The use of catalytic systems operating on waste products such as biogas offers a potentially attractive alternative for renewable and sustainable energy generation. To investigate the potential viability of such catalytic systems for operation on biogas, a detailed study of nickel-based catalysts for the reforming of simulated biogas (methane:carbon dioxide = 2) to synthesis gas has been undertaken. The influence of oxygen addition in varied concentrations to the simulated biogas mixture has been investigated with regards to catalyst activity, selectivity and stability. This influence has been studied over an extended temperature range from room temperature to 1000 °C. Additionally, the effect of H2S within the simulated biogas mixture on the catalyst activity, selectivity and stability has been studied. Also, the influence of ceria-doping of the nickel catalyst on catalytic behaviour has been investigated. Temperature programmed and conventional catalytic reaction measurements have been used to analyse the catalytic behaviour and long term stability of the catalyst system over a full range of reaction temperatures. Carbon deposits from the simulated biogas reforming were analysed using post-reaction temperature programmed oxidation to assess the extent and nature of carbon deposition. The addition of oxygen significantly increases catalyst activity and shows a variation in product selectivity with temperature. Increased catalyst stability through reduced carbon deposition and increased sulfur tolerance is also observed with oxygen addition. Doping of the nickel catalyst with ceria enhances the influence of oxygen, apart from at high oxygen levels where total oxidation of methane is prevalent. Catalyst regeneration from sulfur poisoning has also been shown through oxygen addition to the simulated biogas mixture and ceria-doping of the nickel catalyst. Fuel cell studies have shown the successful operation of solid oxide fuel cells on simulated biogas and the substantial improvements in electrical performance through addition of oxygen and increased temperature.

A combination of Temporal Analysis of Products, Temperature Programmed Reduction, and Density Functional theory techniques have been used to perform kinetic analysis on data from heterogeneous catalysis experiments. A new method of data filtering has been developed for Temporal Analysis of Products, and has been applied to a system of 4 Pt−Mo2C, and the current methodology has been expanded upon to calculate rate coefficients for the oxidation of CO to CO2 via the Boudard reaction. From the kinetic constants it appears that a phase change occurs in the material at approximately 200�C. The current theory for analysing Temperature Programmed Reduction has been applied in a new methodology which is able to perform the deconvolution of thermograms with high accuracy, while also calculating the kinetic parameters related to the reduction processes. This new methodology has been applied to a system of CeO2 calcined at 400, 500 and 600�C and the strengths and limitations of the methodology are explored. From the deconvolution procedure it was found that there are three distinct reduction processes occurring on the CeO2 and that a phase change occurs between 400 and 500�C. Finally Density Functional Theory combined with classical dynamics has been used to explore the mechanism of the hydrogenation of Levulinic Acid to gamma-Valerolactone over a CuZrO2 catalyst. It was found that the Levulinic Acid is more likely to hydrogenate then cyclise, and from using molecular dynamics simulations it was shown that the solvent H2O plays a very important role in the cyclisation of the hydrogenated intermediate.

The following thesis used chemometric software to examine data generated from differential analysis of complex mixtures. Three different chemometric projects were investigated along with the comparison of two different chemometric software packages. 1. Liquid chromatography linked with mass spectrometry (LC-MS) was used to analyse gelatin from different species of animals. Using Agilent Technologies MPP chemometric software to analyse the data it was possible to find peptide fragments that were specific to each species of gelatin. Identification of these peptides was very difficult due to the destructive nature of gelatin manufacture. The method developed in this thesis allowed identification of 21 unknown gelatin samples with 100% accuracy. 2. Whiskey samples that had been matured in either American or Spanish oak barrels, and sampled over 22 years were analysed by LC-MS, the data was analysed with Agilent’s MPP chemometric software and the differences between the two wood types evaluated. Out of the compounds discovered to differentiate the whiskey from the different wood types two were identified as Gallic and Ellagic acid. These two compounds could be used to determine the wood type, a particular year of whiskey, or years of maturation for a whiskey matured in a particular wood type. The data generated for Whiskey maturity was also analysed using Waters Progenesis software and a comparison of the discovered compounds drawn. This highlighted an issue with incorrect assignment of neutral masses by MPP software. The data extraction method used by Progenesis was also found to be much less labour intensive than data extraction with MPP. 3. MPP was used to compare LC-MS data generated from the blood plasma of people suffering with multiple sclerosis with an age and gender matched control group. This was an un-targeted approach which led to the discovery of two compounds, Sphingosine and Dihydrosphingosine that were found to be lower in the blood of people suffering from multiple sclerosis. These compounds were searched in a larger sample set and found to follow the same trend of being lower in the disease group. It may be possible to use the concentration of these compounds in the blood as a marker of the disease.

