356 research outputs found

    Election Campaign Finance Rules in Canadian Municipalities: An Overview

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    The Money and Local Democracy Project explores the effects of campaign finance rules on municipal election campaigns and election outcomes in Canada. Governments around the world regulate election campaign financing to ensure that elections are fair and competitive, although they do so in different ways. Funded by a Western University Undergraduate Student Research Internship (UWO) grant, research assistant Brittany Bouteiller was tasked with conducting preliminary research on 65 municipalities across Canada to determine the availability of campaign finance data from local and provincial governments and to identify clusters or trends. This research bulletin summarizes her findings.https://ir.lib.uwo.ca/urbancentre-reports/1006/thumbnail.jp

    Money and Local Democracy: Local Campaign Finance Regimes in Canada

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    Prof. Zack Taylor plans to apply for a major research grant to research the effects of campaign finance regimes. To provide a comprehensive assessment and to lay the groundwork for the grant application, I collected data on 65 municipalities across Canada, which together comprise 50% of the national population, to determine their campaign donation and spending limits, candidate disclosure requirements, and availability of disclosure statements over the last 3 election cycles. As well, I looked at the number of candidates and offices available in each of the municipalities for the last 3 election cycles

    Adhesion and non-linear rheology of adhesives with supramolecular crosslinking points

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    Soft supramolecular materials are promising for the design of innovative and highly tunable adhesives. These materials are composed of polymer chains functionalized by strongly interacting moieties, sometimes called "stickers". In order to systematically investigate the effect of the presence of associative groups on the debonding properties of a supramolecular adhesive, a series of supramolecular model systems has been characterized by probe-tack tests. These model materials, composed of linear and low dispersity poly(butylacrylate) chains functionalized in the middle by a single tri-urea sticker, are able to self-associate by six hydrogen bonds and range in molecular weight (M n) between 5 and 85 kg/mol. The linear rheology and the nanostructure of the same materials (called "PnBA3U") was the object of a previous study 1,2. At room temperature, the association of polymers via hydrogen bonds induces the formation of rod-like aggregates structured into bundles for M n \textless{} 40kg/mol and the behavior of a soft elastic material was observed (G'\textgreater{}\textgreater{}G "and G'~ω\omega 0). For higher M n , the filaments were randomly oriented and polymers displayed a crossover towards viscous behavior although terminal relaxation was not reached in the experimental frequency window. All these materials show however similar adhesive properties characterized by a cohesive mode of failure and low debonding energies (W adh \textless{}40J/m 2 for a debonding speed of 100ÎŒ\mum/s). The debonding mechanisms observed during the adhesion tests have been investigated in detail with an Image tools analysis developed by our group 3. The measure of the projected area covered by cavities growing in the adhesive layer during debonding can be used to estimate the true stress in the walls of the cavities and thus, to characterize the in-situ large strain deformation of the thin layer during the adhesion test itself. This analysis revealed in particular that the PnBA3U materials with M n \textless{} 40 kg/mol soften very markedly at large deformation like yield stress fluids, explaining the low adhesion energies measured for these viscoelastic gels.

    Probabilistic and predictive performance-based approach for assessing reinforced concrete structures lifetime: The applet project

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    International audienceConcrete deterioration results in different damage extents, from cracking to concrete spalling, from losses of reinforcement cross-sections to bond losses. A relevant prediction of this performance is the basis for a successful management of the concrete structures. Conversely, the large amount of uncertainties related to parameters and models require a specific analysis in order to provide relevant results. The APPLET project intends to develop a probabilistic and predictive performance-based approach by quantifying the various sources of variability (material and structure), studying the interaction between environmental aggressive agents and the concrete material, ensuring a transfer of the physical-chemical models at the material scale towards models at the structure level, including and understanding in a better manner the corrosion process, integrating interface models between reinforcement and concrete, proposing relevant numerical models, integrating know-how from monitoring or inspection. To provide answers, a consortium of 19 partners has been established and has promoted a research project funded by the French Research Science Agency (ANR). Started in May 2007, the project has ended in November 2010. This paper will resume the most significant advances targeted by this research project

