The advances in micro engineering and especially micro products and micro components with functional micro and nano structures / features are directly dependent on the advances in manufacturing technologies for their scale up production. Micro injection moulding is one of the key technologies for cost affective serial production of micro components. In this thesis, the process capabilities and constraints of this technology were studied systematically. More specifically, new tool making process chains and various process factors affecting the micro injection moulding process were investigated. The manufacturing capabilities of this technology were further analysed by investigating the filling behaviour of micro cavities, the influence of air in micro cavities and the forces occurring during the demoulding stage. Chapter 2 of this thesis reviews the slate of the art in micro tooling and micro injection moulding. In Chapter 3 an advanced condition monitoring system was developed to better understand the behaviour of the injection moulding process. In particular, cavity pressure sensors were utilised to analyse interdependences between process conditions and key characteristics of cavity pressure curves. Chapter 4 investigates the influence and effects of air inside micro cavities. A design of experiments’ study was carried out to identify process settings for achieving an optimum filling of micro cavities In particular the flow length inside the cavity was investigated to judge about the process performance. Next, the demoulding stage of the injection moulding cycle was studied in Chapter 5. In particular, ejection forces were analysed to investigate the influence of different process settings on demoulding behaviour of polymer parts. This is especially important in order to avoid any part damage during demoulding. In Chapter 6 micro stereolithography was used to fabricate mould inserts for micro injection moulding. Experiments were carried out with such mould inserts, and the tool life in relation to process settings for both the manufacture of the inserts and their replication performance, was studied systematically. Finally, Chapter 7 summarises the main conclusions and contributions to knowledge of this research. Also, future research directions in the area of micro injection moulding are proposed and briefly discussed The main findings of this research can be summarised as follows: • Indirect measurement methods can be utilised to monitor cavity pressure conditions in micro injection moulding and it was shown that Pmax, Pwork and Prate were dependent on the materials and processing conditions. • The performance of the u-IM process can be improved by understanding the effects of V1 and air evacuation on Qmax, Q, and the part flow length. High u-IM process settings and a limited venting through the primary split line have a significant impact on the filling performance. The u-IM process performance can be improved by incorporating secondary vents and by applying vacuum methods for air evacuation. • Pmax, Pwork and Fe max were dependent on the processing conditions and there is a direct correlation between cavity pressure and demoulding force. The position of the pressure sensors is important, but the readings of both sensors correlate. The holding pressure has the highest impact on the maximum demoulding forces. Rapid tooling can be applied successfully in u-IM and offers a faster, cheaper and highly flexible manufacturing route for producing prototypes in the final material. Only the uSL inserts produced with a layer thickness of 20 um (less undercuts) survived during the demoulding stage. The best results were achieved with PP, followed by PC. ABS polymer parts couldn’t be replicated successfully.

Machine learning programs can automatically learn to recognise complex patterns and make intelligent decisions based on data. Machine learning has become a powerful tool for data mining. A great deal of research in machine learning has focused on concept learning or classification learning. Among the various machine learning approaches that have been developed for classification, inductive learning from examples is the most commonly adopted in real-life applications. Due to non-uniform data formats and huge volume of data, it is a challenge for scientists across different disciplines to optimise the process of knowledge acquisition from data with naïve inductive learning techniques. The overarching purpose of this research is to develop a novel and efficient rule induction algorithm a learning algorithm for inducing general rules from specific examples that can deal with both discrete and continuous variables without the need for data pre-processing. This thesis presents a novel rule induction algorithm known as RULES-8 which utilises guidelines for the selection of seed examples, together with a simple method to form rules. The research also aims to improve current pruning methods for handling noisy examples. Another major concern of the work is designing a new heuristic for controlling the rule formation and selection processes. Finally, it concentrates on developing a new efficient learning algorithm for continuous output using fuzzy logic theory. The proposed algorithm allows automatic creation of membership functions and produces accurate as well as compact fuzzy sets.

