Hydrolysis, esterification and transesterification reactions were conducted in different reactor configurations, with the overall objective of enhancing the fundamental knowledge of Free Fatty acids (FFA) and biodiesel production, while providing key processing parameters and kinetic models for process design. Hydrolysis and esterification reactions were conducted in a non-catalytic continuous flow reactor, esterification reactions in a stirred batch reactor and transesterification reactions in a state-of-the-art Downflow Gas contactor Reactor (DGCR). The DGCR was operated in batch mode with a recycle loop. All samples were collected as a function of time and the concentrations of FFA and Fatty Acid Methyl/Ethyl Esters (FAME/FAEE) were determined, using gas chromatography for FFA and FAME/FAEE and titration for FFA. Tested processing variables for each reaction were varied according to the reaction objectives and reactor limits. Extensive kinetic models for continuous flow and batch reactions were performed and rate constants were established. FFA are an important intermediate for several industrial applications. Non-catalytic continuous flow hydrolysis with the aid of subcritical water produced high quality FFA with a maximum yield of 92 % at 350 \(^0\)C, 20 MPa and 50:50 water oil volume ratio. Temperature, time and water/oil initial ratio were found to be significant factors in the hydrolysis reactions. However, pressure had a minor influence.

Vertical stirred media mills have been used to reduce the particle size of minerals such as calcium carbonate. In this thesis vertical stirred media mills are used to mill cellulose in order to produce microfibrillated cellulose. The cellulose is co-ground with calcium carbonate to produce FiberLean™, a patented composite invented at Imerys and used as a paper additive in order to increase the percentage of filler. In a batch laboratory scale vertical stirred media mill the effects of energy input, composition, media density and impeller tip speed on the characteristics of FiberLean™ and the effects of these variables on the media movement in the mill using Positron Emission Particle Tracking is also studied. At pilot scale the effects of media volume and flowrate on FiberLean™ and the Residence Time Distribution using a tower mill and a vertical stirred media mill were investigated. This thesis has helped to understand this new, innovative product and the effect of process variables on the quality of FiberLean™.

Successful transfer of multiphase catalytic reactions from laboratory to commercial scale depends on proper understanding of all the parameters involved. This thesis aims to further understand these aspects with regards to trickle beds. A detailed discussion of reaction kinetics, hydrodynamics and mass transfer is presented for three industrially important reactions. The catalytic hydrogenation of dimethyl itaconate was studied in lab-scale shake flask and transferred to continuous flow with recirculation in a trickle bed reactor (TBR). The TBR was operated in the trickle flow regime using the catalyst complex [Rh((R,R)-Me-DuPhos)(COD)]BF4 supported on ion-exchange resins and trilobe alumina. Under optimized conditions in the TBR, 99% conversion and enantioselectivity of up to 99.9% were achieved. After elimination of all diffusional resistances, the experimental data could be fitted well by means of a kinetic model based on the Osborn-Wilkinson reaction mechanism. The selective hydrogenation of 1-heptyne over a 2 wt. % Pd/Al2O3 catalyst was studied in a TBR operating in both batch recycle and continuous modes. Solvent selection and liquid flow rate were found to have a noticeable effect on reaction rate and selectivity. The concentration profiles were fitted according to a Langmuir-Hinshelwood kinetic expression. Under optimized conditions in the TBR, 100% selectivity to 1-heptene was maintained up to 84% conversion of 1-heptyne. The selective hydrogenation of soyabean oil over a 2 wt. % Pd/Al2O3 catalyst was assessed in a TBR operating in a batch recycle mode. Reaction temperature, hydrodynamics and oil volume were found to have a noticeable influence on reaction rate and selectivity. It was demonstrated that under proper reaction conditions, the composition of soyabean oil can be upgraded to produce base oils for lubricants.

A variety of stimuli have been explored in the last few decades to develop dynamic interfaces with biotechnological and biomedical applications, such as biosensors, point of care devices, cell behaviour control and tissue engineering. In this work, the use of an electrical stimulus was explored for the development of a smart switchable surface with the ability to, in an on-demand fashion, expose and conceal progesterone - an ovarian steroid hormone which plays a crucial role as a modulator of sperm function. In this system, an electric potential drives a conformational change in the surface bound peptide moiety with fast response time. Focus was given to the design of a device that could be used in assisted reproductive treatments and grown into a commercially marketable product. Whilst being developed for assessment of sperm quality and fertilizing potential, the application of this system can be widely extended as this approach can be applied to other relevant antigen-antibody systems, which have so far only been evaluated in static conditions. Fabrication of a micropatterned surface was performed and a novel method for orthogonal functionalisation of gold and glass was developed, where gold was functionalised with a polyethylene glycol thiol self-assembled monolayer (SAM) and glass was functionalised with a covalently bound poly-d-lysine layer for sperm cell attachment. In addition to the investigations on SAMs and mixed SAMs formed on gold, silicon and glass substrates, studies with fluospheres were also undertaken. These tools are aimed to be used for further studies with cells, namely the investigation of their response in terms of Ca2+ signalling, a key player in the regulation of sperm function.

