This thesis investigates the structural and physical effects of changing the ratio of Mn:Ga in the anion deficient perovskite, YSr\(_3\)Mn\(_{4-x}\)GaxO\(_{10.5}\). YSr\(_3\)Mn\(_{4-x}\)GaxO\(_{10.5}\) crystallises in the tetragonal space group I4/mmm, with lattice parameters a~7.64 Å and c~15.66 Å. Magnetic characterisation indicates that the material is antiferromagnetic overall, with ferromagnetic ordering in the [001] direction of the unit cell. Earlier work on the structural analogue, Y\(_{1.07}\)Sr\(_{2.93}\)Mn\(_{2.67}\)Ga\(_{1.33}\)O\(_{10.5}\), identified a magnetic peak in the neutron diffraction pattern that could not be fitted following refinement of NPD data. This work concluded that the extra peak was due to a small MnO impurity. The effects of oxidation and fluorination on the structural and physical properties of YSr\(_3\)Mn\(_{4-x}\)Ga\(_x\)O\(_{10.5}\) with various Mn:Ga ratios are investigated. The physical and structural effects of substituting Mn\(^{3+}\) or Co\(^{3+}\) for Fe\(^{3+}\) in the perovskite related material, Pb\(_4\)Fe\(_3\)O\(_8\)Cl, have been investigated using XRPD, NPD and magnetic susceptibility measurements. An earlier characterisation of Pb\(_8\)WO\(_{10}\)Cl\(_2\) suggested a deficit on all atom sites within the unit cell. This work suggests a different structure with an intact cation and main oxygen sub-lattice. The site of an additional oxygen was established linked to tungsten. Pb\(_8\)WO\(_{10}\)Cl\(_2\) crystallises in space group I4/mmm, with a = 3.9846(2) and c = 22.690(2) Å.

As a result of numerous advantages over glass based devices, flexible displays continue to gather momentum. Many problems associated with fabrication of devices on polymers have been overcome, but the detrimental effect of water permeation through these substrates due to defects is still prevalent despite attempts to block pinholes with thin film barrier materials. A rigorous study of film defects using atomic force microscopy (AFM) plus novel application of the calcium test, with additional scanning electron microscopy and white light interferometry data has been undertaken. While pursuing this study, new methods of displaying defect data were discovered, allowing the problem to be visualised better. In addition, the results demonstrated that the major cause of device failure was point defects in the barrier films caused by airborne dust which adheres to the film surface before application of the barrier. The calcium test was applied in new ways to demonstrate the damaging influence of these film defects. To explain the results, a new model of permeation was devised through quantative analysis of the defects present on industrially produced films and confirmed using model substrates and a synthetic model, to explain the behaviour observed in the literature, but never previously explained. The conclusion was that the combination of AFM study, calcium testing and theoretical modelling gave improved understanding of the defect problems in flexible display devices. It is expected that the findings of this work will help DuPont Teijin Films to eliminate such flaws from their manufacturing process, ultimately allowing the films to be applied to commercial applications.

Ice cream is a popular, yet complex, multi-phase/colloidal foodstuff. To understand how this complex microstructure influences the eating behaviour of the consumer requires an interdisciplinary collaboration between Chemical Engineering and Psychology. Thus, an understanding of how product formulation affects consumer preference could be derived and could possibly be used for either product reformulation or promotion. Experiments explored and quantified the physical properties of the ice cream and how these structures translated into the sensory qualities within the human participants. This involved measuring the consumer’s preferences and the potential satiating qualities from different formulations. Destabilisation times of basic emulsions were also examined. The in-depth examination of the eating behaviour of ice cream used an universal eating machine. This showed, that regardless of formulation quality, the rate and total amount consumed remained relatively constant. This counter-intuitive result also persisted over repeated exposures to the product. By manipulating the physical structure of the ice cream (ice crystal phase through temperature manipulation), an understanding of the limits of oral sensitivity, and consumer perception of an altered product could be gained through a triangle test. These “human” results were contrasted to “machine data” (engineering measurements) gathered in the laboratory. The ice creams differed most markedly in their tribological responses. However, overall, the human panelists were insensitive to these clear physical differences in the test products.

