McGill University Thèses et mémoires publiés en 1988

Reevaluation of organosulfur heats of formation resulted in the conclusion that the sulfur-sulfur bond of aliphatic disulfides is nearly 15 Kcal/mole stronger than the disulfide carbon-sulfur bond energy. Semi-empirical calculations using AM1, MNDO and MINDO/3 from the AMPAC program package confirmed these results and clarified their relative impact on organosulfide and disulfide properties. Existing organoselenium bond energy data were also reevaluated and erroneous assumptions discovered. New bond energy estimates were made via a new procedure. It was concluded that the selenium-selenium bond is also stronger than the selenium-carbon of aliphatic diselenides. The above results led to the conclusion that loss …  Lire la suite

Determining the optimal long-term operating policy of a multi-reservoir power system requires solution of a stochastic nonlinear programming problem. For small systems, the solution can be found by dynamic programming, but for large systems no direct solution method exists yet, so that one must resort to mathematical manipulations to solve the problem. This thesis presents a very efficient procedure for the case where high correlation exists between the state variables. It consists in performing principal components analysis on the trajectories to find a reduced model of the system. The reduced model is then substituted into the operating problem and the …  Lire la suite

The photolysis of bilirubin IX-$ alpha$ in organic solvents leads to both EZ/ZE isomers and lumirubins, with the latter being formed from the former. The relative yields of the various photoproducts is markedly dependent on the solvent. Small amounts of photoproducts are also produced on irradiation of aqueous bilirubin solutions; however, the addition of human serum albumin increases the efficiency of the photoreaction, predominantly by isomerization of bound bilirubin. The formation of photoproducts from aqueous bilirubin solutions increases the rate of adsorption onto cholestyramine but not peptide-substituted polyacrylamide resins. The photoproducts, principally lumirubins produced by irradiation of bilirubin in DMSO, …  Lire la suite

Structural effects in small molecule and polymer systems have been studied through heat capacity measurements (small molecule systems), phase diagrams and heat of mixing measurements (polymer systems). It has been found that structure due to molecular antipathy i.e. large H$ sp{ rm E}$ and G$ sp{ rm E}$ manifests itself through a W-shape C$ sbsp{ rm p}{ rm E}$ which is found to be a summation of two contributions to the thermodynamics: random and non-random. An excellent correlation is made between C$ sbsp{ rm p}{ rm E}$ and the concentration-concentration correlation function (S$ sb{ rm CC}$). The non-randomness effect increases …  Lire la suite

Automatic analysis methods based on multichannel radiance data measured by the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA7 and NOAA9 satellites are used to: (a) detect clear and cloudy areas above coastal regions; and (b) detect clouds and to estimate cloud amount above the Arctic. Channels 1 2 and 4 of the AVHRR were employed to separate clear from cloudy radiances above coastal regions. All AVHRR channels were used above the Arctic. A large number of orbits were analysed automatically and the analysis results were compared to manual analyses performed by an independent observer and to published analyses. …  Lire la suite

A theoretical and experimental study is presented of texture evolution in hcp zirconium deformed at high temperatures. It is shown that, within the temperature range in which nuclear components are fabricated, the development of crystallographic texture is controlled by the simultaneous activation of $ langle$a$ rangle$ and $ langle$c + a$ rangle$ slip. This is demonstrated by experiments on Zr-2.5 Nb and unalloyed Zr deformed along three of the four elementary strain paths: axisymmetric elongation and compression and pure shear. Further experimental work on the axisymmetric deformation of unalloyed Zr and Zr-20 Nb shows that the influence of the bcc …  Lire la suite

Early image understanding seeks to derive analytic representations from image data. This thesis presents steps towards this goal for three-dimensional imagery by focusing on the inference of trace points (points belonging to surfaces), and the estimation of associated differential structure given by the principal curvature and direction fields over smooth surfaces. Computation of these fields is posed as the determination of a cross section through the bundle of curvature frames over the estimated trace. Algorithm robustness and the stability of results are essential for analysis of real images; to this end, I present a functional minimization algorithm where the principal …  Lire la suite

A new method for on-line laser spectroscopy of radioactive atoms based on the resonant ionization spectroscopy of laser desorbed radioactive samples has been devised. An experimental set-up has been installed on-line at the ISOCELE mass separator in Orsay (France) and experiments have been performed on the transitional nuclei region around Z = 79. Four new isotopes $ sp{194,196,198,199}$Au have been added to the series of the isotopic shift measurements in gold and results on the neutron deficient isotopes down to $ sp{186}$Au have been obtained, confirming the nuclear ground-state shape transition from oblate to prolate between $ sp{187}$Au and $ …  Lire la suite

