Aurelia Butler

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    How an Indigenous community in Panama is escaping rising seas

    In pictures from high above, the island of Gardi Sugdub resembles a container shipyard — small, brightly colored dwellings are jammed together cheek to jowl. At ground level, the island, one of more than 350 in the San Blas archipelago off the northern coast of Panama, is hot, flat and crowded. More than 1,000 people occupy the narrow dwellings that cover virtually every bit of the 150-by-400-meter island, which is slowly being swallowed by rising seas driven by climate change.

    This year, about 300 families from Gardi Sugdub are expected to begin moving to a new community on the mainland. The resettlement plan was initiated by the residents there more than a decade ago when they could no longer deny that the island couldn’t accommodate the growing population. Rising seas and intense storms are only making the predicament more dire.

    Many of the older adults will opt to stay put. Some still don’t believe climate change poses a threat, but 70-year-old Pedro Lopez is not among them. Lopez, whose cousin interpreted for him during our Zoom interview, currently shares a small house with 16 family members and the family dog. He doesn’t plan to move. He knows Gardi Sugdub, translated as Crab Island, along with many others in the archipelago, is going underwater, but he believes it won’t happen within his lifetime.

    The Indigenous Guna people have occupied these Caribbean islands since around the mid-1800s, when they abandoned the coastal jungle area near what is now the Panama-Colombia border to establish better trade and escape disease-carrying pests. Now, they are among the estimated hundreds of millions of people worldwide who by the end of the century may be forced to flee their land because of rising sea levels (SN: 5/9/20 & 5/23/20, p. 22).

    In the Caribbean, sea level rise currently averages around 3 to 4 millimeters per year. As global temperatures continue to rise, it is expected to hit 1 centimeter per year or more by century’s end.

    All of the islands of the San Blas archipelago will eventually be underwater and uninhabitable, says Steven Paton, who directs the Physical Monitoring Program at the Smithsonian Tropical Research Institute in Panama. “Some may need to be abandoned very soon while others not for many decades,” he adds.

    Anthropologist Anthony Oliver-Smith of the University of Florida in Gainesville has studied people who are forced from their homes by disasters for more than 50 years. Around the world, he says, climate change has become a major driver of displacement, with people who have limited resources facing the worst of it.

    The impacts of climate change — flooding, rising seas and erosion — are threatening the Tuvaluans in the South Pacific, the Mi’Kmaq of Prince Edward Island in Canada and the Shinnecock Indian Nation of New York. Half of some 1,600 remaining tribe members there still occupy a more than 300-hectare territorial homeland on Long Island surrounded by multimillion-dollar Southampton mansions.

    The Guna relocation is being closely watched as a possible template for other threatened communities. What sets the Guna apart from many others is that they have a place to go.

    Rising sea levels in Guna Yala

    More than 30,000 Indigenous Guna inhabit the province now called Guna Yala, which includes the archipelago once known as San Blas and a strip of mainland. Most live on the islands, traveling back to the mainland to get water from the mouth of the river there, and in some cases to tend crops. Some of the islands sit several meters above average sea level, but the vast majority are uninhabited spits of land with palm trees, many only a meter or less above sea level.

    So far, only the residents of Gardi Sugdub are included in the relocation plan.

    The Guna people of the islands are sustained by the biodiversity there. The sea, mangroves and nearby mainland forests provide food, medicine and building materials. The men hunt and fish to provide seafood to the best restaurants in Panama City, and agriculture remains part of the economy. Guna communities elect traditional authorities known as sailas (“chiefs” in Guna) and argars (“chief’s spokesmen”), and they hold regular meetings to address community issues.

    In recent decades, the Guna have moved toward an economy based on tourism and providing services to outsiders. They earn money supplying food, souvenirs and cultural artifacts to tourists but allow visitors to the islands only with prior approval from the sailas. Outsiders are not permitted to own property or operate businesses.

    Carlos Arenas is an international human rights lawyer and an adviser on social and climate justice issues. When he visited Gardi Sugdub in 2014 as a consultant for Displacement Solutions, a nonprofit initiative focused on housing, land and property rights, he was tasked to assess the nascent relocation plans and provide recommendations. He was shocked to see the visible threat posed by the rising sea. “You cannot see much elevation,” Arenas says. “The level of exposure was extremely high, but they don’t see it necessarily that way. They have been living there for more than 170 years.”

    Heliodora Murphy grew up on Gardi Sugdub and has watched the ocean rise higher each year. The 52-year-old grandmother doesn’t understand those who dismiss climate change in light of the growing physical evidence all around. Murphy, also speaking through an interpreter, recalls her father bringing rocks and sand from a river on the mainland to shore up pathways and keep their home dry.

