Nanotechnology is currently emerging as the next industrial revolution. It enables the production of goods (i.e. nanoproducts, NPs) with enhanced functionalities, which have nonetheless caused mounting concerns about the potential implications they can have on the environment, economy and society. This thesis employs Multiple Criteria Decision Aiding (MCDA), one form of decision support, to aid the sustainable development of nanotechnology. The first original contribution of this doctoral research is the development of a framework of sustainability assessment criteria for NPs, through a three-phase procedure based on the MCDA process, including a literature review, a pilot and a main survey. It lead to a comprehensive framework of 68 criteria, ranked according to their relative importance, allocated to six main domain areas: (i) economic performance; (ii) environmental impacts; (iii) environmental risk assessment; (iv) human health risk assessment; (v) social implications; and (vi) technical performance. All the criteria are reliable and can be used in real case studies to increase the knowledge about the sustainability of NPs. The second original contribution presented in this thesis is a robust model (DRSA-based model) based on green chemistry principles implementation for the classification of synthesis processes of nanomaterials in preference-ordered classes. This tool was developed through knowledge elicitation techniques based on coconstructive MCDA with the collaboration of two experts (the decision makers) in synthesis of nanomaterials. The robustness of the ensuing model was assessed (and confirmed) by means of another model developed ad hoc (ELECTRE-based model), structured on an MCDA method implementing a stochastic multiple criteria classification strategy. The results confirm that MCDA is an effective decision support approach to foster sustainable development of nanotechnology, providing that the analysts who apply it take these considerations into account. They must ensure that (1) multidisciplinary teams are created to perform comprehensive and credible sustainability evaluations; (2) problem structuring and model construction are as important as (if not more important) than the results (i.e. decision recommendations) themselves; (3) identification of the appropriate MCDA method depends on the problem at hand and not vice-versa; and (4) the credibility of the decision recommendations is subject to the preferences of the decision-makers. If these considerations are accounted for, the possibility of advancing nanotechnology on a sustainable path is very concrete and realistic.

Surface water flooding due to the inadequacy of local drainage is a significant UK concern (DEFRA, 2005; POST, 2007). Urban flood modelling and mapping are typified by characteristic terrain difficulties (Charteris et al., 2001). These difficulties include topographic complexity (road crests and gutters; raised house pads); infrastructure (including houses, fences, garden beds, etc); and, complex underground pipe networks (Charteris et al., 2001; Mark et al., 2004a & b; Hunter et al., 2008; Neelz & Pender, 2007; Syme 2008). Designed to mitigate surface waters, drainage systems play a central role and include key features such as sewer pipes, kerbside gutter channels, gully pots and drains. These systems are often highly complex and spatially varied, simultaneously representing alternate flood pathways, hydraulic sinks and, potentially, additional flood sources (DEFRA, 2005). Accurate flood mapping (DEFRA, 2012) requires data rich modelling and, potentially, dynamic linking of models to form an integrated representation of urban surface and subsurface systems (DEFRA, 2005). Predicted data serves to estimate potential physical impacts, assessing likely damage to buildings and urban infrastructure (Kelman & Spence, 2004); or enhancing mapping further with peak velocities to provide detailed assessment of hazards to people (DEFRA, 2006; 2012). However such Integrated Urban Drainage (IUD; Gill, 2008) approaches are resource expensive (time and data requirements). Research into approaches offering more efficient representations is considered essential and timely. Therefore, the possible inclusion of proxy-model approaches offers an alternate tool for rapid hazard appraisal. Using a UK case-study approach, this Thesis addresses IUD modelling deficiencies through two specific aims: (i) examining IUD model development and impact on hazard prediction and, (ii) investigation of more resource-efficient proxy model approaches to the fully Integrated Urban Drainage model. Using TUFLOW hydrodynamic software (WBM, 2008), an IUD model of a dense UK urban area (2 sq km) is developed and examined. Firstly through small-scale IUD modelling showing improved IUD model performance with kerbside drainage and flow capture systems, particularly when based on depth-inflow criteria and, secondly, through enhanced infrastructure representation. Outputs are examined for both fluvial and pluvial source floods of the statutory 1% AEP event (HMSO, 2009). Data indicates significant IUD impact in terms of extent reductions of 56% (fluvial) and 30% (pluvial), and consequently mean peak depth reductions of 33% (fluvial) and 20% (pluvial) flood events. Velocity impacts are shown to be near negligible, recording less than 1% variation for each flood event. Examination of IUD proxy-model approaches identified inappropriate use for fluvial flood event modelling. Pluvial event surface water modelling identified approaches based on a uniformly applied adjustment of the 5% AEP Design Flood Frequency event (BS, 2008) showed most (95%) agreement to the full pluvial IUD model. This Thesis’ outcomes have supported current flood risk modelling and appraisal practice by Capita Symonds and WBM Pty Ltd (TUFLOW authors). Notable recent projects include Hereford, England (2010), Gold Coast City, Australia (2012) and Christchurch, New Zealand (2014).

