Researchers mimic a mystery of nature to make ice move on its own

Virginia Tech

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Ph.D. student Jack Tapocik sets up ice on an engineered surface in the lab of Jonathan Boreyko.

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Credit: Photo by Alex Parrish for Virginia Tech.

In Associate Professor Jonathan Boreyko’s Nature-Inspired Fluids and Interfaces Lab, Ph.D. student Jack Tapocik watched a disc-shaped chunk of ice resting on an engineered metal surface. As the ice melted, the water formed a puddle beneath.

Even after many seconds of melting, the ice disk remained adhered to the engineered surface. At first, Tapocik was tempted to conclude that nothing would happen, but he waited. His patience paid off. After a minute, the ice slingshot across the metal plate he designed, gliding along as if it was propelled supernaturally.

The results are important because they have a host of potential applications. The methods team members developed lay the foundation for rapid defrosting and novel methods of energy harvesting. Their work has now been published in "ACS Applied Materials & Interfaces."

Looking to Death Valley

The team was inspired by a naturally occurring phenomenon at Racetrack Playa in Death Valley, California. This dry lake bed in Death Valley National Park is host to a ghostly display of boulders the size of watermelons that make long trails in the cracked earth, left behind by their apparent movement. Because the ground was level and many of the rocks were flat, the reason for their migration remained a mystery until recently.

Harvard University Professor Richard Norris found out why this happened in 2014. Rather than a supernatural occurrence, it was a combination of hard ground, rain, ice, and wind. Rainfall covered the ground with water, but the hardness of the ground prevented the water from being absorbed. This water froze when the temperature dropped, and as it later started to melt, the resulting ice rafts drifted in the breeze for the rocks to “sail” across the meltwater. Some of the rocks have been seen traveling together, which gave rise to the “racetrack” mythos.

While Norris solved a mystery of the rocks, Boreyko’s team was seeking something new: Its members wanted to create a surface that would propel melting ice all by itself, without any wind required. They wanted to harness the science of the racing rocks.

Building the track

Initially conceived by Boreyko and former graduate student Saurabh Nath back in 2019, the experiments took three years to complete with two more years needed for the model.

Boreyko’s team cut asymmetric grooves into aluminum plates. This herringbone pattern, which looks like a series of arrowhead-shaped channels, causes the underlying meltwater to flow in one direction. 

“This directional flow of meltwater carried the ice disk along with it,” said Tapocik. “A good analogy is tubing on a river except here, the directional channels cause the flow instead of gravity.” 

Out of curiosity, team members tried coating the aluminum herringbones with a water-repellant spray. They expected to simply see a faster version of the disk getting propelled by the flow, but surprisingly, the disk stuck to the surface instead. This is what led to the discovery of the slingshot effect.

“On a waterproof surface, the excess meltwater above the channels gets squeezed out very easily,” Boreyko said. “This makes the ice disk stick to the surface’s ridges. The meltwater is still flowing along the channels, but the ice can’t ride along anymore. The fun trick here is that as the meltwater flows beyond the front edge of the ice disk, it creates a puddle. Having a flat puddle on one side of the ice creates a mismatch in surface tension, which dislodges the ice and causes it to shoot across the surface.”

By comparison, the movement of the “racing” rocks in Death Valley is quite slow, and they don't shoot like slingshots. It’s not likely to become an official competition, but Boreyko’s surfaces are winning over the Racetrack Playa for having the fastest ice on earth.

Boreyko has already imagined one of the most high-impact applications: energy harvesting. In that scenario, he brings back the idea of the racing rocks.

“If the surface structure were patterned in a circle rather than a straight line, the melting object would continually rotate,” he said. “Now imagine putting magnets on top of the ice, rather than boulders. These magnets would also rotate, which could be used for power generation.”  

