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A major challenge to any “solvent-based” bitumen extraction technology is the removal of suspended fine solids from the hydrocarbon medium (i.e. diluted bitumen). To address this problem, we examined how colloidal solids could be made to aggregate in a hydrocarbon medium and thus be separated by gravity settling. The model solids were micron-sized “bitumen-treated” silica particles; the oil phase was bitumen diluted in an organic solvent of variable aromatic content. On the macroscopic scale, the experiments involved quantifying the settling rates of the particles as the aromatic content of the solvent was varied. Our results showed the existence of an optimal (non-zero) aromatic content at which the solids settling rate was the highest. On the microscopic scale, adhesive forces between individual glass spheres were directly measured using the microcantilever technique (again in non-aqueous media). It was demonstrated that, in addition to being captured by asphaltene networks, the suspended solids could also homo-flocculate — and thus form aggregates and be separated — in an alkane-diluted bitumen environment. / Chemical Engineering

Content removed due to copyright restriction: Nash, W., Pinder, D.N., Hemar, Y., Singh, H. Dynamic light scattering investigation of sodium caseinate and xanthan mixtures (2002) International Journal of Biological Macromolecules, 30 (5), pp. 269-271. Pinder, D.N., Nash, W., Hemar, Y., Singh, H. Dynamic light scattering investigation of guar/dextran mixtures in aqueous solutions (2003) Food Hydrocolloids, 17 (4), pp. 463-468. / Dynamic light scattering has been used to investigate three different non ideal ternary polymer systems. The three systems investigated were sodium caseinate and xanthan aqueous solutions, guar and dextran aqueous solutions and dextran and pullulan aqueous solutions. All solutions have been investigated at a temperature of 25°C. Sodium caseinate and xanthan aqueous solutions with total polymer concentrations ranging from 0.01% w/w to 0.15% w/w and ratios of sodium caseinate of x = 1:3, 1:2, 2:1, and 3:l have been investigated. Guar and dextran aqueous solutions with total polymer concentrations ranging from 0.01% w/w to 0.06% w/w at a ratio of guar to dextran of 1:6 have been investigated. Dextran and pullulan aqueous solutions with total polymer concentrations ranging from 1% w/w to 10% w/w with ratios of dextran to pullulan of 1:3, 1:1, and 3:l have been investigated. The solution concentrations have been chosen to fall in the semi-dilute range, while still being miscible. Three different methods of analysis have been applied to resolve the field autocorrelations function into a sum of decaying exponentials; CONTIN, CONTIN multiq, and a Kohlrausch-Williams-Watts fit. These resulting decay rates have been interpreted using the theoretical method outlined by Sun and Wang. The CONTIN multiq method provided the best overall fit to the data. The Sun and Wang method has not provided results which are consistent with those reported elsewhere in the literature. Additional theoretical effort must be applied to interpret the results from dynamic light scattering on these novel non-ideal systems.

Master of Science in Biomedical Sciences / Department of Clinical Sciences / Jessica Meekins / Objectives- To determine the effect of oral robenacoxib on experimentally-induced anterior uveitis, and to evaluate the ability of robenacoxib to cross an intact blood-aqueous barrier. Animals- Twelve healthy adult domestic shorthair cats. Procedures- Cats in the treatment group (n=6) received oral robenacoxib (1.51 ± 0.36 mg/kg ) once daily beginning 1 day before experimental induction of uveitis by anterior chamber paracentesis (ACP) and continuing 1 day after paracentesis. Anterior chamber paracentesis was performed using a 30 g needle attached to a 1 mL syringe, and 100 µL of aqueous humor were aspirated over 3-5 seconds. Anterior chamber fluorophotometry was performed in both eyes of each cat immediately before ACP (time 0), and at 6, 24, and 48 hours after ACP. An independent t-test was used to compare percent fluorescein increase in treatment versus control cats at each time point. Values of p<0.05 were considered significant. Concentrations of robenacoxib in aqueous humor were measured using liquid chromatography and mass spectrometry. Results- There was no statistically significant difference between the ACP and control eye at time 0 (p=0.322). When comparing the percent fluorescein increase between treatment and control groups, there was no statistically significant difference at any time point (p>0.05). Robenacoxib was present in small but detectable levels in 5/6 cats in the treatment group. Conclusions and clinical relevance- Administration of oral robenacoxib did not significantly lessen experimentally-induced anterior uveitis in normal cats, as assessed by fluorophotometry. Low concentrations of aqueous humor robenacoxib were detectable in the majority of cats receiving the drug.

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Stress corrosion cracking of a 14 wt% Cr martensitic stainless steel, with commercial names PH-15Cr5Ni, FV520B or X4CrNiCuMo15-5, used for the manufacture of low pressure turbine blades, has been studied with the intention of gaining a better understanding of the processes involved, how they occur and why. Industrially this is very important as stress corrosion cracking is considered to be a delayed failure process, whereby microscopic cracks can potentially propagate through a metal undetected until catastrophic failure occurs. The aim of this work is to establish links between crack length and external factors, such as exposure time, in order to devise a method of dating stress corrosion cracks and therefore predicting their possible occurrence in-service.

Aqueous solubilities of twelve chlorinated benzenes were determined by two methods. In one method, the solutions in water were prepared by a vigorous stirring method followed by n-hexane extraction and GC-ECD analysis. In the second method, HPLC was used to prepare the saturated solutions. Experimental results were compared with the predictive values, the relative standard deviations are around 10%. Most of the chlorinated benzenes exhibit water induced transformations. The transformation products were either isomeric or with higher and lower numbers of chlorine substituents. The transformation phenomena can be explained by polarity, symmetry, reactivity of the chlorine atoms, and hydrophobic interactions. The mechanism of the transformation is governed by the radical mechanism.

Electrophoretic displays (EDPs) are an attractive low power technology for small to large area displays. Such display technology has seen a surge of research interest with the launch of successful e-readers in the market place, owing to their lower power consumption and paper-like quality. This work aims to look at the influence of shape on the electrophoretic mobility of particles for such devices. Crosslinked poly(methyl methacrylate) (PMMA) precursor particles with a narrow size distribution were produced by non aqueous dispersion polymerisation utilising a pump-feed method. To produce shape anisotropic particles an adapted version of the dynamic swelling method for polar media was chosen. Suitable monomers were screened by the use of Hansen solubility theory to find monomers which interact with PMMA but not the solvent. It was found that 2- hydroxyethyl methacrylate (HEMA) and N-hydroxyethyl acrylamide (HEAm) were two such suitable monomers, methyl methacrylate (MMA) was also used as a control series.It was found that cluster-like particle morphologies could be produced by the MMA system by the inclusion of small quantities of crosslinking monomer. This was due to precipitation of higher molecular weight polymer segments to the seed particle surface. The cluster-like morphology could be enhanced by use of a polar crosslinking monomer and by sequential reactions. For the polar system, it was found that the reactions with pure monomer were unclean, due to the solubility mismatch of the monomer and the solvent system. This was overcome by a copolymerisation with MMA. The system showed different particle morphologies could be produced by varying the polar monomer content. In one case a sample of pure dumbbell-like particles could be produced. These dumbbell-like particles are thought to be chemical as well as shape anisotropic owing to monomer composition. EPD evaluation for the particles was undertaken and showed that all particles can become highly charged in low dielectric constant media, but that the shape anisotropic particles are prone to adsorption to the cell walls and electrodes.The work outlined in this thesis shows the first reporting of shape anisotropic polymeric particles produced in low dielectric constant solvents system.

No description available.