Due to environmental concerns, offshore wind plant will play an important role in next decades for meeting the requirement of carbon emission and renewable energy target. The variable speed wind turbine will not have a load-frequency response similar with traditional synchronous generator which may cause the inertia less problems in the system. The UK National Grid has developed scenarios where high wind power penetration levels are considered which are likely to change the patterns of UK transmission network operation and dynamic performance. Therefore, it is necessary to develop an analytical capability which can assess the system dynamic performance ahead of the anticipated changes. Although some work has been reported in this area, the studies are either based on very simple network representations or involve very complex proprietary network modelling not publically available and with results which are often difficult to interpret. This thesis aims to develop appropriate ways of deriving a representative dynamic system model using UK transmission system as a benchmark. The methodology "Individual channel analysis and design (ICAD)" is utilized to realise the trade-off between plant dynamical requirements (feedback design) and the limitations (coupling effects) on achieving such requirements in multivariable system. A representative 21 bus dynamic model of the entire UK transmission system based on Ten Year Statement has been developed and implemented in Power System Simulator (PSS/E). A few recent system-wide events, captured by the existing Phasor Measurement Units (PMU), have been used to validate the frequency response of the model. Moreover, the General Electric (GE) type DFIG models are added for the purpose of analysing the future system performance with the increasing penetration levels of wind energy. The case study reveals that improvements are to be had by transmission line reinforcements under appropriate wind energy distribution scenarios with system transient stability largely improved. The impact of key influencing factors such as the size of the largest generating unit for n-1 contingency, amount of primary system response, frequency dependency of load, and others are presented. The study concludes that none of the individual factors can provide a complete solution and that careful cost benefit analysis is needed to determine the proper mix of services and reinforcements needed in the future.

The control of microbial contamination in the food industry is critical, as contamination of food produce, surfaces and equipment can lead to acquisition of foodborne infections. Microbial contamination can also result in food spoilage, which can cause both product and financial loss. Consequently novel decontamination technologies are being sought to help reduce contamination. Initial investigations examined the efficacy of 405 nm light for inactivation of a range of common foodborne microorganisms, both in suspension and on agar surfaces. All exposed populations were significantly reduced following 405 nm light exposure. The hypothesised inactivation mechanism involves photoexcitation of endogenous porphyrin molecules within the microorganisms, resulting in production of reactive oxygen species, oxidative cell damage and microbial inactivation. This theory was investigated by exposing fungi to 405 nm light under both aerobic and anaerobic conditions. Results displayed significant reduction in inactivation rates under oxygen depleted conditions, highlighting the critical role of oxygen during 405 nm light inactivation. This study also demonstrated inactivation of bacterial contamination and biofilms on a range of surfaces, demonstrating potential environmental decontamination applications. Further work highlighted the enhanced bacterial inactivation efficacy of 405 nm light when bacteria were exposed under sub-lethal environmental conditions, typical of those present in the food processing industry. Further studies also demonstrated the synergistic effect of TiO2 with 405 nm light, thereby enabling significantly enhanced bacterial inactivation rates. Studies also investigated potential applications for food decontamination and preservation, with preliminary results highlighting successful prevention of spoilage on a range of food products and significant decontamination of E. coli on fresh fruit. This study has confirmed the microbicidal efficacy of 405 nm light, whilst demonstrating a range of potential applications for use within the food industry for improved environmental decontamination. In conclusion 405 nm light has potential to be used safely and effectively as an additional decontamination technology in the food industry.

The work presented in this thesis focusses on new techniques for capture and analysis of hyperspectral data. Due to the three-dimensional nature of hyperspectral data, image acquisition often requires some form of movement of either the object or the detector. This thesis presents a novel technique which utilises a rotational line-scan rather than a linear line-scan. Furthermore, a method for automatically calibrating this system using a calibration object is described. Compared with traditional linear scanning systems, the performance is shown to be high enough that a rotational scanning system is a viable alternative. Classification is an important tool in hyperspectral image analysis. In this thesis, five different classification techniques are explained before they are tested on a classification problem; the classification of five different kinds of Chinese tea leaves. The process from capture to pre-processing to classification and post-processing is described. The effects of altering the parameters of the classifers and the pre and post-processing steps are also evaluated. This thesis documents the analysis of baked sponges using hyperspectral imaging. By comparing hyperspectral images of sponges of varying ages with the results of an expert tasting panel, a strong correlation is shown between the hyperspectral data and human determined taste, texture and appearance scores. This data is then used to show the distribution of moisture content throughout a sponge image. While hyperspectral imaging provides significantly more data than a conventional imaging system, the benefits offered by this extra data are not always clear. A quantitative analysis of hyperspectral imaging versus conventional imaging is performed using a rice grain classification problem where spatial, spectral and colour information is compared.

