The aeroelastic control of wind turbine blades employing active flow controllers is part of an ongoing research effort aiming to alleviate blade loads. Over the past years, the growing body of literature has confirmed the preliminary potential of active flow controllers and, in particular, of control surfaces in relieving wind turbine fatigue and extreme loads. The aim of present research is to investigate the feasibility, design and capability of a multi-component aero-structural load control system utilising light control surfaces such as trailing edge flaps and microtabs. This is achieved through the design of load alleviation control systems, and a detailed understanding of the aeroelastic dynamic of wind turbine blades equipped with control surfaces. As part of this research, a Wind Turbine Aeroelastic Control (WTAC) simulator has been developed. WTAC is the combination of an unsteady aerodynamic module, a structural finite element analysis module, and a control module incorporating the aerodynamic models of control surfaces. The aeroelastic study of the NREL 5MW wind turbine whose blades are equipped with trailing edge flaps and microtabs is carried out using WTAC.

While large-scale wind farms and solar power stations have been used widely as supplement to the nuclear, fossil fuels, hydro and geothermal power generation, at smaller scales these resources are not reliable to be used independently and may result in load rejection or an over size design which is not cost effective. A possible solution to solve this issue is using them as part of a hybrid power system. Complexity in design and analysis of hybrid renewable energy systems (HRES) has attracted the attention of many researchers to find better solutions by using various optimisation methods. Majority of the reported researches on optimal sizing of HRES in the literature are either only considering one objective to the optimisation problem or if more than one objective is considered the effect of uncertainties are ignored. This dissertation work investigates deterministic and stochastic approach in design of HRES. In deterministic approach it shows how adding a battery bank to a grid connected HRES might result in more cost effective design depending on different grid electricity prices. This work also investigates the reliability of HRES designed by conventional deterministic design approach and shows the weakness of common reliability analysis. To perform the stochastic approach the renewable resources variation are modelled using time series analysis and statistical analysis of their available historical meteorological data and the results are compared in this work. Chance constrained programming (CCP) approach is used to design a standalone HRES and it is shown that the common CCP approach which solves the problem based on the assumption on the joint distribution of the uncertain variables limits the design space of problem. This work then proposes a new method to solve CCP to improve the size of design space. This dissertation comprises multi-objective optimisation method based on Non-dominated Sorting Genetic Algorithm (NSGA-II) with an innovative method to use CCP as a tool in estimating the expected value of the objective function instead of Monte-Carlo simulation to decrease the computational time.

Eco-urban electric cars (EC) are superior to conventional cars in terms of the operation cost and carbon footprint. However, the performance of EC in terms of their maximum speed and power, initial and maintenance cost and reliability in the available power is lower than conventional cars. The reliability in available energy can be viewed as the main concerns when comparing EC to conventional cars. Reliability in available energy is highly dependent upon the efficiency of the power system as well as the type and size of batteries. Type and size of batteries have a significant effect on the maintenance cost as well as the initial cost. This thesis is focused on two aspects of the research in electric cars, namely, (i) selection and size optimisation of components, and (ii) improving the reliability of the available energy. Traditionally, a robust design approach is adopted in design of the power system of cars. This is mainly aimed at providing the user with the luxury of using the car wherever there is a suitable road and whenever they want to use the car. This flexibility, however, comes with the price of heavier and more expensive power systems. By incorporating data on the dominant usage of an EC and adopting a deterministic design and optimisation method more cost-effective power systems, more compatible with the usage can be obtained. In this study, a power system simulation tool is developed. Using the simulation tool, the performance of the power system components can be analysed for different usage scenarios. Case studies are conducted. Each case is based on a dominant usage defined for a two-person EC driven in Kayseri city in Turkey. For each case, the best power system configuration is obtained. Another original contribution of this thesis is in the context of the reliability of the available energy, by providing a decision support system - a route planning advisor - that helps the user to select the most suitable route in terms of a variety of criteria both conventional, such as travelling time and travelling distance, as well as EC-related such as, available power, vicinity to a charging station. The optimiser of the developed multi criteria route planning advisor (MCRPA) tool is based on a robust hybrid Dijkstra - A* - NSGA-II algorithm. MCRPA incorporates information on EC characteristics (such as power system, aerodynamic shape, weight), city characteristics (current traffic flows, road types, speed limits, altitude, whether conditions), and city charging stations characteristics (capacity, charging level, crowding density). Carrying out case studies, the efficiency and performance of the MCRPA is evaluated.

