This thesis presents the application of coplanar circuit analysis in the design of compact single-feed circularly polarised (CP) and linearly polarised (LP) microstrip patch antennas. A CP nearly square patch antenna and a CP truncated corners square patch antenna are designed. Also a LP U-slot rectangular patch antenna is designed. In order to obtain a faster computational run-time, coplanar circuit analysis and segmentation method are applied for the impedance calculations. The coupling and self impedance formulas for both rectangular and right-angled isosceles triangular segments are given. Explicit formulas for the coupling impedance between a perimeter port and a probe port, and also the probe self impedance on both of these segments are new and are derived in detail. A CP nearly square patch antenna is designed using both the cavity and equivalent circuit models. New and simple design equations are derived to determine the dimensions of the patch with a feed in any given position. For a microstrip feed offset from a corner of the patch, the area of perturbation segment is increased which reduces the effect of manufacturing errors. A simple matching network consisting of a short length of microstrip line is designed to achieve a more compact form of the matched antenna. The results obtained from both models are good agreement. A CP truncated corners square patch antenna with a microstrip feed offset from the centre is presented. In previous work the design is a feed along the centre line and the areas of the deleted segments are very small so the performance of the antenna is very sensitive to manufacturing errors. Hence an offset feed is proposed in order to increase the perturbation area and so reduce the effect of the manufacturing errors. The segmentation method is used for which a new explicit matrix input impedance formula is derived. The impedance formula requires a computer run time less than half that required by simulation (full-wave software, Ansoft Ensemble). The change in area of the perturbed segment and input impedance with the microstrip offset feed position is examined. A compromise offset feed position was chosen so as to maximise the area of the perturbation segment and achieve good impedance matching for a compact antenna structure. A LP probe feed U-slot rectangular patch is designed and the input impedance is determined. A set of initial design equation is used to produce a first-pass design. In applying segmentation method a new explicit input impedance formula for the antenna is derived. The basic system of eleven coplanar circuit equations is reduced to seven equivalent circuit equations from which the explicit impedance formula is derived. The dimensions of the patch are adjusted to give good impedance matching. In respect of computational efficiency, the run time of the new matrix input impedance formula is at least 10 times faster than is required by simulation. A thicker substrate is also used in order to improve the bandwidth. The predicted, simulated and measured results of the above three compact patch antennas are in good agreement. Mathcad programming is used to implement the design calculations of the compact patch antennas.

In this thesis the development of light emitting diodes (LED) is reviewed. The emphasis is put on devices emitting at the blue region of the spectrum. The physical characteristics of these devices are considered. The main interest is based around the ability of blue LEDs to generate nanosecond range optical flashes. The fast pulsing electronic circuits capable of driving the devices are also reviewed. These are complemented by the potentially exploitable techniques that could provide further benefits for required fast optical pulse generation. The simple, compact and inexpensive electronic oscillator for producing nanosecond range pulses is developed. The circuitry is adapted for generation of pulses necessary to switch on and assist with the turn off of blue InGaN based LEDs. The resulting nanosecond range blue optical pulses are suitable for, but not limited to, the calibration of scintillation counters. These devices used in neutrino detection experiments could provide a better understanding of cosmology and particle physics.

In recent years, there has been growing interest towards integrating industry into the teaching and learning processes. This is due to many factors including increased concerns about the mismatch between the skills and abilities of the talent pool, strengthening partnership and improving quality of engineering education. Thus, greater emphasis on the teaching and learning processes to enhance the students’ learning experience leads to the university-industry partnership to the forefront interest of the university. On the other hand, exclusion of industry’s engagement in the teaching and learning processes have been identified as the main source of chronic criticism on the higher engineering education segment in recent years. This study demonstrates a research model that hypothesised the influence of teaching and learning domains on the university-industry partnership towards enhancing the learning experience of the engineering students. Using the structural equation modelling (SEM), the hypothesis was tested on the primary data collected from 212 communities of the industry. Furthermore, the study investigated the preference of industry on the type of linkages to foster university-industry partnership using analytical hierarchy process (AHP). The results revealed that nine out of the thirteen hypotheses had significant associations including six direct paths and three indirect effects in the model. The findings indicated the need for industry-university partnership in three main constructs including cooperation in education, the mobility of people and intellectual enhancement. Moreover, internship programme was the important linkage in achieving the overall university-industry partnerships goals, followed by the staff training programme, academic development, consultancy work, student learning activity and publication activity. In summary, the study demonstrates that teaching and learning relevance could be enhanced through optimizing industry’s enrichment activities into the learning process, improving the measures for accreditation in narrowing the gap between theory and practice and proactively improving the quality of teaching by exploring the staff training programmes.

