Catalytic carbon deposition reactions, using methane, ethane or synthetic natural gas (1.8 vol. % propane, 6.7 vol. % ethane and balance methane) as the carbon-containing gas feedstock with or without the addition of hydrogen, have been investigated over nickel, cobalt and iron catalysts supported on 3-dimensional carbon fibre supports, using both a horizontal tube furnace and an isothermal, isobaric induction furnace. The transition metal catalysts were prepared by impregnating 3-dimensional carbon fibre supports with a methanolic solution of the metal nitrate, using a wet impregnation technique, and the effects of temperature, gas composition and deposition time on their catalytic behaviour was studied. Samples were characterised using a number of complementary techniques, including X-ray diffraction, scanning electron microscopy, polarised light microscopy, transmission electron microscopy, thermogravimetric analysis, digital photography and weight change measurements. The findings from these techniques were used to explain the observed type and amount of carbon deposited. Nickel was found to be the most active catalyst and methane was found to be a poor carbon precursor for the catalytic deposition of carbon, from these findings nickel was chosen as the catalyst and ethane and synthetic natural gas were used as the carbon precursors, with and without the addition of hydrogen. The activity of the nickel catalyst was found to be dependant on a number of factors; weight percent used, temperature, gas feedstock used and deposition time. It was found, in all cases, that increasing the deposition temperature resulted in higher deposition rates, ethane was found to yield higher deposition rates than synthetic natural gas and the effect of hydrogen addition had a negligible effect upon the rate of carbon deposition for the reactions carried out in ethane whereas it was significant for the reactions carried out in synthetic natural gas. The majority of the carbon deposition took place in the first three hours of deposition, with extended deposition times only yielding small increases in the overall rate of carbon deposition. The type of carbon deposited varied from filamentous carbon i.e. carbon nanotubes, nanofibres and microcoils, to encapsulation. The factors affecting the type of carbon deposited were, the temperature of carbon deposition, with higher temperatures (800C) yielding encapsulation and lower temperatures (650C) yielding filamentous carbon, and the addition of hydrogen, with higher hydrogen concentrations favouring the formation of filamentous carbon over encapsulation. It was also found that the addition of hydrogen did not extend the lifetime of the catalysts. It was found that nickel catalysts could be used within larger carbon fibre preforms to catalytically deposit carbon at lower temperatures than those used in industry for the manufacture of carbon-carbon composites (> 1000C).

In this thesis a new instrument, the all-optical scanning acoustic microscope (O-SAM) is presented, it is a non contact scanning acoustic microscope (SAM) which uses lasers to both generate and detect surface acoustics waves (SAWs) The non contact nature of the O-SAM overcomes some difficulties associated with conventional SAMs because of the couplant and surface contact involved. This O-SAM also overcomes many of the problems associated with conventional laser ultrasound systems including those of sample damage and ablation, low signal to noise ratio and slow data acquisition. Furthermore, the instrument is adaptive enabling it to compensate to acoustic aberrations that can occur as a result of material microstructure. We believe this is a most significant feature that will greatly enhance its range of applications. This thesis examines some of the key technological developments required to develop the O-SAM, including the use of tailored optical generation pattern realised through the use of a spatial light modulator (SLM) and the development of a novel high speed analogue data acquisition system. This thesis presents the design and construction of the instrument and demonstrates its imaging capability on engineering materials using SAWs at 82 and 164MHz although the instrument is potentially capable of imaging at much higher frequencies. Images are presented on ceramic, steel and aluminium samples which demonstrate a range of contrast mechanisms and measurement techniques, including the interaction of the material with Rayleigh waves and Lamb modes for the purpose of defect detection and characterisation, and measurement of local variations in residual surface stress, changes in coating thickness, and plate thickness.