A novel heat pipe (HP) manufacturing method has been developed based on an additive layer manufacturing technique called “selective laser melting” or SLM. This innovation is expected to benefit current applications of aluminium/ammonia heat pipes in space and terrestrial projects as well as many new HP applications. The project was jointly sponsored by the Northumbria University and Thermacore, a world leading heat pipe manufacturing company in the UK, and formed the feasibility stage of a much larger program in Thermacore aiming to develop the next generation of HPs for space applications. In this project, sinter-style aluminium SLM HPs have been produced and tested to prove their functionality and to provide an overall image of the new production process with regard to the major involved parameters. During the project several properties of the new heat pipes e.g. wick porosity, permeability and pore size; wall density, hardness, vibration resistance and optimum SLM build parameters have also been determined by the existing or especially developed rigs in Thermacore or Northumbria University laboratories including scanning electronic microscope (SEM), vibration table, permeability measurement rig, etc. Converting the SLM products into functional heat pipes involves many other steps which have also been completed and explained. At the end of the project two successful functional samples were obtained and clear and precise answers were found to the project questions. SLM process was proved to be capable of producing functional heat pipes. Functional sinter-style heat pipes are proved to be producible by SLM. A numerical design tool is now available to evaluate SLM produced heat pipes and major challenges of this new HP production process including the density of the solid structures and possible contamination of the materials have been identified. Also a reasonably good overall image of this new HP production process and the new HPs has been provided in this project through the conducted measurements and experiments. The contribution of this project to knowledge is supported by two papers published in prestigious heat pipe journals and one paper presented in the 16th international heat pipe conference.

In this thesis a number of open problems in the theory of ordinary differential equations (ODEs) and dynamical systems are considered. The intention being to address current problems in the theory of systems control and synchronisation as well as enhance the understanding of the dynamics of those systems treated herein. More specifically, we address three central problems; the determination of exact analytical solutions of (non)linear (in)homogeneous ODEs of order 1 and 2, the determination of upper/lower bounds on solutions of nonlinear ODEs and finally, the synchronisation of dynamical systems for the purposes of secure communication. With regard to the first of these problems we identify a new solvable class of Riccati equations and show that the solution may be written in closed-form. Following this we show how the Riccati equation solution leads us quite naturally to the identification of a new solvable class of 2nd order linear ODEs, as well as a yet more general class of Riccati equations. In addition, we demonstrate a new alternative method to Lagrange's variation of parameters for the solution of 2nd order linear inhomogeneous ODEs. The advantage of our approach being that a choice of solution methods is offered thereby allowing the solver to pick the simplest option. Furthermore, we solve, by means of variable transforms and identification of the first integral, an example of the Duffing-van der Pol oscillator and an associated ODE that connects the equations of Lienard and Riccati. These fundamental results are subsequently applied to the problem of solving the ODE describing a lengthening pendulum and the matter of bounded controller design for linear time-varying systems. In addressing the second of the above problems we generalise an existing GrOnwall-like integral inequality to yield several new such inequalities. Using one of the new inequalities we show that a certain class of nonlinear ODEs will always have bounded solutions and subsequently demonstrate how one can numerically evaluate the upper limits on the square of the solution of any given ODE in this class. Finally, we apply our results to an academic example and verify our conclusions with numerical simulation. The third and final open problem we consider herein is concerned with the synchronisation of chaotic dynamical systems with the express intention of exploiting that synchronisation for the purposes of secure transmission of information. The particular issue that we concern ourselves with is the matter of limiting the amount of distortion present in the message arriving at the receiver. Since the distortion encountered is primarily a due to the presence of noise and the message itself we meet our ends by employing an observer-based synchronisation technique incorporating a proportional-integral observer. We show how the PI observer used gives us the freedom to reduce message distortion without compromising on synchronisation quality and rate. We verify our results by applying the method to synchronise two parameter-matched Duffing oscillators operating in a chaotic regime. Simulations clearly show the enhanced performance of the proposed method over the more traditional proportional observer-based approach under the same conditions. The structure of thesis is as follows: first of all we describe the motivation behind object of study before going on to give a general introduction to the theory of ODEs and dynamical systems. This lead-in also includes a brief history of the theory of ODEs and dynamical systems, a general overview of the subject (as wholly as is possible without getting into the mathematical detail that is left to the appendices) and concludes with a statement of the scope of the thesis as well as the contributions to knowledge contained herein. We then go on to state and prove our main results and contributions to the solution of those problems detailed above starting with the solution of ODEs.

