Fast-charging lithium battery seeks to eliminate ‘range anxiety’

Peer-Reviewed Publication

CORNELL UNIVERSITY

ITHACA, N.Y. – Cornell University engineers have created a new lithium battery that can charge in under five minutes – faster than any such battery on the market – while maintaining stable performance over extended cycles of charging and discharging.

The breakthrough could alleviate “range anxiety” among drivers who worry electric vehicles cannot travel long distances without a time-consuming recharge.

“Range anxiety is a greater barrier to electrification in transportation than any of the other barriers, like cost and capability of batteries, and we have identified a pathway to eliminate it using rational electrode designs,” said Lynden Archer, professor of engineering and dean of Cornell’s College of Engineering, who oversaw the project. “If you can charge an EV battery in five minutes, I mean, gosh, you don’t need to have a battery that’s big enough for a 300-mile range. You can settle for less, which could reduce the cost of EVs, enabling wider adoption.”

The team’s paper, “Fast-Charge, Long-Duration Storage in Lithium Batteries,” published in Joule. The lead author is Shuo Jin, a doctoral student in chemical and biomolecular engineering.

Lithium-ion batteries are among the most popular means of powering electric vehicles and smartphones. The batteries are lightweight, reliable and relatively energy-efficient. However, they take hours to charge, and lack the capacity to handle large surges of current.

The researchers pinpointed indium as an exceptionally promising material for fast-charging batteries. Indium is a soft metal, mostly used to make indium tin oxide coatings for touch-screen displays and solar panels.

The new study shows indium has two crucial characteristics as a battery anode: an extremely low migration energy barrier, which sets the rate at which ions diffuse in the solid state; and a modest exchange current density, which is related to the rate at which ions are reduced in the anode. The combination of those qualities – rapid diffusion and slow surface reaction kinetics – is essential for fast charging and long-duration storage.

“The key innovation is we’ve discovered a design principle that allows metal ions at a battery anode to freely move around, find the right configuration and only then participate in the charge storage reaction,” Archer said. “The end result is that in every charging cycle, the electrode is in a stable morphological state. It is precisely what gives our new fast-charging batteries the ability to repeatedly charge and discharge over thousands of cycles.”

That technology, paired with wireless induction charging on roadways, would shrink the size – and the cost – of batteries, making electric transportation a more viable option for drivers.

However, that doesn’t mean indium anodes are perfect, or even practical.

“While this result is exciting, in that it teaches us how to get to fast-charge batteries, indium is heavy,” Archer said. “Therein lies an opportunity for computational chemistry modeling, perhaps using generative AI tools, to learn what other lightweight materials chemistries might achieve the same intrinsically low Damköhler numbers. For example, are there metal alloys out there that we’ve never studied, which have the desired characteristics? That is where my satisfaction comes from, that there’s a general principle at work that allows anyone to design a better battery anode that achieves faster charge rates than the state-of-the art technology.”

The research was supported by the U.S. Department of Energy Basic Energy Sciences Program through the Center for Mesoscale Transport Properties, an Energy Frontiers Research Center. The researchers made use of the Cornell Center for Materials Research, which is supported by the National Science Foundation’s Materials Research Science and Engineering Center program.

For additional information, see this Cornell Chronicle story.

Cornell University has dedicated television and audio studios available for media interviews.

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JOURNAL

Joule

DOI

10.1016/j.joule.2023.12.022 

ARTICLE TITLE

Fast-charge, long-duration storage in lithium batteries

ARTICLE PUBLICATION DATE

16-Jan-2024

 

Chemists use the blockchain to simulate over 4 billion chemical reactions essential to the origins of life

CELL PRESS

Cryptocurrency is usually “mined” through the blockchain by asking a computer to perform a complicated mathematical problem in exchange for tokens of cryptocurrency. But in research appearing in the journal Chem on January 24, a team of chemists have repurposed this process, asking computers to instead generate the largest network ever created of chemical reactions which may have given rise to prebiotic molecules on early Earth.

This work indicates that at least some primitive forms of metabolism might have emerged without the involvement of enzymes, and it shows the potential to use blockchain to solve problems outside the financial sector that would otherwise require the use of expensive, hard to access supercomputers.

“At this point we can say we exhaustively looked for every possible combination of chemical reactivity that scientists believe to had been operative on primitive Earth,” says senior author Bartosz A. Grzybowski (http://grzybowski-group.net/default.asp) of the Korea Institute for Basic Science and the Polish Academy of Sciences.