Relevant research has identified that high level of building emergency casualty (e.g. due to fire) has direct link with the delayed evacuation especially in residential and high-rising buildings. The traditional fire drill can only passively identify some bottleneck for evacuation after the building has been constructed and under its operation stage; and end-users normally lack of means to be effectively involved in the decision making process in the first place (e.g. building emergency planning and design) and lack of cost-effective and convenient means to be well trained about emergency evacuation at later operation stage. Modern building emergency management research has highlighted the need for the effective utilization of dynamically updated building emergency information. Building Information Modelling (BIM) has become the information backbone which can enable integration and collaboration throughout the entire building life cycle. BIM can play a significant role in building emergency management due to its comprehensive and standardized data format and integrated life cycle process. This PhD research aims at developing an end user oriented BIM enabled virtual environment to address several key issues for building emergency evacuation and planning. The focus lies on how to utilize BIM as a comprehensive building information provider to work with virtual reality technology to build an adaptable immersive serious game for complex buildings to provide general end users emergency evacuation training/guides. The contribution lies on the seamless integration between BIM and a serious game based Virtual Reality (VR) environment, which enables effective engagement of end-uses. By doing so potential bottlenecks for existing and new buildings for emergency evacuation can be identified and rectified in a timely and cost-effective manner. The system has been tested for its robustness and functionality against the research hypothesis and research questions, and the results show promising potential to support more effective fire emergency evacuation and planning solutions.

This thesis investigates the effectiveness of a passive treatment technology for Fe removal from low pH metal mine water. In addition, the use of electrocoagulation (EC) in removing Zn from circumneutral mine water and acid mine drainage AMD) was studied. Using an advanced oxidation process (AOP) followed by EC converted Fe(II) from coal mine drainage to a stable magnetic form of Fe. Research also studied the use of Cu electrodes in removing high concentrations of metals and sulphate from AMD. A 1 m³ field pilot scale vertical flow reactor (VFR) for passively treating an average flow of 0.6 L/min was deployed for 414 days. The system was gravity fed and removed an average of 65% of the Fe from pH 3 AMD. Potential removal mechanisms are a combination of bacterially mediated Fe(II) oxidation by Ferrovum myxofaciens and filtration of Fe nanoparticles. The build-up of the ochre bed did not compromise the permeability of the VFR. Mineralogical and microbiological studies combined with PHREEQC modelling show that the main mineral precipitated in the VFR is schwertmannite. Using EC, it was shown that the addition of Fe from neutral mine water by electrical dissolution of an Fe electrode resulted in Zn to be removed at a near neutral pH through a combination of co-precipitation and adsorption reactions. An inert Pt electrode rapidly removed 70 mg/L of Fe(II) from coal mine water by AOP applying 5 A during 4 min treatment. A second stage treatment adding Fe by electrical dissolution of Fe electrodes generated the required Fe(II):Fe(III) ratio and Eh-pH conditions to form magnetic Fe (magnetite). Further investigations into EC proved that the removal of sulphate and metals from AMD was highly effective when adding Cu from a copper electrode at 40 min at 5 A with aeration. Sulphate was reduced from 1324 mg/L to 112 mg/L without leaving Cu in solution. ESEM images and mineralogical studies of the precipitates showed that the mineral cuprite is formed. This has future potential implications for metal recycling/recovery from AMD.

