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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1431

Ecoulements de suspensions concentrées de globules rouges en micro-canaux : étude expérimentale / Flows of concentrated suspensions of red blood cells in microchannels : an experimental study

Roman, Sophie 13 December 2012 (has links)
Le sang est une suspension concentrée (45 % en volume) de cellules déformables, les globules rouges, dans un liquide newtonien, le plasma. Dans la microcirculation, i.e. le sous-ensemble du système de circulation sanguine où s'effectuent les échanges de matière entre le sang et les tissus, les tailles de vaisseaux sont comparables à la taille d'un globule rouge (environ 10 µm). En conséquence, les effets dynamiques liés à la présence de ces cellules induisent des comportements rhéologiques complexes, qui jouent un rôle important dans le transport de l'oxygène vers les tissus. En particulier, aux bifurcations microvasculaires divergentes, les débits de globules rouges et de plasma peuvent se répartir de façon non proportionnelle entre les deux branches filles. La fraction volumique de globules rouges (hématocrite) dans l'une des branches filles est alors plus élevée que celle de la branche d'entrée, et la fraction volumique dans l'autre branche y est plus faible. Cet effet, connu sous le nom d'effet de séparation de phase, induit une très grande hétérogénéité de l'hématocrite d'un vaisseau à l'autre dans la microcirculation. Il induit également un couplage entre l'architecture du réseau microvasculaire et la dynamique de l'écoulement sanguin dans ce réseau. L'objectif de ce travail de thèse est d'étudier finement l'effet de séparation de phase in vitro, dans un régime représentatif des conditions physiologiques, au moyen de dispositifs microfluidiques modélisant les bifurcations microvasculaires et de suspensions de globules rouges. Dans ce but, un dispositif expérimental microfluidique a d'abord été élaboré. Puis, les aspects métrologiques spécifiques aux suspensions concentrées ont été abordés afin de quantifier les paramètres de l'écoulement. En particulier, la technique de dual-slit a été comprise et optimisée, assurant une mesure précise de profils de vitesse de globules rouges en microcanaux. Des métrologies spécifiques à nos conditions expérimentales ont également été mises en place pour déterminer l'hématocrite. Ces techniques ont été validées par vérification du principe de conservation de la masse entre les trois branches d'une bifurcation, et elles nous ont permis de caractériser les écoulements de globules rouges dans des micro-canaux de différentes tailles (10 à 100 µm), et ce pour de larges gammes de débits et de concentrations. Enfin, l'écoulement de suspensions de globules rouges a été étudié au niveau de micro-bifurcations, dans l'objectif de caractériser l'effet de séparation de phase pour des tailles de canaux et des gammes d'hématocrites qui n'ont pas été étudiés auparavant en conditions d'écoulement maîtrisées. / Blood is a concentrated suspension (45% by volume) of deformable red blood cells, flowing in a Newtonian fluid called plasma. The microcirculation is the part of the blood circulation system where the exchanges of material (e.g. nutrients, oxygen) between the blood and tissues take place. The microvessels are characterized by diameters less than 100 microns, which is similar in size to the size of a red blood cell ( 10 microns). As a result, the presence of these cells considerably influences the dynamics of microvascular flows and induces complex rheological behaviors. In particular, at diverging microvascular bifurcations, red blood cells and plasma may be nonproportionally distributed between two daughter vessels : one gets a higher red blood cell volume fraction (hematocrit) than the feeding vessel, while the other gets a lower one. This effect, known as the phase separation effect, causes a tremendous heterogeneity of the hematocrit among vessels in microvascular networks and induces a coupling between the microvascular architecture and the blood flow dynamics. The aim of this thesis is to investigate the phase separation effect in vitro, in physiological conditions, using red blood cell suspensions and microfluidic devices modeling microvascular bifurcations. For this purpose, a microfluidic experimental device was first developed. Then the metrological aspects specific to concentrated suspensions were addressed in order to quantify all the flow parameters. In particular, the dual-slit technique has been understood and optimized, ensuring accurate measurement of velocity profiles of red blood cells in microchannels. Measurement methods for our experimental conditions were also implemented to determine the hematocrit. All these techniques have been validated by verification of the principle of mass conservation between the three branches of a bifurcation. They allowed us to characterize the flow of red blood cells in microchannels of different sizes (10 to 100 microns) and for wide ranges of flow rates and concentrations. Finally, the flow of red blood cell suspensions was investigated at micro-bifurcations, with the aim of characterizing the phase separation effect for channel sizes and hematocrit ranges never studied in controlled flow conditions.
1432

