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Category: transportation – Page 2

In Active Solids, Connectivity Is as Important as Activity

A robotic metamaterial shows that the odd mechanics of active solids depend on how the active constituents connect across the system.

Active materials, composed of microscopic constituents that continuously inject motional energy into the system, can exhibit odd mechanical responses, such as stretching vertically when sheared horizontally. Such properties can be used to make materials that can spontaneously crawl or roll over a difficult terrain [1]. One might naively think that these desirable odd responses could be increased by making the components more active. Jack Binysh of the University of Amsterdam and his colleagues now find that this doesn’t always work [2]. The researchers show that in active solids a collective response only emerges when system-spanning connective networks are formed among the individual constituents of the system. Without such networks, the effects of microscopic activity remain confined locally and the macroscopic response disappears.

An active solid is, fundamentally, an elastic lattice made up of self-driving constituents. Examples include robotic lattices composed of motorized units [1, 2], magnetic colloidal crystals [3], and chiral living embryos [4]. The active solids that Binysh and his colleagues examined are examples of nonreciprocal active solids, meaning that the interactions between elements are directional. Interactions may become directional when individual constituents process information about their neighbors. Such nonreciprocal interactions arise in a wide range of settings. In robotic metamaterials, local control loops impose directional responses on adjacent mechanical units [1]. And in living chiral collectives, hydrodynamic flows allow rotating embryos to exchange momentum with the surrounding media [4].

Protein clusters reshape cell movement and may help cells build amino acids faster

Cells can be thought of as cities, with factories, a transport system, and lots of building activity. An international team led by scientists at the University of Groningen studied cells growing under different conditions and measured the speed of molecule transport. They found that some conditions led to changes in the mobility inside the cells, caused by the clustering of proteins that produce the building materials for growth. It could be that clustering enables the proteins to produce those building blocks more efficiently. The research is published in the journal Molecular Cell.

The research started with a seemingly simple question. How much movement is there within a cell? “We provided bacteria with different nutrients and this resulted in different growth rates,” explains Matthias Heinemann, Professor of Molecular Systems Biology. Movement was measured by inserting tiny (40 nanometers) fluorescent particles in the cells that could be tracked under the microscope. “To our surprise, we found that particle movement under different conditions could vary by a factor of three.”

The scientific literature could not explain this observation. By analyzing the cell content, the scientists found a correlation between movement of the fluorescent particles and the number of proteins that are involved in the production of amino acids. “More of these proteins meant less movement inside the cell,” says Heinemann. “This led us to the question of why this happens. Our hypothesis was that these proteins form clusters that act as obstacles to movement inside the cells.”

Phase-changing VO₂ turns methane into propane and hydrogen more efficiently

Converting methane, the primary component of natural gas, into higher alkanes and hydrogen, could be highly advantageous. Alkanes, such as propane and butane, are easier to transport than methane and are used in a wider range of industries. Hydrogen, on the other hand, is a promising clean fuel used to power electrochemical devices that can generate continuous power, known as fuel cells.

Over the past decades, some energy engineers have been exploring the possibility of converting methane into hydrogen or complex hydrocarbons using photocatalysts. These are materials activated by sunlight or other types of light and that can drive chemical reactions.

Researchers at Université de Lille—CNRS, Sorbonne Université and other institutes in France recently introduced a new strategy for the photocatalytic conversion of methane into propane, which is widely used for heating, cooking, and transportation.

New hydrogen fuel cell design could unlock key clean energy technology

UNSW researchers have redesigned hydrogen fuel cells to solve a critical flaw, bringing clean energy for aviation, heavy transport and beyond closer to reality. Hydrogen fuel cells, using locally produced green hydrogen as the only fuel, have long been viewed as the ultimate clean energy source, but their commercialization has been difficult.

A multidisciplinary team from UNSW, led by Dr. Quentin Meyer and Professor Chuan Zhao from the School of Chemistry, has managed to make hydrogen fuel cells much more efficient, paving the way for their commercialization.

“Hydrogen fuel cells generate clean electricity with water as the only byproduct,” says Dr. Quentin Meyer, a Senior Research Fellow in Prof. Zhao’s team, and first author of the research published in the journal Applied Catalysis B: Environment and Energy.

