Breakthroughs and trends in the world of technology
Fluid Dynamics
Flash in the Pan
Back in 1751, German physician Johann Leidenfrost discovered that a drop of water placed on a 150ºC surface levitates instead of boiling away. The phenomenon that bears his name occurs because the steam produced at the leading edge of the droplet forms a gaseous cushion that keeps the water suspended. Five years ago, a Virginia Tech undergraduate student decided to see if the Leidenfrost effect also worked with ice. It did not—at least not at 150ºC. The meltwater continued to boil on contact with the surface, until the temperature was hiked to 550ºC. Now associate professor of mechanical engineering Jonathan Boreyko and graduate student Mojtaba Edalatpour—shown here putting ice on a hot plate in Virginia Tech’s Nature-Inspired Fluids and Interfaces Lab—have discovered why. It turns out that the meltwater beneath the ice is layered into two different bands of extreme temperatures. The bottom half boils, which fixes its temperature at 100ºC, but the top layer remains adhered to the ice, which keeps its temperature at 0ºC. The finding that ice flashes to steam more easily than water could open the door to new heat-transfer applications, such as cooling metal alloys more quickly to make them stronger or combating fires. Boreyko says firehoses could be made more effective if they sprayed ice chips instead of water. – Thomas K. Grose
© Alex Parrish/Virginia Tech
Energy Efficiency
Pane Gains
Heating and cooling consume a fifth of all energy used in the United States and other industrialized countries, so developers are constantly looking for ways to make homes and commercial buildings more sustainable. For example, smart windows currently on the market can be electronically triggered to darken on bright days and block visible and near-infrared rays. That obscures the view, however. According to Chemical and Engineering News, a team led by Nathan Youngblood, an assistant professor of electrical and computer engineering at the University of Pittsburgh, and Harish Bhaskaran, a professor of applied nanomaterials at the University of Oxford, has devised a window coating that absorbs the sun’s near-infrared rays in cold weather and reflects them when it’s warm—while keeping the glass transparent. The researchers say their switchable glaze could cut a home’s energy use by 25 percent compared with energy-efficient windows now sold. The ultrathin coating’s key ingredient is a phase-change material that can switch between crystalline and amorphous states when heated to between 280ºC and 450ºC. The team now is working to lower those temperatures to commercially viable thresholds. – T. G.
© Getty Images
Greenhouse Gases
Flatulent Earth
Last year, a European Space Agency satellite spotted a methane leak at a Madrid landfill. Over several months, two Canadian satellites, Iris and Hugo, not only confirmed and mapped the leak but also discovered another at a neighboring site. According to Smithsonian magazine, emissions from areas totaled some 19,000 pounds of methane per hour. Though it doesn’t remain in the atmosphere as long as carbon dioxide, methane can have around 80 times the atmospheric warming effect and accounts for 30 percent of global warming. Methane leaks from landfills, refineries, pipelines, and mines were previously hard to detect and usually required expensive aerial overflights or ground monitors. Now, the article explains, satellites are better and cheaper at finding methane emissions. That helped lead to last year’s Global Methane Pledge at the 26th annual United Nations climate change summit (COP26) in Glasgow, Scotland, where more than 100 countries promised to chop methane emissions by 30 percent from 2020 levels by 2030. Plugging methane leaks offers a quicker, easier route to realizing that goal, with measurable short-term benefits. – T. G.
© Getty Images
Neuroscience
Quick Studies
Pong, a pioneering videogame released by Atari in 1972, involved moving a cursor as if it were a ping-pong paddle to smack a digital “ball” toward another paddle wielded by the computer on the opposite side of the screen. It was easy to learn and fun to play. How easy? A group of Australian and British researchers has taught a cluster of human brain cells to play, according to the online news outlet Medical Xpress. The researchers put human stem cells on a microelectric array, then grew them into brain cells in a configuration that enables the cells to both stimulate and read the activity of the others. Electrical signals tell the cluster where the ball is located, while the distance of the signal provides information regarding frequency. The clump of cells was taught to play the same way humans learn: by playing repeatedly and gaining insights from successes and failures. Feedback came from electrical signals in the electrodes. The cells learned to play in just five minutes—much faster than it took artificial-intelligence machines. Still, the overall skill level of the brain cells was vastly inferior to that of humans and AI. (Whew!) The team says the Pong-playing cells could help improve the design of machine-learning systems or be useful in testing therapies that target neurons. – T. G.
