PSS microstructures inside the 3D wooden “scaffold.”

Next, Engquist and colleagues constructed a transistor using one piece of this treated balsa wood as a channel and additional pieces on either side to form a double transistor gate. They also soaked the interface between the gates and channels in an ion-conducting gel. In this arrangement, known as an organic electrochemical transistor (OECT), applying a voltage to the gate(s) triggers an electrochemical reaction in the channel that makes the PEDOT molecules non-conducting and therefore switches the transistor off.

A transistor made from wood, Isabelle Dumé, Physics World

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Fractals are a never-ending pattern that you can zoom in on, and the image doesn’t change. Fractals can occur in two dimensions, like frost on a window, or in three dimensions, like tree limbs. A recent discovery from Purdue University researchers has established that superconducting images, seen above in red and blue, are actually fractals that fill a three-dimensional space and are disorder driven rather than driven by quantum fluctuations as expected. Frost and tree images by Adobe. Superconducting image (center) from "Critical nematic correlations throughout the superconducting doping range in Bi2-xPbzSr2-yLayCuO6+x" in Nature Communications. Credit: Nature Communications (2023). DOI: 10.1038/s41467-023-38249-3

Topics: Applied Physics, Civilization, Computer Modeling, Condensed Matter Physics, Materials Science, Solid-State Physics, Superconductors

Meeting the world's energy demands is reaching a critical point. Powering the technological age has caused issues globally. It is increasingly important to create superconductors that can operate at ambient pressure and temperature. This would go a long way toward solving the energy crisis.

Advancements with superconductivity hinge on advances in quantum materials. When electrons inside quantum materials undergo a phase transition, the electrons can form intricate patterns, such as fractals. A fractal is a never-ending pattern. When zooming in on a fractal, the image looks the same. Commonly seen fractals can be a tree or frost on a windowpane in winter. Fractals can form in two dimensions, like the frost on a window, or in three-dimensional space, like the limbs of a tree.

Dr. Erica Carlson, a 150th Anniversary Professor of Physics and Astronomy at Purdue University, led a team that developed theoretical techniques for characterizing the fractal shapes that these electrons make in order to uncover the underlying physics driving the patterns.

Carlson, a theoretical physicist, has evaluated high-resolution images of the locations of electrons in the superconductor Bi2-xPbzSr2-yLayCuO6+x (BSCO) and determined that these images are indeed fractal and discovered that they extend into the full three-dimensional space occupied by the material, like a tree filling space.

What was once thought of as random dispersions within the fractal images are purposeful and, shockingly, not due to an underlying quantum phase transition as expected but due to a disorder-driven phase transition.

Carlson led a collaborative team of researchers across multiple institutions and published their findings, titled "Critical nematic correlations throughout the superconducting doping range in Bi2-xPbzSr2-yLayCuO6+x," in Nature Communications.

The team includes Purdue scientists and partner institutions. From Purdue, the team includes Carlson, Dr. Forrest Simmons, a recent Ph.D. student, and former Ph.D. students Dr. Shuo Liu and Dr. Benjamin Phillabaum. The Purdue team completed their work within the Purdue Quantum Science and Engineering Institute (PQSEI). The team from partner institutions includes Dr. Jennifer Hoffman, Dr. Can-Li Song, Dr. Elizabeth Main of Harvard University, Dr. Karin Dahmen of the University of Illinois at Urbana-Champaign, and Dr. Eric Hudson of Pennsylvania State University.

Researchers discover superconductive images are actually 3D and disorder-driven fractals, Cheryl Pierce, Purdue University, Phys.org.

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Electrical Wound Care...

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New research from Chalmers University of Technology, Sweden, and the University of Freiburg, Germany, shows that wounds on cultured skin cells heal three times faster when stimulated with electric current. The project was recently granted more funding so the research can get one step closer to the market and the benefit of patients. Credit: Science Brush, Hassan A. Tahin

Topics: Applied Physics, Biotechnology, Medicine

Chronic wounds are a major health problem for diabetic patients and the elderly—in extreme cases, they can even lead to amputation. Using electric stimulation, researchers in a project at Chalmers University of Technology, Sweden, and the University of Freiburg, Germany, have developed a method that speeds up healing, making wounds heal three times faster.

