He was 65.
He died from complications of a fall at home in January, his son, Daniel, said. Hed lived with Parkinsons disease since age 35. Still, he and his family visited Normandy in April. He went rafting in the New River Gorge in West Virginia in his late 50s. And he continued hiking and backpacking for many years through the Sierra Nevada and across the Appalachians.
"Even when his mobility slowed him down, hed still find ways," his son said.
Dr. Stewart of Maumee retired in 1994 from Dura Temp Corp., which began as a project of O-I and which he and Burton Spear acquired. The manufacturer of hot-glass handling equipment is now owned by Dr. Stewarts son-in-law, Brian Summerson.
Before taking on Dura Temp in 1983, Dr. Stewart was with O-I for 19 years, beginning in 1964 after he received his doctorate in glass and ceramic engineering from Penn State University, where hed received his bachelors and masters degrees.
He became head of the glass science section in 1967 and became director of glass and ceramic research in 1970. He was appointed director of corporate research laboratories in 1972.
He was honored as the "nations outstanding young ceramic engineer" in 1974 by the National Institute of Ceramic Engineering. He was a former chairman of the glass division of the American Ceramics Society and U.S. representative to the International Commission on Glass.
"Dan to me was an excellent friend who stood by you and commanded respect as a professional and as an individual," said Richard Redwine, who retired in 1997 as vice president of manufacturing and engineering at Kimble Glass, formerly an O-I division.
"I think he had the respect of everybody who worked with him. He was straightforward and dedicated to what he was doing."
Dr. Stewarts success, his son said, was "a matter of perseverance and talent. He was a technical expert in his field and was capable of talking about his subject."
Dr. Stewart took satisfaction in volunteer efforts as a former assistant Boy Scout leader and with the Church of the Nazarene, of which he was a former board member and treasurer, his son said.
Dr. Stewart was born in New Kensington, Pa., and was president of his graduating class at Arnold, Pa., High School.