Charge trapping at the channel interface is a fundamental issue that adversely affects the reliability of metal-oxide semiconductor field effect transistor (MOSFET) devices. This effect represents a new source of statistical variability as these devices enter the nano-scale era. Recently, charge trapping has been identified as the dominant phenomenon leading to both random telegraph noise (RTN) and bias temperature instabilities (BTI). Thus, understanding the interplay between reliability and statistical variability in scaled transistors is essential to the implementation of a ‘reliability-aware’ complementary metal oxide semiconductor (CMOS) circuit design. In order to investigate statistical reliability issues, a methodology based on a simulation flow has been developed in this thesis that allows a comprehensive and multi-scale study of charge-trapping phenomena and their impact on transistor and circuit performance. The proposed methodology is accomplished by using the Gold Standard Simulations (GSS) technology computer-aided design (TCAD)-based design tool chain co-optimization (DTCO) tool chain. The 70 nm bulk IMEC MOSFET and the 22 nm Intel fin-shape field effect transistor (FinFET) have been selected as targeted devices. The simulation flow starts by calibrating the device TCAD simulation decks against experimental measurements. This initial phase allows the identification of the physical structure and the doping distributions in the vertical and lateral directions based on the modulation in the inversion layer’s depth as well as the modulation of short channel effects. The calibration is further refined by taking into account statistical variability to match the statistical distributions of the transistors’ figures of merit obtained by measurements. The TCAD simulation investigation of RTN and BTI phenomena is then carried out in the presence of several sources of statistical variability. The study extends further to circuit simulation level by extracting compact models from the statistical TCAD simulation results. These compact models are collected in libraries, which are then utilised to investigate the impact of the BTI phenomenon, and its interaction with statistical variability, in a six transistor-static random access memory (6T-SRAM) cell. At the circuit level figures of merit, such as the static noise margin (SNM), and their statistical distributions are evaluated. The focus of this thesis is to highlight the importance of accounting for the interaction between statistical variability and statistical reliability in the simulation of advanced CMOS devices and circuits, in order to maintain predictivity and obtain a quantitative agreement with a measured data. The main findings of this thesis can be summarised by the following points: Based on the analysis of the results, the dispersions of VT and ΔVT indicate that a change in device technology must be considered, from the planar MOSFET platform to a new device architecture such as FinFET or SOI. This result is due to the interplay between a single trap charge and statistical variability, which has a significant impact on device operation and intrinsic parameters as transistor dimensions shrink further. The ageing process of transistors can be captured by using the trapped charge density at the interface and observing the VT shift. Moreover, using statistical analysis one can highlight the extreme transistors and their probable effect on the circuit or system operation. The influence of the passgate (PG) transistor in a 6T-SRAM cell gives a different trend of the mean static noise margin.

This research thesis presents an analysis of the torsional loads on V-band clamps. In some applications, the relative rotational movement of the flanges connected by V-band clamps can result in catastrophic system failure. The ability to understand the factors impacting on torsional load capacity is therefore essential. In this research project, a theoretical model of a V-band joint subjected to torsional loads was developed. This model is used to identify those parameters that will impact on the joint’s reliability. An experimental investigation was conducted to validate a theoretical model using a newly developed test rig. The development and features of this test rig are presented in this report. This experimental investigation also allowed the impact of those parameters that are difficult to control, to be determined. A total of three V-bands were used with different diameters but nominally identical cross sections were studied. In the research results, the initial slip point between flanges and the V-band clamp was identified by experimentation within this research project. Different sizes of Vbands were used under boundary conditions and loads. From the simulation results it was determned that the friction effect on the V-band depends on the size of the V-band. For the largest size of V-band, there was moderate correlation of the experimental and theoretical results. For the smallest size, the results suggest that with band tightening, flange contact is localised, rather than being throughout the band’s entire circumference. The research demonstrated the significant relevance of the band and flanges’ contact points and the coefficient of friction, especially that between the flanges, on the V-band clamp’s theoretical torsional load capacity.

