published_or_final_version / abstract / toc / Civil Engineering / Master / Master of Philosophy

Nitrogen-selective Carbon Molecular Sieve (CMS) membranes were developed for nitrogen/methane separation. Effects of pyrolysis conditions including pyrolysis temperature protocol and pyrolysis atmosphere were studied for Matrimid® and 6FDA:BPDA-DAM precursors. It was revealed that high pyrolysis temperature is essential to achieve attractive nitrogen/methane selectivity due to the subtle size difference between the two gas penetrants. Detailed study on one of the best performing CMS membranes showed that diffusion selection, more specifically, the entropic factor responsible for diffusion selection provides a significant contribution to the high selectivity. The effect of precursor was studied by considering nine carefully selected polymers. The structures and properties of these polymer precursors were compared and correlated with the separation performance of resulting CMS membranes. The translation of intrinsic CMS transport properties into the hollow fiber morphology was also explored. Substructure collapse and asymmetry lost during pyrolysis were observed, which resulted in significant increases of separation layer thickness and decreases in permeance. Vinyltrimethoxy silane (VTMS)-treatment was applied to polymer hollow fiber before pyrolysis to overcome the problem of substructure collapse. The effects of VTMS-treatment on both the substructure and skin layer are discussed.

This research examines the relationship between courts and legislatures in a comparative perspective. Specifically, I examine how 1) the ideological composition of the bench; 2) the propensity of court involvement in a given policy area; 3) the disposition of court decisions in a given policy area; and 4) judicial institutional rules shape judicial-legislative relations and subsequently influence bill introductions and policy enactments by state legislatures. By examining HMO regulation and education policy in the American states during the 1990s, I find evidence that judicial influence does impact legislative policymaking, in both introduction and enactment stage, across both policy areas. Education policy demonstrates a stronger judicial impact than HMO regulation. While traditional scholarship has depicted the judicial branch as having minimal impact on policy formation, and subsequently social change, the findings of this study suggest that we have overlooked an important policymaking role of the judicial branch. Furthermore, state policy research has not given adequate attention to judicial influence as an explanation for policy formation in the American states.

Syftet med vår uppsats var att vi ville, genom intervjuer med familjehemsföräldrar och socialsekreterare, få kunskap om och djupare förståelse för små barn som lever i familjehem. Våra frågeställningar blev därmed: Vilka erfarenheter har familjehemsföräldrar/socialsekreterare av små barn som placeras? Vid ett omhändertagande, hur kan man bibehålla relationen mellan barn och biologiska föräldrar och vilka möjligheter har barn att knyta an till familjehemsföräldrar? Hur skiljer sig en placering som är frivillig från en tvångsplacering? Vilka erfarenheter har familjehemsföräldrar/socialsekreterare angående barns återförening till biologiska föräldrar? Resultatet från intervjuerna visade på att såväl familjehemsföräldrar som socialsekreterare upplever svårigheter vid placering av små barn och att man bäst bevarar relationen mellan biologiska föräldrar och barn genom kontinuerliga umgängen. Familjehemsföräldrar har inte upplevt några svårigheter för barnet att knyta an till dem och de har skilda erfarenheter av vilken form av placering som är mest gynnsam för barnet. Både familjehemsföräldrar och socialsekreterare framför att målet är att barnet ska återförenas med ursprungsfamiljen, men de kan se svårigheter när barnet känner tillhörighet i familjehemmet.

When launching a satellite a separation system is used to keep the satellite attached to a launch vehicle during ascent and to separate it from the launch vehicle while in space. In separation analysis the separation is studied by simulations to see if requirements on the system can be fulfilled. The purpose of this master’s thesis is to investigate if separation analysis can be done using the modeling program OpenModelica and to evaluate OpenModelica and compare it to other modeling programs. OpenModelica is free software implementing the Modelica language, which is an object-oriented language for modeling and simulation of complex physical systems. Modelica uses equation-based modeling, this means that the physical behaviour of a model is described by differential, algebraic and discrete equations and no particular variable needs to be solved manually. The work is divided into two parts. The main part is to implement a mathematical model of a separation system in OpenModelica, simulate it and study the behaviour of the system. A Monte Carlo method, which randomly generates values for uncertain model parameters, is used when simulating the model. The other part of the work is to evaluate OpenModelica and compare it with other modeling programs, such as Matlab/Simulink, C/C++ and JAVA to see advantages and disadvantages with OpenModelica.

