Acrylic resins used as polymeric binders in automotive coatings are complex copolymers containing reactive functional (often hydroxyl) groups. A better understanding of the copolymerization kinetics of these monomers is required in order to ensure uniform distribution of the functional groups among the polymer chains over the course of production. Free radical copolymerization propagation kinetics of styrene (ST) with 2-hydroxyethyl methacrylate (HEMA) and 2-hydroxyethyl acrylate (HEA) have been investigated both in bulk and solution, using pulsed-laser polymerization (PLP) combined with size exclusion chromatography (SEC) and proton NMR. All of the solvents examined (n-butanol, toluene and DMF) affect ST/HEMA copolymer composition relative to bulk polymerization, while the effects on propagation rates suggest that hydrogen bonding interactions need to be explicitly considered. Semibatch reactions of ST/HEMA, butyl acrylate (BA)/HEMA and butyl methacrylate (BMA)/HEMA have been carried out in xylene, DMF and 1-pentanol at 110 and 138 °C. The variation in monomer composition for the three solvents agrees with the kinetic studies. It was found that polymer molecular weight is strongly affected by solvent choice and operating conditions, partially due to branching reactions caused by impurities from commercial HEMA monomers. PLP and 13C-NMR analysis indicate that no backbiting occurred during polymerization of HEA, and it is shown that H-bonding disrupts the backbiting mechanism found for other acrylates. Thus, semibatch production in n-butanol can reduce branching and increase molecular weight of BA homopolymers by a factor of five compared to polymerization in xylene. / Thesis (Ph.D, Chemical Engineering) -- Queen's University, 2013-02-27 16:44:03.871

“The Thiopyran Route to Polypropionates” is a synthetic strategy that involves the stepwise aldol reactions of 6 and 7a to rapidly access stereochemically complex tetrapropionate 8 and hexapropionate synthons 72 or 73. Coupling racemic 7a with any of the four enantioenriched diastereomers 8 with kinetic resolution (KR) is possible with rational design of the reaction using the 'multiplicativity' rule. Thus, any of two of the eight possible aldol adducts, 72 or 73, are selectively available from the same reactants.

Doctor of Philosophy / Department of Mechanical and Nuclear Engineering / Mingchang (James) Chen / To describe the behavior of a gas composed of spherical particles that rotate, the kinetic theory approach is presented. First-order approximations to the Boltzmann-Curtiss transport equation yield conservation equations that govern the translational velocity and rotation of the particles. The resulting equations match the form of the equations of morphing continuum theory (MCT), a theory derived from the principles of rational continuum thermomechanics. A direct comparison of corresponding terms provides expressions related to the new coefficients within MCT, showing a clear departure from classical expressions derived from a kinetic treatment of classical fluids. The identical expressions for the coefficients in the Cauchy stress and viscous diffusion terms in the kinetic linear momentum equation suggests that the coupling coefficient introduced by MCT outweighs the contribution of the classical kinematic viscosity. The kinetic theory equations reduce to the form of the Navier-Stokes equations when the local rotation is equated to the angular velocity, but the predominance of the coupling coefficient results in a viscous term that differs slightly from the classical expression derived using the Boltzmann distribution function. For simple cases of irrotational and incompressible flows, the kinetic equations mimic the form of the classical momentum equations derived from classical kinetic theory. This result is consistent with the fact that the difference between the two kinetic approaches is the local rotation of spherical particles. Preliminary numerical simulations of the MCT governing equations are discussed, with an emphasis on the importance of the new coupling coefficient. Turbulent incompressible profiles are achieved by setting dimensionless parameters to particular values. The key parameter involves the ratio of the coupling coefficient to the kinematic viscosity. The relationship between the coupling coefficient and kinematic viscosity is shown to be the driving force for the development of transitional and turbulent boundary layer profiles. Compressible turbulence results are generated using the same dimensionless parameter values that generated turbulence in the incompressible case. For supersonic flow over a cylinder, MCT displays an inverse energy cascade from small to large scales. In addition to visualizing turbulent processes, the results from MCT display the importance of coupling the linear and angular momenta equations, which is strengthened when the coupling coefficient increases. The expressions from kinetic theory coupled with the numerical results in MCT indicate that the physical phenomena driving a fluid composed of spherical particles depends heavily on the physical properties of the coupling coefficient.

