The primary study of this thesis is the experimental realization of the non-equilibrium dynamics of a quantum inverted pendulum as examined in the collective spin dynamics of a spin-1 Bose-Einstein condensate. In order to compare experimental results with the simulation past the low depletion limit, current simulation techniques needed to be extended to model atomic loss. These extensions show that traditional measurements of the system evolution (e.g. measuring the mean and standard deviation of the evolving quantity) were insufficient in capturing the quantum nature of the evolution. It became necessary to look at higher order moments and cumulants of the distributions in order to capture the quantum fluctuations. Extending the implications of the loss model further, it is possible that the system evolves in a way previously unpredicted. Spin-mixing from a hyperbolic fixed point in the phase space and low noise atom counting form the core of the experiment to measure the evolution of the distributions of the spin populations. The evolution of the system is also compared to its classical analogue, the momentum-shortened inverted pendulum. The other experimental study in this thesis is mapping the mean-field phase space. The mean-field phase space consists of different energy contours that are divided into both phase-winding trajectories and closed orbits. These two regions are divided by a separatrix whose orbit has infinite period. Coherent states can be created fairly accurately within the phase space and allowed to evolve freely. The nature of their subsequent evolution provides the shape of the phase space orbit at that initial condition. From this analysis a prediction of the nature of the entire phase space is possible.

Extrusion compounding addresses such problems as the non-homogeneity of the mixture and separation of fiber from the polymer during rotational molding, which consequently affect the mechanical and physical properties of the resulting composites. <p>Using triethoxyvinylsilane as chemical pre-treatment on flax fibers and linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) as polymer matrices, this study focused on the effects of flax fiber content (0%, 12.5% or 25%) and extrusion parameters such as barrel zone temperatures (75-110-120-130-140°C or 75-120-130-140-150°C) and screw speed (110 or 150 rpm) on the extrudate and composite properties (extrudate color, extrudate density, extrudate melt flow index, extrudate morphology, composite color, composite density, composite morphology, composite tensile strength and composite water absorption). <p>A mixture of chemically pre-treated flax fibers and powdered polyethylene matrices underwent extrusion compounding using a twin-screw extruder. The extrudates were then pelletized, ground, rotationally molded and cut into test specimens (composites). The mechanical and physical properties of both the extrudates and the composites from different treatments were then measured and compared. <p>Using multiple linear regression, models were generated to show quantitatively the significant effects of the process variables on the response variables. Finally, using response surface methodology and superposition surface methodology on the preceding data, the following optimum values for fiber content and extrusion parameters were determined: for LLDPE composites, fiber content = 6.25%, temperatures = 75-117.3-127.3-137.3-147.3°C, screw speed = 117.5 rpm; for HDPE composites, fiber content = 5.02%, temperatures = 75-118.1-128.1-138.1-148.1°C, screw speed = 125.56 rpm.

The rapid advancement of information technology and its integration with the manufacturing technology increased the necessity of consistent and coherent data flow in the chain of Computer Aided Design (CAD)-Computer aided Manufacturing (CAM)-Computer Numerical Control (CNC). To achieve this, ISO 10303 standard (STEP), developed by ISO, is seen as a solution since STEP is independent of the environment on which design data, manufacturing data or machining data produced. In this thesis, efficiency of NC-code generation, with the inclusion of process planning data, from a STEP based CAD data is investigated. For the investigation purposes, software responsible for both building the STEP based CAD data and generating related NC-code automatically is developed. Using this software, several parts are designed / generated NC-codes are verified via CNC simulators and some test parts are produced. STEP AP224 based feature modeler, developed specifically for 2- axis rotational part design, includes / feature library, feature modeler employing SW2007 via API for visualization and preprocessor responsible for generation of STEP file in neutral format, called STEP Part 21. The NC-code generator includes / postprocessor responsible for STEP Part 21 interpretation, CNC machine tool and cutting tool database and preprocessor responsible for NC-code generation.

In this study, a new vector form intrinsic finite element (VFIFE) for the plate is developed and applied to study the responses of a traditional plate member applied to engineering structures. The VFIFE method is a solution procedure for the mechanic problems by adopting the traditional co-rotational explicit finite element method developed by Belyschko and Hsieh (1973). Three different shape-functions including the simplest polynomial form shape-function (Poly), non-conforming area coordinate shape-function (BCIZ) and the conforming area coordinate shape-function (BCIZC) are utilized to simulate the displacement field of the plate. For a system with nonzero rigid-body displacement, the equilibrium will be difficult to achieve in the global coordinate system when the traditional finite element method is applied. By separating the rigid-body motions from the deformed motions, this problem can be easily taken care. In numerical examples, the accuracy and efficiency of this new developed vector form intrinsic finite element for plate simulation are also examined. It is found that compared to the analytical solution, the accuracy is excellent, while compared to traditional finite element method, the efficiency is also encouraging. This new VIFIFE plate element was also applied to the analysis for the sheet plate members in the harbor structures such as the sheep-pile wharf structural system. It was found that not only can the global behaviors of the pile be clearly observed but also local variations in deformations of the steel sheet are clearly shown.

Thesis (Ph. D.)--Florida State University, 2003. / Advisor: Dr. Peng Xiong, Florida State University, College of Arts and Sciences, Dept. of Physics. Title and description from dissertation home page (viewed Apr. 9, 2004). Includes bibliographical references.