The demand for reconstructive orthopaedic implants continues expanding at a reasonable pace as the incidence of fracture injuries and infectious diseases rises. There has been an increase in the clinical need for more effective synthetic bone graft materials due to the drawbacks of autogenous grafts. Since the 1980’s calcium phosphate cements (CPC’s) have attracted a great deal of interest due to their chemical similarities to natural bone; chemical, physical and mechanical characteristics have been investigated and manipulated to maximise osteoconductivity and osteointegration of these CPC’s since the start of their commercialisation. Here in this thesis, a series of investigation are complied to demonstrate novel and inventive approaches to expand the application of CPC’s: (1) limiting the liquid phase in the setting reaction of a brushite cement to produce monetite (dehydrated brushite) based cement, with increased solubility to overcome the problems faced by long term stability of hydroxyapatite (HA) cements; (2) manipulating the cement formulation to produce a cement that can set on a change in temperature, upon implantation, increasing handling time during surgeries; (3) incorporating therapeutic molecules to eliminate secondary surgeries following infectious diseases; (4) to enhance osteointegration of CPC’s by synchronising the degradation to natural bone formation. Results exhibit compressive strength appropriate for the application of cranioplasty; long term ageing studies demonstrates that the novel cement formulations do not hydrolyse to HA, eliminating the risk of catastrophic brittle failure that is commonly associated with CPC’s.

The aim of this study was to create a bi-layered packed bed chromatography support for the purification of nano-sized bioproducts. The effect of three different chemistry approaches, different solvent conditions, and microwave heating were investigated on construction of a bi-layered support. Sepharose CL-6B was activated with allyl glycidyl ether (routes 1&2). The inert outer layer was created in route 1 by reacting bromine with the allyl groups at the surface, followed by the addition of sodium hydroxide. Creation of the outer layer in route 2 was achieved by oxidation of surface groups with potassium permanganate. In both synthesises the allyl groups remaining were reacted with bromine and a charged amine ligand was coupled to the inner core. The activation step of route 3 resulted in the introduction of three membered epoxide groups throughout the support. Surface groups were reacted with sodium hydroxide or hydrochloric acid. Finally a charged amine ligand was coupled to the support by reacting trimethylamine hydrochloride with the remaining epoxide groups. Supports created by route 1 eliminated 91% of plasmid DNA binding whilst maintaining a high protein binding capacity. This was achieved by using DMS0 as the solvent in the bromination step and employing microwave heating. Route 2 proved to be the least successful in creating a bi-layered support. The beads created under hydrochloric acid-methanol conditions (route 3) reduced 91% of the plasmid DNA binding whilst maintaining a high protein binding capacity. This study revealed that microwave heating was a useful tool in the synthesis of chromatography supports. Subsequently, a comprehensive study was untaken investigating the effects of microwaves on numerous chromatography matrices.

Chocolate is consumed in large quantities, but is high in fat and calories, and has limited nutritional benefits. Producing reduced-fat chocolate offers a way of reducing energy consumed, if the consumer will accept the product. The aims of the research presented in this thesis were: i) to investigate consumer response to reduced-fat chocolate; ii) to investigate formulation routes for producing a reduced fat chocolate. Focus group data indicated ambivalence towards chocolate, with some negativity towards the concept of a reduced-fat indulgent product. By manipulating label information it was shown that whilst consumers expected to like chocolate labelled ‘reduced-fat’ less than the standard chocolate, ratings of actual liking and of sensory attributes were similar. Thus, personal experience plays a greater role than expectations. This suggests that if the sensory characteristics of a reduced-fat chocolate can be matched to a standard chocolate, actual liking should not be affected. Packaging concepts indicated how different components of the package affect liking. Water in oil cocoa butter emulsions were produced using a high shear mixer and a margarine line. Formulation changes (emulsifier type and concentration, and gelatin concentration) and processing parameters (shaft speeds and temperatures, and flow rate) were considered. All emulsions had small droplets (typically 1-5μm) and little ‘free water’. When produced on the margarine line fat crystals in polymorphic form V were produced. Crystalline shells were also observed at the droplet interface. Pilot plant experiments resulted in comparable emulsions, with small droplets and fat crystals in form V. Although a full chocolate was not produced, the potential for margarine technology to produce a reduced-fat chocolate was demonstrated.

