Breakthroughs and trends in the world of technology
Many coastal communities are investing in seawalls to protect residents and property from storm surges—an increasing threat as sea levels rise. Seawalls, however, are unsightly. So a team of civil and environmental engineers at Princeton University is investigating the possibility of instead using what they call concrete umbrellas to hold back the sea—an attractive addition that would provide shade for pedestrians most days, but with a roof that can swivel toward the ocean, as a barrier against an incoming storm. The design uses a hyperbolic paraboloid (“hypar”) shape that looks like a saddle, curving inward along one axis and outward along the other. Spanish architect Felix Candela put the design to use in hundreds of buildings in Mexico in the 1950s and ’60s. The umbrellas’ thin shells would be made from reinforced concrete around 4 inches thick and would measure around 26 feet on each side. They would rest on hinges atop 10-foot-tall columns. A computational model of the design showed that the umbrellas would remain intact when hit with a wall of water 75 percent of their deployed height of 26 feet. Though the shells are thin, the hypar configuration gives the structure additional strength. The team has now built physical models that measure six inches across. The next step: Small-scale water-channel and wind-tunnel simulations that will test the models’ resistance to turbulent sea flows and powerful air currents. – Thomas K. Grose
©FotosFortheFuture/Shutterstock.com; modified by Mauricio Loyola
From the late 1940s to the early ’60s, the United States, Soviet Union, China, France, and Britain all conducted atmospheric nuclear weapons tests. The result was a doubling of carbon-14 in the atmosphere—which all living things have since absorbed, the BBC reports. Because the isotope decays at a steady rate, it can be used to judge the age of animals—the older the creature, the less carbon-14 you’ll find. Now, for the first time, scientists have used that dating technique to estimate the life span of whale sharks, the world’s largest fish, which can grow to 60 feet and weigh 22 tons. Despite their size, they’re docile and can even be a tourist attraction. But they’re also an endangered species because of overfishing. Long thought to have lengthy life spans, whale sharks have defied attempts to calculate their longevity. One failed research effort counted the distinct lines in their vertebrae to see if, like tree rings, they could reveal age. Yet carbon-14 dating did present a hurdle: getting access to samples of the spine. But a new study was able to get some from two long-dead whale sharks in Pakistan and Taiwan. The analysis reveals they likely live from 100 to 150 years. It’s hoped that the data will give scientists better guidance in determining the health of whale shark populations and make it easier to place limits on fishing. – T. G.
Head for the Trills
Neuroscientists have long scoffed at the popular belief that the right side of the brain sparks creativity, while the left drives logic and analysis. Imaging research out of Drexel University that studied how jazz musicians improvise may have settled the score. It all depends on experience. Novice musicians do, indeed, rely on their right hemisphere for improvisation. Their more experienced peers, however, are guided by their left side. The study recorded the electroencephalograms of 32 guitar players—some highly experienced, others relative newbies—as they improvised riffs to six jazz songs with programmed bass, drum, and piano accompaniments. After four experts rated the performances for creativity and other qualities, the Drexel team then compared the EEGs to determine which hemisphere was at work during the top-notch displays of improvisation. They found that if creativity is defined by quality, then the left side of the brain rules. But if it’s defined as a capability to handle novel, unfamiliar situations, then the right is in control. Expert performers rely on unconscious, automatic processes that are hard to change, but can be put at risk if the artist becomes too self-conscious and chokes. By contrast, newly trained musicians use deliberate, conscious control and thus are more open to coaching. – T. G.
