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.

Implementation of food safety programmes has been difficult for small and medium sized companies (SMEs) in Cyprus, taking into consideration specific practises witnessed as common place amongst Cypriot food producers. SMEs tend to have a poor understanding of food management systems and limited adoption and implementation. The requirement for full food management implementation and the replacement of the national standards by the new ISO22000 in 2006 placed an even greater burden on these businesses. The aim of this project is to compare food safety and hygiene before, during, and after implementation of food management systems assessing whether the implementation of food management systems in SMEs in Cyprus improves the hygiene and compliance with food safety requirements. A questionnaire survey was made of 50 SMEs (food industry sector) and an audit process was carried out, in companies that had not started the implementation of food management systems but intended to do so. Follow-up audits to the premises observed the process and the operatives to determine any changes to the level of food safety and hygiene. A benchmarking audit was carried out before, during, and after implementation of the system, and each company was rated. Results show that most respondents encountered many problems in applying and maintaining food management systems. Even if food management systems were applied, businesses did not alter their daily practices in a significant way. To conclude, in order for small food enterprises to have in place workable food management systems, a generic, simple, and flexible food management system must exist. In addition, each enterprise has its own application limit regarding the complexity of the system. When this limit is exceeded negative results appear for the enterprise.

Surimi is a concentrated myofibrillar protein added with several additives. It has been used by seafood industries as an intermediate product to produce various seafood analogues. Due to the current increase in health awareness, consumer demands healthier and less sweeter surimi. The objective of this study is to investigate the rheological and textural properties of surimi added with different types of additives which is sugar, salt and sago starch. This study is also done to determine the possibility of reducing the amounts of additives added to surimi. Sago starch as an additive to improve the rheological and textural property of surimi is studied. Another concern in the surimi industry is the washing process. The 3 washing cycle procedure produces large amount of water waste. Thus, this study is done to understand the effects of reducing the washing cycle and using nanobubble water on surimi. Results obtained from this research shows that mannitol yields the best results when compared to sucrose and sorbitol. Surimi with 4% (w/w) salt concentration yields the highest gel strength. However, surimi with 1% (w/w) salt concentration which possesses a lower gel strength showed frozen stability up to 6 months. Sago starch was found to increase gel strength up to 11 0%. Washing using medium concentrated nanobubble water ( 11.15 x 1 08 bubbles/ml) was found to display a high gelling strength with only 2 washing cycle compared to using distilled water.

This thesis aims to develop a better understanding of both the formation and properties of fluid gels using the microstructural engineering approach. In general terms, the two main outcomes of this research are: (1) advancing the knowledge on the structuring processes for fluid gel design and (2) developing new models for the structure-function relationship for fluid gels. There is currently a lack of understanding on the formation of thermo-stable fluid gels due to the absence of processing techniques for their production. In this thesis, two processing techniques were developed to produce thermo-stable fluid gels from alginates. The first technique is a continuous process comprising a pin stirrer device with a Ca2+-injection system. The second production technique used a cup and vane rheometer combined with an internal gelation method. With this technique, the kinetics of fluid gel formation was studied as function of applied shear rate, calcium concentration and alginate molecular weight. With regard to the structure-function relationship, the lubricating behaviour of agar fluid gels was explored using a new approach which consisted in decoupling the contributions of the continuous phase and the particulate gelled phase. The effect of added co-solutes on lubricating properties of agar fluid gels was also explored.

Minimisation of Pt loading in proton exchange membrane fuel cells (PEMFCs) is important because Pt is expensive and its supply is limited. Nanoparticle aggregation is a problem because aggregated nanoparticles have a lower surface area and so exhibit lower mass activity than well dispersed nanoparticles. In the present work platinum nanoparticles were successfully prepared, by an aqueous colloidal route, using tetradecyltrimethylammonium bromide (TTAB) and nonylphenolethoxylate (NP9). Such organic molecules which adsorb on the surface of nanoparticles are generally regarded as undesirable species which block catalytic sites and slow reaction kinetics. However, removal processes cause particle aggregation. Here the performance of catalysts was studied using a rotating ring disc electrode (RRDE), without extensive removal of surfactant. Nanoparticles prepared using NP9 surfactant showed catalytic activity for the oxygen reduction reaction (ORR) similar to the commercial catalyst (TKK) but TTAB had a strong poisoning effect. Finally the performance of the Pt+NP9 nanoparticles was compared with the commercial catalyst (TKK) using single cell MEA testing. The main difference in performance was in the mass transport region of the polarisation curve. The conclusion was that surfactant stabilization of Pt nanoparticles is important to fuel cell performance, while subtle effects of molecular structure on catalytic activity require more investigation.