This thesis presents the results of developing road pavement deterioration models for the State Highway network in New Zealand pavement deterioration models are an integral part of pavement management systems, which are used to forecast long-term maintenance needs and funding requirements on a road network. As part of this research, a Long-term Pavement Performance (LTPP) programme has been established on 63 sections of the State Highways. These sections are representative of typical road sections and climatic conditions on New Zealand roads. Data collection on these sections is undertaken on an annual basis and consists of high accuracy manual measurements. These measurements include road roughness, rutting, visual defect identification and strength testing with a Falling Weight Deflectometer. Based on the LTPP data, new model formats for New Zealand conditions were developed including a crack initiation model and a three-stage rut progression model. The rut progression model consists of three stages, initial densification, stable rut growth and a probabilistic model to predict accelerated rut progression. The continuous probabilistic model developed predicts the initiation of pavement failure events such as crack initiation and accelerated rutting. It has been found that this model type has a strong agreement with actual pavement behaviour as it recognises a distribution of failure on roads rather than failure occurring at an particular point in time, namely, a year. The modelling of rut progression in the three stages including, initial densification, stable rut progression and accelerated rutting has resulted in a significant increased understanding of this defect, especially for thin flexible chip seal pavements. It has been established that the in-service performance of these pavements is relatively predictable. However, incorporating both the in-service performance and the failure of pavements into one model was unrealistic. Therefore, by having the different stages of rutting, resulted into a more accurate forecasting of this defect. Although this research has covered the two priority pavement models including cracking and rutting prediction, it has established the model framework for other pavement models to be developed. As more data become available, further work can be undertaken to refine the models and to extend the research into the performance of alternative construction materials.

An efficient finite element method is developed to model the spreading of excitation in ventricular myocardium by treating the thin region of rapidly depolarizing tissue as a propagating wavefront. The model is used to investigate the excitation sequence in the full canine ventricular myocardium. The solution to an eikonal–curvature equation for excitation time is shown to satisfy a reaction–diffusion equation for the bidomain myocardial model at the wavefront, while the solution to an eikonal–diffusion equation approximately satisfies the reaction–diffusion equation in the vicinity of the wavefront. The features of these two eikonal equations are discussed. A Petrov–Galerkin finite element method with cubic Hermite elements is developed to solve the eikonal–diffusion equation. The oscillatory errors seen when using the Galerkin weighted residual method with high mesh Péclet numbers are avoided by supplementing the Galerkin weights with C⁰ continuous functions based on derivatives of the interpolation functions. The ratio of the Galerkin and supplementary weights is a function of the Péclet number such that, for one-dimensional propagation, the error in the solution is within a small constant factor of the optimal error achievable in the trial space. An additional noinflow boundary term is developed to prevent spurious excitation initiating on the boundary. The need for discretization in time is avoided by using a continuation method to gradually introduce the non-linear term of the governing equation. A small amount of artificial diffusion is sometimes necessary. Simulations of excitation are performed using a model of the anisotropic canine ventricular myocardium with 23.55 degrees of freedom for the dependent variable, and results are compared with reported experimental observations. When it was assumed that Purkinje fibres influence propagation only on the endocardial surface, excitation of the entire myocardium was completed in 56 ms. Altering material parameters to represent penetration of the Purkinje fibres beneath the left endocardial surface reduced the completion time to 48 ms. Modelling the effects of the laminar structure of myocardium by reducing the propagation speed by 40% in the direction normal to the layers delayed completion of excitation by only 4%.