Applications of rapid prototyping are expanding to new domains. This is particularly true of the selective laser sintering (SLS) process. In order for that process to be competitive and become a strong candidate for new applications, such as rapid manufacturing, the material used needs to be improved. The aim of the work presented in this thesis was to develop a new composite material made up of Polyamide 12 (a common SLS material) and cement, an inexpensive additive, for the purpose of improving the mechanical properties, as well as reducing the cost of the sintered components. An experimental study was conducted of the thermal properties of the cement-Polyamide 12 composite material with different proportions of cement and Polyamide 12. The purpose of the study was to determine optimal SLS parameters to produce good quality fabricated SLS specimens. The research also involved an experimental investigation of the mechanical properties (Young‟s modulus, tensile, flexural, compression and impact strengths, and density) as a function of the proportion of cement additive to Polyamide 12. Finally, a method of quickly and inexpensively producing test specimens by casting instead of using SLS was developed and experiments conducted to demonstrate the similarity in properties between cast and SLS specimens. II This research has shown that adding cement to Polyamide 12 yields a composite material that enables the production of sintered specimens with mechanical properties that are superior to those of pure Polyamide 12 specimens. As cement is much cheaper than Polyamide 12, the composite material is also obviously less expensive than pure Polyamide 12.

This thesis reports experimental and theoretical analyses to study the heat generation and partition between contacting bodies under rolling/sliding elastohydrodynamic (EHL) point contact. A twin disk test rig was re-commissioned and used for the experimental work. 76 mm diameter crowned, super-finished test disks, fixed on parallel shafts, were used in the experimental EHL tests. In each disk, 6 thermocouples were installed to measure the temperature during sliding/rolling contact under EHL conditions. In addition, ceramic washers were fixed on the plane sides of each disk to minimize heat transfer over those surfaces. A Labview data acquisition system was built for acquiring data from the sensors installed on the rig. The EHL experimental results show the fast disk has significantly higher bulk temperature than the slow disk. A transient two dimensional numerical model was constructed to calculate the average circumferential temperature distribution within the disks using three thermocouples as a boundary condition. The heat partition factor,  , and convection heat transfer coefficient, h, were varied systematically in the model. A linear relationship between  and hf for the fast disk and 1- and hs for the slow disk were obtained. These two linear relations were related together by the variation of h with the rotational speed. Over the approximately steady state condition, the calculated  using this approach was in the range of 0.65 to 0.77 for 32 EHL tests at different loads and sliding speeds. This means that the majority of heat is conducted to the fast disk, which is compatible with the previous findings. In order to carry out transient modelling, the unloading mechanism was developed to ensure rapid disk separation. This improved the temperature trend in the cooling phase. In addition, a microswitch was used to give accurate monitoring of the disks contacting and separation. The thermocouple arrangement within the disks and their installation technique were assessed and developed. An immersion test in a hot oil bath was used to test the thermocouples dynamic response. This test was modelled, and the results showed significant lag in the measurements. It was concluded that a system identification method is required to identify the dynamic characteristics of the temperature measurement system in order to compensate for time lagging Extensive studies were carried out to determine the cause behind some of the experimental uncertainties. It was found that the most likely reason behind these uncertainties is the contact pressure variation along the disk-shaft interference fit, which would result in significant thermal conductance variation. The traction force measurement within the EHL contacts has shown broadly linear increase with increased load at constant sliding speed. This indicates a constant coefficient of friction at constant sliding speed. The results also showed that the coefficient of friction decreases as the sliding speed increases.

