No description available.

Thesis (M.S.)--Ohio University, August, 1985. / Title from PDF t.p.

Thesis (Ph. D.)--Hong Kong University of Science and Technology, 2002. / Vita. Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

Thesis (M.S.)--University of Wisconsin--Madison, 1983. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 196-197).

Thesis (M.S.)--University of Wisconsin--Madison, 1962. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 32-33).

The success in fabrication of various nano-sized powders, wires or tubes has arisen the new possibility in modifying the existing commercial materials in terms of their functional or structural characteristics. In this study, the AZ61 Mg alloy is adopted as the matrix, and nano-sized SiO2 particulates are introduced into the alloy by means of casting, powder metallurgy, or spray forming processes to fabricate a high performance Mg matrix composite. The strengthening mechanisms, fracture toughness and bending toughness of the AZ61 Mg based composites are examined. The composites were prepared either by spray forming, ingot metallurgy, or powder metallurgy, followed by severe hot extrusion. The spray formed composites exhibit the best nano particle distribution and toughness, but the volume fraction of the nano particles that can be inserted is limited. The nano composites fabricated through the powder metallurgy method possess the highest strength due to the extra strengthening effect from the MgO phase. Strengthening analysis based on the Orowan strengthening mechanism can predict well the composite strength provided that the nano particles are in reasonably uniform dispersion. For composites containing higher nano particle volume fractions greater than 3%, the experimental strength data fall well below the theoretical predictions, suggesting poor dispersion of the reinforcement. The creep properties of the composites are also explored. The specimens are subjected to tensile loading at temperatures 200 to 400oC and strain rates 1x10-3 to 1x10-1. The creep mechanism is identified as dislocation creep controlled with the rate controlling diffusion step being the magnesium lattice diffusion at low strain rates and grain boundary diffusion at high strain rates.

Abstract A piano is called ¡§the king of instruments¡¨. Almost every great musician writes good compositions for piano, and they are also good pianoists. Piano almost appears in every concert. Bartolomeo Cristofori made the first instrument that we recognize as a piano today in 1709.It is an important invention in music history. The basic structure of a modern piano was approximately decided in 19 century. Many patents were designed to improve the performance of piano in these years, but they didn¡¦t change the basic structure of piano. The research adopts the method of structure synthesis to design new piano and brings up a new idea ¡§linkage controls a hammer¡¨ to improve the performance of a piano.

Thesis (Ph. D.)--Ohio State University, 1969. / Includes vita. Includes bibliographical references (leaves 131-134). Available online via OhioLINK's ETD Center.

Thesis (M.S.)--Ohio University, June, 2001. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1992. / Title from PDF t.p.