The research conducted in this thesis aims to develop an efficient microwave delivery system employing miniature resonant microwave cavities, targeted at compact, flexible and ideally field-deployable microwave-assisted diagnostic healthcare applications. The system comprises a power amplifier as a solid-state microwave source and a load - as a single mode cavity resonator to hold the sample. The compactness of the practical microwave delivery system relies on the direct integration of the sample-holding cavity resonator to the power amplifier and inclusion of the built-in directional coupler for power measurements. The solid state power transistors used in this research (10W-LDMOS, 10W-GaN) were provided by the sponsoring company NXP Inc. In practical microwave delivery applications, the impedance environment of the cavity resonators change significantly, and this thesis shows how this can be systematically utilized to present the optimal loading conditions to the transistor by simply designing the series delay lines. This load transfer technique, which critically can be achieved without employing bulky, lossy and physically larger output matching networks, allows high performance of the power amplifier to be achieved through waveform engineering at the intrinsic plane of the transistor. Starting with the impedance observation of a rectangular cavity, using only series delay lines allowed the practical demonstration of the high power and high efficiency fully integrated inverse class-F (F-1) power amplifier. Temperature is an important factor in a microwave heating and delivery system as it changes the impedance environment of the cavity resonator. This natural change in both cavity and sample temperature can be accommodated through simplified series matching lines and the microwave heating system capable of working over substantial bandwidth was again practically demonstrated. The inclusion of the coupler maintained the compactness of the system. In the practical situations envisaged, the microwave delivery system needs to accommodate natural variation between sample volumes and consistencies for heating. The experimental work considered the heating of different sample volumes ii of water, and characterizing the change in the natural impedance environment of the cavity as a result. It was shown how the natural impedance variation can not only be accommodated, but also exploited, allowing ‘continuous’, high-efficiency performance to be achieved while processing a wide range of sample volumes. Specifically, using only transistor package parasitic, the impedance of the cavity itself together with a single series microstrip transmission line allows a continuous class-F-1 mode loading condition to be identified. Through different experiments, the microwave delivery systems with high-performance are demonstrated which are compact, flexible and efficient over operational bandwidth of the cavity resonators.

The aim of this study is to understand the complexity and control challenges of the locomotion of a three-link mechanism of a robot system. In order to do this a three-link robot gymnast (Robogymnast) has been built in Cardiff University. The Robogymnast is composed of three links (one arm, one torso, one leg) and is powered by two geared DC motors. Currently the robot has three potentiometers to measure the relative angles between adjacent links and only one tachometer to measure the relative angular position of the first link. A mathematical model for the robot is derived using Lagrange equations. Since the model is inherently nonlinear and multivariate, it presents more challenges when modelling the Robogymnast and dealing with control motion problems. The proposed approach for dealing with the design of the control system is based on a discrete-time linear model around the upright position of the Robogymnast. To study the swinging motion of the Robogymnast, a new technique is proposed to manipulate the frequency and the amplitude of the sinusoidal signals as a means of controlling the motors. Due to the many combinations of the frequency and amplitude, an optimisation method is required to find the optimal set. The Bees Algorithm (BA), a novel swarm-based optimisation technique, is used to enhance the performance of the swinging motion through optimisation of the manipulated parameters of the control actions. The time taken to reach the upright position at its best is 128 seconds. Two different control methods are adopted to study the balancing/stablising of the Robogymnast in both the downward and upright configurations. The first is the optimal control algorithm using the Linear Quadratic Regulator (LQR) technique with integrators to help achieve and maintain the set of reference trajectories. The second is a combination of Local Control (LC) and LQR. Each controller is implemented via reduced order state observer to estimate the unmeasured states in terms of their relative angular velocities. From the identified data in the relative angular positions of the upright balancing control, it is reported that the maximum amplitude of the deviation in the relative angles on average are approximately 7.5° for the first link and 18° for the second link. It is noted that the third link deviated approximately by 2.5° using only the LQR controller, and no significant deviation when using the LQR with LC. To explore the combination between swinging and balancing motions, a switching mechanism between swinging and balancing algorithm is proposed. This is achieved by dividing the controller into three stages. The first stage is the swinging control, the next stage is the transition control which is accomplished using the Independent Joint Control (IJC) technique and finally balancing control is achieved by the LQR. The duration time of the transition controller to track the reference trajectory of the Robogymnast at its best is found to be within 0.4 seconds. An external disturbance is applied to each link of the Robogymnast separately in order to study the controller's ability to overcome the disturbance and to study the controller response. The simulation of the Robogymnast and experimental realization of the controllers are implemented using MATLAB® software and the C++ program environment respectively.

