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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.
51

Développement d'un traitement acoustique basses-fréquences pour application aérospatiale

Kerkeni, Dhia January 2015 (has links)
Résumé : Tout comme l’aéronautique, l’industrie aérospatiale s’est tournée progressivement vers l’emploi des coques à base des matériaux composites. Cette transition a permis d’alléger considérablement les structures aéronautiques et aérospatiales, et par conséquent, a réduit la consommation de carburants ainsi que l’impact écologique des aéronefs et des lanceurs. Toutefois, la loi de masse stipule que cela ne peut être sans conséquence sur la perte par transmission acoustique des panneaux, surtout sur les basses fréquences. Que ce soit pour la conformité aux exigences des normes aéronautiques en terme de niveau de pression acoustique à l’intérieur des cabines ou la protection des charges utiles dans les coiffes des lanceurs, les traitements acoustiques ciblant les basses fréquences s’avèrent un défi d’envergure. En effet, avec des contraintes très strictes de minimum de masse et de volume ajoutés, il est difficile de traiter les problèmes d’absorption acoustique basses-fréquences, avec les traitements phoniques classiques. Afin de tirer avantage des effets résonants pour améliorer l’absorption sur les basses fréquences, ce projet se propose d’étudier l’intégration d’écrans résistifs à très faibles épaisseurs dans les revêtements acoustiques, tout en minimisant le poids. Il a été proposé dans le cadre de la chaire industrielle de recherche en aéroacoustique dont les principaux bailleurs de fonds sont Bombardier aerospace, Pratt & whitney et Bell helicopter. Aussi, des travaux de recherche connexes se sont déroulés en partenariat avec ULA (United Launch Alliance). Ce travail de maîtrise comporte une partie bibliographique qui présente une étude exhaustive des traitements basses-fréquences existants, tout en y portant un regard critique. La partie théorique met particulièrement l’emphase sur les différents modèles de propagation d’onde et les phénomènes de dissipations dans les milieux poreux. Dans cette partie, on dénombre également les différents types d’écrans ainsi que les modèles de propagation correspondants. Des critères permettant une étude comparative objective du point de vue masse/performance ont été proposés. En plus des paramètres non acoustiques, les conditions de montage et d’agencement des couches ont été étudiées avec des simulations numériques appuyées par des mesures expérimentales. Dans l’avant dernier chapitre, un modèle SEA (Statical Energy Analysis) d’une coiffe de lanceur a été construit avec tous ses détails à partir d’un exemple concret. Les simulations se sont terminées avec une étude comparative de la réduction de niveau de pression acoustique dans la coiffe. Le dernier chapitre résume les principaux résultats et conclusions de cette étude. / Abstract : Over the last few decades, the aerospace industry has witnessed a significant emergence of the use of composite shells. The latter are continuously replacing the metallic ones. This transition allowed a significant weight reduction of flying structures. Consequently, it substantially lessened the fuel consumption and mitigated the environmental footprint of aircrafts and space launch vehicles. However, evoking the mass law, this transition clearly cannot be without consequences on the acoustic transmission loss of fuselage panels. Neither can it be on payload fairings, especially over the low frequencies. Whether to meet with the standards and regulations in terms of acoustic pressure levels inside the pressurized cabins or to protect the payloads inside the launchers fairings, acoustic treatments design targeting the low frequencies seems to be a challenging issue. Indeed, with very stringent constraints in terms of added weight and volume, it is difficult to deal with the low frequencies noise and vibration, using passive monolayers. In order to take advantage of the resonant effects in enhancing low frequencies absorption, this work intends to investigate the integration of heavy treatments of very low thicknesses in acoustic coatings while minimizing weight. It was conducted within the frame work of the industrial research chair in aeroacoustics, whose main funders are : Bombardier Aerospace, Pratt & Whitney and Bell Helicopter. Also, other related researches were jointly carried out in partnership with ULA (United Launch Alliance). This master thesis includes a bibliographical section which consists of an overview of the existing low-frequencies solutions while keeping a critical eye on most of them. The following theoretical part focuses on the different models describing wave s’ propagation and dissipation phenomena in porous media. In the same section, we also list the different types of screens and the corresponding propagation models. Criteria for an objective comparative study in terms of weight versus performance were suggested. In addition to non-acoustic parameters, the layout and the mounting conditions of the acoustic packages were also investigated by means of numerical simulations, seconded by experimental measurements. In the penultimate chapter, an SEA detailed model of a launcher fairing was built based on data taken from a concrete example. The simulations ended with a comparative study of the sound pressure level reduction in the inner fairing cavity. The final chapter summarizes the main findings, conclusions and perspectives of this study.
52

