Arthur L. Ruoff, professor emeritus and former director of the Department of Materials Science and Engineering, died Jan. 14 in Ithaca. Ruoff was 94.

“He was a great colleague,” said Roald Hoffmann, the Frank H. T. Rhodes Professor, Emeritus, in the Department of Chemistry and Chemical Biology in the College of Arts and Sciences, and winner of the 1981 Nobel Prize in chemistry.

“There was another center of high-pressure research at Cornell, in the work of William Bassett in Geological Sciences. And theory – ingenious quantum mechanical ideas from Neil Ashcroft,” Hoffman said. “I think Ruoff, Bassett and Ashcroft, in different departments, combined to make Cornell a world-class center for high-pressure research.”

When Ruoff came to the university in 1955, Cornell Engineering’s materials science work focused on metallurgy. Physicists around the world could only speculate on how matter might behave under ultrahigh pressures.

When Ruoff retired in 2006, he had achieved unheard of static pressures – equal to 5.6 million times those seen on the surface of the Earth. He’d also pioneered new tools and processes, and helped found the Department of Materials Science and Engineering and launch the Cornell High Energy Synchrotron Source (CHESS).

Ruoff was born Sept. 17, 1930, in Fort Wayne, Indiana, and raised on a farm outside the city. In an oral history interview with Hoffmann in 2014, Ruoff recalled working with his uncle, an expert in mechanical and electrical equipment. When his uncle was drafted during World War II, a young Ruoff took over and learned to run or repair everything he could find.

That practical knowledge combined with academic insights gained as an undergraduate at Purdue University studying chemistry and physics. When he reached the University of Utah for graduate study with renowned theoretical chemist Henry Eyring, Ruoff was introduced to two things that would change his life — the groundbreaking high-pressure work of 1946 Nobel Prize winner Percy Bridgman, and his future wife, Enid. The couple married in 1954; Ruoff earned his Ph.D. in physical chemistry a year later.

Working out of a Quonset hut in Utah, Ruoff was approached by two visitors. Sent by Cornell Engineering Dean Solomon Hollister, the pair recruited Ruoff to help the college advance its theoretical and experimental materials research.

And that he did.

When early equipment limited his work to 3 gigapascals (GPa), or 30,000 times atmospheric pressure, Ruoff helped pioneer the “diamond anvil.” In this device, two 16-sided diamonds are stacked nose to nose with small flat areas, originally just 20 microns and progressively smaller, ground into each tip. Pressed together within a gasket of high-strength steel, this diamond anvil could reach static pressures many times higher than previously achieved. When CHESS came online, Ruoff and his team pioneered ways to compress high-energy X-ray beams and send them through the diamonds, creating new ways to measure how materials reacted.

Across five decades and 320 academic publications, Ruoff and his team repeatedly broke new ground. In 1987, the lab was first to reach 95 GPa and transform oxygen into a silver metallic substance, then transformed sulfur into a superconductor in 1992. The lab advanced to 250 GPa and proved that silicon could be squeezed through seven phases and into a metallic superconductor. In 1990 the lab was the first to surpass the pressure at the center of the Earth (360 GPa) and reach 416 GPa.

In 1998 the lab dispelled theory and demonstrated that hydrogen would not phase into a supreme superconductor even when subjected to 342 GPa. Before his work was done, Ruoff’s anvil reached an unprecedented 560 GPa.

“The innovation in Art Ruoff’s work was in optimization of diamond shaping to achieve higher pressures as well as in micro-collimation of X-ray beams to study materials,” said Yogesh Vohra, a former postdoc in Ruoff’s lab on the oxygen research team, and now a professor of physics and associate dean at the University of Alabama. “Working with Dr. Ruoff broadened my horizons to materials science and engineering.”

Ruoff received a number of awards, including the highest honor in his field in 1993 – the Bridgman Award, given by the International Association for Research at High Pressure and Temperature, and named after the man who inspired his career. A dedicated educator as well, Ruoff also received the Westinghouse Award for Outstanding Teaching and a National Science Foundation teacher fellowship.

To some, however, Ruoff is best remembered for his work with less exotic materials.

“When I am 15, my dad invites me to his research lab at Cornell,” said Jeffrey Ruoff ’85, now an associate professor of film and media studies at Dartmouth College. “He takes a jar of Jif creamy peanut butter – my favorite, and 97% carbon – and puts it in the instrument. Ten minutes later, he pulls it out. A diamond.”

Art and Enid Ruoff raised five sons in Ithaca. Four – William ’78, Stephen ’79, Rodney ’81 and Jeffrey – were varsity athletes and earned bachelor’s degrees from Cornell, with William, Rodney and Jeffrey later earning Ph.D.’s and Stephen founding a successful Lansing, New York-based materials research company. Kenneth, also a student-athlete who graduated from Harvard in 1989, went on to earn a Ph.D., as well.

Steve still has a letter from his father, written to all five sons in 1974, pledging to pay for all their college costs and most of their other expenses, provided they commit to “hard study.”

“He loved his work, both teaching and research,” Steve Ruoff said. “He worked very hard, and would justify the long hours by saying, ‘This is easy compared to farming.’”

Art Ruoff became a coach, manager and ultimately the director of the Ithaca Youth Hockey Association. He was a member of the Faculty Senate, and served on the executive committee for CHESS. After his retirement, he spent a decade researching economics and energy policy, publishing the book “The Declaration of Energy Independence” in 2012.

Ruoff was preceded in death by his wife, Enid, and son Bill. He is survived by four sons and 10 grandchildren.

John Carberry is a freelance writer for Cornell Engineering.