Dans ce travail, on s'intéresse à la modélisation, l'identification et la commande de systèmes soumis à des frottements secs. L'exposé est divisé en 4 parties. La première partie porte sur la modélisation de systèmes mécaniques complexes et propose un état de l'art des modèles de frottements présents dans la littérature. La deuxième partie est dédiée à la modélisation hybride de systèmes soumis à des frottements secs. Basé sur un nouveau modèle générique, trois modèles, de complexité croissance, sont proposés. La troisième partie traite de l'identification pratique des frottements secs. Des méthodes robustes aux bruits de quantification entachant les données sources sont obtenues. La quatrième partie propose deux synthèses de commande, une commande non-linéaire et une commande robuste synthétisée à partir d'un modèle LPV. L'estimation des frottements secs est abordée dans la dernière partie à l'aide d'observateurs switchés à temps discret. Le modèle et les commandes proposés sont validés sur un banc d'essai d'un embrayage robotisé.

Recent corporate scandals and subsequent regulatory actions have heightened both the academic communities and the public's interest in corporate governance issues. Academics have long argued that voting rights constitute a critical component of a system of corporate governance. We provide evidence on the importance of one aspect of the firm's corporate governance system, namely shareholders' voting rights, by examining the determinants of the decision to grant equity-based compensation to the employees of the firm with or without shareholder approval. We find that poorly-performing firms and poorly-governed firms are more likely to adopt equity-based compensation plans without shareholder approval. Furthermore, when we examine financial performance subsequent to adoption of equity-based compensation plans, we find that poorly-governed firms that adopt equity-based compensation plans without consulting shareholder do not appear to gain any significant benefits associated with the incentives the plans are supposed to provide. In fact, in the year after an equity-based compensation plan is adopted, these firms perform worse than firms that have good systems of corporate governance or firms that place equity-based compensation plans to a shareholder vote. Overall, our results suggest that shareholder voting rights are an important tool of corporate governa

Background: With an increased global market, where companies seek capital abroad, the demand for a more uniform accounting standard has been raised. This uniform accounting standard is not yet available, differences between accounting standards still exists. Several Swedish companies seek risk capital in the USA and some are part of a concern that is listed on the American stock exchange. This means that the Securities and Exchange Commission requires the companies to do a reconciliation to US GAAP on those items that are considered material. This can be an extensive work for the companies if the knowledge about the differences between Swedish GAAP and US GAAP does not exist. Purpose: The purpose with this essay is to describe Swedish GAAP and US GAAP and experienced differences between them, and identify items that should be taken into consideration at a reconciliation. Further we have the purpose to examine the meaning of the expression material and how that affects what items that are chosen for reconciliation, and to create a model for analysis of what items are material. Accomplishment: We have done a research among an assortment of Swedish companies that do a reconciliation of their reports to US GAAP. The purpose of the research have been to identify differences between Swedish GAAP and US GAAP and which ones that are considered material and therefore should be reconciled. We have then described the identified differences and what effect those differences have from the view of a case company. The case company is Sydkraft ÖstVärme that are part of a German group that are listed on the American stock exchange and therefore are affected by US GAAP accounting. Results: Through the information from the research we have created a guideline that could be used as help when doing reconciliation. This guideline consists partly of a model of how an analysis of material items could function when choosing reconciliation items and partly of a compilation of the differences that have been identified and how they should be treated.

