Bipin Parekh, Ph.D., is senior consulting engineer at Entegris. He has many years of experience in fluid contamination control and purification for semiconductor manufacturing. He can be reached at Entegris, Inc., 129 Concord Road, Billerica, MA 01821; 978-436-6636; Bipin_Parekh@entegris.com; www.entegris.com.