    Gardi Sugdub resident Pedro Lopez, left, plans to stay on the island, while Heliodora Murphy, right, has already picked out her new home on the mainland.COURTESY OF IVETTE N. ROGERS

    Arenas says that some families face a daily struggle against the ocean. They build barriers that are immediately destroyed and have to be built again.

    Some of the stopgap measures have been counterproductive, like filling in coral reefs to expand the land area. Reefs are a natural buffer against wave action, storm surges, flooding and erosion. Destroying them has only added to the peril.

    Today, Murphy says, storm surges carry water into her small, ground-level home. “It’s very different than in the past,” she says. “The waves are so much higher now.” About two years ago, she decided she’d move with her family. “We can’t stay here.”

    A history of autonomy

    Historically, the Guna have had a level of autonomy rare among Indigenous people. When the Spanish conquistadors arrived in what is now Colombia and Panama, the Guna lived primarily near the Gulf of Urabá on the northern coast of Colombia. The two groups clashed violently, prompting the Guna to abandon the coastal border area and move north into the jungle of Panama near the Caribbean. By the mid-1800s, entire villages had relocated again, this time to the San Blas archipelago.

    Panama declared its independence from Spain in 1821 and became a part of Gran Colombia. Throughout the 19th century, the Guna lived independently according to their customs. That changed in 1903 when Panama broke from Colombia. The new nation attempted to assimilate the people living on the archipelago.

    But having escaped Spanish rule centuries earlier and avoided Colombian authority as well, the Guna resisted Panama’s acculturation efforts. When the Guna couldn’t achieve détente through other means, they launched an armed attack against the Panamanians in February 1925.

    The United States, having occupied the Panama Canal Zone since 1903, had geopolitical interests in the region and threw its support behind the Guna. That support forced the Panamanian government into a negotiated peace that allowed the Guna to continue their way of life. In 1938, the Guna islands and adjacent coastline were recognized as a semiautonomous Indigenous territory, Guna Yala. The Guna have maintained control of that territory since.

    The Guna find a new home

    The Gardi Sugdub residents first broached the idea of relocation in 2010. “They basically ran out of room,” Oliver-Smith says.

    He describes the Guna as the Indigenous people in Latin America who have been perhaps most successful in defending their cultural heritage, language and territory. They initiated the plans for resettlement and made arrangements among themselves to set aside 17 hectares of property on the mainland for these purposes. The land, within the Guna Yala territory, is near a school and health center being built by the Panamanian government.

    The residents of Gardi Sugdub (the island is shown here in 2014) face overcrowding and rising seas. More than a decade ago, they initiated a plan to move more than 300 families to a new community on the mainland.ARNULFO FRANCO/AP PHOTO

    When Guna leaders approached the government, the Ministry of Housing initially promised to build 50 houses on the parcel. But it remained just that — a promise — until around 2014, when the Guna began to speak publicly about their situation. News of their predicament caught the attention of Indigenous rights organizations and eventually Displacement Solutions, which turned to Arenas and Oliver-Smith to evaluate the situation and offer recommendations about the best way forward.

    Following Displacement Solutions’ first report in 2014, Panama’s Ministry of Housing agreed to build 300 houses, along with the hospital and school. But Arenas, who until the COVID-19 pandemic started had visited Guna Yala every year or so, says progress remained slow, causing the Guna to question Panama’s commitment to the relocation. The Guna leveraged support from international groups and members of the Panamanian government to get the project moving. “They were the originators of the idea of resettlement,” Oliver-Smith says. “And they kept it alive.”

    Arenas estimates that roughly 200 of the 300 houses in the new community are complete. The cost for the houses, which are being paid for by the Panamanian government, exceeds $10 million, and the Inter-American Development Bank has invested $800,000 in technical assistance. The new homes will have cement floors, bamboo walls, zinc roofs, running water and full electrification.

    Before plans to relocate began, many Guna had already moved to cities including Panama City and Colón for school, work or simply to have more room. Arenas expects that many more people already living in mainland Panama will likely join their families in the new community. People on other Guna Yala islands will likely have to move eventually too.

    Murphy has already picked out her two-bedroom home for her small nuclear family of seven. Two daughters moved to Panama City years ago, and she hopes to see them more. But at around 40 square meters, the homes may not accommodate the typical multigenerational, double-digit Guna families. Lopez plans to stay on the island, letting the younger generations live in the family’s new home on the mainland.

