Strategies to combat climate change focus on every industry and has led to government policies to reduce electricity generation through coal combustion. Switching to biomass provides an opportunity to use infrastructure constructed for coal combustion with carbon neutral fuels; however, the process of grinding biomass pellets as fuel in pulverised fuel combustion is not well known. 1% of energy generated at a power plant is utilised to achieve the required size for the fuel. Improvements in the understanding of biomass pellet milling could lead to optimisation of operating conditions and minimisation of energy consumption. The process could aid generators determine appropriate fuels and costs for each; this represents a potential opportunity to elongate the life of current power stations, which is more cost effective than construction of new biomass specific plants. This research has developed a population balance equation (PBE) model simulation to predict the output of biomass pellet grinding for Lopulco E1.6 mill and a Retsch PM100 planetary ball mill; this has never been published in literature. It has proven it can predict the output particle size distribution of a Lopulco E1.6 mill, a scale model of an industrial mill, for biomass pellet PSD’s. It has shown that the simulation parameters can be based on axial and flexure deformation testing results, and that it can predict the PSD to within an average 88% accuracy against blind test. A novel technique in evaluating a PSD has been achieved using an overlapping coefficient, a measure better suited to PSD analysis than conventional model validation techniques. The PBE simulation has also shown that back calculating parameters can separate mill and material contributions when utilising a popularly used selection function and a breakage function developed in this research based on the Rosin-Rammler equation. This has been shown for the Lopulco mill and a lab scale planetary ball mill for axial and flexure deformation tests respectively. The research shows that emphasis should be placed on understanding classifier dynamics due to unexpected behaviour in the Lopulco mill experiments. Further conclusions show that energy consumption can be related to axial deformation energy that can be explained by the action of a Lopulco mill’s application of compressive force on and the orientation of pellets against the rollers.

The flourishing of oil palm industry has always been regarded as a double-edged sword. While it has significantly contributed to the economic growth, it is, nonetheless, disputably unsustainable as it is a land-intensive industry and causing disposal problems by leaving behind massive waste. To strengthening the industry’s competitive advantage and offsetting its drawbacks, this thesis presents a forward-looking framework – Biomass Supply Value Chain (BSVC)– to put emphasis on the value creation for the biomass industry. It aims to enhance the current biomass supply chain by harnessing the emerging technological advancement of artificial intelligence (AI), as well as by incorporating game theory to examine the strategic arrangement of the industry players. The proposed framework is capable of optimising the procurement process in the supply chain management: first, by identifying biomass properties for optimum biomass utilisation through the developed Biomass Characteristic Index (BCI); second, by applying AI into supply chain-related tasks for aiding better decision-making and problem-solving; and third, by adopting game theory in analysing strategic options, and providing appropriate strategies to minimise uncertainty and risk in procurement process. The “value” as suggested in the BSVC does not merely refer to a narrow economic sense, but is an all-encompassing value concerning non-monetary utility values, including sustainability, environmental preservation and the appreciation of the biomass industry.

PEDOT:PSS was investigated, using the dopants TWEEN 80 and MEK. The mixture was applied as a thin film on a PET substrate using three techniques, spincoating, dipcoating and spraycoating, with an aim to produce a bulk manufacturing conductive material. The dopants also improved the film forming of PEDOT:PSS. There was a problem with adhesion and durability of the film to the substrate. Several different materials were investigated to solve this problem. The adhesion problem was solved by adding a layer of methyl cellulose between the substrate and the PEDOT:PSS layers which acted as an adhesion promotor. One of the aims of this project was to determine a bulk manufacturing method which is viable for PEDOT:PSS. Three manufacturing techniques were investigated to see how this affected the film quality, film conductivity, thickness, orientation, and durability. Spincoating gave thinner films with a final thickness of 1- 2 µm and was more conductive than films manufactured using dipcoating or spraycoating. Spincoated films made using the dopants enhanced the bulk conductivity of the starting material by two orders of magnitude from 1494 Ωcm for the 100 % PEDOT:PSS dispersion used as a starting material, to 25 Ωcm for the doped 97.22 % PEDOT:PSS. The dipcoated and spraycoated samples were enhanced by three orders of magnitude, although, overall the spincoated samples were the most conductive. The enhanced 95 % to 98 % PEDOT:PSS dispersion with additives TWEEN 80 and MEK samples, remained more conductive than the starting material even after 62 weeks of storage under air. It was found that storage under air caused an increase in resistivity over the stored time period in doped PEDOT:PSS and 100% PEDOT:PSS films. High voltage studies up to 50V proved the material withstands repeated high voltage application over a period of 62 weeks. The mechanism of charge transport in the 97 % and 98 % PEDOT:PSS samples was found, using UV, to be due to the formation of polarons. Polaron charge carriers were formed when the polymer became ionised, lost an electron, and formed a positive charge on the polymer chain. In order to stabilise this the PEDOT molecule changes shape from the aromatic to the quinoid conformation. The most conductive films were found to be predominantly in the quinoid form whereas the less conductive films were mainly aromatic.