In addition to Boreyko and Tapocik, other research colleagues were involved in this project:

• Saurabh Nath, a graduate student at the beginning of the project, recently hired into a tenure-track position at the University of Pennsylvania
• Sarah Propst, an undergraduate researcher at the beginning of the project, now a Ph.D. student at Johns Hopkins University
• Venkata Yashasvi Lolla, a graduate student who is now a postdoctoral research associate at UC Berkeley

John R. Jones III and the John Jones Faculty Fellowship supported this work. 

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Journal

ACS Applied Materials & Interfaces

Article Publication Date

14-Aug-2025

 

KIER develops high-performance electrodes for seawater electrolysis to produce hydrogen

Despite precious metals making up only 1% of the catalyst weight in the electrode, hydrogen production efficiency improved by 1.3 times compared to conventional methods.

National Research Council of Science & Technology

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Catalyst Developed by the Research Team

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Credit: KOREA INSTITUTE OF ENERGY RESEARCH(KIER)

Dr. Ji-Hyung Han’s research team from the Convergence Research Center of Sector Coupling & Integration at the Korea Institute of Energy Research (President Yi, Chang-Keun, hereinafter “KIER”) has developed a high-performance carbon cloth-based electrode that maintains stable performance even under high current conditions. The newly developed electrode is the first seawater electrolysis electrode using a carbon cloth support that has demonstrated successful continuous operation for over 800 hours under high current conditions, highlighting its potential for commercialization.

Water electrolysis is an eco-friendly technology that produces hydrogen by splitting water. Although it primarily relies on freshwater, growing concerns over global water scarcity have drawn increasing attention to seawater electrolysis, which uses seawater directly.

The performance and lifespan of seawater electrolysis systems depend heavily on the catalyst used in the electrode and the electrode support that evenly distributes the catalyst. While precious metal-based catalysts such as platinum and ruthenium are commonly used, recent research has focused on non-precious metal catalysts or approaches that minimize the use of precious metals due to cost concerns.

There are also issues with the electrode support. Metal-based supports are highly vulnerable to corrosion caused by chloride ions, clearly limiting their lifespan. As an alternative, carbon cloth has emerged due to its excellent electrical conductivity, corrosion resistance, flexibility, and cost-effectiveness. However, existing carbon cloth-based catalysts have faced challenges in commercialization, as they suffer from performance degradation and structural damage during high-current operation (above 500 mA/cm²) and long-term use over 100 hours, which are required for industrial applications.

The research team overcame the limitations of conventional electrodes by developing a carbon cloth-based electrode with enhanced hydrogen production efficiency through an optimized acid treatment process. The newly developed electrode reduced the overpotential applied to the electrode by 25%, enabling a 1.3 times more efficient hydrogen evolution reaction (HER) compared to existing electrodes.

To enhance the reactivity of the electrode, the research team focused on acid-treating the carbon cloth. The acid treatment involves immersing the cloth in a highly concentrated nitric acid solution at 100°C for one hour. However, evaporation during the process caused fluctuations in acid concentration, which posed a challenge. To address this, the team designed a specialized acid treatment vessel that prevents concentration changes, successfully optimizing the surface treatment of the carbon cloth support.

The acid-treated carbon cloth support exhibits high hydrophilicity, which promotes the uniform distribution of cobalt, molybdenum, and ruthenium ions across its surface. In particular, the precious metal ruthenium is evenly dispersed throughout the support, enabling excellent electrochemical performance even with a minimal amount.

As a result, the ruthenium-incorporated cobalt-molybdenum (CoMo) catalyst achieved a roughly 25% reduction in overpotential compared to conventional CoMo catalysts, despite using only about 1% ruthenium by weight. By lowering the required overpotential, the catalyst enabled a hydrogen evolution reaction that is approximately 1.3 times more efficient at the same current density.

