Products are routinely being manufactured with features having dimensions below 50 µm, with consequent of increasing demand for micro-coordinate measuring machines (micro-CMMs) that have stylus systems with tip diameters of 10 µm or less. However, current commercially available micro-CMMs are unable to fulfil this demand reliably. Therefore, with this in mind, the development of a stylus system with a significantly smaller dimension and the potential to fulfil this demand is reported. After an initial review of the current state of the art and the projected needs, this thesis examine in detail the design considerations and analytical modelling of stylus systems. A key factors affecting styli as their dimension is reduced down to the micrometre level are identified and discussed. Based on five important groups of theses influence factors, a new comprehensive set of design rules and analytical models is constructed and the relationship among these rules observed. Maintaining a stylus contact force that reliably detect the measured surface at reasonable operation speeds while having a sufficiently slender and strong stylus shaft become an issue of particular importance. Experimental investigation of a set of prototype micro-styli is used both to demonstrate the effectiveness of the design rules and to compare different manufacturing methods that have been proposed elsewhere. The model underlying the design rules are shown to be generally consistent within existing uncertainty, except for anomalies with one of manufacturing process which is a combination process of Wire Electro-Discharge Grinding (WEDG) and micro-electrochemical (ECM) process for manufacturing of stylus shaft. The surface quality of spherical form deviation of stylus tip is also a major factor in the uncertainty in the scale of measurement. Therefore, the final part of this work develops and demonstrate a new measurement technique for spherical form error of the micro-styli with tip diameter below than 10 µm. This methods employed a coherence scanning interferometry, together with new rotational referencing manipulation system and new technique of data fusion. Practical testing was conducted to 300 µm diameter sphere, with a typical uncertainty below 30 nm being obtained.

The purpose or objective of this research was to study the behaviour of a thermal store for integration with a heat pump. Two different types of heat exchanger, plate heat exchanger (PHE) and serpentine heat exchanger (SHE), were designed and modular units built in the workshop at the University of Warwick. Both heat exchangers were used to study the effect of the mass flow rate, inlet heat transfer fluid temperature, thickness of phase change material (PCM), thermal properties of the PCM etc. on the behaviour of the thermal energy storage (TES). The PCMs selected for this research had phase change temperatures in the range of 50°C-60°C. Thermophysical properties of four different PCMs were determined in the laboratory. PCMs including RT 52, RT 58, Climsel C58 and a eutectic mix of magnesium hexahydrate and ammonium nitrate that are suitable for use with heat pumps were studied using the differential scanning calorimeter (DSC) and hot disk to determine their thermal behaviour when compared to manufactures’ data. The modular units were charged and discharged at different inlet heat transfer fluid temperatures. The PHE experiment was carried out using both RT 52 and RT 58, while the SHE experiments were carried out using RT 52 only. The heat transfer fluid used in the experiments was water. The PHE was made from polypropylene sheet (a polymer material), with channels that carry the water in and out of the store. The SHE was based on a shell and tube concept, designed and used as a thermal store. A MATLAB model was developed based on the enthalpy method using finite difference to study and compare the temperature profile, charge rate and energy stored in the PHE using the thermal properties of RT 52 or RT58 as PCMs suitable for this thermal energy storage application. The MATLAB model was validated for both the charge process and discharge process, with the inlet HTF temperature from the experiment. Experimental results from the SHE experiment are presented for RT 52. The charge rate and energy stored during charging and discharging processes were analysed for different thicknesses of PCM around each PHE module. Results showed that the greater the PCM thickness, the higher the amount of energy stored in the PHE module and the slower it is for the module to charge or discharge. The model was used to evaluate the performance for when the store was fully charged and half charged and the results presented. To increase the capacity of the store for effective use with a domestic heat pump for a specified period of charging during off-peak tariff periods, a thermal store design using 30mm PCM thickness is proposed. With this PCM thickness, a 32kWh thermal store would require about twenty polypropylene sheets. Twenty-two (22) polypropylene sheets arranged in parallel could be charged at 8.89kW, allowing the store to work in conjunction with an 8kW heat pump. This type of PHE storage module could be installed in suitable locations in the home, such as beneath kitchen cabinets or within ceiling voids, which would accommodate the dimensions of the plate heat exchanger. The sheet capacity and number of sheets required for a store of 32kWh was determined for six different PCM thickness using RT 52. A plot of sheet charge rate or store charge rate against the reciprocal of the thickness was produced that can be used to determine the thickness or charge rate is presented. This enables the required store characteristics (PCM thickness and number of sheets) to be determined quickly and easily from the plot or fitted equation.

