This work concentrates on the selection and improvement of differential equation based models of the penicillin G fermentation. Published penicillin fermentation models have been reviewed and compared with regard to their abilities to predict fermentation behaviour, genetic algorithms have been applied to the design of optimal experiments for model parameter estimation, and a new approach to assessing the theoretical identifiability of model structures has been proposed. When applied to the best penicillin fermentation model yet found, this new approach suggests that the model's parameters are uniquely identifiable. The best performing model was shown to be a morphologically structured model for which measurement data related to the various morphologically distinct regions were obtained using image analysis. This model was modified to increase its speed of execution, and extended to describe fermentations where lactose was present in the inoculum. Design criteria from the field of optimal experiment design were combined with genetic algorithms as a technique for searching through the range of possible input combinations, subject to constraints on the fermenter operation, to develop experimental feed profiles. The theoretical identifiability of the fermentation model has been assessed for the first time, using a novel approach to identifiability testing which uses a symbolic mathematics package, along with subsequent post-processing, to determine almost at a glance whether or not a fermentation model should be uniquely identifiable.

In order to mitigate the effects of climate change and reduce dependence on fossil fuels, carbon-neutral methods of electricity generation are required. Solid oxide fuel cells (SOFCs) have the potential to operate at high efficiencies, while liquid hydrocarbon fuels require little or no new infrastructure and can be manufactured sustainably. Using hydrocarbons in SOFCs introduces the problem of carbon deposition, which can be reduced or eliminated by judicious choice of the SOFC materials, the operating conditions or the fuel itself. The aim of this project was to investigate the relationships between fuel composition and SOFC performance, and thus to formulate fuels which would perform well independent of catalyst or operating conditions. Three principal hypotheses were studied. Any SOFC fuel has to be oxidised, and for hydrocarbons both carbon-oxygen and hydrogen-oxygen bonds have to be formed. Oxygenated fuels contain these bonds already (for example, alcohols and carboxylic acids), and so may react more easily. Higher hydrocarbons are known to deposit carbon readily, which may be due to a tendency to decompose through the breaking of a C-C bond. Removing C-C bonds from a molecule (for example, ethers and amides) may reduce this tendency. Fuels are typically diluted with water, which improves reforming but reduces the energy density. If an oxidising agent could also act as a fuel, then overall efficiency would improve. Various fuels, with carbon content ranging from one to four atoms per molecule, were used in microtubular SOFCs. To investigate the effect of oxygenation level, alcohols and and carboxylic acids were compared. The equivalent ethers, esters and amides were also tested to eliminate carbon-carbon bonding. Some fuels were then mixed with methanoic acid to improve energy density. Exhaust gases were analysed with mass spectrometry, electrical performance with a datalogging potentiostat and carbon deposition rates with temperature-programmed oxidation. It was found that oxygenating a fuel improves reforming and reduces the rate of carbon deposition through a favourable route to CO/CO2. Eliminating carbon-carbon bonds from a molecule also reduces carbon deposition. The principal advantage of blending with methanoic acid was the ability to formulate a single phase fuel with molecules previously immiscible with water.

Expanded Bed Adsorption (EBA) is a form of liquid fluidized bed adsorption chromatography employing dense chromatographic media of defined size distribution. EBA's main advantage stems from its ability to perform chromatographic separations with crude feedstocks, thereby combining three separate tasks - clarification, concentration and initial capture/purification - in one single unit operation. Still, understanding of support particle movement (solid phase dispersion) is limited, impairing the process' robustness. In this work, the technique of Positron Emission Particle Tracking (PEPT) was employed extensively to study solid phase motion and dispersion in expanded beds of commercial media. In addition to providing evidence of classification and non-uniform bed expansion in all fluidised beds under study, PEPT was used to determine kinetics of bed stabilisation and identify changes in tracer position and speed along the length of the bed in response to variations in flow rate, degree of column misalignment, and means of fluid distribution. Furthermore, adsorbent particle motion was investigated under 'real process' conditions, i.e. during the application of a porcine serum feedstock.