This research project focused on a range of gel forming polysaccharides, including sodium alginate pectin and gellan gum. All of these materials have ability to form a gel responding to different stimuli, such as pH and crosslinking ions. Their capability to undergo sol-gel transition in presence of mono or divalent cations can often occur in seconds making it particularly difficult to measure the gelation in real time. Therefore, the aim of the work presented in this thesis was to design a new technique that allows commercially available rheological equipment to monitor the gelation progress of these materials. The first part of study involved the design a new method to measure the gelation of alginate and pectin in situ on exposure to an external source of calcium ions. Direct mixing of alginate or low methoxy pectin with divalent cations such as Ca2+ generally produces heterogeneous gels that form almost instantaneously. Therefore, it is particularly difficult to measure the rheological properties of this gelation event due to the rapid gelation kinetics. In this study the gelation progress was measured on exposure to three different concentrations of CaCl2 and gel dissolution time was measured by removing the crosslinking Ca2+ from freshly formed alginate and pectin gels by exposure to calcium chelators. The modification of the rheometer to facilitate these measurements used a petri dish attached to the lower plate of the rheometer, into which a piece of filter paper submerged with calcium chloride solutions (50, 100 and 200 mM) was placed. On top of the filter paper dialysis membrane (MWCO 14000) was placed as a barrier to prevent the filter paper imbibing polysaccharide samples. Samples of alginate and pectin 4% w/w were loaded on to the membrane and small deformation oscillatory measurements of elastic modulus (G′) and viscous modulus (Gʺ) were taken in the linear viscoelastic region, to monitor the gelation as a function of time. Once the gelation was complete the filter paper was removed and replaced with filter paper immersed with calcium chelating agents (500 mM of EDTA and sodium citrate (Na citrate)) to degrade the gel in situ. The results demonstrated that this technique was suitable for analysing the external gelation of alginate and pectin with a sharp increase in G′ in the first three minutes which then plateaued over the remainder of the test. It was also shown that gel stiffness reduced to a greater extent on exposure to EDTA compared with Na citrate. This method is not only suitable for measuring rapid gelation kinetics on exposure to cross-linkers, but has potential applications in modelling the in situ gelation behaviour in simulated physiological environments. The second part of the study investigated using the method developed for the alginate and pectin gelation for the in situ gelation of gellan gum under simulated physiological conditions using different types of simulated body fluids, simulated wound fluid (SWF), artificial saliva (AS), artificial lacrimal fluid (LF) and artificial gastric fluid (GF), measuring the gelation of gellan gum solutions (0.25, 0.5, 0.75 and 1% w/w) in response to ionic crosslinking and acidic pH. The results showed that gellan made the stiffest gels with GF, followed by LF and SWF (which were of similar stiffness to each other) and the weakest gel was formed with AS. The results indicate that this method is not only of use to measure rapid gelation kinetics on external exposure to cross-linkers but could find application in designing bioresponsive delivery systems in the food, pharmaceutical and biomedical industries. The final section of this thesis focused on the design and proof of concept of a new device that was 3D printed using Acrylonitrile Butadiene Styrene polymers (ABS), termed a rheo-dissolution cell. This was investigated to overcome the limitations of the petri dish method used in the initial studies. The cell was designed to contain a reservoir capable of holding crosslinking solutions and dissolution media allow with sampling ports to be able evaluate rheology measurements of in situ gel forming systems while simultaneously measuring release of molecules loaded into the gel. On the top of the reservoir a retractable stainless steel mesh was used as the lower plate of the rheometer which allowed the polysaccharide samples to be in contact with the fluid in the reservoir during the gelation and gel dissolution. Proof of concept was determined using 1% w/w alginate solution loaded with 50 mg of methylene blue. Rheological measurements were performed with CaCl2 in the rheo-dissolution reservoir to initiate gelation. Once the gels were formed gel dissolution was initiated by replacing the CaCl2 with calcium chelating agents EDTA and Na citrate. During both of these processes samples from the reservoir were removed and analysed for methylene blue release. The results showed the device was capable of allowing the formation strong gels on exposure to CaCl2 and gel dissolution when the formed gels were exposed to the calcium chelators. It was also found that mesh opening size was an important factor in the final gel strength and subsequent gel dissolution time. The strongest gels were formed when the mesh had a large opening area and the chelating of calcium was faster with EDTA than Na citrate. Methylene blue was detected in the reservoir during both gelation and gel dissolution with gel strength appearing to be an important factor on the quantity released gels increased. This study indicated that the rheo-dissolution cell has the potential to be used as a model system for measuring rheological changes and release rate of loaded drugs in gel forming formulations simultaneously by a simple modification of a commercially available rheometer.

