112 resultados para Flutter


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This paper considers the ways in which structural model parameter variability can influence aeroelastic stability. Previous work on formulating the stability calculation (with the Euler equations providing the aerodynamic predictions) is exploited to use Monte Carlo, interval, and perturbation calculations to allow this question to be investigated. Three routes are identified. The first involves variable normal-mode frequencies only. The second involves normal-mode frequencies and shapes. Finally, the third, in addition to normal-mode frequencies and shapes, also includes their influence on the static equilibrium. Previous work has suggested only considering the first route, which allows significant gains in computational efficiency if reduced-order models can be built for the aerodynamics. However, results in the current paper show that neglecting the mode-shape variation can give misleading results for the flutter-onset prediction, complicating the development of reduced aerodynamic models for variability analysis.

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his essay is premised on the following: a conspiracy to fix or otherwise manipulate the outcome of a sporting event for profitable purpose. That conspiracy is in turn predicated on the conspirators’ capacity to: (a) ensure that the fix takes place as pre-determined; (b) manipulate the betting markets that surround the sporting event in question; and (c) collect their winnings undetected by either the betting industry’s security systems or the attention of any national regulatory body or law enforcement agency.

Unlike many essays on this topic, this contribution does not focus on the “fix”– part (a) of the above equation. It does not seek to explain how or why a participant or sports official might facilitate a betting scam through either on-field behaviour that manipulates the outcome of a game or by presenting others with privileged inside information in advance of a game. Neither does this contribution seek to give any real insight into the second part of the above equation: how such conspirators manipulate a sports betting market by playing or laying the handicap or in-play or other offered betting odds. In fact, this contribution is not really about the mechanics of sports betting or match fixing at all; rather it is about the sometimes under explained reason why match fixing has reportedly become increasingly attractive as of late to international crime syndicates. That reason relates to the fact that given the traditional liquidity of gambling markets, sports betting can, and has long been, an attractively accessible conduit for criminal syndicates to launder the proceeds of crime. Accordingly, the term “winnings”, noted in part (c) of the above equation, takes on an altogether more nefarious meaning.

This essay’s attempt to review the possible links between match fixing in sport, gambling-related “winnings” and money laundering is presented in four parts.

First, some context will be given to what is meant by money laundering, how it is currently policed internationally and, most importantly, how the growth of online gambling presents a unique set of vulnerabilities and opportunities to launder the proceeds of crime. The globalisation of organised crime, sports betting and transnational financial services now means that money laundering opportunities have moved well beyond a flutter on the horses at your local racetrack or at the roulette table of your nearest casino. The growth of online gambling platforms means that at a click it is possible for the proceeds of crime in one jurisdiction to be placed on a betting market in another jurisdiction with the winnings drawn down and laundered in a third jurisdiction and thus the internationalisation of gambling-related money laundering threatens the integrity of sport globally.

Second, and referring back to the infamous hearings of the US Senate Special Committee to Investigate Organised Crime in Interstate Commerce of the early 1950s, (“the Kefauver Committee”), this article will begin by illustrating the long standing interest of organised crime gangs – in this instance, various Mafia families in the United States – in money laundering via sports gambling-related means.

Third, and using the seminal 2009 report “Money Laundering through the Football Sector” by the Financial Action Task Force (FATF, an inter-governmental body established in 1989 to promote effective implementation of legal, regulatory and operational measures for combating money laundering, terrorist financing and other related threats to the integrity of the international financial system), this essay seeks to assess the vulnerabilities of international sport to match fixing, as motivated in part by the associated secondary criminality of tax evasion and transnational economic crime.

The fourth and concluding parts of the essay spin from problems to possible solutions. The underlying premise here is that heretofore there has been an insularity to the way that sports organisations have both conceptualised and sought to address the match fixing threat e.g., if we (in sport) initiate player education programmes; establish integrity units; enforce codes of conduct and sanctions strictly; then our integrity or brand should be protected. This essay argues that, although these initiatives are important, the source and process of match fixing is beyond sport’s current capacity, as are the possible solutions.

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O presente Projeto Artístico propõe como principal objetivo a divulgação de obras para clarinete solo e para clarinete e eletrónica produzidas no seio das classes de clarinete e composição da Escola Superior de Música de Lisboa. A preparação e montagem da obra de Edward Luiz Ayres d’Abreu, aqui realizada em estreia absoluta, pretende manter viva a continuidade de produção artística desta instituição a todos os níveis, neste caso, entre dois estudantes. Neste relatório estão registados os benefícios alcançados com o trabalho de pesquisa relacionado com os aspectos biográficos dos compositores, o contexto da criação das obras, assim como a análise e apuramento de questões interpretativas pouco utilizadas na música convencional como por exemplo, as técnicas clarinetísticas contemporâneas (glissando, frulato, vibrato, som e voz, multifónicos, micro-tons), a prática de música com eletrónica, ou a experiência inovadora da recriação musical em palco de uma partitura gráfica.

