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Polyimides by nature are highly resistive materials which exhibit exceptional thermal and chemical stabilities. Yet, there are a number of instances in which a polymeric material displaying low resistance and featuring similar physical, chemical, and thermal characteristics as polyimide would be desirable. Toward this goal, multilayered polyimide composite films have been produced through the homogeneous incorporation of copper salts and complexes into poly(amide acid) followed by thermal processing. In this way, highly anisotropic copper containing composite films have been obtained which feature a surface or near-surface layer of copper metal or copper oxide as the conductive medium. The surface resistivity of the composites is lowered up to ten orders of magnitude relative to unmodified polyimide films. However, in many cases, the discontinuity of the copper containing layer limits the attainment of near-theoretical resistivity. Hence, evaluation of the composites by a variety of analytical techniques have been used to develop structure-process-property relationships in order to optimize the electrical properties of these materials. The surface treatment of polymeric materials by glow discharge is known to improve their adhesive strength when in contact with a large number of other substances, be they polymeric, metallic, or ceramic in nature. Many efforts have been made to characterize this phenomenon, however in most instances, details concerning the interfacial structure and adhesion mechanism are not fully understood. The second part of this Dissertation describes the structure and chemistry occurring in the interfacial region between sputter-coated titanium metal, and both plasma pretreated and nonpretreated polyethylene terephthalate (PET) film. The effect of plasma pretreatment on nonmetallized PET is discussed as well. Upon application of a gaseous plasma, titanium/polyester adhesion increases dramatically following metallization compared to the nonpretreated analog. In order to relate this phenomenon to a physical and/or chemical change X-ray photoelectron spectroscopy, Auger electron spectroscopy, transmission electron microscopy, as well as, surface Fourier transform infrared spectrometry have been used to characterize both the surface and interfacial regions of these films. / Ph. D.

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Concrete filled steel hollow structural (CFS) sections are increasingly used to support large compressive loads in buildings, with the concrete infill and the steel tube working together to yield several benefits both at ambient temperature and during a fire. These members are now widely applied in the design of highly optimized multi-storey and high rise buildings where fire resistance ratings of two or more hours may be required. Whilst the response and design of these sections at ambient temperatures is reasonably well understood, their response in fire, and thus their fire resistance design, is less well established. Structural fire resistance design guidance is available but has been developed based on tests of predominantly short, concentrically-loaded, small-diameter columns in braced frames using normal strength concrete. The current prescriptive guidance is limited and the design of CFS columns is thus often based on a detailed performance based approach, which can be time consuming and expensive and which is generally not well supported by a deep understanding of CFS columns’ behaviour in real fires. This thesis aims to understand the fundamental thermal and mechanical factors at play within these sections so as to provide guidance on how to improve their design for fire resistance when applied either as unprotected or protected sections. A meta-analysis of available furnace test data is used to demonstrate that current guidance fails to capture the relevant mechanics and thus poorly predicts fire resistance. It is also demonstrated that the predictive abilities of the available design standards vary with physical characteristics of the CFS section such as shape and size. A factor which has been observed in furnace tests on CFS sections but which is not accounted for in available guidance is the formation of an air gap between the steel tube and the concrete core due to differential expansion; this affects their structural response in fire. The insulating effect of air gap formation has not previously been addressed in literature and an experimental program is presented to systematically assess the effects of a gap on the heat transfer through the section; showing that the presence of even a 1 mm gap is important. To explicitly assess the heat transfer response within both unprotected and fire protected (i.e. insulated) CFS sections, 34 large scale standard furnace tests were performed in partnership with an industry sponsor. Fourteen tests on large scale unloaded unprotected CFS sections are presented to assess current capability to predict the thermal response and to assess the effects of different sectional and material parameters on heating. New best practice thermal modelling guidance is suggested based on comparison between the models and observed temperatures from the tests. Twenty CFS specimens of varying size and shape, protected with different types and thicknesses of intumescent paint fire insulation, were also tested unloaded in a furnace to understand the thermal evolution within protected CFS sections and to develop design guidance to support application of intumescent coatings in performance based fire resistance design of CFS sections. These tests demonstrate that the intumescent coatings were far more effective than expected when applied to CFS sections, and that current methods of designing the coatings’ thickness are overly conservative. The reason for this appears to be that the calculation of effective section factor which is used in the prescription of intumescent coating thicknesses is based on the thermal response of unprotected CFS sections which display fundamentally different heating characteristics from protected sections due to the development of a thermal gradient in the concrete core. It is also demonstrated (by calculation supported by the testing presented herein) that the steel failure temperature (i.e. limiting temperature) of an unprotected CFS column in fire is significantly higher than one which is protected; procedures to determine the limiting temperature of protected sections are suggested. Finally, the residual strength of fire-exposed CFS columns is examined through structural testing of 19 of the 34 fire tested columns along with unheated control specimens. The results provide insights into the residual response of unprotected and protected CFS section exposed to fire, and demonstrate a reasonable ability to calculate their residual structural capacity. The work presented in this thesis has shed light on the ability of available guidance to rationally predict the thermal and structural response to fire of CFS columns, has improved the understanding of the thermal evolution within protected and unprotected CFS sections in fire, has provided best-practice guidance and material input parameters for both thermal and structural modelling of CFS sections, and has improved understanding of the residual capacity of CFS sections after a fire.