The control of a moving structure in an unbounded flow has numerous applications in engineering, such as the aileron on an airplane. Here an approach is proposed where a CFD method is coupled with a controller to provide a qualitative flow model, and a tool for the development and the validation of the control scheme. A rotating rigid flat plate in transverse flow is considered. For the CFD, a discrete vortex method is used due to its relevance for separated flows, which implies approximating the flat plate by a thin ellipse. The simulation for a fixed plate has been completed with a plate approximated by a 20:1 ellipse and placed in an inviscid flow. A comparison with an image method is also undertaken. The results show encouraging features for modelling the vortex street, but also problems in the transient behaviour of the flow. The control method is based on fuzzy logic, and has shown a remarkable ability to adapt to the nonlinear nature of the force generated by the flow/structure system. Comparison is made with more classical schemes such as a controller based on optimal control theory using an intermediary flow/structure model, similar to a gain scheduling model, instead of the full simulation.

This thesis describes the investigation of the electrochemistry principles, technology, construction and composition of the electrode materials, electrolyte and additives used in redox flow batteries. The aim was to study a flow battery system with an appreciable working performance. The study explores and compares mainly three different redox flow battery technologies; all-vanadium, soluble lead-acid and a novel copper-lead dioxide flow batteries. The first system is based in sulfuric acid electrolyte environment whilst the other two are in methanesulfonic acid. Various cell parameters such as cell voltage, individual electrode potentials, flow rate and efficiencies (in particular voltage, charge and energy) have been utilized to compare. Further research in other redox couples and comparative study towards the design, construction and electrochemistry, along with the performance of these three batteries in relation to other electrochemical energy storage technologies available was also discussed. These technological studies are of particular interest for applications in the renewable energy storage (offshore and onshore) and sustainable energy research (grid integration and micro generation).

The extreme sport of Skeleton faces driver-training constraints. GB Skeleton athletes are limited to 120 minutes of track time per year. This PhD focuses on the learning effects from virtual environment (VE) training. It was hypothesised that learning and skill-acquisition within the sport of Skeleton could be accelerated through the use of physical simulation and VE training. This has been investigated by linking various perceptual learning paradigms to the design of VE training. A review of previous simulator development and learning intervention research found an apparent lack of task specificity in VE design. This led to initial perceptual learning theories that focused on task specific stimuli cueing. Two on-ice track-testing sessions were conducted. They primarily provided the acquisition of on-track sled dynamic measurements and athlete subjective data, which helped formulate hypotheses around which cueing stimuli was important within a VE training scenario. Test results showed: dominance of g-force proprioceptor stimuli, and an inhibited visual stimuli domain. Following these tests an experiment was conducted using a prototype simulator to investigate if proprioceptor stimuli had an effect on athlete sliding performance and in-simulator learning rates. The results from the 5-subject experiment concluded that mechanically-applied proprioceptor stimuli during virtual training showed improvement of in-simulator learning rates and task performance. The findings promoted the development of new VE feature theories. These theories promoted efficient VE design to maximise learning by customising task specific cueing systems. A novel virtual simulator was developed to investigate these theories. The simulator included; a real-time physics engine for athlete interaction, virtual graphics with 180deg field-of-view vision, high (5-80Hz) and low (up to 5Hz) frequency proprioceptor stimulation using vibration and forcefeedback controlled body loading, vestibular system stimulation from whole body roll motion, and virtual audio generation. A motion cueing experiment was conducted, aimed at identifying if the addition of whole-body roll motion led to an increased learning rate. Subject learning rate and performance was evaluated from steer timing error measurements. Subjective feedback was provided which supported the measured results. The experiment showed that motion cueing accelerated the rate of in-simulator learning for task specific events where vestibular stimulation led to faster perceptual information processing. Three verification methods for simulator evaluation were used to investigate the effectiveness of skill transfer from simulated to real-world environment. Subjective and objective measures assessed the effects each VE subsystem had on subjects’ ability to perform the task. The system’s applicability and validity as a perceptual priming tool was demonstrated and shown; from pre and post simulator intervention of athlete improvement comparisons, real-vs-simulated sled dynamics, and subject matter expert opinion. Compelling evidence was presented to suggest that positive transfer of training occurred. It is concluded that a low-cost VE for Olympic Skeleton training did accelerate the rate of learning and increase athlete performance.