The deployment of third generation (3G) cellular systems is resulting in a transition from cellular systems that predominantly carry constant-bit-rate (CBR) voice traffic to multi-service packet based systems that predominantly carry variable-bit-rate (VBR) traffic. With 3G DS-CDMA cellular systems there is a direct relationship between user traffic and propagation dependent performance as additional traffic causes increased system interference. This thesis investigates the impact of VBR traffic on the propagation dependent performance of DS-CDMA cellular systems that utilise frame-by-frame dynamic resource allocation on the radio channel. A DS-CDMA cellular system model is developed and the downlink performance of both outdoor macro-cellular and indoor pico-cellular systems is evaluated with a variety of traffic types. Both traffic scheduling performance and propagation dependent performance are evaluated as the two are inter-linked. Scenarios are identified where propagation dependent performance is sensitive to the statistical properties of the user traffic streams and it is shown that a significant performance difference potentially exists between different traffic types when the number of users per cell is low. When a significant performance difference does exist, burstier more variable traffic generally results in superior propagation dependent performance. The base transceiver station (BTS) transmitter power mean and variance provides a good indication of the level of propagation dependent performance regardless of the specific traffic type. Traffic scheduling policies that deliberately reduce the variability of user traffic streams are considered and in terms of propagation dependent performance these are shown to have a minimal impact on the performance difference between different traffic types. The implications of VBR traffic on DS-CDMA cellular system design are outlined and it is shown that VBR traffic can be approximated as CBR traffic in many scenarios and this is a convenient approximation as it simplifies system design and detailed traffic models do not need to be developed.

This investigation presents research on the characteristic properties of Nylon66 and poly(ethylene naphthalate) (Ny66/PEN), and poly(butylene terephthalate) and poly(ethylene naphthalate) (PBT/PEN) blends with several weight compositions made by melt blending, by the use of 13C and 1H Nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Scanning electron microscopy (SEM), Differential scanning calorimetry (DSC) and Dynamic mechanical thermal analysis (DMTA), X-ray diffraction (X-RD), tensile, impact and stress relaxation tests. Ny66/PEN blends including several additives do not improve the miscibility of the constituent polymers and show lower tensile strength than those of homopolymers. However, PBT/PEN blends reveal improved tensile strengths of the blends between the ROM and MROM predictions lines with more than 50 % volume fraction of PEN. On the other hand, NMR spectra show no evidence of interchange reaction in both Ny66/PEN and PBT/PEN blends. SEM micrographs of fracture surfaces in PBT/PEN blends reveal a very small (sub-micron) domain size in contrast to large domains in Ny66/PEN blends, which indicates partial miscibility of PBT and PEN. DSC and DMTA demonstrate partial miscibility of PBT/PEN blends by the change of Tgs of each component according to the weight proportions of the constituent polymers. Stress relaxation tests for the specimens of PBT/PEN blends and the homopolymers, using the Taguchi method of experimental design, determine that the most significant factor is the temperature, followed by PEN content and then the initial stress, and interaction effects between factors are insignificant. To fit the relaxation curves of the PBT/PEN blends and the homopolymers at different temperatures, PEN contents and initial stresses, four different equations have been used. The coefficients of the equation that fit best are used to predict the relaxation behaviour of PBT/PEN blends at a temperature between 30C and 60C, and at the initial stresses of 7 MPa.

Medical imaging is an essential tool for improving the diagnoses, understanding and treatment of a large variety of diseases. Over the last century technology has advanced from the discovery of x-rays to a variety of 3D imaging tools such as magnetic resonance imaging, computed tomography, positron emission tomography and ultrasonography. As a consequence the size and complexity of medical data sets has increased tremendously making it ever more difficult to understand, analyze, compare and communicate this data. Visualization is an attempt to simplify these tasks according to the motto "An image says more than a thousand words". This thesis introduces a toolkit for visualizing biomedical data sets with a particular emphasis on second-order tensors, which are mathematically described by matrices and can be used to express complex tissue properties such as material de-formation and water diffusion. The toolkit has a modular design which facilitates the comparison and exploration of multiple data sets. A novel field data structure allows the interactive creation of new measures and boolean filters are introduced as a universal visualization tool. Various new visualization methods are presented including new colour mapping techniques, ellipsoid-based textures and a line integral convolution texture for visualizing tensor fields. To motivate the design and to assist in the use of the toolkit, guidelines for creating effective visualizations are derived by using perceptual concepts from cognitive science. A new classification for visual attributes according to representational accuracy, perceptual dimension and spatial requirements is presented and the results are used to derive values for the information content and information density of each attribute. A review and a classification of visualization icons completes the theoretical background. The thesis concludes with two case studies. In the first case study the toolkit is used to visualize the strain tensor field in a healthy and a diseased human left ventricle. New insight into the cardiac mechanics is obtained by applying and modifying techniques traditionally used in solid mechanics and computational fluid dynamics. The second case study explores ways to obtain in vivo information of the brain anatomy by visualizing and systematically exploring Diffusion Tensor Imaging (DTI) data. Three new techniques for the visualization of DTI data are presented: Barycentric colour maps allow an integrated view of different types of diffusion anisotropy. Ellipsoid-based textures and Anisotropy Modulated Line Integral Convolution create images segmented by tissue type and incorporating a texture representing the 3D orientation of nerve fibers. The effectiveness of the exploration approach and the new visualization techniques are demonstrated by identifying various anatomical structures and features from a diffusion tensor data set of a healthy brain.