The catalyst-coated electrode maintained its initial performance even after over 800 hours of continuous operation under high current conditions of 500 mA/cm². Post-operation analysis of the electrode revealed no leaching of metal ions such as ruthenium and cobalt into the electrolyte, indicating excellent corrosion resistance and structural stability. Additionally, the team successfully synthesized a large-area electrode measuring 25 cm², showing potential for scalability and practical application.

Dr. Ji-Hyung Han of KIER stated, “This technology marks the world’s first successful case of long-term operation over one month under industrial-level high current conditions in seawater electrolysis using a carbon cloth-based electrode.” She added, “We plan to further advance the technology to the demonstration level through extended durability testing beyond 1,000 hours and research on scaling up to large-area cell modules and stacks.”

 

This research was supported by the National Research Council of Science & Technology (NST) under the Ministry of Science and ICT. The results were published in the May 2025 online edition of the prestigious international journal Applied Surface Science (Elsevier).

Testing of Seawater Electrolysis Stack Incorporating the Research Team’s Developed Electrode

Schematic of the Electrode Fabrication Process Using the Developed Catalyst 

Credit

KOREA INSTITUTE OF ENERGY RESEARCH(KIER)

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Journal

Applied Surface Science

DOI

10.1016/j.apsusc.2025.163534 

Article Title

Ru-modified CoMoOx catalyst on carbon cloth for efficient HER in alkaline seawater electrolysis at high current densities

 

Research alert: Study finds that school-based online surveillance companies monitor students 24/7

University of California - San Diego

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A recent study from researchers at University of California San Diego is the first detailed assessment of companies offering school-based online surveillance services such as social media monitoring, student communications monitoring and online activity monitoring to middle and high schools. Schools pay for the services directly or may request federal grant funding to cover the costs. 

Originally intended to support students’ mental health and prevent adverse school events, such as school shootings, the study found that school-based online surveillance companies are extensively monitoring students’ digital behavior, both during and outside of school hours, often using artificial intelligence (AI) with little human oversight or transparency. The study did not delve into success metrics on the original intention of these companies.

The research team identified 14 companies actively marketing online surveillance services frequently beyond school-issued devices and outside of school premises, raising concerns about privacy, equity and oversight.

Key findings include:

• 86% of companies monitor students 24 hours per day and 7 days per week, not just during school hours.

• 71% use AI for automated flagging of “concerning activity;” only 43% use human review teams. The definition of “concerning activity” was not generally clearly defined by the companies but typically appeared to include topics such as suicidal ideation and violence.

• 93% monitor school-issued devices; 36% also claim to monitor student-owned phones and computers but did not clarify if they monitor all activity on students’ personal devices.

• 29% generate student “risk scores” based on online behavior, which can be viewed at the student, classroom or school level.

Companies cited a variety of ways they gain access to student digital activity, including browser plug-ins, API integrations and device software. Further, the study found that companies rarely disclose pricing or performance data, and public-facing information is often vague or incomplete. Many companies collect and flag sensitive data, including students’ private messages and search histories. Some provide dashboards to administrators, after-hours alert systems and even direct crisis intervention, such as contacting law enforcement. However, most companies offer little to no public information about their algorithms, potential error rates or bias mitigation strategies.

The authors suggest that further research is needed on the prevalence of monitoring adoption across U.S. schools as well as how teachers and school administrators respond to alerts provided by the monitoring.

The study was published on July 8, 2025, in Journal of Medical Internet Research and was led by Cinnamon S. Bloss, Ph.D., professor at the UC San Diego Herbert Wertheim School of Public Health and Human Longevity Science and the director of the Center for Empathy and Technology, situated within the UC San Diego Sanford Institute for Empathy and Compassion. Alison O’Daffer, student in the San Diego State University - UC San Diego Joint Doctoral Program in clinical psychology, is the first author of the study.

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Journal

Journal of Medical Internet Research

DOI

10.2196/71998 

 

International “State of the Climate” report confirms record-high greenhouse gases, global temperatures, global sea level, and ocean heat in 2024

American Meteorological Society

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Geographical distribution of selected notable climate anomalies and events in 2024. (Fig. 1.1 in The State of the Climate in 2024.)