Nejvyšší soud USA - jeho vznik a prvá klíčová rozhodnutí / The US Supreme Court, its, formation and first key decisions

Miřejovský, Jan January 2011 (has links)
The US Supreme Court, its formation and first key decisions The thesis offers an insight of an era in which the Supreme Court of United States was founded and established itself as one of the major government institutions as well as a strong powerhouse of American politics. Essential for understanding of the future importance and role of the Court is to perceive not only its own early history but also an understanding of broader context concerning a development of the early American society as a whole. The thesis based on this implied layout consists of three main chapters. The first attempts to grasp a vast set of conditions which served, each to a different extent, as an inspirational background influence for the Founders in the creation of an American statehood. The natural rights philosophy, a product of the Age of Enlightenment, introduced by the work of John Locke set a foundation for American political thinking. The natural rights approach gloriously manifested itself in the Declaration of Independence (1776) and from then on runs as a red thin line throughout the entire legal history of United States. The Founders in the creation of a new American order amalgamated their knowledge of past human endeavors in various state systems and social structures into a constitutional based system of...
1433

Online source separation in reverberant environments exploiting known speaker locations

Harris, Jack D. January 2015 (has links)
This thesis concerns blind source separation techniques using second order statistics and higher order statistics for reverberant environments. A focus of the thesis is algorithmic simplicity with a view to the algorithms being implemented in their online forms. The main challenge of blind source separation applications is to handle reverberant acoustic environments; a further complication is changes in the acoustic environment such as when human speakers physically move. A novel time-domain method which utilises a pair of finite impulse response filters is proposed. The method of principle angles is defined which exploits a singular value decomposition for their design. The pair of filters are implemented within a generalised sidelobe canceller structure, thus the method can be considered as a beamforming method which cancels one source. An adaptive filtering stage is then employed to recover the remaining source, by exploiting the output of the beamforming stage as a noise reference. A common approach to blind source separation is to use methods that use higher order statistics such as independent component analysis. When dealing with realistic convolutive audio and speech mixtures, processing in the frequency domain at each frequency bin is required. As a result this introduces the permutation problem, inherent in independent component analysis, across the frequency bins. Independent vector analysis directly addresses this issue by modeling the dependencies between frequency bins, namely making use of a source vector prior. An alternative source prior for real-time (online) natural gradient independent vector analysis is proposed. A Student's t probability density function is known to be more suited for speech sources, due to its heavier tails, and is incorporated into a real-time version of natural gradient independent vector analysis. The final algorithm is realised as a real-time embedded application on a floating point Texas Instruments digital signal processor platform. Moving sources, along with reverberant environments, cause significant problems in realistic source separation systems as mixing filters become time variant. A method which employs the pair of cancellation filters, is proposed to cancel one source coupled with an online natural gradient independent vector analysis technique to improve average separation performance in the context of step-wise moving sources. This addresses `dips' in performance when sources move. Results show the average convergence time of the performance parameters is improved. Online methods introduced in thesis are tested using impulse responses measured in reverberant environments, demonstrating their robustness and are shown to perform better than established methods in a variety of situations.
1434

19th century emigration from Cornwall as experienced by the wives 'left behind'

