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This thesis reports a toughening concept for carbon fibre reinforced polymer composites using continuous thermoplastic nanocomposite fibres in which dissolvable phenoxy was used as a toughener for the epoxy matrix and at the same time as a carrier to deliver graphite nanoplatelets (GNP) into desired positions of composites. Nanocomposites containing different GNP contents were prepared via masterbatch dilution method, and these were melt spun and drawn into fibres at varying take-up speeds. Structural characterisation revealed that the dispersion of GNP worsened with both increasing GNP content and take-up speed, especially in the fibre core region. Moreover, due to the strong shear stress exerted by the spinneret wall, GNP in the outer layer of the fibre showed a tangential orientation, which was absent in the fibre centre. As a consequence, the Young's modulus, which is a low-strain property, increased with both GNP content and take-up speed, while the tensile strength remained relatively unchanged because it was more sensitive to the GNP agglomeration. Theoretical analysis with simple rule of mixtures and shear-lag theory suggested the enhanced Young's modulus originated from the increased orientation degree (η₀) of GNP at high take-up speeds, which was not attainable from SEM/TEM characterisation. Moreover, the η₀ was found to be in good agreement with the normalised areal ratio (ratio of the area of the imaginary fibre sheath layer to the whole cross-sectional area) of fibres at each take-up speed, which could indicate the variation in the reinforcing efficiency of GNP in the fibre core and sheath layer due to the different dispersion qualities of GNP in these two regions. The electrical percolation threshold was 8.0 wt% for compression moulded plates, which was relatively lower than the rheological one (8.8 wt%) due to the fact that less GNP was required to form a conductive network that can be detected by the static electrical measurements. Conversely, fibres with the same GNP content were not conductive because of the orientation, separation and aggregation of GNP upon drawing. The dissolution behaviour of pure phenoxy and GNP/phenoxy fibres was studied in model systems using optical microscopy. Results showed that GNP/phenoxy nanocomposite fibres took longer than pure phenoxy fibres to completely dissolve, probably because the tangentially oriented GNP in the outer layer of the fibre hindered the interdiffusion of phenoxy chains and RTM6-2 precursors. The dissolution study also suggested that too high a dissolution temperature could lead to a premature gelation of the epoxy resin and that thinner fibres were preferred for use in composites. As a proof of concept, GNP/phenoxy fibres were 3D braided with carbon fibre (CF) to produce hybrid strands, followed by resin infusion to prepare composite laminates. Both phenoxy and GNP improved the Mode I interlaminar fracture toughness (GIc) of composites although phenoxy exhibited a more pronounced toughening effect. This was attributed mainly to the significantly intensified CF breakage and pullout in regions where pure phenoxy or GNP/phenoxy fibres initially located, as evidenced by the SEM observation on the fracture surfaces of composites. Crack deflection induced by the phase-inverted RTM6-2 nodules in the presence of relatively high local concentration of phenoxy, crack pinning caused by GNP and GNP pullout/separation were also proposed as the toughening mechanisms.

Typical cardiovascular diseases are mostly asymptomatic until fatal consequences are caused. Patient-specific simulations have the potential to guide clinical diagnosis but are impeded by the missing patient-specific material properties. To close this gap, this dissertation explored the role of the two most significant loading components, collagen and elastin, in defining mechanical responses of artery walls. These associations are crucial for understanding the mechanical remodelling of diseased tissues and the potential failure mechanisms implicated. These aims are achieved through experiments and numerical approaches. Firstly, collagen and elastin fibre parameters of human aortic dissection flaps were extracted from histology slides. Their material properties and relationships with fibrous parameters were also studied. Secondly, a computational framework based on the unsupervised deep learning UNet model was proposed to characterise the heterogeneity of vessels. Lastly, a simulation framework was developed and used for parameter studies to estimate artery material performances according to a few critical collagen fibre parameters. The results demonstrated that fibre dispersion and waviness in the aortic dissection flap changed with patient age and clinical presentations, and these changes can be captured by the material constants in the strain energy density function. Additionally, high material heterogeneity was characterised by the localised strain maps and simulations. Strain maps of axial strips demonstrated a zebra pattern with vertical high strain concentrations due to fibre configurations when subjected to uniaxial tensile tests. Furthermore, based on the fibrous parameters obtained in the preceding study, the proposed simulation method predicted strain-stress curves that fit well with experiments. Parameter studies using this methodology proved that the fibre recruitment efficiency dictates tissue mechanical performances and largely depends on the primary fibre orientation regarding the loading direction. In addition, collagen fibre waviness determines the starting point of nonlinearity in the strain-stress responses of arteries. In summary, the remodelling of collagen and elastin fibres within artery walls can explain the clinical observations and is mechanically significant in predicting the adjustments of material performances.