To generate this network, the researchers chose a set of starting molecules likely present on early Earth, including water, methane, and ammonia, and set rules about which reactions could occur between different types of molecules. They then translated this information into a language understandable by computers and used the blockchain to calculate which reactions would occur over multiple expansions of a giant reaction network.

“The computer takes the primordial molecules and the accepted prebiotic chemistries. We coded it into the machine, and then we released it onto the world,” says Grzybowski.

Grzybowski’s team worked with chemists and computer-specialists at Allchemy, a company that uses AI for chemical synthesis planning, to generate the network using Golem, a platform that orchestrates portions of the calculations over hundreds of computers across the world, which receive cryptocurrency in exchange for computing time.

The resulting network, termed NOEL for the Network of Early Life, started off with over 11 billion reactions, which the team narrowed down to 4.9 billion plausible reactions. NOEL contains parts of well-known metabolic pathways like glycolysis, close mimics of the Krebs cycle, which organisms use to generate energy, and syntheses of 128 simple biotic molecules like sugars and amino acids.

Curiously, of the 4.9 billion reactions generated, only hundreds of reaction cycles could be called “self-replicating,” which means that the molecules produce additional copies of themselves. Self-replication has been postulated to be central to the emergence of life, but the vast majority of its known manifestations require complex macromolecules like enzymes.   

“Our results mean that with only small molecules present, self-amplification is a rare event. I don’t think that this type of self-replication was operative on primitive earth, before larger molecular structures were somehow formed,” says Grzybowski. “We see emergence of primitive metabolism, but we don’t see self-replication, so maybe self-replication appeared later in evolution.”

“If you asked me two years ago, I’d be thinking we’d need years for this type of work,” says Grzybowski. “But for a fraction of the cost, in two or three months, we finished a task of 10 billion reactions, 100k times bigger than we did previously.”

This work not only advances what we know about early prebiotic chemistry, but it also demonstrates how science can be made more accessible to researchers at smaller universities and institutions.

“Our system of education is based on elite universities mostly in the western world. It’s very hard for the developing world to even compete with these universities because they don’t have access to supercomputers,” says Grzybowski. “But if you can distribute computing in this way for a fraction of the cost, you can give other people opportunities to play.”

While the network generated in this work was performed on hundreds of computers around the world, Grzybowski suggests that this method can be used at institutions without having to pay out cryptocurrency tokens to the computers performing the calculations.

“With a platform like Golem you can connect your institution’s network and harness the entire idle power of its computers to perform calculations,” says Grzybowski. “You could create this computing infrastructure without any capital expenditure.”

Grzybowski hopes that repurposing the blockchain in this way can revolutionize the way we perform large scale calculations across the world and change how we see the value of cryptocurrency.

“I hope people in computer science can figure out how can we tokenize cryptocurrencies in some way that can benefit global science,” says Grzybowski. “Maybe society could be happier about using cryptocurrencies, if you could tell people that in the process we could discover new laws of biology or some new cancer drug,” says Grzybowski.

###

Development of all codes and algorithms described in this work described was supported by internal funds of Allchemy, Inc. and Golem Factory, GmbH. Analysis of pathways and writing of the paper by Bartosz Grzybowski was supported by the Institute for Basic Science, Korea. Grzybowski has no financial stake in Golem although he is a stakeholder of Allchemy. Additional information about declarations of interest can be found in the paper.

Chem, Roszak et al. “Emergence of metabolic-like cycles in blockchain-orchestrated reaction networks” https://cell.com/chem/fulltext/S2451-9294(23)00611-3

Chem (@Chem_CP) is the first physical science journal published by Cell Press. A sister journal to Cell, Chem, which is published monthly, provides a home for seminal and insightful research and showcases how fundamental studies in chemistry and its sub-disciplines may help in finding potential solutions to the global challenges of tomorrow. Visit https://www.cell.com/chem. To receive Cell Press media alerts, contact press@cell.com. 

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JOURNAL

Chem

DOI

10.1016/j.chempr.2023.12.009 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Emergence of metabolic-like cycles in blockchain-orchestrated reaction networks.