Trotter, Lesley Jane January 2015 (has links)
The 19th century is recognised as a period of mass emigration from Cornwall, with a significant proportion of the male population leaving to work overseas, mainly in the mining industry. Less appreciated is that many of these migrants were married men who left wives and children behind in Cornwall. This study seeks to shed some light on the experiences of these women, known as 'married widows'. It adopts a multi-faceted approach, which draws upon crowd-sourcing and digital resources, in combination with more traditional methodologies. Scattered and fragmentary qualitative evidence (drawn from correspondence, newspapers, remittance and poor law records, supplemented by personal testimony recorded in family histories) is examined within a quantitative framework produced by an innovative database created from census records and a longitudinal study of outcomes. This thesis describes how tens of thousands of wives were 'left behind' in the mining communities of Cornwall, and the wide range of resources they drew upon in the absence of their husbands. It examines the interaction between the wives and the State in the form of the Poor Law and the Courts, identifying a pragmatic response to the needs of the emerging transnational nuclear family. Male migration from Cornwall is revealed to vary widely in type, intent and duration, leading to great diversity of experiences and outcomes for the wives 'left behind'. The establishment of temporary male labour emigration from the Cornish mining communities is shown to have occurred earlier than in many other emigration centres, creating greater potential for cultural acclimatisation to the challenges of spousal separation. The findings of this study challenge existing, generalised, perceptions of the wives as passive victims in the Cornish emigration story. Levels of destitution or desertion appear low compared to the scale of the phenomenon, and wives are shown as active participants and influential voices in family strategies. Nonetheless, this study highlights the vulnerability and greater risks faced by the wives 'left behind', and identifies financial and emotional insecurity as common elements of their experience. This thesis demonstrates a methodology and reveals insights that might be applied to the study of wives 'left behind' in other parts of the British Isles, and a comparator for existing studies of those elsewhere in the world.
1435

"Jag har bara sagt det så, för att andra inte ska skratta åt mig" : En kvalitativ ämnesdidaktisk studie om traditionella könsroller ur ett elevperspektiv

Djeordjic, Tijana January 2017 (has links)
The purpose of this study is to find out from a didactic perspective, how traditional gender roles emerge in the classroom and the conceptions of traditional gender roles. This is explored from a student’s perspective. The theoretical frame of this study is gender system, which consists of the principles of separation and hierarchy. The survey is conducted in two classes in third grade. This study answers following questions: How do traditional gender roles appear in the classroom from a student´s perspective? Which conception exist about traditional gender roles from a student's perspective? The study is based on observations and interviews, which is analysed of the gender system theory and the theoretical concept traditional gender roles. The results of this study show that the students' behavior in the classroom and their thinking are mostly based on the traditional gender roles, which is characterized mostly by the principles of separation and hierarchy.  However, some situations and statements show a change, in which the principles of separation and hierarchy are questioned. The individual situations reflect that the transfer of the gender contract is minimized from one generation to another.
1436

PARAMETERS GOVERNING SEPARATION CONTROL WITH SWEEPING JET ACTUATORS

Woszidlo, Rene, Woszidlo, Rene January 2011 (has links)
Parameters governing separation control with sweeping jet actuators over a deflected flap are investigated experimentally on a generic "Multiple Flap Airfoil" (MFA). The model enables an extensive variation of geometric and aerodynamic parameters to aid the scaling of this novel flow control method to full-size applications.Sweeping jets exit from discrete, millimeter-scale nozzles distributed along the span and oscillate from side-to-side. The sweeping frequency is almost linearly dependent on the supplied flowrate per actuator. The measured thrust exerted by a row of actuators agrees well with vectored momentum calculations. Frequency and thrust measurements suggest that the jet velocity is limited to subsonic speeds and that any additional increase in flowrate causes internal choking of the flow.Neither the flowrate nor the momentum input is found to be a sole parameter governing the lift for varying distance between adjacent actuators. However, the product of the mass flow coefficient and the square root of the momentum coefficient collapses the lift onto a single curve regardless of the actuator spacing. Contrary to other actuation methods, separation control with sweeping jets does not exhibit any hysteresis with either momentum input or flap deflection. A comparison between sweeping and non-sweeping jets illustrates the superior control authority provided by sweeping jets. Surface flow visualization on the flap suggests the formation of counter-rotating pairs of streamwise vortices caused by the interaction of neighboring jets.The actuation intensity required to attach the flow increases with increasing downstream distance from the main element's trailing edge and increasing flap deflection. No obvious dependence of the ideal actuation location on actuator spacing, flap deflection, angle of attack, or actuation intensity is found within the tested range. Comparisons between experimental and numerical results reveal that the inviscid flow solution appears to be a suitable predictor for the effectively and efficiently obtainable lift of a given airfoil configuration. The flap size affects the achievable lift, the accompanying drag, and the required flap deflection and actuation intensity. By controlling separation, the range of achievable lift coefficients is doubled without significant penalty in drag even when considering a safety margin for the maximum applicable incidence.
1437