Textile-based wearable electronics, as the next generation of wearable devices, have attracted considerable interest. Conductive fibres are the building blocks for developing these flexible and wearable devices. Electroless deposition (ELD) is a traditional method to deposit metal nanoparticles on different materials by autocatalytic chemical reduction of metal cations in a liquid bath. However, there are no catalytic sites on the fibre surface to initiate the ELD. To solve this problem, this research aims to coat polyphenols including dopamine, tannic acid and curcumin on the fibre surface via pi-pi stacking and then served as the platform to capture catalysts via cation-pi interaction for depositing metal nanoparticles on fibres. By introducing the polyphenols-assisted ELD, conductive yarns and fabrics were obtained and the resistance of Ni-coated cotton yarns reached 0. 05 ohm/cm. The fibre interface molecular engineering provided strong adhesion forces between the metal layer and the fibre surface, resulting in durable metal-coated yarns and fabrics. On the other hand, the surface morphology of metal deposits on fibres was controlled in nanoscale by adjusting the ELD time to yield the metal coatings with multilayers shape on fibre surface in which unfilled gaps between metal nanoparticles prevented the metal films from cracking under bending. In addition, the Kelvin structure model was proposed to illustrate the relationship between the conductivity and flexibility of metal-plated fabrics. As a result, the normalised resistance of Ni-deposited fabrics (20 min ELD) was only 1.6 after 1000 mechanical bending cycles (bending radius = 0.1 mm). To construct these metallised substrates into wearable sensors, the fibrous structure was utilised. Based on the change of fibre-to-fibre contacts in metal-coated yarns and 3D fibrous sponges under mechanical deformations, fibre-shaped wearable electronics including finger bending sensors, arm bending sensors, pressure sensors, touch sensors and human-machine interfaces for monitoring human motions were obtained by collecting different resistance values. The research indicated that polyphenols-assisted ELD can metallise other flexible substrates and extend the applications of conductive and flexible samples.

Human hair, like other Alpha-keratinous fibres, is a highly complex biomaterial. The application of analytical methods to human hair is used in the assessment of chemical damage, constituting the first step to prevent hair deterioration and to develop new products; making hair analysis a very important method for the cosmetic industry and hair researchers. Very little systematic research on the protein patterns of the keratin structures of human hair and how they relate to chemical damage have been reported. This study set out to develop advance techniques which are only rarely used on keratin fibres, where it focuses on gel electrophoresis. The study aims to standardise the data acquisition process, also refining the data analysis methodology for extracting more in-depth information at the molecular level. The techniques included two different types of electrophoresis (SDS-PAGE and the PhastSystem), differential scanning calorimetry (DSC), attenuated fourier transmission spectroscopy (ATR-FTIR) and transmission-FTIR. By suggesting the extraction, staining and destaining times allows to minimise the measurement variability in the protein patterns, thus allowing for more repeatable protein pattern analysis with less sample-to-sample variation. Methods for both the standardisation length of the protein patterns and using the normalisation of the intensity variations have been proposed and this approach has not been attempted before. In human hair the clustering method, demonstrates high correlation between populations of human hair samples. The content of the amino acids, cysteine and cysteic acid, show in the case of darker hair colour a systematic increase, confirmed by use of transmission-FTIR along with ATR-FTIR. A significant increase in extractability is accompanied with an increase in cysteic acid content in cuticle, as presented by dark shade sample with high extractability. For animal hair, the chemical damage in the keratin intermediate filament proteins (KIFs) or keratin intermediate filament-associated proteins (KAPs) levels was analysed and cluster analysis was proposed as a way to classify animal hair fibres by sub species. The application and optimisation of the electrophoresis analytical methods to human and animal hair in the assessment of chemical damage is novel and very useful for the cosmetic industry, hair researchers and related forensic applications. A further investigation using transmission FTIR could be used in the analysis of the amount of cysteic acid in the cortex could be carried out similar to that which was carried out for the cuticle.

Ongoing concerns about the adverse health effects of carbon particulates in diesel engine exhausts continue to drive the quest for improved performance from Diesel Particulate Filter (DPF) systems. Two of the main areas in which improvements are being sought are in enhanced filtration efficiency of very fine particles (< 50 nm), particularly immediately after regeneration (the periodic removal of accumulated particulate via combustion), and in improved thermal shock resistance. To contribute to these aims, this work focuses on creating novel composite materials through the introduction of fine ceramic fibres. Filtration efficiency is considered by experimental measurement of porosity and permeability. Porosity of the material is shown to increase with fibre content, providing a larger volume for soot collection. The permeability is shown to slightly decrease due to the fine nature of the fibres. However, these small fibre diameters, in comparison to the larger particles, offer an increased surface area and scope for an improved soot trapping capability. A simulation, modelling the particles and fibres as simplified spheres and cylinders, allows an understanding into the effect of porosity, fibre proportion, and the sizes of the particles and fibres on the permeability. An empirical equation linking these factors is suggested. A model of this type, on a hybrid particle-fibre-void composite material, has not been studied in the literature, and so offers a novel insight into the complex behaviour of such materials, practicable not only to DPFs, but to any other applications of such composites systems. The model is shown to have good agreement with the experimentally derived data. Finally, the effect of fibres on the thermal shock resistance is investigated. The fibres show improved fracture toughness, and variability in the stiffness which suggests, via a derived figure of merit, that thermal shock resistance improves with increased fibre proportion. Thermal shock is induced experimentally using a vacuum plasma sprayer, and the experimental results, measured as a decrease in stiffness as a consequence of micro-cracking, are comparable to those of the merit index. The study concludes that there appears to be a significant benefit to adding fine ceramic fibres into current DPF materials. The increased porosity, whilst also significantly increasing the specific surface area, suggests the filter could offer a higher soot loading capacity, thus lengthening the time between regenerations. The inclusion of small diameter fibres predicts that the period of initially low filtration efficiency of a clean filter could be shortened, with little impact on the permeability. Fibres also offer significant advantages for the thermal shock resistance. Fibres are well-known for their toughening ability and this remains true for these hybrid particle and fibre composites.