‘Voorhees law’ explains why the slower car often catches up

Many drivers will know the feeling: you pull ahead of the slower car you’ve been stuck behind and cruise the open road ahead at your own, faster speed. By the time you reach the next stop light, you’re sure that you’ve left the slower car far behind you—but to your surprise, you see that same car cruise up right behind you in the mirror. Horror buffs might even recall scenes from “Friday the 13th,” where masked villain Jason Voorhees always catches up to his sprinting victims—despite himself walking at a leisurely pace.

In a new study published in Royal Society Open Science, Conor Boland at Dublin City University shows that this unsettlingly common phenomenon can be explained with simple mathematics. His model reveals precisely when and why a slower vehicle catches up after being overtaken, offering fresh insights into how individual vehicles interact with traffic signals.

Breaking fuel cell barriers: New platinum catalyst brings high-efficiency hydrogen vehicles closer to commercialization

A research team has developed a next-generation platinum-based catalyst that improves both activity and durability in hydrogen fuel cells. The study is published in Advanced Materials. The team was led by Professor Sang Uck Lee of the School of Chemical Engineering at Sungkyunkwan University, with Ph.D. candidate Jun Ho Seok as a co-first author and Dr. Sung Chan Cho, in collaboration with Professor Kwangyeol Lee’s team at Korea University and Dr. Sung Jong Yoo’s team at the Korea Institute of Science and Technology (KIST).

Hydrogen fuel cells generate electricity through the electrochemical reaction of hydrogen and oxygen and are considered a promising clean energy technology. However, their broader commercialization has been hindered by the sluggish oxygen reduction reaction (ORR) at the cathode and by catalyst degradation during long-term operation.

Conventional platinum-based intermetallic catalysts are known for their structural stability, but their atomic composition and arrangement are difficult to tune precisely. This has limited efforts to optimize their electronic structure and has made it challenging to achieve both high catalytic activity and long-term durability under demanding operating conditions, such as those required for hydrogen-powered vehicles.

Stretching metals can tune catalysis: A new method predicts energy shifts

Heterogeneous catalysis—in which catalysts and reactants are of different phases, e.g., solid and gas—is important to many industrial processes and often involves solid metal as the catalyst. Ammonia synthesis, catalytic converters for automobile exhaust, methanol synthesis, carbon dioxide reduction, and hydrogen production are examples of such metal-catalyzed heterogeneous catalysis.

The electronic structure of metal surfaces governs the adsorption of reactants and intermediates, and thus the catalytic activity. For this reason, strain engineering —which tunes the electronic structure of a metal catalyst by stretching or compressing its crystal lattice—has emerged as an important strategy for enhancing catalytic performance. Unfortunately, scientists have not been able to quantify how metal strain influences adsorption energies and reaction barriers across different metal catalysts, thereby limiting the rational design of catalysts with desired properties.

To address this challenge, a research team from the Lanzhou Institute of Chemical Physics (LICP) of the Chinese Academy of Sciences has developed a method to predict how strain modifies adsorption energies and reaction barriers across diverse metal systems. The study is published in the journal Cell Reports Physical Science.

Aurora begins final assembly of revolutionary X-65 aircraft

Aurora Flight Sciences said the fuselage of its X-65 experimental aircraft has arrived for final systems integration.

The Boeing subsidiary said teams in Virginia are now installing the aircraft’s electrical, propulsion, and active flow control systems, while wing and tail production continues at its facility in West Virginia. The update marks the program’s transition from major structural assembly into the final integration phase ahead of flight testing.

“The X-65 fuselage has arrived! Our teams are now integrating electrical, propulsion, and AFC systems into the aircraft fuselage in Virginia, while wing and tail manufacturing is advancing at our facility in West Virginia,” the company said.

Can planes evacuate in 90 seconds? New simulations show the safest cabin layout

In case of an emergency, the Federal Aviation Administration requires aircraft to be able to evacuate within 90 seconds. However, as the median age of the global population increases, the growing number of elderly airline passengers poses new challenges during emergency situations.

In AIP Advances, an international collaboration of researchers simulated 27 different evacuation scenarios in the case of a dual-engine fire in an Airbus A320, one of the most common narrow-body aircraft in the world. They compared three different cabin layouts with three different ratios of passengers over the age of 60 and three different distributions of those passengers.

“While a dual-engine fire scenario is statistically rare, it falls under the broader category of dual-engine failures and critical emergencies in aviation. History has shown that dual-engine failures and emergencies, such as the famous ‘Miracle on the Hudson’ involving Captain Sullenberger, can happen and lead to severe consequences,” said author Chenyang (Luca) Zhang.

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