Fonctions de coût pour l'estimation des filtres acoustiques dans les mélanges réverbérants / Cost functions for the estimation of acoustic filters in reverberant mixtures

Benichoux, Alexis 14 October 2013 (has links)
On se place dans le cadre du traitement des signaux audio multicanaux et multi-sources. À partir du mélange de plusieurs sources sonores enregistrées en milieu réverbérant, on cherche à estimer les réponses acoustiques (ou filtres de mélange) entre les sources et les microphones. Ce problème inverse ne peut être résolu qu'en prenant en compte des hypothèses sur la nature des filtres. Notre approche consiste d'une part à identifier mathématiquement les hypothèses nécessaires sur les filtres pour pouvoir les estimer et d'autre part à construire des fonctions de coût et des algorithmes permettant de les estimer effectivement. Premièrement, nous avons considéré le cas où les signaux sources sont connus. Nous avons développé une méthode d'estimation des filtres basée sur une régularisation convexe prenant en compte à la fois la nature parcimonieuse des filtres et leur enveloppe de forme exponentielle décroissante. Nous avons effectué des enregistrements en environnement réel qui ont confirmé l'efficacité de cet algorithme. Deuxièmement, nous avons considéré le cas où les signaux sources sont inconnus, mais statistiquement indépendants. Les filtres de mélange peuvent alors être estimés à une indétermination de permutation et de gain près à chaque fréquence par des techniques d'analyse en composantes indépendantes. Nous avons apporté une étude exhaustive des garanties théoriques par lesquelles l'indétermination de permutation peut être levée dans le cas où les filtres sont parcimonieux dans le domaine temporel. Troisièmement, nous avons commencé à analyser les hypothèses sous lesquelles notre algorithme d'estimation des filtres pourrait être étendu à l'estimation conjointe des signaux sources et des filtres et montré un premier résultat négatif inattendu : dans le cadre de la déconvolution parcimonieuse aveugle, pour une famille assez large de fonctions de coût régularisées, le minimum global est trivial. Des contraintes supplémentaires sur les signaux sources ou les filtres sont donc nécessaires. / This work is focused on the processing of multichannel and multisource audio signals. From an audio mixture of several audio sources recorded in a reverberant room, we wish to estimate the acoustic responses (a.k.a. mixing filters) between the sources and the microphones. To solve this inverse problem one need to take into account additional hypotheses on the nature of the acoustic responses. Our approach consists in first identifying mathematically the necessary hypotheses on the acoustic responses for their estimation and then building cost functions and algorithms to effectively estimate them. First, we considered the case where the source signals are known. We developed a method to estimate the acoustic responses based on a convex regularization which exploits both the temporal sparsity of the filters and the exponentially decaying envelope. Real-world experiments confirmed the effectiveness of this method on real data. Then, we considered the case where the sources signal are unknown, but statistically independent. The mixing filters can be estimated up to a permutation and scaling ambiguity. We brought up an exhaustive study of the theoretical conditions under which we can solve the indeterminacy, when the multichannel filters are sparse in the temporal domain. Finally, we started to analyse the hypotheses under which this algorithm could be extended to the joint estimation of the sources and the filters, and showed a first unexpected results : in the context of blind deconvolution with sparse priors, for a quite large family of regularised cost functions, the global minimum is trivial. Additional constraints on the source signals and the filters are needed.
1438

Mapeamento dinâmico da distribuição de pressão interfacial de argamassas em squeeze flow. / Dynamic interfacial pressure mapping of mortars undergoing squeeze flow.