The experimental work programme developed in this study investigates the behaviour of novel concrete reinforcement for the wave energy converters. The reinforcement included fibre-reinforced polymer (FRP), synthetic fibres, steel fibres and ultra-high-molecular-weight polyethylene (UHMWPE). 24 cube specimens were tested using a pull-out test where no splitting was allowed to develop to examine the bond between FRP (glass and carbon) bars and concrete. 45 beam specimens were subjected to three-point or four-point bending tests where the beams were bent until their failure in order to study the structural behaviour of flexural concrete elements reinforced with internal FRPs, external FRPs as well as fibrous reinforcement. A large-scale WEC prototype was produced, and design of reinforcing this prototype with novel reinforcement was proposed. The bond behaviour between FRP bars and concrete as well as influence of seawater ions were investigated. The shear strength contribution of FRP-reinforced concrete beams was analysed. Also, the structural behaviour of beams reinforced or strengthened with FRPs was presented and compared with estimations using existing methods. A concept of Crack Resistance Indices (CRIs) was introduced to reflect the cracking behaviour of the beams. Appropriate methods for evaluating the flexural strength of beams externally bonded with CFRPs using epoxy resin was developed. Influence of the water and seawater exposures on the CFRP strengthening capacity was also discussed. Addition of macro-synthetic fibres to the concrete at a dosage of 20 kg/m3 significantly improved the toughness of FRP-strengthened beams. Longitudinally aligning macro-steel fibres into concrete beams could provide the latter with competitive flexural and shear strengths. The relation between the aligned fibre dosages and the beam's flexural strength was formulised. Influence on the flexural strength from factors of the concrete strength, addition of cementitious materials and the alignment effectiveness was also studied. A circular Vierendeel-truss-type WEC prototype was designed and produced from precast concrete elements. Assembly of the prototype was accomplished whilst reinforcing with UHMWPE ropes remained at the proposal stage. A 3D printed concrete beam reinforced with UHMWPE ropes was also trialled.

Bone transplantation is one of the most frequent procedures performed worldwide. Common grafts include autologous, allogeneic, xenograft or synthetic grafts. The availability of autologous grafts is limited, and leads to donor site morbidities, while allografts and xenografts are associated with the risk of disease transmission, immune rejection and have poorer osteointegration than autografts. BioglassÃ’ is a commonly used synthetic graft that upon implantation, bonds to hard tissues through hydroxyapatite layer formation however, it comes in block or particle form. Alternatively, fibrous scaffolds are easier to handle, and they resemble the fibrillar structure of bone extracellular matrix. Cotton-wool like bioactive glass fibres can be easily packed into the defect site, however, their effect on bone formation and angiogenesis has not been evaluated. In this thesis it is hypothesised that 70S30C cotton-wool like bioactive glass fibres have osteo-stimulatory properties and are able to enhance tube like network formation which ultimately could be exploited for non-load bearing bone regeneration applications. Cotton- wool like bioactive glass fibres, were created through the electrospinning process. Several electrospinning parameters were optimised to produce bead free fibres with homogeneous diameters. Human bone marrow mesenchymal stem cells (MSCs) were used to assess in vitro effect of the fibres on cell attachment and proliferation, however the data was inconclusive. The 7osteo-stimulatory effect of bioactive glass has been credited to the ion release, hence conditioned media was obtained from the dissolution of the fibres in cell culture medium and it was shown not to inhibit cell proliferation. Furthermore, it was revealed that the conditioned media combined with the commonly used osteogenic supplements resulted in earlier and stronger osteogenic differentiation of MSCs than commercially available osteogenic media alone. Furthermore, the osteo-stimulatory ability of fibre conditioned media surpassed that of BioglassÃ’. MSCs grown in the presence of fibre conditioned media produced higher levels of calcium, collagen and osteocalcin. Gene expression analysis revealed that MSCs undergo faster osteogenic differentiation in the presence of conditioned-osteogenic media than in osteogenic media alone. However, the fibre conditioned media failed to enhance tube-like network formation when human umbilical vein endothelial cells and MSCs were co-cultured in collagen gel. This thesis demonstrates, for the first time, ability of the 70S30C bioactive glass conditioned media to induce osteogenic differentiation of MSCs, which could have a broad range of applications, from bone fracture healing to osteoporosis treatments, osteosarcoma lesion healing and periodontal disease management.

Given a group word w in k variables, a group GM and g &in; G, we consider the set Sw(g) of k-tuples (g1,..., gk) &in; G(k) such that w(g1,..., gk) = g and when G is finite, the size of Sw(g), Nw(g). N. Amit conjectured that for any finite nilpotent group G and any word in k variables, Nw(1) ≥ |G|k-1. In this thesis we first prove Amit's conjecture for finite groups of nilpotency class 2. This was independently proved by Levy in [1]. More generally, we study the class functions Nw for this class of groups and show that the inequality can be improved to Nw(1) ≥ |G|k/|Gw (Gw is the set of w-values in G) if G has odd order. This last result is explained by the fact that the functions Nw are characters of G in this case. For groups of even order, all that can be said is that Nw is a generalized character, something that is false in general for groups of nilpotency class greater than 2. We characterize group theoretically when Nxn

