Pearl millet, a hardy grain that is abundant in even the harshest regions of Africa and India, is a staple for many of the world’s poorest people. But removing the edible seed from the chaff is hard work. Traditional threshing techniques usually involve women pounding the plant with mortar and pestle.
Over the summer, Michelle Marincel, NucE’06, MS EnvE’08, helped design an ergonomic threshing machine to provide some relief to that back-breaking work. She was part of a group of students chosen to attend the International Development Design Summit at Massachusetts Institute of Technology. The students joined professors and professionals in groups of 10 to work on projects aimed at addressing issues related to poverty.
“A researcher provided panicles of pearl millet for us to roll up our sleeves and destroy as we struggled to understand the best way to remove the grains from the stalk,” says Marincel. “Ultimately, we discovered the physics behind millet threshing. We tried numerous iterations of threshing devices. We tried using rubber, brushes, vacuums, centrifuges and many odd materials to remove the grain.”
They hit upon creating a machine that works like a bicycle. “The key we discovered is hitting the grains at high speeds in the right direction,” she says. “Our idea is that a woman on a bicycle could carry, on her back, an extra wheel for the purpose of threshing. When she reaches the field, she could turn her bicycle upside down and change out the back wheel for threshing. This gives mobility to harvesting.”
Marincel says members of her group will stay in touch in order to prepare the bicycle thresher for field tests.