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Modélisation des efforts aérodynamiques instationnaires pour la prévision du phénomène de tremblement sur des avions civils
Get PDFLe tremblement est un phénomène qui touche diverses parties de l'avion, pouvant créer des problèmes de fatigue structurelle ou de confort et limiter l'enveloppe de vol. Il est par conséquent important de comprendre ce phénomène afin de mieux le prévoir. Quatre types de tremblement sont étudiés dans cette thèse, le tremblement de l'empennage horizontal, le tremblement intrados voilure, le tremblement de l'APF et le tremblement de l'extrados voilure. La première partie du mémoire détaille la physique de ces phénomènes à partir d'informations recueillies dans la littérature et de l'analyse de différentes campagnes d'essais en soufflerie. Cette partie met ainsi en évidence les caractéristiques instationnaires propres à chaque type de tremblement. La deuxième partie présente l'état de l'art sur la prévision du tremblement, permettant de montrer non seulement les défauts associés aux méthodes antérieures de modélisation mais également les avantages de l'utilisation de certains outils comme l'approche numérique pour mieux comprendre ces phénomènes. Finalement, la troisième partie présente le nouveau modèle semi-empirique basé sur les fonctions de cohérence et développé pour mieux représenter les phénomènes de tremblement étudiés. Une validation de ce modèle a été effectuée sur les différentes campagnes d'essais en soufflerie, donnant des résultats probants pour la plupart des phénomènes étudiés.The buffeting is a phenomenon that can affect various parts of the aircraft creating problems of structural fatigue or comfort as well as limiting the flight envelope. It is hence important to understand this phenomenon in order to be able to better predict it. Four types of buffeting are studied in this thesis, the horizontal tail plane buffeting, the wing lower surface buffeting, the APF buffeting and the wing upper surface buffeting. The first part of the thesis describes the physics of these phenomena based on the information collected in the literature and analysis of different wind tunnel test campaign data. This section highlights the unsteady characteristics of each buffeting phenomenon. The second part presents the state of the art of the buffeting prediction, showing not only the difficulties associated with previous modelling methods but also the benefits of the use of certain tools such as CFD to better understand these phenomena. Finally, the third part presents the new semi-empirical model based on coherence functions and developed to better predict the different types of buffeting. A validation of this model was performed on various wind tunnel tests campaigns giving very good results for most of the analysed phenomena.TOULOUSE-ISAE (315552318) / SudocSudocFranceF
Raréfaction dans les suites b-multiplicatives
Get PDFOn étudie une sous-classe des suites b-multiplicatives rarefiées avec un pas de raréfaction p premier, et on trouve une structure asymptotique avec un exposant alphain]0,1[ et une fonction de raréfaction continue périodique. Cette structure vaut pour les suites qui contiennent des nombres complexes du disque unité (section 1.1), et aussi pour des systèmes de numération avec b chiffres successifs positifs et négatifs (section 1.2). Ce formalisme est analogue à celui décrit (pour le cas particuler de la suite de Thue-Morse) par Gelfond; Dekking; Goldstein, Kelly, Speer; Grabner; Drmota, Skalba et autres. Dans la deuxième partie, largement indépendante, on étudie la raréfaction dans les suites composées de -1,0 et +1. On se restreint davantage au cas où b engendre le groupe multiplicatif modulo p. Cette hypothèse est conjecturée (Artin) d'être vraie pour une infinité de nombres premiers. Les constantes qui apparaissent s'expriment alors comme polynômes symétriques des P(zeta^j) où P est un polynôme à coefficients entiers, zeta est une racine primitive p-ième de l'unité, parcourt les entiers de 1 à p-1 (ce lien est explicité dans la section 1.3). On définit une méthode pour étudier les valeurs de ces polynômes symétriques, basée sur la combinatoire, notamment sur le problème de comptage des solutions des congruences et des systèmes linéaires modulo p avec deux conditions supplémentaires: les résidus modulo p utilisés doivent être non nuls et différents deux à deux. L'importance est donnée à la différence entre les nombres de soluions de deux congruences qui ne diffèrent que du terme sans variable. Le cas des congruences de la forme équivaut à un résultat connu. Le mémoire (section 2.2) lui donne une nouvelle preuve qui en fait une application originale de la formule d'inversion de Möbius dans le p.o.set des partitions d'un ensemble fini. Si au moins deux coefficients distincts sont présents, on peut classer les réponses associées à toutes les congruences possibles qui ont un ensemble fixe de coefficients (de taille d), dans un tableau qu'on va appeler un "simplexe de Pascal fini". Ce tableau est une fonction delta:N^d->Z restreinte aux points de somme des coordonnées inférieure à p (un simplexe), avec deux propriétés: l'équation récursive de Pascal y est vérifiée partout sauf les points où la somme des coefficients est multiple de p (qui seront appelés les "sources" et forment un sous-réseau de l'ensemble des points entiers), et les valeurs en-dehors du simplexe induites par l'équation sont nulles (c'est démontré, en réutilisant la méthode précédente, dans la section 2.3 et en partie 2.4). On décrit un algorithme (section 2.4) qui consiste en