In this dissertation, we investigate the n=0 Geodesic Acoustic Modes (GAM) in the framework of both magneto-hydrodynamics and kinetics. In MHD, the purpose is to understand the numerical results out of the CASTOR code (1). Effects of energetic particle are ignored. The leading perturbation is the density perturbation, which leads to a local GAM. The coupling of density perturbation to the magnetic perturbation, which is treated to be smaller, leads to global a GAM. We recover the numerical results from the CASTOR code and obtain and analytical solution to the radial eigen-mode equation though asymptotic matching. To understand recent experimental results on DIII-D (2) a kinetic theory is constructed in which magnetic perturbations are neglected and energetic ions are treated on the same footing as the thermal species based on drift kinetics. Not only do the energetic particles destabilize the local GAM induced by thermal species, but they are also crucial to establish the global GAM due to their large orbit shifts. Polarization of thermal ions is included. A mechanism for fast GAM excitation through NBI is proposed, based on our local kinetic GAM theory when there exists a loss boundary in pitch angle. / text

No description available.

No description available.

No description available.

The kinetics of the reaction of atomic sulfur and nitrogen dioxide have been investigated over the temperature range 298 to 650 K and pressures from 14 - 405 mbar using the laser flash photolysis - resonance fluorescence technique. The overall bimolecular rate expression k (T) = (1.88 ± 0.49) x10-11 exp-(4.14 ± 0.10 kJ mol-1)/RT cm3 molecule-1 s-1 is derived. Ab initio calculations were performed at the CCSD(T)/CBS level of theory and a potential energy surface has been derived. RRKM theory calculations were performed on the system. It is found that an initially formed SNO2 is vibrationally excited and the rate of collisional stabilization is slower than the rate of dissociation to SO + NO products by a factor of 100 - 1000, under the experimental conditions.

Thesis (Ph.D.)--University of the Witwatersrand, Faculty of Science, 2013.

This research examines the zone between environment and interior, the architectural façade, for the potential to develop a new form of composition based on kinetic pattern. Within contemporary architecture there is a growing interest in kinetics. Intelligent façades for example, manifest kinetics in the form of a responsive skin that adapts to changing environment conditions and user occupancy, continuing the trajectory of functionalism. Media façades by contrast, are driven by an interest in the recasting of architectural surface as a zone of interactivity, with the potential to engage users with public art works or embed socio-cultural information. Regardless of the design intent, the emerging field of kinetic façades offers the challenge of developing a sophisticated approach to the design of motion. As evidenced by a review of theory and practice, there is a lack of fundamental knowledge about the possibilities offered by kinetics. / Through the lens of morphology, this thesis explores the possibilities of kinetic composition afforded by façades in motion. The emphasis is on the underlying structure of kinetic form, independent of physical scale or materiality. Kinetics is defined in spatial terms: actual movement through geometric transformation in space (translation, rotation, scaling); or through controlling material properties of elasticity and mass to produce movement. Composition is analyzed in terms of pattern, defined as the relative movement of individual kinetic parts in time and space - the way in which multiple singular kinetic events cluster, or propagate, across a facade over time. A morphology of pattern is developed by three interrelated questions. What design variables influence kinetics, what is the theoretical range, and what nomenclature may robustly describe a morphology of pattern? / An original framework for conceiving design variables is proposed. The framework revolves around diverse approaches to data sampling and control systems, alongside the typical architectural emphasis on the design of the physical components. These three interrelated design activities are conceived in terms of ‘decision planes’. Specification of variables on each plane and in relation to time, determine the spatio-temporal limits, or what is termed as the ‘variable space’, from which patterns will emerge. / This conceptual framework has been used to structure a methodical series of computer animations, which explore range of pattern. In a similar vein to the tradition of façade study drawings, a diagrammatic approach to animation has been developed. The adoption of a non-realistic mode of representation is intended to focus attention on ‘movement itself’, independent of physical scale, materiality or figurative associations. Through analysis and discussion of the animations, it is proposed that morphology of kinetic pattern is robustly described through a nomenclature based on state change. It is proposed that three recognizable states reoccur-waves, folds and fields. State change is based on the principle of internal variance within these three simple states, and intermediate states that allow transition by degree and kind. Similar to the nomenclature for describing clouds, this provides a robust and extendable approach, allowing multiple intermediate states to be conceived in relation to the wave, fold and field definitions. / The framework for conceiving variables that influence pattern and the state change morphology provide the means to improve understanding in the particular realm of kinetic façade composition. The framework is presented in generic form and a particular instance is developed based on an analysis of key references. This provides a model to conceive the multiple variables that influence kinetic composition, while the morphology provides a low resolution map for designers, identifying the most distinctive forms and providing a scaffold for research by design. Further work on extending these contributions to knowledge is outlined, including the description of a simulation environment calibrated to the physical constraints of materials and technology.