Ice buildup on structures leads to problems that include reduced performance, structural damage and power outages. It is therefore important to limit the energy required for removal of ice from substrates to minimize buildup. Understanding the mechanism of ice adhesion and its dependence on variables like coating thickness, stiffness, surface free energy and morphology is critical for minimizing adhesion. Despite several developments in “icephobic” coatings, which are those that have low ice adhesion, it is important to understand adhesion on the fundamental level to make way for advanced coatings. To do so, a study has been carried out that explores key variables affecting ice adhesion using a commercially available silicone, Sylgard 184®. Sylgard 184 is a two-part, platinum cured silicone elastomer available from Dow Corning with good physical and chemical stability and is used in widely diverse research studies. The thermodynamic work of ice adhesion is related to the receding contact angle θ_r of water by Equation 1. wa≈ γ_w (1+cos⁡ θ_r) Eq 1. where γ_w is the surface tension of water. Considering an elastomeric substrate and ice as a rigid cylindrical adherent, the Kendall modelcan be adapted to relate peak removal force (Pc) with work of adhesion (wa), modulus (K), thickness (t), and radius (a) according to Equation 2. Pc ∝ πa^2 ((2wa K)/t)^(1⁄2) Eq. 2 Considering these relationships, hydrophobic materials with low surface energies and high receding contact angles are generally predicted to show low adhesion. To begin to understand details, the force required to remove an ice cylinder from the silicone elastomer Sylgard 184 was investigated by focusing on three variables: coating thickness, modulus and cure temperature. “Cure” refers to the network formation or crosslinking within the material. The Wynne research group has previously established a surprising dependence of qR on Sylgard 184 cure temperature.In this thesis, the relationship among variables noted above was examined by measuring Pc for Sylgard coatings. Additionally, effects of test temperature on ice adhesion strength was studied. Surface characterization methods including ATR-IR (attenuated total reflectance infrared spectroscopy), DCA (Wilhelmy plate dynamic contact angles) and AFM (atomic force microscopy) were employed. In summary, defined processing conditions were found optimum for minimizing ice adhesion to Sylgard coatings.

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This comparative study analyzes two rebel groups that ended their respective civil wars through negotiations and came to power in the first post-war elections. The two cases being the African National Congress in South Africa and the Zimbabwe African National Union – Patriotic Front in Zimbabwe. Specifically the thesis examines rebel institutions and behaviors during armed conflict to assess in what ways they were tolerant or intolerant. The reason for the focus on tolerance and intolerance is that it is viewed as an important factor in how these two parties have related to political opposition after the war. This study shows that there are several similarities in terms of the presence of intolerance in the two cases, which leads to the conclusion that levels of tolerance during the armed conflict can not, on its own, explain the diverging paths of the two cases in the post-war period.

Breast cancer is the most common cancer among Canadian women and 14-20% will develop lethal metastases within 5 years. A potential novel therapeutic target is Focal Adhesion Kinase (FAK), a cytoplasmic tyrosine kinase. FAK’s expression is inversely correlated with survival and is known to regulate cell migration, proliferation and invasion. While tyrosine kinase inhibitors are historically ineffective as single agents, they are commonly used as part of combination therapies. Therefore, given its central role in tumor cell biology and cell signaling, we hypothesized that inhibiting FAK in combination with pharmacological agents commonly used to treat metastatic breast cancer patients will result in enhanced anti-tumor activity. We combined a commercial FAK inhibitor (PF-562271) with a range of chemotherapeutic agents commonly used to treat metastatic breast cancer and searched for synergistic partners. Only DNA topoisomerase inhibitors showed potential to synergistically reduce cell viability when paired with low doses of the FAK inhibitor. However, the combination does not induce an increase in cell death or apoptosis. It was then discovered that both agents in isolation and in combination produce increased levels of ROS, a toxic metabolite. This, along with other more preliminary data, provides clues for a novel proposed mechanism of action for this interaction.

