Drones and other aircraft effectively spray pesticides over miles of crops, but the method also can pollute the environment if wind carries the mist off-target.
One of the problems is that tiny droplets are hard for aerial crop sprayers, inkjet printers and a wide range of other machines to control. Purdue University engineers are the first to come up with the math formula that was missing to measure a key property of these droplets.
“There are many properties that affect how a droplet forms. One of those important properties is surface viscosity, which people have had a heck of a time trying to measure because they just didn’t have the tools to do it,” said Osman Basaran, Purdue’s Burton and Kathryn Gedge Professor of Chemical Engineering.
Pesticides and other chemicals contain additives called surfactants. These surfactant molecules resist each other at a liquid’s surface, giving rise to a sticky force called surface viscosity that can make the droplet smaller. The higher the surface viscosity, the more compact a droplet’s shape.
Read more at Purdue University
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