It is crucial to understand the fundamental mechanisms of cleaning milk protein fouling to optimise Cleaning-in-place (CIP) process. Using Whey Protein Concentrate (WPC) gel as a model material and a rapid ultraviolet (UV) spectrophotometry, a comprehensive laboratory study on the cleaning of the WPC gel deposits from hard surface with alkaline cleaning solutions has been conducted. The kinetics of the cleaning process has been established and mathematical models have been developed in order to elucidate the influences of various parameters on cleaning process. This study has provided sound evidence that whey protein concentrate gel is a reliable simulation of the whey protein fouling deposits used in most milk protein fouling and cleaning studies. Based on treating denatured whey protein gels as biopolymers, a chemical reaction controlled polymer dissolution cleaning mechanism has been proposed. The polymer dissolution plays a major role of removing proteinaceous deposits when treated with alkaline solutions under the flow conditions tested. Similar to the diffusion of cleaning chemicals and chemical reactions, the reptation (induction) is also one of essential steps for the dissolution of WPC gels in alkaline solutions. The disengagement of intermediate reaction products (altered protein molecules) from a gel-solution interface and subsequent mass transfer of these reaction products to the bulk cleaning solutions are the rate-limiting steps for the cleaning process. The typical dissolution cleaning rate curve of WPC gels in alkaline solutions includes swelling, uniform and decay cleaning stages. This study on cleaning kinetics shows that increasing the cleaning temperature can improve the cleaning efficiency. The apparent activation energy for these three stages is 32.6, 40.5, and 38.3 kJ/mol, respectively, which is in agreement with previous research works. Increasing flow velocity enhances the cleaning process. However, this effect could be reduced when and the cleaning process gradually changes from a mass transfer-controlled process to a disengagement-controlled process, where the flow velocity is very high. The introduction of the hydrolysis, β-elimination reactions and some competing chemical reactions have highlighted the complex of chemical reactions involved in cleaning of proteinaceous fouling using alkaline solutions. The changes in molecular mass distribution and SH content of WPC gel dissolved at various temperatures observed has confirmed the assumption that all these chemical reactions are temperature dependent. The investigation on the swelling, microstructural and mechanical properties of WPC gels treated with alkaline solutions also illustrates the concentration dependency of these chemical reactions. The mechanical property studies demonstrate that the chemical treatment could make WPC gel weaker and easier to be destroyed. However, the relationship between the mechanical properties and the cleaning process needs to be further studied. Based on the polymer dissolution and mass transfer theory, a mathematical model of chemical cleaning has been proposed. Various parameters, such as tr (reptation time), Rm, (constant cleaning rate), mc, (the critical mass), ξ (rate constant in swelling stage), kA (rate constant in decay stage) and Ψ (a dimensionless parameter) have been used to characterise the whole cleaning process. Among the parameters used in the cleaning model, the constant cleaning rate (Rm) is the most important one and determines the overall efficiency of a cleaning process, which has been further predicted and expressed as a product of mass transfer coefficient and solubility of disengaged protein molecules. The successful model formulations for the cleaning rate and cleaning time under various operation conditions are a good outcome of the rational mechanisms proposed for the removal of proteinaceous fouling. This research has provided a good foundation for further fundamental research in this area and for optimising the cleaning processes.

