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The past decade has seen an increase in the capability of small scale Unmanned Aerial Vehicle (UAV) systems, made possible through technological advancements in battery, computing and sensor miniaturisation technology. This has opened a new and rapidly growing branch of robotic research and has sparked the imagination of industry leading to new UAV based services, from the inspection of power-lines to remote police surveillance. Miniaturisation of UAVs have also made them small enough to be practically flown indoors. For example, the inspection of elevated areas in hazardous or damaged structures where the use of conventional ground-based robots are unsuitable. Sellafield Ltd, a nuclear reprocessing facility in the U.K. has many buildings that require frequent safety inspections. UAV inspections eliminate the current risk to personnel of radiation exposure and other hazards in tall structures where scaffolding or hoists are required. This project focused on the development of a UAV for the novel application of semi-autonomously navigating and inspecting these structures without the need for personnel to enter the building. Development exposed a significant gap in knowledge concerning indoor localisation, specifically Simultaneous Localisation and Mapping (SLAM) for use on-board UAVs. To lower the on-board processing requirements of SLAM, other UAV research groups have employed techniques such as off-board processing, reduced dimensionality or prior knowledge of the structure, techniques not suitable to this application given the unknown nature of the structures and the risk of radio-shadows. In this thesis a novel localisation algorithm, which enables real-time and threedimensional SLAM running solely on-board a computationally constrained UAV in heavily cluttered and unknown environments is proposed. The algorithm, based on the Iterative Closest Point (ICP) method utilising approximate nearest neighbour searches and point-cloud decimation to reduce the processing requirements has successfully been tested in environments similar to that specified by Sellafield Ltd.

The PhD thesis with the title “Investigation of several critical issues in screen mesh heat pipe manufacturing and operation” presented hereafter describes work carried out in four main areas. Initially the relevant literature is reviewed and presented, followed by the presentation of theoretical work regarding screen mesh heat pipe fill calculations, heat pipe processing and an investigation into the capillary or lifting height for screen mesh heat pipes. Further, the possibility of tailoring screen mesh heat pipes towards certain applications was investigated and it was found that further work is required in this area to allow a conclusive judgement whether a coarser or finer wick at the wall provides a distinguish advantage over two wraps of a medium coarse type. Within this approach a calculation method for the determination of the optimum working fluid fill of a screen mesh heat pipe based on geometrical parameters of the wick was developed and successfully implemented for the production of the later tested samples. The investigation into the effects of bending on the heat pipe performance, both using single phase flow CFD as well as experimentation, was performed using five different geometrical cases, each with five samples. These were tested in order to minimise the effects of sample variation. The test cases investigated contained the deformation angles of 0° (straight), 45°, 90°, 135° and 180°. During all test cases the orientation of the samples was kept constant at 0° to minimise additional influences like the effects of gravity on the reduction of available power handling capability. The test results show in deviation from CFD results that screen mesh heat pipe performance is significantly affected when bends are introduced and the reduction in power handling capability can be up to nearly 50% of a straight heat pipe value. Finally this thesis advances into the field of water heat pipe freeze thaw and the possibility of screen mesh heat pipes with changed shapes to withstand multiple freeze thaw cycles. It was found that correctly engineered screen mesh copper water heat pipes can be used in applications where they are subjected to multiple freeze thaw cycles. The fluid charge for water heat pipes subjected to these conditions needs to be adjusted in such a way, that accumulation of working fluid in certain areas, regardless of orientation or process variation during filling, is avoided.

Process chains are regarded as viable manufacturing platforms for the production of Microand Nano Technology (MNT) enabled products. In particular, by combining several manufacturing technologies, each utilised in its optimal process window, they could benefit from the unique advantages of high-profile research technologies such as the focused ion beam (FIB) machining. The present work concerns the development of process chains and the investigation of pilot cost-effective implementations of the FIB technology in manufacturing platforms forfabrication of serial replication masters.

The focus of this dissertation is to present novel algorithms and techniques in wireless network systems aiming at performance optimisation. This thesis provides contribution to knowledge on the following topics: (a) sum rate maximisation of two interfering users in an Orthogonal Frequency Division Multiple Access (OFDMA)-based cooperative base stations and (b) event-region detection in Wireless Sensor Networks (WSNs). The first area of work makes contribution on problem of maximising the sum rate of two interfering users, while limiting the received interference at each user. An OFDMA-based system operating in downlink is considered. Comparisons between achieved average spectral efficiency of proposed interference power constraint resource allocation scheme as opposed to achieved average spectral efficiency by non-cooperative Time Division Multiple Access (TDMA) method is provided to prove that the proposed cooperative Base Stations (BSs) scheme outperforms non-cooperative TDMA. The second area of work makes contribution on problem of event region and event boundary detection in WSNs. A new method for classifying randomly deployed sensor nodes over an area of interest into distinctive categories is provided. In this work, a network of spatially distributed and wirelessly connected sensor nodes commissioned to detect two different phenomena, occurring in distant parts of an area of interest, is considered. Analysis on correlation between statistical attributes of received signal distribution at each node and the node’s regional position with respect to two events is provided. Simulation results proves that each node can acknowledge its regional position based only on the statistical attributes of its own environmental readings. This is a promising approach because if only the nodes placed in the close by region of each phenomena report back their reading to the Base Station (BS), as opposed to transmitting entire readings from all nodes, the required bandwidth reduces to be proportional to the size of that event-region only.