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Introduction : Bien que la pratique de l’usage de la warfarine se soit améliorée au cours de la dernière décennie, aucune recommandation claire basée sur le dosage de l’amiodarone n’a été jusqu’à maintenant standardisée, ce qui représente un grand obstacle pour les cliniciens. La warfarine a un index thérapeutique étroit nécessitant un suivi régulier et un ajustement individuel de la posologie, ceci afin de déterminer la dose thérapeutique, tout en prévenant les effets secondaires qui pourraient être fatals dans certains cas. La variabilité interindividuelle de la réponse à la warfarine dépend de plusieurs facteurs, dont l’âge, le sexe, le poids, l’alimentation et l’interaction médicamenteuse, mais ceux-ci n’expliquent que partiellement les différences de sensibilité à la warfarine. Les polymorphismes des gènes CYP2C9 et VKORC1 jouent un rôle important dans la réponse à la warfarine et expliquent jusqu’à 50% de la variabilité des doses. L’utilisation d’antiarythmiques telle l’amiodarone peut accentuer considérablement l’effet de la warfarine et nécessite généralement une diminution de 30 à 50% de la dose de la warfarine. Aucune étude à ce jour n’a tenté de déterminer l’utilité du génotypage des polymorphismes des gènes CYP2C9 et VKORC1 chez les patients sous traitement combiné de warfarine et amiodarone. Objectif : Notre étude a pour objectif tout d’abord de déterminer si des facteurs génétiques influencent la première dose de stabilisation de la warfarine chez les patients en FA après l’introduction de l’amiodarone. Nous allons également tenter de confirmer l’association préalablement rapportée entre les facteurs génétiques et la première dose de stabilisation de warfarine dans notre population à l’étude. Méthodes : Un devis de cohorte rétrospective de patients qui fréquentaient la clinique d'anticoagulothérapie de l’Institut de cardiologie de Montréal entre le 1er janvier 2007 et le 29 février 2008 pour l’ajustement de leur dose selon les mesures d'INR. Au total, 1615 patients ont été recrutés pour participer à cette étude de recherche. Les critères de sélection des patients étaient les patients avec fibrillation auriculaire ou flutter, ayant un ECG documenté avec l'un de ces deux diagnostics et âgé de moins de 67 ans, en raison d’une moindre comorbidité. Les patients souffrant d’insuffisance hépatique chronique ont été écartés de l’étude. Tous les patients devaient signer un consentement éclairé pour leur participation au projet et échantillon de sang a été pri pour les tests génétiques. La collecte des données a été effectuée à partir du dossier médical du patient de l’Institut de cardiologie de Montréal. Un formulaire de collecte de données a été conçu à cet effet et les données ont ensuite été saisies dans une base de données SQL programmée par un informaticien expert dans ce domaine. La validation des données a été effectuée en plusieurs étapes pour minimiser les erreurs. Les analyses statistiques utilisant des tests de régression ont été effectuées pour déterminer l’association des variants génétiques avec la première dose de warfarine. Résultats : Nous avons identifié une association entre les polymorphismes des gènes CYP2C9 et VKORC1 et la dose de la warfarine. Les polymorphismes génétiques expliquent jusqu’à 42% de la variabilité de dose de la warfarine. Nous avons également démontré que certains polymorphismes génétiques expliquent la réduction de la dose de warfarine lorsque l’amiodarone est ajoutée à la warfarine. Conclusion : Les travaux effectués dans le cadre de ce mémoire ont permis de démontrer l’implication des gènes CYP2C9 et VKORC1 dans la réponse au traitement avec la warfarine et l’amiodarone. Les résultats obtenus permettent d’établir un profil personnalisé pour réduire les risques de toxicité, en permettant un dosage plus précis de la warfarine pour assurer un meilleur suivi des patients. Dans le futur, d’autres polymorphismes génétiques dans ces gènes pourraient être évalués pour optimiser davantage la personnalisation du traitement.