In response to the high demand of the operation reliability by implementing real-time monitoring and system health management, the three-year PhD project focuses on developing robust fault diagnosis and fault tolerant control strategies for complex systems with high-nonlinearities, stochastic Brownian perturbations, and partially decoupled unknown inputs, which are then applied to wind turbine energy systems. Integration of serval advanced approaches, including the augmented system method, unknown input observer design, Takagi-Sugeno fuzzy logic, linear matrix inequality optimization, and signal compensation techniques enable us to achieve robust estimations of both the system states and the faults concerned simultaneously, while removing/reducing the adverse influences from faults to the system dynamics. Prior to the existing work, the considered unknown inputs can be partially decoupled rather than completely decoupled, which can meet a wider practical requirement. Moreover, the systems under investigation can be linear, Lipschitz nonlinear, quadratic inner-bounded nonlinear, high-nonlinear characterized by a Takagi-Sugeno fuzzy model, and stochastic with Brownian perturbations, which can cover a wide range of real industrial plants. Specifically, the augmented system method is used to construct an augmented plant with the concerned faults and system states being the augmented states. Unknown input observer technique is thus utilized to estimate the augmented states and decouple unknown inputs that can be decoupled. Linear matrix inequality approach is further addressed to ensure the stability of the estimation error dynamics and attenuate the influences from the unknown inputs that cannot be decoupled. As a result, the robust estimates of the faults concerned and system states can be obtained simultaneously. Based on the fault estimates, a signal compensation scheme is developed to remove/offset the effects of the faults to the system dynamics and outputs, leading to a stable dynamic satisfying the expected performance. A case study on a 4.8 MW wind turbine benchmark system is proposed to illustrate and demonstrate the proposed integrated fault tolerant control techniques. Takagi-Sugeno modelling of a wind turbine system is presented as a by-product. To summarize, the proposed integrated fault estimation and fault tolerant control strategy can handle a system with highly nonlinear dynamics in a strong disturbance/noise environment (e.g., partially-decoupled process disturbances and stochastic parameter perturbations), which is validated by a real-time wind turbine system. As a result, the presented methods/algorithms have enriched fault diagnosis and tolerant control theory with high-novelty and great potentials for practical applications.

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Discontinuous and particulate metal matrix composites have emerged as a set of materials which has found increasing niche areas of use. They are now widely used in both diesel and petrol internal combustion engines, as well as in sports bicycles and other areas where their combination of unique properties can be exploited to advantage. The inclusion of fibres into a base matrix produces a complex material both in its make up and mechanical properties and it would be an advantage to be able to predict a candidate metal matrix composite material's mechanical and thermal properties prior to that material's development. One such approach, the so called Theory of Cells, is a micromechanical approach which uses the analysis of repeating cells within the composite to make prediction of the composite's mechanical properties. In the present study, this approach has been employed to predict the fatigue life of a series of different metal matrix composites at ambient temperature. These composites include some materials with SiC fibres and some with Al203 fibres. Using data obtained from the monolithic matrix material and the individual fibres theoretical S/N and Strain/N curves were produced. This was possible by assuming that the matrix material in the composite fails at the same fatigue stress level as does the monolithic matrix material or, if fibres fail, this will be at the failure level of the individual fibres. These curves were then compared to experimental data for all metal matrix composites and good agreement was obtained for all but the low cycle fatigue regime. A finite element programme was employed to predict fatigue life in the low cycle fatigue regime and the results were compared to the predictions made by the Theory of Cells. It was found that the finite element was no better at predicting the fatigue life of the composite than the Theory of Cells. Both systems however predicted an area of high stress in front of the fibre in the direction of loading. Fatigue tests were carried out on one particular material at both 200°C and 300°C and the fatigue life was compared to that predicted by the Theory of Cells. It was found that the predictions became increasingly inaccurate with increasing temperature.

Inlet port flow characteristics are critical in determining the overall performance of diesel combustion systems. The relationship between inlet port geometry and performance has long been a subject of interest to many researchers, although as yet a comprehensive understanding remains elusive. The ongoing need to provide advanced powertrain design solutions in order to meet increasingly stringent emissions legislation, whilst meeting customer expectations and minimising engineering costs, has driven the development of new approaches to engine design. In particular, the fundamental advantages of multivalve technology, coupled with rapidly improving fuel delivery systems has placed new requirements on inlet port performance characteristics. Statistical methods and knowledge-based design are emerging as potentially powerful tools in this field of research, supported by rapid developments in computing power.

A novel technique is presented in which two colour, two dimensional, time-resolved Laser induced incandescence (2C-2D-TiRe-LII) is used to produce planar spatially resolved, quantified, soot particle sizing. The technique is applied to a well characterized laboratory flame (Santoro burner) for validation. Accordance with other research efforts of spatial distribution of soot particle size was demonstrated.