The challenges and specialised equipment associated with supercritical electrochemistry means standard reference electrodes (such as the saturated calomel electrode) cannot be used. The aim of the thesis is the investigation of a range of metallocenes as model redox systems against a Pt pseudo reference electrode in supercritical fluids. This work was then extended to the development of a new high pressure reactor. Initially, a range of metallocenes were investigated in liquid analogues of the supercritical fluids (acetonitrile and dichloromethane) to investigate their suitability. Cyclic voltammetry performed at both micro and macro electrodes were used to examine the behaviour of each individual redox couple. Electrochemistry of the metallocenes were then evaluated in supercritical fluids (supercritical carbon dioxide with acetonitrile and supercritical difluoromethane) for investigation as model redox systems. The diffusion coefficients have been determined at both micro and macro electrodes for both supercritical fluids. The implementation of baffled micro and macro electrodes has shown that the intrinsic convection (at the electrode surface) within supercritical fluids can be dampened. The diffusion of metallocenes in nanoporous aluminium oxide membranes (13 – 55 nm diameter cylindrical pores), in both supercritical fluids has also been investigated. This work was then extended to the development of a new high pressure plastic reactor leading to the first, successful, supercritical fluid electrodeposition of bismuth in the plastic reactor.

This report presents architectures, designs and chemistries for novel static soluble lead acid batteries, with the objective of producing a lightweight lead acid battery for improved specific energy. The demands for lightweight lead-acid batteries come from an expanding hybrid electric vehicle market demanding improved battery specific energy. There are several avenues for improving battery specific energy; the main two are improved active material utilisation efficiency and grid weight reduction. Both of these have been focuses of this project. Two approaches have been taken in this project, the first is focussed on the electrode design. Design modifications have been achieved by using novel grid materials to reduce weight and novel electrode designs to improve active material utilisation. Battery electrodes were built from titanium and the active material was applied as a thin film of lead. Characterisation of lead coatings on several material geometries under different plating regimes was conducted. A novel thin-film active material battery was designed, built and tested satisfactorily to industrial standards. The second battery system being investigated has the active materials solvated in the methanesulphonic acid electrolyte during the discharged state. Due to the high solubility of lead in this Pb-CH3SO3H electrolyte, lead-acid batteries with this chemistry have a theoretical specific energy of 35.7 Ah l-1. This compares favourably with the specific energy for a conventional spiral wound VRLA battery at 44.4 Ah l-1. These soluble lead acid batteries operate by a mechanism whereby cycling is stripping and plating lead and lead dioxide onto the electrodes. Active material utilisation in this type of lead-acid battery is not limited in the same way as conventional lead-acid batteries, as the discharge product is not electrically insulating, as is lead sulphate. The operation mechanism was improved by using additives in the electrolyte to maintain a quality deposit and preserve charge efficiency, voltage efficiency and active mass utilisation. In addition, the use of a separator membrane and novel carbon-polymer electrodes improved battery performance further. The behaviour of a static soluble lead acid battery during cycling with and without additives and a cell membrane is characterised and the results are used to develop a 6 V battery. The results of the 6 V battery cycling under HEV simulated cycling are presented and discussed.

Chalcogenide glasses, especially sulphide glasses, are becoming more and more important for the fabrication of optoelectronic devices in part because of the high nonlinearity, strong photosensitivity and several other unique properties they have. Chalcogenide glasses are normally fabricated by a conventional melt-quenching method. The glasses are then further processed to form, for example, thin films, optical fibre and optoelectronic devices. /°C. The purity of germanium sulphide bulk glass bas been determined by a glow discharge mass spectrometry (GDMS) technique and an exceptionally low level of transition metal impurities in this glass have been achieved.

Multimetallic molecular cluster compounds have been synthesised and characterised. They have been used as precursors for the generation, by heating under vacuum, of nanoparticles supported within the pores of mesoporous silica. By following their activation using infrared spectroscopy, it has been revealed how the temperature of thermolysis determines the nature of the active site. Through spectroscopic investigations of the active sites, the effect of altering the structure and stoichiometry on the surface metal sites has been elucidated. It has been shown how the inclusion of an oxophilic main group element in the precursor both improves the site isolation of the active sites and affects the oxidation states of the other metals present in the catalyst. The inclusion of an oxophile changes the nature of the bonding between the nanoparticle and the surface and presents different metal atoms at the nanoparticle surface, altering its catalytic activity. The selection of oxophile is crucial to the activity of the catalyst, since it is possible for it to form a key part of the active site, either purely as a coordination site or indeed as part of the redox system. The use of a molecular cluster precursor greatly enhances this synergistic effect, by ensuring the different metal atoms are chemically bound throughout catalyst preparation, activation and use.