Vibration serviceability is a governing factor in the design of low-frequency structures, which are sensitive to human-induced loads. To achieve reliable vibration estimates, structural engineers need to model the combined pedestrianstructure system as close to reality as possible. The most uncertain aspect in the modelling is accounting for pedestrian interaction with perceptibly vibrating structure. To improve understanding of this aspect, the thesis aims to provide experimental and numerical modelling of walking locomotion on lively structures in the vertical direction. Experimental programmes were conducted to provide characteristics of walking gait on both rigid and lively surfaces, where the former was used as benchmark for comparison. Both kinematic and kinetic parameters were measured using a motion capture system. Discrepancies of the gait parameters between data collected on imperceptibly and perceptibly vibrating surfaces, as consequences of the pedestrian-structure dynamic interaction, were quantified. The unique database provided in this thesis contributes to the understanding of locomotion on the vibrating surface and, therefore, can be used for calibration of pedestrian models intended for civil engineering applications. An interactive model was developed, using a biomechanical model to represent the pedestrian. The novel feature of this model is to account for two-way interaction between the pedestrian and the structure. A sensitivity analysis and validations of the proposed model against experimental data were also provided. Results of the modelling work inform designers detailed evaluations of performance of the model on both virtual and as-built structures.

Virtual testing using high strain rate material data can play a major role in realising an optimum design of composite parts for impact and crash resistance. The objective of this thesis was to develop methodologies for generation of high strain rate properties of composite material constituents and demonstrate their use with an already developed multi-scale modelling platform [1] for prediction of the probabilistic strength of composite materials. Two different approaches were used for generation of the high strain rate data of the fibres and resins. The first one is the direct evaluation of properties through experimental testing and the other is an inverse modelling approach which uses the test data of composites to provide information on the constituent data, using the micro-scale models [1], through an iterative optimisation study. A split Hopkinson tensile bar was developed with an innovative clamping methodology which was used to generate the high strain rate tensile characteristics of carbon fibres. An inverse modelling methodology was used in conjunction with the high strain rate data from the longitudinal and transverse compression of unidirectional composites to generate the longitudinal and transverse compressive properties of the fibre. The constituent’s data generated was then further used in the multi-scale model for probabilistic prediction of respective composite strength through Monte Carlo simulations. This study was primarily focussed on generating data for carbon fibre composites. The contribution to knowledge from this study is the demonstration of the use of hybrid approach of generation of data in conjunction with multi-scale models for prediction of the strength properties of composites. This approach can be further applied for different multi-scale models relating to different composite architecture for evolution of new optimum designs for impact and crashworthy applications. Specific areas of novelty related to this thesis can be summarised as follows: 1) Development of an innovative clamping methodology for high strain rate tensile testing of fibres. 2) Development of an inverse modelling approach for generation of longitudinal and transverse compressive properties of fibres. 3) Use of analytical Jacobian for improved efficiency during optimisation for inverse modelling studies 4) Generation of high strain rate data of standard carbon fibres such as T800, T700 and IM7.

