Research assistant Lamont-Doherty Geological Observatory, Columbia University, Palisades, New York, 1972-1973;technical specialist, American Museum Natural History, New York City, 1973-1981;research scientist, The Metropolitan Museum Art, New York City, since 1981. Chairman session coordinator international biodeterioration conferences, 1989, 90, international electron microscopy conferences, 1986, 87. Coordinator International Council of Museums-CC Biodeterioration working group, 1992-1995.
Consultant to American Research Center, Egypt, NOVA, World Monument Fund, International Centre for the Study of the Preservation and Restoration of Cultural Property, Rome. Chairman American Technology Committee of the Corpus Vitrearum of Medeii, since 1991, chairman emeritus, since 1994. Adjunct Professor Institute.Fine Arts, New York University.
Session chairman International Centre for the Study of the Preservation and Restoration of Cultural Property International Colloquium, 1995. Program chairman International Biodeterioration and Biodegradation Symposium, 1999.
1972 - 1973
1973 - 1981