applications successives de l'équation dans un ordre précis, qui permet de trouver l'unique fonction delta qui vérifie les deux conditions. On applique ces résultats aux suites b-multiplicatives (dans la section 2.5). On montre aussi que le nombre de sources ne dépend que de la dimension du simplexe d et de la longueur de son côté p. On formule la conjecture (partie 2.6) qu'il serait le plus petit possible parmi les tableaux de forme d'un simplexe de la dimention fixe et taille fixe qui vérifient les mêmes conditions. On montre un premier résultat sur les systèmes de deux congruences linéaires (section 2.5.4), et on montre (section 1.4) un lien avec une méthode de Drmota et Skalba pour prouver l'absence de phénomène de Newman (dans un sens précis), décrit initialement pour la suite de Thue-Morse et tout p tel que b engendre le groupe multiplicatif modulo p, et généralisé (section 1.4) à la suite (-1)^{nombre de chiffres 2 dans l'écriture en base 3 de n} appelée "++-". Cette problématique est riche en problèmes d'algorithmique et de programmation. Différentes sections du mémoire sont illustrées dans l'Annexe. La plupart de ces figures sont inédites.The primary object of study is a subclass of b-multiplicative sequences, p-rarefied which means that the subsequence of terms of index multiple of a prime number p is taken. The sums of their initial terms have an asymptotic structure described by an exponent alphain]0,1[ and a contnous periodic "rarefaction function". This structure is valid for sequences with complex values in the unit disc, in both cases of the usual numerating system (section 1.1) and one with b successive digits among which there are positive and negative (section 1.2). This formalism is analogous to the formalism for the Thue-Morse sequence in texts by Gelfond; Dekking; Goldstein, Kelly, Speer; Grabner; Drmota, Skalba and others. The second, largely independent, part concerns rarefaction in sequences with terms in -1,0 or 1. Most results concern the case where b is a generator of the multiplicative group modulo p. This condition has been conjectured to be valid for infinity of primes, by Artin. The constants which are important, can be written as symmetric polynomials of P(zeta^j) where zeta is a primitive p-th root of unity, P is a polynomial with integer coefficients and j runs through the numbers from 1 to p-1 (section 1.3). The text describes a combinatorics-based method to study the values of these symmetric polynomials, where the combinatorial problem is as follows. Count the solutions of a linear congruence or a system modulo p, which satisfy a condition: the values of variables must be different from each other and from zero. Importance is attached to the difference between the numbers of solutions of two congruences that differ only in the free term. For the congruences of the form this problem reduces to a well-known result. The text (section 2.2) gives an original proof of it, using the Möbius inversion formula in the p.o.set of partitions of a finite set. If at least two distinct coefficients are present, we can fix a set of coefficients (of size d) and put the answers corresponding to all possible linear congruences into an array that will be called "finite Pascal's triangle". It is a function delta:N^d->Z restricted to inputs with the sum of coordinates smaler than p (a simplex), and it has two properties. A recursive equation similar to the equation of Pascal holds everywhere except the points where the sum of coefficients is a multiple of p (a sublattice of Z^d the points of which are called "sources"); the values induced by this equation beyond the simplex are zeroes (section 2.3 and part of 2.4). An algorithm that finds the unique function delta satisfying these condiditions is described (section 2.4). It consists in successive applications of the equation in a precise order. These results are then applied to the b-multiplicative sequences (section 2.5). We also prove that the number of sources depends only on the dimention d and the size p of the simplex. We conjecture (section 2.6) that this number is the smallest possible for all numerical arrays of the same dimention and size that satisfy the same conditions. A first result about the systems of two linear congruences is proved (section 2.5.4). It is shown how these systems are related to a method by Drmota and Skalba of proving the absence of Newman's phenomenon (in a precise sence) initially described for the Thue-Morse sequence and for a prime p such that 2 is a generator of the multiplicative group modulo p, then extended to the sequence (-1)^{number of digits 2 in the ternary extension of n} called "++-". These questions generate many algorithmic and programming problems. Several sections link to illustration situated in the Annexe. Most of these figures are published for the first time.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF
La perception visuelle (un facteur déterminant dans la reconstruction photomimétique d'un sourire)
No full textTOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF
Les médecins généralistes utilisent ils la loi Léonetti ? (par Céline Paret)