This work presents the design of a double effect thermochemical heat pump based on the calcium chloride-ammonia and magnesium chloride-ammonia working pairs. The work began with a comprehensive theoretical and literature review of the similar systems which exist in the literature. Once the literature review was done, a large temperature jump experimental rig was built in order to be able to determine the behaviour of the relevant working pairs. Even though the focus of the work is thermochemical reactions, the activated carbon-ammonia pair was first used to validate the large temperature jump rig. The reason for this is that the activated carbon-ammonia pair is better understood compare to the thermochemical reactions. The experiments on the activated carbon- ammonia pair yielded some useful results. The results obtained show that two heat transfer properties (thermal conductivity, k and heat transfer coefficient, h) with physical meaning can be extracted from large temperature jump data. Furthermore, the change in thermal conductivity with the packing density of the adsorbent was investigated. The general trend was one of increasing thermal conductivity as the packing density was increased, the thermal conductivity increased from 0.2Wm‾¹K‾¹ to 0.4Wm‾¹K‾¹ as the packing density was increased from 530kgm‾³ to 705kgm‾³. When the calcium chloride-ammonia and magnesium chloride-ammonia working pairs were investigated in the large temperature jump setup, the kinetic parameters for each respective reaction were obtained. This enabled the development of a dynamic model of a representative thermochemical heat pump based on the aforementioned working pairs. The dynamic model helped to investigate the performance of the heat pump under various operating conditions. The coefficient of performance (COP) and the specific heating power ranged from 1.21 to 1.40 and 40W/litre to 400W/litre respectively depending on the operating conditions.

At present, sustainable manufacturing process has been widely demanded by manufacturing industry to address the financial pressure from increasing energy price and the political pressure from legislation on reduction of environmental impact. The motivation of this research is to reduce the environmental impact caused by high energy demand and consumption on the manufacturing process. This research addresses important issues related to the environmental impact of manufacturing operations. Through a review of literature and industrial practices, the following requirements have been identified: (i) Sustainability performance measures which can be used to effectively identify potential inefficiency, and recommend ways of improvement; (ii) Optimisation of existing manufacturing process which take energy as an additional factor in the optimisation of machining processes; and (iii) Development of new machining processes and technologies that move closer to the theoretical boundaries of energy efficiency. To address the above requirements, this project developed a set of energy prediction models and energy efficiency metrics to measure the energy usage during machining processes. The results show that energy consumption in machining 21/2D milled features can be improved by optimising the use of existing machining processes and by designing new machining processes and technologies. The characteristics of machining operations with energy considerations have been investigated using graphical multivariate data analysis techniques. A direct search method was used to conduct the optimisation procedure. This study showed that energy consumption decreases monotonically as process parameters (depth of cut, width of cut, spindle speed and feed rate) increase, and can be minimised up to 75% for machining Aluminium 7075-T6 by using Haas TM 1CE Vertical milling machine (maximum spindle speed 4,000rpm) without conflicting with cost and time under the constraints of spindle speed, cutting force and surface roughness. Typical optimisation methods have been found which can give similar results, and methods of opening up the reasoning process have been identified which enable practitioners to have more confidence in their results. An optimisation method has been proposed and tested for selecting optimal process parameters for a typical CNC milling operation resulting in the reduction of energy consumption. A scenario-based method has been developed to provide a comprehensive solution for decision makers to solve machining optimisation problems with sustainability considerations. An energy-efficient profiling toolpath strategy has also been developed to improve energy efficiency for 21/2D milled features. It was found that further reduction in energy consumption could be achieved compared to conventional cutting strategies. Finally, the developed methodologies can be integrated as a comprehensive framework into existing machining process improvement procedures to help process planners and manufacturing practitioners to improve the sustainability of manufacturing processes.