Durante l’episcopato del Cardinal Ferrari (1894-1921) gli oratori ambrosiani vissero un periodo di particolare vivacità. Il loro incremento quantitativo, infatti, fu accompagnato da una riforma organizzativa e pedagogica, che intendeva rispondere ai nuovi bisogni formativi emergenti dal processo di industrializzazione e modernizzazione del tessuto sociale milanese. Lo Statuto arcivescovile del 1904 esprimeva una sintesi armonica tra la tradizione catechistico-formativa di ascendenza borromaica e le esigenze di ammodernamento della pastorale giovanile, non senza dialogare con la cultura oratoriana promossa a livello nazionale dai filippini e dai salesiani. Gli oratori ambrosiani delinearono un ampio progetto di educazione popolare, che comprendeva la formazione religiosa, morale, patriottica e fisico-igienica del giovane, e assunsero nella loro prassi nuovi strumenti formativi come la ginnastica, il cinematografo, il teatro e alcune iniziative economico-assistenziali, che affiancarono le già consolidate attività della Dottrina e della ricreazione. Nell’alveo di una progettualità pedagogica sostanzialmente ancorata a modelli educativi tradizionali, ma aperta sul piano pratico al portato della modernità, il movimento oratoriano milanese incarnò un’esperienza di pastorale giovanile coerente con la cultura popolare cattolica coeva e destinata a segnare in modo esemplare la storia dell’attenzione educativa della Chiesa alle giovani generazioni. / Cardinal Ferrari’s episcopate (1894-1921) was an age of unknown liveliness for Milan parish youth clubs. It was marked by an educational and organisational transformation whose purpose was to meet the growing upbringing needs coming from the process of industrialization and modernisation which was affecting Milan society. The Archiepiscopal Chart drawn in 1904 came into being as a successful synthesis of the traditional Archbishop Borromeo’s approach to youth pastoral centred upon catechesis and the pressing need to update, while interacting with the national youth education scholarship promoted by the Salesians of Don Bosco and that of the Oratory by Filippo Neri. Milan parish youth clubs drew up a wide-ranging project of popular education which included religious, moral, patriotic and even physical-hygienic upbringing targets for the young, to be carried out by innovative resources such as physical education, cinema, acting-out, as well as up-to-date charitable opportunities which were backed up by the well-established everlasting activities of catechism and game time. Despite being embedded into a planning process shaped by traditionally imprinted educational models but also oriented to innovation, the Milan parish-youth-club movement epitomised a type of youth pastoral which would mark definitely the history of the youth educational-oriented approach of the Church.

The objective of this work is to determine the effect of four process variables on the properties of blends composed of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) polymers which are compounded using a large scale commercial extruder. The four variables studied are blend composition, specific energy consumption, residence time and shear rate. The last three factors were varied using the extruder screw speed and feed rate. The PC/PBT blends, commercially known as XENOY, were compounded using a WP ZSK 58 mm co-rotating twin screw extruder at the facility of SABIC Innovative Plastics in Cobourg Ontario. The extruder was instrumented to measure online the die pressure, specific energy consumption and blend temperature. The blends were characterized using differential scanning calorimetry, (DSC), scanning electron microscopy, (SEM), gel permeation chromatography, (GPC), and melt volume flow rate, (MVR). After processing, the blend properties determined were melting temperature, glass transition temperature, crystallinity, amorphous phase weight fraction, amorphous phase composition, phase morphology, PBT-rich-phase size, blend molecular weight distribution, and MVR. Using principles available in the literature, a linear regression model was developed to relate the process variables with the online measured properties and output blend properties. Fitting this model allowed the relative importance of each process variable to be estimated for each property. An attempt was also made to identify the general type of PC/PBT blend studied and how it compares with published PC/PBT blend data. It was found that the blends studied were well stabilized since there was no evidence of significant co-polymer formation during processing. Small decreases in molecular weight were attributed to mechanical degradation. Blending increased the crystallization and melting temperatures, as well as blend crystallinity. No practically significant difference in melting temperatures was observed between the different processing conditions. Analysis of glass transitions indicated that the blend components were partially miscible. The amorphous phase compositions were unaffected by blend composition or processing; however, the weight fraction PC-rich-phase present in the blend was strongly influenced by the screw speed. The phase structure of as-extruded blends could not be resolved using the SEM. Therefore, the blends were annealed to coarsen the phases. After annealing, a continuous PC-rich-phase and a discrete PBT-rich-phase were observed. The PBT phase size increased with increasing PBT content. No other statistically significant effects on phase size were observed but this is not conclusive due to the large scatter in the measurements. MVR was primarily influenced by blend composition and specific energy consumption, with the effects of composition being dominant. Further study using higher imaging resolution is required if the phase structures of as received blend pellets are to be characterized. Contrary to current practice, it is recommended that the Utracki-Jukes equation be used rather than the Fox equation for determining amorphous phase composition from glass transition data in PC/PBT blends.