Bioethanol can be considered as one of the best replacements for petrol because of its positive impact on environment and many other advantages. Currently, bioethanol accounts for around 2% of the global road fuels and this is projected to increase to around 10% within the next few decades. Bioethanol is a very high water consuming product, with an average global water footprint of 2855 L H2O/L ethanol. A growing worldwide demand for bioethanol has raised concerns over the use of freshwater resources. This PhD project aimed to establish a marine fermentation strategy for bioethanol production where seawater replaced freshwater for the preparation of fermentation media in conjunction with use of marine yeast as a biological catalyst, and potentially utilising a marine biomass (i.e. seaweed) as a carbon source substrate. Yeasts that are present in marine environments have evolved to survive hostile environments. Therefore, yeast isolated from marine environments could have potentially interesting characteristics for industrial applications. Current methods for marine yeast isolation suffer several limitations as they usually encourage the growth of filamentous fungi and produce low number of yeast isolates. A new method was developed in this study, which included: a 3-cycle enrichment step followed by an isolation step and a confirmation step. By applying this method on 14 marine samples (collected in the UK, Egypt and the USA), a large number of marine yeast isolates was obtained without any bacterial or filamentous fungal contamination. Amongst these isolates, 116 marine yeast isolates were evaluated for their capacity for utilising monomeric fermentable sugars (glucose, xylose, mannitol and galactose) using a seawaterbased media, this assessment of sugar utilisation was performed in a phenotypic microarray assay. Following determination of sugar utilisation, 21 isolates that representing the best sugar utilisers were further characterised using YT-plates (BioLog) and identified by DNA sequencing using ITS and D1/D2 primers. The identified isolates belonged to 8 species: Saccharomyces cerevisiae (5 strains), Candida tropicalis (4 strains), Candida viswanathii (4 strains), Wickerhamomyces anomalus (3 strains), Candida glabrata (2 strain), Pichia kudriavzevii (1 strain), Issatchenkia orientalis (1 strain) and Candida albicans (1 strain). Out of the 21 identified yeasts, 9 strains representing different species were screened for ethanol production using YPD media containing 6% (w/v) glucose and prepared by freshwater (ROW) and seawater (SW). Results revealed that 3 marine S. cerevisiae strains (S65, S71, and S118) had the best fermentation rates when using SW media. These yeasts were therefore taken forwarded for investigation into their growth performance under high concentrations of glucose and seawater salts (the components of synthetic seawater). Results determined that these marine strains were significantly more tolerant when compared with a reference terrestrial S. cerevisiae strain. Fermentation experiments using YPD media containing 6% glucose were prepared using synthetic seawater (SSW), 2x SSW and different sodium chloride (NaCl) concentrations (3, 6 and 9%) and results confirmed that the marine strain S65 was a highly halotolerant and osmotolerant yeast with high fermentative capacity. In a batch fermentation using 15 L bioreactors, strain S65 produced 73 g/L ethanol from 165 g/L of glucose within 20 h of fermentation, with ethanol productivity of approximately 4 g/L/h. In a batch fermentation, using sugarcane molasses (about 14% sugar) prepared in SW, strain S65 produced 52.23 g/L of ethanol after 48 h. According to literature, determination of sugars in samples which contain chloride salts was inaccurate when applying an existing HPLC method because chloride ions and sugars (especially glucose and sucrose) elute at a similar retention time. In this study seawater - which contains high concentration of NaCl (about 2.8%) - was used for preparing the fermentation media and therefore, developing a new method for sugar determination was necessary. Subsequently, an accurate and reliable HPLC method for the simultaneous quantification of chloride salts, sugars, organic acids and alcohols was developed. The method was validated for the accurate quantification of NaCl and successfully applied on fermentation samples as well as variety of food samples from retail market. The results obtained in this study highlighted the potential for using marine yeasts and the suitability of seawater-based media for the production of bioethanol. They also provide a new strategy for increasing the efficiency of bioethanol production at the industrial level with positive impact on food and freshwater scarcity issues.

