Breakthroughs and trends in the world of technology
Walk ‘N’ Roll
Researchers have invented a spray that can be applied to tiny—think insect-size—inanimate objects and turn them into “millirobots,” Science reports. A multiuniversity team led by investigators at City University of Hong Kong came up with a biocompatible compound that contains iron particles, polyvinyl alcohol, and gluten. When mixed with water, the compound can be sprayed onto materials, coating them with a sticky magnetic skin the researchers call M-skins. By applying an electric field, the M-skin-coated materials can be made to move.
The team demonstrated the technique on several objects, including origami paper and cotton thread, making the millirobots crawl, walk, roll, and even swim. They also demonstrated potential medical uses, guiding a thread-like catheter covered in M-skin through a model blood vessel and delivering robotic egg-shaped drug-delivery capsules into the stomachs of anesthetized living rabbits. – Thomas K. Grose
©City University of Hong Kong
Rings of Fire
A blue whirl may sound like a fairground ride, but it’s actually a highly efficient, clean-burning flame that’s only recently been discovered, thanks to a freak accident. In 2003, lightning hit a bourbon warehouse in Kentucky, setting aflame 800,000 gallons of booze, some of which leaked into a nearby creek, causing a massive fire tornado. Aerial footage of the fiery twister caught the attention of researchers, who, curious about the lack of soot, decided to investigate the phenomenon as a potential method of oil spill remediation. More recent laboratory experiments have revealed that raging fire tornadoes eventually transform into much more stable blue whirls. Now, investigators at Texas A&M University and the University of Maryland, using numerical simulations produced by supercomputers, have determined that blue whirls are composed of three different flames: a diffusion flame and premixed rich and lean flames. The trio combines in a fourth structure, a triple flame that looks like a spinning blue ring. A blue whirl can burn many types of hydrocarbon fuels very efficiently without producing soot. The hope is that these flames can be controlled and used to burn fuels more cleanly. – T. G.
When recent mechanical engineering graduate Victor Nicolov, 26, was looking for ideas to jump-start his British Columbia-based company, Anvy Technologies, he found inspiration in his balky kitchen garbage disposal. Researching the problem, he learned that some cities have banned the machines for causing blockages in home plumbing and even farther down the line in public sewer systems. He also saw opportunity in the “waste of free waste that could be used for soil amendment or generating energy.” Sepura, the under-sink recycling device he developed, made Time magazine’s 2020 Best Inventions list. To separate food waste, an auger inside a porous pipe first extracts all the water and then deposits the residue in an odorless bin. A series of LED lights indicate when the bin should be emptied for composting or curbside collection. Since there’s no grinding, the Sepura system can rely on a much smaller motor that consumes 20 times less power than that of a regular garbage disposal. Plus, it is quieter and requires no water. “I wanted to keep the device as simple as possible and self-cleaning,” Nicolov explains, noting that eco-friendly products often are harder to use or cost more. “Being green should be easy.” His company is currently taking pre-orders for delivery later this spring. – Pierre Home-Douglas
Victor H. Benitez, a professor of mechatronics at Tecnologico de Monterrey in Mexico, and two of his undergraduates have designed a low-cost electromechanical arm that could help engineering instructors remotely demonstrate complex robotic concepts such as kinematics. Without physical demonstrations, the mathematical equations that explain the way robots move can be hard to understand. According to Tech Xplore, two of Benitez’s students, Rodrigo Symonds and David Elguezabal, after studying kinematics in a remote class during the COVID-19 lockdown last March, came up with the idea of building a robotic arm with Internet-of-Things connections for their class project. Unlike most commercial robotic arms, this one can be built cheaply using off-the-shelf parts without advanced tools. The Wi-Fi-enabled device, which can be controlled from afar with an online app, lets teachers and their students conduct experiments all using the same arm. Moreover, the program provides access to all the commands and parameters underlying the arm’s movements, which helps students understand the processes that guide its behavior. The electromechanical arm is an open-source device and thus easily modifiable. Instructors anywhere in the world have access to the design and can adapt it to specific needs, including using the arm to explain topics from complex math formulas to 3-D printing to programming. – T. G.