This thesis is the result of the investigation and solution of a mechanicalproblem regarding flywheel malfunctions. A flywheel is, in short, a devicethat relies on a rotating object’s moment of inertia to store energy overshort time spans. This project is part of the development of a fourthflywheel prototype at the division for electricity at Uppsala university,which uses magnetic levitation to keep a hollow cylinder rotating at veryhigh speeds inside a vacuum chamber. Should the magnets fail however, orsome other error occur that leads to an uncontrolled state of rotation, thecylinder needs to be stabilized mechanically by a device usually referredto as ‘back-up bearing’. This contraption might, like an airbag of a car,never be used but needs to be included if an emergency occurs to protectother parts of the flywheel which would otherwise be destroyed by theunrestrained rotor. A theoretical pre-study was conducted to determine what challenges andrespective solutions the design of such a device would encounter, forexample the amount of energy in the rotor and possible ways to dissipate itin the event of a malfunction. The benefits and downsides of materials andmachine elements such as bearings were investigated in order to design aset of backup bearings. The modelling was done using SolidWorks, which wasalso used to conduct thermal and mechanical simulations on differentconcepts. MatLab was used for calculations, using formulae from themanufacturers and from different websites. The project concluded that the sheer energy of the flywheel at top speedpresents considerable thermodynamic difficulties. A solution capable ofhandling this was however achieved, albeit barely. Unfortunately onlysimulations and calculations confirm this result as no practicalexperiments could be conducted, therefore caution is advised in futureexperiments where the flywheel speed approaches maximum levels.

The Magnetorotational Instability (MRI) is believed to be the primary mechanism for angular momentum transfer in astrophysical accretion disks. This instability, which exists in ionized disks in the presence of weak magnetic fields, can either transfer angular momentum directly, or give rise to anomalous viscosity via non-linear turbulence. While many previous analytical treatments are concerned with the local theory of the MRI, when the length scale of rotation shear is comparable to the length scale of the most unstable modes, a global analysis is necessary. In this dissertation we investigate the global theory of the linear MRI. In particular, we show how rotation shear can localize global modes and how the global growth rates can differ signicantly from the local approximation in certain cases. Changes in the equilibrium density are considered. In addition, the effects of Hall Magnetohydrodynamics on the MRI are studied in both the local and global cases. / text

The United States Navy incorporates many different occupations to ensure it achieves its overall mission. These occupations are extremely diversified and present a wide spectrum of occupational exposures. Many of these exposures have been well studied and documented. However, shipboard pneumatic tool hand-arm vibration, (HAV) and how it relates to different body postures is an area of occupational exposure that has received little attention. The chief objective of this study was to assess whether there is a difference in hand-arm vibration levels, while working on one of two surface orientations (e.g., horizontal and vertical) among distinctly different pneumatic tools while cleaning or not cleaning. The design of the study evaluated three pneumatic tools cleaning both horizontal and vertical surfaces and the fourth tool only cleaning a horizontal surface. HAV levels were measured to identify the effect horizontal and vertical surface orientations had on the tool. Five subjects were used in the evaluation of the four tools by a random sequencing order. Each subject was required to hold the tool in an idle condition, an activated without cleaning condition, and an activated cleaning condition, (surface contact) for 20 seconds each. These conditions were evaluated in two different surface orientations; horizontal and vertical (except for the 4th tool). Each subject repeated each of the cleaning/not cleaning conditions three times for a total of 7 measurements per surface. The idle condition was only conducted one time for each tool and surface. The measurements were collected from a Quest, HAVPro instrument using an accelerometer on the pneumatic tool following ISO 5349-1:2001 and ISO 5349-2:2001 methods.A three-way ANOVA (subjects by tool, by condition, (cleaning vs. not cleaning) and tool vs. condition) with replicates (not including idle conditions) was conducted on the data. The analysis included the main effects and the interaction of tool and surface orientation. The subjects were treated as a blocking variable. All the main effects and the interaction were significant at p<0.0001, except for surface, p<0.6396. Surface orientation does not affect HAV levels in pneumatic tools.

Simple organometallic molecules, especially those with a single ligand, are the desired model systems to investigate the metal-ligand interactions. For such a molecule, a quantitative relationship between the geometry and the electronic configuration would be instructive to test the existing theories and to access more complicated systems as well. As a matter of fact, microwave spectroscopy could be the best approach to address this issue by measuring the pure rotational spectrum of a metal-containing molecule. By doing so, microwave spectroscopy can provide the most reliable bond lengths and bond angles for the molecule based on the rotational constants of a set of isotopologues. On the other hand, from the fine-structure and hyperfine-structure of the spectrum, microwave spectroscopy can also describe the electronic manifold, charge distribution and bonding nature of the molecule in a quantitative way.Fourier transform microwave spectrometers have been the most popular equipment to measure the pure rotational spectrum for three decades owing to the high resolution and super sensitivity. With the advances in digital electronics and the molecular production techniques, hyperfine structures of metal-containing molecules can be easily resolved even for the rare isotopologues in their nature abundance by this type of spectrometers.In this dissertation, molecules bearing metals in a wide range covering both the main group and transition metals were studied. By taking advantage of both the traditional and newly developed molecular production techniques in the gas phase (for example, metal pin-electrodes and discharged assisted laser ablation spectroscopy), we obtained spectra of molecules containing magnesium, aluminum, arsenic, copper and zinc. Our subjects include metal acetylides (MgCCH, AlCCH and CuCCH), metal dicarbides (CCAs), metal cyanides (CuCN, ZnCN) as well as other metal mono-ligand molecules. For the zinc metal, complexes with two simple ligands were also investigated, such as HZnCl and HZnCN. We strongly believe that researchers in different disciplines would benefit from our laboratory studies: theoretical chemists can use our experimental results for calibration; astrophysicists would interpret their telescope observations by matching our precisely measured frequencies; material scientists could find new functional materials by linking the bulky properties of certain materials with our spectroscopic results of the monomers.

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