The depletion of fossil resources, the volatility of the oil price market and the urgency to mitigate the effects of climate change have pushed the development in chemical industry for sustainable, energy efficient and economic processes for fine chemical production. Selective oxidation of alcohols using noble metal catalysts is a key catalytic conversion for the production of carbonylic and carboxylic compounds for the chemical, pharmaceutical, automobile or consumer goods industry. Gold based catalysts, in particular, have demonstrated superior performance over commonly employed catalysts or stoichiometric oxidants. Challenges, however, remain to develop not only active and selective catalysts but with a long lifetime for industrial application. This thesis is based on the study and development of gold based catalyst systems for the selective oxidation of alcohols under mild conditions. The main model compound studied is the selective oxidation of salicyl alcohol to salicyl aldehyde and salicylic acid. Salicyl aldehyde is a very important chemical compound for the production of a range of fine chemicals and chelating compounds with an estimated market capacity of 4000-6000 tonnes/year. Reactions were carried out in a semi-batch stirred glass reactor under atmospheric pressure using air as oxidant and water as solvent. The setup successfully enabled the direct study of the kinetics and mechanism without influences of mass transport. Studies demonstrated the reaction followed sequential mechanism of first order with the consecutive oxidation of salicyl aldehyde to salicylic acid. The main catalyst system used was gold on powdered activated carbon, prepared by sol-immobilisation using Tetrakis(hydroxymethyl)phosphonium chloride (THPC) as stabiliser. 1wt% Au/C achieved maximum turnover frequency numbers (TOF) of 342 h-1 and selectivities of 79% towards salicyl aldehyde at 100% conversion. The increase in gold loading to 3wt% resulted in a decrease in activity caused by an increased gold particle size. The addition of Pd as second active metal showed the formation of an alloy and a decrease in activity with the increase in Pd amount. The application of the Au/C catalyst system for continuous processing was investigated using gold on granular carbon in a trickle bed reactor. Base-free selective oxidation of salicyl alcohol was studied via synthesis of MgO dispersed on oxides, in particular hydrotalcites. The basicity, measured by CO2 adsorption capacity, increased with increased loading of MgO. The catalysts showed potential activity, achieving 59% conversion with 90% selectivity towards salicyl aldehyde.

Cellular signalling networks are responsible for coordinating a cell’s response to internal and external perturbations. In order to do this, these networks make use of a wide variety of molecular mechanisms, including allostery, gene regulation, and post-translational modifications. Mathematical modelling and systems approaches have been useful in understanding the signal processing capabilities and potential behaviours of such networks. In this thesis, a series of mathematical modelling and systems investigations are presented into the potential regulation of a variety of cellular systems. These systems range from ubiquitously seen mechanisms and motifs, common to a wide variety of signalling pathways across many organisms, to the study of a particular process in a particular cell type - the cell cycle in Saccharomyces cerevisiae. The first part of the thesis involves the analysis of ubiquitous signalling mechanisms and behaviours. The potential behaviours of these systems are examined, with particular attention paid to properties such as adaptive and switch-like signalling. This series of investigations is followed by a study of the dynamic regulation of cell cycle oscillators by external signalling pathways. A methodology is developed for the study of mathematical models of the cell cycle, based on linear sensitivity analysis, and this methodology is then applied to a range of models of the cell cycle in Saccharomyces cerevisiae. This allows the description of some interesting generic behaviours, such as nonmonotonic approach of cell cycle characteristics to their eventual values, as well as allowing identification of potential principles of dynamic regulation of the cell cycle.

