871 resultados para Automotive crash simulations
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Finance from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics
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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and Economics
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Increasingly stringed regulations for diesel engine emissions have a significant impact on the required efficiency of DOC. Lowered DOC oxidation efficiency due to thermal aging effects influences the efficiency of the exhaust aftertreatment systems downstream of the DOC. In this work carried out in the Jean Le Rond d’Alembert Institute the effect of hydrothermal aging on the reactivity and structure of a commercial DOC was investigated. The characterization of the catalytic performance was carried out on a synthetic gas bench using carrots catalyst under conditions close to the realistic conditions i.e. using a synthetic gas mixture, representative of the exhaust gases from diesel engines. Different structural characterization techniques were performed: textural and morphological proprieties were analyzed by BET and TEM, the characterization of the presented crystallographic phases was performed by DRX and the determination of the number of reducible species was possible by TPR. TEM results shown, an increase of the metal particle size with the aging caused by the agglomeration of metal particles, revealing the presence of metal sintering. DRX results also suggest the presence of support sintering. Furthermore, DRX and BET results unexpectedly reveal that the most drastic aging conditions used actually activated the catalyst surface. As expected, the aging affected negatively the catalyst performance on the oxidation of methane and CO, however an improvement of the NO oxidation performance with the aging was observed. Nevertheless, for the aging conditions used, catalytic activity results show that the influence of aging in DOC performance was not significant, and therefore, more drastic aging conditions must be used.
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The purpose of this paper is to conduct a methodical drawback analysis of a financial supplier risk management approach which is currently implemented in the automotive industry. Based on identified methodical flaws, the risk assessment model is further developed by introducing a malus system which incorporates hidden risks into the model and by revising the derivation of the most central risk measure in the current model. Both methodical changes lead to significant enhancements in terms of risk assessment accuracy, supplier identification and workload efficiency.
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In traumatic financial times, both shareholders and the media promptly blame companies for lack of decent corporate governance mechanisms. Proxy statement proposals have increasingly been used by the more active shareholders as to vindicate managers to correct anomalies and restore financial markets’ confidence. I examine the proposals of the largest companies in the S&P 500 index after the Lehmann Brothers crash and their effect on stock prices. Proposals initiated by shareholders negatively impact the company’s stock price, particularly if the proposers are unions, pension funds and institutional investors. Also, I find corporate governance proposals to harm firm’s market performance, unlike compensation and social policy proposals whose effects are intangible. The exception to these disappointing attempts to improve companies’ conduct relies on proposals shared by several investors.
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We examine whether earnings manipulation around seasoned equity offerings (SEOs) is associated with an increase in the likelihood of a stock price crash post-issue and test whether the enactment of securities regulations attenuate the relation between SEOs and crash risk. Empirical evidence documents that managerial tendency to conceal bad news increases the likelihood of a stock price crash (Jin and Myers, 2006; Hutton, Marcus, and Tehranian, 2009). We test this hypothesis using a sample of firms from 29 EU countries that enacted the Market Abuse Directive (MAD). Consistent with our hypothesis, we find that equity issuers that engage in earnings management experience a significant increase in crash risk post-SEO relative to control groups of non-issuers; this effect is stronger for equity issuers with poor information environments. In addition, our findings show a significant decline in crash risk post-issue after the enactment of MAD that is stronger for firms that actively manage earnings. This decline in post-issue crash risk is more effective in countries with high ex-ante institutional quality and enforcement. These results suggest that the implementation of MAD helps to mitigate managers’ ability to manipulate earnings around SEOs.
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An exterior body panel solution containing a polydicyclopentadiene skin attached to an interior metallic reinforcement through adhesive bonding is being studied to be applied in the MobiCar bonnet. With this solution is expected to achieve lightness, adequate structural integrity and cost-efficiency. However, there is uncertainty regarding to the bonnet adhesiveness since different metallic materials and adhesive types are being considered for its development. Thus, in this paper, several samples are tested through shear loading with the aim of understanding the loading magnitude expected by using polydicyclopentadiene, steel DC04+ZE and aluminum alloy AW5754-H111 as substrates adhesively bonded by an epoxy or a methacrylate. Methacrylate adhesive have shown greater shear strength in all types of adhesive joints. PDCPD joints presented the highest displacements. Surface degradation was considered adequate over abrading once none strength difference was seen between the different surface treatments. Steel treated by cataphoresis has shown the highest joint interface strength.
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This review deals with the recent developments and present status of the theoretical models for the simulation of the performance of lithium ion batteries. Preceded by a description of the main materials used for each of the components of a battery -anode, cathode and separator- and how material characteristics affect battery performance, a description of the main theoretical models describing the operation and performance of a battery are presented. The influence of the most relevant parameters of the models, such as boundary conditions, geometry and material characteristics are discussed. Finally, suggestions for future work are proposed.
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Dissertação de mestrado em Engenharia Industrial
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Dissertação de mestrado integrado em Engenharia e Gestão Industrial
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Dissertação de mestrado integrado em Engenharia Mecânica
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Dissertação de mestrado integrado em Engenharia Mecânica