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A D V A N C E D M A T E R I A L S & P R O C E S S E S | J A N U A R Y 2 0 1 9 4 5 STRESS RELIEF STUDY SHEDS LIGHT ON DANDELION FLIGHT Scientists from the University of Edinburgh, Scotland, recently conducted experiments to understand why dandelion seeds fly so well, despite their para- chute structure being largely made up of empty space. The study reveals that a ring-shaped air bubble forms as air moves through the bristles, enhancing the drag that slows each seed’s descent. This newly found form of air bubble—dubbed the separated vortex ring— is physically detached from the bristles and stabilized by air flowing through it. The amount of air moving through, which is critical for keeping the bubble sta- ble and directly above the seed in flight, is precisely controlled by the bristle spac- ing. This flight mechanism of the bristly parachute enables the seeds’ steady flight. According to the study results, it is four times more efficient than what is possible with conventional parachute design. Researchers suggest that the dandelion’s po- rous parachute could inspire development of small-scale drones that require little or no power consumption. www.ed.ac.uk. SPOOKY SEM IMAGE APPEARS As part of her research on nanomaterials, Ashley Kaiser, a Ph.D. student at MIT in Cambridge, Mass., recently grewmillions of carbon nanotubes and immersed them in a guiding liquid. Upon drying, the resulting nanotube forest created a spooky pattern. “The initial motivation behind this work was to densify carbon nanotube forests into predictable, cellular patterns by gently wetting them with a liquid, a process that can help enable scalable nanomaterial manufacturing,” explains Kaiser. “The pattern was not precisely planned. While I knew that the carbon nanotubes would form cell-like shapes, I didn’t know that these three particular sections would spell out ‘Boo’ so nicely, so it was a pretty special find.” The image was captured using a scanning elec- tron microscope with the orange color added later as a special effect. mit.edu . CLIMATE CHANGE THREATENS BEER PRODUCTION According to new research involving the University of East Anglia in the U.K., se- vere climate events could cause shortages in the global beer supply. The study cau- tions that increasingly widespread drought and heat may cause substantial decreases in barley yields worldwide, affecting the supply used tomake beer. In recent years, the beer sector has consumed around 17% of global barley production. Results from the new study reveal potential average yield losses ranging from 3-17%, depending on the severity of weather conditions. Decreases in global barley supply lead to propor- tionally larger decreases in the barley used to make beer. During the most severe climate events, results indicate that global beer con- sumption would decline by 16%, or 29 billion liters—roughly equal to the total an- nual beer consumption in the U.S.—and that beer prices would double, on average. Even in less severe extreme events, beer consumption drops by 4% and prices rise by 15%. The researchers suggest that changes in barley supply due to extreme events will affect the barley available for making beer differently in each region. Alloca- tion of barley among livestock feed, beer brewing, and other uses will depend on region-specific prices and demand flexibilities. Their findings also show that global and country-level barley supply declines progressively inmore severe extreme event years, with the largest mean supply decreasing by 27-38% in some European countries, such as Belgium, the Czech Republic, and Germany. www.uea.ac.uk. Severe drought may lead to future beer shortages. When dandelion seeds fly, a ring-shaped air bubble forms as air moves through the bristles, enhancing the drag that slows their descent. Courtesy of Cathal Cummins. Colorized carbon nanotubes send scary message. Courtesy of Ashley Kaiser.