What began with a stroll around the neighborhood has blossomed into an interdisciplinary, multiuniversity study that is providing engineers with new insights on creating smart materials. Moneesh Upmanyu, a professor of mechanical and industrial engineering at Northeastern University, and his son were enjoying a winter day’s walk when they noticed a rhododendron bush that looked like it was dying, according to Tech Xplore. Its leaves were curled into cigar-shaped tubes and dangling forlornly from their stems. On a subsequent foray, however, the leaves were flat, healthy-looking, and lifted toward the sun. Upmanyu, an expert in the structural properties of materials and their responses to stimuli, grew curious. His subsequent study found that water is distributed unevenly within rhododendron leaves. Freezing weather forces the top of the leaves to expand and the undersides to contract, forming a tube along the thick center spine. The shape helps the evergreen plants survive the winter by reducing the amount of unneeded sunlight they receive—radiation that would otherwise damage them—during the cold months when their metabolism shuts down. “I’m interested in how sheets change shape and how we can program smart structures,” Upmanyu told the publication. Now he can take a leaf from Mother Nature and devise materials that morph with moving water and changes in temperature. – T. G.
Bolt from the Blue
For more than 40 years, the National Oceanic and Atmospheric Administration has relied on a network of Geostationary Operational Environmental Satellites (GOES) to help forecast weather and track storms. But NOAA is halfway through a plan to assemble and launch a $10.8 billion fleet of new-generation satellites that will give it—and NASA—much greater ability to understand and forecast the increasing number of severe storms that climate change is expected to generate, according to Wired. The four, 6,000-pound satellites, built by engineers at Lockheed Martin, carry multiple instruments that can monitor such things as plumes of volcanic ash, space weather, and lightning—a bellwether for upcoming storms, the magazine notes. The first two of the satellites were launched in 2016 and 2018. Together they can monitor every single lightning strike across the Western Hemisphere, and they’ve given scientists a new understanding of the phenomenon. A bolt of lightning can materialize and then strike the ground hundreds of miles away—a much greater distance than previously known. The last two GOES birds will be launched next year and in 2024. Once aloft, the new satellites should vastly increase the ability to predict and track megastorms. – T. G.
Tip the Scales
Nearly 78 metric tons of fish are produced globally each year, according to New Scientist, and 3 percent (2.34 metric tons) of that haul is fish scales, most of which is trashed. But researchers in China have invented a process to turn piscine scales into flexible display screens for wearable electronics. Wearable devices require screens than can bend, fold, and twist, the magazine notes, so right now they’re mostly made from plastic. But that plastic can take centuries to break down in landfills, so there are ongoing efforts to find cheap, sustainable replacement materials that are biodegradable. Fish scales seem to do the trick. The team at Nanjing Tech University made an extremely thin film from gelatin extracted from the scales, then infused it with silver nanowires for electrodes and a light-emitting material composed of zinc sulfide and copper for the electronic display. It worked. And the screen, once buried in soil, biodegraded after just 24 days. It’s also recyclable, if dissolved in warm water. But, wait! There’s more: Fish-scale screens offer other advantages. Not only are they inexpensive, they have high transparency and low surface roughness. We’re hooked. – T. G.
©Nanjing Tech University/Hai-Dong
Stem Cell Research
New Life Form
“They’re neither a traditional robot nor a known species of animal. It’s a new class of artifact: a living, programmable organism.” That’s how Joshua Bongard, a professor of computer science at the University of Vermont, describes xenobots—microscopic, living robots carved from the stem cells of frogs—that he helped create with colleagues at UVM and Tufts University. The existence of xenobots was announced in a recently published paper. The cells are taken from the embryos of the African clawed frog (Xenopus laevis). Skin cells bond to form the xenobot’s overall structure; heart muscle cells pulse to give it self-propulsion. At less than a millimeter wide, xenobots are minuscule, and they can live for around a week off an internal deposit of lipids and proteins. After a clump of cells incubates, it’s cut and shaped into “body forms . . . never seen in nature” using designs churned out by a supercomputer. Though they have no brain, xenobots can do things like walk, swim, and work in groups. The researchers say that someday xenobots may be used for such things as radioactive waste removal, delivering medicines within human bodies, or removing plaque from arteries. They also say xenobots offer scientists a new means to uncover the secrets of cell biology. Some ethicists, notes the New York Times, worry about life span and potential to reproduce. But xenobots cannot reproduce or evolve, counter creators. As their website says, “It is difficult to see how an AI could create harmful organisms any easier than a talented biologist with bad intentions could.” Surprisingly, no one seems to have dubbed them Frankenbots. – T. G.