    The Guna hope to retain their traditional customs through the move, including handiwork called wini and molas (examples shown).DIXON HAMBY/MOMENT/GETTY IMAGES PLUS

    To ensure that the ethnic and cultural identities they fought to preserve are not lost in the move, the Guna plan to develop programs to teach traditions and culture to the resettled generations. But even on Gardi Sugdub, younger generations seem less inclined to practice the traditional customs — like making and wearing wini (vibrantly colored beads worn around the arms and legs) and molas (intricately designed fabric dresses that have become a symbol of Guna life and resistance to colonialism). Murphy began learning the craft when she was 6 years old. She spends two months constructing each ensemble, which she sells to tourists for $80.

    Oliver-Smith is optimistic about the relocation plan but worries that the Panamanian government has repeated some mistakes that have doomed projects elsewhere by treating resettlement solely as a housing issue. “You don’t just pick people up and move them from point A to point B. It is a reconfiguring of a life of a people,” Oliver-Smith says. “It has political, social, economic, environmental, spiritual and cultural dimensions.”

    As is often the case when Indigenous and rural communities relocate, Arenas says, the government failed to make the Guna equal participants in the design concept. “The Panamanian government is trying to build a Panama City neighborhood in the middle of a tropical forest,” he says. “They have not tried to save a single tree of this beautiful landscape…. They removed everything. They tried to flatten the land because it’s cheaper…. It’s also extremely hot there, and the building materials are hot.” This increases the risk of failure, he says, because the houses don’t match the environment.

    But Murphy hopes everything will be better. The new village promises dry land and more space. And perhaps returning to the mainland the Guna occupied nearly 150 years ago will lead to a stronger connection to Guna historical culture and traditions.

    Oliver-Smith says the Guna are facing the challenge of resettlement with an intact culture and language that he hopes will be a basis for maintaining cultural continuity. His time spent with the Guna has convinced him that, as disruptive and devastating as resettlement can be, the Guna relocating as a cohesive group are perhaps best equipped to emerge intact even if not unscathed.

    “Carlos [Arenas] and I asked an old, retired saila if he thought resettlement would change the Guna,” he says. “He said, ‘No. Individuals may change out of choice, but our culture is eternal. It will never die.’ ” More

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    Internet access must become human right or we risk ever-widening inequality

    People around the globe are so dependent on the internet to exercise socio-economic human rights such as education, healthcare, work, and housing that online access must now be considered a basic human right, a new study reveals.
    Particularly in developing countries, internet access can make the difference between people receiving an education, staying healthy, finding a home, and securing employment — or not.
    Even if people have offline opportunities, such as accessing social security schemes or finding housing, they are at a comparative disadvantage to those with Internet access.
    Publishing his findings today in Politics, Philosophy & Economics, Dr Merten Reglitz, Lecturer in Global Ethics at the University of Birmingham, calls for a standalone human right to internet access — based on it being a practical necessity for a range of socio-economic human rights.
    He calls for public authorities to provide internet access free of charge for those unable to afford it, as well as providing training in basic digital skills training for all citizens and protecting online access from arbitrary interference by states and private companies.
    Dr Reglitz commented: “The internet has unique and fundamental value for the realisation of many of our socio-economic human rights — allowing users to submit job applications, send medical information to healthcare professionals, manage their finances and business, make social security claims, and submit educational assessments.
    “The internet’s structure enables a mutual exchange of information that has the potential to contribute to the progress of humankind as a whole — potential that should be protected and deployed by declaring access to the Internet a human right.”
    The study outlines several areas in developed countries where internet access is essential to exercise socio-economic human rights: Education — students in internet-free households are disadvantaged in obtaining a good school education with essential learning aids and study materials online. Health — providing in-person healthcare to remote communities can be challenging, particularly in the US and Canada. Online healthcare can help to plug this gap. Housing — in many developed countries, significant parts of the rental housing market have moved online. Social Security — accessing these public services today is often unreasonably difficult without internet access. Work — jobs are increasingly advertised in real time online and people must be able to access relevant websites to make effective use of their right to work.Dr Reglitz’s research also highlights similar problems for people without internet access in developing countries — for example, 20 per cent of children aged 6 to 11 are out of school in sub-Saharan Africa. Many children face long walks to their schools, where class sizes are routinely very large in crumbling, unsanitary schools with insufficient numbers of teachers.
    However, online education tools can make a significant difference — allowing children living remotely from schools to complete their education. More students can be taught more effectively if teaching materials are available digitally and pupils do not have to share books.
    For people in developing countries, internet access can also make the difference between receiving an adequate level of healthcare or receiving none. Digital health tools can help diagnose illnesses — for example, in Kenya, a smartphone-based Portable Eye Examination Kit (Peek) has been used to test people’s eyesight and identify people who need treatment, especially in remote areas underserved by medical practitioners.
    People are often confronted with a lack of brick-and-mortar banks in developing countries and internet access makes possible financial inclusion. Small businesses can also raise money through online crowdfunding platforms — the World Bank expects such sums raised in Africa to rise from $32 million in 2015 to $2.5 billion in 2025. More