The study of acoustic resonance in fluid-filled piping systems with and without mean flow is important for the nuclear industry. For this industry, it is vital to understand the acoustic resonance in their systems; however, no comprehensive experimental benchmark data or accurate modeling tool exists for predicting such a phenomenon. The main goals of the current research are to create a new experimental data bank for the conditions not tested earlier using the configurations of straight lines and branches, and to evaluate the applicability of the linear wave solution using different damping methods and a computational fluid dynamic (CFD) code to simulate the acoustic resonance in fluid-filled piping systems. In this experimental study, data on resonant frequencies and resonant amplitudes are collected and analyzed for a frequency range of 20–500 Hz for straight and branched tubes by varying their wall thicknesses, materials, and branch configurations at different flow rates and outlet boundary conditions. To be closer to the nuclear industry medium, water is employed in our experiments, contrasting to the fact that most of the available experiments reported were with air at a much lower sonic velocity. I consider here, in particular, measurements at the end of closed branches, upstream, downstream, and at different locations of the main line, as well as the interactions of different sonic velocities along the main pipes. A small diameter is chosen for the branched experiments since the decrease in the width of the main line and the branches has a pronounced effect on the resonant amplitudes due to an increased interaction among the unsteady shear layers forming across the side branches. The experimental results show that there is a strong effect of turbulent flow, wall material, and wall thickness on resonant amplitudes at frequencies above ∼250 Hz. Numerical investigations are performed solving the one-dimensional (1D) linear wave equation with constant and frequency-dependent damping terms and a CFD code. Employing frequency-dependent damping methodologies shows improvement in terms of resonant amplitude prediction over constant volumetric drag method. Comparing the 1D and CFD results shows that the CFD solution yields better predictions. / February 2017

A thesis on the study of the frequency response of a pneumatic system designed to provide pulsed flow for flow control applications is presented. The system consists of a high pressure air source, a high-frequency solenoid valve, a length of tube and a minor loss. The experiment mimics the pneumatic drive for our Coanda-Assisted Spray Manipulation actuator and applies to many flow control applications involving pulsed flow. Square wave signals of various frequency are fed to the solenoid valve. The flow at the exit of the system is measured with a single hot wire and compared to steady flow through the same geometry. The effect of the inlet pressure, tube length and the size of the minor loss is evaluated. These data are modeled using a Transmission Matrix Model. (60 pages)

A new wall construction technique utilizing concrete filled PVC tubes, adobe, polyethylene terephthalate (PET) plastic bottles and cabling was designed, analyzed and implemented. The system was designed as an alternative to traditional earthen buildings in Honduras that are vulnerable to hurricane winds and seismic activity. Six prototype panels were constructed at the Alternative Village located at the University of Manitoba to evaluate the wall system for racking and transverse load capacity. A kitchen was then constructed at an elementary school in western Honduras. / October 2015

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references. Also available on the World Wide Web.

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