The dispersion strengthening is a process that strengthens the material's matrix with use of the smallest precipitates. The most power comes from the character of the nanostructures, their chemical compositions, crystallographic structures, sizes, shapes and interfaces between matrix and precipitates. Through analytical methods it is possible to study and achieve the optimal mechanical properties of elements produced from high-manganese steels with dispersive nanoparticles such as carbides or carbo-nitrides. So far the most effective research methods are transmission electron microscopy and spectroscopy with use of multiple detectors such as Dual Electron Energy Loss Spectrometer (DualEELS), Energy Dispersion X-ray detector, (EDX) or Gatan Imaging Filter (GIF). The DualEELS, which is mostly developed during this thesis, is a technique which results in spectrum imaging of all elements presented in the analyzed area. The material studied during this Ph.D. is a high-manganese steel with vanadium and niobium carbides or carbo-nitrides with various sizes from few to dozen of nanometers, but the average is less than 20nm. The main goal of this Ph.D. is to advance the current available methods of nano-analysis using DualEELS of the smallest precipitates embedded in the matrix supported by improved and optimized sample preparation method with Focused ion Beam (FIB) lamella. The advancement is made in several fields including development of acquisition conditions, development of sample preparation technique using low voltages at FIB, and development and adaptation of the novel post-processing routines of the acquired data using Gatan DualEELS QuantumER post-column detector. The post-processing routine involved quantitative and qualitative analysis of precipitates, which required new values of partial cross-sections and mean free paths of inelastic scattering events estimated and calculated based on experimental (standards) approach. The results consist of fully quantified precipitates (V,Ti)(N,C) and ((Nb,Ti)C) supported by chemical profiles, comparison discussion between specimen, with a pseudo-3D reconstruction of spectrum imaging of these precipitates, which means that all elements have individually calculated thicknesses. The results gave a glimpse into the nucleation of the smallest precipitates, unexpectedly different than in most literature, showing that in this case there is no core-shell structure in mixed transition metal carbides. The Ti, which is not an intentional part of the alloy, acts as a nucleation sites, but is not built over core for the V or Nb mixed precipitates. These results are shown by four examples of V-steel and three of Nb-steel. They are presented as spectrum imaging signals, separated from matrix, with pseudo 3D representation and quantified in absolute manner with the accuracy down to a few atoms.

