The recovery of metals from secondary resources is increasing to alleviate supply risks associated with primary sources. Thermal plasma is widely used for platinum group metal recovery from automotive catalysts, but the mixing of various catalyst types makes their processing difficult. It was found that it was possible to separate silicon carbide based catalysts from cordierite based catalysts by a combination of magnetic and electrostatic separation processes resulting in a cordierite fraction of over 98 % purity, which would result in a more consistent feed material to the plasma process enhancing metal recovery. The flexibility of plasma means that the operational conditions in the furnace can be controlled to suit the chemistry of less noble metals such as rhenium and drive gas phase reactions. The technology was used to recover platinum and rhenium from spent petrochemical catalysts via a novel pyrometallurgical process with over 98 % recovery efficiencies of both metals. The plasma process produces a large amount of slag as a by-product which can be used in higher value applications to avoid waste and improve business models. Plasma derived slag was shown to be an effective, low carbon cement replacement which can potentially obtain a market value of £50/tonne.

The process of sheet metal forming is commonly used to create 3-D surfaces in, e.g., aircrafts and automobiles. Stamping is one of most common sheet metal forming processes but traditional forming processes which have been developed for mass production are inflexible and expensive, and economically unsuitable for small-scale production. More appropriate for small-batch and prototype production are flexible forming methods such as multi-point forming (MPF) which have been developed in recent years. A pair of opposed reconfigurable tools containing pin matrices could replace traditional solid stamping tools. Based on this technique, the construction of sheet metal forming tools becomes flexible and fast. Springback, caused by elastic recovery and release of residual stress, is an unavoidable issue in all sheet metal forming and significantly affects the geometrical precision of the products. Springback is a defect, and if it is beyond permissible tolerance it will adversely affect the assembly process such as distortion of sub-assemblies and poor fit-up during welding. Estimation of springback remains an important and challenging issue for the sheet metal industry. Based on the ABAQUS software, 3-D finite element models were generated, with the required constraints and boundary conditions described and applied in the simulation. The process of multi-point forming and springback were simulated by combining explicit and implicit algorithms. The influence of some significant working parameters, such as radius of forming curvature, blank holder force and elastic cushion thickness on final product quality (springback, thickness variation and wrinkling) has been investigated.

Experimental results and analyses have shown that significant improvements in coal grindability (reductions in Relative Work Index) can be achieved by exposing coals to microwave radiation. Experimental data have indicated that low rank coals are highly responsive to microwave radiation, possibly due to their higher inherent moisture content. There is evidence to suggest that gaseous evolution (water vapour and volatile matter) and localised zones of differential expansion (arising for example from occluded mineral matter) in coal during heating give rise to crack formation and hence are the probable causes for the measured increase in coal grindability. The composition of the various coals treated by microwave radiation remained relatively unaltered and there was no significant change in coal calorific value or the proximate and ultimate analyses (dry, mineral matter free basis). Initial (laboratory-scale) microwave trials and pilot-scale testwork demonstrated an improvement in the grindability of various coals. However, the gross energy input for these tests were excessively high (220k WhIt) in comparison to that used mechanically for pulverised coal production (15-20kWhlt). Improvements in microwave cavity design and increased electric field strengths may increase the energy efficiency of the process; however, further work would be required. Additional studies were carried out to evaluate the potential use of microwave technology for coal desulphurisation. The results were encouraging and show that substantial improvements in pyrite separation can be achieved with some coals. Fundamental studies have shown that there is significant change in coal flowability following microwave exposure.

Highly conductive (3.0 - 5.0 x 10 \(^{-4}\) \( \Omega\) cm) and transparent (80 – 85% ) ITO films were successfully fabricated on glass and polymer substrates (PET, PEN and PC) by pulsed laser deposition at low temperatures (24 – 150 °C). The influence of deposition conditions on the structural and physical properties of ITO-coated glass substrates was studied. The samples were investigated using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD), the fourpoint probe and a spectrophotometer. Sol-gel derived ITO films dip-coated on glass substrates were also studied. The optimum film obtained at a firing temperature of 600 °C had a resistivity of 1.8 x 10 \(^{-2}\) \( \Omega\) cm, and optical transmittance of 80%. The electro-mechanical behaviour of ITO/polymer systems was investigated under uniaxial tension and controlled buckling in tension and compression. The resistance changes were monitored in situ. Cracking and buckling delamination failure modes were observed for all samples investigated at critical strains raging from 2.8 to 3.4%, and from 7.0 to 8.0%, respectively. The results showed that the dominant critical failure mode depends on the applied stress conditions. The ITO/PEN samples showed high flexibility; the samples were buckled in tension down to a 2.6 mm radius of curvature before cracks start to occur.