There is an old Swedish saying that one should never neglect a small wound or a friend in need. For most people, a small wound does not lead to any serious complications, but many common diagnoses make wound healing far more difficult. People with diabetes, spinal injuries, or poor blood circulation have impaired wound-healing ability. This means a greater risk of infection and chronic wounds—which can lead to serious consequences like amputation in the long run.

Now a group of researchers at Chalmers and the University of Freiburg have developed a method using electric stimulation to speed up the healing process. The study, "Bioelectronic microfluidic wound healing: a platform for investigating direct current stimulation of injured cell collectives," was published in the Lab on a Chip journal.

"Chronic wounds are a huge societal problem that we don't hear much about. Our discovery of a method that may heal wounds up to three times faster can be a game changer for diabetic and elderly people, among others, who often suffer greatly from wounds that won't heal," says Maria Asplund, Associate Professor of Bioelectronics at the Chalmers University of Technology and head of research on the project.

How electricity can heal wounds three times faster, The Chalmers University of Technology

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Strange Metals II...

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Credit: CC0 Public Domain

Topics: Applied Physics, Chemistry, Materials Science, Metamaterials, Quantum Mechanics

The behavior of so-called "strange metals" has long puzzled scientists—but a group of researchers at the University of Toronto may be one step closer to understanding these materials.

Electrons are discrete, subatomic particles that flow through wires like molecules of water flowing through a pipe. The flow is known as electricity, and it is harnessed to power and control everything from lightbulbs to the Large Hadron Collider.

In quantum matter, by contrast, electrons don't behave as they do in normal materials. They are much stronger, and the four fundamental properties of electrons—charge, spin, orbit, and lattice—become intertwined, resulting in complex states of matter.

"In quantum matter, electrons shed their particle-like character and exhibit strange collective behavior," says condensed matter physicist Arun Paramekanti, a professor in the U of T's Department of Physics in the Faculty of Arts & Science. "These materials are known as non-Fermi liquids, in which the simple rules break down."

Now, three researchers from the university's Department of Physics and Centre for Quantum Information & Quantum Control (CQIQC) have developed a theoretical model describing the interactions between subatomic particles in non-Fermi liquids. The framework expands on existing models and will help researchers understand the behavior of these "strange metals."

Their research was published in the journal Proceedings of the National Academy of Sciences (PNAS). The lead author is physics Ph.D. student Andrew Hardy, with co-authors Paramekanti and post-doctoral researcher Arijit Haldar.

"We know that the flow of a complex fluid like blood through arteries is much harder to understand than water through pipes," says Paramekanti. "Similarly, the flow of electrons in non-Fermi liquids is much harder to study than that in simple metals."

Hardy adds, "What we've done is construct a model, a tool, to study non-Fermi liquid behavior. And specifically, to deal with what happens when there is symmetry breaking, when there is a phase transition into a new type of system."

"Symmetry breaking" is the term used to describe a fundamental process found in all of nature. Symmetry breaks when a system—whether a droplet of water or the entire universe—loses its symmetry and homogeneity and becomes more complex.

Researchers develop new insight into the enigmatic realm of 'strange metals', Chris Sasaki, University of Toronto, Phys.org

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Green Homing...

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Divine light The Dean of Gloucester Cathedral, Stephen Lake, blesses the cathedral’s solar panels after the solar-energy firm MyPower installed them in November 2016. The array of PV panels generates just over 25% of the building’s electricity. (Courtesy: MyPower)

Topics: Alternate Energy, Applied Physics, Battery, Chemistry, Economics, Solar Power

With energy bills on the rise, plenty of people are interested in ditching the fossil fuels currently used to heat most UK homes. The question is how to make it happen, as Margaret Harris explains.

Deep beneath the flagstones of the medieval Bath Abbey church, a modern marvel with an ancient twist is silently making its presence felt. Completed in March 2021, the abbey’s heating system combines underfloor pipes with heat exchangers located seven meters below the surface. There, a drain built nearly 2000 years ago carries 1.1 million liters of 40 °C water every day from a natural hot spring into a complex of ancient Roman baths.

By tapping into this flow of warm water, the system provides enough energy to heat not only the abbey but also an adjacent row of Georgian cottages used for offices. No wonder the abbey’s rector praised it as “a sustainable solution for heating our beautiful historic church.”