Research on soft robots is gaining traction because they’re considered safe for humans. But some designs have drawbacks. Pneumatic robots that are moved using air pumps, for example, require being hooked up to compressors or electric cords, which limit their movements. To get around this problem, a team of Stanford University mechanical engineers has come up with a soft, air-filled robot that is squishy, safe, and shape-changing but that moves like a conventional hard-bodied bot. The investigators accomplished this by figuring out a way to keep the amount of air in the robot constant at all times. Essentially, their soft bot is an inflated cloth tube that operates via three small robotic engines, which pinch it into a triangle shape. One motor squeezes the two ends together while the two others move along the tube, which can change its shape by moving its corners. To make a more complex device, two or more of the triangles can be connected to each other. The “isoperimetric robot” can shift into a variety of shapes, yet total tube length and air volume remain unchanged. The robot, which moves by rolling, can pick up an object—a ball, for instance—by enveloping it within its three sides. Sounds downright huggable. – T. G.
©Farrin Abbott/Stanford News Service
Last year, when scientists led by the Harvard-Smithsonian Center for Astrophysics released the first ever picture of a black hole, the image’s sheer beauty captivated the world. One copy is now on permanent display at New York’s Museum of Modern Art. The snapshot, the New York Times explains, was captured by the Event Horizon Telescope (EHT), a global network of eight Earth-based radio telescopes that for 10 days in 2017 focused on the black hole at the center of M87, a giant galaxy in the Virgo constellation. But the EHT team now says that the picture gives only a glimpse of the full structural complexity that a higher resolution image would offer. In a recent paper, the researchers calculated that within a black hole there is an intricate substructure of rings, due to the extreme gravitational bending of light. This light comes from the entire visible universe, and peering into the rings enables researchers to see, essentially, farther and farther back in time. As one scientist told the Times: “The image of a black hole actually contains a nested series of rings.” Michael Johnson, another of the astrophysicists, further explained in a press release that in the near-perfect images recorded so far, this series of rings is almost imperceptible to the naked eye. But adding one more telescope to the EHT would bring the rings fully into focus. In fact, the EHT collaboration plans to double the number of constituent EHT telescopes, creating a “next-generation EHT” that will push discovery to the next level, according to Space.com. In the meantime we still can marvel at the beautiful, if imperfect, vista of a fiery torus 53.5 million light years away. – T. G.
Vodka, the clear spirit that originated in Russia and Poland back in the Middle Ages, is typically made from grains or potatoes. Now comes a 21st-century version distilled from thin air. In a process that mimics photosynthesis, Air Co., of Brooklyn, uses solar-generated electricity to split water into hydrogen and oxygen, then mixes the hydrogen with carbon dioxide captured from factories to produce ethanol and water (which is siphoned off). The result is a “carbon-negative” vodka that uses more carbon than is produced during manufacturing. The liquor, which won a gold medal at last year’s Luxury Masters competition, is one of 10 finalists for the Carbon XPrize—a $20 million, five-year competition by the XPrize Foundation to turn CO₂ into marketable, carbon-based products that can make a profit despite the up-front cost of capturing the greenhouse gas. Other finalists include CarbonCure, of Nova Scotia, that infuses concrete with CO₂ to strengthen it, and Ithaca, N.Y.-based Dimensional Energy, which converts CO₂ into syngas to produce other liquid fuels, including diesel and jet fuel. If you want your vodka green, be prepared to spend a lot of green: Air Co.’s costs $65 for a 750-ml bottle. Meanwhile, with the final round of the XPrize indefinitely postponed because of the coronavirus shutdown, Air Co. is producing hand sanitizer. – T. G.
