Thesis (Ph.D.)--York University, 2004. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 160-172). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99168

Thèse--Doct._ing--Aix-Marseille 1, 1971. / Bibliogr. f. 81-87.

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We investigated the different percentage of glycerol or ethylene glycol doped into PEDOT:PSS as anode buffer layer in OSC. The electrical, optical and physical properties of PEDOT:PSS were measured before and after adding glycerol or ethylene glycol. Their optical transparency was almost the same by UV-Vis spectrophotometer. Their HOMO value, measured by PESA, was around 5.1eV. Modified PEDOT:PSS with proper concentration addition increased its conductivity. Finally, surface roughness of PEDOT:PSS layer increased with higher concentration of addition resulted in bad film-forming from spin coating process. We fabricated polymer solar cells with modified PEDOT:PSS as anode buffer layer. The devise was consisted of ITO/PEDOT:PSS (different doping concentration of glycerol or ethylene glycol ) /P3HT:PCBM /Al and measured device parameter of solar cell with sunlight simulation of AM1.5G 100mW/cm2 . We found that improvement of power conversion efficiency of polymer solar cell from 2% to 3% and short-circuit current was improved for 32%, with modified PEDOT:PSS as anode buffer layer. We suggested that the improved short-circuit current was originated from increased conductivity of PEDOT:PSS that was modified by glycerol or ethylene glycol. Finally power conversion efficiency of polymer solar cell was increased with modified.

The ability to repair damaged mammalian axons to re-establish functional connections continues to be a goal for neuroscientists. Following axonal severance, proximal segments of mammalian axons seal themselves rapidly at the lesion site. Distal segments of severed mammalian axons undergo Wallerian degeneration within 24-72 hours. Prior to the onset of degeneration, distal axonal segments remain electrically excitable. The work described in this dissertation demonstrates that polyethylene glycol (PEG), a hydrophilic polymer, can rapidly repair severed axons by fusing the plasmalemmas of two closely apposed distal and proximal axonal segments. This plasmalemmal fusion restores morphological integrity of severed axons and their ability to conduct action potentials across the injury site. The ability to fuse proximal and distal severed axonal segments using PEG is improved when the axonal segments are exposed to antioxidants, such as melatonin and methylene blue, and also when microsutures provide additional support in transected sciatic nerves. The restoration of axonal continuity by PEG-fusion restores function, improving behavioral recovery in rats with crush-injured sciatic nerves, as well as those in which the sciatic is complete transected. / text

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Thesis (M.Sc.)--York University, 2007. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references. Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR32003

Dialkyl carbonates are important industrial compounds that have a low toxicity and are readily biodegrade, also replacing some highly toxic and corrosive reagents in organic chemistry. There are a number of synthetic routes towards the synthesis of dialkyl carbonates, including two commercial processes (ENIChem S.p.A. and UBE Industries, LTD). The ENIChem process involves the carbonylation of methanol in the presence of CuCl2 as a catalyst. The major drawback of this process is in the use of an explosive gas mixture (CO/O2) under certain conditions. The UBE process is a two step reaction, whereby the methanol reacts with O2 and NO in the presence of a PdCl2 catalyst to form methyl nitrite and water, followed by carbonylation of methyl nitrite to form DMC and reform NO. The major drawback associated with this process is in the combination of methanol, nitric oxide and oxygen which is also explosive under some conditions. The transesterification reaction between a cyclic carbonate and an alcohol in the presence of a catalyst provide an alternative route towards synthesis of dialkyl carbonates, producing a glycol as by-product. This synthetic route is environmentally friendly, decreases explosion possibilities, and the reagents employed in this process are less hazardous than those of other processes. The main aim of this study was to identify and optimise the catalyst systems that could promote the transesterification reaction effectively. A number of homogeneous and heterogeneous, acidic or basic catalysts were evaluated during this study. The study revealed that basic homogeneous catalysts such as TBD, DBU, DBN, MTBD, DABCO, and Verkade bases are effective for the transesterification reaction. The basic heterogeneous catalysts such as Amberlites® IRA 96, IRA 67 and IRA 400 showed good catalytic behaviour, but they eventually became deactivated. On the other hand, homogeneous Lewis acids such as La(OTf)3, Gd(OTf)3, and Sm(OTf)3 demonstrated good activity, even though they need high temperatures, i.e. 150 °C. The heterogeneous acidic systems such as Amberlyst® 15, Amberlyst® 36, silica, alumina, etc., showed much lower activity, if any was observed. ix Due to the fact that these reactions were carried out above room temperature and analysed at room temperature in the GC, it was important to understand the equilibrium shift under such temperature variations, and NMR studies were used here. There was no significant difference in equilibrium conversion between the NMR reactions and the autoclave reactions (analysed in a GC), indicating slight influence of temperature variation. The results obtained from the NMR study were used to calculate the reaction kinetics. The calculations indicated a direct proportional increase of the rate with respect to the catalysts pKa values. / Prof. D.B.G. Williams

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Les coulis de glace sont des réfrigérants secondaires considérés comme propres. Ils sont notamment utilisés dans la climatisation, la conservation d’aliments ou certaines applications médicales. Ils se composent de particules de glace et d'un mélange d'eau liquide et d'un additif (ici le propylène-glycol ou l’éthylène-glycol) utilisé pour abaisser le point de congélation de l'eau. Les caractéristiques rhéologiques des coulis de glace ont été mesurées à l'aide d’un rhéomètre de type Discovery HR2 équipé d'une géométrie de type "vane". On considère trois concentrations initiales de soluté (5%, 14% et 24%) pour les deux additifs et les fractions massiques de glace varient entre 5% et 65%. Les résultats expérimentaux révèlent que les coulis de glace sont généralement des fluides non Newtoniens présentant un comportement rhéofluidifiant ou rhéoépaississant en fonction des conditions expérimentales. Les indices d’écoulement et de consistance impliqués dans le modèle de Herschel-Bulkley ont été évalués selon la méthode des moindres carrés. Les résultats sont finalement validés à partir d’une base de données expérimentales issues de la littérature et les prédictions d'un modèle de réseau de neurones artificiels.