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Investor Relations



Sotirios J. Vahaviolos
Founder and Executive Chairman

Dr. Vahaviolos is our Executive Chairman, and until August 10, 2017, had been our Chairman and Chief Executive Officer since he founded Mistras in 1978 under the name Physical Acoustics Corp. Prior to forming Mistras, Dr. Vahaviolos was a scientist and manager at AT&T Bell Laboratories. Dr. Vahaviolos received a B.S. in Electrical Engineering and graduated first in his engineering class from Fairleigh Dickinson University and received a Master of Science (EE), Masters in Philosophy and a Ph.D.(EE) from Columbia University School of Engineering. During Dr. Vahaviolos’ career in non-destructive testing, he has been elected Fellow of (1) The Institute of Electrical and Electronics Engineers, (2) The American Society of Nondestructive Testing, and (3) The Acoustic Emission Working Group (AEWG). Dr. Vahaviolos is also a member of The American Society for Nondestructive Testing (ASNT), where he served as its President from 1992-1993 and its Chairman from 1993-1994, a member of AEWG and an honorary life board member of the International Committee for Nondestructive Testing. Additionally, he was the recipient of ASNT’s Gold Medal in 2001 and AEWG’s Gold Medal in 2005. He was also one of the six founders of NDT Academia International in 2008.

Dr. Vahaviolos brings to the Board his detailed knowledge and unique perspective and insights regarding the strategic and operational opportunities and challenges, economic and industry trends, and competitive and financial positioning of our business. In addition, his significant experience as the company’s founder, Chairman and CEO, his leadership of our Company for almost four decades during various economic cycles and his 40% ownership interest in the Company positions him well to serve as our Executive Chairman.

Dennis M. Bertolotti
President and Chief Executive Officer (CEO)

Dennis M. Bertolotti is the President and Chief Executive Officer of MISTRAS Group, having previously served as Group Executive Vice President, Chief Operating Officer, and President of Services of the Americas. Mr. Bertolotti has been with MISTRAS since MISTRAS acquired Conam Inspection Services in 2003, where Mr. Bertolotti was a Vice President at the time of the acquisition. Mr. Bertolotti has been in the NDT business for over 25 years, and previously held ASNT Level III certifications and various American Petroleum Institute certifications, and received his Associate of Science degree in NDT from Moraine Valley Community College in 1983. Mr. Bertolotti received a Bachelor of Science and MBA from Otterbein College.

Michael J. Lange
Senior Group Executive VP Business Development & Strategic Planning

Michael J. Lange is Senior Group Executive VP Business Development & Strategic Planning. He joined MISTRAS when it acquired Quality Services Laboratories in November 2000. He was elected a Director in 2003, and served as Vice Chairman of MISTRAS’ Board of Directors from 2003-2019. Mr. Lange is a well-recognized authority in Radiography and has held an ASNT Level III Certificate for almost 20 years. Mr. Lange received an Associate of Science degree in NDT from the Spartan School of Aeronautics in 1979.

Michael C. Keefe
Executive Vice President, General Counsel and Secretary

Michael C. Keefe is Executive Vice President, General Counsel and Secretary, positions he has held since he joined Mistras in 2009. Previously, Michael served in various legal roles with AT&T and Lucent Technologies for 15 years, his last four years as Law Vice President, Corporate. Between his time at Lucent Technologies and Mistras, Michael worked at International Fight League, a sports promotion company, as Executive Vice President, General Counsel and Corporate Secretary, and eventually its President, General Counsel and Chief Financial Officer and led the sale of the company's assets and the Chapter 11 liquidation of its operating subsidiary. Prior to joining AT&T, Michael was in private law practice at New Jersey's largest law firm, McCarter & English, LLP. Michael graduated with a Bachelor of Science in Business Administration (Accounting) from Seton Hall University and a Juris Doctorate, cum laude, from Seton Hall University School of Law. Before starting his legal career, Michael served as a Certified Public Accountant for Coopers & Lybrand, a predecessor firm to PricewaterhouseCoopers, LLP. He worked in the accounting profession for seven years before commencing his legal career.

Edward J. Prajzner
Executive Vice President, Chief Financial Officer (CFO) and Treasurer

Edward J. Prajzner is Executive Vice President, Chief Financial Officer and Treasurer.  He joined MISTRAS in January 2018.  Before joining MISTRAS Group, Mr. Prajzner was Chief Financial Officer and Secretary of CECO Environmental Corp, a publicly-traded global diversified and energy technology company. He began his career with Ernst & Young and also held senior financial positions with CDI Corporation and American Infrastructure.  Mr. Prajzner earned a Bachelor of Science degree in Accountancy from Villanova University, an M.B.A. (Finance) from Temple University and is a Certified Public Accountant.

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