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    Baseball’s home run boom is due, in part, to climate change

    Baseball is the best sport in the world for numberphiles. There are so many stats collected that the analysis of them even has its own name: sabermetrics. Like in Moneyball, team managers, coaches and players use these statistics in game strategy, but the mountain of available data can also be put to other uses.

    Researchers have now mined baseball’s number hoard to show that climate change caused more than 500 home runs since 2010, with higher air temperatures contributing to the sport’s ongoing home run heyday. The results appear April 7 in the Bulletin of the American Meteorological Society.

    Many factors have led to players hitting it out of the park more often in the last 40 years, from steroid use to the height of the stitches on the ball. Blog posts and news stories have also speculated about whether climate change could be increasing the number of home runs, says Christopher Callahan of Dartmouth College (SN: 3/10/22). “But nobody had quantitatively investigated it.”

    A climate change researcher and baseball fan, Callahan decided to dig into the sport’s mound of data in his free time to answer the question. After he gave a brief presentation at Dartmouth on the topic, two researchers from different fields joined the project.

    That collaboration produced an analysis that is methodologically sound and “does what it says,” says Madeleine Orr, a researcher of the impacts of climate change on sports at Loughborough University London, who was not involved with the study.

    The theorized relationship between global warming and home runs stems from fundamental physics — the ideal gas law says as temperature goes up, air density goes down, reducing air resistance. To see if home runs were happening due to warming, Callahan and colleagues took several approaches.

    First, the team looked for an effect at the game level. Across more than 100,000 MLB games, the researchers found that a 1-degree Celsius increase in the daily high temperature increased the number of home runs in a game by nearly 2 percent. For example, a game like the one on June 10, 2019, where the Arizona Diamondbacks and Philadelphia Phillies set the record for most home runs in a game, would be expected to have 14 home runs instead of 13 if it were 4 degrees C warmer.

    The researchers then ran game-day temperatures through a climate model that controls for greenhouse gas emissions and found that human-caused warming led to an average of 58 more home runs each season from 2010 to 2019. The analysis also showed that the overall trend of more home runs in higher temperatures goes back to the 1960s.

    The team followed that analysis with a look at more than 220,000 individual batted balls, made possible by the Statcast system — where high-speed cameras have tracked the trajectory and speed of every ball hit during a game since 2015. The researchers compared balls hit in almost exactly the same way on days with different temperatures, while controlling for other factors like wind speed and humidity. That analysis showed a similar increase in home runs per degree Celsius as the game-level analysis, with only lower air density due to higher temperatures left to explain higher numbers of home runs.

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    While climate change has “not been the dominant effect” causing more home runs, “if we continue to emit greenhouse gases strongly, we could see much more rapid increases in home runs” moving forward, Callahan says.

    Some fans feel that the prevalence of home runs has made baseball duller, and it’s at least part of the reason that the MLB unveiled several new rule changes for the 2023 season, Callahan says.

    Teams can adapt to rising temperatures by shifting day games to night games and adding domes to stadiums — the researchers found no effect of temperature on home runs for games played under a dome. But according to Orr, climate change may soon cause even more dramatic changes to America’s pastime, even with those adaptations.

    Because the sport is susceptible to snow, storms, wildfires, flooding and heat at various points during the season, Orr says, “I don’t think, without substantial change, baseball exists in the current model” within 30 years.

    Callahan agrees. “This sport, and all sports, are going to see major changes in ways that we cannot anticipate.” More

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    ‘Jet packs’ and ultrasounds could reveal secrets of pregnant whale sharks

    How do you know if the world’s largest living fish is expecting babies? Not by her bulging belly, it turns out.

    Scientists thought that an enlarged area on the undersides of female whale sharks was a sign of pregnancy. But a technique used for the first time on free-swimming animals showed only skin and muscle. These humps might instead be a secondary sex characteristic on mature females, like breasts on humans, researchers report in the March 23 Endangered Species Research.

    The ultrasound is part of a suite of new methods including underwater “jet packs” and blood tests that scientists hope could unlock secrets about this creature’s reproduction.