Grandes, Franco Ancona 20 March 2019 (has links)
Argamassas no estado fresco são suspensões heterogêneas multifásicas com grande extensão granulométrica, tendo um comportamento relativamente complexo. Para a sua caracterização reológica já é empregado o ensaio de squeeze flow, método normalizado (ABNT NBR 15839/2010) que fornece informações importantes sobre o fluxo das argamassas em condições similares às de aplicação prática. No entanto, alguns fenômenos relevantes relacionados ao squeeze flow de suspensões não podem ser diretamente avaliados somente através da resposta padrão do ensaio (curva carga ou tensão vs. deslocamento), como o tipo de fluxo e a ocorrência de separação de fases, não havendo ainda um método consolidado para investigação destes efeitos. Neste contexto, uma técnica de mapeamento dinâmico da distribuição de pressão interfacial é apresentada como ferramenta para a complementação do método, visando permitir uma análise mais aprofundada durante o ensaio de squeeze flow em argamassas, nas configurações de área e de volume constante, que podem fornecer informações diferentes. Um método de quantificação gravimétrica da separação de fases foi empregado ainda para verificação do fenômeno. Essa metodologia inovadora requer desenvolvimento, e dessa forma são analisados, além da influência de variáveis do material, aspectos do ensaio e diferentes procedimentos de tratamento e calibração dos dados desenvolvidos para análise dos resultados. Modelos teóricos são utilizados para a comparação das distribuições de pressão experimentais com previsões para fluidos de comportamento conhecido, o que ajuda a indicar o tipo de fluxo predominante. O método desenvolvido mostrou grande potencial para a análise de fluxos complexos, sobretudo suspensões concentradas, e contribui com a ampliação do conhecimento sobre o comportamento reológico de argamassas e os fatores que o influenciam. / Mortars while in fresh state are multiphasic heterogeneous suspensions with wide granular extension, presenting a relatively complex behavior. For rheological evaluation the squeeze flow test is already employed, being a standard test (ABNT NBR 15839/2010) and providing relevant information about the flow behavior of mortars under conditions which are similar to those in practical situations. Nevertheless, important phenomena related to the squeeze flow of suspensions cannot be directly assessed by the usual results from the test (load or stress vs. displacement curves), like type of flow and the occurrence of phase separation. There is not yet a stablished method for the investigation of these effects. In this context, a dynamic pressure mapping technique is presented as a tool in addition to the method, aiming to achieve a more thorough analysis during the squeeze flow of mortars, both in constant area and constant volume configuration, which can provide different information. A phase separation quantification method was employed to validate the phenomenon. This original methodology require development, thus aspects regarding the test setup are analyzed, besides the influence of material, and different data treatment and calibration procedures developed for the analysis of test results. Theoretical models are employed for comparison between experimental pressure distribution and predictions for fluids with known behavior, which aids in the determination of flow regime predominance. The developed method has shown great potential for the analysis of complex fluids, especially concentrated suspensions, and contributes to the expansion of knowledge on the rheological behavior of mortars and the influencing factors.
1439

[en] DISSOLUTION OF A MARRIAGE: A STUDY ABOUT THE PROCESS OF DISSOLUTION OF CONJUGALITY / [pt] O DESENLACE CONJUGAL: UM ESTUDO SOBRE O PROCESSO DE DISSOLUÇÃO DA CONJUGALIDADE