Surface-mounted heat flux sensors have been used in the intake port of a fuel injected, spark ignition engine to investigate heat transfer between the surface, the gas flows through the port, and fuel deposited in surface films. This investigation has been carried out with a single-cylinder engine on which the cylinder head is from a production four valve per cylinder engine with a bifurcated intake port. The objective has been to establish how engine operating conditions affect trends in surface heat transfer rates both with and without fuel deposition on the surfaces, and to relate these to the mechanisms involved in the transport of fuel into the engine. The effects on these mechanisms of injector type and fuel characteristics have also been studied. Fuel transport has been characterised using the τ and X parameters, and experimental studies have been carried out to examine these for fully-warm and warm-up engine operating conditions, with a range of injector types representative of those currently used in service. This data has been compared to the results of a photographic study of the fuel distribution pattern produced by each injector type, and these combined results used to decide upon suitable positions within the inlet port for the heat flux sensors. The dynamic response characteristics of the surface-mounted heat flux sensors have been determined, and measured heat flux data corrected accordingly to account for these characteristics. Details of the model and data processing technique used, are described. Corrected intra-cycle variations of heat transfer to fuel deposited have been derived for engine operating conditions at 1000 RPM covering a range of manifold pressures, fuel supply rates, port surface temperatures, and fuel injection timings. Both pump-grade gasoline and isooctane fuel have been used. The influence on heat transfer rates of the deposited fuel and its subsequent behaviour has been examined by comparing fuel-wetted and dry-surface heat transfer measurements. With both fuel types, the heat transfer rate to the fuel reaches peak values up to around 50 kW/m2 during the engine cycle, and is typically 5 kW/m2 on average in regions of heavy fuel deposition. The effects of operating conditions on the magnitude and features of the heat flux variations are described Integration of this heat flux data has provided values of heat transfer per cycle, allowing direct comparisons of operating condition and injector type effects to be made. For dry-port conditions heat transfer per cycle varies between 0 and 300 J/m2 depending on location, towards the surface at low temperatures and away from the surface at fully-warm conditions. During warm-ups with fuel deposition, as coolant temperature increases from 0 to 90°C, values of heat transfer to the fuel typically increase from 300 J/m2 to 1000 J/m2. For a given coolant temperature, heat transfer values generally increase as manifold absolute pressure (MAP) is lowered or fuel flow rate increases. The effect of fuel deposition on heat transfer has been characterised by a function of MAP, fuel flow rate and coolant temperature. When running on isooctane fuel the heat transfer measurements were made using a heat flux gauge bonded to the intake port surface in the region where highest rates of fuel deposition occur. Heat transfer changes are consistent with trends predicted by convective mass transfer over much of the range of surface temperatures from 20°C to 100°C. Towards the upper temperature limit, heat transfer reaches a maximum limited by the rate and distribution of fuel deposition. The inferences drawn from the isooctane results are discussed and related to characteristics observed when gasoline is used.

Gas-liquid flow commonly occurs in oil and gas production and processing system. Large diameter vertical pipes can reduce pressure drops and so minimize operating costs. However, there is a need for research on two-phase flow in large diameter pipes to provide confidence to designers of equipments such as deep water risers. In this study a number of experimental campaigns were carried out to measure pressure drop, liquid film thickness and wall shear in 127mm vertical pipe. Total pressure drop were studied systematically through a data bank of 600 experimental runs. Magnitude and directional wall shear stress measurements have been made selectively using commercial non-directional probes and directional hot films. The latter were produced at Nottingham University during this study. Experimental data on liquid film characteristics were obtained by measuring total pressure drop, wall shear stress and film thickness simultaneously. In addition, the data were supported by some high speed video images through a visualization campaign. The pressure drop profile (time-averaged total pressure drop as a function of gas flow rate) introduced is visibly different from that for smaller pipes as it does not show a clear minima in the chum-annular transition region and not in both bubble-slug and slug-chum region. No completely unidirectional upward flow has been observed in the range of the conditions studied from the results of directional wall shear stress measurement which provided information on both time-varying and time-averaged wall shear stress. A condition of zero wall shear stress not reached. However, there was a minimum observed in the plot of mean wall shear stress against dimensionless gas velocity. This minimum occurred at the same dimensionless velocity for the present data at those from small diameter pipes. The change in the direction of the liquid film also supported by the measurements of local film thickness and high speed video images which have shown waves move both upward and downward and not purely in axial direction.