    Whale sharks (Rhincodon typus) are classified as globally endangered by the International Union for Conservation of Nature. There are only an estimated 100,000 to 238,000 individuals left worldwide, which is more than a 50 percent decline in the last 75 years.

    In part because whale sharks are relatively rare, their reproductive biology is mostly a mystery (SN: 8/1/22). Nearly everything biologists think they know is based on the examination of one pregnant female caught by a commercial fishing boat in 1995.

    “Protecting organisms without knowing about their biology is like trying to catch a fly with our eyes closed,” says Rui Matsumoto, a fisheries biologist with the Okinawa Churashima Foundation in Japan. The organization researches subtropical animals and plants to maintain or improve natural resources in national parks.

    To learn more about these gentle giants, Matsumoto and shark biologist Kiyomi Murakumo of Japan’s Okinawa Churaumi Aquarium had to figure out how to keep up with them. Like superheroes in a comic book, the biologists used underwater jet packs — propellers attached to their scuba tanks — to swim alongside the fish, which average 12 meters in length and move about five kilometers per hour.

    Then the researchers had to maneuver a 17-kilogram briefcase containing a waterproof ultrasound wand on the undersides of 22 females swimming near the Galápagos Islands and draw blood with syringes from their fins. Until this study, the ultrasound wand had never been used outside of an aquarium on free-swimming wildlife.

    Fisheries biologist Rui Matsumoto uses a propeller mounted on his scuba tank to keep pace with a female whale shark to take an ultrasound of her belly.S. Pierce

    Performing these two tests on whale sharks is especially challenging, says study coauthor Simon Pierce, a whale shark ecologist with the Marine Megafauna Foundation, a nonprofit organization that uses research to drive marine conservation.  The fish “have some of the thickest skin of any animal — up to about 30 centimeters thick.”

    Another challenge is the seawater itself, which can contaminate blood samples. The researchers developed a two-syringe system, where the first syringe creates a vacuum and allows the second syringe to draw only blood. 

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    Back in the lab, the blood plasma from six of the females showed hormone levels similar to levels obtained from a captive immature female in an aquarium, indicating those wild females were not old enough to reproduce.

    Ultrasound imagery showed egg follicles in two of the 22 female sharks, meaning those females were mature enough to reproduce but not pregnant. The biologists did not locate a pregnant whale shark.

    Pioneering these noninvasive techniques on whale sharks has opened the door to possibly learning more about other endangered marine animals, too. Waterproof ultrasound wands mounted on a pole, Pierce says, are now being used on tiger sharks in places where the predators are drawn in by bait.

    Rachel Graham agrees developing these underwater sampling techniques is an “astounding feat.” But the marine conservation scientist and founder of MarAlliance, a marine wildlife conservation nonprofit, doubts whether most free-ranging wild marine animals, particularly faster-swimming sharks or marine mammals, would tolerate similar tests.

    “What makes whale sharks fairly unique … is that they move relatively slowly at times, have the ability to remain stationary, and they tolerate the presence of other animals — such as us — nearby,” says Graham, who has studied shark species around the world and was not involved in the new study.

    Coupled with satellite tracking, the new methods, could eventually show us where whale sharks give birth, Pierce says. Little is known about whale shark pups, including whether they are born in shallow or deep water, and whether pups are born one-at-a-time or if mothers gather to give birth together. “Assuming they do have some sort of breeding or pelagic nursery area we can identify … then that obviously goes quite a long way towards conserving the population.” More

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    New atomic-scale understanding of catalysis could unlock massive energy savings

    In an advance they consider a breakthrough in computational chemistry research, University of Wisconsin-Madison chemical engineers have developed a model of how catalytic reactions work at the atomic scale. This understanding could allow engineers and chemists to develop more efficient catalysts and tune industrial processes — potentially with enormous energy savings, given that 90% of the products we encounter in our lives are produced, at least partially, via catalysis.
    Catalyst materials accelerate chemical reactions without undergoing changes themselves. They are critical for refining petroleum products and for manufacturing pharmaceuticals, plastics, food additives, fertilizers, green fuels, industrial chemicals and much more.
    Scientists and engineers have spent decades fine-tuning catalytic reactions — yet because it’s currently impossible to directly observe those reactions at the extreme temperatures and pressures often involved in industrial-scale catalysis, they haven’t known exactly what is taking place on the nano and atomic scales. This new research helps unravel that mystery with potentially major ramifications for industry.
    In fact, just three catalytic reactions — steam-methane reforming to produce hydrogen, ammonia synthesis to produce fertilizer, and methanol synthesis — use close to 10% of the world’s energy.
    “If you decrease the temperatures at which you have to run these reactions by only a few degrees, there will be an enormous decrease in the energy demand that we face as humanity today,” says Manos Mavrikakis, a professor of chemical and biological engineering at UW-Madison who led the research. “By decreasing the energy needs to run all these processes, you are also decreasing their environmental footprint.”
    Mavrikakis and postdoctoral researchers Lang Xu and Konstantinos G. Papanikolaou along with graduate student Lisa Je published news of their advance in the April 7, 2023 issue of the journal Science.

