Boyd A. Clark, 51, has joined CTLGroup as director of the materials laboratory. He will lead the firms materials testing in its chemical, physical and mortar laboratories and work with its scientists and specialists on complex materials. Clark has spent more than 20 years in laboratory management and materials science; new product design; and research, analysis and investigation of building materials. Clark received his Ph.D. in the intercollege materials program at Pennsylvania State University, an M.S. in materials science and engineering and a B.S. in materials science and engineering at the University of California at Berkeley.