Implications of False-Positive Trisomy 18 or 21 Screening Test Results in Predicting Adverse Pregnancy Outcomes

Huang, Pinchia 13 October 2009 (has links)
No description available.
53

Detection of KRAS Synthetic Lethal Partners through Integration of Existing RNAi Screens

Christodoulou, Eleni 18 December 2014 (has links) (PDF)
KRAS is a gene that plays a very important role in the initiation and development of several types of cancer. In particular, 90% of human pancreatic cancers are due to KRAS mutations. KRAS is difficult to target directly and a promising therapeutic path is its indirect inactivation by targeting one of its Synthetic Lethal Partners (SLPs). A gene G is a Synthetic Lethal Partner of KRAS if the simultaneous perturbation of KRAS and G leads to cell death. In the past, efforts to identify KRAS SLPs with high-throughput RNAi screens have been performed. These studies have reported only few top-ranked SLPs. To our knowledge, these screens have never been considered in combination for further examination. This thesis employs integrative analysis of the published screens, utilizing additional, independent data aiming at the detection of more robust therapeutic targets. To this aim, RankSLP, a novel statistical analysis approach was implemented, which for the first time i) consistently integrates existing KRAS-specific RNAi screens, ii) consistently integrates and normalizes the results of various ranking methods, iii) evaluates its findings with the use of external data and iv) explores the effects of random data inclusion. This analysis was able to predict novel SLPs of KRAS and confirm some of the existing ones.
54

Mechanický čistící stroj / Mechanical cleaner-machine

Marek, Vlastimil January 2015 (has links)
This master’s thesis deals with design of mechanical screen cleaning machine for wastewater treatment plant, which will be placed in 800 mm wide and 1 850 mm deep intake canal. Thesis includes research of produced systems, construction design, drive unit design and other necessary strength and technical calculations. Thesis is supplemented by drawing of machine and its details.
55

Detection of KRAS Synthetic Lethal Partners through Integration of Existing RNAi Screens

Christodoulou, Eleni 15 December 2014 (has links)
KRAS is a gene that plays a very important role in the initiation and development of several types of cancer. In particular, 90% of human pancreatic cancers are due to KRAS mutations. KRAS is difficult to target directly and a promising therapeutic path is its indirect inactivation by targeting one of its Synthetic Lethal Partners (SLPs). A gene G is a Synthetic Lethal Partner of KRAS if the simultaneous perturbation of KRAS and G leads to cell death. In the past, efforts to identify KRAS SLPs with high-throughput RNAi screens have been performed. These studies have reported only few top-ranked SLPs. To our knowledge, these screens have never been considered in combination for further examination. This thesis employs integrative analysis of the published screens, utilizing additional, independent data aiming at the detection of more robust therapeutic targets. To this aim, RankSLP, a novel statistical analysis approach was implemented, which for the first time i) consistently integrates existing KRAS-specific RNAi screens, ii) consistently integrates and normalizes the results of various ranking methods, iii) evaluates its findings with the use of external data and iv) explores the effects of random data inclusion. This analysis was able to predict novel SLPs of KRAS and confirm some of the existing ones.
56