The implementation of the SIP-based Voice over IP (VoIP) and multimedia over MANET is still a challenging issue as many routing factors affect the SIP signaling performance and the voice Quality of Service (QoS). The nodes' mobility in MANET cause dynamic changes on the route calculations, topology, hop numbers, and the connectivity status between the correspondent nodes. The SIP-based VoIP depends on the caller’s registration, call initiation, and call termination processes. Therefore, the SIP signaling performance has an important role for the overall QoS of SIP-based VoIP applications over IPv4 and IPv6 MANET. The SIP end-to-end performance metrics have been defined in RFC 6076 to provide a standardized method of evaluation for the performance of the SIP signaling system over different platforms. However, no benchmarked values for these metrics have been proposed yet. In this thesis, an evaluation studies for the performance of the SIP signaling system over the AODV-based and OLSR-based MANET introduced using various mobility models. The related SIP end-to-end performance metrics were employed for the performance investigations and enhancement efforts for the SIP signaling system. The evaluation study was used to benchmark the related performance metrics for the SIP signaling system in general. In addition, the study evaluated the implementations of the ROHC-based system over IPv6 MANET for SIP-based VoIP. Furthermore, novel Cross-Layer performance enhancement approaches are proposed, implemented, and evaluated to improve the performance of the SIP signaling system over MANET based on simple dynamic modifications for the routing parameters. The SIP performance metrics reflect the SIP signaling state and the required actions for the routing parameters. The implementation of the Cross-Layer approaches succeeded in reducing the total delays in the SIP processes, enhanced the signaling performance, and increased the utilisation level in the system bandwidth and routing processes.

Modern industrial society, increasing energy demands, and environmental issues have increased the need for new and clean renewable energy resources, among which photovoltaic energy has gained considerable interest. For best energy utilization, photovoltaic maximum power tracking and grid-integration aspects should be addressed. Generally, variable-step, incremental conductance maximum power point tracking technique has the merits of good tracking accuracy and fast convergence speed. Yet, the division processes in its algorithm create a computational burden. Also the conventional variable step-size encounters steady-state power oscillation and dynamic problems, especially under sudden irradiance changes. In this thesis, a division-free incremental conductance algorithm is proposed for photovoltaic maximum power tracking. It features a modified variable step-size and a direct converter control scheme. The proposed tracking technique does not only have the merits of superior steady-sta te and transient performance but also offers simple implementation and control. Thus, it can be practically implemented using low-cost microcontrollers, reducing overall system cost. Grid integration of photovoltaic systems using power electronic converters that vary in configurations, control loops and mandatory measured signals are investigated. A singlephase two-stage grid-interfaced photovoltaic system is presented in this thesis. It uses a boost chopper in the first stage for maximum power tracking and an H-bridge voltage source inverter in the second stage for grid interfacing. A novel DC-link voltage sensorless control technique is proposed for this topology. It eliminates the inverter outer DC-link voltage control loop, thus reducing system size, cost and control complexity. Additionally, system dynamics are enhanced during sudden changes. Single-stage based grid-tied photovoltaic power converters receive attention due to their merits of reduced footprint and losses, but at the cost of a limited degree-of-freedom. In this thesis, a single-phase single-stage grid-tied photovoltaic system is proposed. It adopts a single transformerless current source inverter to achieve photovoltaic maximum power tacking, whilst satisfying grid interfacing requirements. A proportional-resonant controller, associated with harmonic compensator units, is proposed for the inverter in order to limit injected grid current harmonics. Thus, a lower-sized inductor can be used in the inverter DC-link which enhances efficiency without sacrificing system performance. Simulation and experimental results validate all the proposed systems.