But that wasn’t all. Once efforts to decarbonize the abbey’s heating were underway, officials in the £19.4m Bath Abbey Footprint project turned their attention to the building’s electricity. Like most churches, the abbey runs from east to west, giving its roof an extensive south-facing aspect. At the UK’s northerly latitudes, such roofs are bathed in sunlight for much of the day, making them ideal for solar photovoltaic (PV) panels. Gloucester Cathedral – an hour’s drive north of Bath – has already taken advantage of this favorable orientation, becoming – in 2016 – the UK’s first major ancient cathedral to have solar panels installed on its roof.

To find out if a similar set-up might be suitable at Bath Abbey, the Footprint project worked with Ph.D. students in the University of Bath-led Centre for Doctoral Training (CDT) in New and Sustainable Photovoltaics. In a feasibility study published in Energy Science & Engineering (2022 10 892), the students calculated that a well-designed array of PV panels could supply 35.7% of the abbey’s electricity, plus 4.6% that could be sold back to the grid on days when a surplus was generated. The array would pay for itself within about 13 years and generate a total profit of £139,000 ± £12,000 over its 25-year lifetime.

Home, green home: scientific solutions for cutting carbon and (maybe) saving money, Margaret Harris, Physics World

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Caveat Super...

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A diamond anvil is used to put superconducting materials under high pressure. Credit: J. Adam Fenster/University of Rochester

Topics: Applied Physics, Condensed Matter Physics, Materials Science, Superconductors

Will a possible breakthrough for room-temperature superconducting materials hold up to scrutiny?

This week researchers claimed to have discovered a superconducting material that can shuttle electricity with no loss of energy under near-real-world conditions. But drama and controversy behind the scenes have many worried that the breakthrough may not hold up to scientific scrutiny.

“If you were to find a room-temperature, room-pressure superconductor, you’d have a completely new host of technologies that would occur—that we haven’t even begun to dream about,” says Eva Zurek, a computational chemist at the University at Buffalo, who was not involved in the new study. “This could be a real game changer if it turns out to be correct.”

Scientists have been studying superconductors for more than a century. By carrying electricity without shedding energy in the form of heat, these materials could make it possible to create incredibly efficient power lines and electronics that never overheat. Superconductors also repel magnetic fields. This property lets researchers levitate magnets over a superconducting material as a fun experiment—and it could also lead to more efficient high-speed maglev trains. Additionally, these materials could produce super strong magnets for use in wind turbines, portable magnetic resonance imaging machines, or even nuclear fusion power plants.

The only superconducting materials previously discovered require extreme conditions to function, which makes them impractical for many real-world applications. The first known superconductors had to be cooled with liquid helium to temperatures only a few degrees above absolute zero. In the 1980s, researchers found superconductivity in a category of materials called cuprates, which work at higher temperatures yet still require cooling with liquid nitrogen. Since 2015 scientists have measured room-temperature superconductive behavior in hydrogen-rich materials called hydrides. but they have to be pressed in a sophisticated viselike instrument called a diamond anvil cell until they reach a pressure of about a quarter to half of that found near the center of Earth.

The new material, called nitrogen-doped lutetium hydride, is a blend of hydrogen, the rare-earth metal lutetium, and nitrogen. Although this material also relies on a diamond anvil cell, the study found that it begins exhibiting superconductive behavior at a pressure of about 10,000 atmospheres—roughly 100 times lower than the pressures that other hydrides require. The new material is “much closer to ambient pressure than previous materials,” says David Ceperley, a condensed matter physicist at the University of Illinois at Urbana-Champaign, who was not involved in the new study. He also notes that the material remains stable when stored at a room pressure of one atmosphere. “Previous stuff was only stable at a million atmospheres, so you couldn’t really take it out of the diamond anvil” cell, he says. “The fact that it’s stable at one atmosphere of pressure also means that it’d be easier to manufacture.”

Controversy Surrounds Blockbuster Superconductivity Claim, Sophie Bushwick, Scientific American

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When Water Outpaces Silicon…

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On target: Water is fanned out through a specially developed nozzle, and then a laser pulse is passed through it to create a switch. (Courtesy: Adrian Buchmann)

Topics: Applied Physics, Lasers, Materials Science, Photonics, Semiconductor Technology

A laser-controlled water-based switch that operates twice as fast as existing semiconductor switches has been developed by a trio of physicists in Germany. Adrian Buchmann, Claudius Hoberg, and Fabio Novelli at Ruhr University Bochum used an ultrashort laser pulse to create a temporary metal-like state in a jet of liquid water. This altered the transmission of terahertz pulses over timescales of just tens of femtoseconds.