Antibiotic-immune bacteria, or superbugs, are a global health emergency that may cause an estimated 10 million deaths a year by 2050. One line of defense is wastewater treatments that use chemicals to kill dangerous pathogens. But that doesn’t fully solve the problem, because the destroyed bacteria leave behind antibiotic-resistant genes (ARGs) that can then mingle with other bacteria, making them as well more immune to antibiotics. A recent Rice University study led by Pedro Alvarez, a professor of civil and environmental engineering, investigated a treatment plant in Tianjin, China, and discovered that it was discharging five different strains of potentially harmful bacteria for each one treated. “The aeration tank is like a luxury hotel where all bacteria grow,” Alvarez says. Treated, but still pathogen-filled, wastewater is discharged back into waterways, which is why superbugs are often found in aquatic systems and adjacent soils. Pingfeng Yu, a postdoc and coauthor of the Rice paper, says if that water is then reused, without further treatment, for non-potable purposes such as irrigation, the bacteria can once again endanger people: “It’s important to remove these superbugs [from wastewater] as well as their resistance genes. Otherwise, there will be an increased human exposure to associated risks.” The solution that Alvarez’s team came up with is molecular-imprinted graphitic carbon nitride nanosheets that “trap and zap” the extracellular ARGs before they can infect other bacteria. When included in a mixture containing ARGs and exposed to ultraviolet light, the nanosheets were 37 times more efficient at destroying the genes than graphitic carbon nitride alone. – T. G.
©Alvarez Research Group/Rice University
Construction in permafrost regions such as Alaska has always been tricky. Because thawing soil can threaten the integrity of buildings, engineers must design structures that can be erected and maintained without melting or eroding the permafrost. The challenge is increasing because of global warming, warns a recent National Academy of Engineering report from engineers at the University of Alaska in Fairbanks and Anchorage. Engineers also need to predict how localized thaws might affect a structure and include solutions for keeping it stable. It’s less of an issue for unheated buildings, roads, or railways. But heated buildings and warm pipelines require separation from the ground, by ventilated space and pilings frozen into the permafrost, to prevent thawing. In some cases, insulation and cooling systems are installed beneath buildings. The NAE report estimates that by 2050, 70 percent of Arctic infrastructure will occupy areas at risk from permafrost thaw and ground subsidence. However, many modern technologies—the study highlights remote sensing, modeling, and imaging techniques—can help engineers overcome the big melt. One resource it cites is the new National Science Foundation-funded Permafrost Discovery Gateway, a browser-based platform for visualizing and exploring big data from satellite images of Arctic regions. Users can dig into historical data and predictions about changes in ice-wedge degradation, surface-water coverage, thaw slumps, and erosion of ocean, river, and lake shorelines. – T. G.
Light Speed Ahead
All rockets use propellants, which blast in the opposite direction of a liftoff. Over the years, scientists have tried to come up with propellant-less engines but were undone by basic physics. That hasn’t put off David Burns, an engineer at NASA’s Marshall Space Flight Center in Alabama, who recently posted a paper describing a plan for a propellant-less “helical engine” that makes use of mass-altering effects that occur at near-light speed, according to New Scientist. Here’s how it could work: Picture a box sitting on a frictionless surface. Inside it there’s a rod on which a ring slides, pushed by a spring. As the ring slides along, its recoil propels the box in the opposite direction. When the ring hits the other side and heads back again, the box also changes direction, resulting in the box sliding back and forth. But, says Burns, if the ring’s mass is greater when it glides in one direction than in the other, its action would exceed reaction, and the box would continuously zoom forward. Objects do gain mass as they approach light speed, the article notes, which is something particle accelerators account for. To drive a spacecraft, Burns’s engine would use a helix-shaped accelerator. A big one. It would need to be 200 meters long and 12 meters in diameter and require 165 megawatts of power to generate a mere 1 newton of thrust. But he reckons it could reach up to 99 percent of the speed of light in space, where there’s no friction. Other experts are skeptical. And Burns, who developed the theory on his own without NASA sponsorship, admits his idea may prove to be more science fiction than science fact. But he’s okay with that, telling New Scientist: “You have to be prepared to be embarrassed. It is very difficult to invent something that is new under the sun and actually works.” – T. G.