The heterogeneous metallocene catalyst is becoming a very competitive industrially due to its ability to produce tailor-made polymers. The main advantage of the metallocene polymer product is the narrow molecular weight distribution (MWD) and the systematic comonomer distribution along the polymer chains. Therefore, the metallocene polymer product has well-defined mechanical and optical properties. The aim of this thesis is to investigate the effects of the silica support on the reaction kinetics and micro properties of the heterogeneous metallocene catalyst system. These investigations include studying the influence of the pore volume, surface area, particle size distribution, and the surface chemical characteristics of silica support on the catalyst performance. The experiments showed that the silica type has an influence on the kinetic behavior. For instance, silica with a lower pore volume shows an induction period when compared with higher pore volume silicas. Moreover, the silica type has a clear influence on catalyst activity and polymer morphology. The smallest silica particles produced the highest activity among the other sizes regardless of silica type. The supported catalysts were characterized and linked to the silica type and size in terms of catalyst activity and polymer morphology. Each catalyst in terms of silica type behaved similarly regardless of type of alkylaluminum used in the formulation. The micro properties of the produced polymers, such as MWD and chemical composition distribution (CCD), were studied to understand the effects of the type and size of silica support and co-catalyst on these properties. The silica types showed no effect on the MWD, but had a slight effect on the CCD. Silica with a high pore volume had a stronger more comonomer response. However, the silica particle size had an influence on the CCD, with less comonomer incorporation observed with smaller silica particles. Finally, triethylauminum was observed to produce polymer with a different MWD when compared with other alkylaluminums. However, all alkylaluminums used in this work had no effect on the CCD of the produced polymer regardless of silica type. / Thesis (Master, Chemical Engineering) -- Queen's University, 2012-04-11 13:37:09.878

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The aerosol diluter characteristics of three different systems, the single-stage and the two-stage TSI 379020A rotary disk thermodiluters and Dekati FPS-4000 ejector diluter, were tested using gases and particles over a range of dilution ratios. The upstream and downstream gas and particle concentrations of the diluters were measured in real-time to compute the actual dilution ratio achieved by the three systems. Dilution ratios from approximately 15 to 100 were found to fall within the expected operating error margin of ± 10% for CO2 and CH4. Dilution ratios covering a similar range were also achieved to within ± 10% for particles with diameters from 9.3 to 200 nm. However, when engine exhaust was sampled, significant loss of particles smaller than 29.4 nm occurred during the dilution process. As the dilution ratio increased, the deviation from the expected value increased due to an increase in measurement uncertainty.

The aerosol diluter characteristics of three different systems, the single-stage and the two-stage TSI 379020A rotary disk thermodiluters and Dekati FPS-4000 ejector diluter, were tested using gases and particles over a range of dilution ratios. The upstream and downstream gas and particle concentrations of the diluters were measured in real-time to compute the actual dilution ratio achieved by the three systems. Dilution ratios from approximately 15 to 100 were found to fall within the expected operating error margin of ± 10% for CO2 and CH4. Dilution ratios covering a similar range were also achieved to within ± 10% for particles with diameters from 9.3 to 200 nm. However, when engine exhaust was sampled, significant loss of particles smaller than 29.4 nm occurred during the dilution process. As the dilution ratio increased, the deviation from the expected value increased due to an increase in measurement uncertainty.

The consistency of fundamental constants is assumed in the Standard Model. However, new physics theories allow them to be dynamical. Different tests can be made at various epochs of the universe. In particular, current bounds at the time of emission of the Cosmic Microwave Background (CMB) permit variations up to 1% of their present values. A change of this order can produce an accumulation of tritium which would later decay and modify the ionization history of the Universe by up to O(0.1%). This Tritium Decay Scenario (TDS) can modify the CMB to an observable level and thus provides a new probe of Varying Fundamental Constants (VFC). We analyze the WMAP 7-year and SPT data with respect to the TDS and find no evidence for VFC. The data disfavors a portion of the parameter space at 95% Confidence Level (CL). We forecast the sensitivity of Planck to the TDS and find that a larger range of parameters can be excluded at 3σ CL. / Graduate

With the deep exploration of particle physics, particle accelerators, detection methods, data recording and processing, and application of computing technology are continuously developing. It has not only brought progress in particle physics, but also promoted the development of the Science and Technology. The main focus of this thesis is data recording and processing. It provides a calibration method for pulses processed by ADCs. It uses some existing filters to achieve the accurate parameters of pulses and existing concept to do the comparison among filters. The  FPGA implementation scheme is also discussed in the paper.

A low-clay version of fine translucent china was designed to have desired properties and acceptable behaviour during manufacture. Low-clay contents of 10 to ISw/o were employed to reduce the deterious effects of preferential clay particle alignment and its adverse effect on colour. For example, alignment of clay particles in cast wares causes anisotropic drying and firing shrinkages and these cause distortion. Replacing clay with a pre fired body with low Fe and Ti contents, as in the present case, allowed a very white material to be produced. The prefired body was made with calcium carbonate, aluminium trihydroxide, quartz and a small fluxing addition of an hydrated magnesIUm carbonate. Desification of a whiteware is enhanced by increasing volume fraction of the viscous liquid and reducing by its viscosity. Both of these also enhance sagging. Consequently, compositional change cannot on its own lead to the favourable combination of high density, required to give translucency, with little sagging, that will allow wares to be fired without significant distortion. It was found by trail and error that use of finer particles reduced the sagging occurring in the densification heat treatment and enhanced densification. This finding allowed the body to be designed so that it densified without sagging excessively. After establishing this important result, an iterative approach was employed to produce a ware that was very white, translucent, had the required thermal expansion coefficient for glaze fitting, shrank acceptably during the first firing and did not sag during the second firing that stimulated glost firing. The finding on sagging was applied to an anorthite/mullite porcelain body that was under development. This body was also made with a low-clay content and the same prefired body. This whitware has potential to replace bone china and hard porcelain for use in the servere service conditions of hotels and restaurants. It has a higher fracture toughness than hard porcelain but has the same scratch resistant glaze and is more resistant to thermal shock. The sagging of the anorthite/mullite porcelain was substantially reduced while the body was densified. This was achieved by using a combination of finer particles and a reduction in the liquid-phase content that developed during firing.