ARTICLE PUBLICATION DATE

24-Jan-2024

Chemistry professor R. Graham Cooks expands research of water droplet interfaces that offer the secret ingredient for building life

Peer-Reviewed Publication

PURDUE UNIVERSITY

R. Graham Cooks, the Henry B. Hass Distinguished Professor of Chemistry, and his postdoctoral researcher Lingqi Qiu have experimental evidence that the key step in protein formation can occur in droplets of pure water, and have recently published these findings in the Proceedings of the National Academy of Sciences (PNAS).

In this key step, amino acids are dehydrated (they lose water) even though they are in a water solution, a paradox that is resolved by the fact that these droplet surfaces are unusually dry and highly acidic. Under these conditions, amino acids connect to each other to create peptides, a fundamental step toward forming proteins and, eventually, living organisms.

A crucial aspect of the discovery is that the natural "left-handed" structure of amino acids is maintained throughout this process. This leads to the formation of pure chiral peptides with the same "L" handedness. The authors identified a specific compound, oxazolidinone, as a crucial intermediate in this reaction. 

Further, they found that this dehydration reaction is not confined to microscopic droplets. It also happens on a larger, centimeter scale, as demonstrated in a lab experiment starting from the oxazolidinone intermediate. This larger-scale reaction mirrors the microdroplet chemistry and is also analogous to the well-studied wet-dry cycles that are suggested to occur in hydrothermal pools and seashores. This connection links peptide formation in aerosols and in more extensive, prebiotic environments. 

The study adds to the body of evidence that the surface of water drops represents a uniquely active physical and chemical system. Present are very high electric fields and extreme acidity that drives dehydration of amino acids to form peptides. Studies of the chemistry at water droplet interfaces offer new insights into the early stages of life's chemical evolution. 

The authors acknowledge valuable discussions with Purdue research associates Dylan T. Holden and Nicolás M. Morato. They also acknowledge the financial support from the Multidisciplinary University Research Initiative of the Air Force Office of Scientific Research (FA9550-21-1-0170) via Stanford University (sub-award 62741613-204669) and also support from the National Science Foundation (grant CHE-1905087).

Related Link: The fountain of life: Water droplets hold the secret ingredient for building life

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JOURNAL

Proceedings of the National Academy of Sciences

DOI

10.1073/pnas.2309360120 

ARTICLE TITLE

Oxazolone mediated peptide chain extension and homochirality in aqueous microdroplets

 

Syphilis-like diseases were already widespread in America before the arrival of Columbus

Peer-Reviewed Publication

UNIVERSITY OF BASEL

 

IMAGE: 

SKELETON AT THE SITE IN JUBUICABEIRA II, BRAZIL.

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CREDIT: PHOTO: DR. JOSE FILIPPINI

Researchers at the Universities of Basel and Zurich have discovered the genetic material of the pathogen Treponema pallidum in the bones of people who died in Brazil 2,000 years ago. This is the oldest verified discovery of this pathogen thus far, and it proves that humans were suffering from diseases akin to syphilis – known as treponematoses – long before Columbus’s discovery of America. The new findings, published in the scientific journal Nature, call into question previous theories concerning the spread of syphilis by the Spanish conquistadors.

The history of the emergence and spread of infectious diseases was of great importance for global health even before the Covid-19 pandemic. With modern laboratory methods, researchers can now detect the tiniest traces of DNA from pathogens in prehistoric finds. That means they can trace back how these pathogens spread historically and their evolutionary development.

An international research group led by Professor Verena Schünemann from the University of Basel, formerly at the University of Zurich, in collaboration with ETH Zurich and the Universities of Vienna and Sao Paulo, examined prehistoric bones belonging to four individuals who died 2,000 years ago in the coastal region of Santa Caterina in Brazil. For some of the individuals visible pathological changes to the prehistoric bones were detected which could indicate that the deceased were suffering from an illness similar to syphilis.

Prehistoric DNA from bones dating over 2,000 years old

The researchers used dentists’ drilling tools to remove minuscule samples of bone under sterile conditions. From those samples they isolated prehistoric genetic material (ancient DNA) belonging to the syphilis pathogen. Their study, published in the renowned scientific journal Nature, demonstrates that all the bacterial genomes that have been investigated can be attributed to the Treponema pallidum endemicum strain – that is, the pathogen that leads to bejel.

Treponematoses are a group of infectious diseases that includes the sexually transmitted disease syphilis. While syphilis as a venereal disease presents a global health risk, bejel, which is spread by skin contact, only occurs today in very arid regions of Africa and Asia.