No full textDepuis 2005, la loi Léonetti organise la prise en charge des patients notamment lors de la fin de vie. De récents débats ont amené à se questionner sur sa connaissance par les praticiens. L objet de ce travail est d interroger les compétences des médecins en situation. Il s agit d une enquête par questionnaire entre mai 2013 et septembre 2013 auprès de médecins généralistes installés en ville dans le département des Hauts de Seine. Un questionnaire structuré en deux parties a été créé sur le site de sondage Survey Monkey® et envoyé aux médecins via les Présidents des associations de Formation Médicale Continue. La première partie posait des questions fermées d ordre général, la deuxième était composée de 5 cas cliniques avec des questions ouvertes. Pour répondre à ces dernières, les médecins devaient s appuyer sur les principes énoncés par la loi Léonetti. Les réponses ont été analysées par double lecture. 24 médecins ont répondu au questionnaire. Le principe du double effet a été intégré par une majorité de médecins. Pour les directives anticipées, les résultats étaient discordants dans les deux cas cliniques l abordant. Le respect de la volonté du patient a été intégré par une majorité de médecin. Le principe de discussion collégiale a été intégré par une minorité de médecin. Le principe de refus de l obstination n a pas été cité. Le faible nombre de réponses ne permet pas de conclure. Mais les tendances dégagées rejoignent les études précédentes : la loi Léonetti ne semble pas intégrée dans la pratique des médecins généralistesPARIS12-CRETEIL BU Médecine (940282101) / SudocSudocFranceF
Employee status and collectivism : a study of managerial and professional trade unionism
No full textThis research examines the managerial and professional status of members of three case-study unions: Nautilus International, Prospect and the Transport and Salaried Staffs' Association (TSSA). It considers the extent to which members' behaviour in these unions constitutes a shift away from the individual and towards the collective. Where these members have traditionally sought to preserve their career and livelihood by reinforcing individualism and self-interest, a definitive set of circumstances driven by labour market and workplace change has produced an unlikely materialisation in the form of collectivism. This research demonstrates how facets that have previously characterised, in existing literature, the managerial and professional worker, are undergoing something of a reconfiguration. For example, attitudes towards political neutrality, preference for a non-militant, conciliatory bargaining machinery and aversion to industrial action are changing among members of the case-study unions. This sea-change is subtle, inconspicuous, at times tentative, and by no means indicative of a large-scale transformation, and yet it is notable in terms of identifying a behavioural and attitudinal move away from what have been considered to be the 'benefits' of individualism and towards support for a collective approach. The research focuses on the roles of key actors (predominantly managerial and professional-grade members of the three unions) and analyses the scope of change to which they have been exposed, and how this has informed an inclination towards collectivism. This process discovered three key themes around which key actors were found to cohere: partnership, industrial action and political profile and affiliation. How these aspects were addressed by the three unions provide a valuable insight into the way in which these unions are sustaining resilience against a more general backdrop of trade union membership decline. The study concludes that an aggregation of economic, political and work factors have combined to produce an environment that has become conducive to collectivism among managerial and professional workers in the three case-study unions. This process, termed sub-collectivism here, is sophisticated, and is found to occur in many cases almost by default; cultivated inadvertently as this group of workers attempts to harness stability in a workplace whose complexion is increasingly comparable to that of their manual, or blue-collar, counterparts and whose precariousness is undoubtedly gathering momentum.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Mild everyday altered states of consciousness
No full textThis thesis presents an ethnographic study of altered states of consciousness (ASCs). Such states have been of interest to some writers in social anthropology (Turner 1992, Bourguignon 1989) and in some areas of psychology, especially transpersonal psychology (Beischel et al 2011:114, Vaughan 1993:160). But these literatures reveal a focus on rather extreme experiences not found in everyday life. There has been very little interest in milder altered states which are very common in our experience. These became the focus of the project. A literature review begins with an appraisal of writing in mainstream psychology on consciousness. A lack of study of ASCs is identified. The work of William James is reviewed as an important theorist for this thesis in his study of consciousness, particularly his 'stream of consciousness' (James 1950:239). James is seen to form a bridge between mainstream psychology and the development of trans personal psychology, a central theoretical perspective for this thesis. The development ofthe transpersonal psychology movement is explored. The transpersonal concerns 'those experiences which allegedly enable the individual to see beyond the conditioned ego and to identify some deeper and more enduring sense of self (Fontana & Slack 2005:7). The work of Maslow, Stanislav Grof and James is reviewed, particularly James's work on mystical states (James 1982, 1911). Key theoretical issues are identified: the problem of belief, universalism/relativism debates, validity of spiritual experience, and the 'participatory' in the work of Jorge Ferrer. Transpersonal anthropology is a sister movement and forms the second key theoretical perspective. Anthropological study