The objective of this work is to determine the effect of four process variables on the properties of blends composed of bisphenol-A polycarbonate (PC) and poly (butylene terephthalate) (PBT) polymers which are compounded using a large scale commercial extruder. The four variables studied are blend composition, specific energy consumption, residence time and shear rate. The last three factors were varied using the extruder screw speed and feed rate. The PC/PBT blends, commercially known as XENOY, were compounded using a WP ZSK 58 mm co-rotating twin screw extruder at the facility of SABIC Innovative Plastics in Cobourg Ontario. The extruder was instrumented to measure online the die pressure, specific energy consumption and blend temperature. The blends were characterized using differential scanning calorimetry, (DSC), scanning electron microscopy, (SEM), gel permeation chromatography, (GPC), and melt volume flow rate, (MVR). After processing, the blend properties determined were melting temperature, glass transition temperature, crystallinity, amorphous phase weight fraction, amorphous phase composition, phase morphology, PBT-rich-phase size, blend molecular weight distribution, and MVR. Using principles available in the literature, a linear regression model was developed to relate the process variables with the online measured properties and output blend properties. Fitting this model allowed the relative importance of each process variable to be estimated for each property. An attempt was also made to identify the general type of PC/PBT blend studied and how it compares with published PC/PBT blend data. It was found that the blends studied were well stabilized since there was no evidence of significant co-polymer formation during processing. Small decreases in molecular weight were attributed to mechanical degradation. Blending increased the crystallization and melting temperatures, as well as blend crystallinity. No practically significant difference in melting temperatures was observed between the different processing conditions. Analysis of glass transitions indicated that the blend components were partially miscible. The amorphous phase compositions were unaffected by blend composition or processing; however, the weight fraction PC-rich-phase present in the blend was strongly influenced by the screw speed. The phase structure of as-extruded blends could not be resolved using the SEM. Therefore, the blends were annealed to coarsen the phases. After annealing, a continuous PC-rich-phase and a discrete PBT-rich-phase were observed. The PBT phase size increased with increasing PBT content. No other statistically significant effects on phase size were observed but this is not conclusive due to the large scatter in the measurements. MVR was primarily influenced by blend composition and specific energy consumption, with the effects of composition being dominant. Further study using higher imaging resolution is required if the phase structures of as received blend pellets are to be characterized. Contrary to current practice, it is recommended that the Utracki-Jukes equation be used rather than the Fox equation for determining amorphous phase composition from glass transition data in PC/PBT blends.

<p>Background: With an increased global market, where companies seek capital abroad, the demand for a more uniform accounting standard has been raised. This uniform accounting standard is not yet available, differences between accounting standards still exists. Several Swedish companies seek risk capital in the USA and some are part of a concern that is listed on the American stock exchange. This means that the Securities and Exchange Commission requires the companies to do a reconciliation to US GAAP on those items that are considered material. This can be an extensive work for the companies if the knowledge about the differences between Swedish GAAP and US GAAP does not exist. </p><p>Purpose: The purpose with this essay is to describe Swedish GAAP and US GAAP and experienced differences between them, and identify items that should be taken into consideration at a reconciliation. Further we have the purpose to examine the meaning of the expression material and how that affects what items that are chosen for reconciliation, and to create a model for analysis of what items are material. </p><p>Accomplishment: We have done a research among an assortment of Swedish companies that do a reconciliation of their reports to US GAAP. The purpose of the research have been to identify differences between Swedish GAAP and US GAAP and which ones that are considered material and therefore should be reconciled. We have then described the identified differences and what effect those differences have from the view of a case company. The case company is Sydkraft ÖstVärme that are part of a German group that are listed on the American stock exchange and therefore are affected by US GAAP accounting. </p><p>Results: Through the information from the research we have created a guideline that could be used as help when doing reconciliation. This guideline consists partly of a model of how an analysis of material items could function when choosing reconciliation items and partly of a compilation of the differences that have been identified and how they should be treated.</p>