Κατασκευή οθόνης πολλαπλών ενδείξεων για ηλεκτρικό όχημα

Ντζανίδης, Ισαάκ 06 December 2013 (has links)
Στην παρούσα διπλωματική εργασία, παρουσιάζεται η ανάπτυξη συναρτήσεων και ρουτινών, οι οποίες χρησιμοποιούνται για την ψηφιακή απεικόνιση διάφορων οργάνων μέτρησης του πίνακα ενός ηλεκτρικού οχήματος, πάνω σε οθόνη TFT LCD ολοκληρωμένου συστήματος. / This diploma thesis represents the development of functions and routines wich are used to digitalize an electrical vehicle's panel using an LCD TFT screen of an embedded system (LPC2478STK).
57

The War on Drugs : En analys av The New York Times nyhetsrapportering

Stenbom, Axel January 2017 (has links)
On the 14th of July 1969 president Richard Nixon informed the United States Congress, how drugs had become a serious threat to the nation’s wellbeing. He called for a new drug policy that would be applied to both state and federal levels. This would be the start of a political campaign that has resulted in new legislation, mass incarceration and in recent year an overwhelming criticism. This essay intends to review the newspaper New York Times reporting of this political campaign. The purpose is to study the role of language in the political discourse, this through a rhetorical analysis. The thesis intends to identify the discursive process framed by the selected news articles at hand. How the magazine’s approach has changed in 20 years will not only be examined by its explicit reporting, but also through the shaping and reflecting function of language. In my analysis, I identify key themes in the general metaphorics and a reproduction of a certain role distribution that leaves the reader with a certain understanding of its contemporary time. I have also come to the conclusion that the idea of American identity is central to the war on drugs as a linguistic domain. / I ett meddelande till den amerikanska kongressen den 14 juli 1969, informerade den dåvarande presidenten Richard Nixon om hur drogerna utgjorde ett allvarligt hot mot landets välmående. Han efterlyste en ny drogpolitik som skulle gälla på både delstatlig och federal nivå. Detta blev starten på en politisk kampanj som resulterade i ny lagstiftning, massfängslande och på senare år en överväldigande kritik. Jag har i denna uppsats för avsikt att granska tidningen The New York Times rapportering av denna politiska kampanj. Syftet är att studera språkets roll i den politiska diskursen genom en retorisk analys. Jag har för avsikt att kartlägga de diskursiva processer som de valda nyhetsartiklarna ramar in. Hur tidningens förhållningssätt från har förändrats under drygt 20 år kommer inte bara granskas genom den explicita rapporteringen, utan också genom språkets formande och speglande roll. I min analys identifierar jag nyckelteman i den övergripande metaforiken och hur en reproduktion av en viss rollfördelning lämnar läsaren med viss förståelse av sin samtid. Jag har även nått slutsatsen att idén om den amerikanska identiteten är central för kriget mot droger som språklig domän.
58

Metody odhadů složitosti důkazů ve výrokové logice / Methods of proving lower bounds in propositional logic

Peterová, Alena January 2013 (has links)
In the present work, we study the propositional proof complexity. First, we prove an exponential lower bound on the complexity of resolution applying directly Razborov's approximation method, which was previously used only for bounds on the size of monotone circuits. Next, we use the approximation method for a new proof of an exponential lower bound on the complexity of random resolution refutations. That should have further applications in separating some theories in bounded arithmetic. In both cases, we use a problem from the graph theory called Broken Mosquito Screens. Finally, we state a conjecture that the approximation method is applicable even for stronger propositional proof systems, for example Cutting Plane Proofs. Powered by TCPDF (www.tcpdf.org)
59

L'archive, une puissance de nouveauté dans la pratique contemporaine de l'image en mouvement / The archive – a renewal power in the contemporary practice of moving images