It is crucial for a building to maintain structural stability when subjected to multiple and sequential extreme loads. Safety and economic considerations dictate that structures are built to resist extreme events, such as a earthquakes, impacts, blasts or fires, without collapse and to provide adequate time for evacuation of the occupants. However, during such events, some structural damage may be permissible. Design codes do not account for the scenario where two extreme events occur consecutively on a structure nor do they address the situation of the structure having some initial damage prior to being subjected to a fire load. This work begins by detailing the major inconsistancies between designing reinforced concrete structures for extreme mechanical loads and designing for fire. The material behaviour and traits of the constitutive parts (i.e. the concrete and the steel), including post yielding behaviour, thermal relationships and their interaction with each other are all explored in detail. Comprehensive experimental and numerical investigations are undertaken to determine whether, and to what extent, phenomena such as tensile cracking and loss of the concrete cover affect the local and global fire resistance of a member or structure. The thermal propagation through tensile cracks in reinforced concrete beams is examined experimentally. A comparison is made between the rate of thermal propagation through beams that are undamaged and beams that have significant tensile cracking. The results show that, although small differences occur, there is no significant change in the rate of thermal propagation through the specimens. Consequently, it is concluded that the effects of tensile cracking on the thermal propagation through concrete can be ignored in structural analyses. Significantly this means that analyses of heated concrete structures which are cracked can be carried out with heat-transfer and mechanical analyses being conducted sequentially, as is currently normal and fully-coupled thermo-mechanical analyses are not required. The loss of concrete cover and the impact on the thermal performance is examined numerically. A comparison is made of the thermal propagation, beam deflections and column rotations between structures that are undamaged and structures that have partial cover loss in a variety of locations and magnitudes. Results show that any loss of cover can lead to unsymmetrical heating, causing larger deflections in both vertical and horizontal directions, which can result in a more critical scenario. It is concluded that the effect of cover loss on the thermal performance of the structure is extremely significant. A new approach to numerically simulating the loss of cover by mechanical means from a member is developed. This new approach provides the user with an extremely flexible yet robust method for simulating this loss of cover. The application of this method is then carried out to show its effectiveness. A large experimental study carried out at the Indian Institute of Technology, Roorkee and separately numerically modelled at the University of Edinburgh. Unfortunately, due to unforseen circumstances, the experimental data available is limited at this time and as a result the validation of the numerical simulation is limited. Through these investigations it is clear that it is necessary to develop a method in enhance the stability and integrity of the concrete when subjected to the scenario of a fire following another mechanically extreme event. Therefore, finally a method is proposed and experimentally investigated into the use of fibres to increase the post crushing cohesiveness of the concrete when subjected to thermal loads. Results show that the fibrous members display an increased thermal resistance by retaining their concrete cover through an enhanced post crushing cohesion. From this investigation, it is concluded that the use of fibrous concrete is extremely beneficial for the application of enhancing the performance under extreme sequential mechanical and thermal loading.

Carbon nanotubes (CNT) are a new form of industrially relevant nano-scale particle and are seen as the cutting edge of the burgeoning nanotechnology revolution which promises to impact on all our lives. Due to high length to diameter ratio, CNT are perhaps the most well known of a growing collection of high aspect ratio nanoparticles (HARN). However the production and use of carbon nanotubes has presented an interesting toxicological question based on its structure and raised the question ‘are carbon nanotubes like asbestos?’. Few people are unaware of the devastating global pandemic of diseases caused by asbestos and similarities in needle-like shape between asbestos and nanotubes have raised fears that nanotubes may mimic asbestos-type disease. The purpose of this study was to investigate this link, based on the wealth of information known about the toxic effects of certain forms of fibre on the respiratory system. From this we hope to identify those carbon nanotubes which are hazardous whilst not prejudicing the use of those industrially relevant materials which can be used safely. Within fibre toxicology there exists a central paradigm which outlines the main properties a fibrous particle must possess if it is to exert pathogenic effects in the body. This paradigm outlines the importance of length, thinness and biopersistence to a fibre and an absence of one or more of these attributes results in a loss of pathogenicity. We took this paradigm and, using suitable asbestos and non-asbestos controls, applied it various morphological forms of carbon nanotubes using an in vivo model. The resultant data demonstrates for the first time that asbestos-like pathogenic behaviour associated with carbon nanotubes is closely linked to the morphology of the nanotubes and their aggregates. Specifically our results showed that CNT which possessed a long, straight length were highly inflammogenic and fibrogenic within the peritoneal cavity of mice; a model sensitive to the pathogenic effects of fibres. As well as length, the importance of biopersistence in the pathogenesis of fibrous particles has been known for many years and is a central attribute affecting the pathogenicity of fibres. Amphibole asbestos is known to be durable, a commercially exploited attribute and as such is biopersistent in the lung which is a key feature of its pathogenicity. Glass fibre on the other hand is bio-soluble, and whilst long and inhalable, does not cause significant disease due to its lack of biopersistence. Based on the grapheme structure of CNT which impart exceptional strength and rigidity and the chemical inertness of carbon we would hypothesis that CNT would be biopersistent and therefore fulfil another of the criteria of the fibre pathogenicity paradigm (FPP). Our aim therefore has been to establish the durability of CNT against fibrous particles of known durability using a synthetic solution maintained at a pH to simulate the lung environment. Using a range of 4 CNT and using both durable and non-durable fibres such as amphibole asbestos and glass fibre to bench mark our result; we demonstrated that 3 of the 4 CNT tested displayed exceptional durability whilst the fourth lost approximately 30% of its mass during the experiment with concomitant reduction in pathogenicity. As well as length and biopersistence, the surface of a particle has been shown to contribute to the overall toxicity of a particle and in certain circumstances, such as that of quartz, the surface of the particle can be the biologically active component. In the case of carbon nanotubes, surface functionalisation is commonly used for various endpoints including the addition of various tags and labels for tracking. As such our further aim was to investigate the relationship between the length-dependent pathogenicity of a fibre sample and the surface of the fibre. By using different forms of functional groups attached to the surface of a pathogenic carbon nanotube we aim to critically test if the level of inflammation and fibrosis triggered in vivo can be altered by simple alteration of the surface. Our results showed that surface modification of CNT could alter the inflammogenic and fibrogenic effects of CNT which may have important implications when considering the hazard assessment of functionalised HARN. As CNT are not the only form of fibrous nanomaterial and within this project we also attempted to determine the applicability of the FPP to further high aspect ratio nanomaterials. In order to do this we set out to determine the generality of this hypothesis by asking whether nickel nanowires, a radically different form of HARN to CNT, show length-dependent pathogenicity. Nickel oxide nanowires synthesised to be predominantly long (>20 μm) act similarly to amphibole asbestos in showing the ability to elicit strong inflammation in the mouse peritoneal model in a dose dependent manner; inflammation was not seen with the short (<5 μm) nanowires. In summation, the results from this study are the first to show that long HARN can indeed behave like asbestos when in contact with the sensitive mesothelium. This study suggests a potential link between inhalation exposure to long nanotubes and asbestos-related disease, especially mesothelioma and as such this may have immediate implications across many disciplines if care is to be taken to avoid a long term legacy of harm.

