266 research outputs found

    Automotive Three-Way Catalyst Diagnostics with Experimental Results

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    Presented is the model based diagnostics of a three-way catalyst (TWC). The proposed TWC model relates measurable engine inputs (engine air mass (AM) and catalyst temperature) to a metric that quantifies TWC oxygen storage capacity. The TWC model structure is based on the dynamics of the TWC and identified using orthogonal least squares (OLS). The model coefficients are estimated using an instrumental variables four step (IV4) approach. TWC diagnostics is realized by means of an information synthesis (IS) technique where changes in the adapted TWC model coefficients are utilized to estimate TWC health. The approach is experimentally validated on a federal test procedure (FTP) drive cycle for healthy (full useful life, FUL) and failed (threshold) TWCs. The results will show that a 100% accurate classification in TWC health estimation (FUL or threshold) is produced for the catalysts tested

    The sport value framework - a new fundamental logic for analyses in sport management

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    Research question: Sports economic theory and management models have frequently been criticised for not sufficiently explaining phenomena in sport management. This article addresses this gap by proposing a conceptual framework that can be used to understand sport management problems and derive appropriate strategies. Research methods: The framework proposed in this conceptual article has been developed through a critical review of existing literature on sport management and theoretical considerations based on the service-dominant logic. Results and findings: The sport value framework (SVF) provides 10 foundational premises on value co-creation in sport management and suggests three levels for its analysis. The main contribution is a new and better theoretical basis for explaining phenomena in sport management compared with traditional sport economic thinking. Moreover, the SVF provides guidance in structuring research in sport management. Implications: The framework encourages researchers and practitioners to rethink their strategies by applying a different logic that captures the complexity of sport management. © 2014 © 2014 European Association for Sport Management

    Increased Infarct Wall Thickness by a Bio-Inert Material Is Insufficient to Prevent Negative Left Ventricular Remodeling after Myocardial Infarction

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    Several injectable materials have been shown to preserve or improve cardiac function as well as prevent or slow left ventricular (LV) remodeling post-myocardial infarction (MI). However, it is unclear as to whether it is the structural support or the bioactivity of these polymers that lead to beneficial effects. Herein, we examine how passive structural enhancement of the LV wall by an increase in wall thickness affects cardiac function post-MI using a bio-inert, non-degradable synthetic polymer in an effort to better understand the mechanisms by which injectable materials affect LV remodeling.Poly(ethylene glycol) (PEG) gels of storage modulus G' = 0.5±0.1 kPa were injected and polymerized in situ one week after total occlusion of the left coronary artery in female Sprague Dawley rats. The animals were imaged using magnetic resonance imaging (MRI) at 7±1 day(s) post-MI as a baseline and again post-injection 49±4 days after MI. Infarct wall thickness was statistically increased in PEG gel injected vs. control animals (p<0.01). However, animals in the polymer and control groups showed decreases in cardiac function in terms of end diastolic volume, end systolic volume and ejection fraction compared to baseline (p<0.01). The cellular response to injection was also similar in both groups.The results of this study demonstrate that passive structural reinforcement alone was insufficient to prevent post-MI remodeling, suggesting that bioactivity and/or cell infiltration due to degradation of injectable materials are likely playing a key role in the preservation of cardiac function, thus providing a deeper understanding of the influencing properties of biomaterials necessary to prevent post-MI negative remodeling

    Delivery modulation in silica mesoporous supports via alkyl chain pore outlet decoration

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    This article focuses on the study of the release rate in a family of modified silica mesoporous supports. A collection of solids containing ethyl, butyl, hexyl, octyl, decyl, octadecyl, docosyl, and triacontyl groups anchored on the pore outlets of mesoporous MCM-41 has been prepared and characterized. Controlled release from pore voids has been studied through the delivery of the dye complex tris(2,2¿-bipyridyl)ruthenium(II). Delivery rates were found to be dependent on the alkyl chain length anchored on the pore outlets of the mesoporous scaffolding. Moreover, release rates follow a Higuchi diffusion model, and Higuchi constants for the different hybrid solids have been calculated. A decrease of the Higuchi constants was observed as the alkyl chain used to tune the release profile is longer, confirming the effect that the different alkyl chains anchored into the pore mouths exerted on the delivery of the cargo. Furthermore, to better understand the relation between pore outlets decoration and release rate, studies using molecular dynamics simulations employing force-field methods have been carried out. A good agreement between the calculations and the experimental observations was observed.Financial support from the Spanish Government (projects MAT2009-14564-C04-01 and MAT2009-14564-C04-04) and the Generalitat Valencia (project PROMETEO/2009/016) is gratefully acknowledged.Aznar Gimeno, E.; Sancenón Galarza, F.; Marcos Martínez, MD.; Martínez Mañez, R.; Stroeve, P.; Cano, J.; Amoros Del Toro, P. (2012). Delivery modulation in silica mesoporous supports via alkyl chain pore outlet decoration. Langmuir. 28:2986-2996. https://doi.org/10.1021/la204438jS298629962
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