International Energy Agency Solar Heating & Cooling (IEA SHC) programme states the fact that space/water heating and cooling demand account for over 75% of the energy consumed in single and multi-family homes. Solar energy technology can meet up to 100% of this demand depending on the size of the system, storage capacity, the heat load and the region’s climate. Solar thermal collectors are particular type of heat extracting devices that convert solar radiation into thermal energy through a transport medium or flowing fluid. Although hybrid PV/T or thermal-alone systems offer some advantages to improve the solar heat utilisation, there are a few technical challenges found in these systems in practice that prevented wide-scale applications. These technical drawbacks include being expensive to make and install, inability of switching already-built photovoltaic (PV) systems into PV/T systems, architectural design etc. The aims of this project, therefore, were to investigate roof integrated solar thermal roof collectors that properly blend into surrounding thus avoiding ‘add on’ appearance and having a dual function (heat absorption and roofing). Another objective was to address the inherent technical pitfalls and practical limitations of conventional solar thermal collectors by bringing unique, inexpensive, maintenance free and easily adaptable solutions. Thus, in this innovative research, unique and simple building integrated solar thermal roof collectors have been developed for heating & cooling applications. The roof systems which mainly based on low cost and structurally unique polyethylene heat exchanger are relatively cost effective, competitive and developed by primarily exploiting components and techniques widely available on the market. The following objectives have been independently achieved via evaluating three aspects of investigations as following: • Investigation on the performance of poly heat exchanger underneath PV units • Investigation on the performance of a Building Integrated PV/T Roof ‘Invisible’ Collector combined with a liquid desiccant enhanced indirect evaporative cooling system • Investigation on the build-up and performance test of a novel ‘Sandwich’ solar thermal roof for heat pump operation These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology, and elucidate the specific conclusions for the practice of such systems. The analysis showed that water temperature within the poly heat exchanger loop underneath PV units could reach up to 36°C and the system would achieve up to 20.25% overall thermal efficiency. Techno-economic analysis was carried out by applying the Life Cycle Cost (LCC) method. Evaluations showed that the estimated annual energy savings of the overall system was 10.3 MWh/year and the cost of power generation was found to be £0.0622 per kWh. The heat exchanger loop was coupled with a liquid desiccant enhanced indirect evaporative cooling unit and experimental results indicated that the proposed system could supply about 3 kW of heating and 5.2 kW of cooling power. Lastly, the results from test of a novel solar thermal collector for heat pump operation presented that the difference in water temperature could reach up to 18°C while maximum thermal efficiency found to be 26%. Coefficient Performance of the heat pump (COPHP) and overall system (COPSYS) averages were attained as COPHP=3.01 and COPSYS=2.29, respectively. An economic analysis pointed a minimum payback period of about 3 years for the system.

This research concerns the development of a risk analysis and mitigation methodology for assessing the impact of uncertainties and complexity of the design requirements arising in new process and product developments in micro and nano manufacturing. The risk analysis methodology integrates different computational approaches for process and product analysis, including the reduced order modelling using design of experiments, risk analysis using sampling-based and analytical methods and optimisation techniques. The integrated risk analysis and optimisation methodology is applied to two applications: (1) the FIB sputtering process control, and (2) a flip chip design. Three different FIB processes using different ion sources were investigated in order to evaluate their process performance with respects to different process parameter uncertainties. A critical comparison of the process capability against the specification limits of different processes was studied. As parts of the research, a new modified computational model is developed for a material sputtering process using focused ion beam (FIB). This model allows the analysis of micro- and nano-structures shape with the FIB machine controlled through multiple beam scans and different beam overlapping. The FIB model related studies also address the modelling requirements for including material re-deposition effects that occur during FIB milling. The model has been validated using an experimental test case. Good agreement is observed between the analytical shape using the model and the actual experiment. The validated model enhances the accuracy of the dwell time prediction. This approach overcomes the dependence of a trial-and-error approach of the process control in nano-manufacturing industry. The proposed methodology is also used to address a design problem of a flip chip design. A novel method for the evaluation of the environmental impact of the flip chip design in a multi-disciplinary optimisation problem is proposed. The goal is to address materials constraints due to environmental regulations and to handle different types of requirements such as the reliability and cost. An optimal flip chip design reliability function is identified. The approach allows electronics manufacturers to consider the environmental impact amongst different design alternatives at an early stage of the design of the product before any real prototyping in order to reduce the total manufacturing life cycle.