The focus of this thesis is the measurement of specific aeroacoustic properties in ducts at frequencies below the cut-on frequency of the first higher order mode. A body of measurement results are presented which highlight the effect of flow on some of the aeroacoustic characteristics in ducts as well as describe the aeroacoustic sources of an in-duct orifice and a simple expansion chamber. The results have been compared with published theory where appropriate. Important developments from measurements of the acoustic characteristics of a simple duct with flow include a new experimental method to determine the viscothermal attenuation coefficient. In addition, pressure reflection coefficient measurements of an unflanged duct with flow with two different edge conditions are used in conjunction with a numerical model developed by Gabard [1] to determine the extent of vorticity shed from the duct termination. A novel method is presented for the measurement of aeroacoustic source strengths in ducts with flow. The source is defined in terms of acoustic power and is determined by measuring the acoustic power flux both upstream and downstream of the source region in a duct. The method adopts a plane wave approximation and was assessed experimentally by creating a source in a duct at a number of known frequencies and modifying its magnitude by a known amount. The source measurement technique is applied to an in-duct orifice. The results are used to determine the spectral characteristic and velocity dependence of the source. The results indicate that the duct-to-orifice area ratio has a important effect on the spectral characteristics and velocity dependence of the source. New measurements of the aeroacoustic source strength of a simple flow excited expansion chamber are presented. The results indicate that lock-on flow tones occur when hydrodynamic modes which form in the chamber match the tailpipe resonant frequencies. The results are compared with predictions of a model based on describing function theory

This thesis is concerned with the surface discharge behaviour at the oil-pressboard interface. For large transformers this is classified as a serious failure mode because it can lead to catastrophic failure under normal AC voltage operating conditions. To increase understanding on this failure mode, a surface discharge experiment at the oil-pressboard interface has been conducted on different moisture levels in pressboard by applying a long period of AC voltage stress. The processes in the surface discharge at the oil-pressboard interface until the appearance of a first full discharge have been recognised and correlated with the measured data. The results show that the different moisture levels within the pressboard play an important role on the partial discharge (PD) activity of certain processes. The decreasing trend in the PD data during the surface discharges cannot be treated as a reliable condition monitoring measure of health because it is the key indicator of white marks propagation toward the earth point. The characteristics of full discharge events have been analysed to develop knowledge for condition monitoring of surface discharge at the oil-pressboard interface. Full discharges are corona-like events in which their random occurrences are dominated by accumulated charges on the pressboard surface along the white marks rather than the polarity of applied AC voltage. A 2-D axial symmetry surface discharge model has also been developed using COMSOL Multiphysics, a finite element analysis (FEA) software package. The model considers the pressboard region near the interface (a transition region) as porous, whilst in the bulk region of pressboard as a perfect insulator. The model is developed using continuity equations and coupled with the Poisson’s equation to study the problem in terms of charge transport mechanisms and electric field distributions. The thermal conduction equation is included to study the thermal effects of surface discharge activity at the oil-pressboard interface. The behaviour of surface discharge is studied by validating the simulated surface discharge current pulse with the measured current. The simulation results show that a field dependent molecular ionisation mechanism plays an important role in the streamer propagation during the period of the rising front of the current pulse, whilst during the period of decaying tail of the current pulse, the contribution of an electron attachment process is dominant. The modelling results suggest that degradation marks (white and black marks) are due to high energy over long periods of partial discharge events that lead to thermal degradation at the oil-pressboard interface.

Heteropolyacids (HPAs) are a group of chemicals that have shown promising results as catalysts during the last decades. Since HPAs have displayed encouraging performance as electrocatalysts in acidic environment, in this project their redox activity in acid and alkaline aqueous electrolytes and their electrocatalytic performance as additives on a bifunctional gas diffusion electrode in alkaline aqueous electrolyte are tested. The results from the electrochemical characterisation of two different HPAs, the phosphomolybdic acid (PMA) and the phosphotungstic acid (PWA) dissolved in acidic and alkaline environment showed that both heteropolyacids demonstrate a redox activity but they also suffer from low stability issues. A series of gas diffusion electrodes were manufactured having PMA and PWA incorporated in their catalyst layer. The electrode support was carbon Toray paper and each heteropolyacid was mixed with Ni to create the catalyst layer of the electrode. From the electrochemical characterisation oF these electrodes in alkaline electrolyte, it was shown that the addition of HPAs enhances the activity of the nickel towards OER and ORR. During the constant current measurements on the manufactured gas diffusion electrodes it was noticed that the electrodes fail after a period of time which could be attributed to the corrosion of the carbon support. In order to find alternative, non-carbon materials to be used as the electrode support, electrochemical characterisation on Magneli phase bulk materials, Magneli spray coated electrodes and PVD coated electrodes was performed. The results from this investigation showed that Magneli phase materials can support electron transfer reactions but their electron conductivity is rather low and it needs to be enhanced. Additionally, it was presented that the Magneli coating protects the substrate over the potential region where OER and ORR take place. Hence, Magneli materials could be used as a support for the bifunctional HPA gas diffusion electrodes.