“Our study has been able to show that endemic syphilis was already present in humid zones of Brazil around 2,000 years ago,” says Schünemann. This means that people were already becoming infected with endemic syphilis, probably via skin contact, more than 1,000 years before the arrival of Columbus in the New World.

Syphilis-like diseases originated pre-Columbus

Intense debates are still ongoing today among specialists and medical historians concerning whether Christopher Columbus’s sailors and soldiers brought sexually transmitted syphilis from the New World to the Old upon their return in 1492. The illness spread rapidly from the end of the 15th century onwards, particularly in harbor towns.

“The fact that the findings represent an endemic type of treponemal diseases, and not sexually transmitted syphilis, leaves the origin of the sexually transmitted syphilis still unsettled,” says Kerttu Majander, postdoctoral researcher at the University of Basel and one of the lead authors of the study. However, the authors consider that there is a lot to suggest that treponematoses were already widespread in Europe before Columbus’s time.

“As we have not found any sexually transmitted syphilis in South America, the theory that Columbus brought syphilis to Europe seems to appear more improbable,” agrees Schünemann. In point of fact, earlier discoveries by her group, for example in Finland and Poland, suggest that some forms of treponematoses already existed in Europe too.

Recombination could have driven the development of syphilis-like diseases

Many species of bacteria exchange traits that are of evolutionary benefit via what is known as horizontal gene transfer, or recombination. A comparison between the prehistoric DNA in the bones from Brazil and today’s pathogens shows that such recombination events have indeed taken place. “We cannot pinpoint exactly when this exchange took place, but it is probably one of the driving mechanisms in the divergence between the subspecies that cause different treponemal infections,” says Marta Pla-Díaz of the University of Basel, the other lead author of the study.

The DNA comparison also allows the date of the Treponema pallidum family’s emergence to be deduced. Their investigations show that these pathogens have arisen at some point between 12,000 and 550 BCE. The history of these pathogens therefore stretches much further back than previously assumed.

“Although the origin of syphilis still leaves room for imagination, at least we now know beyond a doubt that treponematoses were no strangers to the American inhabitants who lived and died centuries before the continent was explored by Europeans,” concludes Schünemann. She and her team are confident that advances in the analysis of prehistoric DNA could also lead to the discovery of the origin of venereal syphilis.

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JOURNAL

Nature

DOI

10.1038/s41586-023-06965-x 

ARTICLE TITLE

Redefining the treponemal history through pre-Columbian genomes from Brazil

ARTICLE PUBLICATION DATE

24-Jan-2024

 

Groundwater levels are sinking ever faster around the world

Peer-Reviewed Publication

ETH ZURICH

 

IMAGE: 

GROUNDWATER-​FED IRRIGATION BY AN ELECTRICITY-​OPERATED PUMP IN SOUTHWESTERN BANGLADESH.

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CREDIT: PHOTOGRAPH: AHMED ZIAUR RAHMAN

At the beginning of November, The New York Times ran the headline, “America is using up its groundwater like there’s no tomorrow.” The journalists from the renowned media outlet had published an investigation into the state of groundwater reserves in the United States. They came to the conclusion that the United States is pumping out too much groundwater.

But the US isn’t an isolated case. “The rest of the world is also squandering groundwater like there’s no tomorrow,” says Hansjörg Seybold, Senior Scientist in the Department of Environmental Systems Science at ETH Zurich. He is coauthor of a study that has just been published in the journal Nature.

Scientific evidence of rapidly depleting water resources

Together with researchers from the University of California, Santa Barbara (UCSB), he has corroborated the journalists’ worrying findings. It is not only in North America that far too much groundwater is being pumped out, but also in other parts of the world where humans have settled.

In an unprecedented feat of painstaking effort, the researchers have compiled and analysed data from over 170,000 groundwater monitoring wells and 1,700 groundwater systems over the past 40 years.

This measurement data shows that in recent decades, humans have massively expanded groundwater extraction worldwide. The water level in most groundwater-​bearing rock layers, known as aquifers, has fallen drastically almost everywhere in the world since 1980. And since 2000, this decline in groundwater reserves has accelerated. The effects are most pronounced in aquifers in the world’s arid regions, including California and the High Plains in the US, along with Spain, Iran, and Australia.

“We weren’t surprised that groundwater levels have fallen sharply worldwide, but we were shocked at how the pace has picked up in the past two decades,” Seybold says.

One of the reasons Seybold cites for the accelerated drop in groundwater levels in arid regions is that people use these areas intensively for agriculture and are pumping (too) much of the groundwater to the surface to irrigate crops, for example in California’s Central Valley.

