Zirconium titanate dense materials are proposed for many structural applications, but fully reacted and completely dense pieces are difficult to obtain by conventional routes.
"I was once having lunch with him," Mr. Hurwitz recalled, "and I said: 'Almost all of your pieces are difficult for American orchestras to play because the instrumentation is so unusual.
To the modern eye, these solos and ensembles appear simple, an observation to which the present Duncan dancers react defensively by pointing out that the pieces are difficult to perform.
"Many of these pieces were difficult to see at the Morgan because of the way some of the objects were displayed in the study, which is maintained as a period room," Mr. Barnet said.
University president Hazel O'Leary, a 1959 Fisk alumna who was President Bill Clinton's first Secretary of Energy (1993-97), Thed Tennesseansean that the decision to sell the pieces was difficult but necessary for the private college to remain competitive.
Larger, finer pieces are difficult to find.
Longer work pieces are difficult to true, and maintaining a uniform diameter along the length of a longer piece can take a lot of work.
Where the tone of the piece is difficult to predict.
If removing the piece is difficult, the team could have to shut down the machine and then warm it back up, which could take as much as five weeks in total.
"I think probably the only piece we've ever done that approaches Mahler Nine is 'The Rite of Spring' by Stravinsky -- we've done that a couple of times, although it's not nearly as long". The Mahler piece is difficult both in its composition and in its themes, according to Pratt, requiring much concentration by him and the student musicians.