With the latest semiconductor-based switches approaching fundamental upper limits on how fast they can operate, researchers are searching for faster ways of switching signals. One unexpected place to look for inspiration is the curious behavior of water under extreme conditions – like those deep within ice-giant planets or created by powerful lasers.

Molecular dynamics simulations suggest water enters a metallic state at pressures of 300 GPa and temperatures of 7000 K. While such conditions do not occur on Earth, it is possible that this state contributes to the magnetic fields of Uranus and Neptune. To study this effect closer to home, recent experiments have used powerful, ultrashort laser pulses to trigger photo-ionization in water-based solutions – creating fleeting, metal-like states.

Water-based switch outpaces semiconductor devices, described in APL Photonics.

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Chip Act and Wave Surfing...

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Massive subsidies to regain the edge of the US semiconductor industry will not likely succeed unless progress is made in winning the global race of idea flow and monetization.

Topics: Applied Physics, Chemistry, Computer Science, Electrical Engineering, Semiconductor Technology

Intelligent use of subsidies for winning the global idea race is a must for gaining and regaining semiconductor edge.

The US semiconductor industry started with the invention of Bell Labs. Subsequently, it attained supremacy in semiconductor production due to the success of making computers better and cheaper. Notably, the rise of the PC wave made Intel and Silicon Valley seemingly unsinkable technology superpowers. But during the first two decades of the 21st century, America has lost it. The USA now relies on Asia to import the most advanced chips. Its iconic Intel is now a couple of technology generation behind Asia’s TSMC and Samsung.

Furthermore, China’s aggressive move has added momentum to America’s despair, triggering a chip war. But why has America lost the edge? Why does it rely on TSMC and Samsung to supply the most advanced chips to power iPhones, Data centers, and Weapons? Is it due to Asian Governments’ subsidies? Or is it due to America’s failure to understand dynamics, make prudent decisions and manage technology and innovation?

Invention and rise and fall of US semiconductor supremacy

In 1947, Bell Labs of the USA invented a semiconductor device—the Transistor. Although American companies developed prototypes of Transistor radios and other consumer electronic products, they did not immediately pursue them. But American firms were very fast in using the Transistor to reinvent computers—by changing the vacuum tube technology core. Due to weight advantage, US Airforce and NASA found transistors suitable for onboard computers. Besides, the invention of integrated circuits by Fairchild and Texas instruments accelerated the weight and size reduction of digital logic circuits. Consequentially, the use of semiconductors in building onboard computers kept exponentially growing. Hence, by the end of the 1960s, the US had become a powerhouse in logic circuit semiconductors. But America remained 2nd to Japan in global production, as Japanese companies were winning the race of consumer electronics by using transistors.

US Semiconductor–from invention, supremacy to despair, Rokon Zaman, The-Waves.org

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CEM and SEI...

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Panel A shows how the native SEI on Li metal is passivating to nitrogen, which means that no reactivity with Li metal is possible. Panel B shows that a proton donor like Ethanol will disrupt the SEI passivation and enable Li metal to react with nitrogen species. Panel C describes 3 potential mechanisms through which the proton donor can disrupt the SEI passivation. Credit: Steinberg et al.

Topics: Applied Physics, Battery, Chemistry, Climate Change, Environment

Ammonia (NH3), the chemical compound made of nitrogen and hydrogen, currently has many valuable uses, for instance, serving as a crop fertilizer, purifying agent, and refrigerant gas. In recent years, scientists have been exploring its potential as an energy carrier to reduce global carbon emissions and help tackle global warming.

Ammonia is produced via the Haber-Bosch process, a carbon-producing industrial chemical reaction that converts nitrogen and hydrogen into NH3. As this process is known to contribute heavily to global carbon emissions, electrifying ammonia synthesis would benefit our planet.

One of the most promising strategies for electrically synthesizing ammonia at ambient conditions is using lithium metal. However, some aspects of these processes, including the properties and role of lithium's passivation layer, known as the solid electrolyte interphase (SEI), remain poorly understood.

Researchers at the Massachusetts Institute of Technology (MIT), the University of California- Los Angeles (UCLA), and the California Institute of Technology have recently conducted a study closely examining the reactivity of lithium and its SEI, as this could enhance lithium-based pathways to electrically synthesize ammonia. Their observations, published in Nature Energy, were collected using a state-of-the-art imaging method known as cryogenic transmission electron microscopy.