Olcèse, Rodolphe 09 November 2018 (has links)
Cette thèse s’efforce de penser le remploi d’archives comme un acte de création qui signale une possibilité fondamentale du medium filmique, à même d’exercer un retour à sa propre matérialité. Pour ce faire, elle s’appuie sur l’analyse de trois films contemporains - X+ (2010) de Marylène Negro, The Uprising (2012) de Peter Snowdon et Pays barbare (2013) de Yervant Gianikian et Angela Ricci Lucchi. L’hypothèse que cette recherche entend vérifier est qu’il n’y a de cinéma que de seconde main. A partir d’une lecture des thèses de Benjamin sur le langage et la traduction, la reprise et la répétition au principe de toute expression filmique sont étudiées comme les conditions requises pour que puissent émerger des formes radicalement neuves. Les propositions filmiques analysées, en travaillant des formes fragmentaires ou en explorant la dimension polyrythmique du remploi d’images, invitent à envisager l’écran et au-delà l’archive elle-même comme des opérateurs de l’événement. Reposant sur une dimension dialogique et relationnelle de l’image filmique, le montage d’archive est indissociablement poétique et politique. Les formes qu’en proposent les artistes étudiés invitent à considérer d’un même tenant pratique filmique, archéologie des techniques et histoire des peuples. Le remploi d’archives opère un acte duel : manifester ce que le monde a été et dire dans le même temps ce qu’il peut devenir. Le montage d’archives se comprend alors comme un geste exécuté au présent, pour le présent, à travers lequel pointe l’image d’un monde ouvert. / Based on the analysis of three contemporary films (X+ by Marylène Negro, Pays barbare by Yervant Gianikian and Angela Ricci Lucchi, The Uprising by Peter Snowdon), this PhD aims to reconsider the found footage practice as a creative act that points to a fundamental potential of cinematographic media to perform a feedback on its own materiality. This PhD states as an initial hypothesis that all cinema is a second hand cinema. Using as a starting point Walter Benjamin’s works on language and translation, the reemployment and the repetition as principle of every filmic expression are considered as essential conditions for the rise of radically new forms. The topic follows three main lines : forms, rhythm and events. Theses issues are tackled in order to highlight that the cinematographic works analysed in this PhD – combining fragmentary forms or exploring the polyrhythmic dimension of found footage - allow to consider the screen and further more, the archive itself, as agents of the event. Based on the dialogic and relational dimension of moving image, the archive editing is inextricably poetic and political. Hence cinematographic practice, archaeology of techniques and political history are considered as fundamental materials by the filmmakers studied in this PhD. The reemployment as used by these artists operate a dual act : show the world as it has been and in the mean time say what this world could become. The archive editing can thus be understood as a gesture performed in the present time, for the present, a gesture that reveals the image of a world full of possibilities.
60

