Research suggests double-masking can bolster protection, making for a better fit over the mouth and nose with less open space at the edges. At the same time, there is a shortage of clinical-grade personal protective equipment (PPE) in multiple regions. But what if a metaphorical copying machine could crank out 2,000 masks an hour? Andre Sharon, a Boston University College of Engineering professor of mechanical engineering, says such a newly developed device that does just that sits in a Saint Mary’s Street building on the BU campus.