The use of remote teach controls for programming industrial robots has led to concern over programmer safety and reliability. The primary issue is the close proximity to the robot arm required for the programmer or maintainer to clearly see the tool actions, and it is feared that errors in robot control could result in injury. The further concern that variations in teach control design could cause "negative transfer" of learning has led to a call for standardisation of robot teach controls. However,at present there is insufficient data to provide suitable design recommendations. This is because previous researchers have measured control performance on very general, and completely different, programming tasks. This work set out to examine the motion control task, from which a framework was developed to represent the robot motion control process. This showed the decisions and actions required to achieve robot movement, together with the factors which may influence them. Two types of influencing factors were identified: robot system factors and human cognitive factors. Robot system factors add complexity to the control task by producing motion reversals which alter the control-robot motion relationship. These motion reversals were identified during the experimental programme which examined observers' perception of robot motion under different conditions of human-robot orientation and robot arm configuration. These determine the orientation of the robot with respect to the observer at any given time. It was found that changes in orientation may influence the observer's perception of robot movement producing inconsistent descriptions of the same movement viewed under different orientations. Furthermore, due to the strong association between perceived movement and control selection demonstrated n these experiments, no particular differences in error performance using different control designs were observed. It is concluded that human cognitive factors, specifically the operators' perception of robot movement and their ability to recognise motion reversals, have greater influence on control selection errors than control design per se.

Machining defects induced by conventional drilling of carbon fibre reinforced plastics (CFRPs), of which the most concern is delamination damage both to the surface of the component and to the machined surface of the hole, usually occur due to the heterogeneity and anisotropic properties of the material. Among previous research work on conventional drilling of CFRPs, attempts to minimise delamination damage have focused on the optimisation of tool material, geometry and cutting parameters. Although the application of cryogenic cooling has been shown to improve performance in metal machining, there has been little research work reported on its application to conventional drilling of CFRPs. Therefore, the objectives of this research were to evaluate the application of cryogenic cooling, for which CO2 was used as the main cutting fluid, in conventional drilling of CFRPs and present a detail explanation of the effect on machining performance and mechanism associated with cryogenic machining of these materials. Drilling experiments with liquid nitrogen (LN2) pre-cooled tools, with CO2 cooling and when machining dry at room temperature were performed on CFRPs (carbon/epoxy) plaques using TiAlN and diamond coated solid tungsten carbide drills. The performance evaluation was based on measurement of thrust force, tool wear and delamination damage to the entry/exit of the hole and internal damage to machined surface of the hole. Cutting temperature and characteristics of machined surface (fracture behaviour of carbon fibres and epoxy matrix) produced when drilling with cryogenic cooling and dry at room temperature were also investigated. In this research, it was found that application of cryogenic cooling (LN2 pre-cooling and CO2 cooling) to conventional drilling of CFRPs resulted in an improvement in machining performance with respect to quality of the hole. Less exit delamination damage and internal damage to machined surface of the hole were produced when machining with cryogenic cooling compared to room temperature dry drilling. However, the use of cryogenic cooling in conventional drilling of CFRPs did not improve machining performance with respect to cutting forces and tool wear. In fact, it resulted in higher thrust force and average flank wear compared to machining dry at room temperature. The reduction of delamination and internal damage and the increase of thrust force and rate of tool wear were found to be due to the higher abrasiveness, strength and stiffness of CFRP plaques that were retained during drilling with cryogenic cooling. The cutting temperature was shown to be lower than room temperature dry drilling due to the more effective removal of heat from the cutting zone. It was shown that the cutting temperature was reduced by 14-27% when drilling with cryogenic cooling, for which the use of a CO2 cooling system provided the highest cooling ability, at a cutting speed and feed rate of 100 m/min and 0.06 mm/rev respectively. It was shown that drilling with cryogenic cooling resulted in a more brittle fracture behaviour and less thermal softening of the epoxy matrix in CFRP plaques compared to that produced by room temperature dry drilling. This indicates higher strength and stiffness of the epoxy matrix that were retained during drilling with cryogenic cooling hence resulting in higher abrasiveness, strength and stiffness of the plaque due to more rigid support of the matrix. Since the drilling-induced damage, which was shown in previous research work to degrade the mechanical properties and performance of CFRP components, was reduced, the application of cryogenic cooling can therefore be beneficial when implemented in conventional drilling of CFRPs to improve productivity. However, tool material has to be optimised to compensate with shorter tool life due to increased rate of tool wear. Although no significant difference in thrust force was produced when drilling with CO2 cooling and when drilling with a LN2 pre-cooled tool at the same cutting speed and feed rate, less damage to the machined surface was produced when drilling with CO2 cooling. This was found to be due to higher capability in reducing the cutting temperature than LN2 pre-cooling of the tool. Therefore, the application of cryogenic cooling by continual supply of CO2 (or LN2) is more preferable and more practical to be implemented in the production process in industry than cryogenic pre-cooling of the tool.