Using cryogenic electron microscopy to study the lithium SEI during electrocatalysis, Ingrid Fadelli, Phys.org

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Caveat Emptor...

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National Ignition Facility operators inspect a final optics assembly during a routine maintenance period in August. Photo credit: Lawrence Livermore National Laboratory

Topics: Alternate Energy, Applied Physics, Climate Change, Energy, Global Warming, Lasers, Nuclear Fusion

After the heady, breathtaking coverage of pop science journalism, I dove into the grim world inhabited by the Bulletin of the Atomic Scientists on their take on the first-ever fusion reaction. I can say that I wasn’t surprised. With all this publicity, it will probably get the Nobel Prize nomination (my guess). Cool Trekkie trivia: the National Ignition Facility was the backdrop for the Enterprise's warp core for Into Darkness.

*****

This week’s headlines have been full of reports about a “major breakthrough” in nuclear fusion technology that, many of those reports misleadingly suggested, augurs a future of abundant clean energy produced by fusion nuclear power plants. To be sure, many of those reports lightly hedged their enthusiasm by noting that (as The Guardian put it) “major hurdles” to a fusion-powered world remain.

Indeed, they do.

The fusion achievement that the US Energy Department announced this week is scientifically significant, but the significance does not relate primarily to electricity generation. Researchers at Lawrence Livermore National Laboratory’s National Ignition Facility, or NIF, focused the facility’s 192 lasers on a target containing a small capsule of deuterium–tritium fuel, compressing it and inducing what is known as ignition. In a written press release, the Energy Department described the achievement this way: “On December 5, a team at LLNL’s National Ignition Facility (NIF) conducted the first controlled fusion experiment in history to reach this [fusion ignition] milestone, also known as scientific energy breakeven, meaning it produced more energy from fusion than the laser energy used to drive it. This historic, first-of-its-kind achievement will provide the unprecedented capability to support [the National Nuclear Security Administration’s] Stockpile Stewardship Program and will provide invaluable insights into the prospects of clean fusion energy, which would be a game-changer for efforts to achieve President Biden’s goal of a net-zero carbon economy.”

Because of how the Energy Department presented the breakthrough in a news conference headlined by Energy Secretary Jennifer Granholm, news coverage has largely glossed over its implications for monitoring the country’s nuclear weapons stockpile. Instead, even many serious news outlets focused on the possibility of carbon-free, fusion-powered electricity generation—even though the NIF achievement has, at best, a distant and tangential connection to power production.

To get a balanced view of what the NIF breakthrough does and does not mean, I (John Mecklin) spoke this week with Bob Rosner, a physicist at the University of Chicago and a former director of the Argonne National Laboratory who has been a longtime member of the Bulletin’s Science and Security Board. The interview has been lightly edited and condensed for readability.

See their chat at the link below.

The Energy Department’s fusion breakthrough: It’s not really about generating electricity, John Mecklin, The Bulletin of the Atomic Scientists, Editor-in-Chief

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OPVs...

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V. ALTOUNIAN/SCIENCE

Topics: Alternate Energy, Applied Physics, Chemistry, Materials Science, Solar Power

As ultrathin organic solar cells hit new efficiency records, researchers see green energy potential in surprising places.

In November 2021, while the municipal utility in Marburg, Germany, was performing scheduled maintenance on a hot water storage facility, engineers glued 18 solar panels to the outside of the main 10-meter-high cylindrical tank. It’s not the typical home for solar panels, most of which are flat, rigid silicon and glass rectangles arrayed on rooftops or in solar parks. The Marburg facility’s panels, by contrast, are ultrathin organic films made by Heliatek, a German solar company. In the past few years, Heliatek has mounted its flexible panels on the sides of office towers, the curved roofs of bus stops, and even the cylindrical shaft of an 80-meter-tall windmill. The goal: expanding solar power’s reach beyond flat land. “There is a huge market where classical photovoltaics do not work,” says Jan Birnstock, Heliatek’s chief technical officer.

Organic photovoltaics (OPVs) such as Heliatek’s are more than 10 times lighter than silicon panels and in some cases cost just half as much to produce. Some are even transparent, which has architects envisioning solar panels, not just on rooftops, but incorporated into building facades, windows, and even indoor spaces. “We want to change every building into an electricity-generating building,” Birnstock says.

