Understanding a cerium quirk could help advance grid-scale energy storage

When the cerium atom is short three electrons, it is surrounded by water molecules. But when it gives up a fourth electron, some water molecules shift out of the way to let in sulfates. This dance costs energy, but understanding that energy loss paves the way for more efficient cerium batteries.
Image Credit: Dylan Herrera, Goldsmith Lab, University of Michigan

It turns out cerium flow batteries lose voltage when electrolyte molecules siphon off energy to form different complexes around the metal

An explanation for why flow batteries using the metal cerium in a sulfuric acid electrolyte fall short on voltage, discovered through a study led by the University of Michigan, could pave the way for better battery chemistry.

Flow batteries are one of the methods under consideration for storing intermittent sources of renewable electricity, such as solar and wind power. They can bank large quantities of energy by keeping the chemical potential in liquid form, with two electrolytes that flow through porous electrodes to charge and discharge. The metal cerium could store energy at a relatively high voltage, meaning more energy per metal ion, and at low cost.

One of the challenges with cerium is figuring out how to make electric charges transfer to and from the electrode efficiently. On its way through the positive electrode, cerium either picks up or drops off an electron, depending on whether the battery is charging or discharging.

However, the cerium in a sulfuric acid electrolyte doesn’t pick up and drop off the electron as quickly as expected, meaning energy is wasted. It turned out that the water molecules and sulfate molecules were doing a complicated dance around the cerium, and that’s how the energy was lost.

Breathing may measurably modulate neural responses across brain

Wenyu Tu, co-author on the eLife paper and doctoral student in neuroscience in the Huck Institutes of the Life Sciences, sets up a functional MRI experiment. Functional MRI was used in conjunction with neuronal electrophysiology to identify a link between respiration and neural activity changes.
Photo Credit: Kelby Hochreither/Penn State

Mental health practitioners and meditation gurus have long credited intentional breathing with the ability to induce inner calm, but scientists do not fully understand how the brain is involved in the process. Using functional magnetic resonance imaging (fMRI) and electrophysiology, researchers in the Penn State College of Engineering identified a potential link between respiration and neural activity changes in rats.

Their results were made available online ahead of publication in eLife. The researchers used simultaneous multi-modal techniques to clear the noise typically associated with brain imaging and pinpoint where breathing regulated neural activity.

“There are roughly a million papers published on fMRI — a non-invasive imaging technique that allows researchers to examine brain activity in real time,” said Nanyin Zhang, founding director of the Penn State Center for Neurotechnology in Mental Health Research and professor of biomedical engineering. “Imaging researchers used to believe that respiration is a non-neural physiological artifact, like a heartbeat or body movement, in fMRI imaging. Our paper introduces the idea that respiration has a neural component: It affects the fMRI signal by modulating neural activity.”

By scanning the brainwaves of rodents in a resting state under anesthesia using fMRI, researchers revealed a network of brain regions involved in respiration.

Growing pure nanotubes is a stretch, but possible

There are dozens of varieties of nanotubes, each with a characteristic diameter and structural twist, or chiral angle. Carbon nanotubes are grown on catalytic particles using batch production methods that produce the entire gamut of chiral varieties, but Rice University scientists have come up with a new strategy for making batches with a single, desired chirality. Their theory shows chiral varieties can be selected for production when catalytic particles are drawn away at specific speeds by localized feedstock supply. The illustration depicts this and an analogous process 19th-century scientists used to describe the evolution of giraffes’ long necks due to the gradual selection of abilities to reach progressively higher for food.
Credit: Illustrations by Ksenia Bets/Rice University

Like a giraffe stretching for leaves on a tall tree, making carbon nanotubes reach for food as they grow may lead to a long-sought breakthrough.

Materials theorists Boris Yakobson and Ksenia Bets at Rice University’s George R. Brown School of Engineering show how putting constraints on growing nanotubes could facilitate a “holy grail” of growing batches with a single desired chirality.

Their paper in Science Advances describes a strategy by which constraining the carbon feedstock in a furnace would help control the “kite” growth of nanotubes. In this method, the nanotube begins to form at the metal catalyst on a substrate, but lifts the catalyst as it grows, resembling a kite on a string.

