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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 | O C T O B E R 2 0 1 8 7 PERMANENT MAGNETS: PRINT, POWER, REPEAT Oak Ridge National Laboratory sci- entists have improved a mixture of ma- terials used to 3D print permanent mag- netswith increaseddensity, whichcould yield longer lasting, better perform- ing magnets for electric motors, sen- sors, and vehicle applications. Building on previous research, they combined thermoplastic nylon polymer with neo- dymium-iron-boron magnet powders into pellets of feedstock materials. Using innovative additive manu- facturing techniques allows the team to print permanent magnets into com- plex shapes without wasting material. Plus, the resulting magnets can be con- verted back to a feedstock and reprint- ed as new magnets, if needed. “This is especially important con- sidering magnets of this caliber are typically made with critical rare earth elements, which are in short supply and difficult to acquire,” says researcher Parans Paranthaman. ornl.gov. CRAB SHELLS AND TREES AS CO-STARS OF NEW FILM Researchers at Georgia Institute of Technology have created an un- usual material that has the potential to replace the flexible plastic packag- ing used to keep food fresh. The new OMG! OUTRAGEOUS MATERIALS GOODNESS Beamline (I13-2) revealed that the melt- ing and recrystallization is responsible for changes to ice crystal size and shape during thermal abuse, whereas the changes in air bubble size and intercon- nectivity are mainly due to the bubbles coalescing. The results provide valuable in- formation to enhance the understand- ing of microstructural evolution in ice cream and other soft foods. www.diamond.ac.uk. material is made by spraying multiple layers of chitin from crab shells and cel- lulose from trees to form a flexible film similar to plastic packaging film. The team devised a method to cre- ate a film by suspending cellulose and chitin nanofibers in water and spray- ing them onto a surface in alternating layers. Once fully dried, the material is flexible, strong, transparent, and com- postable. gatech.edu . 3D-printed permanent magnets provide better performance and longer life in various applications. Courtesy of Jason Richards/ORNL. New packaging material made of chitin from crab shells and cellulose from tree fibers. Courtesy of Allison Carter/ Georgia Tech. Researchers at Diamond Light Source Ltd., U.K., agree that there’s nothing quite like ice cream on a hot day, and eating it before it melts is part of the fun. Ice cream is a soft solid and its appeal is strongly affected by the un- derlying microstructure. An international team of re- searchers brought samples to Dia- mond to investigate the tempera- ture dependence of microstructural changes—occurring during shipping, in supermarket freezers, and at home—and the underlying physical mechanisms that con- trol microstructural stability. Using 3D x-ray tomog- raphy on their first set of ex- periments, the team used ice cream samples that had been thermally abused beforehand, by cycling them between - 15° and - 5°C for a number of days. The results showed that both ice crystals and air cells within the ice cream foam grew in size for up to 14 cy- cles, with a growth rate that decreased significantly after seven cycles. Later experiments us- ing the Diamond Manchester Synchrotron measurements of the size and shape of ice crystals showwhy the very fine andmore rounded ice phase in fresh ice creammakes it taste so good. After storage and partial reheating when the ice cream is taken out of the freezer repeatedly, the ice crystals grow larger and have sharper corners, losing some of the creamy taste. Courtesy of Peter D. Lee. X-RAY TOMOGRAPHY GETS THE SCOOP ON ICE CREAM STRUCTURE