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In this thesis we study various dissipative processes that are associated with the flow of an atomic Bose-Einstein condensate at zero temperature. In particular, we investigate the effect of a weak correlated disorder potential on the collective dipole motion of a harmonically-confined elongated condensate. By using an extension of the Harmonic Potential Theorem, we demonstrate that the dynamics of the system can be described equivalently in terms of a disorder potential oscillating relative to a stationary condensate. This latter point of view allows the application of linear response theory to determine the drag force experienced by the condensate and to evaluate the damping rate of the centre of mass oscillation. The density response function for the elongated condensate is determined with a new local density approximation that takes into account the tight radial confinement of the atomic cloud. Our linear response theory reveals the detailed dependence of the damping rate on various system parameters. A comparison with available experimental data is only partially successful and points to the need for additional experiments. In addition to disorder induced dissipation, we also consider a variety of other problems that can be addressed by means of linear response theory. For example, we study momentum transferred to a condensate by a Bragg pulse and the energy absorption of a gas in an optical lattice that is parametrically modulated in different ways. All of these applications demonstrate the utility of linear response theory in describing the dynamics of Bose-condensed systems which are subjected to weak perturbations. / Thesis (Ph.D, Physics, Engineering Physics and Astronomy) -- Queen's University, 2013-04-26 10:54:11.915

Incombustibility is one important advantage of the sheet steel sheathed shear wall over wood panel sheathed shear wall. Compared to shear wall sheathed with plywood and OSB panel, shear wall sheathed with flat sheet steel behaved lower shear strength. Although shear wall sheathed with corrugated sheet steel exhibited high nominal strength and high stiffness, the shear wall usually behaved lower ductility resulting from brittle failure at the connection between the sheathing to frames. This research is aimed at developing modifications on the corrugated sheathing to improve the ductility of the shear wall as well as derive practical response modification factor by establishing correct relationship between ductility factor ? and response modification factor R. Totally 21 monotonic and cyclic full-scale shear wall tests were conducted during the winter break in 2012 by the author in NUCONSTEEL Materials Testing Laboratory in the University of North Texas. The research investigated nineteen 8 ft. × 4 ft. shear walls with 68 mil frames and 27 mil corrugation sheet steel in 11 configurations and two more shear walls sheathed with 6/17-in.OSB and 15/32-in. plywood respectively for comparison. The shear walls, which were in some special cutting arrangement patterns, performed better under lateral load conditions according to the behavior of ductility and shear strength and could be used as lateral system in construction.

The concept of Strategic Culture was developed during the Cold War years as a tool to analyse the nuclear policies of the Soviet Union and the United States, in an effort to assess the likelihood of their utilising their nuclear capabilities. Strategic Culture provides a useful lens through which we may understand the context, outlook and behaviour of states, shedding light on the way they perceive the international community and their role within it. As the Cold War came to an end, the focus of Strategic Culture literature shifted from the nuclear bipolarity that characterised U.S.-Soviet relations, to focus on other states and issue areas that dominated the international agenda within the New World Order. This thesis seeks to return to the original tenets of Strategic Culture, bringing attention back to the initial remits of this area of study, that is, the nuclear strategic cultures of the U.S.A. and Russia. Further to identifying the strategic cultures of the United States and Russia, this research questions whether these have been impacted by the change in international order brought on by the end of the Cold War. This work will also question whether nuclear weapons contorted their respective strategic cultures, or whether their strategic cultures were insulated from the impact of nuclear weapons. It will also assess whether the differences in strategic cultures have brought about differences in nuclear policy.

The Copper Development Association (CDA) has identified over 450 copper alloys registered with the U.S. Environmental Protection Agency (EPA) as antimicrobial. With growing antibiotic resistance, there is a need for copper coatings with increased antimicrobial capability. Cold spray is a high velocity, high deposition rate process that forms dense coatings with little to no oxides or inclusions. It is possible that this process contributes to the increased antimicrobial capability of copper cold spray coatings as compared to other additive processes. The focus of this effort is to understand the effects of powder production and cold spray process parameters on copper cold spray coatings in order to optimize antimicrobial properties. Specifically, this work looks at the differences in conventional and nanomaterial copper cold spray coatings. Materials characterization and test methods show differences in adhesion, microstructure, corrosion, mechanical properties, and surface topography. Materials data is compared against Abaqus FEA software model outputs, and antimicrobial efficacy test data, based on the EPA approved procedure, is used to support materials observations and modelling outputs.

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

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Senator Warren Robison Austin (R-VT) was appointed by President Harry S. Truman to be the US Representative to the United Nations in June 1946. While a member of the US Senate, Austin had been a great advocate for internationalism and the United Nations. His tenure as Representative lasted until January 1953. The growing pains of the new organization were complicated by myriad contentious problems, not the least of which was the dawning of the Cold War. Austin was caught between the Soviet delegation, who were bent on opposing virtually all US initiatives at the UN, and members of the Truman Administration who were adamantly anti-communist/anti-Soviet. This thesis examines the role that anti-communism played in establishing an atmosphere of distrust leading, at least partly, to the Cold War; and Austin’s role at the United Nations as regards three representative issues that confronted the international organization during his tenure. The first issue was how the Soviets and the Western Powers disagreed over the question of unanimity of the permanent five members in the Security Council. Next, I will show how irreconcilable differences between the United States and the Soviets thwarted the functioning of the Atomic Energy Commission of the Security Council. Lastly, the Korean War is examined as the first use of a military response by the United Nations to international aggression. Austin dutifully represented the administration at the United Nations, but often expressed his own less confrontational views in meetings, speeches outside the UN, and in letters to friends and loved ones. He held the United Nations to be a positive force for peace, while other members of the administration were stridently anti-Soviet and found the United Nations to be the perfect ideological battleground while acting unilaterally outside the organization. I will show how Austin had an idealistic view of the United Nations and maintained that it was the best vehicle for the maintenance of peace. Also how he was, initially, more even-handed in dealing with the Soviet delegation than his overseers in the Truman administration. He eventually grew weary of Soviet tactics and their alleged aggression in Korea leading him to harden his outlook.

Graduation date: 1994

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