The RULES family of algorithms is reviewed in this work and the drawback of the variation in their generalisation performance is investigated. This results in a new data ordering method (DOM) for the RULES family of inductive learning algorithms. DOM is based on the selection of the most representative example; the method has been tested as a pre-processing stage for many data sets and has shown promising results. Another difficulty faced is the growing size of training data sets, which results in long algorithm execution times and less compact generated rules. In this study a new data sorting method (DSM) is developed for ordering the whole data set and reducing the training time. This is based on selecting relevant attributes and best possible examples to represent a data set. Finally, the order in which the raw data is introduced to the RULES family algorithms considerably affects the accuracy of the generated rules. This work presents a new data grouping method (DGM) to solve this problem, which is based on clustering. This method, in the form of an algorithm, is integrated into a data mining tool and applied to a real project; as a result, better variation in the classification percentage and a lower number of rules formed has been achieved.

Surface triangulation is an active area of research due to its wide usage in a range of different computer aided applications, including computer aided design (CAD), manufacture (CAM) and finite element analysis (FEA). Although these applications are used to create, interrogate, manipulate and analyse surfaces, internally they actually approximate the surface geometry using a triangulation and then operate on the triangles, making them triangulation dependant algorithms. However, despite the reliance on the triangulation by the downstream application, there is very little work which has been focused on the inherent affects of the underlying triangulation on the performance or result of the application. Therefore, the impact of the triangulation on the downstream application is still not well known or defined. This thesis investigates triangulation and the downstream effects on the triangulation dependant method of surface flattening. Two novel topics are explored, notably right angle triangulation configurations (RATCs) and axis of minimum principal curvature (AMPC) influenced triangulations, each which was found to have an impact on the triangulation dependant method of surface flattening. Right angle triangles (RATs) are commonly used throughout surface flattening. However, given a set of uniformly sampled points, there are many different ways in which the diagonals can be placed to form a final triangulation consisting of RATs. These different configurations of edges are introduced as RATCs. To investigate the effects of RATCs on surface flattening, three global configurations are proposed; regular, diamond and chevron. In addition, local variations of RATCs are explored by fitting RATCs that best approximated the local Gaussian curvature of the original surface. Also considered is the influence of triangulation developability and its effects on flattening. Developable surfaces should flatten without inducing any area or shape distortion. However, it is shown that the transfer of this developabilty information from the surface to the triangulation can be lost. It is established that skewing the vertices of a triangulation so that no triangle edges followed along the AMPC, causes the flattening to induce distortion. As the shape of a triangulation is defined by its edges, if no edges follow along the AMPC, this means that the triangulation will not inherit this shape characteristic. Therefore, a new method is proposed to triangulate a surface, whilst ensuring that one edge of every triangle follows along the general direction of the AMPC. This thesis also introduces a new efficient and robust parametric trimmed surface triangulation method. Efficiency is gained during trimmed curve tracing by minimising the number of cells processed. Key features are the efficient tracing algorithm and knowledge of orientation of the trimming curves is not required. This approach also minimises the occurrence of degenerate triangles and copes with holes independently of the grid size.

Silicones are used to manufacture finger and wrist joints. However these joints have fractured prematurely in vivo. There is a lack of literature on the mechanical properties of silicones. The aim of this thesis was to investigate the viscoelastic and related properties of elastomers such as silicones and polyurethanes (suggested as a possible substitute for silicones in the implants) and to relate the properties to how an implant may perform in vivo. The viscoelastic properties of medical-grade silicones and Elast-Eon\(^{TM}\)3 were found to depend on frequency in compression. Above a certain frequency, the silicones appeared to undergo a transition from the rubbery to the glassy state. There is a danger that this could lead to the creation of fracture surfaces. The viscoelastic properties of the silicones were not significantly affected by the temperature; pre-treatment of specimens had no appreciable effect on the results. When the viscoelastic properties were measured in tension, there was a significant difference between the properties measured in tension and compression. Accelerated aging significantly increased the moduli of Elast-Eon\(^{TM}\)3, which is of some concern. The cross-link densities of the silicones were measured using a solvent swelling technique and the Flory-Rehner equation. The results showed that this method is useful as an approximate model.