A tubular reactor was designed and constructed in order that the decomposition of hydrocarbon gases and vapours could be studied. Product distributions and kinetic data obtained from the cracking of n-butane agreed with the values available in the literature. Prom these results a reaction mechanism for the thermal decomposition of n-butane was proposed. The cracking of 2,2-dimethylbutane was investigated and a reaction mechanism postulated following the acquisition of product spectra and the calculation of kinetic data. This mechanism differed from others found in the literature. Base etioporphyrin was synthesised by two unrelated routes. A concentrate containing approximately two per cent petroporphyrins was isolated from Tia Juana Pesado topped crude. After demonstrating that porphyrins are thermally stable up to a temperature of 5^0 G the effects of nine different porphyrin species towards the cracking of 2,2-dimethylbutane were examined. All nine were shown to act as cracking catalysts. Following consideration of the product distributions and kinetic data obtained from the study of porphyrin catalysis a reaction mechanism has been proposed. This is based on increasing the rate of homolytic bond cleavage. Porphyrins were shown to catalyse the decomposition of 1-hexene over the temperature range 325 to 450°C. At a temperature of 150°C three porphyrins catalysed the hydrogenation of 1-hexene.

The effects of adjusting the initial carbon to nitrogen (C:N) ration and pH of pig manure and straw mixes on ammonia emissions and pathogen marker inactivation during composting were investigated by experimentation and modelling. Three, 210-litre reactors were designed and built to control conditions, such as the maximum operating temperature, minimise temperature gradients and enable analysis of the off-gas for ammonia, water, oxygen and carbon dioxide. Respirometry showed that the optimal temperature for composting pig manure was about 60°C. A simulation model suggested that ammonia emissions could be reduced by lowering the initial pH and increasing the initial C:N ratio of the organic material. Experimentally, lowering the initial pH significantly reduced ammonia emissions. The effect of the initial C:N ratio on ammonia emissions was not significant because of variations in the pig manure. Pathogen markers were sometimes detected after composting from experiments with low ammonia emissions, so questioning the established criteria for pathogen inactivation. Experimental data validated the model, which simulated organic material decomposition using first order reaction rate kinetics and predicted the temperature and ammonia emissions profiles from initial conditions.

Mechanical properties of the plant cell wall are important in many industrial applications including biofuels, food quality and biotechnology. The plant cell wall consists of a network of cellulose microfibrils cross-linked with hemi-cellulose and interpenetrated by pectin. It is known that changes in the composition and architecture of the cell wall lead to detectable differences in the mechanical properties, but the relationship is not yet fully understood. In this work, three cell wall mutations of Arabidopsis thaliana, ida, mur1 and qua-2 (Snakeskin/sks), were compared to the Columbia (col0) wild type. Shoot and root growth were characterised to evaluate the effects of the mutations on plant growth. The ida mutation behaved like col0, with mur1 and sks showing increasingly severe effects of mutation on growth. Cells were also grown in suspension culture and an investigation of the wall components of both plant tissue and suspension cultured cells was conducted. An increase in pectin caused by the culturing process, and differences in cellulose content due to the mutations were found. The mean force required to break the suspension cultured cells (the rupture force) and deformation at rupture were obtained by compression testing. Force-deformation data from cell compressions were mathematically modelled up to deformations below the elastic limit of the cell walls, allowing the derivation of a low strain elastic modulus (E). Significant reductions in E for mur1 compared to col0 and ida and between sks compared to ida were observed. Similarities were drawn between the effects of genotype changes at both plant and single cell levels in that mur1 and sks were significantly different to ida and col0 for shoot, root and cell wall material properties.

Bone tissue continuously adapts to changes in mechanical load. This process can also result in a maladaptive ectopic bone response to mechanical insult, known as heterotopic ossification. The pathological differences at the molecular and structural levels are poorly understood. In vivo models exist but can often be too complex to allow isolation of factors which may stimulate disease progression. This thesis presents the development of a biologically self-structuring bone culture system using a fibrin gel which self-organises between two calcium phosphate anchors when seeded with cells. These bioinspired wound analogues are seeded with primary femoral periosteal cells - key players in bone repair and a range of pathologies- and develop longitudinally over time, allowing to study the temporal evolution of bone mineral and microstructure in excess of a year. Raman spectroscopy and XRD revealed that the mineral was hydroxyapatite and associated with collagen, which was organized like the in vivo tissue. The initial stem cell population differentiated to the terminal osteocytic phase, was linked by longitudinal canalicular networks (demonstrated using nanoCT) and remained viable over the year of culture. This work also demonstrated that pharmacological compounds can prevent the progress of ossification, displaying promise for applications in drug screening.