Phenol Formaldehyde (PF) and polymeric isocyanate (pMDI) are the two main types of adhesives used in the production of structural wood-based composites. Much is unknown about various aspects of adhesion between these two types of resins and wood. The present research describes the development of techniques which will permit an enhanced understanding of 1.) the extent of cure of PF within a wood based composite, 2.) the scale of molecular level interactions between PF and pMDI and wood, 3.) mechanical performance and durability of wood-adhesive bonds. Correlations were established between conventional methods of characterization of neat PF (thermomechanical analysis, swelling studies) and measurements made using 13C CP/MAS NMR. These correlations were then utilized to characterize PF cured in the presence of wood. The use of 13C labeled PF allowed estimates of relative degrees of resin conversion to be made. The use of 13C and deuterium labeled PF allowed qualitative estimates of resin molecular rigidity to be made. The scale of molecular level interactions between PF and pMDI and wood was probed using NMR relaxation experiments. Evidence was shown to suggest the formation of an interpenetrating polymer network (IPN) morphology existing at both types of wood-resin interphases. The formation of the IPN morphology was strongly influenced by resin molecular weight, cure temperature and the presence of solvent. A new test geometry for the evaluation of the fracture toughness of wood-adhesive bonds was developed. Consistent and reliable results were obtained. It was found that low molecular weight PF possessed enhanced durability over high molecular weight. / Ph. D.

This work reports the elucidation of the structure of a copolymer generated by the cross- catalyzed reactions of PF and pMDI prepolymers.  The electronic behavior of phenolic monomers as perturbed by alkali metal hydroxides in an aqueous environment was studied with 1H and 13C NMR.  Changes in electronic structure and thus reactivity were related to solvated ionic radius, solvent dielectric constant, and their effect on ion generated electric field strength. NMR chemical shifts were used to predict order of reactivity for phenolic model compounds with phenyl isocyanate with good success.  As predicted, 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under neutral conditions and 2-HMP hydroxymethyl groups were more reactive than 4-HMP in forming urethane bonds under alkaline conditions. The structure of the reaction products of phenol, benzyl alcohol, 2-HMP, and 4-HMP with phenyl isocyanate were studied using 1H and 13C NMR under neutral organic and aqueous alkaline conditions.  Reactions in THF-d8 under neutral conditions, without catalyst, were relatively slow, resulting in residual monomer and the precipitation of 1,3-diphenyl urea from the carbamic acid reaction.  The reactions of phenol, 2-HMP, and 4-HMP in the presence of TEA catalyst favored the formation of phenyl urethanes (PU). Reactions with benzyl alcohol, 2-HMP, and 4-HMP in the presence of DBTL catalyst favored the formation of benzyl urethanes (BU).  Reactions of 2-HMP and 4-HMP led to formation of benzylphenyldiurethane (BPDU).  DBTL catalysts favored formation of BDPU strictly by a benzyl urethane pathway, while TEA favored its formation mostly via phenyl urethane, although some BU was also present.  Under aqueous alkaline conditions, 2-HMP was more reactive than 4-HMP, exhibiting an enhanced reactivity that was attributed to intramolecular hydrogen bonding and a resulting resonance stabilization of the phenolic aromatic ring. ATR-FTIR spectroscopic studies generated real time structural information for model compound reactions of the cross-catalyzed system, differentiating among reaction peaks generated by the carbamic acid reaction, PU and BU formation.  ATR-FTIR also permitted monitoring of propylene carbonate hydrolysis and accelerated alkaline PF resole condensation.  ATR-FTIR data also showed that the overall reaction stoichiometry between the PF and pMDI components drove copolymer formation.  Benzyl urethane formation predominated under balanced stoichiometric conditions in the presence of ammonium hydroxide, while phenyl urethane formation was favored in its absence.  Accelerated phenolic methylene bridge formation became more important when the PF component was in excess in the presence of sufficient accelerator.  A high percentage of free isocyanate was present in solid copolymer formed at ambient temperature. The combination of ammonium hydroxide and tin (II) chloride synergistically enhanced the reactivity of the materials, reducing the residual isocyanate. From 13C CP/MAS NMR of the copolymer, the presence of ammonium hydroxide and tin (II) chloride and the higher PF concentration resulted in substantial urethane formation.  Ammonium hydroxide favored formation of benzyl urethane from the 2-hydroxymethyl groups, while phenyl urethane formed in its absence.  The low alkalinity PF resole with ammonium hydroxide favored benzyl urethane formation.  Comparison of these results with the 13C NMR model compound reactions with phenyl isocyanate under alkaline conditions confirmed high and low alkalinity should favor phenyl and benzyl urethane formation respectively.  These cross catalyzed systems are tunable by formulation for type of co-polymer linkages, reactivity, and cost. / Ph. D.