Chemical and physical processing in the small intestine is an important step for food digestion and absorption. Having reviewed the literature, a relevant model has been developed which enabled investigation into the fluid flow, mixing mechanisms and delivery of nutrients to the wall of the model small intestine. Designing, developing and using the Small Intestinal Model (SIM), a physical model of a section of the small intestine, mimicking the physiological contractions, allowed mass transfer to be measured using different process conditions and ingredients. Experiments were carried out using the SIM to study mass transfer, starch digestion and flow visualisation. While simulating the small intestinal flow profile, experiments have shown that the functional ingredient guar gum reduces the mass transfer coefficient of the model nutrient riboflavin. This together with computational modelling suggests an explanation for the observed functionality of guar gum to reduce the peak increase in blood glucose levels after ingestion of test meals. Industrial implications are to give a scientific and engineered design methodology for novel food formulations by understanding the food product behaviour in the SIM. Optimisation of formulation candidates going to the human trial stage and improvement of speed to market of new product introductions is intended.

Blends of biodegradable polyesters; poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were produced by a variety of preparation methods; solution casting, melt blending and blending in the presence of carbon dioxide using a single screw extruder. The blends were characterised using scanning electron microscopy (SEM), mechanical testing, differential scanning calorimetry (DSC), Fourier Transform infrared spectroscopy (FTIR), rheology and size exclusion chromatography (SEC). Comparison of the blends produced via the different preparation techniques indicated that carbon dioxide was able to improve the morphology and mechanical properties of the PLA/PCL blends. The influence of carbon dioxide on the reptation time of poly(ε-caprolactone) was investigated using oscillatory rheology. It was shown that by introducing CO2 into the polymer melt, the reptation time was significantly reduced, providing evidence that CO2 was interacting with this polymer. Further analysis of the data showed that the activation energy to flow was reduced, which was consistent with the reduction in the reptation times. Flash DSC, a relatively new thermal analysis technique, was used to explore areas of polymer science that are otherwise unachievable using conventional DSC. It showed the ability to prevent reorganisation and crystallisation in partially crystalline polymers such as poly(ε-caprolactone) and was able to evaluate the activation energy of the glass transition temperature for different amorphous and partially crystalline grades of PLA.

In this project, we developed a real-time electrochemical mediator assay to enable the assessment of cell numbers and cell viability. It allows us to monitor metabolism calculable down to a single cell in a low cost easy to use rapid assay, as yet not possible with current technology. The developed assay is based on the determination of oxygen. This was made possible via the use of electrochemical mediator ferrocene carboxylic acid (FcA). The FcA showed distinctive catalytic properties in interacting with reactive oxygen species generated from oxygen when compared to ferrocene methanol (FcMeOH). A deeper insight into the chemistry controlling this behaviour is provided. The behaviour is then taken advantage of to develop a cellular aerobic respiration assay. We describe the properties of the FcA system to detect, in real-time, the oxygen consumption of Escherichia coli DH5α (E. coli). We demonstrated that the FcA-based oxygen assay is highly sensitive, and using a population of cells, oxygen consumption rates could be calculated down to a single cell level. More importantly, the results can be accomplished in minutes, considerably outperforming current commercially available biooxygen demand assays. The developed assay is expected to have a significant impact in diverse fields and industries, ranging from environmental toxicology through to pharmaceutical and agrochemical industries. A significant start has been made into optimisation of the system into a commercially marketable product, including much work on mediator immobilisation and electrode synthesis.

The purpose of the research was the investigation of the phase-inversion phenomenon in liquid-liquid dispersions by examining the various parameters that could affect it, trying to understand its mechanism and draw some general conclusions on the behaviour of liquid-liquid dispersions in relation to it. The experimental investigation of phase inversion was done by using two different methods to produce the liquid-liquid dispersions. In the first method, the dispersions were produced by shearing the liquids between two parallel plates, one rotating and the other being stationary. In the second method, the dispersions were produced by the turbulent flow of the liquids in a horizontal tube. Phase inversion was examined in relation to the properties of the liquids and the experimental conditions. It was observed visually in the first method and by examining the electrical conductivity of the dispersions in the second method. Following a general introduction to the phenomenon of phase inversion, a literature review of previous research work on the phenomenon is presented first, together with some theoretical aspects related to it. A detailed description of the experimental methods and materials used is presented next, followed by a brief theoretical analysis of the mode of flow of the liquids in the two different methods used. Finally, the results and correlations obtained from the experimental investigation of phase inversion are presented, followed by a detailed discussion and the conclusions drawn.