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Credit: "The State of the Climate in 2024" (c) American Meteorological Society, 2025

According to the 35th annual State of the Climate report, greenhouse gas concentrations, the global temperature across land and oceans, global sea level, and ocean heat content all reached record highs in 2024, and glaciers lost the most ice of any year on record.

The international review of the world’s climate, published by the Bulletin of the American Meteorological Society (BAMS), is based this year on contributions from 589 scientists in 58 countries. For decades, the State of the Climate has provided the most comprehensive annual update on Earth’s climate⁠ — illuminating not only key indicators like global CO2 but also notable weather events, regional phenomena, and other data collected by environmental monitoring stations and instruments located on land, water, and ice, as well as in space.

“The State of the Climate report is an annual scientific landmark,” says American Meteorological Society President David J. Stensrud. “It is a truly global effort, in which hundreds of researchers from universities, government agencies, and more come together to provide a careful, rigorously peer-reviewed report on our planet’s climate. High-quality observations and findings from all over the world are incorporated, underscoring the vital importance of observations to monitor, and climate science to understand, our environment. The results affirm the reality of our changing climate, with 2024 global temperatures reaching record highs."  

Notable findings from the international report include:

• Earth’s greenhouse gas concentrations were the highest on record. Carbon dioxide (CO2), methane, and nitrous oxide ⁠— Earth’s major atmospheric greenhouse gases⁠ — once again reached record-high concentrations in 2024. The globally averaged CO2 level reached 422.8±0.1 parts per million, a 52% increase from the pre-industrial level of ~278 ppm. Annual growth in global mean CO2 has increased from 0.6±0.1 ppm yr−1 in the early 1960s to an average of 2.4 ppm yr−1 during 2011–20. The growth from 2023 to 2024 was 3.4 ppm, equal with 2015/16 as the highest in the record since the 1960s.

• Record temperatures were notable across the globe. A new annual global surface temperature record was set for the second year in a row, with records dating back as far as the mid-1800s. A range of scientific analyses indicate that the annual global surface temperature was 1.13 to 1.30 degrees F (0.63 to 0.72 degrees C) above the 1991–2020 average. A strong El Niño that began in mid-2023 and ended in boreal spring 2024 contributed to the record warmth. The last time two consecutive years reached a new global surface temperature record was in 2015 and 2016, when a strong El Niño developed during the latter half of 2015 and dissipated by May 2016. All six major global temperature datasets used for analysis in the report agree that the last 10 years (2015–24) were the 10 warmest on record. 

• The water cycle continued to intensify. Higher global temperatures impacted the water cycle. Water evaporation from land in the Northern Hemisphere reached one of the highest annual values on record. The global atmosphere contained the largest amount of water vapor on record, with over one-fifth of the globe recording their highest values in 2024. This far exceeded 2023, where only one-tenth of the globe experienced record-high values of total column water vapor. Precipitation was globally high; 2024 was the third-wettest year since records began in 1983. Extreme rainfall, as characterized by the annual maximum daily rainfall over land, was the wettest on record. In April, Dubai in the United Arab Emirates recorded 9.8 in (250 mm) of rain in 24 hours — nearly three times its annual average.

• El Niño conditions contributed to record-high sea surface temperatures. Strong El Niño conditions in the equatorial Pacific Ocean that emerged by the end of 2023 continued into early 2024, with neutral conditions returning in boreal spring. Daily globally averaged sea surface temperatures were at record-high levels from the beginning of 2024 until late June. The mean annual global sea surface temperature in 2024 was a record high, surpassing the previous record of 2023 by 0.11 of a degree F (0.06 of a degree C). Approximately 91% of the ocean surface experienced at least one marine heatwave in 2023, which is defined as sea surface temperatures in the warmest 10% of all recorded data in a particular location for at least five days. Only 26% of the ocean surface experienced at least one marine cold spell. The ocean experienced a record-high global average of 100 marine heatwave days and a new record low of nine marine cold spell days.