In this thesis, a bundle F →(M,ω) → B is said to be Lagrangian if (M,ω) is a 2n- dimensional symplectic manifold and the fibres are compact and connected Lagrangian submanifolds of (M,ω), i.e. ω |F = 0 for all F. This condition implies that the fibres and the base space are n-dimensional. Such bundles arise naturally in the study of a special class of dynamical systems in Hamiltonian mechanics, namely those called completely integrable Hamiltonian systems. A celebrated theorem due to Liouville [39], Mineur [46] and Arnol`d [2] provides a semi-global (i.e. in the neighbourhood of a fibre) symplectic classification of Lagrangian bundles, given by the existence of local action-angle coordinates. A proof of this theorem, due to Markus and Meyer [41] and Duistermaat [20], shows that the fibres and base space of a Lagrangian bundle are naturally integral affine manifolds, i.e. they admit atlases whose changes of coordinates can be extended to affine transformations of Rn which preserve the standard cocompact lattice Zn Rn. This thesis studies the problem of constructing Lagrangian bundles from the point of view of affinely at geometry. The first step to study this question is to construct topological universal Lagrangian bundles using the affine structure on the fibres. These bundles classify Lagrangian bundles topologically in the sense that every such bundle arises as the pullback of one universal bundle. However, not all bundles which are isomorphic to the pullback of a topological universal Lagrangian bundle are Lagrangian, as there exist further smooth and symplectic invariants. Even for bundles which admit local action-angle coordinates (these are classified up to isomorphism by topological universal Lagrangian bundles), there is a cohomological obstruction to the existence of an appropriate symplectic form on the total space, which has been studied by Dazord and Delzant in [18]. Such bundles are called almost Lagrangian. The second half of this thesis constructs the obstruction of Dazord and Delzant using the spectral sequence of a topological universal Lagrangian bundle. Moreover, this obstruction is shown to be related to a cohomological invariant associated to the integral affine geometry of the base space, called the radiance obstruction. In particular, it is shown that the integral a ne geometry of the base space of an almost Lagrangian bundle determines whether the bundle is, in fact, Lagrangian. New examples of (almost) Lagrangian bundles are provided to illustrate the theory developed.

This thesis investigates the constant pressure cake filtration of interacting cellulose fibre/TiO2 (rutile) mixtures, and involved experimental studies using an automated pressure filtration apparatus. The influence of suspension composition, filtration pressure and solution environment on filtration has been discussed in relation to cake properties such as average cake porosity and specific resistance. To help interpret the filtration results, sedimentation data were also obtained. The average porosities of filter cakes formed from pure rutile and fibre suspensions in deionised water were approximately 0.6 and 0.75, respectively, and a steady and progressive increase in porosity with fibre fraction was generally observed. With filtrations at 450 kPa, the average specific cake resistances for pure fibre and rutile in deionised water were approximately 9.4x1013 and 4.2x1012 m kg-1 respectively, with the variation of specific resistance with solids composition showing a minimum. Similar trends were observed at other tested filtration pressures with suspensions in deionised water but not with filtrations of suspensions in 0.2 M NaCl and 0.1 M CaCl2 solutions. The minima in average specific cake resistance with solids composition for feeds in deionised water was attributed to rutile-fibre interactions. Abrupt transitions in cake structure were evident part way through some filtrations, and resulted in unexpected filtrate flow behaviour. This is an interesting phenomenon, and not only were the changes in cake structure relatively reproducible, but also the nature of the change could be altered by changes in filtration pressure, solids composition and/or solution environment. The study of fibre/particle binary filtration behaviour, in particular the porosity and specific cake resistance trends, were substantiated by relevant theoretical treatment and modelling analysis. With the porosity trends, an additive porosity concept seemed to represent the data better than interparticle penetration models. With the specific cake resistance trends, a semi-empirical equation was proposed which appeared to represent a wide range of binary mixture filtration data. A mathematical framework was also developed in an attempt to understand the underlying physical mechanisms which led to filter cake restructuring, and possible explanations were postulated.

Ovarian cancer is one of the five most common causes of cancer death in women in the USA and UK. It is usually diagnosed when it is well established beyond the ovary in the peritoneum. Intravenous injection of cisplatin is a common palliative therapy for ovarian cancer patients. Intraperitoneal therapy has been shown to improve survival for patients. Poly(lactide-co-glycolide) (PLGA) is a biodegradable polyester which has been proven safe for medical implantation. PLGA microspheres or fibres have been considered in this work as depots for delivering intraperitoneal cisplatin directly to the tumour site. The aims of this work were (1) to develop microsphere depot formulations with improved drug release profiles compared to previous work; (2) Novel cisplatin containing solid and hollow fibres were to be developed and investigated as alternative structures for depot devices; (3) The drug release profiles were to be examined using mathematical models to allow rational comparison of the devices. It was found that cisplatin containing PLGA 65:35 solid and hollow fibres represent a novel, reproducible formulation for encapsulating higher amounts of cisplatin for an equivalent mass of excipient than other polymer formulations. The fibres developed in this study were able to maintain elevated concentrations of unbound cisplatin in the presence of a biological matrix for approximately 100 hours in vitro.