Heliatek’s panels are among the few OPVs in practical use, and they convert about 9% of the energy in sunlight to electricity. But in recent years, researchers around the globe have come up with new materials and designs that, in small, lab-made prototypes, have reached efficiencies of nearly 20%, approaching silicon and alternative inorganic thin-film solar cells, such as those made from a mix of copper, indium, gallium, and selenium (CIGS). Unlike silicon crystals and CIGS, where researchers are mostly limited to the few chemical options nature gives them, OPVs allow them to tweak bonds, rearrange atoms, and mix in elements from across the periodic table. Those changes represent knobs chemists can adjust to improve their materials’ ability to absorb sunlight, conduct charges, and resist degradation. OPVs still fall short of those measures. But, “There is an enormous white space for exploration,” says Stephen Forrest, an OPV chemist at the University of Michigan, Ann Arbor.

Solar Energy Gets Flexible, Robert F. Service, Science Magazine

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Mirror, Mirror...

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Various views of a 3D-printed object are captured by a single camera using a dome-shaped array of mirrors. Left: The raw image. Right: closeups of some of the individual views. (Image: Sanha Cheong, SLAC National Accelerator Laboratory)

Topics: Applied Physics, Atomic-Scale Microscopy, Materials Science, Optics

(Nanowerk News) When it goes online, the MAGIS-100 experiment at the Fermi National Accelerator Laboratory and its successors will explore the nature of gravitational waves and search for certain kinds of wavelike dark matter. But first, researchers need to figure out something pretty basic: how to get good photographs of the clouds of atoms at the heart of their experiment.

Researchers at the Department of Energy's SLAC National Accelerator Laboratory realized that task would be perhaps the ultimate exercise in ultra-low light photography.

But a SLAC team that included Stanford graduate students Sanha Cheong and Murtaza Safdari, SLAC Professor Ariel Schwartzman, and SLAC scientists Michael Kagan, Sean Gasiorowski, Maxime Vandegar, and Joseph Frish found a simple way to do it: mirrors. By arranging mirrors in a dome-like configuration around an object, they can reflect more light towards the camera and image multiple sides of an object simultaneously.

And, the team reports in the Journal of Instrumentation ("Novel light field imaging device with an enhanced light collection for cold atom clouds"), that there's an additional benefit. Because the camera now gathers views of an object taken from many different angles, the system is an example of “light-field imaging”, which captures not just the intensity of light but also which direction light rays travel. As a result, the mirror system can help researchers build a three-dimensional model of an object, such as an atom cloud.

How do you take a better image of atom clouds? Mirrors - lots of mirrors, SLAC National Accelerator Laboratory

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ARDP...

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The design concept of BWXT Advanced Nuclear Reactor. BWX Technologies

Topics: Applied Physics, Alternate Energy, Climate Change, Nuclear Power

According to the US Energy Information Administration, the US uses a mixture of 60.8% fossil fuel sources to generate 2,504 billion kilowatt hours of energy. Our nuclear expenditure is a paltry 18.9%. The totality of renewable sources (wind, hydropower, solar, biomass, and geothermal) is a little higher: 20.1%. This is the crux of the "Green New Deal."

Though I long for the cleaner, neater version of nuclear power in fusion, it's kind of hard to mimic the pressures and magnetic fields necessary to spark essentially a mini sun on the planet. I think the resistance to nuclear fission is cultural: from the atomic bomb, Oppenheimer quoting the Bhagavad-Gita at the first successful testing, a classic "what have we done" trope. Popular fiction emphasizes doomsday scenarios and radioactive zombies. Honorable mention: Space 1999, which like zombies I doubt could ever happen, but it kept my attention in my youth. There are also genuine concerns about Chernobyl (still in Ukraine), Three-Mile Island, and Fukushima Daichi that come to the public's mind.

The reason the percentages on fossil fuels are so high is that they release extreme amounts of energy to superheat water for turbines to turn magnets superfast in copper coils. That is how most of the electricity we consume is made.

France currently generates 70% of its energy from nuclear power plants, with plans to reduce this to 50% as they mix in renewables. This is proportional to the percentage the US already has in renewables. My only caveat is an obsolescence plan for solar panels (they have to be implanted with caustic impurities to MAKE them conductive, and after twenty years, could end up in a landfill near humans). Battery-operated vehicles are fine, but Lithium has to be mined, it requires a lot of water, typically the indigenous peoples near the mines don't make a profit, and their land and resources are spoiled.