Although the performance of twin screw compressors is heavily dependent on the rotor clearances within them, chamber models, used as design aids, allow for the specification of their magnitude and distribution but do not account for how these may vary during operation, as a result of internal temperature changes caused by the compression process. A validated procedure has therefore been developed to enable a chamber model to predict compressor performance, while including the effects of rotor and casing distortion resulting from dependant thermal effects. This has been achieved by the use of surface boundary mapping to calculate the rotor and casing temperature exposure within the compression chamber resulting from initial performance estimates. These detailed temperature distributions are processed analytically using appropriate assumptions that allow calculation of component temperatures and thermal growth. A program for calculation of leakage area curves has been adapted to support locally calculated variations in clearances. These updated area curves can then be fed back into the chamber model in an iterative procedure to simulate performance with thermally distorted clearances. The inclusion of thermal clearance corrections generally improved the accuracy of the chamber model when predictions from it were compared with test results over a wide range of operating pressures and temperatures. Furthermore, this work was found to be applicable in the evaluation of the interlobe clearance distribution between the rotors. Predicting clearance distortions and likely areas of rotor to rotor contact at a particular operating duty allows clearances to be optimised for the correct balance between performance and reliability; the results thus obtained were supported by findings from available test and tear down results.

In recent years there has been an increasing interest in power generation using small-scale concentrated solar power units. Currently, photovoltaics are the main commercialised technology thanks to their low capital cost. However, their relatively low efficiency and power density has motivated research on the application of thermal engines. Dish-Stirling systems achieve reasonable efficiencies, but are relatively expensive and unreliable because of their technical complexity. The reliability of micro gas turbines and their potentially lower costs has motivated the current research, which is part of the EU funded OMSoP project, to study the thermo-economic performance of a micro gas turbine (MGT) engine coupled with dish concentrators in order to achieve suitable efficiency at low cost. To achieve this goal a system design, which takes into account the state of the art technology, is required to achieve an acceptable efficiency with minimised capital cost to promote dish-MGT systems in the market. An important issue to be addressed is to consider the effect of system design parameters on dish-MGT performance under the considerable variations of the solar irradiance. A computational model for pure solar dish-MGT systems has been developed, which combines the cycle analysis of the MGT with component models to perform design point performance simulation, generate component performance maps and perform off-design performance simulation. The method has been proven to be quick and effective, particularly in terms of using minimal data and providing the component performance maps for off-design simulation. Different strategies which can be applied to pure solar dish-MGT systems are examined and novel concepts have been proposed to increase the generated electricity. The computational model has been coupled with an up to date economic model which was specifically developed through the OMSoP project for dish-MGT systems. The integrated model is coupled to an optimisation platform to find system designs which lead to optimal thermo-economic performance for a 5kWe system. Then the optimisation has been extended over the rated power of 5-30kWe to find the power rating which results in the minimum cost of generated electricity by the dish-MGT systems. The proposed concepts for the control and operation of the dish-MGT systems are shown to be advantageous for increasing electricity production and dealing with the variations of power demand. The results demonstrate the potential of pure solar dish-MGT systems to achieve economically competitive electricity when the economy of scale of these systems is taken into account.