The design and development of smart colloidal structures intended for molecular encapsulation and delivery of functional molecules is an area of intense academic and industrial interest. A major part of this area is focussed on stimulating molecular release using an external stimulus such as pH or temperature. Whilst controlled delivery technologies are a mainstay of the pharmaceutical industry, aligned industries that utilise formulation to deliver functional molecules are also targets for encapsulation technology implementation. This can be a key driver for ameliorating competition from generic manufacturers, as any resulting can patent protection can be applied to the formulation. Current approaches in colloidal encapsulation and molecular delivery have mainly been concerned with encasing and subsequent release of a single functional molecule. However, there is interest in being able to structure two or more functional molecules within a “simple” emulsion microstructure for dual release over different timescales. Within colloid science, emulsions offer significant potential in this area due to the potential for compartmentalisation within the multiphase components. This thesis focuses on the design and development of Pickering emulsions structured with two actives segregated within their microstructure. This was achieved through the fabrication of colloidal Pickering particles designed with the dual purpose of being both emulsion stabilisers and molecular carriers. The work ultimately combines colloid structure design, development and characterisation with molecular encapsulation and release studies.

Heat transfer enhancement devices have become widely accepted as a method of enhancing exchanger performance and changing duties to either improve output or meet new operating requirements. hiTRAN® wire matrix inserts consist of a number of loops wound around a central core consisting of two intertwined wires. These inserts see a number of applications inside industrial tubular heat exchangers. They work by removing the laminar boundary layer that is often a dominant resistance to heat transfer, and mixing it with the core flow. This thesis presents research undertaken into the performance characteristics of hiTRAN® inserts in single-phase turbulent flow. Cal Gavin Limited, the company that manufactures these inserts, identified a need for reliable heat transfer and friction factor data within the turbulent flow regime. In order to meet this need, a test rig was commissioned in the form of a double-pipe heat exchanger. This exchanger was used in order to obtain performance data for a wide range of the sponsoring company’s most common insert geometries, placed inside a number of tubes, with diameters ranging from 10 mm to 13/8 inch. The heat transfer and pressure drop data obtained from the test rig were analysed and empirical correlations drawn to describe performance for varying loop densities for each tube and insert geometry. These data were further analysed against the existing semi-empirical theory concerning the use of roughness and geometry parameters to describe friction factor and heat transfer in systematically-roughened channels. The current research has shown that the friction factor correlations may be adapted to incorporate a logarithmic relationship on the ratio of hydraulic diameter to coil pitch, in order to effectively determine the friction factor of hiTRAN® inserts for which this ratio is between 1 and 8. This represents the range of inserts for which the sponsoring company are regularly required to provide thermal designs. The heat transfer performance is shown to be effectively described by the existing analogy between friction factor and heat transfer, as applied to systematically-roughened channels. This thesis also proposes a number of positive commercial implications of the determination of these correlations for the sponsoring company. As well as giving a number of accurate empirical relationships and presenting a semiempirical correlation for the description of performance of hiTRAN® inserts, this work also investigates the effect of a number of geometrical parameters upon insert performance. These qualitative analyses provide an indication of how the optimum coil diameter varies with loop density for a given insert geometry, as well as considering the effect of both the number of turns applied in intertwining the core wire during fabrication, and of the strength of fit that the insert makes with the tube wall. A constant pumping power comparison is also presented, which considers the ratio of heat transfer for the enhanced tube to the heat transfer that would have resulted from the fluid being pumped with the same power through a plain empty tube. This analysis indicates the presence of an optimum pitch to coil wire thickness ratio, the presence of which is substantiated by consideration of the laminar boundary layer behaviour around hiTRAN® inserts. Finally, suggestions are made for how these qualitative analyses may be developed by future experimentation into determining an optimised insert, along with other proposals for further work on the test rig.