Carbon nanotube walls are basically graphene, its hexagonal lattice of atoms rolled into a tube. Chirality refers to how the hexagons are angled within the lattice, between 0 and 30 degrees. That determines whether the nanotubes are metallic or semiconductors. The ability to grow long nanotubes in a single chirality could, for instance, enable the manufacture of highly conductive nanotube fibers or semiconductor channels of transistors.

Previously unseen processes reveal path to better rechargeable battery performance

Materials science and engineering postdoctoral researcher Wenxiang Chen is the first author of a new study that applies imaging techniques common in ceramics and metallurgy to rechargeable ion battery research. 
Photo by Fred Zwicky

To design better rechargeable ion batteries, engineers and chemists from the University of Illinois Urbana-Champaign collaborated to combine a powerful new electron microscopy technique and data mining to visually pinpoint areas of chemical and physical alteration within ion batteries.

A study led by materials science and engineering professors Qian Chen and Jian-Min Zuo is the first to map out altered domains inside rechargeable ion batteries at the nanoscale – a 10-fold or more increase in resolution over current X-ray and optical methods.

The findings are published in the journal Nature Materials.

The team said previous efforts to understand the working and failure mechanisms of battery materials have primarily focused on the chemical effect of recharging cycles, namely the changes in the chemical composition of the battery electrodes.

A new electron microscopy technique, called four-dimensional scanning transmission electron microscopy, allows the team to use a highly focused probe to collect images of the inner workings of batteries.

An easier way to remove medical devices

MIT engineers have shown that medical devices made from aluminum can be disintegrated within the body by exposing them to gallium-indium, a liquid metal that seeps into the boundaries between the grains of the metal.
Credit: MIT based on figures courtesy of the researchers

By taking advantage of a phenomenon that leads to fractures in metal, MIT researchers have designed medical devices that could be used inside the body as stents, staples, or drug depots, then safely broken down on demand when they’re no longer needed.

The researchers showed that biomedical devices made from aluminum can be disintegrated by exposing them to a liquid metal known as eutectic gallium-indium (EGaIn). In practice, this might work by painting the liquid onto staples used to hold skin together, for example, or by administering EGaIn microparticles to patients.

Triggering the disintegration of such devices this way could eliminate the need for surgical or endoscopic procedures to remove them, the researchers say.

“It’s a really dramatic phenomenon that can be applied to several settings,” says Giovanni Traverso, the Karl van Tassel Career Development Assistant Professor of Mechanical Engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital. “What this enables, potentially, is the ability to have systems that don’t require an intervention such as an endoscopy or surgical procedure for removal of devices.”

Traverso is the senior author of the study, which appears in Advanced Materials. Vivian Feig, an MIT postdoc, is the lead author of the paper.

Researchers develop superfast new method to manufacture high-performance thermoelectric devices

high-performance thermoelectric devices for energy harvesting and cooling
Source: University of Notre Dame

Yanliang Zhang, associate professor of aerospace and mechanical engineering at the University of Notre Dame, and collaborators Alexander Dowling and Tengfei Luo have developed a machine-learning assisted superfast new way to create high-performance, energy-saving thermoelectric devices.

The novel process uses intense pulsed light to sinter thermoelectric material in less than a second (conventional sintering in thermal ovens can take hours). The team sped up this method of turning nanoparticle inks into flexible devices by using machine learning to determine the optimum conditions for the ultrafast but complex sintering process.

The achievement was just published in the journal Energy and Environmental Science.

Flexible thermoelectric devices offer great opportunities for direct conversion of waste heat into electricity as well as solid-state refrigeration, Zhang said. They have additional benefits such as power sources and cooling devices — they don’t emit greenhouse gases, and they are durable and quiet since they don’t have moving parts.

A Brain Stimulator That Powers with Breath Instead of Batteries

UConn researchers have developed a way of charging deep brain stimulators that don't require the battery power that's currently standard
Credit/Source: University of Connecticut Contributed Illustration

Implantable deep brain stimulators can help many people with neurological and psychiatric disease when traditional treatments fail. But surgery every time the batteries need to be changed is a major drawback. Now, UConn researchers report in Cell Reports Physical Sciences a new way to charge the devices using a person’s own breathing movements.