The control of crystallisation of complex oxides on the nano- and macro-scale is vital for the progression of technology and the fundamental understanding of the processes which govern functional oxide synthesis. The use of biotemplates has been shown to be a highly effective means of controlling both the phase and morphology of complex oxides, with macro- and nano-structures being formed which would otherwise be impossible using standard synthetic techniques. One complex functional material, yttrium barium copper oxide (YBCO), has generated huge amounts of interest for its superconducting properties, in particular its relatively high transition temperature (93 K), however given the complex nature of its crystal structure, it has proved to be very difficult to illicit control over the crystallite growth on the nano- or larger scales. Standard synthetic techniques, whilst very effective in producing a pure phase, are either slow or prohibitively expensive, and, due to the processes involved, offer no control over the final morphology. Herein are presented several new methods for the production of superconducting YBCO, including macro-scale control of polycrystalline samples in the formation of hollow microspheres through the use of the polysaccharide dextran, monolithic foams and highly layered tapes using a graphene oxide template, and nano-scale control to produce nanowires, through which a type of nanowire growth, the microcrucible mechanism, which has been directly observed and characterised for the first time. In addition, two sulphur-containing templates, K-carrageenan and a barnacle cement protein, which were thought to be unsuitable for use with YBCO (and any other phases containing precursors which would form stable sulphates during synthesis) were also investigated and found, after careful optimisation of the synthesis protocol, to be useable under certain experimental constraints. This is significant as it means that sulphur-rich proteins can now be successfully used for the production of YBCO, with the possibility of creating designer morphologies, giving even higher control over crystallisation. Each templating protocol was fully investigated using the standard chemical and physical characterisation techniques such as powder X-ray diffraction and transmission electron microscopy, in order to examine the phases and morphologies produced, and the superconducting properties investigated using a superconducting quantum interference device magnetometer. Where appropriate a number of other techniques such as in situ measurements using heating stages or X-ray micro computer-aided tomography were employed to give a deeper understanding of each templated system. The templating systems detailed here for YBCO should be applicable for other complex oxides, with the insights gained into the mechanisms which govern the phases and morphologies formed allowing optimised systems to be more quickly developed. This may lead to further advances in the production of complex functional oxide materials

Electric propulsion provides many benefits when compared to fully-mechanical power transfer. These benefits include increased configurability, efficiency, ease of control and an ability to offer redundancy. The improved fuel-consumption offered by hybrid electric-mechanical propulsion systems is particularly important to the transport sector. Recent governmental and climate-change targets, which have been driven by the depletion of fossil-fuel reserves, place a growing focus on these propulsion and actuation technologies. The demand to electrify existing commercial products burdens manufacturers to develop and mature electrical systems such that they can be produced in high volumes at low-cost. This pressure places a strong emphasis on the adopted design procedure's suitability for a given application and system requirements. A series-hybrid transmission system for a skid-steered vehicle forms the basis of presented work. The thesis design focus is a high-speed, fault-tolerant electrical machine and is purposed to actuate a "steering input" on this bespoke transmission. The electrical machine design requirements are unusual. The physical envelope is unconstrained and the transmission will be designed to accommodate the prototype; however, a compact machine with minimised mass is desirable. A design methodology for modular-wound electrical machines is developed and presented. The method draws upon published work in electro-magnetic and thermal optimisation; however it is specifically tailored to handle a design problem with an unspecified physical envelope. It is shown that a template electro-magnetic design may be generated to produce an optimal initial geometry; this template is subject to a thermal scaling study which ensures the output requirements are satisfied. Sub-assembly testing provides a useful approach for obtaining difficult to model thermal parameters and calibrating 'stray' AC loss effects. The presented methodology requires fewer design iterations when compared to common procedures; furthermore, it reduces the overall design and prototyping costs without incurring a disproportionate increase in computation-time. The research culminates in a prototype 12000 rpm, 40 kW, 12-slot, 10-pole, interior permanent magnet electrical machine. Electrical fault-tolerance is demonstrated utilising a segmented, 3-phase "machine-modular" stator design, comprising of single-layer concentrated windings. The machine stator is constructed with inexpensive solid conductors. With careful consideration of winding conductor placement, reduced AC losses are exhibited which yields a prototype with a competitive power-density. The dominating factor which governs a machine's achievable specific-output is shown to be the stator's thermal characteristics. These characteristics are not only a function of the materials and construction techniques used, but are equally impacted by stator split-ratio and the choice of physical envelope. The presented design method allows these envelope dimensions to be identified and generates an initial design which is close to the global optimum.

This thesis contains experimental and theoretical work on two highly important aspects of electric current flow in solids. In Part 1 electromigration in metals is discussed and observations of the nucleation and growth of voids in aluminium microcircuits reported. The importance of stress driven diffusional backflow is highlighted and shown to play an analogous role to work hardening during plastic flow. In the second half of Part 1, a new expression for the force exerted on the lattice ions by the electrons of a current carrying metal is derived. The analysis is shown to be applicable to the similar problem of electrical resistivity and the predicted values for both electromigration mass transport and resistivity compare favourably with other expressions in the literature, and with experiment. Part 2 contains results of magnetisation measurements on the high temperature superconductor YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7</SUB>. Many of the essential parameters have been measured including perhaps the first data for the pinning penetration depth and the interaction distance. The results are shown to imply that YBa<SUB>2</SUB>Cu<SUB>3</SUB>O<SUB>7</SUB> contains weak links approximately 1μm apart.

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