    In their research, the UW-Madison engineers develop and use powerful modeling techniques to simulate catalytic reactions at the atomic scale. For this study, they looked at reactions involving transition metal catalysts in nanoparticle form, which include elements like platinum, palladium, rhodium, copper, nickel, and others important in industry and green energy.
    According to the current rigid-surface model of catalysis, the tightly packed atoms of transition metal catalysts provide a 2D surface that chemical reactants adhere to and participate in reactions. When enough pressure and heat or electricity is applied, the bonds between atoms in the chemical reactants break, allowing the fragments to recombine into new chemical products.
    “The prevailing assumption is that these metal atoms are strongly bonded to each other and simply provide ‘landing spots’ for reactants. What everybody has assumed is that metal-metal bonds remain intact during the reactions they catalyze,” says Mavrikakis. “So here, for the first time, we asked the question, ‘Could the energy to break bonds in reactants be of similar amounts to the energy needed to disrupt bonds within the catalyst?'”
    According to Mavrikakis’s modeling, the answer is yes. The energy provided for many catalytic processes to take place is enough to break bonds and allow single metal atoms (known as adatoms) to pop loose and start traveling on the surface of the catalyst. These adatoms combine into clusters, which serve as sites on the catalyst where chemical reactions can take place much easier than the original rigid surface of the catalyst.
    Using a set of special calculations, the team looked at industrially important interactions of eight transition metal catalysts and 18 reactants, identifying energy levels and temperatures likely to form such small metal clusters, as well as the number of atoms in each cluster, which can also dramatically affect reaction rates.

    Their experimental collaborators at the University of California, Berkeley, used atomically-resolved scanning tunneling microscopy to look at carbon monoxide adsorption on nickel (111), a stable, crystalline form of nickel useful in catalysis. Their experiments confirmed models that showed various defects in the structure of the catalyst can also influence how single metal atoms pop loose, as well as how reaction sites form.
    Mavrikakis says the new framework is challenging the foundation of how researchers understand catalysis and how it takes place. It may apply to other non-metal catalysts as well, which he will investigate in future work. It is also relevant to understanding other important phenomena, including corrosion and tribology, or the interaction of surfaces in motion.
    “We’re revisiting some very well-established assumptions in understanding how catalysts work and, more generally, how molecules interact with solids,” Mavrikakis says.
    Manos Mavrikakis is Ernest Micek Distinguished Chair, James A. Dumesic Professor, and Vilas Distinguished Achievement Professor in Chemical and Biological Engineering at the University of Wisconsin-Madison.
    Other authors include Barbara A.J. Lechner of the Technical University of Munich, and Gabor A. Somorjai and Miquel Salmeron of Lawrence Berkeley National Laboratory and the University of California, Berkeley.
    The authors acknowledge support from the U.S. Department of Energy, Basic Energy Sciences, Division of Chemical Sciences, Catalysis Science Program, Grant DE-FG02-05ER15731; the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, of the U.S. Department of Energy under contract no. DE-AC02-05CH11231, through the Structure and Dynamics of Materials Interfaces program (FWP KC31SM).
    Mavrikakis acknowledges financial support from the Miller Institute at UC Berkeley through a Visiting Miller Professorship with the Department of Chemistry.
    The team also used the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC award BES- ERCAP0022773.
    Part of the computational work was carried out using supercomputing resources at the Center for Nanoscale Materials, a DOE Office of Science User Facility located at Argonne National Laboratory, supported by DOE contract DE-AC02-06CH11357. More

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    Fully recyclable printed electronics ditch toxic chemicals for water