Deep brain stimulators are becoming more common, with about 150,000 new devices implanted each year. They are normally placed under the skin in the chest area and their electrodes implanted within the brain. The electrodes zap the brain with electrical pulses multiple times per second to regulate the brain’s abnormal electrical activity. Deep brain stimulators can help people with Parkinson’s disease and other movement disorders to regain control over their muscle motions. Research has also shown the technique can significantly reduce the symptoms for psychiatric conditions such as treatment-resistant depression and obsessive-compulsive disorder.

Just like a pacemaker, deep brain stimulators are battery powered. While most pacemaker batteries last from 7-10 years, deep brain stimulator batteries typically require changing every 2-3 years because of their high energy consumption. And each battery change requires surgery.

UConn chemists Esraa Elsanadidy, Islam Mosa, James Rusling, and their collaborators have developed a deep brain stimulator that never needs its batteries changed.

New Tech Solves Longstanding Challenges for Self-Healing Materials

3D printed thermoplastic on woven-carbon fiber reinforcement.
Credit: North Carolina State University

Engineering researchers have developed a new self-healing composite that allows structures to repair themselves in place, without having to be removed from service. This latest technology resolves two longstanding challenges for self-healing materials, and can significantly extend the lifespan of structural components such as wind-turbine blades and aircraft wings.

“Researchers have developed a variety of self-healing materials, but previous strategies for self-healing composites have faced two practical challenges,” says Jason Patrick, corresponding author of the research paper and an assistant professor of civil, construction and environmental engineering at North Carolina State University.

“First, the materials often need to be removed from service in order to heal. For instance, some require heating in an oven, which can’t be done for large components or while a given part is in use. Second, self-healing only works for a limited period. For example, the material might be able to heal a few times, after which its self-repairing properties would significantly diminish. We’ve come up with an approach that addresses both of those challenges in a meaningful way, while retaining the strength and other performance characteristics of structural fiber-composites.”

Step by step

Berkeley researchers may be one step closer to making robot dogs our new best friends. Using advances in machine learning, two separate teams have developed cutting-edge approaches to shorten in-the-field training times for quadruped robots, getting them to walk — and even roll over — in record time.

In a first for the robotics field, a team led by Sergey Levine, associate professor of electrical engineering and computer sciences, demonstrated a robot learning to walk without prior training from models and simulations in just 20 minutes. The demonstration marks a significant advancement, as this robot relied solely on trial and error in the field to master the movements necessary to walk and adapt to different settings.

“Our work shows that training robots in the real world is more feasible than previously thought, and we hope, as a result, to empower other researchers to start tackling more real-world problems,” said Laura Smith, a Ph.D. student in Levine’s lab and one of the lead authors of the paper posted on arXiv.

In past studies, robots of comparable complexity required several hours to weeks of data input to learn to walk using reinforcement learning (RL). Often, they also were trained in controlled lab settings, where they learned to walk on relatively simple terrain and received precise feedback about their performance.

Borrowing a shape from a to-go cup lid, a drone wing could learn how to sense danger faster

Researchers have discovered a new possible use for the dome shape that you would find on a to-go cup lid.
Credit: Pexels/Caleb Oquendo

The oddly satisfying small domes that you press on your soda’s to-go cup lid may one day save a winged drone from a nosedive.

Patterns of these invertible domes on a drone’s wings would give it a way to remember in microseconds what dangerous conditions feel like and react quickly. The study, conducted by researchers at Purdue University and the University of Tennessee, Knoxville, is among the first demonstrations of a metamaterial that uses its shape to learn how to adapt to its surroundings on its own. The paper is published in the journal Advanced Intelligent Systems.

Unlike humans and other living beings, autonomous vehicles lack ways to filter out information they don’t need, which slows their response time to changes in their environment.

“There’s this problem called ‘data drowning.’ Drones cannot use their full flight capability because there is just too much data to process from their sensors, which prevents them from flying safely in certain situations,” said Andres Arrieta, a Purdue associate professor of mechanical engineering with a courtesy appointment in aeronautical and astronautical engineering.