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Die Untersuchung des dynamischen aeroelastischen Stabilitätsverhaltens von Flugzeugen erfordert sehr komplexe Rechenmodelle, welche die wesentlichen elastomechanischen und instationären aerodynamischen Eigenschaften der Konstruktion wiedergeben sollen. Bei der Modellbildung müssen einerseits Vereinfachungen und Idealisierungen im Rahmen der Anwendung der Finite Elemente Methode und der aerodynamischen Theorie vorgenommen werden, deren Auswirkungen auf das Simulationsergebnis zu bewerten sind. Andererseits können die strukturdynamischen Kenngrößen durch den Standschwingungsversuch identifiziert werden, wobei die Ergebnisse Messungenauigkeiten enthalten. Für eine robuste Flatteruntersuchung müssen die identifizierten Unwägbarkeiten in allen Prozessschritten über die Festlegung von unteren und oberen Schranken konservativ ermittelt werden, um für alle Flugzustände eine ausreichende Flatterstabilität sicherzustellen. Zu diesem Zweck wird in der vorliegenden Arbeit ein Rechenverfahren entwickelt, welches die klassische Flatteranalyse mit den Methoden der Fuzzy- und Intervallarithmetik verbindet. Dabei werden die Flatterbewegungsgleichungen als parameterabhängiges nichtlineares Eigenwertproblem formuliert. Die Änderung der komplexen Eigenlösung infolge eines veränderlichen Einflussparameters wird mit der Methode der numerischen Fortsetzung ausgehend von der nominalen Startlösung verfolgt. Ein modifizierter Newton-Iterations-Algorithmus kommt zur Anwendung. Als Ergebnis liegen die berechneten aeroelastischen Dämpfungs- und Frequenzverläufe in Abhängigkeit von der Fluggeschwindigkeit mit Unschärfebändern vor.

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We review and structure some of the mathematical and statistical models that have been developed over the past half century to grapple with theoretical and experimental questions about the stochastic development of aging over the life course. We suggest that the mathematical models are in large part addressing the problem of partitioning the randomness in aging: How does aging vary between individuals, and within an individual over the lifecourse? How much of the variation is inherently related to some qualities of the individual, and how much is entirely random? How much of the randomness is cumulative, and how much is merely short-term flutter? We propose that recent lines of statistical inquiry in survival analysis could usefully grapple with these questions, all the more so if they were more explicitly linked to the relevant mathematical and biological models of aging. To this end, we describe points of contact among the various lines of mathematical and statistical research. We suggest some directions for future work, including the exploration of information-theoretic measures for evaluating components of stochastic models as the basis for analyzing experiments and anchoring theoretical discussions of aging.

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The ring spinning process has been used to produce fine and high quality staple fibre yarns. The stability of the rotating yarn loop (i.e. balloon) between the yarn-guide and the traveller-ring is crucial to the success and economics of this process. Balloon control rings are used to contain the yarn-loop, by reducing the yarn tension and decreasing the balloon flutter instability. Flutter instability here refers to the uncontrolled changes in a ballooning yarn under dynamic forces, including the air drag. Due to the significant variation in the length and radius of the balloon during the bobbin filling process, the optimal location for the balloon control ring is not easily determined. In order to address this difficulty, this study investigates the variation in the radius of a free balloon and examines the effect of balloon control rings of various diameters at different locations on yarn tension and balloon flutter stability. The results indicate that the maximum radius of a free balloon and its corresponding position depend not only on the yarn-length to balloon-height ratio, but also on yarn type and count. A control ring of suitable radius and position can significantly reduce yarn tension and decrease flutter instability of free single-loop balloons. While the balloon control rings are usually fixed to, and move in sinc with, the ring frame, results reported in this study suggest that theoretically, a balloon control ring that always remains approximately half way between the yarn-guide and the ring rail during spinning can lead to significant reduction in yarn tension.

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Bothrops marajoensis is found in the savannah of Marajo Island in the State of Par S and regions of Amapa State, Brazil. The aim of the work was to study the renal and cardiovascular effects of the B. marajoensis venom and phospholipase A(2) (PLA(2)). The venom was fractionated by Protein Pack 5PW. N-terminal amino acid sequencing of sPLA(2) showed amino acid identity with other lysine K49sPLA(2)s of snake venom. B. marajoensis venom (30 mu g/mL) decreased the perfusion pressure, renal vascular resistance, urinary flow, glomerular filtration rate and sodium tubular transport. PLA(2) did not change the renal parameters. The perfusion pressure of the mesenteric bed did not change after infusion of venom. In isolated heart, the venom decreased the force of contraction and increased PP but did not change coronary flow. In the arterial pressure, the venom and PLA(2) decreased mean arterial pressure and cardiac frequency. The presence of atrial flutter and late hyperpolarisation reversed, indicating QRS complex arrhythmia and dysfunction in atrial conduction. In conclusion, B. marajoensis venom and PLA(2) induce hypotension and bradycardia while simultaneously blocking electrical conduction in the heart. Moreover, the decrease in glomerular filtration rate, urinary flow and electrolyte transport demonstrates physiological changes to the renal system. (C) 2009 Elsevier Ltd. All rights reserved.