VANESSA GEROSA DA SILVA RANGEL 07 December 2015 (has links)
[pt] Esta pesquisa tem como objetivo a investigação do processo de dissolução da conjugalidade, incluindo o luto decorrente desse processo. Para atingir tal objetivo, este estudo analisa os discursos de homens e mulheres sobre a separação conjugal, perpassando seus sentimentos, assim como, sua relação com os ex-cônjuges. Para realização deste trabalho, foram entrevistados 10 homens e 10 mulheres que ainda não tinham recasado, que ficaram casados ao menos 3 anos, que estavam separados há, no mínimo, 1 ano e, no máximo, 7 anos, e que tiveram filhos com os ex-parceiros. Enquanto as mulheres mencionam que os sentimentos seguintes à separação estavam relacionados ao sonho de amor desfeito, os homens relacionam esses sentimentos à perda do contato diário com os filhos. Com relação aos sentimentos atuais decorrentes da separação, embora mais frequentes nas falas femininas, sentimentos de autonomia, autovalorização e crescimento pessoal aparecem tanto no discurso dos homens quanto no depoimento das mulheres. Em contrapartida, sentimentos de tristeza são mencionados somente pelos homens, ainda que não tenham a mesma intensidade e frequência do período pós-separação. No que diz respeito à parentalidade, os dados ratificam a dificuldade dos pais em conversar sobre o processo de separação com os filhos. Por outro lado, os resultados indicam que a maioria dos participantes não teve sua capacidade parental diminuída logo após a separação. Nesta pesquisa, a maioria dos entrevistados manteve o mesmo padrão de relacionamento com o ex-cônjuge ao longo do tempo. A manutenção de um bom relacionamento com o ex-parceiro emerge mais nas falas femininas do que no discurso dos homens. Quanto aos casos de conflito e litígio, foi possível verificar como aspectos conjugais e parentais ficam emaranhados. / [en] This research has the intention of investigating the process of the dissolution of the conjugality, including the mourning derived from this process. To achieve such a goal, this study compares the speeches of men and women about the separation, showing their feelings, and their relationship with their ex-partners. In order to do this work, we interviewed 10 men and 10 women, that haven t remarried. They were married at least 3 years, were separated at least a year and at the most 7 years and had children with the ex-partner. While the women mention their feelings after separation are related to the loss of the dream love, the men relate those feelings to the loss of the contact with their kids. In relation with the feelings resulting of separation, even though more frequent in feminine speeches, feelings of self esteem and personal growth are often heard from men and women. On the other hand, sadness feelings are only mentioned by men, even though they don t have the same intensity and frequency of the period post separation. Related to the parenting, data shows the difficulty of parents to talk about the separation process with their kids. On the other hand, the result shows that the majority of the participants didn t have their parental capacity lowered right after separation. In this research, the majority of the interviewed kept the same relationship with the ex-partner with time. The maintenance of a good relationship with the ex-partner emerges more in feminine speeches than in men. As far as the conflicts and legal, was possible to verify how messy marriage and parenting can be.
1440

On-Board Data Aquisition System : Conceptual Design of an Airdrop Tracking System

Eriksson, Hanna January 2019 (has links)
This thesis is, on behalf of Saab AB, a pre-study of possible on-board solutions for position measuring during store separation tests aimed for the test and evaluation of JAS 39 Gripen. The purpose is to replace the present ground-based system in order to achieve more effective trials regarding time and economy. Three different concept development methodologies were investigated in order to find the most suitable one for this thesis. Those were merged into one adapted methodology containing the following phases; \textit{Planning}, \textit{Function Analysis}, \textit{Concept Generation} and \textit{Concept Evaluation}. The work progressed as the methodology states, and the highest amount of work was dedicated to the Planning phase. The requirements and desiderata for the system were produced with an agile process, resulting in the Construction Specification List that eventually became the basis for the Concept Generation phase. Knowledge about the technical theory needed to solve the problem was obtained in parallel with the Function Analysis and Concept Generation. The most adaptable techniques to measure position were found out to be with the use of the Global Positioning System (GPS) or Inertial Navigation System (INS). After an extensive work with the Concept Generation in parallel with a continuously updated Construction Specification List, three concepts were developed. One concept is based on GPS, the second one on INS and the third one is a combination of GPS and INS. All three concepts shares the same telemetry system and casing, which fulfills the requirement of simple installation and possibility to install in different stores. In the final phase, Concept Evaluation, a comparison between the concepts was performed. Advantages and disadvantages was listed and the fulfillment of requirements was investigated. All three concepts were handed over to Saab in order to let them decide which concept(s) to further develop.

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