of religion and spiritual beliefs and practices is traced through its early history in the work of Lucien Levy-Bruhl and Emile Durkheim. The Literary Turn in anthropology and also the participatory as a method are seen to open up the study of trans personal experience on its own terms. The work of Victor and Edith Turner forms a key reference point in this review. Key issues explored in transpersonal psychology are revisited here. A short consideration of literature on ASCs as healing is also presented, as well as literatures specific to each group studied. The methodology used draws on theoretical and practical debates around dialogic anthropology, and also participant observation. The history and development of ethnography is explored, particularly the 'Writing Culture' debates. Ethnographic fieldwork was carried out over a period of three years. Groups of individuals were chosen whose activities were ASC-inducing. These were members of a Hindu temple and a Lubavitch Jewish synagogue, members of a sport training group, users of a local forest , a musical instrument-maker group who were also musicians, and various excessive viewers of television. Fieldwork revealed patterns and types of ASCs, many of which are not found in the literature: absorbed, daydream and transcendent types; mindful/mindless ASCs; 'top-up' ASCs; a sport triple ASC; a total 'Lifeworld' ASC, a dialogue between positive and negative ASCs, and ASCs reaching beyond the self. The therapeutic value of these are highlighted in the lives of participants. Wider patterns are also discussed, such as sacred experience in secular contexts, collective ASCs and 'communitas' (Turner 2012), and challenges to boundaries of so-called 'reality out there' and fantasy.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Investigations into the effects of cholesterol inhibitors on cancer cells in vitro
No full textCholesterol-rich membrane microdomains have a significant role in cancer progression, particularly in metastasis, and there is evidence that cholesterol inhibitors, most notably statins, can change the behaviour of cancer cells in vitro and in vivo. Cholesterol-rich rafts act as loci for signal receptor-ligand binding, providing a stable scaffold for protein interaction. The purpose of this research was to test the hypothesis that the abundance of these inclusions can be controlled with cholesterol inhibitors and to investigate the effects of these treatments on cancer cells using simple in vitro assays. Flask shaped cholesterol-rich scaffolds in the membrane called caveolae, characterised by the presence of the protein Caveolin-l, are generally associated with proliferation suppression during oncogenesis but with tumour promotion during metastasis. This dual role may be coordinated by the cholesterol content of the raft environment and so be vulnerable to cholesterol inhibitors such as the statins. A variety of techniques were used to assess the proteome, mRNA expression, cholesterol and Cav-l levels in cells treated with a variety of cholesterol synthesis inhibitors in an attempt to understand the processes that affect metastatic behaviours in vitro. A number of novel derivatives of one particular inhibitor of cholesterol 1124 reductase (Proadifen) were included in these in vitro assays. The structure of the molecule was iteratively changed to determine the important features of the molecule that give rise to 1\-24 enzyme inhibition. It was found that inhibition of cholesterol synthesis asymmetrically reduces the prevalence of rafts and caveolae and is associated with multiple effects on cancer cell behaviour and, perhaps most significantly, with changes to gene expression. Targeted blockade of the mevalonate pathway using 1\-24 and 1\-7 reductase inhibitors could prevent the successful transduction of extrinsic signals that coordinate some cancer cell behaviour. The toxicity profiles of the inhibitors used in this project are poor, but further analogues may be developed in the future that could have clinical relevance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
The possibility of risk : an exploration of failure as success through the creation of contemporary ceramic artwork based upon the Korean Moon Jar
No full textThis research describes, analyses and evaluates the technical processes behind a series of original ceramics artworks, which take varying degrees of technical risks in the making process. The aesthetic evaluation of these artworks indudes the ways in which the ceramic artworks might be perceived as successful or unsuccessful. The traditional Korean moon jar was adopted as the primary form to investigate taking risks in the making in addition to the employment of many traditional procedures and processes. Historically, these unusual yet now highly acclaimed ceramic treasures were underestimated, and were regarded in the history of Korean ceramics as failed artworks. This common perception significantly influenced this project to reinterpret and recontextualise the value of traditional Korean moon jars. The viewer is confronted with an artwork, which challenges the paradigm of traditional ceramic practice. This research explores the ways in which Korean moon jars can reveal elements of risk taking in the making process and describes the key characteristics of risk taking. Methodologies deployed include the creation of original ceramic artworks through an investigation and interpretation of the making process; a review and interpretation of historical and contemporary material including archives, databases, museums and galleries; and case studies of