This study considers a number of problems which remain in nonlinear consolidation modelling and prediction, despite the considerable research effort which has already been devoted to the subject. Nonlinear consolidation models refer to those models capable of accounting for material nonlinearity either explicitly, in the formulation of the governing equation, or implicitly in the numerical-solution technique. A nonlinear model can be characterised by its generality, appropriateness for modelling consolidation and prediction-capability. These three characteristics are not consistent; a model's superiority with respect to one characteristic does not imply its overall superiority. This inconsistency between the characteristics is resolved by a …  Lire la suite

This thesis consists of two main parts. The first part is the musical score of an original composition for piano and full orchestra entitled "Confluence. This is a single movement work of approximately thirteen minutes duration. The second part is an essay containing a detailed aesthetic, conceptual and technical analysis of the musical work.  Lire la suite

I present the measurements, analysis and results obtained with the NA34 experiment at the CERN European laboratory, on the global characteristics of particle production in ultra-relativistic oxygen-nucleus collisions, at incident energies of 60 and 200 GeV/nucleon. The observed properties of the particle flow are analysed in the framework of phenomenological models inspired by quantum chromodynamics. From this analysis, novel information emerges concerning the mechanisms and space-time evolution of the soft-hadronic processes in short-lived extended volumes of matter at extreme densities and temperature. We consequently study the parameters and critical conditions under which nuclear collisions could allow the observation of a …  Lire la suite

McGilvray, James (Supervisor)  Lire la suite

The overall goal of this thesis work has been the construction of liposomes that can be used to deliver biologically active molecules efficiently into the plasma membranes of animal cells in tissue culture. In an initial series of studies, we examined how various mixtures of neutral lipids commonly used in reconstitutions of membrane proteins (phosphatidylcholine [PC], sphingomyelin, phosphatidylethanolamine [PE] and cholesterol) influence the divalent cation- and polyethyleneglycol (PEG)-mediated interactions of lipid bilayer membranes. The major novel findings from these studies were: (1) that sphingomyelin inhibits vesicle aggregation and fusion even more severely than does phosphatidylcholine; (2) that cholesterol can significantly …  Lire la suite

Dans la mesure, cette oeuvre d'imagination repond aux crit6res de f6erie de Tolkien en tant que conte "eucatastrophic" qui montre le chemin vers "I'Evangelium", cette eschatalogie qui se situe au moment o0 la volontê de Dieu est accomplie et les effets de la chute sont surmontes, Tolkien peut etre. considers comme un auteur biblique. Le fait qu'il est voulu que son oeuvre soit lue en tant qu'"&angile", "la bonne nouvelle du Royaunie de Dieu" est suggêre par diffèrentes choses: les allusions faites a la mythologie biblique et classique, la vision linêaire de l'histoire, la presentation du texte en tant que …  Lire la suite

Experiments were conducted to investigate the effect of reducing dietary anion-cation balance (AC-balance), defined as meq $ sp circ$(Sodium + Potassium)-(Chloride + Sulfur) S, on calcium (Ca) metabolism. Reducing the dietary AC-balance from +314 to $-22$ (meq kg$ sp{-1}$ dry matter (DM)) did not affect plasma Ca level but reduced Ca retention mainly due to a 10-fold increase in urinary Ca excretion with similar rate of apparent absorption. It also decreased urine pH and titratable acidity. The response to induced hypocalcemia created by the infusion of 4.6% EDTA solution revealed that reducing dietary AC-balance from +354 to +37 (meq kg$ …  Lire la suite

The properties of tubulins from Brugia malayi, B. pahangi, Nippostrongylus brasiliensis and rat brain were compared. Tubulins from all nematodes and rat brain were partially purified by polylysine agarose chromatography, those of brain also by cycles of assembly/disassembly, and all by taxol-induced assembly. The tubulins were compared with respect to concentration ($ mu$g tubulin/mg soluble protein), drugs binding and isoforms. The tubulins of B. malayi and B. pahangi were similar. However, the tubulin from these filariae were different from those of N. brasiliensis. Even larger differences were detected between the nematode tubulins and those of rat brain. However, all tubulins …  Lire la suite