Dome-covered surfaces that can sense their surroundings would be a step toward enabling a drone’s wings to feel only the most necessary sensory information. Because it only takes a certain minimum amount of force to invert a dome, forces below this threshold are automatically filtered out. A specific combination of domes popped up and down at certain parts of the wing, for example, could indicate to the drone’s control system that the wing is experiencing a dangerous pressure pattern. Other dome patterns could signify dangerous temperatures or that an object is approaching, Arrieta said.

Molecular cage protects precious metals in catalytic converters

Stable catalyst illustration
Source/Credit: Slac National Accelerator Laboratory

Sometimes, solutions to environmental problems can have environmentally unfriendly side effects. For example, while most gas-powered cars have a catalytic converter that transforms engine emission pollutants into less harmful gases, this comes with a tradeoff: Catalytic converters contain precious metals such as platinum and palladium.

The good thing about these precious metals is that they act as catalysts that help break down pollutants, with a suite of properties that make them the best elemental candidates for this chemical job. But they are also rare, which makes them expensive, and extracting them from the earth produces its own pollution.

However, in a paper published October 24 in Nature Materials, researchers at the SUNCAT Center for Interface Science and Catalysis and the Precourt Institute for Energy at Stanford University and the Department of Energy’s SLAC National Accelerator Laboratory reported a way of encapsulating catalysts that could reduce the number of precious metals catalytic converters need to work, which could in turn reduce the practice of precious metal mining.

“I think the material we made could knock down the number of precious metals used in a catalytic converter by 50 precent, which would mean a lot once you multiply that by the nearly 1.5 billion cars we now have in circulation on the planet,” said Matteo Cargnello, the new study's senior author and an assistant professor of chemical engineering at Stanford University.

Microscopy reveals how psychedelics light up brain’s neuropathways

 Alex Kwan, Ph.D. ‘09, associate professor in the Meinig School of Biomedical Engineering, is using optical microscopy and other tools to map the brain’s neural response to psychedelic drugs, an approach that could lead to the development of fast-acting antidepressants
Photo credit: Ryan Young/Cornell University.

What a long, strange trip it’s been for psychedelic drugs. From their use in ancient indigenous ceremonies, to their often-caricatured association with the 1960s counterculture, to their recent reemergence as a potential therapeutic, hallucinogens have been embraced by very different communities for very different reasons. But scientists have never fully understood how these drugs actually work on the brain.

Alex Kwan, Ph.D. ‘09, associate professor in the Meinig School of Biomedical Engineering in the College of Engineering, is using optical microscopy and other tools to map the brain’s neural response to these psychoactive chemicals, an approach that could eventually lead to the development of fast-acting antidepressants and treatments for substance-use disorders and cluster headaches.

“We know more about the pharmacology, how psychedelics work at the structural level, interacting with the brain receptors. But there has been a big void in terms of understanding what they do to the brain itself, at the neural circuit level,” Kwan said. “There’s a chain of events that happen that ultimately lead to acute and longer-lasting behavioral changes that might be useful for treatment. But in between a lot of that is a black box.”

Despite the renewed interest in the benefits of psychedelics from popular figures such as environmentalist and author Michael Pollan, much of the research into these drugs was conducted in the 1950s and 60s with fairly rudimentary methods, Kwan said.

Penguin feathers may be secret to effective anti-icing technology

Gentoo penguins
Photo Credit: 66 north

Ice buildup on powerlines and electric towers brought the northern US and southern Canada to a standstill during the Great Ice Storm of 1998, leaving many in the cold and dark for days and even weeks. Whether it is on wind turbines, electric towers, drones, or airplane wings, dealing with ice buildup typically depends on techniques that are time consuming, costly and/or use a lot of energy, along with various chemicals. But, by looking to nature, McGill researchers believe that they have found a promising new way of dealing with the problem. Their inspiration came from the wings of Gentoo penguins who swim in the ice-cold waters of the south polar region, with pelts that remain ice-free even when the outer surface temperature is well below freezing.