Analysis of fatigue samples sectioned from commercial 319 (Al-Si-Cu-Mg) alloy cylinder block castings showed that shrinkage pore networks and oxide films played an important role in fatigue failure. A reduced pressure technique was employed to study the relationship between porosity and oxide films. Links between oxide films and porosity were made and mechanisms for the inflation of films into porosity networks were established. Tensile tests performed on samples cast with and without filters showed that the ultimate tensile strengths of the filtered group had a Weibull modulus 2.4 times that of the unfiltered. Samples with abnormally low strengths were found to contain oxide film defects. These films had an approximately 5 times greater damaging effect on strength than that predicted by reduction in cross sectional area. The fracture strengths of these flawed samples were found to obey a linear elastic fracture mechanics model (LEFM). A LEFM crack growth model was particularly successful in predicting the life of fatigue samples that initiated at oxide films. Having crack-like geometry, and a minute crack tip radius, oxide films effectively acted as preformed cracks. Consequently there was an absence of crack nucleation time, explaining the correlation of predicted propagation life to fatigue life.

In the first of the metalforming operations considered, that of plane-strain side-pressing, the finite-element predicted deformation behaviour of 60-40 brass and 7075 aluminium alloy has been compared with experiment. Both visioplasticity and hardness studies have been performed. The macrohardness survey was found to be the most appropriate in validating the use of the finite-element technique. The numerical calculations of the local stress and strain distributions are then used with a number of previously published continuum fracture criteria to predict the fracture initiation sites. For certain of the successful criteria the level of deformation at fracture has also been predicted using critical values of fracture found experimentally from an axisymmetric tensile test. For the operation of plane-strain side-pressing, very good agreement with both the experimental fracture initiation site, and the level of deformation at fracture, is reported for the criterion of a critical value of generalised plastic strain at fracture, and the equivalent criterion of generalised plastic work. The second metalforming operation considered is simple upsetting. The fracture initiation behaviour of 60-40 brass has been examined for specimens of the four initial aspect ratios of 0.5, 1.0, 1.5 and 2.0. Again, the generalised plastic strain/work criterion has successfully predicted the experimental fracture initiation sites in all cases. However, satisfactory levels of deformation at fracture predictions have only been found for the two lower aspect ratio specimens. A small range of strip compression and tension operations on 60-40 brass compose the third type of metalforming operation considered in this thesis. Yet again the generalised plastic strain/work criterion has successfully predicted the fracture initiation site found experimentally but not the level of deformation at fracture. Finally, the axisymmetric extrusion of 60-40 brass and 7075 aluminium alloy is examined. For the brass using the generalised plastic strain/work criterion, good agreement with experiment has been found for both the fracture initiation site and level of deformation at fracture found experimentally. However, for the aluminium alloy only the correct fracture initiation site has been found. In summary, it appears that the fracture criterion of a critical value of generalised plastic strain/work has successfully predicted the fracture initiation site found experimentally in all the operations considered in this thesis but has been unable to consistently predict the correct level of deformation at fracture. These differences in the predicted and experimental level of deformation at fracture cannot be explained with reference to the finite-element calculated levels of hydrostatic stress. Further work is necessary to explain this difference.

