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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.
11

Transition vers la turbulence pour un fluide à seuil en écoulement dans une conduite cylindrique / Laminar-turbulent transition of a yield stress fluid in pipe flow

Esmael, Ahmed 14 November 2008 (has links)
La transition vers la turbulence pour un fluide rhéofluidifiant avec seuil en écoulement dans une conduite cylindrique est étudiée. Une analyse linéaire de stabilité est effectuée moyennant des approches modale et non modale. Les résultats numériques montrent que l'écoulement de Hagen-Poiseuille d'un fluide à seuil est linéairement stable. L'effet du comportement rhéologique du fluide sur les caractéristiques de la perturbation optimale est clairement mis en évidence. Pour de faibles valeurs du nombre d'Herschel-Bulkley (Hb << 1), la perturbation optimale se présente pratiquement sous forme de rouleaux longitudinaux et l'amplification de l'énergie est assurée par le mécanisme lift-up. Par contre pour des valeurs suffisamment élevées de Hb, la perturbation optimale est axisymétrique et l'amplification de l'énergie est assurée par le mécanisme Orr. D'un point de vue expérimental, l'écoulement d'une solution de Carbopol à 0.2 % en masse dans une conduite cylindrique est étudié à partir de la mesure des profils des vitesse axiale et analyse statistique des fluctuations de celle-ci. Il a été constaté qu'en régimes laminaire et turbulent, les profils moyens (au sens temporel) sont axisymétriques et présentent une asymétrie croissante avec le nombre de Reynolds lors de la transition. Une description tridimensionnelle de cette asymétrie a été obtenue à partir des profils de vitesse axiale mesurés à différentes positions angulaires. Les résultats obtenus suggèrent l'existence d'une structure cohérente robuste constituée de deux rouleaux longitudinaux contra-rotatifs de longueur comparable à celle du dispositif expérimental. L'analyse statistique des fluctuations de la vitesse axiale fait apparaître deux phases lors de la transition vers la turbulence. Dans la première phase, le système passe du régime laminaire à un état non linéaire asymétrique où les spectres de puissance sont très similaires à ceux observés dans le cas d'une turbulence bidimensionnelle. La deuxième phase correspond au passage de cet état asymétrique à un régime turbulent avec apparition de spots classiques de la turbulence hydrodynamique. / The transition to turbulence for shear-thinning fluid with a yield-stress in a cylindrical pipe flow is studied. A linear stability analysis is performed using modal and non-modal approches. The numerical results show that the Hagen-Poiseuille flow of yield stress fluid is linearly stable. The effect of rheological behavior of the fluid on the characteristics of the optimal perturbation is clearly highlighted. At very low Herschel-Bulkley number (Hb << 1), the optimal perturbation consists of almost streamwise vortices, and the amplification of the kinetic energy is provided by the lift-up mechanism. In contrast for sufficiently large values of $Hb$, the optimal perturbation is axisymmetric and the growth of the kinetic energy is provided by the Orr-mechanism. From experimental point of view, the flow of 0.2 wt % aqueous solution of Carbopol 940 in a pipe is investigated from the measurement of the mean, i.e., time-averaged, axial velocity profiles as well as the statistical analysis of the fluctuations. It is observed that the velocity profiles are axisymmetric in the laminar and turbulent regimes, and present an increasing asymmetry with increasing Reynolds number in the transitional regime. A three-dimensional description of this asymmetry is provided from velocity profiles measurements at different azimuthal positions. The observed transitional flow suggest the existence of a robust non-linear coherent structure characterized by two weakly modulated counter-rotating longitudinal vortices, which length is comparable to that of the test section. The statistical analysis of the axial velocity fluctuations indicate that the transition occurs essentially in two stages. The first stage corresponds to the transition from the laminar regime to a stable non linear asymmetric state, where the spectra of axial velocity fluctuations are similar to those obtained in the case of two-dimensional turbulence. The second stage corresponds to the transition from this non linear asymmetric state to the hydrodynamic turbulence with the apparition of the classical spots of turbulence.
12