This experimental study examined the development of a lightweight aluminium-air cell. The novelty of this study was the characterisation of the behaviour of the lightweight aluminium-air cell, depending on the choice of aluminium anode and air-cathode. Development of the prototype aluminium-air cell involved three areas of study. For the first two high purity aluminium alloys, Al/0.5 Mg/0.07 Sn and Al/0.4 Mg/0.07 Sn/0.05 Ga, were evaluated as anodes in a half-cell in 4 mol dm-3 NaOH at 22 °C and 60 °C and compared against 99.999 %wt aluminium. Alloys were pre-treated by solution heat treating in a furnace at 600 °C for 8 hours followed by a water quench. Corrosion rates were quantified at open-circuit and under galvanostatic discharge via a hydrogen collection method. For the second method of study, the electrochemistry of a LaCaCo3/LaCaMnO3 air-electrode, known as KTH, supplied by a project collaborator, was compared against seven commercial gas diffusion electrodes. The catalysts on the commercial electrodes include Pt, MnOx, Ag2O and Co-based. Air-electrodes were compared structurally using scanning electron microscopy, mercury intrusion porosimetry and pycnometry. The KTH electrode outperformed the others with a limiting current density for oxygen reduction of −463 mA cm-2 at −0.49 V vs. Hg/HgO. In the final area of study three prototype aluminium-air cells were investigated with the third one being selected as the final design. Cell characterisation involved measurement of electrode potentials and cell temperature during variable loading and galvanostatic discharge experiments, and assessing their inter-relationship. The best performing prototype cell with a solution heat treated Al/Mg/Sn anode and KTH air-electrode had a peak power density of 174 mW cm-2 at 208 mA cm−2. Under galvanostatic discharge at 100 mA cm-2 over an hour duration, this cell had a specific power capability of 62 W kg-1 and a specific energy of 66 W h kg-1.

Today fuel cells are far from being common place in the commercial market, primarily due to their high cost. The cost of such a system is largely determined by the platinum based catalysts used at both the anode and cathode of the fuel cell. If a non-noble fuel cell electrocatalyst could be used at either of these electrodes, the cost of a fuel cell system would be drastically reduced. Highthroughput physical vapour deposition and the modification of single crystal surfaces, has been used to synthesise candidate non-noble electrocatalysts which were then screened to determine their activity. Amorphous tungsten carbide thin films were shown to be catalytically active towards both the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). The constituent elements were seen to be less active than the alloys. These results are consistent with the literature where it has also been seen that WC is active, with W2C showing poorer activity.1,2 The trend in current density with respect to alloy composition confirms the results in the literature, with the highest activity seen at compositions corresponding to the WC phase, and a local minima in activity seen at compositions corresponding to the W2C phase. Metastable and amorphous intertransition metal alloys of WCu are shown to catalyse both the HER and the HOR. The constituent metals again exhibit poor activity. The results are consistent with ab initio calculations predicting HER activity for Cu overlayers on W, with the detected changes of the density of states (DOS) at the Fermi level associated with alloy formation.3 Two maxima in the HER activity are observed as a function of composition. This activity is associated with a metastable phase at W20Cu80 and a second at W50Cu50. The alloy at 50 at% also shows a maximum in the HOR activity, whereas the phase at W20Cu80 is not HOR active. The W20Cu80 phase is found to beoxygen covered at the HOR potential, explaining its inactivity. These results highlight the potentials of developing non-noble metal alloy catalysts for hydrogen fuel cells.

Spoilage of beer by lactic acid bacteria (Lactobacillus spp., Pediococcus spp.) has considerable economic significance. Compounds derived from the hop (Humulus lupulus) possess antibacterial activity but their role in prevention of beer spoilage has been disputed. Prior to the present study, the mechanism by which such compounds inhibited growth of beer-spoilage lactic acid bacteria was unknown. A range of hop compounds (colupulone, (-)-humulone, (-)-cohumulone) and hop-derived compounds (trans-isohumulone, trans-isocohumulone, trans-humulinic acid, dehydrated humulinic acid) was prepared and analysed using several spectroscopic techniques (UV, IR spectrometry; mass spectroscopy; 1 H-NMR f 13 C-NMR spectroscopy). The ability of these weak acids to ionise in solution was studied. The lack of agreement between pKa values measured using potentiometric, conductimetric, spectroscopic and solubility methods suggests that, in aqueous solution, the compounds formed covalent hydrates. Antibacterial activity of the compounds against Lactobacillus brevis IFO 3960 was pH-dependent: the undissociated form of each compound was the active antibacterial moiety and the ionised form had little activity. The antibacterial activity of the undissociated forms of each of the compounds was similar. In the case of the undissociated form of trans-isohumulone, 0.1-0.4ptM was sufficient to inhibit growth of Lact.brevis IFO 3960 in a modified version of de Man Rogosa Sharpe medium over the pH range 4.0-7.0. Trans-isohumulone acted as an ionophore of the mobile-carrier type. In lactic acid bacteria, H + was exchanged for Mn 2+ in an electroneutral process that required the presence of a second monovalent cation (e.grK + , Na + ).