The advances in Fuel Injection Equipment have increased the injection and combustion efficiency, but have also increased the possibility of failure. Recent studies have identified various types of deposits of different components, such as fuel filters, injector nozzles etc. In this regard, white light scattered from the internal flow structures along with both elastic (Mie signal) and inelastic light (fluorescence) from the external sprays were synchronously captured by two separate high-speed cameras. The part of the present work was based on the experiments conducted by Jeshani Mahesh and post-processed by the author of this dissertation. The analysis performed suggested potential deposit formation mechanisms inside diesel injector nozzles considering the operating conditions of the injection system and the physical properties of the fuels. The observed circumferential bubble motion at the late stages of the needle return and post-injection, has been proven to generate low and high-pressure gradients which govern the bubble movement inside the nozzle passages. In engine conditions, the inward bubble movement inside the passages is believed to be the mechanism for the admission of hot combustion gases inside the nozzle geometry. The reaction of these hot gases with the liquid fuels is believed to produce deposits inside the FIE. The LIF-Mie obtained ratios provided an insight into the external spray drop-sizing and atomisation characteristics. The undertaken analysis revealed a strong link between the spray drop size and the physical properties of the fuels. It was also shown that both the needle lift and the operating conditions played a decisive role in the atomisation process and that an increase in rail pressure led to the formation of smaller droplets, while an increase in viscosity and surface tension led to larger droplets. The size of the spray droplets during the early and late stages of the needle lift was larger in relation to the maximum needle lift, due to the synergy of flow chocking and various types of cavitation (needle cavitation, string cavitation). The final section of this analysis involves the phenomenological study of the emerging sprays based on the LIF spray data. This study that the liquid core of the sprays was destroyed either inside the nozzle passage or in the vicinity of the nozzle exit. The obtained results referred to the LVF of different regions of the sprays as a function fuels’ properties, needle lift and rail pressure. A similar analysis was based on data obtained from an improved experimental setup. The white light scattering was replaced by LIF to enable a quantitative analysis in terms of Liquid Volume fraction inside the nozzle passage. To the best of the author’s knowledge, such measurements were attempted for the first time and there are no similar results in the available literature. The spray results obtained came to an agreement with the afore-mentioned findings, validating the experimental and processing methodologies. The inelastic scattered light captured from the structures were formed inside a real-size nozzle passage reflected the effects of the fuels’ physical properties, needle lift and rail pressure. The results obtained referred to the relative LVF of the flow inside the nozzle passage. An increase in rail pressure led to lower relative LVF or SFLVF (term introduced for the purposes of the present work), as a result of enhanced cavitation phenomena. Additionally, the SFVLF of lighter fuels was lower compared to heavier fuels, due to intensive cavitation, which reduced the amount of liquid fuel in the hole. The obtained results also confirmed the argument suggesting the spray asymmetry to be associated to the geometric cavitation formed in the vicinity of the nozzle entrance.

The weakness of a conventional Eulerian soot model in capturing primary soot size and its inability to access individual soot information led to the development of a Lagrangian soot tracking (LST) model as reported in this thesis. The LST model aimed to access the history of individual soot particles and capture the soot concentration and primary soot size distribution in high pressure spray flames, under diesel-like conditions. The model was validated in a constant volume spray combustion chamber by comparing the predicted soot volume fraction (SVF), mean primary soot diameter and primary soot size distribution to the experimental data of n-heptane and n-dodecane spray combustion. The inception, surface growth and oxidation models were adopted and modified from the multistep Moss-Brookes (MB) soot model, which was used in this study as the representative of Eulerian soot model. Parametric studies were carried out to investigate the influence of soot surface ageing and oxidation rates on the overall soot formation. Following the parametric study, the developed LST model which incorporated surface ageing effect and higher oxidation rates was implemented to investigate the effect of ambient oxygen and density on soot morphology in n-heptane spray flame. The LST model was shown to have better primary soot size prediction capability while still maintaining comparable performance in predicting SVF with respect to its Eulerian counterpart. The SVF distributions predicted by the LST model qualitatively correspond to the experimental results despite the peak soot location being predicted further downstream by 30 mm. The primary soot size distribution predicted by the LST model had the same order as the measured primary soot size distribution despite predicting larger soot size. The presence of surface ageing factor had a significant effect on the primary soot size distribution whereas only a slight effect on the SVF profile. A maximum soot size reduction of 48% was obtained when incorporating surface ageing effect. The consideration of surface ageing effect led to smaller primary soot size predicted and better agreement with the measured primary soot size distribution. The peak and mean primary soot sizes increased with increasing ambient density, from 14.8 kg/m3 to 30 kg/m3, at the core of spray jet. Meanwhile, the decrease in oxygen level from 21% to 12% at an ambient density of 14.8 kg/m3 caused a non-monotonic effect on the primary soot sizes at the core of spray jet. Trivial differences were predicted when oxygen level decreased from 21% to 15%. However, a significantly smaller primary soot sizes were predicted when oxygen level decreased further to 12%. In addition to net growth rates, soot cloud span and soot age were also found to play an important role in evolution of primary soot size. An increase in ambient oxygen and density resulted in a more upstream first-soot location. The effect of ambient density on soot age was not significant, whereas a lower oxygen level resulted in a longer soot age. A maximum soot age of 0.50 ms was obtained for both 21% and 15% O2 cases at both density levels. As oxygen level decreased to 12%, the maximum soot age increased to 0.58 ms due to lower combustion temperature. Overall, the LST model was shown to perform better in predicting primary soot size and can access information of individual soot particles which are both shortcomings of the Eulerian method. In addition, the LST model was also demonstrated to be able to predict soot age. Apart from playing a role in determining primary soot size, soot age can also serve as a useful parameter to answer various fundamental questions, such as when and where soot particles grow to a certain size, and help in the understanding of fundamental soot processes. Optimisation of the model and extension of its capability to capture soot aggregate structure, size and fractal dimension will be of interest in the future.