Die Kölner Urkundensprache des 13. Jahrhunderts : flexionsmorphologische Untersuchungen zu den deutschen Urkunden Gottfried Hagens, 1262-1274 /

Habscheid, Stephan, January 1997 (has links)
Diss.--Universität Trier, 1995. Titre de soutenance : Flexionsmorphologische Untersuchungen zur Kölner Urkundensprache des 13.Jahrhunderts. Die deutschen Urkunden Gottfried Hagens (1262-1274). / Bibliogr. p. 255-277. Index.
13

Unitariedade de modelos de spin-3 /

Bittencourt, Raphael Schimidt. January 2019 (has links)
Orientador: Elias Leite Mendonça / Resumo: Neste trabalho propomos uma base de operadores de projeção e transição de spin para tensores de rank-3. Utilizaremos essa base para determinar os coeficientes da densidade de lagrangiana do modelo de Singh-Hagen (SH). Forneceremos uma expressão geral para obtenção do propagador para teorias de rank-3 via tensor totalmente simétrico sem quebra de paridade. Além disso, realizaremos o processo de Imersão de Calibre de Noether (ICN) no modelo SH em D dimensões e verificaremos seu conteúdo físico. Por fim iremos verificar o conteúdo físico de um novo modelo de dubleto de spin-3 de sexta ordem obtido pelo processo de solda dos modelos auto-duais de quinta e sexta ordem que não necessitam de campos auxiliares. / Abstract: In this work we suggest a basis of spin projection and transition operators for rank-3 tensors. We use it in order to determine the coefficients of the Singh-Hagen model. We also provide a general expression for obtaining the propagator for rank-3 theories via full symmetric tensor without parity breaking. In addition, we perform the Noether Gauge Embendment (NGE) procedure on the SH model in D dimensions and verify its particle content. Finally we analyze the unitarity of a new sixth-order spin-3 doublet model obtained through the soldering approach of the fifth and sixth order self-dual models which do not require auxiliary fields. / Mestre
14

“Hagene, der vil ungetriuwe man”? Courtly Rivalry, Loyalty Conflict, and the Figure of Hagen in the Nibelungenlied

DeVane Brown, Katherine 29 August 2014 (has links)
The variety of scholarly approaches to the Middle High German poem Das Nibelungenlied has generated a wide range of conflicting analyses of the character of Hagen, a figure who plays a key role in both the plot and the interpretation of the work. This thesis proposes that viewing Hagen’s relationship with Siegfried in relation to the poem’s central theme of loyalty (triuwe) allows for an analysis that integrates both the positive and negative aspects of Hagen’s character. By examining the depiction of courtly rivalry in four contemporary Middle High German works (Herzog Ernst B, Wolfdietrich A, Tristan, and Parzival), I outline the basic features of this common medieval narrative structure and then apply the same framework to a close reading of the relationship between Hagen and Siegfried in the Nibelungenlied. I also argue that the incorporation of the courtly rivalry motif as a unifying theme of the text allows the poet to take a stance on the broader issue of loyalty conflict, a topic which appears frequently in contemporary literature and had particular relevance within the political climate of medieval Germany. My reading of the character of Hagen can thus hopefully shed new light on the thematic structure of the Nibelungenlied as well as on the relationship between the poem and the literary and historical context in which it was written.
15

LDL-Apherese verbessert die Mikrozirkulation der oberen Extremitäten / Lipid-Apheresis Improves Microcirculation of the Upper Limbs

Rossenbach, Jannik 05 March 2012 (has links)
No description available.
16

Natur und Zivilisation in der Musik: Theodor Hagen, Marx und Goethe. Ein ideengeschichtliches Tableau