Food cultivation and climate change exacerbate the problem

Moreover, the world’s population is growing, which means more food needs to be produced, for example in the arid regions of Iran. This is one of the countries where groundwater reserves have fallen the most.

But climate change is also exacerbating the groundwater crisis: some areas have become drier and hotter in recent decades, meaning agricultural crops need to be irrigated more heavily. Where climate change is driving a decline in precipitation, groundwater resources recover more slowly, if at all.

Heavy rainfall, which is occurring more frequently in some places as a result of climate change, is also not of any help. If the water comes in huge quantities, the soil often cannot absorb it. Instead, the water drains off at the surface without seeping into the groundwater. This problem is particularly acute in places with a high level of soil sealing, such as large cities.

Trend can be reversed

“The study also reveals good news,” says co-​author Debra Perrone. “Aquifers in some areas have recovered in places where there have been policy changes or where alternative sources of water are available for direct use or for recharging the aquifer.”

One of the positive examples is the Genevese aquifer, which supplies drinking water to around 700,000 people in the canton of Geneva and the neighbouring French department of Haute-​Savoie. Between 1960 and 1970, its level fell drastically because both Switzerland and France were pumping out water in an uncoordinated manner. Some wells even dried up and had to be closed.

To preserve the shared water resource, politicians and authorities in both countries agreed to replenish the aquifer artificially with water from the Arve River. The intention was first to stabilise the groundwater level and later to raise it – and the intervention was a success. “While the water level in this aquifer may not have returned to its original level, the example shows that groundwater levels don’t always have to go only one way: down,” Seybold says.

Other countries are reacting, too

The authorities have also had to take action in other countries: In Spain, a large pipeline has been built to carry water from the Pyrenees to central Spain, where it feeds the Los Arenales aquifer. In Arizona, water is diverted from the Colorado River into other bodies of water to replenish the groundwater reservoirs – although this does cause the delta of the Colorado River to dry up at times.

“Such examples are a ray of hope,” says UCSB researcher and lead author Scott Jasechko. Nevertheless, he and his colleagues are urgently calling for more measures to combat the depletion of groundwater supplies. “Once heavily depleted, aquifers in semi-​deserts and deserts may require hundreds of years to recover because there’s simply not enough rainfall to swiftly replenish these aquifers,” Jasechko says.

There is an additional danger on the coasts: if the groundwater level falls below a certain level, seawater can invade the aquifer. This salinises the wells, leaving the water that is pumped up unusable neither for drinking water nor for irrigating fields; trees whose roots reach into the flow of groundwater die. On the east coast of the US, there are already extensive ghost forests with not a single living tree.

“That’s why we can’t put the problem on the back burner,” Seybold says. “The world must take urgent action.”

The world has a problem: On all inhabited continents, groundwater resources whose levels have fallen to various degrees are marked by light to dark red zones.

CREDIT

(Illustrations: Scott Jasechko, UCSB)

JOURNAL

Nature

DOI

10.1038/s41586-​023-06879-8 

ARTICLE TITLE

Rapid groundwater declines in many aquifers globally but cases of recovery

ARTICLE PUBLICATION DATE

24-Jan-2024

Global groundwater depletion is accelerating, but is not inevitable

Aquifers are declining worldwide, put success stories highlight that proactive management can reverse these trends

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA BARBARA

 

IMAGE: 

THIS PAPER PROVIDES THE MOST COMPREHENSIVE ACCOUNT YET OF TRENDS IN GROUNDWATER LEVELS AROUND THE WORLD. DARKER COLORS INDICATE CHANGES OF 10 CM/YEAR OR MORE.

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CREDIT: JASECHKO ET AL.

(Santa Barbara, Calif.) — Groundwater is rapidly declining across the globe, often at accelerating rates. Writing in the journal Nature, UC Santa Barbara researchers present the largest assessment of groundwater levels around the world, spanning nearly 1,700 aquifers. In addition to raising the alarm over declining water resources, the work offers instructive examples of where things are going well, and how groundwater depletion can be solved. The study is a boon for scientists, policy makers and resource managers working to understand global groundwater dynamics.

“This study was driven by curiosity. We wanted to better understand the state of global groundwater by wrangling millions of groundwater level measurements,” said lead author Debra Perrone, an associate professor in UC Santa Barbara’s Environmental Studies Program.