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Most of the established procedures for analysis of aeroelastic flutter in the development of aircraft are based on frequency domain methods. Proposing new methodologies in this field is always a challenge, because the new methods need to be validated by many experimental procedures. With the interest for new flight control systems and nonlinear behavior of aeroelastic structures, other strategies may be necessary to complete the analysis of such systems. If the aeroelastic model can be written in time domain, using state-space formulation, for instance, then many of the tools used in stability analysis of dynamic systems may be used to help providing an insight into the aeroelastic phenomenon. In this respect, this paper presents a discussion on the use of Gramian matrices to determine conditions of aeroelastic flutter. The main goal of this work is to introduce how observability gramian matrix can be used to identify the system instability. To explain the approach, the theory is outlined and simulations are carried out on two benchmark problems. Results are compared with classical methods to validate the approach and a reduction of computational time is obtained for the second example. © 2013 Douglas Domingues Bueno et al.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The present work describes an alternative methodology for identification of aeroelastic stability in a range of varying parameters. Analysis is performed in time domain based on Lyapunov stability and solved by convex optimization algorithms. The theory is outlined and simulations are carried out on a benchmark system to illustrate the method. The classical methodology with the analysis of the system's eigenvalues is presented for comparing the results and validating the approach. The aeroelastic model is represented in state space format and the unsteady aerodynamic forces are written in time domain using rational function approximation. The problem is formulated as a polytopic differential inclusion system and the conceptual idea can be used in two different applications. In the first application the method verifies the aeroelastic stability in a range of air density (or its equivalent altitude range). In the second one, the stability is verified for a rage of velocities. These analyses are in contrast to the classical discrete analysis performed at fixed air density/velocity values. It is shown that this method is efficient to identify stability regions in the flight envelope and it offers promise for robust flutter identification.

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This paper presents a new methodology to analyze aeroelastic stability in a continuous range of flight envelope with varying parameter of velocity and altitude. The focus of the paper is to demonstrate that linear matrix inequalities can be used to evaluate the aeroelastic stability in a region of flight envelope instead of a single point, like classical methods. The proposed methodology can also be used to study if a system remains stable during an arbitrary motion from one point to another in the flight envelope, i.e., when the problem becomes time-variant. The main idea is to represent the system as a polytopic differential inclusion system using rational function approximation to write the model in time domain. The theory is outlined and simulations are carried out on the benchmark AGARD 445.6 wing to demonstrate the method. The classical pk-method is used for comparing results and validating the approach. It is shown that this method is efficient to identify stability regions in the flight envelope. (C) 2014 Elsevier Ltd. All rights reserved.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This paper shows the application of a hysteretic model for the Magnetorheological Damper (MRD) placed in the plunge degree-of-freedom of aeroelastic model of a wing. This hysteretic MRD model was developed by the researchers of the French Aerospace Lab. (ONERA) and describe, with a very good precision, the hysteretic behavior of the MRD. The aeroelastic model used in this paper do not have structural nonlinearities, the only nonlinearities showed in the model, are in the unsteady flow equations and are the same proposed by Theodorsen and Wagner in their unsteady aerodynamics theory; and the nonlinearity introduced by the hysteretic model used. The main objective of this paper is show the mathematical modeling of the problem and the equations that describes the aeroelastic response of our problem; and the gain obtained with the introduction of this hysteretic model in the equations with respect to other models that do not show the this behavior, through of pictures that represents the time response and Phase diagrams. These pictures are obtained using flow velocities before and after the flutter velocity. Finally, an open-loop control was made to show the effect of the MRD in the aeroelastic behavior.

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A nonlinear analysis is performed for the purpose of identification of the pitch freeplay nonlinearity and its effect on the type of bifurcation of a two degree-of-freedom aeroelastic system. The databases for the identification are generated from experimental investigations of a pitch-plunge rigid airfoil supported by a nonlinear torsional spring. Experimental data and linear analysis are performed to validate the parameters of the linearized equations. Based on the periodic responses of the experimental data which included the flutter frequency and its third harmonics, the freeplay nonlinearity is approximated by a polynomial expansion up to the third order. This representation allows us to use the normal form of the Hopf bifurcation to characterize the type of instability. Based on numerical integrations, the coefficients of the polynomial expansion representing the freeplay nonlinearity are identified. Published by Elsevier Ltd.