If we truly are going to transition from fossil fuels to "cleaner energy," I think we should realize that power plant designs have improved greatly since the aforementioned disasters.

As an engineer, I always tried to follow this edict from my father: "Experience isn't the best teacher: other people's experiences are the best teacher." In short, learn from others' mistakes, and try to not repeat them. It works in other nontechnical areas of life as well.

I (fingers crossed) assume nuclear power plant design engineers follow something similar to improve on future designs for safety, and as we've been exposed to with the war in Ukraine, global energy security.

I'm proposing an "everything on the table strategy," not Pollyanna. By the way, our "carbon footprint" appears to be a boondoggle by the industries that caused our current malaise.

The U.S. Department of Energy's Advanced Reactor Demonstration Program commonly referred to as ARDP, is designed to help our domestic nuclear industry demonstrate its advanced reactor designs on accelerated timelines. This will ultimately help us build a competitive portfolio of new U.S. reactors that offer significant improvements over today’s technology.

The advanced reactors selected for risk-reduction awards are an excellent representation of the diverse designs currently under development in the United States. They range from advanced light-water-cooled small modular reactors to new designs that use molten salts and high-temperature gases to flexibly operate at even higher temperatures and lower pressures.

All of them have the potential to compete globally once deployed. They will offer consumers more access to a reliable, clean power source that can be depended on in the near future to flexibly generate electricity, drive industrial processes, and even provide potable drinking water to communities in water-scarce locations.

5 Advanced Reactor Designs to Watch in 2030, Alice Caponiti, Deputy Assistant Secretary for Reactor Fleet and Advanced Reactor Deployment, Office of Nuclear Energy

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DUNE Detector...

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The ore pass at the Sanford Underground Research Facility in South Dakota. (Courtesy of Sanford Underground Research Facility, CC BY-NC-ND 4.0.)

Topics: Applied Physics, Modern Physics, Particle Physics, Theoretical Physics

The Deep Underground Neutrino Experiment (DUNE) will be the world’s largest cryogenic particle detector. Its aim is to study the most elusive of particles: neutrinos. Teams from around the world are developing and constructing detector components that they will ship to the Sanford Underground Research Facility, commonly called Sanford Lab, in the Black Hills of South Dakota. There the detector components will be lowered more than a kilometer underground through a narrow shaft to the caverns, where they will be assembled and operated while being sheltered from the cosmic rays that constantly rain down on Earth’s surface.

For at least two decades, the detector will be exposed to the highest-intensity neutrino beam on the planet. The beam will be generated 1300 km away by a megawatt-class proton accelerator and beamline under development at Fermilab in Batavia, Illinois. A smaller detector just downstream of the beamline will measure the neutrinos at the start of their journey, thereby enabling the experiment’s precision and scientific reach.

Building a ship in a bottle for neutrino science, Anne Heavey, FERMILAB, Physics Today

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Perovskite and Maxima...

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The effective mass of the electrons can be derived from the curvature around the maxima of the ARPES measurement data (image, detail). (Courtesy: HZB)

Topics: Alternate Energy, Applied Physics, Battery, Chemistry, Civilization, Climate Change

A longstanding explanation for why perovskite materials make such good solar cells has been cast into doubt thanks to new measurements. Previously, physicists ascribed the favorable optoelectronic properties of lead halide perovskites to the behavior of quasiparticles called polarons within the material’s crystal lattice. Now, however, detailed experiments at Germany’s BESSY II synchrotron revealed that no large polarons are present. The work sheds fresh light on how perovskites can be optimized for real-world applications, including light-emitting diodes, semiconductor lasers, and radiation detectors as well as solar cells.

Lead halide perovskites belong to a family of crystalline materials with an ABXstructure, where A is cesium, methylammonium (MA), or formamidinium (FA); B is lead or tin; and X is chlorine, bromine, or iodine. They are promising candidates for thin-film solar cells and other optoelectronic devices because their tuneable bandgaps enable them to absorb light over a broad range of wavelengths in the solar spectrum. Charge carriers (electrons and holes) also diffuse through them over long distances. These excellent properties give perovskite solar cells a power conversion efficiency of more than 18%, placing them on a par with established solar-cell materials such as silicon, gallium arsenide, and cadmium telluride.

