Architecture can be significant in defining a particular place. While architecture typically offers basic shelter, its value and contributions to culture lie beyond these basic needs. The thesis proposes that by specific framing of a scenery, a view of the city can be a contribution which inspires a Precious View. / 10 / A Precious View in this case is not only about the image that we see but also the scent we smell, the sound we hear, or the wind we feel. Not only what we see matters, but all senses contribute to that what we call experience. This thesis explores ways to offer a Precious View by framing the skyline of Midtown New York.

The elastic constants, phase stability, heat of formation and the Debye temperature of various noble metal compounds in the stoichiometry A3B (where A = Pt, Ir, Rh, Ru, Pd and B = Al, Hf, Zr, Sc) were studied using the ab initio Density Functional Theory - Projector Augmented Wave method. A total of 24 compositions was investigated, of which 16 compounds were predicted to be thermodynamically stable. The remaining eight compounds were found not energetically favorable, due to positive or low heats of formation. According to the Density of States studies, the L12 structure was predicted in 8 compounds while four compounds had the D024 structure. Among compounds with the L12 structure, the hardest phase predicted was L12-Ir3Hf. L12-Pd3Sc was predicted as the least hard and most ductile compound. In compounds with the D024 structure, Pt3Zr was predicted having highest hardness and highest melting point. In all the compounds, the strongest interaction was found between hafnium and the noble metals and least interaction was with aluminum. The melting points from ab initio and molecular dynamics calculations slightly over-predicted experimental values, but showed the same trends. Both the fracture toughnesses and the melting points deduced using the Sutton-Chen potentials had similar trends to ab initio results, suggesting that the Sutton-Chen potentials is adequate for simulating metallic phases.

No description available.

No description available.

A great deal of attention has been paid to semiconductor nanowires due to their compatibility of conventional silicon-based technology. Metal-catalytic vapor-liquidsolid (VLS) and various solution-based techniques have widely been used to synthesize silicon/germanium (Si/Ge) nanowires. It is well characterized that the crystallographic orientations, diameter sizes, and surface morphologies of semiconductor nanowires can be controlled by varying process conditions and metal catalysts. Earlier experimental and theoretical studies have identified mechanism underlying metal catalyzed Si/Ge nanowire growth, involving Si/Ge diffusion into a metal catalyst, eutectic Si/Ge-catalyst alloy formation, and Si/Ge precipitation at the catalyst-nanowire interface. However, little is known about the atomic-level details of the structure, energetics and dynamics of amorphous metal alloys such as gold-silicon (Au-Si) and gold-germanium (Au-Ge) despite their importance for well controlled synthesis of Si/Ge nanowires, which is essential for the success of Si/Ge nanowires-based applications. Experiments provide many clues to the fundamental aspects of the behavior and properties of metal alloys, but their interpretations often remain controversial due largely to difficulties in direct characterization. While current experimental techniques are still limited to providing complementary atomic-level, real space information, first principles based atomistic modeling has emerged as a powerful means to address the structure, function and properties of amorphous metallic alloys. This thesis work has focused on developing a detailed understanding of the atomic structure, energetics, and oxidation of Au-Si alloys, as well as molecular mechanisms underlying Au-catalyzed Si nanowire growth. In addition, the surface reconstruction and chemistry of Si nanowires has been examined, with comparisons to planar Si surfaces. In this dissertation, based on first principles atomistic simulations, we present: 1) the atomic structure, energetics, and chemical ordering of amorphous Au-Si alloys with varying Au:Si composition ratios; 2) the behavior of boron (B) in the Au-Si alloy, such as diffusion and agglomeration, and the effect of B addition on the atomic distribution of Si and Au, with implications for in-situ doping of Si nanowires; 3) the origin and structural ordering of Si surface segregation in the Au-Si alloy, providing important insights into the nucleation and early-stage growth of Si nanowires; 4) the interfacial interaction between the Au-Si alloy and various facets of crystalline Si, such as (111), (211), (110), (110), which explains well the underlying reasons for the growth direction of Si nanowires; 5) the oxidation of the Au-Si alloy; and 6) the surface reconstruction and chemistry of Si nanowires with comparisons to planar Si surfaces. Outcomes from the thesis work contribute to: clarifying the atomic structure, energetics and chemical ordering of amorphous bulk Au-Si alloys, as well as their surfaces and interfaces; better understanding molecular mechanisms underlying the Aucatalyzed synthesis of Si nanowires; and identifying the surface reconstruction and chemistry of Si nanowires. The improved understanding can provide invaluable guidance on the rational design and fabrication of Si nanowire-based future electronic, chemical, and biological devices. This thesis work also offers a theoretical platform for studying metal alloy systems with various applications. / text

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Thesis (Ph. D.)--Murdoch University, 2007. / Thesis submitted to the Division of Arts. Includes bibliographical references (p. 202-204).

Published also as the author's inaugural dissertation, Munich, 1969. / Bibliography: p. [ix]-xiv.

Inaug.-diss. -- Heidelberg.