artists and critics through interviews, electronic correspondence and questionnaires. Conclusions drawn from the research include an aesthetic and critical interpretation of taking risks in the making of Korean moon jars. They contribute to the paucity of research in this area, and assert the need for a critical re-assessment of Korean moon jars in contemporary ceramics. The written thesis makes a vital contribution to the limited published material regarding Korean moon jars, in particular the making process combined with the concept and practical features of risk-taking in sculptural moon jar forms. In addition, this research provides the first complete theorisation of tacit knowledge and workmanship of risk, with regards to the Korean moon jar and demonstrates the employment of failure or discarded pieces that contribute to aesthetic theorisation, such as the sublime within Korean scholarly ceramics. Taking risks during the making process became a key conceptual feature of the investigation and inspired three new understandings of deploying and evaluating risk taking while working in the medium of ceramics, with emphasis on the moon jar form.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
An investigation into the factors that attract young students to the Open University and support their studies to module completion
No full textThe research investigates the reasons why students aged 18-24 come to the Open University and the factors that influence their decision. It also examines their learning experience and the key factors that lead to successful study. The research population comprised new Open University students with no previous higher education qualification, studying one of four introductory level modules in the Faculties of Arts, Social Sciences, Health and Social Care or Science. Data were compared by module and from students aged 18-20 (Group 1) and 21-24 (Group 2). An online survey was administered to 827 students and yielded 231 responses. In addition, 40 students volunteered to participate in semi-structured email interviews. The discussion of the data was focused on the three theoretical concepts of transitions, networks of intimacy and cultural capital. The findings indicate that students' decisions about higher education study were mainly influenced by family members and friends. They were studying principally to improve their job or career prospects although many were seeking to redress negative educational experiences in the past and to prove to themselves and others that they could study successfully at higher education level. They were attracted to the Open University by its flexibility, cost-effectiveness and open access policy. Respondents' study experience was largely very positive but students in Group 1 in particular missed face -to-face tutor contact and social integration with other students. The majority of respondents in both groups expressed confidence about their progress on the module although women in particular had underlying doubts about their academic ability. Successful students had developed a number of coping strategies for managing the conflicting demands of work, study and family.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
Strategic marketing planning in the context of heritage tourism management : a study of two heritage regions
No full textThe effective strategic management of heritage tourism is vital to the economic, environmental and social health of a region. This is even more pronounced in heritage based regions where the resource is ultimately finite and where development cannot be separated from its local residents, communities and businesses. Given this scenario, the effective marketing of heritage tourism must take both a strategic approach and be underpinned by effective stakeholder engagement, which includes processes of coordination and integration in order to achieve a holistic approach to marketing management. The research sought to establish the nature and scope of stakeholders involved in strategic marketing planning within heritage regions, to investigate the coordination and management of strategic marketing functions, and to examine the process of strategic implementation. The empirical study took a qualitative approach guided by the case study methodology, which used a range of data collection techniques including content analysis and in-depth interviews. A range of data sources reflecting the structure of the tourism industry were used, including key strategic documents, public sector key informants and tourist product service providers operating in both the private and community sectors, representing the regions. Key contributions made by the research relate to the identification of four key issues including Strategic Direction, Marketing Communications, Consultation and Aggravated Fragmentation. Overall, it was found that there is no central strategic direction for tourism management, with the result that tourism delivery is unclearly and ambiguously assigned between myriad bodies and agencies. At strategic level, marketing communications between such bodies is endemically poor, resulting in a disintegrated approach to tourism marketing management. The implications of these weaknesses are evident across several strategic marketing functions, including Strategic Orientation, Resource Allocation, Product Service Development and Destination Promotion, and are significant across the levels of management and administration for tourism, from government level planning to individual tourism providers.EThOS - Electronic Theses Online ServiceGBUnited Kingdo