Dr. Sotirios J. Vahaviolos is the Founder and Chairman CEO of Physical Acoustics Corporation (PAC) in 1978 and it's parent the MISTRAS Group, Inc. in 1994.

After finishing No. 1 in his Science and Engineering class at Fairleigh Dickinson University with a BSEE in 1970, he became the recipient of the prestigious AT&T Bell Telephone Laboratories Graduate Study Program on a full-time Scholarship to attend Columbia University as Doctoral Candidate. In 1972, he received his MSEE and in 1976 his Ph.D., both from Columbia University School of Engineering. In 1975 he also received a Masters in Philosophy from Columbia University.In 1978, Dr. Vahaviolos, after licensing his AT&T patents, founded PAC.

Dr. Vahaviolos is an elected Fellow of the Institute of Electrical & Electronic Engineers (IEEE), the American Society of Nondestructive Testing (ASNT) and the Acoustic Emission Working Group. Additionally, he is an elected member of the New York Academy of Science, the Sigma Chi Scientific Society and the American Society of Testing & Materials. He is a senior member of the Instrument Society of America and other scientific and honorary societies. He is mentioned in "Marquis Who's Who in America", "Who's Who in Science and Engineering", "Who's Who in Finance and Industry", and "Who's Who in the World".