©Victor H. Benitez, Rodrigo Symonds, and David E. Elguezabal
Debris is a major peril in low orbit. Some 152 million bits of broken or destroyed spacecraft—some as tiny as 1 millimeter, others larger than softballs—are circulating at speeds up to 17,500 mph, posing a threat to the roughly 1,800 satellites now aloft as well as to thousands more scheduled. Engineers have proposed several potential high-tech garbage collectors. But Japanese researchers may have a simpler way to both protect and prevent satellites from spreading shards in the first place: build them out of wood. The BBC reports that a research team led by Takao Doi, a former astronaut and an engineering professor at Kyoto University, is working with Sumitomo Forestry, a Japanese logging company, to develop a prototype housing. The idea is that once the satellite’s working life ends, it could fall back into the atmosphere and safely burn and disintegrate. Popular Mechanics further quotes the newspaper Nikkei Asia as noting that wood does not interfere with the electromagnetic waves that satellites use to communicate, so antennas and other instruments could be placed inside a wooden compartment. That still invites the question of what happens to the electronic components upon reentry. For now, however, researchers are testing various types of wood—the exact types are an “R&D secret,” a company spokesman tells the BBC—in extreme environments here on Earth. If the results are A-Oak-Kay, the team hopes to launch a trial wooden satellite by 2023. – T. G.
Scents and Sensibility
When the Manduca sexta, a type of hawk moth, is searching for food or a mate, it uses its antennae to detect airborne aromas. Researchers at the University of Washington have harnessed that capability on small drones designed to pinpoint certain odors. The so-called Smellicopters could be used to sense gas leaks or other toxic plumes in areas hit by natural disasters or to zero in on chemicals used in explosive devices. The autonomous vehicle uses a live moth antenna wired to an electrical circuit that measures and decodes signals coming from the antenna’s cells. (The moth is first refrigerated to anesthetize it before the antenna is removed.) The antenna remains biologically and chemically active for up to four hours. The Smellicopter is based on a commercially available small drone with an open-source platform that lets users add new features. Its “cast and surge” protocol means the drone flies to the left and then to the right over a search area, surging toward any odor it detects. The device, which relies on a camera to see, doesn’t use GPS, so it can easily be used indoors, underground, or inside mines and pipes. – T. G.
Many industrial activities, including mining and smelting, generate copious amounts of arsenic, a heavy metal toxin that can end up in soil and groundwater, infiltrating crops and endangering the humans who consume them. Long-term exposure has been linked to ailments ranging from cardiovascular disease to diabetes, birth defects, and cancer. Arsenic contamination is relatively common in many agricultural products, particularly rice, vegetables, and tea. Conventional methods to measure arsenic levels in soil include sampling soil and plant tissues and mass spectrometry analysis—all of which takes time and typically requires large, costly equipment. Now scientists at the Singapore-MIT Alliance for Research and Technology have found a way to embed nanoscale sensors into living plant leaves to detect arsenic levels in real time. The optical nanosensors change their fluorescence intensity when they detect arsenic, and those changes can be read using a portable, inexpensive electronic device. The researchers say the technology, which does not harm the plants, not only is easier and cheaper to deploy but is also more accurate than current methods. – T. G.
©Singapore-MIT Alliance for Research and Technology; Christine Daniloff, MIT
Josephine Allen, an associate professor of materials science and engineering at the University of Florida, studies sex-based disparities in health care—notably how cardiovascular disease affects women, particularly Black women. Yet researchers rarely mention the sex of the cells they use in their work. How rarely? A review of top biomedical and biomaterials journals by Allen and her team found that a mere 3 percent of published papers mentioned the sex of the cells used in studies. Allen saw this as a big problem, since small differences in data can skew results. “There is overwhelming evidence that male and female biology is different, and these biological differences translate to disparities in health and disease,” she says. According to Allen’s paper, the three main reasons for the failure to mention cell sex are: researchers just don’t bother to note it; cell vendors don’t often make the information available; and journal editors don’t require the data. Her team’s study was recently published in Advanced Healthcare Materials, one of the publications mentioned for failing to note cell sex. The journal has since begun discussions on implementing a new policy on reporting the sex of cell lines, which Allen considers “a small victory.” A goal of medical research is personalized health care, she adds, but that may not be possible if biomedical and biomaterials researchers don’t take sex into account. – T. G.
Wastewater treatment systems in the United States consume 2 percent of all electricity produced, and a big chunk of that power goes into removing nutrients from human waste flushed down the toilet. Urine is rich in nitrogen, phosphorus, and potassium—key ingredients of crop fertilizers used for thousands of years. Researchers have investigated ways to recycle urine as a way of reducing the amount of electricity and chemicals needed to clean wastewater. But the energy needed and costs to collect and transport the urine, then ship the fertilizer to farmers, were prohibitive. A University of Michigan study, the first in-depth analysis of “peecycling,” finds that the benefits of a urine-reclamation system would outweigh those costs and reduce greenhouse gas emissions, energy and water consumption, and algal blooms. Only a handful of demonstration peecycling plants exist, including one at UMich. Data from it and another plant at the Rich Earth Institute in Vermont were used to build the researchers’ model of likely environmental impacts, which were then compared to the performance of standard, large-scale treatment facilities in Michigan, Vermont, and Virginia. The study found that peecycling also could eliminate the need for some wastewater treatment chemicals. – T. G.