Advances in microfluidic research have improved the quality of assays performed in micro-scale environments. Improvement of liquid handling techniques has enabled efficient reagent and drug use while minimising waste. The requirements for the applied techniques vary with applications and a custom integrated liquid handling solution was developed to accomplish some of these applications with minimal changes to the system. It is desirable to employ this technology to neuroscience research that requires a fluidic system that can test theories of reinforcement learning in neuronal cultures. An integrated system is therefore required to implement transport and manipulation of media and drugs loaded in a microfluidic device. One requirement for such an integrated system for liquid handling is a transport mechanism to deliver reagents and nutrients to cultures. A liquid flow control system is required to allow precise and timely control of flow rates through a microfluidic device. This can be extended to enable more sophisticated drug delivery approaches like gradient generation, spatial drug distribution and high temporal resolution of the drugs delivered. Another requirement for an integrated system is a liquid loading system that is capable of inserting specified drugs into the flow line. Such a loading system would allow any number of drugs to be loaded during an experimental process to the microfluidic device containing cells as part of an assay. The integration of these systems will allow researchers take advantage of the combined systems. Software development process should also be undertaken to improve the modularity of the integrated system so that hardware changes have marginal effects on the system operation. The project scope was the development of these liquid handling systems as well as their integration in hardware and software to enable their spatio-temporal drug delivery to neuronal cultures in microfluidic devices. The approach was to optimise performance of custom liquid handling system which was developed to realise fast flow rate changes within 1 second interval. Macro- and micro-scale solutions have been investigated in order to realise effective off-chip liquid loading capabilities. Emphasis has been placed on ease of use, modularity, rapid prototyping and precision. A commercial autoloader was identified as a starting point for sequential drug delivery. This was characterised for suitability and the constraints with this setup was used to identify additional requirements for the development of a novel sequential liquid injection system. The design process of the novel liquid injection system was unable to realise a working system due to mechanical and operational challenges encountered. A modular on-chip liquid manipulation system has been investigated and proposed to realise the sequential injection requirements. Rapid prototyping techniques that can promote ubiquitous microfluidic applications have been identified and verified. An integrated liquid manipulation system has been developed using the commercial autosampler that enables sequential loading of agonists into the microfluidic device as well as reliable chemical signalling of the loaded drugs by switching flow rates of the inputs to the device. This system will be beneficial towards research of other cell types within other research fields requiring similar functionality.

This thesis examines the rheological behaviour and film formation of greases and oils under elastohydrodynamic (EHD) conditions. It approaches the lubrication of non-conforming contacts from tribological as well as from dielectric point of view. The experimental work was carried out on a point contact formed between a ball and the flat of a disc, which was either transparent, for optical interferometry study or steel in order to evaluate the conditions in real-life machine components. In the second case electrical capacitance method has been employed to study film formation. The experimental equipment has also been adapted to study the starvation behaviour of grease lubricants in point EHD contacts under vibrations. Dielectric properties of lubricants have been studied in static conditions and correlated to their performance in EHD conditions. The dielectric constant of greases indicates in general higher value than corresponding base oils and the dielectric relaxation time of greases is proved to be shorter. It has been found that in EHD conditions higher-polar greases show higher shear stress, while the dielectric constant of the lubricating film decreases with increasing contact pressure. The effect of three parameters upon grease EHD films was evaluated: operating speed, load and vibration of the contact. The results showed that greases possess an intrinsic time to starvation related to the operating speed but independent of the exerted load. The results also showed that a high speed was not necessarily associated with the high likelihood of occurrence of starvation. The vibration tests revealed that the lateral motion perpendicular to the rotating direction helped maintain the inlet region flooded and, under oscillations, starvation of the contact seems to never occur. This would suggest that machine elements such as rolling element bearings could operate under the fully flooded conditions as vibrations are almost inevitable in any machinery. Finally, the cavitation phenomenon was also investigated and found that the rheological model of greases could be predicted from the observation of the cavity pattern.