• Ocean heat and global sea level were the highest on record. Over the past half-century, the oceans have stored more than 90% of the excess energy trapped in Earth’s system by greenhouse gases and other factors. The global ocean heat content, measured from the ocean’s surface to a depth of 2000 m (approximately 6561 ft), continued to increase, and reached new record highs in 2024. Global mean sea level was a record high for the 13th consecutive year, reaching about 4.0 in (105.8 mm) above the average for 1993 when satellite altimetry measurements began. Warming oceans have contributed an average of 1.5±0.3 mm to the rise per year since 2005, while melt from ice sheets and glaciers have contributed an average of 2.1±0.4 mm during that same period.

• The Arctic saw near-record warmth. The Arctic had its second-warmest year in the 125-year record, with autumn (October to December) having been record warm. During the summer, an intense August heatwave brought all-time record-high temperatures to parts of the northwest North American Arctic, and record-high August monthly mean temperatures at Svalbard Airport reached more than 52°F (11°C). In September, temperatures above 86°F (30°C) were observed in Norway, marking the latest time of the year in the observational record that such high temperatures have occurred there. During the 2023/24 snow season, there were large differences in how long snow remained on the ground, from the shortest to date in the twenty-first century over parts of Canada to at or near the longest in this century in parts of the Nordic and Asian Arctic. The Arctic maximum sea ice extent in 2024 was the second smallest in the 46-year satellite record, while the minimum sea ice extent was the sixth smallest. 

• Antarctica saw continued low sea ice. Following record lows in 2023, net sea ice extent was larger than last year but continued to be well below average during much of 2024. The Antarctic daily minimum and maximum sea ice extents for the year were each the second lowest on record behind 2023, marking a continuation of low and record-low sea ice extent since 2016.

• Glaciers around the world continued to melt. For the second consecutive year, all 58 global reference glaciers across five continents lost mass in 2024, resulting in the greatest average ice loss in the 55-year record. In South America, Venezuela became the first Andes country to register the loss of all glaciers. In Colombia, the Conejeras Glacier was declared extinct, joining the list of glaciers that have disappeared in recent years. 

• Tropical cyclone activity was below average, but storms still set records around the globe. A total of 82 named tropical cyclones were observed during the Northern and Southern Hemispheres’ storm seasons, below the 1991–2020 average of 87 and equal to the number recorded in 2023. Many storms made landfall and some caused major damage. Hurricane Helene brought destruction from Florida to the southern Appalachian Mountains. The storm caused devastating record flooding that contributed to over 200 deaths, the most in the United States since Hurricane Katrina in 2005. Hurricane Milton impacted Florida’s Gulf Coast just 12 days after Helene affected the region, marking the shortest time between major (Category 3 or higher) hurricane landfalls in Florida. In the northwest Pacific basin, Super Typhoon Yagi became one of the most destructive storms to affect China and Vietnam in recent years, causing more than 800 fatalities.

The State of the Climate report is a peer-reviewed series published annually as a special supplement to the Bulletin of the American Meteorological Society. The American Meteorological Society makes the full report openly available online. 

About the American Meteorological Society

The American Meteorological Society (www.ametsoc.org) advances the atmospheric and related sciences, technologies, applications, and services for the benefit of society. Founded in 1919, AMS has a membership of around 12,000 professionals, students, and weather enthusiasts. AMS publishes 12 scientific journals in the atmospheric and related oceanic and hydrologic sciences; sponsors more than 12 conferences annually; and offers numerous programs and services to the weather, water, and climate community

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Journal

Bulletin of the American Meteorological Society

New research reveals the spark that ignites Mediterranean marine heatwaves

CMCC Foundation - Euro-Mediterranean Center on Climate Change

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The Mediterranean Sea is particularly susceptible to marine heatwaves – such as the record breaking 2022 heatwave which was characterized by anomalously high sea surface temperatures – due to the interplay of air-sea heat fluxes and local oceanographic processes, leading to significant impacts on marine ecosystems and coastal communities. 