Cornell University has set a goal of using only renewable energy by 2035—an ambitious target in upstate New York, where winters are long, cold, and snowy. But the land-grant school has a secret source of renewable natural gas (RNG): 600 dairy cows. Plans call for using microbes to process their manure into biogas, a mixture of carbon dioxide and methane. The CO₂ combined with hydrogen, produced by renewable electrolysis of nearby lake water, makes RNG, which can then be fed into the natural gas grid. Bovine biogas could provide 97 percent of the school’s total annual peak heat demand. An additional 19 cows would raise that to 100 percent. Meanwhile, British start-up Zelp is tackling the opposite end of methane production with a face mask designed to reduce the amount of greenhouse gases in bovine belches by 60 percent, Wired reports. The mask doesn’t cover a cow’s mouth or nostrils. Instead it contains sensors that measure methane levels in burps and breathing. If the level gets too high, the mask captures and shunts the gas into an oxidation mechanism that converts the methane into CO₂ and water, which then is expelled. Zelp claims its product reduces methane’s global warming potential to less than 1.5 percent of its original value. Now that’s an output worth ruminating on! – T. G.
Desalination, the technology that turns seawater potable, is costly, inefficient, and energy intensive. Most desalination plants use reverse osmosis, forcing high-pressure water through porous membranes to filter out the salts. Now researchers at the University of Texas–Austin and Penn State have discovered why the process is so inefficient. They figured out that the membranes are inconsistent in density and mass distribution, which causes performance to falter. The team then designed and made membranes with uniform density at the nanoscale, which made them 30 percent to 40 percent more efficient, saving energy. Meanwhile, Washington State University researchers have devised a microbial fuel-cell system that uses the microbes in wastewater to create a chemical reaction to generate electricity. Traditional wastewater plants are energy-intensive because they pump oxygen into the water nonstop. Aeration encourages the growth of bacteria that consume organic matter and help scrub contaminants. The fuel-cell method doesn’t require aerating the water. Instead the cells run on the electrons generated by the bacteria as they do their metabolic work. The electricity the cells produce can then be used for other plant needs or additional aeration. The system could one day be used at small treatment plants in rural areas, independent of the power grid. – T. G.
©Enrique Gomez, Penn State; Baskar Ganapathysubramanian, Iowa State; and Greg Voss, UT Austin
Reinventing the Wheel
Chemical engineers at the University of Pittsburgh have shown it’s possible to build a two-dimensional wheel that can transform itself into a gear—the key part of all mechanical engines. Essentially, they created an internal combustion engine at the millimeter scale that does not rely on a traditional, external power source, one researcher explains. Instead, the gear is powered by adding a reactant to the solution in which it’s immersed. Using a computer simulation, the Pitt team created a hexagon-shaped spoked wheel from a flexible, two-dimensional sheet just 1 millimeter wide. Catalysts were added at various locations along its rim. After placing the wheel in a fluid-filled microchamber, a reactant was added that activated the catalysts, causing the fluid to flow. The inward flow of the liquid forced lighter sections of the flat wheel to pop up, essentially becoming a rotor that caught the flow and started spinning. The researchers say their demonstration shows the potential for using chemicals to drive small-scale machines and soft robots. – T. G.
©University of Pittsburgh
Changing the dressings on burns and other types of wounds can be a delicate and painful process. Physicians have used electrospinning machines that apply electricity to a solution to create nanofibers that can be used as breathable bandages. But the machines are large and immobile, limiting their use on patients who are often bed-bound. Nanomedic, an Israeli biotech firm, has developed a laser-guided gun that uses a compact version of that technology to spin out a web of fibers to cover burns and wounds with a “skin substitute,” the Guardian reports. Small, portable, and battery-powered, the device can be used at bedside. The dressing is waterproof, so patients can take showers. It’s also translucent, which means doctors can examine a wound without having to remove the bandage. So far, Nanomedic’s Spincare device is available only in Europe and Israel, but the company plans to enter the U.S. market soon. Meanwhile, on the other side of the globe, Andy Zeller, a New Zealand research chemist, has invented a smart bandage that changes colors if a wound becomes infected, according to the New Zealand news outlet Stuff. The bandage is made from elastomers and a type of nanocrystal that has antimicrobial properties. The crystals react to chemicals released by an infected wound, causing the bandage to change from white to red. – T. G.