This thesis describes a number of studies of microstructured optical resonators, designed with the aim of enhancing the performance of organic semiconductor lasers and exploring potential applications. The methodology involves the micro-engineering of the photonic environment in order to modify the pathways of the emitted light and control the feedback mechanism. The research focuses on designing new organic microstructures using established semi-analytical and numerical methods, developing fabrication techniques using electron-beam lithography, and optically characterising the resulting structures. Control of the feedback mechanism in conjugated polymer lasers is first investigated by studying Distributed Feedback or photonic crystal resonators based on a square feedback lattice. This study identified the diffraction to free space radiation as a major source of loss in current microstructured resonator designs. By cancelling the coupling to free space through the use of different feedback symmetries and diffraction orders, a threshold reduction by almost an order of magnitude is demonstrated. The introduction of mid-gap defect photonic states in an otherwise uniformly periodic structure was studied in Distributed Bragg Reflector (DBR) resonators. This enabled GaN diode pumped polymer lasers to be demonstrated, indicating that the transition from complex excitation sources to more compact systems is possible. Devices for potential applications in the field of optical communications are also explored by demonstrating a polymer DBR laser based on silicon. In this way, the potential for integrating conjugated polymers with silicon photonics is confirmed. Photonic crystal fibres, which have a periodic microstructure in the transverse direction, are explored as an alternative means for controlling the optical properties of organic lasers. Fluidic fibre organic lasers were demonstrated as efficient sources with good spectral purity. In these devices, mechanisms to tune the emission wavelength were explored and the origin of the frequency selection mechanism was investigated.

The use of fibre-reinforced polymer matrix composite materials is growing at a faster rate than GDP in many countries. An improved understanding of their processing and mechanical behaviour would extend the potential applications of these materials. For unidirectional composites, it is predicted that localised absence of fibres is related to longitudinal compression failure. The use of woven reinforcements permits more effective manufacture than for unidirectional fibres. It has been demonstrated experimentally that compression strengths of woven composites are reduced when fibres are clustered. Summerscales predicted that clustering of fibres would increase the permeability of the reinforcement and hence expedite the processing of these materials. Commercial fabrics are available which employ this concept using flow-enhancing bound tows. The net effect of clustering fibres is to enhance processability whilst reducing the mechanical properties. The effects reported above were qualitative correlations. Gross differences in the appearance of laminate sections are apparent for different weave styles. For the quantification of subtle changes in fabric architecture, the use of automated image analysis is essential. Griffm used Voronoi tessellation to measure the microstructures of composites made using flow-enhancing tows. The data was presented as histograms with no single parameter to quantify microstructure. This thesis describes the use of automated image analysis for the measurement of the microstructures of woven fibre-reinforced composites, and pioneers the use of fractal dimensions as a single parameter for their quantification. It further considers the process-property- structure relationships for commercial and experimental fabric reinforcements in an attempt to resolve the processing versus properties dilemma. A new flow-enhancement concept has been developed which has a reduced impact on laminate mechanical properties.

The aim of this work has been to investigate various carbon materials, primarily cokes and fibres for use as negative electrodes in lithium-ion batteries. Chapter One presents an overview of the various batteries, both primary and secondary, currently available commercially. It also covers intercalation chemistry and carbon in its various forms. Some alternative negative electrodes are also discussed. Chapter Two details the experimental procedures used throughout the course of this thesis together with cell design and choice of materials used. Chapter Three presents the rationale behind the procedures described in Chapter Two. Investigations of various electrode materials, electrolytes and cell designs are presented with a view to obtaining the optimum procedures for use throughout the remainder of this thesis. Chapter Four presents an extensive study of single cycle experiments carried out on a variety of electrode composites containing various quantities of coke, carbon fibre and carbon black conductivity additives. It has been shown that the first cycle is very important in determining the usefulness of electrode materials for multiple cycle experiments. It has also been shown that particle size and the quantity of conductivity additive within the electrode composite has a significant effect on the performance of the electrode. A new, high surface area, carbon fibre, SA86, has been studied and it has been shown that the surface area has a detrimental effect on the cycling behaviour of this material. The affect that interparticle contact has on the capacities of fibrous electrodes has been demonstrated. Scanning electron microscopy has been used to probe the degradation that these electrodes suffer during the course of the insertion-extraction cycle and a method of presenting the insertion data has been used to show regions of lithium plating. A preliminary study of the diffusion coefficient of lithium within these electrode composites, calculated from the insertion data, has been undertaken. Chapter Five uses the results from Chapter Four to aid in the choice of electrode composites that will be cycled a number of times. It has been shown that by raising the lower potential limit to values above the lithium plating region, cycling efficiencies of 99% can be obtained over multiple cycles. It is also evident that the better fabricated, preprepared electrodes have higher capacities and cycling efficiencies than those that have not been ball-milled. Chapter Six summarises the work presented in this thesis and touches upon further work that can be carried out to complement the results obtained.