We initially explored the qualities of the lotus leaf, which is very good at shedding water but proved less effective at shedding ice,” said Anne Kietzig, who has been looking for a solution for close to a decade. She is an associate professor in Chemical Engineering at McGill and the director of the Biomimetic Surface Engineering Laboratory. “It was only when we started investigating the qualities of penguin feathers that we discovered a material found in nature that was able to shed both water and ice.”

A laser that could ‘reshape the landscape of integrated photonics’

A team of researchers led by Qiang Lin, a professor of electrical and computer engineering at Rochester, has developed the first multi-color integrated laser that emits high-coherence light at telecommunication wavelengths, allows laser-frequency tuning at record speeds, and is the first narrow linewidth laser with fast configurability at the visible band.
Credit: University of Rochester / J. Adam Fenster

How do you integrate the advantages of a benchtop laser that fills a room onto a semiconductor chip the size of a fingernail?

A research team co-led by Qiang Lin, a professor of electrical and computer engineering at the University of Rochester, has set new milestones in addressing this challenge, with the first multi-color integrated laser that:

• Emits high-coherence light at telecommunication wavelengths
• Allows laser-frequency tuning at record speeds
• Is the first narrow linewidth laser with fast configurability at the visible band

The project, described in Nature Communications, was co-led by John Bowers, distinguished professor at University of California/Santa Barbara, and Kerry Vahala, professor at the California Institute of Technology. Lin Zhu, professor at Clemson University, also collaborated on the project.

Model calculates the energetics of piercing fangs, claws and other biological weapons

A new model can be used to calculate the forces involved when one organism stabs another with its puncturing tools. Pictured: A viper skull.
Photo by L. Brian Stauffer

Researchers have created a model that can calculate the energetics involved when one organism stabs another with its fangs, thorns, spines or other puncturing parts. Because the model can be applied to a variety of organisms, it will help scientists study and compare many types of biological puncturing tools, researchers said. It also will help engineers develop new systems to efficiently pierce materials or resist being pierced.

The new findings are reported in the Journal of the Royal Society Interface.

“The idea behind this was to come up with a quantitative framework for comparing a variety of biological puncture systems with each other,” said Philip Anderson, a University of Illinois Urbana-Champaign professor of evolution, ecology and behavior who led the research with postdoctoral researcher Bingyang Zhang. “An initial question of this research was how do we even measure these different systems to make them comparable.”

How evolution overshot the optimum bone structure in hopping rodents

A bipedal jerboa, one of the rodent species included in a study of unpredictability in animal movements.
 Image credit: Talia Moore and Kim Cooper

Bones that are separate in small jerboas are fully fused in large ones, but the bone structures that are best at dissipating the stresses of jumping are only partially fused

Foot bones that are separate in small hopping rodents are fused in their larger cousins, and a team of researchers at the University of Michigan and University of California, San Diego, wanted to know why.

It appears that once evolution set jerboa bones on the path toward fusing together, they overshot the optimum amount of fusing—the structure that best dissipated stresses from jumping and landing—to become fully bonded.

This finding could inform the design of future robotic legs capable of withstanding the higher forces associated with rapid bursts of agile locomotion.

Jerboas are desert rodents that hop erratically on two legs to avoid predators. Across the jerboa family tree, these two legs can look a lot different: there are species that weigh just three grams to those that weigh 400 grams, with heavier species sporting vastly different bones of the feet, or metatarsals. Lighter jerboas are like most other mammals, including humans: their metatarsal foot bones are separate from each other.

Ink flows to meet surging demand for national security research

Student interns are introduced to Sandia National Laboratories’ superfuge by test operations engineer Orlando Abeyta during a tour. Several new agreements signed this year are expected to increase the numbers of students and faculty partnering with Sandia to support its growing national security workload.
Photo credit: Craig Fritz

The nation’s largest national laboratory is embarking on a major expansion of its network of academic partners to meet the surging demand for national security science and engineering.

This year, Sandia National Laboratories inked memoranda of understanding with Texas A&M University; the University of California, Berkeley; North Carolina State University and the University of Texas at El Paso. It is finalizing agreements with Arizona State University and the University of Washington. When those are signed, Sandia will have formal ties with 27 universities, including 13 minority serving institutions.