© Getty Images
Biomedical Engineering
Damage Control
Pyroptosis, or cell death, is typically caused by microbial infections and triggers excess inflammation in the body. Long thought to be irreversible, the process apparently has an on/off switch and thus can be controlled, according to biomedical engineers at the University of Illinois at Chicago. Their new analysis method, which enabled them to watch the process unfold in real time, could open new treatment avenues for sepsis, acute respiratory distress syndrome, cancer, and other diseases related to cell-death malfunctions. The biochemical reactions caused by pyroptosis center on a protein called gasdermin, which opens large pores in a cell’s membrane and destabilizes it. The UIC team genetically engineered an “optogenetic” gasdermin, activated by florescent imaging technology, and then observed the pores under various circumstances. Observing pyroptosis mechanisms at work in live cells had been challenging because pathogens behave unpredictably and have disparate effects on different cells and people. By contrast, optogenetic gasdermin mimics at the molecular level what happens in a cell once pyroptosis commences, eliminating those uncertainties. The researchers discovered an automatic response to various external circumstances that can trigger the pores to shut within tens of seconds—proof that pyroptosis self-regulates. The finding opens the door to novel therapies that can control the cell killer’s “cancel button.” – T. G.
© Gary Mo, et al./University of Illinois at Chicago
Autonomous Vehicles
Spheres of Influence
Pyroptosis, or cell death, is typically caused by microbial infections and triggers excess inflammation in the body. Long thought to be irreversible, the process apparently has an on/off switch and thus can be controlled, according to biomedical engineers at the University of Illinois at Chicago. Their new analysis method, which enabled them to watch the process unfold in real time, could open new treatment avenues for sepsis, acute respiratory distress syndrome, cancer, and other diseases related to cell-death malfunctions. The biochemical reactions caused by pyroptosis center on a protein called gasdermin, which opens large pores in a cell’s membrane and destabilizes it. The UIC team genetically engineered an “optogenetic” gasdermin, activated by florescent imaging technology, and then observed the pores under various circumstances. Observing pyroptosis mechanisms at work in live cells had been challenging because pathogens behave unpredictably and have disparate effects on different cells and people. By contrast, optogenetic gasdermin mimics at the molecular level what happens in a cell once pyroptosis commences, eliminating those uncertainties. The researchers discovered an automatic response to various external circumstances that can trigger the pores to shut within tens of seconds—proof that pyroptosis self-regulates. The finding opens the door to novel therapies that can control the cell killer’s “cancel button.” – T. G.
© Phillips, et al.
Engineering Education
Lock and Keystrokes
Recidivism rates in US prisons are high and rising, but studies show that educational programs can reduce the return of former inmates by 43 percent. That inspired two MIT PhD students to cofound Brave Behind Bars, an online and in-person computer engineering course that aims to prepare incarcerated women for the workplace. The curriculum, which emphasizes practical as well as technical skills and includes a capstone project, was designed by Martin Nisser, a computer science student, and mathematics student Marisa Gaetz. Thirty women at four different New England prisons enrolled in the pilot program in 2020. Students learn the fundamentals of web programming and digital literacy; for their capstone project, each picks an issue that she’s passionate about and builds a website that addresses it. Many women construct websites that grapple with domestic violence, an issue with which many are all too familiar. The program has had to overcome logistical hurdles, including coordinating class times across four facilities, security constraints, a lack of WiFi access for some of the women, and varying access to laptops. Moreover, much of the subject matter is completely new to the students, so their learning curve is steep. Still, they display “an equally big appetite” to master the material, says Nisser, adding that “these women are some of the most engaged students I’ve worked with.” – T. G.
© Getty Images
Biomimicry
Manual Dexterity
A human hand can easily glide between power and precision grasps. Robotic hands prove far less versatile. A team of mechanical engineering researchers at Stanford University may be on the verge of changing that dynamic. Their robotic gripper, farmHand, can grab heavy jugs of liquid and pluck grapes with equal aplomb, thanks to an adhesive inspired by the toes of the gecko, an agile lizard renowned for clinging to slick vertical surfaces. Like gecko digits, the adhesive can grip but isn’t sticky and leaves no residue. The lizard owes its amazing grip to microscopic flaps that create an intermolecular force when in full contact with a surface—the result of a slight shift in the electrons surrounding the molecules. That shift allows the gecko’s toes to strongly grip an item with little force. By mimicking those flaps in their adhesive, the researchers could easily control the force on a flat surface. That proved harder to achieve when the adhesive pads on each of the robot’s four fingers contacted an object at different angles. The solution: position a layer of collapsible rib structures beneath each pad that buckles at the slightest touch. The addition ensures equal pressure is applied, regardless of angle. – T. G.
© Science Robotics
Biomaterials
Bone Spurs
Materials scientists at the universities of Linköping (Sweden) and Okayama (Japan) have developed a gel that could one day help repair complex fractures. Based on a biomolecule developed by the Japanese researchers that can quickly stimulate bone growth, the gel can be coaxed into various shapes before hardening. Its material, called alginate, is covered on one side by an electroactive polymer that can change its volume and bend when a low voltage is applied. The other side contains the biomolecules, which are extracted from the membrane of cells involved in bone development. When the biomolecules are placed in a cell culture medium similar to a body’s interior environment, the gel mineralizes and hardens like bone. Engraving patterns in the gel determines what shape it will morph into once the voltage is applied. The researchers demonstrated that the gel can wrap itself around chicken bones, and the artificial bone that subsequently develops grows in tandem with those bones. Ideally, the gel could be used to create microrobots injected into the body. – T. G.
