3 research outputs found

    Solid on liquid deposition

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    A process for the deposition of a solid layer onto a liquid is presented. The polymer poly-di-chloro-para-xylylene, also known as Parylene C, was grown on low vapour pressure liquids using the conventional low pressure chemical vapour deposition process. A reactor was built and a process developed to enable the deposition of Parylene C at atmospheric pressure over high vapour pressure liquids. It was used to deposit Parylene C over water among others. In all cases Parylene C encapsulated the liquid without influencing its initial shape. The results presented here show also that the Parylene C properties are not affected by its growth on liquid templates and the roughness of the Parylene C surface in contact with the liquid during the deposition is extremely low

    Development of structural debris flow fragility curves (debris flow buildings resistance) using momentum flux rate as a hazard parameter

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    Societal risks associated with debris flow hazards are significant and likely to escalate due to global population growth trends and the compounding effects of climate change. Quantitative risk assessment methods (QRA) provide a means of anticipating the likely impacts and consequences of settlement in areas susceptible to landslide activity and are increasingly being used to inform land use decisions that seek to increase disaster resilience through mitigation and/or adaptation. Current QRA methods for debris flow hazards are based primarily on empirical vulnerability functions that relate hazard intensity (depth, velocity, etc.) to expected levels of loss for a given asset of concern, i.e. most of current methods are dedicated to loss-intensity relations. Though grounded in observed cause-effect relationships, empirical vulnerability functions are not designed to predict the capacity of a building to withstand the physical impacts of a debris flow event, or the related uncertainties associated with modelling building performance as a function of variable debris flow parameters. This paper describes a methodology for developing functions that relate hazard intensity to probability of structural damage, i.e., fragility functions, rather than vulnerability functions, based on the combined hydrodynamic forces of a debris flow event (hazard level) and the inherent structural resistance of building typologies that are common in rural mountainous settings (building performance). Hazard level includes a hydrodynamic force variable (FDF), which accounts for the combined effects of debris flow depth and velocity, i.e. momentum flux (hv2), material density (?) and related flow characteristics including drag (Cd) and impact coefficient (Kd). Building performance is measured in terms of yield strength (Ay), ultimate lateral capacity (AU) and weight to breadth ratios (W/B) defined for a portfolio building types that are common in mountain settlements. Collectively, these model parameters are combined using probabilistic methods to produce building-specific fragility functions that describe the probability of reaching or exceeding successive thresholds of structural damage over a range of hazard intensity values, expressed in terms of momentum flux. Validation of the proposed fragility model is based on a comparison between model outputs and observed cause-effect relationships for recent debris flow events in South Korea and in Colombia. Debris flow impact momentum fluxes, capable of resulting in complete damage to unreinforced masonry buildings (URM) in those regions are estimated to be on the order of 24 m3/s2, consistent with field-based observations. Results of our study offer additional capabilities for assessing risks associated with urban growth and development in areas exposed to debris flow hazards. © 2018 Elsevier B.V

    Swiss analysis of multiple sclerosis: a multicenter, non-interventional, retrospective cohort study of disease-modifying therapies

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    BACKGROUND: There is a scarcity of reports comparing efficacy and tolerability of the multiple sclerosis (MS) disease-modifying therapies [DMTs; intramuscular interferon-β1a (IM IFNβ-1a), subcutaneous (SC) IFNβ-1a, SC IFNβ-1b, SC glatiramer acetate (GA)] in a real-world setting. METHODS: This multicenter, non-interventional, retrospective cohort study analyzed data from 546 patients with clinically isolated or relapsing-remitting MS constantly treated with one DMT for 2 years. Annualized relapse rate (ARR), Expanded Disability Status Scale (EDSS) scores, and DMT tolerability were assessed. RESULTS: Demographic data were comparable across DMTs. There were no significant differences between DMT groups in ARR during study year 1 (p = 0.277) or study year 2 (p = 0.670), or in EDSS change between years 1 and 2 (p = 0.624). Adverse events were frequent (39-56%) in all groups. Flu-like symptoms were less frequent with GA treatment (2.3% vs. IM IFNβ-1a, 46.7%; SC IFNβ-1a, 39.8%; SC IFNβ-1b, 25.8%; p < 0.05). Injection site reactions were less often reported with IM IFNβ-1a (10.5% vs. SC IFNβ-1a, 33.9%; SC IFNβ-1b, 38.3%; GA, 26.1%; p < 0.05). CONCLUSIONS: All DMTs showed comparable effects on MS relapse rate and EDSS change, with IM IFNβ-1a and GA being more tolerable with respect to injection site reactions and flu-like symptoms, respectively
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