Halloysite nanotubes (HNTs) offer excellent improvements in wide range of physical and engineering properties at low filler content. Due to their outstanding properties such as large aspect ratio, high surface area, flame retardant and good optical clarity, HNTs polymer nanocomposites are widely used in automotive, coating, packaging and medical devices. The results showed that the incorporation of halloysite nanotubes (HNTs) into polyester significantly improved dynamic mechanical properties of the nanocomposites including the glass transition temperature (Tg), storage moduli, microhardness, tensile properties, flexural properties and impact toughness. The mechanical properties of polyester-based nanocomposites were degraded after water-methanol exposure. The maximum microhardness, tensile, flexural and impact toughness values were measured at 1 wt% of HNTs reinforcement and the results also showed that HNTs improved the liquid barrier properties of polymers due to an increase in the tortuosity path. Several deterioration effects are likely to take place concurrently after seawater exposure. Plasticization reduced the mechanical properties of the nanocomposites and microorganisms such as microbes entered through microvoids to further increase the deterioration in mechanical properties of the nanocomposites. Microbes can cause chemical degradation and the breakage of hydrocarbons using seawater molecules. Nanocomposite biodegradation is highly undesirable for material integrity as these are mostly used in structural designs of marine applications. Structural damage may result in premature weakening which is often translated into system failure and enormous economic losses. The influence of short-term water absorption on the mechanical properties of HNTs-multi layer graphene-reinforced polyester hybrid nanocomposites was also investigated. After short-term water exposure, the maximum microhardness, tensile, flexural and impact toughness values were observed in case of polyester-multi-layer graphene (MLG) nanocomposites. It was also found that synergistic effects were not effective at a concentration of 0.1 wt % in producing considerable improvement in the mechanical properties of the hybrid nanocomposites.

The influence of Multi-Layer Graphene (MLG) and nanoclay on the performance of epoxy based nanocomposites has been studied. First, the theoretical aspects of nano-fillers and their impact on mechanical, thermal, and electrical properties of nanocomposites have been discussed. Then, nanocomposites were produced with varying weight fraction of nano-fillers (0.05, 0.1, 0.3, 0.5, and 1.0 wt%). It was observed that organic solvent, if not completely removed, causes porosity which acts as stress raiser and deteriorates the mechanical properties. The influence of reinforcement morphology on the mechanical properties of epoxy nanocomposites was studied using two nano-fillers: MLG and nanostructured graphite (NSG). It was observed that mechanical properties of nanocomposites were higher when the filler had corrugated and fluted topography. Modeling and simulation of epoxy nanocomposites were carried out using finite element method. It was observed that graphene based nano-fillers are efficient in scattering and dissipation of heat flux thereby increasing the thermal stability of epoxy nanocomposites. The macro-topography of bulk samples of monolithic epoxy and nanocomposites was modified by treating the samples with the abrasive papers. It was observed that surface notches, when exceed certain depth, cause degradation in mechanical properties. It was further observed that tensile properties are more sensitive to topography than flexural properties.

Epoxy is one of the most adaptable and widely sold high performance material in the world because of its excellent mechanical properties, thermal stability, chemical and corrosion resistance, low shrinkage, low cost, and ease of processing, etc. Graphene shows good potential for the fabrication of high performance polymer nanocomposites because of its unique planar structure and its superlative mechanical properties, thermal conductivity and excellent electrical conductivity. The layered structure allows a large surface contact area with the matrix and thus leads to improvements in the properties. This work aims at exploiting the potential use of graphene as a filler to reinforce epoxy matrix and the preparation of homogeneously dispersed epoxy/graphene nanocomposites. To explore the maximum property enhancement of graphene in epoxy, dispersion is the key factor. However, in the preparation of epoxy/graphene nanocomposites, there still exist some challenges. One of the largest obstacles it that graphene tends to reagglomerate in liquid epoxy, which is due to the strong van der Waals force on the graphene surface. If not properly dispersed, the agglomerated graphene will act as a defect within the matrix and consequently lower the properties of the nanocomposites. Therefore, the dispersion of graphene and the processing techniques should be studied. In this work, epoxy/graphene nanocomposites had been made by different processing techniques. Different characterization methods had been applied to evaluate the reinforcement effect. By end of this work, graphene dispersion techniques and sample preparation methods have been optimized. Epoxy/graphene nanocomposites have been prepared with enhanced properties.