My essay is about a dilemma that came up on a preschool that I worked in. My purpose with my essay is to examine and to get an understanding for what children with attachement and separation anxiety goes through, and how a preschool teacher the best way can help them. The background story is about a boy named Sixten (not his real name). When separated from one of the preschool teachers Sixten exhibits a great deal of separation anxiety. In the story I give some clear examples of situations where Sixten displays this separation anxiety. I have in the essay viewed it from different perspectives and I have questioned my own role as an educator, but also my entire team. I have the whole time analyzed my own and my colleagues actions to be able to find out where the dilemma really is. I have gained new knowledge through the study of academic literature and my own analysis of the situations with separation anxiety. I have also learned how to use that knowledge in my work as a preschool teacher.

Electrophoresis separation corresponds to the motion and separation of dispersed particles under the influence of a constant electric field. In molecular biology, electrophoresis separation plays a major role in identifying, quantifying and studying different biological samples such as proteins, peptides, RNA acids, and DNA. In electrophoresis separation, different characteristics of particles, such as charge to mass ratio, size, and pI, can be used to separate and isolate those particles. For very complex samples, two or more characteristics can be combined to form a multi-dimensional electrophoresis separation system, significantly improving separation efficiency. Much effort has been devoted in recent years to performing electrophoresis separations in microfluidic format. Employing microfluidic technology for this purpose provides several benefits, such as improved transport control, reduced sample volumes, simplicity of operation, portability, greater accessibility, and reduced cost. The aim of this study is to develop microfluidic systems for high-performance separation of biochemical samples using electrophoresis methods. The first part of the thesis concerns the development of a fully integrated microfluidic chip for isoelectric focusing separation of proteins with whole-channel imaging detection. All the challenges posed in fabricating and integrating the chip were addressed. The chip was tested by performing protein and pI marker separations, and the separation results obtained from the chip were compared with those obtained from commercial cartridges. Side-by-side comparison of the results validated the developed chip and fabrication techniques. The research also focuses on improving the peak capacity and separation resolution of two counter-flow gradient electrofocusing methods: Temperature Gradient Focusing (TGF) and Micellar Affinity Gradient Focusing (MAGF). In these techniques, a temperature gradient across a microchannel or capillary is used to separate analytes. With an appropriate buffer, the temperature gradient creates a gradient in the electrophoretic velocity (TGF) or affinity (MAGF) of analytes and, if combined with a bulk counter-flow, ionic species concentrate at unique points where their total velocity is zero, and separate from each other. A bilinear temperature gradient is used along the separation channel to improve both peak capacity and separation resolution simultaneously. The temperature profile along the channel consists of a very sharp gradient used to pre-concentrate the sample, followed by a shallow gradient that increases separation resolution. A simple numerical model was applied to predict the improvement in resolution when using a bilinear gradient. A hybrid PDMS/glass chip integrated with planar micro-heaters for generating bilinear temperature gradients was fabricated using conventional sputtering and soft lithography techniques. A specialized design was developed for the heaters to achieve the desired bilinear profiles using both analytical and numerical modeling. To confirm the temperature profile along the channel, a two-color thermometry technique was also developed for measuring the temperature inside the chip. Separation performance was characterized by separating several different dyes, amino acids and peptides. Experiments showed a dramatic improvement in peak capacity and resolution of both techniques over the standard linear temperature gradients. Next, an analytical model was developed to investigate the effect of bilinear gradients in counter-flow gradient electrofocusing methods. The model provides a general equation for calculating the resolution for different gradients, diffusion coefficients and bulk flow scan rates. The results indicate that a bilinear gradient provides up to 100% improvement in separation resolution over the linear case. Additionally, for some scanning rates, an optimum bilinear gradient can be found that maximizes separation resolution. Numerical modeling was also developed to validate some of the results. The final part of the thesis describes the development of a two-dimensional separation system for protein separation, combining temperature gradient focusing (TGF) and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) in a PDMS/glass microfluidic chip. An experimental study was performed on separating a mixture of proteins using two characteristics: charge to mass ratio, and size. Experimental results showed a dramatic improvement in peak capacity over each of the one-dimensional separation techniques.