Coronary blood flow through the ventricular contraction cycle has been investigated in this thesis using an anatomically accurate computational model. Using Strahler ordered morphological data and an avoidance algorithm a three dimensional finite element model has been constructed of the largest six generations of the coronary arterial network within an anatomically accurate finite element model of the left and right ventricles. Segment radii, lengths and connectivity are consistent with the literature, local network branch angles are consistent with the principle of minimum shear stress at bifurcations, and an even spatial distribution of vessel segments throughout the myocardium has been achieved. A finite difference collocation grid has been generated on the coronary finite element mesh. The Navier Stokes equations governing blood flow through elastic vessels have been reduced to one dimension and are solved on this finite difference grid using the two step Lax Wendroff method. Blood flows at bifurcations are calculated using an iterative method ensuring conservation of mass and momentum. The microcirculation networks are modelled using a lumped parameter model incorporating the nonlinear variation of resistance and compliance with pressure by fitting results from published anatomical data. The venous network is assumed to parallel the generated arterial model. The calculated blood flow through the network model demonstrates physiological pressure drops, flow rates and a regional distribution within the ventricular geometry consistent with experimental data. The intramyocardial pressure (IMP) exerted on the coronary vasculature during contraction is calculated from quasi-static solutions of the equations of finite deformation applied to the ventricular model with a nonlinear anisotropic constitutive law. IMP is found to vary approximately linearly between ventricular pressure at the endocardium and atmospheric pressure at the epicardium. IMP and vessel stretch are included in the transmural pressure radius relationship to model the effect of myocardial deformation on coronary flow. The calculated coronary blood flow through the contraction cycle shows that arterial flow is predominantly diastolic while venous flow is significantly increased during systole. Calculated time varying velocity profiles in the large epicardial vessels compare well with published experimental results. Regionally averaged velocities in small vessels show that arterial inflow is most significantly impeded at the left ventricular endocardium. Furthermore, the large time constant associated with the capillary and venule networks limits the filling of these vessels during diastole particularly at the endocardium. An increase in heart rate, modelled by reducing the time for diastole causes an increase in small vessel epicardial blood flow and a decrease in blood flow through small vessels within the myocardium. The decrease in flow is most pronounced at the left ventricular endocardium.

After introducing the subject of curvilinear flow, particularly in the context of meandering natural channels, this thesis then describes the three conventional models for unsteady flow in open channels, namely kinematic, diffusion and dynamic. These descriptions are in terms of the straight channel de Saint-Venant equations. The discussion also considers some aspects of the diffusion model which raise questions as to the appropriateness of the usual engineering approach to this model. As to date, these models treat curvature cursorily, if at all, the models are then expanded to incorporate curvature in a more systematic manner. This is done by deriving the de Saint-Venant equations in terms of curvilinear coordinates. The models are then presented in terms of the curvilinear mass-conservation and various forms of the curvilinear momentum equation. The new models are found to be expressed by equations of the form 'linear model + curvilinear correction' thus allowing the engineer to estimate the size of any curvature effect. The derived dynamic model is compared with a laboratory study, and the results indicate that the new curvilinear model is a reasonable description of dam-break flow. Subsequent calculations, based on field data, of the celerity of the dynamic wave illustrate how big the corrections can be.

This dissertation introduces the Artificial Computer Expert (ACE), a system designed to assist non-computer skilled personnel utilise complex computer software through the use of artificial intelligence in the creation, selection and execution of programs. The system comprises three parts: 1. A graphical interface and conceptual framework which allows an expert to define the structure of his knowledge relating to his field. 2. A compiler to work through such a structure, forming partial solution paths which indicate the relationships that exist in the structure. 3. An interpreter to run through the solution process, joining together the partial solution paths and creating instances of data files as required in order to reach the overall goal. The ACE system is presented in the context of an industrial application, demonstrating how it may be used to form sawmill cutting patterns (which indicate how lumber is to be milled from a set of logs). This application belongs to a class of scheduling problems known as ‘cutting stock problems’, which for anything other than small or simple cases typically require the presence of an on-site scheduling expert. The application developed produces acceptable cutting patterns without the need for such a scheduling expert, using the same software tools currently used by mill management to plan their production. / Whole document restricted, but available by request, use the feedback form to request access.