For many years the Plastic Deformation of bcc metal crystals has formed the subject of numerous investigations comprising a wide range of experimental techniques. One of the more recent and novel of these techniques is Synchrotron White Radiation Topography. This is well suited for examination of relatively large areas of comparatively thick crystals, without the need for undesirably long exposure times (as encountered, for example, in conventional topography), typical values being of the order of seconds, making dynamic, in situ experiments feasible. In this study, Synchrotron White Radiation Topography was used to make in situ, dynamic observation of the evolution of slip bands in single crystals of Fe 3.5 wt % Si (of rectangular cross-section) with two different surface orientations under uniaxial tensile stress in the [Oil] direction. Both types of crystal were oriented for double slip, in one the primary Burgers vectors lying in the crystal surface, and in the other the primary Burgers vectors lying at an angle of 35° 16' with the surface. Slip morphology in particular, was found to be a sensitive function of surface orientation. The studies reported in this thesis form a continuation of the work reported in Miltat and Bowen ([32]), and demonstrate the usefulness of the technique in studies of this nature. Important information on the early stages of deformation and the progress of slip was obtained. In Chapter 1 a brief review of the type of work that has already been conducted on bcc metals is presented, with particular reference to Iron and its alloys with Silicon. Chapter 2 presents a description of the apparatus used throughout the work, including a detailed description of synchrotron X-ray sources, and the sophisticated direct imaging equipment essential for dynamic experiments. The basic experimental approach adopted is outlined in Chapter 3. Chapters 4 and 5 comprise a brief review of contrast theory in X-ray topography, and how this theory can be applied to interpret topographs. Experimental results are presented in Chapter 6, and these results are discussed in detail in Chapter 7. A brief description of the effect of stress on the magnetic domain configurations in the specimens is given in Appendix I. Details of a calculation conducted with J. Miltat ([225]) on the projective geometries of white beam topographs are presented in Appendix II. Results of detailed calculation of integrated intensities expected on the topographs are given in Appendix III.

The work described in this thesis is concerned with laser kinetic and spectroscopic investigations of two distinct types of charge-separation process following electronic excitation, namely, (i) the kinetics of quenching by intermolecular electron-transfer and (ii) the development of (intramolecular) excited state dipoles as evinced by solvatochromic effects on both fluorescence and triplet-triplet absorption spectra. The kinetic studies refer to several systems, i.e. the fluorescence quenching of 9,10-dicyanoanthracene and 2-aminoanthracene in both polar and non-polar solvents and the triplet quenching of xanthone and thioxanthone, and also singlet thioxanthone, in MeCH/H20 mixtures. Correlation of the logarithm of the quenching rate constant (k23) with the free energy of the electron-transfer (ΔGo23) was attempted in terms of current models for electron transfer due to Marcus, Weller, Polanyi and others, sufficiently wider ranges in ΔGo23 being utilised to effect reasonable discrimination. In the case of 9,10-dicyanoanthracene, fluorescence quenching was effected both by donors (inorganic anions in Me0H/H20 and alkylmetals in cyclohexane) and organic acceptors in MeOH (Chapter 3), while quenching of 2-aminoanthracene was by organic acceptors in MeOH (Chapter 4). In general the Polanyi treatment gave better agreement, although this could not always be distinguished from the Rehm-Weller model. The quenching rates both of the singlet and triplet states of thioxanthone by inorganic anions were determined, enabling a comparison of their reactivity, as were the quenching rates of triplet xanthone, all in MeCN-H20 mixture (3:2 v/v), (Chapter 5). Triplet thioxanthone is quenched 102-fold more slowly by SCN- and Br- ions than singlet excited thioxanthone, which may be understood in terms of a higher value for ΔGo23 for the same acceptor in its singlet as cotrpared with its triplet state. The triplet quenching rates were correlated more satisfactorily with ΔGo23 by the Polanyi treatment. Solvatochromism was examined in two systems (Chapter 6) namely, the fluorescence of 2-aminoanthracene and N,N-dimethyl-2-aminoanthracene, comparison of which confirms (a) that the former is affected by solvent-donor hydrogen-bonding in hydroxylic solvents and (b) that Bilot-Kawski and related expressions provide a more specific analysis of solvatochromic affects than the Dimroth and related solvent parameters. The red-shift in the fluorescence maxima of these fluorophores with increasing solvent polarity was interpreted on the basis of increases in the dipole moment of the state over that of the Sostate. While the fluorescence maxima of xanthone and thioxanthone show substantial red-shifts with increasing polarity, as measured by the polarisation function of Bilot and Kawski, indicating an increase in dipole moment on excitation, the triplet-triplet absorption transient spectra of xanthone, thioxanthone and li-methylacridone are strongly blue-shifted, indicating a decrease in dipole moment as estimated by the Suppan expression.