Olefin/Paraffin separation, traditionally carried out by cryogenic distillation, is difficult to achieve due to the similar size and volatility of the components. Recently, many studies have explored membrane separation methods that utilize a metal ion to facilitate preferential olefin transport across the membrane. However, much of this work focuses on smaller molecules, C2-C3, which are gaseous at room temperature, while little work has been done studying separation of larger molecules, C5 and greater, which are generally liquid at room temperature. The processes developed to separate small molecules are not necessarily directly applicable to separate larger molecules. A polymer electrolyte membrane consisting of an active layer of polyethylene oxide (PEO) and silver tetrafluoroborate (AgBF4) has shown high selectivity for separating gaseous olefin/paraffin mixtures. The current project investigates the feasibility of applying this membrane to the separation of pentene and pentane (liquid C5 olefin and paraffin). Process variables investigated are the: pure component permeability ratio, equilibrium sorption uptakes, pure component diffusivities, and stable membrane lifetime. Permeation tests on individual species (n-pentane and 1-pentene) were performed in two operating modes with membranes of varying silver concentrations: direct liquid contact to the membrane, and vapour contact to the membrane. The vapour contact mode showed improved membrane stability in comparison to the liquid contact mode. The olefin/paraffin permeability ratio increases with increasing silver content in the membrane, however, the membrane selectivity is much lower than that achieved with smaller olefin/paraffin pairs. Selective chemical interactions between pentene and the membrane were observed, as the pentene sorption uptake is higher than that of pentane. In addition, a residual fraction is observed – a fraction of the pentene does not desorb from the membrane at ambient conditions – indicating a permanent or semi-permanent interaction. Desorption of pentane is determined to follow a Fickian diffusion model, while desorption of pentene appears to be governed by pseudo-second order kinetics.

Heavy Fuel Oil (HFO) is a petroleum product and emerging contaminant used as fuel by cargo ships, cruise liners, and oil tankers. As a high-frequency, low volume commodity shipped by pipeline, train, truck, and ship, it is at high risk for small-scale spills in terrestrial, aquatic, and marine environments. There are few reports characterizing HFOs and quantifying the contaminants therein, but previous studies have shown that the most toxic classes of compounds in petroleum products are polycyclic aromatic hydrocarbons (PAHs). This project seeks to address that by analyzing HFO 7102, the specific HFO spilled in Wabamun Lake, Alberta in August 2005. Through an Effects-Driven Fractionation and Analysis, HFO 7102 was successively fractionated by physical and chemical means. First, a low-temperature vacuum distillation separated the oil into three fractions by volatility. The most toxic of these (lowest median toxic concentration, or LC50), F3, underwent a series of solvent extractions to remove asphaltenes and waxes. The remaining PAH-rich extract (F3-1) was further separated using open column chromatography into non-polar, mid-polar, and polar fractions with groupings approximately by number of aromatic rings. At each stage, fractions and sub-fractions were characterized by GC-MS for compositional analysis and bioassays were conducted with rainbow trout embryos. In this fashion, toxicity thresholds were developed for all fractions and the components of HFO 7102 associated with toxicity were identified and quantified. The F3 fraction was six times more toxic than the whole oil. While the wax fraction (F3-2) was shown to be non-toxic, the remaining PAH-rich extract (F3-1) accounted for all of the toxicity in F3. Future work may be done to determine the relative toxicity of the last fractions generated and identify a range of PAH responsible for fish toxicity. It is expected that the F3-1-2 fraction will be most toxic, as it contains nearly all of the three-ring and most of the four-ring PAH. These size classes of PAH have been associated with chronic toxicity to fish embryos in studies of crude oil. Further separations may be attempted to identify a more specific range of toxic compounds, such as by degree of alkylation. / Thesis (Master, Chemistry) -- Queen's University, 2012-07-31 11:31:15.238

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