Thomas C. Leonard will succeed Richard A. Johnson as chief accounting officer and chief financial officer of Dynasil Corp. of America, effective Feb. 4, the company announced Thursday. Leonard brings to Dynasil more than 30 years of accounting, management and leadership experience. Prior to his appointment, he served as chief financial officer of Pennichuck Corp. of Nashua, N.H., for four years. He also spent 15 years in public accounting with Arthur Andersen LLP, where he became an audit partner and audit division head. Dynasil develops and manufactures detection and analysis technology, precision instruments and optical components for the homeland security, medical and industrial markets. For more information, visit: www.dynasil.com