Sühring, Peter 19 February 2021 (has links)
In einer direkten Konfrontation der zwischen 1844 und 1852 von beiden geschriebenen Artikel, Bücher und Briefe wird versucht, die wenigen Gemeinsamkeiten und die vielen Trennungspunkte zwischen Marx und Hagen, zwei linken Achtundvierzigern und Mitgliedern des Bundes der Kommunisten, in Bezug auf die Begriffe Zivilisation und Musik darzustellen. Mit dem Ergebnis, dass bezogen auf Musik von Marx wenig zu erfahren ist und bezogen auf die Zivilisation der bürgerlichen Gesellschaft beide Autoren ziemlich entgegengesetzte Ansichten hegten. Während Marx in der Herrschaft der Bourgeoisie ein notwendiges Durchgangsstadium im weltgeschichtlichen Prozess sah, die durch eine Revolutionierung der Produktionsverhältnisse beseitigt werden würde, sah Hagen in der Zivilisation den entscheidenden Hinderungsgrund für eine Emanzipation des Volkes und der Arbeiterklasse, die zuvörderst mittels der Musik geschwächt und beseitigt werden müsse, um an einen Sieg über das Bürgertum denken zu können. Marx’ Idealisierung der materiellen Produktion und Hagens Idealisierung der Musik als Befreiungsmittel werden durch Hinweise auf nur zwanzig Jahre ältere Gedanken von Goethe korrigiert. / In a direct confrontation of the articles, books and letters written by both between 1844 and 1852, an attempt is made to illustrate the few similarities and the many dividing points between Marx and Hagen, two left-wing forty-eighties and members of the Communist League, in relation to their concepts of civilization and music. With the result that there is little to be learned by Marx in relation to music and that in relation to civilization of bourgeois society both authors had rather opposite views. While Marx saw the rule of the bourgeoisie as a necessary stage in the process of world history, which would be eliminated by a revolution in the conditions of production, Hagen saw civilization as the decisive obstacle to the emancipation of the people and the working class, which was primarily weakened and eliminated by music to be able to think of a victory over the bourgeois class. Marx’s idealization of material production and Hagen’s idealization of music as a means of liberation are corrected by references to Goethe’s ideas that are only twenty years older.
17

Seletividade de inseticidas utilizados no meloeiro sobre Chrysoperla genanigra Freitas e Chrysoperla externa HAGEN (Neuroptera: Chrysopidae). / Selectivity of insecticides used in melon on Chrysoperla genanigra Freitas and Chrysoperla externa HAGEN (Neuroptera: Chrysopidae).