One of the challenges of current organic solvent nanofiltration (OSN) membranes is to improve permeability in polar and non-polar solvents without compromising selectivity. Here, the development of a new generation of OSN membranes: High flux Thin Film Composite membranes (TFC) via interfacial polymerization (IP), is proposed. This thesis offers a comprehensive study that analyses the relationship of OSN high flux TFC membrane formation and post-formation parameters, morphology, structure and surface polarity, to membrane functional performance in both polar and non polar solvents. The dissertation starts with the development of novel high flux TFC membranes for polar aprotic solvents to address the trade-off between permeability and selectivity. This is accomplished by using two different approaches: (a) incorporation of polyethylene glycol inside the pores of the support prior to the IP reaction, and; (b) post-treatment of the TFC membranes with an “activating solvent”. Subsequently, a detailed analysis of membrane performance and morphology, considering the aforementioned approaches was conducted, resulting in dramatically increased solvent fluxes without compromising rejection. Additionally, a detailed study to manipulate molecular weight cut-off (MWCO) of these TFC membranes was carried out and successfully achieved by using different amines in the IP reaction. Next, novel high flux hydrophobic TFC membranes via IP with tuned MWCO for non-polar solvents were developed, elucidated and studied. The surface properties of hydrophilic TFC OSN membranes were modified by capping the free acyl chloride groups on their surface with different monomers containing hydrophobic groups. A detailed study on surface polarity and membrane performance was undertaken, suggesting that surface chemistry plays an important role in solvent permeation. The membrane performance was compared to commercial OSN integrally skinned asymmetric (ISA) and TFC rubber-coated membranes. In the next stage of this thesis, the effects of different support membranes on TFC membrane formation and functional performance were studied for both polar and non-polar solvents. It was found that support membranes have an effect on TFC membrane formation and solvent permeation. Finally, to increase permeability even further without a requirement for treating the TFC membrane with an activating solvent, highly porous TFC membranes have been developed via IP by controlling the structure of the top layer at a molecular level. This was achieved by incorporating a monomer with a contorted structure during the IP reaction, resulting in a highly porous polymer network. It is believed high flux TFC OSN membranes prepared by interfacial polymerization may offer new degrees of freedom in membrane design, which could lead to the next generation of high performance OSN membranes.

Interests in application of organic solvent nanofiltration (OSN) technology based on synthetic membranes to molecular separation processes have been growing rapidly in recent years. The main classes of OSN flat sheet polymeric membranes are integrally skinned asymmetric (ISA) and thin film composite (TFC) membranes. A general goal of OSN membrane research is to improve membrane performance for specific non-aqueous applications, or to develop new separation processes. Most of the time the research is performed via trial–and–error methods, leading to extension of development time and increase of costs. This is partially because the structure of OSN membranes, particularly the size of their permeation pathway is largely unknown. The filtration characteristics are mainly determined by the membrane structure, which is dependent on various fabrication methods as well as polymer chemistry. However, a direct correlation between these factors has not been understood in detail, because the current characterisation techniques have limitations in studying polymer structures with dimensions at the macromolecular level. The pore size in nanofiltration (NF) membranes is believed to be less than 2 nm, which is a lengthscale at the edge of most available material characterisation techniques. For this reason, advanced methods to study the membrane morphology need to be explored or developed with the aim of elucidating the NF membrane structure, transport mechanisms, and to understand the relationship between the membrane structure and the separation characteristics. These objectives guided the work to development of a nanoscale characterisation method based on imaging the porous regions via probing the NF pores with nanoparticles (NP). Given that the probes provide high electron contrast, it is possible to map the pores formed between the polymer entanglements in the transmission electron microscope (TEM). This technique measures the pore size in situ, thus, a membrane is characterised during its operational state. The pore size was found to correlate well with the solute rejection and flux measured for a range of ISA and TFC membranes. The pore size distributions were then used together with a pore–flow model to simulate rejection curves. A further insight into the membrane structure, particularly the surface structure, was provided by atomic force microscopy (AFM), particularly phase imaging. This method was applied to characterisation of polymer packing at the membrane surface, leading to analysis of the correlations between the phase shift, filtration parameters and membrane preparation methods.

The objective of work described in this thesis was to synthesize water soluble polymers with drag reducing properties that would expand the understanding of the relationship between the molecular structure of polymers and drag reduction performance. The additional aim of this study was to identify suitable additives that would enable removal of associating polymers from the low permeability reservoirs. The copolymers of acrylamide and two hydrophobic monomers, n-decyl- and n-octadecyl acrylamide were prepared using micellar polymerisation. Polymers of N-hydroxyethyl acrylamide were also prepared via the same method. Water soluble polymers of styrene and butadiene were acquired by sulfonation of poly(styrene-block-butadiene) with acetyl sulfate. The evidence of the incorporation of hydrophobic monomers, sulfonic acid groups into copolymers and the concentration of hydrophobic moieties was studied using NMR, FT-IR and Elemental Analysis. The influence of the degree of sulfonation on the flexibility of polymers and polymer degradation temperatures were investigated by DSC, DMA and TGA. The associating properties of polymers were studied using Dynamic Light Scattering and rheology. The drag reducing properties were quantified using a standard rheometer equipped with a Couette double-gap measuring geometry, by calculating the percentage of drag reduction (% DR) based on apparent viscosity. The extent of adsorption and desorption of polymers from silica was studied by Total Organic Carbon. From the obtained results it was clear that the associating properties of polymers synthesised in this thesis were dependent on the concentration of hydrophobic moieties. In addition, the formation of hydrophobic associations and the polymer coil dimensions were found to greatly influence the drag reducing properties and shear resistance of copolymers. It was found that hydrophobically modified polyacrylamide promoted higher drag reduction in comparison to unmodified polyacrylamide. In addition, introduction of a small amount of hydrophobic moieties was found to impart drag reducing properties in poly(N-hydroxyethyl acrylamide). Moreover, water soluble sulfonated poly(styrene-block-butadiene) showed high drag reduction efficiency at extremely low molecular weights below the required lower molecular weight limit necessary to produce excellent drag reduction effect. Furthermore, the sulfonation of poly(styrene-block-butadiene) resulted in the reduced thermal stability of polymers and an increase in the degree of sulfonation resulted in the decrease in the flexibility of polymer chains. The extent of adsorption of polymers of acrylamide on silica was found to increase with molecular weight of polymers and was higher for hydrophobically modified polyacrylamide due to the formation of intermolecular associations between copolymer chains. The desorption capability of copolymers with the aid of Cyclodextrin was demonstrated and was found to depend on the type of Cyclodextrin used and on the concentration of hydrophobic moieties. Nearly 100 % of the adsorbed polymer was recovered when even small concentrations of β-Cyclodextrin were applied. Additionally, partial desorption of polyacrylamide with the aid of α and β-Cyclodextrin was also achieved.