    Engineers at Duke University have produced the world’s first fully recyclable printed electronics that replace the use of chemicals with water in the fabrication process. By bypassing the need for hazardous chemicals, the demonstration points down a path industry could follow to reduce its environmental footprint and human health risks.
    The research appeared online Feb. 28 in the journal Nano Letters.
    One of the dominant challenges facing any electronics manufacturer is successfully securing several layers of components on top of each other, which is crucial to making complex devices. Getting these layers to stick together can be a frustrating process, particularly for printed electronics.
    “If you’re making a peanut butter and jelly sandwich, one layer on either slice of bread is easy,” explained Aaron Franklin, the Addy Professor of Electrical and Computer Engineering at Duke, who led the study. “But if you put the jelly down first and then try to spread peanut butter on top of it, forget it, the jelly won’t stay put and will intermix with the peanut butter. Putting layers on top of each other is not as easy as putting them down on their own — but that’s what you have to do if you want to build electronic devices with printing.”
    In previous work, Franklin and his group demonstrated the first fully recyclable printed electronics. The devices used three carbon-based inks: semiconducting carbon nanotubes, conductive graphene and insulating nanocellulose. In trying to adapt the original process to only use water, the carbon nanotubes presented the largest challenge.
    To make a water-based ink in which the carbon nanotubes don’t clump together and spread evenly on a surface, a surfactant similar to detergent is added. The resulting ink, however, does not create a layer of carbon nanotubes dense enough for a high current of electrons to travel across.

    “You want the carbon nanotubes to look like al dente spaghetti strewn down on a flat surface,” said Franklin. “But with a water-based ink, they look more like they’ve been taken one-by-one and tossed on a wall to check for doneness. If we were using chemicals, we could just print multiple passes again and again until there were enough nanotubes. But water doesn’t work that way. We could do it 100 times and there’d still be the same density as the first time.”
    This is because the surfactant used to keep the carbon nanotubes from clumping also prevents additional layers from adhering to the first. In a traditional manufacturing process, these surfactants would be removed using either very high temperatures, which takes a lot of energy, or harsh chemicals, which can pose human and environmental health risks. Franklin and his group wanted to avoid both.
    In the paper, Franklin and his group develop a cyclical process in which the device is rinsed with water, dried in relatively low heat and printed on again. When the amount of surfactant used in the ink is also tuned down, the researchers show that their inks and processes can create fully functional, fully recyclable, fully water-based transistors.
    Compared to a resistor or capacitor, a transistor is a relatively complex computer component used in devices such as power control or logic circuits and sensors. Franklin explains that, by demonstrating a transistor first, he hopes to signal to the rest of the field that there is a viable path toward making some electronics manufacturing processes much more environmentally friendly.
    Franklin has already proven that nearly 100% of the carbon nanotubes and graphene used in printing can be recovered and reused in the same process, losing very little of the substances or their performance viability. Because nanocellulose is made from wood, it can simply be recycled or biodegraded like paper. And while the process does use a lot of water, it’s not nearly as much as what is required to deal with the toxic chemicals used in traditional fabrication methods.
    According to a United Nations estimate, less than a quarter of the millions of pounds of electronics thrown away each year is recycled. And the problem is only going to get worse as the world eventually upgrades to 6G devices and the Internet of Things (IoT) continues to expand. So any dent that could be made in this growing mountain of electronic trash is important to pursue.
    While more work needs to be done, Franklin says the approach could be used in the manufacturing of other electronic components like the screens and displays that are now ubiquitous to society. Every electronic display has a backplane of thin-film transistors similar to what is demonstrated in the paper. The current fabrication technology is high-energy and relies on hazardous chemicals as well as toxic gasses. The entire industry has been flagged for immediate attention by the US Environmental Protection Agency. [https://www.epa.gov/climateleadership/sector-spotlight-electronics]
    “The performance of our thin-film transistors doesn’t match the best currently being manufactured, but they’re competitive enough to show the research community that we should all be doing more work to make these processes more environmentally friendly,” Franklin said.
    This work was supported by the National Institutes of Health (1R01HL146849), the Air Force Office of Scientific Research (FA9550-22-1-0466), and the National Science Foundation (ECCS-1542015, Graduate Research Fellowship 2139754). More