The team compiled data from national and subnational records and the work of other agencies. The study took three years, two of which were spent just cleaning and sorting data. That’s what it takes to make sense of 300 million water level measurements from 1.5 million wells over the past 100 years.

Next came the task of translating the deluge of data into actual insights about global groundwater trends. The researchers then scoured over 1,200 publications to reconstruct aquifer boundaries in the regions of inquiry and evaluate groundwater level trends in 1,693 aquifers.

Their findings provide the most comprehensive analysis of global groundwater levels to date, and demonstrate the prevalence of groundwater depletion. The work revealed that groundwater is dropping in 71% of the aquifers. And this depletion is accelerating in many places: the rates of groundwater decline in the 1980s and ’90s sped up from 2000 to the present, highlighting how a bad problem became even worse. The accelerating declines are occurring in nearly three times as many places as they would expect by chance.

Groundwater deepening is more common in drier climates, with accelerated decline especially prevalent in arid and semi-arid lands under cultivation — “an intuitive finding,” said co-lead author Scott Jasechko, an associate professor in the university’s Bren School of Environmental Science & Management. “But it’s one thing for something to be intuitive. It’s quite another to show that it’s happening with real-world data.”

On the other hand, there are places where levels have stabilized or recovered. Groundwater declines of the 1980s and ’90s reversed in 16% of the aquifer systems the authors had historical data for. However, these cases are only half as common as would be expected by chance.

“This study shows that humans can turn things around with deliberate, concentrated efforts,” Jasechko said.

Take Tucson, Arizona for instance. Water allotted from the Colorado River is used to replenish the aquifer in the nearby Avra Valley. The project stores water for future use. “Groundwater is often viewed as a bank account for water,” Jasechko explained. “Intentionally refilling aquifers allows us to store that water until a time of need.” 

Communities can spend a lot of money building infrastructure to hold water above ground. But if you have the right geology, you can store vast quantities of water underground, which is much cheaper, less disruptive and less dangerous. The stored groundwater can also benefit the region’s ecology. In fact, while preparing a research brief in 2014, Perrone found that aquifer recharge can store six times more water per dollar than surface reservoirs.

Tucson’s groundwater recharge is a boon for the local aquifer; however, withdrawals have caused the mighty river to dwindle above ground. The Colorado rarely reaches its delta in the California Gulf anymore. “These groundwater interventions can have tradeoffs,” Jasechko acknowledged.

Another option is to focus on reducing demand. Often this involves regulations, permitting and fees for groundwater use, Perrone explained. To this end, she is currently examining water law in the western U.S. to understand these diverse interventions. Regardless of whether it comes from supply or demand, aquifer recovery seemed to require intervention, the study revealed.

The authors complemented measurements from monitoring wells with data from the Gravity Recovery and Climate Experiment (GRACE). The GRACE mission consists of twin satellites that precisely measure the distance between them as they orbit the Earth. In this way, the crafts detect small fluctuations in the planet’s gravity, which can reveal the dynamics of aquifers at large scales.

“The beauty of GRACE is that it allows us to explore groundwater conditions where we don’t have in-situ data,” Perrone said. “Our assessment complements GRACE. Where we do have in-situ data, we can explore groundwater conditions locally, a crucial level of resolution when you’re managing depletion.” This local resolution is critical, as the authors found out, because adjacent aquifers can display different trends.

That said, groundwater level trends don’t present the whole picture. Even where aquifers remain stable, withdrawing groundwater can still affect nearby streams and surface water, causing them to leak into the subsurface, as Perrone and Jasechko detailed in another Nature paper in 2021. 

The authors also analyzed precipitation variability over the past four decades for 542 aquifers. They found that 90% of aquifers where declines were accelerating are in places where conditions have gotten drier over the last 40 years. These trends have likely reduced groundwater recharge and increased demand. On the other hand, climate variability can also enable groundwater to rebound where conditions become wetter.

This study of monitoring wells complements a paper Perrone and Jasechko released in 2021. That study represented the largest assessment of global groundwater wells, and made the cover of the journal Science. “The monitoring wells are telling us information about supply. And the groundwater wells are telling us information about demand,” Perrone said.

“Taken together, they allow us to understand which wells have run dry already, or are most likely to run dry if groundwater-level declines occur,” Jasechko added.

Perrone and Jasechko are now examining how groundwater levels vary over time in the context of climate change. Connecting these rates of change to the depths of actual wells will provide better predictions of where groundwater access is at risk.