Recent development in wireless communication technology offer new opportunities for wireless connectivity of field devices in industries such as oil and gas, chemical processing and water distribution. Wireless communications can assist these industries to improve plant knowledge by acquiring additional measurements from processes and equipment when wired communication would be infeasible. Requirements for a field communication network in the process industry include real-time support for mixed traffic, robustness, availability, security, reliability and scalability in a harsh industrial environment. Furthermore, to build such a network on license-exempt band raises concerns relating to its safety, security, performance and governance. Three specific issues have been addressed in this thesis. The first issue investigated is time synchronization which is necessary to ensure data integrity and determinism in network operations. The second investigation is the study of the performance of a closed-loop control application running over a resource-constrained wireless network. The need to ensure co-existence with the other wireless networks operating over the same radio band while offering predictability and reliability has added a new concern to the use of wireless technology in networked control systems. The third issue is to ensure longevity of wireless field nodes operated on standalone batteries which requires a mechanism to minimize energy consumption. This topic was addressed in an investigation into methods for transmission power control. The research presented in this thesis has discovered new ways to solve these problems. It has characterized their performance and implemented them in several practical demonstrations, including one field deployment. The thesis also provides an insight into the opportunities which wireless technology offers, the challenges which it encompasses, and gives a review of key emerging wireless networking technologies relevant to process automation. Finally, it offers an opinion about the future directions of wireless communications in the process industries.

This thesis describes the synthesis and development of functionalised nanoparticles (NPs), which should form stable dispersion and act as efficient emulsifiers for subsurface oil and gas applications. These NPs have to be stable and function as emulsifiers at an elevated temperature and high salinity, aiming to increase oil recovery. Particle stabilised emulsions are very stable against phase separation. However, in order to recover the oil produced from a well, these emulsions have to be broken. Therefore a new demulsification technique was developed. All these findings are crucial for using NPs in every aspect of the oil extraction process, for instance as nanosensors, contrast agents or additives in drilling and injection fluids. In order to produce functional NPs, the surface of silica NPs was modified by grafting five different polymers via different methods in order to synthesise stable, aqueous dispersions of functionalised nanoparticles at reservoir condition. Four key criteria were identified from the experiments to produce NPs; Oligo 2-dimethylamino-ethyl-methacrylate grafted silica NPs (ODMEAMA-SiO2) were synthesised accordingly. ODMEAM-SiO2 had a hydrodynamic diameter of 65 nm and were stable in brine, up to 1.7 M American Petroleum Institute (API) brine at 65°C; these NPs also acted as efficient emulsifiers under the same condition, forming stable decane-in-brine emulsions with 75 vol% of decane; the droplet size of emulsions decreased with increasing molarities of NaCl and/or CaCl2 salts. The viscosity of particle stabilised (Pickering) emulsion behaved as a visco-elastic gel and can be lowered efficiently by additional water dilution to 1 Pa?s . The transport of various NPs through a high permeability water and oil saturated Bentheimer and Berea sandstone was studied by passing up to 500 Pore volume (PV) NPs dispersions through them. Seven different NPs were qualitatively compared with a surfactant polyoxyethylene nonylphenyl ether (ENP), with respect to the retention of NPs and enhanced oil recovery (EOR). The retention of NPs was 3.5 folds lower than ENP surfactant in high permeability core. The addition of 1 wt% ODMEAMA-SiO2 in water did improve the enhanced oil recovery (EOR) that is after initial water flood by 8.5 % from the high permeability core. For the lower permeability core, polystyrene NPs were found to emulsify oil in-situ by producing an emulsion, which allowed recovering extra 27.5% oil. A new demulsification approach was demonstrated. Hydrophobic silanised sand was used to pack filtration columns (SPC) and a particle stabilised oil-in-water (o/w) emulsion passed through. The effectiveness of hydrophobic SPC to break down o/w emulsion was subsequently studied by two different sand sizes and compared to traditional thermal, gravitational treatment. Demulsification was not observed by increasing the temperature to 65°C or centrifugation at 7500 rpm. Phase separation can be achieved by exploiting the difference in freezing points of internal and external phase of emulsions, or using the hydrophobic surface of SPC as wetting and coalescing medium. However, freezing which was time consuming and energy intensive, was not practical for large scale application. The SPC approach is efficient, fast, simple, flexible to use, with highest recovery of oil as 88 % and NPs as 93%.