A lot has changed since that day on December 17, 1903 when the Wright brothers made the first powered manned flight. Even though the concepts behind flying are unaltered, appearance of stat-of-the-art modern aircrafts has undergone a massive evolution. This is mainly owed to our deeper understanding of how to harness and optimize the interaction between fluid flows and aircraft bodies. Flow passing over wings and different junctions on an aircraft faces numerous local features, for instance, acceleration or deceleration, laminar or turbulent state, and interacting boundary layers. In our study we aim to characterize some of these flow features and their physical roles. Primarily, stability characteristics of flow over a wing subject to a negative pressure gradient are studied. This is a common condition for flows over swept wings. Part of the current numerical study conforms to existing experimental studies where a passive control mechanism has been tested to delay laminarturbulent transition. The same flow type has also been considered to study the receptivity of three-dimensional boundary layers to freestream turbulence. The work entails investigation of effects of low-level freestream turbulence on crossflow instability, as well as interaction with micron-sized surface roughness elements. Another common three-dimensional flow feature arises as a resultof stream-lines passing through a junction, the so-calledcorner-flow. For instance, thisflow can be formed in the junction between the wing and fuselage on aplane.A series of direct numerical simulations using linear Navier-Stokes equationshave been performed to determine the optimal initial perturbation. Optimalrefers to perturbations which can gain the maximum energy from the flow overa period of time. In other words this method seeks to determine theworst-casescenario in terms of perturbation growth. Here, power-iterationtechnique hasbeen applied to the Navier-Stokes equations and their adjoint to determine theoptimal initial perturbation. Recent advances in super-computers have enabled advance computational methods to increasingly contribute to design of aircrafts, in particular for turbulent flows with regions of separation. In this work we investigate theturbulentflow on an infinite wing at a moderate chord Reynolds number of Re= 400,000 using a well resolved direct numerical simulation. A conventional NACA4412 has been chosen for this work. The turbulent flow is characterizedusing statistical analysis and following time history data in regions with interesting flow features. In the later part of this work, direct numerical simulation has been chosen as a tool to mainly investigate the effect of freestream turbulence on the transition mechanism of flow from laminar to turbulent around a turbine blade. / <p>QC 20151125</p>

La fatigue à nombre de cycles élevé (HCF) est un mode de défaillance courant et dangereux pour les aubages de turbomachines. Elle est induite par les efforts dynamiques élevés générés lors de résonances présentes dans la plage de fonctionnement de ces machines. Les dispositifs amortisseurs basés sur l'utilisation du frottement sec, tels que les nageoires ou les frotteurs sous-plateformes, permettent de réduire les amplitudes vibratoires, voire de repousser les fréquences de résonance hors des zones de fonctionnement. Cependant la conception de ces dispositifs reste encore largement basée sur l'empirisme et ils peuvent être la source d'un effet de désaccordage potentiellement nuisible. L'objectif ici est de développer des modélisations adaptées au traitement du problème de vibration des aubages en présence de frottement sec, ceci afin de mieux maîtriser les comportements physiques mis en jeu et donc, de mieux maîtriser leur processus de conception. Plusieurs modélisations numériques sont testées et confrontées à des résultats de référence. Une comparaison entre procédures de résolution temporelle et fréquentielle est menée et montre l'efficacité des méthodes fréquentielles. La méthode fréquentielle de la balance harmonique à plusieurs harmoniques est adaptée au problème et exploitée dans le cadre d'une étude énergétique. Cette étude conduit à une meilleure compréhension des phénomènes mis en jeu lors de l'aplatissement des pics en fonctionnement ; elle permet de démontrer que l'alternance des états de contact glissant et bloqué est à l'origine de cet aplatissement et non la dissipation d'énergie comme souvent avancé dans la littérature. Enfin, la méthode est exploitée pour décrire le comportement des disques aubés désaccordés. La méthode de Monte Carlo est utilisée pour obtenir les caractéristiques statistiques de la réponse forcée d'un système discret, en tenant compte des variations stochastiques des paramètres du contact notamment, la charge normale, la raideur du contact et le coefficient de frottement. Les résultats obtenus permettent de mieux comprendre les effets de la nature variable de ces paramètres fondamentaux sur la dynamique d'ensemble du système non linéaire.

No description available.