LEITE, Delzuite Teles. 10 May 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-05-10T14:37:36Z No. of bitstreams: 1 DELZUITE TELES LEITE - DISSERTAÇÃO PPGHT 2014..pdf: 725468 bytes, checksum: 544a41814b10bf7b892a5b7b656a15db (MD5) / Made available in DSpace on 2018-05-10T14:37:36Z (GMT). No. of bitstreams: 1 DELZUITE TELES LEITE - DISSERTAÇÃO PPGHT 2014..pdf: 725468 bytes, checksum: 544a41814b10bf7b892a5b7b656a15db (MD5) Previous issue date: 2014-03-13 / Capes / Para que predadores de insetos pragas sejam utilizados no cultivo de melão, associados a produtos fitossanitários, é necessário que esses produtos sejam seletivos a inimigos naturais. Neste sentido, o objetivo deste trabalho foi avaliar os efeitos tóxicos de alguns inseticidas utilizados no cultivo do meloeiro para o controle de pragas, sobre ovos de Chrysoperla genanigra e larvas de Chrysoperla externa, analisando igualmente os efeitos sobre as fases subsequentes do desenvolvimento dos estágios contaminados dos predadores. Os ensaios foram desenvolvidos no Laboratório de Seletividade de Produtos Fitossanitários do Setor de Fitossanidade do Departamento de Ciências Vegetais da Universidade Federal Rural do Semiárido. Os experimentos foram realizados de acordo com a metodologia padrão da International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Os produtos testados com suas respectivas dosagens (g do igrediente ativo/ L de água) foram: Clotianidina (0,1), Pimetrozina (0,25), Lambda-Cialotrina (0,025), Clorantraniliprole (0,0025), Indoxacarbe (0,036), Piriproxifem (0,1), Beta-Ciflutrina/ Imidacloprido (0,0625 +0,5), Imidacloprido (1,05) e Beta-Cipermetrina (0,04), o controle foi composto apenas por água destilada. As aplicações dos produtos foram realizadas com pulverizador pressurizado manualmente. No primeiro experimento as aplicações dos inseticidas foram efetuadas sobre os ovos de C. genanigra em placas de Petri, em seguida foram individualizados em tubos de vidro de 2,0 cm de diâmetro por 8,0 cm de altura, vedados na sua parte superior com filme plástico de cloreto de polivinila (PVC) e mantidos em sala climatizada a 25 ± 2 ºC, UR 70 ± 10% e 12h de fotofase. Os parâmetros biológicos avaliados foram à duração e sobrevivência da fase imatura, a razão sexual dos adultos provenientes dos ovos tratados, como também a oviposição média total/ fêmea no período avaliado e a viabilidade dos ovos da progênie. No segundo experimento a aplicação dos tratamentos foram indiretos para larvas de C. externa, aplicados sobre placas de Petri com posterior liberação das larvas, prosseguindo os passos do primeiro experimento. Avaliou-se duração e sobrevivência da fase imatura, a razão sexual dos adultos provenientes dos ovos tratados, como também a oviposição média total/ fêmea no período avaliado e a viabilidade dos ovos da progênie. O Lambda-cialotrina, Indoxacarbe, Pimetrozinae o Imidacloprido foram seletivos para a espécie C. genanigra, enquanto que o Clotiadinina, Beta-cipermetrina, Beta-ciflutrina/ Imidacloprido, Clorantraniliprole e o Piriproxifem foram tóxicos para esta espécie. Para larvas de C. externa, os inseticidas Pimetrozina e o Clorantraniliprole foram seletivos, enquanto que o Clotiadinina, Lambda-cialotrina, Indoxacarbe, Piriproxifem, Beta-ciflutina/ Imidacloprido, Imidacloprido e o Beta-cipermetrina se mostraram tóxicos. / For predators of pest insects are used in melon cultivation, associated with pesticides, it is necessary that those products are selective to natural enemies. In this sense, the aim of this study was to evaluate the toxic effects of some insecticides used in melon cultivation to control pests on eggs of Chrysoperla genanigra and larvae of Chrysoperla externa, also analyzing the effects on the subsequent phases of the development of contaminated predators stages. The tests were developed in the Laboratory of Selectivity of Plant Protection Products Sector of the Plant Protection Department of Plant Sciences, Federal Rural University of the Semi-Arid. The experiments were performed according to the standard methodology of the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). Products tested with their respective strengths (assets g / L igrediente water) were Chlothianidin (0.1), Pymetrozine (0.25), Lambda-cyhalothrin (0.025), Clorantraniliprole (0.0025), Indoxacarb (0.036 ), pyriproxyfen (0.1), Beta-cyfluthrin / Imidacloprid (0.0625 +0.5), Imidacloprid (1.05) and Beta-Cypermethrin (0.04), the control was only composed of distilled water. The applications of the products were performed manually pressurized spray. In the first experiment insecticide applications were made on the egg genanigra C. in Petri dishes were then individually in glass tubes of 2.0 cm diameter by 8.0 cm tall sealed in its upper part with plastic film of polyvinyl chloride (PVC) and kept under controlled environmental conditions at 25 ± 2 º C, 70 ± 10% UR and 12h photophase. The parameters evaluated were the duration and survival of the immature stage, the sex ratio of adults from treated eggs as well as the total average oviposition / female in the study period and egg viability of the progeny. In the second experiment the treatments were indirect larvae of C. externa, on a Petri dish with subsequent release of larvae, continuing in the footsteps of the first experiment. We assessed duration and survival of the immature stage, the sex ratio of adults from treated eggs as well as the total average oviposition / female in the study period and egg viability of the progeny. Lambdacyhalothrin, indoxacarb and Pymetrozine Imidacloprid were selective for the species C. genanigra, while clothianidin, beta-cypermethrin, beta-cyfluthrin / Imidacloprid, Pyriproxyfen and Clorantraniliprole were toxic for this species. For larvae of C. externa, and the Pymetrozine Clorantraniliprole insecticides were harmless, whereas clothianidin, Lambda-cyhalothrin, indoxacarb pyriproxyfen, Beta-ciflutina / Imidacloprid, Imidacloprid and Beta-cypermethrin proved toxic.
18