Unsteady (time-varying) heat transfer is an important transport phenomenon that is found in many engineering and industrial applications. In such systems, generic spatiotemporal variations in the flow give rise to variations in the heat flux for a given fluid-solid temperature difference, which can be interpreted as spatiotemporal fluctuations of the instantaneous heat transfer coefficient. These variations can lead to unsteady and conjugate heat transfer, in which the exchanged heat flux arises from an interaction between the bulk fluid temperature and the temperature in the solid. Further, the non-linear coupling between the fluctuating temperature differences and the heat transfer coefficients can lead to an effect we refer to as augmentation, which quantitatively describes the ability of a particular arrangement to have a different time-mean heat flux from the product between the mean heat transfer coefficient and the mean temperature difference across the fluid. In this thesis we investigate unsteady conductive-convective heat transfer, and the resulting augmentative and conjugate effects. The overriding purpose is to propose a simple framework for the description of the effect of unsteadiness on the overall heat exchange performance, leading to the improved understanding and prediction of related processes. An analytical model is developed that describes the thermal interaction between the solid and the fluid domains with the use of a time-varying heat transfer coefficient, and assuming 1-D conductive heat transfer in the solid. It is found that the degree of augmentation can be defined in terms of key independent problem variables, including: a time-averaged Biot number, a dimensionless solid thickness (normalised by an unsteady thermal diffusion length), a heat transfer coefficient fluctuation intensity (amplitude normalised by the mean), and a heat capacity ratio between the fluid and solid domains. The model is used to produce regime maps that describe the range of conditions in which augmentation effects are exhibited. Such maps can be used in the design of improved heat exchangers or thermal insulation, for example through the novel selection of materials that can exploit these augmentation effects. Cases are considered for which the bulk fluid temperature is fixed, and for which the bulk fluid temperature is allowed to respond to the solid, both in thermally developing and fully developed flows. Generally the augmentation effect is found to be negative, reflecting a reduction in the heat exchange capability. However, regions of positive augmentation are uncovered in thermally developing convective flows, which has important implications for heat exchanger design. The approach is used to model two different thermodynamic cycles; gas springs and two-phase thermodynamic oscillator engines. Firstly, for the gas spring it is found that at low Peclet numbers the addition of an insulating layer exacerbates the thermal losses in the spring as it shifts the system away from the isothermal ideal operation. Conversely at high Peclet numbers thicker insulating layers reduces the loss as it shifts the system towards the adiabatic ideal. It is also found that there is an intermediate thickness of material thickness which maximises the loss in the gas spring, by up to 20 % of the nominal maximum loss for an isothermal cylinder lining. Secondly the heat transfer and resulting shuttle loss in the vapour space of a two-phase thermofluidic oscillator was studied. This model was compared to experimental data from a working test bed and resulted in a substantial improvement in the calculation of the cycle efficiency of the engine. Detailed flow measurements were also conducted on a fluid film flowing down a heated incline, to investigate the effects of unsteady heat transfer in these flows. These wavy interfacial flows exhibit large and periodic fluctuations in heat transfer and the frequency and amplitude of the waves was controlled by a specially constructed flow preparation arrangement. To enable the temperature and heat flux measurements the heated incline consisted of a thin titanium foil. A novel measurement technique was developed (here, for the first time) to measure the film interface height (film thickness), film temperature and instantaneous heat flux through the heated surface. This was achieved with a combination of spatiotemporally resolved Laser Induced Florescence (LIF) measurements and Infra-red (IR) thermography. In the case of steady flow conditions (without forced waves) the formation of Marangoni driven rivulet structures are observed on the film surface. In the case of unsteady flow the formation of waves on the film surface result in visible mixing of the rivulet structures. The mixing and the unsteady motion of the waves give rise to a periodic fluctuation in the heat transfer coefficient, with fluctuation intensities of up to 35 % being recorded. The model predictions of the augmentation ratio for these problems are also compared to direct measurements from each case. Good agreement is observed with the experimental results for the global heat transfer trends. In both cases the augmentation ratio is negative, reflecting a reduction in time-averaged heat transfer. Finally, a backwards-facing step flow is also studied, for which a low magnitude of augmentation was observed (< 1 %), considerably lower than the augmentation measured in the thin film flows which were up to 10 %.