A new study, led by CMCC, brings the scientific community one step closer to identifying the driving forces behind these events. Analyzing over hundreds of marine heatwave events identified through advanced satellite data and clustering analysis, the study shows that persistent subtropical ridges – intrusions of warm air from over the African continent into Europe, often informally referred to as African anticyclones – do far more than simply raise air temperatures. 

While subtropical ridges occur frequently in summer, roughly every 2 days, their persistence is what creates the critical conditions for marine heatwave formation. During marine heatwave onset, ridge occurrence becomes persistent – the high-pressure system associated with the ridge becomes stationary, disrupting the normal eastward movement of weather systems.

When these ridges settle over the Mediterranean basin for five consecutive days or more, they cause the prevailing winds to still, which then leads the sea to stop shedding heat and surface waters warm rapidly.

“Our study identifies the favourable conditions leading up to marine heatwaves and reveals that they are triggered by persistent subtropical ridges which weaken strong winds in the area,” says CMCC researcher and co-author of the study Ronan McAdam.

The findings demonstrate that 63.3%, 46.4%, and 41.3% of marine heatwaves in the Western, Central, and Eastern Mediterranean respectively occur during periods with both subtropical ridges and reduced wind conditions – a remarkable concentration considering these combined conditions only occur during 8.6% to 14.6% of all summer days.

When subtropical ridges persist for several days, the resulting decrease in wind speeds causes a substantial reduction in heat loss from the ocean to the atmosphere. This heat loss accounts for over 70% of the total heat flux in affected regions, and drives the majority of the ocean temperature change. 

"It is very satisfying to identify the mechanics behind a phenomena we have been studying for years," says lead author Giulia Bonino.

Furthermore, likelihood ratios across three Mediterranean clusters – 26 events in the Western Mediterranean, 18 in the Central Mediterranean, and 14 in the Eastern Mediterranean – reveal that when a subtropical ridge and weak winds strike together, a heatwave is four to five times more likely to form. 

The discovery of this statistical relationship provides the foundation for more accurate prediction systems that could help protect vulnerable marine ecosystems and dependent industries from future extreme events. For example, in the Gulf of Lion subsurface temperatures climbed by almost 7°C over just two days during the most extreme events, illustrating the dramatic speed at which marine heatwaves can develop and the need for accurate predictions and effective responses. 

"This was a great collaboration between oceanographers and atmospheric scientists – joining expertise and passion counts," remarks co-author Ronan McAdam. By combining the subtleties of meteorology with high-resolution ocean data, the team shows that early-warning systems can move beyond temperature thresholds to embrace the physics that actually triggers an event.

With Mediterranean seas warming faster than the global average, knowing with accuracy when a marine heatwave is about to strike is essential. “Our work highlights previously unidentified processes that are essential for accurately representing Mediterranean MHWs,” says McAdam. “These results are critical to improving forecast systems and Earth system models, representing a key step toward effective early-warning and mitigation strategies in the basin.”

 

For more information:

The study's innovative approach combines hierarchical clustering analysis with ERA5 reanalysis data at high resolution to identify common patterns across the basin. The work emerges from CMCC's in-house dataset on marine heatwaves, and feeds directly into the EU Horizon ObsSea4Clim project. This work will be used to guide future developments of CMCC’s models, including the CMCC's Mediterranean Forecasting System, which is available and used by a wide range of stakeholders across the region.

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Journal

Nature Geoscience

DOI

10.1038/s41561-025-01762-9 

Article Title

Mediterranean summer marine heatwaves triggered by weaker winds under subtropical ridges

Article Publication Date

14-Aug-2025

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