The popular use of concrete, particularly in the construction industry, has continually challenged researchers to advance its performance to new levels. Research in this area has led to substantial ideas of reactive powder concrete (RPC) which is developed by controlling three main variables: composition, pressure during setting period, and post-set heat curing. A growing community of research has emerged to define the physical and mechanical properties of RPC, but to date few have focussed on the high temperature behaviour and aging effects after exposure to fireand that influence the durability of concrete. This research aimed to characterise the thermo-physical properties of RPC and to quantify the microstructural transformation caused by (i) high temperature curing, and (ii) fixed and cyclic high temperature exposure (at 28-day strength). The experimental work mainly used a RPC mixture and involved three defined stages. Firstly, the optimisation of RPC was investigated by analysing the mix composition and measuring the corresponding mechanical properties of RPC with variables such as heating rate, heating duration, and starting time of heating. Secondly, the transformation of microstructural properties was investigated with respect to the pre- and post-treatment conditions and included pore network evolution, elemental composition, and image analysis of the interfacial transition zone (ITZ). Thirdly, the response to high temperature exposure was analysed by focussing on the residual compressive strength and alteration of microstructural properties (after both static and cyclic temperature exposure of varying levels). The main findings are summarised as follows: (1) heat curing appears to have optimum impact (after casting) at a ramp rate of 50 °C/hr for 48 hours; (2) heat curing treatment induced some effects such as pore filling by tobermorite and xonotlite, with some dehydroxilation of C-S-H gel and Ca (OH)2; (3) the thermo-physical properties of RPC were all reduced following heat treatment/ exposure due to crack network progression; (4) after elevated temperature exposure, the compressive strength of RPC decreases due to differential shrinkage between the matrix and aggregate phases.

The principal aim of this work was to investigate and develop modelling techniques capable of accurately and robustly analysing expansion anchor bolts in concrete under tensile loading. Of special interest was the influence of low edge distances on such devices. Since the 20th century increased demands for flexibility, safety and cost have lead to significant development of new anchor products. Modern design methods for new products follow a scientific approach but still rely on substantial and expensive programs of experimental testing. Current design methods for structural designers using anchors are based on semi-empirical approaches derived from extensive experimental testing. It is proposed that much of this experimental work can be replaced with numerical modelling. A number of suitable finite element constitutive models are considered. Initially a Multisurface Plasticity Model and a Traditional Crack Model using a Multiple Fixed Crack (MFC) formulation are considered. Both are shown to give satisfactory results when used to analyse a common, plane-stress benchmark problem. However, although the Plasticity Model gave a better post peak response a 3D implementation was not available within the chosen FE framework. Spurious stress accumulation was identified as the cause of the problems with the MFC Model and its various causes are investigated in detail. A Total Strain Based Rotating Crack Model was chosen as an alternative constitutive model and together with suitable modelling parameters was able to reduce these spurious stress accumulation effects to an acceptable level. 3D modelling of a non-expanding, fully bonded anchor at various distances to the free edge accurately predicted the expected reduction in strength and compared well with reduction factors supplied by anchor manufacturers. The study was extended to include the effect of two free edges and results allowed the strength reduction to be calculated for any arbitrary position rather than for just the single edge approach given in the anchor design guides. Modelling of anchor expansion was tackled on two fronts. Firstly anchor-concrete interfacial behaviour was considered. A Coulomb Friction Model applied to zero thickness structural interface elements to simulate the pressure dependant frictional bond. The role of FE model geometry and material properties in producing a realistic interfacial stress profile was studied in detail. For the kinematics of the expansion modelling of the expander mechanism as a contact problem was found to be the most accurate approach. However, limitations of the modelling framework required that the contact analysis be performed separately and resulting contact stress profile be applied to the existing, noncontact problem. This approach, although somewhat inflexible, provided a useful insight into the important factors pertaining to both the geometric and constitutive models. Results showed realistic crack patterns and demonstrated the effect of varying expansion pressures on the structural response of the anchor bolt. The modelling approach used in this study was highly complex in terms of the multiple non-linear material models and the associated solution process. This resulted in problems with robustness and stability. As an alternative and inherently stable modelling framework a Sequentially Linear (SL) Model was developed. In its isotropic form it proved fast, accurate and reliable for plane-stress anchor problems. Orthotropic fracturing and 3D analysis capabilities were introduced to the model and a number of rules for crack initiation and orientation were tested. Although limitations in the possible crack orientations produced significant mesh bias to the crack pattern, the model was able to capture the changes in anchor behaviour associated with reduced edge distance. The overall assessment is that that SL Model has great potential especially for highly nonlinear problems where stability and robustness are issues.