Aero engine turbine blades are commonly produced via investment casting methods utilising sacrificial ceramic cores during casting to provide internal features such as cooling channels. During the firing process the conversion of the main ingredient (amorphous silica) to β-cristobalite plays a significant role, as it directly affects the dimensional stability, shrinkage, and leachability of the core after casting. Dilatometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilised to evaluate common additives such as zirconium silicate and aluminosilicate. Zircon was found to act as a nucleation site with high temperature stability while aluminosilicate acts as a flux enhancing cristobalite formation rates. This understanding was utilised to mimic the performance of the formulation using both a novel engineered material and alternative naturally sourced silica. An innovative method was also developed utilising confocal Raman spectroscopy (CRM) and polarised light microscopy (PLM) for analysis of ceramic systems studied with a hot stage up to 1500 °C. Polarised light microscopy was shown to be favourable for analysis of crystal growth mechanisms and low temperature (≈250 °C) α-β cristobalite phase transitions. Developments in Raman spectroscopic technique enabled the location and crystallinity of devitrified amorphous silica (cristobalite) to be observed via a quasi-real time method, providing insight to the source, direction and corresponding crystal growth rates. The combination of analytical techniques has provided sufficient understanding to explain the role of key components in ceramic core formulations, which can be used to improve control and the predictability of the system during development and manufacture.

This thesis aims to advance the knowledge on the effect that particulates of dairy (whey protein) and non-dairy (tricalcium phosphate) origin have on the stability of foams. The production of whey protein particulates was investigated via two separate routes. The first involved the preparation of whey protein gels which were subsequently freeze dried and then milled to powders. The second made use of the technology of creating fluid gels, used so far with polysaccharide based colloids, to fabricate whey protein fluid gels. In both cases, the systems obtained demonstrated the ability to create foams with significantly higher stability than native whey protein. Fluid gel systems were identified as the most industrially relevant systems and the possibility to produce powder formulations from them was explored via employing two different methods, spray drying and agglomeration drying. Ultimately, the design of hydrophobic particles from non-dairy food grade materials and their ability to adsorb on the air/water interface and stabilise foams was studied. The hydrophobicity of tricalcium phosphate (TCP) particles was modified by electrostatically binding ionic surfactant (lauric arginate ether - LAE) molecules on its surface. The behaviour of the particle-surfactant systems in terms of foaming ability and stability was investigated.

Perfume-filled microcapsules (PMC) are intended to be used in personal care products to provide a pleasant smell to consumers after washing their hair. It is essential to understand the interactions between the PMC and the untreated and bleached hair. The discovery of the adhesion mechanism would provide insight into the strategies for enhancing the performance of PMC on hair. The mechanism of adhesion and retention of PMC on two types of hair fibres (untreated and bleached) and their surface modifications to enhance the adhesion were investigated and explained in this work. The main equipment used in the investigation were: an atomic force microscope (AFM), a parallel plate flow chamber (PPFC) and a shower replica. It was found a dramatically decrease of the interactions between the hair and the PMCs when the hair had been previously bleached. The hydrophobic interactions were considered the main mechanism for this reduction but also the electrostatic interactions and hydrogen bonding were not discarded as a route to improve the adhesion and the retention of PMCs. In order to improve the adhesion between PMC and human hair, different types of silicones and cationic polymers were used to coat the hair and the capsule. An improvement was found up to 400% using polyquaternium-7 or aminosilicone. The increase of the adhesion with these polymers confirmed the importance of hydrophobic interactions as the main driving mechanism but also the significant role of hydrogen bonding in the interactions between PMCs and hair fibres.

This thesis mainly presents the use of CFD modelling to investigate and optimise the MOCVD processes in fabrication of II-VI compounds – cadmium telluride (CdTe) and zinc oxide (ZnO). It gives insight in detailed process modelling and proves the ability of using CFD modelling, which accounts for the interaction between hydrodynamics and chemical reactions in the reactor, to accurately predict the growth rate and thickness uniformity. The growth behaviour of CdTe was investigated in a custom-made inline MOCVD reactor by analysing the influence of the operating process parameters, which involves (a) deposition temperature, (b) operating pressure, (c) total flow rate, and (d) the partial pressure ratio of precursors on the performance of the thin film (i.e. thin film deposition rates, thickness uniformity and material utilisation) in steady flows. The deposition of ZnO was studied in a bespoke horizontal reactor. Flow behaviour, heat transfer and mass transfer involved in the MOCVD reactor were discussed under different process parameters, with the objective to improve MOCVD process control. A thermal field calculation was implemented in the CFD modelling of ZnO deposition. A series of experiments of coating ZnO layers were performed to validate the simulation results. In addition, the analytical model, with reasonable simplifications and approximations for ZnO deposition, were further performed to get an intuitive insight into the mechanism governing the growth rate and uniformity in MOCVD processes. A good agreement was achieved through theory analysis, numeral simulation and experiment. The analysis of the transport phenomena under different process parameters in this study can greatly contribute to optimising the MOCVD equipment and processes, and to achieving the ultimate goal of a better growth rate, uniformity and controllability on thin film with economic use of precursors.