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    in Computers Math

    AI-equipped eyeglasses read silent speech

    Cornell University researchers have developed a silent-speech recognition interface that uses acoustic-sensing and artificial intelligence to continuously recognize up to 31 unvocalized commands, based on lip and mouth movements.
    The low-power, wearable interface — called EchoSpeech — requires just a few minutes of user training data before it will recognize commands and can be run on a smartphone.
    Ruidong Zhang, doctoral student of information science, is the lead author of “EchoSpeech: Continuous Silent Speech Recognition on Minimally-obtrusive Eyewear Powered by Acoustic Sensing,” which will be presented at the Association for Computing Machinery Conference on Human Factors in Computing Systems (CHI) this month in Hamburg, Germany.
    “For people who cannot vocalize sound, this silent speech technology could be an excellent input for a voice synthesizer. It could give patients their voices back,” Zhang said of the technology’s potential use with further development.
    In its present form, EchoSpeech could be used to communicate with others via smartphone in places where speech is inconvenient or inappropriate, like a noisy restaurant or quiet library. The silent speech interface can also be paired with a stylus and used with design software like CAD, all but eliminating the need for a keyboard and a mouse.
    Outfitted with a pair of microphones and speakers smaller than pencil erasers, the EchoSpeech glasses become a wearable AI-powered sonar system, sending and receiving soundwaves across the face and sensing mouth movements. A deep learning algorithm then analyzes these echo profiles in real time, with about 95% accuracy.
    “We’re moving sonar onto the body,” said Cheng Zhang, assistant professor of information science and director of Cornell’s Smart Computer Interfaces for Future Interactions (SciFi) Lab.
    “We’re very excited about this system,” he said, “because it really pushes the field forward on performance and privacy. It’s small, low-power and privacy-sensitive, which are all important features for deploying new, wearable technologies in the real world.”
    Most technology in silent-speech recognition is limited to a select set of predetermined commands and requires the user to face or wear a camera, which is neither practical nor feasible, Cheng Zhang said. There also are major privacy concerns involving wearable cameras — for both the user and those with whom the user interacts, he said.
    Acoustic-sensing technology like EchoSpeech removes the need for wearable video cameras. And because audio data is much smaller than image or video data, it requires less bandwidth to process and can be relayed to a smartphone via Bluetooth in real time, said François Guimbretière, professor in information science.
    “And because the data is processed locally on your smartphone instead of uploaded to the cloud,” he said, “privacy-sensitive information never leaves your control.” More

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    in Computers Math

    Technology advance paves way to more realistic 3D holograms for virtual reality and more

    Researchers have developed a new way to create dynamic ultrahigh-density 3D holographic projections. By packing more details into a 3D image, this type of hologram could enable realistic representations of the world around us for use in virtual reality and other applications.
    “A 3D hologram can present real 3D scenes with continuous and fine features,” said Lei Gong, who led a research team from the University of Science and Technology of China. “For virtual reality, our method could be used with headset-based holographic displays to greatly improve the viewing angles, which would enhance the 3D viewing experience. It could also provide better 3D visuals without requiring a headset.”
    Producing a realistic-looking holographic display of 3D objects requires projecting images with a high pixel resolution onto a large number of successive planes, or layers, that are spaced closely together. This achieves high depth resolution, which is important for providing the depth cues that make the hologram look three dimensional.
    In Optica, Optica Publishing Group’s journal for high-impact research, Gong’s team and Chengwei Qiu’s research team at the National University of Singapore describe their new approach, called three-dimensional scattering-assisted dynamic holography (3D-SDH). They show that it can achieve a depth resolution more than three orders of magnitude greater than state-of-the-art methods for multiplane holographic projection.
    “Our new method overcomes two long-existing bottlenecks in current digital holographic techniques — low axial resolution and high interplane crosstalk — that prevent fine depth control of the hologram and thus limit the quality of the 3D display,” said Gong. “Our approach could also improve holography-based optical encryption by allowing more data to be encrypted in the hologram.”
    Producing more detailed holograms
    Creating a dynamic holographic projection typically involves using a spatial light modulator (SLM) to modulate the intensity and/or phase of a light beam. However, today’s holograms are limited in terms of quality because current SLM technology allows only a few low-resolution images to be projected onto sperate planes with low depth resolution.
    To overcome this problem, the researchers combined an SLM with a diffuser that enables multiple image planes to be separated by a much smaller amount without being constrained by the properties of the SLM. By also suppressing crosstalk between the planes and exploiting scattering of light and wavefront shaping, this setup enables ultrahigh-density 3D holographic projection.
    To test the new method, the researchers first used simulations to show that it could produce 3D reconstructions with a much smaller depth interval between each plane. For example, they were able to project a 3D rocket model with 125 successive image planes at a depth interval of 0.96 mm in a single 1000×1000-pixel hologram, compared to 32 image planes with a depth interval of 3.75 mm using another recently developed approach known as random vector-based computer-generated holography.
    To validate the concept experimentally, they built a prototype 3D-SDH projector to create dynamic 3D projections and compared this to a conventional state-of- the-art setup for 3D Fresnel computer-generated holography. They showed that 3D-SDH achieved an improvement in axial resolution of more than three orders of magnitude over the conventional counterpart.
    The 3D holograms the researchers demonstrated are all point-cloud 3D images, meaning they cannot present the solid body of a 3D object. Ultimately, the researchers would like to be able to project a collection of 3D objects with a hologram, which would require a higher pixel-count hologram and new algorithms. More