“Groundwater depletion is not inevitable,” Jasechko said. Fine resolution, global studies will enable scientists and officials to understand the dynamics of this hidden resource.

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JOURNAL

Nature

DOI

10.1038/s41586-023-06879-8 

ARTICLE TITLE

Rapid groundwater declines in many aquifers globally but cases of recovery

ARTICLE PUBLICATION DATE

24-Jan-2024

 

Uncovering the secrets behind the silent flight of owls

Researchers investigate the aeroacoustic mechanisms that allow owls to fly silently using numerical simulations

Peer-Reviewed Publication

CHIBA UNIVERSITY

 

IMAGE: 

THE MICRO-FRINGES ON OWL WINGS EFFECTIVELY SUPPRESS THE NOISE WHILE MAINTAINING THE AERODYNAMIC PERFORMANCE OF THE WINGS COMPARABLE TO THAT OF A WING WITHOUT THE FRINGES.

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CREDIT: HAO LIU FROM CHIBA UNIVERSITY

Owls are fascinating creatures that can fly silently through some of the quietest places. Their wings make no noise while flying, enabling them to accurately locate their prey using their exceptional hearing ability while remaining undetected. This unique ability depends on many factors and has long been a hot research subject.

Studies have found associations between the ability to fly silently and the presence of micro-fringes in owl wings. These trailing-edge (TE) fringes play a crucial role in suppressing the noise produced by wing flap-induced air movement. 

Studying these fringes can lead to the development of promising methods to reduce noise caused by fluid machinery. While many studies have evaluated these fringes using flat plates and airfoils, their exact mechanisms and effects on the interactions of feathers and the different wing features in real owl wings remained unknown.

To unravel the secrets of silent owl wings, Professor Hao Liu with his colleagues, including Dr. Jaixin Rong from the Graduate School of Engineering and Dr. Yajun Jiang and Dr. Masashi Murakami from the Graduate School of Science at Chiba University in Japan, investigated how TE fringes influence both the sound and aerodynamic performance of owl wings. 

When asked about the motivation behind their study, Prof. Liu says, “Despite many efforts by many researchers, exactly how owls achieve silent flight is still an open question. Understanding the precise role of TE fringes in their silent flight will enable us to apply them in developing practical low-noise fluid machinery.” Their findings were published in the journal Bioinspiration & Biomimetics on November 17, 2023.

To understand how owl wings work, the team constructed two three-dimensional models of a real owl wing—one with and the other without TE fringes—with all its geometric characteristics. They used these models to conduct fluid flow simulations that combined the methods of large eddy simulations and the Ffowcs-Williams-Hawkings analogy. The simulations were conducted at the speed of the gliding flight of approach of a real owl.
 
Simulations revealed that the TE fringes reduced the noise levels of owl wings, particularly at high angles of attack, and maintained aerodynamic performance comparable to owl wings without fringes. The team identified two complementary mechanisms through which the TE fringes influence airflow. First, the fringes reduce the fluctuations in airflow by breaking up the trailing edge vortices. Second, they reduce the flow interactions between feathers at the wingtips, thereby suppressing the shedding of wingtip vortices. Synergistically, these mechanisms enhance the effects of TE fringes, improving both aerodynamic force production and noise reduction.
 
Emphasizing the significance of these results, Prof. Liu says, “Our findings demonstrate the effect of complex interactions between the TE fringes and the various wing features, highlighting the validity of using these fringes for reducing noise in practical applications such as drones, wind turbines, propellers and even flying cars.”
 
Overall, this study deepens our understanding of the role of TE fringes in the silent flight of owls and can inspire biomimetic designs that could lead to the development of low-noise fluid machinery.

About Professor Hao Liu
Dr. Hao Liu is a Professor at the Graduate School of Engineering at Chiba University, Japan. Prof. Liu leads the Center for Aerial Intelligent Vehicles at Chiba University. He obtained his Ph.D. from Yokohama National University in 1992. Prof. Liu has over 600 publications and 11,200 citations to his name (Google Scholar). He is one of the world’s top 2% scientists, according to Stanford University (2023). His research interests include biomechanics, biomimetics, and bio-inspired engineering.

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JOURNAL

Bioinspiration & Biomimetics

DOI

10.1088/1748-3190/ad0aa9 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Trailing-edge fringes enable robust aerodynamic force production and noise suppression in an owl wing model