Using supramolecular principles, we have been designing luminescent lanthanide complexes with a defined hairpin bis-interlacator in order to obtain luminescent probes able to recognise DNA. The complexes are comprised of Platinum(II) terpyridine, which acts as a DNA recognition site and is brought together with a "remote" luminescent lanthanide unit. All the synthetic approaches were based on the accessibility of the lanthanide-platinum complexes by the self-assembly of different components in a one pot reaction. Thus, we have been able to isolate a water soluble heterometallic complex based on thiophenal linkage named [LnPt\(_2\)]Cl\(_2\). The complex has a relatively weak lanthanide luminescence, which increases upon addition of DNA. Photophysical and DNA binding properties of the lanthanide-platinum complex were investigated by UV-vis absorption, luminescent studies and circular and linear dichroism. Oligonucleotides of twelve bases were also used to investigate the intercalation [LnPt\(_2\)]Cl\(_2\) and the mono-intercalator AATP used as control compound. Using bidimensional NMR techniques, we investigated the binding site for [LnPt\(_2\)]Cl\(_2\) and AATP upon interaction with Dickerson-Drew sequence. The sulphur lanthanide-platinum linkage in [LnPt\(_2\)]Cl\(_2\) was replaced with an acetylide one in order to introduce new photophysical features. Thus the self-assembly procedures based on DTPA-bis(amido-acetylide) and a platinum(II) terpyridine led us to isolate a new lanthanide-platinum complex named [LnC\(\equiv\)CPt\(_2\)] (CH\(_3\)SO\(_3\))\(_2\). The photophysical properties and the DNA binding properties toward interaction with CT-DNA were investigated. The complex named LnC\(\equiv\)CPt\(_2\)](CH\(_3\)S)\(_3\))\(_2\) exhibited a relatively strong lanthanide luminescence that increased upon addition of DNA. The bi-functional metal complex [EuLPt](PF\(_6\)) (where Pt=platinum-2,2':6'2"-terpyridine and L=assymmetric DTPA bisamide ligand with a thiopheno pendant arm and a quinoline moiety) was synthesised and the interaction of [EuLPt](PF\(_6\)) with CT-DNA was examined by luminescence spectroscopy, linear and circular dichroism studies and thermal denaturation studies. The [EuLPt](PF\(_6\)) retained the ability to increase its luminescence upon the addition of CT-DNA. The binding properties of the complexes were tested toward interaction with plasmid DNA by gel electrophoresis and properties such as the unwinding angle were measured. The bis-intercalators [LnPt\(_2\)]Cl\(_2\) and [LnC\(\equiv\)CPt\(_2\)](CH\(_3\)SO\(_3\))\(_2\) showed the ability to uncoil DNA almost as well as cisplatin and at low concentrations, while almost double the amount of mono-intercalators, such as [EuLPt](PF\(_6\)) is required to observe the same uncoiling effect.

Ti-5Al-5Mo-5V-3Cr (Ti-5553), a relatively new generation beta titanium alloy has the advantage of high strength. It is a current generation alloy used in landing gear. Currently, landing gear components are large scale and processed through forging, followed by complex heat treatments. HIPping (hot isostatic pressing) is an alternative way to process this alloy. In this project, work was carried out on investigating microstructures and mechanical properties of HIPped Ti-5553 alloy. During comparisons on fracture toughness of different types of specimens, specimens are first heat treated to a similar strength level. And fracture toughness values are calculated at the same strength level circumstance. Various microstructures are obtained through different heat treatments. Different microstructures can be achieved through specified treated temperature/ time and quenching methods. Results show that larger grain size and coarser intergranular lath-like grain boundary alpha can improve the fracture toughness. One shell-like microstructure is obtained through different heat treatment conditions. Mechanical test was carried out on this kind of microstructure and compared to normal beta annealed microstructures. To investigate the influence of microstructure on fracture toughness, techniques including optical microscope (OM), scanning electron microscope (SEM), and confocal laser scanning microscope have been used.

No description available.

The research outlined in this thesis is concerned with the environmental aspects of groundwater re-establishment as a consequence of surface mining. No principal effects which have been identified as being detrimental to the restored land area are as follows; i). The vertical and horizontal displacements of backfill materials following restoration, and ii). The pollution of groundwater from contact with weathered rockfill materials. The research into settlement has attempted to classify the types of movement which may occur within a backfill mass, in particular the differential movements which are of great importance to the stability of proposed structures or surface drainage. The field results from 10 opencast mine sites are presented, 3 of which were instrumented for detailed field investigations. It has been shown that backfill movements do not necessarily show similar trends under similar conditions, and reasons for this are proposed. A variety of instrumentation schemes have been devised to examine backfill displacements, both vertically and horizontally. Permeability testing has been conducted at different horizons the backfill mass in order to locate the zones of collapse settlement due to groundwater recovery. A critical review of the instrumentation utilised in the investigations is presented, with suggestions for improvement. Investigations into groundwater pollution have been devoted to examining the qualities of groundwater flowing into British surface mines and evaluating its likely reactions with fill materials. An insight into general groundwater pollution and treatment techniques is presented together with a critical analysis of their applicability, to British conditions. An investigation into water qualities in each of the six geographical regions of the opencast mining industry of Great Britain is detailed. Finally some suggestions for future research areas are indicated.