In the early 2000 the government of Zimbabwe was targeted by sanction and restrictive measures imposed by the United States and the European Union. Sanctions have for decades been used as a method to delegitimize and isolate wrongdoers in order to promote democratic transitioning. Unfortunately, in many cases this foreing policy method has failed to transform authoritarian ruling into democracy as the intentions, purposes and outcomes of sanctions have not been aligned. With a methodological qualitative approach, this study will utilize a case study research design with an semi structured interview approach to investigate the effects of sanctions against the government of Zimbabwe. Does sanctions result in the desired outcome? What consequences are caused by the design of sanctions for third world states? Sanctions have challenged the Government of Zimbabwe’s response to economic crises, unemployment and polarisation of internal politics together with many other outcomes. However, the ZANU-PF leadership have surprisingly gained tremendous support in the south African region in their anti-imperialistic fight against the west. In addition, this study questions and criticizes the imposition of sanctions upon weaker states by wealthy and dominant nations in world politics. To support the argument that sanctions operate in contradiction to their intentions and purposes, a detailed empirical examination and analysis of these four categories will be presented: political effects, economy, internal conflict and policy making.

Addressing global climate change will require increasing sustainable energy usage. Cofiring biomass fuels with coal for electrical power generation is an efficient, cost effective method of CO2 mitigation. This work is an experimental investigation of the flame structure and nitrogen chemistry differences occurring between coal, biomass and cofiring flames. A pilot-scale facility was fired with a dual-feed low-NOx burner capable of independently conveying 2 separate fuels unblended to the burner. Spatially detailed gas species measurements were made for 8 flames, including a coal, straw, finely ground straw, wood, and 4 straw/coal cofiring flames. Particle samples were also obtained from 5 of the flames. Intermittent flamelets were frequently observed in the flames. Viewing the substructure of the flame as individual flamelets provides critical insight for the interpretation of the data. The biomass and cofiring flames show larger flame volumes due to increased primary momentum, increased volatile yields, and differences in fuel particle characteristics (size and shape). The straw and cofiring flames also include secondary flame structures. The secondary flames result from delayed reaction of the straw “knees" due to differences in fuel characteristics. Biomass fuel-N was shown to evolve primarily through NH3, while the coal showed roughly equal amounts of NH3 and HCN. Due to increases in the flame volume and greater NH3 release within these larger fuel-rich regions, as well as lower fuel-N content, effluent concentrations of NO for the biomass and cofiring flames are lower than the coal flame. In-flame reduction of NO corresponds spatially to the presence of NH3, suggesting advanced reburning. Lower fuel-N contents are thought to increase the overall NO production efficiency, but this effect is uncertain for this work due to differences in flame structure and fuel-N chemistry. A mixing model based on intermittent flamelet behavior is included. The model uses dual-delta functions (DDF) to represent lean and rich eddies passing through a sampling volume. Both the beta-pdf and the DDF model were fit to data obtained in this study and compared. The beta-pdf model was unable to capture intermittent behavior. The DDF model was able to represent intermittent behavior, but produced physically unrealistic results.

Bio-oil produced from biomass by the fast pyrolysis method is promising as a renewable fuel and as sources of industrial chemicals. In this study, lower cost separation methods of organic acids such as acetic and formic acids and pyrolytic lignin fraction present in bio-oil were investigated to provide basic data needed for future industrial production procedures. The calcium oxide method and a quaternary ammonium anion-exchange resin method were studied to separate organic acids as respective salts and the methanol-and-water method was studied to separate the water-insoluble pyrolytic lignin fraction. The calcium oxide and anion-exchange methods were shown to be effective in separation of organic acids, although further improvements would be needed. The pyrolytic lignin separation method was also shown to give lignin fraction that is effective for up to 40% replacement of phenol in the oriented strand board core-layer binder PF resins.

Patient-voice clauses within the symmetric voice system of Balinese disallow any extraction from the external-argument position, while definite external arguments are blocked from occurring altogether. The former fact is traditionally taken as evidence for syntactic ergativity in Austronesian. The latter fact has recently been argued to provide evidence for postsyntactic case licensing via adjacency with the verb. In this article, we offer a simple alternative explanation for the in-situ properties of patient-voice agents in Balinese—one that does not make reference to case.We argue that patient-voice heads come with a feature that triggers removal of the external argument’s DP shell, resulting in the loss of a determiner and a category-D feature that would otherwise enable extraction.