Diffuser Augmented Wind Turbines (DAWTs) are one of many concepts to have been proposed to reduce the cost of renewable energy. As the most commercially viable, they have been the focus of numerous theoretical, computational, and experimental investigations. Although intimated in these studies to be able to augment the power output of a wind turbine, the extent of this power increase, or augmentation, the factors influencing DAWT performance, the optimal geometric form and their economical benefit remained unanswered. It is these issues that have been addressed in this investigation. In reviewing historic investigations on DAWTs it has been identified that excessive wind tunnel blockage, inappropriate measurement technique, varied definitions of augmentation, and the inclusion of predicted performance based on incorrect assumptions have in general led to the overstatement of DAWT performance in those studies. In reassessing the performance of the most advanced of those DAWT designs, Grumman's DAWT 45, it has been calculated that the actual performance figures for the 2.62 exit-area-ratio and 0.488 length-to-diameter ratio DAWT were an available augmentation of 2.02, a shaft augmentation of 0.64 and a diffuser efficiency of 56%. By contrast, the development of the Mo multi-slotted DAWT in this investigation has yielded a design whose shaft augmentation of 1.38 was achieved by a diffuser with exit-area-ratio of only 2.22 and overall length-to-diameter ratio of 0.35. Such performance improvement has been obtained by gaining both an understanding of the flow characteristics of DAWTs and the geometric influences. More specifically it has been shown that: the velocity across the blade-plane is greater than the free-stream velocity and increases towards the rotor periphery; that the rotor thrust or disc loading impacts upon diffuser performance by altering the flow behaviour through it; and that DAWTs are able to maintain an exit pressure coefficient more negative than that attainable by a conventional bare turbine. The net result is that DAWTs encourage a greater overall mass-flow as well as extract more energy per unit of mass-flow passing through the blade-plane than a conventional bare turbine. The major drivers of DAWT performance have been shown to be the ability of the design to maximise diffuser efficiency and produce the most sub-atmospheric exit pressure possible. Parametric investigation of the various DAWT geometric components has shown peak performance to be obtained when: the external flow is directed radially outward by maximising the included angle of the external surface in conjunction with a radially orientated exit flap; by applying boundary-layer control to a trumpet shaped diffuser via a pressurised cavity within the double-skin design of the multi-slotted DAWT; having an exit-area-ratio of the order of 2.22; and by employing an inlet contraction with inlet-area-ratio matched to the mass-flow passing through the DAWT under peak operating conditions. To translate the available augmentation into shaft power a modified blade element method has been developed using an empirically-derived axial velocity equation. The resulting blade designs whose efficiencies reached 77%, twice those of Grumman, highlight the accuracy of the modified blade element method in calculating the flow conditions at the blade-plane of the multi-slotted DAWT. It was also noted that the rotor efficiencies remain below 'best practice' and therefore offer the potential for further increases in shaft augmentation. However, in order to achieve such gains, a number of limitations present in the current method must be addressed. In assessing the likely commercial suitability of the multi-slotted DAWT a number of real-world influences have been examined. Shown to have little if any effect on DAWT performance were Reynolds number, ground proximity and wind shear. Turbulence in the onset flow on the other hand had the beneficial effect of reducing separation within the diffuser. Finally, DAWT performance was assessed under yaw misalignment where it was shown that the multi-slotted DAWT performed favourably in comparison to that associated with a conventional bare turbine. The major drawback identified in the DAWT concept by this investigation was its drag loading and the fact that drag and augmentation were interdependent. The result is that the cost of a conventional DAWT is dictated by the necessity to withstand an extreme wind event despite the fact that augmentation is only required up to the rated wind speed. The overall conclusion drawn was that in order to optimise a DAWT design economically, and therefore make the DAWT concept a commercial reality, a creative solution that minimises drag under an extreme wind event would be required.