Researchers are still unsure, however, exactly why charge carriers travel so well in perovskites, especially since perovskites contain far more defects than established solar-cell materials. One hypothesis is that polarons – composite particles made up of an electron surrounded by a cloud of ionic phonons, or lattice vibrations – act as screens, preventing charge carriers from interacting with the defects.

Charge-transport mystery deepens in promising solar-cell materials, Isabelle Dumé, Physics World

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Getting Back Mojo...

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Artist's representation of the circular phonons. (Courtesy: Nadja Haji and Peter Baum, University Konstanz)

Topics: Applied Physics, Lasers, Magnetism, Materials Science, Phonons

When a magnetic material is bombarded with short pulses of laser light, it loses its magnetism within femtoseconds (10–15 seconds). The spin, or angular momentum, of the electrons in the material, thus disappears almost instantly. Yet all that angular momentum cannot simply be lost. It must be conserved – somewhere.

Thanks to new ultrafast electron diffraction experiments, researchers at the University of Konstanz in Germany have now found that this “lost” angular momentum is in fact transferred from the electrons to vibrations of the material’s crystal lattice within a few hundred femtoseconds. The finding could have important implications for magnetic data storage and for developments in spintronics, a technology that exploits electron spins to process information without using much power.

In a ferromagnetic material, magnetism occurs because the magnetic moments of the material’s constituent atoms align parallel to each other. The atoms and their electrons then act as elementary electromagnets, and the magnetic fields are produced mainly by the spin of the electrons.

Because an ultrashort laser pulse can rapidly destroy this alignment, some scientists have proposed using such pulses as an off switch for magnetization, thereby enabling ultra-rapid data processing at frequencies approaching those of light. Understanding this ultrafast demagnetization process is thus crucial for developing such applications as well as for better understanding the foundations of magnetism.

Researchers find ‘lost’ angular momentum, Isabelle Dumé, Physics World

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Strain and Flow...

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Topography of the two-dimensional crystal on top of the microscopically small wire indicated by dashed lines. Excitons freely move along the wire-induced dent, but cannot escape it in the perpendicular direction. (Courtesy: Florian Dirnberger)

Topics: Applied Physics, Condensed Matter Physics, Electrical Engineering

Using a technique known as strain engineering, researchers in the US and Germany have constructed an “excitonic wire” – a one-dimensional channel through which electron-hole pairs (excitons) can flow in a two-dimensional semiconductor like water through a pipe. The work could aid the development of a new generation of transistor-like devices.

In the study, a team led by Vinod Menon at the City College of New York (CCNY) Center for Discovery and Innovation and Alexey Chernikov at the Dresden University of Technology and the University of Regensburg in Germany deposited atomically thin 2D crystals of tungsten diselenide (fully encapsulated in another 2D material, hexagonal boride nitride) atop a 100 nm-thin nanowire. The presence of the nanowire created a small, elongated dent in the tungsten diselenide by slightly pulling apart the atoms in the 2D material and so inducing strain in it. According to the study’s lead authors, Florian Dimberger and Jonas Ziegler, this dent behaves for excitons much like a pipe does for water. Once trapped inside, they explain, the excitons are bound to move along the pipe.

Strain guides the flow of excitons in 2D materials, Isabelle Dumé, Physics World

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Martian Windmills...

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Artist's rendition of a future colony on Mars., e71lena via Shutterstock

Topics: Applied Physics, Energy, Mars, Space Exploration

(Inside Science) -- Mars is known for its dust storms, which can cause problems for lander equipment and block out the sun that fuels solar panels. These punishing storms, which can last for weeks, have already caused damage to equipment and even killed NASA’s Opportunity rover. But they could also be dangerous to astronauts on the ground, who would rely on solar power for oxygen, heat, and water cleansing during future missions.

Vera Schorbach, a professor of wind energy at the Hamburg University of Applied Sciences in Germany, was curious to see whether wind turbines could harness the power of these storms, filling in for solar panels on the Red Planet during times of need.

"I asked myself, 'Why don't they have a wind turbine if they have dust storms,'" said Schorbach, the lead author of a study about the potential for wind power on Mars published recently in the journal Acta Astronautica.

Could martian dust storms help astronauts keep the lights on? Joshua Rapp Leam, Astronomy/Inside Science

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