The auditory efferent system consists of two populations of fibres. The lateral system connects with the inner hair cells and the medial system connects with the outer hair cells. Past work has suggested that the efferent system may act via the action of the outer hair cells to control cochlear mechanics and, in doing so, contribute to the high degree of frequency selectivity observed in the auditory system. This hypothesis has not, in the past, been fully examined in humans. In this study, normally hearing human subjects were examined to see if there was a link between efferent activity and frequency selectivity. The first experiment investigated whether there was a link between efferent action and frequency selectivity at 1kHz. Efferent activity was assessed using the contralateral suppression of transient and distortion product otoacoustic emissions (OAEs). Emissions were evoked by tones and clicks and suppressed by contralateral white noise, narrow band noise and tones. The suppression was examined in specific frequency bands as well as over the entire response range. Frequency selectivity was estimated using the notched-noise masking technique and 'roex' filter shape modelling. No conclusive relationship was found. The possibility that the efferent system might play a part in frequency selectivity only when activated by the contralateral ear was considered by testing the auditory filter during contralateral white noise. No consistent relationship was found between efferent function, and either the 1kHz filter shape measured during contralateral stimulation, or the change in filter shape. However, contralateral white noise did cause a significant broadening of the 1kHz filter via what was thought to be the action of the efferent system. The timing of the onset of the contralateral efferent effect was examined using OAEs in order to allow stimulus timings to be set so that the efferent system would be effective during filter shape testing. The onset latency was found to be between 17 and 20ms. Further analysis of the auditory filter shape during contralateral stimulation was undertaken by stimulating the contralateral ear with narrowband noises at 500Hz, 1kHz and 2kHz. This also provided no clear proof of a link with efferent activity. Finally, the filter shape at 2kHz was considered. Significant relationships emerged between the shape of the filter and the activity of the efferent system in this region. This implied that efferent control of frequency selectivity is not constant over the length of the basilar membrane. Overall, the effect of the efferent system on frequency selectivity in normally hearing humans was not found to be straightforward, and was found to vary with frequency. However, the results were consistent with the theory that the medial portion of the efferent system acts in such a manner as to dampen the motion of the basilar membrane.

I set about exploring the history of Jambi batik with a view to establishing its nature, characteristics, methods of manufacture and function in its social context. A central aim of the study was to establish an accurate description of batiks from Jambi which could serve as a guide to museum cataloguers. In particular I planned to clarify the position regarding the red batiks. During the course of my investigations, I came across a similar confusion surrounding a group of batiks containing Arabic calligraphy. A further purpose of the study was then to determine which, if any, of these calligraphy batiks were made in Jambi. For those which did, my intention was to discover how they fitted into the social and economic context in which they were produced. This study has challenged a number of assumptions which have been made about batik in Indonesia. I have confronted static models and others which have focussed too narrowly on Javanese techniques and meanings. I have demonstrated the importance of approaching textiles from a perspective which recognises change and diversity. I have tried to emphasise the need to understand the central role of trade and colonial experience in relation to textiles in South-East Asia. I have also shown the need for taking into consideration the wider geographical context, beyond the Indonesian archipelago and beyond the notional boundaries of South-East Asia. Previous studies of Indonesian batik have tended to apply Javanese models to all of Indonesia. Indonesia was viewed with Java as the centre and the other regions as satellites to it: a Java-centric model which has marginalised batiks from Jambi. Finally, I believe I have shown the crucial importance of studying the technical aspects of textiles. Many other studies of textiles in South-East Asia have employed an anthropological perspective focusing almost exclusively on the symbolic to the neglect of the technical. This has resulted in a paucity of information which could help museum curators to identify both how and where the textiles were made. This lack of information made the study of textiles from Jambi, as it must do for many other marginalised places, particularly difficult. I hope that this study has not only revealed this problem, but has gone some way to remedy it.

The harmful impact of disposed plastics on the environment has become of increasing concern and this has led to the development of environmentally benign ‘green’ polymers. PHBV is one such green polymer that offers biodegradability and renewability, however its mechanical performance is quite limited. This can be improved by reinforcement with natural fibres to form green composites, which offer better mechanical properties while retaining biodegradability. In this work, the mechanical, thermal and biodegradation properties of PHBV/30 vol.% unidirectional flax, both untoughened and toughened with PBAT and ENR, were studied. Composites were prepared by compression moulding matrix powder interleaved with unidirectional flax fabric. The toughening agents were cryoground and mixed with PHBV powder prior to moulding. The addition of 30% unidirectional flax to PHBV produced very substantial increases in the tensile modulus, tensile strength and impact resistance, with values of 16.9 GPa, 183 MPa and 42 kJ/m2, respectively, being obtained. The inclusion of PBAT did not affect the mechanical properties except for some reduction in flexural strength. The inclusion of ENR produced significant increases in impact resistance but reductions in tensile and flexural properties due to a change in failure mode. The biodegradability of neat PHBV was minimal but was increased markedly by addition of flax fibres. The toughened composites showed a faster degradation rate than untoughened PHBV/flax, with PHBV/ENR/flax composites having the highest rate. The properties of the composites were superior to those of conventional plastics used in applications such as computer and mobile phone casings, which indicates potential suitability of this class of materials for these applications.

Abstract: Inflammatory bowel diseases (IBD) are a group of chronic inflammatory conditions including ulcerative colitis (UC) and Crohn’s disease (CD) induced by an interaction between genetic susceptibility, environmental factors, dysbiosis of gut microbiota and an abnormal mucosal immune response. Alternative therapies, such as probiotics, prebiotics and dietary fibre supplements (PPF) are cost-effective, have fewer side effects and can alter the microbial composition of the gut to favour a decrease in gut inflammation. However, these products are relatively understudied with a lack of data on usage patterns. This study aimed to determine factors related to use and awareness of PPF in patients with IBD. A cross-sectional study was conducted in patients with a diagnosis of inflammatory bowel disease in the University of Alberta IBD clinic. Using a 20-item survey questionnaire, data on use and awareness of probiotics, prebiotics and dietary fibre supplements and demographic information of their users were collected. Clinical characteristics such as occurrence of flares, age at diagnosis, clinical scores of severity, presence of extra-intestinal disease and objective markers of disease, were collected from charts. Survey questionnaires were completed by 267 participants with IBD. Ninety-one percent of IBD patients had heard of PPF in their lifetime. Awareness of PPF was associated with female gender (p