Global climate change is one of the greatest challenges of the 21st century. Rising ambient temperatures and deterioration of weather patterns are anticipated to result from increased atmospheric concentrations of greenhouse gases caused in part by the use of fossil fuels for electricity generation and domestic heating purposes. The possibility of a global temperature rise of between 1 degree C and 4.5 degree Celsius has led to considerable research efforts into the effects of changes in temperature and other climatic variables. The increasing use of private capital in the energy industry has altered the focus from the provision of a service to the need to make profits from the production and sale of a commodity. Additionally, with respect to Luxembourg, the dependency on imported energy is an important risk factor. This thesis presents biomass as an essential alternative to substitute for some of the fossil fuels in the domain of heat, cooling and power generation. The results presented show an increase in energy utilisation and thus energy efficiency and reduction in emissions when used in combined generation modes as opposed to single generation. These results are gathered through meticulous analytical models, computational fluid dynamics (CFD), and laboratory testing of real life biomass systems. The technologies and analysis investigated here are targeted at those involved in climate change research, providing them with valuable data on the energy analysis of biomass and its associated emissions, highlighting the potential for reduction in pollutions when biomass is used instead of fossil fuels; in energy policy making; investors; engineers; and all others involved in the biomass design and operation of combined generation of biomass applications.

For many applications, including power generation, aerospace and the automobile industry, high temperature wear provides serious difficulties where two or more surfaces are able to move relative to one another. It is increasingly the case that with for example, aerospace applications, demands for ever more powerful and efficient engines that thus operate at higher temperatures, conventional lubrication is no longer sufficient to prevent direct contact between metallic surfaces and consequent accelerated wear. One phenomenon that has been observed to reduce metallic contact and thus high temperature wear and friction is the formation of what are termed ‘glazes’, essentially layers of compacted oxide wear debris that becomes sintered together to form a low friction wear resistant oxide surface. This thesis studies the nature of the wear encountered with four different combinations of Superalloys, slid together using a ‘block-on-cylinder’ configuration developed for accelerated simulation testing of car engine ‘valve-on-valve-seat’ wear. Predominantly, Nimonic 80A and Incoloy MA956 were used as sample materials and Stellite 6 and Incoloy 800HT were used as counterface materials.

Theoretical and Experimental results of research on the Direct Torque Control (DTC) of the Brushless Doubly Fed Reluctance Machine (BDFRM) are presented in this thesis. The main motivation for this work has been found in the relative simplicity of the DTC strategy and attractive properties of the BDFRM drive, foremost its cost-effectiveness associated with the use of a partially rated power electronics, and reliability of brushless structure of the machine itself. It is hoped that the project outcomes will be extremely helpful to the further study of the machine in light of its application in wind power generation and/or large pump systems. The thesis is essentially divided into three main parts. The first part is the theory development, which involves the analysis of the fundamental principles of DTC and BDFRM operation. The second part presents the comprehensive simulation studies of the developed control scheme for the machine in both sensor and sensorless modes. The computer studies have been performed to examine the performance of the controller based on a linear (ideal) machine model. The parameters used for this model have been obtained by off-line testing of a small Axially Laminated BDFRM prototype at Northumbria University, UK. The third part of the thesis contains a comprehensive set of experimental results that have successfully verified the control algorithm for the machine. Based on the Simulink® program, a Digital Signal Processor (DSP) control board from dSPACE® has been used to control a conventional IGBT inverter bridge.

This PhD research by project is for designers investigating relations between culture and design through an experiential perspective of Chi- nese culture in terms of developing a new understanding of ‘Chineseness’. ‘Chineseness’ in my work, can be re-mapped as a form of communication that deals with Chinese culture in design. It is not just along with historical stereotypes, nor a remote copy of other countries’ successful cultural trans- fers, but rather should be inseparable from the radical social phenomena and design culture already emerging within contemporary China. Through a series of design projects, my research is ultimately allowing Chineseness to be less implied and instead, to be made manifest, in terms of what behav- iours over symbolism and decoration. New knowledge is articulated through exploring my understanding and its shifts during my approach to re-map Chinese cultural elements in design and search for the meaning of ‘Chineseness’. This research remarks the stereotypes, generalisations and categorisations when designers deal with cross-cultural design from both non-Chinese and Chinese angles. The thesis comprises three parts. The first part is a contextual review of cultural elements and appropriate methods. The second part explores a systematic approach to reflecting Chineseness from various cultural an- gles. These action-research method-led projects describe three ways of ex- ploring the transfer of Chinese culture into design: symbolic, behavioural and political/philosophical. They culminate in an enabling developmental structure through which designers can deal with Chinese cultural com- plexity in design. The third part sees two final projects that reflect back and re-evaluate what Chineseness could be. The thesis contributes a three-layer structure that reflects Chinese cultural elements into design through meth- ods and analysis of values in practice. Additionally, for the readers sympa- thetic with a systematic design approach or cultural identitarianism, this work addresses a view of critical understanding for facing Chinese culture in design.