© Getty Images
Climate Change
Greenhouse Gas Trap
Carbon capture and sequestration (CCS) technologies grab carbon dioxide from smokestacks and compress it into a liquid for injection underground. Because they’re costly and require a lot of energy to work, the technologies have not seen widespread use. Now researchers at Australia’s Royal Melbourne Institute of Technology have developed an inexpensive method that instantaneously and permanently converts captured CO₂ into a solid—a material that won’t leak, is easier to bury, and may have commercial applications. The researchers say their CCS process is aimed at heavy industries, particularly cement and steel manufacturers, which belch huge amounts of CO₂ into the air during production. The RMIT technology, which can be easily integrated into existing manufacturing processes, starts with heating liquid metal to between 100ºC and 120ºC. CO₂ injected into the liquid metal bubbles up, and the gas moving through the metal forms into flakes of solid carbon—a reaction that takes just a split second. Those temperatures are low enough for the process to be powered by renewable energy. Now that the researchers have a proof of concept, they plan to build a larger prototype the size of a shipping container. They’re also investigating possible uses for solid carbon, including construction materials. If the CCS technology ultimately yields value-added products, it could be green in more ways than one. – T. G.
© Getty Images
Space Exploration
Star Struck
Ready for 2024: A Space Odyssey? That’s when British company Space Entertainment Enterprise (SEE) plans to connect a media-production studio to the International Space Station. The firm has commissioned Axiom Space of Houston to build the inflatable module, Space.com reports. It will allow artists to produce, record, and livestream content including films, TV, music, and sports events in a low-orbit, microgravity environment. The studio will be attached to a commercial section called Axiom Station that the firm, whose CEO served as NASA’s ISS program manager, is constructing. After four years, Axiom hopes to detach its station and turn it into a separate orbiting platform. SEE also is coproducing Tom Cruise’s space movie, for which the actor is teaming up with NASA and SpaceX. If successful, it would be the second feature-length film shot on the ISS. Last year, a Russian film crew spent 12 days there making The Challenge, about a doctor sent aloft to treat an ailing cosmonaut. Meanwhile, Smithsonian magazine reports on a first-ever archeological “dig” into life aboard the ISS. Researchers at Chapman University and Australia’s Flinders University hope that studying how astronauts relate and adapt to their physical environment will help future designers better attune space habitats to human needs. – T. G.
© Getty Images
Gamification
Speedier Readers
Videogames, long considered detrimental to children’s literacy, may have the opposite effect, according to researchers at the Universities of Geneva and Trento—at least when the language is Italian. Reading, the investigators note, not only makes use of sound but also other skills, including vision, attention, and working memory. To test the impact, they developed a videogame that combines an action-game concept with minigames that train those sensory and cognitive functions. Set in an alternative world, the game features a child and a flying creature named Raku who are given missions to save planets. No reading is required of players. The researchers first divided 150 Italian students, ages 8 to 12, into two groups and tested their reading and attention skills. One group then played the game designed by the researchers while the other played one that teaches coding. After playing two hours per week for six weeks, the children who played the experimental game showed a sevenfold improvement in attention control compared with the control group, and the researchers observed a clear improvement in reading skills, including speed and accuracy. The students were still outperforming the control group six, twelve, and eighteen months later, tests showed. Italian is a transparent language in which each letter in a word is pronounced. The researchers next aim to determine if their game helps improve literacy in French and English. – T. G.
© Getty Images
Regenerative Medicine
Cell Shock
Osteoarthritis of the knee is the nation’s most common joint ailment, affecting some 13 percent of US women and 10 percent of men over age 60. The painful condition arises when cartilage, the spongy cushion at the ends of bones, wears down. Research has shown that a low electric current applied to the remaining cartilage can encourage cells to multiply and regenerate tissue. But where will the power come from? Implanting tiny batteries doesn’t seem like a good solution. New Scientist reports that researchers led by Thanh Nguyen, an assistant professor of mechanical engineering at the University of Connecticut, have developed a biodegradable, half millimeter-thick membrane that’s piezoelectric—meaning it generates electricity when stretched and compressed. The membrane is fashioned into a scaffold that encourages cells to grow on it. As a proof of concept, Nguyen’s team punctured the knee cartilage of rabbits, then used the material to fix the holes. After resting for a month, the rabbits were allowed to hop around for 20 minutes a day to exercise their legs and generate electricity. When the team later took tissue samples from the test bunnies, they found that cartilage cells had indeed moved into the patches and their joints appeared more intact. On a scale of 1 to 18, the rabbits in the study scored 15, on average, while those patched with a material that didn’t generate a current scored around 5. Next, the researchers want to test the membrane on larger animals, then see if the regrown cartilage lasts for a couple of years before stepping up to human trials. – T. G.
© University of Connecticut