Model-based analysis of cellular metabolism can facilitate our understanding of intracellular kinetics and aid the improvement of cell growth and biological product manufacturing. In this thesis, a model-based kinetic study of cytosolic glucose metabolism is presented. Based on the Kyoto Encyclopedia of Genes and Genomes and the Braunschweig Enzyme Database, a metabolic map of cytosolic glucose metabolism including 30 metabolites and 36 reactions, which consists of glycolysis, glucogenesis, pentose-phosphate pathway and adjacent metabolic reactions, has been constructed. Kinetic modelling was performed according to this metabolic map and reported enzyme kinetic studies, considering regulation and/or inhibition by products, substrates or other metabolites. Parameters were estimated based on previous parameter information and metabolic flux analysis studies, as well as results from our own experiments. Simulation results for cell population kinetics, metabolite concentrations and reaction rates have shown good agreement with experimental data. Furthermore, in silico case studies including global sensitivity analysis, feeding lactate as a co-substrate and the regulation effect by fructose 2,6-bisphosphate were performed in order to find strategies to increase metabolic efficiency in Chinese hamster ovary cells in an attempt to provide a guide for process optimisation. In conclusion, our model provides a deep look into cytosolic glucose metabolism and the simulation results have suggested a suitable direction to increase the metabolic efficiency.

This thesis presents experimental studies relating to gas-liquid slug flows in horizontal and near-horizontal pipelines. In such flows, liquid-continuous regions (“slugs”) pass along the pipe separated by regions of stratified flow (“elongated bubbles”) (see Chapter 1). Gas may be entrained at the slug fronts and is subsequently discharged into the elongated bubble at the slug tail. The focus of the work described in this thesis is on this gas entrainment process. Specifically, the aim is to make objective measurements of the slug front gas entrainment rate. A review of the earlier work (see Chapter 2) showed a large diversity of results for slug front gas entrainment. This reflects the difficulty of doing objective experiments on this important parameter. In the work described here, two new techniques for determining gas entrainment rate were implemented and investigated, namely the three-way valve method and the bubble shrinkage method. All of the experiments described in this thesis were with air-water flows at near atmospheric pressure, though the techniques developed could be applied to other fluid pairs and to different pressures. The three-way valve method involves diverting a slug front to pass over a stratified liquid layer and to determine the gas pick-up rate at the slug front from the slug front propagation velocity. The experiments were carried out for a 32.8 mm pipe in the LOTUS facility (described in Chapter 3) and for a 78 mm pipe using the WASP facility (also described in Chapter 3). The experimental results are presented in Chapters 4 and 5 respectively and show that the gas entrainment rate per unit film width is similar for the two diameters and depends on the relative velocity between the slug front and the liquid film ahead of it. The results indicate entrainment rates which are within the range previously measured but which are above those calculated from the existing correlations. A new correlation for prediction of gas entrainment in slug flow in horizontal pipes was developed which adequately predicts previous gas entrainment work (repeated here using LOTUS facility). In the bubble shrinkage method, the aim is to measure the shrinkage rate (and hence the rate of loss of gas by entrainment) of an elongated bubble passing along a pipe in a liquid flow. Development work on this method is described in Chapter 6 and (though the test section lengths were not sufficient to measure shrinkage accurately), it could be deduced (from measurements of the slug front (bubble tail) velocity) that the results were consistent with the three-way valve experiments. The actual phenomena accompanying gas entrainment at the slug front in slug flow are extremely complex and this was demonstrated with high speed video photography using an Olympus i-SPEED 3 system (see Chapter 7). Depending on the actual conditions, the advancing slug front could be attached to or detached from the preceding liquid layer. There were significant differences in the phenomena observed depending on the nature of the preceding liquid layer (stratified flow, descending liquid film, and stationary liquid film).