    Self-assembly in solution of a reversible comb-shaped supramolecular polymer

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    We report a single step synthesis of a polyisobutene with a bis-urea moiety in the middle of the chain. In low polarity solvents, this polymer self-assembles by hydrogen bonding to form a combshaped polymer with a central hydrogen bonded backbone and polyisobutene arms. The comb backbone can be reversibly broken, and consequently, its length can be tuned by changing the solvent, the concentration or the temperature. Moreover, we have proved that the bulkiness of the side-chains have a strong influence on both the self-assembly pattern and the length of the backbone. Finally, the density of arms can be reduced, by simply mixing with a low molar mass bis-urea

    Random, blocky and alternating ordering in supramolecular polymers of chemically bidisperse monomers

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    As a first step to understanding the role of molecular or chemical polydispersity in self-assembly, we put forward a coarse-grained model that describes the spontaneous formation of quasi-linear polymers in solutions containing two self-assembling species. Our theoretical framework is based on a two-component self-assembled Ising model in which the bidispersity is parameterized in terms of the strengths of the binding free energies that depend on the monomer species involved in the pairing interaction. Depending upon the relative values of the binding free energies involved, different morphologies of assemblies that include both components are formed, exhibiting paramagnetic-, ferromagnetic- or anti ferromagnetic-like order,i.e., random, blocky or alternating ordering of the two components in the assemblies. Analyzing the model for the case of ferromagnetic ordering, which is of most practical interest, we find that the transition from conditions of minimal assembly to those characterized by strong polymerization can be described by a critical concentration that depends on the concentration ratio of the two species. Interestingly, the distribution of monomers in the assemblies is different from that in the original distribution, i.e., the ratio of the concentrations of the two components put into the system. The monomers with a smaller binding free energy are more abundant in short assemblies and monomers with a larger binding affinity are more abundant in longer assemblies. Under certain conditions the two components congregate into separate supramolecular polymeric species and in that sense phase separate. We find strong deviations from the expected growth law for supramolecular polymers even for modest amounts of a second component, provided it is chemically sufficiently distinct from the main one.Comment: Submitted to Macromolecules, 6 figures. arXiv admin note: substantial text overlap with arXiv:1111.176

    Correlated Set Coordination in Fault Tolerant Message Logging Protocols

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    Abstract. Based on our current expectation for the exascale systems, composed of hundred of thousands of many-core nodes, the mean time between failures will become small, even under the most optimistic as-sumptions. One of the most scalable checkpoint restart techniques, the message logging approach, is the most challenged when the number of cores per node increases, due to the high overhead of saving the message payload. Fortunately, for two processes on the same node, the failure probability is correlated, meaning that coordinated recovery is free. In this paper, we propose an intermediate approach that uses coordination between correlated processes, but retains the scalability advantage of message logging between independent ones. The algorithm still belongs to the family of event logging protocols, but eliminates the need for costly payload logging between coordinated processes.

    Experimental demonstration of singular-optical colouring of regularly scattered white light

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    Experimental interference modelling of the effects of colouring of a beam traversing a light-scattering medium is presented. It is shown that the result of colouring of the beam at the output of the medium depends on the magnitudes of the phase delays of the singly forward scattered partial signals. The colouring mechanism has for the first time experimentally been illustrated for a forward propagating beam through a light-scattering medium. This is showed in video-fragments of the interferograms recorded within the zero interference fringe with a gradual change of the path difference of the interfering polychromatic wave trains. Spectral investigation of the effects of colouring has been carried out using a solution of liquid crystal in a polymer matrix. The amplitude ratio of the non-scattered and the singly forward scattered interfering components significantly affects the colour intensity. It has further been established that the spectral content of the illuminating beam strongly influences the colour of the resulting radiation
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