Work at Sandia, which is performed almost entirely for federal agencies, has been rising steadily. From fiscal year 2015 to fiscal year 2021, the Labs’ budget increased more than 50%, from $2.9 billion to $4.5 billion. Over the same period, the Labs increased its workforce by more than 25%, from 11,700 to 15,000.

But Sandia won’t meet its obligations just by hiring staff.

“Partnering with universities keeps Sandia science at the state of the art and enables us to do more research for our national security mission than we can on our sites alone,” said Diane Peebles, Sandia’s senior manager of academic programs.

Digging deep

The unassuming Pacific mole crab, Emerita analoga, is about to make some waves. UC Berkeley researchers have debuted a unique robot inspired by this burrowing crustacean that may someday help evaluate the soil of agricultural sites, collect marine data and study soil and rock conditions at construction sites.

In a study published today in Frontiers in Robotics & AI, Hannah Stuart, assistant professor of mechanical engineering, and her team demonstrated one of the first legged robots that can self-burrow vertically. This digging robot, called EMBUR (EMerita BUrrowing Robot), uses a novel leg design to achieve downward motion that emulates the way Pacific mole crabs bury themselves in beach sand.

Mole crabs make burrowing look easy, but, according to Laura Treers, the study’s lead author and a Ph.D. student in mechanical engineering in Stuart’s Embodied Dexterity research group, it is difficult to move downward through granular media, like sand and soil. The deeper an animal digs, the harder the grains push back, impeding excavation.

To overcome this challenge and create a vertical-legged burrower, the researchers designed the legs of the robot to have an anisotropic force response, which means that they experience much greater force in one direction than another. Like a swimmer, the soft fabric legs of this robot expand for large forces during the power stroke, but fold and retract during the return stroke.

Designing a plant cuticle in the lab could yield many benefits

Yandeau-Nelson inside her lab
Photos credit Christopher Gannon | Iowa State University

Scientists are working to bioengineer a common defense mechanism that most plants develop naturally to protect against drought, insects and other environmental stresses.

The goal is to identify the genetic structure of a plant cuticle and create a roadmap for breeding plants with designer cuticles that can respond to changing climates. The cuticle is a thin, waxy layer that provides a physical barrier between the plant and its environment. The work also has potential biorenewable applications for developing value-added chemicals with industrial functions.

Marna Yandeau-Nelson, an associate professor of genetics, development and cell biology at Iowa State University, is leading the cross-disciplinary team that includes researchers from Iowa State, the University of Delaware and University of Nebraska-Lincoln. The project, which is funded by a $2.65-million National Science Foundation grant, includes a unique partnership with Iowa State’s Science Bound program to provide research opportunities for underrepresented students.

“If we understand what genes are required for certain compositions and what compositions of the cuticle protect against different stresses, then we have the ability for applied breeding for the production of designer cuticles with important protective functions,” Yandeau-Nelson said.

As ransomware attacks increase, new algorithm may help prevent power blackouts

Saurabh Bagchi, a Purdue professor of electrical and computer engineering, develops ways to improve the cybersecurity of power grids and other critical infrastructure.
Credit: Purdue University photo/Vincent Walter

Millions of people could suddenly lose electricity if a ransomware attack just slightly tweaked energy flow onto the U.S. power grid.

No single power utility company has enough resources to protect the entire grid, but maybe all 3,000 of the grid’s utilities could fill in the most crucial security gaps if there were a map showing where to prioritize their security investments.

Purdue University researchers have developed an algorithm to create that map. Using this tool, regulatory authorities or cyber insurance companies could establish a framework that guides the security investments of power utility companies to parts of the grid at greatest risk of causing a blackout if hacked.

Power grids are a type of critical infrastructure, which is any network – whether physical like water systems or virtual like health care record keeping – considered essential to a country’s function and safety. The biggest ransomware attacks in history have happened in the past year, affecting most sectors of critical infrastructure in the U.S. such as grain distribution systems in the food and agriculture sector and the Colonial Pipeline, which carries fuel throughout the East Coast.