Driving force for this research is dictated by the fact that resources of crude oil, key source of energy in our Everyday life, are limited. Therefore the extensive work is currently carried out to find alternatives such as fully Synthetic fuels - Fisher Tropsch synthesis (FTS). Though FTS was developed in 1923 until recently it was Nearly forgotten. Recent prices of crude oil make this technology attractive again and new research aimed at Optimisation is necessary. The aim of this work was to investigate the behavior of different catalyst in gas/oil dispersion and the effect on Overall mass transfer rate. Efficiency of the entire synthesis, specifically, what is the effect of steam at those Conditions was investigated, since there is practically no information in open literature. This work shows summary of the similarities and differences of properties of all the investigated catalyst and Evaluation of their performance. It was shown that the interactions and ultimately the effect that particles have On the bubble size made of either polar or non-polar gas depends on the particles lyophobicity.

Mixing viscoelastic fluids is common to many chemical and biochemical process industries where the rheological properties of the bulk change considerably over the time course. The objectives of this study were to investigate the effects of viscoelasticity in mechanically agitated vessels (on: i- the power consumption and flow patterns in single phase and gassed systems, ii- mixing time under unaerated conditions and iii- cavities in the presence of gas) and to study the performance of InterMIGs in comparison to the classical six bladed disc turbines. Model viscoelastic fluids prepared exhibited only slight shear thinning properties (Boger fluid type), hence the effects of viscoelasticity could be studied in the absence of other rheological properties. Results obtained with these fluids were compared to those with viscous Newtonian glycerol covering the transitional flow regime (50< Re< 1000). Additionally, some work was also conducted in water for a preliminary characterisation of InterMIGs. In the relatively low range of Elasticity numbers (El < 3.5 x 10\(^-\)\(^3\)) covered, secondary flow patterns were not reversed. The power drawn under unaerated conditions was higher in viscoelastic fluids (at a given Reynolds number) for both impeller types that had to compete with mutually opposing viscoelastic forces. An experimental set-up to measure mixing times in viscous fluids (using the fluorescent dye-fibre optic technique) was installed. Reduced secondary circulations in viscoelastic fluids resulted in longer mixing times. Power consumption under aeration was also higher in viscoelastic fluids than that in Newtonian glycerol. Different from the findings under unaerated conditions, this enhancement was independent of the level of viscoelasticity. Cavities, hence the power drawn under aeration, were in general stable with respect to the variations in the gas flow rate in viscous fluids. This stability was found to be accentuated by viscoelasticity. InterMIGs underwent viscoelastic effects more severely on account of the complicated interaction of the viscoelastically driven flows with the flows associated with the inner and outer blades of these impellers. They presented a better choice in low and high viscosity Newtonian fluids and their performance was comparable to that of a single Rushton turbine in viscoelastic fluids.

This thesis concerns the thermal behaviour and isothermal crystallisation kinetics study of cyclic polyesters and its blends, in particular cyclic poly (butylene terephthalate) (c-PBT). The production of c-PBT is interesting; in fact it is different from production of conventional linear PBT since c-PBT is produced by in situ polymerisation of cyclic butylene terephthalate oligomers (CBT) in the presence of suitable initiators or catalysts. These relatively novel materials, i.e. CBT offer many advantages in properties and the most unusual and useful is that they can be processed at low viscosity (water like) and exhibit rapid crystallisation. The thermal behaviour and isothermal crystallisation kinetics of CBT and c-PBT were analysed. The most significant achievement of this project is blending where blends of c-PBT and styrene maleimide (SMI) were prepared by simultaneous in situ polymerisation and melt blending of solid dispersion CBT/SMI powder. This is unique and novel and the results show consistency and signs of miscibility although there are no external forces applied during the melt blending. It was found that the presence of 30 wt % and above of SMI impeded the crystallisation of c-PBT. This suggests that miscibility occurred. The miscibility of these c-PBT/SMI blends was support with the presence of a single composition-dependent glass transition temperature and negative Flory-Huggins interaction parameter. Studies on crystallisation kinetics of c-PBT were also done by Avrami analysis and using the Hoffman-Lauritzen theory. Previously there have been very limited studies of the crystallisation kinetics of PBT produced from its oligomer. Further work on crystallisation of c-PBT/SMI blends was also performed.