This thesis describes the use of high-field n.m.r. spectroscopy, in part combined with stable isotope labelling, to study the solution chemistry of nitrogen mustard (2-chloro-(N-2-chloroethyl)-N-methylethanamine). Reactions with a range of nucleophiles were monitored by ¹H n.m.r. spectroscopy which demonstrated the generation of N-2-chloroethyl-N-methylaziridinium chloride from nitrogen mustard and step-wise substitution of nitrogen mustard except where polymerisation or hydrolysis occurred. The ¹H n.m.r. spectrum of the N-2-chloroethyl-N-methyl- aziridinium ion was resolved and fully assigned. The intermediacy of this species in reactions of nitrogen mustard is implied by experiments in which identical products are derived from a given nucleophile when added to either the aziridinium ion or the parent nitrogen mustard. Intermediacy of two successive aziridinium ions in alkylation of nucleophiles by nitrogen mustard was confirmed by examination of the 13c label distribution in products arising from alkylation of [2,2'-13c]-2-chloro-(N-2-chloro- ethyl)-N-methylethanamine. Applying a consideration of the stereochemistry of ring closure to N-methylpiperazine arising from alkylation of ammonia demonstrated that the observed 13c label distribution could only arise if aziridinium ion formation was irreversible. The isotope effect on ring opening of the aziridinium ion was measured under a range of reaction conditions for several different nucleophiles. Observation of the reaction between nitrogen mustard and methionine was simplified by the use of (S)-[13cH3]-methionine to demonstrate rapid formation of sulphonium salts and a slow breakdown to homocysteine and 2-methylthio-N-[2-(methylthio)ethyl]-N-methylethanamine. The synthesis of [2,2'-¹3C]-2-chloro-(N-2-chloro- ethyl)-N-methylanamine is described and a general synthesis of isotopically enriched nitrogen mustards is suggested based on this route. Efficient syntheses of (S)-[¹3CH₃]- methionine, (S)-[C²H₃]- methionine, (S) -ɑ - ²H-alanine and (S0 - (1-¹3C] - leucine are also described.

The hydrothermal synthesis of complex oxides of ruthenium and iridium with potential application as oxygen evolution reaction catalysts in polymer electrolyte membrane fuel cells is reported. The materials M0.15Ru0.85O2, where M = Zn, Mg, Ni, Co or Cu, have been synthesised from peroxide reagents and potassium perruthenate. Structural refinement against powder neutron diffraction data shows these materials adopt the rutile structure with space group P42/mnm with the metals substituting ruthenium and no evidence of oxide vacancies. X-ray absorption near-edge structure spectra recorded at the Ru K-edge show that to compensate for the inclusion of these metals, the ruthenium is oxidised above +4. New oxides based on (Ca0.59Na0.27)2Ir2O6·0.66H2O were produced with substitutions made on both the A and B-site. All materials were shown to adopt the pyrochlore structure with space group Fd m. The level of B-site substitution was found to be dependent on the substituent element (Sb, Ru, Rh, Mn or Zr), with maximum substitution levels ranging from 30-100 %. The zirconium substituted material, (Ca0.58Na0.32Zr0.12)2(Ir0.56Zr0.44)2O6·0.97H2O, shows significant deviation from the average structure at the local scale. The synthesis of the pure iridium material was further investigated and it was found both the A-site composition and particle size could be controlled. Treatment in concentrated H2SO4 at elevated temperature yielded materials with vacant A-sites. The hydrothermal synthesis of a number of other mixed metal oxides is reported. These include the perovskites Na(Ta1-xMx)O3, Na(Nb1-xIrx)O3and SrRuO3, where M = Ir or Ru, and x < 0.15, the hexagonal perovskite 4H-BaRuO3, Sr2.85Ir3O11 a material with a KSbO3-type structure and a barium iridate with an unknown structure. In electrochemical tests, performed in membrane electrode assemblies, all materials outperform the benchmark materials, iridium tantalum oxide and ruthenium iridium oxide under acidic conditions. The substituted rutile materials are highly active, but not as durable or selective towards the oxygen evolution reaction as the iridate materials. In situ studies of catalyst layers using X-ray absorption fine structure spectroscopy at the Ir LIII, Ru K, Rh K and Sb K-edges show that both iridium and ruthenium participate in redox chemistry at oxygen evolution conditions, however antimony and rhodium are redox inactive.