Processes causing crop establishment damage from ammonium (NH4+) fertilizer placed in close proximity to seed at sowing are generally poorly understood within farming communities of eastern Australia. Currently, the information used to assess establishment hazard includes nitrogen (N) tolerance for a limited range of crop species. Other factors include the N concentration of fertilizer products, with adjustment of the rate expected to be tolerated on the basis of soil moisture and application equipment. Current recommendations were adapted from North American research spanning a period from the start of the century until the 1990s and some recent Australian research (1960s to 1980s) for a limited range of crops and fertilizer types. The incidence of seedling damage from N fertilizer and fertilizer containing other nutrients appears to have grown in recent years. This may be attributed to use of a wider range of NH4+ and other fertilizers, a trend for at-sowing application in zero-tillage and expansion of areas of declining soil fertility, particularly N fertility. Other factors include the sowing of new crops with greater fertilizer sensitivity, low tolerance to establishment loss for high value genetically modified seed and modern designs of sowing and application equipment. The major objective of this research was to investigate ammonia (NH3) tolerance of 10 crop species of importance for eastern Australian cropping systems (maize, Zea mays L.; cotton, Gossypium hirsutum L.; wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; chickpea, Cicer arietinum L.; sorghum, Sorghum bicolor (L.) Moench; canary, Phalaris canariensis L.; canola, Brassica napus L.; panicum, Setaria italica L. and sunflower, Helianthus annuus L.). Experiments were designed to highlight differences among crops in NH3 toxicity and osmotic damage potential for commonly used NH4+ fertilizers. Various strategies were then tested to maintain plant populations within commercially acceptable ranges when affected by NH3 toxicity and/or high osmotic pressure. Tolerance of seeds to NH3 toxicity was evaluated in the field and for atmospheric exposure. Response of various crop species to atmospheric-NH3 exposure showed that certain species responded differently in their germination, coleoptile growth and radicle growth in a closed system. Using these 3 parameters as indices of crop response to NH3 toxicity revealed different ranking for some species; the same species showed a different critical NH4+ concentration for each parameter. Exposing seeds above 200 x 10-4 M NH4OH for 72 h was sufficient to significantly reduce or inhibit germination of all 10 species tested. Seed of most species were unaffected by exposure above 20 x 10-4 M NH4OH. Species rank, combining tolerance for germination, coleoptile growth and radicle growth was established to relate to likely performance in the field. Decreasing order of tolerance for monocot species was: maize > sorghum > wheat = barley > panicum > canary and for dicot species chickpeas > cotton > sunflowers > canola. A range of physical and chemical seed characteristics was correlated with NH3 tolerance to investigate tolerance mechanisms. For monocot species, tolerance was related to the seed surface area/volume ratio suggesting that diffusion resistance was an important parameter whereas for dicot species N concentration of seed was negatively correlated with tolerance. In field experiments where NH4+-fertilizers were placed with seeds, difference between species in their tolerance of atmospheric-NH3 was insufficient to describe effects of NH4+-fertilizers on crop emergence. Crop species fell into 3 response categories; high (maize, sorghum, barley and wheat), medium (cotton, canary and sunflower) or low (canola, chickpea and panicum) tolerance to soil NH4+-N. Soil NH4+-N concentrations tolerated by the medium and low tolerance group was 50 % and 15 to 25 % respectively, that of the high tolerance group. Generally, NH3 tolerance response for species such as wheat, barley and sorghum was found similar to current recommendations for urea (~0.5 g/m N as urea) but there were significantly different responses to NH4+-N from different NH4+-fertilizer products, that are not recognised in current recommendations. Crop species were ranked for sensitivity to mono-ammonium phosphate (MAP), di-ammonium phosphate (DAP), triple superphosphate (TSP), urea and ammonium nitrate, and categorised according to the fertilizer rate at which significant establishment damage occurred. Ranking of crop species for NH3 toxicity was generally similar across experiments but the NH4+-N rate tolerated varied with experimental conditions. Urea and DAP caused larger reductions in establishment than equivalent NH4+-N rates from MAP or ammonium nitrate. The "safe" rate for ammonium nitrate (1 g/m NH4+-N) was approximately twice that of urea at equivalent NH4+-N rates. Usually between 20 and 30 % more NH4+-N was tolerated for MAP than for DAP. In the absence of NH3 toxicity, osmotic effects of fertilizer products delayed and occasionally inhibited germination. There was significant difference among species in osmotic tolerance; cotton, maize and sorghum (< -0.3 MPa) were more tolerant than sunflower or soybean (> -0.2 MPa). Strategies to improve crop establishment in the presence of NH4+ fertilizer such as increasing seeding rate, adding water to the seed furrow, changing fertilizer N source and chemically modifying hydrolysis of urea were identified and tested. For low to moderate rates of seed placed NH4+-N, increasing barley seeding rate from 25 to 40 kg/ha was found to be successful strategy to maintain establishment when urea rate was increased from 1.1 to 2.3 g/m of seed row. Changing the fertilizer N source and modifying hydrolysis of urea were successful in lowering soil NH4+ around the seed and thus reducing establishment losses, but osmotic effects also limit the maximum fertilizer application rates. The added cost of these strategies may prevent their widespread adoption. Complex interactions between crop species, fertilizer product, soil texture and moisture, and application equipment highlighted by the results of these experiments, suggest that simple decision tools are insufficient to provide fertilizer recommendations that meet the demands of modern agriculture. A computer based decision support programme, Fertsafe, was developed during this study from experiments conducted and papers reviewed, to provide "safe rate" recommendations to apply fertilizer at sowing for a range of crop species, fertilizers, soils and sowing conditions of eastern Australia. Changes to fertilizer application equipment, other crops and fertilizer products will require ongoing research continuously improve and update this decision support tool.