Satellite meteorology in the cold war era: scientific coalitions and international leadership 1946-1964

Callahan, Angelina Long 13 January 2014 (has links)
In tracing the history of the TIROS meteorological satellite system, this dissertation details the convergence of two communities: the DOD space scientists who established US capability to launch and operate these remote sensing systems and the US Weather Bureau meteorologists who would be the managers and users of satellite data. Between 1946 and 1964, these persons participated in successive coalitions. These coalitions were necessary in part because satellite systems were too big—geographically, fiscally, and technically—to be developed and operated within a single institution. Thus, TIROS technologies and people trace their roots to several research centers—institutions that the USWB and later NASA attempted to coordinate for US R&D. The gradual transfer of persons and hardware from the armed services to the non-military NASA sheds light on the US’s evolution as a Cold War global power, shaped from the “top-down” (by the executive and legislative branches) as well as the “bottom-up” (by military and non-military scientific communities). Through these successive coalitions, actor terms centered on “basic science” or the circulation of atmospheric data were used to help define bureaucratic places (the Upper Atmospheric Rocket Research Panel, International Geophysical Year, NASA, and the World Weather Watch) in which basic research would be supported by sustained and collaboration could take place with international partners.
19

Image Segmentation, Parametric Study, and Supervised Surrogate Modeling of Image-based Computational Fluid Dynamics

Islam, Md Mahfuzul 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / With the recent advancement of computation and imaging technology, Image-based computational fluid dynamics (ICFD) has emerged as a great non-invasive capability to study biomedical flows. These modern technologies increase the potential of computation-aided diagnostics and therapeutics in a patient-specific environment. I studied three components of this image-based computational fluid dynamics process in this work. To ensure accurate medical assessment, realistic computational analysis is needed, for which patient-specific image segmentation of the diseased vessel is of paramount importance. In this work, image segmentation of several human arteries, veins, capillaries, and organs was conducted to use them for further hemodynamic simulations. To accomplish these, several open-source and commercial software packages were implemented. This study incorporates a new computational platform, called InVascular, to quantify the 4D velocity field in image-based pulsatile flows using the Volumetric Lattice Boltzmann Method (VLBM). We also conducted several parametric studies on an idealized case of a 3-D pipe with the dimensions of a human renal artery. We investigated the relationship between stenosis severity and Resistive index (RI). We also explored how pulsatile parameters like heart rate or pulsatile pressure gradient affect RI. As the process of ICFD analysis is based on imaging and other hemodynamic data, it is often time-consuming due to the extensive data processing time. For clinicians to make fast medical decisions regarding their patients, we need rapid and accurate ICFD results. To achieve that, we also developed surrogate models to show the potential of supervised machine learning methods in constructing efficient and precise surrogate models for Hagen-Poiseuille and Womersley flows.
20

Tlakové ztráty nosičů katalyzátorů / Pressure loss of catalyst carriers

Linda, Matúš January 2018 (has links)
The diploma thesis is divided into four main parts. The first part deals with the issue of waste management and its energy utilization in waste incineration. Processed harmful substances produced by incineration as well as emission limits. It deals with the types of catalytic carriers, their description, production and more detailed processing of ceramic foam VUKOPOR. The second part is devoted to technologies utilizing catalytic processes and a more detailed specification of the process. In the third part there is processed the calculation methods for pressure losses for individual types of carriers. Fourth, the most extensive part describes the INTEQII experimental device, its technology and construction, as well as the principle of the practical part, measuring of the pressure losses of carriers. It includes the evaluation of pressure losses in separate categories of carriers, such as the bed, HoneyComb and VUKOPOR ceramic foam. Subsequently, a comparison of the pressure losses of all carriers is made relative to the reference size of 1 m. The impact of bonding of VUKOPOR foam samples on the size of pressure losses is discussed. At the end of this section, the suitability of calculation methods for individual carriers is evaluated, depending on the experimental pressure loss data.

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