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The primary purpose of this research is to investigate non-linear and chaotic behaviour of water in a pipeline at the transition region from laminar to turbulent flow. Turbulence was generated in the flow by the use of an orifice plate which generated coherent vortices and subsequent break-down into turbulence, downstream of the orifice. The flow regime was pulsatile. This was decided specifically to obtain better control of the experimental apparatus, better control of the frequency of vortices shedding from the orifice, and because of its wider range of practical applications discussed in section 1.3. The mechanism of vortex breakdown has been addressed many times over the past century. The process by which vortices interact and degenerate is essentially non- inear. New techniques from the field of non-linear dynamics have emerged which can yield some quantitative information about the complexity of non-linear phenomena. This thesis aims to test some of these techniques, together with more traditional methods, on the experimental time series data obtained from axisymmetric vortex breakdown of a pulsed flow at a pipe orifice. An experimental rig was designed and constructed in the Civil Engineering Department, at the University of Glasgow, to produce, accurately controllable, pulsed flows within a pipe system at an orifice plate. The apparatus was designed to allow a range of parameters to be varied over the course of the investigation. Computer algorithms were written by the author to analyse the resulting data, obtained from Laser Doppler Anemometry readings. Flow visualisation techniques were also used to give a qualitative understanding of the system. Evidence was found for the development of initially axisymmetric pulsed vortex flows to a relatively low dimensional chaotic state prior to breaking down to a more complex turbulent state. The flow complexity was probed by investigating the dynamics of phase space attractors reconstructed from time series taken at various spatial locations within the developing flow field. The two techniques used for this were the Grassberger- Procaccia dimension and the Lyapunov exponent. Reconstruction of the attractors was performed using the minimum mutual information function. The flow complexity was used in conjunction with Turbulent Intensitites within the flow and the development of the flow velocity profile, to provide a comprehensive picture of the flow field development for pulsed vortex flows. In addition, the techniques from the field of non-linear dynamics were thoroughly tested in the experimental environment. The problem of noise, and its effect on the results produced has been analysed in detail.

Abstract: An examination as to what adaptations were advantageous in survival and growth of Luzula confusa at Cape Abunathy.

This thesis examines attitudes toward international affairs held by students and staff at the University of Edinburgh between 1914 and 1939, particularly those relating to the issues of war and peace. Specific ideological areas to be looked at include religious influences, nationalism and imperialism, racial concepts, health, fitness and eugenics, and Marxism. Primary sources made use of throughout include the private papers and publications of officials and teaching staff at the university, newspaper letters and reports, University Court, Senatus, Faculty and other committee papers and minutes, official University publications and course text books, and student publications, society minutes and debating records. In the main body of the thesis the relevant positions of the student body and University official and staff are looked at separately and a generally chronological approach followed, with the overall period divided up into World War One, the 1920s, and the 1930s respectively. The conclusion seeks to evaluate the reasons why both students and staff offered up a generally vigorous support for Britain’s war efforts in both 1914 and 1939, this in spite of the widespread popularity of pacifistic ideas throughout the period covered.

A study was conducted to investigate the use of time-frequency methods to predict the outcome of defibrillation for patients presenting with ventricular fibrillation. Both wavelet transform and short time Fourier transform methods were applied to extract characteristic features from a data base of pre-shock signals. A Bayes classifier was developed for classifying between those outcomes where a return of spontaneous circulation (ROSC) was achieved and those where it was not (NOROSC). Probability distribution functions were estimated using multidimensional histogram and Gaussian kernel smoothing techniques. Cross validation was employed to improve the confidence of results. Three formats of feature sets including the original feature sets, normalised feature sets, and principal component analysis (PCA) feature sets were used in the classification. The optimal pre-shock length and temporal location were investigated. In related studies the a posterior probability function was employed to indicate the probability of successful shock (PROSC) and the effect of wavelet central frequency was also studied. The best classification performance for the original, normalised, and PCA feature sets were 58±2% specificity at 90±4% sensitivity, 59±3% specificity at 90±4% sensitivity, and 56±3% specificity at 92±4% sensitivity respectively. Overall it was found that the analysis employing time-frequency-based methods improved the performance of shock outcome prediction when compared to currently available alternative methods.

The primary purpose of this work was to study the morphological change of river-bed sediment surfaces over time using wavelet transform analysis techniques. The wavelet transform is a rapidly developing area of applied mathematics in both science and engineering. As it allows for interrogation of the spectral made up of local signal features, it has superior performance compared to the traditionally used Fourier transform which provides only signal averaged spectral information. The main study of this thesis includes the analysis of both synthetically generated sediment surfaces and laboratory experimental sediment bed-surface data. This was undertaken using two-dimensional wavelet transform techniques based on both the discrete and the stationary wavelet transforms. A comprehensive data-base of surface scans from experimental river-bed sediment surfaces topographies were included in the study. A novel wavelet-based characterisation measure - the form size distribution ifsd) - was developed to quantify the global characteristics of the sediment data. The fsd is based on the distribution of wavelet-based scale-dependent energies. It is argued that this measure will potentially be more useful than the traditionally used particle size distribution (psd), as it is the morphology of the surface rather than the individual particle sizes that affects the near bed flow regime and hence bed friction characteristics. Amplitude and scale dependent thresholding techniques were then studied. It was found that these thresholding techniques could be used to: (1) extract the overall surface structure, and (2) enhance dominant grains and formations of dominant grains within the surfaces. It is shown that assessment of the surface data-sets post-thresholding may allow for the detection of structural changes over time.