Recuperação de zinco e índio de monitores de computadores sucateados

Ana Cristina Vieira Zuccheratte 08 March 2013 (has links)
Este trabalho apresenta o estudo de recuperação de índio (In) e zinco (Zn) presentes em telas de monitores de computadores sucateados, por meio de técnicas hidrometalúrgicas. O trabalho foi subdividido em duas partes distintas: dissolução dos metais In e Zn mediante digestão ácida do pó de revestimento da tela de monitores e separação dos metais pela técnica de extração por solventes. Na etapa de dissolução dos metais, investigou-se a influência das seguintes variáveis de processo: tipo de reagente, relação ácido/amostra, tempo de reação e temperatura. Após a otimização dos parâmetros do processo, obteve-se uma dissolução de índio superior a 95% e de Zn superior a 99,5%. Foi obtido um licor contendo 9,8 g/L de zinco, 1,49 g/L de índio e 102 g/L de sulfato, contendo como impureza 0,016 g/L de ferro, e acidez de 2,2 mol/L (pH = 0,34). Após a definição das melhores condições de abertura química, a amostra foi processada para a obtenção do licor para a realização dos experimentos de extração por solventes. Foram realizados experimentos descontínuos de extração por solventes para a verificação da viabilidade técnica e melhores condições de separação dos metais, e um experimento contínuo para o carregamento do solvente. Na etapa de extração, as variáveis de processo investigadas foram: tipo de extratante, pH do licor e tempo de reação. Os experimentos foram realizados na relação volumétrica aquoso/orgânico (A/O) igual a 1 e concentração de extratante de 1,0 mol/L. Os extratantes investigados foram: DEHPA, IONQUEST 801 e CYANEX 272. O estudo das variáveis foi realizado apenas com os dois primeiros extratantes. Os experimentos de reextração foram realizados com HCl e H2SO4, na relação volumétrica de 1:1 e em diferentes concentrações dos ácidos. Os experimentos de bancada indicaram que a separação dos metais pode ser realizada usando DEHPA 1,0 mol/L como extratante, o H2SO4 1,0 mol/L como agente de lavagem, para a reextração dos elementos coextraídos com o índio (principalmente Zn), e HCl 3,0 mol/L para a reextração do In do orgânico carregado. / This work presents the study of recovery of indium (In) and zinc (Zn) present in computer monitor screens by means of hydrometallurgical techniques. This work was divided into two distinct parts: one is the dissolution of the metals In and Zn through acid digestion of the sample and the separation of the metals through solvent extraction technique. In the acid dissolution, the influence of the following process variables was investigated: type of reagent, acid/sample ratio, time of reaction and temperature. Following the optimisation of the parameters of the process, dissolution of indium above 98% and of Zinc over 99.5% was achieved. A liquor containing 9.8 g/L of zinc, 1.49 g/L of indium and 102 g/L of sulphate having as impurity 0.016 g/L of iron, and acidity of 2.2 mol/L (pH = 0.34) was obtained. After the optimization of the chemical opening conditions, the sample were processed in order to obtain the liquor for the solvent extraction experiments. Batch experiments of solvent extraction aiming at verifying the technical viability and best conditions for the separation of the metals and a continuous experiment to load the solvent were carried out. In the extraction phase, the process variables investigated were: type of extractant, pH of the liquor, and reaction time. The experiments were carried out at an aqueous/organic (A/O) volumetric ratio equal 1:1 and concentration of extractant 1.0 mol/L. The extractants investigated were DEHPA, IONQUEST 801 and CYANEX 272. The study of the variables was carried out with DEHPA and IONQUEST 801. The stripping experiments were carried out with HCl and H2SO4, at a volumetric ratio 1 with different acids concentrations. The batch experiments indicated that the separation of the metals In and Zn can be done using DEHPA 1 mol/L as extractant, H2SO4 1 mol/L as scrubbing agent and HCl 3 mol/L as stripping agent. After defining the best conditions for the extraction, scrubbing and stripping steps a continuous experiment was programmed. The McCabe-Thiele diagrams indicated that 3 extractions stages and 7 stripping stages was enough to extract and strip the In from the liquor and the loaded organic respectively. Due to the small amount of the liquor, the continuous experiment contemplate only the extraction and scrubbing steps. The experiment was done in mixer-settler cells, with capacity of 70 mL in the mixer and 250 mL in the settler, in a counter current system. The stripping step was carried out in batches simulating the counter current system. The continuous experiment (extraction and scrubbing steps) were carried out with the use of DEHPA 1.0 mol/L as the extractant agent and a solution of H2SO4 1.0 mol/L as the scrubbing agent in order to remove the impurities extracted. Four extraction stages and 4 stages were employed in each step, using a volumetric ratio A/O equal 5:1 in the extraction and a volumetric ration O/A equal 4:1 in the scrubbing step. A loaded organic containing 7.5 g/L of In and 0.003 g/L of Zn and a raffinad containing 9.4 g/L Zn and less than 0.001 g/L of In were obtained from a liquor containing 9.8 g/L and 1.49 g/L. The content of the metals in the stripped solution were 26.7 g/L de In e 0.001 g/L de Zn.

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