The original contribution to knowledge made by this research work is demonstrating the benefits of differentially fed balanced transmit antenna in modern communication system. Extensive experimental studies have established the fact that a true differential amplifier feeding a balanced antenna offers higher linearity and lower distortions compared to the single ended feeding technique, even while using the same amplifier. With continuing advancements in personal communications in this era of digital economy, the demand for wireless connectivity has grown radically, resulting in stringent performance requirement for RF components. Differential circuits are preferred choice in RFIC design due to its good noise immunity and low distortion characteristics. But it is observed that single ended PAs and LNAs are used for the feeding part because of the antenna industry’s tendency to stick to conventional 50Ω interface. Therefore, differentially fed transmit balanced antenna is an area of current research, which has been studied in this thesis. The study was set out with a review of the state-of-the-art in active integrated antennas. Following that, the ground plane influence on antenna radiation pattern was explored and novel techniques to compensate the effects were presented. It was observed that the current flow in a coaxial cable also affects radiation pattern. Hence, a novel method was proposed to measure wireless devices in the anechoic chamber eradicating the need of any cable attachments. Broadband differential amplifiers were then reviewed with a view to feed balanced and unbalanced antennas for demonstrating the potential of differential feeding technique over the conventional one. The amplifier with differential output interface exhibited higher gain and linearity in both bench test and radiated power test. Further improvement in linearity was reported by lowering the output resistance of the amplifier. Afterwards, a broadband antenna with stable radiation pattern and impedance was designed to carry out radiated harmonic measurements, which illustrated that the fully differential output configuration possesses significantly lower harmonic distortion. All these measurement results have suggested that balanced antenna fed by differential amplifier can be the best solution for applications demanding higher output power, greater linearity and lower distortion. Therefore it is recommended to re-evaluate the idea of power amplifier and antenna interface in RF front-end designs.

Metal-on-metal (MOM) total hip replacement is an artificial hip joint has been used to replace damaged or diseased natural joints. MOM studies have demonstrated severe complications due to metal wear debris in tissues adjacent to the implants. Reducing the wear rate and operating with full film lubrication could reduce these problems; a better understanding of the lubrication mechanisms is also relevant to other hard bearing materials such as ceramics or new metal alloys. Ball-in-socket MOM contacts were analysed using the Abaqus Finite Element package to simulate dry contact between the acetabular cup and the femoral head. Different cup thicknesses of 4, 6, 8, and 10 mm were considered using a polyurethane foam block support system. Elastohydrodynamic lubrication (EHL) analyses were developed for the contacts using three different approaches to specify the contact. These were (i) A simple model based on the radii of relative curvature, (ii) An equivalent contact model developed so that its dry contact area and maximum pressure replicated the values obtained from the FE analysis, and (iii) A modified version of (ii) that also ensured equivalence of the gap shape outside the contact area. Published in vivo information for the hip joint contact forces over the walking cycle was used to specify the operating conditions for the EHL analysis. III This was achieved by developing techniques to transform the in vivo information to provide load direction and kinematic information relative to the nominal contact point between the components. The analysis method was found to be effective for all points of the walking cycle for cases where the cup thickness exceeded 5 mm and modelling approach (ii) was identified as satisfactory. For a cup thickness of 4 mm, membrane action began to emerge in the FE analyses so that such contacts behaved in a different way.