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Full-Text Articles in Engineering

Identification Of Tetragonal And Cubic Structures Of Zirconia Using Synchrotron X-Radiation Source, Ram Srinivasan, Robert J. De Angelis, Gene Ice, Burtron H. Davis Jan 1991

Identification Of Tetragonal And Cubic Structures Of Zirconia Using Synchrotron X-Radiation Source, Ram Srinivasan, Robert J. De Angelis, Gene Ice, Burtron H. Davis

Department of Mechanical and Materials Engineering: Faculty Publications

X-ray diffraction from a synchrotron source was employed in an attempt to identify the crystal structures in zirconia ceramics produced by the sol-gel method. The particles of chemically precipitated zirconia, after calcination below 600 °C, are very fine, and have a diffracting particle size in the range of 7-15 nm. As the tetragonal and cubic structures of zirconia have similar lattice parameters, it is difficult to distinguish between the two. The tetragonal structure can be identified only by the characteristic splittings of the Bragg profiles from the "c" index planes. However, these split Bragg peaks from the tetragonal phase in …


Automating Tolerance Synthesis: A Framework And Tools, Stephen C.-Y. Lu, Robert G. Wilhelm Jan 1991

Automating Tolerance Synthesis: A Framework And Tools, Stephen C.-Y. Lu, Robert G. Wilhelm

Department of Mechanical and Materials Engineering: Faculty Publications

This paper describes CASCADE-T—a new approach to tolerance synthesis that uses a complete representation of the conditional tolerance relations that exist between features of a part under design. Conditional tolerances are automatically determined from functional requirements and shape information. Tolerance primitives based on the virtual boundary requirements approach to tolerance representation are composed to form more complex tolerance relationships. Artificial intelligence techniques, including a constraint network, frame-based system, and dependency tracking are used to support flexible and detailed computation for tolerance analysis and synthesis.