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This thesis is concerned with the development and experimental analysis of a resonant gyroscope. Initially, this involved the development of a fabrication process suitable for the construction of metallic microstructures, employing a combination of nickel electroforming and sacrificial layer techniques to realise free-standing and self-supporting mechanical elements. This was undertaken and achieved. Simple beam elements of typically 2.7mm x 1mm x 40µm dimensions have been constructed and subject to analysis using laser doppler interferometry. This analysis tool was used to implement a fill modal analysis in order to experimentally derive dynamic parameters. The characteristic resonance frequencies of these cantilevers have been measured, with 3.14kHz, 23.79kHz, 37.94kHz and 71.22kHz being the typical frequencies of the first four resonant modes. Q-factors of 912, 532, 1490 and 752 have been measured for these modes respectively at 0.01mbar ambient pressure. Additionally the mode shapes of each resonance was derived experimentally and found to be in excellent agreement with finite element predictions. A 4mm nickel ring gyroscope structure has been constructed and analysed using both optical analysis tools and electrical techniques. Using laser doppler interferometry the first four out-of-plane modes of the ring structure were found to be typically 9.893 kHz, 11.349 kHz, 11.418 kHz and 13.904 kHz with respective Q-factors of 1151, 1659, 1573 and 1407 at 0.01 mbar ambient pressure. Although electrical measurements were found to be obscured through cross coupling between drive and detection circuitry, the in-plane operational modes of the gyroscope were sucessfully determined. The Cos2Ө and Sin2Ө operational modes were measured at 36.141 kHz and 36.346 kHz, highlighting a frequency split of 205kHz. Again all experimentally derived modal parameters were in good agreement with finite element predictions. Furthermore, using the analysis model, the angular resolution of the gyroscope has been predicted to be approximately 4.75º/s.

This contribution explores the applicability of nickel-based metallic foams as active electrodes and as electrocatalyst support materials. A comprehensive characterization of Ni and multi-component Ni-based foams is presented and includes the analysis of their structural, chemical, and electrochemical properties. Several materials and surface science techniques as well as electrochemical methods are used to examine the structural characteristics, surface morphology, and surface-chemical composition of these materials. X-ray photoelectron spectroscopy is employed to analyze the surface and near-surface chemical composition. The specific and electrochemically active surface areas (As, Aecsa) are determined using cyclic voltammetry (CV). The foams exhibit structural robustness typical of bulk materials and they have large As, in the 200 – 600 cm2 g–1 range. In addition, they are dual-porosity materials and possess both macro and meso pores. Nickel foam electrodes are applied as electrocatalysts for the oxidation of isopropanol. The process is studied under well-defined experimental conditions using cyclic voltammetry. The outcome of these experiments demonstrates that isopropanol oxidation requires the presence of -NiOOH on the Ni foam electrode. This surface oxide is generated at potentials near the potential of the isopropanol oxidation; however, the two processes do not occur exactly at the same potentials. The Ni foam anodes sustain a current density of ca. 2.6 mA cm–2 throughout an electrolysis time of up to 600 minutes without significant loss of electrocatalytic activity. Isopropanol is converted to acetone at a rate of ca. 5.6 mM per hour. The applicability of Ni foams as support materials for Pt is investigated. Platinum particles are deposited on Ni foam in low loading amounts via the chemical reduction of Pt2+ and Pt4+ originating from aqueous Pt salt solutions. The resulting Pt / Ni foams are characterized using electrochemical, analytical, and materials analysis techniques, including SEM to examine the morphology of the deposited material, CV to evaluate the Aecsa of the deposited Pt, and inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the mass of deposited Pt. The Pt / Ni foams are applied as electrocatalysts for hydrogen evolution, hydrogen reduction, oxygen evolution, and oxygen reduction reactions in alkaline electrolyte. / Thesis (Ph.D, Chemistry) -- Queen's University, 2013-12-06 13:28:17.471

The thesis describes an electrochemical investigation of different types of nickel electrode used in nickel-cadmium cells, which are available commercially or currently under development. Impedance spectroscopy has been used to determine the electrochemical characteristics of these electrodes. The electrochemistry of the nickel electrodes was modelled by the electrical analogue method. Allowance was made within the model for porosity and adsorption effects. Component values were initially estimated by graphical techniques and the computer fitting procedure was then completed by an iterative process to provide kinetic parameters which were used to compare and contrast the characteristics of the nickel sintered, pocket and plastic bonded electrodes. The technological target of this work was establish a possible method by which the residual capacity remaining within nickel-cadmium cells could be determined. The kinetic parameters generated by the electrical analogue technique have provided data on which to base a measurement for the prediction of the state of charge in nickel-cadmium cells.